Fabrication of flexible 3D microelectrode aray with parylene-based pattern transfer technique

This paper describes a new three-dimension (3D) flexible parylene-based microelectrode array (MEA) developed for functional electrical stimulation in neural prosthesis. These arrays with 3D tip profile and gold surface were microfabricated employing a parylene-based pattern transfer technique. Silicon tip array was etched by the HNA etchant and covered with parylene hereafter. Metallization on this parylene structure was achieved by an aluminum-photoresist dual-layer lift-off process. Finally, this parylene-metal thin film was peeled off from the substrate. Electrical characteristic of this 3D electrode was numerically studied and compared with that of a conventional planar microelectrode. Electric field focusing of 3D electrode revealed its priority to the planar one. With easy fabrication process and excellent electrical performance, the present 3D microelectrode array will be a promising candidate for high-density stimulation applications.