US5358891A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Trench isolation with planar topography and method of fabrication
Assignee: Intel Corp
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Filing: 1993-06-29
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Granted: 1994-10-25
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Expires: 2013-06-29
Abstract
Abstract A method of forming and refilling a trench in a substrate. First a trench is formed in the substrate. The trench is then refilled with a conformal material. Next, a recess is etched into the top portion of the refilled trench. The recess is then refilled with a second material until the refilled recess and substrate are substantially planar.
Inventors
- 👤 Chi-Hwa Tsang
- 👤 Kerry L. Spurgin
- 👤 Deborah A. Parsons
- 👤 William L. Hargrove
- 👤 Ganesan Radhakrishnan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:47
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0121; H10W10/041; H10W10/10; H10W10/13; H10W10/40; Y; Y10; Y10S; Y10S148/00; Y10S148/05
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
87 words
A method of forming a trench and refilling said trench in a substrate comprising the steps of: etching a trench in said substrate wherein said trench has a first depth and a first width; filling said trench with a conformal material; etching a recess into said refilled trench wherein said recess has a second depth and a second width wherein said second depth is less than said first depth; and growing a thermal oxide in said recess until said thermal oxide is substantially planar with said substrate.
Claim 2
Independent Claim
87 words
A method of forming a trench and refilling said trench in a substrate comprising the steps of: etching a trench in said substrate wherein said trench has a first depth and a first width; filling said trench with a conformal material; etching a recess into said refilled trench wherein said recess has a second depth and a second width wherein said second depth is less than said first depth; and growing a thermal oxide in said recess until said thermal oxide is substantially planar with said substrate.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein said second width is greater than said first width.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein said trench is substantially anisotropic etched by reactive ion etching with a chemistry comprising HBr.
Claim 5
Dependent Claim
31 words
The method of claim 1 wherein said etching of said recess is a substantially anisotropic etched by plasma etching with a chemistry comprising C 2 F 6 and O 2 .
Claim 6
Dependent Claim
31 words
The method of claim 1 further comprising the step of forming a trench oxide on the sides and in the bottom of said trench before the step of filling said trench.
Claim 7
Dependent Claim
27 words
The method of claim 5 wherein said conformal material is selected from the group consisting of polysilicon and amorphous silicon and is formed by chemical vapor deposition.
Claim 8
Independent Claim
206 words
A method of forming an isolation structure in a silicon substrate comprising the steps of: etching a trench having a first depth and first width into said substrate; forming a trench oxide layer on said substrate and on the sidewalls and on the bottom of said trench; forming a polysilicon layer on said trench oxide layer on said substrate and on said oxide layer on the sidewalls and on the bottom of said trench wherein said trench becomes filled; removing said polysilicon layer and said trench oxide layer from the surface of said substrate; forming a silicon nitride layer on said substrate and on said filled trench; forming and patterning a masking layer on said nitride layer to define a location over said filled trench where a recess will be formed; etching a recess at said location through said nitride layer, into said silicon substrate and said filled trench, wherein said recess is formed to a second depth and a second width, wherein said second depth is less than said first depth and said second width is greater than said first width; and forming a field oxide layer in said recess such that said field oxide layer in said recess is substantially planar with said substrate.
Claim 9
Independent Claim
206 words
A method of forming an isolation structure in a silicon substrate comprising the steps of: etching a trench having a first depth and first width into said substrate; forming a trench oxide layer on said substrate and on the sidewalls and on the bottom of said trench; forming a polysilicon layer on said trench oxide layer on said substrate and on said oxide layer on the sidewalls and on the bottom of said trench wherein said trench becomes filled; removing said polysilicon layer and said trench oxide layer from the surface of said substrate; forming a silicon nitride layer on said substrate and on said filled trench; forming and patterning a masking layer on said nitride layer to define a location over said filled trench where a recess will be formed; etching a recess at said location through said nitride layer, into said silicon substrate and said filled trench, wherein said recess is formed to a second depth and a second width, wherein said second depth is less than said first depth and said second width is greater than said first width; and forming a field oxide layer in said recess such that said field oxide layer in said recess is substantially planar with said substrate.
Claim 10
Dependent Claim
26 words
The method of claim 7 further comprising the step of forming a pad oxide layer on said silicon substrate prior to forming said silicon nitride layer.
Claim 11
Dependent Claim
21 words
The method of claim 7 further comprising the step of removing said patterned nitride layer after forming said field oxide layer.
Claim 12
Dependent Claim
28 words
The method of claim 7 further comprising the step of forming a channel stop region in the bottom of said trench after the step of etching said trench.
Claim 13
Dependent Claim
21 words
The method of claim 7 wherein said trench is substantially anisotropically etched by reactive ion etching with a plasma comprising HBr.
Claim 14
Dependent Claim
28 words
The method of claim 7 wherein said recess is substantially anisotropically etched by reactive ion etching with a chemistry comprising C 2 F 6 and O 2 .
Claim 15
Dependent Claim
14 words
The method of claim 7 wherein said trench oxide is grown utilizing chlorine chemistry.
Claim 16
Dependent Claim
20 words
The method of claim 13 wherein said trench oxide is grown to a thickness in the range of 200-600 Å.
Claim 17
Dependent Claim
23 words
The method of claim 7 wherein said second depth is a depth sufficient to remove any nitride residue remaining from said nitride layer.
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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) | 1997-10-24 | 1998-04-25 | 1998-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-24 | 2002-04-25 | 2002-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-24 | 2006-04-25 | 2006-10-25 | $7700.00 | Window Closed / Lapsed |