A VALVE-LESS PLANAR PUMP ISOTROPICALLY ETCHED IN SILICON

The first valve-less diffuser fluid pump in silicon is presented. It c onsists of a planar double-chamber arrangement fabricated in a silicon wafer anodically bonded to a glass wafer. The pump uses fluid-directi ng diffuser-nozzle elements which have a depth of 24-48 mu m and a nec k width of 88-104 mu m. The pump chamber diameter is 6 mm. Pump caviti es and diffuser-nozzle elements are etched with an isotropic HNA silic on etch. Pumps with three different diffuser lengths are compared reac hing a maximum pump capacity of 230 mu l min(-1) and a maximum pump pr essure of 1.7 m H2O at a resonance frequency of 1318 Hz for methanol.