Claims
- 1. A method of maintaining uniform temperature on a semiconductor wafer during high temperature processing of the wafer comprising:positioning the wafer on one or more spacers extending upwardly from a susceptor so that the wafer is substantially thermally decoupled from the susceptor; heating the wafer and susceptor with an upper heat source spaced above the wafer and a lower heat source spaced below the susceptor; maintaining relatively constant the ratio of heat provided by the upper and lower heat sources when the wafer and susceptor are both at a desired temperature; and when rapidly changing the temperature of the wafer and the susceptor, changing said ratio so as to maintain the wafer and the susceptor at substantially the same temperature as their temperatures are changing.
- 2. The method of claim 1, wherein said ratio changing includes reducing the percentage of heat provided from the upper source when rapidly increasing the temperature of the wafer and the susceptor.
- 3. The method of claim 2, wherein said ratio changing includes increasing the percentage of heat provided from the upper heat source, when allowing the temperature of the wafer and the susceptor to decrease, while continuing to provide some heat to the wafer and the susceptor to maintain uniformity.
- 4. The method of claim 1, wherein the spacers each comprise a flat upper surface.
- 5. The method of claim 4, wherein the flat upper surface has a width between about 0.025 inch and 0.045 inch.
- 6. The method of claim 5, wherein the spacers further comprise rounded shoulders adjacent the flat upper surface.
RELATED APPLICATIONS
The present application is a is a divisional application of application Ser. No. 08/923,241 filed Sep. 4, 1997 now U.S. Pat. No. 6,113,702, which claims the priority benefit of Provisional Application No. 60/039,850 filed Mar. 5, 1997 and is a Continuation-In-Part of application Ser. No. 08/788,817 filed Jan. 23, 1997 (now abandoned), which is a Continuation-In-Part of application Ser. No. 08/706,069 filed Aug. 30, 1996 (issued Apr. 25, 2000 as U.S. Pat. No. 6,053,982) which claims the priority benefit of Provisional Application No. 60/003,132, filed Sep. 1, 1995.
US Referenced Citations (91)
Foreign Referenced Citations (6)
Number |
Date |
Country |
0 448 346 |
Sep 1991 |
EP |
0 452 779 |
Oct 1991 |
EP |
0 592 017 |
Apr 1994 |
EP |
0 651 424 |
May 1995 |
EP |
0 657 918 |
Jun 1995 |
EP |
2181458 |
Apr 1987 |
GB |
Provisional Applications (2)
|
Number |
Date |
Country |
|
60/039850 |
Mar 1997 |
US |
|
60/003132 |
Sep 1995 |
US |
Continuation in Parts (2)
|
Number |
Date |
Country |
Parent |
08/788817 |
Jan 1997 |
US |
Child |
08/923241 |
|
US |
Parent |
08/706069 |
Aug 1996 |
US |
Child |
08/788817 |
|
US |