Flexible BIOMEMS with electrode arrangements on front and back side as key component in neural prostheses and biohybrid systems

Micromachined devices with substrate-integrated electrodes are the key component in implantable microsystems—one important group of BIOMEMS for recording of neural signals or electrical stimulation of nerves. So far, electrodes have been located on only one side of the microsystems. In this paper a technology has been developed to fabricate multichannel microelectrodes that are located on the topside and the backside of a flexible device. The process technology for polyimide-based devices is described. Prototypes of shaft electrodes with double-sided electrodes have been fabricated and characterized with means of impedance spectroscopy. Results are discussed on scanning electron microscopy, cross sections and electrochemical characterizations of the electrodes.