Dr. Charles D. Schaper Profile

Dr. Charles D. Schaper

President/CEO at Transfer Devices Inc

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Author

Publications (11)

Proceedings Article | 3 April 2010 Paper

Automating molecular transfer lithography at 25nm on 200mm wafers including site-remote coating of resist on dissolvable templates

Charles Schaper

Proceedings Volume 7637, 76370U (2010) https://doi.org/10.1117/12.848402

KEYWORDS: Lithography, Semiconducting wafers, Coating, Optical lithography, Silicon, Photoresist processing, Nanostructures, Manufacturing, Optical alignment, Polymers

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Proceedings Article | 20 May 2004 Paper

Nanofabrication with water-dissolvable polymer masks of polyvinyl alcohol (PVA): MxL

Charles Schaper

Proceedings Volume 5374, (2004) https://doi.org/10.1117/12.534928

KEYWORDS: Polymers, Adhesives, Thin films, Photomasks, Printing, Silicon, Solids, Particles, Polymer thin films, Lithography

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SPIE Journal Paper | 1 January 2004

Water-soluble polymer templates for high-resolution pattern formation and materials transfer printing

Charles Schaper

JM3, Vol. 3, Issue 01, (January 2004) https://doi.org/10.1117/12.10.1117/1.1630805

KEYWORDS: Polymers, Adhesives, Lithography, Liquids, Printing, Solids, Semiconducting wafers, Optical alignment, Polymer thin films, Silicon

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Proceedings Article | 16 June 2003 Paper

MxL: pseudo-maskless high-throughput nanolithography

Charles Schaper

Proceedings Volume 5037, (2003) https://doi.org/10.1117/12.484420

KEYWORDS: Semiconducting wafers, Printing, Lithography, Polymers, Liquids, Adhesives, Silicon, Etching, Solids, Optical alignment

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Proceedings Article | 23 August 2000 Paper

Real-time control of photoresist thickness uniformity during the bake process

Lay Lay Lee-Aquila, Charles Schaper, Weng Khuen Ho

Proceedings Volume 4182, (2000) https://doi.org/10.1117/12.410103

KEYWORDS: Photoresist processing, Process control, Reflectivity, Process modeling, Semiconducting wafers, Error analysis, Lithography, Sensors, Coating, Critical dimension metrology

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Proceedings Article | 3 September 1999 Paper

Spatially programmable temperature control and measurement for chemically amplified photoresist processing

Charles Schaper, Khalid El-Awady, Arthur Tay

Proceedings Volume 3882, (1999) https://doi.org/10.1117/12.361326

KEYWORDS: Temperature metrology, Semiconducting wafers, Photomasks, Photoresist materials, Chemical elements, Photoresist processing, Control systems, Feedback control, Process control, Silicon

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Proceedings Article | 3 September 1999 Paper

Optimal control strategy using linear programming for load disturbance compensation in thermal processing systems

Weng Khuen Ho, Arthur Tay, Charles Schaper

Proceedings Volume 3882, (1999) https://doi.org/10.1117/12.361294

KEYWORDS: Semiconducting wafers, Temperature metrology, Data modeling, Control systems, Computer programming, Feedback control, Photomasks, Photoresist processing, Temperature sensors, Thermal modeling

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SPIE Journal Paper | 1 April 1993

Machine vision techniques for subpixel estimation of critical dimensions

Hamid Aghajan, Charles Schaper, Thomas Kailath

OE, Vol. 32, Issue 04, (April 1993) https://doi.org/10.1117/12.10.1117/12.132375

KEYWORDS: Neural networks, Edge detection, Hough transforms, Semiconducting wafers, Scanning electron microscopy, Machine vision, Image classification, Machine learning, Edge roughness, Microscopes

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Proceedings Article | 1 June 1992 Paper

Pattern recognition algorithms for linewidth measurement

Hamid Aghajan, Charles Schaper, Thomas Kailath

Proceedings Volume 1673, (1992) https://doi.org/10.1117/12.59786

KEYWORDS: Neural networks, Edge detection, Integrated circuits, Hough transforms, Metrology, Inspection, Sensors, Scanning electron microscopy, Process control, Semiconducting wafers

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Novel edge detection and line fitting pattern recognition algorithms are applied for linewidth measurement on images of integrated circuits. The strategy employs a two step procedure. In the first step, a neural network is used for edge detection of the image. Three neural network approaches are investigated: bootstrap linear threshold, self-organizing, and constrained maximization strategies. These neural networks combine filtering and thresholding to reduce noise and aberrations in the image. Further, the parameters of the neural network are estimated using an unsupervised learning procedure. The advantage of this learning strategy is the ability to adapt to the imaging environment. Consequently, these proposed neural network approaches for edge detection do not require an a priori database of images with known linewidths for calibration. In the second step, new line-fitting methods are applied to the edge maps defined by the neural network to compute linewidth. Two methods are investigated: an eigenvector strategy and a technique that is based on a reformulation of the line-fitting problem such that advanced signal processing techniques can be employed. The latter algorithm is capable of fitting multiple lines in an image which need not be parallel and possesses computational speed superiority over conventional techniques and can be implemented on-line. By employing this two-step strategy, the entire image is used to estimate linewidth as opposed to a single or few line scans. Thus, edge roughness effects can be spatially averaged to obtain an optimal estimate of linewidth. The techniques are general and can be used on images form a variety of microscopes including optical and electron-beam. The pattern recognition algorithms are applied to images of patterned wafers with lines smaller than 1 micrometers wide. These images are obtained by optical microscopes. The estimated linewidths are shown to be in close agreement with those measured by scanning electron microscopes. The application of the proposed pattern recognition techniques to solve other problems in IC metrology, such as rotational wafer alignment, is also discussed.

Proceedings Article | 1 June 1992 Paper

Computer-aided optimal design of phase-shifting masks

Chih-Yuan Chang, Charles Schaper, Thomas Kailath

Proceedings Volume 1674, (1992) https://doi.org/10.1117/12.130310

KEYWORDS: Phase shifts, Photomasks, Optical lithography, Computer aided design, Imaging systems, Integrated circuits, Image transmission, Diffraction, Optical resolution, Manufacturing

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Proceedings Article | 1 February 1992 Paper

Modeling and control of rapid thermal processing

Charles Schaper, Young Cho, Poogyeon Park, Stephen Norman, Paul Gyugyi, G. Hoffmann, S. Balemi, Stephen Boyd, Gregory Franklin, Thomas Kailath, Krishna Saraswat

Proceedings Volume 1595, (1992) https://doi.org/10.1117/12.56658

KEYWORDS: Semiconducting wafers, Lamps, Temperature metrology, Sensors, Systems modeling, Thermal modeling, Data modeling, Control systems, Feedback control, Signal processing

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Showing 5 of 11 publications

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