Parylene encapsulated sub-micron structures for implantable BiOMEMS

Abstract

We present a method for sub-micron machining of flexible, thin-film structures fully encapsulated in biocompatible polymer poly(chloro-p-xylylene) (Parylene C) that improves feature size and resolution by an order of magnitude compared to prior work. A low temperature electron beam lithography (EBL) process compatible with Parylene-coated silicon substrates was developed, and characterized using patterned Ti structures with critical dimensions down to 250 nm, including conducting traces, serpentine resistors, and electrodes with a nano-patterned texture. Using this newly developed technique, the first flexible, free-film Parylene-Ti-Parylene devices with nanoscale components were fabricated and characterized. One application of these sub-micron structures encapsulated in Parylene is next generation minimally invasive implants. Thus, we also demonstrated a prototype high density Parylene-based microelectrode neural probe using our nanopatterning approach.