Chia Cheng

US Patent:

7323116, Jan 29, 2008

Filed:

Sep 27, 2004

Appl. No.:

10/951553

Inventors:

Timothy J. Guiney - Battle Ground WA, US
Rao Annapragada - Union City CA, US
Subhash Deshmukh - Vancouver WA, US
Chia Cheng Cheng - San Jose CA, US

Assignee:

Lam Research Corporation - Fremont CA

International Classification:

G01R 31/00

US Classification:

216 61, 216 59, 438 14, 438 16

Abstract:

A method for in-situ monitoring a process in a plasma processing system having a plasma processing chamber is disclosed. The method includes positioning a substrate in the plasma processing chamber. The method also includes striking a plasma within the plasma processing chamber while the substrate is disposed within the plasma processing chamber. The method further includes obtaining a measured self-bias voltage that exists after the plasma is struck, the measured self-bias voltage value having a first value when the plasma is absent and at least a second value different from the first value when the plasma is present. The method also includes correlating the measured self-bias voltage value with an attribute of the process, if the measured self-bias voltage value is outside of a predefined self-bias voltage value envelope.