US5242831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for evaluating roughness on silicon substrate surface
Assignee: Sharp Corp
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Filing: 1992-07-07
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Granted: 1993-09-07
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Expires: 2012-07-07
Abstract
Abstract A method for evaluating surface micro roughness of a silicon substrate includes the steps of soaking the silicon substrate in a mixture of hydrochloric acid of 30 to 40 vol %, hydrogen peroxide solution of 30 to 40 vol % and deionized water whose volume ratio is approximately 1:1:16.7, and measuring an amount of chlorine element incorporated into native oxide film on the silicon surface through the soaking process to evaluate the degree of the micro roughness on the silicon substrate surface.
Inventors
- 👤 Ichiro Oki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:34
CPC Classifications
G; G01; G01N; G01N1/00; G01N1/28; G01N1/32; Y; Y10; Y10T; Y10T436/00; Y10T436/19
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
126 words
A method for evaluating surface micro roughness of a silicon substrate comprising the steps of: soaking the silicon substrate in a mixture of hydrochloric acid of 30 to 40 vol %, hydrogen peroxide solution of 30 to 40 vol % and deionized water whose volume ratio is approximately 1:1:16.7; measuring an amount of chlorine element deposited on the silicon surface through the soaking process; and evaluating the degree of the micro roughness on the silicon substrate surface by comparing the measured chlorine amount with a known chlorine amount measured for silicon substrates of known surface micro roughness, said known chlorine amounts being obtained by performing said soaking step on said silicon substrates of known surface micro roughness and measuring the chlorine amount of each substrate thereafter.
Claim 2
Independent Claim
126 words
A method for evaluating surface micro roughness of a silicon substrate comprising the steps of: soaking the silicon substrate in a mixture of hydrochloric acid of 30 to 40 vol %, hydrogen peroxide solution of 30 to 40 vol % and deionized water whose volume ratio is approximately 1:1:16.7; measuring an amount of chlorine element deposited on the silicon surface through the soaking process; and evaluating the degree of the micro roughness on the silicon substrate surface by comparing the measured chlorine amount with a known chlorine amount measured for silicon substrates of known surface micro roughness, said known chlorine amounts being obtained by performing said soaking step on said silicon substrates of known surface micro roughness and measuring the chlorine amount of each substrate thereafter.
Claim 3
Dependent Claim
35 words
A method for evaluating surface micro roughness of a silicon substrate according to claim 1, wherein the amount of chlorine element is measured by a total reflection X-ray fluorescence analysis or a X-ray micro analyzer.
Claim 4
Dependent Claim
40 words
A method for evaluating surface micro roughness of a silicon substrate according to claim 1, wherein the amount of chlorine element is evaluated by measuring an amount of electric charge caused by chlorine ions incorporated into a native oxide film.
Claim 5
Dependent Claim
27 words
A method for evaluating surface roughness of a silicon substrate according to claim 3, wherein the amount of electric charge is measured by a surface charge analyzer.
Claim 6
Dependent Claim
31 words
A method for evaluating surface micro roughness of a silicon substrate according to claim 1, wherein the soaking step employs a soaking temperature of about 25° C. to about 40° C.
Claim 7
Dependent Claim
30 words
A method for evaluating surface micro roughness of a silicon substrate according to claim 1, wherein the soaking step employs a soaking time of about 5 to about 20 minutes.
References Cited (Backward Citations)
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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) | 1996-09-06 | 1997-03-08 | 1997-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-06 | 2001-03-08 | 2001-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-06 | 2005-03-08 | 2005-09-07 | $7700.00 | Window Closed / Lapsed |