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Proceedings Paper

Application of liquid crystal polymer films for photolithographic fabrication of 3D structures
Author(s): Anna E. Fox; Adam K. Fontecchio
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Paper Abstract

In this paper, we demonstrate a silicon etching application of a holographically formed polymer dispersed liquid crystal (H-PDLC) photomask. H-PDLC is a periodically nanostructured material consisting of stratified layers of polymer and liquid crystal. Due to the natural random alignment of the liquid crystal axes with respect to the polymer layers, an index of refraction mismatch exists and a reflection occurs. Application of bias across the film aligns the liquid crystals and eliminates the index mismatch causing the film to become transparent. H-PDLC films have been shown to sufficiently attenuate the UV exposure dose in the photolithographic process when in the unbiased state, and can be electrically controlled to modulate the amount of UV transmission when electric field is applied. We show etch depth profiles of patterns masked on a silicon substrate using the H-PDLC photomask device compared with etch profiles of similar structures patterned with more conventional ink jet printed photomasks and chrome on quartz glass photomasks. We investigate reactive ion etching technique and potassium hydroxide wet etch technique.

Paper Details

Date Published: 22 February 2008
PDF: 8 pages
Proc. SPIE 6912, Practical Holography XXII: Materials and Applications, 691202 (22 February 2008); doi: 10.1117/12.760715
Show Author Affiliations
Anna E. Fox, Drexel Univ. (United States)
Adam K. Fontecchio, Drexel Univ. (United States)

Published in SPIE Proceedings Vol. 6912:
Practical Holography XXII: Materials and Applications
Hans I. Bjelkhagen; Raymond K. Kostuk, Editor(s)

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