Electrode array design and fabrication for implantable systems

Abstract: Many medical implants use electrodes to stimulate nerves or muscles, or sense their activity. As more advanced implants such as functional electrical stimulators, cochlear implants and retinal prostheses are developed, requirements for implantable electrodes have become more demanding. Whereas implants such as pacemakers can be made using simple, large, noble-metal electrodes, newer systems such as retinal implants require a complex array of electrodes within a very small enclosure. This necessitates micro-fabrication techniques for both electrodes and substrates with the final assembly needing to retain its biocompatibility. The manufacturing techniques for these new types of arrays push the boundaries of current technologies, both in the formation of microelectrodes and interconnects. This chapter describes processing methods for different types of electrode arrays and discusses their limitations.