Fabrication and characterization of a novel microvalve for microfluidic applications

Abstract

We present a novel micromachined passive valve for fluid flow control within microfluidic systems. Forward flow through the valve is in the opposite direction compared to other published designs, and the valve thus has considerable potential for integrated microfluidic devices or systems. In applications such as micropumps, the inlet and outlet valves can be formed on the same surface, removing the need for precision processing on both wafer surfaces. The fabricated valve consists of three major layers, namely: a top bridge with an inlet aperture; a movable plate with four supporting arms; and an underlying substrate with an outlet aperture. The structure and operation of the device is presented, together with a detailed description of the fabrication process. The fabricated valves are characterized for fluid flow under forward and reverse pressures. In the forward direction, a water flow rate of 1920 µl/min is measured at a pressure of 14.1 kPa, and the reverse leakage is less than 8 µl/min.