A multimicroelectrode fabricated by silicon dry etching

In neuro‐physiology, it is important to record neural impulses from the central neural system simultaneously. For this purpose, a silicon substrate which forms a multimicroelectrode was fabricated and a precise fabrication of a 10 μm thick microelectrode with a 30 μm wide tip was achieved by using Si dry etching. The high‐quality insulation of the electrode in a physiological solution was obtained by using Ta and high‐temperature CVD Si₃N₄. However, Ta itself is not adequate for the recording site because it is oxidized easily in an electrolyte causing the increase of the electrode impedance. Platinum‐black was electroplated on the titanium surface in order to stabilize and reduce the electrode impedance. The interelectrode crosstalk between electrodes and signal attenuation due to the parasitic capacitances were 0.4% and 4.4%, respectively.