Metallization on 3-D microstructures using spray coating for high performance micro direct methanol fuel cell (μDMFC)

High efficient micro electrochemical devices are realized by the increase of the electrode surface areas keeping the chip size. Use of the 3D electrodes instead of the planar electrodes is quite effective for this purpose. To realize a metal pattern on 3D structures, spray coating method was utilized and the optimum condition to achieve good step coverage was observed. Good step coverage of photoresist was obtained on the obtuse corner formed by anisotropic wet etching of (100) silicon and even vertical corner formed by deep RIE. We applied this method to fabricate a high performance micro direct methanol fuel cell (μDMFC). The open circuit voltage of 548mV and the maximum power density of 0.72mW/cm² were obtained at room temperature with 2M methanol.