Paper
20 May 2004 Image optimization for maskless lithography
Yashesh A. Shroff, Yijian Chen, William G. Oldham
Author Affiliations +
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.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yashesh A. Shroff, Yijian Chen, and William G. Oldham "Image optimization for maskless lithography", Proc. SPIE 5374, Emerging Lithographic Technologies VIII, (20 May 2004); https://doi.org/10.1117/12.548797
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CITATIONS
Cited by 9 scholarly publications and 2 patents.
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KEYWORDS
Mirrors

Modulation

Photomasks

Phase shift keying

Image processing

Maskless lithography

Micromirrors

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