Dr. James E. Potzick Profile

Dr. James E. Potzick

Physicist at National Institute of Standards and Technology

SPIE Involvement:

Author | Instructor

Publications (33)

Proceedings Article | 20 April 2011 Paper

TSOM method for semiconductor metrology

Ravikiran Attota, Ronald Dixson, John Kramar, James Potzick, András Vladár, Benjamin Bunday, Erik Novak, Andrew Rudack

Proceedings Volume 7971, 79710T (2011) https://doi.org/10.1117/12.881620

KEYWORDS: Silicon, Overlay metrology, Scanning electron microscopy, Optical microscopes, Metrology, 3D acquisition, 3D metrology, Polarization, 3D modeling, Photomasks

Read Abstract +

Proceedings Article | 2 April 2010 Paper

Metrology and process control: dealing with measurement uncertainty

James Potzick

Proceedings Volume 7638, 76381U (2010) https://doi.org/10.1117/12.851008

KEYWORDS: Tolerancing, Metrology, Image processing, Microscopes, Process control, Standards development, Manufacturing, Photomasks, Feedback loops, Data modeling

Read Abstract +

Proceedings Article | 30 September 2009 Paper

Photomask metrology using a 193nm scatterfield microscope

R. Quintanilha, B. Barnes, Y. Sohn, L. Howard, R. Silver, J. Potzick, M. Stocker

Proceedings Volume 7488, 74881L (2009) https://doi.org/10.1117/12.829693

KEYWORDS: Microscopes, Photomasks, Calibration, Metrology, Ultraviolet radiation, Charge-coupled devices, Standards development, Quartz, Wafer-level optics, Polarization

Read Abstract +

Proceedings Article | 23 September 2009 Paper

Results of an international photomask linewidth comparison of NIST and PTB

B. Bodermann, D. Bergmann, E. Buhr, W. Hässler-Grohne, H. Bosse, J. Potzick, R. Dixson, R. Quintanilha, M. Stocker, A. Vladar, N. Orji

Proceedings Volume 7488, 74881H (2009) https://doi.org/10.1117/12.831373

KEYWORDS: Photomasks, Scanning electron microscopy, Standards development, Metrology, Ultraviolet radiation, Microscopes, Atomic force microscopy, Calibration, Critical dimension metrology, Microscopy

Read Abstract +

Proceedings Article | 23 March 2009 Paper

Image library approach to evaluating parametric uncertainty in metrology of isolated feature width

James Potzick

Proceedings Volume 7272, 727218 (2009) https://doi.org/10.1117/12.815363

KEYWORDS: Photomasks, Microscopes, Metrology, Chromium, Scanning electron microscopy, Calibration, Semiconducting wafers, Optical microscopes, Wafer-level optics, Scatterometry

Read Abstract +

When measuring the width of an isolated line or space on a wafer or photomask, only the feature's image is measured, not the object itself. Often the largest contributors to measurement uncertainty are the uncertainties in the parameters which affect the image. Measurement repeatability is often smaller than the combined parametric uncertainty. An isolated feature's edges are far enough away from nearest edges of other features that its image does not change if this distance is increased (about 10 wavelengths in an optical microscope or exposure tool, or several effective-beam-widths in a SEM). When the leading and trailing edges of the same feature are not isolated from each other the metrology process becomes nonlinear. Isolated features may not be amenable to measurement by grating methods (e.g., scatterometry), and there is no hard lower limit to how small an isolated feature can be measured. There are several ways to infer the size of an isolated feature from its image in a microscope (SEM, AFM, optical,...), and they all require image modeling. Image modeling accounts for the influence of all of the parameters which can affect the image, and relates the apparent linewidth (in the image) to the true linewidth (on the object). The values of these parameters, however, have uncertainties and these uncertainties propagate through the model and lead to parametric uncertainty in the linewidth measurement, along with the scale factor uncertainty and the measurement repeatability. The combined measurement uncertainty is required in order to decide if the result is adequate for its intended purpose and to ascertain if it is consistent with other similar results. The parametric uncertainty for optical photomask measurements derived using an edge threshold approach has been described previously [1]; this paper describes an image library approach to this issue and shows results for optical photomask metrology over a linewidth and spacewidth range of 10 nm to 4 μm. The principles will be described, the 1-dimensional image library used and the method of comparing images, along with a simple interpolation method, will be explained, and results presented. This method is easily extended to any kind of imaging microscope and to p dimensions, where p is the number of imaging parameters used. It is more general than the edge threshold method and leads to markedly different results for features smaller than a wavelength.

Proceedings Article | 17 October 2008 Paper

International photomask linewidth comparison by NIST and PTB

J. Potzick, R. Dixson, R. Quintanilha, M. Stocker, A. Vladar, E. Buhr, W. Häßler-Grohne, B. Bodermann, C. G. Frase, H. Bosse

Proceedings Volume 7122, 71222P (2008) https://doi.org/10.1117/12.801435

KEYWORDS: Photomasks, Metrology, Scanning electron microscopy, Calibration, Microscopes, Chromium, Ultraviolet radiation, Standards development, Critical dimension metrology, Interferometers

Read Abstract +

Proceedings Article | 17 October 2008 Paper

Re-calibration of the NIST SRM 2059 master standard using traceable atomic force microscope metrology

Ronald Dixson, James Potzick, Ndubuisi Orji

Proceedings Volume 7122, 71222Q (2008) https://doi.org/10.1117/12.801923

KEYWORDS: Metrology, Calibration, Photomasks, Standards development, Atomic force microscopy, Atomic force microscope, Ultraviolet radiation, Microscopes, Dimensional metrology, Optical testing

Read Abstract +

Proceedings Article | 30 October 2007 Paper

Photomask applications of traceable atomic force microscope dimensional metrology at NIST

Ronald Dixson, Ndubuisi Orji, James Potzick, Joseph Fu, Richard Allen, Michael Cresswell, Stewart Smith, Anthony Walton, Andreas Tsiamis

Proceedings Volume 6730, 67303D (2007) https://doi.org/10.1117/12.746755

KEYWORDS: Metrology, Calibration, Atomic force microscopy, Photomasks, Standards development, Phase shifts, Dimensional metrology, Atomic force microscope, Resistance, Microelectronics

Read Abstract +

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.

Proceedings Article | 5 April 2007 Paper

Accuracy in optical image modeling

James Potzick, Egon Marx, Mark Davidson

Proceedings Volume 6518, 651814 (2007) https://doi.org/10.1117/12.711499

KEYWORDS: Photomasks, Microscopes, Chromium, Wafer-level optics, Optical imaging, Metrology, Semiconducting wafers, Image processing, Mathematical modeling, Imaging systems

Read Abstract +

Proceedings Article | 20 October 2006 Paper

Parametric uncertainty in optical image modeling

James Potzick, Egon Marx, Mark Davidson

Proceedings Volume 6349, 63494U (2006) https://doi.org/10.1117/12.684670

KEYWORDS: Photomasks, Microscopes, Wafer-level optics, Semiconducting wafers, Objectives, Chromium, Metrology, Optical testing, Image transmission, Quartz

Read Abstract +

Proceedings Article | 5 September 2006 Paper

Optical illumination and critical dimension analysis using the through-focus focus metric method

Ravikiran Attota, Richard Silver, James Potzick

Proceedings Volume 6289, 62890Q (2006) https://doi.org/10.1117/12.681231

KEYWORDS: Critical dimension metrology, Silicon, Optical microscopes, Microscopes, Optical simulations, Overlay metrology, Metrology, Scanning electron microscopy, Cadmium, Image analysis

Read Abstract +

Proceedings Article | 24 May 2004 Paper

Improving the uncertainty of photomask linewidth measurements

J. Pedulla, James Potzick, Richard Silver

Proceedings Volume 5375, (2004) https://doi.org/10.1117/12.539142

KEYWORDS: Photomasks, Calibration, Mathematical modeling, Standards development, Metrology, Light scattering, Process modeling, Optical simulations, Microscopes, Semiconducting wafers

Read Abstract +

The National Institute of Standards and Technology (NIST) is currently developing a photomask linewidth standard (SRM 2059) with a lower expected uncertainty of calibration than the previous NIST standards (SRMs 473, 475, 476). In calibrating these standards, optical simulation modeling has been used to predict the microscope image intensity profiles, which are then compared to the experimental profiles to determine the certified linewidths. Consequently, the total uncertainty in the linewidth calibration is a result of uncertainty components from the optical simulation modeling and uncertainty due to experimental errors or approximations (e.g., tool imaging errors and material characterization errors). Errors of approximation in the simulation model and uncertainty in the parameters used in the model can contribute a large component to the total linewidth uncertainty. We have studied the effects of model parameter variation on measurement uncertainty using several different optical simulation programs that utilize different mathematical techniques. We have also evaluated the effects of chrome edge runout and varying indices of refraction on the linewidth images. There are several experimental parameters that are not ordinarily included in the modeling simulation. For example, the modeling programs assume a uniform illuminating field (e.g., Koehler illumination), ideal optics and perfect optical alignment. In practice, determining whether Koehler illumination has been achieved is difficult, and the optical components and their alignments are never ideal. We will present some techniques for evaluating Koehler illumination and methods to compensate for scattered (flare) light. Any such experimental elements, that are assumed accurate in the modeling, may actually present significant components to the uncertainty and need to be quantitatively estimated. The present state of metrology does not permit the absolute calibration of linewidth standards to the level of uncertainty called for in the semiconductor roadmap. However, there are applications for a linewidth standard and calibration strategies which do not require a NIST certified calibration (e.g., determining measurement precision). In this paper we present various critical elements of a systematic and thorough evaluation of the key components of linewidth uncertainty as well as our methods for evaluating and reducing modeling and experimental uncertainties.

Proceedings Article | 10 July 2003 Paper

Applications of image diagnostics to metrology quality assurance and process control

John Allgair, Victor Boksha, Benjamin Bunday, Alain Diebold, Daniel Cole, Mark Davidson, Jerry Hutcheson, Andrew Gurnell, David Joy, John McIntosh, Sylvain Muckenhirn, Joseph Pellegrini, Robert Larrabee, James Potzick, Andras Vladar, Nigel Smith, Alexander Starikov, Neal Sullivan, Oliver Wells

Proceedings Volume 5042, (2003) https://doi.org/10.1117/12.504320

KEYWORDS: Metrology, Diagnostics, Dimensional metrology, Optical lithography, Manufacturing, Process control, Image processing, Critical dimension metrology, Semiconducting wafers, Edge roughness

Read Abstract +

Proceedings Article | 2 June 2003 Paper

Updated NIST photomask linewidth standard

James Potzick, J. Pedulla, Michael Stocker

Proceedings Volume 5038, (2003) https://doi.org/10.1117/12.487735

KEYWORDS: Calibration, Photomasks, Microscopes, Standards development, Ultraviolet radiation, Interferometers, Error analysis, Metrology, Nano opto mechanical systems, Objectives

Read Abstract +

Proceedings Article | 27 December 2002 Paper

New NIST photomask linewidth standard

James Potzick, J. Marc Pedulla, Michael Stocker

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.467432

KEYWORDS: Calibration, Photomasks, Microscopes, Ultraviolet radiation, Interferometers, Standards development, Metrology, Nano opto mechanical systems, Error analysis, Image processing

Read Abstract +

Proceedings Article | 22 August 2001 Paper

Problem with submicrometer-linewidth standards and a proposed solution

James Potzick

Proceedings Volume 4344, (2001) https://doi.org/10.1117/12.436737

KEYWORDS: Tolerancing, Image transmission, Standards development, Photomasks, Calibration, Metrology, Manufacturing, Semiconducting wafers, Instrument modeling, Refraction

Read Abstract +

Traceable linewidth measurements of tiny features on photomasks and wafers present interesting challenges. Usually technical solutions exist for the problems encountered, but traceability can be costly in time and labor. A measurement is useful only if its value exceeds its cost. One such problem is that an optical or electron microscope forms a scaled image of the linewidth object, which is measured instead of the object itself. Interpreting this image to identify the object's edges in it can be difficult, because the image depends on instrument and object parameters (such as topography and materials) not directly related to the linewidth. Use of a linewidth standard can provide a traceable measurement if the relevant object parameters are known to match those of the standard. In the majority of cases, however, the object being measured and the linewidth standard will differ in topography and/or materials. Then the instrument images of object and standard will also differ, leading to possible measurement errors. Traceability requires that these measurement errors be quantified--a costly prospect. One can calculate the measurement error resulting from object/standard parameter differences. Then a measurement error tolerance can be chosen, and parameter tolerances can be found corresponding to a parametric measurement uncertainty that is consistent with it. These parameter tolerances define islands of tolerance in parameter space over which the parametric uncertainty will be tolerated. The larger the islands, the greater the measurement uncertainty, but the greater the number of different objects whose parameter differences fall on the island. While the calculations for the islands of tolerance may be complex, a single island can apply to a whole group of different objects, reducing the cost of measuring the parameters and calculating their effects. This is a way to obtain traceable linewidth measurements while balancing measurement cost and measurement uncertainty.

Proceedings Article | 22 January 2001 Paper

Neolithography Consortium: a progress report

James Potzick

Proceedings Volume 4186, (2001) https://doi.org/10.1117/12.410747

KEYWORDS: Semiconducting wafers, Photomasks, Optical lithography, Metrology, Virtual reality, Etching, Tolerancing, Device simulation, Process control, Inspection

Read Abstract +

Proceedings Article | 2 June 2000 Paper

The Neolithography Consortium

James Potzick

Proceedings Volume 3998, (2000) https://doi.org/10.1117/12.386503

KEYWORDS: Photomasks, Semiconducting wafers, Optical lithography, Tolerancing, Metrology, Process control, Image processing, Etching, Wafer-level optics, Optical proximity correction

Read Abstract +

Proceedings Article | 18 December 1998 Paper

Accuracy differences among photomask metrology tools and why they matter

James Potzick

Proceedings Volume 3546, (1998) https://doi.org/10.1117/12.332842

KEYWORDS: Metrology, Image resolution, Photomasks, Manufacturing, Standards development, Calibration, Microscopes, Imaging systems, Scanning electron microscopy, Optical microscopes

Read Abstract +

Proceedings Article | 8 June 1998 Paper

Accuracy and traceability in dimensional measurements

James Potzick

Proceedings Volume 3332, (1998) https://doi.org/10.1117/12.308758

KEYWORDS: Calibration, Standards development, Metrology, Photomasks, Scanning electron microscopy, Semiconducting wafers, Manufacturing, Microscopes, Interferometers, Optical microscopes

Read Abstract +

Proceedings Article | 7 July 1997 Paper

Method to characterize overlay tool misalignments and distortions

Richard Silver, James Potzick, Fredric Scire, Christopher Evans, M. McGlauflin, Edward Kornegay, Robert Larrabee

Proceedings Volume 3050, (1997) https://doi.org/10.1117/12.275965

KEYWORDS: Overlay metrology, Error analysis, Motion measurement, Optics manufacturing, Calibration, Diamond turning, Data acquisition, Optical alignment, Confocal microscopy, Photometry

Read Abstract +

Proceedings Article | 12 February 1997 Paper

Photomask metrology in the era of neolithography

James Potzick

Proceedings Volume 3236, (1997) https://doi.org/10.1117/12.284026

KEYWORDS: Photomasks, Semiconducting wafers, Metrology, Phase shifts, Cadmium sulfide, Optical proximity correction, Microscopes, Wafer-level optics, Mask making, Tolerancing

Read Abstract +

Proceedings Article | 13 September 1996 Paper

New certified length scale for microfabrication metrology

James Potzick

Proceedings Volume 2880, (1996) https://doi.org/10.1117/12.250945

KEYWORDS: Calibration, Microscopes, Standards development, Interferometers, Metrology, Scanning electron microscopy, Photomasks, Ultraviolet radiation, Microfabrication, Temperature metrology

Read Abstract +

Proceedings Article | 21 May 1996 Paper

International comparison of photomask linewidth standards: United States (NIST) and United Kingdom (NPL)

James Potzick, John Nunn

Proceedings Volume 2725, (1996) https://doi.org/10.1117/12.240148

KEYWORDS: Photomasks, Calibration, Standards development, Nanolithography, Scanning electron microscopy, Metrology, Electron microscopes, Chromium, Interferometers, Microscopes

Read Abstract +

Proceedings Article | 21 May 1996 Paper

High-accuracy overlay measurements

Richard Silver, James Potzick, Fredric Scire, Robert Larrabee

Proceedings Volume 2725, (1996) https://doi.org/10.1117/12.240093

KEYWORDS: Overlay metrology, Interferometers, Calibration, Metrology, Optical alignment, Mirrors, Motion measurement, Microscopes, Aluminum, Wafer-level optics

Read Abstract +

The reduced critical dimensions of semiconductor devices place more stringent requirements on the uncertainty (including precision and accuracy) of overlay metrology tools used to monitor stepper feature placement. The use of mix and match technologies of phase shift with 1x and 5x stepper techniques and step and scan exposure tools further stresses the need for accuracy in overlay metrology tools. In addition to these pressures it is widely recognized that overlay measurement accuracy can be compromised by misalignments and measurement errors in the optical measurement tool, referred to as a tool-induced-shift. Further errors in the measurement process result from asymmetries of the specimen creating an erroneous overlay shift, referred to as wafer-induced-shift. Our optical overlay metrology program at NIST is currently addressing these measurement concerns with the development of a high-accuracy overlay measurement system. This system will be used for overlay measurement research and the calibration of standard reference artifacts designed to improve standard optical alignment procedures as well as artifacts specifically designed for overlay instrument calibration. We first discuss the design features of our new instrument: the optical measurement system, sample-stage dynamics, the metrology reference frame, and position-measurement systems. We then discuss the fundamental differences between measurement tool errors and wafer- induced errors and the phase-dependent nature of the interactions of the electric fields in the image which result from these errors. Next, difficulties encountered in trying to separate these effects by a simple rotation of the sample followed by analysis of the sum and difference components of the intensity image are investigated. We then briefly describe our design and development approach of two artifacts, one for alignment and scale calibration and the other a conventional box-in-box overlay-specific test structure. This approach is taken to best separate and reduce the error contribution from tool-induced-shift.

Proceedings Article | 3 July 1995 Paper

Improved photomask metrology through exposure emulation

James Potzick

Proceedings Volume 2512, (1995) https://doi.org/10.1117/12.212813

KEYWORDS: Photomasks, Metrology, Semiconducting wafers, Image transmission, Wafer-level optics, Data modeling, Projection systems, Phase shifts, Edge roughness, Photoresist materials

Read Abstract +

Proceedings Article | 22 May 1995 Paper

Re-evaluation of the accuracy of NIST photmask linewidth standards

James Potzick

Proceedings Volume 2439, (1995) https://doi.org/10.1117/12.209206

KEYWORDS: Calibration, Standards development, Photomasks, Microscopes, Image transmission, Scanning electron microscopy, Refraction, Error analysis, Statistical analysis, Geometrical optics

Read Abstract +

Proceedings Article | 22 May 1995 Paper

Overlay measurements and standards

Richard Silver, James Potzick, Robert Larrabee

Proceedings Volume 2439, (1995) https://doi.org/10.1117/12.209209

KEYWORDS: Overlay metrology, Calibration, Microscopes, Standards development, Optical alignment, Photomasks, Metrology, Wafer-level optics, Semiconducting wafers, Ultraviolet radiation

Read Abstract +

Proceedings Article | 22 May 1995 Paper

Metrology with the ultraviolet scanning transmission microscope

Richard Silver, James Potzick, J. Hu

Proceedings Volume 2439, (1995) https://doi.org/10.1117/12.209228

KEYWORDS: Microscopes, Ultraviolet radiation, Interferometers, Photomasks, Calibration, Mirrors, Vibrometry, Metrology, Visible radiation, Photometry

Read Abstract +

Proceedings Article | 7 December 1994 Paper

Improving photomask linewidth measurement accuracy via emulated stepper aerial image measurement

James Potzick

Proceedings Volume 2322, (1994) https://doi.org/10.1117/12.195831

KEYWORDS: Optical testing, Semiconducting wafers, Error analysis, Image transmission, Photomask technology, Photoresist materials, Edge roughness, Calibration, Metrology, Photomasks

Read Abstract +

Proceedings Article | 1 July 1994 Paper

Accuracy in integrated circuit dimensional measurements

James Potzick

Proceedings Volume 10274, 1027409 (1994) https://doi.org/10.1117/12.187463

KEYWORDS: Integrated circuits, Photomasks, Instrument modeling, Measurement devices, Calibration

Read Abstract +

Proceedings Article | 4 August 1993 Paper

Comparisons of measured linewidths of submicrometer lines using optical, electrical, and SEM metrologies

Richard Allen, Patrick Troccolo, James Owen, James Potzick, Loren Linholm

Proceedings Volume 1926, (1993) https://doi.org/10.1117/12.148980

KEYWORDS: Scanning electron microscopy, Metrology, Bridges, Optical testing, Wafer-level optics, Semiconducting wafers, Standards development, Optical microscopy, Resistance, Resistors

Read Abstract +

Proceedings Article | 1 June 1990 Paper

Practical photomask linewidth measurements

James Potzick

Proceedings Volume 1261, (1990) https://doi.org/10.1117/12.20039

KEYWORDS: Photomasks, Calibration, Standards development, Metrology, Reflection, Integrated circuits, Scanning electron microscopy, Inspection, Process control, Optical components

Read Abstract +

Showing 5 of 33 publications

Conference Committee Involvement (4)

Photomask Technology

19 September 2011 | Monterey, California, United States

Photomask Technology

13 September 2010 | Monterey, California, United States

Photomask Technology

15 September 2009 | Monterey, California, United States

Process and Materials Characterization and Diagnostics in IC Manufacturing II

27 February 2003 | Santa Clara, CA, United States

Course Instructor

SC854: Nanoscale Photomask Metrology - Theory and Practice

This course provides attendees with a basic working knowledge of the principles of metrology, with emphasis on measuring the size or placement of features on IC wafers and photomasks. The course covers the metrology concepts defined by ISO (the International Organization for Standardization) and used by national metrology laboratories around the world, and shows how to reduce these concepts to practice in a research or manufacturing environment. Practical examples will be given.

Expand Description +

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years