Patent US5453395A successfully refreshed from Google Patents.
US5453395A
Expired / Lapsed
US
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Isolation technology using liquid phase deposition
Assignee: United Microelectronics Corp
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Filing: 1994-03-21
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Granted: 1995-09-26
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Expires: 2014-03-21
Abstract
Abstract A method of forming an isolation structure on a silicon substrate using liquid phase deposition which is capable of selectively depositing oxide only in trenches of the substrate, to grow recessed field oxides of same height, and leave a flat surface of the substrate. The liquid phase deposition is performed using saturated hydrofluosilicic acid as a reactant.
Inventors
- 👤 Water Lur
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:15
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/10; H10W10/17; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6326; H10P14/6342; H10W10/01; H10W10/011; H10W10/014; H10W10/0143
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
168 words
A method of forming an isolation structure on a silicon substrate, comprising the following steps: (a) forming at least one trench in said silicon substrate, the trench having trench sidewalls and a trench bottom; (b) forming a first oxide layer on a surface of said silicon substrate and on the trench sidewalls and the trench bottom; (c) adhering a protective layer on the first oxide layer; (d) coating and patterning a photoresist on the protective layer to expose the trench; (e) removing the protective layer on the trench bottom by etching using the photoresist as a mask; (f) forming a second oxide layer in the trench using liquid phase deposition; (h) removing the photoresist; (g) removing the protective layer to thereby form gaps between the first oxide layer on the trench sidewalls and the second oxide layer; (h) forming a dielectric layer to fill the gaps using deposition and etching back the dielectric layer; and (i) removing the first oxide layer on the surface of the silicon substrate.
Claim 2
Independent Claim
168 words
A method of forming an isolation structure on a silicon substrate, comprising the following steps: (a) forming at least one trench in said silicon substrate, the trench having trench sidewalls and a trench bottom; (b) forming a first oxide layer on a surface of said silicon substrate and on the trench sidewalls and the trench bottom; (c) adhering a protective layer on the first oxide layer; (d) coating and patterning a photoresist on the protective layer to expose the trench; (e) removing the protective layer on the trench bottom by etching using the photoresist as a mask; (f) forming a second oxide layer in the trench using liquid phase deposition; (h) removing the photoresist; (g) removing the protective layer to thereby form gaps between the first oxide layer on the trench sidewalls and the second oxide layer; (h) forming a dielectric layer to fill the gaps using deposition and etching back the dielectric layer; and (i) removing the first oxide layer on the surface of the silicon substrate.
Claim 3
Dependent Claim
43 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 1, wherein said protective layer is formed by first forming an adhesive layer on said first oxide layer and then forming a tungsten layer on said adhesive layer.
Claim 4
Dependent Claim
23 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 2, wherein said adhesive layer is titanium nitride.
Claim 5
Dependent Claim
24 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 2, wherein said adhesive layer is a titanium-tungsten alloy.
Claim 6
Dependent Claim
28 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 1 further including the step of densifying the second oxide layer by heating.
Claim 7
Dependent Claim
33 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 1, further including a step of implanting impurities into said substrate to form a channel stop implantation layer.
Claim 8
Dependent Claim
31 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 1, wherein the thickness of the first oxide layer is between 50 Å to 200 Å.
Claim 9
Dependent Claim
30 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 2, wherein the thickness of the adhesive layer is between 100 Å to 500 Å.
Claim 10
Dependent Claim
30 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 2, wherein the thickness of the tungsten layer is between 500 Å to 2000 Å.
Claim 11
Dependent Claim
30 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 2, wherein the step coverage ratio of the tungsten layer is between 40% to 95%.
Claim 12
Dependent Claim
34 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 1, wherein the critical dimension bias is between 0 to -0.1 μm when patterning the photoresist in step (d).
Claim 13
Dependent Claim
36 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 1, wherein the liquid phase deposition is performed at 33° C. to 37° C. using saturated hydrofluosilicic acid as a reactant.
Claim 14
Dependent Claim
23 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 1, wherein the dielectric layer is silicon dioxide.
Claim 15
Dependent Claim
23 words
The method of forming an isolation structure on a silicon substrate as claimed in claim 1, wherein the dielectric layer is silicon nitride.
Claim 16
Independent Claim
100 words
A method of forming an isolation structure on a semiconductor substrate, said method comprising the steps of: (a) forming at least one trench in said semiconductor substrate, the trench having trench sidewalls and a trench bottom; (b) forming an oxide layer on at least the trench bottom; (c) forming a protective layer on said semiconductor substrate and in said at least one trench, said protective layer being provided with an aperture therein over said trench bottom; and (d) forming a field oxide layer on said oxide layer in said at least one trench by liquid phase deposition of field oxide.
Claim 17
Independent Claim
100 words
A method of forming an isolation structure on a semiconductor substrate, said method comprising the steps of: (a) forming at least one trench in said semiconductor substrate, the trench having trench sidewalls and a trench bottom; (b) forming an oxide layer on at least the trench bottom; (c) forming a protective layer on said semiconductor substrate and in said at least one trench, said protective layer being provided with an aperture therein over said trench bottom; and (d) forming a field oxide layer on said oxide layer in said at least one trench by liquid phase deposition of field oxide.
Claim 18
Dependent Claim
47 words
The method of forming an isolation structure on a semiconductor substrate as claimed in claim 15, further including the steps of: (e) removing the protective layer and thereby leaving gaps along the trench sidewalls; and (f) filling said gaps along the trench sidewalls with a dielectric material.
Claim 19
Dependent Claim
41 words
The method of forming an isolation structure on a semiconductor substrate as claimed in claim 16, further including the step of: (g) etching away exposed portions of said oxide layer and said dielectric material to form a generally planar flat structure.
Claim 20
Dependent Claim
57 words
The method of forming an isolation structure on a semiconductor substrate as claimed in claim 16, wherein said protective layer is formed by forming an adhesive layer over said substrate, forming a tungsten layer over said adhesive layer and patterning to remove those portions of the adhesive layer and the tungsten layer which cover the trench bottom.
References Cited (Backward Citations)
JPS59208729A
Cited
JPS63142831A
Cited
JPH04106954A
Cited
JPH04132240A
Cited
JPH04245662A
Cited
US5256593A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-09-25 | 1999-03-27 | 1999-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-25 | 2003-03-27 | 2003-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-25 | 2007-03-27 | 2007-09-26 | $7700.00 | Window Closed / Lapsed |