US4193783A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating a silicon single crystal ingot
Assignee: Toshiba Corp
•
Filing: 1978-06-15
•
Granted: 1980-03-18
•
Expires: 1998-06-15
Abstract
Abstract A method of treating a silicon single crystal ingot which comprises the steps of purposely producing lattice strains in a silicon single crystal ingot, annealing the ingot at high temperature, and etching off the surface of the annealed ingot, thereby suppressing the occurrence of lattice defects.
Inventors
- 👤 Yoshiaki Matsushita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:51
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; B; B28; B28D; B28D5/00; C30B15/00; C30B15/20; C30B15/206; C30B33/00; Y; Y10; Y10S; Y10S148/00; Y10S148/061; Y10S65/00; Y10S65/15
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
75 words
A method of preparing silicon wafers from a silicon, single crystal ingot comprising the steps of: purposely producing lattice strains in the surface of the silicon, single crystal ingot, heating the ingot at least 15 hours at a temperature between 1,000° C. and 1,200° C., cooling the ingot etching off the surface of the ingot to at least the depth that the lattice strains are purposely produced, and cutting silicon wafers from the etched ingot.
Claim 2
Independent Claim
75 words
A method of preparing silicon wafers from a silicon, single crystal ingot comprising the steps of: purposely producing lattice strains in the surface of the silicon, single crystal ingot, heating the ingot at least 15 hours at a temperature between 1,000° C. and 1,200° C., cooling the ingot etching off the surface of the ingot to at least the depth that the lattice strains are purposely produced, and cutting silicon wafers from the etched ingot.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein the lattice strains are produced by mechanically grinding the surface of the ingot.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein the lattice strains are produced by implanting ions in the surface of the ingot.
Claim 5
Dependent Claim
22 words
The method of claim 1 wherein the lattice strains are produced by forming an oxide layer on the surface of the ingot.
Claim 6
Independent Claim
78 words
A method of preparing silicon wafers from a silicon, single crystal ingot comprising the steps of: mechanically grinding a surface on the silicon, single crystal ingot to produce lattice strains therein, heating the ingot at least 15 hours at a temperature between 1,000° C. and 1,200° C., cooling the ingot and etching off the surface of the ingot to at least the depth that the lattice strains are purposely produced, and cutting silicon wafers from the etched ingot.
Claim 7
Independent Claim
78 words
A method of preparing silicon wafers from a silicon, single crystal ingot comprising the steps of: mechanically grinding a surface on the silicon, single crystal ingot to produce lattice strains therein, heating the ingot at least 15 hours at a temperature between 1,000° C. and 1,200° C., cooling the ingot and etching off the surface of the ingot to at least the depth that the lattice strains are purposely produced, and cutting silicon wafers from the etched ingot.
Claim 8
Dependent Claim
17 words
The method of claim 5 wherein the silicon, single crystal ingot is prepared by the Czochralski method.
Claim 9
Dependent Claim
18 words
The method of claim 5 wherein the silicon, single crystal ingot is prepared by the float zone method.
Claim 10
Dependent Claim
25 words
The method of claim 5 wherein the step of mechanically grinding comprises grinding the ingot with a centerless grinder to produce a round columnar ingot.
Claim 11
Dependent Claim
16 words
The method of claim 5 wherein the heating temperature is between 1,050° C. and 1,100° C.
Claim 12
Dependent Claim
13 words
The method according to claim 5 wherein the heating temperature is 1,100° C.
Claim 13
Dependent Claim
16 words
The method according to claim 5 wherein the heating is carried out in an oxidizing atmosphere.
Claim 14
Dependent Claim
16 words
The method according to claim 5 wherein the heating is carried out in an inert atmosphere.
Claim 15
Dependent Claim
22 words
The method according to claim 11 wherein the oxidizing atmosphere is selected from the group consisting of dry and wet oxygen gases.
Claim 16
Dependent Claim
17 words
The method according to claim 5 wherein the heating step is continued from 15 to 100 hours.
Claim 17
Dependent Claim
17 words
The method according to claim 5 wherein the heating step is continued from 15 to 36 hours.
Claim 18
Dependent Claim
25 words
The method according to claim 5 wherein an etchant formed of a mixture of hydrofluoric acid and nitric acid is used in the etching step.
Claim 19
Dependent Claim
18 words
The method according to claim 5 wherein about 500 microns is etched off the surface of the ingot.
Claim 20
Dependent Claim
20 words
The method of claim 5 wherein the ingot is cooled at a rate not greater than 50° C. per minute.
Claim 21
Dependent Claim
19 words
The method of claim 1 wherein the lattice strains are produced by mechanically grinding the surface of the ingot.
Claim 22
Dependent Claim
20 words
The method of claim 1 wherein the lattice strains are produced by implanting ions in the surface of the ingot.
Claim 23
Dependent Claim
22 words
The method of claim 3 wherein the lattice strains are produced by forming an oxide layer on the surface of the ingot.
Claim 24
Dependent Claim
21 words
The method according to claim 5 wherein the ingot is cooled at a rate not greater than 100° C. per minute.
Claim 25
Dependent Claim
21 words
The method according to claim 1 wherein the ingot is cooled at a rate not greater than 100° C. per minute.
Claim 26
Dependent Claim
17 words
The method of claim 1 wherein the silicon, single crystal ingot is prepared by the Czochralski method.
Claim 27
Dependent Claim
18 words
The method of claim 1 wherein the silicon, single crystal ingot is prepared by the float zone method.
Claim 28
Dependent Claim
16 words
The method of claim 1 wherein the heating temperature is between 1,050° C. and 1,100° C.
Claim 29
Dependent Claim
13 words
The method according to claim 1 wherein the heating temperature is 1,100° C.
Claim 30
Dependent Claim
16 words
The method according to claim 1 wherein the heating is carried out in an oxidizing atmosphere.
Claim 31
Dependent Claim
16 words
The method according to claim 1 wherein the heating is carried out in an inert atmosphere.
Claim 32
Dependent Claim
22 words
The method according to claim 1 wherein the oxidizing atmosphere is selected from the group consisting of dry and wet oxygen gases.
Claim 33
Dependent Claim
17 words
The method according to claim 1 wherein the heating step is continued from 15 to 100 hours.
Claim 34
Dependent Claim
17 words
The method according to claim 1 wherein the heating step is continued from 15 to 36 hours.
Claim 35
Dependent Claim
25 words
The method according to claim 1 wherein an etchant formed of a mixture of hydrofluoric acid and nitric acid is used in the etching step.
Claim 36
Dependent Claim
18 words
The method according to claim 1 wherein about 500 microns is etched off the surface of the ingot.
Claim 37
Dependent Claim
20 words
The method of claim 1 wherein the ingot is cooled at a rate not greater than 50° C. per minute.
References Cited (Backward Citations)
US3266961A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-03-18 | 1983-09-17 | 1984-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-18 | 1987-09-17 | 1988-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-18 | 1991-09-17 | 1992-03-18 | $7700.00 | Window Closed / Lapsed |