A high-yield IC-compatible multichannel recording array

This paper reports the development of a multielectrode recording array for use in studies of information processing in the central nervous system and in the closed-loop control of neural prostheses. The probe utilizes a silicon supporting carrier which is defined using a deep boron diffusion and an anisotropic etch stop. This substrate supports an array of polysilicon or tantalum thin-film conductors insulated above and below with silicon nitride and silicon dioxide. Typical probe dimensions include a length of 3 mm, shank width of 50 µm, and a thickness of 15 µm. These structures are capable of simultaneous high-amplitude multichannel recording of neural activity in the cortex. The probe fabrication process requires only four masks and is single-sided using wafers of normal thickness, resulting in yields which exceed 80 percent. The process is also compatible with the inclusion of on-chip MOS circuitry for signal amplification and multiplexing. A complete ten-channel signal processor which requires only three external probe leads is being developed.