An electromagnetic actuated on/off microvalve fabricated on top of a single wafer

Abstract

This paper reports our work on an electromagnetically actuated on/off microvalve. The microvalve consists of three main components: a soft magnetic base, a Au microcoil and a soft magnetic dome with supported legs. The microvalve is built entirely by surface micromachining on top of a single silicon wafer. It has an overall diameter of 1100 µm. It has an overall height of 600 µm, which includes the thickness of the silicon substrate. By turning on or off the current to the microcoil, the microvalve closes or opens the flow of liquid through its orifice. The on/off microvalve was tested for its performance in the flow of 50% diluted methanol with water at the flow rate of 1 µl min−1. The operational power of the microvalve was in the range of 0.3–1.2 W. The operational current was in the range of 0.27–0.6 A. The microvalve has a leaking rate in the order of 0.003 µl min−1.