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Proceedings Paper

Image optimization for maskless lithography
Author(s): Yashesh A. Shroff; Yijian Chen; William G. Oldham
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Paper Abstract

This paper discusses image optimization challenges posed by a mirror based pattern generation scheme. We address defocus related image drift encountered with mirror based maskless lithography. While off-grid contacts printed with piston mirrors are most severely affected most other features can be printed with minimum loss of telecentricity. A novel double-piston mirror architecture based on a combination of tilting and piston mirrors is introduced. It operates as a pseudo-tilt mirror but also has the advantage of allowing strong phase-edges due to pure-phase wavefront modulation. Exposure latitude versus depth-of-focus process window curves of typical features show that the new mirror design behaves as well as tilting mirror. An image optimization algorithm is presented that iteratively updates the mirror array phase-map to optimally print dense layout, accounting for inter and intra feature proximity effects.

Paper Details

Date Published: 20 May 2004
PDF: 11 pages
Proc. SPIE 5374, Emerging Lithographic Technologies VIII, (20 May 2004); doi: 10.1117/12.548797
Show Author Affiliations
Yashesh A. Shroff, Univ. of California/Berkeley (United States)
Yijian Chen, Univ. of California/Berkeley (United States)
William G. Oldham, Univ. of California/Berkeley (United States)

Published in SPIE Proceedings Vol. 5374:
Emerging Lithographic Technologies VIII
R. Scott Mackay, Editor(s)

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