US4417943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for controlling the oxygen level of silicon rods pulled according to the Czochralski technique
Assignee: International Business Machines Corp
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Filing: 1981-05-22
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Granted: 1983-11-29
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Expires: 2001-05-22
Abstract
Abstract A method for controlling the oxygen concentration profile of a rod of crystalline material such as silicon being pulled from a melt in a crucible includes varying the crucible rotation speed during the pulling process. In a preferred embodiment, the average oxygen concentration profile of a rod pulled at a constant crucible rotation speed is measured and then this information is used in growing another rod by controlling the crucible rotation speed during the pulling process so that its slope is opposite to the slope of the measured average oxygen concentration profile.
Inventors
- 👤 Combronde Jacques
- 👤 Jean-Claude Felix
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:01
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; C30B15/00; C30B15/30; C30B15/305; Y; Y10; Y10S; Y10S117/00; Y10S117/916
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
107 words
An improved method for the production of a silicon monocrystalline rod grown according to the Czochralski method, in which the oxygen content (O 2 ) is relatively high and maintained substantially constant throughout the length, L, of the rod at a desired value, the improvement comprising: determining the average oxygen content profile (O 2 ) of the rod specific to the pulling equipment used when grown with a constant crucible rotation speed (V RC ) O =R O , and controlling the crucible rotation speed V RC during the pulling so that its slope is opposite to the slope of the previously measured average oxygen concentration profile.
Claim 2
Dependent Claim
107 words
An improved method for the production of a silicon monocrystalline rod grown according to the Czochralski method, in which the oxygen content (O 2 ) is relatively high and maintained substantially constant throughout the length, L, of the rod at a desired value, the improvement comprising: determining the average oxygen content profile (O 2 ) of the rod specific to the pulling equipment used when grown with a constant crucible rotation speed (V RC ) O =R O , and controlling the crucible rotation speed V RC during the pulling so that its slope is opposite to the slope of the previously measured average oxygen concentration profile.
Claim 3
Dependent Claim
27 words
A method as described in claim 1 including the step of controlling the rotation speed by a computer which has the required rotation speed profile in memory.
Claim 4
Dependent Claim
19 words
A method as described in claim 1 including the steps of increasing the rotational speed during the whole processing.
Claim 5
Dependent Claim
52 words
A method as described in claim 1 including the steps of increasing the rotational speed while the first third of the rod is being formed, maintaining a constant speed while the second third of the rod is being formed and decreasing the speed while the remaining third of the rod is formed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-11-28 | 1987-05-30 | 1987-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-28 | 1991-05-30 | 1991-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-28 | 1995-05-30 | 1995-11-29 | $7700.00 | Window Closed / Lapsed |