Title :
Top-edge profile control for SU-8 structural photoresist
Author :
Lee, S.J. ; Shi, W. ; Maciel, P. ; Cha, S.W.
Author_Institution :
San Jose State Univ., CA, USA
fDate :
30 June-2 July 2003
Abstract :
Profile control for SU-8 ultrathick photoresist has been examined specifically with respect to a "T-topping" phenomenon observed at the top edge. It has been confirmed that filtering ultraviolet (UV) radiation below 350 nm is successful in correcting this type of geometric defect. The effectiveness of a doped glass filter (Hoya UV-34) has been verified, and an alternative approach using a vapor-deposited thin-film coating has been presented. The thin-film filter demonstrates equal success in reducing the T-topping defect. This alternative approach furthermore offers advantages related to cost, design flexibility, robustness, and environmental impact. Modifying exposure dose and pre-bake temperature without any filter was observed to have minimal impact.
Keywords :
geometrical optics; optical filters; optical glass; photoresists; ultraviolet spectra; vapour deposited coatings; 350 nm; Hoya UV-34; T-topping; cost; design flexibility; doped glass filter; environmental impact; geometric defect; minimal impact; pre-bake temperature; robustness; thin-film filter; top-edge profile control; ultrathick photoresist; ultraviolet radiation filtering; vapor-deposited thin-film coating; Coatings; Dielectric thin films; Filtering; Filters; Glass; Optical refraction; Resists; Substrates; Temperature; Transistors;
Conference_Titel :
University/Government/Industry Microelectronics Symposium, 2003. Proceedings of the 15th Biennial
Print_ISBN :
0-7803-7972-1
DOI :
10.1109/UGIM.2003.1225777
