Dr. S. Wilson Profile

Dr. S. Wilson

Applications Engg Manager

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Publications (9)

Proceedings Article | 8 December 1995 Paper

24"x 20" precision photomasks manufacture

Graciela Guel, Martin Boothman, Daniel Rector, Susan Wilson

Proceedings Volume 2621, (1995) https://doi.org/10.1117/12.228177

KEYWORDS: Photomasks, Inspection, Manufacturing, Lithography, Glasses, Metrology, Printing, Reticles, Quartz, Light scattering

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Proceedings Article | 22 May 1995 Paper

Metrology of etched quartz and chrome embedded phase shift gratings using scatterometry

Susan Wilson, S. Sohail Naqvi, John McNeil, Herschel Marchman, Blaine Johs, Roger French, Franklin Kalk

Proceedings Volume 2439, (1995) https://doi.org/10.1117/12.209233

KEYWORDS: Photomasks, Quartz, Etching, Diffraction gratings, Phase shifts, Oxides, Scatterometry, Atomic force microscopy, Diffraction, Scatter measurement

Proceedings Article | 7 December 1994 Paper

Phase-shift mask metrology using scatterometry

Susan Wilson, Herschel Marchman, S. Sohail Naqvi, John McNeil

Proceedings Volume 2322, (1994) https://doi.org/10.1117/12.195826

KEYWORDS: Etching, Diffraction gratings, Quartz, Photomasks, Scatterometry, Atomic force microscopy, Scatter measurement, Diffraction, Phase shifts, Metrology

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Proceedings Article | 26 March 1993 Paper

Application of laser scatterometry to characterize phase-shifting masks

Susan Wilson, Gary Peterson, S. Sohail Naqvi, John McNeil

Proceedings Volume 1809, (1993) https://doi.org/10.1117/12.142147

KEYWORDS: Etching, Photomasks, Ion beams, Quartz, Scatterometry, Sensors, Phase shifts, Surface roughness, Phase shifting, Light scattering

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Proceedings Article | 1 August 1992 Paper

Wafer examination and critical dimension estimation using scattered light

Richard Krukar, Susan Gaspar, Scott Wilson, Donald Hush, S. Sohail Naqvi, John McNeil

Proceedings Volume 1661, (1992) https://doi.org/10.1117/12.130298

KEYWORDS: Semiconducting wafers, Diffraction gratings, Light scattering, Diffraction, Fourier transforms, Edge roughness, Neural networks, Statistical analysis, Line edge roughness, Cameras

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Proceedings Article | 1 June 1992 Paper

Latent image exposure monitor using scatterometry

Lisa-Michelle Milner, Kirt Hickman, Susan Wilson, Kenneth Bishop, S. Sohail Naqvi, John McNeil, Matthew Blain, B. Draper

Proceedings Volume 1673, (1992) https://doi.org/10.1117/12.59798

KEYWORDS: Semiconducting wafers, Photoresist materials, Diffraction gratings, Critical dimension metrology, Picture Archiving and Communication System, Light scattering, Cadmium, Process control, Diffraction, Metals

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Proceedings Article | 1 October 1991 Paper

Grating line shape characterization using scatterometry

Kenneth Bishop, Susan Gaspar, Lisa-Michelle Milner, S. Sohail Naqvi, John McNeil

Proceedings Volume 1545, (1991) https://doi.org/10.1117/12.49402

KEYWORDS: Diffraction gratings, Photoresist materials, Diffraction, Scatterometry, Scatter measurement, Silica, Dielectrics, Inverse problems, Silicon, Scanning electron microscopy

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Proceedings Article | 1 July 1991 Paper

Use of diffracted light from latent images to improve lithography control

Kirt Hickman, Susan Gaspar, Kenneth Bishop, S. Sohail Naqvi, John McNeil, Gary Tipton, Brian Stallard, B. Draper

Proceedings Volume 1464, (1991) https://doi.org/10.1117/12.44439

KEYWORDS: Photoresist materials, Semiconducting wafers, Optical properties, Critical dimension metrology, Process control, Lithography, Diffraction, Cadmium, Integrated circuits, Diffraction gratings

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As the microelectronics industry strives to achieve smaller device design geometries, control of linewidth, or critical dimension (CD), becomes increasingly important. Currently, CD uniformity is controlled by exposing large numbers of samples for a fixed exposure time which is determined in advance by calibration techniques. This type of control does not accommodate variations in optical properties of the wafers that may occur during manufacturing. In this work, a relationship is demonstrated between the intensity of light diffracted from a latent image consisting of a periodic pattern in the undeveloped photoresist and the amount of energy absorbed by the resist material (the exposure dose). This relationship is used to simulate exposure dose control of photoresist on surfaces which have different optical properties chosen to represent surfaces typical of those found in operating process lines. Samples include a variety of photoresist materials and substrates with a wide variety of optical properties. The optical properties of the substrates were deliberately varied to determine the effect of these properties on CD (in the presence and absence of an exposure monitor) during lithography. It was observed that linewidth uniformity of the developed photoresist can be greatly improved when the intensity of diffracted light from the latent image is used to control the exposure dose. Diffraction from the latent image grating structures was modeled using rigorous coupled wave analysis. The modeling is used to predict the diffraction from a latent image as a function of the substrate optical properties and the parameters of the latent image (i.e., linewidth, sidewall angle). Good agreement is obtained between theoretical and experimental observations. Conversely, the inverse problem is solved in which the parameters of the diffracting structure (the latent image) are determined from a measurement of the diffracted power. Therefore, the diffracted power can be monitored for the purpose of determining when the latent image will produce the proper CD upon development.

Proceedings Article | 1 June 1990 Paper

Simple technique for linewidth measurement of gratings on photomasks

S. Sohail Naqvi, Susan Wilson, Kirt Hickman, John McNeil

Proceedings Volume 1261, (1990) https://doi.org/10.1117/12.20079

KEYWORDS: Photomasks, Glasses, Scatter measurement, Diffraction gratings, Critical dimension metrology, Integrated circuits, Inspection, Process control, Metrology, Laser scattering

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Showing 5 of 9 publications

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