A novel CMOS-compatible fabrication method for development of an electrostatically actuated micropump

This paper presents the development of a novel micropump actuated electrostatically utilizing CMOS-compatible silicon micromachining fabrication process. The fabrication process consists of six photolithography steps and five chemical vapor depositions. Etching of the sacrificial oxide layer for the diaphragm chamber, microchannels and inlet/outlet reservoirs are achieved using etch-release holes perforated on the polysilicon layer, similar to via holes used in IC-fabrication method. The sacrificial oxide etching and encapsulation of the etch-release holes have been successfully accomplished by using BOE etchants for 17 minutes and by growing LPCVD silicon nitride of thickness 0.9 μm respectively. Accomplishing this feat enables CMOS-compatible electrostatically actuated micropump to be developed with potential integration with CMOS-based sensors, readout circuits and packaging, on a single wafer.