Patent US4432809A successfully refreshed from Google Patents.
US4432809A
Expired / Lapsed
US
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Method for reducing oxygen precipitation in silicon wafers
Assignee: International Business Machines Corp
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Filing: 1981-12-31
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Granted: 1984-02-21
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Expires: 2001-12-31
Abstract
Abstract The rate of oxygen precipitation in a semiconductor wafer during heat treatment is reduced by quickly inserting the wafer into a furnace which has been preheated to the heat treatment temperature. After performing the heat treatment, the wafer is slowly cooled to prevent warpage or cracking.
Inventors
- 👤 Patrick W. Chye
- 👤 Eric W. Hearn
- 👤 Murlidhar V. Kulkarni
- 👤 Gary Markovits
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:59
CPC Classifications
H; H10; H10P; H10P36/00; H10P36/20
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
104 words
A method of retarding oxygen precipitation and preventing warpage in a semiconductor wafer which is subject to heat treatment at a predetermined temperature during the manufacture of semiconductor circuits thereon, comprising the steps of: preheating a furnace to the predetermined heat treatment temperature, inserting the wafer into the preheated furnace in a manner which immediately exposes said semiconductor wafer to said predetermined heat treatment temperature and causes said semiconductor wafer to rapidly heat up to said predetermined heat temperature, maintaining the furnace at said predetermined heat treatment temperature for about ninety minutes, and slowly cooling the wafer at the end of said heat treatment.
Claim 2
Independent Claim
104 words
A method of retarding oxygen precipitation and preventing warpage in a semiconductor wafer which is subject to heat treatment at a predetermined temperature during the manufacture of semiconductor circuits thereon, comprising the steps of: preheating a furnace to the predetermined heat treatment temperature, inserting the wafer into the preheated furnace in a manner which immediately exposes said semiconductor wafer to said predetermined heat treatment temperature and causes said semiconductor wafer to rapidly heat up to said predetermined heat temperature, maintaining the furnace at said predetermined heat treatment temperature for about ninety minutes, and slowly cooling the wafer at the end of said heat treatment.
Claim 3
Independent Claim
121 words
A method of retarding oxygen precipitation and preventing warpage in a semiconductor wafer which is subject to heat treatment at a predetermined temperature during the manufacture of semiconductor circuits thereon, comprising the steps of: inserting the wafer into a furnace, the temperature of which may be increased to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second, increasing the furnace temperature to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second to thereby increase the wafer temperature to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second, performing the heat treatment, and slowly cooling the wafer at the end of said heat treatment.
Claim 4
Independent Claim
121 words
A method of retarding oxygen precipitation and preventing warpage in a semiconductor wafer which is subject to heat treatment at a predetermined temperature during the manufacture of semiconductor circuits thereon, comprising the steps of: inserting the wafer into a furnace, the temperature of which may be increased to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second, increasing the furnace temperature to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second to thereby increase the wafer temperature to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second, performing the heat treatment, and slowly cooling the wafer at the end of said heat treatment.
Claim 5
Dependent Claim
35 words
The method of claim 1 or 2 wherein the predetermined heat treatment temperature is greater than 800° C. and wherein the wafer is slowly cooled from the predetermined heat treatment temperature to below 800° C.
Claim 6
Dependent Claim
20 words
The method of claim 1 or 2 wherein the wafer is slowly cooled at a rate less than 15° C./minute.
Claim 7
Independent Claim
103 words
A method of retarding oxygen precipitation in a semiconductor wafer having interstitial oxygen content greater than 33 parts per million, by performing the following sequence of steps prior to fabricating semiconductor circuits thereon: preheating a furnace to a temperature above 800° C., inserting the wafer into the preheated furnace in a manner which immediately exposes the semiconductor wafer to the temperature of the preheated furnace and causes said semiconductor wafer to rapidly heat up to the temperature of the preheated furnace, maintaining the furnace at said temperature above 800° C. for about ninety minutes, and slowly cooling the wafer to below 800° C.
Claim 8
Independent Claim
103 words
A method of retarding oxygen precipitation in a semiconductor wafer having interstitial oxygen content greater than 33 parts per million, by performing the following sequence of steps prior to fabricating semiconductor circuits thereon: preheating a furnace to a temperature above 800° C., inserting the wafer into the preheated furnace in a manner which immediately exposes the semiconductor wafer to the temperature of the preheated furnace and causes said semiconductor wafer to rapidly heat up to the temperature of the preheated furnace, maintaining the furnace at said temperature above 800° C. for about ninety minutes, and slowly cooling the wafer to below 800° C.
Claim 9
Independent Claim
110 words
A method of retarding oxygen precipitation in a semiconductor wafer having interstitial oxygen content greater than 33 parts per million, by performing the following sequence of steps prior to fabricating semiconductor circuits thereon: inserting the wafer into a furnace, the temperature of which may be rapidly increased to a temperature above 800° C. at a rate exceeding several hundred degrees centigrade per second, rapidly increasing the furnace temperature to above 800° C. at a rate exceeding several hundred degrees centigrade per second to thereby increase the wafer to above 800° C. at a rate exceeding several hundred degrees centigrade per second, and slowly cooling the wafer to below 800° C.
Claim 10
Independent Claim
110 words
A method of retarding oxygen precipitation in a semiconductor wafer having interstitial oxygen content greater than 33 parts per million, by performing the following sequence of steps prior to fabricating semiconductor circuits thereon: inserting the wafer into a furnace, the temperature of which may be rapidly increased to a temperature above 800° C. at a rate exceeding several hundred degrees centigrade per second, rapidly increasing the furnace temperature to above 800° C. at a rate exceeding several hundred degrees centigrade per second to thereby increase the wafer to above 800° C. at a rate exceeding several hundred degrees centigrade per second, and slowly cooling the wafer to below 800° C.
Claim 11
Independent Claim
104 words
A method of retarding oxygen precipitation in a semiconductor wafer having interstitial oxygen content greater than 33 parts per million, by performing the following sequence of steps prior to fabricating semiconductor circuits thereon: preheating a furnace to a temperature above 800° C., inserting the wafer into the preheated furnace in a manner which immediately exposes the semiconductor wafer to the temperature of the preheated furnace and causes said semiconductor wafer to rapidly heat up to the temperature of the preheated furnace, and maintaining the furnace at said temperature above 800° C. for about ninety minutes, and uniformly cooling the wafer to below 800° C.
Claim 12
Independent Claim
104 words
A method of retarding oxygen precipitation in a semiconductor wafer having interstitial oxygen content greater than 33 parts per million, by performing the following sequence of steps prior to fabricating semiconductor circuits thereon: preheating a furnace to a temperature above 800° C., inserting the wafer into the preheated furnace in a manner which immediately exposes the semiconductor wafer to the temperature of the preheated furnace and causes said semiconductor wafer to rapidly heat up to the temperature of the preheated furnace, and maintaining the furnace at said temperature above 800° C. for about ninety minutes, and uniformly cooling the wafer to below 800° C.
Claim 13
Independent Claim
112 words
A method of retarding oxygen precipitation in a semiconductor wafer having interstitial oxygen content greater than about 33 parts per million, by performing the following sequence of steps prior to fabricating semiconductor circuits thereon: inserting the wafer into a furnace, the temperature of which may be rapidly increased to a temperature above 800° C. at a rate exceeding several hundred degrees centigrade per second, rapidly increasing the furnace temperature to above 800° C. at a rate exceeding several hundred degrees centigrade per second to thereby increase the wafer temperature to above 800° C. at a rate exceeding several hundred degrees centigrade per second, and uniformly cooling the wafer to below 800° C.
Claim 14
Independent Claim
112 words
A method of retarding oxygen precipitation in a semiconductor wafer having interstitial oxygen content greater than about 33 parts per million, by performing the following sequence of steps prior to fabricating semiconductor circuits thereon: inserting the wafer into a furnace, the temperature of which may be rapidly increased to a temperature above 800° C. at a rate exceeding several hundred degrees centigrade per second, rapidly increasing the furnace temperature to above 800° C. at a rate exceeding several hundred degrees centigrade per second to thereby increase the wafer temperature to above 800° C. at a rate exceeding several hundred degrees centigrade per second, and uniformly cooling the wafer to below 800° C.
Claim 15
Independent Claim
29 words
The method of claims 5, 6, 7 or 8 where the claimed sequence of steps is performed on the semiconductor wafer three times prior to fabricating semiconductor circuits thereon.
Claim 16
Independent Claim
104 words
A method of retarding oxygen precipitation and preventing warpage in a semiconductor wafer which is subject to heat treatment at a predetermined temperature during the manufacture of semiconductor circuits thereon, comprising the steps of: preheating a furnace to the predetermined heat treatment temperature, inserting the wafer into the preheated furnace in a manner which immediately exposes said semiconductor wafer to said predetermined heat treatment temperature and causes said semiconductor wafer to rapidly heat up to said predetermined heat temperature, maintaining the furnace at said predetermined heat treatment temperature for about ninety minutes, and uniformly cooling the wafer at the end of said heat treatment.
Claim 17
Independent Claim
104 words
A method of retarding oxygen precipitation and preventing warpage in a semiconductor wafer which is subject to heat treatment at a predetermined temperature during the manufacture of semiconductor circuits thereon, comprising the steps of: preheating a furnace to the predetermined heat treatment temperature, inserting the wafer into the preheated furnace in a manner which immediately exposes said semiconductor wafer to said predetermined heat treatment temperature and causes said semiconductor wafer to rapidly heat up to said predetermined heat temperature, maintaining the furnace at said predetermined heat treatment temperature for about ninety minutes, and uniformly cooling the wafer at the end of said heat treatment.
Claim 18
Independent Claim
121 words
A method of retarding oxygen precipitation and preventing warpage in a semiconductor wafer which is subject to heat treatment at a predetermined temperature during the manufacture of semiconductor circuits thereon, comprising the steps of: inserting the wafer into a furnace, the temperature of which may be increased to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second, increasing the furnace temperature to a predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second to thereby increase the wafer temperature to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second, performing the heat treatment, and uniformly cooling the wafer at the end of said heat treatment.
Claim 19
Independent Claim
121 words
A method of retarding oxygen precipitation and preventing warpage in a semiconductor wafer which is subject to heat treatment at a predetermined temperature during the manufacture of semiconductor circuits thereon, comprising the steps of: inserting the wafer into a furnace, the temperature of which may be increased to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second, increasing the furnace temperature to a predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second to thereby increase the wafer temperature to the predetermined heat treatment temperature at a rate exceeding several hundred degrees centigrade per second, performing the heat treatment, and uniformly cooling the wafer at the end of said heat treatment.
Claim 20
Independent Claim
34 words
The method of claims 10 or 11 wherein the predetermined heat treatment temperature is greater than 800° C. and wherein the wafer is uniformly cooled from the predetermined heat treatment to below 800° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-20 | 1987-08-22 | 1988-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-20 | 1991-08-22 | 1992-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-20 | 1995-08-22 | 1996-02-21 | $7700.00 | Window Closed / Lapsed |