Processing of platinum electrodes for parylene-C based neural probes

Abstract

This paper reports a method to improve the electrochemical properties of platinum electrodes fabricated using parylene-C based processes. It is found that the use of O2 reactive-ion etch to etch parylene-C, the state-of-the-art method for processing parylene-C, oxidizes a surface layer of platinum, which results in high electrochemical impedance of the electrode. By introducing an Ar+ ion milling step, the electrochemical impedance of the electrode is reduced by an order of magnitude. The surface roughness of the electrodes (Ra) using this method of de-insulation is found to be 13.1 nm.