Patent US4868133A successfully refreshed from Google Patents.
US4868133A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor wafer fabrication with improved control of internal gettering sites using RTA
Assignee: Dns Electronic Materials Inc
•
Filing: 1989-03-16
•
Granted: 1989-09-19
•
Expires: 2009-03-16
Abstract
Abstract The concentration of internal gettering sites within a semiconductor wafer is controlled by two-step thermal processing. In a concentration reduction phase, the wafer is rapidly heated to an elevated temperature in the range from about 900 DEG to 1350 DEG C., resulting in the partial or total dissolution of precipitable impurities within the wafer. In a concentration enhancement step, the wafers are subjected to a relatively low temperature anneal process where the density of potential internal gettering sites is increased. By properly controlling the processing temperatures and treatment times, the two steps may be performed in either order to obtain wafers having internal gettering site concentrations within a desired range.
Inventors
- 👤 Walter Huber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:01
CPC Classifications
H; H10; H10P; H10P36/00; H10P36/20; H10P36/03; Y; Y10; Y10S; Y10S148/00; Y10S148/024; Y10S148/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
118 words
A method for controlling the oxygen cluster concentration within a silicon substrate, said method comprising performing the following steps in the order set forth: heating the substrate to an intermediate temperature in the range from about 600° C. to 750° C. for a time period sufficient to precipitate a concentration of oxygen clusters within the substrate; radiantly heating the substrate to an elevated temperature in the range from about 1000° C. to 1250° C. at a rate of at least about 25° C. per second to dissolve oxygen clusters leaving a concentration in the range from about 10 5 to 5×10 6 /cm 2 within the substrate; and cooling the substrate to a temperature below about 600° C.
Claim 2
Independent Claim
118 words
A method for controlling the oxygen cluster concentration within a silicon substrate, said method comprising performing the following steps in the order set forth: heating the substrate to an intermediate temperature in the range from about 600° C. to 750° C. for a time period sufficient to precipitate a concentration of oxygen clusters within the substrate; radiantly heating the substrate to an elevated temperature in the range from about 1000° C. to 1250° C. at a rate of at least about 25° C. per second to dissolve oxygen clusters leaving a concentration in the range from about 10 5 to 5×10 6 /cm 2 within the substrate; and cooling the substrate to a temperature below about 600° C.
Claim 3
Dependent Claim
16 words
A method as in claim 1, wherein the radiant heating is performed in an inert atmosphere.
Claim 4
Dependent Claim
19 words
A method as in claim 1, wherein the radiant heating rate is at least about 10° C. per second.
Claim 5
Dependent Claim
24 words
A method as in claim 1, wherein the substrate is held at the elevated temperature for a period of at least about 1 second.
Claim 6
Dependent Claim
22 words
A method as in claim 4, wherein the substrate is cooled at a rate of at least about 10° C. per second.
Claim 7
Dependent Claim
21 words
A method as in claim 1, wherein the substrate is held at the intermediate temperature for at least about 15 minutes.
References Cited (Backward Citations)
US4314595A
Cited
US4376657A
Cited
EP0060676A2
Cited
JPS57201032A
Cited
JPS5821829A
Cited
JPS58103123A
Cited
US4432809A
Cited
JPS58204541A
Cited
US4608095A
Cited
US4548654A
Cited
US4661166A
Cited
US4544418A
Cited
US4637123A
Cited
US4622082A
Cited
JPS6120337A
Cited
US4566913A
Cited
US4732874A
Cited
US4743569A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |