Patent US4855258A successfully refreshed from Google Patents.
US4855258A
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US
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Native oxide reduction for sealing nitride deposition
Assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
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Filing: 1987-10-22
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Granted: 1989-08-08
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Expires: 2007-10-22
Abstract
Abstract A process for forming a thin sealing layer of silicon nitride directly upon a silicon substrate to minimize bird's beak encroachment. The process employs in situ fabrication whereby the native oxide is removed from the silicon substrate by etching the hydrogen or hydrogen chloride and followed in direct succession, and in the absence of exposure to an oxidizing environment, with the deposition of a silicon nitride layer by LPCVD. Bird's beak encroachment is incrementally reduced by the absence of the native oxide layer as a path for oxygen species movement during the field oxide growth.
Inventors
- 👤 Derryl D. J. Allman
- 👤 Steven S. Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:18
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/69; H10P14/694; H10P14/6943; H10P14/69433; H10P14/61; H10P14/65; H10P14/6502; H10P14/6512; H10P14/66; H10P14/668; H10P14/6681; H10P14/6682; H10P70/00; H10P70/10; H10P70/12; H10P14/63; H10P14/6326; H10P14/6328; H10P14/6334; H10P14/692; H10P14/6921; H10P14/69215; Y; Y10; Y10S; Y10S148/00; Y10S148/081; Y10S148/114; Y10S148/118; Y10S438/00; Y10S438/906
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
126 words
A semiconductor fabrication process for depositing a sealing layer useable during field oxide growth on a silicon substrate surface, comprising the steps of: conditioning the substrate in a chamber at reduced pressure and elevated temperature; removing the native silicon dioxide from the silicon substrate by initiating a flow of silicon dioxide etchant gas through the chamber while maintaining a first subatmospheric pressure and an elevated temperature; purging the chamber of etching or oxidizing gases by evacuation; initiating the flow of silicon nitride deposition gases to fill the chamber and raise the pressure to a second subatmospheric level, while maintaining an elevated temperature; and depositing directly upon the silicon substrate a sealed interface masking layer of silicon nitride nominally ranging from ten to twenty nanometers in thickness.
Claim 2
Dependent Claim
126 words
A semiconductor fabrication process for depositing a sealing layer useable during field oxide growth on a silicon substrate surface, comprising the steps of: conditioning the substrate in a chamber at reduced pressure and elevated temperature; removing the native silicon dioxide from the silicon substrate by initiating a flow of silicon dioxide etchant gas through the chamber while maintaining a first subatmospheric pressure and an elevated temperature; purging the chamber of etching or oxidizing gases by evacuation; initiating the flow of silicon nitride deposition gases to fill the chamber and raise the pressure to a second subatmospheric level, while maintaining an elevated temperature; and depositing directly upon the silicon substrate a sealed interface masking layer of silicon nitride nominally ranging from ten to twenty nanometers in thickness.
Claim 3
Dependent Claim
38 words
The process recited in claim 1, wherein the silicon dioxide etchant gas includes HCl, the first pressure in the chamber is in the range of 100 mTorr, and the elevated temperature is in the range of 800°-900° C.
Claim 4
Dependent Claim
32 words
The process recited in claim 2, wherein the silicon nitride deposition gases include silane or dichlorosilane and ammonia, and the second pressure in the chamber is in the range of 700 mTorr.
Claim 5
Dependent Claim
41 words
The process recited in claim 1, wherein the silicon dioxide etchant gas includes H 2 , the first pressure in the chamber is in the range of 100 mTorr, and the elevated temperature is in the range of a 800°-900° C.
Claim 6
Dependent Claim
32 words
The process recited in claim 4, wherein the silicon nitride deposition gases include silane or dichlorosilane and ammonia, and the second pressure in the chamber is in the range of 700 mTorr.
Claim 7
Dependent Claim
86 words
A process for depositing a thin layer of silicon nitride directly onto a silicon substrate, comprising the steps of: etching the native silicon dioxide from the silicon substrate using an HCl gas mixture in a chamber maintained at a first subatmospheric pressure and an elevated temperature; purging the chamber of gas residuals by evacuation; and depositing silicon nitride onto the substrate using silane or dichlorosilane and ammonia in situ and immediately following evacuation while maintaining the chamber at a second subatmospheric pressure and an elevated temperature.
Claim 8
Dependent Claim
86 words
A process for depositing a thin layer of silicon nitride directly onto a silicon substrate, comprising the steps of: etching the native silicon dioxide from the silicon substrate using an HCl gas mixture in a chamber maintained at a first subatmospheric pressure and an elevated temperature; purging the chamber of gas residuals by evacuation; and depositing silicon nitride onto the substrate using silane or dichlorosilane and ammonia in situ and immediately following evacuation while maintaining the chamber at a second subatmospheric pressure and an elevated temperature.
Claim 9
Dependent Claim
29 words
The process recited in claim 6, wherein the first subatmospheric pressure is in the range of 100 mTorr and the elevated temperatures is in the range of 800°-900° C.
Claim 10
Dependent Claim
87 words
A process for depositing a thin layer of silicon nitride directly onto a silicon substrate, comprising the steps of: etching the native silicon dioxide from the silicon substrate using an H 2 gas mixture in a chamber maintained at a first subatmospheric pressure and an elevated temperature; purging the chamber of gas residuals by evacuation; and depositing silicon nitride onto the substrate using silane or dichlorosilane and ammonia in situ and immediately following evacuation while maintaining the chamber at a second subatmospheric pressure and an elevated temperature.
Claim 11
Dependent Claim
87 words
A process for depositing a thin layer of silicon nitride directly onto a silicon substrate, comprising the steps of: etching the native silicon dioxide from the silicon substrate using an H 2 gas mixture in a chamber maintained at a first subatmospheric pressure and an elevated temperature; purging the chamber of gas residuals by evacuation; and depositing silicon nitride onto the substrate using silane or dichlorosilane and ammonia in situ and immediately following evacuation while maintaining the chamber at a second subatmospheric pressure and an elevated temperature.
Claim 12
Dependent Claim
28 words
The process recited in claim 8, wherein the first subatmosphere pressure is in the range of 100 mTorr and the elevated temperatures in the range of 800°-900° C.
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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) | 1992-08-07 | 1993-02-06 | 1993-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-07 | 1997-02-06 | 1997-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-07 | 2001-02-06 | 2001-08-08 | $7700.00 | Window Closed / Lapsed |