PNEUMATIC MICROVALVE BASED ON SILICON MICROMACHINING

Abstract

A silicon microvalve to control fine gas flow was developed for advanced semiconductor fabrication processes. The valve is operated by a combination of pneumatic and electrostatic forces. It is composed of a glass-silicon-silicon-glass structure using silicon bulk micromachining. An anodically bonded glass-silicon combination is further bonded to another glass-silicon combination using Au-Si eutectic bonding. The structure has a built-in bias force for closing the valve normally. A polished silicon surface is utilized as a valve seat in order to decrease the gas leakage. The valve has corrugated diaphragms to increase maximum gas flow rate. The gas flow rate could be controlled from 0.1 sccm to 35 sccm at the the inlet pressure range of 0.13-0.66kgf/cm². This microvalve can be used in the temperature range from 25 to 120°C.