Modification of a CMOS microelectrode array for a bioimpedance imaging system

A complete microsensor array with integrated circuitry, fabricated using a conventional complementary metal oxide semiconductor (CMOS) process is presented. This sensor array is the first step towards a system-on-chip design intended for making cellular impedance measurements in a tissue culture. The microelectrodes that make up the sensor array were passivated using a modified electroless gold plating process. The process plates a layer of gold onto the native aluminium electrodes so that they are suitable for performing the cellular impedance measurement experiment. Successful trials were achieved from the plating process with uniform plating coverage over all the exposed aluminium surfaces.