Tracy A Pierce

US Patent:

61835625, Feb 6, 2001

Filed:

Dec 23, 1997

Appl. No.:

8/996961

Inventors:

Tracy Lavalle Pierce - Lake Hills TX
Douglas A. Czaja - San Antonio TX

Assignee:

Sony Corporation of Japan - Tokyo
Sony Electronics, Inc. - Park Ridge NJ

International Classification:

C23C 1652

US Classification:

118707

Abstract:

A thermal protection system for a chemical vapor deposition machine (CVD). The system of the present invention includes a thermal sensor for providing a temperature signal corresponding to a CVD chamber temperature, a heating component for heating the CVD chamber, and a controller for regulating the CVD chamber temperature. The controller is coupled to receive the temperature signal and to control the heating component in response thereto. An interlock circuit is coupled between the heating component and the controller. The interlock circuit has an open state and a closed state. A comparison circuit is coupled to receive the temperature signal and coupled to control the interlock circuit, wherein the comparison circuit effects a comparison between the temperature signal and a reference and commands the interlock to the open state when the temperature signal exceeds the reference. In so doing, the comparison circuit protects the CVD chamber from an over-temperature condition that might not otherwise be prevented by the controller.