Microfabrication of High-Density Microelectrode Arrays for Peripheral Intraneural Applications

This paper presents a novel approach to fabricate a high-density silicon microelectrode array on a silicon-glass bonded substrate. Electrodes were created with deep-reactive-ion etching (DRIE), and sharpened with a mixture of hydrofluoric, nitric, and acetic acids (HNA) wet etchant. A partial photoresist exposure method was developed to encapsulate the electrodes. A 10 times 10 microelectrode array was demonstrated in a 1 mm² area. In addition, a novel fabrication technique was incorporated to create the microelectrodes each with a different length to allow better access to the entire cross section of the target nerve bundle. Both the preliminary mechanical and electrical characteristics of the prototype devices were promising for use as peripheral intraneural probes.