Fabrication of implantable microshunt using a novel channel sealing technique

Abstract

This letter reports the development of a novel microshunt by combining biocompatible materials with well-established, robust microelectromechanical systems (MEMS) fabrication processes. The key features of our microshunt fabrication process are summarized as follows: (1) Control over the thickness of channels' enclosure, (2) channels' height scalable by multiple thick resist patterning, (3) structural material deposition by electroplating, and (4) an easy fabrication process suitable for mass production. These features were realized using electroplating for the gold structural material, photoresist sacrificial material, and e-beam evaporation of adhesion layers. The combination of these techniques allows precise control on the microchannels width, depth, and length. A novel channel sealing technique that is extendable to more complex geometries is also presented. The developed method involves using a thin gold seed layer deposited via evaporation prior to electroplating the last structural layer, the cover of the channels. This method enhanced the electroplating process, yielding more control of the final thickness of the cover layer compared to methods consisting of overgrowing the channels until they seal. (C) 2008 Society of Photo-Optical Instrumentation Engineers. [DOI:10.1117/1.2955935]