Patent JPS5627933A successfully refreshed from Google Patents.
US6008137A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pattern formation of silicon nitride
Assignee: Vanguard International Semiconductor Corp
•
Filing: 1999-03-12
•
Granted: 1999-12-28
•
Expires: 2019-03-12
Abstract
Abstract A plasma etch method for forming a patterned silicon nitride layer within an integrated circuit. There is first provided a substrate having formed thereover a blanket silicon nitride layer. There is then formed upon the blanket silicon nitride layer a patterned photoresist layer. Finally, there is etched through a plasma etch method while employing the patterned photoresist layer as an etch mask layer the blanket silicon nitride layer to form a patterned silicon nitride layer. The plasma etch method employs an etchant gas composition comprising a perfluorocarbon etchant gas, a hydrofluorocarbon etchant gas and an oxygen etchant gas at a perfluorocarbon etchant gas flow rate, a hydrofluorocarbon etchant gas flow rate and an oxygen etchant gas flow rate which yields substantially no plasma etch bias of the patterned silicon nitride layer with respect to the patterned photoresist layer. When the patterned silicon nitride layer is employed within a thermal oxidation mask, the blanket silicon nitride layer is only nearly completely patterned through the plasma etch method. The nearly completely patterned silicon nitride layer is then completely patterned and over-etched through a second plasma etch method, where the second plasma etch method employs a second etchant gas composition comprising a perfluorocarbon etchant gas, a hydrofluorocarbon etchant gas and an oxygen etchant gas at a perfluorocarbon etchant gas flow rate, a hydrofluorocarbon etchant gas flow rate and an oxygen etchant gas flow rate which minimizes etching of a blanket silicon oxide layer formed beneath the patterned silicon nitride layer within the thermal oxidation mask.
Inventors
- 👤 Ching-Ying Lee
- 👤 Kuo-Chang Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:21
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
281 words
A method for forming field oxide (FOX) isolation regions within and upon a semiconductor substrate comprising: providing a semiconductor substrate; forming upon the semiconductor substrate a blanket silicon oxide layer; forming upon the blanket silicon oxide layer a blanket silicon nitride layer; forming upon the blanket silicon nitride layer a patterned photoresist layer; etching through a first plasma etch method while employing the patterned photoresist layer as an etch mask layer the blanket silicon nitride layer to form a nearly completely patterned silicon nitride layer, the first plasma etch method employing a first etchant gas composition comprising a perfluorocarbon etchant gas, a hydrofluorocarbon etchant gas and an oxygen etchant gas at a perfluorocarbon etchant gas flow rate, a hydrofluorocarbon etchant gas flow rate and an oxygen etchant gas flow rate which yields substantially no plasma etch bias of the nearly completely patterned silicon nitride layer with respect to the patterned photoresist layer; completely etching and over-etching through a second plasma etch method while employing the patterned photoresist layer as an etch mask layer the nearly completely patterned silicon nitride layer to form a patterned silicon nitride layer, the second plasma etch method employing a second etchant gas composition comprising a perfluorocarbon etchant gas, a hydrofluorocarbon etchant gas and an oxygen etchant gas at a perfluorocarbon etchant gas flow rate, a hydrofluorocarbon etchant gas flow rate and an oxygen etchant gas flow rate which minimizes etching of the blanket silicon oxide layer; and thermally oxidizing the semiconductor substrate while employing the patterned silicon nitride layer as a thermal oxidation mask to form through a local oxidation of silicon (LOCOS) method a field oxide (FOX) isolation region within and upon the semiconductor substrate.
Claim 2
Independent Claim
281 words
A method for forming field oxide (FOX) isolation regions within and upon a semiconductor substrate comprising: providing a semiconductor substrate; forming upon the semiconductor substrate a blanket silicon oxide layer; forming upon the blanket silicon oxide layer a blanket silicon nitride layer; forming upon the blanket silicon nitride layer a patterned photoresist layer; etching through a first plasma etch method while employing the patterned photoresist layer as an etch mask layer the blanket silicon nitride layer to form a nearly completely patterned silicon nitride layer, the first plasma etch method employing a first etchant gas composition comprising a perfluorocarbon etchant gas, a hydrofluorocarbon etchant gas and an oxygen etchant gas at a perfluorocarbon etchant gas flow rate, a hydrofluorocarbon etchant gas flow rate and an oxygen etchant gas flow rate which yields substantially no plasma etch bias of the nearly completely patterned silicon nitride layer with respect to the patterned photoresist layer; completely etching and over-etching through a second plasma etch method while employing the patterned photoresist layer as an etch mask layer the nearly completely patterned silicon nitride layer to form a patterned silicon nitride layer, the second plasma etch method employing a second etchant gas composition comprising a perfluorocarbon etchant gas, a hydrofluorocarbon etchant gas and an oxygen etchant gas at a perfluorocarbon etchant gas flow rate, a hydrofluorocarbon etchant gas flow rate and an oxygen etchant gas flow rate which minimizes etching of the blanket silicon oxide layer; and thermally oxidizing the semiconductor substrate while employing the patterned silicon nitride layer as a thermal oxidation mask to form through a local oxidation of silicon (LOCOS) method a field oxide (FOX) isolation region within and upon the semiconductor substrate.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein the blanket silicon oxide layer is from about 200 to about 350 angstroms thick.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein the blanket silicon nitride layer is from about 1000 to about 2000 angstroms thick.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein the patterned photoresist layer has linewidth and pitch dimensions of less than about 0.5 microns.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein the perfluorocarbon gas is carbon tetrafluoride and the hydrofluorocarbon gas is trifluoromethane.
Claim 7
Dependent Claim
46 words
The method of claim 1 further comprising maintaining constant the temperature of a substrate electrode when etching the blanket silicon nitride layer through the first plasma etch method and completely etching and over-etching the nearly completely patterned silicon nitride layer through the second plasma etch method.
Claim 8
Dependent Claim
25 words
The method of claim 6 wherein the temperature is maintained constant at a temperature in the range of about zero to about 30 degrees centigrade.
Claim 9
Dependent Claim
135 words
The method of claim 5 wherein: within the first plasma etch method the perfluorocarbon etchant gas flow rate is from about 10 to about 50 standard cubic centimeters per minute (sccm), the hydrofluorocarbon etchant gas flow rate is from about 10 to about 50 standard cubic centimeters per minute (sccm) and the oxygen etchant gas flow rate is from about 1 to about 30 standard cubic centimeters per minute (sccm); and within the second plasma etch method the perfluorocarbon etchant gas flow rate is from about 10 to about 50 standard cubic centimeters per minute (sccm), the hydrofluorocarbon etchant gas flow rate is from about 10 to about 50 standard cubic centimeters per minute (sccm) and the oxygen etchant gas flow rate is from about 30 to about 70 standard cubic centimeters per minute (sccm).
Claim 10
Dependent Claim
135 words
The method of claim 5 wherein: within the first plasma etch method the perfluorocarbon etchant gas flow rate is from about 10 to about 50 standard cubic centimeters per minute (sccm), the hydrofluorocarbon etchant gas flow rate is from about 20 to about 30 standard cubic centimeters per minute (sccm) and the oxygen etchant gas flow rate is from about 6 to about 15 standard cubic centimeters per minute (sccm); and within the second plasma etch method the perfluorocarbon etchant gas flow rate is from about 10 to about 50 standard cubic centimeters per minute (sccm), the hydrofluorocarbon etchant gas flow rate is from about 15 to about 25 standard cubic centimeters per minute (sccm) and the oxygen etchant gas flow rate is from about 40 to about 60 standard cubic centimeters per minute (sccm).
References Cited (Backward Citations)
US30505A
Cited
USRE30505E
Cited
US4174251A
Cited
US4180432A
Cited
US4374698A
Cited
US4529476A
Cited
US4484979A
Cited
US4654114A
Cited
US4793897A
Cited
US4857140A
Cited
US5431772A
Cited
US5858877A
Cited
US5432117A
Cited
US5670017A
Cited
US5644153A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-12-27 | 2003-06-28 | 2003-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-12-27 | 2007-06-28 | 2007-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-12-27 | 2011-06-28 | 2011-12-28 | $7700.00 | Window Closed / Lapsed |