Patent US4721687A successfully refreshed from Google Patents.
US4721687A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of increasing the thickness of a field oxide
Assignee: Toshiba Corp
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Filing: 1987-02-06
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Granted: 1988-01-26
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Expires: 2007-02-06
Abstract
Abstract A method of manufacturing a semiconductor substrate, and, in particular, a technique of electrically isolating a semiconductor element formed on a semiconductor substrate. The method comprises the steps of depositing a silicon oxide layer on the surface of a silicon substrate, for its protection; forming a silicon nitride layer on the silicon oxide layer; selectively eliminating the silicon nitride layer; oxidizing the silicon substrate, with the retained silicon nitride layer being used as a mask, thereby providing an oxide layer; depositing a polycrystalline silicon layer on the oxide layer and the retained acid-resisting layer; oxidizing the polycrystalline silicon layer to provide an insulation layer; eliminating the insulation layer until the silicon nitride layer is exposed; and removing all the silicon nitride layer. The method is capable of enabling the formation of a thick semiconductor element-isolating oxide layer, with a high precision, in a narrow region from which the semiconductor element is to be isolated.
Inventors
- 👤 Masakazu Kakumu
- 👤 Sigeru Morita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:35
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0125; H10W10/10; H10W10/13; Y; Y10; Y10S; Y10S148/00; Y10S148/117
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
94 words
A method of manufacturing a semiconductor device, which comprises the steps of: depositing a surface-protecting layer on a semiconductor substrate; forming an acid-resisting layer on said surface-protecting layer; selectively eliminating said acid-resisting layer; oxidizing said semiconductor substrate, with the retained acid-resisting layer being used as a mask, thereby to provide an oxidized layer; depositing a silicon layer on said oxidized layer and said retained acid-resisting layer; oxidizing the silicon layer to provide an insulation layer; eliminating said oxidized silicon layer until said retained acid-resisting layer is exposed; and eliminating all the retained acid-resisting layer.
Claim 2
Independent Claim
94 words
A method of manufacturing a semiconductor device, which comprises the steps of: depositing a surface-protecting layer on a semiconductor substrate; forming an acid-resisting layer on said surface-protecting layer; selectively eliminating said acid-resisting layer; oxidizing said semiconductor substrate, with the retained acid-resisting layer being used as a mask, thereby to provide an oxidized layer; depositing a silicon layer on said oxidized layer and said retained acid-resisting layer; oxidizing the silicon layer to provide an insulation layer; eliminating said oxidized silicon layer until said retained acid-resisting layer is exposed; and eliminating all the retained acid-resisting layer.
Claim 3
Dependent Claim
17 words
The method according to claim 1, wherein said surface-protecting layer is prepared from a silicon oxide layer.
Claim 4
Dependent Claim
18 words
The method according to claim 1, wherein said surface-protecting layer is deposited by the vapor phase growth method.
Claim 5
Dependent Claim
17 words
The method according to claim 1, wherein said acid-resisting layer is prepared from a silicon nitride layer.
Claim 6
Dependent Claim
15 words
The method according to claim 1, wherein said semiconductor substrate consists of a silicon substrate.
Claim 7
Dependent Claim
27 words
The method according to claim 1, wherein said semiconductor substrate is oxidized in an atmosphere of H 2 +O 2 held at a temperature of 1000° C.
Claim 8
Dependent Claim
19 words
The method according to claim 1, wherein said polycrystalline silicon layer is formed by the vapor phase growth method.
Claim 9
Dependent Claim
30 words
The method according to claim 1, wherein said polycrystalline silicon layer is prepared by oxidation in an atmosphere of H 2 +O 2 held at a temperature of 1000° C.
Claim 10
Dependent Claim
22 words
The method according to claim 1, wherein said oxidized polycrystalline silicon layer is removed by immersion in a solution of ammonium fluoride.
Claim 11
Dependent Claim
20 words
The method according to claim 1, wherein said acid-resisting layer is eliminated by use of the chemical dry etching process.
Claim 12
Independent Claim
98 words
A method of manufacturing a semiconductor apparatus which comprises the steps of: forming a surface-protecting layer on a semiconductor substrate; depositing an acid-resisting layer on said surface-protecting layer; selectively eliminating said acid-resisting layer; oxidizing said semiconductor substrate by oxidation, with the retained acid-resisting layer used as a mask, thereby providing an oxidized layer; depositing a silicon layer on said oxidized layer and said retained acid-resisting layer; eliminating said silicon layer until said retained acid-resisting layer is exposed; oxidizing the silicon layer retained on said oxidized layer to provide an insulation layer; and removing all the retained acid-resisting layer.
Claim 13
Independent Claim
98 words
A method of manufacturing a semiconductor apparatus which comprises the steps of: forming a surface-protecting layer on a semiconductor substrate; depositing an acid-resisting layer on said surface-protecting layer; selectively eliminating said acid-resisting layer; oxidizing said semiconductor substrate by oxidation, with the retained acid-resisting layer used as a mask, thereby providing an oxidized layer; depositing a silicon layer on said oxidized layer and said retained acid-resisting layer; eliminating said silicon layer until said retained acid-resisting layer is exposed; oxidizing the silicon layer retained on said oxidized layer to provide an insulation layer; and removing all the retained acid-resisting layer.
Claim 14
Dependent Claim
16 words
The method according to claim 11, wherein said surface-protecting layer consists of a silicon oxide layer.
Claim 15
Dependent Claim
18 words
The method according to claim 11, wherein said surface-protecting layer is deposited by the vapor phase growth method.
Claim 16
Dependent Claim
16 words
The method according to claim 11, wherein said acid-resisting layer consists of a silicon nitride layer.
Claim 17
Dependent Claim
15 words
The method according to claim 11, wherein said semiconductor substrate consists of a silicon substrate.
Claim 18
Dependent Claim
27 words
The method according to claim 11, wherein said semiconductor substrate is oxidized in an atmosphere of H 2 +O 2 held at a temperature of 1000° C.
Claim 19
Dependent Claim
28 words
The method according to claim 11, wherein said polycrystalline silicon layer is oxidized in an atmosphere of H 2 +O 2 held at a temperature of 1000° C.
Claim 20
Dependent Claim
22 words
The method according to claim 11, wherein said oxidized polycrystalline silicon layer is eliminated by immersion in a solution of ammonium fluoride.
Claim 21
Dependent Claim
20 words
The method according to claim 11, wherein said acid-resisting layer is eliminated by use of the chemical dry etching process.
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) | 1991-01-25 | 1991-07-27 | 1992-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-25 | 1995-07-27 | 1996-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-25 | 1999-07-27 | 2000-01-26 | $7700.00 | Window Closed / Lapsed |