Laura M Braun

US Patent:

59333146, Aug 3, 1999

Filed:

Jun 27, 1997

Appl. No.:

8/883068

Inventors:

Albert M. Lambson - Fremont CA
Rick Caple - Newark CA
Eric H. Lenz - San Jose CA
Laura M. Braun - Fremont CA
Ricky Marsh - San Ramon CA

Assignee:

LAM Research Corp. - Fremont CA

International Classification:

H02N 1300

US Classification:

361234

Abstract:

A control circuit configured to control a reference voltage of a reference node of an electrostatic chuck power supply is disclosed. The electrostatic chuck power supply is configured to clamp a substrate to a bipolar electrostatic chuck. The electrostatic chuck has a first buried conductor and a second buried conductor. The electrostatic chuck power supply has a first output configured for being coupled with the first buried plate. The first output has a first output voltage referenced to the reference voltage of the reference node. The electrostatic chuck power supply also has a second output configured for being coupled with the second buried plate. The first output has a first output voltage referenced to the reference voltage of the reference node. The control circuit includes: a first resistor coupled in series with the first output; a first amplifier coupled to the first resistor for sensing a voltage drop across the first resistor; a second resistor in series with said second output; and a second amplifier coupled to the second resistor for sensing a voltage drop across the second resistor.