Patent US6020091A successfully refreshed from Google Patents.
US6020091A
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Hard etch mask
Assignee: Polaris Innovations Ltd
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Filing: 1997-09-30
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Granted: 2000-02-01
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Expires: 2017-09-30
Abstract
Abstract A hard etch mask comprising phosphorus doped silicate glass for reactive ion etching of a substrate to form trenches therein.
Inventors
- 👤 Gill Yong Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:29
CPC Classifications
H; H10; H10P; H10P76/00; H10P76/40; H10P76/405; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/038; H10B12/0387; H10P50/00; H10P50/69; H10P50/691; H10P50/692
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
57 words
A pad stack for etching a substrate comprising: a pad oxide layer formed on the substrate; a pad stop layer formed on the pad oxide layer; and a PSG hard mask layer formed on the pad stop layer, the PSG hard mask layer for providing an etch mask for a reactive ion etch for forming deep trenches.
Claim 2
Dependent Claim
57 words
A pad stack for etching a substrate comprising: a pad oxide layer formed on the substrate; a pad stop layer formed on the pad oxide layer; and a PSG hard mask layer formed on the pad stop layer, the PSG hard mask layer for providing an etch mask for a reactive ion etch for forming deep trenches.
Claim 3
Dependent Claim
23 words
The pad stack as recited in claim 1, wherein the PSG layer is from about 3,000 Å to about 20,000 Å in thickness.
Claim 4
Dependent Claim
23 words
The pad stack as recited in claim 1, wherein the PSG layer is from about 5,000 Å to about 9,000 Å in thickness.
Claim 5
Dependent Claim
39 words
The pad stack as recited in claim 1, wherein the PSG layer includes a phosphorous concentration such that the PSG layer is selectively etched relative to the pad oxide layer and below a concentration which forms phosphoric acid crystals.
Claim 6
Dependent Claim
35 words
The pad stack as recited in claim 4, wherein the PSG layer is selectively etched relative to the pad oxide layer at a ratio of between about 50 to 1 to about 500 to 1.
Claim 7
Dependent Claim
24 words
The pad stack as recited in claim 1, wherein the PSG layer includes a phosphorous concentration between about 1% to about 11% by weight.
Claim 8
Independent Claim
58 words
A method of forming deep trenches in a substrate comprising the steps of: providing a pad stack having a PSG hard mask layer; patterning the hard mask layer to identify locations for deep trenches; and reactive ion etching the substrate ai the identified locations wherein the hard mask layer provides an etch mask for the reactive ion etching.
Claim 9
Independent Claim
58 words
A method of forming deep trenches in a substrate comprising the steps of: providing a pad stack having a PSG hard mask layer; patterning the hard mask layer to identify locations for deep trenches; and reactive ion etching the substrate ai the identified locations wherein the hard mask layer provides an etch mask for the reactive ion etching.
Claim 10
Dependent Claim
40 words
The method as recited in claim 7, wherein the step of patterning includes the steps of: forming a resist on the hard mask layer; and developing the resist to form unprotected regions at the identified locations for the deep trenches.
Claim 11
Dependent Claim
28 words
The method as recited in claim 8, further comprises the step of depositing an anti-reflection coating on the pad stack prior to forming the resist to improve resolution.
Claim 12
Dependent Claim
30 words
The method as recited in claim 9, further comprises the step of depositing a barrier layer on the pad stack prior to forming the resist and depositing the anti-reflection coating.
Claim 13
Dependent Claim
44 words
The method as recited in claim 10, further comprises the steps of: reactive ion etching the pad stack to expose the substrate; exposing the hard mask; and reactive ion etching the substrate using the hard mask layer as a mask to form deep trenches.
Claim 14
Dependent Claim
36 words
The method as recited in claim 7, wherein the pad stack further comprises a pad oxide layer and includes the step of removing the hard mask layer by selective etching relative to the pad oxide layer.
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) | 2003-01-31 | 2003-08-02 | 2004-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-01-31 | 2007-08-02 | 2008-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-01-31 | 2011-08-02 | 2012-02-01 | $7700.00 | Window Closed / Lapsed |