Diffraction-based overlay metrology for double patterning technologies

NASA Astrophysics Data System (ADS)

Dasari, Prasad; Korlahalli, Rahul; Li, Jie; Smith, Nigel; Kritsun, Oleg; Volkman, Cathy

2009-03-01

The extension of optical lithography to 32nm and beyond is made possible by Double Patterning Techniques (DPT) at critical levels of the process flow. The ease of DPT implementation is hindered by increased significance of critical dimension uniformity and overlay errors. Diffraction-based overlay (DBO) has shown to be an effective metrology solution for accurate determination of the overlay errors associated with double patterning [1, 2] processes. In this paper we will report its use in litho-freeze-litho-etch (LFLE) and spacer double patterning technology (SDPT), which are pitch splitting solutions that reduce the significance of overlay errors. Since the control of overlay between various mask/level combinations is critical for fabrication, precise and accurate assessment of errors by advanced metrology techniques such as spectroscopic diffraction based overlay (DBO) and traditional image-based overlay (IBO) using advanced target designs will be reported. A comparison between DBO, IBO and CD-SEM measurements will be reported. . A discussion of TMU requirements for 32nm technology and TMU performance data of LFLE and SDPT targets by different overlay approaches will be presented.

Simultaneous overlay and CD measurement for double patterning: scatterometry and RCWA approach

NASA Astrophysics Data System (ADS)

Li, Jie; Liu, Zhuan; Rabello, Silvio; Dasari, Prasad; Kritsun, Oleg; Volkman, Catherine; Park, Jungchul; Singh, Lovejeet

2009-03-01

As optical lithography advances to 32 nm technology node and beyond, double patterning technology (DPT) has emerged as an attractive solution to circumvent the fundamental optical limitations. DPT poses unique demands on critical dimension (CD) uniformity and overlay control, making the tolerance decrease much faster than the rate at which critical dimension shrinks. This, in turn, makes metrology even more challenging. In the past, multi-pad diffractionbased overlay (DBO) using empirical approach has been shown to be an effective approach to measure overlay error associated with double patterning [1]. In this method, registration errors for double patterning were extracted from specially designed diffraction targets (three or four pads for each direction); CD variation is assumed negligible within each group of adjacent pads and not addressed in the measurement. In another paper, encouraging results were reported with a first attempt at simultaneously extracting overlay and CD parameters using scatterometry [2]. In this work, we apply scatterometry with a rigorous coupled wave analysis (RCWA) approach to characterize two double-patterning processes: litho-etch-litho-etch (LELE) and litho-freeze-litho-etch (LFLE). The advantage of performing rigorous modeling is to reduce the number of pads within each measurement target, thus reducing space requirement and improving throughput, and simultaneously extract CD and overlay information. This method measures overlay errors and CDs by fitting the optical signals with spectra calculated from a model of the targets. Good correlation is obtained between the results from this method and that of several reference techniques, including empirical multi-pad DBO, CD-SEM, and IBO. We also perform total measurement uncertainty (TMU) analysis to evaluate the overall performance. We demonstrate that scatterometry provides a promising solution to meet the challenging overlay metrology requirement in DPT.

64nm pitch metal1 double patterning metrology: CD and OVL control by SEMCD, image based overlay and diffraction based overlay

NASA Astrophysics Data System (ADS)

Ducoté, Julien; Dettoni, Florent; Bouyssou, Régis; Le-Gratiet, Bertrand; Carau, Damien; Dezauzier, Christophe

2015-03-01

Patterning process control of advanced nodes has required major changes over the last few years. Process control needs of critical patterning levels since 28nm technology node is extremely aggressive showing that metrology accuracy/sensitivity must be finely tuned. The introduction of pitch splitting (Litho-Etch-Litho-Etch) at 14FDSOInm node requires the development of specific metrologies to adopt advanced process control (for CD, overlay and focus corrections). The pitch splitting process leads to final line CD uniformities that are a combination of the CD uniformities of the two exposures, while the space CD uniformities are depending on both CD and OVL variability. In this paper, investigations of CD and OVL process control of 64nm minimum pitch at Metal1 level of 14FDSOI technology, within the double patterning process flow (Litho, hard mask etch, line etch) are presented. Various measurements with SEMCD tools (Hitachi), and overlay tools (KT for Image Based Overlay - IBO, and ASML for Diffraction Based Overlay - DBO) are compared. Metrology targets are embedded within a block instanced several times within the field to perform intra-field process variations characterizations. Specific SEMCD targets were designed for independent measurement of both line CD (A and B) and space CD (A to B and B to A) for each exposure within a single measurement during the DP flow. Based on those measurements correlation between overlay determined with SEMCD and with standard overlay tools can be evaluated. Such correlation at different steps through the DP flow is investigated regarding the metrology type. Process correction models are evaluated with respect to the measurement type and the intra-field sampling.

Next generation of decision making software for nanopatterns characterization: application to semiconductor industry

NASA Astrophysics Data System (ADS)

Dervilllé, A.; Labrosse, A.; Zimmermann, Y.; Foucher, J.; Gronheid, R.; Boeckx, C.; Singh, A.; Leray, P.; Halder, S.

2016-03-01

The dimensional scaling in IC manufacturing strongly drives the demands on CD and defect metrology techniques and their measurement uncertainties. Defect review has become as important as CD metrology and both of them create a new metrology paradigm because it creates a completely new need for flexible, robust and scalable metrology software. Current, software architectures and metrology algorithms are performant but it must be pushed to another higher level in order to follow roadmap speed and requirements. For example: manage defect and CD in one step algorithm, customize algorithms and outputs features for each R&D team environment, provide software update every day or every week for R&D teams in order to explore easily various development strategies. The final goal is to avoid spending hours and days to manually tune algorithm to analyze metrology data and to allow R&D teams to stay focus on their expertise. The benefits are drastic costs reduction, more efficient R&D team and better process quality. In this paper, we propose a new generation of software platform and development infrastructure which can integrate specific metrology business modules. For example, we will show the integration of a chemistry module dedicated to electronics materials like Direct Self Assembly features. We will show a new generation of image analysis algorithms which are able to manage at the same time defect rates, images classifications, CD and roughness measurements with high throughput performances in order to be compatible with HVM. In a second part, we will assess the reliability, the customization of algorithm and the software platform capabilities to follow new specific semiconductor metrology software requirements: flexibility, robustness, high throughput and scalability. Finally, we will demonstrate how such environment has allowed a drastic reduction of data analysis cycle time.

Sub-50 nm metrology on extreme ultra violet chemically amplified resist—A systematic assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maas, D. J., E-mail: diederik.maas@tno.nl; Herfst, R.; Veldhoven, E. van

2015-10-15

With lithographic patterning dimensions decreasing well below 50 nm, it is of high importance to understand metrology at such small scales. This paper presents results obtained from dense arrays of contact holes (CHs) with various Critical Dimension (CD) between 15 and 50 nm, as patterned in a chemically amplified resist using an ASML EUV scanner and measured at ASML and TNO. To determine the differences between various (local) CD metrology techniques, we conducted an experiment using optical scatterometry, CD-Scanning Electron Microscopy (CD-SEM), Helium ion Microscopy (HIM), and Atomic Force Microscopy (AFM). CD-SEM requires advanced beam scan strategies to mitigate samplemore » charging; the other tools did not need that. We discuss the observed main similarities and differences between the various techniques. To this end, we assessed the spatial frequency content in the raw images for SEM, HIM, and AFM. HIM and AFM resolve the highest spatial frequencies, which are attributed to the more localized probe-sample interaction for these techniques. Furthermore, the SEM, HIM, and AFM waveforms are analyzed in detail. All techniques show good mutual correlation, albeit the reported CD values systematically differ significantly. HIM systematically reports a 25% higher CD uniformity number than CD-SEM for the same arrays of CHs, probably because HIM has a higher resolution than the CD-SEM used in this assessment. A significant speed boost for HIM and AFM is required before these techniques are to serve the demanding industrial metrology applications like optical critical dimension and CD-SEM do nowadays.« less

Sub-50 nm metrology on extreme ultra violet chemically amplified resist—A systematic assessment

NASA Astrophysics Data System (ADS)

Maas, D. J.; Fliervoet, T.; Herfst, R.; van Veldhoven, E.; Meessen, J.; Vaenkatesan, V.; Sadeghian, H.

2015-10-01

With lithographic patterning dimensions decreasing well below 50 nm, it is of high importance to understand metrology at such small scales. This paper presents results obtained from dense arrays of contact holes (CHs) with various Critical Dimension (CD) between 15 and 50 nm, as patterned in a chemically amplified resist using an ASML EUV scanner and measured at ASML and TNO. To determine the differences between various (local) CD metrology techniques, we conducted an experiment using optical scatterometry, CD-Scanning Electron Microscopy (CD-SEM), Helium ion Microscopy (HIM), and Atomic Force Microscopy (AFM). CD-SEM requires advanced beam scan strategies to mitigate sample charging; the other tools did not need that. We discuss the observed main similarities and differences between the various techniques. To this end, we assessed the spatial frequency content in the raw images for SEM, HIM, and AFM. HIM and AFM resolve the highest spatial frequencies, which are attributed to the more localized probe-sample interaction for these techniques. Furthermore, the SEM, HIM, and AFM waveforms are analyzed in detail. All techniques show good mutual correlation, albeit the reported CD values systematically differ significantly. HIM systematically reports a 25% higher CD uniformity number than CD-SEM for the same arrays of CHs, probably because HIM has a higher resolution than the CD-SEM used in this assessment. A significant speed boost for HIM and AFM is required before these techniques are to serve the demanding industrial metrology applications like optical critical dimension and CD-SEM do nowadays.

Investigation of hyper-NA scanner emulation for photomask CDU performance

NASA Astrophysics Data System (ADS)

Poortinga, Eric; Scheruebl, Thomas; Conley, Will; Sundermann, Frank

2007-02-01

As the semiconductor industry moves toward immersion lithography using numerical apertures above 1.0 the quality of the photomask becomes even more crucial. Photomask specifications are driven by the critical dimension (CD) metrology within the wafer fab. Knowledge of the CD values at resist level provides a reliable mechanism for the prediction of device performance. Ultimately, tolerances of device electrical properties drive the wafer linewidth specifications of the lithography group. Staying within this budget is influenced mainly by the scanner settings, resist process, and photomask quality. Tightening of photomask specifications is one mechanism for meeting the wafer CD targets. The challenge lies in determining how photomask level metrology results influence wafer level imaging performance. Can it be inferred that photomask level CD performance is the direct contributor to wafer level CD performance? With respect to phase shift masks, criteria such as phase and transmission control are generally tightened with each technology node. Are there other photomask relevant influences that effect wafer CD performance? A comprehensive study is presented supporting the use of scanner emulation based photomask CD metrology to predict wafer level within chip CD uniformity (CDU). Using scanner emulation with the photomask can provide more accurate wafer level prediction because it inherently includes all contributors to image formation related to the 3D topography such as the physical CD, phase, transmission, sidewall angle, surface roughness, and other material properties. Emulated images from different photomask types were captured to provide CD values across chip. Emulated scanner image measurements were completed using an AIMS TM45-193i with its hyper-NA, through-pellicle data acquisition capability including the Global CDU Map TM software option for AIMS TM tools. The through-pellicle data acquisition capability is an essential prerequisite for capturing final CDU data (after final clean and pellicle mounting) before the photomask ships or for re-qualification at the wafer fab. Data was also collected on these photomasks using a conventional CD-SEM metrology system with the pellicles removed. A comparison was then made to wafer prints demonstrating the benefit of using scanner emulation based photomask CD metrology.

Photomask applications of traceable atomic force microscope dimensional metrology at NIST

NASA Astrophysics Data System (ADS)

Dixson, Ronald; Orji, Ndubuisi G.; Potzick, James; Fu, Joseph; Allen, Richard A.; Cresswell, Michael; Smith, Stewart; Walton, Anthony J.; Tsiamis, Andreas

2007-10-01

The National Institute of Standards and Technology (NIST) has a multifaceted program in atomic force microscope (AFM) dimensional metrology. Three major instruments are being used for traceable measurements. The first is a custom in-house metrology AFM, called the calibrated AFM (C-AFM), the second is the first generation of commercially available critical dimension AFM (CD-AFM), and the third is a current generation CD-AFM at SEMATECH - for which NIST has established the calibration and uncertainties. All of these instruments have useful applications in photomask metrology. Linewidth reference metrology is an important application of CD-AFM. We have performed a preliminary comparison of linewidths measured by CD-AFM and by electrical resistance metrology on a binary mask. For the ten selected test structures with on-mask linewidths between 350 nm and 600 nm, most of the observed differences were less than 5 nm, and all of them were less than 10 nm. The offsets were often within the estimated uncertainties of the AFM measurements, without accounting for the effect of linewidth roughness or the uncertainties of electrical measurements. The most recent release of the NIST photomask standard - which is Standard Reference Material (SRM) 2059 - was also supported by CD-AFM reference measurements. We review the recent advances in AFM linewidth metrology that will reduce the uncertainty of AFM measurements on this and future generations of the NIST photomask standard. The NIST C-AFM has displacement metrology for all three axes traceable to the 633 nm wavelength of the iodine-stabilized He-Ne laser. One of the important applications of the C-AFM is step height metrology, which has some relevance to phase shift calibration. In the current generation of the system, the approximate level of relative standard uncertainty for step height measurements at the 100 nm scale is 0.1 %. We discuss the monitor history of a 290 nm step height, originally measured on the C-AFM with a 1.9 nm (k = 2) expanded uncertainty, and describe advances that bring the step height uncertainty of recent measurements to an estimated 0.6 nm (k = 2). Based on this work, we expect to be able to reduce the topographic component of phase uncertainty in alternating aperture phase shift masks (AAPSM) by a factor of three compared to current calibrations based on earlier generation step height references.

Patterning control strategies for minimum edge placement error in logic devices

NASA Astrophysics Data System (ADS)

Mulkens, Jan; Hanna, Michael; Slachter, Bram; Tel, Wim; Kubis, Michael; Maslow, Mark; Spence, Chris; Timoshkov, Vadim

2017-03-01

In this paper we discuss the edge placement error (EPE) for multi-patterning semiconductor manufacturing. In a multi-patterning scheme the creation of the final pattern is the result of a sequence of lithography and etching steps, and consequently the contour of the final pattern contains error sources of the different process steps. We describe the fidelity of the final pattern in terms of EPE, which is defined as the relative displacement of the edges of two features from their intended target position. We discuss our holistic patterning optimization approach to understand and minimize the EPE of the final pattern. As an experimental test vehicle we use the 7-nm logic device patterning process flow as developed by IMEC. This patterning process is based on Self-Aligned-Quadruple-Patterning (SAQP) using ArF lithography, combined with line cut exposures using EUV lithography. The computational metrology method to determine EPE is explained. It will be shown that ArF to EUV overlay, CDU from the individual process steps, and local CD and placement of the individual pattern features, are the important contributors. Based on the error budget, we developed an optimization strategy for each individual step and for the final pattern. Solutions include overlay and CD metrology based on angle resolved scatterometry, scanner actuator control to enable high order overlay corrections and computational lithography optimization to minimize imaging induced pattern placement errors of devices and metrology targets.

Advanced metrology by offline SEM data processing

NASA Astrophysics Data System (ADS)

Lakcher, Amine; Schneider, Loïc.; Le-Gratiet, Bertrand; Ducoté, Julien; Farys, Vincent; Besacier, Maxime

2017-06-01

Today's technology nodes contain more and more complex designs bringing increasing challenges to chip manufacturing process steps. It is necessary to have an efficient metrology to assess process variability of these complex patterns and thus extract relevant data to generate process aware design rules and to improve OPC models. Today process variability is mostly addressed through the analysis of in-line monitoring features which are often designed to support robust measurements and as a consequence are not always very representative of critical design rules. CD-SEM is the main CD metrology technique used in chip manufacturing process but it is challenged when it comes to measure metrics like tip to tip, tip to line, areas or necking in high quantity and with robustness. CD-SEM images contain a lot of information that is not always used in metrology. Suppliers have provided tools that allow engineers to extract the SEM contours of their features and to convert them into a GDS. Contours can be seen as the signature of the shape as it contains all the dimensional data. Thus the methodology is to use the CD-SEM to take high quality images then generate SEM contours and create a data base out of them. Contours are used to feed an offline metrology tool that will process them to extract different metrics. It was shown in two previous papers that it is possible to perform complex measurements on hotspots at different process steps (lithography, etch, copper CMP) by using SEM contours with an in-house offline metrology tool. In the current paper, the methodology presented previously will be expanded to improve its robustness and combined with the use of phylogeny to classify the SEM images according to their geometrical proximities.

Resolving critical dimension drift over time in plasma etching through virtual metrology based wafer-to-wafer control

NASA Astrophysics Data System (ADS)

Lee, Ho Ki; Baek, Kye Hyun; Shin, Kyoungsub

2017-06-01

As semiconductor devices are scaled down to sub-20 nm, process window of plasma etching gets extremely small so that process drift or shift becomes more significant. This study addresses one of typical process drift issues caused by consumable parts erosion over time and provides feasible solution by using virtual metrology (VM) based wafer-to-wafer control. Since erosion of a shower head has center-to-edge area dependency, critical dimensions (CDs) at the wafer center and edge area get reversed over time. That CD trend is successfully estimated on a wafer-to-wafer basis by a partial least square (PLS) model which combines variables from optical emission spectroscopy (OES), VI-probe and equipment state gauges. R 2 of the PLS model reaches 0.89 and its prediction performance is confirmed in a mass production line. As a result, the model can be exploited as a VM for wafer-to-wafer control. With the VM, advanced process control (APC) strategy is implemented to solve the CD drift. Three σ of CD across wafer is improved from the range (1.3-2.9 nm) to the range (0.79-1.7 nm). Hopefully, results introduced in this paper will contribute to accelerating implementation of VM based APC strategy in semiconductor industry.

SAQP pitch walk metrology using single target metrology

NASA Astrophysics Data System (ADS)

Fang, Fang; Herrera, Pedro; Kagalwala, Taher; Camp, Janay; Vaid, Alok; Pandev, Stilian; Zach, Franz

2017-03-01

Self-aligned quadruple patterning (SAQP) processes have found widespread acceptance in advanced technology nodes to drive device scaling beyond the resolution limitations of immersion scanners. Of the four spaces generated in this process from one lithography pattern two tend to be equivalent as they are derived from the first spacer deposition. The three independent spaces are commonly labelled as α, β and γ. α, β and γ are controlled by multiple process steps including the initial lithographic patterning process, the two mandrel and spacer etches as well as the two spacer depositions. Scatterometry has been the preferred metrology approach, however is restricted to repetitive arrays. In these arrays independent measurements, in particular of alpha and gamma, are not possible due to degeneracy of the standard array targets. . In this work we present a single target approach which lifts the degeneracies commonly encountered while using product relevant layout geometries. We will first describe the metrology approach which includes the previously described SRM (signal response metrology) combined with reference data derived from CD SEM data. The performance of the methodology is shown in figures 1-3. In these figures the optically determined values for alpha, beta and gamma are compared to the CD SEM reference data. The variations are achieved using controlled process experiments varying Mandrel CD and Spacer deposition thicknesses.

CD-SEM real time bias correction using reference metrology based modeling

NASA Astrophysics Data System (ADS)

Ukraintsev, V.; Banke, W.; Zagorodnev, G.; Archie, C.; Rana, N.; Pavlovsky, V.; Smirnov, V.; Briginas, I.; Katnani, A.; Vaid, A.

2018-03-01

Accuracy of patterning impacts yield, IC performance and technology time to market. Accuracy of patterning relies on optical proximity correction (OPC) models built using CD-SEM inputs and intra die critical dimension (CD) control based on CD-SEM. Sub-nanometer measurement uncertainty (MU) of CD-SEM is required for current technologies. Reported design and process related bias variation of CD-SEM is in the range of several nanometers. Reference metrology and numerical modeling are used to correct SEM. Both methods are slow to be used for real time bias correction. We report on real time CD-SEM bias correction using empirical models based on reference metrology (RM) data. Significant amount of currently untapped information (sidewall angle, corner rounding, etc.) is obtainable from SEM waveforms. Using additional RM information provided for specific technology (design rules, materials, processes) CD extraction algorithms can be pre-built and then used in real time for accurate CD extraction from regular CD-SEM images. The art and challenge of SEM modeling is in finding robust correlation between SEM waveform features and bias of CD-SEM as well as in minimizing RM inputs needed to create accurate (within the design and process space) model. The new approach was applied to improve CD-SEM accuracy of 45 nm GATE and 32 nm MET1 OPC 1D models. In both cases MU of the state of the art CD-SEM has been improved by 3x and reduced to a nanometer level. Similar approach can be applied to 2D (end of line, contours, etc.) and 3D (sidewall angle, corner rounding, etc.) cases.

A new way of measuring wiggling pattern in SADP for 3D NAND technology

NASA Astrophysics Data System (ADS)

Mi, Jian; Chen, Ziqi; Tu, Li Ming; Mao, Xiaoming; Liu, Gong Cai; Kawada, Hiroki

2018-03-01

A new metrology method of quantitatively measuring wiggling patterns in a Self-Aligned Double Patterning (SADP) process for 2D NAND technology has been developed with a CD-SEM metrology program on images from a Review-SEM system. The metrology program provided accurate modeling of various wiggling patterns. The Review-SEM system provided a-few-micrometer-wide Field of View (FOV), which exceeds precision-guaranteed FOV of a conventional CD-SEM. The result has been effectively verified by visual inspection on vertically compressed images compared with Wiggling Index from this new method. A best-known method (BKM) system has been developed with connected HW and SW to automatically measure wiggling patterns.

Advanced optical imaging platform for CD metrology and defect review on 130-nm to 100-nm node reticles: an overview of preliminary results

NASA Astrophysics Data System (ADS)

Hourd, Andrew C.; Grimshaw, Anthony; Scheuring, Gerd; Gittinger, Christian; Brueck, Hans-Juergen; Chen, Shiuh-Bin; Chen, Parkson W.; Hartmann, Hans; Ordynskyy, Volodymyr; Jonckheere, Rik M.; Philipsen, Vicky; Schaetz, Thomas; Sommer, Karl

2002-08-01

Critical Dimension fidelity continues to be one of the key driving parameters defining photomask quality and printing performance. The present advanced optical CD metrology systems, operating at i-line, will very soon be challenged as viable tools owing to their restricted resolution and measurement linearity impact on the ability to produce repeatable measurements. Alternative measurement technologies such as CD-SEM and -AFM have started to appear, but are also not without tier concerns in the field of reticle CD metrology. This paper introduces a new optical metrology system (MueTec /) operating at DUV wavelength (248nm), which has been specifically designed to meet the resolution and measurement repeatability requirements of reticle manufacture at the 130nm and 100nm nodes. The system is based upon a specially designed mechanical-optical platform for maximum stability and very advanced optical, illumination, alignment and software systems. The at wavelength operation of this system also makes it an ideal platform for defect printability analysis and review. The system is currently part of a European Commission funded assessment project (IST-2000-28086: McD'OR) to develop a testing strategy to verify the system performance, agree on equipment specifications and demonstrate its capability on advanced production reticles - including long-term reliability. It is the preliminary results from this evaluation that are presented here.

Reducing measurement uncertainty drives the use of multiple technologies for supporting metrology

NASA Astrophysics Data System (ADS)

Banke, Bill, Jr.; Archie, Charles N.; Sendelbach, Matthew; Robert, Jim; Slinkman, James A.; Kaszuba, Phil; Kontra, Rick; DeVries, Mick; Solecky, Eric P.

2004-05-01

Perhaps never before in semiconductor microlithography has there been such an interest in the accuracy of measurement. This interest places new demands on our in-line metrology systems as well as the supporting metrology for verification. This also puts a burden on the users and suppliers of new measurement tools, which both challenge and complement existing manufacturing metrology. The metrology community needs to respond to these challenges by using new methods to assess the fab metrologies. An important part of this assessment process is the ability to obtain accepted reference measurements as a way of determining the accuracy and Total Measurement Uncertainty (TMU) of an in-line critical dimension (CD). In this paper, CD can mean any critical dimension including, for example, such measures as feature height or sidewall angle. This paper describes the trade-offs of in-line metrology systems as well as the limitations of Reference Measurement Systems (RMS). Many factors influence each application such as feature shape, material properties, proximity, sampling, and critical dimension. These factors, along with the metrology probe size, interaction volume, and probe type such as e-beam, optical beam, and mechanical probe, are considered. As the size of features shrinks below 100nm some of the stalwarts of reference metrology come into question, such as the electrically determined transistor gate length. The concept of the RMS is expanded to show how multiple metrologies are needed to achieve the right balance of accuracy and sampling. This is also demonstrated for manufacturing metrology. Various comparisons of CDSEM, scatterometry, AFM, cross section SEM, electrically determined CDs, and TEM are shown. An example is given which demonstrates the importance in obtaining TMU by balancing accuracy and precision for selecting manufacturing measurement strategy and optimizing manufacturing metrology. It is also demonstrated how the necessary supporting metrology will bring together formerly unlinked technology fields requiring new measurement science. The emphasis on accuracy will increase the importance and role of NIST and similar metrology organizations in supporting the semiconductor industry in this effort.

Overlay metrology for double patterning processes

NASA Astrophysics Data System (ADS)

Leray, Philippe; Cheng, Shaunee; Laidler, David; Kandel, Daniel; Adel, Mike; Dinu, Berta; Polli, Marco; Vasconi, Mauro; Salski, Bartlomiej

2009-03-01

The double patterning (DPT) process is foreseen by the industry to be the main solution for the 32 nm technology node and even beyond. Meanwhile process compatibility has to be maintained and the performance of overlay metrology has to improve. To achieve this for Image Based Overlay (IBO), usually the optics of overlay tools are improved. It was also demonstrated that these requirements are achievable with a Diffraction Based Overlay (DBO) technique named SCOLTM [1]. In addition, we believe that overlay measurements with respect to a reference grid are required to achieve the required overlay control [2]. This induces at least a three-fold increase in the number of measurements (2 for double patterned layers to the reference grid and 1 between the double patterned layers). The requirements of process compatibility, enhanced performance and large number of measurements make the choice of overlay metrology for DPT very challenging. In this work we use different flavors of the standard overlay metrology technique (IBO) as well as the new technique (SCOL) to address these three requirements. The compatibility of the corresponding overlay targets with double patterning processes (Litho-Etch-Litho-Etch (LELE); Litho-Freeze-Litho-Etch (LFLE), Spacer defined) is tested. The process impact on different target types is discussed (CD bias LELE, Contrast for LFLE). We compare the standard imaging overlay metrology with non-standard imaging techniques dedicated to double patterning processes (multilayer imaging targets allowing one overlay target instead of three, very small imaging targets). In addition to standard designs already discussed [1], we investigate SCOL target designs specific to double patterning processes. The feedback to the scanner is determined using the different techniques. The final overlay results obtained are compared accordingly. We conclude with the pros and cons of each technique and suggest the optimal metrology strategy for overlay control in double patterning processes.

Integrated scatterometry for tight overlay and CD control to enable 20-nm node wafer manufacturing.

NASA Astrophysics Data System (ADS)

Benschop, Jos; Engelen, Andre; Cramer, Hugo; Kubis, Michael; Hinnen, Paul; van der Laan, Hans; Bhattacharyya, Kaustuve; Mulkens, Jan

2013-04-01

The overlay, CDU and focus requirements for the 20nm node can only be met using a holistic lithography approach whereby full use is made of high-order, field-by-field, scanner correction capabilities. An essential element in this approach is a fast, precise and accurate in-line metrology sensor, capable to measure on product. The capabilities of the metrology sensor as well as the impact on overlay, CD and focus will be shared in this paper.

YieldStar based reticle 3D measurements and its application

NASA Astrophysics Data System (ADS)

Vaenkatesan, Vidya; Finders, Jo; ten Berge, Peter; Plug, Reinder; Sijben, Anko; Schellekens, Twan; Dillen, Harm; Pocobiej, Wojciech; Jorge, Vasco G.; van Dijck, Jurgen

2016-09-01

YieldStar (YS) is an established ASML-built scatterometer that is capable of measuring wafer Critical Dimension (CD), Overlay and Focus. In a recent work, the application range of YS was extended to measure 3D CD patterns on a reticle (pattern CD, height, Side Wall Angle-SWA). The primary motivation for this study came from imaging studies that indicated a need for measuring and controlling reticle 3D topography. CD scanning electron microscope (CD-SEM), Atomic force microscope (AFM), 3D multiple detector SEM (3D-SEM) are the preferred tools for reticle metrology. While these tools serve the industry well, the current research to the impact of reticle 3D involves extensive costs, logistic challenges and increased reticle lead time. YS provides an attractive alternative as it can measure pattern CD, SWA and height in a single measurement and at high throughput. This work demonstrates the capability of YS as a reticle metrology tool.

ArF scanner performance improvement by using track integrated CD optimization

NASA Astrophysics Data System (ADS)

Huang, Jacky; Yu, Shinn-Sheng; Ke, Chih-Ming; Wu, Timothy; Wang, Yu-Hsi; Gau, Tsai-Sheng; Wang, Dennis; Li, Allen; Yang, Wenge; Kaoru, Araki

2006-03-01

In advanced semiconductor processing, shrinking CD is one of the main objectives when moving to the next generation technology. Improving CD uniformity (CDU) with shrinking CD is one of the biggest challenges. From ArF lithography CD error budget analysis, PEB (post exposure bake) contributes more than 40% CD variations. It turns out that hot plate performance such as CD matching and within-plate temperature control play key roles in litho cell wafer per hour (WPH). Traditionally wired or wireless thermal sensor wafers were used to match and optimize hot plates. However, sensor-to-sensor matching and sensor data quality vs. sensor lifetime or sensor thermal history are still unknown. These concerns make sensor wafers more suitable for coarse mean-temperature adjustment. For precise temperature adjustment, especially within-hot-plate temperature uniformity, using CD instead of sensor wafer temperature is a better and more straightforward metrology to calibrate hot plates. In this study, we evaluated TEL clean track integrated optical CD metrology (IM) combined with TEL CD Optimizer (CDO) software to improve 193-nm resist within-wafer and wafer-to-wafer CD uniformity. Within-wafer CD uniformity is mainly affected by the temperature non-uniformity on the PEB hot plate. Based on CD and PEB sensitivity of photo resists, a physical model has been established to control the CD uniformity through fine-tuning PEB temperature settings. CD data collected by track integrated CD metrology was fed into this model, and the adjustment of PEB setting was calculated and executed through track internal APC system. This auto measurement, auto feed forward, auto calibration and auto adjustment system can reduce the engineer key-in error and improve the hot plate calibration cycle time. And this PEB auto calibration system can easily bring hot-plate-to-hot-plate CD matching to within 0.5nm and within-wafer CDU (3σ) to less than 1.5nm.

DFM flow by using combination between design based metrology system and model based verification at sub-50nm memory device

NASA Astrophysics Data System (ADS)

Kim, Cheol-kyun; Kim, Jungchan; Choi, Jaeseung; Yang, Hyunjo; Yim, Donggyu; Kim, Jinwoong

2007-03-01

As the minimum transistor length is getting smaller, the variation and uniformity of transistor length seriously effect device performance. So, the importance of optical proximity effects correction (OPC) and resolution enhancement technology (RET) cannot be overemphasized. However, OPC process is regarded by some as a necessary evil in device performance. In fact, every group which includes process and design, are interested in whole chip CD variation trend and CD uniformity, which represent real wafer. Recently, design based metrology systems are capable of detecting difference between data base to wafer SEM image. Design based metrology systems are able to extract information of whole chip CD variation. According to the results, OPC abnormality was identified and design feedback items are also disclosed. The other approaches are accomplished on EDA companies, like model based OPC verifications. Model based verification will be done for full chip area by using well-calibrated model. The object of model based verification is the prediction of potential weak point on wafer and fast feed back to OPC and design before reticle fabrication. In order to achieve robust design and sufficient device margin, appropriate combination between design based metrology system and model based verification tools is very important. Therefore, we evaluated design based metrology system and matched model based verification system for optimum combination between two systems. In our study, huge amount of data from wafer results are classified and analyzed by statistical method and classified by OPC feedback and design feedback items. Additionally, novel DFM flow would be proposed by using combination of design based metrology and model based verification tools.

Solving next generation (1x node) metrology challenges using advanced CDSEM capabilities: tilt, high energy and backscatter imaging

NASA Astrophysics Data System (ADS)

Zhang, Xiaoxiao; Snow, Patrick W.; Vaid, Alok; Solecky, Eric; Zhou, Hua; Ge, Zhenhua; Yasharzade, Shay; Shoval, Ori; Adan, Ofer; Schwarzband, Ishai; Bar-Zvi, Maayan

2015-03-01

Traditional metrology solutions are facing a range of challenges at the 1X node such as three dimensional (3D) measurement capabilities, shrinking overlay and critical dimension (CD) error budgets driven by multi-patterning and via in trench CD measurements. Hybrid metrology offers promising new capabilities to address some of these challenges but it will take some time before fully realized. This paper explores new capabilities currently offered on the in-line Critical Dimension Scanning Electron Microscope (CD-SEM) to address these challenges and enable the CD-SEM to move beyond measuring bottom CD using top down imaging. Device performance is strongly correlated with Fin geometry causing an urgent need for 3D measurements. New beam tilting capabilities enhance the ability to make 3D measurements in the front-end-of-line (FEOL) of the metal gate FinFET process in manufacturing. We explore these new capabilities for measuring Fin height and build upon the work communicated last year at SPIE1. Furthermore, we extend the application of the tilt beam to the back-end-of-line (BEOL) trench depth measurement and demonstrate its capability in production targeting replacement of the existing Atomic Force Microscope (AFM) measurements by including the height measurement in the existing CDSEM recipe to reduce fab cycle time. In the BEOL, another increasingly challenging measurement for the traditional CD-SEM is the bottom CD of the self-aligned via (SAV) in a trench first via last (TFVL) process. Due to the extremely high aspect ratio of the structure secondary electron (SE) collection from the via bottom is significantly reduced requiring the use of backscatter electrons (BSE) to increase the relevant image quality. Even with this solution, the resulting images are difficult to measure with advanced technology nodes. We explore new methods to increase measurement robustness and combine this with novel segmentation-based measurement algorithm generated specifically for BSE images. The results will be contrasted with data from previously used methods to quantify the improvement. We also compare the results to electrical test data to evaluate and quantify the measurement performance improvements. Lastly, according to International Technology Roadmap for Semiconductors (ITRS) from 2013, the overlay 3 sigma requirement will be 3.3 nm in 2015 and 2.9 nm in 2016. Advanced lithography requires overlay measurement in die on features resembling the device geometry. However, current optical overlay measurement is performed in the scribe line on large targets due to optical diffraction limit. In some cases, this limits the usefulness of the measurement since it does not represent the true behavior of the device. We explore using high voltage imaging to help address this urgent need. Novel CD-SEM based overlay targets that optimize the restrictions of process geometry and SEM technique were designed and spread out across the die. Measurements are done on these new targets both after photolithography and etch. Correlation is drawn between the two measurements. These results will also be compared to conventional optical overlay measurement approaches and we will discuss the possibility of using this capability in high volume manufacturing.

Holistic approach for overlay and edge placement error to meet the 5nm technology node requirements

NASA Astrophysics Data System (ADS)

Mulkens, Jan; Slachter, Bram; Kubis, Michael; Tel, Wim; Hinnen, Paul; Maslow, Mark; Dillen, Harm; Ma, Eric; Chou, Kevin; Liu, Xuedong; Ren, Weiming; Hu, Xuerang; Wang, Fei; Liu, Kevin

2018-03-01

In this paper, we discuss the metrology methods and error budget that describe the edge placement error (EPE). EPE quantifies the pattern fidelity of a device structure made in a multi-patterning scheme. Here the pattern is the result of a sequence of lithography and etching steps, and consequently the contour of the final pattern contains error sources of the different process steps. EPE is computed by combining optical and ebeam metrology data. We show that high NA optical scatterometer can be used to densely measure in device CD and overlay errors. Large field e-beam system enables massive CD metrology which is used to characterize the local CD error. Local CD distribution needs to be characterized beyond 6 sigma, and requires high throughput e-beam system. We present in this paper the first images of a multi-beam e-beam inspection system. We discuss our holistic patterning optimization approach to understand and minimize the EPE of the final pattern. As a use case, we evaluated a 5-nm logic patterning process based on Self-Aligned-QuadruplePatterning (SAQP) using ArF lithography, combined with line cut exposures using EUV lithography.

Automated hotspot analysis with aerial image CD metrology for advanced logic devices

NASA Astrophysics Data System (ADS)

Buttgereit, Ute; Trautzsch, Thomas; Kim, Min-ho; Seo, Jung-Uk; Yoon, Young-Keun; Han, Hak-Seung; Chung, Dong Hoon; Jeon, Chan-Uk; Meyers, Gary

2014-09-01

Continuously shrinking designs by further extension of 193nm technology lead to a much higher probability of hotspots especially for the manufacturing of advanced logic devices. The CD of these potential hotspots needs to be precisely controlled and measured on the mask. On top of that, the feature complexity increases due to high OPC load in the logic mask design which is an additional challenge for CD metrology. Therefore the hotspot measurements have been performed on WLCD from ZEISS, which provides the benefit of reduced complexity by measuring the CD in the aerial image and qualifying the printing relevant CD. This is especially of advantage for complex 2D feature measurements. Additionally, the data preparation for CD measurement becomes more critical due to the larger amount of CD measurements and the increasing feature diversity. For the data preparation this means to identify these hotspots and mark them automatically with the correct marker required to make the feature specific CD measurement successful. Currently available methods can address generic pattern but cannot deal with the pattern diversity of the hotspots. The paper will explore a method how to overcome those limitations and to enhance the time-to-result in the marking process dramatically. For the marking process the Synopsys WLCD Output Module was utilized, which is an interface between the CATS mask data prep software and the WLCD metrology tool. It translates the CATS marking directly into an executable WLCD measurement job including CD analysis. The paper will describe the utilized method and flow for the hotspot measurement. Additionally, the achieved results on hotspot measurements utilizing this method will be presented.

A scatterometry based CD metrology solution for advanced nodes, including capability of handling birefringent layers with uniaxial anisotropy

NASA Astrophysics Data System (ADS)

Ke, Chih-Ming; Hu, Jimmy; Wang, Willie; Huang, Jacky; Chung, H. L.; Liang, C. R.; Shih, Victor; Liu, H. H.; Lee, H. J.; Lin, John; Fan, Y. D.; Yen, Tony; Wright, Noelle; Alvarez Sanchez, Ruben; Coene, Wim; Noot, Marc; Yuan, Kiwi; Wang, Vivien; Bhattacharyya, Kaustuve; van der Mast, Karel

2009-03-01

A brand new CD metrology technique that can address the need for accuracy, precision and speed in near future lithography is probably one of the most challenging items. CDSEMs have served this need for a long time, however, a change of or an addition to this traditional approach is inevitable as the increase in the need for better precision (tight CDU budget) and speed (driven by the demand for increase in sampling) continues to drive the need for advanced nodes. The success of CD measurement with scatterometry remains in the capability to model the resist grating, such as, CD and shape (side wall angle), as well as the under-lying layers (thickness and material property). Things are relatively easier for the cases with isotropic under-lying layers (that consists of single refractive or absorption indices). However, a real challenge to such a technique becomes evident when one or more of the under-lying layers are anisotropic. In this technical presentation the authors would like to evaluate such CD reconstruction technology, a new scatterometry based platform under development at ASML, which can handle bi-refringent non-patterned layers with uniaxial anisotropy in the underlying stack. In the RCWA code for the bi-refringent case, the elegant formalism of the enhanced transmittance matrix can still be used. In this paper, measurement methods and data will be discussed from several complex production stacks (layers). With inclusion of the bi-refringent modeling, the in-plane and perpendicular n and k values can be treated as floating parameters for the bi-refringent layer, so that very robust CD-reconstruction is achieved with low reconstruction residuals. As a function of position over the wafer, significant variations of the perpendicular n and k values are observed, with a typical radial fingerprint on the wafer, whereas the variations in the in-plane n and k values are seen to be considerably lower.

Investigation of phase distribution using Phame® in-die phase measurements

NASA Astrophysics Data System (ADS)

Buttgereit, Ute; Perlitz, Sascha

2009-03-01

As lithography mask processes move toward 45nm and 32nm node, mask complexity increases steadily, mask specifications tighten and process control becomes extremely important. Driven by this fact the requirements for metrology tools increase as well. Efforts in metrology have been focused on accurately measuring CD linearity and uniformity across the mask, and accurately measuring phase variation on Alternating/Attenuated PSM and transmission for Attenuated PSM. CD control on photo masks is usually done through the following processes: exposure dose/focus change, resist develop and dry etch. The key requirement is to maintain correct CD linearity and uniformity across the mask. For PSM specifically, the effect of CD uniformity for both Alternating PSM and Attenuated PSM and etch depth for Alternating PSM becomes also important. So far phase measurement has been limited to either measuring large-feature phase using interferometer-based metrology tools or measuring etch depth using AFM and converting etch depth into phase under the assumption that trench profile and optical properties of the layers remain constant. However recent investigations show that the trench profile and optical property of layers impact the phase. This effect is getting larger for smaller CD's. The currently used phase measurement methods run into limitations because they are not able to capture 3D mask effects, diffraction limitations or polarization effects. The new phase metrology system - Phame(R) developed by Carl Zeiss SMS overcomes those limitations and enables laterally resolved phase measurement in any kind of production feature on the mask. The resolution of the system goes down to 120nm half pitch at mask level. We will report on tool performance data with respect to static and dynamic phase repeatability focusing on Alternating PSM. Furthermore the phase metrology system was used to investigate mask process signatures on Alternating PSM in order to further improve the overall PSM process performance. Especially global loading effects caused by the pattern density and micro loading effects caused by the feature size itself have been evaluated using the capability of measuring phase in the small production features. The results of this study will be reported in this paper.

Improving Metrological Reliability of Information-Measuring Systems Using Mathematical Modeling of Their Metrological Characteristics

NASA Astrophysics Data System (ADS)

Kurnosov, R. Yu; Chernyshova, T. I.; Chernyshov, V. N.

2018-05-01

The algorithms for improving the metrological reliability of analogue blocks of measuring channels and information-measuring systems are developed. The proposed algorithms ensure the optimum values of their metrological reliability indices for a given analogue circuit block solution.

Evaluation of a new photomask CD metrology tool

NASA Astrophysics Data System (ADS)

Dubuque, Leonard F.; Doe, Nicholas G.; St. Cin, Patrick

1996-12-01

In the integrated circuit (IC) photomask industry today, dense IC patterns, sub-micron critical dimensions (CD), and narrow tolerances for 64 M technologies and beyond are driving increased demands to minimize and characterize all components of photomask CD variation. This places strict requirements on photomask CD metrology in order to accurately characterize the mask CD error distribution. According to the gauge-maker's rule, measurement error must not exceed 30% of the tolerance on the product dimension measured or the gauge is not considered capable. The traditional single point repeatability tests are a poor measure of overall measurement system error in a dynamic, leading-edge technology environment. In such an environment, measurements may be taken at different points in the field- of-view due to stage in-accuracy, pattern recognition requirements, and throughput considerations. With this in mind, a set of experiments were designed to characterize thoroughly the metrology tool's repeatability and systematic error. Original experiments provided inconclusive results and had to be extended to obtain a full characterization of the system. Tests demonstrated a performance of better than 15 nm total CD error. Using this test as a tool for further development, the authors were able to determine the effects of various system components and measure the improvement with changes in optics, electronics, and software. Optimization of the optical path, electronics, and system software has yielded a new instrument with a total system error of better than 8 nm. Good collaboration between the photomask manufacturer and the equipment supplier has led to a realistic test of system performance and an improved CD measurement instrument.

Line-width roughness of advanced semiconductor features by using FIB and planar-TEM as reference metrology

NASA Astrophysics Data System (ADS)

Takamasu, Kiyoshi; Takahashi, Satoru; Kawada, Hiroki; Ikota, Masami

2018-03-01

LER (Line Edge Roughness) and LWR (Line Width Roughness) of the semiconductor device are an important evaluation scale of the performance of the device. Conventionally, LER and LWR is evaluated from CD-SEM (Critical Dimension Scanning Electron Microscope) images. However, CD-SEM measurement has a problem that high frequency random noise is large, and resolution is not sufficiently high. For random noise of CD-SEM measurement, some techniques are proposed. In these methods, it is necessary to set parameters for model and processing, and it is necessary to verify the correctness of these parameters using reference metrology. We have already proposed a novel reference metrology using FIB (Focused Ion Beam) process and planar-TEM (Transmission Electron Microscope) method. In this study, we applied the proposed method to three new samples such as SAQP (Self-Aligned Quadruple Patterning) FinFET device, EUV (Extreme Ultraviolet Lithography) conventional resist, and EUV new material resist. LWR and PSD (Power Spectral Density) of LWR are calculated from the edge positions on planar-TEM images. We confirmed that LWR and PSD of LWR can be measured with high accuracy and evaluated the difference by the proposed method. Furthermore, from comparisons with PSD of the same sample by CD-SEM, the validity of measurement of PSD and LWR by CD-SEM can be verified.

How to obtain accurate resist simulations in very low-k1 era?

NASA Astrophysics Data System (ADS)

Chiou, Tsann-Bim; Park, Chan-Ha; Choi, Jae-Seung; Min, Young-Hong; Hansen, Steve; Tseng, Shih-En; Chen, Alek C.; Yim, Donggyu

2006-03-01

A procedure for calibrating a resist model iteratively adjusts appropriate parameters until the simulations of the model match the experimental data. The tunable parameters may include the shape of the illuminator, the geometry and transmittance/phase of the mask, light source and scanner-related parameters that affect imaging quality, resist process control and most importantly the physical/chemical factors in the resist model. The resist model can be accurately calibrated by measuring critical dimensions (CD) of a focus-exposure matrix (FEM) and the technique has been demonstrated to be very successful in predicting lithographic performance. However, resist model calibration is more challenging in the low k1 (<0.3) regime because numerous uncertainties, such as mask and resist CD metrology errors, are becoming too large to be ignored. This study demonstrates a resist model calibration procedure for a 0.29 k1 process using a 6% halftone mask containing 2D brickwall patterns. The influence of different scanning electron microscopes (SEM) and their wafer metrology signal analysis algorithms on the accuracy of the resist model is evaluated. As an example of the metrology issue of the resist pattern, the treatment of a sidewall angle is demonstrated for the resist line ends where the contrast is relatively low. Additionally, the mask optical proximity correction (OPC) and corner rounding are considered in the calibration procedure that is based on captured SEM images. Accordingly, the average root-mean-square (RMS) error, which is the difference between simulated and experimental CDs, can be improved by considering the metrological issues. Moreover, a weighting method and a measured CD tolerance are proposed to handle the different CD variations of the various edge points of the wafer resist pattern. After the weighting method is implemented and the CD selection criteria applied, the RMS error can be further suppressed. Therefore, the resist CD and process window can be confidently evaluated using the accurately calibrated resist model. One of the examples simulates the sensitivity of the mask pattern error, which is helpful to specify the mask CD control.

Joint Research on Scatterometry and AFM Wafer Metrology

NASA Astrophysics Data System (ADS)

Bodermann, Bernd; Buhr, Egbert; Danzebrink, Hans-Ulrich; Bär, Markus; Scholze, Frank; Krumrey, Michael; Wurm, Matthias; Klapetek, Petr; Hansen, Poul-Erik; Korpelainen, Virpi; van Veghel, Marijn; Yacoot, Andrew; Siitonen, Samuli; El Gawhary, Omar; Burger, Sven; Saastamoinen, Toni

2011-11-01

Supported by the European Commission and EURAMET, a consortium of 10 participants from national metrology institutes, universities and companies has started a joint research project with the aim of overcoming current challenges in optical scatterometry for traceable linewidth metrology. Both experimental and modelling methods will be enhanced and different methods will be compared with each other and with specially adapted atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurement systems in measurement comparisons. Additionally novel methods for sophisticated data analysis will be developed and investigated to reach significant reductions of the measurement uncertainties in critical dimension (CD) metrology. One final goal will be the realisation of a wafer based reference standard material for calibration of scatterometers.

3D-profile measurement of advanced semiconductor features by using FIB as reference metrology

NASA Astrophysics Data System (ADS)

Takamasu, Kiyoshi; Iwaki, Yuuki; Takahashi, Satoru; Kawada, Hiroki; Ikota, Masami

2017-03-01

A novel method of sub-nanometer uncertainty for the 3D-profile measurement and LWR (Line Width Roughness) measurement by using FIB (Focused Ion Beam) processing, and TEM (Transmission Electron Microscope) and CD-SEM (Critical Dimension Scanning Electron Microscope) images measurement is proposed to standardize 3D-profile measurement through reference metrology. In this article, we apply the methodology to line profile measurements and roughness measurement of advanced FinFET (Fin-shaped Field-Effect Transistor) features. The FinFET features are horizontally sliced as a thin specimen by FIB micro sampling system. Horizontally images of the specimens are obtained then by a planar TEM. LWR is calculated from the edges positions on TEM images. Moreover, we already have demonstrated the novel on-wafer 3D-profile metrology as "FIB-to-CDSEM method" with FIB slope cut and CD-SEM measuring. Using the method, a few micrometers wide on a wafer is coated and cut by 45-degree slope using FIB tool. Then, the wafer is transferred to CD-SEM to measure the cross section image by top down CD-SEM measurement. We applied FIB-to-CDSEM method to a CMOS image sensor feature. The 45-degree slope cut surface is observed using AFM. The surface profile of slope cut surface and line profiles are analyzed for improving the accuracy of FIB-to-CDSEM method.

The impact of 14-nm photomask uncertainties on computational lithography solutions

NASA Astrophysics Data System (ADS)

Sturtevant, John; Tejnil, Edita; Lin, Tim; Schultze, Steffen; Buck, Peter; Kalk, Franklin; Nakagawa, Kent; Ning, Guoxiang; Ackmann, Paul; Gans, Fritz; Buergel, Christian

2013-04-01

Computational lithography solutions rely upon accurate process models to faithfully represent the imaging system output for a defined set of process and design inputs. These models, which must balance accuracy demands with simulation runtime boundary conditions, rely upon the accurate representation of multiple parameters associated with the scanner and the photomask. While certain system input variables, such as scanner numerical aperture, can be empirically tuned to wafer CD data over a small range around the presumed set point, it can be dangerous to do so since CD errors can alias across multiple input variables. Therefore, many input variables for simulation are based upon designed or recipe-requested values or independent measurements. It is known, however, that certain measurement methodologies, while precise, can have significant inaccuracies. Additionally, there are known errors associated with the representation of certain system parameters. With shrinking total CD control budgets, appropriate accounting for all sources of error becomes more important, and the cumulative consequence of input errors to the computational lithography model can become significant. In this work, we examine with a simulation sensitivity study, the impact of errors in the representation of photomask properties including CD bias, corner rounding, refractive index, thickness, and sidewall angle. The factors that are most critical to be accurately represented in the model are cataloged. CD Bias values are based on state of the art mask manufacturing data and other variables changes are speculated, highlighting the need for improved metrology and awareness.

Mycotoxin metrology: Gravimetric production of zearalenone calibration solution

NASA Astrophysics Data System (ADS)

Rego, E. C. P.; Simon, M. E.; Li, Xiuqin; Li, Xiaomin; Daireaux, A.; Choteau, T.; Westwood, S.; Josephs, R. D.; Wielgosz, R. I.; Cunha, V. S.

2018-03-01

Food safety is a major concern for countries developing metrology and quality assurance systems, including the contamination of food and feed by mycotoxins. To improve the mycotoxin analysis and ensure the metrological traceability, CRM of calibration solution should be used. The production of certified mycotoxin solutions is a major challenge due to the limited amount of standard for conducting a proper purity study and due to the cost of standards. The CBKT project was started at BIPM and Inmetro produced gravimetrically one batch of zearelenone in acetronitrile (14.708 ± 0.016 μg/g, k=2) and conducted homogeneity, stability and value assignment studies.

Metrological traceability of holmium oxide solution

NASA Astrophysics Data System (ADS)

Gonçalves, D. E. F.; Gomes, J. F. S.; Alvarenga, A. P. D.; Borges, P. P.; Araujo, T. O.

2018-03-01

Holmium oxide solution was prepared as a candidate of certified reference material for spectrophotometer wavelength scale calibration. Here is presented the necessary steps for evaluation of the uncertainty and the establishment of metrological traceability for the production of this material. Preliminary results from the first produced batch are shown.

Advanced in-line metrology strategy for self-aligned quadruple patterning

NASA Astrophysics Data System (ADS)

Chao, Robin; Breton, Mary; L'herron, Benoit; Mendoza, Brock; Muthinti, Raja; Nelson, Florence; De La Pena, Abraham; Le, Fee li; Miller, Eric; Sieg, Stuart; Demarest, James; Gin, Peter; Wormington, Matthew; Cepler, Aron; Bozdog, Cornel; Sendelbach, Matthew; Wolfling, Shay; Cardinal, Tom; Kanakasabapathy, Sivananda; Gaudiello, John; Felix, Nelson

2016-03-01

Self-Aligned Quadruple Patterning (SAQP) is a promising technique extending the 193-nm lithography to manufacture structures that are 20nm half pitch or smaller. This process adopts multiple sidewall spacer image transfers to split a rather relaxed design into a quarter of its original pitch. Due to the number of multiple process steps required for the pitch splitting in SAQP, the process error propagates through each deposition and etch, and accumulates at the final step into structure variations, such as pitch walk and poor critical dimension uniformity (CDU). They can further affect the downstream processes and lower the yield. The impact of this error propagation becomes significant for advanced technology nodes when the process specifications of device design CD requirements are at nanometer scale. Therefore, semiconductor manufacturing demands strict in-line process control to ensure a high process yield and improved performance, which must rely on precise measurements to enable corrective actions and quick decision making for process development. This work aims to provide a comprehensive metrology solution for SAQP. During SAQP process development, the challenges in conventional in-line metrology techniques start to surface. For instance, critical-dimension scanning electron microscopy (CDSEM) is commonly the first choice for CD and pitch variation control. However, it is found that the high aspect ratio at mandrel level processes and the trench variations after etch prevent the tool from extracting the true bottom edges of the structure in order to report the position shift. On the other hand, while the complex shape and variations can be captured with scatterometry, or optical CD (OCD), the asymmetric features, such as pitch walk, show low sensitivity with strong correlations in scatterometry. X-ray diffraction (XRD) is known to provide useful direct measurements of the pitch walk in crystalline arrays, yet the data analysis is influenced by the incoming geometry and must be used carefully. A successful implementation of SAQP process control for yield improvement requires the metrology issues to be addressed. By optimizing the measurement parameters and beam configurations, CDSEM measurements distinguish each of the spaces corresponding to the upstream mandrel processes and report their CDs separately to feed back to the process team for the next development cycle. We also utilize the unique capability in scatterometry to measure the structure details in-line and implement a "predictive" process control, which shows a good correlation between the "predictive" measurement and the cross-sections from our design of experiments (DOE). The ability to measure the pitch walk in scatterometry was also demonstrated. This work also explored the frontier of in-line XRD capability by enabling an automatic RSM fitting on tool to output pitch walk values. With these advances in metrology development, we are able to demonstrate the impacts of in-line monitoring in the SAQP process, to shorten the patterning development learning cycle to improve the yield.

Study of shape evaluation for mask and silicon using large field of view

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Shinoda, Shinichi; Toyoda, Yasutaka

2010-09-01

We have developed a highly integrated method of mask and silicon metrology. The aim of this integration is evaluating the performance of the silicon corresponding to Hotspot on a mask. It can use the mask shape of a large field, besides. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and mask manufacture, and this has a big impact on the semiconductor market that centers on the mask business. As an optimal solution to these issues, we provide a DFM solution that extracts 2-dimensional data for a more realistic and error-free simulation by reproducing accurately the contour of the actual mask, in addition to the simulation results from the mask data. On the other hand, there is roughness in the silicon form made from a mass-production line. Moreover, there is variation in the silicon form. For this reason, quantification of silicon form is important, in order to estimate the performance of a pattern. In order to quantify, the same form is equalized in two dimensions. And the method of evaluating based on the form is popular. In this study, we conducted experiments for averaging method of the pattern (Measurement Based Contouring) as two-dimensional mask and silicon evaluation technique. That is, observation of the identical position of a mask and a silicon was considered. The result proved its detection accuracy and reliability of variability on two-dimensional pattern (mask and silicon) and is adaptable to following fields of mask quality management. •Discrimination of nuisance defects for fine pattern. •Determination of two-dimensional variability of pattern. •Verification of the performance of the pattern of various kinds of Hotspots. In this report, we introduce the experimental results and the application. We expect that the mask measurement and the shape control on mask production will make a huge contribution to mask yield-enhancement and that the DFM solution for mask quality control process will become much more important technology than ever. It is very important to observe the form of the same location of Design, Mask, and Silicon in such a viewpoint. And we report it about algorithm of the image composition in Large Field.

A new approach to pattern metrology

NASA Astrophysics Data System (ADS)

Ausschnitt, Christopher P.

2004-05-01

We describe an approach to pattern metrology that enables the simultaneous determination of critical dimensions, overlay and film thickness. A single optical system captures nonzero- and zero-order diffracted signals from illuminated grating targets, as well as unpatterned regions of the surrounding substrate. Differential targets provide in situ dimensional calibration. CD target signals are analyzed to determine average dimension, profile attributes, and effective dose and defocus. In turn, effective dose and defocus determines all CDs pre-correlated to the dose and focus settings of the exposure tool. Overlay target signals are analyzed to determine the relative reflectivity of the layer pair and the overlay error between them. Compared to commercially available pattern metrology (SEM, optical microscopy, AFM, scatterometry and schnitzlometry), our approach promises improved signal-to-noise, higher throughput and smaller targets. We have dubbed this optical chimera MOXIE (Metrology Of eXtremely Irrational Exuberance).

Optics for Processes, Products and Metrology

NASA Astrophysics Data System (ADS)

Mather, George

1999-04-01

Optical physics has a variety of applications in industry, including process inspection, coatings development, vision instrumentation, spectroscopy, and many others. Optics has been used extensively in the design of solar energy collection systems and coatings, for example. Also, with the availability of good CCD cameras and fast computers, it has become possible to develop real-time inspection and metrology devices that can accommodate the high throughputs encountered in modern production processes. More recently, developments in moiré interferometry show great promise for applications in the basic metals and electronics industries. The talk will illustrate applications of optics by discussing process inspection techniques for defect detection, part dimensioning, birefringence measurement, and the analysis of optical coatings in the automotive, glass, and optical disc industries. In particular, examples of optical techniques for the quality control of CD-R, MO, and CD-RW discs will be presented. In addition, the application of optical concepts to solar energy collector design and to metrology by moiré techniques will be discussed. Finally, some of the modern techniques and instruments used for qualitative and quantitative material analysis will be presented.

The European Comparison of Absolute Gravimeters 2011 (ECAG-2011) in Walferdange, Luxembourg: results and recommendations

NASA Astrophysics Data System (ADS)

Francis, Olivier; Baumann, Henri; Volarik, Tomas; Rothleitner, Christian; Klein, Gilbert; Seil, Marc; Dando, Nicolas; Tracey, Ray; Ullrich, Christian; Castelein, Stefaan; Hua, Hu; Kang, Wu; Chongyang, Shen; Songbo, Xuan; Hongbo, Tan; Zhengyuan, Li; Pálinkás, Vojtech; Kostelecký, Jakub; Mäkinen, Jaakko; Näränen, Jyri; Merlet, Sébastien; Farah, Tristan; Guerlin, Christine; Pereira Dos Santos, Franck; Le Moigne, Nicolas; Champollion, Cédric; Deville, Sabrina; Timmen, Ludger; Falk, Reinhard; Wilmes, Herbert; Iacovone, Domenico; Baccaro, Francesco; Germak, Alessandro; Biolcati, Emanuele; Krynski, Jan; Sekowski, Marcin; Olszak, Tomasz; Pachuta, Andrzej; Agren, Jonas; Engfeldt, Andreas; Reudink, René; Inacio, Pedro; McLaughlin, Daniel; Shannon, Geoff; Eckl, Marc; Wilkins, Tim; van Westrum, Derek; Billson, Ryan

2013-06-01

We present the results of the third European Comparison of Absolute Gravimeters held in Walferdange, Grand Duchy of Luxembourg, in November 2011. Twenty-two gravimeters from both metrological and non-metrological institutes are compared. For the first time, corrections for the laser beam diffraction and the self-attraction of the gravimeters are implemented. The gravity observations are also corrected for geophysical gravity changes that occurred during the comparison using the observations of a superconducting gravimeter. We show that these corrections improve the degree of equivalence between the gravimeters. We present the results for two different combinations of data. In the first one, we use only the observations from the metrological institutes. In the second solution, we include all the data from both metrological and non-metrological institutes. Those solutions are then compared with the official result of the comparison published previously and based on the observations of the metrological institutes and the gravity differences at the different sites as measured by non-metrological institutes. Overall, the absolute gravity meters agree with one another with a standard deviation of 3.1 µGal. Finally, the results of this comparison are linked to previous ones. We conclude with some important recommendations for future comparisons.

Evaluating diffraction based overlay metrology for double patterning technologies

NASA Astrophysics Data System (ADS)

Saravanan, Chandra Saru; Liu, Yongdong; Dasari, Prasad; Kritsun, Oleg; Volkman, Catherine; Acheta, Alden; La Fontaine, Bruno

2008-03-01

Demanding sub-45 nm node lithographic methodologies such as double patterning (DPT) pose significant challenges for overlay metrology. In this paper, we investigate scatterometry methods as an alternative approach to meet these stringent new metrology requirements. We used a spectroscopic diffraction-based overlay (DBO) measurement technique in which registration errors are extracted from specially designed diffraction targets for double patterning. The results of overlay measurements are compared to traditional bar-in-bar targets. A comparison between DBO measurements and CD-SEM measurements is done to show the correlation between the two approaches. We discuss the total measurement uncertainty (TMU) requirements for sub-45 nm nodes and compare TMU from the different overlay approaches.

Addressing FinFET metrology challenges in 1X node using tilt-beam CD-SEM

NASA Astrophysics Data System (ADS)

Zhang, Xiaoxiao; Zhou, Hua; Ge, Zhenhua; Vaid, Alok; Konduparthi, Deepasree; Osorio, Carmen; Ventola, Stefano; Meir, Roi; Shoval, Ori; Kris, Roman; Adan, Ofer; Bar-Zvi, Maayan

2014-04-01

At 1X node, 3D FinFETS raise a number of new metrology challenges. Gate height and fin height are two of the most important parameters for process control. At present there is a metrology gap in inline in-die measurement of these parameters. In order to fill this metrology gap, in-column beam tilt has been developed and implemented on Applied Materials V4i+ top-down CD-SEM for height measurement. A low tilt (5°) beam and a high tilt (14°) beam have been calibrated to obtain two sets of images providing measurement of sidewall edge width to calculate height in the host. Evaluations are done with applications in both gate height and fin height. TEM correlation with R2 being 0.89 and precision of 0.81nm have been achieved on various in-die features in gate height application. Fin height measurement shows less accuracy (R2 being 0.77) and precision (1.49 nm) due to challenges brought by fin geometry, yet still promising as first attempt. Sensitivity to DOE offset, die-to-die and in-die variation is demonstrated in both gate height and fin height. Process defect is successfully captured from inline wafers with gate height measurement implemented in production. This is the first successful demonstration of inline in-die gate height measurement for 14nm FinFET process control.

Assessment of the present NASA optical metrology capabilities and recommendations for establishing an in-house NASA Optical Metrology Group

NASA Technical Reports Server (NTRS)

Parks, Robert E.

1991-01-01

An investigation into when it was first recognized that there was a deficiency in NASA optical metrology oversight capability, why this deficiency existed unnoticed for so long, and a proposal for correcting the problem is presented. It is explained why this optical metrology oversight is so critical to program success and at the same time, why it is difficult to establish due to the nature of the technology. The solution proposed is the establishment of an Optics Metrology Group within the NASA/MSFC Optics Branch with a line of authority from NASA S & MA.

In-Line Detection and Measurement of Molecular Contamination in Semiconductor Process Solutions

NASA Astrophysics Data System (ADS)

Wang, Jason; West, Michael; Han, Ye; McDonald, Robert C.; Yang, Wenjing; Ormond, Bob; Saini, Harmesh

2005-09-01

This paper discusses a fully automated metrology tool for detection and quantitative measurement of contamination, including cationic, anionic, metallic, organic, and molecular species present in semiconductor process solutions. The instrument is based on an electrospray ionization time-of-flight mass spectrometer (ESI-TOF/MS) platform. The tool can be used in diagnostic or analytical modes to understand process problems in addition to enabling routine metrology functions. Metrology functions include in-line contamination measurement with near real-time trend analysis. This paper discusses representative organic and molecular contamination measurement results in production process problem solving efforts. The examples include the analysis and identification of organic compounds in SC-1 pre-gate clean solution; urea, NMP (N-Methyl-2-pyrrolidone) and phosphoric acid contamination in UPW; and plasticizer and an organic sulfur-containing compound found in isopropyl alcohol (IPA). It is expected that these unique analytical and metrology capabilities will improve the understanding of the effect of organic and molecular contamination on device performance and yield. This will permit the development of quantitative correlations between contamination levels and process degradation. It is also expected that the ability to perform routine process chemistry metrology will lead to corresponding improvements in manufacturing process control and yield, the ability to avoid excursions and will improve the overall cost effectiveness of the semiconductor manufacturing process.

High-NA optical CD metrology on small in-cell targets enabling improved higher order dose control and process control for logic

NASA Astrophysics Data System (ADS)

Cramer, Hugo; Mc Namara, Elliott; van Laarhoven, Rik; Jaganatharaja, Ram; de la Fuente, Isabel; Hsu, Sharon; Belletti, Filippo; Popadic, Milos; Tu, Ward; Huang, Wade

2017-03-01

The logic manufacturing process requires small in-device metrology targets to exploit the full dose correction potential of the modern scanners and process tools. A high-NA angular resolved scatterometer (YieldStar S-1250D) was modified to demonstrate the possibility of OCD measurements on 5x5µm2 targets. The results obtained on test wafers in a logic manufacturing environment, measured after litho and after core etch, showed a good correlation to larger reference targets and AEI to ADI intra-field CDU correlation, thereby demonstrating the feasibility of OCD on such small targets. The data was used to determine a reduction potential of 55% for the intra-field CD variation, using 145 points per field on a few inner fields, and 33% of the process induced across wafer CD variation using 16 points per field full wafer. In addition, the OCD measurements reveal valuable information on wafer-to-wafer layer height variations within a lot.

Framework for SEM contour analysis

NASA Astrophysics Data System (ADS)

Schneider, L.; Farys, V.; Serret, E.; Fenouillet-Beranger, C.

2017-03-01

SEM images provide valuable information about patterning capability. Geometrical properties such as Critical Dimension (CD) can be extracted from them and are used to calibrate OPC models, thus making OPC more robust and reliable. However, there is currently a shortage of appropriate metrology tools to inspect complex two-dimensional patterns in the same way as one would work with simple one-dimensional patterns. In this article we present a full framework for the analysis of SEM images. It has been proven to be fast, reliable and robust for every type of structure, and particularly for two-dimensional structures. To achieve this result, several innovative solutions have been developed and will be presented in the following pages. Firstly, we will present a new noise filter which is used to reduce noise on SEM images, followed by an efficient topography identifier, and finally we will describe the use of a topological skeleton as a measurement tool that can extend CD measurements on all kinds of patterns.

Optical critical dimension metrology for directed self-assembly assisted contact hole shrink

NASA Astrophysics Data System (ADS)

Dixit, Dhairya; Green, Avery; Hosler, Erik R.; Kamineni, Vimal; Preil, Moshe E.; Keller, Nick; Race, Joseph; Chun, Jun Sung; O'Sullivan, Michael; Khare, Prasanna; Montgomery, Warren; Diebold, Alain C.

2016-01-01

Directed self-assembly (DSA) is a potential patterning solution for future generations of integrated circuits. Its main advantages are high pattern resolution (˜10 nm), high throughput, no requirement of high-resolution mask, and compatibility with standard fab-equipment and processes. The application of Mueller matrix (MM) spectroscopic ellipsometry-based scatterometry to optically characterize DSA patterned contact hole structures fabricated with phase-separated polystyrene-b-polymethylmethacrylate (PS-b-PMMA) is described. A regression-based approach is used to calculate the guide critical dimension (CD), DSA CD, height of the PS column, thicknesses of underlying layers, and contact edge roughness of the post PMMA etch DSA contact hole sample. Scanning electron microscopy and imaging analysis is conducted as a comparative metric for scatterometry. In addition, optical model-based simulations are used to investigate MM elements' sensitivity to various DSA-based contact hole structures, predict sensitivity to dimensional changes, and its limits to characterize DSA-induced defects, such as hole placement inaccuracy, missing vias, and profile inaccuracy of the PMMA cylinder.

The impact of 14nm photomask variability and uncertainty on computational lithography solutions

NASA Astrophysics Data System (ADS)

Sturtevant, John; Tejnil, Edita; Buck, Peter D.; Schulze, Steffen; Kalk, Franklin; Nakagawa, Kent; Ning, Guoxiang; Ackmann, Paul; Gans, Fritz; Buergel, Christian

2013-09-01

Computational lithography solutions rely upon accurate process models to faithfully represent the imaging system output for a defined set of process and design inputs. These models rely upon the accurate representation of multiple parameters associated with the scanner and the photomask. Many input variables for simulation are based upon designed or recipe-requested values or independent measurements. It is known, however, that certain measurement methodologies, while precise, can have significant inaccuracies. Additionally, there are known errors associated with the representation of certain system parameters. With shrinking total CD control budgets, appropriate accounting for all sources of error becomes more important, and the cumulative consequence of input errors to the computational lithography model can become significant. In this work, we examine via simulation, the impact of errors in the representation of photomask properties including CD bias, corner rounding, refractive index, thickness, and sidewall angle. The factors that are most critical to be accurately represented in the model are cataloged. CD bias values are based on state of the art mask manufacturing data and other variables changes are speculated, highlighting the need for improved metrology and communication between mask and OPC model experts. The simulations are done by ignoring the wafer photoresist model, and show the sensitivity of predictions to various model inputs associated with the mask. It is shown that the wafer simulations are very dependent upon the 1D/2D representation of the mask and for 3D, that the mask sidewall angle is a very sensitive factor influencing simulated wafer CD results.

Instrumentation and Metrology for Nanotechnology

DTIC Science & Technology

2004-01-29

dimension measurements of 3D structures, overlay, defect detection, and analysis . Critical dimension ( CD ) measurement must account for sidewall shape and...critical dimension measurements of 3D structures, overlay, defect detection, and analysis . CD measurement must account for sidewall shape and line...energy dispersive X-ray (EDX) analysis on films containing as-prepared FePt nanoparticles revealed a distribution of particle compositions. Although

A new critical dimension metrology for chrome-on-glass substrates based on s-parameter measurements extracted from coplanar waveguide test structures

NASA Astrophysics Data System (ADS)

Nwokoye, Chidubem A.; Zaghloul, Mona; Cresswell, Michael W.; Allen, Richard A.; Murabito, Christine E.

2006-10-01

The technical objective of the work reported here is to assess whether radio-frequency (RF) measurements made on coplanar waveguide (CPW) test structures, which are replicated in conducting material on insulating substrates, could be employed to extract the critical dimension (CD) of the signal line using its center-to-center separation from the groundlines as a reference. The specific near-term objective is to assess whether this CPW-based CD-metrology has sensitivity and repeatability competitive with the other metrology techniques that are now used for chrome-on-glass (COG) photomasks. An affirmative answer is encouraging because advancing to a non-contact and non-vacuum implementation would then seem possible for this application. Our modeling of specific cases shows that, when the pitch of the replicated lines of the CPW is maintained constant, the sensitivity of its characteristic impedance to the CDs of the signal and ground lines is approximately 60 Ω/μm. This is a potentially useful result. For the same implementation, the quantity ∂C/∂w has a value of approximately 45 (pF/m)/μm, which appears to be large enough to provide acceptable accuracy.

Holistic metrology qualification extension and its application to characterize overlay targets with asymmetric effects

NASA Astrophysics Data System (ADS)

Dos Santos Ferreira, Olavio; Sadat Gousheh, Reza; Visser, Bart; Lie, Kenrick; Teuwen, Rachel; Izikson, Pavel; Grzela, Grzegorz; Mokaberi, Babak; Zhou, Steve; Smith, Justin; Husain, Danish; Mandoy, Ram S.; Olvera, Raul

2018-03-01

Ever increasing need for tighter on-product overlay (OPO), as well as enhanced accuracy in overlay metrology and methodology, is driving semiconductor industry's technologists to innovate new approaches to OPO measurements. In case of High Volume Manufacturing (HVM) fabs, it is often critical to strive for both accuracy and robustness. Robustness, in particular, can be challenging in metrology since overlay targets can be impacted by proximity of other structures next to the overlay target (asymmetric effects), as well as symmetric stack changes such as photoresist height variations. Both symmetric and asymmetric contributors have impact on robustness. Furthermore, tweaking or optimizing wafer processing parameters for maximum yield may have an adverse effect on physical target integrity. As a result, measuring and monitoring physical changes or process abnormalities/artefacts in terms of new Key Performance Indicators (KPIs) is crucial for the end goal of minimizing true in-die overlay of the integrated circuits (ICs). IC manufacturing fabs often relied on CD-SEM in the past to capture true in-die overlay. Due to destructive and intrusive nature of CD-SEMs on certain materials, it's desirable to characterize asymmetry effects for overlay targets via inline KPIs utilizing YieldStar (YS) metrology tools. These KPIs can also be integrated as part of (μDBO) target evaluation and selection for final recipe flow. In this publication, the Holistic Metrology Qualification (HMQ) flow was extended to account for process induced (asymmetric) effects such as Grating Imbalance (GI) and Bottom Grating Asymmetry (BGA). Local GI typically contributes to the intrafield OPO whereas BGA typically impacts the interfield OPO, predominantly at the wafer edge. Stack height variations highly impact overlay metrology accuracy, in particular in case of multi-layer LithoEtch Litho-Etch (LELE) overlay control scheme. Introducing a GI impact on overlay (in nm) KPI check quantifies the grating imbalance impact on overlay, whereas optimizing for accuracy using self-reference captures the bottom grating asymmetry effect. Measuring BGA after each process step before exposure of the top grating helps to identify which specific step introduces the asymmetry in the bottom grating. By evaluating this set of KPI's to a BEOL LELE overlay scheme, we can enhance robustness of recipe selection and target selection. Furthermore, these KPIs can be utilized to highlight process and equipment abnormalities. In this work, we also quantified OPO results with a self-contained methodology called Triangle Method. This method can be utilized for LELE layers with a common target and reference. This allows validating general μDBO accuracy, hence reducing the need for CD-SEM verification.

3D interconnect metrology in CMS/ITRI

NASA Astrophysics Data System (ADS)

Ku, Y. S.; Shyu, D. M.; Hsu, W. T.; Chang, P. Y.; Chen, Y. C.; Pang, H. L.

2011-05-01

Semiconductor device packaging technology is rapidly advancing, in response to the demand for thinner and smaller electronic devices. Three-dimensional chip/wafer stacking that uses through-silicon vias (TSV) is a key technical focus area, and the continuous development of this novel technology has created a need for non-contact characterization. Many of these challenges are novel to the industry due to the relatively large variety of via sizes and density, and new processes such as wafer thinning and stacked wafer bonding. This paper summarizes the developing metrology that has been used during via-middle & via-last TSV process development at EOL/ITRI. While there is a variety of metrology and inspection applications for 3D interconnect processing, the main topics covered here are via CD/depth measurement, thinned wafer inspection and wafer warpage measurement.

Unique method for controlling device level overlay with high-NA optical overlay technique using YieldStar in a DRAM HVM environment

NASA Astrophysics Data System (ADS)

Park, Dong-Kiu; Kim, Hyun-Sok; Seo, Moo-Young; Ju, Jae-Wuk; Kim, Young-Sik; Shahrjerdy, Mir; van Leest, Arno; Soco, Aileen; Miceli, Giacomo; Massier, Jennifer; McNamara, Elliott; Hinnen, Paul; Böcker, Paul; Oh, Nang-Lyeom; Jung, Sang-Hoon; Chai, Yvon; Lee, Jun-Hyung

2018-03-01

This paper demonstrates the improvement using the YieldStar S-1250D small spot, high-NA, after-etch overlay in-device measurements in a DRAM HVM environment. It will be demonstrated that In-device metrology (IDM) captures after-etch device fingerprints more accurately compared to the industry-standard CDSEM. Also, IDM measurements (acquiring both CD and overlay) can be executed significantly faster increasing the wafer sampling density that is possible within a realistic metrology budget. The improvements to both speed and accuracy open the possibility of extended modeling and correction capabilities for control. The proof-book data of this paper shows a 36% improvement of device overlay after switching to control in a DRAM HVM environment using indevice metrology.

Development for 2D pattern quantification method on mask and wafer

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Toyoda, Yasutaka; Wang, Zhigang

2010-03-01

We have developed the effective method of mask and silicon 2-dimensional metrology. The aim of this method is evaluating the performance of the silicon corresponding to Hotspot on a mask. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and mask manufacture, and this has a big impact on the semiconductor market that centers on the mask business. 2-dimensional Shape quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. On the other hand, there is roughness in the silicon shape made from a mass-production line. Moreover, there is variation in the silicon shape. For this reason, quantification of silicon shape is important, in order to estimate the performance of a pattern. In order to quantify, the same shape is equalized in two dimensions. And the method of evaluating based on the shape is popular. In this study, we conducted experiments for averaging method of the pattern (Measurement Based Contouring) as two-dimensional mask and silicon evaluation technique. That is, observation of the identical position of a mask and a silicon was considered. It is possible to analyze variability of the edge of the same position with high precision. The result proved its detection accuracy and reliability of variability on two-dimensional pattern (mask and silicon) and is adaptable to following fields of mask quality management. - Estimate of the correlativity of shape variability and a process margin. - Determination of two-dimensional variability of pattern. - Verification of the performance of the pattern of various kinds of Hotspots. In this report, we introduce the experimental results and the application. We expect that the mask measurement and the shape control on mask production will make a huge contribution to mask yield-enhancement and that the DFM solution for mask quality control process will become much more important technology than ever. It is very important to observe the shape of the same location of Design, Mask, and Silicon in such a viewpoint.

Improved shallow trench isolation and gate process control using scatterometry based metrology

NASA Astrophysics Data System (ADS)

Rudolph, P.; Bradford, S. M.

2005-05-01

The ability to control critical dimensions of structures on semiconductor devices is essential to improving die yield and device performance. As geometries shrink, accuracy of the metrology equipment has increasingly become a contributing factor to the inability to detect shifts which result in yield loss. Scatterometry provides optical measurement that better enables process control of critical dimensions. Superior precision, accuracy, and higher throughput can be achieved more cost effectively through the use of this technology in production facilities. This paper outlines the implementation of Scatterometry based metrology in a production facility. The accuracy advantage it has over conventional Scanning Electron Microscope (SEM) measurement is presented. The Scatterometry tool used has demonstrated repeatability on the order of 3σ < 1 nm at STI-Etch-FICD for CD and Trench Depth (TD), and Side Wall Angle (SWA) measurements to within 0.1 degrees. Poly CD also shows 3σ < 1 nm, and poly thickness measurement 3σ < 2.5 Å. Scatterometry has capabilities which include measurement of CD, structure height and trench depth, Sidewall angle (SWA), and film thickness. The greater accuracy and the addition of in-situ Trench depth and sidewall angle have provided new measurement capabilities. There are inherent difficulties in implementing scatterometry in production wafer fabs. Difficulties with photo resist measurements, film characterization and stack set-up will be discussed. In addition, there are challenges due to the quantity data generated, in how to organize and store this data effectively. A comparison of the advantages and shortcomings of the method are presented.

How much is enough? An analysis of CD measurement amount for mask characterization

NASA Astrophysics Data System (ADS)

Ullrich, Albrecht; Richter, Jan

2009-10-01

The demands on CD (critical dimension) metrology amount in terms of both reproducibility and measurement uncertainty steadily increase from node to node. Different mask characterization requirements have to be addressed like very small features, unevenly distributed features, contacts, semi-dense structures to name only a few. Usually this enhanced need is met by an increasing number of CD measurements, where the new CD requirements are added to the well established CD characterization recipe. This leads straight forwardly to prolonged cycle times and highly complex evaluation routines. At the same time mask processes are continuously improved to become more stable. The enhanced stability offers potential to actually reduce the number of measurements. Thus, in this work we will start to address the fundamental question of how many CD measurements are needed for mask characterization for a given confidence level. We used analysis of variances (ANOVA) to distinguish various contributors like mask making process, measurement tool stability and measurement methodology. These contributions have been investigated for classical photomask CD specifications e.g. mean to target, CD uniformity, target offset tolerance and x-y bias. We found depending on specification that the importance of the contributors interchanges. Interestingly, not only short and long-term metrology contributions are dominant. Also the number of measurements and their spatial distribution on the mask layout (sampling methodology) can be the most important part of the variance. The knowledge of contributions can be used to optimize the sampling plan. As a major finding, we conclude that there is potential to reduce a significant amount of measurements without loosing confidence at all. Here, full sampling in x and y as well as full sampling for different features can be shortened substantially almost up to 50%.

Programmed LWR metrology by multi-techniques approach

NASA Astrophysics Data System (ADS)

Reche, Jérôme; Besacier, Maxime; Gergaud, Patrice; Blancquaert, Yoann; Freychet, Guillaume; Labbaye, Thibault

2018-03-01

Nowadays, roughness control presents a huge challenge for the lithography step. For advanced nodes, this morphological aspect reaches the same order of magnitude than the Critical Dimension. Hence, the control of roughness needs an adapted metrology. In this study, specific samples with designed roughness have been manufactured using e-beam lithography. These samples have been characterized with three different methodologies: CD-SEM, OCD and SAXS. The main goal of the project is to compare the capability of each of these techniques in terms of reliability, type of information obtained, time to obtain the measurements and level of maturity for the industry.

Metrology for the manufacturing of freeform optics

NASA Astrophysics Data System (ADS)

Blalock, Todd; Myer, Brian; Ferralli, Ian; Brunelle, Matt; Lynch, Tim

2017-10-01

Recently the use of freeform surfaces have become a realization for optical designers. These non-symmetrical optical surfaces have allowed unique solutions to optical design problems. The implementation of freeform optical surfaces has been limited by manufacturing capabilities and quality. However over the past several years freeform fabrication processes have improved in capability and precision. But as with any manufacturing, proper metrology is required to monitor and verify the process. Typical optics metrology such as interferometry has its challenges and limitations with the unique shapes of freeform optics. Two contact metrology methods for freeform metrology are presented; a Leitz coordinate measurement machine (CMM) with an uncertainty of +/- 0.5 μm and a high resolution profilometer (Panasonic UA3P) with a measurement uncertainty of +/- 0.05 μm. We are also developing a non-contact high resolution technique based on the fringe reflection technique known as deflectometry. This fast non-contact metrology has the potential to compete with accuracies of the contact methods but also can acquire data in seconds rather than minutes or hours.

Application of advanced diffraction based optical metrology overlay capabilities for high-volume manufacturing

NASA Astrophysics Data System (ADS)

Chen, Kai-Hsiung; Huang, Guo-Tsai; Hsieh, Hung-Chih; Ni, Wei-Feng; Chuang, S. M.; Chuang, T. K.; Ke, Chih-Ming; Huang, Jacky; Rao, Shiuan-An; Cumurcu Gysen, Aysegul; d'Alfonso, Maxime; Yueh, Jenny; Izikson, Pavel; Soco, Aileen; Wu, Jon; Nooitgedagt, Tjitte; Ottens, Jeroen; Kim, Yong Ho; Ebert, Martin

2017-03-01

On-product overlay requirements are becoming more challenging with every next technology node due to the continued decrease of the device dimensions and process tolerances. Therefore, current and future technology nodes require demanding metrology capabilities such as target designs that are robust towards process variations and high overlay measurement density (e.g. for higher order process corrections) to enable advanced process control solutions. The impact of advanced control solutions based on YieldStar overlay data is being presented in this paper. Multi patterning techniques are applied for critical layers and leading to additional overlay measurement demands. The use of 1D process steps results in the need of overlay measurements relative to more than one layer. Dealing with the increased number of overlay measurements while keeping the high measurement density and metrology accuracy at the same time presents a challenge for high volume manufacturing (HVM). These challenges are addressed by the capability to measure multi-layer targets with the recently introduced YieldStar metrology tool, YS350. On-product overlay results of such multi-layers and standard targets are presented including measurement stability performance.

Reduction of wafer-edge overlay errors using advanced correction models, optimized for minimal metrology requirements

NASA Astrophysics Data System (ADS)

Kim, Min-Suk; Won, Hwa-Yeon; Jeong, Jong-Mun; Böcker, Paul; Vergaij-Huizer, Lydia; Kupers, Michiel; Jovanović, Milenko; Sochal, Inez; Ryan, Kevin; Sun, Kyu-Tae; Lim, Young-Wan; Byun, Jin-Moo; Kim, Gwang-Gon; Suh, Jung-Joon

2016-03-01

In order to optimize yield in DRAM semiconductor manufacturing for 2x nodes and beyond, the (processing induced) overlay fingerprint towards the edge of the wafer needs to be reduced. Traditionally, this is achieved by acquiring denser overlay metrology at the edge of the wafer, to feed field-by-field corrections. Although field-by-field corrections can be effective in reducing localized overlay errors, the requirement for dense metrology to determine the corrections can become a limiting factor due to a significant increase of metrology time and cost. In this study, a more cost-effective solution has been found in extending the regular correction model with an edge-specific component. This new overlay correction model can be driven by an optimized, sparser sampling especially at the wafer edge area, and also allows for a reduction of noise propagation. Lithography correction potential has been maximized, with significantly less metrology needs. Evaluations have been performed, demonstrating the benefit of edge models in terms of on-product overlay performance, as well as cell based overlay performance based on metrology-to-cell matching improvements. Performance can be increased compared to POR modeling and sampling, which can contribute to (overlay based) yield improvement. Based on advanced modeling including edge components, metrology requirements have been optimized, enabling integrated metrology which drives down overall metrology fab footprint and lithography cycle time.

Industrial Photogrammetry - Accepted Metrology Tool or Exotic Niche

NASA Astrophysics Data System (ADS)

Bösemann, Werner

2016-06-01

New production technologies like 3D printing and other adaptive manufacturing technologies have changed the industrial manufacturing process, often referred to as next industrial revolution or short industry 4.0. Such Cyber Physical Production Systems combine virtual and real world through digitization, model building process simulation and optimization. It is commonly understood that measurement technologies are the key to combine the real and virtual worlds (eg. [Schmitt 2014]). This change from measurement as a quality control tool to a fully integrated step in the production process has also changed the requirements for 3D metrology solutions. Key words like MAA (Measurement Assisted Assembly) illustrate that new position of metrology in the industrial production process. At the same time it is obvious that these processes not only require more measurements but also systems to deliver the required information in high density in a short time. Here optical solutions including photogrammetry for 3D measurements have big advantages over traditional mechanical CMM's. The paper describes the relevance of different photogrammetric solutions including state of the art, industry requirements and application examples.

Advanced applications of scatterometry based optical metrology

NASA Astrophysics Data System (ADS)

Dixit, Dhairya; Keller, Nick; Kagalwala, Taher; Recchia, Fiona; Lifshitz, Yevgeny; Elia, Alexander; Todi, Vinit; Fronheiser, Jody; Vaid, Alok

2017-03-01

The semiconductor industry continues to drive patterning solutions that enable devices with higher memory storage capacity, faster computing performance, and lower cost per transistor. These developments in the field of semiconductor manufacturing along with the overall minimization of the size of transistors require continuous development of metrology tools used for characterization of these complex 3D device architectures. Optical scatterometry or optical critical dimension (OCD) is one of the most prevalent inline metrology techniques in semiconductor manufacturing because it is a quick, precise and non-destructive metrology technique. However, at present OCD is predominantly used to measure the feature dimensions such as line-width, height, side-wall angle, etc. of the patterned nano structures. Use of optical scatterometry for characterizing defects such as pitch-walking, overlay, line edge roughness, etc. is fairly limited. Inspection of process induced abnormalities is a fundamental part of process yield improvement. It provides process engineers with important information about process errors, and consequently helps optimize materials and process parameters. Scatterometry is an averaging technique and extending it to measure the position of local process induced defectivity and feature-to-feature variation is extremely challenging. This report is an overview of applications and benefits of using optical scatterometry for characterizing defects such as pitch-walking, overlay and fin bending for advanced technology nodes beyond 7nm. Currently, the optical scatterometry is based on conventional spectroscopic ellipsometry and spectroscopic reflectometry measurements, but generalized ellipsometry or Mueller matrix spectroscopic ellipsometry data provides important, additional information about complex structures that exhibit anisotropy and depolarization effects. In addition the symmetry-antisymmetry properties associated with Mueller matrix (MM) elements provide an excellent means of measuring asymmetry present in the structure. The useful additional information as well as symmetry-antisymmetry properties of MM elements is used to characterize fin bending, overlay defects and design improvements in the OCD test structures are used to boost OCDs' sensitivity to pitch-walking. In addition, the validity of the OCD based results is established by comparing the results to the top down critical dimensionscanning electron microscope (CD-SEM) and cross-sectional transmission electron microscope (TEM) images.

High-volume manufacturing device overlay process control

NASA Astrophysics Data System (ADS)

Lee, Honggoo; Han, Sangjun; Woo, Jaeson; Lee, DongYoung; Song, ChangRock; Heo, Hoyoung; Brinster, Irina; Choi, DongSub; Robinson, John C.

2017-03-01

Overlay control based on DI metrology of optical targets has been the primary basis for run-to-run process control for many years. In previous work we described a scenario where optical overlay metrology is performed on metrology targets on a high frequency basis including every lot (or most lots) at DI. SEM based FI metrology is performed ondevice in-die as-etched on an infrequent basis. Hybrid control schemes of this type have been in use for many process nodes. What is new is the relative size of the NZO as compared to the overlay spec, and the need to find more comprehensive solutions to characterize and control the size and variability of NZO at the 1x nm node: sampling, modeling, temporal frequency and control aspects, as well as trade-offs between SEM throughput and accuracy.

Photomask linewidth comparison by PTB and NIST

NASA Astrophysics Data System (ADS)

Bergmann, D.; Bodermann, B.; Bosse, H.; Buhr, E.; Dai, G.; Dixson, R.; Häßler-Grohne, W.; Hahm, K.; Wurm, M.

2015-10-01

We report the initial results of a recent bilateral comparison of linewidth or critical dimension (CD) calibrations on photomask line features between two national metrology institutes (NMIs): the National Institute of Standards and Technology (NIST) in the United States and the Physikalisch-Technische Bundesanstalt (PTB) in Germany. For the comparison, a chrome on glass (CoG) photomask was used which has a layout of line features down to 100 nm nominal size. Different measurement methods were used at both institutes. These included: critical dimension atomic force microscopy (CD-AFM), CD scanning electron microscopy (CD-SEM) and ultraviolet (UV) transmission optical microscopy. The measurands are CD at 50 % height of the features as well as sidewall angle and line width roughness (LWR) of the features. On the isolated opaque features, we found agreement of the CD measurements at the 3 nm to 5 nm level on most features - usually within the combined expanded uncertainties of the measurements.

In Situ Metrology for the Corrective Polishing of Replicating Mandrels

DTIC Science & Technology

2010-06-08

distribution is unlimited. 13. SUPPLEMENTARY NOTES Presented at Mirror Technology Days, Boulder, Colorado, USA, 7-9 June 2010. 14...ABSTRACT The International X-ray Observatory (IXO) will require mandrel metrology with extremely tight tolerances on mirrors with up to 1.6 meter radii...ideal. Error budgets for the IXO mirror segments are presented. A potential solution is presented that uses a voice-coil controlled gauging head, air

Freeform metrology using subaperture stitching interferometry

NASA Astrophysics Data System (ADS)

Supranowitz, Chris; Lormeau, Jean-Pierre; Maloney, Chris; Murphy, Paul; Dumas, Paul

2016-11-01

As applications for freeform optics continue to grow, the need for high-precision metrology is becoming more of a necessity. Currently, coordinate measuring machines (CMM) that implement touch probes or optical probes can measure the widest ranges of shapes of freeform optics, but these measurement solutions often lack sufficient lateral resolution and accuracy. Subaperture stitching interferometry (SSI™) extends traditional Fizeau interferometry to provide accurate, high-resolution measurements of flats, spheres, and aspheres, and development is currently on-going to enable measurements of freeform surfaces. We will present recent freeform metrology results, including repeatability and cross-test data. We will also present MRF® polishing results where the stitched data was used as the input "hitmap" to the deterministic polishing process.

Tip Characterization Method using Multi-feature Characterizer for CD-AFM

PubMed Central

Orji, Ndubuisi G.; Itoh, Hiroshi; Wang, Chumei; Dixson, Ronald G.; Walecki, Peter S.; Schmidt, Sebastian W.; Irmer, Bernd

2016-01-01

In atomic force microscopy (AFM) metrology, the tip is a key source of uncertainty. Images taken with an AFM show a change in feature width and shape that depends on tip geometry. This geometric dilation is more pronounced when measuring features with high aspect ratios, and makes it difficult to obtain absolute dimensions. In order to accurately measure nanoscale features using an AFM, the tip dimensions should be known with a high degree of precision. We evaluate a new AFM tip characterizer, and apply it to critical dimension AFM (CD-AFM) tips used for high aspect ratio features. The characterizer is made up of comb-shaped lines and spaces, and includes a series of gratings that could be used as an integrated nanoscale length reference. We also demonstrate a simulation method that could be used to specify what range of tip sizes and shapes the characterizer can measure. Our experiments show that for non re-entrant features, the results obtained with this characterizer are consistent to 1 nm with the results obtained by using widely accepted but slower methods that are common practice in CD-AFM metrology. A validation of the integrated length standard using displacement interferometry indicates a uniformity of better than 0.75%, suggesting that the sample could be used as highly accurate and SI traceable lateral scale for the whole evaluation process. PMID:26720439

Aerial image metrology for OPC modeling and mask qualification

NASA Astrophysics Data System (ADS)

Chen, Ao; Foong, Yee Mei; Thaler, Thomas; Buttgereit, Ute; Chung, Angeline; Burbine, Andrew; Sturtevant, John; Clifford, Chris; Adam, Kostas; De Bisschop, Peter

2017-06-01

As nodes become smaller and smaller, the OPC applied to enable these nodes becomes more and more sophisticated. This trend peaks today in curve-linear OPC approaches that are currently starting to appear on the roadmap. With this sophistication of OPC, the mask pattern complexity increases. CD-SEM based mask qualification strategies as they are used today are starting to struggle to provide a precise forecast of the printing behavior of a mask on wafer. An aerial image CD measurement performed on ZEISS Wafer-Level CD system (WLCD) is a complementary approach to mask CD-SEMs to judge the lithographical performance of the mask and its critical production features. The advantage of the aerial image is that it includes all optical effects of the mask such as OPC, SRAF, 3D mask effects, once the image is taken under scanner equivalent illumination conditions. Additionally, it reduces the feature complexity and analyzes the printing relevant CD.

The LER/LWR metrology challenge for advance process control through 3D-AFM and CD-SEM

NASA Astrophysics Data System (ADS)

Faurie, P.; Foucher, J.; Foucher, A.-L.

2009-12-01

The continuous shrinkage in dimensions of microelectronic devices has reached such level, with typical gate length in advance R&D of less than 20nm combine with the introduction of new architecture (FinFET, Double gate...) and new materials (porous interconnect material, 193 immersion resist, metal gate material, high k materials...), that new process parameters have to be well understood and well monitored to guarantee sufficient production yield in a near future. Among these parameters, there are the critical dimensions (CD) associated to the sidewall angle (SWA) values, the line edge roughness (LER) and the line width roughness (LWR). Thus, a new metrology challenge has appeared recently and consists in measuring "accurately" the fabricated patterns on wafers in addition to measure the patterns on a repeatable way. Therefore, a great effort has to be done on existing techniques like CD-SEM, Scatterometry and 3D-AFM in order to develop them following the two previous criteria: Repeatability and Accuracy. In this paper, we will compare the 3D-AFM and CD-SEM techniques as a mean to measure LER and LWR on silicon and 193 resist and point out CD-SEM impact on the material during measurement. Indeed, depending on the material type, the interaction between the electron beam and the material or between the AFM tip and the material can vary a lot and subsequently can generate measurements bias. The first results tend to show that depending on CD-SEM conditions (magnification, number of acquisition frames) the final outputs can vary on a large range and therefore show that accuracy in such measurements are really not obvious to obtain. On the basis of results obtained on various materials that present standard sidewall roughness, we will show the limit of each technique and will propose different ways to improve them in order to fulfil advance roadmap requirements for the development of the next IC generation.

Writing next-generation display photomasks

NASA Astrophysics Data System (ADS)

Sandstrom, Tor; Wahlsten, Mikael; Park, Youngjin

2016-10-01

Recent years have seen a fast technical development within the display area. Displays get ever higher pixel density and the pixels get smaller. Current displays have over 800 PPI and market forces will eventually drive for densities of 2000 PPI or higher. The transistor backplanes also get more complex. OLED displays require 4-7 transistors per pixel instead of the typical 1-2 transistors used for LCDs, and they are significantly more sensitive to errors. New large-area maskwriters have been developed for masks used in high volume production of screens for state-of-theart smartphones. Redesigned laser optics with higher NA and lower aberrations improve resolution and CD uniformity and reduce mura effects. The number of beams has been increased to maintain the throughput despite the higher writing resolution. OLED displays are highly sensitive to placement errors and registration in the writers has been improved. To verify the registration of produced masks a separate metrology system has been developed. The metrology system is self-calibrated to high accuracy. The calibration is repeatable across machines and sites using Z-correction. The repeatability of the coordinate system makes it possible to standardize the coordinate system across an entire supply chain or indeed across the entire industry. In-house metrology is a commercial necessity for high-end mask shop, but also the users of the masks, the panel makers, would benefit from having in-house metrology. It would act as the reference for their mask suppliers, give better predictive and post mortem diagnostic power for the panel process, and the metrology could be used to characterize and improve the entire production loop from data to panel.

Optical Metrology for Directed Self-assembly Patterning Using Mueller Matrix Spectroscopic Ellipsometry Based Scatterometry

NASA Astrophysics Data System (ADS)

Dixit, Dhairya J.

The semiconductor industry continues to drive patterning solutions that enable devices with higher memory storage capacity, faster computing performance, lower cost per transistors, and higher transistor density. These developments in the field of semiconductor manufacturing along with the overall minimization of the size of transistors require cutting-edge metrology tools for characterization. Directed self-assembly (DSA) patterning process can be used to fabricate nanoscale line-space patterns and contact holes via thermodynamically driven micro-phase separation of block copolymer (BCP) films with boundary constraints from guiding templates. Its main advantages are high pattern resolution (~10 nm), high throughput, no requirement of a high-resolution mask, and compatibility with standard fab-equipment and processes. Although research into DSA patterning has demonstrated a high potential as a nanoscale patterning process, there are critical challenges that must be overcome before transferring DSA into high volume manufacturing, including achievement of low defect density and high process stability. For this, advances in critical dimension (CD) and overlay measurement as well as rapid defect characterization are required. Both scatterometry and critical dimension-scanning electron microscopy (CD-SEM) are routinely used for inline dimensional metrology. CD-SEM inspection is limited, as it does not easily provide detailed line-shape information, whereas scatterometry has the capability of measuring important feature dimensions including: line-width, line-shape, sidewall-angle, and thickness of the patterned samples quickly and non-destructively. The present work describes the application of Mueller matrix spectroscopic ellipsometry (MMSE) based scatterometry to optically characterize DSA patterned line- space grating and contact hole structures fabricated with phase-separated polystyrene-b-polymethylmethacrylate (PS-b-PMMA) at various integration steps of BCP DSA based patterning process. This work focuses on understanding the efficacy of MMSE base scatterometry for characterizing complex DSA structures. For example, the use of symmetry-antisymmetry properties associated with Mueller matrix (MM) elements to understand the topography of the periodic nanostructures and measure defectivity. Simulations (the forward problem approach of scatterometry) are used to investigate MM elements' sensitivity to changes in DSA structure such as one vs. two contact hole patterns and predict sensitivity to dimensional changes. A regression-based approach is used to extract feature shape parameters of the DSA structures by fitting simulated optical spectra to experimental optical spectra. Detection of the DSA defects is a key to reducing defect density for eventual manufacturability and production use of DSA process. Simulations of optical models of structures containing defects are used to evaluate the sensitivity of MM elements to DSA defects. This study describes the application of MMSE to determine the DSA pattern defectivity via spectral comparisons based on optical anisotropy and depolarization. The use of depolarization and optical anisotropy for characterization of experimental MMSE data is a very recent development in scatterometry. In addition, reconstructed scatterometry models are used to calculate line edge roughness in 28 nm pitch Si fins fabricated using DSA patterning process.

Elements for successful sensor-based process control {Integrated Metrology}

NASA Astrophysics Data System (ADS)

Butler, Stephanie Watts

1998-11-01

Current productivity needs have stimulated development of alternative metrology, control, and equipment maintenance methods. Specifically, sensor applications provide the opportunity to increase productivity, tighten control, reduce scrap, and improve maintenance schedules and procedures. Past experience indicates a complete integrated solution must be provided for sensor-based control to be used successfully in production. In this paper, Integrated Metrology is proposed as the term for an integrated solution that will result in a successful application of sensors for process control. This paper defines and explores the perceived four elements of successful sensor applications: business needs, integration, components, and form. Based upon analysis of existing successful commercially available controllers, the necessary business factors have been determined to be strong, measurable industry-wide business needs whose solution is profitable and feasible. This paper examines why the key aspect of integration is the decision making process. A detailed discussion is provided of the components of most importance to sensor based control: decision-making methods, the 3R's of sensors, and connectivity. A metric for one of the R's (resolution) is proposed to allow focus on this important aspect of measurement. A form for these integrated components which synergistically partitions various aspects of control at the equipment and MES levels to efficiently achieve desired benefits is recommended.

Optimized Biasing of Pump Laser Diodes in a Highly Reliable Metrology Source for Long-Duration Space Missions

NASA Technical Reports Server (NTRS)

Poberezhskiy, Ilya Y; Chang, Daniel H.; Erlig, Herman

2011-01-01

Optical metrology system reliability during a prolonged space mission is often limited by the reliability of pump laser diodes. We developed a metrology laser pump module architecture that meets NASA SIM Lite instrument optical power and reliability requirements by combining the outputs of multiple single-mode pump diodes in a low-loss, high port count fiber coupler. We describe Monte-Carlo simulations used to calculate the reliability of the laser pump module and introduce a combined laser farm aging parameter that serves as a load-sharing optimization metric. Employing these tools, we select pump module architecture, operating conditions, biasing approach and perform parameter sensitivity studies to investigate the robustness of the obtained solution.

Microfabricated Tactile Sensors for Biomedical Applications: A Review

PubMed Central

Saccomandi, Paola; Schena, Emiliano; Oddo, Calogero Maria; Zollo, Loredana; Silvestri, Sergio; Guglielmelli, Eugenio

2014-01-01

During the last decades, tactile sensors based on different sensing principles have been developed due to the growing interest in robotics and, mainly, in medical applications. Several technological solutions have been employed to design tactile sensors; in particular, solutions based on microfabrication present several attractive features. Microfabrication technologies allow for developing miniaturized sensors with good performance in terms of metrological properties (e.g., accuracy, sensitivity, low power consumption, and frequency response). Small size and good metrological properties heighten the potential role of tactile sensors in medicine, making them especially attractive to be integrated in smart interfaces and microsurgical tools. This paper provides an overview of microfabricated tactile sensors, focusing on the mean principles of sensing, i.e., piezoresistive, piezoelectric and capacitive sensors. These sensors are employed for measuring contact properties, in particular force and pressure, in three main medical fields, i.e., prosthetics and artificial skin, minimal access surgery and smart interfaces for biomechanical analysis. The working principles and the metrological properties of the most promising tactile, microfabricated sensors are analyzed, together with their application in medicine. Finally, the new emerging technologies in these fields are briefly described. PMID:25587432

Microfabricated tactile sensors for biomedical applications: a review.

PubMed

Saccomandi, Paola; Schena, Emiliano; Oddo, Calogero Maria; Zollo, Loredana; Silvestri, Sergio; Guglielmelli, Eugenio

2014-12-01

During the last decades, tactile sensors based on different sensing principles have been developed due to the growing interest in robotics and, mainly, in medical applications. Several technological solutions have been employed to design tactile sensors; in particular, solutions based on microfabrication present several attractive features. Microfabrication technologies allow for developing miniaturized sensors with good performance in terms of metrological properties (e.g., accuracy, sensitivity, low power consumption, and frequency response). Small size and good metrological properties heighten the potential role of tactile sensors in medicine, making them especially attractive to be integrated in smart interfaces and microsurgical tools. This paper provides an overview of microfabricated tactile sensors, focusing on the mean principles of sensing, i.e., piezoresistive, piezoelectric and capacitive sensors. These sensors are employed for measuring contact properties, in particular force and pressure, in three main medical fields, i.e., prosthetics and artificial skin, minimal access surgery and smart interfaces for biomechanical analysis. The working principles and the metrological properties of the most promising tactile, microfabricated sensors are analyzed, together with their application in medicine. Finally, the new emerging technologies in these fields are briefly described.

New method of contour-based mask-shape compiler

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Sugiyama, Akiyuki; Onizawa, Akira; Sato, Hidetoshi; Toyoda, Yasutaka

2007-10-01

We have developed a new method of accurately profiling a mask shape by utilizing a Mask CD-SEM. The method is intended to realize high accuracy, stability and reproducibility of the Mask CD-SEM adopting an edge detection algorithm as the key technology used in CD-SEM for high accuracy CD measurement. In comparison with a conventional image processing method for contour profiling, it is possible to create the profiles with much higher accuracy which is comparable with CD-SEM for semiconductor device CD measurement. In this report, we will introduce the algorithm in general, the experimental results and the application in practice. As shrinkage of design rule for semiconductor device has further advanced, an aggressive OPC (Optical Proximity Correction) is indispensable in RET (Resolution Enhancement Technology). From the view point of DFM (Design for Manufacturability), a dramatic increase of data processing cost for advanced MDP (Mask Data Preparation) for instance and surge of mask making cost have become a big concern to the device manufacturers. In a sense, it is a trade-off between the high accuracy RET and the mask production cost, while it gives a significant impact on the semiconductor market centered around the mask business. To cope with the problem, we propose the best method for a DFM solution in which two dimensional data are extracted for an error free practical simulation by precise reproduction of a real mask shape in addition to the mask data simulation. The flow centering around the design data is fully automated and provides an environment where optimization and verification for fully automated model calibration with much less error is available. It also allows complete consolidation of input and output functions with an EDA system by constructing a design data oriented system structure. This method therefore is regarded as a strategic DFM approach in the semiconductor metrology.

Process variation challenges and resolution in the negative-tone develop double patterning for 20nm and below technology node

NASA Astrophysics Data System (ADS)

Mehta, Sohan S.; Ganta, Lakshmi K.; Chauhan, Vikrant; Wu, Yixu; Singh, Sunil; Ann, Chia; Subramany, Lokesh; Higgins, Craig; Erenturk, Burcin; Srivastava, Ravi; Singh, Paramjit; Koh, Hui Peng; Cho, David

2015-03-01

Immersion based 20nm technology node and below becoming very challenging to chip designers, process and integration due to multiple patterning to integrate one design layer . Negative tone development (NTD) processes have been well accepted by industry experts for enabling technologies 20 nm and below. 193i double patterning is the technology solution for pitch down to 80 nm. This imposes tight control in critical dimension(CD) variation in double patterning where design patterns are decomposed in two different masks such as in litho-etch-litho etch (LELE). CD bimodality has been widely studied in LELE double patterning. A portion of CD tolerance budget is significantly consumed by variations in CD in double patterning. The objective of this work is to study the process variation challenges and resolution in the Negative Tone Develop Process for 20 nm and Below Technology Node. This paper describes the effect of dose slope on CD variation in negative tone develop LELE process. This effect becomes even more challenging with standalone NTD developer process due to q-time driven CD variation. We studied impact of different stacks with combination of binary and attenuated phase shift mask and estimated dose slope contribution individually from stack and mask type. Mask 3D simulation was carried out to understand theoretical aspect. In order to meet the minimum insulator requirement for the worst case on wafer the overlay and critical dimension uniformity (CDU) budget margins have slimmed. Besides the litho process and tool control using enhanced metrology feedback, the variation control has other dependencies too. Color balancing between the two masks in LELE is helpful in countering effects such as iso-dense bias, and pattern shifting. Dummy insertion and the improved decomposition techniques [2] using multiple lower priority constraints can help to a great extent. Innovative color aware routing techniques [3] can also help with achieving more uniform density and color balanced layouts.

Enabling Quantitative Optical Imaging for In-die-capable Critical Dimension Targets

PubMed Central

Barnes, B.M.; Henn, M.-A.; Sohn, M. Y.; Zhou, H.; Silver, R. M.

2017-01-01

Dimensional scaling trends will eventually bring semiconductor critical dimensions (CDs) down to only a few atoms in width. New optical techniques are required to address the measurement and variability for these CDs using sufficiently small in-die metrology targets. Recently, Qin et al. [Light Sci Appl, 5, e16038 (2016)] demonstrated quantitative model-based measurements of finite sets of lines with features as small as 16 nm using 450 nm wavelength light. This paper uses simulation studies, augmented with experiments at 193 nm wavelength, to adapt and optimize the finite sets of features that work as in-die-capable metrology targets with minimal increases in parametric uncertainty. A finite element based solver for time-harmonic Maxwell's equations yields two- and three-dimensional simulations of the electromagnetic scattering for optimizing the design of such targets as functions of reduced line lengths, fewer number of lines, fewer focal positions, smaller critical dimensions, and shorter illumination wavelength. Metrology targets that exceeded performance requirements are as short as 3 μm for 193 nm light, feature as few as eight lines, and are extensible to sub-10 nm CDs. Target areas measured at 193 nm can be fifteen times smaller in area than current state-of-the-art scatterometry targets described in the literature. This new methodology is demonstrated to be a promising alternative for optical model-based in-die CD metrology. PMID:28757674

Antenna Solar Energy to Electricity Converter (ASETEC)

DTIC Science & Technology

1989-11-01

radiation damage • x-ray masks: all aspects • synchrotron lithography • high brightness compact sources • x-ray lithography system considerations...IB.\\VAlmaden Research Center Cochairs: Daryl Ann Doane, DAD Technologies, Inc.; Elsa Reichmanis, AT&T Bell Laboratories This conferenc’.’ is a...Philips Research- Laboratories/Signetics Corporation DiaSY Nyyssonen, CD Metrology, Inc. Victor Pol, - AT&T Bell Laboratories Elsa Reichmanis

Development of an algorithm for monitoring pattern fidelity on photomasks for 0.2-μm technology and beyond based on light optical CD metrology tools

NASA Astrophysics Data System (ADS)

Schaetz, Thomas; Hay, Bernd; Walden, Lars; Ziegler, Wolfram

1999-04-01

With the ongoing shrinking of design rules, the complexity of photomasks does increase continuously. Features are getting smaller and denser, their characterization requires sophisticated procedures. Looking for the deviation from their target value and their linewidth variation is not sufficient any more. In addition, measurements of corner rounding and line end shortening are necessary to define the pattern fidelity on the mask. Otherwise printing results will not be satisfying. Contacts and small features are suffering mainly from imaging inaccuracies. The size of the contacts as an example may come out too small on the photomask and therefore reduces the process window in lithography. In order to meet customer requirements for pattern fidelity, a measurement algorithm and a measurement procedure needs to be introduced and specifications to be defined. In this paper different approaches are compared, allowing an automatic qualification of photomask by optical light microscopy based on a MueTec CD-metrology system, the newly developed MueTec 2030UV, provided with a 365 nm light source. The i-line illumination allows to resolve features down to 0.2 micrometers size with good repeatability.

[Report of the NEDO project "Research and development to promote the creation and utilization of an intellectual infrastructure: development of reference materials for laboratory medicine" "Development of pure substance-type certified reference materials"].

PubMed

Takatsu, Akiko

2009-06-01

There is an increasing demand to establish a metrological traceability system for in vitro diagnostics and medical devices. Pure substance-type reference materials are playing key roles in metrological traceability, because they form the basis for many traceability chains in chemistry. The National Metrology Institute of Japan (NMIJ), in the National Institute of Advanced Industrial Science and Technology (AIST), has been developing purity-certified reference materials (CRMs) in this field, such as cholesterol, creatinine, and urea. In the New Energy and Industrial Technology Development Organization (NEDO) project, entitled: "Research and Development to Promote the Creation and Utilization of an Intellectual Infrastructure: Development of Reference Materials for Laboratory Medicine", several pure substance-type CRMs were developed. For a pure protein solution CRM, amino acid analysis and nitrogen determination were chosen as the certification methods. The development and certification processes for the C-reactive protein (CRP) solution CRM were completed, with the recombinant human CRP solution as a candidate material. This CRP solution CRM is now available as NMIJ CRM. For cortisol CRM, a purified candidate material and highly pure primary reference material were prepared. Each impure compound in the materials was identified and quantified. The pure cortisol CRM will be available in 2009. These two CRMs provide a traceability link between routine clinical methods and the SI unit.

Reference metrology in a research fab: the NIST clean calibrations thrust

NASA Astrophysics Data System (ADS)

Dixson, Ronald; Fu, Joe; Orji, Ndubuisi; Renegar, Thomas; Zheng, Alan; Vorburger, Theodore; Hilton, Al; Cangemi, Marc; Chen, Lei; Hernandez, Mike; Hajdaj, Russell; Bishop, Michael; Cordes, Aaron

2009-03-01

In 2004, the National Institute of Standards and Technology (NIST) commissioned the Advanced Measurement Laboratory (AML) - a state-of-the-art, five-wing laboratory complex for leading edge NIST research. The NIST NanoFab - a 1765 m2 (19,000 ft2) clean room with 743 m2 (8000 ft2) of class 100 space - is the anchor of this facility and an integral component of the new Center for Nanoscale Science and Technology (CNST) at NIST. Although the CNST/NanoFab is a nanotechnology research facility with a different strategic focus than a current high volume semiconductor fab, metrology tools still play an important role in the nanofabrication research conducted here. Some of the metrology tools available to users of the NanoFab include stylus profiling, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Since 2001, NIST has collaborated with SEMATECH to implement a reference measurement system (RMS) using critical dimension atomic force microscopy (CD-AFM). NIST brought metrology expertise to the table and SEMATECH provided access to leading edge metrology tools in their clean room facility in Austin. Now, in the newly launched "clean calibrations" thrust at NIST, we are implementing the reference metrology paradigm on several tools in the CNST/NanoFab. Initially, we have focused on calibration, monitoring, and uncertainty analysis for a three-tool set consisting of a stylus profiler, an SEM, and an AFM. Our larger goal is the development of new and supplemental calibrations and standards that will benefit from the Class 100 environment available in the NanoFab and offering our customers calibration options that do not require exposing their samples to less clean environments. Toward this end, we have completed a preliminary evaluation of the performance of these instruments. The results of these evaluations suggest that the achievable uncertainties are generally consistent with our measurement goals.

OPC model data collection for 45-nm technology node using automatic CD-SEM offline recipe creation

NASA Astrophysics Data System (ADS)

Fischer, Daniel; Talbi, Mohamed; Wei, Alex; Menadeva, Ovadya; Cornell, Roger

2007-03-01

Optical and Process Correction in the 45nm node is requiring an ever higher level of characterization. The greater complexity drives a need for automation of the metrology process allowing more efficient, accurate and effective use of the engineering resources and metrology tool time in the fab, helping to satisfy what seems an insatiable appetite for data by lithographers and modelers charged with development of 45nm and 32nm processes. The scope of the work referenced here is a 45nm design cycle "full-loop automation", starting with gds formatted target design layout and ending with the necessary feedback of one and two dimensional printed wafer metrology. In this paper the authors consider the key elements of software, algorithmic framework and Critical Dimension Scanning Electron Microscope (CDSEM) functionality necessary to automate its recipe creation. We evaluate specific problems with the methodology of the former art, "on-tool on-wafer" recipe construction, and discuss how the implementation of the design based recipe generation improves upon the overall metrology process. Individual target-by-target construction, use of a one pattern recognition template fits all approach, a blind navigation to the desired measurement feature, lengthy sessions on tool to construct recipes and limited ability to determine measurement quality in the resultant data set are each discussed as to how the state of the art Design Based Metrology (DBM) approach is implemented. The offline created recipes have shown pattern recognition success rates of up to 100% and measurement success rates of up to 93% for line/space as well as for 2D Minimum/Maximum measurements without manual assists during measurement.

Automated mask and wafer defect classification using a novel method for generalized CD variation measurements

NASA Astrophysics Data System (ADS)

Verechagin, V.; Kris, R.; Schwarzband, I.; Milstein, A.; Cohen, B.; Shkalim, A.; Levy, S.; Price, D.; Bal, E.

2018-03-01

Over the years, mask and wafers defects dispositioning has become an increasingly challenging and time consuming task. With design rules getting smaller, OPC getting complex and scanner illumination taking on free-form shapes - the probability of a user to perform accurate and repeatable classification of defects detected by mask inspection tools into pass/fail bins is reducing. The critical challenging of mask defect metrology for small nodes ( < 30 nm) was reviewed in [1]. While Critical Dimension (CD) variation measurement is still the method of choice for determining a mask defect future impact on wafer, the high complexity of OPCs combined with high variability in pattern shapes poses a challenge for any automated CD variation measurement method. In this study, a novel approach for measurement generalization is presented. CD variation assessment performance is evaluated on multiple different complex shape patterns, and is benchmarked against an existing qualified measurement methodology.

Gravimetric preparation and characterization of primary reference solutions of molybdenum and rhodium.

PubMed

Kaltenbach, Angela; Noordmann, Janine; Görlitz, Volker; Pape, Carola; Richter, Silke; Kipphardt, Heinrich; Kopp, Gernot; Jährling, Reinhard; Rienitz, Olaf; Güttler, Bernd

2015-04-01

Gravimetrically prepared mono-elemental reference solutions having a well-known mass fraction of approximately 1 g/kg (or a mass concentration of 1 g/L) define the very basis of virtually all measurements in inorganic analysis. Serving as the starting materials of all standard/calibration solutions, they link virtually all measurements of inorganic analytes (regardless of the method applied) to the purity of the solid materials (high-purity metals or salts) they were prepared from. In case these solid materials are characterized comprehensively with respect to their purity, this link also establishes direct metrological traceability to The International System of Units (SI). This, in turn, ensures the comparability of all results on the highest level achievable. Several national metrology institutes (NMIs) and designated institutes (DIs) have been working for nearly two decades in close cooperation with commercial producers on making an increasing number of traceable reference solutions available. Besides the comprehensive characterization of the solid starting materials, dissolving them both loss-free and completely under strict gravimetric control is a challenging problem in the case of several elements like molybdenum and rhodium. Within the framework of the European Metrology Research Programme (EMRP), in the Joint Research Project (JRP) called SIB09 Primary standards for challenging elements, reference solutions of molybdenum and rhodium were prepared directly from the respective metals with a relative expanded uncertainty associated with the mass fraction of U rel(w) < 0.05 %. To achieve this, a microwave-assisted digestion procedure for Rh and a hotplate digestion procedure for Mo were developed along with highly accurate and precise inductively coupled plasma optical emission spectrometry (ICP OES) and multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) methods required to assist with the preparation and as dissemination tools.

Advanced Mathematical Tools in Metrology III

NASA Astrophysics Data System (ADS)

Ciarlini, P.

The Table of Contents for the book is as follows: * Foreword * Invited Papers * The ISO Guide to the Expression of Uncertainty in Measurement: A Bridge between Statistics and Metrology * Bootstrap Algorithms and Applications * The TTRSs: 13 Oriented Constraints for Dimensioning, Tolerancing & Inspection * Graded Reference Data Sets and Performance Profiles for Testing Software Used in Metrology * Uncertainty in Chemical Measurement * Mathematical Methods for Data Analysis in Medical Applications * High-Dimensional Empirical Linear Prediction * Wavelet Methods in Signal Processing * Software Problems in Calibration Services: A Case Study * Robust Alternatives to Least Squares * Gaining Information from Biomagnetic Measurements * Full Papers * Increase of Information in the Course of Measurement * A Framework for Model Validation and Software Testing in Regression * Certification of Algorithms for Determination of Signal Extreme Values during Measurement * A Method for Evaluating Trends in Ozone-Concentration Data and Its Application to Data from the UK Rural Ozone Monitoring Network * Identification of Signal Components by Stochastic Modelling in Measurements of Evoked Magnetic Fields from Peripheral Nerves * High Precision 3D-Calibration of Cylindrical Standards * Magnetic Dipole Estimations for MCG-Data * Transfer Functions of Discrete Spline Filters * An Approximation Method for the Linearization of Tridimensional Metrology Problems * Regularization Algorithms for Image Reconstruction from Projections * Quality of Experimental Data in Hydrodynamic Research * Stochastic Drift Models for the Determination of Calibration Intervals * Short Communications * Projection Method for Lidar Measurement * Photon Flux Measurements by Regularised Solution of Integral Equations * Correct Solutions of Fit Problems in Different Experimental Situations * An Algorithm for the Nonlinear TLS Problem in Polynomial Fitting * Designing Axially Symmetric Electromechanical Systems of Superconducting Magnetic Levitation in Matlab Environment * Data Flow Evaluation in Metrology * A Generalized Data Model for Integrating Clinical Data and Biosignal Records of Patients * Assessment of Three-Dimensional Structures in Clinical Dentistry * Maximum Entropy and Bayesian Approaches to Parameter Estimation in Mass Metrology * Amplitude and Phase Determination of Sinusoidal Vibration in the Nanometer Range using Quadrature Signals * A Class of Symmetric Compactly Supported Wavelets and Associated Dual Bases * Analysis of Surface Topography by Maximum Entropy Power Spectrum Estimation * Influence of Different Kinds of Errors on Imaging Results in Optical Tomography * Application of the Laser Interferometry for Automatic Calibration of Height Setting Micrometer * Author Index

Evaluating the effects of modeling errors for isolated finite three-dimensional targets

NASA Astrophysics Data System (ADS)

Henn, Mark-Alexander; Barnes, Bryan M.; Zhou, Hui

2017-10-01

Optical three-dimensional (3-D) nanostructure metrology utilizes a model-based metrology approach to determine critical dimensions (CDs) that are well below the inspection wavelength. Our project at the National Institute of Standards and Technology is evaluating how to attain key CD and shape parameters from engineered in-die capable metrology targets. More specifically, the quantities of interest are determined by varying the input parameters for a physical model until the simulations agree with the actual measurements within acceptable error bounds. As in most applications, establishing a reasonable balance between model accuracy and time efficiency is a complicated task. A well-established simplification is to model the intrinsically finite 3-D nanostructures as either periodic or infinite in one direction, reducing the computationally expensive 3-D simulations to usually less complex two-dimensional (2-D) problems. Systematic errors caused by this simplified model can directly influence the fitting of the model to the measurement data and are expected to become more apparent with decreasing lengths of the structures. We identify these effects using selected simulation results and present experimental setups, e.g., illumination numerical apertures and focal ranges, that can increase the validity of the 2-D approach.

Annual Review of Progress in Applied Computational Electromagnetics (5th), Held in Monterey, California on March 20-24 1989

DTIC Science & Technology

1989-01-01

circuit of the field equations of Maxwell ", Proc IRE, vol 32, Kay 1944, pp 360-367. 3. S. Akhtarzad P.B. Johns ,"Solution of Maxwell’s equations in three...ELFCTROMAGNETICS APPLIED TO INTEGRATED CIRCUIT MICROLITHOGRAPHY AND METROLOGY John C . Mould Jr. & Gregory L Wojc* Welinger Associates, 4410 El Camino Real, Los...1AICROLITHOGRAPHY AND METROLOGY John C . Mould Jr. & Gregory L Wo c * Weldlinger Associates, 4410 El Camino Real. Los Allos, Ca. 94022 1. Pholoreslat

In-line height profiling metrology sensor for zero defect production control

NASA Astrophysics Data System (ADS)

Snel, Rob; Winters, Jasper; Liebig, Thomas; Jonker, Wouter

2017-06-01

Contemporary production systems of mechanical precision parts show challenges as increased complexity, tolerances shrinking to sub-microns and yield losses that must be mastered to the extreme. More advanced automation and process control is required to accomplish this task. Often a solution based on feedforward/feedback control is chosen requiring innovative and more advanced in line metrology. This article concentrates first on the context of in line metrology for process control and then on the development of a specific in line height profiling sensor. The novel sensor technology is based on full field time domain white light interferometry which is well know from the quality lab. The novel metrology system is to be mounted close to the production equipment, as required to minimize time delay in the control loop, and is thereby fully exposed to vibrations. This sensor is innovated to perform in line with an orders of magnitude faster throughput than laboratory instruments; it's robust to withstand the rigors of workshops and has a height resolution that is in the nanometer range.

Optimizing Hybrid Metrology: Rigorous Implementation of Bayesian and Combined Regression.

PubMed

Henn, Mark-Alexander; Silver, Richard M; Villarrubia, John S; Zhang, Nien Fan; Zhou, Hui; Barnes, Bryan M; Ming, Bin; Vladár, András E

2015-01-01

Hybrid metrology, e.g., the combination of several measurement techniques to determine critical dimensions, is an increasingly important approach to meet the needs of the semiconductor industry. A proper use of hybrid metrology may yield not only more reliable estimates for the quantitative characterization of 3-D structures but also a more realistic estimation of the corresponding uncertainties. Recent developments at the National Institute of Standards and Technology (NIST) feature the combination of optical critical dimension (OCD) measurements and scanning electron microscope (SEM) results. The hybrid methodology offers the potential to make measurements of essential 3-D attributes that may not be otherwise feasible. However, combining techniques gives rise to essential challenges in error analysis and comparing results from different instrument models, especially the effect of systematic and highly correlated errors in the measurement on the χ 2 function that is minimized. Both hypothetical examples and measurement data are used to illustrate solutions to these challenges.

Measuring optical phase digitally in coherent metrology systems

NASA Astrophysics Data System (ADS)

Kelly, Damien P.; Ryle, James; Zhao, Liang; Sheridan, John T.

2017-05-01

The accurate measurement of optical phase has many applications in metrology. For biological samples, which appear transparent, the phase data provides information about the refractive index of the sample. In speckle metrology, the phase can be used to estimate stress and strains of a rough surface with high sensitivity. In this theoretical manuscript we compare and contrast the properties of two techniques for estimating the phase distribution of a wave field under the paraxial approximation: (I) A digital holographic system, and (II) An idealized phase retrieval system. Both systems use a CCD or CMOS array to measure the intensities of the wave fields that are reflected from or transmitted through the sample of interest. This introduces a numerical aspect to the problem. For the two systems above we examine how numerical calculations can limit the performance of these systems leading to a near-infinite number of possible solutions.

Consideration of correlativity between litho and etching shape

NASA Astrophysics Data System (ADS)

Matsuoka, Ryoichi; Mito, Hiroaki; Shinoda, Shinichi; Toyoda, Yasutaka

2012-03-01

We developed an effective method for evaluating the correlation of shape of Litho and Etching pattern. The purpose of this method, makes the relations of the shape after that is the etching pattern an index in wafer same as a pattern shape on wafer made by a lithography process. Therefore, this method measures the characteristic of the shape of the wafer pattern by the lithography process and can predict the hotspot pattern shape by the etching process. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used wafer CD-SEM. Currently, as semiconductor manufacture moves towards even smaller feature size, this necessitates more aggressive optical proximity correction (OPC) to drive the super-resolution technology (RET). In other words, there is a trade-off between highly precise RET and lithography management, and this has a big impact on the semiconductor market that centers on the semiconductor business. 2-dimensional shape of wafer quantification is important as optimal solution over these problems. Although 1-dimensional shape measurement has been performed by the conventional technique, 2-dimensional shape management is needed in the mass production line under the influence of RET. We developed the technique of analyzing distribution of shape edge performance as the shape management technique. In this study, we conducted experiments for correlation method of the pattern (Measurement Based Contouring) as two-dimensional litho and etch evaluation technique. That is, observation of the identical position of a litho and etch was considered. It is possible to analyze variability of the edge of the same position with high precision.

Automated aerial image based CD metrology initiated by pattern marking with photomask layout data

NASA Astrophysics Data System (ADS)

Davis, Grant; Choi, Sun Young; Jung, Eui Hee; Seyfarth, Arne; van Doornmalen, Hans; Poortinga, Eric

2007-05-01

The photomask is a critical element in the lithographic image transfer process from the drawn layout to the final structures on the wafer. The non-linearity of the imaging process and the related MEEF impose a tight control requirement on the photomask critical dimensions. Critical dimensions can be measured in aerial images with hardware emulation. This is a more recent complement to the standard scanning electron microscope measurement of wafers and photomasks. Aerial image measurement includes non-linear, 3-dimensional, and materials effects on imaging that cannot be observed directly by SEM measurement of the mask. Aerial image measurement excludes the processing effects of printing and etching on the wafer. This presents a unique contribution to the difficult process control and modeling tasks in mask making. In the past, aerial image measurements have been used mainly to characterize the printability of mask repair sites. Development of photomask CD characterization with the AIMS TM tool was motivated by the benefit of MEEF sensitivity and the shorter feedback loop compared to wafer exposures. This paper describes a new application that includes: an improved interface for the selection of meaningful locations using the photomask and design layout data with the Calibre TM Metrology Interface, an automated recipe generation process, an automated measurement process, and automated analysis and result reporting on a Carl Zeiss AIMS TM system.

Process effects resulting from an increased BARC thickness

NASA Astrophysics Data System (ADS)

Eakin, Ronald J.; Detweiler, Shangting F.; Stagaman, Gregory J.; Tesauro, Mark R.; Spak, Mark A.; Dammel, Ralph R.

1997-07-01

Process improvements attributed to the use of bottom anti- reflective coatings (B.A.R.C.s) are well documented. As our experience with these materials improves, so does our understanding of additional optimization. Recent supplier experiments suggest an increase in the thickness of AZR BARLiTM (bottom anti-reflective layer i-line) solution to reduce photoresist swing curve ratios. Also, changes in thin film stack on common substrates can adversely affect the degree of photoresist reflective notching. It is therefore of extreme importance to determine optimum thickness(es) of a B.A.R.C. material to ensure maximum process potential. We document several process effects in the conversion of a SRAM test device (0.38 - 0.45 micrometers) from a 650 angstrom to a 2000 angstrom BARLiTM film thickness using conventional i-line photolithography. Critical dimension (CD) uniformity and depth of focus (DOF) are evaluated. Defect density between the two processes are compared before and after etch employing optical metrology and electrical test structures. Sensitivity of overlay as a function of BARLiTM film thickness is investigated as well.

Effect of chloride in soil solution on the plant availability of biosolid-borne cadmium.

PubMed

Weggler, Karin; McLaughlin, Michael J; Graham, Robin D

2004-01-01

Increasing chloride (Cl) concentration in soil solution has been shown to increase cadmium (Cd) concentration in soil solution and Cd uptake by plants, when grown in phosphate fertilizer- or biosolid-amended soils. However, previous experiments did not distinguish between the effect of Cl on biosolid-borne Cd compared with soil-borne Cd inherited from previous fertilizer history. A factorial pot experiment was conducted with biosolid application rates of 0, 20, 40, and 80 g biosolids kg(-1) and Cl concentration in soil solution ranging from 1 to 160 mM Cl. The Cd uptake of wheat (Triticum aestivum L. cv. Halberd) was measured and major cations and anions in soil solution were determined. Cadmium speciation in soil solution was calculated using GEOCHEM-PC. The Cd concentration in plant shoots and soil solution increased with biosolid application rates up to 40 g kg(-1), but decreased slightly in the 80 g kg(-1) biosolid treatment. Across biosolid application rates, the Cd concentration in soil solution and plant shoots was positively correlated with the Cl concentration in soil solution. This suggests that biosolid-borne Cd is also mobilized by chloride ligands in soil solution. The soil solution CdCl+ activity correlated best with the Cd uptake of plants, although little of the variation in plant Cd concentrations was explained by activity of CdCl+ in higher sludge treatments. It was concluded that chlorocomplexation of Cd increased the phytoavailability of biosolid-borne Cd to a similar degree as soil (fertilizer) Cd. There was a nonlinear increase in plant uptake and solubility of Cd in biosolid-amended soils, with highest plant Cd found at the 40 g kg(-1) rate of biosolid application, and higher rates (80 g kg(-1)) producing lower plant Cd uptake and lower Cd solubility in soil. This is postulated to be a result of Cd retention by CaCO3 formed as a result of the high alkalinity induced by biosolid application.

Scanner focus metrology and control system for advanced 10nm logic node

NASA Astrophysics Data System (ADS)

Oh, Junghun; Maeng, Kwang-Seok; Shin, Jae-Hyung; Choi, Won-Woong; Won, Sung-Keun; Grouwstra, Cedric; El Kodadi, Mohamed; Heil, Stephan; van der Meijden, Vidar; Hong, Jong Kyun; Kim, Sang-Jin; Kwon, Oh-Sung

2018-03-01

Immersion lithography is being extended beyond the 10-nm node and the lithography performance requirement needs to be tightened further to ensure good yield. Amongst others, good on-product focus control with accurate and dense metrology measurements is essential to enable this. In this paper, we will present new solutions that enable onproduct focus monitoring and control (mean and uniformity) suitable for high volume manufacturing environment. We will introduce the concept of pure focus and its role in focus control through the imaging optimizer scanner correction interface. The results will show that the focus uniformity can be improved by up to 25%.

Metrological challenges for measurements of key climatological observables, Part 4: Atmospheric relative humidity

PubMed Central

Lovell-Smith, J W; Feistel, R; Harvey, A H; Hellmuth, O; Bell, S A; Heinonen, M; Cooper, J R

2016-01-01

Water in its three ambient phases plays the central thermodynamic role in the terrestrial climate system. Clouds control Earth’s radiation balance, atmospheric water vapour is the strongest “greenhouse” gas, and non-equilibrium relative humidity at the air-sea interface drives evaporation and latent heat export from the ocean. In this paper, we examine the climatologically relevant atmospheric relative humidity, noting fundamental deficiencies in the definition of this key observable. The metrological history of this quantity is reviewed, problems with its current definition and measurement practice are analysed, and options for future improvements are discussed in conjunction with the recent seawater standard TEOS-10. It is concluded that the International Bureau of Weights and Measures, (BIPM), in cooperation with the International Association for the Properties of Water and Steam, IAPWS, along with other international organisations and institutions, can make significant contributions by developing and recommending state-of-the-art solutions for this long standing metrological problem, such as are suggested here. PMID:26877551

Optimizing Hybrid Metrology: Rigorous Implementation of Bayesian and Combined Regression

PubMed Central

Henn, Mark-Alexander; Silver, Richard M.; Villarrubia, John S.; Zhang, Nien Fan; Zhou, Hui; Barnes, Bryan M.; Ming, Bin; Vladár, András E.

2015-01-01

Hybrid metrology, e.g., the combination of several measurement techniques to determine critical dimensions, is an increasingly important approach to meet the needs of the semiconductor industry. A proper use of hybrid metrology may yield not only more reliable estimates for the quantitative characterization of 3-D structures but also a more realistic estimation of the corresponding uncertainties. Recent developments at the National Institute of Standards and Technology (NIST) feature the combination of optical critical dimension (OCD) measurements and scanning electron microscope (SEM) results. The hybrid methodology offers the potential to make measurements of essential 3-D attributes that may not be otherwise feasible. However, combining techniques gives rise to essential challenges in error analysis and comparing results from different instrument models, especially the effect of systematic and highly correlated errors in the measurement on the χ2 function that is minimized. Both hypothetical examples and measurement data are used to illustrate solutions to these challenges. PMID:26681991

Report of the CCQM-K97: measurement of arsenobetaine standard solution and arsenobetaine content in fish tissue (tunafish)

NASA Astrophysics Data System (ADS)

Ma, L. D.; Wang, J.; WEI, C.; Kuroiwa, T.; Narukawa, T.; Ito, N.; HIOKI, A.; CHIBA, K.; Yim, Y. H.; Lee, K. S.; Lim, Y. R.; Turk, G. C.; Davis, C. W.; Mester, Z.; Yang, L.; McCooeye, M.; Maxwell, P.; Cankur, O.; Tokman, N.; Coskun, F. G.

2017-01-01

The CCQM-K97 key comparison was organized by the inorganic analysis working group (IAWG) of CCQM as a follow-up to completed pilot study CCQM-P96 and P96.1 to test the abilities of the national metrology institutes to accurately quantitate the mass fraction of arsenobetaine (AsB) in standard solution and in fish tissue. A pilot study CCQM-P133 was parallelized with this key comparison. National Institute of Metrology (NIM), China and National Metrology Institute of Japan (NMIJ) acted as the coordinating laboratories. Six NMIs participated in CCQM-K97 and two institutes participated in CCQM-P133, and all of them submitted the results. Some NMIs submitted more than one results by different methods. The results were in excellent agreement with each other, and obviously better than those of previous P96 and P96.1. Therefore the calibrant which each NMI used was comparable. It shows that the capabilities of some of the participants have been improved after the previous pilot studies. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Easy parallel screening of reagent stability, quality control, and metrology in solid phase peptide synthesis (SPPS) and peptide couplings for microarrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Achyuthan, Komandoor E.; Wheeler, David R.

Evaluating the stability of coupling reagents, quality control (QC), and surface functionalization metrology are all critical to the production of high quality peptide microarrays. We describe a broadly applicable screening technique for evaluating the fidelity of solid phase peptide synthesis (SPPS), the stability of activation/coupling reagents, and a microarray surface metrology tool. This technique was used to assess the stability of the activation reagent 1-{[1-(Cyano-2-ethoxy-2-oxo-ethylidenaminooxy)dimethylamino-morpholinomethylene]}methaneaminiumHexafluorophosphate (COMU) (Sigma-Aldrich, St. Louis, MO, USA) by SPPS of Leu-Enkephalin (YGGFL) or the coupling of commercially synthesized YGGFL peptides to (3-aminopropyl)triethyoxysilane-modified glass surfaces. Coupling efficiency was quantitated by fluorescence signaling based on immunoreactivity of themore » YGGFL motif. It was concluded that COMU solutions should be prepared fresh and used within 5 h when stored at ~23 °C and not beyond 24 h if stored refrigerated, both in closed containers. Caveats to gauging COMU stability by absorption spectroscopy are discussed. Commercial YGGFL peptides needed independent QC, due to immunoreactivity variations for the same sequence synthesized by different vendors. This technique is useful in evaluating the stability of other activation/coupling reagents besides COMU and as a metrology tool for SPPS and peptide microarrays.« less

Easy parallel screening of reagent stability, quality control, and metrology in solid phase peptide synthesis (SPPS) and peptide couplings for microarrays

DOE PAGES

Achyuthan, Komandoor E.; Wheeler, David R.

2015-08-27

Evaluating the stability of coupling reagents, quality control (QC), and surface functionalization metrology are all critical to the production of high quality peptide microarrays. We describe a broadly applicable screening technique for evaluating the fidelity of solid phase peptide synthesis (SPPS), the stability of activation/coupling reagents, and a microarray surface metrology tool. This technique was used to assess the stability of the activation reagent 1-{[1-(Cyano-2-ethoxy-2-oxo-ethylidenaminooxy)dimethylamino-morpholinomethylene]}methaneaminiumHexafluorophosphate (COMU) (Sigma-Aldrich, St. Louis, MO, USA) by SPPS of Leu-Enkephalin (YGGFL) or the coupling of commercially synthesized YGGFL peptides to (3-aminopropyl)triethyoxysilane-modified glass surfaces. Coupling efficiency was quantitated by fluorescence signaling based on immunoreactivity of themore » YGGFL motif. It was concluded that COMU solutions should be prepared fresh and used within 5 h when stored at ~23 °C and not beyond 24 h if stored refrigerated, both in closed containers. Caveats to gauging COMU stability by absorption spectroscopy are discussed. Commercial YGGFL peptides needed independent QC, due to immunoreactivity variations for the same sequence synthesized by different vendors. This technique is useful in evaluating the stability of other activation/coupling reagents besides COMU and as a metrology tool for SPPS and peptide microarrays.« less

Fabrication High Resolution Metrology Target By Step And Repeat Method

NASA Astrophysics Data System (ADS)

Dusa, Mircea

1983-10-01

Based on the photolithography process generally used to generate high resolution masks for semiconductor I.C.S, we found a very useful industrial application of laser technology.First, we have generated high resolution metrology targets which are used in industrial measurement laser interferometers as difra.ction gratings. Secondi we have generated these targets using step and repeat machine, with He-Ne laser interferometer controlled state, as a pattern generator, due to suitable computer programming.Actually, high resolution metrology target, means two chromium plates, one of which is called the" rule" the other one the "vernier". In Fig.1 we have the configuration of the rule and the vernier. The rule has a succesion of 3 μM lines generated as a difraction grating on a 4 x 4 inch chromium blank. The vernier has several exposed fields( areas) having 3 - 15 μm lines, fields placed on very precise position on the chromium blank surface. High degree of uniformity, tight CD tolerances, low defect density required by the targets, creates specialised problems during processing. Details of the processing, together with experimental results will be presented. Before we start to enter into process details, we have to point out that the dimensional requirements of the reticle target, are quite similar or perhaps more strict than LSI master casks. These requirements presented in Fig.2.

In-line characterization of nanostructured mass-produced polymer components using scatterometry

NASA Astrophysics Data System (ADS)

Skovlund Madsen, Jonas; Højlund Thamdrup, Lasse; Czolkos, Ilja; Hansen, Poul Erik; Johansson, Alicia; Garnaes, Jørgen; Nygård, Jesper; Hannibal Madsen, Morten

2017-08-01

Scatterometry is used as an in-line metrology solution for injection molded nanostructures to evaluate the pattern replication fidelity. The method is used to give direct feedback to an operator when testing new molding parameters and for continuous quality control. A compact scatterometer has been built and tested at a fabrication facility. The scatterometry measurements, including data analysis and handling of the samples, are much faster than the injection molding cycle time, and thus, characterization does not slow down the production rate. Fabrication and characterization of 160 plastic parts with line gratings are presented here, and the optimal molding temperatures for replication of nanostructures are found for two polymers. Scatterometry results are compared to state of the art metrology solutions: atomic force and scanning electron microscopy. It is demonstrated that the scatterometer can determine the structural parameters of the samples with an accuracy of a few nanometers in less than a second, thereby enabling in-line characterization.

GPU accelerated Monte-Carlo simulation of SEM images for metrology

NASA Astrophysics Data System (ADS)

Verduin, T.; Lokhorst, S. R.; Hagen, C. W.

2016-03-01

In this work we address the computation times of numerical studies in dimensional metrology. In particular, full Monte-Carlo simulation programs for scanning electron microscopy (SEM) image acquisition are known to be notoriously slow. Our quest in reducing the computation time of SEM image simulation has led us to investigate the use of graphics processing units (GPUs) for metrology. We have succeeded in creating a full Monte-Carlo simulation program for SEM images, which runs entirely on a GPU. The physical scattering models of this GPU simulator are identical to a previous CPU-based simulator, which includes the dielectric function model for inelastic scattering and also refinements for low-voltage SEM applications. As a case study for the performance, we considered the simulated exposure of a complex feature: an isolated silicon line with rough sidewalls located on a at silicon substrate. The surface of the rough feature is decomposed into 408 012 triangles. We have used an exposure dose of 6 mC/cm2, which corresponds to 6 553 600 primary electrons on average (Poisson distributed). We repeat the simulation for various primary electron energies, 300 eV, 500 eV, 800 eV, 1 keV, 3 keV and 5 keV. At first we run the simulation on a GeForce GTX480 from NVIDIA. The very same simulation is duplicated on our CPU-based program, for which we have used an Intel Xeon X5650. Apart from statistics in the simulation, no difference is found between the CPU and GPU simulated results. The GTX480 generates the images (depending on the primary electron energy) 350 to 425 times faster than a single threaded Intel X5650 CPU. Although this is a tremendous speedup, we actually have not reached the maximum throughput because of the limited amount of available memory on the GTX480. Nevertheless, the speedup enables the fast acquisition of simulated SEM images for metrology. We now have the potential to investigate case studies in CD-SEM metrology, which otherwise would take unreasonable amounts of computation time.

Scatterometry measurement of nested lines, dual space, and rectangular contact CD on phase-shift masks

NASA Astrophysics Data System (ADS)

Lee, Kyung M.; Yedur, Sanjay; Henrichs, Sven; Tavassoli, Malahat; Baik, Kiho

2007-03-01

Evaluation of lithography process or stepper involves very large quantity of CD measurements and measurement time. In this paper, we report on a application of Scatterometry based metrology for evaluation of binary photomask lithography. Measurements were made on mask level with ODP scatterometer then on wafer with CD-SEM. 4 to 1 scaling from mask to wafer means 60nm line on wafer translates to 240nm on mask, easily measurable on ODP. Calculation of scatterometer profile information was performed by a in-situ library-based analysis (5sec/site). We characterized the CD uniformity, linearity, and metal film thickness uniformity. Results show that linearity measured from fixed-pitch, varying line/space ratio targets show good correlation to top-down CD-SEM with R2 of more than 0.99. ODP-SEM correlation results for variable pitch shows that careful examination of scatterometer profile results in order to obtain better correlation to CD SEM, since both tools react differently to the target profile variation. ODP results show that global CD distribution is clearly measurable with less outliers compared to CD SEM data. This is thought to be due to 'averaging' effect of scatterometer. The data show that Scatterometry provides a nondestructive and faster mean of characterizing lithography stepper performanceprofiles. APSM 1st level (before Cr removal) 'dual-space' CDs and EPSM rectangular contacts were also measured with and results demonstrates that Scatterometer is capable of measuring these targets with reasonable correlation to SEM.

The Underwater Spectrometric System Based on CZT Detector for Survey of the Bottom of MR Reactor Pool - 13461

DOE Office of Scientific and Technical Information (OSTI.GOV)

Potapov, Victor; Safronov, Alexey; Ivanov, Oleg

2013-07-01

The underwater spectrometer system for detection of irradiated nuclear fuel on the pool bottom of the reactor was elaborated. During the development process metrological studies of CdZnTe (CZT) detectors were conducted. These detectors are designed for spectrometric measurements in high radiation fields. A mathematical model based on the Monte Carlo method was created to evaluate the capability of such a system. A few experimental models were realized and the characteristics of the spectrometric system are represented. (authors)

Scatterometry on pelliclized masks: an option for wafer fabs

NASA Astrophysics Data System (ADS)

Gallagher, Emily; Benson, Craig; Higuchi, Masaru; Okumoto, Yasuhiro; Kwon, Michael; Yedur, Sanjay; Li, Shifang; Lee, Sangbong; Tabet, Milad

2007-03-01

Optical scatterometry-based metrology is now widely used in wafer fabs for lithography, etch, and CMP applications. This acceptance of a new metrology method occurred despite the abundance of wellestablished CD-SEM and AFM methods. It was driven by the desire to make measurements faster and with a lower cost of ownership. Over the last year, scatterometry has also been introduced in advanced mask shops for mask measurements. Binary and phase shift masks have been successfully measured at all desired points during photomask production before the pellicle is mounted. There is a significant benefit to measuring masks with the pellicle in place. From the wafer fab's perspective, through-pellicle metrology would verify mask effects on the same features that are characterized on wafer. On-site mask verification would enable quality control and trouble-shooting without returning the mask to a mask house. Another potential application is monitoring changes to mask films once the mask has been delivered to the fab (haze, oxide growth, etc.). Similar opportunities apply to the mask metrologist receiving line returns from a wafer fab. The ability to make line-return measurements without risking defect introduction is clearly attractive. This paper will evaluate the feasibility of collecting scatterometry data on pelliclized masks. We explore the effects of several different pellicle types on scatterometry measurements made with broadband light in the range of 320-780 nm. The complexity introduced by the pellicles' optical behavior will be studied.

Data fusion for CD metrology: heterogeneous hybridization of scatterometry, CDSEM, and AFM data

NASA Astrophysics Data System (ADS)

Hazart, J.; Chesneau, N.; Evin, G.; Largent, A.; Derville, A.; Thérèse, R.; Bos, S.; Bouyssou, R.; Dezauzier, C.; Foucher, J.

2014-04-01

The manufacturing of next generation semiconductor devices forces metrology tool providers for an exceptional effort in order to meet the requirements for precision, accuracy and throughput stated in the ITRS. In the past years hybrid metrology (based on data fusion theories) has been investigated as a new methodology for advanced metrology [1][2][3]. This paper provides a new point of view of data fusion for metrology through some experiments and simulations. The techniques are presented concretely in terms of equations to be solved. The first point of view is High Level Fusion which is the use of simple numbers with their associated uncertainty postprocessed by tools. In this paper, it is divided into two stages: one for calibration to reach accuracy, the second to reach precision thanks to Bayesian Fusion. From our perspective, the first stage is mandatory before applying the second stage which is commonly presented [1]. However a reference metrology system is necessary for this fusion. So, precision can be improved if and only if the tools to be fused are perfectly matched at least for some parameters. We provide a methodology similar to a multidimensional TMU able to perform this matching exercise. It is demonstrated on a 28 nm node backend lithography case. The second point of view is Deep Level Fusion which works on the contrary with raw data and their combination. In the approach presented here, the analysis of each raw data is based on a parametric model and connections between the parameters of each tool. In order to allow OCD/SEM Deep Level Fusion, a SEM Compact Model derived from [4] has been developed and compared to AFM. As far as we know, this is the first time such techniques have been coupled at Deep Level. A numerical study on the case of a simple stack for lithography is performed. We show strict equivalence of Deep Level Fusion and High Level Fusion when tools are sensitive and models are perfect. When one of the tools can be considered as a reference and the second is biased, High Level Fusion is far superior to standard Deep Level Fusion. Otherwise, only the second stage of High Level Fusion is possible (Bayesian Fusion) and do not provide substantial advantage. Finally, when OCD is equipped with methods for bias detection [5], Deep Level Fusion outclasses the two-stage High Level Fusion and will benefit to the industry for most advanced nodes production.

Full-chip level MEEF analysis using model based lithography verification

NASA Astrophysics Data System (ADS)

Kim, Juhwan; Wang, Lantian; Zhang, Daniel; Tang, Zongwu

2005-11-01

MEEF (Mask Error Enhancement Factor) has become a critical factor in CD uniformity control since optical lithography process moved to sub-resolution era. A lot of studies have been done by quantifying the impact of the mask CD (Critical Dimension) errors on the wafer CD errors1-2. However, the benefits from those studies were restricted only to small pattern areas of the full-chip data due to long simulation time. As fast turn around time can be achieved for the complicated verifications on very large data by linearly scalable distributed processing technology, model-based lithography verification becomes feasible for various types of applications such as post mask synthesis data sign off for mask tape out in production and lithography process development with full-chip data3,4,5. In this study, we introduced two useful methodologies for the full-chip level verification of mask error impact on wafer lithography patterning process. One methodology is to check MEEF distribution in addition to CD distribution through process window, which can be used for RET/OPC optimization at R&D stage. The other is to check mask error sensitivity on potential pinch and bridge hotspots through lithography process variation, where the outputs can be passed on to Mask CD metrology to add CD measurements on those hotspot locations. Two different OPC data were compared using the two methodologies in this study.

Potential of mosquito fern (Azolla caroliniana Willd.) plants as a biofilter for cadmium removal from waste water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sajwam, K.S.; Ornes, W.H.

1995-12-31

The aquatic vascular Mosquito Fern (Azolla Caroliania Willd.) was investigated as a potential biological filter for removal of Cd from waste water. Mosquito Fern plants were grown in and harvested weekly from 0.10 M Hoagland nutrient solutions containing 0.01, 0.04, and 1.03 {mu}g Cd mL{sup -1} or 0.50 M Hoagland nutrient solutions containing 0.02, 1.0, and 9.14,{mu}g Cd mL{sup -1}. Dry weights of plants significantly increased when exposed to all three Cd concentrations in 0. 10 M Hoagland solution through week three then decreased thereafter. However, in plants exposed to Cd treatments in 0.50 M Hoagland solution, dry weights increasedmore » through week one and decreased thereafter. Tissue Cd concentrations in plants grown in 0.10 M Hoagland solution increased during the first two weeks followed by decreases in week 3 and 4. However, tissue Cd increased through week 3 in plants grown in 0.50 M Hoagland solutions. Cadmium exposure to plants grown in 0.10 M Hoagland solution seemed to increase the tissue P concentrations in plants exposed to the lowest concentration of Cd. Tissue P in both control and treated plants in 0.50 M Hoagland solution seemed to increase over time with exception of the medium level (1 {mu}g Cd mL{sup -1}). These results suggest that Mosquito Fern would be useful for absorbing Cd from nutrient-rich water when the solution concentration was in the range of as low as 0.01 and as high as 9.14 {mu}g Cd mL{sup -1}. However, the harvest regime would have to be every one or two weeks to sustain plant vigor and realize maximum uptake of Cd from solution.« less

Mathematical calibration procedure of a capacitive sensor-based indexed metrology platform

NASA Astrophysics Data System (ADS)

Brau-Avila, A.; Santolaria, J.; Acero, R.; Valenzuela-Galvan, M.; Herrera-Jimenez, V. M.; Aguilar, J. J.

2017-03-01

The demand for faster and more reliable measuring tasks for the control and quality assurance of modern production systems has created new challenges for the field of coordinate metrology. Thus, the search for new solutions in coordinate metrology systems and the need for the development of existing ones still persists. One example of such a system is the portable coordinate measuring machine (PCMM), the use of which in industry has considerably increased in recent years, mostly due to its flexibility for accomplishing in-line measuring tasks as well as its reduced cost and operational advantages compared to traditional coordinate measuring machines. Nevertheless, PCMMs have a significant drawback derived from the techniques applied in the verification and optimization procedures of their kinematic parameters. These techniques are based on the capture of data with the measuring instrument from a calibrated gauge object, fixed successively in various positions so that most of the instrument measuring volume is covered, which results in time-consuming, tedious and expensive verification and optimization procedures. In this work the mathematical calibration procedure of a capacitive sensor-based indexed metrology platform (IMP) is presented. This calibration procedure is based on the readings and geometric features of six capacitive sensors and their targets with nanometer resolution. The final goal of the IMP calibration procedure is to optimize the geometric features of the capacitive sensors and their targets in order to use the optimized data in the verification procedures of PCMMs.

Computer aided manufacturing for complex freeform optics

NASA Astrophysics Data System (ADS)

Wolfs, Franciscus; Fess, Ed; Johns, Dustin; LePage, Gabriel; Matthews, Greg

2017-10-01

Recently, the desire to use freeform optics has been increasing. Freeform optics can be used to expand the capabilities of optical systems and reduce the number of optics needed in an assembly. The traits that increase optical performance also present challenges in manufacturing. As tolerances on freeform optics become more stringent, it is necessary to continue to improve methods for how the grinding and polishing processes interact with metrology. To create these complex shapes, OptiPro has developed a computer aided manufacturing package called PROSurf. PROSurf generates tool paths required for grinding and polishing freeform optics with multiple axes of motion. It also uses metrology feedback for deterministic corrections. ProSurf handles 2 key aspects of the manufacturing process that most other CAM systems struggle with. The first is having the ability to support several input types (equations, CAD models, point clouds) and still be able to create a uniform high-density surface map useable for generating a smooth tool path. The second is to improve the accuracy of mapping a metrology file to the part surface. To perform this OptiPro is using 3D error maps instead of traditional 2D maps. The metrology error map drives the tool path adjustment applied during processing. For grinding, the error map adjusts the tool position to compensate for repeatable system error. For polishing, the error map drives the relative dwell times of the tool across the part surface. This paper will present the challenges associated with these issues and solutions that we have created.

Determination of chemical availability of cadmium and zinc in soils using inert soil moisture samplers.

PubMed

Knight, B P; Chaudri, A M; McGrath, S P; Giller, K E

1998-01-01

A rapid method for extracting soil solutions using porous plastic soil-moisture samplers was combined with a cation resin equilibration based speciation technique to look at the chemical availability of metals in soil. Industrially polluted, metal sulphate amended and sewage sludge treated soils were used in our study. Cadmium sulphate amended and industrially contaminated soils all had > 65% of the total soil solution Cd present as free Cd2+. However, increasing total soil Cd concentrations by adding CdSO4 resulted in smaller total soil solution Cd. Consequently, the free Cd2+ concentrations in soil solutions extracted from these soils were smaller than in the same soil contaminated by sewage sludge addition. Amendment with ZnSO4 gave much greater concentrations of free Zn2+ in soil solutions compared with the same soil after long-term Zn contamination via sewage sludge additions. Our results demonstrate the difficulty in comparing total soil solution and free metal ion concentrations for soils from different areas with different physiochemical properties and sources of contamination. However, when comparing the same Woburn soil, Cd was much less available as Cd2+ in soil solution from the CdSO4 amended soils compared with soil contaminated by about 36 years of sewage sludge additions. In contrast, much more Zn was available in soil solution as free Zn2+ in the ZnSO4 amended soils compared with the sewage sludge treated soils.

Aseptic hydroponics to assess rhamnolipid-Cd and rhamnolipid-Zn bioavailability for sunflower (Helianthus annuus): a phytoextraction mechanism study.

PubMed

Wen, Jia; McLaughlin, Mike J; Stacey, Samuel P; Kirby, Jason K

2016-11-01

The availability of cadmium (Cd) and zinc (Zn) to sunflower (Helianthus annuus) was investigated in rhamnolipid- and ethylenediaminetetraacetic acid (EDTA)-buffered solutions in order to evaluate the influence of aqueous speciation of the metals on their uptake by the plant, in relation to predictions of uptake by the free ion activity model (FIAM). Free metal ion activity was estimated using the chemical equilibrium program MINTEQ or measured by Donnan dialysis. The uptake of Cd followed the FIAM for the EDTA-buffered solution at EDTA concentrations below 0.4 μM; for the rhamnolipid-buffered solution, the uptake of both metals in roots was not markedly affected by increasing rhamnolipid concentrations in solution. This suggests rhamnolipid enhanced metal accumulation in plant roots (per unit free metal in solution) possibly through formation and uptake of lipophilic complexes. The addition of normal Ca concentrations (low millimetre range) to the rhamnolipid uptake solutions reduced Cd accumulation in shoots by inhibiting Cd translocation, whereas it significantly increased Zn accumulation in shoots. This study confirms that although rhamnolipid could enhance accumulation of Cd in plants roots at low Ca supply, it is not suitable for Cd phytoextraction in contaminated soil environments where Ca concentrations in soil solution are orders of magnitude greater than those of Cd.

Development of a mushroom powder Certified Reference Material for calcium, arsenic, cadmium and lead measurements.

PubMed

Chew, Gina; Sim, Lay Peng; Ng, Sin Yee; Ding, Yi; Shin, Richard Y C; Lee, Tong Kooi

2016-01-01

Isotope dilution mass spectrometry and standard addition techniques were developed for the analysis of four elements (Ca, As, Cd and Pb) in a mushroom powder material. Results from the validated methods were compared to those of other national metrology institutes in the CCQM-K89 intercomparisons and the results were in excellent agreement with the reference values. The same methods were then used for the assignment of reference values to a mushroom powder Certified Reference Material (CRM). The certified values obtained for Ca, As, Cd and Pb were 1.444 ± 0.099 mg/g, 5.61 ± 0.59 mg/kg, 1.191 ± 0.079 mg/kg and 5.23 ± 0.94 mg/kg, respectively. The expanded measurement uncertainties were obtained by combining the uncertainty contributions from characterization (uchar) and between-bottle homogeneity (ubb). Copyright © 2015 Elsevier Ltd. All rights reserved.

How to measure a-few-nanometer-small LER occurring in EUV lithography processed feature

NASA Astrophysics Data System (ADS)

Kawada, Hiroki; Kawasaki, Takahiro; Kakuta, Junichi; Ikota, Masami; Kondo, Tsuyoshi

2018-03-01

For EUV lithography features we want to decrease the dose and/or energy of CD-SEM's probe beam because LER decreases with severe resist-material's shrink. Under such conditions, however, measured LER increases from true LER, due to LER bias that is fake LER caused by random noise in SEM image. A gap error occurs between the right and the left LERs. In this work we propose new procedures to obtain true LER by excluding the LER bias from the measured LER. To verify it we propose a LER's reference-metrology using TEM.

PREFACE: VII Brazilian Congress on Metrology (Metrologia 2013)

NASA Astrophysics Data System (ADS)

Costa-Félix, Rodrigo; Bernardes, Americo; Valente de Oliveira, José Carlos; Mauro Granjeiro, José; Epsztejn, Ruth; Ihlenfeld, Waldemar; Smarçaro da Cunha, Valnei

2015-01-01

SEVENTH BRAZILIAN CONGRESS ON METROLOGY (METROLOGIA 2013) Metrology and Quality for a Sustainable Development From November 24th to 27th 2013 was issued the Seventh Brazilian Congress on Metrology (Metrologia 2013), which is a biannual conference organized and sponsored by the Brazilian Society of Metrology (SBM) and the Brazilian National Institute of Metrology, Quality and Technology (Inmetro). This edition was held in the charming and historical city of Ouro Preto, MG, Brazil, and aimed to join people and institutions devoted to the dissemination of the metrology and conformity assessment. The Metrologia 2013 Conference consisted of Keynote Speeches (7) and regular papers (204). Among the regular papers, the 47 most outstanding ones, comprising a high quality content on Metrology and Conformity Assessment, were selected to be published in this issue of the Journal of Physics: Conference Series. The topics of the conference covered all important areas of Metrology, which were agglutinated in the following sessions in the present issue: . Physical Metrology (Acoustics, Vibration and Ultrasound; Electricity and Magnetism; Mechanics; Optics); . Metrology on Ionizing Radiations; . Time and Frequency; . Chemistry Metrology; . Materials Metrology; . Biotechnology; . Uncertainty, Statistics and Mathematics; . Legal Metrology; . Conformity Assessment. It is our great pleasure to present this volume of IOP Journal of Physics: Conference Series (JPCS) to the scientific community to promote further research in Metrology and related areas. We believe that this volume will be both an excellent source of scientific material in the fast evolving fields that were covered by Metrologia 2013. President of the congress Americo Bernardes Federal University of Ouro Preto atb@iceb.ufop.br Editor-in-chief Rodrigo Costa-Félix Brazilian National Institute of Metrology, Quality and Technology rpfelix@inmetro.gov.br Editors José Carlos Valente de Oliveira (Editor on Mechanical Metrology) Brazilian National Institute of Metrology, Quality and Technology jcoliveira@inmetro.gov.br José Mauro Granjeiro (Editor on Biotechnology) Brazilian National Institute of Metrology, Quality and Technology jmgranjeiro@inmetro.gov.br Ruth Epsztejn (Editor on Conformity Assessment) Brazilian National Institute of Metrology, Quality and Technology repsztejn@inmetro.gov.br Waldemar Ihlenfeld (Editor on Electrical Metrology) Brazilian National Institute of Metrology, Quality and Technology wgihlenfeld-pronametro@inmetro.gov.br Valnei Smarçaro da Cunha (Editor on Chemistry Metrology) Brazilian National Institute of Metrology, Quality and Technology vscunha@inmetro.gov.br Technical and Scientific Committee for Metrologia 2013 Ado Jório (UFMG) Carlos Achete (UFRJ, Inmetro) Flávio Vasconcelos (UFMG) Giorgio Moscati (USP) Hans Peter Grieneisen (Inmetro) Humberto Brandi (Inmetro) José Carlos Valente de Oliveira (Inmetro) José Guilherme Pereira Peixoto (IRD) José Mauro Granjeiro (Inmetro) Luiz Claudio Moreira Paschoal (Petrobras) Luis Fernado Rust (Inmetro) Luiz Silva Mello (PUC RJ) Marcos Nogueira Eberlin (Unicamp) Oleksii Kuznetsov (Inmetro) Regis Landim (Inmetro) Ricardo Carvalho (ON) Rodrigo Costa-Felix (Inmetro) Romeu José Daroda (Inmetro) Ruth Epsztejn (Inmetro) Valnei Smarçaro da Cunha (Inmetro) Valter Aibe (Inmetro) Waldemar Guilherme Kürten Ihlenfeld (PTB) Wanderley de Souza (UFRJ, Inmetro)

Electrical test prediction using hybrid metrology and machine learning

NASA Astrophysics Data System (ADS)

Breton, Mary; Chao, Robin; Muthinti, Gangadhara Raja; de la Peña, Abraham A.; Simon, Jacques; Cepler, Aron J.; Sendelbach, Matthew; Gaudiello, John; Emans, Susan; Shifrin, Michael; Etzioni, Yoav; Urenski, Ronen; Lee, Wei Ti

2017-03-01

Electrical test measurement in the back-end of line (BEOL) is crucial for wafer and die sorting as well as comparing intended process splits. Any in-line, nondestructive technique in the process flow to accurately predict these measurements can significantly improve mean-time-to-detect (MTTD) of defects and improve cycle times for yield and process learning. Measuring after BEOL metallization is commonly done for process control and learning, particularly with scatterometry (also called OCD (Optical Critical Dimension)), which can solve for multiple profile parameters such as metal line height or sidewall angle and does so within patterned regions. This gives scatterometry an advantage over inline microscopy-based techniques, which provide top-down information, since such techniques can be insensitive to sidewall variations hidden under the metal fill of the trench. But when faced with correlation to electrical test measurements that are specific to the BEOL processing, both techniques face the additional challenge of sampling. Microscopy-based techniques are sampling-limited by their small probe size, while scatterometry is traditionally limited (for microprocessors) to scribe targets that mimic device ground rules but are not necessarily designed to be electrically testable. A solution to this sampling challenge lies in a fast reference-based machine learning capability that allows for OCD measurement directly of the electrically-testable structures, even when they are not OCD-compatible. By incorporating such direct OCD measurements, correlation to, and therefore prediction of, resistance of BEOL electrical test structures is significantly improved. Improvements in prediction capability for multiple types of in-die electrically-testable device structures is demonstrated. To further improve the quality of the prediction of the electrical resistance measurements, hybrid metrology using the OCD measurements as well as X-ray metrology (XRF) is used. Hybrid metrology is the practice of combining information from multiple sources in order to enable or improve the measurement of one or more critical parameters. Here, the XRF measurements are used to detect subtle changes in barrier layer composition and thickness that can have second-order effects on the electrical resistance of the test structures. By accounting for such effects with the aid of the X-ray-based measurements, further improvement in the OCD correlation to electrical test measurements is achieved. Using both types of solution incorporation of fast reference-based machine learning on nonOCD-compatible test structures, and hybrid metrology combining OCD with XRF technology improvement in BEOL cycle time learning could be accomplished through improved prediction capability.

Design optimization of highly asymmetrical layouts by 2D contour metrology

NASA Astrophysics Data System (ADS)

Hu, C. M.; Lo, Fred; Yang, Elvis; Yang, T. H.; Chen, K. C.

2018-03-01

As design pitch shrinks to the resolution limit of up-to-date optical lithography technology, the Critical Dimension (CD) variation tolerance has been dramatically decreased for ensuring the functionality of device. One of critical challenges associates with the narrower CD tolerance for whole chip area is the proximity effect control on asymmetrical layout environments. To fulfill the tight CD control of complex features, the Critical Dimension Scanning Electron Microscope (CD-SEM) based measurement results for qualifying process window and establishing the Optical Proximity Correction (OPC) model become insufficient, thus 2D contour extraction technique [1-5] has been an increasingly important approach for complementing the insufficiencies of traditional CD measurement algorithm. To alleviate the long cycle time and high cost penalties for product verification, manufacturing requirements are better to be well handled at design stage to improve the quality and yield of ICs. In this work, in-house 2D contour extraction platform was established for layout design optimization of 39nm half-pitch Self-Aligned Double Patterning (SADP) process layer. Combining with the adoption of Process Variation Band Index (PVBI), the contour extraction platform enables layout optimization speedup as comparing to traditional methods. The capabilities of identifying and handling lithography hotspots in complex layout environments of 2D contour extraction platform allow process window aware layout optimization to meet the manufacturing requirements.

Chromatographic Separation of Cd from Plants via Anion-Exchange Resin for an Isotope Determination by Multiple Collector ICP-MS.

PubMed

Wei, Rongfei; Guo, Qingjun; Wen, Hanjie; Peters, Marc; Yang, Junxing; Tian, Liyan; Han, Xiaokun

2017-01-01

In this study, key factors affecting the chromatographic separation of Cd from plants, such as the resin column, digestion and purification procedures, were experimentally investigated. A technique for separating Cd from plant samples based on single ion-exchange chromatography has been developed, which is suitable for the high-precision analysis of Cd isotopes by multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The robustness of the technique was assessed by replicate analyses of Cd standard solutions and plant samples. The Cd yields of the whole separation process were higher than 95%, and the 114/110 Cd values of three Cd second standard solutions (Münster Cd, Spex Cd, Spex-1 Cd solutions) relative to the NIST SRM 3108 were measured accurately, which enabled the comparisons of Cd isotope results obtained in other laboratories. Hence, stable Cd isotope analyses represent a powerful tool for fingerprinting specific Cd sources and/or examining biogeochemical reactions in ecological and environmental systems.

CdTe1-x S x (x  ⩽  0.05) thin films synthesized by aqueous solution deposition and annealing

NASA Astrophysics Data System (ADS)

Pruzan, Dennis S.; Hahn, Carina E.; Misra, Sudhajit; Scarpulla, Michael A.

2017-11-01

While CdS thin films are commonly deposited from aqueous solutions, CdTe thin films are extremely difficult to deposit directly from aqueous solution. In this work, we report on polycrystalline CdTe1-x S x thin films synthesized via deposition from aqueous precursor solutions followed by annealing treatments and on their physical properties. The deposition method uses spin-coating of alternating Cd2+ and Te2- aqueous solutions and rinse steps to allow formation of the films but to shear off excess reactants and poorly-bonded solids. Films are then annealed in the presence of CdCl2 as is commonly done for CdTe photovoltaic absorber layers deposited by any means. Scanning electron microscopy (SEM) reveals low void fractions and grain sizes up to 4 µm and x-ray diffraction (XRD) shows that the films are primarily cubic CdTe1-x S x (x  ⩽  0.05) with random crystallographic orientation. Optical transmission yields bandgap absorption consistent with a CdTe1-x S x dilute alloy and low-temperature photoluminescence (PL) consists of an emission band centered at 1.35 eV consistent with donor-acceptor pair (DAP) transitions in CdTe1-x S x . Together, the crystalline quality and PL yield from films produced by this method represent an important step towards electroless, ligand-free solution processed CdTe and related alloy thin films suitable for optoelectronic device applications such as thin film heterojunction or nanodipole-based photovoltaics.

Recycling of CdTe photovoltaic waste

DOEpatents

Goozner, Robert E.; Long, Mark O.; Drinkard, Jr., William F.

1999-01-01

A method for extracting and reclaiming metals from scrap CdTe photovoltaic cells and manufacturing waste by leaching the waste with a leaching solution comprising nitric acid and water, skimming any plastic material from the top of the leaching solution, separating the glass substrate from the liquid leachate and electrolyzing the leachate to separate Cd from Te, wherein the Te is deposits onto a cathode while the Cd remains in solution.

Method and system for processing optical elements using magnetorheological finishing

DOEpatents

Menapace, Joseph Arthur; Schaffers, Kathleen Irene; Bayramian, Andrew James; Molander, William A

2012-09-18

A method of finishing an optical element includes mounting the optical element in an optical mount having a plurality of fiducials overlapping with the optical element and obtaining a first metrology map for the optical element and the plurality of fiducials. The method also includes obtaining a second metrology map for the optical element without the plurality of fiducials, forming a difference map between the first metrology map and the second metrology map, and aligning the first metrology map and the second metrology map. The method further includes placing mathematical fiducials onto the second metrology map using the difference map to form a third metrology map and associating the third metrology map to the optical element. Moreover, the method includes mounting the optical element in the fixture in an MRF tool, positioning the optical element in the fixture; removing the plurality of fiducials, and finishing the optical element.

Context-based virtual metrology

NASA Astrophysics Data System (ADS)

Ebersbach, Peter; Urbanowicz, Adam M.; Likhachev, Dmitriy; Hartig, Carsten; Shifrin, Michael

2018-03-01

Hybrid and data feed forward methodologies are well established for advanced optical process control solutions in highvolume semiconductor manufacturing. Appropriate information from previous measurements, transferred into advanced optical model(s) at following step(s), provides enhanced accuracy and exactness of the measured topographic (thicknesses, critical dimensions, etc.) and material parameters. In some cases, hybrid or feed-forward data are missed or invalid for dies or for a whole wafer. We focus on approaches of virtual metrology to re-create hybrid or feed-forward data inputs in high-volume manufacturing. We discuss missing data inputs reconstruction which is based on various interpolation and extrapolation schemes and uses information about wafer's process history. Moreover, we demonstrate data reconstruction approach based on machine learning techniques utilizing optical model and measured spectra. And finally, we investigate metrics that allow one to assess error margin of virtual data input.

Image-based overlay measurement using subsurface ultrasonic resonance force microscopy

NASA Astrophysics Data System (ADS)

Tamer, M. S.; van der Lans, M. J.; Sadeghian, H.

2018-03-01

Image Based Overlay (IBO) measurement is one of the most common techniques used in Integrated Circuit (IC) manufacturing to extract the overlay error values. The overlay error is measured using dedicated overlay targets which are optimized to increase the accuracy and the resolution, but these features are much larger than the IC feature size. IBO measurements are realized on the dedicated targets instead of product features, because the current overlay metrology solutions, mainly based on optics, cannot provide sufficient resolution on product features. However, considering the fact that the overlay error tolerance is approaching 2 nm, the overlay error measurement on product features becomes a need for the industry. For sub-nanometer resolution metrology, Scanning Probe Microscopy (SPM) is widely used, though at the cost of very low throughput. The semiconductor industry is interested in non-destructive imaging of buried structures under one or more layers for the application of overlay and wafer alignment, specifically through optically opaque media. Recently an SPM technique has been developed for imaging subsurface features which can be potentially considered as a solution for overlay metrology. In this paper we present the use of Subsurface Ultrasonic Resonance Force Microscopy (SSURFM) used for IBO measurement. We used SSURFM for imaging the most commonly used overlay targets on a silicon substrate and photoresist. As a proof of concept we have imaged surface and subsurface structures simultaneously. The surface and subsurface features of the overlay targets are fabricated with programmed overlay errors of +/-40 nm, +/-20 nm, and 0 nm. The top layer thickness changes between 30 nm and 80 nm. Using SSURFM the surface and subsurface features were successfully imaged and the overlay errors were extracted, via a rudimentary image processing algorithm. The measurement results are in agreement with the nominal values of the programmed overlay errors.

Transparent ohmic contacts for solution-processed, ultrathin CdTe solar cells

DOE PAGES

Kurley, J. Matthew; Panthani, Matthew G.; Crisp, Ryan W.; ...

2016-12-19

Recently, solution-processing became a viable route for depositing CdTe for use in photovoltaics. Ultrathin (~500 nm) solar cells have been made using colloidal CdTe nanocrystals with efficiencies exceeding 12% power conversion efficiency (PCE) demonstrated by using very simple device stacks. Further progress requires an effective method for extracting charge carriers generated during light harvesting. Here, we explored solution-based methods for creating transparent Ohmic contacts to the solution-deposited CdTe absorber layer and demonstrated molecular and nanocrystal approaches to Ohmic hole-extracting contacts at the ITO/CdTe interface. Furthermore, we used scanning Kelvin probe microscopy to further show how the above approaches improved carriermore » collection by reducing the potential drop under reverse bias across the ITO/CdTe interface. Other methods, such as spin-coating CdTe/A 2CdTe 2 (A = Na, K, Cs, N 2H 5), can be used in conjunction with current/light soaking to improve PCE further.« less

Detecting measurement outliers: remeasure efficiently

NASA Astrophysics Data System (ADS)

Ullrich, Albrecht

2010-09-01

Shrinking structures, advanced optical proximity correction (OPC) and complex measurement strategies continually challenge critical dimension (CD) metrology tools and recipe creation processes. One important quality ensuring task is the control of measurement outlier behavior. Outliers could trigger false positive alarm for specification violations impacting cycle time or potentially yield. Constant high level of outliers not only deteriorates cycle time but also puts unnecessary stress on tool operators leading eventually to human errors. At tool level the sources of outliers are natural variations (e.g. beam current etc.), drifts, contrast conditions, focus determination or pattern recognition issues, etc. Some of these can result from suboptimal or even wrong recipe settings, like focus position or measurement box size. Such outliers, created by an automatic recipe creation process faced with more complicated structures, would manifest itself rather as systematic variation of measurements than the one caused by 'pure' tool variation. I analyzed several statistical methods to detect outliers. These range from classical outlier tests for extrema, robust metrics like interquartile range (IQR) to methods evaluating the distribution of different populations of measurement sites, like the Cochran test. The latter suits especially the detection of systematic effects. The next level of outlier detection entwines additional information about the mask and the manufacturing process with the measurement results. The methods were reviewed for measured variations assumed to be normally distributed with zero mean but also for the presence of a statistically significant spatial process signature. I arrive at the conclusion that intelligent outlier detection can influence the efficiency and cycle time of CD metrology greatly. In combination with process information like target, typical platform variation and signature, one can tailor the detection to the needs of the photomask at hand. By monitoring the outlier behavior carefully, weaknesses of the automatic recipe creation process can be spotted.

Enhancing scatterometry CD signal-to-noise ratio for 1x logic and memory challenges

NASA Astrophysics Data System (ADS)

Shaughnessy, Derrick; Krishnan, Shankar; Wei, Lanhua; Shchegrov, Andrei V.

2013-04-01

The ongoing transition from 2D to 3D structures in logic and memory has led to an increased adoption of scatterometry CD (SCD) for inline metrology. However, shrinking device dimensions in logic and high aspect ratios in memory represent primary challenges for SCD and require a significant breakthrough in improving signal-to-noise performance. We present a report on the new generation of SCD technology, enabled by a new laser-driven plasma source. The developed light source provides several key advantages over conventional arc lamps typically used in SCD applications. The plasma color temperature of the laser driven source is considerably higher than available with arc lamps resulting in >5X increase in radiance in the visible and >10X increase in radiance in the DUV when compared to sources on previous generation SCD tools while maintaining or improving source intensity noise. This high radiance across such a broad spectrum allows for the use of a single light source from 190-1700nm. When combined with other optical design changes, the higher source radiance enables reduction of measurement box size of our spectroscopic ellipsometer from 45×45um box to 25×25um box without compromising signal to noise ratio. The benefits for 1×nm SCD metrology of the additional photons across the DUV to IR spectrum have been found to be greater than the increase in source signal to noise ratio would suggest. Better light penetration in Si and poly-Si has resulted in improved sensitivity and correlation breaking for critical parameters in 1xnm FinFET and HAR flash memory structures.

Computational metrology: enabling full-lot high-density fingerprint information without adding wafer metrology budget, and driving improved monitoring and process control

NASA Astrophysics Data System (ADS)

Kim, Hyun-Sok; Hyun, Min-Sung; Ju, Jae-Wuk; Kim, Young-Sik; Lambregts, Cees; van Rhee, Peter; Kim, Johan; McNamara, Elliott; Tel, Wim; Böcker, Paul; Oh, Nang-Lyeom; Lee, Jun-Hyung

2018-03-01

Computational metrology has been proposed as the way forward to resolve the need for increased metrology density, resulting from extending correction capabilities, without adding actual metrology budget. By exploiting TWINSCAN based metrology information, dense overlay fingerprints for every wafer can be computed. This extended metrology dataset enables new use cases, such as monitoring and control based on fingerprints for every wafer of the lot. This paper gives a detailed description, discusses the accuracy of the fingerprints computed, and will show results obtained in a DRAM HVM manufacturing environment. Also an outlook for improvements and extensions will be shared.

Incorporation of Cadmium and Nickel into Ferrite Spinel Solid Solution: X-ray Diffraction and X-ray Absorption Fine Structure Analyses.

PubMed

Su, Minhua; Liao, Changzhong; Chan, Tingshan; Shih, Kaimin; Xiao, Tangfu; Chen, Diyun; Kong, Lingjun; Song, Gang

2018-01-16

The feasibility of incorporating Cd and Ni in hematite was studied by investigating the interaction mechanism for the formation of Cd x Ni 1-x Fe 2 O 4 solid solutions (CNFs) from CdO, NiO, and α-Fe 2 O 3 . X-ray diffraction results showed that the CNFs crystallized into spinel structures with increasing lattice parameters as the Cd content in the precursors was increased. Cd 2+ ions were found to occupy the tetrahedral sites, as evidenced by Rietveld refinement and extended X-ray absorption fine structure analyses. The incorporation of Cd and Ni into ferrite spinel solid solution strongly relied on the processing parameters. The incorporation of Cd and Ni into the CNFs was greater at high x values (0.7 < x ≤ 1.0) than at low x values (0.0 ≤ x ≤ 0.7). A feasible treatment technique based on the investigated mechanism of CNF formation was developed, involving thermal treatment of waste sludge containing Cd and Ni. Both of these metals in the waste sludge were successfully incorporated into a ferrite spinel solid solution, and the concentrations of leached Cd and Ni from this solid solution were substantially reduced, stabilizing at low levels. This research offers a highly promising approach for treating the Cd and Ni content frequently encountered in electronic waste and its treatment residues.

Sodium chloride decreases cadmium accumulation and changes the response of metabolites to cadmium stress in the halophyte Carpobrotus rossii.

PubMed

Cheng, Miaomiao; Wang, Anan; Liu, Zhiqian; Gendall, Anthony R; Rochfort, Simone; Tang, Caixian

2018-05-18

Salinity affects the bioavailability of cadmium (Cd) in soils and Cd accumulation in plants, but the associated mechanisms remain unclear. This study aimed to assess the metabolic response to NaCl and Cd and the relationship between metabolites and Cd accumulation in the halophyte Carpobrotus rossii, which has potential for Cd phytoextraction. Plants were grown in nutrient solution with 0-400 mm NaCl in the presence of 5 or 15 µm Cd, with varied or constant solution Cd2+ activity. Plant growth and Cd uptake were measured, and the accumulation of peptides, and organic and amino acids in plant tissues were assessed. The addition of NaCl to Cd-containing solutions improved plant growth along with 70-87 % less shoot Cd accumulation, resulting from decreases in Cd root uptake and root-to-shoot translocation irrespective of Cd2+ activity in solutions. Moreover, Cd exposure increased the concentration of phytochelatins, which correlated positively with Cd concentrations in plants regardless of NaCl addition. In comparison, Cd inhibited the synthesis of organic acids in shoots and roots in the absence of NaCl, but increased it in shoots in the presence of NaCl. While Cd increased the concentrations of amino acids in plant shoots, the effect of NaCl on the synthesis of amino acids was inconsistent. Our data provide the first evidence that NaCl decreased Cd shoot accumulation in C. rossii by decreasing Cd root uptake and root-to-shoot translocation even under constant Cd2+ activity. The present study also supports the important role of peptides and organic acids, particular of phytochelatins, in Cd tolerance and accumulation although the changes of those metabolites was not the main reason for the decreased Cd accumulation.

Quantitative characterization of nanoparticle agglomeration within biological media

NASA Astrophysics Data System (ADS)

Hondow, Nicole; Brydson, Rik; Wang, Peiyi; Holton, Mark D.; Brown, M. Rowan; Rees, Paul; Summers, Huw D.; Brown, Andy

2012-07-01

Quantitative analysis of nanoparticle dispersion state within biological media is essential to understanding cellular uptake and the roles of diffusion, sedimentation, and endocytosis in determining nanoparticle dose. The dispersion of polymer-coated CdTe/ZnS quantum dots in water and cell growth medium with and without fetal bovine serum was analyzed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. Characterization by TEM of samples prepared by plunge freezing the blotted solutions into liquid ethane was sensitive to the dispersion state of the quantum dots and enabled measurement of agglomerate size distributions even in the presence of serum proteins where DLS failed. In addition, TEM showed a reduced packing fraction of quantum dots per agglomerate when dispersed in biological media and serum compared to just water, highlighting the effect of interactions between the media, serum proteins, and the quantum dots. The identification of a heterogeneous distribution of quantum dots and quantum dot agglomerates in cell growth medium and serum by TEM will enable correlation with the previously reported optical metrology of in vitro cellular uptake of this quantum dot dispersion. In this paper, we present a comparative study of TEM and DLS and show that plunge-freeze TEM provides a robust assessment of nanoparticle agglomeration state.

Toward reliable and repeatable automated STEM-EDS metrology with high throughput

NASA Astrophysics Data System (ADS)

Zhong, Zhenxin; Donald, Jason; Dutrow, Gavin; Roller, Justin; Ugurlu, Ozan; Verheijen, Martin; Bidiuk, Oleksii

2018-03-01

New materials and designs in complex 3D architectures in logic and memory devices have raised complexity in S/TEM metrology. In this paper, we report about a newly developed, automated, scanning transmission electron microscopy (STEM) based, energy dispersive X-ray spectroscopy (STEM-EDS) metrology method that addresses these challenges. Different methodologies toward repeatable and efficient, automated STEM-EDS metrology with high throughput are presented: we introduce the best known auto-EDS acquisition and quantification methods for robust and reliable metrology and present how electron exposure dose impacts the EDS metrology reproducibility, either due to poor signalto-noise ratio (SNR) at low dose or due to sample modifications at high dose conditions. Finally, we discuss the limitations of the STEM-EDS metrology technique and propose strategies to optimize the process both in terms of throughput and metrology reliability.

Synthesis and characterization of cadmium-calcium hydroxyapatite solid solutions

NASA Astrophysics Data System (ADS)

Zhao, Xin; Zhu, Yi-nian; Dai, Liu-qin

2014-06-01

A series of cadmium-calcium hydroxyapatite solid solutions was prepared by an aqueous precipitation method. By various means, the characterizations confirmed the formation of continuous solid solutions over all ranges of Cd/(Cd+Ca) atomic ratio. In the results, both lattice parameters a and c display slight deviations from Vegard's rule when the Cd/(Cd+Ca) atomic ratio is greater than 0.6. The particles change from smaller acicular to larger hexagonal columnar crystals as the Cd/(Cd+Ca) atomic ratio increases from 0-0.60 to 0.60-1.00. The area of the phosphate peak for symmetric P-O stretching decreases with the increase in Cd/(Cd+Ca) atomic ratio, and the peak disappears when the Cd/(Cd+Ca) atomic ratio is greater than 0.6; the two phosphate peaks of P-O stretching gradually merge together for the Cd/(Cd+Ca) atomic ratio near 0.60. These variations can be explained by a slight tendency of larger Cd ions to occupy M(2) sites and smaller Ca ions to prefer M(1) sites in the structure.

A novel patterning control strategy based on real-time fingerprint recognition and adaptive wafer level scanner optimization

NASA Astrophysics Data System (ADS)

Cekli, Hakki Ergun; Nije, Jelle; Ypma, Alexander; Bastani, Vahid; Sonntag, Dag; Niesing, Henk; Zhang, Linmiao; Ullah, Zakir; Subramony, Venky; Somasundaram, Ravin; Susanto, William; Matsunobu, Masazumi; Johnson, Jeff; Tabery, Cyrus; Lin, Chenxi; Zou, Yi

2018-03-01

In addition to lithography process and equipment induced variations, processes like etching, annealing, film deposition and planarization exhibit variations, each having their own intrinsic characteristics and leaving an effect, a `fingerprint', on the wafers. With ever tighter requirements for CD and overlay, controlling these process induced variations is both increasingly important and increasingly challenging in advanced integrated circuit (IC) manufacturing. For example, the on-product overlay (OPO) requirement for future nodes is approaching <3nm, requiring the allowable budget for process induced variance to become extremely small. Process variance control is seen as an bottleneck to further shrink which drives the need for more sophisticated process control strategies. In this context we developed a novel `computational process control strategy' which provides the capability of proactive control of each individual wafer with aim to maximize the yield, without introducing a significant impact on metrology requirements, cycle time or productivity. The complexity of the wafer process is approached by characterizing the full wafer stack building a fingerprint library containing key patterning performance parameters like Overlay, Focus, etc. Historical wafer metrology is decomposed into dominant fingerprints using Principal Component Analysis. By associating observed fingerprints with their origin e.g. process steps, tools and variables, we can give an inline assessment of the strength and origin of the fingerprints on every wafer. Once the fingerprint library is established, a wafer specific fingerprint correction recipes can be determined based on its processing history. Data science techniques are used in real-time to ensure that the library is adaptive. To realize this concept, ASML TWINSCAN scanners play a vital role with their on-board full wafer detection and exposure correction capabilities. High density metrology data is created by the scanner for each wafer and on every layer during the lithography steps. This metrology data will be used to obtain the process fingerprints. Also, the per exposure and per wafer correction potential of the scanners will be utilized for improved patterning control. Additionally, the fingerprint library will provide early detection of excursions for inline root cause analysis and process optimization guidance.

Organic matter and salinity modify cadmium soil (phyto)availability.

PubMed

Filipović, Lana; Romić, Marija; Romić, Davor; Filipović, Vilim; Ondrašek, Gabrijel

2018-01-01

Although Cd availability depends on its total concentration in soil, it is ultimately defined by the processes which control its mobility, transformations and soil solution speciation. Cd mobility between different soil fractions can be significantly affected by certain pedovariables such as soil organic matter (SOM; over formation of metal-organic complexes) and/or soil salinity (over formation of metal-inorganic complexes). Phytoavailable Cd fraction may be described as the proportion of the available Cd in soil which is actually accessible by roots and available for plant uptake. Therefore, in a greenhouse pot experiment Cd availability was observed in the rhizosphere of faba bean exposed to different levels of SOM, NaCl salinity (50 and 100mM) and Cd contamination (5 and 10mgkg -1 ). Cd availability in soil does not linearly follow its total concentration. Still, increasing soil Cd concentration may lead to increased Cd phytoavailability if the proportion of Cd 2+ pool in soil solution is enhanced. Reduced Cd (phyto)availability by raised SOM was found, along with increased proportion of Cd-DOC complexes in soil solution. Data suggest decreased Cd soil (phyto)availability with the application of salts. NaCl salinity affected Cd speciation in soil solution by promoting the formation of CdCl n 2-n complexes. Results possibly suggest that increased Cd mobility in soil does not result in its increased availability if soil adsorption capacity for Cd has not been exceeded. Accordingly, chloro-complex possibly operated just as a Cd carrier between different soil fractions and resulted only in transfer between solid phases and not in increased (phyto)availability. Copyright © 2017 Elsevier Inc. All rights reserved.

A model for trace metal sorption processes at the calcite surface: Adsorption of Cd2+ and subsequent solid solution formation

USGS Publications Warehouse

Davis, J.A.; Fuller, C.C.; Cook, A.D.

1987-01-01

The rate of Cd2+ sorption by calcite was determined as a function of pH and Mg2+ in aqueous solutions saturated with respect to calcite but undersaturated with respect to CdCO3. The sorption is characterized by two reaction steps, with the first reaching completion within 24 hours. The second step proceeded at a slow and nearly constant rate for at least 7 days. The rate of calcite recrystallization was also studied, using a Ca2+ isotopic exchange technique. Both the recrystallization rate of calcite and the rate of slow Cd2+ sorption decrease with increasing pH or with increasing Mg2+. The recrystallization rate could be predicted from the number of moles of Ca present in the hydrated surface layer. A model is presented which is consistent with the rates of Cd2+ sorption and Ca2+ isotopic exchange. In the model, the first step in Cd2+ sorption involves a fast adsorption reaction that is followed by diffusion of Cd2+ into a surface layer of hydrated CaCO3 that overlies crystalline calcite. Desorption of Cd2+ from the hydrated layer is slow. The second step is solid solution formation in new crystalline material, which grows from the disordered mixture of Cd and Ca carbonate in the hydrated surface layer. Calculated distribution coefficients for solid solutions formed at the surface are slightly greater than the ratio of equilibrium constants for dissolution of calcite and CdCO3, which is the value that would be expected for an ideal solid solution in equilibrium with the aqueous solution. ?? 1987.

Definition of a metrology servo-system for a solar imaging fourier transform spectrometer working in the far UV (IFTSUV)

NASA Astrophysics Data System (ADS)

Ruiz de Galarreta Fanju, C.; Philippon, A.; Bouzit, M.; Appourchaux, T.; Vial, J.-C.; Maillard, J.-P.; Lemaire, P.

2017-11-01

The understanding of the solar outer atmosphere requires a simultaneous combination of imaging and spectral observations concerning the far UV lines that arise from the high chromospheres up to the corona. These observations must be performed with enough spectral, spatial and temporal resolution to reveal the small atmospheric structures and to resolve the solar dynamics. An Imaging Fourier Transform Spectrometer working in the far-UV (IFTSUV, Figure 1) is an attractive instrumental solution to fulfill these requirements. However, due to the short wavelength, to preserve IFTSUV spectral precision and Signal to Noise Ratio (SNR) requires a high optical surface quality and a very accurate (linear and angular) metrology to maintain the optical path difference (OPD) during the entire scanning process by: optical path difference sampling trigger; and dynamic alignment for tip/tilt compensation (Figure 2).

Electrospinning of nanofibers from non-polymeric systems: polymer-free nanofibers from cyclodextrin derivatives

NASA Astrophysics Data System (ADS)

Celebioglu, Asli; Uyar, Tamer

2012-01-01

High molecular weight polymers and high polymer concentrations are desirable for the electrospinning of nanofibers since polymer chain entanglements and overlapping are important for uniform fiber formation. Hence, the electrospinning of nanofibers from non-polymeric systems such as cyclodextrins (CDs) is quite a challenge since CDs are cyclic oligosaccharides. Nevertheless, in this study, we have successfully achieved the electrospinning of nanofibers from chemically modified CDs without using a carrier polymer matrix. Polymer-free nanofibers were electrospun from three different CD derivatives, hydroxypropyl-β-cyclodextrin (HPβCD), hydroxypropyl-γ-cyclodextrin (HPγCD) and methyl-β-cyclodextrin (MβCD) in three different solvent systems, water, dimethylformamide (DMF) and dimethylacetamide (DMAc). We observed that the electrospinning of these CDs is quite similar to polymeric systems in which the solvent type, the solution concentration and the solution conductivity are some of the key factors for obtaining uniform nanofibers. Dynamic light scattering (DLS) measurements indicated that the presence of considerable CD aggregates and the very high solution viscosity were playing a key role for attaining nanofibers from CD derivatives without the use of any polymeric carrier. The electrospinning of CD solutions containing urea yielded no fibers but only beads or splashes since urea caused a notable destruction of the self-associated CD aggregates in their concentrated solutions. The structural, thermal and mechanical characteristics of the CD nanofibers were also investigated. Although the CD derivatives are amorphous small molecules, interestingly, we observed that these electrospun CD nanofibers/nanowebs have shown some mechanical integrity by which they can be easily handled and folded as a free standing material.

Wafer hot spot identification through advanced photomask characterization techniques

NASA Astrophysics Data System (ADS)

Choi, Yohan; Green, Michael; McMurran, Jeff; Ham, Young; Lin, Howard; Lan, Andy; Yang, Richer; Lung, Mike

2016-10-01

As device manufacturers progress through advanced technology nodes, limitations in standard 1-dimensional (1D) mask Critical Dimension (CD) metrics are becoming apparent. Historically, 1D metrics such as Mean to Target (MTT) and CD Uniformity (CDU) have been adequate for end users to evaluate and predict the mask impact on the wafer process. However, the wafer lithographer's process margin is shrinking at advanced nodes to a point that the classical mask CD metrics are no longer adequate to gauge the mask contribution to wafer process error. For example, wafer CDU error at advanced nodes is impacted by mask factors such as 3-dimensional (3D) effects and mask pattern fidelity on subresolution assist features (SRAFs) used in Optical Proximity Correction (OPC) models of ever-increasing complexity. These items are not quantifiable with the 1D metrology techniques of today. Likewise, the mask maker needs advanced characterization methods in order to optimize the mask process to meet the wafer lithographer's needs. These advanced characterization metrics are what is needed to harmonize mask and wafer processes for enhanced wafer hot spot analysis. In this paper, we study advanced mask pattern characterization techniques and their correlation with modeled wafer performance.

Radiation Characterization Summary: ACRR Cadmium-Polyethylene (CdPoly) Bucket Located in the Central Cavity on the 32-Inch Pedestal at the Core Centerline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parma, Edward J.; Naranjo, Gerald E.; Kaiser, Krista Irene

This document presents the facility-recommended characterization of the neutron, prompt gamma-ray, and delayed gamma-ray radiation fields in the Annular Core Research Reactor (ACRR) for the cadmium-polyethylene (CdPoly) bucket in the central cavity on the 32-inch pedestal at the core centerline. The designation for this environment is ACRR-CdPoly-CC-32-cl. The neutron, prompt gamma-ray, and delayed gamma-ray energy spectra, uncertainties, and covariance matrices are presented as well as radial and axial neutron and gamma-ray fluence profiles within the experiment area of the bucket. Recommended constants are given to facilitate the conversion of various dosimetry readings into radiation metrics desired by experimenters. Representative pulsemore » operations are presented with conversion examples. Acknowledgements The authors wish to thank the Annular Core Research Reactor staff and the Radiation Metrology Laboratory staff for their support of this work. Also thanks to Drew Tonigan for helping field the activation experiments in ACRR, David Samuel for helping to finalize the drawings and get the parts fabricated, and Elliot Pelfrey for preparing the active dosimetry plots.« less

Critical dimension control using ultrashort laser for improving wafer critical dimension uniformity

NASA Astrophysics Data System (ADS)

Avizemer, Dan; Sharoni, Ofir; Oshemkov, Sergey; Cohen, Avi; Dayan, Asaf; Khurana, Ranjan; Kewley, Dave

2015-07-01

Requirements for control of critical dimension (CD) become more demanding as the integrated circuit (IC) feature size specifications become tighter and tighter. Critical dimension control, also known as CDC, is a well-known laser-based process in the IC industry that has proven to be robust, repeatable, and efficient in adjusting wafer CD uniformity (CDU) [Proc. SPIE 6152, 615225 (2006)]. The process involves locally and selectively attenuating the deep ultraviolet light which goes through the photomask to the wafer. The input data for the CDC process in the wafer fab is typically taken from wafer CDU data, which is measured by metrology tools such as wafer-critical dimension-scanning electron microscopy (CD-SEM), wafer optical scatterometry, or wafer level CD (WLCD). The CD correction process uses the CDU data in order to create an attenuation correction contour, which is later applied by the in-situ ultrashort laser system of the CDC to locally change the transmission of the photomask. The ultrashort pulsed laser system creates small, partially scattered, Shade-In-Elements (also known as pixels) by focusing the laser beam inside the quartz bulk of the photomask. This results in the formation of a localized, intravolume, quartz modified area, which has a different refractive index than the quartz bulk itself. The CDC process flow for improving wafer CDU in a wafer fab with detailed explanations of the shading elements formation inside the quartz by the ultrashort pulsed laser is reviewed.

Leachate Properties and Cadmium Migration Through Freeze-thaw Treated Soil Columns.

PubMed

Xu, Meng; Zheng, Yue; Chen, Weiwei; Mao, Na; Guo, Ping

2017-01-01

Soil column leaching experiments were conducted to study the effects of multiple freeze-thaw cycles on the vertical migration of cadmium (Cd). Three Cd-spiked leaching solutions of different properties were derived from snowmelt, sludge, and straw, designated as B, W and J, respectively. The leaching solutions varied in dissolved organic matter (DOM) concentrations in the order of J > W > B. Changes in leachate properties and Cd concentration were observed. The results showed that pH values of all the leachate solutions through freeze-thaw treated soil columns were higher than those of leachates through unfrozen soils. However, electrical conductivity (EC) values decreased compared with leachates in unfrozen treated soil columns. Although the concentrations of DOM in leachate solutions had no evident differences between the freeze-thaw and unfrozen treated soil columns, the concentrations of DOM in the leachate solutions B, W and J were different. Freeze-thaw cycles resulted in increased concentrations of Cd in the leachate solutions in the order J > W > B, and promoted a deeper migration of Cd in the soil columns. Thus, it was shown that freeze-thaw cycles may increase the risk of groundwater pollution by Cd.

Optical metrology for Starlight Separated Spacecraft Stellar Interferometry Mission

NASA Technical Reports Server (NTRS)

Dubovitsky, S.; Lay, O. P.; Peters, R. D.; Abramovici, A.; Asbury, C. G.; Kuhnert, A. C.; Mulder, J. L.

2002-01-01

We describe a high-precision inter-spacecraft metrology system designed for NASA 's StarLight mission, a space-based separated-spacecraft stellar interferometer. It consists of dual-target linear metrology, based on a heterodyne interferometer with carrier phase modulation, and angular metrology designed to sense the pointing of the laser beam and provides bearing information. The dual-target operation enables one metrology beam to sense displacement of two targets independently. We present the current design, breadboard implementation of the Metrology Subsystem in a stellar interferometer testbed and the present state of development of flight qualifiable subsystem components.

Metrology Arrangement for Measuring the Positions of Mirrors of a Submillimeter Telescope

NASA Technical Reports Server (NTRS)

Abramovici, Alex; Bartman, Randall K.

2011-01-01

The position of the secondary mirror of a submillimeter telescope with respect to the primary mirror needs to be known .0.03 mm in three dimensions. At the time of this reporting, no convenient, reasonably priced arrangement that offers this capability exists. The solution proposed here relies on measurement devices developed and deployed for the GeoSAR mission, and later adapted for the ISAT (Innovative Space Based Radar Antenna Technology) demonstration. The measurement arrangement consists of four metrology heads, located on an optical bench, attached to the secondary mirror. Each metrology head has a dedicated target located at the edge of the primary mirror. One laser beam, launched from the head and returned by the target, is used to measure distance. Another beam, launched from a beacon on the target, is monitored by the metrology head and generates a measurement of the target position in the plane perpendicular to the laser beam. A 100-MHz modulation is carried by a collimated laser beam. The relevant wavelength is the RF one, 3 m, divided by two, because the light carries it to the target and back. The phase change due to travel to the target and back is measured by timing the zero-crossing of the RF modulation, using a 100-MHz clock. In order to obtain good resolution, the 100-MHz modulation signal is down-converted to 1 kHz. Then, the phase change corresponding to the round-trip to the target is carried by a 1-kHz signal. Since the 100-MHz clock beats 100,000 times during one period of the 1-kHz signal, the least-significant-bit (LSB) resolution is LSB = 0.015 mm.

Optical monitoring of protein crystal growth

NASA Technical Reports Server (NTRS)

Choudry, A.

1988-01-01

The possibility of using various optical techniques for detecting the onset of nucleation in protein crystal growth was investigated. Direct microscopy, general metrologic techniques, light scattering, ultraviolet absorption, and interferometry are addressed along with techniques for determining pH value. The necessity for collecting basic data on the optical properties of the growth solution as a prerequisite to the evaluation of monitoring techniques is pointed out.

Effects of the pH and Concentration on the Stability of Standard Solutions of Proteinogenic Amino Acid Mixtures.

PubMed

Kato, Megumi; Yamazaki, Taichi; Kato, Hisashi; Yamanaka, Noriko; Takatsu, Akiko; Ihara, Toshihide

2017-01-01

To prepare metrologically traceable amino acid mixed standard solutions, it is necessary to determine the stability of each amino acid present in the mixed solutions. In the present study, we prepared amino acid mixed solutions using certified reference standards of 17 proteinogenic amino acids, and examined the stability of each of these amino acids in 0.1 N HCl. We found that the concentration of glutamic acid decreased significantly during storage. LC/MS analysis indicated that the instability of glutamic acid was due to the partial degradation of glutamic acid to pyroglutamic acid in 0.1 N HCl. Using accelerated degradation tests, we investigated several solvent compositions to improve the stability of glutamic acid in amino acid mixed solution, and determined that the change of the pH by diluting the mixed solution improved the stability of glutamic acid.

Fate of cadmium at the soil-solution interface: a thermodynamic study as influenced by varying pH at South 24 Parganas, West Bengal, India.

PubMed

Karak, Tanmoy; Paul, Ranjit Kumar; Das, Sampa; Das, Dilip K; Dutta, Amrit Kumar; Boruah, Romesh K

2015-11-01

A study on the sorption kinetics of Cd from soil solution to soils was conducted to assess the persistence of Cd in soil solution as it is related to the leaching, bioavailability, and potential toxicity of Cd. The kinetics of Cd sorption on two non-contaminated alkaline soils from Canning (22° 18' 48.02″ N and 88° 39' 29.0″ E) and Lakshmikantapur (22° 06' 16.61″ N and 88° 19' 08.66″ E) of South 24 Parganas, West Bengal, India, were studied using conventional batch experiment. The variable soil suspension parameters were pH (4.00, 6.00, 8.18, and 9.00), temperatures (308, 318, and 328 K) and Cd concentrations (5-100 mg L(-1)). The average rate coefficient (kavg) and half-life (t1/2) values indicate that the persistence of Cd in soil solution is influenced by both temperature and soil suspension pH. The concentration of Cd in soil solution decreases with increase of temperature; therefore, Cd sorption on the soil-solution interface is an endothermic one. Higher pH decreases the t 1/2 of Cd in soil solution, indicating that higher pH (alkaline) is not a serious concern in Cd toxicity than lower pH (acidic). Based on the energy of activation (Ea) values, Cd sorption in acidic pH (14.76±0.29 to 64.45±4.50 kJ mol(-1)) is a surface control phenomenon and in alkaline pH (9.33±0.09 to 44.60±2.01 kJ mol(-1)) is a diffusion control phenomenon The enthalpy of activation (ΔH∓) values were found to be between 7.28 and 61.73 kJ mol(-1). Additionally, higher positive energy of activation (ΔG∓) values (46.82±2.01 to 94.47±2.36 kJ mol(-1)) suggested that there is an energy barrier for product formation.

Choosing a CD-ROM Network Solution.

ERIC Educational Resources Information Center

Doering, David

1996-01-01

Discusses issues to consider in selecting a CD-ROM network solution, including throughput (speed of data delivery), security, access, servers, key features, training, jukebox support, documentation, and licenses. Reviews software products offered by Novell, Around Technology, Micro Design, Smart Storage, Microtest, Meridian, CD-Connection,…

Mask Design for the Space Interferometry Mission Internal Metrology

NASA Technical Reports Server (NTRS)

Marx, David; Zhao, Feng; Korechoff, Robert

2005-01-01

This slide presentation reviews the mask design used for the internal metrology of the Space Interferometry Mission (SIM). Included is information about the project, the method of measurements with SIM, the internal metrology, numerical model of internal metrology, wavefront examples, performance metrics, and mask design

Cadmium dynamics in soil pore water and uptake by rice: Influences of soil-applied selenite with different water managements.

PubMed

Wan, Yanan; Camara, Aboubacar Younoussa; Yu, Yao; Wang, Qi; Guo, Tianliang; Zhu, Lina; Li, Huafen

2018-05-11

Cadmium (Cd) in rice grains is a potential threat to human health. This study investigated the effects of selenite fertilisation (0 mg kg -1 , 0.5 mg kg -1 , and 1.0 mg kg -1 ) on soil solution Cd dynamics and rice uptake. Rice was grown in two Cd-contaminated soils in Jiangxi and Hunan Provinces under two different sets of conditions: aerobic and flooded. The experiments were conducted in pots. The plants were harvested at the seedling stage and at maturity to determine their Cd levels. Soil solutions were also extracted during the growing season to monitor Cd dynamics. The results showed that in the Jiangxi soil (pH 5.25), Cd concentrations in the soil solutions, seedlings, and mature rice plants were higher under aerobic than under flooded water management conditions. In the Hunan soil (pH 7.26), however, flooding decreased Cd levels in the rice seedlings but not in mature plants. Selenite additions to the Hunan soil decreased Cd concentrations in the soil solutions and in the mature rice plants. These effects were not observed for the solutions or the plants from Jiangxi soil amended with selenite. Relative to the control treatment, 0.5 mg kg -1 selenite decreased the rice grain Cd content by 45.2% and 67.7% under aerobic and flooding conditions, respectively. The results demonstrated that water management regimes affected rice Cd uptake more effectively in Jiangxi than in Hunan soil, whereas selenite addition was more effective in Hunan than in Jiangxi soil. Selenite addition was also more effective at reducing rice grain Cd levels when it was applied under flooding than under aerobic conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Phytoextraction of cadmium by Ipomoea aquatica (water spinach) in hydroponic solution: effects of cadmium speciation.

PubMed

Wang, Kai-Sung; Huang, Lung-Chiu; Lee, Hong-Shen; Chen, Pai-Ye; Chang, Shih-Hsien

2008-06-01

Phytoextraction is a promising technique to remediate heavy metals from contaminated wastewater. However, the interactions of multi-contaminants are not fully clear. This study employed cadmium, Triton X-100 (TX-100), and EDTA to investigate their interactions on phytotoxicity and Cd phytoextraction of Ipomoea aquatica (water spinach) in simulated wastewater. The Cd speciation was estimated by a chemical equilibrium model and MINEQL+. Statistic regression was applied to evaluate Cd speciation on Cd uptake in shoots and stems of I. aquatica. Results indicated that the root length was a more sensitive parameter than root weight and shoot weight. Root elongation was affected by Cd in the Cd-EDTA solution and TX-100 in the Cd-TX-100 solution. Both the root length and the root biomass were negatively correlated with the total soluble Cd ions. In contrast, Cd phytoextraction of I. aquatic was correlated with the aqueous Cd ions in the free and complex forms rather than in the chelating form. Additionally, the high Cd bioconcentration factors of I. aquatica (375-2227 l kg(-1) for roots, 45-144 l kg(-1) for shoots) imply that I. aquatica is a potential aquatic plant to remediate Cd-contaminated wastewater.

Phytoavailability and bioaccumulation of cadmium in Duckweed plants (Spirodela polyrhiza L. Schleid)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sajwan, K.S.; Ornes, W.H.

1994-06-01

The aquatic vascular plant Duckweed (Spirodela polyhiza L. Schleid) was investigated as a potential biological filter for wastewater Cd removal. Duckweed plants were grown in and harvested weekly from 0.10 M Hoagland nutrient solutions containing 0.04-7.63 [mu]g Cd/mL. Dry weights of plants significantly decreased when exposed to 7.63 [mu]g Cd/mL. For both the 1.03 and 7.63 [mu]g Cd/mL treatments the greatest Cd accumulation in plants occurred during week 1 and decreased through week 4. It was also interesting to note that tissue P was observed to be suppressed for one week at higher Cd treatments, and thereafter increased as themore » tissue Cd levels decreased. Frond production was decreased by the lowest Cd treatments by the second week. These results suggest that Duckweed can tolerate and accumulate Cd for one week even when exposed to 7.63 [mu]g Cd/mL. However, after one week the plants needed to be removed from the Cd solution to avoid tissue Cd loss and to achieve maximum removal from solution. 24 refs., 4 tabs.« less

Energy dispersive X-ray fluorescence determination of cadmium in uranium matrix using Cd Kα line excited by continuum

NASA Astrophysics Data System (ADS)

Dhara, Sangita; Misra, N. L.; Aggarwal, S. K.; Venugopal, V.

2010-06-01

An energy dispersive X-ray fluorescence method for determination of cadmium (Cd) in uranium (U) matrix using continuum source of excitation was developed. Calibration and sample solutions of cadmium, with and without uranium were prepared by mixing different volumes of standard solutions of cadmium and uranyl nitrate, both prepared in suprapure nitric acid. The concentration of Cd in calibration solutions and samples was in the range of 6 to 90 µg/mL whereas the concentration of Cd with respect to U ranged from 90 to 700 µg/g of U. From the calibration solutions and samples containing uranium, the major matrix uranium was selectively extracted using 30% tri-n-butyl phosphate in dodecane. Fixed volumes (1.5 mL) of aqueous phases thus obtained were taken directly in specially designed in-house fabricated leak proof Perspex sample cells for the energy dispersive X-ray fluorescence measurements and calibration plots were made by plotting Cd Kα intensity against respective Cd concentration. For the calibration solutions not having uranium, the energy dispersive X-ray fluorescence spectra were measured without any extraction and Cd calibration plots were made accordingly. The results obtained showed a precision of 2% (1 σ) and the results deviated from the expected values by < 4% on average.

Stable supersaturated aqueous solutions of silatecan 7-t-butyldimethylsilyl-10-hydroxycamptothecin via chemical conversion in the presence of a chemically modified beta-cyclodextrin.

PubMed

Xiang, Tian-Xiang; Anderson, Bradley D

2002-08-01

A method for obtaining clear supersaturated aqueous solutions for parenteral administration of the poorly soluble experimental anti-cancer drug silatecan 7-t-butyldimethylsilyl-10-hydroxycamptothecin (DB-67) has been developed. Equilibrium solubilities of DB-67 were determined in various solvents and pH values, and in the presence of chemically modified water-soluble beta-cyclodextrins. The stoichiometry and binding constants for complexes of the lactone form of DB-67 and its ring-opened carboxylate with sulfobutyl ether and 2-hydroxypropyl substituted beta-cyclodextrins (SBE-CD and HP-CD) were obtained by solubility and circular dichroism spectroscopy, respectively. Kinetics for the reversible ring-opening of DB-67 in aqueous solution and for lactone precipitation were determined by HPLC with UV detection. Solubilities of DB-67 lactone in various injectable solvent systems were found to be at least one order of magnitude below the target concentration (2 mg/ml). DB-67 forms inclusion complexes with SBE-CD and HP-CD but the solubilization attainable is substantially less than the target concentration. Slow addition of DB-67/ DMSO into 22.2% (w/v) SBE-CD failed to yield stable supersaturated solutions due to precipitation. Stable supersatured solutions were obtained, however, by mixing a concentrated alkaline aqueous solution of DB-67 carboxylate with an acidified 22.2% (w/v) SBE-CD solution. Ring-closure yielded supersaturated solutions that could be lyophilized and reconstituted to clear, stable, supersaturated solutions. The method developed provides an alternative to colloidal dispersions (e.g., liposomal suspensions, emulsions, etc.) for parenteral administration of lipophilic camptothecin analogs.

Hylemetry versus Biometry: a new method to certificate the lithography authenticity

NASA Astrophysics Data System (ADS)

Schirripa Spagnolo, Giuseppe; Cozzella, Lorenzo; Simonetti, Carla

2011-06-01

When we buy an artwork object a certificate of authenticity contain specific details about the artwork. Unfortunately, these certificates are often exchanged between similar artworks: the same document is supplied by the seller to certificate the originality. In this way the buyer will have a copy of an original certificate to attest that the "not original artwork" is an original one. A solution for this problem would be to insert a system that links together the certificate and a specific artwork. To do this it is necessary, for a single artwork, to find unique, unrepeatable, and unchangeable characteristics. In this paper we propose a new lithography certification based on the color spots distribution, which compose the lithography itself. Due to the high resolution acquisition media available today, it is possible using analysis method typical of speckle metrology. In particular, in verification phase it is only necessary acquiring the same portion of lithography, extracting the verification information, using the private key to obtain the same information from the certificate and confronting the two information using a comparison threshold. Due to the possible rotation and translation it is applied image correlation solutions, used in speckle metrology, to determine translation and rotation error and correct allow to verifying extracted and acquired images in the best situation, for granting correct originality verification.

Evaluation of 3D metrology potential using a multiple detector CDSEM

NASA Astrophysics Data System (ADS)

Hakii, Hidemitsu; Yonekura, Isao; Nishiyama, Yasushi; Tanaka, Keishi; Komoto, Kenji; Murakawa, Tsutomu; Hiroyama, Mitsuo; Shida, Soichi; Kuribara, Masayuki; Iwai, Toshimichi; Matsumoto, Jun; Nakamura, Takayuki

2012-06-01

As feature sizes of semiconductor device structures have continuously decreased, needs for metrology tools with high precision and excellent linearity over actual pattern sizes have been growing. And it has become important to measure not only two-dimensional (2D) but also three-dimensional (3D) shapes of patterns at 22 nm node and beyond. To meet requirements for 3D metrology capabilities, various pattern metrology tools have been developed. Among those, we assume that CDSEM metrology is the most qualified candidate in the light of its non-destructive, high throughput measurement capabilities that are expected to be extended to the much-awaited 3D metrology technology. On the basis of this supposition, we have developed the 3D metrology system, in which side wall angles and heights of photomask patterns can be measured with high accuracy through analyzing CDSEM images generated by multi-channel detectors. In this paper, we will discuss our attempts to measure 3D shapes of defect patterns on a photomask by using Advantest's "Multi Vision Metrology SEM" E3630 (MVM-SEM' E3630).

Experimental Demonstration of Higher Precision Weak-Value-Based Metrology Using Power Recycling

NASA Astrophysics Data System (ADS)

Wang, Yi-Tao; Tang, Jian-Shun; Hu, Gang; Wang, Jian; Yu, Shang; Zhou, Zong-Quan; Cheng, Ze-Di; Xu, Jin-Shi; Fang, Sen-Zhi; Wu, Qing-Lin; Li, Chuan-Feng; Guo, Guang-Can

2016-12-01

The weak-value-based metrology is very promising and has attracted a lot of attention in recent years because of its remarkable ability in signal amplification. However, it is suggested that the upper limit of the precision of this metrology cannot exceed that of classical metrology because of the low sample size caused by the probe loss during postselection. Nevertheless, a recent proposal shows that this probe loss can be reduced by the power-recycling technique, and thus enhance the precision of weak-value-based metrology. Here we experimentally realize the power-recycled interferometric weak-value-based beam-deflection measurement and obtain the amplitude of the detected signal and white noise by discrete Fourier transform. Our results show that the detected signal can be strengthened by power recycling, and the power-recycled weak-value-based signal-to-noise ratio can surpass the upper limit of the classical scheme, corresponding to the shot-noise limit. This work sheds light on higher precision metrology and explores the real advantage of the weak-value-based metrology over classical metrology.

Role of root exudates in dissolution of Cd containing iron oxides

NASA Astrophysics Data System (ADS)

Rosenfeld, C.; Martinez, C. E.

2011-12-01

Dissolved organic matter (DOM) in the rhizosphere contains organic acids, amino acids and more complex organic molecules that can substantially impact the solubility of soil solid phases. Plant roots and soil microorganisms contribute a large fraction of these organic compounds to DOM, potentially accelerating the transfer of solid phase elements into solution. In highly contaminated soils, heavy metals such as Cd are commonly found coprecipitated with common minerals (e.g. iron oxides). Introducing or changing vegetation on these contaminated soils may increase DOM levels in the soil pore fluids and thus enhance the biological and chemical weathering of soil minerals. Here, we investigate the role of root exudates on mineral dissolution and Cd mobility in contaminated soils. We hypothesize that plant exudates containing nitrogen and sulfur functional groups will dissolve Cd-containing mineral phases to a greater extent than exudates containing only oxygen functional groups, resulting in higher Cd concentrations in solution. Two different iron oxide mineral phases were utilized in a laboratory-scale model study system investigating the effects of low molecular weight, oxygen-, nitrogen-, and sulfur-containing organic compounds on mineral dissolution. Goethite (α-FeOOH) was synthesized in the laboratory with 0, 2.4, 5, and 100 theoretical mol% Cd, and franklinite (ZnFe2O4) was prepared with 0, 10, and 25 theoretical mol% Cd. Phase identity of all minerals was verified with X-ray diffraction (XRD). All minerals were reacted with 0.01 mM solutions containing one of four different organic ligands (oxalic acid, citric acid, histidine or cysteine) and aliquots of these solutions were sampled periodically over 40 days. Results from solution samples suggest that oxalic acid, citric acid, and histidine consistently increase mineral dissolution relative to the control (no organic compound present) while cysteine consistently inhibits dissolution relative to the control in all minerals. Increasing Cd substitution in the franklinite resulted in increased release of Fe and Zn to solution in the presence of these organic compounds, while increasing Cd substitution in the goethite generally limited Fe release to solution. In the case of cysteine, sulfur concentrations in solution decrease over time in the presence of Cd-containing minerals, indicating strong binding of the cysteine compound to the mineral surface, inhibiting Cd dissolution from the minerals. Our work indicates that amino acids present in biological soil exudates, in addition to organic acids, may have substantial impacts on iron oxide dissolution in soils, altering the availability of both bioessential (e.g., Fe and Zn) and non-essential, or potentially toxic, (e.g., Cd) elements.

Effects of the addition and aging of humic acid-based amendments on the solubility of Cd in soil solution and its accumulation in rice.

PubMed

Yu, Yao; Wan, Yanan; Camara, Aboubacar Younoussa; Li, Huafen

2018-04-01

Humic substances can reduce mobility and bio-accessibility of Cd in soil and therefore inhibit its uptake by rice, which is a major source of human Cd intake. Yet, the effects of aging humic substances are not fully understood. A rice pot experiment was conducted to evaluate the effects of humic acid-based amendments on the mobility of Cd in soil solution and its uptake by rice when amendments were freshly added or aged for 130 d. The results showed that the aged and the unaged amendments generally decreased Cd concentration in soil solution, but the effect declined with time. Unaged HA-K (humic-potassium) reduced Cd concentration by 88% for the first sampling, but this dropped to 46% for the last sampling, compared to that of the control. All amendments, whether aged or not, reduced the content of Cd in rice seedlings, as well as in mature plants. Aged and unaged woody peat reduced the Cd content in seedlings by 79% and in grains by 70%, respectively. Aging of amendments caused lower pH and higher Cd concentration in the soil solution for all amendments and accordingly, the Cd content in rice seedlings or each part of mature plants in the aged group was higher than that of the unaged group. The applied amendments might reduce the solubility of Cd through the alteration in soil pH, and thus inhibit the uptake of Cd by rice, but the effects diminished with aging. Copyright © 2018 Elsevier Ltd. All rights reserved.

Penetration enhancement of ibuprofen from supersaturated solutions through human skin.

PubMed

Iervolino, M; Cappello, B; Raghavan, S L; Hadgraft, J

2001-01-05

Systematic investigations on the diffusion of ibuprofen (IBU) from supersaturated solutions through human epidermis are reported. Significant flux enhancement was obtained from supersaturated solutions compared to the saturated solution. Hydroxypropyl methylcellulose (HPMC), when used as an additive was found to be effective in maintaining the high activity state at high degrees of saturation (DS). The increase in the flux was proportional to the DS. In the presence of 2-hydroxypropyl-beta-cyclodextrin (CD) at DS 2 and 3 a lower flux was observed compared to HPMC. At DS 5 a higher flux enhancement was found suggesting that CD might act as a penetration enhancer at certain CD/drug ratios. Studies on the mechanism of stabilisation of HPMC and CD on IBU crystallisation from supersaturated systems showed that HPMC acts as a growth inhibitor and habit modifier whereas CD does not influence the crystallisation process.

Advanced in-production hotspot prediction and monitoring with micro-topography

NASA Astrophysics Data System (ADS)

Fanton, P.; Hasan, T.; Lakcher, A.; Le-Gratiet, B.; Prentice, C.; Simiz, J.-G.; La Greca, R.; Depre, L.; Hunsche, S.

2017-03-01

At 28nm technology node and below, hot spot prediction and process window control across production wafers have become increasingly critical to prevent hotspots from becoming yield-limiting defects. We previously established proof of concept for a systematic approach to identify the most critical pattern locations, i.e. hotspots, in a reticle layout by computational lithography and combining process window characteristics of these patterns with across-wafer process variation data to predict where hotspots may become yield impacting defects [1,2]. The current paper establishes the impact of micro-topography on a 28nm metal layer, and its correlation with hotspot best focus variations across a production chip layout. Detailed topography measurements are obtained from an offline tool, and pattern-dependent best focus (BF) shifts are determined from litho simulations that include mask-3D effects. We also establish hotspot metrology and defect verification by SEM image contour extraction and contour analysis. This enables detection of catastrophic defects as well as quantitative characterization of pattern variability, i.e. local and global CD uniformity, across a wafer to establish hotspot defect and variability maps. Finally, we combine defect prediction and verification capabilities for process monitoring by on-product, guided hotspot metrology, i.e. with sampling locations being determined from the defect prediction model and achieved prediction accuracy (capture rate) around 75%

Advanced overlay analysis through design based metrology

NASA Astrophysics Data System (ADS)

Ji, Sunkeun; Yoo, Gyun; Jo, Gyoyeon; Kang, Hyunwoo; Park, Minwoo; Kim, Jungchan; Park, Chanha; Yang, Hyunjo; Yim, Donggyu; Maruyama, Kotaro; Park, Byungjun; Yamamoto, Masahiro

2015-03-01

As design rule shrink, overlay has been critical factor for semiconductor manufacturing. However, the overlay error which is determined by a conventional measurement with an overlay mark based on IBO and DBO often does not represent the physical placement error in the cell area. The mismatch may arise from the size or pitch difference between the overlay mark and the cell pattern. Pattern distortion caused by etching or CMP also can be a source of the mismatch. In 2014, we have demonstrated that method of overlay measurement in the cell area by using DBM (Design Based Metrology) tool has more accurate overlay value than conventional method by using an overlay mark. We have verified the reproducibility by measuring repeatable patterns in the cell area, and also demonstrated the reliability by comparing with CD-SEM data. We have focused overlay mismatching between overlay mark and cell area until now, further more we have concerned with the cell area having different pattern density and etch loading. There appears a phenomenon which has different overlay values on the cells with diverse patterning environment. In this paper, the overlay error was investigated from cell edge to center. For this experiment, we have verified several critical layers in DRAM by using improved(Better resolution and speed) DBM tool, NGR3520.

Image-based overlay and alignment metrology through optically opaque media with sub-surface probe microscopy

NASA Astrophysics Data System (ADS)

van Es, Maarten H.; Mohtashami, Abbas; Piras, Daniele; Sadeghian, Hamed

2018-03-01

Nondestructive subsurface nanoimaging through optically opaque media is considered to be extremely challenging and is essential for several semiconductor metrology applications including overlay and alignment and buried void and defect characterization. The current key challenge in overlay and alignment is the measurement of targets that are covered by optically opaque layers. Moreover, with the device dimensions moving to the smaller nodes and the issue of the so-called loading effect causing offsets between between targets and product features, it is increasingly desirable to perform alignment and overlay on product features or so-called on-cell overlay, which requires higher lateral resolution than optical methods can provide. Our recently developed technique known as SubSurface Ultrasonic Resonance Force Microscopy (SSURFM) has shown the capability for high-resolution imaging of structures below a surface based on (visco-)elasticity of the constituent materials and as such is a promising technique to perform overlay and alignment with high resolution in upcoming production nodes. In this paper, we describe the developed SSURFM technique and the experimental results on imaging buried features through various layers and the ability to detect objects with resolution below 10 nm. In summary, the experimental results show that the SSURFM is a potential solution for on-cell overlay and alignment as well as detecting buried defects or voids and generally metrology through optically opaque layers.

Dimensional metrology of lab-on-a-chip internal structures: a comparison of optical coherence tomography with confocal fluorescence microscopy.

PubMed

Reyes, D R; Halter, M; Hwang, J

2015-07-01

The characterization of internal structures in a polymeric microfluidic device, especially of a final product, will require a different set of optical metrology tools than those traditionally used for microelectronic devices. We demonstrate that optical coherence tomography (OCT) imaging is a promising technique to characterize the internal structures of poly(methyl methacrylate) devices where the subsurface structures often cannot be imaged by conventional wide field optical microscopy. The structural details of channels in the devices were imaged with OCT and analyzed with an in-house written ImageJ macro in an effort to identify the structural details of the channel. The dimensional values obtained with OCT were compared with laser-scanning confocal microscopy images of channels filled with a fluorophore solution. Attempts were also made using confocal reflectance and interferometry microscopy to measure the channel dimensions, but artefacts present in the images precluded quantitative analysis. OCT provided the most accurate estimates for the channel height based on an analysis of optical micrographs obtained after destructively slicing the channel with a microtome. OCT may be a promising technique for the future of three-dimensional metrology of critical internal structures in lab-on-a-chip devices because scans can be performed rapidly and noninvasively prior to their use. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Metrological challenges for measurements of key climatological observables: Oceanic salinity and pH, and atmospheric humidity. Part 1: Overview.

PubMed

Feistel, R; Wielgosz, R; Bell, S A; Camões, M F; Cooper, J R; Dexter, P; Dickson, A G; Fisicaro, P; Harvey, A H; Heinonen, M; Hellmuth, O; Kretzschmar, H-J; Lovell-Smith, J W; McDougall, T J; Pawlowicz, R; Ridout, P; Seitz, S; Spitzer, P; Stoica, D; Wolf, H

2016-02-01

Water in its three ambient phases plays the central thermodynamic role in the terrestrial climate system. Clouds control Earth's radiation balance, atmospheric water vapour is the strongest "greenhouse" gas, and non-equilibrium relative humidity at the air-sea interface drives evaporation and latent heat export from the ocean. On climatic time scales, melting ice caps and regional deviations of the hydrological cycle result in changes of seawater salinity, which in turn may modify the global circulation of the oceans and their ability to store heat and to buffer anthropogenically produced carbon dioxide. In this paper, together with three companion articles, we examine the climatologically relevant quantities ocean salinity, seawater pH and atmospheric relative humidity, noting fundamental deficiencies in the definitions of those key observables, and their lack of secure foundation on the International System of Units, the SI. The metrological histories of those three quantities are reviewed, problems with their current definitions and measurement practices are analysed, and options for future improvements are discussed in conjunction with the recent seawater standard TEOS-10. It is concluded that the International Bureau of Weights and Measures, BIPM, in cooperation with the International Association for the Properties of Water and Steam, IAPWS, along with other international organisations and institutions, can make significant contributions by developing and recommending state-of-the-art solutions for these long standing metrological problems in climatology.

On the evaluation of photogrammetric methods for dense 3D surface reconstruction in a metrological context

NASA Astrophysics Data System (ADS)

Toschi, I.; Capra, A.; De Luca, L.; Beraldin, J.-A.; Cournoyer, L.

2014-05-01

This paper discusses a methodology to evaluate the accuracy of recently developed image-based 3D modelling techniques. So far, the emergence of these novel methods has not been supported by the definition of an internationally recognized standard which is fundamental for user confidence and market growth. In order to provide an element of reflection and solution to the different communities involved in 3D imaging, a promising approach is presented in this paper for the assessment of both metric quality and limitations of an open-source suite of tools (Apero/MicMac), developed for the extraction of dense 3D point clouds from a set of unordered 2D images. The proposed procedural workflow is performed within a metrological context, through inter-comparisons with "reference" data acquired with two hemispherical laser scanners, one total station, and one laser tracker. The methodology is applied to two case studies, designed in order to analyse the software performances in dealing with both outdoor and environmentally controlled conditions, i.e. the main entrance of Cathédrale de la Major (Marseille, France) and a custom-made scene located at National Research Council of Canada 3D imaging Metrology Laboratory (Ottawa). Comparative data and accuracy evidence produced for both tests allow the study of some key factors affecting 3D model accuracy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

C. Priniski, T. Dodson, M. Duco, S. Raftopoulos, R. Ellis, and A. Brooks

In support of the National Compact Stellerator Experiment (NCSX), stellerator assembly activities continued this past year at the Princeton Plasma Physics Laboratory (PPPL) in partnership with the Oak Ridge National Laboratory (ORNL). The construction program saw the completion of the first two Half Field-Period Assemblies (HPA), each consisting of three modular coils. The full machine includes six such sub-assemblies. A single HPA consists of three of the NCSX modular coils wound and assembled at PPPL. These geometrically-complex threedimensional coils were wound using computer-aided metrology and CAD models to tolerances within +/- 0.5mm. The assembly of these coils required similar accuracymore » on a larger scale with the added complexity of more individual parts and fewer degrees of freedom for correction. Several new potential positioning issues developed for which measurement and control techniques were developed. To accomplish this, CAD coordinate-based computer metrology equipment and software similar to the solutions employed for winding the modular coils was used. Given the size of the assemblies, the primary tools were both interferometeraided and Absolute Distance Measurement (ADM)-only based laser trackers. In addition, portable Coordinate Measurement Machine (CMM) arms and some novel indirect measurement techniques were employed. This paper will detail both the use of CAD coordinate-based metrology technology and the techniques developed and employed for dimensional control of NSCX subassemblies. The results achieved and possible improvements to techniques will be discussed.« less

Ice flood velocity calculating approach based on single view metrology

NASA Astrophysics Data System (ADS)

Wu, X.; Xu, L.

2017-02-01

Yellow River is the river in which the ice flood occurs most frequently in China, hence, the Ice flood forecasting has great significance for the river flood prevention work. In various ice flood forecast models, the flow velocity is one of the most important parameters. In spite of the great significance of the flow velocity, its acquisition heavily relies on manual observation or deriving from empirical formula. In recent years, with the high development of video surveillance technology and wireless transmission network, the Yellow River Conservancy Commission set up the ice situation monitoring system, in which live videos can be transmitted to the monitoring center through 3G mobile networks. In this paper, an approach to get the ice velocity based on single view metrology and motion tracking technique using monitoring videos as input data is proposed. First of all, River way can be approximated as a plane. On this condition, we analyze the geometry relevance between the object side and the image side. Besides, we present the principle to measure length in object side from image. Secondly, we use LK optical flow which support pyramid data to track the ice in motion. Combining the result of camera calibration and single view metrology, we propose a flow to calculate the real velocity of ice flood. At last we realize a prototype system by programming and use it to test the reliability and rationality of the whole solution.

Optical characterisation of three reference Dobsons in the ATMOZ Project - verification of G. M. B. Dobson's original specifications

NASA Astrophysics Data System (ADS)

Köhler, Ulf; Nevas, Saulius; McConville, Glen; Evans, Robert; Smid, Marek; Stanek, Martin; Redondas, Alberto; Schönenborn, Fritz

2018-04-01

Three reference Dobsons (regional standard Dobsons No. 064, Germany and No. 074, Czech Republic as well as the world standard No. 083, USA) were optically characterized at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig in 2015 and at the Czech Metrology Institute (CMI) in Prague in 2016 within the EMRP ENV 059 project Traceability for atmospheric total column ozone. Slit functions and the related parameters of the instruments were measured and compared with G. M. B. Dobson's specifications in his handbook. All Dobsons show a predominantly good match of the slit functions and the peak (centroid) wavelengths with deviations between -0.11 and +0.12 nm and differences of the full width half maximum (FWHM) between 0.13 and 0.37 nm compared to the nominal values at the shorter wavelengths. Slightly larger deviations of the FWHMs from the nominal Dobson data, up to 1.22 nm, can be seen at the longer wavelengths, especially for the slit function of the long D-wavelength. However, differences between the effective absorption coefficients (EACs) for ozone derived using Dobson's nominal values of the optical parameters on one hand and these measured values on the other hand are not too large in the case of both old Bass-Paur (BP) and new IUP-ozone (Institut für Umweltphysik, University of Bremen) absorption cross sections. Their inclusion in the calculation of the total ozone column (TOC) leads to improvements of significantly less than ±1 % at the AD-wavelengths between -1 and -2 % at the CD-wavelengths pairs in the BP-scale. The effect on the TOC in the IUP-scale is somewhat larger at the AD-wavelengths, up to +1 % (D074), and smaller at the CD-wavelengths pair, from -0.44 to -1.5 %. Beside this positive effect gained from the data with higher metrological quality that is needed for trend analyses and satellite validation, it will be also possible to explain uncommon behaviours of field Dobsons during calibration services, especially when a newly developed transportable device TuPS (tuneable portable radiation source) from CMI proves its capability to provide similar results as the stationary setups in the laboratories of National Metrology Institutes. Then, the field Dobsons can be optically characterized as well during regular calibration campaigns. A corresponding publication will be prepared using the results of TuPS-based measurements of more than 10 Dobsons in field campaigns in 2017.

Purification of human adipose-derived stem cells from fat tissues using PLGA/silk screen hybrid membranes.

PubMed

Chen, Da-Chung; Chen, Li-Yu; Ling, Qing-Dong; Wu, Meng-Hsueh; Wang, Ching-Tang; Suresh Kumar, S; Chang, Yung; Munusamy, Murugan A; Alarfajj, Abdullah A; Wang, Han-Chow; Hsu, Shih-Tien; Higuchi, Akon

2014-05-01

The purification of human adipose-derived stem cells (hADSCs) from human adipose tissue cells (stromal vascular fraction) was investigated using membrane filtration through poly(lactide-co-glycolic acid)/silk screen hybrid membranes. Membrane filtration methods are attractive in regenerative medicine because they reduce the time required to purify hADSCs (i.e., less than 30 min) compared with conventional culture methods, which require 5-12 days. hADSCs expressing the mesenchymal stem cell markers CD44, CD73, and CD90 were concentrated in the permeation solution from the hybrid membranes. Expression of the surface markers CD44, CD73, and CD99 on the cells in the permeation solution from the hybrid membranes, which were obtained using 18 mL of feed solution containing 50 × 10⁴ cells, was statistically significantly higher than that of the primary adipose tissue cells, indicating that the hADSCs can be purified in the permeation solution by the membrane filtration method. Cells expressing the stem cell-associated marker CD34 could be successfully isolated in the permeation solution, whereas CD34⁺ cells could not be purified by the conventional culture method. The hADSCs in the permeation solution demonstrated a superior capacity for osteogenic differentiation based on their alkali phosphatase activity, their osterix gene expression, and the results of mineralization analysis by Alizarin Red S and von Kossa staining compared with the cells from the suspension of human adipose tissue. These results suggest that the hADSCs capable of osteogenic differentiation preferentially permeate through the hybrid membranes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Temperature-assisted photochemical construction of CdS-based ordered porous films with photocatalytic activities on solution surfaces.

PubMed

Huang, Zhenxun; Sun, Fengqiang; Zhang, Yu; Gu, Kaiyuan; Zou, Xueqiong; Huang, Yuying; Wu, Qingsong; Zhang, Zihe

2011-04-15

Taking a colloidal monolayer floating on the surface of a precursor solution as template, free-standing CdS/Cd composites and pure CdS (CdS-based) ordered porous films had been prepared by a temperature-assisted photochemical strategy. After irradiation with UV-light and heat treatment, the films formed hemi-spherical pores due to the preferable deposition of CdS and Cd onto the PS spheres during the photochemical and interfacial reactions. When the temperature increased from 15 to 60°C, the air/water interface gradually changed into a vapor/water interface on the surface of the solution, resulting in variations of the final compositions. The optical properties of the films were hence changed. Because of the free-standing characteristic, the ordered porous films were first transferred on surface of polluted solutions as photocatalysts, which was a new mode in application of photocatalysts. The photocatalytic activities of films showed regular variations with the compositions in photodegradation of Rhodamine B. This method provides a simple route for tuning the properties of porous films through control of its composition and a flexible application of films on any surface. Copyright © 2011 Elsevier Inc. All rights reserved.

CHAM: weak signals detection through a new multivariate algorithm for process control

NASA Astrophysics Data System (ADS)

Bergeret, François; Soual, Carole; Le Gratiet, B.

2016-10-01

Derivatives technologies based on core CMOS processes are significantly aggressive in term of design rules and process control requirements. Process control plan is a derived from Process Assumption (PA) calculations which result in a design rule based on known process variability capabilities, taking into account enough margin to be safe not only for yield but especially for reliability. Even though process assumptions are calculated with a 4 sigma known process capability margin, efficient and competitive designs are challenging the process especially for derivatives technologies in 40 and 28nm nodes. For wafer fab process control, PA are declined in monovariate (layer1 CD, layer2 CD, layer2 to layer1 overlay, layer3 CD etc….) control charts with appropriated specifications and control limits which all together are securing the silicon. This is so far working fine but such system is not really sensitive to weak signals coming from interactions of multiple key parameters (high layer2 CD combined with high layer3 CD as an example). CHAM is a software using an advanced statistical algorithm specifically designed to detect small signals, especially when there are many parameters to control and when the parameters can interact to create yield issues. In this presentation we will first present the CHAM algorithm, then the case-study on critical dimensions, with the results, and we will conclude on future work. This partnership between Ippon and STM is part of E450LMDAP, European project dedicated to metrology and lithography development for future technology nodes, especially 10nm.

Integrated approach to improving local CD uniformity in EUV patterning

NASA Astrophysics Data System (ADS)

Liang, Andrew; Hermans, Jan; Tran, Timothy; Viatkina, Katja; Liang, Chen-Wei; Ward, Brandon; Chuang, Steven; Yu, Jengyi; Harm, Greg; Vandereyken, Jelle; Rio, David; Kubis, Michael; Tan, Samantha; Dusa, Mircea; Singhal, Akhil; van Schravendijk, Bart; Dixit, Girish; Shamma, Nader

2017-03-01

Extreme ultraviolet (EUV) lithography is crucial to enabling technology scaling in pitch and critical dimension (CD). Currently, one of the key challenges of introducing EUV lithography to high volume manufacturing (HVM) is throughput, which requires high source power and high sensitivity chemically amplified photoresists. Important limiters of high sensitivity chemically amplified resists (CAR) are the effects of photon shot noise and resist blur on the number of photons received and of photoacids generated per feature, especially at the pitches required for 7 nm and 5 nm advanced technology nodes. These stochastic effects are reflected in via structures as hole-to-hole CD variation or local CD uniformity (LCDU). Here, we demonstrate a synergy of film stack deposition, EUV lithography, and plasma etch techniques to improve LCDU, which allows the use of high sensitivity resists required for the introduction of EUV HVM. Thus, to improve LCDU to a level required by 5 nm node and beyond, film stack deposition, EUV lithography, and plasma etch processes were combined and co-optimized to enhance LCDU reduction from synergies. Test wafers were created by depositing a pattern transfer stack on a substrate representative of a 5 nm node target layer. The pattern transfer stack consisted of an atomically smooth adhesion layer and two hardmasks and was deposited using the Lam VECTOR PECVD product family. These layers were designed to mitigate hole roughness, absorb out-of-band radiation, and provide additional outlets for etch to improve LCDU and control hole CD. These wafers were then exposed through an ASML NXE3350B EUV scanner using a variety of advanced positive tone EUV CAR. They were finally etched to the target substrate using Lam Flex dielectric etch and Kiyo conductor etch systems. Metrology methodologies to assess dimensional metrics as well as chip performance and defectivity were investigated to enable repeatable patterning process development. Illumination conditions in EUV lithography were optimized to improve normalized image log slope (NILS), which is expected to reduce shot noise related effects. It can be seen that the EUV imaging contrast improvement can further reduce post-develop LCDU from 4.1 nm to 3.9 nm and from 2.8 nm to 2.6 nm. In parallel, etch processes were developed to further reduce LCDU, to control CD, and to transfer these improvements into the final target substrate. We also demonstrate that increasing post-develop CD through dose adjustment can enhance the LCDU reduction from etch. Similar trends were also observed in different pitches down to 40 nm. The solutions demonstrated here are critical to the introduction of EUV lithography in high volume manufacturing. It can be seen that through a synergistic deposition, lithography, and etch optimization, LCDU at a 40 nm pitch can be improved to 1.6 nm (3-sigma) in a target oxide layer and to 1.4 nm (3-sigma) at the photoresist layer.

SOLEIL shining on the solution-state structure of biomacromolecules by synchrotron X-ray footprinting at the Metrology beamline.

PubMed

Baud, A; Aymé, L; Gonnet, F; Salard, I; Gohon, Y; Jolivet, P; Brodolin, K; Da Silva, P; Giuliani, A; Sclavi, B; Chardot, T; Mercère, P; Roblin, P; Daniel, R

2017-05-01

Synchrotron X-ray footprinting complements the techniques commonly used to define the structure of molecules such as crystallography, small-angle X-ray scattering and nuclear magnetic resonance. It is remarkably useful in probing the structure and interactions of proteins with lipids, nucleic acids or with other proteins in solution, often better reflecting the in vivo state dynamics. To date, most X-ray footprinting studies have been carried out at the National Synchrotron Light Source, USA, and at the European Synchrotron Radiation Facility in Grenoble, France. This work presents X-ray footprinting of biomolecules performed for the first time at the X-ray Metrology beamline at the SOLEIL synchrotron radiation source. The installation at this beamline of a stopped-flow apparatus for sample delivery, an irradiation capillary and an automatic sample collector enabled the X-ray footprinting study of the structure of the soluble protein factor H (FH) from the human complement system as well as of the lipid-associated hydrophobic protein S3 oleosin from plant seed. Mass spectrometry analysis showed that the structural integrity of both proteins was not affected by the short exposition to the oxygen radicals produced during the irradiation. Irradiated molecules were subsequently analysed using high-resolution mass spectrometry to identify and locate oxidized amino acids. Moreover, the analyses of FH in its free state and in complex with complement C3b protein have allowed us to create a map of reactive solvent-exposed residues on the surface of FH and to observe the changes in oxidation of FH residues upon C3b binding. Studies of the solvent accessibility of the S3 oleosin show that X-ray footprinting offers also a unique approach to studying the structure of proteins embedded within membranes or lipid bodies. All the biomolecular applications reported herein demonstrate that the Metrology beamline at SOLEIL can be successfully used for synchrotron X-ray footprinting of biomolecules.

Adsorption of cadmium by biochar produced from pyrolysis of corn stalk in aqueous solution.

PubMed

Ma, Fengfeng; Zhao, Baowei; Diao, Jingru

2016-09-01

The purpose of this work is to investigate adsorption characteristic of corn stalk (CS) biochar for removal of cadmium ions (Cd 2+ ) from aqueous solution. Batch adsorption experiments were carried out to evaluate the effects of pH value of solution, adsorbent particle size, adsorbent dosage, and ionic strength of solution on the adsorption of Cd 2+ onto biochar that was pyrolytically produced from CS at 300 °C. The results showed that the initial pH value of solution played an important role in adsorption. The adsorptive amount of Cd 2+ onto the biochar decreased with increasing the adsorbent dosage, adsorbent particle size, and ionic strength, while it increased with increasing the initial pH value of solution and temperature. Cd 2+ was removed efficiently and quickly from aqueous solutions by the biochar with a maximum capacity of 33.94 mg/g. The adsorption process was well described by the pseudo-second-order kinetic model with the correlation coefficients greater than 0.986. The adsorption isotherm could be well fitted by the Langmuir model. The thermodynamic studies showed that the adsorption of Cd 2+ onto the biochar was a spontaneous and exothermic process. The results indicate that CS biochar can be considered as an efficient adsorbent.

Effective EUVL mask cleaning technology solutions for mask manufacturing and in-fab mask maintenance

NASA Astrophysics Data System (ADS)

Dietze, Uwe; Dress, Peter; Waehler, Tobias; Singh, Sherjang; Jonckheere, Rik; Baudemprez, Bart

2011-03-01

Extreme Ultraviolet Lithography (EUVL) is considered the leading lithography technology choice for semiconductor devices at 16nm HP node and beyond. However, before EUV Lithography can enter into High Volume Manufacturing (HVM) of advanced semiconductor devices, the ability to guarantee mask integrity at point-of-exposure must be established. Highly efficient, damage free mask cleaning plays a critical role during the mask manufacturing cycle and throughout the life of the mask, where the absence of a pellicle to protect the EUV mask increases the risk of contamination during storage, handling and use. In this paper, we will present effective EUVL mask cleaning technology solutions for mask manufacturing and in-fab mask maintenance, which employs an intelligent, holistic approach to maximize Mean Time Between Cleans (MBTC) and extend the useful life span of the reticle. The data presented will demonstrate the protection of the capping and absorber layers, preservation of pattern integrity as well as optical and mechanical properties to avoid unpredictable CD-linewidth and overlay shifts. Experiments were performed on EUV blanks and pattern masks using various process conditions. Conditions showing high particle removal efficiency (PRE) and minimum surface layer impact were then selected for durability studies. Surface layer impact was evaluated over multiple cleaning cycles by means of UV reflectivity metrology XPS analysis and wafer prints. Experimental results were compared to computational models. Mask life time predictions where made using the same computational models. The paper will provide a generic overview of the cleaning sequence which yielded best results, but will also provide recommendations for an efficient in-fab mask maintenance scheme, addressing handling, storage, cleaning and inspection.

Metrology in physics, chemistry, and biology: differing perceptions.

PubMed

Iyengar, Venkatesh

2007-04-01

The association of physics and chemistry with metrology (the science of measurements) is well documented. For practical purposes, basic metrological measurements in physics are governed by two components, namely, the measure (i.e., the unit of measurement) and the measurand (i.e., the entity measured), which fully account for the integrity of a measurement process. In simple words, in the case of measuring the length of a room (the measurand), the SI unit meter (the measure) provides a direct answer sustained by metrological concepts. Metrology in chemistry, as observed through physical chemistry (measures used to express molar relationships, volume, pressure, temperature, surface tension, among others) follows the same principles of metrology as in physics. The same basis percolates to classical analytical chemistry (gravimetry for preparing high-purity standards, related definitive analytical techniques, among others). However, certain transition takes place in extending the metrological principles to chemical measurements in complex chemical matrices (e.g., food samples), as it adds a third component, namely, indirect measurements (e.g., AAS determination of Zn in foods). This is a practice frequently used in field assays, and calls for additional steps to account for traceability of such chemical measurements for safeguarding reliability concerns. Hence, the assessment that chemical metrology is still evolving.

MSFC Optical Metrology: A National Resource

NASA Technical Reports Server (NTRS)

Burdine, Robert

1998-01-01

A national need exists for Large Diameter Optical Metrology Services. These services include the manufacture, testing, and assurance of precision and control necessary to assure the success of large optical projects. "Best Practices" are often relied on for manufacture and quality controls while optical projects are increasingly more demanding and complex. Marshall Space Flight Center (MSFC) has acquired unique optical measurement, testing and metrology capabilities through active participation in a wide variety of NASA optical programs. An overview of existing optical facilities and metrology capabilities is given with emphasis on use by other optical projects. Cost avoidance and project success is stressed through use of existing MSFC facilities and capabilities for measurement and metrology controls. Current issues in large diameter optical metrology are briefly reviewed. The need for a consistent and long duration Large Diameter Optical Metrology Service Group is presented with emphasis on the establishment of a National Large Diameter Optical Standards Laboratory. Proposals are made to develop MSFC optical standards and metrology capabilities as the primary national standards resource, providing access to MSFC Optical Core Competencies for manufacturers and researchers. Plans are presented for the development of a national lending library of precision optical standards with emphasis on cost avoidance while improving measurement assurance.

Retention properties of novel beta-CD bonded stationary phases in reversed-phase HPLC mode.

PubMed

Zhao, Yanyan; Guo, Zhimou; Zhang, Yongping; Xue, Xingya; Xu, Qing; Li, Xiuling; Liang, Xinmiao; Zhang, Yukui

2009-05-15

With the given special structures, the CD bonded stationary phases are expected to have complementary retention properties with conventional C18 stationary phase, which will be helpful to enhance the polar selectivity in RP mode separation. In this work, two beta-cyclodextrin (beta-CD) bonded stationary phases for reversed-phase HPLC, including 1, 12-dodecyldiol linked beta-CD stationary phase (CD1) and olio (ethylene glycol) (OEG) linked beta-CD stationary phase (CD2), have been synthesized via click chemistry. The resulting materials were characterized with FT-IR and elemental analysis, which proved the successful immobilization of ligands. The similarities and differences in retention characteristics between the CD and C18 stationary phases have been elucidated by using comparative linear solvation energy relationships (LSERs). The force related to solute McGowan volume has no significant difference, while the hydrogen bonding and dipolar interactions between solutes and CD stationary phases are stronger than between solutes and C18, which is attributed to the special structures (CD and triazole groups) of CD stationary phases. Chemical origins are interpreted by comparison between CD1 and CD2. Similar dispersive interactions of CD1 and CD2 are attributed to their similar length of spacer arms. CD2 which contains OEG spacer arm has relative weaker HBD acidity but stronger HBA basicity. CD stationary phases display no serious different methylene selectivity and higher polar selectivity than in the case of C18. Higher acid selectivity and lower basic selectivity are observed on CD2 than on CD1. Distinctive retention properties and good complementary separation selectivity to C18 make the novel CD bonded stationary phases available for more application in RPLC.

Long-Baseline Comparisons of the Brazilian National Time Scale to UTC (NIST) Using Near Real-Time and Postprocessed Solutions

DTIC Science & Technology

2007-11-01

long baseline of ~8600 km. The comparisons were made with measurement systems developed for the Sistema Interamericano de Metrologia (SIM) comparison...measurements are compared and summarized. I. INTRODUCTION The Sistema Interamericano de Metrologia (SIM) is a regional metrology organization...Brazil. The two time scales are separated by a long baseline of ~8600 km. The comparisons were made with measurement systems developed for the Sistema

Methodological possibilities for the solution of new tasks for “Thermophysics of Power Units” Department of SPbPU

NASA Astrophysics Data System (ADS)

Sapozhnikov, S. Z.; Mityakov, V. Yu; Mityakov, A. V.; Gusakov, A. A.

2017-11-01

“Thermophysics of Power Units” Department is based on pre-existed “Thermodynamics and Heat Transfer” and “Reactors and Boilers” Departments. The main goal of the new department (in addition to training students in basic courses of Thermodynamics, Heat and Mass Transfer, Fluid Mechanics, Metrology and Thermal Measurement) has become a new master’s profile “Thermal Engineering, Energy Audit and Energy Service”. It required radical restructuring of the whole educational process, and in the first place - its material resources and equipment. Over the last two years “Heat and Mass Transfer” lab and “Wind tunnel” lab are upgraded, and “Metrology and Thermophysical Measurement” lab is newly created. Tutorials of new generation are changing significantly the structure of our main courses. The members of our scientific group (2 - 6 year students) actively engaged in the work process. Now we hope to see the best of them among our future postgraduates.

Study of μDBO overlay target size reduction for application broadening

NASA Astrophysics Data System (ADS)

Calado, Victor; Dépré, Jérôme; Massacrier, Clément; Tarabrin, Sergey; van Haren, Richard; Dettoni, Florent; Bouyssou, Régis; Dezauzier, Christophe

2018-03-01

With these proceedings we present μ-diffraction-based overlay (μDBO) targets that are well below the currently supported minimum size of 10×10 μm2 . We have been capable of measuring overlay targets as small as 4×4 μm2 with our latest generation YieldStar system. Furthermore we find an excellent precision (TMU < 0.33 nm for 6 × 6 μm2 ) without any compromise on throughput (MAM time < 60 ms). At last a study that compares four generations of YieldStar systems show clearly that the latest generation YieldStar systems is much better capable of reading small overlay targets such that the performance of a 16 × 16 μm2 on an early generation YieldStar 2nd-gen is comparable to that of a 8 × 8 μm2 on the latest YieldStar 5th-gen. This work enables a smaller metrology footprint, more placement flexibility and in-die overlay metrology solutions.

Standardisation of the (129)I, (151)Sm and (166m)Ho activity concentration using the CIEMAT/NIST efficiency tracing method.

PubMed

Altzitzoglou, Timotheos; Rožkov, Andrej

2016-03-01

The (129)I, (151)Sm and (166m)Ho standardisations using the CIEMAT/NIST efficiency tracing method, that have been carried out in the frame of the European Metrology Research Program project "Metrology for Radioactive Waste Management" are described. The radionuclide beta counting efficiencies were calculated using two computer codes CN2005 and MICELLE2. The sensitivity analysis of the code input parameters (ionization quenching factor, beta shape factor) on the calculated efficiencies was performed, and the results are discussed. The combined relative standard uncertainty of the standardisations of the (129)I, (151)Sm and (166m)Ho solutions were 0.4%, 0.5% and 0.4%, respectively. The stated precision obtained using the CIEMAT/NIST method is better than that previously reported in the literature obtained by the TDCR ((129)I), the 4πγ-NaI ((166m)Ho) counting or the CIEMAT/NIST method ((151)Sm). Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Reducing the overlay metrology sensitivity to perturbations of the measurement stack

NASA Astrophysics Data System (ADS)

Zhou, Yue; Park, DeNeil; Gutjahr, Karsten; Gottipati, Abhishek; Vuong, Tam; Bae, Sung Yong; Stokes, Nicholas; Jiang, Aiqin; Hsu, Po Ya; O'Mahony, Mark; Donini, Andrea; Visser, Bart; de Ruiter, Chris; Grzela, Grzegorz; van der Laan, Hans; Jak, Martin; Izikson, Pavel; Morgan, Stephen

2017-03-01

Overlay metrology setup today faces a continuously changing landscape of process steps. During Diffraction Based Overlay (DBO) metrology setup, many different metrology target designs are evaluated in order to cover the full process window. The standard method for overlay metrology setup consists of single-wafer optimization in which the performance of all available metrology targets is evaluated. Without the availability of external reference data or multiwafer measurements it is hard to predict the metrology accuracy and robustness against process variations which naturally occur from wafer-to-wafer and lot-to-lot. In this paper, the capabilities of the Holistic Metrology Qualification (HMQ) setup flow are outlined, in particular with respect to overlay metrology accuracy and process robustness. The significance of robustness and its impact on overlay measurements is discussed using multiple examples. Measurement differences caused by slight stack variations across the target area, called grating imbalance, are shown to cause significant errors in the overlay calculation in case the recipe and target have not been selected properly. To this point, an overlay sensitivity check on perturbations of the measurement stack is presented for improvement of the overlay metrology setup flow. An extensive analysis on Key Performance Indicators (KPIs) from HMQ recipe optimization is performed on µDBO measurements of product wafers. The key parameters describing the sensitivity to perturbations of the measurement stack are based on an intra-target analysis. Using advanced image analysis, which is only possible for image plane detection of μDBO instead of pupil plane detection of DBO, the process robustness performance of a recipe can be determined. Intra-target analysis can be applied for a wide range of applications, independent of layers and devices.

Continuous Microreactor-Assisted Solution Deposition for Scalable Production of CdS Films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramprasad, Sudhir; Su, Yu-Wei; Chang, Chih-Hung

2013-06-13

Solution deposition offers an attractive, low temperature option in the cost effective production of thin film solar cells. Continuous microreactor-assisted solution deposition (MASD) was used to produce nanocrystalline cadmium sulfide (CdS) films on fluorine doped tin oxide (FTO) coated glass substrates with excellent uniformity. We report a novel liquid coating technique using a ceramic rod to efficiently and uniformly apply reactive solution to large substrates (152 mm × 152 mm). This technique represents an inexpensive approach to utilize the MASD on the substrate for uniform growth of CdS films. Nano-crystalline CdS films have been produced from liquid phase at ~90°C,more » with average thicknesses of 70 nm to 230 nm and with a 5 to 12% thickness variation. The CdS films produced were characterized by UV-Vis spectroscopy, transmission electron microscopy, and X-Ray diffraction to demonstrate their suitability to thin-film solar technology.« less

Overlay accuracy fundamentals

NASA Astrophysics Data System (ADS)

Kandel, Daniel; Levinski, Vladimir; Sapiens, Noam; Cohen, Guy; Amit, Eran; Klein, Dana; Vakshtein, Irina

2012-03-01

Currently, the performance of overlay metrology is evaluated mainly based on random error contributions such as precision and TIS variability. With the expected shrinkage of the overlay metrology budget to < 0.5nm, it becomes crucial to include also systematic error contributions which affect the accuracy of the metrology. Here we discuss fundamental aspects of overlay accuracy and a methodology to improve accuracy significantly. We identify overlay mark imperfections and their interaction with the metrology technology, as the main source of overlay inaccuracy. The most important type of mark imperfection is mark asymmetry. Overlay mark asymmetry leads to a geometrical ambiguity in the definition of overlay, which can be ~1nm or less. It is shown theoretically and in simulations that the metrology may enhance the effect of overlay mark asymmetry significantly and lead to metrology inaccuracy ~10nm, much larger than the geometrical ambiguity. The analysis is carried out for two different overlay metrology technologies: Imaging overlay and DBO (1st order diffraction based overlay). It is demonstrated that the sensitivity of DBO to overlay mark asymmetry is larger than the sensitivity of imaging overlay. Finally, we show that a recently developed measurement quality metric serves as a valuable tool for improving overlay metrology accuracy. Simulation results demonstrate that the accuracy of imaging overlay can be improved significantly by recipe setup optimized using the quality metric. We conclude that imaging overlay metrology, complemented by appropriate use of measurement quality metric, results in optimal overlay accuracy.

Fluorescein dye improves microscopic evaluation and counting of demodex in blepharitis with cylindrical dandruff.

PubMed

Kheirkhah, Ahmad; Blanco, Gabriela; Casas, Victoria; Tseng, Scheffer C G

2007-07-01

To show whether fluorescein dye helps detect and count Demodex embedded in cylindrical dandruff (CD) of epilated eyelashes from patients with blepharitis. Two eyelashes with CD were removed from each lid of 10 consecutive patients with blepharitis and subjected to microscopic examination with and without fluorescein solution to detect and count Demodex mites. Of 80 eyelashes examined, 36 (45%) lashes retained their CD after removal. Before addition of the fluorescein solution, the mean total Demodex count per patient was 14.9 +/- 10 and the mean Demodex count per lash was 3.1 +/- 2.5 and 0.8 +/- 0.7 in epilated eyelashes with and without retained CD, respectively (P < 0.0001). After addition of the fluorescein solution, opaque and compact CD instantly expanded to reveal embedded mites in a yellowish and semitransparent background. As a result, the mean total Demodex count per patient was significantly increased to 20.2 +/- 13.8 (P = 0.003), and the mean count per lash was significantly increased to 4.4 +/- 2.8 and 1 +/- 0.8 in eyelashes with and without retained CD (P < 0.0001 and P = 0.007), respectively. This new method yielded more mites in 8 of 10 patients and allowed mites to be detected in 3 lashes with retained CD and 1 lash without retained CD that had an initial count of zero. Addition of fluorescein solution after mounting further increases the proficiency of detecting and counting mites embedded in CD of epilated eyelashes.

Photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite films in an aerated 0.5 M NaCl solution

NASA Astrophysics Data System (ADS)

Boonserm, Aleena; Kruehong, Chaiyaput; Seithtanabutara, Varinrumpai; Artnaseaw, Apichart; Kwakhong, Panomkorn

2017-10-01

This research aimed to investigate the photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite films using electrochemical measurements in an aerated 0.5 M NaCl solution under white light illumination. The CdS/TiO2 nanocomposite films were prepared by chemical bath deposition technique in a solution of cadmium and sulfide ions. The high resolution images of CdS/TiO2 nanocomposite films were provided by field emission scanning electron microscope. Theirs chemical identification and quantitative compositional information, crystallinity and actual chemical compounds formed were determined by energy dispersive spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The results indicated that the photoelectrochemical activity of the films depended strongly on CdS content. From the preparation of CdS/TiO2 nanocomposite films by 5, 10 and 15 dipping cycles in the chemical solutions, the best photoelectrochemical response was revealed by the 10 dipping cycles-prepared film. Galvanic couple testing demonstrated that the photoelectrochemical response of the film decreased continuously compared to that of anodized nanoporous TiO2 substrate which described by photocorrosion of CdS nanoparticles. In addition, chloride-ion attack also induced pitting corrosion leading to fluctuation and deterioration of photoelectrochemical response. CdO2 and Cd(OH)2 depositions were found as the main photocorrosion products on collapsed nanostructured-surface. The relevance between photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite film was discussed in detail.

Pattern fidelity in nanoimprinted films using CD-SAXS

NASA Astrophysics Data System (ADS)

Jones, Ronald L.; Soles, Christopher L.; Lin, Eric K.; Hu, Walter; Reano, Ronald M.; Pang, Stella W.; Weigand, Steven J.; Keane, Denis T.; Quintana, John P.

2005-05-01

The primary measure of process quality in nanoimprint lithography (NIL) is the fidelity of pattern transfer, comparing the dimensions of the imprinted pattern to those of the mold. As a potential next generation lithography, NIL is capable of true nanofabrication, producing patterns of sub-10 nm dimensions. Routine production of nanoscale patterns will require new metrologies capable of non-destructive dimensional measurements of both the mold and the pattern with sub-nm precision. In this article, a rapid, non-destructive technique termed Critical Dimension Small Angle X-ray Scattering (CD-SAXS) is used to measure the cross sectional shape of both a pattern master, or mold, and the resulting imprinted films. CD-SAXS data are used to extract periodicity as well as pattern height, width, and sidewall angles. Films of varying materials are molded by thermal embossed NIL at temperatures both near and far from the bulk glass transition (TG). The polymer systems include a photoresist, representing a mixture of a polymer and small molecular components, and two pure homopolymers. Molding at low temperatures (T-TG < 40°C) produces small aspect ratio patterns that maintain periodicity to within a single nanometer, but feature large sidewall angles. While the pattern height does not reach that of the mold until very large imprinting temperatures (T-TG ~ 70°C), the pattern width of the mold is accurately transferred for T-TG > 30°C. In addition to obtaining basic dimensions, CD-SAXS data are used to assess the origin of loss in pattern fidelity.

Report of the CCQM-K124: trace elements and chromium speciation in drinking water—part A: trace elements in drinking water, part B: chromium speciation in drinking water

NASA Astrophysics Data System (ADS)

Kuroiwa, T.; Fung, W. H.; Zhu, Y.; Inagaki, K.; Sin, D. W. M.; Chu, H. S.; Saxby, D.; Merrick, J.; White, I.; Araujo, T.; Almeida, M. D.; Rodrigues, J.; Yang, L.; Pihillagawa, I. G.; Mester, Z.; Riquelme, S. S.; Pérez, L.; Barriga, R.; Núñez, C.; Chao, J.; Wang, J.; Wang, Q.; Shi, N.; Lu, H.; Song, P.; Nüykki, T.; Aho, T. Sara; Labarraque, G.; Oster, C.; Rienitz, O.; Jührling, R.; Pape, C.; Lampi, E.; Kakoulides, E.; Ketrin, R.; Mardika, E.; Komalasari, I.; Okumu, T. O.; Kang'iri, J. N.; Yim, Y. H.; Heo, S. W.; Lee, K. S.; Suh, J. K.; Lim, Y.; Manzano, J. V. L.; Uribe, C.; Carrasco, E.; Tayag, E. D.; Dablio, A. R. C.; Encarnacion, E. K. P.; Damian, R. L.; Konopelko, L.; Krylov, A.; Vadim, S.; Shin, R.; Peng, S. L.; Juan, W.; Chang, X.; Dewi, F.; Horvat, M.; Zuliani, T.; Taebunpakul, S.; Yafa, C.; Kaewkhomdee, N.; Thiengmanee, U.; Klich, H.; Can, S. Z.; Ari, B.; Cankur, O.; Goenaga Infante, H.; Ferreira, E.; Pérez, R.; E Long, S.; Kassim, B. L.; E Murphy, K.; Molloy, J. L.; Butler, T. A.

2017-01-01

CCQM-K124 was organized by the Inorganic Analysis Working Group (IAWG) of CCQM to assess and document the capabilities of the national metrology institutes (NMIs) or the designated institutes (DIs) to measure the mass fractions of trace elements (As, B, Cd, Ca, Cr, Hg and Mo) and hexavalent chromium (Cr(VI)) in drinking water. The National Metrology Institute of Japan (NMIJ) and the Government Laboratory, Hong Kong SAR (GLHK) acted as the coordinating laboratories. This comparison is divided into two parts. Part A was organized by the NMIJ and the trace elements were the analytes, and Part B was organised by the GLHK and Cr(VI) was the analyte. In Part A, results were submitted by 14 NMIs and nine DIs. The participants used different measurement methods, though most of them used direct measurement using inductively coupled plasma-optical emission spectrometry (ICP-OES), inductively coupled plasma-mass spectrometry (ICP-MS), and isotope dilution technique with ICP-MS. The results of As, B, Cd, Ca and Cr show good agreement with the exception of some outliers. Concerning Hg, instability was observed when the sample was stored in the light. And some participants observed instability of Mo. Therefore, it was agreed to abandon the Hg and Mo analysis as this sample was not satisfactory for KC. In Part B, results were submitted by six NMIs and one DI. The methods applied were direct measurement using 1,5-diphenylcarbazide (DPC) derivatisation UV-visible spectrophotometry, standard addition using ion chromatography-UV-visible spectrophotometry or HPLC—inductively coupled plasma-mass spectrometry (ICP-MS) and isotope dilution technique with ion chromatography—ICP-MS. The results of all participants show good agreement. Accounting for relative expanded uncertainty, comparability of measurement results for each of As, B, Cd, Ca, Cr and Cr(VI) was successfully demonstrated by the participating NMIs or DIs. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Metrological AFMs and its application for versatile nano-dimensional metrology tasks

NASA Astrophysics Data System (ADS)

Dai, Gaoliang; Dziomba, T.; Pohlenz, F.; Danzebrink, H.-U.; Koenders, L.

2010-08-01

Traceable calibrations of various micro and nano measurement devices are crucial tasks for ensuring reliable measurements for micro and nanotechnology. Today metrological AFM are widely used for traceable calibrations of nano dimensional standards. In this paper, we introduced the developments of metrological force microscopes at PTB. Of the three metrological AFMs described here, one is capable of measuring in a volume of 25 mm x 25 mm x 5 mm. All instruments feature interferometers and the three-dimensional position measurements are thus directly traceable to the metre definition. Some calibration examples on, for instance, flatness standards, step height standards, one and two dimensional gratings are demonstrated.

Metrological Support in Technosphere Safety

NASA Astrophysics Data System (ADS)

Akhobadze, G. N.

2017-11-01

The principle of metrological support in technosphere safety is considered. It is based on the practical metrology. The theoretical aspects of accuracy and errors of the measuring instruments intended for diagnostics and control of the technosphere under the influence of factors harmful to human beings are presented. The necessity to choose measuring devices with high metrological characteristics according to the accuracy class and contact of sensitive elements with a medium under control is shown. The types of additional errors in measuring instruments that arise when they are affected by environmental influences are described. A specific example of the analyzers application to control industrial emissions and measure the oil and particulate matter in wastewater is shown; it allows assessing advantages and disadvantages of analyzers. Besides, the recommendations regarding the missing metrological characteristics of the instruments in use are provided. The technosphere continuous monitoring taking into account the metrological principles is expected to efficiently forecast the technosphere development and make appropriate decisions.

PREFACE: 13th International Conference on Metrology and Properties of Engineering Surfaces

NASA Astrophysics Data System (ADS)

Leach, Richard

2011-08-01

The 13th International Conference on Metrology and Properties of Engineering Surfaces focused on the progress in surface metrology, surface characterisation instrumentation and properties of engineering surfaces. The conference provided an international forum for academics, industrialists and engineers from different disciplines to meet and exchange their ideas, results and latest research. The conference was held at Twickenham Stadium, situated approximately six miles from Heathrow Airport and approximately three miles from the National Physical Laboratory (NPL). This was the thirteenth in the very successful series of conferences, which have firmly established surface topography as a new and exciting interdisciplinary field of scientific and technological studies. Scientific Themes: Surface, Micro and Nano Metrology Measurement and Instrumentation Metrology for MST Devices Freeform Surface Measurement and Characterisation Uncertainty, Traceability and Calibration AFM/SPM Metrology Tribology and Wear Phenomena Functional Applications Stylus and Optical Instruments

Entanglement-enhanced quantum metrology in a noisy environment

NASA Astrophysics Data System (ADS)

Wang, Kunkun; Wang, Xiaoping; Zhan, Xiang; Bian, Zhihao; Li, Jian; Sanders, Barry C.; Xue, Peng

2018-04-01

Quantum metrology overcomes standard precision limits and plays a central role in science and technology. Practically, it is vulnerable to imperfections such as decoherence. Here we demonstrate quantum metrology for noisy channels such that entanglement with ancillary qubits enhances the quantum Fisher information for phase estimation but not otherwise. Our photonic experiment covers a range of noise for various types of channels, including for two randomly alternating channels such that assisted entanglement fails for each noisy channel individually. We simulate noisy channels by implementing space-multiplexed dual interferometers with quantum photonic inputs. We demonstrate the advantage of entanglement-assisted protocols in a phase estimation experiment run with either a single-probe or multiprobe approach. These results establish that entanglement with ancillae is a valuable approach for delivering quantum-enhanced metrology. Our approach to entanglement-assisted quantum metrology via a simple linear-optical interferometric network with easy-to-prepare photonic inputs provides a path towards practical quantum metrology.

Fast and accurate: high-speed metrological large-range AFM for surface and nanometrology

NASA Astrophysics Data System (ADS)

Dai, Gaoliang; Koenders, Ludger; Fluegge, Jens; Hemmleb, Matthias

2018-05-01

Low measurement speed remains a major shortcoming of the scanning probe microscopic technique. It not only leads to a low measurement throughput, but a significant measurement drift over the long measurement time needed (up to hours or even days). To overcome this challenge, PTB, the national metrology institute of Germany, has developed a high-speed metrological large-range atomic force microscope (HS Met. LR-AFM) capable of measuring speeds up to 1 mm s‑1. This paper has introduced the design concept in detail. After modelling scanning probe microscopic measurements, our results suggest that the signal spectrum of the surface to be measured is the spatial spectrum of the surface scaled by the scanning speed. The higher the scanning speed , the broader the spectrum to be measured. To realise an accurate HS Met. LR-AFM, our solution is to combine different stages/sensors synchronously in measurements, which provide a much larger spectrum area for high-speed measurement capability. Two application examples have been demonstrated. The first is a new concept called reference areal surface metrology. Using the developed HS Met. LR-AFM, surfaces are measured accurately and traceably at a speed of 500 µm s‑1 and the results are applied as a reference 3D data map of the surfaces. By correlating the reference 3D data sets and 3D data sets of tools under calibration, which are measured at the same surface, it has the potential to comprehensively characterise the tools, for instance, the spectrum properties of the tools. The investigation results of two commercial confocal microscopes are demonstrated, indicating very promising results. The second example is the calibration of a kind of 3D nano standard, which has spatially distributed landmarks, i.e. special unique features defined by 3D-coordinates. Experimental investigations confirmed that the calibration accuracy is maintained at a measurement speed of 100 µm s‑1, which improves the calibration efficiency by a factor of 10.

Recycling of CdTe photovoltaic waste

DOEpatents

Goozner, Robert E.; Long, Mark O.; Drinkard, Jr., William F.

1999-04-27

A method for extracting and reclaiming metals from scrap CdTe photovoltaic cells and manufacturing waste by leaching the metals in dilute nitric acid, leaching the waste with a leaching solution comprising nitric acid and water, skimming any plastic material from the top of the leaching solution, separating the glass substrate from the liquid leachate, adding a calcium containing base to the leachate to precipitate Cd and Te, separating the precipitated Cd and Te from the leachate, and recovering the calcium-containing base.

Recycling of CdTe photovoltaic waste

DOEpatents

Goozner, R.E.; Long, M.O.; Drinkard, W.F. Jr.

1999-04-27

A method for extracting and reclaiming metals from scrap CdTe photovoltaic cells and manufacturing waste by leaching the metals in dilute nitric acid, leaching the waste with a leaching solution comprising nitric acid and water, skimming any plastic material from the top of the leaching solution, separating the glass substrate from the liquid leachate, adding a calcium containing base to the leachate to precipitate Cd and Te, separating the precipitated Cd and Te from the leachate, and recovering the calcium-containing base. 3 figs.

A Roadmap for Thermal Metrology

NASA Astrophysics Data System (ADS)

Bojkovski, J.; Fischer, J.; Machin, G.; Pavese, F.; Peruzzi, A.; Renaot, E.; Tegeler, E.

2009-02-01

A provisional roadmap for thermal metrology was developed in Spring 2006 as part of the EUROMET iMERA activity toward increasing impact from national investment in European metrology R&D. This consisted of two parts: one addressing the influence of thermal metrology on society, industry, and science, and the other specifying the requirements of enabling thermal metrology to serve future needs. The roadmap represents the shared vision of the EUROMET TC Therm committee as to how thermal metrology should develop to meet future requirements over the next 15 years. It is important to stress that these documents are a first attempt to roadmap the whole of thermal metrology and will certainly need regular review and revision to remain relevant and useful to the community they seek to serve. The first part of the roadmap, “Thermal metrology for society, industry, and science,” identifies the main social and economic triggers driving developments in thermal metrology—notably citizen safety and security, new production technologies, environment and global climate change, energy, and health. Stemming from these triggers, key targets are identified that require improved thermal measurements. The second part of the roadmap, “Enabling thermal metrology to serve future needs” identifies another set of triggers, like global trade and interoperability, future needs in transport, and the earth radiation budget. Stemming from these triggers, key targets are identified, such as improved realizations and dissemination of the SI unit the kelvin, anchoring the kelvin to the Boltzmann constant, k B, and calculating thermal properties from first principles. To facilitate these outcomes, the roadmap identifies the technical advances required in thermal measurement standards.

Metrology needs for the semiconductor industry over the next decade

NASA Astrophysics Data System (ADS)

Melliar-Smith, Mark; Diebold, Alain C.

1998-11-01

Metrology will continue to be a key enabler for the development and manufacture of future generations of integrated circuits. During 1997, the Semiconductor Industry Association renewed the National Technology Roadmap for Semiconductors (NTRS) through the 50 nm technology generation and for the first time included a Metrology Roadmap (1). Meeting the needs described in the Metrology Roadmap will be both a technological and financial challenge. In an ideal world, metrology capability would be available at the start of process and tool development, and silicon suppliers would have 450 mm wafer capable metrology tools in time for development of that wafer size. Unfortunately, a majority of the metrology suppliers are small companies that typically can't afford the additional two to three year wait for return on R&D investment. Therefore, the success of the semiconductor industry demands that we expand cooperation between NIST, SEMATECH, the National Labs, SRC, and the entire community. In this paper, we will discuss several critical metrology topics including the role of sensor-based process control, in-line microscopy, focused measurements for transistor and interconnect fabrication, and development needs. Improvements in in-line microscopy must extend existing critical dimension measurements up to 100 nm generations and new methods may be required for sub 100 nm generations. Through development, existing metrology dielectric thickness and dopant dose and junction methods can be extended to 100 nm, but new and possibly in-situ methods are needed beyond 100 nm. Interconnect process control will undergo change before 100 nm due to the introduction of copper metallization, low dielectric constant interlevel dielectrics, and Damascene process flows.

High order field-to-field corrections for imaging and overlay to achieve sub 20-nm lithography requirements

NASA Astrophysics Data System (ADS)

Mulkens, Jan; Kubis, Michael; Hinnen, Paul; de Graaf, Roelof; van der Laan, Hans; Padiy, Alexander; Menchtchikov, Boris

2013-04-01

Immersion lithography is being extended to the 20-nm and 14-nm node and the lithography performance requirements need to be tightened further to enable this shrink. In this paper we present an integral method to enable high-order fieldto- field corrections for both imaging and overlay, and we show that this method improves the performance with 20% - 50%. The lithography architecture we build for these higher order corrections connects the dynamic scanner actuators with the angle resolved scatterometer via a separate application server. Improvements of CD uniformity are based on enabling the use of freeform intra-field dose actuator and field-to-field control of focus. The feedback control loop uses CD and focus targets placed on the production mask. For the overlay metrology we use small in-die diffraction based overlay targets. Improvements of overlay are based on using the high order intra-field correction actuators on a field-tofield basis. We use this to reduce the machine matching error, extending the heating control and extending the correction capability for process induced errors.

Enhanced methodology of focus control and monitoring on scanner tool

NASA Astrophysics Data System (ADS)

Chen, Yen-Jen; Kim, Young Ki; Hao, Xueli; Gomez, Juan-Manuel; Tian, Ye; Kamalizadeh, Ferhad; Hanson, Justin K.

2017-03-01

As the demand of the technology node shrinks from 14nm to 7nm, the reliability of tool monitoring techniques in advanced semiconductor fabs to achieve high yield and quality becomes more critical. Tool health monitoring methods involve periodic sampling of moderately processed test wafers to detect for particles, defects, and tool stability in order to ensure proper tool health. For lithography TWINSCAN scanner tools, the requirements for overlay stability and focus control are very strict. Current scanner tool health monitoring methods include running BaseLiner to ensure proper tool stability on a periodic basis. The focus measurement on YIELDSTAR by real-time or library-based reconstruction of critical dimensions (CD) and side wall angle (SWA) has been demonstrated as an accurate metrology input to the control loop. The high accuracy and repeatability of the YIELDSTAR focus measurement provides a common reference of scanner setup and user process. In order to further improve the metrology and matching performance, Diffraction Based Focus (DBF) metrology enabling accurate, fast, and non-destructive focus acquisition, has been successfully utilized for focus monitoring/control of TWINSCAN NXT immersion scanners. The optimal DBF target was determined to have minimized dose crosstalk, dynamic precision, set-get residual, and lens aberration sensitivity. By exploiting this new measurement target design, 80% improvement in tool-to-tool matching, >16% improvement in run-to-run mean focus stability, and >32% improvement in focus uniformity have been demonstrated compared to the previous BaseLiner methodology. Matching <2.4 nm across multiple NXT immersion scanners has been achieved with the new methodology of set baseline reference. This baseline technique, with either conventional BaseLiner low numerical aperture (NA=1.20) mode or advanced illumination high NA mode (NA=1.35), has also been evaluated to have consistent performance. This enhanced methodology of focus control and monitoring on multiple illumination conditions, opens an avenue to significantly reduce Focus-Exposure Matrix (FEM) wafer exposure for new product/layer best focus (BF) setup.

Quantitative approach for optimizing e-beam condition of photoresist inspection and measurement

NASA Astrophysics Data System (ADS)

Lin, Chia-Jen; Teng, Chia-Hao; Cheng, Po-Chung; Sato, Yoshishige; Huang, Shang-Chieh; Chen, Chu-En; Maruyama, Kotaro; Yamazaki, Yuichiro

2018-03-01

Severe process margin in advanced technology node of semiconductor device is controlled by e-beam metrology system and e-beam inspection system with scanning electron microscopy (SEM) image. By using SEM, larger area image with higher image quality is required to collect massive amount of data for metrology and to detect defect in a large area for inspection. Although photoresist is the one of the critical process in semiconductor device manufacturing, observing photoresist pattern by SEM image is crucial and troublesome especially in the case of large image. The charging effect by e-beam irradiation on photoresist pattern causes deterioration of image quality, and it affect CD variation on metrology system and causes difficulties to continue defect inspection in a long time for a large area. In this study, we established a quantitative approach for optimizing e-beam condition with "Die to Database" algorithm of NGR3500 on photoresist pattern to minimize charging effect. And we enhanced the performance of measurement and inspection on photoresist pattern by using optimized e-beam condition. NGR3500 is the geometry verification system based on "Die to Database" algorithm which compares SEM image with design data [1]. By comparing SEM image and design data, key performance indicator (KPI) of SEM image such as "Sharpness", "S/N", "Gray level variation in FOV", "Image shift" can be retrieved. These KPIs were analyzed with different e-beam conditions which consist of "Landing Energy", "Probe Current", "Scanning Speed" and "Scanning Method", and the best e-beam condition could be achieved with maximum image quality, maximum scanning speed and minimum image shift. On this quantitative approach of optimizing e-beam condition, we could observe dependency of SEM condition on photoresist charging. By using optimized e-beam condition, measurement could be continued on photoresist pattern over 24 hours stably. KPIs of SEM image proved image quality during measurement and inspection was stabled enough.

Solution characterization of the extracellular region of CD147 and its interaction with its enzyme ligand cyclophilin-A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlegel, Jennifer; Redzic, Jasmina S.; Porter, Christopher

2009-08-21

The CD147 receptor plays an integral role in numerous diseases by stimulating the expression of several protein families and serving as the receptor for extracellular cyclophilins, however, neither CD147 nor its interactions with its cyclophilin ligands have been well characterized in solution. CD147 is a unique protein in that it can function both at the cell membrane and after being released from cells where it continues to retain activity. Thus, the CD147 receptor functions through at least two mechanisms that include both cyclophilin-independent and cyclophilin-dependent modes of action. In regard to CD147 cyclophilin-independent activity, CD147 homophilic interactions are thought tomore » underlie its activity. In regard to CD147 cyclophilin-dependent activity, cyclophilin/CD147 interactions may represent a novel means of signaling since cyclophilins are also peptidyl-prolyl isomerases.« less

Design Optimization for the Measurement Accuracy Improvement of a Large Range Nanopositioning Stage

PubMed Central

Torralba, Marta; Yagüe-Fabra, José Antonio; Albajez, José Antonio; Aguilar, Juan José

2016-01-01

Both an accurate machine design and an adequate metrology loop definition are critical factors when precision positioning represents a key issue for the final system performance. This article discusses the error budget methodology as an advantageous technique to improve the measurement accuracy of a 2D-long range stage during its design phase. The nanopositioning platform NanoPla is here presented. Its specifications, e.g., XY-travel range of 50 mm × 50 mm and sub-micrometric accuracy; and some novel designed solutions, e.g., a three-layer and two-stage architecture are described. Once defined the prototype, an error analysis is performed to propose improvement design features. Then, the metrology loop of the system is mathematically modelled to define the propagation of the different sources. Several simplifications and design hypothesis are justified and validated, including the assumption of rigid body behavior, which is demonstrated after a finite element analysis verification. The different error sources and their estimated contributions are enumerated in order to conclude with the final error values obtained from the error budget. The measurement deviations obtained demonstrate the important influence of the working environmental conditions, the flatness error of the plane mirror reflectors and the accurate manufacture and assembly of the components forming the metrological loop. Thus, a temperature control of ±0.1 °C results in an acceptable maximum positioning error for the developed NanoPla stage, i.e., 41 nm, 36 nm and 48 nm in X-, Y- and Z-axis, respectively. PMID:26761014

Metrological challenges for measurements of key climatological observables: Oceanic salinity and pH, and atmospheric humidity. Part 1: Overview

PubMed Central

Feistel, R; Wielgosz, R; Bell, S A; Camões, M F; Cooper, J R; Dexter, P; Dickson, A G; Fisicaro, P; Harvey, A H; Heinonen, M; Hellmuth, O; Kretzschmar, H-J; Lovell-Smith, J W; McDougall, T J; Pawlowicz, R; Ridout, P; Seitz, S; Spitzer, P; Stoica, D; Wolf, H

2016-01-01

Water in its three ambient phases plays the central thermodynamic role in the terrestrial climate system. Clouds control Earth’s radiation balance, atmospheric water vapour is the strongest “greenhouse” gas, and non-equilibrium relative humidity at the air-sea interface drives evaporation and latent heat export from the ocean. On climatic time scales, melting ice caps and regional deviations of the hydrological cycle result in changes of seawater salinity, which in turn may modify the global circulation of the oceans and their ability to store heat and to buffer anthropogenically produced carbon dioxide. In this paper, together with three companion articles, we examine the climatologically relevant quantities ocean salinity, seawater pH and atmospheric relative humidity, noting fundamental deficiencies in the definitions of those key observables, and their lack of secure foundation on the International System of Units, the SI. The metrological histories of those three quantities are reviewed, problems with their current definitions and measurement practices are analysed, and options for future improvements are discussed in conjunction with the recent seawater standard TEOS-10. It is concluded that the International Bureau of Weights and Measures, BIPM, in cooperation with the International Association for the Properties of Water and Steam, IAPWS, along with other international organisations and institutions, can make significant contributions by developing and recommending state-of-the-art solutions for these long standing metrological problems in climatology. PMID:26900179

Metrological challenges for measurements of key climatological observables: oceanic salinity and pH, and atmospheric humidity. Part 1: overview

NASA Astrophysics Data System (ADS)

Feistel, R.; Wielgosz, R.; Bell, S. A.; Camões, M. F.; Cooper, J. R.; Dexter, P.; Dickson, A. G.; Fisicaro, P.; Harvey, A. H.; Heinonen, M.; Hellmuth, O.; Kretzschmar, H.-J.; Lovell-Smith, J. W.; McDougall, T. J.; Pawlowicz, R.; Ridout, P.; Seitz, S.; Spitzer, P.; Stoica, D.; Wolf, H.

2016-02-01

Water in its three ambient phases plays the central thermodynamic role in the terrestrial climate system. Clouds control Earth’s radiation balance, atmospheric water vapour is the strongest ‘greenhouse’ gas, and non-equilibrium relative humidity at the air-sea interface drives evaporation and latent heat export from the ocean. On climatic time scales, melting ice caps and regional deviations of the hydrological cycle result in changes of seawater salinity, which in turn may modify the global circulation of the oceans and their ability to store heat and to buffer anthropogenically produced carbon dioxide. In this paper, together with three companion articles, we examine the climatologically relevant quantities ocean salinity, seawater pH and atmospheric relative humidity, noting fundamental deficiencies in the definitions of those key observables, and their lack of secure foundation on the International System of Units, the SI. The metrological histories of those three quantities are reviewed, problems with their current definitions and measurement practices are analysed, and options for future improvements are discussed in conjunction with the recent seawater standard TEOS-10. It is concluded that the International Bureau of Weights and Measures, BIPM, in cooperation with the International Association for the Properties of Water and Steam, IAPWS, along with other international organizations and institutions, can make significant contributions by developing and recommending state-of-the-art solutions for these long standing metrological problems in climatology.

Certification of reference materials for the determination of alkylphenols.

PubMed

Hanari, Nobuyasu; Ishikawa, Keiichiro; Shimizu, Yoshitaka; Otsuka, Satoko; Iwasawa, Ryoko; Fujiki, Naomi; Numata, Masahiko; Yarita, Takashi; Kato, Kenji

2015-04-01

Certified reference materials (CRMs) are playing an increasingly important role in national and international standardizing activities. In Japan, primary standard solutions for analyses of endocrine disrupters are supplied under the national standards dissemination system named the Japan Calibration Service System (JCSS). For the traceability on reference materials used for preparation of the primary standard solutions based on the JCSS, the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) has developed and certified high-purity reference materials of alkylphenols as NMIJ CRMs, such as 4-n-nonylphenol, 4-tert-octylphenol, 4-n-heptylphenol, 4-tert-butylphenol, and 2,4-dichlorophenol. Thereafter, it is essential to determine the alkylphenols by using these solutions based on the JCSS for environmental monitoring and risk assessments because analytical values obtained by using the solutions can ensure the reliability and traceability of the chemical analyses.

Graphene oxide based CdSe photocatalysts: Synthesis, characterization and comparative photocatalytic efficiency of rhodamine B and industrial dye

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Trisha; Lee, Jeong-Ho; Meng, Ze-Da

Highlights: ► CdSe–graphene is synthesized by hydrothermal method. ► Three molar solutions of CdSe were used making three different composites. ► RhB and Texbrite MST-L were used as sample dye solutions. ► Texbrite MST-L is photo degraded in visible light. ► UV-spectroscopic analysis was done to measure degradation. - Abstract: CdSe–graphene composites were prepared using simple “hydrothermal method” where the graphene surface was modified using different molar solutions of cadmium selenide (CdSe) in aqueous media. The characterization of CdSe–graphene composites were studied by X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscope (SEM), and with transmission electron microscope (TEM).more » The catalytic activities of CdSe-composites were evaluated by degradation of rhodamine B (RhB) and commercial industrial dye “Texbrite MST-L (TXT-MST)” with fixed concentration. The degradation was observed by the decrease in the absorbance peak studied by UV spectrophotometer. The decrease in the dye concentration indicated catalytic degradation effect by CdSe–graphene composites.« less

Humic substances as a washing agent for Cd-contaminated soils.

PubMed

Meng, Fande; Yuan, Guodong; Wei, Jing; Bi, Dongxue; Ok, Yong Sik; Wang, Hailong

2017-08-01

Cost-effective and eco-friendly washing agents are in demand for Cd contaminated soils. Here, we used leonardite-derived humic substances to wash different types of Cd-contaminated soils, namely, a silty loam (Soil 1), a silty clay loam (Soil 2), and a sandy loam (Soil 3). Washing conditions were investigated for their effects on Cd removal efficiency. Cadmium removal was enhanced by a high humic substance concentration, long washing time, near neutral pH, and large solution/soil ratio. Based on the tradeoff between efficiency and cost, an optimum working condition was established as follows: humic substance concentration (3150 mg C/L), solution pH (6.0), washing time (2 h) and a washing solution/soil ratio (5). A single washing removed 0.55 mg Cd/kg from Soil 1 (1.33 mg Cd/kg), 2.32 mg Cd/kg from Soil 2 (6.57 mg Cd/kg), and 1.97 mg Cd/kg from Soil 3 (2.63 mg Cd/kg). Cd in effluents was effectively treated by adding a small dose of calcium hydroxide, reducing its concentration below the discharge limit of 0.1 mg/L in China. Being cost-effective and safe, humic substances have a great potential to replace common washing agents for the remediation of Cd-contaminated soils. Besides being environmentally benign, humic substances can improve soil physical, chemical, and biological properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessing the Economic and National Security Benefits from Publicly Funded Technology Investments: An IDA Round Table.

DTIC Science & Technology

1995-09-01

strong commitment today, as in the past, is that of metrology —the science and technology of measurement. Metrology has applications in the areas of...problem- solving approach: NIST has earned a worldwide reputation for impartiality and techni- cal excellence. Its competencies in metrology —the science... metrological development5 NIST’s evaluations of industry’s technology needs indicate widespread demand for enhanced measurement capabilities, and

A European Roadmap for Thermophysical Properties Metrology

NASA Astrophysics Data System (ADS)

Filtz, J.-R.; Wu, J.; Stacey, C.; Hollandt, J.; Monte, C.; Hay, B.; Hameury, J.; Villamañan, M. A.; Thurzo-Andras, E.; Sarge, S.

2015-03-01

A roadmap for thermophysical properties metrology was developed in spring 2011 by the Thermophysical Properties Working Group in the EURAMET Technical Committee in charge of Thermometry, Humidity and Moisture, and Thermophysical Properties metrology. This roadmapping process is part of the EURAMET (European Association of National Metrology Institutes) activities aiming to increase impact from national investment in European metrology R&D. The roadmap shows a shared vision of how the development of thermophysical properties metrology should be oriented over the next 15 years to meet future social and economic needs. Since thermophysical properties metrology is a very broad and varied field, the authors have limited this roadmap to the following families of properties: thermal transport properties (thermal conductivity, thermal diffusivity, etc.), radiative properties (emissivity, absorbance, reflectance, and transmittance), caloric quantities (specific heat, enthalpy, etc.), thermodynamic properties (PVT and phase equilibria properties), and temperature-dependent quantities (thermal expansion, compressibility, etc.). This roadmap identifies the main societal and economical triggers that drive developments in thermophysical properties metrology. The key topics considered are energy, environment, advanced manufacturing and processing, public safety, security, and health. Key targets that require improved thermophysical properties measurements are identified in order to address these triggers. Ways are also proposed for defining the necessary skills and the main useful means to be implemented. These proposals will have to be revised as needs and technologies evolve in the future.

Industrial graphene metrology.

PubMed

Kyle, Jennifer Reiber; Ozkan, Cengiz S; Ozkan, Mihrimah

2012-07-07

Graphene is an allotrope of carbon whose structure is based on one-atom-thick planar sheets of carbon atoms that are densely packed in a honeycomb crystal lattice. Its unique electrical and optical properties raised worldwide interest towards the design and fabrication of future electronic and optical devices with unmatched performance. At the moment, extensive efforts are underway to evaluate the reliability and performance of a number of such devices. With the recent advances in synthesizing large-area graphene sheets, engineers have begun investigating viable methodologies for conducting graphene metrology and quality control at industrial scales to understand a variety of reliability issues including defects, patternability, electrical, and physical properties. This review summarizes the current state of industrial graphene metrology and provides an overview of graphene metrology techniques. In addition, a recently developed large-area graphene metrology technique based on fluorescence quenching is introduced. For each metrology technique, the industrial metrics it measures are identified--layer thickness, edge structure, defects, Fermi level, and thermal conductivity--and a detailed description is provided as to how the measurements are performed. Additionally, the potential advantages of each technique for industrial use are identified, including throughput, scalability, sensitivity to substrate/environment, and on their demonstrated ability to achieve quantified results. The recently developed fluorescence-quenching metrology technique is shown to meet all the necessary criteria for industrial applications, rendering it the first industry-ready graphene metrology technique.

Influence of Ca and pH on the uptake and effects of Cd in Folsomia candida exposed to simplified soil solutions.

PubMed

Ardestani, Masoud M; Ortiz, Maria Diez; van Gestel, Cornelis A M

2013-08-01

The present study sought to quantify the components of a biotic ligand model (BLM) for the effects of Cd on Folsomia candida (Collembola). Assuming that soil porewater is the main route of exposure and to exclude the effects of soil particles on metal availability, animals were exposed for 7 d to different Cd concentrations between 0.1 mM and 100 mM in simplified soil solutions at different Ca concentrations (0.2 mM, 0.8 mM, 3.2 mM, and 12.8 mM) or at different pH (5.0, 6.0, and 7.0). Higher Ca concentrations decreased the toxicity of Cd (adult survival) in test solutions, whereas toxicity was slightly lower at pH 7 and 6 than at pH 5, suggesting a mitigating effect of Ca and to a lesser extent pH on Cd toxicity to F. candida. Internal Cd concentrations in the animals increased with increasing exposure level but were significantly reduced by increasing Ca concentrations and were not significantly affected by pH. By using Langmuir isotherms, binding constants for Cd, Ca, and protons and the fraction of binding sites occupied by Cd were calculated and used to predict effects of Cd on survival. Predicted toxicity showed a good agreement with measured responses when Ca and pH were used as separate factors or combined together. The present study shows indications of protective effects of Ca but less of protons on the toxicity and uptake of Cd in F. candida on exposure to simplified soil solutions, which can be described using the principles of a biotic ligand model. Copyright © 2013 SETAC.

A facile synthesis of Zn(x)Cd(1-x)S/CNTs nanocomposite photocatalyst for H2 production.

PubMed

Wang, Lei; Yao, Zhongping; Jia, Fangzhou; Chen, Bin; Jiang, Zhaohua

2013-07-21

The sulfide solid solution has become a promising and important visible-light-responsive photocatalyst for hydrogen production nowadays. Zn(x)Cd(1-x)S/CNT nanocomposites were synthesized to improve the dispersion, adjust the energy band gap, and enhance the separation of the photogenerated electrons and holes. The as-prepared photocatalysts were characterized by scanning electron-microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance spectra (UV-visible), respectively. And the effects of CNTs on structure, composition and optical absorption property of the sulfide solid solutions were investigated along with their inherent relationships. For Zn0.83Cd0.17S/CNTs, sulfide solid solution is assembled along the CNTs orderly, with a diameter of 100 nm or so. XPS analysis shows that there is bonding effect between the solid solutions and the CNTs due to the strong adsorption of Zn(2+) and Cd(2+) on the surface of CNTs. There are two obvious absorption edges for Zn0.83Cd0.17S/CNTs, corresponding to two kinds of sulfide solid solutions with different molar ratios of Zn/Cd. The hybridization of solid solutions with CNTs makes the absorption spectrum red shift. The photocatalytic property was evaluated by splitting Na2S + Na2SO3 solution into H2, and the highest rate of H2 evolution of 6.03 mmol h(-1) g(-1) was achieved over Zn0.83Cd0.17S/CNTs. The high activity of photocatalytic H2 production is attributed to the following factors: (1) the optimum band gap and a moderate position of the conduction band (which needs to match the irradiation spectrum of the Xe lamp best), (2) the efficient separation of photogenerated electrons and holes by hybridization, and (3) the improvement of the dispersion of nanocomposites by assembling along the CNTs as well.

Laser Truss Sensor for Segmented Telescope Phasing

NASA Technical Reports Server (NTRS)

Liu, Duncan T.; Lay, Oliver P.; Azizi, Alireza; Erlig, Herman; Dorsky, Leonard I.; Asbury, Cheryl G.; Zhao, Feng

2011-01-01

A paper describes the laser truss sensor (LTS) for detecting piston motion between two adjacent telescope segment edges. LTS is formed by two point-to-point laser metrology gauges in a crossed geometry. A high-resolution (<30 nm) LTS can be implemented with existing laser metrology gauges. The distance change between the reference plane and the target plane is measured as a function of the phase change between the reference and target beams. To ease the bandwidth requirements for phase detection electronics (or phase meter), homodyne or heterodyne detection techniques have been used. The phase of the target beam also changes with the refractive index of air, which changes with the air pressure, temperature, and humidity. This error can be minimized by enclosing the metrology beams in baffles. For longer-term (weeks) tracking at the micron level accuracy, the same gauge can be operated in the absolute metrology mode with an accuracy of microns; to implement absolute metrology, two laser frequencies will be used on the same gauge. Absolute metrology using heterodyne laser gauges is a demonstrated technology. Complexity of laser source fiber distribution can be optimized using the range-gated metrology (RGM) approach.

Metrology in electricity and magnetism: EURAMET activities today and tomorrow

NASA Astrophysics Data System (ADS)

Piquemal, F.; Jeckelmann, B.; Callegaro, L.; Hällström, J.; Janssen, T. J. B. M.; Melcher, J.; Rietveld, G.; Siegner, U.; Wright, P.; Zeier, M.

2017-10-01

Metrology dedicated to electricity and magnetism has changed considerably in recent years. It encompasses almost all modern scientific, industrial, and societal challenges, e.g. the revision of the International System of Units, the profound transformation of industry, changes in energy use and generation, health, and environment, as well as nanotechnologies (including graphene and 2D materials) and quantum engineering. Over the same period, driven by the globalization of worldwide trade, the Mutual Recognition Arrangement (referred to as the CIPM MRA) was set up. As a result, the regional metrology organizations (RMOs) of national metrology institutes have grown in significance. EURAMET is the European RMO and has been very prominent in developing a strategic research agenda (SRA) and has established a comprehensive research programme. This paper reviews the highlights of EURAMET in electrical metrology within the European Metrology Research Programme and its main contributions to the CIPM MRA. In 2012 EURAMET undertook an extensive roadmapping exercise for proposed activities for the next decade which will also be discussed in this paper. This work has resulted in a new SRA of the second largest European funding programme: European Metrology Programme for Innovation and Research.

Strong mechanical adhesion of gold electroless contacts on CdZnTe deposited by alcoholic solutions

NASA Astrophysics Data System (ADS)

Benassi, G.; Nasi, L.; Bettelli, M.; Zambelli, N.; Calestani, D.; Zappettini, A.

2017-02-01

CdZnTe crystals are nowadays employed as X-ray detectors for a number of applications, such as medical imaging, security, and environmental monitoring. One of the main difficulties connected with CdZnTe-based detector processing is the poor contact adhesion that affect bonding procedures and device long term stability. We have shown that it is possible to obtain mechanically stable contacts by common electroless deposition using alcoholic solutions instead of water solutions. The contacts show blocking current-voltage characteristic that is required for obtaining spectroscopic detectors. Nanoscale-resolved chemical analysis indicated that the improved mechanical adhesion is due to a better control of the stoichiometry of the CdZnTe layer below the contact.

The preparation and degradation performance of CdS photocatalysts to methyl orange solution.

PubMed

Duan, Limei; Zhao, Weiqiang; Xu, Ling; Chen, Xiaohong; Lita, A; Liu, Zongrui

2013-03-01

In this paper, the CdS samples were prepared using thiourea or sodium sulfide as sulfur source by hydrothermal or solvothermal synthesis method, the results of XRD, TEM and SEM showed all the samples belong to hexagonal CdS nano-material with different morphologies. Using the degradation of methyl orange solution as a model reaction, the photocatalytic performance of different CdS samples was measured, and the samples prepared using thiourea as sulfur source exhibited better photocatalytic activity than those using sodium sulfide as sulfur source. The factors on degradation effect were discussed including the pH value of degradation system and the type of light source. The degradation effect of CdS samples increased with the pH value decreased, and the degradation effect was better when the methyl orange solution was irradiated under sunlight than under 250 W mercury lamp.

High efficiency solution processed sintered CdTe nanocrystal solar cells: the role of interfaces.

PubMed

Panthani, Matthew G; Kurley, J Matthew; Crisp, Ryan W; Dietz, Travis C; Ezzyat, Taha; Luther, Joseph M; Talapin, Dmitri V

2014-02-12

Solution processing of photovoltaic semiconducting layers offers the potential for drastic cost reduction through improved materials utilization and high device throughput. One compelling solution-based processing strategy utilizes semiconductor layers produced by sintering nanocrystals into large-grain semiconductors at relatively low temperatures. Using n-ZnO/p-CdTe as a model system, we fabricate sintered CdTe nanocrystal solar cells processed at 350 °C with power conversion efficiencies (PCE) as high as 12.3%. JSC of over 25 mA cm(-2) are achieved, which are comparable or higher than those achieved using traditional, close-space sublimated CdTe. We find that the VOC can be substantially increased by applying forward bias for short periods of time. Capacitance measurements as well as intensity- and temperature-dependent analysis indicate that the increased VOC is likely due to relaxation of an energetic barrier at the ITO/CdTe interface.

Search for general relativistic effects in table-top displacement metrology

NASA Technical Reports Server (NTRS)

Halverson, Peter G.; Macdonald, Daniel R.; Diaz, Rosemary T.

2004-01-01

As displacement metrology accuracy improves, general relativistic effects will become noticeable. Metrology gauges developed for the Space Interferometry Mission were used to search for locally anisotropic space-time, with a null result at the 10 to the negative tenth power level.

Test Evaluation and Modification of Prototype Rotating Gravity Gradiometer

DTIC Science & Technology

1975-07-01

RECOMMENEATIONS 3 4.0 BEARINGS 6 4.1 Design 6 4.2 Metrology 6 4.3 Preassembly 14 5.0 TEST RIG 17 5.1 Design 17 5.2 Metrology 21 5.3 Assembly and...print requirements of 5 \\i inches TIR max. However, because of available (stare-of-the-art) metrology equipment limitations, no conclusion as to...gravity gradiometer are contained in Shaker Research Corporation drawing series 101 (see Appendix I), 4.2 Metrology The production of the

Speciation of cadmium and zinc with application to soil solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holm, P.E.; Christensen, T.H.; Tjell, J.C.

1995-01-01

A two-part method has been developed for determination of Cd and Zn species in 50-mL soil solution samples containing low concentrations of Cd and Zn (1-10 {mu}g Cd L{sup -1} and 50-1000 {mu}g Zn L{sup -1}). The method uses two cation exchange resins (Amberlite CG 120 and Chelex 100) in a batch-column-batch procedure and relies on analytical determinations of Cd and Zn by graphite furnace atomic absorption spectrophotometry. The first part (batch) of the method allows determination of free divalent Cd{sup 2+} and Zn{sup 2+}. This part is experimentally sensitive to cation concentrations and ionic strength and these parameters shouldmore » be controlled during the experimental procedures. However, it is shown that Cd and Zn concentrations and pH do not influence the method. Speciations performed on samples containing chloride and sulfate were in accordance with theoretical calculations. The second part (column-batch) of the method operationally separates the complexed fraction into labile complexes, slowly labile complexes, and stable complexes. Chloro complexes were identified as labile complexes, while EDTA complexes were identified as stable complexes. The method works well with relatively small volumes of sample solutions and at low metal concentrations and may be useful in characterization of Cd and Zn in soil solutions. 12 refs., 6 figs., 3 tabs.« less

Using electrocoagulation for metal and chelant separation from washing solution after EDTA leaching of Pb, Zn and Cd contaminated soil.

PubMed

Pociecha, Maja; Lestan, Domen

2010-02-15

Electrocoagulation with an Al sacrificial anode was tested for the separation of chelant and heavy metals from a washing solution obtained after leaching Pb (3200 mg kg(-1)), Zn (1100 mg kg(-1)), and Cd (21 mg kg(-1)) contaminated soil with EDTA. In the electrochemical process, the sacrificial anode corroded to release Al(3+) which served as coagulant for precipitation of chelant and metals. A constant current density of 16-128 mAc m(-2) applied between the Al anode and the stainless-steel cathode removed up to 95% Pb, 68% Zn and 66% Cd from the soil washing solution. Approximately half of the initial EDTA remained in the washing solution after treatment, up to 16.3% of the EDTA was adsorbed on Al coagulant and precipitated, the rest of the EDTA was degraded by anodic oxidation. In a separate laboratory-scale remediation experiment, we leached a soil with 40 mmol EDTA per kg of soil and reused the washing solution (after electrocoagulation) in a closed loop. It removed 53% of Pb, 26% of Zn and 52% of Cd from the soil. The discharge solution was clear and colourless, with pH 7.52 and 170 mg L(-1) Pb, 50 mg L(-1) Zn, 1.5 mg L(-1) Cd and 11 mM EDTA.

education | News

Science.gov Websites

, agencies and professional associations. Introduction to metrology career day at St. Charles North High St. Charles North High School students to talk with them about metrology. Here, use a portable , a Fermilab metrology technical specialist, visited St. Charles North High School students to talk

Search for general relativistic effects in table-top displacement metrology

NASA Technical Reports Server (NTRS)

Halverson, Peter G.; Diaz, Rosemary T.; Macdonald, Daniel R.

2004-01-01

As displacement metrology accuracy improves, general relativistic effects will become noticeable. Metrology gauges developed for the Space Interferometry Mission, were used to search for locally anisotropic space-time, with a null result at the 10 to the negative 10th power level.

Coherent X-ray beam metrology using 2D high-resolution Fresnel-diffraction analysis.

PubMed

Ruiz-Lopez, M; Faenov, A; Pikuz, T; Ozaki, N; Mitrofanov, A; Albertazzi, B; Hartley, N; Matsuoka, T; Ochante, Y; Tange, Y; Yabuuchi, T; Habara, T; Tanaka, K A; Inubushi, Y; Yabashi, M; Nishikino, M; Kawachi, T; Pikuz, S; Ishikawa, T; Kodama, R; Bleiner, D

2017-01-01

Direct metrology of coherent short-wavelength beamlines is important for obtaining operational beam characteristics at the experimental site. However, since beam-time limitation imposes fast metrology procedures, a multi-parametric metrology from as low as a single shot is desirable. Here a two-dimensional (2D) procedure based on high-resolution Fresnel diffraction analysis is discussed and applied, which allowed an efficient and detailed beamline characterization at the SACLA XFEL. So far, the potential of Fresnel diffraction for beamline metrology has not been fully exploited because its high-frequency fringes could be only partly resolved with ordinary pixel-limited detectors. Using the high-spatial-frequency imaging capability of an irradiated LiF crystal, 2D information of the coherence degree, beam divergence and beam quality factor M 2 were retrieved from simple diffraction patterns. The developed beam metrology was validated with a laboratory reference laser, and then successfully applied at a beamline facility, in agreement with the source specifications.

Analysis of key technologies for virtual instruments metrology

NASA Astrophysics Data System (ADS)

Liu, Guixiong; Xu, Qingui; Gao, Furong; Guan, Qiuju; Fang, Qiang

2008-12-01

Virtual instruments (VIs) require metrological verification when applied as measuring instruments. Owing to the software-centered architecture, metrological evaluation of VIs includes two aspects: measurement functions and software characteristics. Complexity of software imposes difficulties on metrological testing of VIs. Key approaches and technologies for metrology evaluation of virtual instruments are investigated and analyzed in this paper. The principal issue is evaluation of measurement uncertainty. The nature and regularity of measurement uncertainty caused by software and algorithms can be evaluated by modeling, simulation, analysis, testing and statistics with support of powerful computing capability of PC. Another concern is evaluation of software features like correctness, reliability, stability, security and real-time of VIs. Technologies from software engineering, software testing and computer security domain can be used for these purposes. For example, a variety of black-box testing, white-box testing and modeling approaches can be used to evaluate the reliability of modules, components, applications and the whole VI software. The security of a VI can be assessed by methods like vulnerability scanning and penetration analysis. In order to facilitate metrology institutions to perform metrological verification of VIs efficiently, an automatic metrological tool for the above validation is essential. Based on technologies of numerical simulation, software testing and system benchmarking, a framework for the automatic tool is proposed in this paper. Investigation on implementation of existing automatic tools that perform calculation of measurement uncertainty, software testing and security assessment demonstrates the feasibility of the automatic framework advanced.

Leaching variations of heavy metals in chelator-assisted phytoextraction by Zea mays L. exposed to acid rainfall.

PubMed

Lu, Yayin; Luo, Dinggui; Liu, Lirong; Tan, Zicong; Lai, An; Liu, Guowei; Li, Junhui; Long, Jianyou; Huang, Xuexia; Chen, Yongheng

2017-11-01

Chelant-enhanced phytoextraction method has been put forward as an effective soil remediation method, whereas the heavy metal leaching could not be ignored. In this study, a cropping-leaching experiment, using soil columns, was applied to study the metal leaching variations during assisted phytoextraction of Cd- and Pb-polluted soils, using seedlings of Zea mays, applying three different chelators (EDTA, EDDS, and rhamnolipid), and artificial rainfall (acid rainfall or normal rainfall). It showed that artificial rainfall, especially artificial acid rain, after chelator application led to the increase of heavy metals in the leaching solution. EDTA increased both Cd and Pb concentrations in the leaching solution, obviously, whereas EDDS and rhamnolipid increased Cd concentration but not Pb. The amount of Cd and Pb decreased as the leaching solution increased, the patterns as well matched LRMs (linear regression models), with R-square (R 2 ) higher than 90 and 82% for Cd and Pb, respectively. The maximum cumulative Cd and Pb in the leaching solutions were 18.44 and 16.68%, respectively, which was amended by EDTA and acid rainwater (pH 4.5), and followed by EDDS (pH 4.5), EDDS (pH 6.5), rhamnolipid (0.5 g kg -1 soil, pH 4.5), and rhamnolipid (pH 6.5).

SEM image quality enhancement technology for bright field mask

NASA Astrophysics Data System (ADS)

Fukuda, Naoki; Chihara, Yuta; Shida, Soichi; Ito, Keisuke

2013-09-01

Bright-field photomasks are used to print small contact holes via ArF immersion multiple patterning lithography. There are some technical difficulties when small floating dots are to be measured by SEM tools because of a false imaging shadow. However, a new scan technology of Multi Vision Metrology SEMTM E3630 presents a solution for this issue. The combination of new scan technology and the other MVM-SEM® functions can provide further extended applications with more accurate measurement results.

Electrochemical EDTA recycling after soil washing of Pb, Zn and Cd contaminated soil.

PubMed

Pociecha, Maja; Kastelec, Damijana; Lestan, Domen

2011-08-30

Recycling of chelant decreases the cost of EDTA-based soil washing. Current methods, however, are not effective when the spent soil washing solution contains more than one contaminating metal. In this study, we applied electrochemical treatment of the washing solution obtained after EDTA extraction of Pb, Zn and Cd contaminated soil. A sacrificial Al anode and stainless steel cathode in a conventional electrolytic cell at pH 10 efficiently removed Pb from the solution. The method efficiency, specific electricity and Al consumption were significantly higher for solutions with a higher initial metal concentration. Partial replacement of NaCl with KNO(3) as an electrolyte (aggressive Cl(-) are required to prevent passivisation of the Al anode) prevented EDTA degradation during the electrolysis. The addition of FeCl(3) to the acidified washing solution prior to electrolysis improved Zn removal. Using the novel method 98, 73 and 66% of Pb, Zn and Cd, respectively, were removed, while 88% of EDTA was preserved in the treated washing solution. The recycled EDTA retained 86, 84 and 85% of Pb, Zn and Cd extraction potential from contaminated soil, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Effects of EDTA and low molecular weight organic acids on soil solution properties of a heavy metal polluted soil.

PubMed

Wu, L H; Luo, Y M; Christie, P; Wong, M H

2003-02-01

A pot experiment was conducted to study the effects of EDTA and low molecular weight organic acids (LMWOA) on the pH, total organic carbon (TOC) and heavy metals in the soil solution in the rhizosphere of Brassica juncea grown in a paddy soil contaminated with Cu, Zn, Pb and Cd. The results show that EDTA and LMWOA have no effect on the soil solution pH. EDTA addition significantly increased the TOC concentrations in the soil solution. The TOC concentrations in treatments with EDTA were significantly higher than those in treatments with LMWOA. Adding 3 mmol kg(-1) EDTA to the soil markedly increased the total concentrations of Cu, Zn, Pb and Cd in the soil solution. Compared to EDTA, LMWOA had a very small effect on the metal concentrations. Total concentrations in the soil solution followed the sequence: EDTA > citric acid (CA) approximately oxalic acid (OA) approximately malic acid (MA) for Cu and Pb; EDTA > MA > CA approximately OA for Zn; and EDTA > MA > CA > OA for Cd. The labile concentrations of Cu, Zn, Pb and Cd showed similar trends to the total concentrations.

Portable traceability solution for ground-based calibration of optical instruments

NASA Astrophysics Data System (ADS)

El Gawhary, Omar; van Veghel, Marijn; Kenter, Pepijn; van der Leden, Natasja; Dekker, Paul; Revtova, Elena; Heemskerk, Maurice; Trarbach, André; Vink, Ramon; Doyle, Dominic

2017-11-01

We present a portable traceability solution for the ground-based optical calibration of earth observation (EO) instruments. Currently, traceability for this type of calibration is typically based on spectral irradiance sources (e.g. FEL lamps) calibrated at a national metrology institute (NMI). Disadvantages of this source-based traceability are the inflexibility in operating conditions of the source, which are limited to the settings used during calibration at the NMI, and the susceptibility to aging, which requires frequent recalibrations, and which cannot be easily checked on-site. The detector-based traceability solution presented in this work uses a portable filter radiometer to calibrate light sources onsite, immediately before and after, or even during instrument calibration. The filter radiometer itself is traceable to the primary standard of radiometry in the Netherlands. We will discuss the design and realization, calibration and performance verification.

Surface contouring by controlled application of processing fluid using Marangoni effect

DOEpatents

Rushford, Michael C.; Britten, Jerald A.

2003-04-29

An apparatus and method for modifying the surface of an object by contacting said surface with a liquid processing solution using the liquid applicator geometry and Marangoni effect (surface tension gradient-driven flow) to define and confine the dimensions of the wetted zone on said object surface. In particular, the method and apparatus involve contouring or figuring the surface of an object using an etchant solution as the wetting fluid and using realtime metrology (e.g. interferometry) to control the placement and dwell time of this wetted zone locally on the surface of said object, thereby removing material from the surface of the object in a controlled manner. One demonstrated manifestation is in the deterministic optical figuring of thin glasses by wet chemical etching using a buffered hydrofluoric acid solution and Marangoni effect.

Apparatus For Etching Or Depositing A Desired Profile Onto A Surface

DOEpatents

Rushford, Michael C.; Britten, Jerald A.

2004-05-25

An apparatus and method for modifying the surface of an object by contacting said surface with a liquid processing solution using the liquid applicator geometry and Marangoni effect (surface tension gradient-driven flow) to define and confine the dimensions of the wetted zone on said object surface. In particular, the method and apparatus involve contouring or figuring the surface of an object using an etchant solution as the wetting fluid and using real-time metrology (e.g. interferometry) to control the placement and dwell time of this wetted zone locally on the surface of said object, thereby removing material from the surface of the object in a controlled manner. One demonstrated manifestation is in the deterministic optical figuring of thin glasses by wet chemical etching using a buffered hydrofluoric acid solution and Marangoni effect.

Simultaneous adsorption of Cd²⁺ and BPA on amphoteric surfactant activated montmorillonite.

PubMed

Liu, Chongmin; Wu, Pingxiao; Zhu, Yajie; Tran, Lytuong

2016-02-01

The study mainly investigated the simultaneous adsorption of bisphenol A (BPA) and Cd(2+) from aqueous solution on octadecane-betaine modified montmorillonite (BS-Mt). The characteristics of the obtained materials were analyzed by X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Specific surface area (BET) and Scanning electron microscopy/Energy disperse spectroscopy (SEM/EDS), confirming that BS-18 was successfully introduced into Mt. Also, factors including initial solution pH, initial Cd(2+)/BPA concentration, contact time and adsorbent dosage on the adsorption processes were shown to be crucial for Cd(2+) adsorption, whereas had negligible effects on BPA adsorption. In this study, we found that pseudo-second-order model fitted well with the adsorption kinetic studies for both Cd(2+) and BPA with an equilibrium time of 24 h. The Cd(2+) and BPA adsorption isotherm could be well described by Freundlich model and Langmuir model, respectively. On the basis of kinetic models, the maximum adsorption capacity of Cd(2+) in aqueous solution was slightly enhanced after modification, indicating that Cd(2+) adsorption on BS-Mt was mainly attributed to direct electrostatic attraction and the chelate reaction, while the dramatic enhancement of maximum adsorption capacity for BPA was due to the hydrophobic interaction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spontaneous Self-Assembly of Polymeric Nanoparticles in Aqueous Media: New Insights From Microfluidics, In Situ Size Measurements, and Individual Particle Tracking.

PubMed

Li, Xue; Salzano, Giuseppina; Zhang, Jiwen; Gref, Ruxandra

2017-01-01

Supramolecular cyclodextrin-based nanoparticles (CD-NPs) mediated by host-guest interactions have gained increased popularity because of their "green" and simple preparation procedure, as well as their versatility in terms of inclusion of active molecules. Herein, we showed that original CD-NPs of around 100 nm are spontaneously formed in water, by mixing 2 aqueous solutions of (1) a CD polymer and (2) dextran grafted with benzophenone moieties. For the first time, CD-NPs were instantaneously produced in a microfluidic interaction chamber by mixing 2 aqueous solutions of neutral polymers, in the absence of organic solvents. Whatever the mixing conditions, CD-NPs with narrow size distributions were immediately formed upon contact of the 2 polymeric solutions. In situ size measurements showed that the CD-NPs were spontaneously formed. Nanoparticle tracking analysis was used to individually follow the CD-NPs in their Brownian motions, to gain insights on their size distribution, concentration, and stability on extreme dilution. Nanoparticle tracking analysis allowed to establish that despite their non-covalent nature, and the CD-NPs were remarkably stable in terms of concentration and size distribution, even on extreme dilution (concentrations as low as 100 ng/mL). Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Three-dimensional profile extraction from CD-SEM image and top/bottom CD measurement by line-edge roughness analysis

NASA Astrophysics Data System (ADS)

Yamaguchi, Atsuko; Ohashi, Takeyoshi; Kawasaki, Takahiro; Inoue, Osamu; Kawada, Hiroki

2013-04-01

A new method for calculating critical dimension (CDs) at the top and bottom of three-dimensional (3D) pattern profiles from a critical-dimension scanning electron microscope (CD-SEM) image, called as "T-sigma method", is proposed and evaluated. Without preparing a library of database in advance, T-sigma can estimate a feature of a pattern sidewall. Furthermore, it supplies the optimum edge-definition (i.e., threshold level for determining edge position from a CDSEM signal) to detect the top and bottom of the pattern. This method consists of three steps. First, two components of line-edge roughness (LER); noise-induced bias (i.e., LER bias) and unbiased component (i.e., bias-free LER) are calculated with set threshold level. Second, these components are calculated with various threshold values, and the threshold-dependence of these two components, "T-sigma graph", is obtained. Finally, the optimum threshold value for the top and the bottom edge detection are given by the analysis of T-sigma graph. T-sigma was applied to CD-SEM images of three kinds of resist-pattern samples. In addition, reference metrology was performed with atomic force microscope (AFM) and scanning transmission electron microscope (STEM). Sensitivity of CD measured by T-sigma to the reference CD was higher than or equal to that measured by the conventional edge definition. Regarding the absolute measurement accuracy, T-sigma showed better results than the conventional definition. Furthermore, T-sigma graphs were calculated from CD-SEM images of two kinds of resist samples and compared with corresponding STEM observation results. Both bias-free LER and LER bias increased as the detected edge point moved from the bottom to the top of the pattern in the case that the pattern had a straight sidewall and a round top. On the other hand, they were almost constant in the case that the pattern had a re-entrant profile. T-sigma will be able to reveal a re-entrant feature. From these results, it is found that T-sigma method can provide rough cross-sectional pattern features and achieve quick, easy and accurate measurements of top and bottom CD.

Cadmium uptake by Pinus resinosa Ait. pollen and the effect on cation release and membrane permeability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strickland, R.C.; Chaney, W.R.; Lamoreaux, R.J.

Cadmium uptake by red pine (Pinus resinosa Ait.) pollen from a graded series of Cd/sup 2 +/ solutions (0 to 2.88 microequivalents per 50 milligrams pollen) and its effect on membrane integrity were examined by atomic absorption spectroscopy. Uptake was strongly dependent on Cd/sup 2 +/ concentration and was limited to adsorption and cation exchange in pollen walls during a 3-hour measurement period. Good correlation between measured Cd/sup 2 +/ uptake and that predicted by the Langmuir and Freundlich isotherm equations indicated the adsorptive nature of Cd/sup 2 +/ uptake. While substantial quantities of Ca/sup 2 +/ and Mg/sup 2more » +/ were released by exchange mechanisms concurrent with Cd/sup 2 +/ uptake, there was no evidence for leakage of cations due to membrane impairment as indicated by a poor correlation between Cd/sup 2 +/ uptake and K/sup +/ efflux. Virtually all Cd/sup 2 +/ removed from solution was freely exchangeable with 0.5 millimolar CaCl/sub 2/ and demonstrated that Cd/sup 2 +/ did not readily enter pine pollen but was adsorbed on the pollen wall. Ultraviolet transmission spectra of treatment solutions and analyses of phosphate and reducing sugar efflux also indicated that the potent toxicity of Cd/sup 2 +/ to pollen germination and germ tube elongation was not the result of membrane damage.« less

Polyaspartate extraction of cadmium ions from contaminated soil: Evaluation and optimization using central composite design.

PubMed

Mu'azu, Nuhu Dalhat; Haladu, Shamsuddeen A; Jarrah, Nabeel; Zubair, Mukarram; Essa, Mohammad H; Ali, Shaikh A

2018-01-15

The occurrences of heavy metal contaminated sites and soils and the need for devising environmentally friendly solutions have become global issues of serious concern. In this study, polyaspartate (a highly biodegradable agent) was synthesized using L-Aspartic acid via a new modified thermal procedure and employed for extraction of cadmium ions (Cd) from contaminated soil. Response surface methodology approach using 3 5 full faced centered central composite design was employed for modeling, evaluating and optimizing the influence of polyaspartate concentration (36-145mM), polyaspartate/soil ratio (5-25), initial heavy metal concentration (100-500mg/kg), initial pH (3-6) and extraction time (6-24h) on Cd ions extracted into the polyaspartate solution and its residual concentration in the treated soil. The Cd extraction efficacy obtained reached up to 98.8%. Increase in Cd extraction efficiency was associated with increase in the polyaspartate and Cd concentration coupled with lower polyaspertate/soil ratio and initial pH. Under the optimal conditions characterized with minimal utilization of the polyaspartate and high Cd ions removal, the extractible Cd in the polyaspartate solution reached up to 84.4mg/L which yielded 85% Cd extraction efficacy. This study demonstrates the suitability of using polyaspartate as an effective environmentally friendly chelating agent for Cd extraction from contaminated soils. Copyright © 2017 Elsevier B.V. All rights reserved.

Differences of cadmium absorption and accumulation in selected vegetable crops.

PubMed

Ni, Wu-Zhong; Yang, Xiao-E; Long, Xin-Xian

2002-07-01

A pot experiment and a sandy culture experiment grown with three vegetable crops of Chinese cabbage (B. chinensis L., cv. Zao-Shu 5), winter greens (B. var. rosularis Tsen et Lee, cv. Shang-Hai-Qing) and celery (A. graveolens L. var. dulce DC., cv. Qing-Qin) were conducted, respectively. The initial soil and four incubated soils with different extractable Cd (0.15, 0.89, 1.38, 1.84 and 2.30 mg Cd/kg soil) were used for the pot experiment. Five treatments were designed (0, 0.0625, 0.125, 0.250 and 0.500 mg Cd/L) in nutrient solution in the sandy culture experiment. Each treatment in pot and sandy culture experiments was trireplicated. The objectives of the study were to examine Cd accumulation in edible parts of selected vegetable crops, its correlation with Cd concentrations in vegetable garden soil or in nutrient solution, and evaluate the criteria of Cd pollution in vegetable garden soil and in nutrient solution based on the hygienic limit of Cd in vegetables. Cadmium concentrations in edible parts of the three selected vegetable crops were as follows: 0.01-0.15 mg/kg fresh weight for Chinese cabbage, 0.02-0.17 mg/kg fresh weight for winter greens, and 0.02-0.24 mg/kg fresh weight for celery in the pot experiment, and 0.1-0.4 mg/kg fresh weight for Chinese cabbage, 0.1-1.4 mg/kg fresh weight for winter greens, and 0.05-0.5 mg/kg fresh weight for celery in the pot experiment (except no-Cd treatment). The order of the three test vegetable crops for cadmium accumulation in the edible parts was celery > winter greens > Chinese cabbage in both the pot experiment and the sandy culture experiment. Cadmium accumulation in edible parts or roots of the vegetable crops increased with increasing of cadmium concentration in the medium (soil or nutrient solution). And cadmium concentrations in edible parts of the test vegetable crops were significantly linearly related to the Cd levels in the growth media (soil and nutrient solution). Based on the regression equations established and the limit of cadmium concentration in vegetable products, the thresholds of Cd concentration in the growth medium evaluated was as follows: 0.5 mg/kg soil of extractable Cd for soil and 0.02 mg/L for nutrient solution. The high capacity for cadmium accumulation in the edible parts of different vegetable crops together with the absence of visual symptoms implies a potential danger for humans.

Issues of Teaching Metrology in Higher Education Institutions of Civil Engineering in Russia

ERIC Educational Resources Information Center

Pukharenko, Yurii Vladimirovich; Norin, Veniamin Aleksandrovich

2017-01-01

The work analyses the training process condition in teaching the discipline "Metrology, Standardization, Certification and Quality Control." It proves that the current educational standard regarding the instruction of the discipline "Metrology, Standardization, Certification and Quality Control" does not meet the needs of the…

Metrology Careers: Jobs for Good Measure

ERIC Educational Resources Information Center

Liming, Drew

2009-01-01

What kind of career rewards precision and accuracy? One in metrology--the science of measurement. By evaluating and calibrating the technology in people's everyday lives, metrologists keep their world running smoothly. Metrology is used in the design and production of almost everything people encounter daily, from the cell phones in their pockets…

Radioactive waste management: review on clearance levels and acceptance criteria legislation, requirements and standards.

PubMed

Maringer, F J; Suráň, J; Kovář, P; Chauvenet, B; Peyres, V; García-Toraño, E; Cozzella, M L; De Felice, P; Vodenik, B; Hult, M; Rosengård, U; Merimaa, M; Szücs, L; Jeffery, C; Dean, J C J; Tymiński, Z; Arnold, D; Hinca, R; Mirescu, G

2013-11-01

In 2011 the joint research project Metrology for Radioactive Waste Management (MetroRWM)(1) of the European Metrology Research Programme (EMRP) started with a total duration of three years. Within this project, new metrological resources for the assessment of radioactive waste, including their calibration with new reference materials traceable to national standards will be developed. This paper gives a review on national, European and international strategies as basis for science-based metrological requirements in clearance and acceptance of radioactive waste. © 2013 Elsevier Ltd. All rights reserved.

Adjustment method for embedded metrology engine in an EM773 series microcontroller.

PubMed

Blazinšek, Iztok; Kotnik, Bojan; Chowdhury, Amor; Kačič, Zdravko

2015-09-01

This paper presents the problems of implementation and adjustment (calibration) of a metrology engine embedded in NXP's EM773 series microcontroller. The metrology engine is used in a smart metering application to collect data about energy utilization and is controlled with the use of metrology engine adjustment (calibration) parameters. The aim of this research is to develop a method which would enable the operators to find and verify the optimum parameters which would ensure the best possible accuracy. Properly adjusted (calibrated) metrology engines can then be used as a base for variety of products used in smart and intelligent environments. This paper focuses on the problems encountered in the development, partial automatisation, implementation and verification of this method. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Two-photon fluorescence anisotropy imaging

NASA Astrophysics Data System (ADS)

Li, Wei; Wang, Yi; Shao, Hanrong; He, Yonghong; Ma, Hui

2006-09-01

We have developed a novel method for imaging the fluorescence intensity and anisotropy by two-photon fluorescence microscopy and tested its capability in biological application. This method is applied to model sample including FITC and FITC-CD44 antibody solution and also FITC-CD44 stained cells. The fluorescence anisotropy (FA) of FITC-CD44ab solution is higher than the FITC solution with the same concentration. The fluorescence in cell sample has even higher FA than in solution because the rotation diffusion is restrained in membrane. The method is employed to study the effect of berberine a kind of Chinese medicine, on tumor metastasis. The results indicated that tumor cell membrane fluidity is decreasing with increasing the concentration of berberine in culture medium.

Growth And Characterization Of LPE CdHgTe/CdZnTe/CdZnTe Structure

NASA Astrophysics Data System (ADS)

Pelliciari, B.; Chamonal, J. P.; Destefanis, G. L.; Dicioccio, L.

1988-05-01

The liquid phase epitaxial technique is used to grow Hgl_x Cdx Te (x = .23) from a Te - rich solution onto a Cdl_y ZnyTe (y = .04) buffer layer grown from a Te-rich solution onto a Cdi_yZnyTe bulk substrate in an open tube multibin horizontal slider apparatus.Growth conditions and physical characterizations of both the buffer layer and the CdHgTe layer are given ; electrical properties of the CdHgTe layer are also presen-ted. PV detectors were successfully obtained on such a structure using an ion-implanted technology and their characteristics at 77 K for a 10.1 ,um cut-off wavelength are given.

Thiolated graphene - a new platform for anchoring CdSe quantum dots for hybrid heterostructures

NASA Astrophysics Data System (ADS)

Debgupta, Joyashish; Pillai, Vijayamohanan K.

2013-04-01

Effective organization of small CdSe quantum dots on graphene sheets has been achieved by a simple solution exchange with thiol terminated graphene prepared by diazonium salt chemistry. This generic methodology of CdSe QD attachment to any graphene surface has remarkable implications in designing hybrid heterostructures.Effective organization of small CdSe quantum dots on graphene sheets has been achieved by a simple solution exchange with thiol terminated graphene prepared by diazonium salt chemistry. This generic methodology of CdSe QD attachment to any graphene surface has remarkable implications in designing hybrid heterostructures. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr00363a

How Many Grid Points are Required for Time Accurate Simulations Scheme Selection and Scale-Discriminant Stabilization

DTIC Science & Technology

2015-11-24

spatial concerns: ¤ how well are gradients captured? (resolution requirement) spatial/temporal concerns: ¤ dispersion and dissipation error...distribution is unlimited. Gradient Capture vs. Resolution: Single Mode FFT: Solution/Derivative: Convergence: f x( )= sin(x) with x∈[0,2π ] df dx...distribution is unlimited. Gradient Capture vs. Resolution: 
 Multiple Modes FFT: Solution/Derivative: Convergence: 6 __ CD02 __ CD04 __ CD06

Toxicity of Pb and of Pb/Cd combination on the springtail Folsomia candida in natural soils: reproduction, growth and bioaccumulation as indicators.

PubMed

Bur, T; Crouau, Y; Bianco, A; Gandois, L; Probst, A

2012-01-01

The toxicity of Pb and Cd+Pb was assessed on the Collembola F. candida in two cultivated soils (SV and AU) with low organic matter (OM) content and circumneutral to basic pH, and an acid forested soil (EPC) with high OM content. Collembola reproduction and growth as well as metal content in Collembola body, in soil, exchangeable fraction and soil solutions, pH and DOC were investigated. Pb and Cd+Pb were the highest in exchangeable fraction and soil solution of the acidic soils. Soil solution pH decreased after metal spiking in every soil due to metal adsorption, which was similar for Cd and the highest in AU for Pb. With increasing Pb and Cd+Pb, the most important reproduction decrease was in EPC soil. The LOEC for reproduction after metal addition was 2400 (Pb) and 200/2400 (Cd/Pb), 1200 and 100/1200, 300 and 100/1200 μg g(-1) for AU, SV and EPC, respectively. The highest and the lowest Pb toxicity was observed for EPC and AU bulk soil, respectively. The metal in Collembola increased with increasing soil concentration, except in AU, but the decreasing BF(solution) with increasing concentrations indicates a limited metal transfer to Collembola or an increased metal removal. Loading high Pb concentrations decreases Cd absorption by the Collembola, but the reverse was not true. The highest Pb toxicity in EPC can be explained by pH and OM content. Because of metal complexation, OM might have a protective role but its ingestion by Collembola lead to higher toxicity. Metal bioavailability in Collembola differs from soil solution indicating that soil solution is not sufficient to evaluate toxicity in soil organisms. The toxicity as a whole decreased when metals were combined, except for Pb in AU, due to adsorption competition between Cd and Pb on clay particles and OM sites in AU and EPC soils, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Preparation of alpha sources using magnetohydrodynamic electrodeposition for radionuclide metrology.

PubMed

Panta, Yogendra M; Farmer, Dennis E; Johnson, Paula; Cheney, Marcos A; Qian, Shizhi

2010-02-01

Expanded use of nuclear fuel as an energy resource and terrorist threats to public safety clearly require the development of new state-of-the-art technologies and improvement of safety measures to minimize the exposure of people to radiation and the accidental release of radiation into the environment. The precision in radionuclide metrology is currently limited by the source quality rather than the detector performance. Electrodeposition is a commonly used technique to prepare massless radioactive sources. Unfortunately, the radioactive sources prepared by the conventional electrodeposition method produce poor resolution in alpha spectrometric measurements. Preparing radioactive sources with better resolution and higher yield in the alpha spectrometric range by integrating magnetohydrodynamic convection with the conventional electrodeposition technique was proposed and tested by preparing mixed alpha sources containing uranium isotopes ((238)U, (234)U), plutonium ((239)Pu), and americium ((241)Am) for alpha spectrometric determination. The effects of various parameters such as magnetic flux density, deposition current and time, and pH of the sample solution on the formed massless radioactive sources were also experimentally investigated. Copyright 2009 Elsevier Inc. All rights reserved.

Metrological analysis of the human foot: 3D multisensor exploration

NASA Astrophysics Data System (ADS)

Muñoz Potosi, A.; Meneses Fonseca, J.; León Téllez, J.

2011-08-01

In the podiatry field, many of the foot dysfunctions are mainly generated due to: Congenital malformations, accidents or misuse of footwear. For the treatment or prevention of foot disorders, the podiatrist diagnoses prosthesis or specific adapted footwear, according to the real dimension of foot. Therefore, it is necessary to acquire 3D information of foot with 360 degrees of observation. As alternative solution, it was developed and implemented an optical system of threedimensional reconstruction based in the principle of laser triangulation. The system is constituted by an illumination unit that project a laser plane into the foot surface, an acquisition unit with 4 CCD cameras placed around of axial foot axis, an axial moving unit that displaces the illumination and acquisition units in the axial axis direction and a processing and exploration unit. The exploration software allows the extraction of distances on three-dimensional image, taking into account the topography of foot. The optical system was tested and their metrological performances were evaluated in experimental conditions. The optical system was developed to acquire 3D information in order to design and make more appropriate footwear.

Complex EUV imaging reflectometry: spatially resolved 3D composition determination and dopant profiling with a tabletop 13nm source

NASA Astrophysics Data System (ADS)

Porter, Christina L.; Tanksalvala, Michael; Gerrity, Michael; Miley, Galen P.; Esashi, Yuka; Horiguchi, Naoto; Zhang, Xiaoshi; Bevis, Charles S.; Karl, Robert; Johnsen, Peter; Adams, Daniel E.; Kapteyn, Henry C.; Murnane, Margaret M.

2018-03-01

With increasingly 3D devices becoming the norm, there is a growing need in the semiconductor industry and in materials science for high spatial resolution, non-destructive metrology techniques capable of determining depth-dependent composition information on devices. We present a solution to this problem using ptychographic coherent diffractive imaging (CDI) implemented using a commercially available, tabletop 13 nm source. We present the design, simulations, and preliminary results from our new complex EUV imaging reflectometer, which uses coherent 13 nm light produced by tabletop high harmonic generation. This tool is capable of determining spatially-resolved composition vs. depth profiles for samples by recording ptychographic images at multiple incidence angles. By harnessing phase measurements, we can locally and nondestructively determine quantities such as device and thin film layer thicknesses, surface roughness, interface quality, and dopant concentration profiles. Using this advanced imaging reflectometer, we can quantitatively characterize materials-sciencerelevant and industry-relevant nanostructures for a wide variety of applications, spanning from defect and overlay metrology to the development and optimization of nano-enhanced thermoelectric or spintronic devices.

IMPLICATION OF BIOSOLIDS ON ADSORPTION AND DESORPTION OF CD IN SOILS

EPA Science Inventory

Adsorption isotherms for soils from long-term biosolids-field experiments and their inorganic fractions were obtained by equilibration of the samples with cadmium nitrate. The cadmium nitrate solution was replaced with a calcium nitrate solution to obtain desorbed Cd. Results sho...

Removal of Cd(II) from aqueous solution with activated Firmiana Simplex Leaf: behaviors and affecting factors.

PubMed

Tang, Qiang; Tang, Xiaowu; Hu, Manman; Li, Zhenze; Chen, Yunmin; Lou, Peng

2010-07-15

Cadmium pollution is known to cause severe public health problems. This study is intended to examine the effect of an activated Firmiana Simplex Leaf (FSL) on the removal of Cd(II) from aqueous solution. Results showed that the active Firmiana Simplex Leaf could efficiently remove Cd(II) from wastewater due to the preservation of beneficial groups (amine, carboxyl, and phosphate) at a temperature of 250 degrees C. The adsorbent component, dosage, concentration of the initial solute, and the pH of the solution were all found to have significant effects on Cd(II) adsorption. The kinetic constants were predicted by pseudo-first-order kinetics, and the thermodynamic analysis revealed the endothermic and spontaneous nature of the adsorption. FT-IR and XRD analyses confirmed the strong adsorption between beneficial groups and cadmium ions, and the adsorption capacity was calculated to be 117.786 mg g(-1) according to the Langmuir isotherm. 2010 Elsevier B.V. All rights reserved.

Electronic structure and optical properties of CdSxSe1-x solid solution nanostructures from X-ray absorption near edge structure, X-ray excited optical luminescence, and density functional theory investigations

NASA Astrophysics Data System (ADS)

Murphy, M. W.; Yiu, Y. M.; Ward, M. J.; Liu, L.; Hu, Y.; Zapien, J. A.; Liu, Yingkai; Sham, T. K.

2014-11-01

The electronic structure and optical properties of a series of iso-electronic and iso-structural CdSxSe1-x solid solution nanostructures have been investigated using X-ray absorption near edge structure, extended X-ray absorption fine structure, and X-ray excited optical luminescence at various absorption edges of Cd, S, and Se. It is found that the system exhibits compositions, with variable local structure in-between that of CdS and CdSe accompanied by tunable optical band gap between that of CdS and CdSe. Theoretical calculation using density functional theory has been carried out to elucidate the observations. It is also found that luminescence induced by X-ray excitation shows new optical channels not observed previously with laser excitation. The implications of these observations are discussed.

Cadmium-109 Radioisotope Adsorption onto Polypyrrole Coated Sawdust of Dryobalanops aromatic: Kinetics and Adsorption Isotherms Modelling

PubMed Central

Olatunji, Michael Adekunle; Khandaker, Mayeen Uddin; Amin, Yusoff Mohd; Mahmud, Habibun Nabi Muhammad Ekramul

2016-01-01

A radiotracer study was conducted to investigate the removal characteristics of cadmium (109Cd) from aqueous solution by polypyrrole/ sawdust composite. Several factors such as solution pH, sorbent dosage, initial concentration, contact time, temperature and interfering metal ions were found to have influence on the adsorption process. The kinetics of adsorption was relatively fast, reaching equilibrium within 3 hours. A lowering of the solution pH reduced the removal efficiency from 99.3 to ~ 46.7% and an ambient temperature of 25°C was found to be optimum for maximum adsorption. The presence of sodium and potassium ions inhibited 109Cd removal from its aqueous solution. The experimental data for 109Cd adsorption showed a very good agreement with the Langmuir isotherm and a pseudo-first order kinetic model. The surface condition of the adsorbent before and after cadmium loading was investigated using BET, FESEM and FTIR. Considering the low cost of the precursor’s materials and the toxicity of 109Cd radioactive metal, polypyrrole synthesized on the sawdust of Dryobalanops aromatic could be used as an efficient adsorbent for the removal of 109Cd radioisotope from radionuclide-containing effluents. PMID:27706232

Range-Gated Metrology: An Ultra-Compact Sensor for Dimensional Stabilization

NASA Technical Reports Server (NTRS)

Lay, Oliver P.; Dubovitsky, Serge; Shaddock, Daniel A.; Ware, Brent; Woodruff, Christopher S.

2008-01-01

Point-to-point laser metrology systems can be used to stabilize large structures at the nanometer levels required for precision optical systems. Existing sensors are large and intrusive, however, with optical heads that consist of several optical elements and require multiple optical fiber connections. The use of point-to-point laser metrology has therefore been limited to applications where only a few gauges are needed and there is sufficient space to accommodate them. Range-Gated Metrology is a signal processing technique that preserves nanometer-level or better performance while enabling: (1) a greatly simplified optical head - a single fiber optic collimator - that can be made very compact, and (2) a single optical fiber connection that is readily multiplexed. This combination of features means that it will be straightforward and cost-effective to embed tens or hundreds of compact metrology gauges to stabilize a large structure. In this paper we describe the concept behind Range-Gated Metrology, demonstrate the performance in a laboratory environment, and give examples of how such a sensor system might be deployed.

The Development of a Deflectometer for Accurate Surface Figure Metrology

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail; Eberhardt, Andrew; Ramsey, Brian; Atkins, Carolyn

2015-01-01

Marshall Space Flight Center is developing the method of direct fabrication for high resolution full-shell x-ray optics. In this technique the x-ray optics axial profiles are figured and polished using a computer-controlled ZeekoIRP600X polishing machine. Based on the Chandra optics fabrication history about one third of the manufacturing time is spent on moving a mirror between fabrication and metrology sites, reinstallation and alignment with either the metrology or fabrication instruments. Also, the accuracy of the alignment significantly affects the ultimate accuracy of the resulting mirrors. In order to achieve higher convergence rate it is highly desirable to have a metrology technique capable of in situ surface figure measurements of the optics under fabrication, so the overall fabrication costs would be greatly reduced while removing the surface errors due to the re-alignment necessary after each metrology cycle during the fabrication. The goal of this feasibility study is to demonstrate if the Phase Measuring Deflectometry can be applied for in situ metrology of full shell x-ray optics. Examples of the full-shell mirror substrates suitable for the direct fabrication

The effect of pH and triethanolamine on sulfisoxazole complexation with hydroxypropyl-beta-cyclodextrin.

PubMed

Gladys, Granero; Claudia, Garnero; Marcela, Longhi

2003-11-01

A novel complexation of sulfisoxazole with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was studied. Two systems were used: binary complexes prepared with HP-beta-CD and multicomponent system (HP-beta-CD and the basic compound triethanolamine (TEA)). Inclusion complex formation in aqueous solutions and in solid state were investigated by the solubility method, thermal analysis (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)), Fourier-transform infrared spectroscopy (FT-IR) and dissolution studies. The solid complexes of sulfisoxazole were prepared by freeze-drying the homogeneous concentrated aqueous solutions in molar ratios of sulfisoxazole:HP-beta-CD 1:1 and 1:2, and sulfisoxazole:TEA:HP-beta-CD 1:1:2. FT-IR and thermal analysis showed differences among sulfisoxazole:HP-beta-CD and sulfisoxazole:TEA:HP-beta-CD and their corresponding physical mixtures and individual components. The HP-beta-CD solubilization of sulfisoxazole could be improved by ionization of the drug molecule through pH adjustments. However, larger improvements of the HP-beta-CD solubilization are obtained when multicomponent systems are used, allowing to reduce the amount of CD necessary to prepare the target formulation.

Zn x Cd1-x S tunable band structure-directing photocatalytic activity and selectivity of visible-light reduction of CO2 into liquid solar fuels

NASA Astrophysics Data System (ADS)

Tang, Lanqin; Kuai, Libang; Li, Yichang; Li, Haijin; Zhou, Yong; Zou, Zhigang

2018-02-01

A series of Zn x Cd1-x S monodispersed nanospheres were successfully synthesized with tunable band structures. As-prepared Zn x Cd1-x S solid solutions show much enhanced photocatalytic efficiency for CO2 photoreduction in aqueous solutions under visible light irradiation, relative to pure CdS analog. Methanol (CH3OH) and acetaldehyde (CH3CHO) are the major products of CO2 photoreduction for the solid solutions with x = 0, 0.2, and 0.5. Interestingly, Zn0.8Cd0.2S photocatalyst with a wide band gap can also additionally generate ethanol (CH3CH2OH) besides CH3OH and CH3CHO. The balance between the band structure-directing redox capacity and light absorption should be considered to influence both product yield and selectivity of CO2 photoreduction. The possible photoreduction mechanism was tentatively proposed.

A low-cost iron-cadmium redox flow battery for large-scale energy storage

NASA Astrophysics Data System (ADS)

Zeng, Y. K.; Zhao, T. S.; Zhou, X. L.; Wei, L.; Jiang, H. R.

2016-10-01

The redox flow battery (RFB) is one of the most promising large-scale energy storage technologies that offer a potential solution to the intermittency of renewable sources such as wind and solar. The prerequisite for widespread utilization of RFBs is low capital cost. In this work, an iron-cadmium redox flow battery (Fe/Cd RFB) with a premixed iron and cadmium solution is developed and tested. It is demonstrated that the coulombic efficiency and energy efficiency of the Fe/Cd RFB reach 98.7% and 80.2% at 120 mA cm-2, respectively. The Fe/Cd RFB exhibits stable efficiencies with capacity retention of 99.87% per cycle during the cycle test. Moreover, the Fe/Cd RFB is estimated to have a low capital cost of 108 kWh-1 for 8-h energy storage. Intrinsically low-cost active materials, high cell performance and excellent capacity retention equip the Fe/Cd RFB to be a promising solution for large-scale energy storage systems.

Ultrahigh-efficiency solution-processed simplified small-molecule organic light-emitting diodes using universal host materials

PubMed Central

Han, Tae-Hee; Choi, Mi-Ri; Jeon, Chan-Woo; Kim, Yun-Hi; Kwon, Soon-Ki; Lee, Tae-Woo

2016-01-01

Although solution processing of small-molecule organic light-emitting diodes (OLEDs) has been considered as a promising alternative to standard vacuum deposition requiring high material and processing cost, the devices have suffered from low luminous efficiency and difficulty of multilayer solution processing. Therefore, high efficiency should be achieved in simple-structured small-molecule OLEDs fabricated using a solution process. We report very efficient solution-processed simple-structured small-molecule OLEDs that use novel universal electron-transporting host materials based on tetraphenylsilane with pyridine moieties. These materials have wide band gaps, high triplet energy levels, and good solution processabilities; they provide balanced charge transport in a mixed-host emitting layer. Orange-red (~97.5 cd/A, ~35.5% photons per electron), green (~101.5 cd/A, ~29.0% photons per electron), and white (~74.2 cd/A, ~28.5% photons per electron) phosphorescent OLEDs exhibited the highest recorded electroluminescent efficiencies of solution-processed OLEDs reported to date. We also demonstrate a solution-processed flexible solid-state lighting device as a potential application of our devices. PMID:27819053

Heteroepitaxial growth of cadmium carbonate at dolomite and calcite surfaces: Mechanisms and rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Callagon, Erika Blanca R.; Lee, Sang Soo; Eng, Peter J.

Here, the systematic variation of rates and the mechanism of cadmium uptake on the (104) surface of dolomite (CaMg(CO 3) 2) were investigated using in situ and ex situ atomic force microscopy (AFM), ex situ specular X-ray reflectivity (XR), and ex situ X-ray fluorescence (XRF). Selected experiments were performed on the calcite (CaCO 3) (104) surface for comparison. Aqueous solutions of CdCl 2, CaCl 2, and NaHCO 3, undersaturated with respect to calcite and supersaturated with respect to otavite (CdCO 3) and the (Cd xCa 1-x)CO 3 solid solution, were reacted with dolomite surfaces for minutes to days. Calcite substratesmore » were reacted with solutions containing 1-50 μM CdCl 2, and with no added Ca or CO 3. Thin carbonate films following the Stranski-Krastanov growth mode were observed on both substrates. Specular XR and XRF revealed the formation of nm-thick Cd-rich carbonate films that were structurally ordered with respect to the dolomite (104) plane. Epitaxial films adopted the calcite crystal structure with a d 104- spacing (3.00 Å) larger than those of pure dolomite (2.88 Å) and otavite (2.95 Å) indicating either a solid solution with x approximate to 0.5, or a strained Cd-rich carbonate with a composition near that of otavite. The growth rate r of this phase increases with the initial supersaturation of the solution with respect to the solid solution, beta max, and follows the empirical relationship, as determined from XRF measurements, given by: r = 10 -4.88 ± 0.42 (β 2.29 ± 0.24 max - 1), (in units of atoms of Cd/Å 2/h).The morphology of the overgrowth also varied with β max, as exemplified by AFM observations. Growth at step edges occurred over the entire β max range considered, and additional growth features including 3 Å high monolayer islands and ~ 25 Å high tall islands were observed when log β max > 1. On calcite, in situ XR indicated that this phase is similar to the Cd-rich overgrowth formed on dolomite and images obtained from X-ray reflection interface microscopy (XRIM) reveal the existence of laterally variable Cd-rich domains.« less

Heteroepitaxial growth of cadmium carbonate at dolomite and calcite surfaces: Mechanisms and rates

DOE PAGES

Callagon, Erika Blanca R.; Lee, Sang Soo; Eng, Peter J.; ...

2016-12-10

Here, the systematic variation of rates and the mechanism of cadmium uptake on the (104) surface of dolomite (CaMg(CO 3) 2) were investigated using in situ and ex situ atomic force microscopy (AFM), ex situ specular X-ray reflectivity (XR), and ex situ X-ray fluorescence (XRF). Selected experiments were performed on the calcite (CaCO 3) (104) surface for comparison. Aqueous solutions of CdCl 2, CaCl 2, and NaHCO 3, undersaturated with respect to calcite and supersaturated with respect to otavite (CdCO 3) and the (Cd xCa 1-x)CO 3 solid solution, were reacted with dolomite surfaces for minutes to days. Calcite substratesmore » were reacted with solutions containing 1-50 μM CdCl 2, and with no added Ca or CO 3. Thin carbonate films following the Stranski-Krastanov growth mode were observed on both substrates. Specular XR and XRF revealed the formation of nm-thick Cd-rich carbonate films that were structurally ordered with respect to the dolomite (104) plane. Epitaxial films adopted the calcite crystal structure with a d 104- spacing (3.00 Å) larger than those of pure dolomite (2.88 Å) and otavite (2.95 Å) indicating either a solid solution with x approximate to 0.5, or a strained Cd-rich carbonate with a composition near that of otavite. The growth rate r of this phase increases with the initial supersaturation of the solution with respect to the solid solution, beta max, and follows the empirical relationship, as determined from XRF measurements, given by: r = 10 -4.88 ± 0.42 (β 2.29 ± 0.24 max - 1), (in units of atoms of Cd/Å 2/h).The morphology of the overgrowth also varied with β max, as exemplified by AFM observations. Growth at step edges occurred over the entire β max range considered, and additional growth features including 3 Å high monolayer islands and ~ 25 Å high tall islands were observed when log β max > 1. On calcite, in situ XR indicated that this phase is similar to the Cd-rich overgrowth formed on dolomite and images obtained from X-ray reflection interface microscopy (XRIM) reveal the existence of laterally variable Cd-rich domains.« less

Can ligand addition to soil enhance Cd phytoextraction? A mechanistic model study.

PubMed

Lin, Zhongbing; Schneider, André; Nguyen, Christophe; Sterckeman, Thibault

2014-11-01

Phytoextraction is a potential method for cleaning Cd-polluted soils. Ligand addition to soil is expected to enhance Cd phytoextraction. However, experimental results show that this addition has contradictory effects on plant Cd uptake. A mechanistic model simulating the reaction kinetics (adsorption on solid phase, complexation in solution), transport (convection, diffusion) and root absorption (symplastic, apoplastic) of Cd and its complexes in soil was developed. This was used to calculate plant Cd uptake with and without ligand addition in a great number of combinations of soil, ligand and plant characteristics, varying the parameters within defined domains. Ligand addition generally strongly reduced hydrated Cd (Cd(2+)) concentration in soil solution through Cd complexation. Dissociation of Cd complex ([Formula: see text]) could not compensate for this reduction, which greatly lowered Cd(2+) symplastic uptake by roots. The apoplastic uptake of [Formula: see text] was not sufficient to compensate for the decrease in symplastic uptake. This explained why in the majority of the cases, ligand addition resulted in the reduction of the simulated Cd phytoextraction. A few results showed an enhanced phytoextraction in very particular conditions (strong plant transpiration with high apoplastic Cd uptake capacity), but this enhancement was very limited, making chelant-enhanced phytoextraction poorly efficient for Cd.

Evaluation of organic amendment on the effect of cadmium bioavailability in contaminated soils using the DGT technique and traditional methods.

PubMed

Yao, Yu; Sun, Qin; Wang, Chao; Wang, Pei-Fang; Ding, Shi-Ming

2017-03-01

Organic amendments have been widely proposed as a remediation technology for metal-contaminated soils, but there exist controversial results on their effectiveness. In this study, the effect of pig manure addition on cadmium (Cd) bioavailability in Cd-contaminated soils was systematically evaluated by one dynamic, in situ technique of diffusive gradients in thin films (DGT) and four traditional methods based on the equilibrium theory (soil solution concentration and the three commonly used extractants, i.e., acetic acid (HAc), ethylenediamine tetraacetic acid (EDTA), and calcium chloride (CaCl 2 ). Wheat and maize were selected for measurement of plant Cd uptake. The results showed that pig manure addition could promote the growth of two plants, accompanied by increasing biomasses of shoots and roots with increasing doses of pig manure addition. Correspondingly, increasing additions of pig manure reduced plant Cd uptake and accumulation, as indicated by the decreases of Cd concentrations in shoots and roots. The bioavailable concentrations of Cd in Cd-contaminated soils reflected by the DGT technique obviously decreased with increasing doses of pig manure addition, following the same changing trend as plant Cd uptake. Changes in soil solution Cd concentration and extractable Cd by HAc, EDTA, and CaCl 2 in soils were similar to DGT measurement. Meanwhile, the capability of Cd resupply from solid phase to soil solution decreased with increasing additions of pig manure, as reflected by the decreases in the ratio (R) value of C DGT to C sol . Positive correlations were observed between various bioavailable indicators of Cd in soils and Cd concentrations in the tissues of the two plants. These findings provide stronger evidence that pig manure amendment is effective in reducing Cd mobility and bioavailability in soils and it is an ideal organic material for remediation of Cd-contaminated soils.

Mechanisms of Fe biofortification and mitigation of Cd accumulation in rice (Oryza sativa L.) grown hydroponically with Fe chelate fertilization.

PubMed

Chen, Zhe; Tang, Ye-Tao; Zhou, Can; Xie, Shu-Ting; Xiao, Shi; Baker, Alan J M; Qiu, Rong-Liang

2017-05-01

Cadmium contaminated rice from China has become a global food safety issue. Some research has suggested that chelate addition to substrates can affect metal speciation and plant metal content. We investigated the mitigation of Cd accumulation in hydroponically-grown rice supplied with EDTANa 2 Fe(II) or EDDHAFe(III). A japonica rice variety (Nipponbare) was grown in modified Kimura B solution containing three concentrations (0, 10, 100 μΜ) of the iron chelates EDTANa 2 Fe(II) or EDDHAFe(III) and 1 μΜ Cd. Metal speciation in solution was simulated by Geochem-EZ; growth and photosynthetic efficiency of rice were evaluated, and accumulation of Cd and Fe in plant parts was determined. Net Cd fluxes in the meristematic zone, growth zone, and maturation zone of roots were monitored by a non-invasive micro-test technology. Expression of Fe- and Cd-related genes in Fe-sufficient or Fe-deficient roots and leaves were studied by QRT-PCR. Compared to Fe deficiency, a sufficient or excess supply of Fe chelates significantly enhanced rice growth by elevating photosynthetic efficiency. Both Fe chelates increased the Fe content and decreased the Cd content of rice organs, except for the Cd content of roots treated with excess EDDHAFe(III). Compared to EDDHAFe(III), EDTANa 2 Fe(II) exhibited better mitigation of Cd accumulation in rice by generating the EDTANa 2 Cd complex in solution, decreasing net Cd influx and increasing net Cd efflux in root micro-zones. Application of EDTANa 2 Fe(II) and EDDHAFe(III) also reduced Cd accumulation in rice by inhibiting expression of genes involved in transport of Fe and Cd in the xylem and phloem. The 'win-win' situation of Fe biofortification and Cd mitigation in rice was achieved by application of Fe chelates. Root-to-stem xylem transport of Cd and redistribution of Cd in leaves by phloem transport can be regulated in rice through the use of Fe chelates that influence Fe availability and Fe-related gene expression. Fe fertilization decreased Cd influx and increased Cd efflux in rice roots. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improving contact layer patterning using SEM contour based etch model

NASA Astrophysics Data System (ADS)

Weisbuch, François; Lutich, Andrey; Schatz, Jirka; Hertzsch, Tino; Moll, Hans-Peter

2016-10-01

The patterning of the contact layer is modulated by strong etch effects that are highly dependent on the geometry of the contacts. Such litho-etch biases need to be corrected to ensure a good pattern fidelity. But aggressive designs contain complex shapes that can hardly be compensated with etch bias table and are difficult to characterize with standard CD metrology. In this work we propose to implement a model based etch compensation method able to deal with any contact configuration. With the help of SEM contours, it was possible to get reliable 2D measurements particularly helpful to calibrate the etch model. The selections of calibration structures was optimized in combination with model form to achieve an overall errRMS of 3nm allowing the implementation of the model in production.

Coordinate metrology using scanning probe microscopes

NASA Astrophysics Data System (ADS)

Marinello, F.; Savio, E.; Bariani, P.; Carmignato, S.

2009-08-01

New positioning, probing and measuring strategies in coordinate metrology are needed for the accomplishment of true three-dimensional characterization of microstructures, with uncertainties in the nanometre range. In the present work, the implementation of scanning probe microscopes (SPMs) as systems for coordinate metrology is discussed. A new non-raster measurement approach is proposed, where the probe is moved to sense points along free paths on the sample surface, with no loss of accuracy with respect to traditional raster scanning and scan time reduction. Furthermore, new probes featuring long tips with innovative geometries suitable for coordinate metrology through SPMs are examined and reported.

Surface Wave Metrology for Copper/Low-k Interconnects

NASA Astrophysics Data System (ADS)

Gostein, M.; Maznev, A. A.; Mazurenko, A.; Tower, J.

2005-09-01

We review recent advances in the application of laser-induced surface acoustic wave metrology to issues in copper/low-k interconnect development and manufacturing. We illustrate how the metrology technique can be used to measure copper thickness uniformity on a range of features from solid pads to arrays of lines, focusing on specific processing issues in copper electrochemical deposition (ECD) and chemical-mechanical polishing (CMP). In addition, we review recent developments in surface wave metrology for the characterization of low-k dielectric elastic modulus, including the ability to measure within-wafer uniformity of elastic modulus and to characterize porous, anisotropic films.

Enhanced resolution and accuracy of freeform metrology through Subaperture Stitching Interferometry

NASA Astrophysics Data System (ADS)

Supranowitz, Chris; Maloney, Chris; Murphy, Paul; Dumas, Paul

2017-10-01

Recent advances in polishing and metrology have addressed many of the challenges in the fabrication and metrology of freeform surfaces, and the manufacture of these surfaces is possible today. However, achieving the form and mid-spatial frequency (MSF) specifications that are typical of visible imaging systems remains a challenge. Interferometric metrology for freeform surfaces is thus highly desirable for such applications, but the capability is currently quite limited for freeforms. In this paper, we provide preliminary results that demonstrate accurate, high-resolution measurements of freeform surfaces using prototype software on QED's ASI™ (Aspheric Stitching Interferometer).

A capillary electrophoresis chip for the analysis of print and film photographic developing agents in commercial processing solutions using indirect fluorescence detection.

PubMed

Sirichai, S; de Mello, A J

2001-01-01

The separation and detection of both print and film developing agents (CD-3 and CD-4) in photographic processing solutions using chip-based capillary electrophoresis is presented. For simultaneous detection of both analytes under identical experimental conditions a buffer pH of 11.9 is used to partially ionise the analytes. Detection is made possible by indirect fluorescence, where the ions of the analytes displace the anionic fluorescing buffer ion to create negative peaks. Under optimal conditions, both analytes can be analyzed within 30 s. The limits of detection for CD-3 and CD-4 are 0.17 mM and 0.39 mM, respectively. The applicability of the method for the analysis of seasoned photographic processing developer solutions is also examined.

Foam capacity and stability of Sodium Dodecyl Sulfate (SDS) on the presence of contaminant coffee and Cd ions in solution

NASA Astrophysics Data System (ADS)

Haryanto, B.; Chang, C. H.; Kuo, A. T.; Siswarni, M. Z.; Sinaga, T. M. A.

2018-02-01

In this study, the effect of the coffee colloidal particle and Cd ion contaminant on the foam capacity and stability of sodium dodecyl sulfate (SDS) solution was investigated. The foam was generated by using a foam generator. The foam capacity of SDS was first evaluated at different concentrations. After the foam capacity reaching a constant value, the foam stability was then measured by flowing to a column. The results showed that the presence the coffee colloidal particles or Cd ions in the solution would decrease the foam capacity and stability of SDS. In addition, the decreased foam capacity and stability was more pronounced in the presence of coffee colloidal particles than Cd ions. The colloidal particles may have stronger interaction with SDS and thus reduce the formation of the foam.

Transient and diffusion analysis of HgCdTe

NASA Technical Reports Server (NTRS)

Clayton, J. C.

1982-01-01

Solute redistribution during directional solidification of HgCdTe is addressed. Both one-dimensional and two-dimensional models for solute redistribution are treated and model results compared to experiment. The central problem studied is the cause of radial inhomogeneities found in directionally solidified HgCdTe. A large scale gravity-driven interface instability, termed shape instability, is postulated to be the cause of radial inhomogeneities. Recommendations for future work, along with appropriate computer programs, are included.

Effects of low-molecular-weight organic acids on the acute lethality, accumulation, and enzyme activity of cadmium in Eisenia fetida in a simulated soil solution.

PubMed

Liu, Hai-Long; Wang, Yu-Jun; Xuan, Liang; Dang, Fei; Zhou, Dong-Mei

2017-04-01

In the present study, the effects of low-molecular-weight organic acids (LMWOAs) on the toxicity of cadmium (Cd) to Eisenia fetida were investigated in a simulated soil solution. The LMWOAs protected E. fetida from Cd toxicity, as indicated by the increased median lethal concentration (LC50) values and the increased activity of superoxide dismutase. In addition, Cd concentrations in E. fetida decreased dramatically in the presence of LMWOAs. These results were likely because of the complexation between Cd and LMWOAs, which decreased the bioavailability and consequential toxicity of Cd to E. fetida. Notably, LMWOAs reduced Cd toxicity in decreasing order (ethylenediamine tetraacetic acid [EDTA] > citric acid > oxalic acid > malic acid > acetic acid), which was consistent with the decreasing complexation constants between LMWOAs and Cd. These results advance our understanding of the interactions between Cd and LMWOAs in soil. Environ Toxicol Chem 2017;36:1005-1011. © 2016 SETAC. © 2016 SETAC.

Solution processable RGO-CdZnS composite for solar light responsive photocatalytic degradation of 4-Nitrophenol

NASA Astrophysics Data System (ADS)

Ibrahim, Sk; Chakraborty, Koushik; Pal, Tanusri; Ghosh, Surajit

2017-05-01

We report the one pot single step synthesis and characterization of solution processable reduced graphene oxide (RGO) - cadmium zinc sulfide (CdZnS) nanocomposite materials. The composite was characterized structurally and morphologically by XRD and TEM studies. The reduction of GO in RGO-CdZnS composite, was confirmed by XPS and Raman spectroscopy. The photocatalytic activity of the RGO-CdZnS composite was investigated towards the degradation of 4-Nitrophenol. A notable increase of photocatalytic efficiency of RGO-CdZnS compare to controlled CdZnS was observed. Here RGO plays a crucial role to efficient photo induced charge separation from the CdZnS, and decreases the electron-hole recombination probability and subsequently enhanced the photocatalytic activity of the RGO-CdZnS composite material under simulated solar light irradiation. This work highlights the potential application of RGO-based materials in the field of photocatalytic degradation of organic water pollutant.

Roles of chemical metrology in electronics industry and associated environment in Korea: a tutorial.

PubMed

Kang, Namgoo; Joong Kim, Kyung; Seog Kim, Jin; Hae Lee, Joung

2015-03-01

Chemical metrology is gaining importance in electronics industry that manufactures semiconductors, electronic displays, and microelectronics. Extensive and growing needs from this industry have raised the significance of accurate measurements of the amount of substances and material properties. For the first time, this paper presents information on how chemical metrology is being applied to meet a variety of needs in the aspects of quality control of electronics products and environmental regulations closely associated with electronics industry. For a better understanding of the roles of the chemical metrology within electronics industry, the recent research activities and results in chemical metrology are presented using typical examples in Korea where electronic industry is leading a national economy. Particular attention is paid to the applications of chemical metrology for advancing emerging electronics technology developments. Such examples are a novel technique for the accurate quantification of gas composition at nano-liter levels within a MEMS package, the surface chemical analysis of a semiconductor device. Typical metrological tools are also presented for the development of certified reference materials for fluorinated greenhouse gases and proficiency testing schemes for heavy metals and chlorinated toxic gas in order to cope properly with environmental issues within electronics industry. In addition, a recent technique is presented for the accurate measurement of the destruction and removal efficiency of a typical greenhouse gas scrubber. Copyright © 2014 Elsevier B.V. All rights reserved.

Wet Pretreatment-Induced Modification of Cu(In,Ga)Se2/Cd-Free ZnTiO Buffer Interface.

PubMed

Hwang, Suhwan; Larina, Liudmila; Lee, Hojin; Kim, Suncheul; Choi, Kyoung Soon; Jeon, Cheolho; Ahn, Byung Tae; Shin, Byungha

2018-06-20

We report a novel Cd-free ZnTiO buffer layer deposited by atomic layer deposition for Cu(In,Ga)Se 2 (CIGS) solar cells. Wet pretreatments of the CIGS absorbers with NH 4 OH, H 2 O, and/or aqueous solution of Cd 2+ ions were explored to improve the quality of the CIGS/ZnTiO interface, and their effects on the chemical state of the absorber and the final performance of Cd-free CIGS devices were investigated. X-ray photoelectron spectroscopy (XPS) analysis revealed that the aqueous solution etched away sodium compounds accumulated on the CIGS surface, which was found to be detrimental for solar cell operation. Wet treatment with NH 4 OH solution led to a reduced photocurrent, which was attributed to the thinning (or removal) of an ordered vacancy compound (OVC) layer on the CIGS surface as evidenced by an increased Cu XPS peak intensity after the NH 4 OH treatment. However, the addition of Cd 2+ ions to the NH 4 OH aqueous solution suppressed the etching of the OVC by NH 4 OH, explaining why such a negative effect of NH 4 OH is not present in the conventional chemical bath deposition of CdS. The band alignment at the CIGS/ZnTiO interface was quantified using XPS depth profile measurements. A small cliff-like conduction band offset of -0.11 eV was identified at the interface, which indicates room for further improvement of efficiency of the CIGS/ZnTiO solar cells once the band alignment is altered to a slight spike by inserting a passivation layer with a higher conduction band edge than ZnTiO. Combination of the small cliff conduction band offset at the interface, removal of the Na compound via water, and surface doping by Cd ions allowed the application of ZnTiO buffer to CIGS treated with Cd solutions, exhibiting an efficiency of 80% compared to that of a reference CIGS solar cell treated with the CdS.

Cadmium zinc sulfide by solution growth

DOEpatents

Chen, Wen S.

1992-05-12

A process for depositing thin layers of a II-VI compound cadmium zinc sulfide (CdZnS) by an aqueous solution growth technique with quality suitable for high efficiency photovoltaic or other devices which can benefit from the band edge shift resulting from the inclusion of Zn in the sulfide. A first solution comprising CdCl.sub.2 2.5H.sub.2 O, NH.sub.4 Cl, NH.sub.4 OH and ZnCl.sub.2, and a second solution comprising thiourea ((NH.sub.2).sub.2 CS) are combined and placed in a deposition cell, along with a substrate to form a thin i.e. 10 nm film of CdZnS on the substrate. This process can be sequentially repeated with to achieve deposition of independent multiple layers having different Zn concentrations.

Electrical properties of MIS devices on CdZnTe/HgCdTe

NASA Astrophysics Data System (ADS)

Lee, Tae-Seok; Jeoung, Y. T.; Kim, Hyun Kyu; Kim, Jae Mook; Song, Jinhan; Ann, S. Y.; Lee, Ji Y.; Kim, Young Hun; Kim, Sun-Ung; Park, Mann-Jang; Lee, S. D.; Suh, Sang-Hee

1998-10-01

In this paper, we report the capacitance-voltage (C-V) properties of metal-insulator-semiconductor (MIS) devices on CdTe/HgCdTe by the metalorganic chemical vapor deposition (MOCVD) and CdZnTe/HgCdTe by thermal evaporation. In MOCVD, CdTe layers are directly grown on HgCdTe using the metal organic sources of DMCd and DiPTe. HgCdTe layers are converted to n-type and the carrier concentration, ND is low 1015 cm-3 after Hg-vacancy annealing at 260 degrees Celsius. In thermal evaporation, CdZnTe passivation layers were deposited on HgCdTe surfaces after the surfaces were etched with 0.5 - 2.0% bromine in methanol solution. To investigate the electrical properties of the MIS devices, the C-V measurement is conducted at 80 K and 1 MHz. C-V curve of MIS devices on CdTe/HgCdTe by MOCVD has shown nearly flat band condition and large hysteresis, which is inferred to result from many defects in CdTe layer induced during Hg-vacancy annealing process. A negative flat band voltage (VFB approximately equals -2 V) and a small hysteresis have been observed for MIS devices on CdZnTe/HgCdTe by thermal evaporation. It is inferred that the negative flat band voltage results from residual Te4+ on the surface after etching with bromine in methanol solution.

Metrology for Information Technology

DTIC Science & Technology

1997-05-01

Technology (IT) MEL/ITL Task Group on Metrology for Information Technology (IT) U.S. DEPARTMENT OF COMMERCE Technology Administration National Institute of...NIST management requested a white paper on metrology for information technology (IT). A task group was formed to develop this white paper with...representatives from the Manufacturing Engineering Laboratory (MEL), the Information Technology Laboratory (ITL), and Technology Services (TS). The task

Bioavailable cadmium during the bioremediation of phenanthrene-contaminated soils using the diffusive gradients in thin-film technique.

PubMed

Amezcua-Allieri, M A; Rodríguez-Vázquez, R

2006-03-01

To study the impact of fungal bioremediation of phenanthrene on trace cadmium solid-solution fluxes and solution phase concentration. The bioremediation of phenanthrene in soils was performed using the fungus Penicillium frequentans. Metal behaviour was evaluated by the techniques of diffusive gradient in thin-films (DGT) and filtration. Fluxes of cadmium (Cd) show a significant (P < 0.002) increase after the start of bioremediation, indicating that the bioremediation process itself releases significant amount of Cd into solution from the soil solid-phase. Unlike DGT devices, the solution concentration from filtration shows a clear bimodal distribution. We postulate that the initial action of the fungi is most likely to breakdown the surface of the solid phase to smaller, 'solution-phase' material (<0.45 microm) leading to a peak in Cd concentration in solution. Phenanthrene removal from soils by bioremediation ironically results in the mobilization of another toxic pollutant (Cd). Bioremediation of organic pollutants in contaminated soil will likely lead to large increases in the mobilization of toxic metals, increasing metal bio-uptake and incorporation into the wider food chain. Bioremediation strategies need to account for this behaviour and further research is required both to understand the generality of this behaviour and the operative mechanisms.

On the benefit of high resolution and low aberrations for in-die mask registration metrology

NASA Astrophysics Data System (ADS)

Beyer, Dirk; Seidel, Dirk; Heisig, Sven; Steinert, Steffen; Töpfer, Susanne; Scherübl, Thomas; Hetzler, Jochen

2014-10-01

With the introduction of complex lithography schemes like double and multi - patterning and new design principles like gridded designs with cut masks the requirements for mask to mask overlay have increased dramatically. Still, there are some good news too for the mask industry since more mask are needed and qualified. Although always confronted with throughput demands, latest writing tool developments are able to keep pace with ever increasing pattern placement specs not only for global signatures but for in-die features within the active area. Placement specs less than 3nm (max. 3 Sigma) are expected and needed in all cases in order to keep the mask contribution to the overall overlay budget at an accepted level. The qualification of these masks relies on high precision metrology tools which have to fulfill stringent metrology as well as resolution constrains at the same time. Furthermore, multi-patterning and gridded designs with pinhole type cut masks are drivers for a paradigm shift in registration metrology from classical registration crosses to in-die registration metrology on production features. These requirements result in several challenges for registration metrology tools. The resolution of the system must be sufficiently high to resolve small production features. At the same time tighter repeatability is required. Furthermore, tool induced shift (TIS) limit the accuracy of in-die measurements. This paper discusses and demonstrates the importance of low illumination wavelength together with low aberrations for best contrast imaging for in-die registration metrology. Typical effects like tool induced shift are analyzed and evaluated using the ZEISS PROVE® registration metrology tool. Additionally, we will address performance gains when going to higher resolution. The direct impact on repeatability for small features by registration measurements will be discussed as well.

AGILE integration into APC for high mix logic fab

NASA Astrophysics Data System (ADS)

Gatefait, M.; Lam, A.; Le Gratiet, B.; Mikolajczak, M.; Morin, V.; Chojnowski, N.; Kocsis, Z.; Smith, I.; Decaunes, J.; Ostrovsky, A.; Monget, C.

2015-09-01

For C040 technology and below, photolithographic depth of focus control and dispersion improvement is essential to secure product functionality. Critical 193nm immersion layers present initial focus process windows close to machine control capability. For previous technologies, the standard scanner sensor (Level sensor - LS) was used to map wafer topology and expose the wafer at the right Focus. Such optical embedded metrology, based on light reflection, suffers from reading issues that cannot be neglected anymore. Metrology errors are correlated to inspected product area for which material types and densities change, and so optical properties are not constant. Various optical phenomena occur across the product field during wafer inspection and have an effect on the quality and position of the reflected light. This can result in incorrect heights being recorded and exposures possibly being done out of focus. Focus inaccuracy associated to aggressive process windows on critical layers will directly impact product realization and therefore functionality and yield. ASML has introduced an air gauge sensor to complement the optical level sensor and lead to optimal topology metrology. The use of this new sensor is managed by the AGILE (Air Gauge Improved process LEveling) application. This measurement with no optical dependency will correct for optical inaccuracy of level sensor, and so improve best focus dispersion across the product. Due to the fact that stack complexity is more and more important through process steps flow, optical perturbation of standard Level sensor metrology is increasing and is becoming maximum for metallization layers. For these reasons AGILE feature implementation was first considered for contact and all metal layers. Another key point is that standard metrology will be sensitive to layer and reticle/product density. The gain of Agile will be enhanced for multiple product contribution mask and for complex System on Chip. Into ST context (High mix logic Fab) in term of product and technology portfolio AGILE corrects for up to 120nm of product topography error on process layer with less than 50nm depth of focus Based on tool functionalities delivered by ASML and on high volume manufacturing requirement, AGILE integration is a real challenge. Regarding ST requirements "Automatic AGILE" functionality developed by ASML was not a turnkey solution and a dedicated functionality was needed. A "ST homemade AGILE integration" has been fully developed and implemented within ASML and ST constraints. This paper describes this integration in our Advanced Process Control platform (APC).

Hybrid enabled thin film metrology using XPS and optical

NASA Astrophysics Data System (ADS)

Vaid, Alok; Iddawela, Givantha; Mahendrakar, Sridhar; Lenahan, Michael; Hossain, Mainul; Timoney, Padraig; Bello, Abner F.; Bozdog, Cornel; Pois, Heath; Lee, Wei Ti; Klare, Mark; Kwan, Michael; Kang, Byung Cheol; Isbester, Paul; Sendelbach, Matthew; Yellai, Naren; Dasari, Prasad; Larson, Tom

2016-03-01

Complexity of process steps integration and material systems for next-generation technology nodes is reaching unprecedented levels, the appetite for higher sampling rates is on the rise, while the process window continues to shrink. Current thickness metrology specifications reach as low as 0.1A for total error budget - breathing new life into an old paradigm with lower visibility for past few metrology nodes: accuracy. Furthermore, for advance nodes there is growing demand to measure film thickness and composition on devices/product instead of surrogate planar simpler pads. Here we extend our earlier work in Hybrid Metrology to the combination of X-Ray based reference technologies (high performance) with optical high volume manufacturing (HVM) workhorse metrology (high throughput). Our stated goal is: put more "eyes" on the wafer (higher sampling) and enable move to films on pattern structure (control what matters). Examples of 1X front-end applications are used to setup and validate the benefits.

Evaluation of a novel ultra small target technology supporting on-product overlay measurements

NASA Astrophysics Data System (ADS)

Smilde, Henk-Jan H.; den Boef, Arie; Kubis, Michael; Jak, Martin; van Schijndel, Mark; Fuchs, Andreas; van der Schaar, Maurits; Meyer, Steffen; Morgan, Stephen; Wu, Jon; Tsai, Vincent; Wang, Cathy; Bhattacharyya, Kaustuve; Chen, Kai-Hsiung; Huang, Guo-Tsai; Ke, Chih-Ming; Huang, Jacky

2012-03-01

Reducing the size of metrology targets is essential for in-die overlay metrology in advanced semiconductor manufacturing. In this paper, μ-diffraction-based overlay (μDBO) measurements with a YieldStar metrology tool are presented for target-sizes down to 10 × 10 μm2. The μDBO technology enables selection of only the diffraction efficiency information from the grating by efficiently separating it from product structure reflections. Therefore, μDBO targets -even when located adjacent to product environment- give excellent correlation with 40 × 160 μm2 reference targets. Although significantly smaller than standard scribe-line targets, they can achieve total-measurement-uncertainty values of below 0.5 nm on a wide range of product layers. This shows that the new μDBO technique allows for accurate metrology on ultra small in-die targets, while retaining the excellent TMU performance of diffraction-based overlay metrology.

Final Report on the Key Comparison CCM.P-K4.2012 in Absolute Pressure from 1 Pa to 10 kPa

PubMed Central

Ricker, Jacob; Hendricks, Jay; Bock, Thomas; Dominik, Pražák; Kobata, Tokihiko; Torres, Jorge; Sadkovskaya, Irina

2017-01-01

The report summarizes the Consultative Committee for Mass (CCM) key comparison CCM.P-K4.2012 for absolute pressure spanning the range of 1 Pa to 10 000 Pa. The comparison was carried out at six National Metrology Institutes (NMIs), including National Institute of Standards and Technology (NIST), Physikalisch-Technische Bundesanstalt (PTB), Czech Metrology Institute (CMI), National Metrology Institute of Japan (NMIJ), Centro Nacional de Metrología (CENAM), and DI Mendeleyev Institute for Metrology (VNIIM). The comparison was made via a calibrated transfer standard measured at each of the NMIs facilities using their laboratory standard during the period May 2012 to September 2013. The transfer package constructed for this comparison preformed as designed and provided a stable artifact to compare laboratory standards. Overall the participants were found to be statistically equivalent to the key comparison reference value. PMID:28216793

Cd immobilization and reduced tissue Cd accumulation of rice (Oryza sativa wuyun-23) in the presence of heavy metal-resistant bacteria.

PubMed

Li, Ya; Pang, Hai-Dong; He, Lin-Yan; Wang, Qi; Sheng, Xia-Fang

2017-04-01

Two metal-resistant Bacillus megaterium H3 and Neorhizobium huautlense T1-17 were investigated for their immobilization of Cd in solution and tissue Cd accumulation of rice (Oryza sativa wuyun-23) in the Cd-contaminated soil. Strains H3 and T1-17 decreased 79-96% of water-soluble Cd in solution and increased grain biomass in the high Cd-contaminated soil. Inoculation with H3 and T1-17 significantly decreased the root (ranging from 25% to 58%), above-ground tissue (ranging from 13% to 34%), and polished rice (ranging from 45% to 72%) Cd contents as well as Cd bioconcentration factor of the rice compared to the controls. Furthermore, H3 and T1-17 significantly reduced the exchangeable Cd content of the rhizosphere soils compared with the controls. Notably, strain T1-17 had significantly higher ability to reduce Cd bioconcentration factor and polished rice Cd uptake than strain H3. The results demonstrated that H3 and T1-17 decreased the tissue (especially polished rice) Cd uptake by decreasing Cd availability in soil and Cd bioconcentration factor and the effect on the reduced polished rice Cd uptake was dependent on the strains. The results may provide an effective synergistic bioremediation of Cd-contaminated soils in the bacteria and rice plants and bacterial-assisted safe production of rice in Cd-contaminated soils. Copyright © 2016 Elsevier Inc. All rights reserved.

Mechanistic insights from DGT and soil solution measurements on the uptake of Ni and Cd by radish.

PubMed

Luo, Jun; Cheng, Hao; Ren, Jinghua; Davison, William; Zhang, Hao

2014-07-01

This work tests the previously proposed hypothesis that plant uptake of metals is determined dominantly by diffusional controlled or plant limiting uptake mechanisms at, respectively, low and high metal concentrations. Radish (Raphanus sativus) was grown in 13 soils spiked with Ni (10 and 100 mg kg(-1)) and Cd (0.5 and 4 mg kg(-1)) for 4 weeks to investigate the mechanisms affecting plant uptake. Soil solution concentrations, Css, of Ni and Cd were measured, along with the DGT interfacial concentration, CDGT, and the derived effective concentration in soil solution, CE. Free ion activities, aNi(2+) and aCd(2+), were obtained using WHAM 6. Although there was a poor relationship between Ni in radish roots and either Css or aNi(2+) in unamended soils, the distribution of data could be rationalized in terms of the extent of release of Ni from the soil solid phase, as identified by DGT and soil solution measurements. By contrast Ni in radish was linearly related to CE, demonstrating diffusion limited uptake. For soils amended with high concentrations of Ni, linear relationships were obtained for Ni in radish plotted against, Css, aNi(2+), and CE, consistent with the plant controlling uptake. For Ni the hypothesis concerning dominant diffusional and plant limiting uptake mechanisms was demonstrated. Poor relationships between Cd in radish and Css, aCd(2+), and CE, irrespective of amendment by Cd, showed the importance of factors other than diffusional supply, such as rhizosphere and inhibitory processes, and that fulfilment of this hypothesis is plant and metal specific.

Immobilization of CdS nanoparticles formed in reverse micelles onto aluminosilicate supports and their photocatalytic properties.

PubMed

Hirai, Takayuki; Bando, Yoko

2005-08-15

CdS nanoparticles, prepared in reverse micellar system, were immobilized onto thiol-modified aluminosilicate particles (ASSH) by a simple operation: addition of ASSH in the micellar solution and mild stirring. The resulting CdS nanoparticles-aluminosilicate composites (ASCdS) were used as photocatalysts for H2 generation from 2-propanol aqueous solution. The chemical properties of the aluminosilicate, such as affinity for water and other reactants, were found to affect the photocatalytic property of the CdS nanoparticles immobilized. Zeolite particles, having affinity for water and 2-propanol, gave a good ASCdS photocatalyst with respect to H2 generation.

Sorption mechanism of Cd(II) from water solution onto chicken eggshell

NASA Astrophysics Data System (ADS)

Flores-Cano, Jose Valente; Leyva-Ramos, Roberto; Mendoza-Barron, Jovita; Guerrero-Coronado, Rosa María; Aragón-Piña, Antonio; Labrada-Delgado, Gladis Judith

2013-07-01

The mechanism and capacity of eggshell for sorbing Cd(II) from aqueous solution was examined in detail. The eggshell was characterized by several techniques. The eggshell was mainly composed of Calcite (CaCO3). The surface charge distribution was determined by acid-base titration and the point of zero charge (PZC) of the eggshell was found to be 11.4. The sorption equilibrium data were obtained in a batch adsorber, and the adsorption isotherm of Langmuir fitted the data quite well. The sorption capacity of eggshell increased while raising the pH from 4 to 6, this tendency was attributed to the electrostatic interaction between the Cd2+ in solution and the surface of the eggshell. Furthermore, the sorption capacity was augmented by increasing the temperature from 15 to 35 °C because the sorption was endothermic. The sorption of Cd(II) occurred mainly onto the calcareous layer of the eggshell, but slightly on the membrane layer. It was demonstrated that the sorption of Cd(II) was not reversible, and the main sorption mechanisms were precipitation and ion exchange. The precipitation of (Cd,Ca)CO3 on the surface of the eggshell was corroborated by SEM and XRD analysis.

EDITORIAL: Nanometrology Nanometrology

NASA Astrophysics Data System (ADS)

Tanaka, Mitsuru; Baba, Tetsuya; Postek, Michael T.

2011-02-01

Nanomanufacturing is an essential bridge between the discoveries of nanoscience and real-world nanotech products and is the vehicle by which the world will realize the promise of major technological innovation across a spectrum of products that will affect virtually every industrial sector. For micro and nanotech products to achieve the broad impacts envisioned, they must be manufactured in market-appropriate quantities in a reliable, repeatable, economical and commercially viable manner. In addition, they must be manufactured so that environmental and human health concerns are met, worker safety issues are appropriately assessed and handled, and liability issues are addressed. Critical to this realization of robust manufacturing at the nanoscale is the development of the necessary instrumentation, metrology and standards, i.e. nanometrology. The National Measurement Laboratories are committed to developing the required metrology. Integration of the instruments, their interoperability and appropriate information management are also critical elements that must be considered for viable micro and nanomanufacturing. Advanced instrumentation, metrology and standards will allow the physical dimensions, properties, functionality and purity of the materials, processes, tools, systems, products and emissions that will constitute micro and nanomanufacturing to be measured and characterized. This will in turn enable production to be scalable, controllable, predictable and repeatable to meet market needs. If a product cannot be measured it cannot be manufactured; if that product cannot be made safely it should not be manufactured, and finally, if the metrology is not in place how would you know? The articles in this special feature can be classified into three categories: dimensional metrology (8 papers and one technical design note), density of particles (2 papers) and metrology of thermal properties (3 papers). The articles on dimensional metrology include scanning probe microscope dimensional metrology, the through focus scanning optical (TSOM) imaging method, scatterfield optical microscopy, helium ion microscopy, metrology and combinations of these microscopy and imaging techniques applied to nanostructures and particles such as cellulose nanocrystals, and targeted liposome-based delivery systems. Dimensional metrology covers grating pitch measurement by optical diffraction, measurement of the thickness of silicon oxide by synchrotron radiation x-ray photoelectron spectroscopy (SR-XPS) analysis and determination of pore size distribution of porous low-dielectric-constant films by x-ray scattering. The two papers on particle density present number concentration standards for aerosol nanoparticles of larger diameter than about 10 nm and liquid-borne particles in the range of 10-20 µm diameter, respectively. The three papers on metrology of thermal properties present recent innovative progress in thermophysical metrology of thin films by the ultrafast laser flash methods required for understanding of the thermal science at nanoscales and thermal design of nanodevices. The first paper improves the technology applicable under high pressures in a diamond anvil cell. The second extends this technology to thin films on silicon substrates. The third reports the first observation of non-diffusive heat transfer across thin films at low temperatures. In order to guarantee reliability and traceability of developed measurement methods for nanomaterials, a technical infrastructure for nanomaterials such as metrological standards, reference materials and document standards for measurement methods is important. We hope this special feature will be the first step in a collaboration towards a global harmonization of nanometrology.

Lateral Tip Control Effects in CD-AFM Metrology: The Large Tip Limit.

PubMed

Dixson, Ronald G; Orji, Ndubuisi G; Goldband, Ryan S

2016-01-25

Sidewall sensing in critical dimension atomic force microscopes (CD-AFMs) usually involves continuous lateral dithering of the tip or the use of a control algorithm and fast response piezo actuator to position the tip in a manner that resembles touch-triggering of coordinate measuring machine (CMM) probes. All methods of tip position control, however, induce an effective tip width that may deviate from the actual geometrical tip width. Understanding the influence and dependence of the effective tip width on the dither settings and lateral stiffness of the tip can improve the measurement accuracy and uncertainty estimation for CD-AFM measurements. Since CD-AFM typically uses tips that range from 15 nm to 850 nm in geometrical width, the behavior of effective tip width throughout this range should be understood. The National Institute of Standards and Technology (NIST) has been investigating the dependence of effective tip width on the dither settings and lateral stiffness of the tip, as well as the possibility of material effects due to sample composition. For tip widths of 130 nm and lower, which also have lower lateral stiffness, the response of the effective tip width to lateral dither is greater than for larger tips. However, we have concluded that these effects will not generally result in a residual bias, provided that the tip calibration and sample measurement are performed under the same conditions. To validate that our prior conclusions about the dependence of effective tip width on lateral stiffness are valid for large CD-tips, we recently performed experiments using a very large non-CD tip with an etched plateau of approximately 2 μm width. The effective lateral stiffness of these tips is at least 20 times greater than typical CD-AFM tips, and these results supported our prior conclusions about the expected behavior for larger tips. The bottom-line importance of these latest observations is that we can now reasonably conclude that a dither slope of 3 nm/V is the baseline response due to the induced motion of the cantilever base.

Lateral Tip Control Effects in CD-AFM Metrology: The Large Tip Limit

PubMed Central

Dixson, Ronald G.; Orji, Ndubuisi G.; Goldband, Ryan S.

2016-01-01

Sidewall sensing in critical dimension atomic force microscopes (CD-AFMs) usually involves continuous lateral dithering of the tip or the use of a control algorithm and fast response piezo actuator to position the tip in a manner that resembles touch-triggering of coordinate measuring machine (CMM) probes. All methods of tip position control, however, induce an effective tip width that may deviate from the actual geometrical tip width. Understanding the influence and dependence of the effective tip width on the dither settings and lateral stiffness of the tip can improve the measurement accuracy and uncertainty estimation for CD-AFM measurements. Since CD-AFM typically uses tips that range from 15 nm to 850 nm in geometrical width, the behavior of effective tip width throughout this range should be understood. The National Institute of Standards and Technology (NIST) has been investigating the dependence of effective tip width on the dither settings and lateral stiffness of the tip, as well as the possibility of material effects due to sample composition. For tip widths of 130 nm and lower, which also have lower lateral stiffness, the response of the effective tip width to lateral dither is greater than for larger tips. However, we have concluded that these effects will not generally result in a residual bias, provided that the tip calibration and sample measurement are performed under the same conditions. To validate that our prior conclusions about the dependence of effective tip width on lateral stiffness are valid for large CD-tips, we recently performed experiments using a very large non-CD tip with an etched plateau of approximately 2 μm width. The effective lateral stiffness of these tips is at least 20 times greater than typical CD-AFM tips, and these results supported our prior conclusions about the expected behavior for larger tips. The bottom-line importance of these latest observations is that we can now reasonably conclude that a dither slope of 3 nm/V is the baseline response due to the induced motion of the cantilever base. PMID:27087883

Manufacturing Laboratory for Next Generation Engineers

DTIC Science & Technology

2013-12-16

automated CNC machines, rapid prototype systems, robotic assembly systems, metrology , and non-traditional systems such as a waterjet cutter, EDM machine...CNC machines, rapid prototype systems, robotic assembly systems, metrology , and non-traditional systems such as a waterjet cutter, EDM machine, plasma...System Metrology and Quality Control Equipment - This area already had a CMM and other well known quality control instrumentation. It has been enhanced

Emerging technology for astronomical optics metrology

NASA Astrophysics Data System (ADS)

Trumper, Isaac; Jannuzi, Buell T.; Kim, Dae Wook

2018-05-01

Next generation astronomical optics will enable science discoveries across all fields and impact the way we perceive the Universe in which we live. To build these systems, optical metrology tools have been developed that push the boundary of what is possible. We present a summary of a few key metrology technologies that we believe are critical for the coming generation of optical surfaces.

IT Security Standards and Legal Metrology - Transfer and Validation

NASA Astrophysics Data System (ADS)

Thiel, F.; Hartmann, V.; Grottker, U.; Richter, D.

2014-08-01

Legal Metrology's requirements can be transferred into the IT security domain applying a generic set of standardized rules provided by the Common Criteria (ISO/IEC 15408). We will outline the transfer and cross validation of such an approach. As an example serves the integration of Legal Metrology's requirements into a recently developed Common Criteria based Protection Profile for a Smart Meter Gateway designed under the leadership of the Germany's Federal Office for Information Security. The requirements on utility meters laid down in the Measuring Instruments Directive (MID) are incorporated. A verification approach to check for meeting Legal Metrology's requirements by their interpretation through Common Criteria's generic requirements is also presented.

A metrological approach to improve accuracy and reliability of ammonia measurements in ambient air

NASA Astrophysics Data System (ADS)

Pogány, Andrea; Balslev-Harder, David; Braban, Christine F.; Cassidy, Nathan; Ebert, Volker; Ferracci, Valerio; Hieta, Tuomas; Leuenberger, Daiana; Martin, Nicholas A.; Pascale, Céline; Peltola, Jari; Persijn, Stefan; Tiebe, Carlo; Twigg, Marsailidh M.; Vaittinen, Olavi; van Wijk, Janneke; Wirtz, Klaus; Niederhauser, Bernhard

2016-11-01

The environmental impacts of ammonia (NH3) in ambient air have become more evident in the recent decades, leading to intensifying research in this field. A number of novel analytical techniques and monitoring instruments have been developed, and the quality and availability of reference gas mixtures used for the calibration of measuring instruments has also increased significantly. However, recent inter-comparison measurements show significant discrepancies, indicating that the majority of the newly developed devices and reference materials require further thorough validation. There is a clear need for more intensive metrological research focusing on quality assurance, intercomparability and validations. MetNH3 (Metrology for ammonia in ambient air) is a three-year project within the framework of the European Metrology Research Programme (EMRP), which aims to bring metrological traceability to ambient ammonia measurements in the 0.5-500 nmol mol-1 amount fraction range. This is addressed by working in three areas: (1) improving accuracy and stability of static and dynamic reference gas mixtures, (2) developing an optical transfer standard and (3) establishing the link between high-accuracy metrological standards and field measurements. In this article we describe the concept, aims and first results of the project.

Forensic Metrology: Its Importance and Evolution in the United States

NASA Astrophysics Data System (ADS)

Vosk, JD Ted

2016-11-01

Forensic measurements play a significant role in the U.S. criminal justice system. Guilt or innocence, or the severity of a sentence, may depend upon the results of such measurements. Until recently, however, forensic disciplines were largely unaware of the field of metrology. Accordingly, proper measurement practices were often, and widely, neglected. These include failure to adopt proper calibration techniques, establish the traceability of results and determine measurement uncertainty. These failures undermine confidence in verdicts based upon forensic measurements. Over the past decade, though, the forensic sciences have been introduced to metrology and its principles leading to more reliable measurement practices. The impetus for this change was driven by many forces. Pressure came initially from criminal defense lawyers challenging metrologically unsound practices and results relied upon by government prosecutions. Litigation in the State of Washington led this movement spurring action by attorneys in other jurisdictions and eventually reform in the measurement practices of forensic labs around the country. Since then, the greater scientific community, other forensic scientists and even prosecutors have joined the fight. This paper describes the fight to improve the quality of justice by the application of metrological principles and the evolution of the field of forensic metrology.

Self-mixing interferometry: a novel yardstick for mechanical metrology

NASA Astrophysics Data System (ADS)

Donati, Silvano

2016-11-01

A novel configuration of interferometry, SMI (self-mixing interferometry), is described in this paper. SMI is attractive because it doesn't require any optical part external to the laser and can be employed in a variety of measurements - indeed it is sometimes indicated as the "interferometer for measuring without an interferometer". On processing the phase carried by the optical field upon propagation to the target under test, a number of applications have been developed, including traditional measurements related to metrology and mechanical engineering - like displacement, distance, small-amplitude vibrations, attitude angles, velocity, as well as new measurements, like mechanical stress-strain hysterisis and microstructure/MEMS electro-mechanical response. In another field, sensing of motility finds direct application in a variety of biophysical measurements, like blood pulsation, respiratory sounds, chest acoustical impedance, and blood velocity profile. And, we may also look at the amplitude of the returning signal in a SMI, and we can measure weak optical echoes - for return loss and isolation factor measurements, CD readout and scroll sensing, and THz-wave detection. Last, the fine details of the SMI waveform reveal physical parameters of the laser like the laser linewidth, coherence length, and alpha factor. Worth to be noted, SMI is also a coherent detection scheme, and measurement close to the quantum limit of received field with minimum detectable displacements of 100 pm/√Hz are currently achieved upon operation on diffusive targets, whereas in detection mode returning signal can be sensed down to attenuations of -80dB.

Removal of Cd (II) from water using the waste of jatropha fruit ( Jatropha curcas L.)

NASA Astrophysics Data System (ADS)

Nacke, Herbert; Gonçalves, Affonso Celso; Coelho, Gustavo Ferreira; Schwantes, Daniel; Campagnolo, Marcelo Angelo; Leismann, Eduardo Ariel Völz; Junior, Élio Conradi; Miola, Alisson Junior

2017-10-01

The aim of this work was to evaluate the removal of Cd (II) from water using three biosorbents originated from the biomass of jatropha (bark, endosperm, and endosperm + tegument). For that, batch tests were performed to verify the effect of solution pH, adsorbent mass, contact time, initial concentration of Cd (II), and the temperature of the process. The adsorption process was evaluated by the studies of kinetics, isotherms, and thermodynamics. The ideal conditions of solution pH were 5.5 and 8 g L-1 of adsorbent mass of biosorbents by solution volume, with an equilibrium time of 60 min. According to the Langmuir model, the maximum adsorption capacity for bark, endosperm, and bark + endosperm of jatropha was, respectively, 29.665, 19.562, and 34.674 mg g-1, predominating chemisorption in monolayers. The biosorbents presented potential for the remediation of waters contaminated with Cd (II).

Removal of lead and cadmium from aqueous solutions by using 4-amino-3-hydroxynaphthalene sulfonic acid-doped polypyrrole films.

PubMed

Sall, Mohamed Lamine; Diaw, Abdou Karim Diagne; Gningue-Sall, Diariatou; Chevillot-Biraud, Alexandre; Oturan, Nihal; Oturan, Mehmet Ali; Fourdrin, Chloé; Huguenot, David; Aaron, Jean-Jacques

2018-03-01

Water pollution by heavy metals is a great health concern worldwide. Lead and cadmium are among the most toxic heavy metals because they are dangerous for the human and aquatic lives. In this work, the removal of lead and cadmium from aqueous solutions has been studied using electrosynthesized 4-amino-3-hydroxynaphthalene-1-sulfonic acid-doped polypyrrole (AHNSA-PPy) films as a new adsorbent. Two distinct methods, including the immersion method, based on the Pb 2+ and Cd 2+ spontaneous removal by impregnation of the polymer in the solution, and the electro-elimination method, consisting of removal of Pb 2+ and Cd 2+ ions from the solution by applying a small electrical current (5 mA) to the polymer film, were developed: the evolution of Pb 2+ and Cd 2+ concentrations with time was monitored by inductively coupled plasma optical emission spectrometry (ICP-OES). The effect of pH on the adsorption and electro-elimination of Pb 2+ and Cd 2+ using the AHNSA-PPy film was investigated and optimized, showing that the ionic adsorption and electro-elimination processes were highly pH-dependent. The kinetics of Pb 2+ and Cd 2+ adsorption and electro-elimination were found to follow second-order curves. The maximum adsorption capacity values of the AHNSA-PPy film were 64.0 and 50.4 mg/g, respectively, for Pb 2+ and Cd 2+ . The removal efficiency values were, respectively, for Pb 2+ and Cd 2+ , 80 and 63% by the immersion method, and 93 and 85% by the electro-elimination method. Application of both methods to Senegal natural waters, fortified with Pb 2+ and Cd 2+ , led to removal efficiency values of, respectively for Pb 2+ and Cd 2+ , 76-77 and 58-59% by the immersion method, and of 82-90 and 80-83%, by the electro-elimination method.

Coprecipitation mechanisms and products in manganese oxidation in the presence of cadmium

USGS Publications Warehouse

Hem, J.D.; Lind, Carol J.

1991-01-01

Manganese oxidation products were precipitated in an aerated open-aqueous system where a continuous influx of mixed Mn2+ and Cd2+ solution was supplied and pH was maintained with an automated pH-stat adding dilute NaOH. X-ray diffraction and electron diffraction identified the solids produced as mixtures of Cd2Mn34+O8, Mn2+2Mn4+3O8, MnO2 (ramsdellite), and CdCO3. Mean oxidation numbers of the total precipitated Mn as great as 3.6 were reached during titrations. During subsequent aging in solution, oxidation numbers between 3.8 and 3.9 were reached in some precipitates in less than 40 days. Conditional oxidation rate constants calculated from a crystal-growth equation applied to titration data showed the overall precipitation rate, without considering manganese oxidation state in the precipitate, was increased by a factor of ~4 to ~7 when the mole ratio (Cd/Mn + Cd) of cadmium in the feed solution was 0.40 compared with rate constants for hausmannite (Mn2+Mn23+O4 precipitation under similar conditions but without accessory metals. Kinetic experiments were made to test effects of various Cd/Mn + Cd mole ratios and rates of addition of the feed solution, different temperatures from 5.0 to 35??C, and pH from 8.0 to 9.0. Oxidation rates were slower when the Cd mole ratio was less than 0.40. The rate increased by a factor of ~10 when pH was raised one-half unit. The effect of temperature on the rate constants was also substantial, but the meaning of this is uncertain because the rate of formation of Mn4+ oxide in the absence of Cd or other accessory metals was too slow to be measurable in titration experiments. The increased rate of Mn4+ oxide formation in the presence of Cd2+ can be ascribed to the formation of a labile adsorbed intermediate, CdMn2O4 Int, an analog of hausmannite, formed on precipitate surfaces at the beginning of the oxidation process. The increased lability of this structure, resulting from coordination-chemical behavior of Cd2+ during the titration, causes a rapid second-stage rearrangement and facilitates disproportionation of the Mn3+ ions. The Mn2+ ions thus released provide a positive feedback mechanism that couples the two steps of the conversion of Mn2+ to Mn4+ more closely than is possible when other metal ions besides manganese are not present. During aging of precipitates in contact with solutions, proportions of Cd2Mn3O8 and MnO2 increased at the expense of other precipitate components. ?? 1991.

SECONDARY DEUTERIUM ISOTOPE EFFECTS IN SOME SN1 AND E$sub 2$ REACTIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asperger, S.; Illakovac, N.; Pavlovic, D.

1962-01-01

The reaction rate of 0.025 M solution of PhCH/sub 2/CD/sub 2/Br(I) with NaOEt (0.019 M) in anh. EtOH was measured at 59.8 deg C by extinction at 248 m mu . A k/sub H//k/sub D/ value of 1.17 was found. k/sub H//k/sub D/ = 1 was measured potentiometrically for the reaction of 0.05 M solutions of PhCH/sub 2/CD/ sub a/SMe/sub 2/Br(II) and NaOH in H/sub 2/O at 79.55 deg C. With II, about 75% D exchanged during reaction in 2 to 5 M solutions k/sub H//k/sub D/ = 1.25 was determined potentiometrically for the hydrolysis of MeCD/sub 2/C(CD/sub 3/)/sub 2/more » SMe/sub 2 /I (0.05 M solution) at 59.75 deg C. The smaller isotope effects in reactions of sulfonium salts vs halides are explained by larger electron transfer in the transition state of the latter reactions. k/sub H//k/sub D/> 1 in the E/ sub 2/ reaction of I is ascribed to partial rehybridization of C-D bonds in the rate-determining step. (auth)« less

Poly(methacrylic acid)-grafted chitosan microspheres via surface-initiated ATRP for enhanced removal of Cd(II) ions from aqueous solution.

PubMed

Huang, Liqiang; Yuan, Shaojun; Lv, Li; Tan, Guangqun; Liang, Bin; Pehkonen, S O

2013-09-01

Cross-linked chitosan (CCS) microspheres tethered with pH-sensitive poly(methacrylic acid) (PMAA) brushes were developed for the efficient removal of Cd(II) ions from aqueous solutions. Functional PMAA brushes containing dense and active carboxyl groups (COOH) were grafted onto the CCS microsphere surface via surface-initiated atom transfer radical polymerization (ATRP). Batch adsorption results showed that solution pH values had a major impact on cadmium adsorption by the PMAA-grafted CCS microspheres with the optimal removal observed above pH 5. The CCS-g-PMAA microsphere was found to achieve the adsorption equilibrium of Cd(II) within 1 h, much faster than about 7 h on the CCS microsphere. At pH 5 and with an initial concentration 0.089-2.49 mmol dm(-3), the maximum adsorption capacity of Cd(II), derived from the Langmuir fitting on the PMAA-grafted microspheres was around 1.3 mmol g(-1). Desorption and adsorption cycle experimental results revealed that the PMAA-grafted CCS microspheres loaded with Cd(II) can be effectively regenerated in a dilute HNO3 solution, and the adsorption capacity remained almost unchanged upon five cycle reuse. Copyright © 2013 Elsevier Inc. All rights reserved.

PREFACE: 3rd International Congress on Mechanical Metrology (CIMMEC2014)

NASA Astrophysics Data System (ADS)

2015-10-01

From October 14th to 16th 2014, The Brazilian National Institute of Metrology, Quality, and Technology (Inmetro) and the Brazilian Society of Metrology (SBM) organized the 3rd International Congress on Mechanical Metrology (3rd CIMMEC). The 3rd CIMMEC was held in the city of Gramado, Rio Grande do Sul, Brazil. Anticipating the interest and enthusiasm of the technical-scientific community, the Organizing Institutions invite people and organizations to participate in this important congress, reiterating the commitment to organize an event according to highest international standards. This event has been conceived to integrate people and organizations from Brazil and abroad in the discussion of advanced themes in metrology. Manufacturers and dealers of measuring equipment and standards, as well as of auxiliary accessories and bibliographic material, had the chance to promote their products and services in stands at the Fair, which has taken place alongside the Congress. The 3rd CIMMEC consisted of five Keynote Speeches and 116 regular papers. Among the regular papers, the 25 most outstanding ones, comprising a high quality content on Mechanical Metrology, were selected to be published in this issue of Journal of Physics: Conference Series. It is our great pleasure to present this volume of Journal of Physics: Conference Series to the scientific community to promote further research in Mechanical Metrology and related areas. We believe that this volume will be both an excellent source of scientific material in the fast evolving fields that were covered by CIMMEC 2014.

Implementation and performance of the metrology system for the multi-object optical and near-infrared spectrograph MOONS

NASA Astrophysics Data System (ADS)

Drass, Holger; Vanzi, Leonardo; Torres-Torriti, Miguel; Dünner, Rolando; Shen, Tzu-Chiang; Belmar, Francisco; Dauvin, Lousie; Staig, Tomás.; Antognini, Jonathan; Flores, Mauricio; Luco, Yerko; Béchet, Clémentine; Boettger, David; Beard, Steven; Montgomery, David; Watson, Stephen; Cabral, Alexandre; Hayati, Mahmoud; Abreu, Manuel; Rees, Phil; Cirasuolo, Michele; Taylor, William; Fairley, Alasdair

2016-08-01

The Multi-Object Optical and Near-infrared Spectrograph (MOONS) will cover the Very Large Telescope's (VLT) field of view with 1000 fibres. The fibres will be mounted on fibre positioning units (FPU) implemented as two-DOF robot arms to ensure a homogeneous coverage of the 500 square arcmin field of view. To accurately and fast determine the position of the 1000 fibres a metrology system has been designed. This paper presents the hardware and software design and performance of the metrology system. The metrology system is based on the analysis of images taken by a circular array of 12 cameras located close to the VLTs derotator ring around the Nasmyth focus. The system includes 24 individually adjustable lamps. The fibre positions are measured through dedicated metrology targets mounted on top of the FPUs and fiducial markers connected to the FPU support plate which are imaged at the same time. A flexible pipeline based on VLT standards is used to process the images. The position accuracy was determined to 5 μm in the central region of the images. Including the outer regions the overall positioning accuracy is 25 μm. The MOONS metrology system is fully set up with a working prototype. The results in parts of the images are already excellent. By using upcoming hardware and improving the calibration it is expected to fulfil the accuracy requirement over the complete field of view for all metrology cameras.

The Wronskian solution of the constrained discrete Kadomtsev-Petviashvili hierarchy

NASA Astrophysics Data System (ADS)

Li, Maohua; He, Jingsong

2016-05-01

From the constrained discrete Kadomtsev-Petviashvili (cdKP) hierarchy, the discrete nonlinear Schrödinger (DNLS) equations have been derived. By means of the gauge transformation, the Wronskian solution of DNLS equations have been given. The u1 of the cdKP hierarchy is a Y-type soliton solution for odd times of the gauge transformation, but it becomes a dark-bright soliton solution for even times of the gauge transformation. The role of the discrete variable n in the profile of the u1 is discussed.

Polarization-sensitive nanowire photodetectors based on solution-synthesized CdSe quantum-wire solids.

PubMed

Singh, Amol; Li, Xiangyang; Protasenko, Vladimir; Galantai, Gabor; Kuno, Masaru; Xing, Huili Grace; Jena, Debdeep

2007-10-01

Polarization-sensitive photodetectors are demonstrated using solution-synthesized CdSe nanowire (NW) solids. Photocurrent action spectra taken with a tunable white light source match the solution linear absorption spectra of the NWs, showing that the NW network is responsible for the device photoconductivity. Temperature-dependent transport measurements reveal that carriers responsible for the dark current through the nanowire solids are thermally excited across CdSe band gap. The NWs are aligned using dielectrophoresis between prepatterned electrodes using conventional optical photolithography. The photocurrent through the NW solid is found to be polarization-sensitive, consistent with complementary absorption (emission) measurements of both single wires and their ensembles. The range of solution-processed semiconducting NW materials, their facile synthesis, ease of device fabrication, and compatibility with a variety of substrates make them attractive for potential nanoscale polarization-sensitive photodetectors.

Surface analytical study of CuInSe[sub 2] treated in Cd-containing partial electrolyte solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asher, S.E.; Ramanathan, K.; Wiesner, H.

1999-03-01

Junction formation in CuInSe[sub 2] (CIS) has been studied by exposing thin films and single-crystal samples to solutions containing NH[sub 4]OH and CdSO[sub 4]. The treated samples were analyzed by secondary ion mass spectrometry to determine the amount and distribution of Cd deposited on the surface of the films. Cadmium is found to react with the surface for all the solution exposure times and temperatures studied. The reaction rapidly approaches the endpoint and remains relatively unchanged for subsequent solution exposure. Cadmium in-diffusion, as measured by secondary ion mass spectrometry, is obscured by topography effects in the thin-film samples and bymore » ion-beam mixing and topography in the single-crystal sample. [copyright] [ital 1999 American Institute of Physics.]« less

Surface analytical study of CuInSe{sub 2} treated in Cd-containing partial electrolyte solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asher, S.E.; Ramanathan, K.; Wiesner, H.

1999-03-01

Junction formation in CuInSe{sub 2} (CIS) has been studied by exposing thin films and single-crystal samples to solutions containing NH{sub 4}OH and CdSO{sub 4}. The treated samples were analyzed by secondary ion mass spectrometry to determine the amount and distribution of Cd deposited on the surface of the films. Cadmium is found to react with the surface for all the solution exposure times and temperatures studied. The reaction rapidly approaches the endpoint and remains relatively unchanged for subsequent solution exposure. Cadmium in-diffusion, as measured by secondary ion mass spectrometry, is obscured by topography effects in the thin-film samples and bymore » ion-beam mixing and topography in the single-crystal sample. {copyright} {ital 1999 American Institute of Physics.}« less

Enhanced visible-light-driven photocatalytic H2-production activity of CdS-loaded TiO2 microspheres with exposed (001) facets

NASA Astrophysics Data System (ADS)

Gao, Bifen; Yuan, Xia; Lu, Penghui; Lin, Bizhou; Chen, Yilin

2015-12-01

CdS-loaded TiO2 microspheres with highly exposed (001) facets were prepared by hydrothermal treatment of a TiF4-HCl-H2O mixed solution followed by a chemical bath deposition of CdS onto TiO2 microspheres. The crystal structure, surficial micro-structure and photo-absorption property of the samples were characterized by XRD, FE-SEM, TEM and UV-vis diffuse reflectance spectroscopy, etc. The as-prepared samples exhibited superior visible-light-driven photocatalytic H2-production activity from lactic acid aqueous solution in comparison with CdS-sensitized TiO2 nanoparticles, whose surface was dominated by (101) facets. Photoelectrochemical measurement confirmed that (001) facet is beneficial for the transfer of photo-generated electron from CdS to TiO2 microsphere, which led to the unexpected high photocatalytic activity of CdS-loaded TiO2 microspheres.

Characterization of potassium dichromate solutions for spectrophotometercalibration

NASA Astrophysics Data System (ADS)

Conceição, F. C.; Silva, E. M.; Gomes, J. F. S.; Borges, P. P.

2018-03-01

Spectrophotometric analysis in the ultraviolet (UV) region is used in the determination of several quantitative and qualitative parameters. For ensuring reliability of the analyses performed on the spectrophotometers, verification / calibration of the equipment must be performed periodically using certified reference materials (CRMs). This work presents the characterization stage needed for producing this CRM. The property value characterized was the absorbance for the wavelengths in the UV spectral regions. This CRM will contribute to guarantee the accuracy and linearity of the absorbance scale to the spectrophotometers, through which analytical measurement results will be provided with metrological traceability.

Controlling Wafer Contamination Using Automated On-Line Metrology during Wet Chemical Cleaning

NASA Astrophysics Data System (ADS)

Wang, Jason; Kingston, Skip; Han, Ye; Saini, Harmesh; McDonald, Robert; Mui, Rudy

2003-09-01

The capabilities of a trace contamination analyzer are discussed and demonstrated. This analytical tool utilizes an electrospray, time-of-flight mass spectrometer (ES-TOF-MS) for fully automated on-line monitoring of wafer cleaning solutions. The analyzer provides rich information on metallic, anionic, cationic, elemental, and organic species through its ability to provide harsh (elemental) and soft (molecular) ionization under both positive and negative modes. It is designed to meet semiconductor process control and yield management needs for the ever increasing complex new chemistries present in wafer fabrication.

Materials Science Laboratory

NASA Technical Reports Server (NTRS)

Jackson, Dionne

2005-01-01

The NASA Materials Science Laboratory (MSL) provides science and engineering services to NASA and Contractor customers at KSC, including those working for the Space Shuttle. International Space Station. and Launch Services Programs. These services include: (1) Independent/unbiased failure analysis (2) Support to Accident/Mishap Investigation Boards (3) Materials testing and evaluation (4) Materials and Processes (M&P) engineering consultation (5) Metrology (6) Chemical analysis (including ID of unknown materials) (7) Mechanical design and fabrication We provide unique solutions to unusual and urgent problems associated with aerospace flight hardware, ground support equipment and related facilities.

Cadmium accumulation in the rootless macrophyte Wolffia globosa and its potential for phytoremediation.

PubMed

Xie, Wan-Ying; Huang, Qing; Li, Gang; Rensing, Christopher; Zhu, Yong-Guan

2013-01-01

Cadmium (Cd) pollution around the world is a serious issue demanding acceptable solutions, one of which is phytoremediation that is both cost-effective and eco-friendly. Removal of Cd from contaminated water using plants with high growth rates and sufficient Cd accumulation abilities could be an appropriate choice. Here, we investigated a potential Cd accumulator, Wolffia, a rootless duckweed with high growth rate. Cd uptake, accumulation, tolerance, and phytofiltration ability by Wolffia globosa were examined. Furthermore, the effects of arsenic (As) on Cd uptake and phytofiltration by W. globosa were also studied. Cd uptake kinetics showed a linear pattern and a hyperbolic pattern without a plateau in lower (0-2 microM) and higher (0-200 microM) Cd concentration ranges, respectively, suggesting rapid Cd uptake by W. globosa Cd accumulation ability by W. globosa was higher at Cd concentrations < 10 microM than at >10 microM. All the five species of Wolffia exposed to I microM Cd for 5 days accumulated > 500 mg Cd kg(-1) DW. Ten gram fresh W. globosa could diminish almost all the Cd (2 microM) in a 200 mL solution. This enormous accumulation ability was mostly due to passive adsorption of Cd by the apoplast. Arsenic had no significant effect on Cd uptake and phytofiltration. The fresh fronds also showed a great As extracting ability. The results indicated that Wolffia is a strong Cd accumulator and has great Cd phytoremediation potential. Therefore, this plant can be used in fresh aquatic environments co-contaminated by low-levels of Cd and As.

Efficiency and mechanisms of Cd removal from aqueous solution by biochar derived from water hyacinth (Eichornia crassipes).

PubMed

Zhang, Feng; Wang, Xin; Yin, Daixia; Peng, Bo; Tan, Changyin; Liu, Yunguo; Tan, Xiaofei; Wu, Shixue

2015-04-15

This study investigated the efficiency and mechanisms of Cd removal by biochar pyrolyzed from water hyacinth (BC) at 250-550 °C. BC450 out-performed the other BCs at varying Cd concentrations and can remove nearly 100% Cd from aqueous solution within 1 h at initial Cd ≤ 50 mg l(-1). The process of Cd sorption by BC450 followed the pseudo-second order kinetics with the equilibrium being achieved after 24 h with initial Cd ranging from 100 to 500 mg l(-1). The maximum Cd sorption capacity of BC450 was estimated to be 70.3 mg g(-1) based on Langmuir model, which is prominent among a range of low-cost sorbents. Based on the balance analysis between cations released and Cd sorbed onto BC450 in combination with SEM-EDX and XPS data, ion-exchange followed by surface complexation is proposed as the dominant mechanism responsible for Cd immobilization by BC450. In parallel, XRD analysis also suggested the formation of insoluble Cd minerals (CdCO3, Cd3P2, Cd3(PO4)2 and K4CdCl6) from either (co)-precipitation or ion exchange. Results from this study highlighted that the conversion of water hyacinth into biochar is a promising method to achieve effective Cd immobilization and improved management of this highly problematic invasive species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Template-free solution approach to synthesize CdS dendrites with SCN based ionic liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Kangfeng; Li, Jiajia; Cheng, Xianyi

2011-07-15

Highlights: {yields} Template-free solution approach to synthesize CdS hierarchical dendrites. {yields} The 1-butyl-3-methlyimidazole thiocyanate ([BMIM][SCN]) plays doubly functional roles in the progress. {yields} The CdS hierarchical dendrites exhibit a more intense emission at 710 nm belongs to infrared band. -- Abstract: Cadmium sulfide dendrites were synthesized by a facile hydrothermal treatment from CdCl{sub 2} and ionic liquid 1-butyl-3-methlyimidazole thiocyanate acted both as sulfur source and surfactant. The product was characterized by means of X-ray powder diffraction and scanning electron microscopy. X-ray powder diffraction studies indicated that the product was well-crystallized hexagonal phase of CdS, and the scanning electron microscopy imagesmore » showed that the obtained powders consisted of a wealth of well-defined CdS dendritic microstructures with a pronounced trunk and highly ordered branches. The UV-Vis and photoluminescence spectroscopy measurements were taken as well. The possible formation mechanism of CdS dendrites was simply proposed in the end.« less

JPRS Report, Science & Technology, USSR: Science & Technology Policy

DTIC Science & Technology

1988-04-05

associa- tions—were formulated. Specialists, A. V. Glichev, direc- tor of the All-Union Institute of Metrology and Stan- dardization of the USSR State...Various functional subdi- visions—laboratories of reliability, metrological labora- tories, monitoring and diagnostic centers, and so forth— are...department for standards, metrology , and quality. The latter annually does not approve and sends back for modification up to 20 of the "notebooks of

Integrating Residual Stress Analysis of Critical Fastener Holes into USAF Depot Maintenance

DTIC Science & Technology

2014-11-02

40 Table 15. Metrology of the initial reamer, initial hole diameters, and resulting CX for the class/type hole combinations for Pattern 1...70 Table 16. Metrology of the initial reamer, initial hole diameters, and resulting...step in the cold work process. These procedures produce a digital documentation of the hole, based on critical metrology , which can be linked with

In-Process Metrology And Control Of Large Optical Grinders

NASA Astrophysics Data System (ADS)

Anderson, D. S.; Ketelsen, D.; Kittrell, W. Cary; Kuhn, Wm; Parks, R. E.; Stahl, P.

1987-01-01

The advent of rapid figure generation at the University of Arizona has prompted the development of rapid metrology techniques. The success and efficiency of the generating process is highly dependent on timely and accurate measurements to update the feedback loop between machine and optician. We will describe the advantages and problems associated with the in-process metrology and control systems used at the Optical Sciences Center.

Preparation and certification of arsenate [As(V)] reference material, NMIJ CRM 7912-a.

PubMed

Narukawa, Tomohiro; Kuroiwa, Takayoshi; Narushima, Izumi; Jimbo, Yasujiro; Suzuki, Toshihiro; Chiba, Koichi

2010-05-01

Arsenate [As(V)] solution reference material, National Metrology Institute of Japan (NMIJ) certified reference material (CRM) 7912-a, for speciation of arsenic species was developed and certified by NMIJ, the National Institute of Advanced Industrial Science and Technology. High-purity As(2)O(3) reagent powder was dissolved in 0.8 M HNO(3) solution and As(III) was oxidized to As(V) with HNO(3) to prepare 100 mg kg(-1) of As(V) candidate CRM solution. The solution was bottled in 400 bottles (50 mL each). The concentration of As(V) was determined by four independent analytical techniques-inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectrometry, graphite furnace atomic absorption spectrometry, and liquid chromatography inductively coupled plasma mass spectrometry-according to As(V) calibration solutions, which were prepared from the arsenic standard of the Japan Calibration Service system and whose species was guaranteed to be As(V) by NMIJ. The uncertainties of all the measurements and preparation procedures were evaluated. The certified value of As(V) in the CRM is (99.53 +/- 1.67) mg kg(-1) (k = 2).

Temporal dissolution of potentially toxic elements from silver smelting slag by synthetic environmental solutions.

PubMed

Ash, Christopher; Borůvka, Luboš; Tejnecký, Václav; Šebek, Ondřej; Nikodem, Antonín; Drábek, Ondřej

2013-11-15

Waste slag which is created during precious metal smelting contains high levels of potentially toxic elements (PTE) which can be mobilised from unconfined deposits into the local environment. This paper examines the extractability of selected PTE (Pb, Zn, Cd, Mn) from slag samples by synthetic solutions designed to replicate those in the environment. Extracting agents were used to replicate potential leaching scenarios which are analogous to natural chemical weathering. Slag was submersed in a rainwater simulation solution (RSS), weak citric acid solution (representing rhizosphere secretions) and control solutions (deionised water) for a one month period with solution analyses made at intervals of 1, 24, 168 and 720 h. In 1 mM citric acid, dissolution of Cd and Zn showed little change with time, although for Zn the initial dissolution was considerable. Lead in citric acid was characterized by overall poor extractability. Mn solubility increased until an equilibrium state occurred within 24 h. The solubility of studied metals in citric acid can be characterized by a short time to equilibrium. RSS proved to be an effective solvent that, unlike citric acid solution, extracted increasing concentrations of Cd, Mn and Zn with time. Solubility of Pb in RSS was again very low. When taken as a proportion of a single 2 M HNO3 extraction which was applied to slag samples, Cd was the element most readily leached into RSS and control samples. In both studied solvents, slag heterogeneity is prominent in the case of Cd and Zn solubility. Contact time with solvent appears to be an important variable for the release of PTE from slag into solution. The purpose of this study was to provide insight into the environmental chemical dissolution of PTE from slag, which causes their enrichment in surrounding soils and surface waters. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluation of carbon nanotube probes in critical dimension atomic force microscopes.

PubMed

Choi, Jinho; Park, Byong Chon; Ahn, Sang Jung; Kim, Dal-Hyun; Lyou, Joon; Dixson, Ronald G; Orji, Ndubuisi G; Fu, Joseph; Vorburger, Theodore V

2016-07-01

The decreasing size of semiconductor features and the increasing structural complexity of advanced devices have placed continuously greater demands on manufacturing metrology, arising both from the measurement challenges of smaller feature sizes and the growing requirement to characterize structures in more than just a single critical dimension. For scanning electron microscopy, this has resulted in increasing sophistication of imaging models. For critical dimension atomic force microscopes (CD-AFMs), this has resulted in the need for smaller and more complex tips. Carbon nanotube (CNT) tips have thus been the focus of much interest and effort by a number of researchers. However, there have been significant issues surrounding both the manufacture and use of CNT tips. Specifically, the growth or attachment of CNTs to AFM cantilevers has been a challenge to the fabrication of CNT tips, and the flexibility and resultant bending artifacts have presented challenges to using CNT tips. The Korea Research Institute for Standards and Science (KRISS) has invested considerable effort in the controlled fabrication of CNT tips and is collaborating with the National Institute of Standards and Technology on the application of CNT tips for CD-AFM. Progress by KRISS on the precise control of CNT orientation, length, and end modification, using manipulation and focused ion beam processes, has allowed us to implement ball-capped CNT tips and bent CNT tips for CD-AFM. Using two different generations of CD-AFM instruments, we have evaluated these tip types by imaging a line/space grating and a programmed line edge roughness specimen. We concluded that these CNTs are capable of scanning the profiles of these structures, including re-entrant sidewalls, but there remain important challenges to address. These challenges include tighter control of tip geometry and careful optimization of scan parameters and algorithms for using CNT tips.

On CD-AFM bias related to probe bending

NASA Astrophysics Data System (ADS)

Ukraintsev, V. A.; Orji, N. G.; Vorburger, T. V.; Dixson, R. G.; Fu, J.; Silver, R. M.

2012-03-01

Critical Dimension AFM (CD-AFM) is a widely used reference metrology. To characterize modern semiconductor devices, very small and flexible probes, often 15 nm to 20 nm in diameter, are now frequently used. Several recent publications have reported on uncontrolled and significant probe-to-probe bias variation during linewidth and sidewall angle measurements [1,2]. Results obtained in this work suggest that probe bending can be on the order of several nanometers and thus potentially can explain much of the observed CD-AFM probe-to-probe bias variation. We have developed and experimentally tested one-dimensional (1D) and two-dimensional (2D) models to describe the bending of cylindrical probes. An earlier 1D bending model reported by Watanabe et al. [3] was refined. Contributions from several new phenomena were considered, including: probe misalignment, diameter variation near the carbon nanotube tip (CNT) apex, probe bending before snapping, distributed van der Waals-London force, etc. The methodology for extraction of the Hamaker probe-surface interaction energy from experimental probe bending data was developed. To overcome limitations of the 1D model, a new 2D distributed force (DF) model was developed. Comparison of the new model with the 1D single point force (SPF) model revealed about 27 % difference in probe bending bias between the two. A simple linear relation between biases predicted by the 1D SPF and 2D DF models was found. This finding simplifies use of the advanced 2D DF model of probe bending in various CD-AFM applications. New 2D and three-dimensional (3D) CDAFM data analysis software is needed to take full advantage of the new bias correction modeling capabilities.

Sharing from Scratch: How To Network CD-ROM.

ERIC Educational Resources Information Center

Doering, David

1998-01-01

Examines common CD-ROM networking architectures: via existing operating systems (OS), thin server towers, and dedicated servers. Discusses digital video disc (DVD) and non-CD/DVD optical storage solutions and presents case studies of networks that work. (PEN)

The use of linear expressions of solute boiling point versus retention to indicate special interactions with the molecular rings of modified cyclodextrin phases in gas chromatography

PubMed

Betts

2000-08-01

The boiling points (degrees C, 1 x 10) of diverse C10 polar solutes from volatile oils are set against their relative retention times versus n-undecane to calculate linear equations for 12 commercial modified cyclodextrin (CD) capillary phases. Ten data points are considered for each CD, then solutes are rejected until 5 or more remain that give an expression with a correlation coefficient of at least 0.990 and a standard deviation of less than 5.5. Three phases give almost perfect correlation, and 3 other CDs have difficulty complying. Solutes involved in the equations (most frequently cuminal, linalol, and carvone) are presumed to have a 'standard' polar transient interaction with the molecular rings of the CDs concerned. Several remaining solutes (mostly citral, fenchone, and menthol) exhibit extra retention over the calculated standard (up to 772%), which is believed to indicate a firm 'host' CD or 'guest' solute molecular fit in some cases. Other solutes show less retention than calculated (mostly citronellal, citronellol, estragole, and pulegone). This suggests rejection by the CD, which behaves merely as a conventional stationary phase to them. The intercept constant in the equation for each phase is suggested to be a numerical relative polarity indicator. These b values indicate that 3 hydroxypropyl CDs show the most polarity with values from 28 to 43; and CDs that are fully substituted with inert groups fall in the range of 15 to 20.

Laser metrology and optic active control system for GAIA

NASA Astrophysics Data System (ADS)

D'Angelo, F.; Bonino, L.; Cesare, S.; Castorina, G.; Mottini, S.; Bertinetto, F.; Bisi, M.; Canuto, E.; Musso, F.

2017-11-01

The Laser Metrology and Optic Active Control (LM&OAC) program has been carried out under ESA contract with the purpose to design and validate a laser metrology system and an actuation mechanism to monitor and control at microarcsec level the stability of the Basic Angle (angle between the lines of sight of the two telescopes) of GAIA satellite. As part of the program, a breadboard (including some EQM elements) of the laser metrology and control system has been built and submitted to functional, performance and environmental tests. In the followings we describe the mission requirements, the system architecture, the breadboard design, and finally the performed validation tests. Conclusion and appraisals from this experience are also reported.

Non-null full field X-ray mirror metrology using SCOTS: a reflection deflectometry approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su P.; Kaznatcheev K.; Wang, Y.

In a previous paper, the University of Arizona (UA) has developed a measurement technique called: Software Configurable Optical Test System (SCOTS) based on the principle of reflection deflectometry. In this paper, we present results of this very efficient optical metrology method applied to the metrology of X-ray mirrors. We used this technique to measure surface slope errors with precision and accuracy better than 100 nrad (rms) and {approx}200 nrad (rms), respectively, with a lateral resolution of few mm or less. We present results of the calibration of the metrology systems, discuss their accuracy and address the precision in measuring amore » spherical mirror.« less

Solution-Processed Transistors Using Colloidal Nanocrystals with Composition-Matched Molecular "Solders": Approaching Single Crystal Mobility.

PubMed

Jang, Jaeyoung; Dolzhnikov, Dmitriy S; Liu, Wenyong; Nam, Sooji; Shim, Moonsub; Talapin, Dmitri V

2015-10-14

Crystalline silicon-based complementary metal-oxide-semiconductor transistors have become a dominant platform for today's electronics. For such devices, expensive and complicated vacuum processes are used in the preparation of active layers. This increases cost and restricts the scope of applications. Here, we demonstrate high-performance solution-processed CdSe nanocrystal (NC) field-effect transistors (FETs) that exhibit very high carrier mobilities (over 400 cm(2)/(V s)). This is comparable to the carrier mobilities of crystalline silicon-based transistors. Furthermore, our NC FETs exhibit high operational stability and MHz switching speeds. These NC FETs are prepared by spin coating colloidal solutions of CdSe NCs capped with molecular solders [Cd2Se3](2-) onto various oxide gate dielectrics followed by thermal annealing. We show that the nature of gate dielectrics plays an important role in soldered CdSe NC FETs. The capacitance of dielectrics and the NC electronic structure near gate dielectric affect the distribution of localized traps and trap filling, determining carrier mobility and operational stability of the NC FETs. We expand the application of the NC soldering process to core-shell NCs consisting of a III-V InAs core and a CdSe shell with composition-matched [Cd2Se3](2-) molecular solders. Soldering CdSe shells forms nanoheterostructured material that combines high electron mobility and near-IR photoresponse.

Effect of aniline on cadmium adsorption by sulfanilic acid-grafted magnetic graphene oxide sheets.

PubMed

Hu, Xin-jiang; Liu, Yun-guo; Zeng, Guang-ming; Wang, Hui; Hu, Xi; Chen, An-wei; Wang, Ya-qin; Guo, Yi-Mming; Li, Ting-ting; Zhou, Lu; Liu, Shao-heng; Zeng, Xiao-xia

2014-07-15

Cd(II) has posed severe health risks worldwide. To remove this contaminant from aqueous solution, the sulfanilic acid-grafted magnetic graphene oxide sheets (MGOs/SA) were prepared and characterized. The mutual effects of Cd(II) and aniline adsorption on MGOs/SA were studied. The effects of operating parameters such as pH, ionic strength, contact time and temperature on the Cd(II) enrichment, as well as the adsorption kinetics and isotherm were also investigated. The results demonstrated that MGOs/SA could effectively remove Cd(II) and aniline from the aqueous solution and the two adsorption processes were strongly dependent on solution pH. The Cd(II) adsorption was reduced by the presence of aniline at pH<5.4 but was improved at pH>5.4. The presence of Cd(II) diminished the adsorption capacity for aniline at pH<7.8 but enhanced the aniline adsorption at pH>7.8. The decontamination of Cd(II) by MGOs/SA was influenced by ionic strength. Besides, the adsorption process could be well described by pseudo-second-order kinetic model. The intraparticle diffusion study revealed that the intraparticle diffusion was not the only rate-limiting step for the adsorption process. Moreover, the experimental data of isotherm followed the Freundlich isotherm model. Copyright © 2014 Elsevier Inc. All rights reserved.

CdS/ZnS nanocomposites: from mechanochemical synthesis to cytotoxicity issues.

PubMed

Baláž, Peter; Baláž, Matej; Dutková, Erika; Zorkovská, Anna; Kováč, Jaroslav; Hronec, Pavol; Kováč, Jaroslav; Čaplovičová, Mária; Mojžiš, Ján; Mojžišová, Gabriela; Eliyas, Alexander; Kostova, Nina G

2016-01-01

CdS/ZnS nanocomposites have been prepared by a two-step solid-state mechanochemical synthesis. CdS has been prepared from cadmium acetate and sodium sulfide precursors in the first step. The obtained cubic CdS (hawleyite, JCPDS 00-010-0454) was then mixed in the second step with the cubic ZnS (sphalerite, JCPDS 00-005-0566) synthesized mechanochemically from the analogous precursors. The crystallite sizes of the new type CdS/ZnS nanocomposite, calculated based on the XRD data, were 3-4 nm for both phases. The synthesized nanoparticles have been further characterized by high-resolution transmission electron microscopy (HRTEM) and micro-photoluminescence (μPL) spectroscopy. The PL emission peaks in the PL spectra are attributed to the recombination of holes/electrons in the nanocomposites occurring in depth associated with Cd, Zn vacancies and S interstitials. Their photocatalytic activity was also measured. In the photocatalytic activity tests to decolorize Methyl Orange dye aqueous solution, the process is faster and its effectivity is higher when using CdS/ZnS nanocomposite, compared to single phase CdS. Very low cytotoxic activity (high viability) of the cancer cell lines (selected as models of living cells) has been evidenced for CdS/ZnS in comparison with CdS alone. This fact is in a close relationship with Cd(II) ions dissolution tested in a physiological solution. The concentration of cadmium dissolved from CdS/ZnS nanocomposites with variable Cd:Zn ratio was 2.5-5.0 μg.mL(-1), whereas the concentration for pure CdS was much higher - 53 μg.ml(-1). The presence of ZnS in the nanocrystalline composite strongly reduced the release of cadmium into the physiological solution, which simulated the environment in the human body. The obtained CdS/ZnS quantum dots can serve as labeling media and co-agents in future anti-cancer drugs, because of their potential in theranostic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermodynamic studies of drug-alpha-cyclodextrin interactions in water at 298.15 K: promazine hydrochloride/chlorpromazine hydrochloride + alpha-cyclodextrin + H(2)O systems.

PubMed

Terdale, Santosh S; Dagade, Dilip H; Patil, Kesharsingh J

2007-12-06

Data on osmotic coefficients have been obtained for a binary aqueous solution of two drugs, namely, promazine hydrochloride (PZ) and chlorpromazine hydrochloride (CPZ) using a vapor pressure osmometer at 298.15 K. The observed critical micelle concentration (cmc) agrees excellently with the available literature data. The measurements are extended to aqueous ternary solutions containing fixed a concentration of alpha-cyclodextrin (alpha-CD) of 0.1 mol kg(-1) and varied concentrations (approximately 0.005-0.2 mol kg(-1)) of drugs at 298.15 K. It has been found that the cmc values increase by the addition of alpha-CD. The mean molal activity coefficients of the ions and the activity coefficient of alpha-CD in binary as well as ternary solutions were obtained, which have been further used to calculate the excess Gibbs free energies and transfer Gibbs free energies. The lowering of the activity coefficients of ions and of alpha-CD is attributed to the existence of host-guest (inclusion)-type complex equilibria. It is suggested that CPZ forms 2:1 and 1:1 complexed species with alpha-CD, while PZ forms only 1:1 complexed species. The salting constant (ks) values are determined at 298.15 K for promazine-alpha-CD and chlorpromazine-alpha-CD complexes, respectively, by following the method based on the application of the McMillan-Mayer theory of virial coefficients to transfer free energy data. It is noted that the presence of chlorine in the drug molecule imparts better complexing capacity, the effect of which gets attenuated as a result of hydrophobic interaction. The results are discussed from the point of view of associative equilibria before the cmc and complexed equilibria for binary and ternary solutions, respectively.

Cadmium accumulation by muskmelon under salt stress in contaminated organic soil.

PubMed

Ondrasek, Gabrijel; Gabrijel, Ondrasek; Romic, Davor; Davor, Romic; Rengel, Zed; Zed, Rengel; Romic, Marija; Marija, Romic; Zovko, Monika; Monika, Zovko

2009-03-15

Human-induced salinization and trace element contamination are widespread and increasing rapidly, but their interactions and environmental consequences are poorly understood. Phytoaccumulation, as the crucial entry pathway for biotoxic Cd into the human foodstuffs, correlates positively with rhizosphere salinity. Hypothesising that organic matter decreases the bioavailable Cd(2+) pool and therefore restricts its phytoextraction, we assessed the effects of four salinity levels (0, 20, 40 and 60 mM NaCl) and three Cd levels (0.3, 5.5 and 10.4 mg kg(-1)) in peat soil on mineral accumulation/distribution as well as vegetative growth and fruit yield parameters of muskmelon (Cucumis melo L.) in a greenhouse. Salt stress reduced shoot biomass and fruit production, accompanied by increased Na and Cl and decreased K concentration in above-ground tissues. A 25- and 50-day exposure to salinity increased Cd accumulation in leaves up to 87% and 46%, respectively. Accumulation of Cd in the fruits was up to 43 times lower than in leaves and remained unaltered by salinity. Soil contamination by Cd enhanced its accumulation in muskmelon tissues by an order of magnitude compared with non-contaminated control. In the drainage solution, concentrations of Na and Cl slightly exceeded those in the irrigation solution, whereas Cd concentration in drainage solution was lower by 2-3 orders of magnitude than the total amount added. Chemical speciation and distribution modelling (NICA-Donnan) using Visual MINTEQ showed predominance of dissolved organic ligands in Cd chemisorption and complexation in all treatments; however, an increase in salt addition caused a decrease in organic Cd complexes from 99 to 71%, with free Cd(2+) increasing up to 6% and Cd-chlorocomplexes up to 23%. This work highlights the importance of soil organic reactive surfaces in reducing trace element bioavailability and phytoaccumulation. Chloride salinity increased Cd accumulation in leaves but not in fruit peel and pulp.

Digital terrain modeling and industrial surface metrology: Converging realms

USGS Publications Warehouse

Pike, R.J.

2001-01-01

Digital terrain modeling has a micro-and nanoscale counterpart in surface metrology, the numerical characterization of industrial surfaces. Instrumentation in semiconductor manufacturing and other high-technology fields can now contour surface irregularities down to the atomic scale. Surface metrology has been revolutionized by its ability to manipulate square-grid height matrices that are analogous to the digital elevation models (DEMs) used in physical geography. Because the shaping of industrial surfaces is a spatial process, the same concepts of analytical cartography that represent ground-surface form in geography evolved independently in metrology: The surface topography of manufactured components, exemplified here by automobile-engine cylinders, is routinely modeled by variogram analysis, relief shading, and most other techniques of parameterization and visualization familiar to geography. This article introduces industrial surface-metrology, examines the field in the context of terrain modeling and geomorphology and notes their similarities and differences, and raises theoretical issues to be addressed in progressing toward a unified practice of surface morphometry.

Speckle-based portable device for in-situ metrology of x-ray mirrors at Diamond Light Source

NASA Astrophysics Data System (ADS)

Wang, Hongchang; Kashyap, Yogesh; Zhou, Tunhe; Sawhney, Kawal

2017-09-01

For modern synchrotron light sources, the push toward diffraction-limited and coherence-preserved beams demands accurate metrology on X-ray optics. Moreover, it is important to perform in-situ characterization and optimization of X-ray mirrors since their ultimate performance is critically dependent on the working conditions. Therefore, it is highly desirable to develop a portable metrology device, which can be easily implemented on a range of beamlines for in-situ metrology. An X-ray speckle-based portable device for in-situ metrology of synchrotron X-ray mirrors has been developed at Diamond Light Source. Ultra-high angular sensitivity is achieved by scanning the speckle generator in the X-ray beam. In addition to the compact setup and ease of implementation, a user-friendly graphical user interface has been developed to ensure that characterization and alignment of X-ray mirrors is simple and fast. The functionality and feasibility of this device is presented with representative examples.

EQ-10 electrodeless Z-pinch EUV source for metrology applications

NASA Astrophysics Data System (ADS)

Gustafson, Deborah; Horne, Stephen F.; Partlow, Matthew J.; Besen, Matthew M.; Smith, Donald K.; Blackborow, Paul A.

2011-11-01

With EUV Lithography systems shipping, the requirements for highly reliable EUV sources for mask inspection and resist outgassing are becoming better defined, and more urgent. The sources needed for metrology applications are very different than that needed for lithography; brightness (not power) is the key requirement. Suppliers for HVM EUV sources have all resources working on high power and have not entered the smaller market for metrology. Energetiq Technology has been shipping the EQ-10 Electrodeless Z-pinchTM light source since 19951. The source is currently being used for metrology, mask inspection, and resist development2-4. These applications require especially stable performance in both output power and plasma size and position. Over the last 6 years Energetiq has made many source modifications which have included better thermal management to increase the brightness and power of the source. We now have introduced a new source that will meet requirements of some of the mask metrology first generation tools; this source will be reviewed.

Metrological analysis of a virtual flowmeter-based transducer for cryogenic helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arpaia, P., E-mail: pasquale.arpaia@unina.it; Technology Department, European Organization for Nuclear Research; Girone, M., E-mail: mario.girone@cern.ch

2015-12-15

The metrological performance of a virtual flowmeter-based transducer for monitoring helium under cryogenic conditions is assessed. At this aim, an uncertainty model of the transducer, mainly based on a valve model, exploiting finite-element approach, and a virtual flowmeter model, based on the Sereg-Schlumberger method, are presented. The models are validated experimentally on a case study for helium monitoring in cryogenic systems at the European Organization for Nuclear Research (CERN). The impact of uncertainty sources on the transducer metrological performance is assessed by a sensitivity analysis, based on statistical experiment design and analysis of variance. In this way, the uncertainty sourcesmore » most influencing metrological performance of the transducer are singled out over the input range as a whole, at varying operating and setting conditions. This analysis turns out to be important for CERN cryogenics operation because the metrological design of the transducer is validated, and its components and working conditions with critical specifications for future improvements are identified.« less

Performance of ASML YieldStar μDBO overlay targets for advanced lithography nodes C028 and C014 overlay process control

NASA Astrophysics Data System (ADS)

Blancquaert, Yoann; Dezauzier, Christophe; Depre, Jerome; Miqyass, Mohamed; Beltman, Jan

2013-04-01

Continued tightening of overlay control budget in semiconductor lithography drives the need for improved metrology capabilities. Aggressive improvements are needed for overlay metrology speed, accuracy and precision. This paper is dealing with the on product metrology results of a scatterometry based platform showing excellent production results on resolution, precision, and tool matching for overlay. We will demonstrate point to point matching between tool generations as well as between target sizes and types. Nowadays, for the advanced process nodes a lot of information is needed (Higher order process correction, Reticle fingerprint, wafer edge effects) to quantify process overlay. For that purpose various overlay sampling schemes are evaluated: ultra- dense, dense and production type. We will show DBO results from multiple target type and shape for on product overlay control for current and future node down to at least 14 nm node. As overlay requirements drive metrology needs, we will evaluate if the new metrology platform meets the overlay requirements.

Metrology for hydrogen energy applications: a project to address normative requirements

NASA Astrophysics Data System (ADS)

Haloua, Frédérique; Bacquart, Thomas; Arrhenius, Karine; Delobelle, Benoît; Ent, Hugo

2018-03-01

Hydrogen represents a clean and storable energy solution that could meet worldwide energy demands and reduce greenhouse gases emission. The joint research project (JRP) ‘Metrology for sustainable hydrogen energy applications’ addresses standardisation needs through pre- and co-normative metrology research in the fast emerging sector of hydrogen fuel that meet the requirements of the European Directive 2014/94/EU by supplementing the revision of two ISO standards that are currently too generic to enable a sustainable implementation of hydrogen. The hydrogen purity dispensed at refueling points should comply with the technical specifications of ISO 14687-2 for fuel cell electric vehicles. The rapid progress of fuel cell technology now requires revising this standard towards less constraining limits for the 13 gaseous impurities. In parallel, optimized validated analytical methods are proposed to reduce the number of analyses. The study aims also at developing and validating traceable methods to assess accurately the hydrogen mass absorbed and stored in metal hydride tanks; this is a research axis for the revision of the ISO 16111 standard to develop this safe storage technique for hydrogen. The probability of hydrogen impurity presence affecting fuel cells and analytical techniques for traceable measurements of hydrogen impurities will be assessed and new data of maximum concentrations of impurities based on degradation studies will be proposed. Novel validated methods for measuring the hydrogen mass absorbed in hydrides tanks AB, AB2 and AB5 types referenced to ISO 16111 will be determined, as the methods currently available do not provide accurate results. The outputs here will have a direct impact on the standardisation works for ISO 16111 and ISO 14687-2 revisions in the relevant working groups of ISO/TC 197 ‘Hydrogen technologies’.

Room-temperature synthesis of Zn(0.80)Cd(0.20)S solid solution with a high visible-light photocatalytic activity for hydrogen evolution.

PubMed

Wang, Dong-Hong; Wang, Lei; Xu, An-Wu

2012-03-21

Visible light photocatalytic H(2) production from water splitting is of great significance for its potential applications in converting solar energy into chemical energy. In this study, a series of Zn(1-x)Cd(x)S solid solutions with a nanoporous structure were successfully synthesized via a facile template-free method at room temperature. The obtained solid solutions were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS) and N(2) adsorption-desorption analysis. The solid solutions show efficient photocatalytic activity for H(2) evolution from aqueous solutions containing sacrificial reagents S(2-) and SO(3)(2-) under visible-light irradiation without a Pt cocatalyst, and loading of the Pt cocatalyst further improves the visible-light photocatalytic activity. The optimal photocatalyst with x = 0.20 prepared at pH = 7.3 displays the highest activity for H(2) evolution. The bare and 0.25 wt% Pt loaded Zn(0.80)Cd(0.20)S nanoparticles exhibit a high H(2) evolution rate of 193 μmol h(-1) and 458 μmol h(-1) under visible-light irradiation (λ ≥ 420 nm), respectively. In addition, the bare and 0.25 wt% Pt loaded Zn(0.80)Cd(0.20)S catalysts show a high H(2) evolution rate of 252 and 640 μmol h(-1) under simulated solar light irradiation, respectively. Moreover, the Zn(0.80)Cd(0.20)S catalyst displays a high photocatalytic stability for H(2) evolution under long-term light irradiation. The incorporation of Cd in the solid solution leads to the visible light absorption, and the high content of Zn in the solid solution results in a relatively negative conduction band, a modulated band gap and a rather wide valence bandwidth, which are responsible for the excellent photocatalytic performance of H(2) production and for the high photostability. This journal is © The Royal Society of Chemistry 2012

In-field Raman amplification on coherent optical fiber links for frequency metrology.

PubMed

Clivati, C; Bolognini, G; Calonico, D; Faralli, S; Mura, A; Levi, F

2015-04-20

Distributed Raman amplification (DRA) is widely exploited for the transmission of broadband, modulated signals used in data links, but not yet in coherent optical links for frequency metrology, where the requirements are rather different. After preliminary tests on fiber spools, in this paper we deeper investigate Raman amplification on deployed in-field optical metrological links. We actually test a Doppler-stabilized optical link both on a 94 km-long metro-network implementation with multiplexed ITU data channels and on a 180 km-long dedicated fiber haul connecting two cities, where DRA is employed in combination with Erbium-doped fiber amplification (EDFA). The performance of DRA is detailed in both experiments, indicating that it does not introduce noticeable penalties for the metrological signal or for the ITU data channels. We hence show that Raman amplification of metrological signals can be compatible with a wavelength division multiplexing architecture and that it can be used as an alternative or in combination with dedicated bidirectional EDFAs. No deterioration is noticed in the coherence properties of the delivered signal, which attains frequency instability at the 10(-19) level in both cases. This study can be of interest also in view of the undergoing deployment of continental fiber networks for frequency metrology.

The regulatory effects of resistant starch on glycaemic response in obese dogs.

PubMed

Kimura, Tohru

2013-12-01

The purpose of this study was to examine the inhibitory effects of resistant starch on postprandial glycaemic response in obese dogs. The changes in blood glucose concentrations and glycaemic index (GI) were chronologically determined after the administration of resistant and normal starches by nasal feeding. Resistant starch contained indigestible dextrin (IDD) and β-cyclic dextrin (β-CD). Soluble starch (SS) served as a control starch. Glucose concentrations reached their maximum 15 min after the administration of SS solutions, and decreased gradually during the experimental period. In contrast, after the administration of IDD solutions, increased glucose concentrations rapidly decreased to the initial values. After the administration of β-CD solutions, glucose concentrations remained unchanged during this study. GI levels remained constant in the following order: β-CD < IDD < SS. GI levels of dogs receiving IDD and β-CD solutions were significantly lower as compared with those animals receiving SS solutions. In this study, nasal tube feeding was an effective method for evaluating glycaemic responses to various starches accurately. The present data revealed that resistant starches were useful materials in controlling nutritionally glucose concentrations in obese dogs. These results raise the possibility that resistant starches are valuable for dietetic treatment of diabetes and obesity in dogs.

Feed-forward alignment correction for advanced overlay process control using a standalone alignment station "Litho Booster"

NASA Astrophysics Data System (ADS)

Yahiro, Takehisa; Sawamura, Junpei; Dosho, Tomonori; Shiba, Yuji; Ando, Satoshi; Ishikawa, Jun; Morita, Masahiro; Shibazaki, Yuichi

2018-03-01

One of the main components of an On-Product Overlay (OPO) error budget is the process induced wafer error. This necessitates wafer-to-wafer correction in order to optimize overlay accuracy. This paper introduces the Litho Booster (LB), standalone alignment station as a solution to improving OPO. LB can execute high speed alignment measurements without throughput (THP) loss. LB can be installed in any lithography process control loop as a metrology tool, and is then able to provide feed-forward (FF) corrections to the scanners. In this paper, the detailed LB design is described and basic LB performance and OPO improvement is demonstrated. Litho Booster's extendibility and applicability as a solution for next generation manufacturing accuracy and productivity challenges are also outlined

Error analysis in inverse scatterometry. I. Modeling.

PubMed

Al-Assaad, Rayan M; Byrne, Dale M

2007-02-01

Scatterometry is an optical technique that has been studied and tested in recent years in semiconductor fabrication metrology for critical dimensions. Previous work presented an iterative linearized method to retrieve surface-relief profile parameters from reflectance measurements upon diffraction. With the iterative linear solution model in this work, rigorous models are developed to represent the random and deterministic or offset errors in scatterometric measurements. The propagation of different types of error from the measurement data to the profile parameter estimates is then presented. The improvement in solution accuracies is then demonstrated with theoretical and experimental data by adjusting for the offset errors. In a companion paper (in process) an improved optimization method is presented to account for unknown offset errors in the measurements based on the offset error model.

Metrology - Beyond the Calibration Lab

NASA Technical Reports Server (NTRS)

Mimbs, Scott M.

2008-01-01

We rely on data from measurements every day; a gas-pump, a speedometer, and a supermarket weight scale are just three examples of measurements we use to make decisions. We generally accept the data from these measurements as "valid." One reason we can accept the data is the "legal metrology" requirements established and regulated by the government in matters of commerce. The measurement data used by NASA, other government agencies, and industry can be critical to decisions which affect everything from economic viability, to mission success, to the security of the nation. Measurement data can even affect life and death decisions. Metrology requirements must adequately provide for risks associated with these decisions. To do this, metrology must be integrated into all aspects of an industry including research, design, testing, and product acceptance. Metrology, the science of measurement, has traditionally focused on the calibration of instruments, and although instrument calibration is vital, it is only a part of the process that assures quality in measurement data. For example, measurements made in research can influence the fundamental premises that establish the design parameters, which then flow down to the manufacturing processes, and eventually impact the final product. Because a breakdown can occur anywhere within this cycle, measurement quality assurance has to be integrated into every part of the life-cycle process starting with the basic research and ending with the final product inspection process. The purpose of this paper is to discuss the role of metrology in the various phases of a product's life-cycle. For simplicity, the cycle will be divided in four broad phases, with discussions centering on metrology within NASA. .

Coherent double-color interference microscope for traceable optical surface metrology

NASA Astrophysics Data System (ADS)

Malinovski, I.; França, R. S.; Bessa, M. S.; Silva, C. R.; Couceiro, I. B.

2016-06-01

Interference microscopy is an important field of dimensional surface metrology because it provides direct traceability of the measurements to the SI base unit definition of the metre. With a typical measurement range from micrometres to nanometres interference microscopy (IM) covers the gap between classic metrology and nanometrology, providing continuous transfer of dimensional metrology into new areas of nanoscience and nanotechnology. Therefore IM is considered to be an indispensable tool for traceable transfer of the metre unit to different instruments. We report here the metrological study of an absolute Linnik interference microscope (IM) based on two frequency stabilized lasers. The design permits the flexible use of both lasers for measurements depending on the demand of the concrete measurement task. By principle of operation IM is combination of imaging and phase-shifting interferometry (PSI). The traceability is provided by the wavelength reference, that is, a He-Ne 633 nm stabilized laser. The second laser source, that is, a Blue-Green 488 nm grating stabilized laser diode, is used for improvements of resolution, and also for resolving integer fringe discontinuities on sharp features of the surface. The IM was optimized for surface height metrology. We have performed the study of the systematic effects of the measurements. This study allowed us to improve the hardware and software of IM and to find corrections for main systematic errors. The IM is purposed for 1D to 3D height metrology and surface topography in an extended range from nanometres to micrometres. The advantages and disadvantages of the design and developed methods are discussed.

Solution-mediated cladding doping of commercial polymer optical fibers

NASA Astrophysics Data System (ADS)

Stajanca, Pavol; Topolniak, Ievgeniia; Pötschke, Samuel; Krebber, Katerina

2018-03-01

Solution doping of commercial polymethyl methacrylate (PMMA) polymer optical fibers (POFs) is presented as a novel approach for preparation of custom cladding-doped POFs (CD-POFs). The presented method is based on a solution-mediated diffusion of dopant molecules into the fiber cladding upon soaking of POFs in a methanol-dopant solution. The method was tested on three different commercial POFs using Rhodamine B as a fluorescent dopant. The dynamics of the diffusion process was studied in order to optimize the doping procedure in terms of selection of the most suitable POF, doping time and conditions. Using the optimized procedure, longer segment of fluorescent CD-POF was prepared and its performance was characterized. Fiber's potential for sensing and illumination applications was demonstrated and discussed. The proposed method represents a simple and cheap way for fabrication of custom, short to medium length CD-POFs with various dopants.

First 65nm tape-out using inverse lithography technology (ILT)

NASA Astrophysics Data System (ADS)

Hung, Chi-Yuan; Zhang, Bin; Tang, Deming; Guo, Eric; Pang, Linyong; Liu, Yong; Moore, Andrew; Wang, Kechang

2005-11-01

This paper presents SMIC's first 65nm tape out results, in particularly, using ILT. ILT mathematically determines the mask features that produce the desired on-wafer results with best wafer pattern fidelity, largest process window or both. SMIC applied it to its first 65nm tape-out to study ILT performance and benefits for deep sub-wavelength lithography. SMIC selected 3 SRAM designs as the first test case, because SRAM bit-cells contain features which are challenging lithographically. Mask patterns generated from both conventional OPC and ILT were placed on the mask side-by-side. Mask manufacturability (including fracturing, writing time, inspection, and metrology) and wafer print performance of ILT were studied. The results demonstrated that ILT achieved better CD accuracy, produced substantially larger process window than conventional OPC, and met SMIC's 65nm process window requirements.

Verification and extension of the MBL technique for photo resist pattern shape measurement

NASA Astrophysics Data System (ADS)

Isawa, Miki; Tanaka, Maki; Kazumi, Hideyuki; Shishido, Chie; Hamamatsu, Akira; Hasegawa, Norio; De Bisschop, Peter; Laidler, David; Leray, Philippe; Cheng, Shaunee

2011-03-01

In order to achieve pattern shape measurement with CD-SEM, the Model Based Library (MBL) technique is in the process of development. In this study, several libraries which consisted by double trapezoid model placed in optimum layout, were used to measure the various layout patterns. In order to verify the accuracy of the MBL photoresist pattern shape measurement, CDAFM measurements were carried out as a reference metrology. Both results were compared to each other, and we confirmed that there is a linear correlation between them. After that, to expand the application field of the MBL technique, it was applied to end-of-line (EOL) shape measurement to show the capability. Finally, we confirmed the possibility that the MBL could be applied to more local area shape measurement like hot-spot analysis.

Adsorption of Cd(II) Metal Ion on Adsorbent beads from Biomass Saccharomycess cereviceae - Chitosan

NASA Astrophysics Data System (ADS)

Hasri; Mudasir

2018-01-01

The adsorbent beads that was preparation from Saccharomycess cereviceae culture strain FN CC 3012 and shrimp shells waste and its application for adsorption of Cd (II) metal ion has been studied. The study start with combination of Saccharomycess cereviceae biomass to chitosan (Sc-Chi), contact time, pH of solution and initial concentration of cations. Total Cd(II) metal ion adsorbed was calculated from the difference of metal ion concentration before and after adsorption by AAS. The results showed that optimum condition for adsorption of Cd(II) ions by Sc-Chi beads was achieved with solution pH of 4, contact time of 60 minutes and initial concentration adsorption 100mg/L. The hydroxyl (-OH) and amino (-NH2) functional groups were believed to be responsible for the adsorption of Cd(II) ions.

Laser-induced breakdown spectroscopic detection of trace level heavy metal in solutions on a laser-pretreated metallic target.

PubMed

Niu, Sheng; Zheng, Lijuan; Khan, Abdul Qayyum; Feng, Guang; Zeng, Heping

2018-03-01

A fast and sensitive analysis for trace level heavy metals in aqueous solution was realized by using an improved laser induced breakdown spectroscopy (LIBS) methodology. Solutions containing heavy metal elements, Ni, Cr, and Cd, were concentrated in a laser-pretreated area (25 × 20mm 2 ) of a polished aluminum target surface, wherein pretreated grooves enabled homogeneous distribution of the metallic solutions in the well-defined area, and laser ablation of the aluminum target produced unique plasma excitation of various metallic ions. For 1-mL solutions deposited, we obtained an analytical precision of about 7% relative standard deviation (RSD), and limits of detection (LODs) of 22, 19, and 184μg/L for Ni, Cr, and Cd, respectively. Moreover, the laser-pretreated metallic microstructure allowed more solution deposited with the help of a hot plate, which supported improvement of LODs to sub-μg/L level for Cr and Ni and μg/L level for Cd with about 20-mL solution engaged in the enrichment processes. The applicability of the proposed methodology was validated on certified reference materials and real river water. Copyright © 2017 Elsevier B.V. All rights reserved.

The EDTA effect on phytoextraction of single and combined metals-contaminated soils using rainbow pink (Dianthus chinensis).

PubMed

Lai, Hung-Yu; Chen, Zueng-Sang

2005-08-01

Rainbow pink (Dianthus chinensis), a potential phytoextraction plant, can accumulate high concentrations of Cd from metal-contaminated soils. The soils used in this study were artificially added with different metals including (1) CK: original soil, (2) Cd-treated soil: 10 mg Cd kg(-1), (3) Zn-treated soil: 100 mg Zn kg(-1), (4) Pb-treated soil: 1000 mg Pb kg(-1), (5) Cd-Zn-treated soil: 10 mg Cd kg(-1) and 100 mg Zn kg(-1), (6) Cd-Pb-treated soil: 10 mg Cd kg(-1) and 1000 mg Pb kg(-1), (7) Zn-Pb-treated soil: 100 mg Zn kg(-1) and 1000 mg Pb kg(-1), and (8) Cd-Zn-Pb-treated soil: 10 mg Cd kg(-1), 100 mg Zn kg(-1), and 1000 mg Pb kg(-1). Three concentrations of 2Na-EDTA solutions (0 (control), 2, and 5 mmol kg(-1) soil) were added to the different metals-treated soils to study the influence of applied EDTA on single and combined metals-contaminated soils phytoextraction using rainbow pink. The results showed that the Cd, Zn, Pb, Fe, or Mn concentrations in different metals-treated soil solutions significantly increased after applying 5 mmol EDTA kg(-1) (p<0.05). The metal concentrations in different metals-treated soils extracted by deionized water also significantly increased after applying 5 mmol EDTA kg(-1) (p<0.05). Because of the high extraction capacity of both 0.005 M DTPA (pH 5.3) and 0.05 M EDTA (pH 7.0), applying EDTA did not significantly increase the Cd, Zn, or Pb concentration in both extracts for most of the treatments. Applying EDTA solutions can significantly increase the Cd and Pb concentrations in the shoots of rainbow pink (p<0.05). However, this was not statistically significant for Zn because of the low Zn concentration added into the contaminated soils. The results from this study indicate that applying 5 mmol EDTA kg(-1) can significantly increase the Cd, Zn, or Pb concentrations both in the soil solution or extracted using deionized water in single or combined metals-contaminated soils, thus increasing the accumulated metals concentrations in rainbow pink shoots. The proposed method worked especially well for Pb (p<0.05). The application of 2 mmol EDTA kg(-1) might too low to enhance the phytoextraction effect when used in silty clay soils.

Equilibrium, Kinetic, and Thermodynamic Studies on the Adsorption of Cadmium from Aqueous Solution by Modified Biomass Ash

PubMed Central

Zheng, Xuebo; Cui, Hongbiao; Zhu, Zhenqiu; Liang, Jiani

2017-01-01

Natural biomass ash of agricultural residuals was collected from a power plant and modified with hexagonal mesoporous silica and functionalized with 3-aminopropyltriethoxysilane. The physicochemical and morphological properties of the biomass ash were analyzed by ICP-OES, SEM, TEM-EDS, FTIR, and BET analysis. The adsorption behavior of the modified product for Cd2+ in aqueous solution was studied as a function of pH, initial metal concentration, equilibrium time, and temperature. Results showed that the specific surface area of the modified product was 9 times that of the natural biomass ash. The modified biomass ash exhibited high affinity for Cd2+ and its adsorption capacity increased sharply with increasing pH from 4.0 to 6.0. The maximum adsorption capacity was 23.95 mg/g in a pH 5 solution with an initial metal concentration of 50 mg/L and a contact time of 90 min. The adsorption of Cd2+ onto the modified biomass ash was well fitted to the Langmuir model and it followed pseudo-second-order kinetics. Thermodynamic analysis results showed that the adsorption of Cd2+ was spontaneous and endothermic in nature. The results suggest that the modified biomass ash is promising for use as an inexpensive and effective adsorbent for Cd2+ removal from aqueous solution. PMID:28348509

Two Approaches to Calibration in Metrology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campanelli, Mark

2014-04-01

Inferring mathematical relationships with quantified uncertainty from measurement data is common to computational science and metrology. Sufficient knowledge of measurement process noise enables Bayesian inference. Otherwise, an alternative approach is required, here termed compartmentalized inference, because collection of uncertain data and model inference occur independently. Bayesian parameterized model inference is compared to a Bayesian-compatible compartmentalized approach for ISO-GUM compliant calibration problems in renewable energy metrology. In either approach, model evidence can help reduce model discrepancy.

Dynamic metrology and data processing for precision freeform optics fabrication and testing

NASA Astrophysics Data System (ADS)

Aftab, Maham; Trumper, Isaac; Huang, Lei; Choi, Heejoo; Zhao, Wenchuan; Graves, Logan; Oh, Chang Jin; Kim, Dae Wook

2017-06-01

Dynamic metrology holds the key to overcoming several challenging limitations of conventional optical metrology, especially with regards to precision freeform optical elements. We present two dynamic metrology systems: 1) adaptive interferometric null testing; and 2) instantaneous phase shifting deflectometry, along with an overview of a gradient data processing and surface reconstruction technique. The adaptive null testing method, utilizing a deformable mirror, adopts a stochastic parallel gradient descent search algorithm in order to dynamically create a null testing condition for unknown freeform optics. The single-shot deflectometry system implemented on an iPhone uses a multiplexed display pattern to enable dynamic measurements of time-varying optical components or optics in vibration. Experimental data, measurement accuracy / precision, and data processing algorithms are discussed.

Effects of the microbial siderophore DFO-B on Pb and Cd speciation in aqueous solution.

PubMed

Mishra, Bhoopesh; Haack, Elizabeth A; Maurice, Patricia A; Bunker, Bruce A

2009-01-01

This study investigates the complexation environments of aqueous Pb and Cd in the presence of the trihydroxamate microbial siderophore, desferrioxamine-B (DFO-B) as a function of pH. Complexation of aqueous Pb and Cd with DFO-B was predicted using equilibrium speciation calculation. Synchrotron-based X-ray absorption fine structure (XAFS) spectroscopy at Pb L(III) edge and Cd K edge was used to characterize Pb and Cd-DFO-B complexes at pH values predicted to best represent each of the metal-siderophore complexes. Pb was not found to be complexed measurably by DFO-B at pH 3.0, but was complexed by all three hydroxamate groups to form a totally "caged" hexadentate structure at pH 7.5-9.0. At the intermediate pH value (pH 4.8), a mixture of Pb-DFOB complexes involving binding of the metal through one and two hydroxamate groups was observed. Cd, on the other hand, remained as hydrated Cd2+ at pH 5.0, occurred as a mixture of Cd-DFOB and inorganic species at pH 8.0, and was bound by three hydroxamate groups from DFO-B at pH 9.0. Overall, the solution species observed with EXAFS were consistent with those predicted thermodynamically. However, Pb speciation at higher pH values differed from that predicted and suggests that published constants underestimate the binding constant for complexation of Pb with all three hydroxamate groups of the DFO-B ligand. This molecular-level understanding of metal-siderophore solution coordination provides physical evidence for complexes of Pb and Cd with DFO-B, and is an important first step toward understanding processes at the microbial- and/or mineral-water interface in the presence of siderophores.

Diffusion Limitations in Root Uptake of Cadmium and Zinc, But Not Nickel, and Resulting Bias in the Michaelis Constant1[W][OA

PubMed Central

Degryse, Fien; Shahbazi, Afsaneh; Verheyen, Liesbeth; Smolders, Erik

2012-01-01

It has long been recognized that diffusive boundary layers affect the determination of active transport parameters, but this has been largely overlooked in plant physiological research. We studied the short-term uptake of cadmium (Cd), zinc (Zn), and nickel (Ni) by spinach (Spinacia oleracea) and tomato (Lycopersicon esculentum) in solutions with or without metal complexes. At same free ion concentration, the presence of complexes, which enhance the diffusion flux, increased the uptake of Cd and Zn, whereas Ni uptake was unaffected. Competition effects of protons on Cd and Zn uptake were observed only at a very large degree of buffering, while competition of magnesium ions on Ni uptake was observed even in unbuffered solutions. These results strongly suggest that uptake of Cd and Zn is limited by diffusion of the free ion to the roots, except at very high degree of solution buffering, whereas Ni uptake is generally internalization limited. All results could be well described by a model that combined a diffusion equation with a competitive Michaelis-Menten equation. Direct uptake of the complex was estimated to be a major contribution only at millimolar concentrations of the complex or at very large ratios of complex to free ion concentration. The true Km for uptake of Cd2+ and Zn2+ was estimated at <5 nm, three orders of magnitude smaller than the Km measured in unbuffered solutions. Published Michaelis constants for plant uptake of Cd and Zn likely strongly overestimate physiological ones and should not be interpreted as an indicator of transporter affinity. PMID:22864584

Screening hydroxyapatite for cadmium and lead immobilization in aqueous solution and contaminated soil: The role of surface area.

PubMed

Li, Hongying; Guo, Xisheng; Ye, Xinxin

2017-02-01

Hydroxyapatite (HAP) has been widely used to immobilize many cationic metals in water and soils. The specific reason why an increase in the surface area of HAP enhances cadmium (Cd) uptake, but has no effect on lead (Pb) uptake, is not clear. The aim of this study was to determine the factors causing the differences in sorption behavior between Cd and Pb by evaluating HAPs with different surface areas. We synthesized HAPs with two different surface areas, which were characterized by X-ray diffraction, N 2 adsorption, and scanning electron microscopy, and then evaluated them as sorbents for Cd and Pb removal by testing in single and binary systems. The sorption capacity of large surface area HAP (1.85mmol/g) for Cd in the single-metal system was higher than that of small surface area HAP (0.64mmol/g), but there were no differences between single- and binary-metal solutions containing Pb. After the Cd experiments, the HAP retained a stable structure and intact morphology, which promotes the accessibility of reactive sites for Cd. However, a newly formed precipitate covered the surface and blocked the channels in the presence of Pb, which reduced the number of potential adsorption sites on HAP for Cd and Pb. Remediation experiments using Cd- and Pb-contaminated soil produced similar results to the solution tests. These results indicate that alterations of the structure and morphology during the reaction is an important factor influencing metal sorption to HAP. Copyright © 2016. Published by Elsevier B.V.

Preparation and Characterization of Biochars from Eichornia crassipes for Cadmium Removal in Aqueous Solutions.

PubMed

Li, Feng; Shen, Kaixuan; Long, Xiaolin; Wen, Jiasheng; Xie, Xiaojie; Zeng, Xiangyun; Liang, Yanyan; Wei, Yansha; Lin, Zefeng; Huang, Wenrou; Zhong, Ruida

2016-01-01

The study investigated the preparation and characterization of biochars from water hyacinth at 300°C to 700°C for cadmium (Cd) removal from aqueous solutions. The adsorption process was dominated by oxygen-containing functional groups with irregular surfaces via esterification reactions. Furthermore, the mineral components in the biochars also contributed to Cd absorption through precipitation. Parameters such as the effects of solution pH, contact time, and initial concentration were studied. The optimum pH value was observed at 5.0, in which nearly 90% of Cd was removed. The maximum Cd adsorption capacities based on the Langmuir isotherm were calculated at 49.837, 36.899, and 25.826 mg g(-1). The adsorption processes of the biochars followed the pseudo-second-order kinetics, with the equilibrium achieved around 5 h. The biochar from E. crassipes is a promising adsorbent for the treatment of wastewater, which can in turn convert one environmental problem to a new cleaning Technology.

Preparation and Characterization of Biochars from Eichornia crassipes for Cadmium Removal in Aqueous Solutions

PubMed Central

Li, Feng; Shen, Kaixuan; Long, Xiaolin; Wen, Jiasheng; Xie, Xiaojie; Zeng, Xiangyun; Liang, Yanyan; Wei, Yansha; Lin, Zefeng; Huang, Wenrou; Zhong, Ruida

2016-01-01

The study investigated the preparation and characterization of biochars from water hyacinth at 300°C to 700°C for cadmium (Cd) removal from aqueous solutions. The adsorption process was dominated by oxygen-containing functional groups with irregular surfaces via esterification reactions. Furthermore, the mineral components in the biochars also contributed to Cd absorption through precipitation. Parameters such as the effects of solution pH, contact time, and initial concentration were studied. The optimum pH value was observed at 5.0, in which nearly 90% of Cd was removed. The maximum Cd adsorption capacities based on the Langmuir isotherm were calculated at 49.837, 36.899, and 25.826 mg g−1. The adsorption processes of the biochars followed the pseudo-second-order kinetics, with the equilibrium achieved around 5 h. The biochar from E. crassipes is a promising adsorbent for the treatment of wastewater, which can in turn convert one environmental problem to a new cleaning Technology. PMID:26882239

Stability of natamycin and its cyclodextrin inclusion complexes in aqueous solution.

PubMed

Koontz, John L; Marcy, Joseph E; Barbeau, William E; Duncan, Susan E

2003-11-19

Aqueous solutions of natamycin and its beta-cyclodextrin (beta-CD), hydroxypropyl beta-cyclodextrin, and gamma-cyclodextrin (gamma-CD) inclusion complexes were completely degraded after 24 h of exposure to 1000 lx fluorescent lighting at 4 degrees C. After 14 days of storage in darkness at 4 degrees C, 92.2% of natamycin remained in active form. The natamycin:beta-CD complex and natamycin:gamma-CD complex were significantly more stable (p < 0.05) than natamycin in its free state in aqueous solutions stored in darkness at 4 degrees C. Clear poly(ethylene terephthalate) packaging with a UV light absorber allowed 85.0% of natamycin to remain after 14 days of storage under 1000 lx fluorescent lighting at 4 degrees C. Natamycin:cyclodextrin complexes can be dissociated for analysis in methanol/water/acetic acid, 60:40:5, v/v/v. Natamycin and its complexes in dissociated form were quantified by reverse phase HPLC with detection by photodiode array at 304 nm.

A Diffusive Gradient-in-Thin-Film Technique for Evaluation of the Bioavailability of Cd in Soil Contaminated with Cd and Pb

PubMed Central

Wang, Peifang; Wang, Teng; Yao, Yu; Wang, Chao; Liu, Cui; Yuan, Ye

2016-01-01

Management of heavy metal contamination requires accurate information about the distribution of bioavailable fractions, and about exchange between the solid and solution phases. In this study, we employed diffusive gradients in thin-films (DGT) and traditional chemical extraction methods (soil solution, HOAc, EDTA, CaCl2, and NaOAc) to determine the Cd bioavailability in Cd-contaminated soil with the addition of Pb. Two typical terrestrial species (wheat, Bainong AK58; maize, Zhengdan 958) were selected as the accumulation plants. The results showed that the added Pb may enhance the efficiency of Cd phytoextraction which is indicated by the increasing concentration of Cd accumulating in the plant tissues. The DGT-measured Cd concentrations and all the selected traditional extractants measured Cd concentrations all increased with increasing concentration of the addition Pb which were similar to the change trends of the accumulated Cd concentrations in plant tissues. Moreover, the Pearson regression coefficients between the different indicators obtained Cd concentrations and plants uptake Cd concentrations were further indicated significant correlations (p < 0.01). However, the values of Pearson regression coefficients showed the merits of DGT, CaCl2, and Csol over the other three methods. Consequently, the in situ measurement of DGT and the ex situ traditional methods could all reflect the inhibition effects between Cd and Pb. Due to the feature of dynamic measurements of DGT, it could be a robust tool to predict Cd bioavaiability in complex contaminated soil. PMID:27271644

Status of CdS/CdTe solar cell research at NREL

NASA Astrophysics Data System (ADS)

Ramanathan, K.; Dhere, R. G.; Coutts, T. J.; Chu, T.; Chu, S.

1992-12-01

We report on the deposition of thin cadmium sulfide (CdS) layers from aqueous solutions and their optical properties. CdS layers have been deposited on soda lime glass, tin oxide coated glass and copper indium diselenide (CuInSe2) thin films. A systematic increase in the absorption is found to occur with increasing concentration of the buffer salt used in the bath. CdS/CdTe thin film solar cells have been fabricated by close spaced sublimation of CdTe, yielding 11.3% devices.

A suitable deposition method of CdS for high performance CdS-sensitized ZnO electrodes: Sequential chemical bath deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Haining; Li, Weiping; Liu, Huicong

2010-07-15

A suitable deposition method of CdS is necessary for the high performance CdS-sensitized ZnO electrodes. In this paper, chemical bath deposition (CBD) and sequential chemical bath deposition (S-CBD) methods were used to deposit CdS on ZnO mesoporous films for ZnO/CdS electrodes. The analysis results of XRD patterns and UV-vis spectroscopy indicated that CBD deposition method leaded to the dissolving of ZnO mesoporous films in deposition solution and thickness reduction of ZnO/CdS electrodes. Absorption in visible region by the ZnO/CdS electrodes with CdS deposition by S-CBD was enhanced as deposition cycles increased due to the stability of ZnO mesoporous films inmore » the S-CBD deposition solutions. The results of photocurrent-voltage (I-V) measurement showed that the performance of ZnO/CdS electrodes with CdS deposition by CBD first increased and then decreased as deposition time increased, and the greatest short-circuit current (J{sub sc}) was obtained at the deposition time of 4 min. The performance of ZnO/CdS electrodes with CdS deposition by S-CBD increased as deposition cycles increased, and both open-circuit voltage (V{sub oc}) and J{sub sc} were greater than those electrodes with CdS deposition by CBD when the deposition cycles of S-CBD were 10 or greater. These results indicated that S-CBD is a more suitable method for high performance ZnO/CdS electrodes. (author)« less

Leaching of Metal Pollutants from Four Well Casings Used for Ground-Water Monitoring

DTIC Science & Technology

1989-09-01

Atomic Spectroscopy, 4:126-128. 10 APPENDIX A : LEVELS OF CD, PB, CR, BA AND CU DETERMINED IN GROUND-WATER SOLUTIONS (MG/L). Time Pqle R:ph’itc (day1s...7 Conclusion ................................................... 9 Literature cited ................................................ 9 Appendix A ... Levels of Cd, Pb, Cr, Ba and Cu determined in ground-water solutions .................................................. 11 ILLUSTRATIONS Figure 1. Ground

Multimedia Language Learning Courseware: A Design Solution to the Production of a Series of CD-ROMs.

ERIC Educational Resources Information Center

Brett, P. A.; Nash, M.

1999-01-01

Discusses multimedia software and describes the production and the learning rationale of a series of six multimedia CD-ROMs that develop the listening skills of learners of Business English. Describes problems of cost, time, and quality in producing multiple courseware and explains the programming solution which gives control to subject experts.…

Role of Precursor-Conversion Chemistry in the Crystal-Phase Control of Catalytically Grown Colloidal Semiconductor Quantum Wires.

PubMed

Wang, Fudong; Buhro, William E

2017-12-26

Crystal-phase control is one of the most challenging problems in nanowire growth. We demonstrate that, in the solution-phase catalyzed growth of colloidal cadmium telluride (CdTe) quantum wires (QWs), the crystal phase can be controlled by manipulating the reaction chemistry of the Cd precursors and tri-n-octylphosphine telluride (TOPTe) to favor the production of either a CdTe solute or Te, which consequently determines the composition and (liquid or solid) state of the Bi x Cd y Te z catalyst nanoparticles. Growth of single-phase (e.g., wurtzite) QWs is achieved only from solid catalysts (y ≪ z) that enable the solution-solid-solid growth of the QWs, whereas the liquid catalysts (y ≈ z) fulfill the solution-liquid-solid growth of the polytypic QWs. Factors that affect the precursor-conversion chemistry are systematically accounted for, which are correlated with a kinetic study of the composition and state of the catalyst nanoparticles to understand the mechanism. This work reveals the role of the precursor-reaction chemistry in the crystal-phase control of catalytically grown colloidal QWs, opening the possibility of growing phase-pure QWs of other compositions.

Networking CD-ROMs: A Tutorial Introduction.

ERIC Educational Resources Information Center

Perone, Karen

1996-01-01

Provides an introduction to CD-ROM networking. Highlights include LAN (local area network) architectures for CD-ROM networks, peer-to-peer networks, shared file and dedicated file servers, commercial software/vendor solutions, problems, multiple hardware platforms, and multimedia. Six figures illustrate network architectures and a sidebar contains…

Thermophilic Geobacillus galactosidasius sp. nov. loaded γ-Fe2O3 magnetic nanoparticle for the preconcentrations of Pb and Cd.

PubMed

Özdemir, Sadin; Kilinç, Ersin; Okumuş, Veysi; Poli, Annarita; Nicolaus, Barbara; Romano, Ida

2016-02-01

Thermophilic bacteria, Geobacillus galactosidasius sp nov. was loaded on γ-Fe2O3 magnetic nanoparticle for the preconcentrations of Pb and Cd by solid phase extraction before ICP-OES. pH and flow rate of the solution, amounts of biosorbent and magnetic nanoparticle, volume of sample solution, effects of the possible interferic ions were investigated in details. Linear calibration curves were constructed in the concentration ranges of 1.0-60ngmL(-1) for Pb and Cd. The RSDs of the method were lower than 2.8% for Pb and 3.8% for Cd. Certified and standard reference samples of fortified water, wastewater, poplar leaves, and simulated fresh water were used to accurate the method. LOD values were found as 0.07 and 0.06ngmL(-1) respectively for Pb and Cd. The biosorption capacities were found as 34.3mgg(-1) for Pb and 37.1mgg(-1) for Cd. Pb and Cd concentrations in foods were determined. Surface microstructure was investigated by SEM-EDX. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of Te and TeO 2 on CdZnTe Nuclear Detectors Treated with Hydrogen Bromide and Ammonium-Based Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drabo, Mebougna L.; Egarievwe, Stephen U.; Okwechime, Ifechukwude O.

Surface defects caused during cutting and polishing in the fabrication of cadmium zinc telluride (CdZnTe) nuclear detectors limit their spectral performance. Chemical treatments are often used to remove surface damages and defects. In this paper, we present the analysis of Te and TeO 2 species on the surfaces of CdZnTe nuclear detectors treated with hydrogen bromide and ammonium-based solutions. The CdZnTe wafers were chemo-mechanically polished in a mixture of hydrogen bromide in hydrogen peroxide and ethylene glycol, followed by a chemical passivation in a mixture of ammonium fluoride and hydrogen peroxide solution. X-ray photoelectron spectroscopy showed significant conversion of Temore » to TeO 2, thus producing a more chemically stable surface. The resistivity of the CdZnTe samples is in the order of 1010 ohms-cm. The current for a given applied voltage increased following the passivation and decreased after a 3-hour period. Results from spectral response measurements showed that the 59.5-keV gamma-peak of Am-241 was stable under the same channel for the surface treatment processes.« less

Analysis of Te and TeO 2 on CdZnTe Nuclear Detectors Treated with Hydrogen Bromide and Ammonium-Based Solutions

DOE PAGES

Drabo, Mebougna L.; Egarievwe, Stephen U.; Okwechime, Ifechukwude O.; ...

2017-04-30

Surface defects caused during cutting and polishing in the fabrication of cadmium zinc telluride (CdZnTe) nuclear detectors limit their spectral performance. Chemical treatments are often used to remove surface damages and defects. In this paper, we present the analysis of Te and TeO 2 species on the surfaces of CdZnTe nuclear detectors treated with hydrogen bromide and ammonium-based solutions. The CdZnTe wafers were chemo-mechanically polished in a mixture of hydrogen bromide in hydrogen peroxide and ethylene glycol, followed by a chemical passivation in a mixture of ammonium fluoride and hydrogen peroxide solution. X-ray photoelectron spectroscopy showed significant conversion of Temore » to TeO 2, thus producing a more chemically stable surface. The resistivity of the CdZnTe samples is in the order of 1010 ohms-cm. The current for a given applied voltage increased following the passivation and decreased after a 3-hour period. Results from spectral response measurements showed that the 59.5-keV gamma-peak of Am-241 was stable under the same channel for the surface treatment processes.« less

Precision process calibration and CD predictions for low-k1 lithography

NASA Astrophysics Data System (ADS)

Chen, Ting; Park, Sangbong; Berger, Gabriel; Coskun, Tamer H.; de Vocht, Joep; Chen, Fung; Yu, Linda; Hsu, Stephen; van den Broeke, Doug; Socha, Robert; Park, Jungchul; Gronlund, Keith; Davis, Todd; Plachecki, Vince; Harris, Tom; Hansen, Steve; Lambson, Chuck

2005-06-01

Leading resist calibration for sub-0.3 k1 lithography demands accuracy <2nm for CD through pitch. An accurately calibrated resist process is the prerequisite for establishing production-worthy manufacturing under extreme low k1. From an integrated imaging point of view, the following key components must be simultaneously considered during the calibration - high numerical aperture (NA>0.8) imaging characteristics, customized illuminations (measured vs. modeled pupil profiles), resolution enhancement technology (RET) mask with OPC, reticle metrology, and resist thin film substrate. For imaging at NA approaching unity, polarized illumination can impact significantly the contrast formation in the resist film stack, and therefore it is an important factor to consider in the CD-based resist calibration. For aggressive DRAM memory core designs at k1<0.3, pattern-specific illumination optimization has proven to be critical for achieving the required imaging performance. Various optimization techniques from source profile optimization with fixed mask design to the combined source and mask optimization have been considered for customer designs and available imaging capabilities. For successful low-k1 process development, verification of the optimization results can only be made with a sufficiently tunable resist model that can predicate the wafer printing accurately under various optimized process settings. We have developed, for resist patterning under aggressive low-k1 conditions, a novel 3D diffusion model equipped with double-Gaussian convolution in each dimension. Resist calibration with the new diffusion model has demonstrated a fitness and CD predication accuracy that rival or outperform the traditional 3D physical resist models. In this work, we describe our empirical approach to achieving the nm-scale precision for advanced lithography process calibrations, using either measured 1D CD through-pitch or 2D memory core patterns. We show that for ArF imaging, the current resist development and diffusion modeling can readily achieve ~1-2nm max CD errors for common 1D through-pitch and aggressive 2D memory core resist patterns. Sensitivities of the calibrated models to various process parameters are analyzed, including the comparison between the measured and modeled (Gaussian or GRAIL) pupil profiles. We also report our preliminary calibration results under selected polarized illumination conditions.

Virtual overlay metrology for fault detection supported with integrated metrology and machine learning

NASA Astrophysics Data System (ADS)

Lee, Hong-Goo; Schmitt-Weaver, Emil; Kim, Min-Suk; Han, Sang-Jun; Kim, Myoung-Soo; Kwon, Won-Taik; Park, Sung-Ki; Ryan, Kevin; Theeuwes, Thomas; Sun, Kyu-Tae; Lim, Young-Wan; Slotboom, Daan; Kubis, Michael; Staecker, Jens

2015-03-01

While semiconductor manufacturing moves toward the 7nm node for logic and 15nm node for memory, an increased emphasis has been placed on reducing the influence known contributors have toward the on product overlay budget. With a machine learning technique known as function approximation, we use a neural network to gain insight to how known contributors, such as those collected with scanner metrology, influence the on product overlay budget. The result is a sufficiently trained function that can approximate overlay for all wafers exposed with the lithography system. As a real world application, inline metrology can be used to measure overlay for a few wafers while using the trained function to approximate overlay vector maps for the entire lot of wafers. With the approximated overlay vector maps for all wafers coming off the track, a process engineer can redirect wafers or lots with overlay signatures outside the standard population to offline metrology for excursion validation. With this added flexibility, engineers will be given more opportunities to catch wafers that need to be reworked, resulting in improved yield. The quality of the derived corrections from measured overlay metrology feedback can be improved using the approximated overlay to trigger, which wafers should or shouldn't be, measured inline. As a development or integration engineer the approximated overlay can be used to gain insight into lots and wafers used for design of experiments (DOE) troubleshooting. In this paper we will present the results of a case study that follows the machine learning function approximation approach to data analysis, with production overlay measured on an inline metrology system at SK hynix.

Effect of metrology time delay on overlay APC

NASA Astrophysics Data System (ADS)

Carlson, Alan; DiBiase, Debra

2002-07-01

The run-to-run control strategy of lithography APC is primarily composed of a feedback loop as shown in the diagram below. It is known that the insertion of a time delay in a feedback loop can cause degradation in control performance and could even cause a stable system to become unstable, if the time delay becomes sufficiently large. Many proponents of integrated metrology methods have cited the damage caused by metrology time delays as the primary justification for moving from a stand-alone to integrated metrology. While there is little dispute over the qualitative form of this argument, there has been very light published about the quantitative effects under real fab conditions - precisely how much control is lost due to these time delays. Another issue regarding time delays is that the length of these delays is not typically fixed - they vary from lot to lot and in some cases this variance can be large - from one hour on the short side to over 32 hours on the long side. Concern has been expressed that the variability in metrology time delays can cause undesirable dynamics in feedback loops that make it difficult to optimize feedback filters and gains and at worst could drive a system unstable. By using data from numerous fabs, spanning many sizes and styles of operation, we have conducted a quantitative study of the time delay effect on overlay run- to-run control. Our analysis resulted in the following conclusions: (1) There is a significant and material relationship between metrology time delay and overlay control under a variety of real world production conditions. (2) The run-to-run controller can be configured to minimize sensitivity to time delay variations. (3) The value of moving to integrated metrology can be quantified.

Absolute metrology for space interferometers

NASA Astrophysics Data System (ADS)

Salvadé, Yves; Courteville, Alain; Dändliker, René

2017-11-01

The crucial issue of space-based interferometers is the laser interferometric metrology systems to monitor with very high accuracy optical path differences. Although classical high-resolution laser interferometers using a single wavelength are well developed, this type of incremental interferometer has a severe drawback: any interruption of the interferometer signal results in the loss of the zero reference, which requires a new calibration, starting at zero optical path difference. We propose in this paper an absolute metrology system based on multiplewavelength interferometry.

Lowering the environmental impact of high-kappa/ metal gate stack surface preparation processes

NASA Astrophysics Data System (ADS)

Zamani, Davoud

ABSTRACT Hafnium based oxides and silicates are promising high-κ dielectrics to replace SiO2 as gate material for state-of-the-art semiconductor devices. However, integrating these new high-κ materials into the existing complementary metal-oxide semiconductor (CMOS) process remains a challenge. One particular area of concern is the use of large amounts of HF during wet etching of hafnium based oxides and silicates. The patterning of thin films of these materials is accomplished by wet etching in HF solutions. The use of HF allows dissolution of hafnium as an anionic fluoride complex. Etch selectivity with respect to SiO2 is achieved by appropriately diluting the solutions and using slightly elevated temperatures. From an ESH point of view, it would be beneficial to develop methods which would lower the use of HF. The first objective of this study is to find new chemistries and developments of new wet etch methods to reduce fluoride consumption during wet etching of hafnium based high-κ materials. Another related issue with major environmental impact is the usage of large amounts of rinsing water for removal of HF in post-etch cleaning step. Both of these require a better understanding of the HF interaction with the high-κ surface during the etching, cleaning, and rinsing processes. During the rinse, the cleaning chemical is removed from the wafers. Ensuring optimal resource usage and cycle time during the rinse requires a sound understanding and quantitative description of the transport effects that dominate the removal rate of the cleaning chemicals from the surfaces. Multiple processes, such as desorption and re-adsorption, diffusion, migration and convection, all factor into the removal rate of the cleaning chemical during the rinse. Any of these processes can be the removal rate limiting process, the bottleneck of the rinse. In fact, the process limiting the removal rate generally changes as the rinse progresses, offering the opportunity to save resources. The second objective of this study is to develop new rinse methods to reduce water and energy usage during rinsing and cleaning of hafnium based high-κ materials in single wafer-cleaning tools. It is necessary to have a metrology method which can study the effect of all process parameters that affect the rinsing by knowing surface concentration of contaminants in patterned hafnium based oxides and silicate wafers. This has been achieved by the introduction of a metrology method at The University of Arizona which monitors the transport of contaminant concentrations inside micro- and nano- structures. This is the only metrology which will be able to provide surface concentration of contaminants inside hafnium based oxides and silicate micro-structures while the rinsing process is taking place. The goal of this research is to study the effect of various process parameters on rinsing of patterned hafnium based oxides and silicate wafers, and modify a metrology method for end point detection.

EDITORIAL: Metrological Aspects of Accelerator Technology and High Energy Physics Experiments

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.; Pozniak, Krzysztof T.

2007-08-01

The subject of this special feature in Measurement Science and Technology concerns measurement methods, devices and subsystems, both hardware and software aspects, applied in large experiments of high energy physics (HEP) and superconducting RF accelerator technology (SRF). These experiments concern mainly the physics of elementary particles or the building of new machines and detectors. The papers present practical examples of applied solutions in large, contemporary, international research projects such as HERA, LHC, FLASH, XFEL, ILC and others. These machines are unique in their global scale and consist of extremely dedicated apparatus. The apparatus is characterized by very large dimensions, a considerable use of resources and a high level of overall technical complexity. They possess a large number of measurement channels (ranging from thousands to over 100 million), are characterized by fast of processing of measured data and high measurement accuracies, and work in quite adverse environments. The measurement channels cooperate with a large number of different sensors of momenta, energies, trajectories of elementary particles, electron, proton and photon beam profiles, accelerating fields in resonant cavities, and many others. The provision of high quality measurement systems requires the designers to use only the most up-to-date technical solutions, measurement technologies, components and devices. Research work in these demanding fields is a natural birthplace of new measurement methods, new data processing and acquisition algorithms, complex, networked measurement system diagnostics and monitoring. These developments are taking place in both hardware and software layers. The chief intention of this special feature is that the papers represent equally some of the most current metrology research problems in HEP and SRF. The accepted papers have been divided into four topical groups: superconducting cavities (4 papers), low level RF systems (8 papers), ionizing radiation (5 papers) and HEP experiments (8 papers). The editors would like to thank cordially all the authors who accepted our invitation to present their very recent results. A number of authors of the papers in this issue are active in the 6th European Framework Research Program CARE—Coordinated Accelerators Research in Europe and ELAN—the European Linear Accelerator Network. Some authors are active in research programs of a global extent such as the LHC, ILC and GDE—the Global Design Effort for the International Linear Collider. We also would like to thank personally, as well as on behalf of all the authors, the Editorial Board of Measurement Science and Technology for accepting this very exciting field of contemporary metrology. This field seems to be really a birthplace of a host of new metrological technologies, where the driving force is the incredibly high technical requirements that must soon be fulfilled if we dream of building new accelerators for elementary particles, new biological materials and medicine alike. Special thanks are due to Professor R S Jachowicz of Warsaw University of Technology for initiating this issue and for continuous support and advice during our work.

Remediation of cadmium-contaminated paddy soils by washing with chemicals: effect of soil washing on cadmium uptake by soybean.

PubMed

Maejima, Yuji; Makino, Tomoyuki; Takano, Hiroyuki; Kamiya, Takashi; Sekiya, Naoki; Itou, Tadashi

2007-03-01

We conducted a pot experiment to evaluate the effect of soil washing with CaCl(2) on Cd absorption by two soybean cultivars. The results were as follows: (1) Soybean growth was not significantly different in washed and unwashed soils, but the seed Cd concentration for both cultivars decreased significantly, up to 25%, in the washed soils compared with the unwashed soils. (2) In the washed soils, the Cd concentration in the soil solution indicated an obviously lower value from sowing to the flowering stage; however, the change in Cd speciation was not evident in the CaCl(2)-washed soil solution. Consequently, the effect of soil washing using CaCl(2) on Cd-contaminated paddy soils can be expected to continue after a CaCl(2)-washed paddy field is converted to an upland field.

Metrology Laboratory | Energy Systems Integration Facility | NREL

Science.gov Websites

and artificial) Spectral reflectance and transmission of materials (functional check only , pyrheliometers,* pyranometers,* and pyrgeometers. The Metrology Laboratory provides National Institute of

Comparative acid-base properties of the surface of components of the CdTe-ZnS system in series of substitutional solid solutions and their analogs

NASA Astrophysics Data System (ADS)

Kirovskaya, I. A.; Kasatova, I. Yu.

2011-07-01

The acid-base properties of the surface of solid solutions and binary components of the CdTe-ZnS system are studied by hydrolytic adsorption, nonaqueous conductometric titration, mechanochemistry, IR spectroscopy, and Raman scattering spectroscopy. The strength, nature, and concentration of acid centers on the original surface and that exposed to CO are determined. The changes in acid-base properties in dependence on the composition of the system under investigation in the series of CdB6, ZnB6 analogs are studied.

Coordinate metrology of a primary surface composite panel from the Large Millimeter Telescope

NASA Astrophysics Data System (ADS)

Gale, David M.; Lucero Álvarez, Maribel; Cabrera Cuevas, Lizeth; Leon-Huerta, Andrea; Arizmendi Reyes, Edgar; Icasio Hernández, Octavio; Castro Santos, David; Hernández Ríos, Emilio; Tecuapetla Sosa, Esteban; Tzile Torres, Carlos; Viliesid Alonso, Miguel

2016-07-01

The Large Millimeter Telescope (LMT) is a single-dish fully-steerable radio telescope presently operating with a 32.5 m parabolic primary reflector, in the process of extension to 50 m. The project is managed by the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) in México, and the University of Massachusetts Amherst, USA. A laminated surface panel from the LMT primary reflector has been subjected to a surface measurement assay at Mexico's National Metrology Center (CENAM). Data obtained using a coordinate measuring machine and laser tracker owned by CENAM is compared with measurements using an identical model laser tracker and the photogrammetry technique, the latter systems owned and operated by the LMT. All measurements were performed within the controlled metrology environment at CENAM. The measurement exercise is intended to prepare the groundwork for converting this spare surface panel into a calibrated work-piece. The establishment of a calibrated work-piece provides quality assurance for metrology through measurement traceability. It also simplifies the evaluation of measurement uncertainty for coordinate metrology procedures used by the LMT project during reflector surface qualification.

The role of metrology in mediating and mobilizing the language and culture of scientific facts

NASA Astrophysics Data System (ADS)

Fisher, W. P., Jr.; Stenner, A. J.

2015-02-01

The self-conscious awareness of language and its use is arguably nowhere more intense than in metrology. The careful and deliberate coordination and alignment of shared metrological frames of reference for theory, experiment, and practical application have been characteristics of scientific culture at least since the origins of the SI units in revolutionary France. Though close attention has been focused on the logical and analytical aspects of language use in science, little concern has been shown for understanding how the social and historical aspects of everyday language may have foreshadowed and influenced the development and character of metrological language, especially relative to the inevitably partial knowledge possessed by any given stakeholder participating in the scientific enterprise. Insight in this regard may be helpful in discerning how and if an analogous role for metrology might be created in psychology and the social sciences. It may be that the success of psychology as a science will depend less on taking physics as the relevant model than on attending to the interplay of concepts, models, and social organization that make any culture effective.

Speckle-based at-wavelength metrology of X-ray mirrors with super accuracy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal, E-mail: kawal.sawhney@diamond.ac.uk

2016-05-15

X-ray active mirrors, such as bimorph and mechanically bendable mirrors, are increasingly being used on beamlines at modern synchrotron source facilities to generate either focused or “tophat” beams. As well as optical tests in the metrology lab, it is becoming increasingly important to optimise and characterise active optics under actual beamline operating conditions. Recently developed X-ray speckle-based at-wavelength metrology technique has shown great potential. The technique has been established and further developed at the Diamond Light Source and is increasingly being used to optimise active mirrors. Details of the X-ray speckle-based at-wavelength metrology technique and an example of its applicabilitymore » in characterising and optimising a micro-focusing bimorph X-ray mirror are presented. Importantly, an unprecedented angular sensitivity in the range of two nanoradians for measuring the slope error of an optical surface has been demonstrated. Such a super precision metrology technique will be beneficial to the manufacturers of polished mirrors and also in optimization of beam shaping during experiments.« less

Progress of Multi-Beam Long Trace-Profiler Development

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail; Kilaru, Kiranmayee; Merthe, Daniel J.; Kester, Thomas; McKinney, Wayne R.; Takacs, Peter Z.; Yashchuk, Valeriy V.

2012-01-01

The multi-beam long trace profiler (LTP) under development at NASA s Marshall Space Flight Center[1] is designed to increase the efficiency of metrology of replicated X-ray optics. The traditional LTP operates on a single laser beam that scans along the test surface to detect the slope errors. While capable of exceptional surface slope accuracy, the LTP single beam scanning has slow measuring speed. As metrology constitutes a significant fraction of the time spent in optics production, an increase in the efficiency of metrology helps in decreasing the cost of fabrication of the x-ray optics and in improving their quality. Metrology efficiency can be increased by replacing the single laser beam with multiple beams that can scan a section of the test surface at a single instance. The increase in speed with such a system would be almost proportional to the number of laser beams. A collaborative feasibility study has been made and specifications were fixed for a multi-beam long trace profiler. The progress made in the development of this metrology system is presented.

Geometric errors in 3D optical metrology systems

NASA Astrophysics Data System (ADS)

Harding, Kevin; Nafis, Chris

2008-08-01

The field of 3D optical metrology has seen significant growth in the commercial market in recent years. The methods of using structured light to obtain 3D range data is well documented in the literature, and continues to be an area of development in universities. However, the step between getting 3D data, and getting geometrically correct 3D data that can be used for metrology is not nearly as well developed. Mechanical metrology systems such as CMMs have long established standard means of verifying the geometric accuracies of their systems. Both local and volumentric measurments are characterized on such system using tooling balls, grid plates, and ball bars. This paper will explore the tools needed to characterize and calibrate an optical metrology system, and discuss the nature of the geometric errors often found in such systems, and suggest what may be a viable standard method of doing characterization of 3D optical systems. Finally, we will present a tradeoff analysis of ways to correct geometric errors in an optical systems considering what can be gained by hardware methods versus software corrections.

Optical Metrology for the Segmented Optics on the Constellation-X Spectroscopy X-Ray Telescope

NASA Technical Reports Server (NTRS)

Content, David; Colella, David; Fleetwood, Charles; Hadjimichael, Theo; Lehan, John; McMann, Joseph; Reid, Paul; Saha, Timo; Wright, Geraldine; Zhang, William

2004-01-01

We present the metrology requirements and metrology implementation necessary to prove out the reflector technology for the Constellation X(C-X) spectroscopy X-ray telescope (SXT). This segmented, 1.6m diameter highly nested Wolter-1 telescope presents many metrology and alignment challenges. In particular, these mirrors have a stringent imaging error budget as compared to their intrinsic stiffness; This is required for Constellation-X to have sufficient effective area with the weight requirement. This has implications for the metrology that can be used. A variety of contract and noncontact optical profiling and interferometric methods are combined to test the formed glass substrates before replication and the replicated reflector segments.The reflectors are tested both stand-alone and in-situ in an alignment tower.Some of these methods have not been used on prior X-ray telescopes and some are feasible only because of the segmented approach used on the SXT. Methods discussed include high precision coordinate measurement machines using very low force or optical probe axial interferometric profiling azimuthal circularity profiling and use of advanced null optics such as conical computer generated hologram (CGHs).

Theoferometer for the Construction of Precision Optomechanical Assemblies

NASA Technical Reports Server (NTRS)

Korzun, Ashley M.

2006-01-01

The increasing difficulty of metrology requirements on projects involving optics and the alignment of instrumentation on spacecraft has reached a turning point. Requirements as low as 0.1 arcseconds for the static, rotational alignment of components within a coordinate system cannot be met with a theodolite, the alignment tool currently in use. A "theoferometer" is an interferometer mounted on a rotation stage with degrees of freedom in azimuth and elevation for metrology and alignment applications. The success of a prototype theoferometer in approaching these metrology requirements led to a redesign stressing mechanical, optical, and software changes to increase the sensitivity and portability of the unit. This paper covers the improvements made to the first prototype theoferometer, characteristic testing, and demonstration of the redesigned theoferometer s capabilities as a "theodolite replacement" and low-uncertainty metrology tool.

Recent progress in understanding the imaging and metrology using the helium ion microscope

NASA Astrophysics Data System (ADS)

Postek, Michael T.; Vladar, Andras E.; Ming, Bin

2009-05-01

Nanotechnology is pushing imaging and measurement instrument technology to high levels of required performance. As this continues, new barriers confronting innovation in this field are encountered. Particle beam instrument resolution remains one of these barriers. A new tool for imaging and metrology for nanotechnology is the scanning Helium Ion Microscope (HIM). The HIM is a new approach to imaging and metrology for nanotechnology which may be able to push this barrier lower. As a new methodology, it is just beginning to show promise and the number of potentially advantageous applications for nanotechnology and nanometrology has yet to be fully exploited. This presentation will discuss some of the progress made at NIST in collaboration with the manufacturing community in understanding the imaging and metrology for this new technology.

Earthquakes and sea level - Space and terrestrial metrology on a changing planet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bilham, R.

1991-02-01

A review is presented of the stability and scale of crustal deformation metrology which has particular relevance to monitoring deformation associated with sea level and earthquakes. Developments in space geodesy and crustal deformation metrology in the last two decades have the potential to acquire a homogeneous global data set for monitoring relative horizontal and vertical motions of the earth's surface to within several millimeters. New tools discussed for forecasting sea level rise and damaging earthquakes include: very long baseline interferometry, satellite laser ranging, the principles of GPS geodesy, and new sea level sensors. Space geodesy permits a unified global basismore » for future metrology of the earth, and the continued availability of the GPS is currently fundamental to this unification.« less

High-precision gauging of metal rings

NASA Astrophysics Data System (ADS)

Carlin, Mats; Lillekjendlie, Bjorn

1994-11-01

Raufoss AS designs and produces air brake fittings for trucks and buses on the international market. One of the critical components in the fittings is a small, circular metal ring, which is going through 100% dimension control. This article describes a low-price, high accuracy solution developed at SINTEF Instrumentation based on image metrology and a subpixel resolution algorithm. The measurement system consists of a PC-plugg-in transputer video board, a CCD camera, telecentric optics and a machine vision strobe. We describe the measurement technique in some detail, as well as the robust statistical techniques found to be essential in the real life environment.

Thermodynamic properties of model CdTe/CdSe mixtures

DOE PAGES

van Swol, Frank; Zhou, Xiaowang W.; Challa, Sivakumar R.; ...

2015-02-20

We report on the thermodynamic properties of binary compound mixtures of model groups II–VI semiconductors. We use the recently introduced Stillinger–Weber Hamiltonian to model binary mixtures of CdTe and CdSe. We use molecular dynamics simulations to calculate the volume and enthalpy of mixing as a function of mole fraction. The lattice parameter of the mixture closely follows Vegard's law: a linear relation. This implies that the excess volume is a cubic function of mole fraction. A connection is made with hard sphere models of mixed fcc and zincblende structures. We found that the potential energy exhibits a positive deviation frommore » ideal soluton behaviour; the excess enthalpy is nearly independent of temperatures studied (300 and 533 K) and is well described by a simple cubic function of the mole fraction. Using a regular solution approach (combining non-ideal behaviour for the enthalpy with ideal solution behaviour for the entropy of mixing), we arrive at the Gibbs free energy of the mixture. The Gibbs free energy results indicate that the CdTe and CdSe mixtures exhibit phase separation. The upper consolute temperature is found to be 335 K. Finally, we provide the surface energy as a function of composition. Moreover, it roughly follows ideal solution theory, but with a negative deviation (negative excess surface energy). This indicates that alloying increases the stability, even for nano-particles.« less

Solar Radiation Research Laboratory | Energy Systems Integration Facility |

Science.gov Websites

radiation components, and has expanded its expertise to include integrated metrology, optics, electronics Acquisition Laboratory, Metrology Laboratory, Optics Laboratory, and Electronics Laboratory. Photo of a

Effects of chemo-mechanical polishing on CdZnTe X-ray and gamma-ray detectors

DOE PAGES

Egarievwe, Stephen E.; Hossain, Anwar; Okwechime, Ifechukwude O.; ...

2015-06-23

Here, mechanically polishing cadmium zinc telluride (CdZnTe) wafers for x-ray and gamma-ray detectors often is inadequate in removing surface defects caused by cutting them from the ingots. Fabrication-induced defects, such as surface roughness, dangling bonds, and nonstoichiometric surfaces, often are reduced through polishing and etching the surface. In our earlier studies of mechanical polishing with alumina powder, etching with hydrogen bromide in hydrogen peroxide solution, and chemomechanical polishing with bromine–methanol–ethylene glycol solution, we found that the chemomechanical polishing process produced the least surface leakage current. In this research, we focused on using two chemicals to chemomechanically polish CdZnTe wafers aftermore » mechanical polishing, viz. bromine–methanol–ethylene glycol (BME) solution, and hydrogen bromide (HBr) in a hydrogen peroxide and ethylene–glycol solution. We used x-ray photoelectron spectroscopy (XPS), current–voltage (I–V) measurements, and Am-241 spectral response measurements to characterize and compare the effects of each solution. The results show that the HBr-based solution produced lower leakage current than the BME solution. Results from using the same chemomechanical polishing solution on two samples confirmed that the surface treatment affects the measured bulk current (a combination of bulk and surface currents). XPS results indicate that the tellurium oxide to tellurium peak ratios for the mechanical polishing process were reduced significantly by chemomechanical polishing using the BME solution (78.9% for Te 3d 5/2O 2 and 76.7% for Te 3d 3/2O 2) compared with the HBr-based solution (27.6% for Te 3d 5/2O 2 and 35.8% for Te 3d 3/2O 2). Spectral response measurements showed that the 59.5-keV peak of Am-241 remained under the same channel number for all three CdZnTe samples. While the BME-based solution gave a better performance of 7.15% full-width at half-maximum (FWHM) compared with 7.59% FWHM for the HBr-based solution, the latter showed a smaller variation in performance of 0.39% FWHM over 7 days compared with 0.69% for the BME-based solution.« less

Consultative Committee on Ionizing Radiation: Impact on Radionuclide Metrology

PubMed Central

Karam, L.R.; Ratel, G.

2016-01-01

In response to the CIPM MRA, and to improve radioactivity measurements in the face of advancing technologies, the CIPM’s consultative committee on ionizing radiation developed a strategic approach to the realization and validation of measurement traceability for radionuclide metrology. As a consequence, measurement institutions throughout the world have devoted no small effort to establish radionuclide metrology capabilities, supported by active quality management systems and validated through prioritized participation in international comparisons, providing a varied stakeholder community with measurement confidence. PMID:26688351

Vacuum Technology Considerations For Mass Metrology

PubMed Central

Abbott, Patrick J.; Jabour, Zeina J.

2011-01-01

Vacuum weighing of mass artifacts eliminates the necessity of air buoyancy correction and its contribution to the measurement uncertainty. Vacuum weighing is also an important process in the experiments currently underway for the redefinition of the SI mass unit, the kilogram. Creating the optimum vacuum environment for mass metrology requires careful design and selection of construction materials, plumbing components, pumping, and pressure gauging technologies. We review the vacuum technology1 required for mass metrology and suggest procedures and hardware for successful and reproducible operation. PMID:26989593

Application of Ionic Liquids in Amperometric Gas Sensors.

PubMed

Gębicki, Jacek; Kloskowski, Adam; Chrzanowski, Wojciech; Stepnowski, Piotr; Namiesnik, Jacek

2016-01-01

This article presents an analysis of available literature data on metrological parameters of the amperometric gas sensors containing ionic liquids as an electrolyte. Four mechanism types of signal generation in amperometric sensors with ionic liquid are described. Moreover, this article describes the influence of selected physico-chemical properties of the ionic liquids on the metrological parameters of these sensors. Some metrological parameters are also compared for amperometric sensors with GDE and SPE electrodes and with ionic liquids for selected analytes.

The Opportunities and Challenges of Bringing New Metrology Equipment to Market

NASA Astrophysics Data System (ADS)

Perloff, David S.

2005-09-01

This paper provides an overview of the economic and technological factors which are driving the demand for new metrology and inspection equipment, the challenges and opportunities facing new companies in bringing such equipment to market, and the funding environment in which new companies must raise capital to finance their efforts. Seven metrology companies and one inspection equipment company that have received first-time venture backing since 2000 are used to illustrate how these specialized businesses are launched and funded.

Complexation of Contaminants and Aqueous-Phase Ozone with Cyclodextrin for Emerging Contaminant Oxidative Degradation

NASA Astrophysics Data System (ADS)

Khan, N. A.; Carroll, K. C.

2016-12-01

Recalcitrant emerging contaminants in groundwater, such as 1,4-dioxane, require strong oxidants for complete mineralization, whereas strong oxidant efficacy for in-situ chemical oxidation (ISCO) is limited by oxidant decay, reactivity, and non-specificity. Hydroxypropyl-β-cyclodextrin (HPβCD) was examined for its ability to stabilize aqueous phase ozone (O3) and prolong oxidation potential through inclusion complex formation. Partial transformation of HPβCD by O3 was observed but HPβCD proved to be sufficiently resilient and only partially degraded in the presence of O3. The formation of a HPβCD:O3 inclusion clathrate complex was observed, and multiple methods for binding constant measurements carried out and compared for HPβCD complexes with O3 and multiple contaminants. The presence of HPβCD increased the O3 half-life linearly with increasing HPβCD:O3 molar ratio. The O3 half-life in solutions increased by as much as 40-fold relative to HPβCD-free O3 solutions, and complexation reversibility was confirmed. Decay rate coefficients increased for 1,4-dioxane, trichloroethene, and trichloroethane likely due to the formation of HPβCD-O3-contaminant ternary complexes. These results suggest that the use of clathrate stabilizers, such as HPβCD, can support the development of a facilitated-transport enabled ISCO for the O3 treatment of groundwater impacted by recalcitrant emerging contaminants.

Performance and mechanism of simultaneous removal of Cd(II) and Congo red from aqueous solution by hierarchical vaterite spherulites

NASA Astrophysics Data System (ADS)

Chen, Yuan-Yuan; Yu, Sheng-Hui; Jiang, Hao-Fan; Yao, Qi-Zhi; Fu, Sheng-Quan; Zhou, Gen-Tao

2018-06-01

Hierarchical vaterite spherulites, synthesized by a simple injection-precipitation method at room temperature, were applied for the simultaneous removal of heavy metal Cd(II) and dye Congo red (CR) from aqueous solution. Batch experiments reveal that the maximum removal capacities of as-prepared vaterite spherulites to Cd(II) and CR are 984.5 and 89.0 mg/g, respectively, showing excellent removal performance for Cd(II) and CR. Furthermore, in the binary Cd(II)-CR system, the removal capacity of vaterite to Cd(II) is significantly enhanced at lower CR concentration (<100 mg/L), but inhibited at higher CR concentration (>100 mg/L). In contrast, the concurrent Cd(II) shows negligible effect on the CR removal. The simultaneous removal mechanism was investigated by FESEM, EDX, XRD, FT-IR and XPS techniques. The simultaneous removal of Cd(II) and CR in the binary system is shown to be a multistep process, involving the preferential adsorption of dye CR, stabilization of CR to vaterite, coordination of the adsorbed CR molecules with Cd(II), and transformation of vaterite into otavite. Given the facile and green synthesis procedure, and effective removal of Cd(II) and CR in the binary system, the obtained vaterite spherulites have considerable practical interest in integrative treatment of wastewater contaminated by heavy metals and dyes.

Stabilization and prolonged reactivity of aqueous-phase ozone with cyclodextrin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dettmer, Adam; Ball, Raymond; Boving, Thomas B.

Recalcitrant organic groundwater contaminants, such as 1,4-dioxane, may require strong oxidants for complete mineralization. However, their efficacy for in-situ chemical oxidation (ISCO) is limited by oxidant decay and reactivity. Hydroxypropyl-β-cyclodextrin (HPβCD) was examined for its ability to stabilize aqueous-phase ozone (O3) and prolong oxidation potential through inclusion complex formation. Partial transformation of HPβCD by O3 was observed. However, HPβCD proved to be sufficiently recalcitrant, because it was only partially degraded in the presence of O3. The formation of a HPβCD:O3 clathrate complex was observed, which stabilized decay of O3. The presence of HPβCD increased the O3 half-life linearly with increasingmore » HPβCD:O3 molar ratio. The O3 half-life in solutions increased by as much as 40-fold relative to HPβCD-free O3 solutions. Observed O3 release from HPβCD and indigo oxidation confirmed that the formation of the inclusion complex is reversible. This proof-of-concept study demonstrates that HPβCD can complex O3 while preserving its reactivity. These results suggest that the use of clathrate stabilizers, such as HPβCD, can support the development of a facilitated-transport enabled ISCO for the O3treatment of groundwater contaminated with recalcitrant compounds.« less

Status and path to a final EUVL reticle-handling solution

NASA Astrophysics Data System (ADS)

He, Long; Orvek, Kevin; Seidel, Phil; Wurm, Stefan; Underwood, Jon; Betancourt, Ernie

2007-03-01

In extreme ultraviolet lithography (EUVL), the lack of a suitable material to build conventional pellicles calls for industry standardization of new techniques for protection and handling throughout the reticle's lifetime. This includes reticle shipping, robotic handling, in-fab transport, storage, and uses in atmospheric environments for metrology and vacuum environments for EUV exposure. In this paper, we review the status of the industry-wide progress in developing EUVL reticle-handling solutions. We show the industry's leading reticle carrier approaches for particle-free protection, such as improvements in conventional single carrier designs and new EUVL-specific carrier concepts, including variations on a removable pellicle. Our test indicates dual pod approach of the removable pellicle led to nearly particle-free use during a simulated life cycle, at ~50nm inspection sensitivity. We will provide an assessment of the remaining technical challenges facing EUVL reticle-handling technology. Finally, we will review the progress of the SEMI EUVL Reticle-handling Task Force in its efforts to standardize a final EUV reticle protection and handling solution.

Characterization of cadmium biosorption by Exiguobacterium sp. isolated from farmland soil near Cu-Pb-Zn mine.

PubMed

Park, Jin Hee; Chon, Hyo-Taek

2016-06-01

Bacteria have the ability to bind heavy metals on their cell wall. Biosorption is a passive and energy-independent mechanism to adsorb heavy metals. The efficiency of heavy metal biosorption can vary depending on several factors such as the growth phase of bacteria, solution pH, and existence of competitive heavy metals. In this study, Exiguobacterium sp. isolated from farmland soil near a mine site were used, and optimal conditions for Cd biosorption in solution were investigated. As bacterial growth progressed, Cd biosorption increased, which is attributed to changes in the structure and composition of the cell wall during bacterial growth. The biosorption process was rapid and was completed within 30 min. Cadmium biosorption was highest at pH 7 due to the dissociation of hydrogen ions and the increase of negative charges with increasing pH. In the mixed metal solution of Cd, Pb, and Zn, the amount of biosorption was in the order of Pb>Cd>Zn while in a single metal solution, the order was Cd≥Pb>Zn. The maximum adsorption capacity for Cd by the isolated bacteria was 15.6 mg/g biomass, which was calculated from the Langmuir isotherm model. Different adsorption efficiencies under various environmental conditions indicate that, to control metal mobility, the conditions for biosorption should be optimized before applying bacteria. The results showed that the isolated bacteria can be used to immobilize metals in metal-contaminated wastewater.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Britten, J

WET-ETCH FIGURING (WEF) is an automated method of precisely figuring optical materials by the controlled application of aqueous etchant solution. This technology uses surface-tension-gradient-driven flow to confine and stabilize a wetted zone of an etchant solution or other aqueous processing fluid on the surface of an object. This wetted zone can be translated on the surface in a computer-controlled fashion for precise spatial control of the surface reactions occurring (e.g. chemical etching). WEF is particularly suitable for figuring very thin optical materials because it applies no thermal or mechanical stress to the material. Also, because the process is stress-free themore » workpiece can be monitored during figuring using interferometric metrology, and the measurements obtained can be used to control the figuring process in real-time--something that cannot be done with traditional figuring methods.« less

Development of a Highly Efficient Hybrid White Organic-Light-Emitting Diode with a Single Emission Layer by Solution Processing.

PubMed

Wu, Jun-Yi; Chen, Show-An

2018-02-07

We use a mixed host, 2,6-bis[3-(carbazol-9-yl)phenyl]pyridine blended with 20 wt % tris(4-carbazoyl-9-ylphenyl)amine, to lower the hole-injection barrier, along with the bipolar and high-photoluminescence-quantum-yield (Φ p = 84%), blue thermally activated delay fluorescence (TADF) material of 9,9-dimethyl-9,10-dihydroacridine-2,4,6-triphenyl-1,3,5-triazine (DMAC-TRZ) as a blue dopant to compose the emission layer for the fabrication of a TADF blue organic-light-emitting diode (BOLED). The device is highly efficient with the following performance parameters: maximum brightness (B max ) = 57586 cd/m 2 , maximum current efficiency (CE max ) = 35.3 cd/A, maximum power efficiency (PE max ) = 21.4 lm/W, maximum external quantum efficiency (EQE max ) = 14.1%, and CIE coordinates (0.18, 0.42). This device has the best performance recorded among the reported solution-processed TADF BOLEDs and has a low efficiency roll-off: at brightness values of 1000 and 5000 cd/m 2 , its CEs are close, being 35.1 and 30.1 cd/A, respectively. Upon further doping of the red phosphor Ir(dpm)PQ 2 (emission peak λ max = 595 nm) into the blue emission layer, we obtained a TADF-phosphor hybrid white organic-light-emitting diode (T-P hybrid WOLED) with high performance: B max = 43594 cd/m 2 , CE max = 28.8 cd/A, PE max = 18.1 lm/W, and CIE coordinates (0.38, 0.44). This B max = 43594 cd/m 2 is better than that of the vacuum-deposited WOLED with a blue TADF emitter, 10000 cd/m 2 . This is also the first report on a T-P hybrid WOLED with a solution-processed emitting layer.

Optical studies of CdSe/HgSe and CdSe/Ag2Se core/shell nanoparticles embedded in gelatin

NASA Astrophysics Data System (ADS)

Azhniuk, Yu M.; Dzhagan, V. M.; Raevskaya, A. E.; Stroyuk, A. L.; Kuchmiy, S. Ya; Valakh, M. Ya; Zahn, D. R. T.

2008-11-01

CdSe/HgSe and CdSe/Ag2Se core-shell nanoparticles are obtained by colloidal synthesis from aqueous solutions in the presence of gelatin. Optical absorption, luminescence, and Raman spectra of the nanoparticles obtained are measured. The variation of the optical spectra of CdSe/HgSe and CdSe/Ag2Se core-shell nanoparticles with the shell thickness is discussed. Sharp non-monotonous variation of the photoluminescence spectra at low shell coverage is observed.

Synthesis of Compositionally Defined Single-Crystalline Eu 3+ -Activated Molybdate–Tungstate Solid-Solution Composite Nanowires and Observation of Charge Transfer in a Novel Class of 1D CaMoO 4 –CaWO 4 :Eu 3+ –0D CdS/CdSe QD Nanoscale Heterostructures

DOE PAGES

Han, Jinkyu; McBean, Coray; Wang, Lei; ...

2015-02-10

As a first step, we have synthesized and optically characterized a systematic series of one-dimensional (1D) single-crystalline Eu³⁺-activated alkaline-earth metal tungstate/molybdate solid solution composite CaW₁₋ xMo xO₄ (0 ≤ ‘x’ ≤ 1) nanowires of controllable chemical composition using a modified template-directed methodology under ambient room-temperature conditions. Extensive characterization of the resulting nanowires has been performed using X-ray diffraction, electron microscopy, and optical spectroscopy. The crystallite size and single crystallinity of as-prepared 1D CaW₁₋ xMo xO₄: Eu³⁺ (0 ≤ ‘x’ ≤ 1) solid solution composite nanowires increase with increasing Mo component (‘x’). We note a clear dependence of luminescence output uponmore » nanowire chemical composition with our 1D CaW₁₋ xMo xO₄: Eu³⁺ (0 ≤ ‘x’ ≤ 1) evincing the highest photoluminescence (PL) output at ‘x’ = 0.8, amongst samples tested. Subsequently, coupled with either zero-dimensional (0D) CdS or CdSe quantum dots (QDs), we successfully synthesized and observed charge transfer processes in 1D CaW1-xMoxO4: Eu3+ (‘x’ = 0.8) – 0D QD composite nanoscale heterostructures. Our results show that CaW₁₋ xMo xO₄: Eu³⁺ (‘x’ = 0.8) nanowires give rise to PL quenching when CdSe QDs and CdS QDs are anchored onto the surfaces of 1D CaW₁₋ xMo xO₄: Eu³⁺ nanowires. The observed PL quenching is especially pronounced in CaW₁₋ xMo xO₄: Eu³⁺ (‘x’ = 0.8) – 0D CdSe QD heterostructures. Conversely, the PL output and lifetimes of CdSe and CdS QDs within these heterostructures are not noticeably altered as compared with unbound CdSe and CdS QDs. The difference in optical behavior between 1D Eu³⁺ activated tungstate and molybdate solid solution nanowires and the semiconducting 0D QDs within our heterostructures can be correlated with the relative positions of their conduction and valence energy band levels. We propose that the PL quenching can be attributed to a photo-induced electron transfer process from CaW₁₋ xMo xO₄: Eu³⁺ (‘x’ = 0.8) to both CdSe and CdS QDs, an assertion supported by complementary NEXAFS measurements.« less

Cadmium and zinc in soil solution extracts following the application of phosphate fertilizers.

PubMed

Lambert, Raphaël; Grant, Cynthia; Sauvé, Sébastien

2007-06-01

This study investigated the solubility of cadmium and zinc in soils after the application of phosphate fertilizers containing those two metals. The solubility of cadmium and zinc was assessed by measuring their concentration in soil water extracts. Three monoammonium phosphate fertilizers containing various amounts of metals were applied on cultivated fields for 3 years at three different rates. In order to investigate the effects of long-term applications of fertilizers on the solubility of Cd and Zn, a similar design was used to apply contaminated fertilizers to soils in a laboratory experiment using a single fertilizer addition equivalent to 15 years of application. Phosphate fertilizers increased the concentration of Cd in soil extracts compared to control in 87% and 80% of the treatments in field and laboratory experiments respectively. Both increasing the rate of application and using fertilizer containing more Cd lead to higher Cd concentrations in extracts for the field and the laboratory experiments. The addition of the equivalent of 15 years of fertilizer application in the laboratory results in higher Cd concentration in extracts compared to the field experiment. For Zn, the fertilizer treatments enhanced the metal solution concentration in 83% of field treatments, but no significant correlations could be found between Zn inputs and its concentration in solution. In the laboratory, fertilizer additions increase the Zn concentrations in 53% of the treatments and decrease it in most of the other treatments. The decrease in Zn concentrations in the laboratory trial is attributed to the higher phosphate concentrations in the soil solution; which is presumed to have contributed to the precipitation of Zn-phosphates. For both trials, the metal concentrations in soil extracts cannot be related to the Zn concentration in the fertilizer or the rate of application. The high Zn to Cd ratio is presumably responsible for the Cd increase in the soil extracts due to competitive displacement by Zn. Finally, the observed acidification of soils with fertilizer application will also contribute to metal solubilisation.

Cadmium uptake and xylem loading are active processes in the hyperaccumulator Sedum alfredii.

PubMed

Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Li, Ting-qiang; He, Zhen-li

2009-04-01

Sedum alfredii is a well known cadmium (Cd) hyperaccumulator native to China; however, the mechanism behind its hyperaccumulation of Cd is not fully understood. Through several hydroponic experiments, characteristics of Cd uptake and translocation were investigated in the hyperaccumulating ecotype (HE) of S. alfredii in comparison with its non-hyperaccumulating ecotype (NHE). The results showed that at Cd level of 10 microM measured Cd uptake in HE was 3-4 times higher than the implied Cd uptake calculated from transpiration rate. Furthermore, inhibition of transpiration rate in the HE has no essential effect on Cd accumulation in shoots of the plants. Low temperature treatment (4 degrees C) significantly inhibited Cd uptake and reduced upward translocation of Cd to shoots for 9 times in HE plants, whereas no such effect was observed in NHE. Cadmium concentration was 3-4-fold higher in xylem sap of HE, as compared with that in external uptake solution, whereas opposite results were obtained for NHE. Cadmium concentration in xylem sap of HE was significantly reduced by the addition of metabolic inhibitors, carbonyl cyanide m-chlorophenylhydrazone (CCCP) and 2,4-dinitrophenol (DNP), in the uptake solutions, whereas no such effect was noted in NHE. These results suggest that Cd uptake and translocation is an active process in plants of HE S. alfredii, symplastic pathway rather than apoplastic bypass contributes greatly to root uptake, xylem loading and translocation of Cd to the shoots of HE, in comparison with the NHE plants.

Accuracy optimization with wavelength tunability in overlay imaging technology

NASA Astrophysics Data System (ADS)

Lee, Honggoo; Kang, Yoonshik; Han, Sangjoon; Shim, Kyuchan; Hong, Minhyung; Kim, Seungyoung; Lee, Jieun; Lee, Dongyoung; Oh, Eungryong; Choi, Ahlin; Kim, Youngsik; Marciano, Tal; Klein, Dana; Hajaj, Eitan M.; Aharon, Sharon; Ben-Dov, Guy; Lilach, Saltoun; Serero, Dan; Golotsvan, Anna

2018-03-01

As semiconductor manufacturing technology progresses and the dimensions of integrated circuit elements shrink, overlay budget is accordingly being reduced. Overlay budget closely approaches the scale of measurement inaccuracies due to both optical imperfections of the measurement system and the interaction of light with geometrical asymmetries of the measured targets. Measurement inaccuracies can no longer be ignored due to their significant effect on the resulting device yield. In this paper we investigate a new approach for imaging based overlay (IBO) measurements by optimizing accuracy rather than contrast precision, including its effect over the total target performance, using wavelength tunable overlay imaging metrology. We present new accuracy metrics based on theoretical development and present their quality in identifying the measurement accuracy when compared to CD-SEM overlay measurements. The paper presents the theoretical considerations and simulation work, as well as measurement data, for which tunability combined with the new accuracy metrics is shown to improve accuracy performance.

Simulations of Scatterometry Down to 22 nm Structure Sizes and Beyond with Special Emphasis on LER

NASA Astrophysics Data System (ADS)

Osten, W.; Ferreras Paz, V.; Frenner, K.; Schuster, T.; Bloess, H.

2009-09-01

In recent years, scatterometry has become one of the most commonly used methods for CD metrology. With decreasing structure size for future technology nodes, the search for optimized scatterometry measurement configurations gets more important to exploit maximum sensitivity. As widespread industrial scatterometry tools mainly still use a pre-set measurement configuration, there are still free parameters to improve sensitivity. Our current work uses a simulation based approach to predict and optimize sensitivity of future technology nodes. Since line edge roughness is getting important for such small structures, these imperfections of the periodic continuation cannot be neglected. Using fourier methods like e.g. rigorous coupled wave approach (RCWA) for diffraction calculus, nonperiodic features are hard to reach. We show that in this field certain types of fieldstitching methods show nice numerical behaviour and lead to useful results.

1.5 nm fabrication of test patterns for characterization of metrological systems

DOE PAGES

Babin, Sergey; Calafiore, Giuseppe; Peroz, Christophe; ...

2015-11-06

Any metrology tool is only as good as it is calibrated. The characterization of metrology systems requires test patterns at a scale about ten times smaller than the measured features. The fabrication of patterns with linewidths down to 1.5 nm is described. The test sample was designed in such a way that the distribution of linewidths appears to be random at any location. This pseudorandom test pattern is used to characterize dimensional metrology equipment over its entire dynamic range by extracting the modulation transfer function of the system. The test pattern contains alternating lines of silicon and tungsten silicide, eachmore » according to its designed width. As a result, the fabricated test samples were imaged using a transmission electron microscope, a scanning electron microscope, and an atomic force microscope. (C) 2015 American Vacuum Society.« less

Quantifying Human Response: Linking metrological and psychometric characterisations of Man as a Measurement Instrument

NASA Astrophysics Data System (ADS)

Pendrill, L. R.; Fisher, William P., Jr.

2013-09-01

A better understanding of how to characterise human response is essential to improved person-centred care and other situations where human factors are crucial. Challenges to introducing classical metrological concepts such as measurement uncertainty and traceability when characterising Man as a Measurement Instrument include the failure of many statistical tools when applied to ordinal measurement scales and a lack of metrological references in, for instance, healthcare. The present work attempts to link metrological and psychometric (Rasch) characterisation of Man as a Measurement Instrument in a study of elementary tasks, such as counting dots, where one knows independently the expected value because the measurement object (collection of dots) is prepared in advance. The analysis is compared and contrasted with recent approaches to this problem by others, for instance using signal error fidelity.

Influence of the air’s refractive index on precision angle metrology with autocollimators

NASA Astrophysics Data System (ADS)

Geckeler, Ralf D.; Křen, Petr; Just, Andreas; Schumann, Matthias; Krause, Michael

2018-07-01

In this paper, we discuss a substantial—though previously neglected—error source in precision metrology with autocollimators, specifically, changes in the air’s refractive index, with a focus on the dominant impact of pressure changes. Pressure decreases with increasing elevation above sea level and is subject to substantial variation due to weather changes. It causes changes in an autocollimator’s angle response which are proportional to the measured angle and which increase linearly with the beam length and air pressure. We characterise this important influence in detail by using extended theoretical and experimental investigations and derive strategies for correcting it. We discuss its implications for the comparison of autocollimator calibrations performed at different metrology institutes which is crucial for validating their calibration capabilities. This work aims at approaching fundamental limits in angle metrology with autocollimators.

Phase shifting white light interferometry using colour CCD for optical metrology and bio-imaging applications

NASA Astrophysics Data System (ADS)

Upputuri, Paul Kumar; Pramanik, Manojit

2018-02-01

Phase shifting white light interferometry (PSWLI) has been widely used for optical metrology applications because of their precision, reliability, and versatility. White light interferometry using monochrome CCD makes the measurement process slow for metrology applications. WLI integrated with Red-Green-Blue (RGB) CCD camera is finding imaging applications in the fields optical metrology and bio-imaging. Wavelength dependent refractive index profiles of biological samples were computed from colour white light interferograms. In recent years, whole-filed refractive index profiles of red blood cells (RBCs), onion skin, fish cornea, etc. were measured from RGB interferograms. In this paper, we discuss the bio-imaging applications of colour CCD based white light interferometry. The approach makes the measurement faster, easier, cost-effective, and even dynamic by using single fringe analysis methods, for industrial applications.

Confocal Microscopy

NASA Astrophysics Data System (ADS)

Liu, Jian; Tan, Jiubin

2016-12-01

The confocal microscope is appropriate for imaging cells or the measurement of industrial artefacts. However, junior researchers and instrument users sometimes misuse imaging concepts and metrological characteristics, such as position resolution in industrial metrology and scale resolution in bio-imaging. And, metrological characteristics or influence factors in 3D measurement such as height assessment error caused by 3D coupling effect are so far not yet identified. In this book, the authors outline their practices by the working experiences on standardization and system design. This book assumes little previous knowledge of optics, but rich experience in engineering of industrial measurements, in particular with profile metrology or areal surface topography will be very helpful to understand the theoretical concerns and value of the technological advances. It should be useful for graduate students or researchers as extended reading material, as well as microscope users alongside their handbook.

DLP-based 3D metrology by structured light or projected fringe technology for life sciences and industrial metrology

NASA Astrophysics Data System (ADS)

Frankowski, G.; Hainich, R.

2009-02-01

Since the mid-eighties, a fundamental idea for achieving measuring accuracy in projected fringe technology was to consider the projected fringe pattern as an interferogram and evaluate it on the basis of advanced algorithms widely used for phase measuring in real-time interferometry. A fundamental requirement for obtaining a sufficiently high degree of measuring accuracy with this so-called "phase measuring projected fringe technology" is that the projected fringes, analogous to interference fringes, must have a cos2-shaped intensity distribution. Until the mid-nineties, this requirement for the projected fringe pattern measurement technology presented a basic handicap for its wide application in 3D metrology. This situation changed abruptly, when in the nineties Texas Instruments introduced to the market advanced digital light projection on the basis of micro mirror based projection systems, socalled DLP technology, which also facilitated the generation and projection of cos2-shaped intensity and/or fringe patterns. With this DLP technology, which from its original approach was actually oriented towards completely different applications such as multimedia projection, Texas Instruments boosted phase-measuring fringe projection in optical 3D metrology to a worldwide breakthrough both for medical as well as industrial applications. A subject matter of the lecture will be to present the fundamental principles and the resulting advantages of optical 3D metrology based on phase-measuring fringe projection using DLP technology. Further will be presented and discussed applications of the measurement technology in medical engineering and industrial metrology.

[The EFS metrology: From the production to the reason].

PubMed

Reifenberg, J-M; Riout, E; Leroy, A; Begue, S

2014-06-01

In order to answer statutory requirements and to anticipate the future needs and standards, the EFS is committed, since a few years, in a process of harmonization of its metrology function. In particular, the institution has opted for the skills development by internalizing the metrological traceability of the main critical quantities (temperature, volumetric) measurements. The development of metrology so resulted in a significant increase in calibration and testing activities. Methods are homogenized and improved through accreditations. The investment strategies are based on more and more demanding specifications. The performance of the equipments is better known and mastered. Technical expertise and maturity of the national metrology function today are assets to review in more informed ways the appropriateness of the applied periodicities. Analysis of numerous information and data in the calibration and testing reports could be pooled and operated on behalf of the unique establishment. The objective of this article is to illustrate these reflections with a few examples from of a feedback of the EFS Pyrénées Méditerranée. The analysis of some methods of qualification, the exploitation of the historical metrology in order to quantify the risk of non-compliance, and to adapt the control strategy, analysis of the criticality of an instrument in a measurement process, risk analyses are tools that deserve to be more widely exploited for that discipline wins in efficiency at the national level. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Removal of Pb(II), Cd(II), Cu(II), and Zn(II) by hematite nanoparticles: effect of sorbent concentration, pH, temperature, and exhaustion.

PubMed

Shipley, Heather J; Engates, Karen E; Grover, Valerie A

2013-03-01

Nanoparticles offer the potential to improve environmental treatment technologies due to their unique properties. Adsorption of metal ions (Pb(II), Cd(II), Cu(II), Zn(II)) to nanohematite was examined as a function of sorbent concentration, pH, temperature, and exhaustion. Adsorption experiments were conducted with 0.05, 0.1, and 0.5 g/L nanoparticles in a pH 8 solution and in spiked San Antonio tap water. The adsorption data showed the ability of nanohematite to remove Pb, Cd, Cu, and Zn species from solution with adsorption increasing as the nanoparticle concentration increased. At 0.5 g/L nanohematite, 100 % Pb species adsorbed, 94 % Cd species adsorbed, 89 % Cu species adsorbed and 100 % Zn species adsorbed. Adsorption kinetics for all metals tested was described by a pseudo second-order rate equation with lead having the fastest rate of adsorption. The effect of temperature on adsorption showed that Pb(II), Cu(II), and Cd(II) underwent an endothermic reaction, while Zn(II) underwent an exothermic reaction. The nanoparticles were able to simultaneously remove multiple metals species (Zn, Cd, Pb, and Cu) from both a pH 8 solution and spiked San Antonio tap water. Exhaustion experiments showed that at pH 8, exhaustion did not occur for the nanoparticles but adsorption does decrease for Cd, Cu, and Zn species but not Pb species. The strong adsorption coupled with the ability to simultaneously remove multiple metal ions offers a potential remediation method for the removal of metals from water.

Development of a certified reference material (NMIJ CRM 7505-a) for the determination of trace elements in tea leaves.

PubMed

Zhu, Yanbei; Narukawa, Tomohiro; Inagaki, Kazumi; Kuroiwa, Takayoshi; Chiba, Koichi

2011-01-01

A certified reference material (CRM) for trace elements in tea leaves has been developed in National Metrology Institute of Japan (NMIJ). The CRM was provided as a dry powder (<90 µm) after frozen pulverization of washed and dried fresh tea leaves from a tea plant farm in Shizuoka Prefecture, Japan. Characterization of the property value for each element was carried out exclusively by NMIJ with at least two independent analytical methods, including inductively coupled plasma mass spectrometry (ICP-MS), high-resolution (HR-) ICP-MS, isotope-dilution (ID-) ICP-MS, inductively coupled plasma optical emission spectrometry (ICP-OES), graphite-furnace atomic-absorption spectrometry (GF-AAS) and flame atomic-absorption spectrometry (FAAS). Property values were provided for 19 elements (Ca, K, Mg, P, Al, B, Ba, Cd, Cu, Fe, Li, Mn, Na, Ni, Pb, Rb, Sr, Zn and Co) and informative values for 18 elements (Ti, V, Cr, Y, and all of the lanthanides, except for Pm whose isotopes are exclusively radioactive). The concentration ranges of property values and informative values were from 1.59% (mass) of K to 0.0139 mg kg(-1) of Cd and from 0.6 mg kg(-1) of Ti to 0.0014 mg kg(-1) of Lu, respectively. Combined relatively standard uncertainties of the property values were estimated by considering the uncertainties of the homogeneity, analytical methods, characterization, calibration standard, and dry-mass correction factor. The range of the relative combined standard uncertainties was from 1.5% of Mg and K to 4.1% of Cd.

Extension of optical lithography by mask-litho integration with computational lithography

NASA Astrophysics Data System (ADS)

Takigawa, T.; Gronlund, K.; Wiley, J.

2010-05-01

Wafer lithography process windows can be enlarged by using source mask co-optimization (SMO). Recently, SMO including freeform wafer scanner illumination sources has been developed. Freeform sources are generated by a programmable illumination system using a micro-mirror array or by custom Diffractive Optical Elements (DOE). The combination of freeform sources and complex masks generated by SMO show increased wafer lithography process window and reduced MEEF. Full-chip mask optimization using source optimized by SMO can generate complex masks with small variable feature size sub-resolution assist features (SRAF). These complex masks create challenges for accurate mask pattern writing and low false-defect inspection. The accuracy of the small variable-sized mask SRAF patterns is degraded by short range mask process proximity effects. To address the accuracy needed for these complex masks, we developed a highly accurate mask process correction (MPC) capability. It is also difficult to achieve low false-defect inspections of complex masks with conventional mask defect inspection systems. A printability check system, Mask Lithography Manufacturability Check (M-LMC), is developed and integrated with 199-nm high NA inspection system, NPI. M-LMC successfully identifies printable defects from all of the masses of raw defect images collected during the inspection of a complex mask. Long range mask CD uniformity errors are compensated by scanner dose control. A mask CD uniformity error map obtained by mask metrology system is used as input data to the scanner. Using this method, wafer CD uniformity is improved. As reviewed above, mask-litho integration technology with computational lithography is becoming increasingly important.

Distributed force probe bending model of critical dimension atomic force microscopy bias

NASA Astrophysics Data System (ADS)

Ukraintsev, Vladimir A.; Orji, Ndubuisi G.; Vorburger, Theodore V.; Dixson, Ronald G.; Fu, Joseph; Silver, Rick M.

2013-04-01

Critical dimension atomic force microscopy (CD-AFM) is a widely used reference metrology technique. To characterize modern semiconductor devices, small and flexible probes, often 15 to 20 nm in diameter, are used. Recent studies have reported uncontrolled and significant probe-to-probe bias variation during linewidth and sidewall angle measurements. To understand the source of these variations, tip-sample interactions between high aspect ratio features and small flexible probes, and their influence on measurement bias, should be carefully studied. Using theoretical and experimental procedures, one-dimensional (1-D) and two-dimensional (2-D) models of cylindrical probe bending relevant to carbon nanotube (CNT) AFM probes were developed and tested. An earlier 1-D bending model was refined, and a new 2-D distributed force (DF) model was developed. Contributions from several factors were considered, including: probe misalignment, CNT tip apex diameter variation, probe bending before snapping, and distributed van der Waals-London force. A method for extracting Hamaker probe-surface interaction energy from experimental probe-bending data was developed. Comparison of the new 2-D model with 1-D single point force (SPF) model revealed a difference of about 28% in probe bending. A simple linear relation between biases predicted by the 1-D SPF and 2-D DF models was found. The results suggest that probe bending can be on the order of several nanometers and can partially explain the observed CD-AFM probe-to-probe variation. New 2-D and three-dimensional CD-AFM data analysis software is needed to take full advantage of the new bias correction modeling capabilities.

Excitonic Solids.

DTIC Science & Technology

1983-11-03

we believe, structural second order phase transitions at the same temperatu "es that the anomalously large diamagnetism disappears and microwave...precipitation from aqueous solution, and by acid doping. The differently doped starting materials were analyzed for C1 and other impurities before being...solution can be given as IV. ACID -DOPING TECHNIQUE -a- [CdCl. ] Samples of pure CdS were stirred and heated with vari- am- = =K[C-]’a0, ous HCI and

Electrically assisted liquid-phase microextraction combined with capillary electrophoresis for quantification of propranolol enantiomers in human body fluids.

PubMed

Tabani, Hadi; Fakhari, Ali Reza; Shahsavani, Abolfath; Gharari Alibabaou, Hossein

2014-05-01

In this study, electromembrane extraction (EME) combined with cyclodextrin (CD)-modified capillary electrophoresis (CE) was applied for the extraction, separation, and quantification of propranolol (PRO) enantiomers from biological samples. The PRO enantiomers were extracted from aqueous donor solutions, through a supported liquid membrane (SLM) consisting of 2-nitrophenyl octyl ether (NPOE) impregnated on the wall of the hollow fiber, and into a 20-μL acidic aqueous acceptor solution into the lumen of hollow fiber. Important parameters affecting EME efficiency such as extraction voltage, extraction time, pH of the donor and acceptor solutions were optimized using a Box-Behnken design (BBD). Then, under these optimized conditions, the acceptor solution was analyzed using an optimized CD-modified CE. Several types of CD were evaluated and best results were obtained using a fused-silica capillary with ammonium acetate (80 mM, pH 2.5) containing 8 mM hydroxypropyl-β-CD as a chiral selector, applied voltage of 18 kV, and temperature of 20°C. The relative recoveries were obtained in the range of 78-95%. Finally, the performance of the present method was evaluated for the extraction and determination of PRO enantiomers in real biological samples. © 2014 Wiley Periodicals, Inc.

Ion exchange during heavy metal bio-sorption from aqueous solution by dried biomass of macrophytes.

PubMed

Verma, V K; Tewari, Saumyata; Rai, J P N

2008-04-01

In this study, potentials of oven dried biomass of Eichhornia crassipes, Valisneria spiralis and Pistia stratiotes, were examined in terms of their heavy metal (Cd, Ni, Zn, Cu, Cr and Pb) sorption capacity, from individual-metal and multi-metal aqueous solutions at pH 6.0+/-0.1 (a popular pH of industrial effluent). V. spiralis was the most and E. crassipes was the least efficient for removal of all the metals. Cd, Pb and Zn were efficiently removed by all the three biomass. Cd was removed up to 98% by V. spiralis. Sorption data for Cr, Ni and Cd fitted better to Langmuir isotherm equation, while, the sorption data for Pb, Zn and Cu fitted better to Freundlich isotherm equation. In general, the presence of other metal ions did not influence significantly the targeted metal sorption capacity of the test plant biomasses. Ion exchange was proven the main mechanism involved in bio-sorption and there was a strong ionic balance between adsorbed (H(+) and M(2+)) to the released ions (Na(+) and K(+)) to and from the biomass. No significant difference was observed in the metal exchanged amount, by doubling of metal concentration (15-30 mg/l) in the solution and employing individual-metal and multi-metal solutions.

Comparison of in situ DGT measurement with ex situ methods for predicting cadmium bioavailability in soils with combined pollution to biotas.

PubMed

Wang, Peifang; Liu, Cui; Yao, Yu; Wang, Chao; Wang, Teng; Yuan, Ye; Hou, Jun

2017-05-01

To assess the capabilities of the different techniques in predicting Cadmium (Cd) bioavailability in Cd-contaminated soils with the addition of Zn, one in situ technique (diffusive gradients in thin films; DGT) was compared with soil solution concentration and four widely used single-step extraction methods (acetic acid, EDTA, sodium acetate and CaCl 2 ). Wheat and maize were selected as tested species. The results demonstrated that single Cd-polluted soils inhibited the growth of wheat and maize significantly compared with control plants; the shoot and root biomasses of the plants both dropped significantly (P < 0.05). The addition of Zn exhibited a strong antagonism to the physiological toxicity induced by Cd. The Pearson correlation coefficient presented positive correlations (P < 0.01, R > 0.9) between Cd concentrations in two plants and Cd bioavailability indicated by each method in soils. Consequently, the results indicated that the DGT technique could be regarded as a good predictor of Cd bioavailability to plants, comparable to soil solution concentration and the four single-step extraction methods. Because the DGT technique can offer in situ data, it is expected to be widely used in more areas.

Glutathione-capped CdTe nanocrystals as probe for the determination of fenbendazole

NASA Astrophysics Data System (ADS)

Li, Qin; Tan, Xuanping; Li, Jin; Pan, Li; Liu, Xiaorong

2015-04-01

Water-soluble glutathione (GSH)-capped CdTe quantum dots (QDs) were synthesized. In pH 7.1 PBS buffer solution, the interaction between GSH-capped CdTe QDs and fenbendazole (FBZ) was investigated by spectroscopic methods, including fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy, and resonance Rayleigh scattering (RRS) spectroscopy. In GSH-capped CdTe QDs solution, the addition of FBZ results in the fluorescence quenching and RRS enhancement of GSH-capped CdTe QDs. And the quenching intensity (enhanced RRS intensity) was proportional to the concentration of FBZ in a certain range. Investigation of the interaction mechanism, proved that the fluorescence quenching and RRS enhancement of GSH-capped CdTe QDs by FBZ is the result of electrostatic attraction. Based on the quenching of fluorescence (enhancement of RRS) of GSH-capped CdTe QDs by FBZ, a novel, simple, rapid and specific method for FBZ determination was proposed. The detection limit for FBZ was 42 ng mL-1 (3.4 ng mL-1) and the quantitative determination range was 0-2.8 μg mL-1 with a correlation of 0.9985 (0.9979). The method has been applied to detect FBZ in real simples and with satisfactory results.

Graphene and CdS nanocomposite: a facile interface for construction of DNA-based electrochemical biosensor and its application to the determination of phenformin.

PubMed

Zeng, Lijiao; Wang, Rui; Zhu, Lihua; Zhang, Jingdong

2013-10-01

Graphene/cadmium sulphide (GR-CdS) nanocomposite was synthesized via a low temperature process in aqueous solution. The as-prepared nanocomposite was characterized by scanning electron microscopy, UV-visible spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The impedance analysis indicated that GR-CdS nanocomposite possessed outstanding electrochemical performance for facile electron transfer. When DNA was immobilized on GR-CdS (DNA/GR-CdS) modified electrode, the electrochemical oxidation of guanine and adenine in DNA residue bases was significantly promoted. Due to the interaction of DNA with phenformin, the voltammetric current of guanine or adenine on the DNA/GR-CdS electrode was decreased when phenformin was present in the electrolytic solution. Under optimized conditions, the signal of guanine on DNA/GR-CdS electrode decreased linearly with increasing the concentration of phenformin in the range of 1.0×10(-6)molL(-1) to 1.0×10(-3)molL(-1). The proposed DNA-based electrochemical biosensor was successfully applied to the determination of phenformin in real samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of Phosphine-Free Selenium Precursor Reactivity on The Optical and Vibrational properties of Colloidal CdSe Nanocrystals

NASA Astrophysics Data System (ADS)

Thi, L. A.; Lieu, N. T. T.; Hoa, N. M.; Tran, N.; Binh, N. T.; Quang, V. X.; Nghia, N. X.

2018-03-01

Phosphine-free selenium precursor solutions have been prepared by heating at temperatures ranging from 160 °C to 240 °C and studied by means of infrared absorption spectroscopy. The colloidal CdSe nanocrystals (NCs) synthesized from all those solutions by the wet chemical method. The influence of heating temperature on the chemical reactivity of selenium precursor and its role on the optical and vibrational properties of CdSe NCs are discussed in details. Their morphology, particle size, structural, optical and vibrational properties were investigated using transmission electron microscopy, X-ray diffraction, UV-Vis, fluorescence and Raman spectroscopy, respectively.

Enhanced Carrier Collection from CdS Passivated Grains in Solution-Processed Cu2ZnSn(S,Se)4 Solar Cells.

PubMed

Werner, Melanie; Keller, Debora; Haass, Stefan G; Gretener, Christina; Bissig, Benjamin; Fuchs, Peter; La Mattina, Fabio; Erni, Rolf; Romanyuk, Yaroslav E; Tiwari, Ayodhya N

2015-06-10

Solution processing of Cu2ZnSn(S,Se)4 (CZTSSe)-kesterite solar cells is attractive because of easy manufacturing using readily available metal salts. The solution-processed CZTSSe absorbers, however, often suffer from poor morphology with a bilayer structure, exhibiting a dense top crust and a porous bottom layer, albeit yielding efficiencies of over 10%. To understand whether the cell performance is limited by this porous layer, a systematic compositional study using (scanning) transmission electron microscopy ((S)TEM) and energy-dispersive X-ray spectroscopy of the dimethyl sulfoxide processed CZTSSe absorbers is presented. TEM investigation revealed a thin layer of CdS that is formed around the small CZTSSe grains in the porous bottom layer during the chemical bath deposition step. This CdS passivation is found to be beneficial for the cell performance as it increases the carrier collection and facilitates the electron transport. Electron-beam-induced current measurements reveal an enhanced carrier collection for this buried region as compared to reference cells with evaporated CdS.

Adsorption of Cd2+ ions on plant mediated SnO2 nanoparticles

NASA Astrophysics Data System (ADS)

Haq, Sirajul; Rehman, Wajid; Waseem, Muhammad; Shahid, Muhammad; Mahfooz-ur-Rehman; Hussain Shah, Khizar; Nawaz, Mohsan

2016-10-01

Plant mediated SnO2 nanoparticles were synthesized by using SnCl4.5H2O as a precursor material. The nanoparticles were then characterized for BET surface area measurements, energy dispersive x-rays (EDX), scanning electron microscopy (SEM), UV-vis diffuse reflectance (DRS) spectra and x-rays diffraction (XRD) analysis. The successful synthesis of SnO2 nanoparticles was confirmed by EDX analysis. The particle sizes were in the range 19-27 nm whereas the crystallite size computed from XRD measurement was found to be 19.9 nm. Batch adsorption technique was employed for the removal of Cd2+ ions from aqueous solution. The sorption studies of Cd2+ ions were performed at pHs 4 and 6. The equilibrium concentration of Cd2+ ions was determined by atomic absorption spectrometer (flame mode). The uptake of Cd2+ ions was affected by initial concentration, pH and temperature of the electrolytic solution. It was observed that the adsorption of Cd2+ ions enhanced with increase in the initial concentration of Cd2+ ions whereas a decrease in the percent adsorption was detected. From the thermodynamic parameters, the adsorption process was found spontaneous and endothermic in nature. The n values confirmed 2:1 exchange mechanism between surface protons and Cd2+ ions.

CdS/TiO2 photoanodes via solution ion transfer method for highly efficient solar hydrogen generation

NASA Astrophysics Data System (ADS)

Krishna Karuturi, Siva; Yew, Rowena; Reddy Narangari, Parvathala; Wong-Leung, Jennifer; Li, Li; Vora, Kaushal; Tan, Hark Hoe; Jagadish, Chennupati

2018-03-01

Cadmium sulfide (CdS) is a unique semiconducting material for solar hydrogen generation applications with a tunable, narrow bandgap that straddles water redox potentials. However, its potential towards efficient solar hydrogen generation has not yet been realized due to low photon-to-current conversions, high charge carrier recombination and the lack of controlled preparation methods. In this work, we demonstrate a highly efficient CdS/TiO2 heterostructured photoelectrode using atomic layer deposition and solution ion transfer reactions. Enabled by the well-controlled deposition of CdS nanocrystals on TiO2 inverse opal (TiIO) nanostructures using the proposed method, a saturation photocurrent density of 9.1 mA cm-2 is realized which is the highest ever reported for CdS-based photoelectrodes. We further demonstrate that the passivation of a CdS surface with an ultrathin amorphous layer (˜1.5 nm) of TiO2 improves the charge collection efficiency at low applied potentials paving the way for unassisted solar hydrogen generation.

Compartmental efflux analysis and removal of extracellular cadmium from roots. [Agrostis gigantea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rauser, W.E.

1987-09-01

Profiles of /sup 109/Cd efflux from roots into three solutions were determined for young intact plants of Agrostis gigantea and maize. The solutions were (a) nutrient culture medium containing 3 micromolar Cd at room temperature, (b) ice-cold 5 millimolar CaCl/sub 2/, and (c) ice-cold 5 millimolar PbCl/sub 2/. Efflux profiles were clearly resolved into three easily discernible components having fast, medium, and slow exchange rates. These results were unexpected for the situation where some intracellular Cd was present both as extractable Cd-binding peptide and in electron-dense granules within the cytoplasm and the vacuoles. Adding a fourth compartment to the curve-fittingmore » model produced a splitting of the fast exchanging component. Use of these efflux kinetics to estimate Cd fluxes through membranes was inappropriate. However, they were useful in determining optimal washing times for the removal of extracellular Cd. A 10 minute wash in ice-cold 5 millimolar CaCl/sub 2/ is recommended for this purpose for Agrostis and maize roots.« less

Ambient Optomechanical Alignment and Pupil Metrology for the Flight Instruments Aboard the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Coulter, Phillip; Beaton, Alexander; Gum, Jeffrey S.; Hadjimichael, Theodore J.; Hayden, Joseph E.; Hummel, Susann; Hylan, Jason E.; Lee, David; Madison, Timothy J.; Maszkiewicz, Michael;

Signal processing for order 10 PM accuracy displacement metrology in real-world scientific applications

NASA Astrophysics Data System (ADS)

Halverson, Peter G.; Loya, Frank M.

2017-11-01

Projects such as the Space Interferometry Mission (SIM) [1] and Terrestrial Planet Finder (TPF) [2] rely heavily on sub-nanometer accuracy metrology systems to define their optical paths and geometries. The James Web Space Telescope (JWST) is using this metrology in a cryogenic dilatometer for characterizing material properties (thermal expansion, creep) of optical materials. For all these projects, a key issue has been the reliability and stability of the electronics that convert displacement metrology signals into real-time distance determinations. A particular concern is the behavior of the electronics in situations where laser heterodyne signals are weak or noisy and subject to abrupt Doppler shifts due to vibrations or the slewing of motorized optics. A second concern is the long-term (hours to days) stability of the distance measurements under conditions of drifting laser power and ambient temperature. This paper describes heterodyne displacement metrology gauge signal processing methods that achieve satisfactory robustness against low signal strength and spurious signals, and good long-term stability. We have a proven displacement-measuring approach that is useful not only to space-optical projects at JPL, but also to the wider field of distance measurements.

On-orbit Metrology and Calibration Requirements for Space Station Activities Definition Study

NASA Technical Reports Server (NTRS)

Cotty, G. M.; Ranganathan, B. N.; Sorrell, A. L.

1989-01-01

The Space Station is the focal point for the commercial development of space. The long term routine operation of the Space Station and the conduct of future commercial activities suggests the need for in-space metrology capabilities analogous when possible to those on-Earth. The ability to perform periodic calibrations and measurements with proper traceability is imperative for the routine operation of the Space Station. An initial review, however, indicated a paucity of data related to metrology and calibration requirements for in-space operations. This condition probably exists because of the highly developmental aspect of space activities to date, their short duration, and nonroutine nature. The on-orbit metrology and calibration needs of the Space Station were examined and assessed. In order to achieve this goal, the following tasks were performed: an up-to-date literature review; identification of on-orbit calibration techniques; identification of sensor calibration requirements; identification of calibration equipment requirements; definition of traceability requirements; preparation of technology development plans; and preparation of the final report. Significant information and major highlights pertaining to each task is presented. In addition, some general (generic) conclusions/observations and recommendations that are pertinent to the overall in-space metrology and calibration activities are presented.

Developments in optical modeling methods for metrology

NASA Astrophysics Data System (ADS)

Davidson, Mark P.

1999-06-01

Despite the fact that in recent years the scanning electron microscope has come to dominate the linewidth measurement application for wafer manufacturing, there are still many applications for optical metrology and alignment. These include mask metrology, stepper alignment, and overlay metrology. Most advanced non-optical lithographic technologies are also considering using topics for alignment. In addition, there have been a number of in-situ technologies proposed which use optical measurements to control one aspect or another of the semiconductor process. So optics is definitely not dying out in the semiconductor industry. In this paper a description of recent advances in optical metrology and alignment modeling is presented. The theory of high numerical aperture image simulation for partially coherent illumination is discussed. The implications of telecentric optics on the image simulation is also presented. Reciprocity tests are proposed as an important measure of numerical accuracy. Diffraction efficiencies for chrome gratings on reticles are one good way to test Kirchoff's approximation as compared to rigorous calculations. We find significant differences between the predictions of Kirchoff's approximation and rigorous methods. The methods for simulating brightfield, confocal, and coherence probe microscope imags are outlined, as are methods for describing aberrations such as coma, spherical aberration, and illumination aperture decentering.

Removal and recovery of p-phenylenediamines developing compounds from photofinishing lab-washwater using clinoptilolite tuffs from Greece.

PubMed

Vlessidis, A G; Triantafillidis, C S; Evmiridis, N P

2001-04-01

Clinoptilolite tuffs from areas in Thrace region of Greece are compared with synthetic zeolites NaY and NH4Y for the uptake of N4-ethyl-N4-(2-methansulphonamidoethyl)-2-methyl-1,4-phenylenediamin (sesquisulphate, monohydrate) with the trade name CD-3 for the purpose to be used for clean-up and recycling photo-finishing and photo-developing washwaters. The cation-exchange capacity is found to be 6.15-11.1 mg/g for zeoliferous tuffs at equilibrium concentration of 50 ppm CD-3 in aqueous solution compared to 65.0 mg/g of NaY and 48.2 mg/g for NH4Y synthetic zeolites corresponding to the removal of CD-3 from 120 to 2001 of 50 ppm aqueous solution per kg of natural zeoliferous tuff; this capacity is only 6-10 times lower than type-Y synthetic zeolite. Initial rates of uptake are 20.8 mg/l/min for natural and 38.5 mg/l/min for synthetic zeolites. Regeneration levels of 55, 23, 35, and 33% are obtained for MCH, SF, NaY, and NH4Y, respectively. The rapid and almost complete uptake of CD-3 from its aqueous solutions at low CD-3 concentrations by the natural zeolites is promising for such an application.

Biosorption of cadmium and lead from aqueous solution by fresh water alga Anabaena sphaerica biomass.

PubMed

Abdel-Aty, Azza M; Ammar, Nabila S; Abdel Ghafar, Hany H; Ali, Rizka K

2013-07-01

The present work represents the biosorption of Cd(II) and Pb(II) from aqueous solution onto the biomass of the blue green alga Anabaena sphaerica as a function of pH, biosorbent dosage, contact time, and initial metal ion concentrations. Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of both metals by A. sphaerica biomass. The biosorption isotherms studies indicated that the biosorption of Cd(II) and Pb(II) follows the Langmuir and Freundlish models. The maximum biosorption capacities (qmax ) were 111.1 and 121.95 mg/g, respectively, at the optimum conditions for each metal. From the D-R isotherm model, the mean free energy was calculated to be 11.7 and 14.3 kJ/mol indicating that the biosorption mechanism of Cd(II) and Pb(II) by A. sphaerica was chemisorption. The FTIR analysis for surface function group of algal biomass revealed the existence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for the biosorption of Cd(II) and Pb(II). The results suggested that the biomass of A. sphaerica is an extremely efficient biosorbent for the removal of Cd(II) and Pb(II) from aqueous solutions.

Biosorption of cadmium and lead from aqueous solution by fresh water alga Anabaena sphaerica biomass

PubMed Central

Abdel -Aty, Azza M.; Ammar, Nabila S.; Abdel Ghafar, Hany H.; Ali, Rizka K.

2012-01-01

The present work represents the biosorption of Cd(II) and Pb(II) from aqueous solution onto the biomass of the blue green alga Anabaena sphaerica as a function of pH, biosorbent dosage, contact time, and initial metal ion concentrations. Freundlich, Langmuir, and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherm of both metals by A. sphaerica biomass. The biosorption isotherms studies indicated that the biosorption of Cd(II) and Pb(II) follows the Langmuir and Freundlish models. The maximum biosorption capacities (qmax) were 111.1 and 121.95 mg/g, respectively, at the optimum conditions for each metal. From the D–R isotherm model, the mean free energy was calculated to be 11.7 and 14.3 kJ/mol indicating that the biosorption mechanism of Cd(II) and Pb(II) by A. sphaerica was chemisorption. The FTIR analysis for surface function group of algal biomass revealed the existence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for the biosorption of Cd(II) and Pb(II). The results suggested that the biomass of A. sphaerica is an extremely efficient biosorbent for the removal of Cd(II) and Pb(II) from aqueous solutions. PMID:25685442

Reclamation of cadmium-contaminated soil using dissolved organic matter solution originating from wine-processing waste sludge.

PubMed

Liu, Cheng-Chung; Chen, Guan-Bu

2013-01-15

Soil washing using an acid solution is a common practice for removing heavy metals from contaminated soil in Taiwan. However, serious loss of nutrients from soil is a major drawback of the washing. Distillery sludge can be used to prepare a dissolved organic matter (DOM) solution by extracting its organic constituents with alkaline solutions. This study employed DOM solutions to remediate Cd-contaminated soil (with concentrations up to 21.5 mg kg(-1)) and determine the factors affecting removal of Cd, such as pH, initial concentration of DOM solution, temperature, and washing frequency. When washing with pH 3.0 and 1250 mg L(-1) DOM solution, about 80% and 81% of Cd were removed from the topsoil at 27 °C and subsoil at 40 °C, respectively. To summarize the changes in fertility during DOM washing with various pH solutions: the increase in organic matter content ranged from 7.7% to 23.7%; cation exchange capacity (CEC) ranged from 4.6% to 13.9%; available ammonium (NNH(4)) content ranged from 39.4% to 2175%; and available phosphorus content ranged from 34.5% to 182%. Exchangeable K, Ca, and Mg remained in the topsoil after DOM washing, with concentrations of 1.1, 2.4, and 1.5 times higher than those treated with HCl solution at the same pH, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

Reducement of cadmium adsorption on clay minerals by the presence of dissolved organic matter from animal manure.

PubMed

Zhou, Wenjun; Ren, Lingwei; Zhu, Lizhong

2017-04-01

Clay minerals are the most popular adsorbents/amendments for immobilizing heavy metals in contaminated soils, but the dissolved organic matter (DOM) in soil environment would potentially affect the adsorption/immobilization capacity of clay minerals for heavy metals. In this study, the effects of DOM derived from chicken manure (CM) on the adsorption of cadmium (Cd 2+ ) on two clay minerals, bentonite and zeolite, were investigated. The equilibrium data for Cd 2+ sorption in the absence or presence of CM-DOM could be well-fitted to the Langmuir equation (R 2  > 0.97). The presence of CM-DOM in the aqueous solution was found to greatly reduce the adsorption capacity of both minerals for Cd 2+ , in particular zeolite, and the percentage decreases for Cd 2+ sorption increased with increasing concentrations of Cd 2+ as well as CM-DOM in aqueous solutions. The adsorption of CM-DOM on zeolite was greater than that on bentonite in the absence of Cd 2+ , however, a sharp increase was observed for CM-DOM sorption on bentonite with increasing Cd 2+ concentrations but little change for that on zeolite, which can be attributed to the different ternary structures on mineral surface. The CM-DOM modified clay minerals were utilized to investigate the effect of mineral-adsorbed CM-DOM on Cd 2+ sorption. The adsorbed form was found to inhibit Cd 2+ sorption, and further calculation suggested it primarily responsible for the overall decrease in Cd 2+ sorption on clay minerals in the presence of CM-DOM in aqueous solutions. An investigation for the mineral surface morphology suggested that the mineral-adsorbed CM-DOM decreased Cd 2+ sorption on bentonite mainly through barrier effect, while in the case of zeolite, it was the combination of active sites occupation and barrier effect. These results can serve as a guide for evaluating the performance of clay minerals in immobilizing heavy metals when animal manure is present in contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

The influence of EDTA application on the interactions of cadmium, zinc, and lead and their uptake of rainbow pink (Dianthus chinensis).

PubMed

Lai, Hung-Yu; Chen, Zueng-Sang

2006-10-11

Soil used in this study was artificially contaminated with Cd, Zn, Pb, or applied in combinations (Cd-Zn, Cd-Pb, Zn-Pb, or Cd-Zn-Pb) to study the interactions of metals in soil contaminated with multiple metals. After planting rainbow pink (Dianthus chinensis) in these soils for 21 days, three different concentrations of ethylenedinitrilotetraacetic acid (EDTA) solutions were added to study the effect of applying EDTA on the interactions among these metals. The concentrations of Cd, Zn, and Pb in the soil solutions of different metals-treated soils increased significantly after applying 5 mmol EDTA kg(-1) soil (p<0.05). The potential of groundwater contamination will increase after applying EDTA and it is not recommended to be in situ used or have to use very carefully. The existence of Pb in the Cd-contaminated soil enhanced the uptake of Cd in rainbow pink in the treatments of control and 2 mmol EDTA kg(-1) soil. Cadmium inhibited the concentration of Zn without applying EDTA. However, whether the application of EDTA or not and the applied EDTA concentration had the greatest effect on the uptake of Pb when compared to Cd and Zn. After applying 5 mmol EDTA kg(-1) soil, Cd or Zn in the Pb-contaminated soil inhibited the uptake of Pb in rainbow pink, but there were no effect in other treatments.

Digital terrain modelling and industrial surface metrology - Converging crafts

USGS Publications Warehouse

Pike, R.J.

2001-01-01

Quantitative characterisation of surface form, increasingly from digital 3-D height data, is cross-disciplinary and can be applied at any scale. Thus, separation of industrial-surface metrology from its Earth-science counterpart, (digital) terrain modelling, is artificial. Their growing convergence presents an opportunity to develop in surface morphometry a unified approach to surface representation. This paper introduces terrain modelling and compares it with metrology, noting their differences and similarities. Examples of potential redundancy among parameters illustrate one of the many issues common to both disciplines. ?? 2001 Elsevier Science Ltd. All rights reserved.

NASA metrology and calibration, 1993

NASA Technical Reports Server (NTRS)

1993-01-01

Th sixteenth annual workshop of NASA's Metrology and Calibration Working Group was held April 20-22, 1993. The goals of the Working Group are to provide Agencywide standardization of individual metrology programs, where appropriate; to promote cooperation and exchange of information within NASA, with other Government agencies, and with industry; to serve as the primary Agency interface with the National Institute of Standards and Technology; and to encourage formal quality control techniques such as Measurement Assurance Programs. These proceedings contain unedited reports and presentations from the workshop and are provided for information only.

Functionalized CdS quantum dots-based luminescence probe for detection of heavy and transition metal ions in aqueous solution.

PubMed

Chen, Jinlong; Zheng, Aifang; Gao, Yingchun; He, Chiyang; Wu, Genhua; Chen, Youcun; Kai, Xiaoming; Zhu, Changqing

2008-03-01

Strong luminescence CdS quantum dots (QDs) have been prepared and modified with l-cysteine by a facile seeds-assistant technique in water. They are water-soluble and highly stable in aqueous solution. CdS QDs evaluated as a luminescence probe for heavy and transition metal (HTM) ions in aqueous solution was systematically studied. Five HTM ions such as silver(I) ion, copper(II) ion, mercury(II) ion, cobalt(II) ion, and nickel(II) ion significantly influence the photophysics of the emission from the functionalized CdS QDs. Experiment results showed that the fluorescence emission from CdS QDs was enhanced significantly by silver ion without any spectral shift, while several other bivalent HTM ions, such as Hg(2+), Cu(2+), Co(2+), and Ni(2+), exhibited effective optical quenching effect on QDs. Moreover, an obvious red-shift of emission band was observed in the quenching of CdS QDs for Hg(2+) and Cu(2+) ions. Under the optimal conditions, the response was linearly proportional to the concentration of Ag(+) ion ranging from 1.25 x 10(-7) to 5.0 x 10(-6)molL(-1) with a detection limit of 2.0 x 10(-8)molL(-1). The concentration dependence of the quenching effect on functionalized QDs for the other four HTM ions could be well described by typical Stern-Volmer equation, with the linear response of CdS QDs emission proportional to the concentration ranging from 1.50 x 10(-8) to 7.50 x 10(-7)molL(-1) for Hg(2+) ion, 3.0 x 10(-7) to 1.0 x 10(-5)molL(-1) for Ni(2+) ion, 4.59 x 10(-8) to 2.295 x 10(-6)molL(-1) for Cu(2+) ion, and 1.20 x 10(-7) to 6.0 x 10(-6)molL(-1) Co(2+) ion, respectively. Based on the distinct optical properties of CdS QDs system with the five HTM ions, and the relatively wide linear range and rapid response to HTM ions, CdS QDs can be developed as a potential identified luminescence probe for familiar HTM ions detection in aqueous solution.

In-situ sensing using mass spectrometry and its use for run-to-run control on a W-CVD cluster tool

NASA Astrophysics Data System (ADS)

Gougousi, T.; Sreenivasan, R.; Xu, Y.; Henn-Lecordier, L.; Rubloff, G. W.; Kidder, , J. N.; Zafiriou, E.

2001-01-01

A 300 amu closed-ion-source RGA (Leybold-Inficon Transpector 2) sampling gases directly from the reactor of an ULVAC ERA-1000 cluster tool has been used for real time process monitoring of a W CVD process. The process involves H2 reduction of WF6 at a total pressure of 67 Pa (0.5 torr) to produce W films on Si wafers heated at temperatures around 350 °C. The normalized RGA signals for the H2 reagent depletion and the HF product generation were correlated with the W film weight as measured post-process with an electronic microbalance for the establishment of thin-film weight (thickness) metrology. The metrology uncertainty (about 7% for the HF product) was limited primarily by the very low conversion efficiency of the W CVD process (around 2-3%). The HF metrology was then used to drive a robust run-to-run control algorithm, with the deposition time selected as the manipulated (or controlled) variable. For that purpose, during a 10 wafer run, a systematic process drift was introduced as a -5 °C processing temperature change for each successive wafer, in an otherwise unchanged process recipe. Without adjustment of the deposition time the W film weight (thickness) would have declined by about 50% by the 10th wafer. With the aid of the process control algorithm, an adjusted deposition time was computed so as to maintain constant HF sensing signal, resulting in weight (thickness) control comparable to the accuracy of the thickness metrology. These results suggest that in-situ chemical sensing, and particularly mass spectrometry, provide the basis for wafer state metrology as needed to achieve run-to-run control. Furthermore, since the control accuracy was consistent with the metrology accuracy, we anticipate significant improvements for processes as used in manufacturing, where conversion rates are much higher (40-50%) and corresponding signals for metrology will be much larger.

The CdCl2 effects on synthetic DNAs encaged in the nanodomains of a cationic water-in-oil microemulsion.

PubMed

Airoldi, Marta; Gennaro, Giuseppe; Giomini, Marcello; Giuliani, Anna Maria; Giustini, Mauro; Palazzo, Gerardo

2011-07-14

The present work is dedicated to the study of the interactions of CdCl(2) with the synthetic polynucleotides polyAT and polyGC confined in the nanoscopic aqueous compartment of the water-in-oil microemulsion CTAB/pentanol/hexane/water, with the goal to mimic in vitro the situation met by the nucleic acids in vivo. In biological structures, in fact, very long strings of nucleic acids are segregated into very small compartments having a radius exceedingly smaller than the length of the encapsulated macromolecule. For comparison, the behaviour of polyGC was also studied in aqueous solutions of matched composition. The conformational and thermal stabilities of both polynucleotides enclosed in the inner compartment of the microemulsion are scarcely affected by the presence of CdCl(2), whereas in solution immediate and large effects were observed also at room temperature. The lack of effects of CdCl(2) on the properties of the biopolymers entrapped in the aqueous core of the microemulsion has been attributed to the peculiar characteristics of the medium (low dielectric constant, in particular) which cause a total repression of the CdCl(2) dissociation that is not complete even in water. In fact, several of the numerous effects of CdCl(2) observed on the conformational stability of polyGC in aqueous solutions have also been ascribed to the limited dissociation of the cadmium salt.

Poly(hydroxyethyl methacrylate-co-methacryloylglutamic acid) nanospheres for adsorption of Cd2+ ions from aqueous solutions

NASA Astrophysics Data System (ADS)

Esen, Cem; Şenay, Raziye Hilal; Feyzioğlu, Esra; Akgöl, Sinan

2014-02-01

Poly(2-hydroxyethyl methacrylate-co- N-methacryloyl-( l)-glutamic acid) p(HEMA-MAGA) nanospheres have been synthesized, characterized, and used for the adsorption of Cd2+ ions from aqueous solutions. Nanospheres were prepared by surfactant free emulsion polymerization. The p(HEMA-MAGA) nanospheres were characterized by SEM, FTIR, zeta size, and elemental analysis. The specific surface area of nanospheres was found to be 1,779 m2/g. According to zeta size analysis results, average size of nanospheres is 147.3 nm with poly-dispersity index of 0.200. The goal of this study was to evaluate the adsorption performance of p(HEMA-MAGA) nanospheres for Cd2+ ions from aqueous solutions by a series of batch experiments. The Cd2+ concentration was determined by inductively coupled plasma-optical emission spectrometer. Equilibrium sorption experiments indicated a Cd2+ uptake capacity of 44.2 mg g-1 at pH 4.0 at 25 °C. The adsorption of Cd2+ ions increased with increasing pH and reached a plateau value at around pH 4.0. The data were successfully modeled with a Langmuir equation. A series of kinetics experiments was then carried out and a pseudo-second order equation was used to fit the experimental data. Desorption experiments which were carried out with nitric acid showed that the p(HEMA-MAGA) nanospheres could be reused without significant losses of their initial properties in consecutive adsorption and elution operations.

The effect of operational parameters on the photocatalytic degradation of Congo red organic dye using ZnO-CdS core-shell nano-structure coated on glass by Doctor Blade method.

PubMed

Habibi, Mohammad Hossein; Rahmati, Mohammad Hossein

2015-02-25

Photocatalytic degradation of Congo red was investigated using ZnO-CdS core-shell nano-structure coated on glass by Doctor Blade method in aqueous solution under irradiation. Field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques were used for the morphological and structural characterization of ZnO-CdS core-shell nanostructures. XRD results showed diffractions of wurtzite zinc oxide core and wurtzite cadmium sulfide shell. FESEM results showed that nanoparticles are nearly hexagonal with an average diameter of about 50 nm. The effect of catalyst loading, UV-light irradiation time and solution pH on photocatalytic degradation of Congo red was studied and optimized values were obtained. Results showed that the employment of efficient photocatalyst and selection of optimal operational parameters may lead to complete decolorization of dye solutions. It was found that ZnO-CdS core-shell nano-structure is more favorable for the degradation of Congo red compare to pure ZnO or pure CdS due to lower electron hole recombination. The results showed that the photocatalytic degradation rate of Congo red is enhanced with increasing the content of ZnO up to ZnO(0.2 M)/CdS(0.075 M) which is reached 88.0% within 100 min irradiation. Copyright © 2014 Elsevier B.V. All rights reserved.

CD and defect improvement challenges for immersion processes

NASA Astrophysics Data System (ADS)

Ehara, Keisuke; Ema, Tatsuhiko; Yamasaki, Toshinari; Nakagawa, Seiji; Ishitani, Seiji; Morita, Akihiko; Kim, Jeonghun; Kanaoka, Masashi; Yasuda, Shuichi; Asai, Masaya

2009-03-01

The intention of this study is to develop an immersion lithography process using advanced track solutions to achieve world class critical dimension (CD) and defectivity performance in a state of the art manufacturing facility. This study looks at three important topics for immersion lithography: defectivity, CD control, and wafer backside contamination. The topic of defectivity is addressed through optimization of coat, develop, and rinse processes as well as implementation of soak steps and bevel cleaning as part of a comprehensive defect solution. Develop and rinse processing techniques are especially important in the effort to achieve a zero defect solution. Improved CD control is achieved using a biased hot plate (BHP) equipped with an electrostatic chuck. This electrostatic chuck BHP (eBHP) is not only able to operate at a very uniform temperature, but it also allows the user to bias the post exposure bake (PEB) temperature profile to compensate for systematic within-wafer (WiW) CD non-uniformities. Optimized CD results, pre and post etch, are presented for production wafers. Wafer backside particles can cause focus spots on an individual wafer or migrate to the exposure tool's wafer stage and cause problems for a multitude of wafers. A basic evaluation of the cleaning efficiency of a backside scrubber unit located on the track was performed as a precursor to a future study examining the impact of wafer backside condition on scanner focus errors as well as defectivity in an immersion scanner.

Phytoremediation potential of Cd and Zn by wetland plants, Colocasia esculenta L. Schott., Cyperus malaccensis Lam. and Typha angustifolia L. grown in hydroponics.

PubMed

Chayapan, P; Kruatrachue, M; Meetam, M; Pokethitiyook, P

2015-09-01

Cadmium and zinc phytoremediation potential of wetland plants, Colocasia esculenta, Cyperus malaccensis, and Typha angustifolia, was investigated. Plants were grown for 15 days in nutrient solutions containing various concentrations of Cd (0, 5, 10, 20, 50 mg l(-1)) and Zn (0, 10, 20, 50, 100 mg l(-1)). T angustifolia was tolerant to both metals as indicated by high RGR when grown in 50 mg I(-1) Cd and 100 mg I(-1) Zn solutions. All these plants accumulated more metals in their underground parts and > 100 mg kg(-1) in their aboveground with TF values < 1. Only C. esculenta could be considered a Zn hyperaccumulator because it could concentrate > 10,000 mg kg(-1) in its aboveground parts with TF > 1. T angustifolia exhibited highest biomass production and highest Cd and Zn uptake, confirming that this plant is a suitable candidate for treating of Cd contaminated soil/sediments.

Comparative study on kinetic adsorption of Cu(II), Cd(II) and Ni(II) ions from aqueous solutions using activated sludge and dried sludge

NASA Astrophysics Data System (ADS)

Ong, Soon-An; Toorisaka, Eiichi; Hirata, Makoto; Hano, Tadashi

2013-03-01

The adsorption of Cu(II), Cd(II) and Ni(II) ions from aqueous solutions by activated sludge and dried sludge was investigated under laboratory conditions to assess its potential in removing metal ions. The adsorption behavior of metal ions onto activated sludge and dried sludge was analyzed with Weber-Morris intra-particle diffusion model, Lagergren first-order model and pseudo second-order model. The rate constant of intra-particle diffusion on activated sludge and dried sludge increased in the sequence of Cu(II) > Ni(II) > Cd(II). According to the regression coefficients, it was observed that the kinetic adsorption data can fit better by the pseudo second-order model compared to the first-order Lagergren model with R 2 > 0.997. The adsorption capacities of metal ions onto activated sludge and dried sludge followed the sequence Ni(II) ≈ Cu(II) > Cd(II) and Cu(II) > Ni(II) > Cd(II).

NPL scoops £25m for advanced metrology centre

NASA Astrophysics Data System (ADS)

Singh Chadha, Kulvinder

2013-03-01

The National Physical Laboratory (NPL) in Teddington, UK, is to receive £25m towards the construction of an Advanced Metrology Laboratory (AML) that will contain up to 20 labs and be complete by 2017.

Technique for the metrology calibration of a Fourier transform spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spencer, Locke D.; Naylor, David A

2008-11-10

A method is presented for using a Fourier transform spectrometer (FTS) to calibrate the metrology of a second FTS. This technique is particularly useful when the second FTS is inside a cryostat or otherwise inaccessible.

Combined dry plasma etching and online metrology for manufacturing highly focusing x-ray mirrors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berujon, S., E-mail: berujon@esrf.eu; Ziegler, E., E-mail: ziegler@esrf.eu; Cunha, S. da

A new figuring station was designed and installed at the ESRF beamline BM05. It allows the figuring of mirrors within an iterative process combining the advantage of online metrology with dry etching. The complete process takes place under a vacuum environment to minimize surface contamination while non-contact surfacing tools open up the possibility of performing at-wavelength metrology and eliminating placement errors. The aim is to produce mirrors whose slopes do not deviate from the stigmatic profile by more than 0.1 µrad rms while keeping surface roughness in the acceptable limit of 0.1-0.2 nm rms. The desired elliptical mirror surface shapemore » can be achieved in a few iterations in about a one day time span. This paper describes some of the important aspects of the process regarding both the online metrology and the etching process.« less

Feasibility of phytoextraction to remediate cadmium and zinc contaminated soils.

PubMed

Koopmans, G F; Römkens, P F A M; Fokkema, M J; Song, J; Luo, Y M; Japenga, J; Zhao, F J

2008-12-01

A Cd and Zn contaminated soil was mixed and equilibrated with an uncontaminated, but otherwise similar soil to establish a gradient in soil contamination levels. Growth of Thlaspi caerulescens (Ganges ecotype) significantly decreased the metal concentrations in soil solution. Plant uptake of Cd and Zn exceeded the decrease of the soluble metal concentrations by several orders of magnitude. Hence, desorption of metals must have occurred to maintain the soil solution concentrations. A coupled regression model was developed to describe the transfer of metals from soil to solution and plant shoots. This model was applied to estimate the phytoextraction duration required to decrease the soil Cd concentration from 10 to 0.5 mg kg(-1). A biomass production of 1 and 5 t dm ha(-1) yr(-1) yields a duration of 42 and 11 yr, respectively. Successful phytoextraction operations based on T. caerulescens require an increased biomass production.

Research on mechanical properties of silver-bearing antibacterial duplex stainless steel

NASA Astrophysics Data System (ADS)

Liu, Dong; Xiang, Hongliang

2017-04-01

In this paper, silver-bearing antibacterial duplex stainless steels were prepared by adding Ag or Cu-Ag alloy particles. The microstructure, mechanical properties and fracture morphology were investigated in detail by OM, ESEM and tensile testing machine. Tensile tests indicate that the tensile fractures of Ag-bearing antibacterial duplex stainless steel and CD4MCu have the typical ductile character and toughening nests are isometric. After the solution treatment at 1050 ℃, for the material prepared by adding 150-300 µm Cu-Ag master alloy after the solution treatment at 1050 ℃, its plasticity is superior to that of CD4MCu, the strength and hardness are equivalent. But for the material prepared by adding pure Ag alloy particles, its plasticity, strength and hardness are less than that of CD4MCu. When the solution temperature rises, the plastic, strength and hardness of the material prepared by adding 150-300 µm Cu-Ag decrease.

Rapid adsorption of Pb, Cu and Cd from aqueous solutions by β-cyclodextrin polymers

NASA Astrophysics Data System (ADS)

He, Junyong; Li, Yulian; Wang, Chengming; Zhang, Kaisheng; Lin, Dongyue; Kong, Lingtao; Liu, Jinhuai

2017-12-01

Removing heavy metals from aqueous solutions has drawn more and more attentions these years because of their serious global health challenge to human society. To develop an adsorbent with low-cost and high-efficiency for removal of heavy metals (HMs), β-cyclodextrin (β-CD) polymers crosslinked with rigid aromatic groups were prepared and used for lead (Pb), copper (Cu) and cadmium (Cd) removal for the first time. The negatively charged β-CD polymers with large BET surface area were suitable to be used in HMs adsorption. The adsorption process completed in 5 min was well fit by Freundlich isotherm model and pseudo-second-order model. The intraparticle diffusion model was also appropriate to describe the adsorption of Pb, Cu and Cd on β-CD polymer. The maximum of adsorption capacities at 25 °C for Pb, Cu and Cd were 196.42, 164.43 and 136.43 mg/g when the initial concentration was 200 mg/L. The HMs adsorption process on the surface of β-CD polymer was an endothermic and spontaneous process. Both of the electrostatic interaction and distribution of Pb, Cu and Cd species influenced the adsorption process at different pH values. The order of removal efficiencies in multi-component adsorption for the three metal ions were Pb > Cu > Cd. The adsorption mechanisms were H+ ions on hydroxyl groups exchanged with heavy metal ions and electrostatic interactions. This study indicated that β-CD polymers could be developed into effective adsorbents for rapid removal of heavy metals.

Metal-immobilizing Serratia liquefaciens CL-1 and Bacillus thuringiensis X30 increase biomass and reduce heavy metal accumulation of radish under field conditions.

PubMed

Han, Hui; Sheng, Xiafang; Hu, Jingwen; He, Linyan; Wang, Qi

2018-06-18

In this study, metal-tolerant bacteria Serratia liquefaciens CL-1 and Bacillus thuringiensis X30 were compared for their Cd and Pb immobilization in solution and impacts on biomass and Cd and Pb uptake in a radish in metal-contaminated soils under field conditions. Strains CL-1 and X30 significantly reduced water-soluble Cd and Pb concentrations (45-67%) and increased the pH in solution compared to the controls. These strains significantly increased the biomass (25-99%) and decreased edible tissue Cd and Pb uptake in the radish (37-81%) and DTPA-extractable Cd and Pb contents (18-44%) of the rhizosphere soil compared to the un-inoculated controls. Strain CL-1 had higher potential to reduce edible tissue Cd and Pb uptake in the radish and DTPA-extractable Cd content than strain X30. Also, these strains significantly increased Cd translocation factor and strain CL-1 also significantly increased Pb translocation factor of the radish. Furthermore, strain CL-1 significantly increased the ratio of small soil aggregates (< 0.25 mm and 0.25-0.50 mm) of the rhizosphere soil. The results showed that these strains reduced the edible tissue Cd and Pb uptake through decreasing Cd and Pb availability in the soil and increasing Cd or Pb translocation from the roots to the leaves of the radish. The results also suggested the bacteria-related differences in reduced heavy metal uptake in the radish and the mechanisms involved under field conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

Metrology requirements for the serial production of ELT primary mirror segments

NASA Astrophysics Data System (ADS)

Rees, Paul C. T.; Gray, Caroline

2015-08-01

The manufacture of the next generation of large astronomical telescopes, the extremely large telescopes (ELT), requires the rapid manufacture of greater than 500 1.44m hexagonal segments for the primary mirror of each telescope. Both leading projects, the Thirty Meter Telescope (TMT) and the European Extremely Large Telescope (E-ELT), have set highly demanding technical requirements for each fabricated segment. These technical requirements, when combined with the anticipated construction schedule for each telescope, suggest that more than one optical fabricator will be involved in the delivery of the primary mirror segments in order to meet the project schedule. For one supplier, the technical specification is challenging and requires highly consistent control of metrology in close coordination with the polishing technologies used in order to optimize production rates. For production using multiple suppliers, however the supply chain is structured, consistent control of metrology along the supply chain will be required. This requires a broader pattern of independent verification than is the case of a single supplier. This paper outlines the metrology requirements for a single supplier throughout all stages of the fabrication process. We identify and outline those areas where metrology accuracy and duration have a significant impact on production efficiency. We use the challenging ESO E-ELT technical specification as an example of our treatment, including actual process data. We further develop this model for the case of a supply chain consisting of multiple suppliers. Here, we emphasize the need to control metrology throughout the supply chain in order to optimize net production efficiency.

High throughput wafer defect monitor for integrated metrology applications in photolithography

NASA Astrophysics Data System (ADS)

Rao, Nagaraja; Kinney, Patrick; Gupta, Anand

2008-03-01

The traditional approach to semiconductor wafer inspection is based on the use of stand-alone metrology tools, which while highly sensitive, are large, expensive and slow, requiring inspection to be performed off-line and on a lot sampling basis. Due to the long cycle times and sparse sampling, the current wafer inspection approach is not suited to rapid detection of process excursions that affect yield. The semiconductor industry is gradually moving towards deploying integrated metrology tools for real-time "monitoring" of product wafers during the manufacturing process. Integrated metrology aims to provide end-users with rapid feedback of problems during the manufacturing process, and the benefit of increased yield, and reduced rework and scrap. The approach of monitoring 100% of the wafers being processed requires some trade-off in sensitivity compared to traditional standalone metrology tools, but not by much. This paper describes a compact, low-cost wafer defect monitor suitable for integrated metrology applications and capable of detecting submicron defects on semiconductor wafers at an inspection rate of about 10 seconds per wafer (or 360 wafers per hour). The wafer monitor uses a whole wafer imaging approach to detect defects on both un-patterned and patterned wafers. Laboratory tests with a prototype system have demonstrated sensitivity down to 0.3 µm on un-patterned wafers and down to 1 µm on patterned wafers, at inspection rates of 10 seconds per wafer. An ideal application for this technology is preventing photolithography defects such as "hot spots" by implementing a wafer backside monitoring step prior to exposing wafers in the lithography step.

Metrology to quantify wear and creep of polyethylene tibial knee inserts.

PubMed

Muratoglu, Orhun K; Perinchief, Rebecca S; Bragdon, Charles R; O'Connor, Daniel O; Konrad, Reto; Harris, William H

2003-05-01

Assessment of damage on articular surfaces of ultrahigh molecular weight polyethylene tibial knee inserts primarily has been limited to qualitative methods, such as visual observation and classification of features such as pitting, delamination, and subsurface cracking. Semiquantitative methods also have been proposed to determine the linear penetration and volume of the scar that forms on articular surfaces of tibial knee inserts. The current authors report a new metrologic method that uses a coordinate measuring machine to quantify the dimensions of this scar. The articular surface of the insert is digitized with the coordinate measuring machine before and after regular intervals of testing on a knee simulator. The volume and linear penetration of the scar are calculated by mathematically taking the difference between the digitized surface maps of the worn and unworn articular surfaces. Three conventional polyethylene tibial knee inserts of a posterior cruciate-sparing design were subjected to five million cycles of normal gait on a displacement-driven knee wear simulator in bovine serum. A metrologic method was used to calculate creep and wear contributions to the scar formation on each tibial plateau. Weight loss of the inserts was determined gravimetrically with the appropriate correction for fluid absorption. The total average wear volume was 43 +/- 9 and 41 +/- 4 mm3 measured by the metrologic and gravimetric methods, respectively. The wear rate averaged 8.3 +/- 0.9 and 8.5 +/- 1.6 mm3 per million cycles measured by the metrologic and gravimetric methods, respectively. These comparisons reflected strong agreement between the metrologic and gravimetric methods.

Study of the Spectral Properties of Nanocomposites with CdSe Quantum Dots in a Wide Range of Low Temperatures

NASA Astrophysics Data System (ADS)

Magaryan, K. A.; Eremchev, I. Y.; Karimullin, K. R.; Knyazev, M. V.; Mikhailov, M. A.; Vasilieva, I. A.; Klimusheva, G. V.

2015-09-01

Luminescence spectra of the colloidal solution of CdSe quantum dots (in toluene) were studied in a wide range of low temperatures. Samples were synthesized in the liquid crystal matrix of cadmium octanoate (CdC8). A comparative analysis of the obtained data with previous results was performed.

Real cell overlay measurement through design based metrology

NASA Astrophysics Data System (ADS)

Yoo, Gyun; Kim, Jungchan; Park, Chanha; Lee, Taehyeong; Ji, Sunkeun; Jo, Gyoyeon; Yang, Hyunjo; Yim, Donggyu; Yamamoto, Masahiro; Maruyama, Kotaro; Park, Byungjun

2014-04-01

Until recent device nodes, lithography has been struggling to improve its resolution limit. Even though next generation lithography technology is now facing various difficulties, several innovative resolution enhancement technologies, based on 193nm wavelength, were introduced and implemented to keep the trend of device scaling. Scanner makers keep developing state-of-the-art exposure system which guarantees higher productivity and meets a more aggressive overlay specification. "The scaling reduction of the overlay error has been a simple matter of the capability of exposure tools. However, it is clear that the scanner contributions may no longer be the majority component in total overlay performance. The ability to control correctable overlay components is paramount to achieve the desired performance.(2)" In a manufacturing fab, the overlay error, determined by a conventional overlay measurement: by using an overlay mark based on IBO and DBO, often does not represent the physical placement error in the cell area of a memory device. The mismatch may arise from the size or pitch difference between the overlay mark and the cell pattern. Pattern distortion, caused by etching or CMP, also can be a source of the mismatch. Therefore, the requirement of a direct overlay measurement in the cell pattern gradually increases in the manufacturing field, and also in the development level. In order to overcome the mismatch between conventional overlay measurement and the real placement error of layer to layer in the cell area of a memory device, we suggest an alternative overlay measurement method utilizing by design, based metrology tool. A basic concept of this method is shown in figure1. A CD-SEM measurement of the overlay error between layer 1 and 2 could be the ideal method but it takes too long time to extract a lot of data from wafer level. An E-beam based DBM tool provides high speed to cover the whole wafer with high repeatability. It is enabled by using the design as a reference for overlay measurement and a high speed scan system. In this paper, we have demonstrated that direct overlay measurement in the cell area can distinguish the mismatch exactly, instead of using overlay mark. This experiment was carried out for several critical layer in DRAM and Flash memory, using DBM(Design Based Metrology) tool, NGR2170™.

Complexation of polyoxometalates with cyclodextrins.

PubMed

Wu, Yilei; Shi, Rufei; Wu, Yi-Lin; Holcroft, James M; Liu, Zhichang; Frasconi, Marco; Wasielewski, Michael R; Li, Hui; Stoddart, J Fraser

2015-04-01

Although complexation of hydrophilic guests inside the cavities of hydrophobic hosts is considered to be unlikely, we demonstrate herein the complexation between γ- and β-cyclodextrins (γ- and β-CDs) with an archetypal polyoxometalate (POM)--namely, the [PMo12O40](3-) trianion--which has led to the formation of two organic-inorganic hybrid 2:1 complexes, namely [La(H2O)9]{[PMo12O40]⊂[γ-CD]2} (CD-POM-1) and [La(H2O)9] {[PMo12O40]⊂[β-CD]2} (CD-POM-2), in the solid state. The extent to which these complexes assemble in solution has been investigated by (i) (1)H, (13)C, and (31)P NMR spectroscopies and (ii) small- and wide-angle X-ray scattering, as well as (iii) mass spectrometry. Single-crystal X-ray diffraction reveals that both complexes have a sandwich-like structure, wherein one [PMo12O40](3-) trianion is encapsulated by the primary faces of two CD tori through intermolecular [C-H···O═Mo] interactions. X-ray crystal superstructures of CD-POM-1 and CD-POM-2 show also that both of these 2:1 complexes are lined up longitudinally in a one-dimensional columnar fashion by means of [O-H···O] interactions. A beneficial nanoconfinement-induced stabilizing effect is supported by the observation of slow color changes for these supermolecules in aqueous solution phase. Electrochemical studies show that the redox properties of [PMo12O40](3-) trianions encapsulated by CDs in the complexes are largely preserved in solution. The supramolecular complementarity between the CDs and the [PMo12O40](3-) trianion provides yet another opportunity for the functionalization of POMs under mild conditions by using host-guest chemistry.

Remediation of cadmium contaminated water and soil using vinegar residue biochar.

PubMed

Li, Yuxin; Pei, Guangpeng; Qiao, Xianliang; Zhu, Yuen; Li, Hua

2018-06-01

This study investigated a new biochar produced from vinegar residue that could be used to remediate cadmium (Cd)-contaminated water and soil. Aqueous solution adsorption and soil incubation experiments were performed to investigate whether a biochar prepared at 700 °C from vinegar residue could efficiently adsorb and/or stabilize Cd in water and soil. In the aqueous solution adsorption experiment, the Cd adsorption process was best fitted by the pseudo-second-order kinetic and Freundlich isotherm models. If the optimum parameters were used, i.e., pH 5 or higher, a biochar dosage of 12 g L -1 , a 10 mg L -1 Cd initial concentration, and 15-min equilibrium time, at 25 °C, then Cd removal could reach about 100%. The soil incubation experiment evaluated the biochar effects at four different application rates (1, 2, 5, and 10% w/w) and three Cd contamination rates (0.5, 1, and 2.5 mg kg -1 ) on soil properties and Cd fractionation. Soil pH and organic matter increased after adding biochar, especially at the 10% application rate. At Cd pollution levels of 1.0 or 2.5 mg kg -1 , a 10% biochar application rate was most effective. At 0.5 mg Cd kg -1 soil, a 5% biochar application rate was most efficient at transforming the acid extractable and easily reducible Cd fractions to oxidizable and residual Cd. The results from this study demonstrated that biochar made from vinegar residue could be a new and promising alternative biomass-derived material for Cd remediation in water and soil.

Characterization of Etch Pit Formation via the Everson-Etching Method on CdZnTe Crystal Surfaces from the Bulk to the Nano-Scale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teague, L.; Duff, M.; Cadieux, J.

2010-09-24

A combination of atomic force microscopy, optical microscopy, and mass spectrometry was employed to study CdZnTe crystal surface and used etchant solution following exposure of the CdZnTe crystal to the Everson etch solution. We discuss the results of these studies in relationship to the initial surface preparation methods, the performance of the crystals as radiation spectrometers, the observed etch pit densities, and the chemical mechanism of surface etching. Our results show that the surface features that are exposed to etchants result from interactions with the chemical components of the etchants as well as pre-existing mechanical polishing.

Determination of the spectral values of the real part of the relative refractive index of human blood erythrocytes from the measured directional scattering coefficients

NASA Astrophysics Data System (ADS)

Kugeiko, M. M.; Lisenko, S. A.

2008-07-01

An easily automated method for determining the real part of the refractive index of human blood erythrocytes in the range 0.3 1.2 μm is proposed. The method is operationally and metrologically reliable and is based on the measurement of the coefficients of light scattering from forward and backward hemisphere by two pairs of angles and on the use of multiple regression equations. An engineering solution for constructing a measurement system according to this method is proposed, which makes it possible to maximally reduce the calibration errors and effects of destabilizing factors.

Recent Developments of an Opto-Electronic THz Spectrometer for High-Resolution Spectroscopy

PubMed Central

Hindle, Francis; Yang, Chun; Mouret, Gael; Cuisset, Arnaud; Bocquet, Robin; Lampin, Jean-François; Blary, Karine; Peytavit, Emilien; Akalin, Tahsin; Ducournau, Guillaume

2009-01-01

A review is provided of sources and detectors that can be employed in the THz range before the description of an opto-electronic source of monochromatic THz radiation. The realized spectrometer has been applied to gas phase spectroscopy. Air-broadening coefficients of HCN are determined and the insensitivity of this technique to aerosols is demonstrated by the analysis of cigarette smoke. A multiple pass sample cell has been used to obtain a sensitivity improvement allowing transitions of the volatile organic compounds to be observed. A solution to the frequency metrology is presented and promises to yield accurate molecular line center measurements. PMID:22291552

Pyrometer with tracking balancing

NASA Astrophysics Data System (ADS)

Ponomarev, D. B.; Zakharenko, V. A.; Shkaev, A. G.

2018-04-01

Currently, one of the main metrological noncontact temperature measurement challenges is the emissivity uncertainty. This paper describes a pyrometer with emissivity effect diminishing through the use of a measuring scheme with tracking balancing in which the radiation receiver is a null-indicator. In this paper the results of the prototype pyrometer absolute error study in surfaces temperature measurement of aluminum and nickel samples are presented. There is absolute error calculated values comparison considering the emissivity table values with errors on the results of experimental measurements by the proposed method. The practical implementation of the proposed technical solution has allowed two times to reduce the error due to the emissivity uncertainty.

134Cs emission probabilities determination by gamma spectrometry

NASA Astrophysics Data System (ADS)

de Almeida, M. C. M.; Poledna, R.; Delgado, J. U.; Silva, R. L.; Araujo, M. T. F.; da Silva, C. J.

2018-03-01

The National Laboratory for Ionizing Radiation Metrology (LNMRI/IRD/CNEN) of Rio de Janeiro performed primary and secondary standardization of different radionuclides reaching satisfactory uncertainties. A solution of 134Cs radionuclide was purchased from commercial supplier to emission probabilities determination of some of its energies. 134Cs is a beta gamma emitter with 754 days of half-life. This radionuclide is used as standard in environmental, water and food control. It is also important to germanium detector calibration. The gamma emission probabilities (Pγ) were determined mainly for some energies of the 134Cs by efficiency curve method and the Pγ absolute uncertainties obtained were below 1% (k=1).

Absolute optical metrology : nanometers to kilometers

NASA Technical Reports Server (NTRS)

Dubovitsky, Serge; Lay, O. P.; Peters, R. D.; Liebe, C. C.

2005-01-01

We provide and overview of the developments in the field of high-accuracy absolute optical metrology with emphasis on space-based applications. Specific work on the Modulation Sideband Technology for Absolute Ranging (MSTAR) sensor is described along with novel applications of the sensor.

The high water solubility of inclusion complex of taxifolin-γ-CD prepared and characterized by the emulsion solvent evaporation and the freeze drying combination method.

PubMed

Zu, Yuangang; Wu, Weiwei; Zhao, Xiuhua; Li, Yong; Zhong, Chen; Zhang, Yin

2014-12-30

This study selected γ-cyclodextrin (γ-CD) as the inclusion material and prepared inclusion complex of taxifolin-γ-CD by the emulsion solvent evaporation and the freeze drying combination method to achieve the improvement of the solubility and oral bioavailability of taxifolin. We selected ethyl acetate as the oil phase, deionized water as the water phase. The taxifolin emulsion was prepared using adjustable speed homogenate machine in the process of this experiment, whose particle size was related to the concentration of taxifolin solution, the volume ratio of water phase to oil phase, the speed and time of homogenate. We knew through the single-factor test that, the optimum conditions were: the concentration of taxifolin solution was 40 mg/ml, the volume ratio of water phase to oil phase was 1.5, the speed of homogenate was 5,000 rpm, the homogenate time was 11 min. Taxifolin emulsion with a MPS of 142.5 nm was obtained under the optimum conditions, then the high-concentration taxifolin solution (3mg/ml) was obtained by the rotary evaporation process. Finally, the inclusion complex of taxifolin-γ-CD was prepared by vacuum freeze-dry. The characteristics of the inclusion complex of taxifolin-γ-CD were analyzed using SEM, FTIR, XRD, DSC, and TG. The FTIR results analyzed the interaction of taxifolin and γ-CD and determined the molecular structure of the inclusion complex of taxifolin-γ-CD. The analysis results of XRD, DSC and TG indicated that the inclusion complex of taxifolin-γ-CD was obtained and showed significantly different characteristics with taxifolin. In addition, dissolving capability test, antioxidant capacity test, solvent residue test were also carried out. The experimental datas showed that the solubility of inclusion complex of taxifolin-γ-CD at 25°C and 37°C were about 18.5 times and 19.8 times of raw taxifolin, the dissolution rate of inclusion complex of taxifolin-γ-CD were about 2.84 times of raw taxifolin, the bioavailability of inclusion complex of taxifolin-γ-CD increased 3.72 times compared with raw taxifolin, and the antioxidant capacity of inclusion complex of taxifolin-γ-CD was also superior to raw taxifolin. Furthermore, the amounts of residual solvent of the inclusion complex of taxifolin-γ-CD were suitable for pharmaceutical use. These results suggested that inclusion complex of taxifolin-γ-CD may have potential value to become a new oral taxifolin formulation with high solubility. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis and characterization of Cd Cr and Zn Cd Cr layered double hydroxides intercalated with dodecyl sulfate

NASA Astrophysics Data System (ADS)

Guo, Ying; Zhang, He; Zhao, Lan; Li, Guo-Dong; Chen, Jie-Sheng; Xu, Lin

2005-06-01

Cd-Cr and Zn-Cd-Cr layered double hydroxides (CdCr-LDH and ZnCdCr-LDH) containing alkyl sulfate as the interlamellar anion have been prepared through a coprecipitation technique. The resulting compounds were characterized using X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Magnetic property measurements indicate that antiferromagnetic interactions occur between the chromium ions in the two compounds at low temperatures. The introduction of zinc influences the ligand field of Cr III and the Cr III-Cr III interactions in the LDH compound. It is found that both CdCr-LDH and ZnCdCr-LDH can be delaminated by dispersion in formamide, leading to translucent and stable colloidal solutions.

Metrology laboratory requirements for third-generation synchrotron radiation sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takacs, P.Z.; Quian, Shinan

1997-11-01

New third-generation synchrotron radiation sources that are now, or will soon, come on line will need to decide how to handle the testing of optical components delivered for use in their beam lines. In many cases it is desirable to establish an in-house metrology laboratory to do the work. We review the history behind the formation of the Optical Metrology Laboratory at Brookhaven National Laboratory and the rationale for its continued existence. We offer suggestions to those who may be contemplating setting up similar facilities, based on our experiences over the past two decades.

Metrological Reliability of Medical Devices

NASA Astrophysics Data System (ADS)

Costa Monteiro, E.; Leon, L. F.

2015-02-01

The prominent development of health technologies of the 20th century triggered demands for metrological reliability of physiological measurements comprising physical, chemical and biological quantities, essential to ensure accurate and comparable results of clinical measurements. In the present work, aspects concerning metrological reliability in premarket and postmarket assessments of medical devices are discussed, pointing out challenges to be overcome. In addition, considering the social relevance of the biomeasurements results, Biometrological Principles to be pursued by research and innovation aimed at biomedical applications are proposed, along with the analysis of their contributions to guarantee the innovative health technologies compliance with the main ethical pillars of Bioethics.

Metrology for decommissioning nuclear facilities: Partial outcomes of joint research project within the European Metrology Research Program.

PubMed

Suran, Jiri; Kovar, Petr; Smoldasova, Jana; Solc, Jaroslav; Van Ammel, Raf; Garcia Miranda, Maria; Russell, Ben; Arnold, Dirk; Zapata-García, Daniel; Boden, Sven; Rogiers, Bart; Sand, Johan; Peräjärvi, Kari; Holm, Philip; Hay, Bruno; Failleau, Guillaume; Plumeri, Stephane; Laurent Beck, Yves; Grisa, Tomas

2018-04-01

Decommissioning of nuclear facilities incurs high costs regarding the accurate characterisation and correct disposal of the decommissioned materials. Therefore, there is a need for the implementation of new and traceable measurement technologies to select the appropriate release or disposal route of radioactive wastes. This paper addresses some of the innovative outcomes of the project "Metrology for Decommissioning Nuclear Facilities" related to mapping of contamination inside nuclear facilities, waste clearance measurement, Raman distributed temperature sensing for long term repository integrity monitoring and validation of radiochemical procedures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Albuquerque Regional Training: The Third Seminar on Surface Metrology for the Americas May 12-13 2014

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tran, Sophie M; Tran, Hy D.

The Third Seminar on Surface Metrology for the Americas (SSMA) took place in Albuquerque, New Mexico May 12-13, 2014. The conference was at the Marriott Hotel, in the heart of Albuquerque Uptown, within walking distance of many fantastic restaurants. Why surface metrology? Ask Professor Chris Brown of Worcester Polytechnic Institute (WPI), the chair of the first two SSMAs in 2011 and 2012 and the chair of the ASME B46 committee on classification and designation of surface qualities, and Professor Brown responds: “Because surfaces cover everything.”