A self-controlled microcontrolled microvalve

Abstract

Integrated microvalves are needed for a broad range of semiconductor-processing-related applications. These include precision mass microflow controllers (μFCs) for dry etch systems, miniature gas chromatography systems for real-time monitoring, point-of-use semiconductor process reactant generators, and compact control systems for mini-environments. This paper reports a pneumatically actuated, integrated silicon microvalve, which was developed as a forerunner to an 8b μFC intended for the precision control of semiconductor process gases in the range from 0.1 to 10 sccm. The structure was designed to be batch-fabricated and compatible with on-chip thermopneumatic actuation. Assembled single-bit μFC devices achieve the targeted flow rate of 5 sccm (determined by an in-line flow channel) at 20 psid (1034 torr). The valve alone may achieve significantly higher flow rates. The leak rate is 0.08 sccm under 26.1 psig actuation pressure, and the valve can seal against pressures greater than 29 psid (1500 torr). © 1998 American Institute of Physics.