Paper
1 April 2008 A photolithographic process for grossly non-planar substrates
Gavin L. Williams, Richard P. McWilliam, Jesus Toriz-Garcia, Richard Curry, Andrew Maiden, N. Luke Seed, Alan Purvis, Peter A. Ivey
Author Affiliations +
Abstract
We describe a technique whereby photolithography has been extended to the patterning of near micron-scale features onto grossly non-planar substrates. Examples will be given of track widths down to ten microns patterned over surfaces with vertical dimensions in excess of one centimetre - far outside the normal bounds of photolithography. The technique enables many novel microsystem packaging schemes and provides an alternative to the direct-write methods that are traditionally employed for patterning non-planar surfaces. The technique is based on the computation of the phase/amplitude distribution on the mask that, when illuminated with light of sufficient spatial coherence, will recreate the desired non-planar light distribution. This has some similarities to existing RET and inverse lithography techniques, but is extended to grossly non-planar surfaces. Exposure of an electrophoretic photoresist-coated substrate to the light field created by the mask enables the non-planar pattern to be transferred to the substrate. The holographic mask contains localized Fresnel patterns. We discuss the analytical methods used for their computation, the approximations necessary to enable mask manufacture and the effects of these approximations on image quality. We also discuss more general numerical methods of mask computation.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Gavin L. Williams, Richard P. McWilliam, Jesus Toriz-Garcia, Richard Curry, Andrew Maiden, N. Luke Seed, Alan Purvis, and Peter A. Ivey "A photolithographic process for grossly non-planar substrates", Proc. SPIE 6921, Emerging Lithographic Technologies XII, 69212E (1 April 2008); https://doi.org/10.1117/12.769148
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CITATIONS
Cited by 3 scholarly publications and 2 patents.
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KEYWORDS
Photomasks

Computer generated holography

Optical lithography

Binary data

Holography

Photoresist materials

Manufacturing

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