Design, microfabrication and testing of a CMOS compatible bistable electromagnetic microvalve with latching/unlatching mechanism on a single wafer

Abstract

This paper reports our work on the design, microfabrication and testing of a novel bistable electromagnetically actuated microvalve that is fully fabricated by surface micromachining on a single silicon wafer with a potentially CMOS compatible process. The microvalve has an overall diameter of 1600 µm and an overall height of 600 µm that includes the thickness of the silicon wafer. The microvalve consists of four main components: a soft magnetic (NiFe) base, an Au microcoil, a CoNiMnP permanent magnet and a soft magnetic (NiFe) membrane with supported legs. The latching and unlatching mechanism of the microvalve governs the bistable positions of the membrane. The microvalve was tested for its performance to open/unlatch and close/latch a flow of deionized water at flow rates of 10–50 µl min−1. The microvalve operates at a current of 0.43 A, and its power and energy consumption are of the order of 1.6 W and 16 mJ, respectively. The microvalve has a response time of 10 ms and a burst pressure of 7.8 kPa.