Abstract: Methods and apparatuses that decouple wafer temperature from pre-heat station residence time, thereby improving wafer-to-wafer temperature uniformity, are provided. The methods involve maintaining a desired temperature by varying the distance between the wafer and a heater. In certain embodiments, the methods involve rapidly approaching a predetermined initial distance and then obtaining and maintaining a desired final temperature using closed loop temperature control. In certain embodiments, a heated pedestal supplies the heat. The wafer-pedestal gap may be modulated may be varied by moving the heated pedestal and/or moving the wafer, e.g., via a movable wafer support. Also in certain embodiments, the closed loop control system includes a real time wafer temperature sensor and a servo controlled linear motor for moving the pedestal or wafer support.
Type:
Grant
Filed:
November 8, 2007
Date of Patent:
November 8, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Michael Nordin, Chris Gage, Shawn Hamilton, Sheldon Templeton