Sandwich electrode technology for precise vestibular electrodes with high reliability

Development of multi-channel microelectrodes for interfacing the vestibular system makes high demands on fabrication technology. To be able to insert such electrodes in the semicircular canals, adequate stiffness of the structures is required. Moreover, a double-sided arrangement of the electrode contacts is desired, in order to increase selectivity. In this work, two approaches are presented and compared to create such electrode systems. While using a double-sided photolithography process is a suitable method to create very thin and flexible monolithic double-sided electrode structures, application in a vestibular prosthesis demands fabrication of thicker and stiffer electrodes. For this purpose, sandwich electrode technology is the preferred method. Here, two single-sided polyimide thin-film structures are precisely glued together to form a sandwich-like electrode with active contacts on both sides of the structure. For vestibular prostheses, this technology allows a faster and more reliable production of vestibular microelectrodes.