Microvalves are miniature valves used to control fluid flows at low flow rates. Such valves and other micro-electromechanical (MEMS) devices are conventionally used in several industrial and professional applications where it is important to precisely regulate the flow of small quantities of gases or liquids. For example, microvalves are used for some types of medical research (such as DNA research), medical treatments, and other types of applications that involve metering fluids at low flow rates.
Some conventional microvalves are formed directly in a semiconductor substrate (such as silicon) using techniques generally similar to those used to form integrated circuits. Such valves typically include a flexible diaphragm that opens and closes a fluid orifice when selected voltages are applied to the valve. Examples of such valves are disclosed in U.S. Pat. No. 5,810,325 to Carr, which is incorporated herein in its entirety by reference.
One drawback with some conventional diaphragm microvalves of the type described above is that the valves may fail because the diaphragm can fracture or deform after repeated uses. Another drawback is that conventional diaphragms typically do not exert a large sealing force to close the fluid orifice. Accordingly, such diaphragms may not be suitable for valves that regulate high pressure fluids.