Dr. William B. Howard Profile

Dr. William B. Howard

Research Scientist at KLA Texas

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Publications (16)

Proceedings Article | 3 May 2007 Paper

Production evaluation of automated reticle defect printability prediction application

William Howard, Scott Pomeroy, Raphael Moses, Thomas Thaler

Proceedings Volume 6533, 65330A (2007) https://doi.org/10.1117/12.736495

KEYWORDS: Reticles, Inspection, Photomasks, Lithography, Critical dimension metrology, Manufacturing, Systems modeling, Semiconducting wafers, Binary data, Metrology

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Proceedings Article | 27 March 2007 Paper

Modeling and performance metrics for longitudinal chromatic aberrations, focus-drilling, and Z-noise: exploring excimer laser pulse-spectra

Mark Smith, Joseph Bendik, Ivan Lalovic, Nigel Farrar, William Howard, Chris Sallee

Proceedings Volume 6520, 65203E (2007) https://doi.org/10.1117/12.714102

KEYWORDS: Lithography, Excimers, Chromatic aberrations, Excimer lasers, Optical simulations, Data modeling, 193nm lithography, Photomasks, Electroluminescence, Performance modeling

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Proceedings Article | 16 June 2005 Paper

Accurate aerial image simulation using high-resolution reticle inspection images

William Howard, Chris Mack

Proceedings Volume 5835, (2005) https://doi.org/10.1117/12.637289

KEYWORDS: Reticles, Inspection, Metrology, Lithography, Computer simulations, Semiconducting wafers, Photomasks, Manufacturing, Calibration, Solids

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Proceedings Article | 5 May 2005 Paper

Inspection of integrated circuit databases through reticle and wafer simulation: an integrated approach to design for manufacturing (DFM)

William Howard, Jaione Tirapu Azpiroz, Yalin Xiong, Chris Mack, Gaurav Verma, William Volk, Harold Lehon, Yunfei Deng, Rui-fang Shi, James Culp, Scott Mansfield

Proceedings Volume 5756, (2005) https://doi.org/10.1117/12.604698

KEYWORDS: Inspection, Semiconducting wafers, Reticles, Design for manufacturing, Scanning electron microscopy, Optical proximity correction, Lithography, Resolution enhancement technologies, Calibration, Defect detection

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Proceedings Article | 17 December 2003 Paper

A study of defect measurement techniques and corresponding effects on the lithographic process window for a 193-nm EPSM photomask

Anthony Nhiev, Jason Hickethier, Haiqing Zhou, Trent Hutchinson, William Howard, Mohsen Ahmadian

Proceedings Volume 5256, (2003) https://doi.org/10.1117/12.518048

KEYWORDS: Inspection, Scanning electron microscopy, Photomasks, Semiconducting wafers, Deep ultraviolet, Reticles, Lithography, Opacity, Critical dimension metrology, Printing

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Proceedings Article | 26 June 2003 Paper

Application-specific methods for creating simulation masks

William Howard, Darren Taylor

Proceedings Volume 5040, (2003) https://doi.org/10.1117/12.485536

KEYWORDS: Photomasks, Reticles, Lithography, Semiconducting wafers, Image processing, Monte Carlo methods, Diffraction, Manufacturing, Objectives, Transmittance

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Proceedings Article | 27 December 2002 Paper

PRIMADONNA: a system for automated defect disposition of production masks using wafer lithography simulation

Daniel Bald, Saghir Munir, Barry Lieberman, William Howard, Chris Mack

Proceedings Volume 4889, (2002) https://doi.org/10.1117/12.467768

KEYWORDS: Inspection, Photomasks, Semiconducting wafers, Lithography, Image processing, Reticles, Databases, Defect inspection, Infrared imaging, Computer simulations

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Proceedings Article | 16 August 2002 Paper

OPC aware mask and wafer metrology

Wilhelm Maurer, Vincent Wiaux, Rik Jonckheere, Vicky Philipsen, Thomas Hoffmann, Staf Verhaegen, Kurt Ronse, Jonathan England, William Howard

Proceedings Volume 4764, (2002) https://doi.org/10.1117/12.479350

KEYWORDS: Optical proximity correction, Photomasks, Lithography, Metrology, Image processing, Scanning electron microscopy, Semiconducting wafers, Image analysis, Transistors, Line edge roughness

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Proceedings Article | 30 July 2002 Paper

Tuning and simulating a 193-nm resist for 2D applications

William Howard, Vincent Wiaux, Monique Ercken, Bang Bui, Jeff Byers, Mike Pochkowski

Proceedings Volume 4691, (2002) https://doi.org/10.1117/12.474499

KEYWORDS: Photomasks, Semiconducting wafers, Scanning electron microscopy, Optical proximity correction, Metrology, Reticles, Finite element methods, Data modeling, Lithography, 3D image processing

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Proceedings Article | 30 July 2002 Paper

Assessment of OPC effectiveness using two-dimensional metrics

Vincent Wiaux, Vicky Philipsen, Rik Jonckheere, Geert Vandenberghe, Staf Verhaegen, Thomas Hoffmann, Kurt Ronse, William Howard, Wilhelm Maurer, Moshe Preil

Proceedings Volume 4691, (2002) https://doi.org/10.1117/12.474588

KEYWORDS: Reticles, Optical proximity correction, Photomasks, Scanning electron microscopy, Semiconducting wafers, Critical dimension metrology, Optical lithography, Metrology, Printing, Logic

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A complete evaluation of the optical proximity effects (OPE) and of their corrections (OPC) requires a quantitative description of two-dimensional (2D) parameters, both at resist- and at reticle-level. Because the 2D behaviour at line-ends and at line-corners can become a limiting factor for the yield, it should be taken into account when characterising a process, just as the CD- and pitch-linearity are already kept under control. This implies the measurement of 2D-metrics in a precise way. We used an SEM Image Analysis tool (ProDATA SIAM) to define and measure various OPC-relevant metrics for a C013 process. For the METAL (M1) process, we show that the overlap between line-ends of M1-trenches and underlying nominal contacts is a relevant metric to describe the effectiveness of hammerheads. Moreover, it is an interesting metric to combine with the CD process window. For the GATE process, we demonstrate that for a given set of metrics there is a degree of OPC aggressiveness beyond which it is not worth to go. We considered both line-end shortening (LES) and corner rounding affecting the poly linewidth close to a contact pad, and this on various logic circuits having received different degrees of fragmentation. Finally the knowledge of the actual line-end contour on the reticle allows one to simulate separately the printing effect of that area loss at reticle line-ends. The area loss measured by comparing the extracted contour to the target one is regarded as a combination of pull-back and area loss at corners. For our C013 gate process, and for the 130nm lines at a 1:1.25 duty cycle, those two parameters contribute together to approximetely 40% of the measured LES in the resist. This fact raises the question of specifications on 2D reticle parameters. We also find a linear correlation between the area loss at reticle line-end corners and the corresponding increase of LES on the wafer, which suggests a way towards putting specifications on the reticle line-ends.

Proceedings Article | 11 March 2002 Paper

Improved method for measuring and assessing reticle pinhole defects

Darren Taylor, Anthony Vacca, Larry Zurbrick, William Howard, William Broadbent

Proceedings Volume 4562, (2002) https://doi.org/10.1117/12.458300

KEYWORDS: Reticles, Scanning electron microscopy, Inspection, Semiconducting wafers, Manufacturing, Metrology, Lithography, Scanners, Photomasks, Wafer inspection

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Proceedings Article | 19 July 2000 Paper

Improving reticle quality through reticle blank inspection

William Howard, Kevin Krause

Proceedings Volume 4066, (2000) https://doi.org/10.1117/12.392041

KEYWORDS: Inspection, Reticles, Contamination, Optical inspection, Calibration, Critical dimension metrology, Cadmium, Nondestructive evaluation, Modulation, Visualization

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Proceedings Article | 3 February 2000 Paper

Implementing reticle blank inspection in a production environment

Kevin Krause, William Howard

Proceedings Volume 3996, (2000) https://doi.org/10.1117/12.377116

KEYWORDS: Inspection, Reticles, Contamination, Bridges, Standards development, Modulation, Visualization, Electron beams, Software development, Integrated circuits

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Proceedings Article | 3 February 2000 Paper

Advanced CD error detection with CD SEM disposition

Darren Taylor, Barry Rockwell, Aihua Dong, Anthony Vacca, Waiman Ng, Geoffrey Anderson, William Howard

Proceedings Volume 3996, (2000) https://doi.org/10.1117/12.377115

KEYWORDS: Reticles, Inspection, Critical dimension metrology, Scanning electron microscopy, Semiconducting wafers, Photomasks, Optical metrology, Electrons, Ultraviolet radiation, Calibration

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Proceedings Article | 30 December 1999 Paper

Techniques to inspect SCALPEL masks

Darren Taylor, William Howard, Richard Kasica, Reginald Farrow, Anthony Novembre, Carlos Caminos, Chester Knurek

Proceedings Volume 3873, (1999) https://doi.org/10.1117/12.373300

KEYWORDS: Charged-particle lithography, Photomasks, Inspection, Lithography, Semiconducting wafers, Calibration, Silicon, Electron beams, Prototyping, Reticles

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Proceedings Article | 30 December 1999 Paper

Reticle blank inspection and its role in zero-defect manufacturing

Kevin Krause, William Howard

Proceedings Volume 3873, (1999) https://doi.org/10.1117/12.373363

KEYWORDS: Reticles, Inspection, Contamination, Bridges, Manufacturing, Modulation, Autoregressive models, Detection and tracking algorithms, Calibration, Defect inspection

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Showing 5 of 16 publications

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