Patent US5384281A successfully refreshed from Google Patents.
US5384281A
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US
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Non-conformal and oxidizable etch stops for submicron features
Assignee: International Business Machines Corp
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Filing: 1992-12-29
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Granted: 1995-01-24
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Expires: 2012-12-29
Abstract
Abstract A process for etching narrow features, particularly submicron borderless contacts, in a semiconductor substrate is disclosed. The process comprises depositing, by an orientation-sensitive technique, film which will act as an etch stop. The film is significantly thicker on horizontal surfaces than on vertical. A second layer is deposited and then etched using the first film as an etch stop. In one embodiment the etch stop is composed of an oxidizable material.
Inventors
- 👤 Donald M. Kenney
- 👤 Stephen E. Luce
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:55
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/074; H10W20/076; H10W20/031; H10W20/069; H10W20/075; H10W20/093; H10W20/096; H10W20/097; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/947; Y10S438/97
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
101 words
A process for etching narrow features in a semiconductor substrate comprising the steps of: (a) depositing, by an orientation-sensitive deposition technique, a first film in a plurality of cavities in a semiconductor substrate, whereby said first film is deposited preferentially on surfaces parallel to a long axis of said semiconductor substrate; (b) depositing a second film over said first film, said second film comprising a material that can be selectively etched in the presence of said first film; (c) directionally etching said second film using said first film as an etch stop; and (d) removing said first film from said cavities.
Claim 2
Dependent Claim
101 words
A process for etching narrow features in a semiconductor substrate comprising the steps of: (a) depositing, by an orientation-sensitive deposition technique, a first film in a plurality of cavities in a semiconductor substrate, whereby said first film is deposited preferentially on surfaces parallel to a long axis of said semiconductor substrate; (b) depositing a second film over said first film, said second film comprising a material that can be selectively etched in the presence of said first film; (c) directionally etching said second film using said first film as an etch stop; and (d) removing said first film from said cavities.
Claim 3
Dependent Claim
37 words
A process according to claim 1 wherein said first film is deposited on surfaces perpendicular to a long axis to a thickness which is less than one-half the thickness deposited on surfaces parallel to a long axis.
Claim 4
Dependent Claim
15 words
A process according to claim 1 wherein said first film is deposited by collimated sputtering.
Claim 5
Dependent Claim
109 words
A process for etching narrow features in a semiconductor substrate comprising the steps of: (a) depositing, by an orientation-sensitive deposition technique, a first film in a plurality of cavities in a semiconductor substrate, whereby said first film is deposited preferentially on surfaces parallel to a long axis of said semiconductor substrate; (b) depositing a second film over said first film, said second film comprising a material that can be selectively etched in the presence of said first film; and (c) directionally etching said second film using said first film as an etch stop wherein said first film is chosen from the group consisting of amorphous silicon and polycrystalline silicon.
Claim 6
Dependent Claim
109 words
A process for etching narrow features in a semiconductor substrate comprising the steps of: (a) depositing, by an orientation-sensitive deposition technique, a first film in a plurality of cavities in a semiconductor substrate, whereby said first film is deposited preferentially on surfaces parallel to a long axis of said semiconductor substrate; (b) depositing a second film over said first film, said second film comprising a material that can be selectively etched in the presence of said first film; and (c) directionally etching said second film using said first film as an etch stop wherein said first film is chosen from the group consisting of amorphous silicon and polycrystalline silicon.
Claim 7
Dependent Claim
15 words
A process according to claim 4 wherein said second film is boron phosphorus silicate glass.
Claim 8
Dependent Claim
20 words
A process according to claim 5 wherein said second film is RIE etched using 5% oxygen in CF 4 .
Claim 9
Dependent Claim
100 words
A process for etching narrow features in a semiconductor substrate comprising the steps of: (a) depositing, by an orientation-sensitive deposition technique, a first film in a plurality of cavities in a semiconductor substrate, whereby said first film is deposited preferentially on surfaces parallel to a long axis of said semiconductor substrate; (b) depositing a second film over said first film, said second film comprising a material that can be selectively etched in the presence of said first film; and (c) directionally etching said second film using said first film as an etch stop, wherein said first film is silicon nitride.
Claim 10
Dependent Claim
100 words
A process for etching narrow features in a semiconductor substrate comprising the steps of: (a) depositing, by an orientation-sensitive deposition technique, a first film in a plurality of cavities in a semiconductor substrate, whereby said first film is deposited preferentially on surfaces parallel to a long axis of said semiconductor substrate; (b) depositing a second film over said first film, said second film comprising a material that can be selectively etched in the presence of said first film; and (c) directionally etching said second film using said first film as an etch stop, wherein said first film is silicon nitride.
Claim 11
Dependent Claim
113 words
A process for etching narrow features in a semiconductor substrate comprising the steps of: (a) depositing, by an orientation-sensitive deposition technique, an oxidizable first film on at least a portion of a semiconductor substrate, said portion of said semiconductor substrate having a non-oxidizable surface, whereby said oxidizable film is deposited preferentially on surfaces parallel to a long axis of said semiconductor substrate; (b) depositing a second film over said first film, said second film comprising a material which can be selectively etched in the presence of said first film; (c) patterning said second film with a plurality of openings extending to said first film; and (d) removing said first film in said openings.
Claim 12
Dependent Claim
113 words
A process for etching narrow features in a semiconductor substrate comprising the steps of: (a) depositing, by an orientation-sensitive deposition technique, an oxidizable first film on at least a portion of a semiconductor substrate, said portion of said semiconductor substrate having a non-oxidizable surface, whereby said oxidizable film is deposited preferentially on surfaces parallel to a long axis of said semiconductor substrate; (b) depositing a second film over said first film, said second film comprising a material which can be selectively etched in the presence of said first film; (c) patterning said second film with a plurality of openings extending to said first film; and (d) removing said first film in said openings.
Claim 13
Dependent Claim
19 words
A process according to claim 8 further comprising a step of oxidizing said first film under said second film.
Claim 14
Dependent Claim
35 words
A process according to claim 8 wherein said oxidizable first film is deposited on surfaces perpendicular to said long axis to a thickness which is less than half the thickness parallel to said long axis.
Claim 15
Dependent Claim
25 words
A process according to claim 8 wherein said orientation-sensitive deposition method is selected from the group consisting of collimated sputtering, evaporation and electron-cyclotron resonance deposition.
Claim 16
Dependent Claim
13 words
A process according to claim 11 wherein said deposition method is collimated sputtering.
Claim 17
Dependent Claim
22 words
A process according to claim 8 wherein said first film is selected from the group consisting of amorphous silicon and polycrystalline silicon.
Claim 18
Dependent Claim
15 words
A process according to claim 8 wherein said second film is boron phosphorus silicate glass.
Claim 19
Dependent Claim
17 words
A process according to claim 8 wherein said narrow feature is a window for a borderless contact.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-01-23 | 1998-07-25 | 1999-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-23 | 2002-07-25 | 2003-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-23 | 2006-07-25 | 2007-01-24 | $7700.00 | Window Closed / Lapsed |