Figure 1

The manufacturing procedures of dual metal- layer microelectrode array. (a) Evaporation of aluminum sacrificial layer onto the silicon wafer and spin-coating of the first PSPI film; (b) Sputtering and patterning of the lower Ti/Pt layer; (c) Spin-coating and patterning of the middle PSPI layer to expose half of the stimulating electrodes and bonding pads; (d) Sputtering and patterning upper Ti/Pt layer; (e) Spin-coating and patterning of the upper PSPI layer to expose the whole stimulating electrodes and bonding pads; (f) Microelectrode array released from the silicon substrate.