Wire-bonding-based vertical microprobe electrode arrays integrated onto high-density microelectrode arrays with active circuitry for extracellular recording

This paper presents a novel wire-bonding technology to manufacture vertical microprobe electrode arrays with uniform tip heights for electrophysiological measurement. The tips of gold microprobes coated with parylene are exposed and leveled at the same time by polishing. Sacrificial supporting material reinforces the probes during polishing. Furthermore, the vertical microprobes are interfaced onto high-density microelectrode arrays (HDMEAs) with active circuitry for amplification and digitization in order to improve signal-to-noise ratio (SNR). The height and diameter of the fabricated vertical microprobes are 150 μm and 31 μm, respectively. The microprobes were evaluated by impedance spectroscopy and chronoamperometric measurements. 75 vertical microprobes were successfully attached on an HDMEA to connect to the on-chip amplification chain. Finally, the microprobes were used to record neuronal signals in an acute cerebellar slices.