A High-Yield Fabrication Process for Silicon Neural Probes

Abstract

There is a great need for silicon microelectrodes that can simultaneously monitor the activity of many neurons in the brain. However, one of the existing processes for fabricating silicon microelectrodes—reactive- ion etching in combination with anisotropic KOH etching—breaks down at the wet-etching step for device release. Here we describe amodified wet-etching sidewall-protection technique for the high-yield fabrication of well-defined silicon probe structures, using a Teflon® shield and low-pressure chemical vapor deposition (LPCVD) silicon nitride. In the proposed method, a micro-tab holds each individual probe to the central scaffold, allowing uniform anisotropicKOHetching. Using this approach, we obtained a well-defined probe structure without device loss during the wet-etching process. This simple method yielded more accurate fabrication and an improved mechanical profile.