Technology aspects of a CMOS neuro-sensor: back end process and packaging

A CMOS-compatible process is presented which allows to realize sensor arrays for non-invasive, extracellular, high density, long term recording of neural activity. A high-permittivity biocompatible dielectric is used to capacitively couple nerve cell-induced biological signals to the CMOS circuitry-based electronic world. The transducer consists of a multi layer of TiO/sub 2/ and ZrO/sub 2/ and is fabricated in the backend of a 0.5 /spl mu/m standard CMOS technology. Living cells are cultured within a specific package on top of the sensor chip. First measurements reveal proper operation of the chip.