High Aspect Ratio Parylene Etching for Microfluidics and Biomems

A novel technique for producing high aspect ratio parylene structures via switching chemistry plasma etching is presented. Parylene C, or poly(monochloro-p-xylylene), has become an increasingly popular MEMS material for its excellent properties and biocompatibility. However, the inability to fabricate closely-spaced high aspect ratio (HAR) structures severely limits the use of parylene, particularly in microfluidic and bioMEMS applications. A novel method was developed to etch thin film parylene deposited on silicon substrates. Several masking materials were investigated to optimize this process. This low-temperature (<120 °C) technique is compatible with standard MEMS processes and can accommodate post-CMOS processing. Etching recipes have already been applied to bioMEMS devices and can greatly extend the range of possible structures for bioMEMS and microfluidics applications.