US4454004A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Utilizing controlled illumination for creating or removing a conductive layer from a SiO2 insulator over a PN junction bearing semiconductor
Assignee: HP Inc
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Filing: 1983-02-28
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Granted: 1984-06-12
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Expires: 2003-02-28
Abstract
Abstract A new phenomenon in integrated circuit etch processing is presented, explained and utilized to permit better removal of layers overlying integrated circuit structures, and if desired, the formation of conductive layers on such structures by a less complicated and lower temperature process than has been possible by conventional techniques.
Inventors
- 👤 David E. Hackleman
- 👤 Ralph H. Nielsen, Jr.
- 👤 Marzio A. Leban
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:58
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
86 words
In a method for chemical etching with an aqueous acidic fluoride etching solution of a region of silicon dioxide over a semiconductor substrate having a P-N junction, the steps comprising: controlling illumination by light of the semiconductor substrate by substantially excluding light from the region of silicon dioxide being etched during a time just prior to the chemical etching of the region of silicon dioxide; and etching the region of silicon dioxide while continuing to substantially exclude light from the region of silicon dioxide being etched.
Claim 2
Dependent Claim
86 words
In a method for chemical etching with an aqueous acidic fluoride etching solution of a region of silicon dioxide over a semiconductor substrate having a P-N junction, the steps comprising: controlling illumination by light of the semiconductor substrate by substantially excluding light from the region of silicon dioxide being etched during a time just prior to the chemical etching of the region of silicon dioxide; and etching the region of silicon dioxide while continuing to substantially exclude light from the region of silicon dioxide being etched.
Claim 3
Dependent Claim
24 words
In a method as in claim 1 wherein the illumination intensity of the silicon dioxide region being etched is no greater than one foot-candle.
Claim 4
Dependent Claim
38 words
In a method as in claim 1 wherein the time just prior to the chemical etching of the region of silicon dioxide comprises sufficient time for photo-produced electroactive species in and on the semiconductor substrate to reach equilibrium.
Claim 5
Dependent Claim
22 words
In a method as in claim 3 wherein the equilibrium time comprises a period substantially equal to or greater than one minute.
Claim 6
Dependent Claim
102 words
In a method for chemical etching with an aqueous acidic fluoride etching solution of a region of silicon dioxide over a semiconductor substrate having a P-N junction, the steps comprising: controlling illumination by light of the semiconductor substrate in the region of silicon dioxide being etched during a time just prior to the chemical etching of the region of silicon dioxide for sufficient time for photo-produced electroactive species in and on the semiconductor substrate to reach equilibrium; and etching the region of silicon dioxide while continuing to maintain control of the illumination by light of the region of silicon dioxide being etched.
Claim 7
Dependent Claim
102 words
In a method for chemical etching with an aqueous acidic fluoride etching solution of a region of silicon dioxide over a semiconductor substrate having a P-N junction, the steps comprising: controlling illumination by light of the semiconductor substrate in the region of silicon dioxide being etched during a time just prior to the chemical etching of the region of silicon dioxide for sufficient time for photo-produced electroactive species in and on the semiconductor substrate to reach equilibrium; and etching the region of silicon dioxide while continuing to maintain control of the illumination by light of the region of silicon dioxide being etched.
Claim 8
Dependent Claim
22 words
In a method as in claim 5 wherein the equilibrium time comprises a period substantially equal to or greater than one minute.
Claim 9
Dependent Claim
31 words
In a method as in claim 5 wherein the controlling the illumination by light comprises darkening the region of silicon dioxide being etched so that substantially no photons are present therein.
Claim 10
Dependent Claim
20 words
In a method as in claim 7 wherein the darkening comprises maintaining an illumination intensity no greater than one foot-candle.
Claim 11
Dependent Claim
39 words
In a method as in claim 5 wherein controlling the illumination by light comprises filtering the light that illuminates the region of silicon dioxide being etched to substantially exclude light which produces photoelectrons in and on the semiconductor substrate.
Claim 12
Dependent Claim
20 words
In a method as in claim 9 wherein the filtering excludes light not in a bandpass wavelength of 200-500 nanometers.
Claim 13
Dependent Claim
103 words
In a method for chemical etching with an aqueous acidic fluoride etching solution of a region of silicon dioxide over a semiconductor substrate having a P-N junction, the steps comprising: illuminating the semiconductor substrate in the region of silicon dioxide being etched during a time just prior to the chemical etching of the region of silicon dioxide; and etching the region of silicon dioxide while continuing to illuminate the region of silicon dioxide being etched to create photoproduced electroactive species in and on the semiconductor substrate whereby a conductive reduced species of the silicon dioxide is created in the region of silicon dioxide.
Claim 14
Dependent Claim
103 words
In a method for chemical etching with an aqueous acidic fluoride etching solution of a region of silicon dioxide over a semiconductor substrate having a P-N junction, the steps comprising: illuminating the semiconductor substrate in the region of silicon dioxide being etched during a time just prior to the chemical etching of the region of silicon dioxide; and etching the region of silicon dioxide while continuing to illuminate the region of silicon dioxide being etched to create photoproduced electroactive species in and on the semiconductor substrate whereby a conductive reduced species of the silicon dioxide is created in the region of silicon dioxide.
Claim 15
Dependent Claim
18 words
In a method as in claim 11 wherein the conductive reduced species is insoluable in the etching solution.
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) | 1987-06-12 | 1987-12-12 | 1988-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-12 | 1991-12-12 | 1992-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-12 | 1995-12-12 | 1996-06-12 | $7700.00 | Window Closed / Lapsed |