Reinforced silicon neural microelectrode array fabricated using a commercial MEMS process

Abstract

We report the development of a silicon microelectrode array for brain machine interfaces and neural prosthesis fabricated in a commercial microelectromechanical systems (MEMS) process. We demonstrate high-aspect ratio silicon microelectrodes that reach 6.5 mm in length while having only 10 µm thickness. The fabrication of such elongated neural microelectrodes could lead to the development of cognitive neural prosthetics. Cognitive neural signals are higher level signals that contain information related to the goal of movements such as reaching and grasping and can be recorded from deeper regions of the brain such as the parietal reach region (PRR). We propose a new concept of reinforcing the regions of the electrodes that are more susceptible to breakage to withstand the insertion axial forces, retraction forces, and tension forces of the brain tissue during surgical implantation. We describe the design techniques, detailed analytical models, and simulations to develop reinforced silicon-based elongated neural electrodes. The electrodes are fabricated using the commercial MicraGem process from Micralyne, Inc. The use of a commercial MEMS fabrication process for silicon neural microelectrodes development yields low-cost, mass-producible, and well-defined electrode structures.