The thick photoresist SU8, by virtue of its good mechanical durability, water impermeability and dielectric properties on polymerisation, is widely used as a resin for making high aspect ratio, functional MEMS device structures and packaging parts. However, the difficulty associated with removal, stripping or repatterning of the polymerised SU8 remains a serious issue. This paper presents a novel process, based on O2/SF6 plasma etching, for patterning or removal of fully cross-linked SU8. The Taguchi methodology is used to optimise the O2/SF6 mix for a high etch rate and low under cut.
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Design, Test, Integration and Packaging of MEMS/MOEMS 2003. Symposium on
Date of Conference: 5-7 May 2003