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US5075251A
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Tungsten silicide self-aligned formation process
Assignee: L'ETAT FRANCAIS
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Filing: 1989-09-08
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Granted: 1991-12-24
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Expires: 2009-09-08
Abstract
Abstract A process for forming tungsten or molybdenum silicide on silicon apparent regions (6) of a silicon wafer surface (1) also comprising oxidized regions (2) includes the steps consisting in uniformly coating the wafer with a tungsten or molybdenum layer (10) and annealing at a temperature ranging from 700° C. to 1000° C. The annealing step is carried out in presence of a low pressure gas forming a chemical composite with tungsten or molybdenum. The composite is then selectively etched.
Inventors
- 👤 Joaquim Torres
- 👤 Jean Palleau
- 👤 Noureddine Bourhila
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:01
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01306; H10D64/01308; H10D64/0131; H10D64/011; H10D64/0111; H10D64/0112; Y; Y10; Y10S; Y10S148/00; Y10S148/019; Y10S148/147
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
139 words
A process of forming self-aligned metal silicide on silicon apparent regions of a silicon wafer surface having oxidized regions comprising: uniformly coating said surface of said wafer with a metal selected from the group consisting of tungsten and molybdenum; annealing said metal coating in the presence of a reactive gas having a partial pressure lower than 10 2 pascals and selected from the group consisting of oxygen, NH 3 , and mixtures thereof at a temperature in the range of from 700° C. to 1000° C. to form a corresponding metal silicide at said silicon apparent regions; and subsequently removing, by an etching process, material formed on said oxidized surface regions of said silicon wafer and said metal coating, which material is a reaction product of said metal and said reactive gas which is formed during said annealing step.
Claim 2
Dependent Claim
139 words
A process of forming self-aligned metal silicide on silicon apparent regions of a silicon wafer surface having oxidized regions comprising: uniformly coating said surface of said wafer with a metal selected from the group consisting of tungsten and molybdenum; annealing said metal coating in the presence of a reactive gas having a partial pressure lower than 10 2 pascals and selected from the group consisting of oxygen, NH 3 , and mixtures thereof at a temperature in the range of from 700° C. to 1000° C. to form a corresponding metal silicide at said silicon apparent regions; and subsequently removing, by an etching process, material formed on said oxidized surface regions of said silicon wafer and said metal coating, which material is a reaction product of said metal and said reactive gas which is formed during said annealing step.
Claim 3
Dependent Claim
28 words
A process according to claim 1 wherein the annealing process is carried out under atmospheric pressure conditions and said reactive gas is diluted in a neutral carrier gas.
Claim 4
Dependent Claim
31 words
A process according to claim 1 wherein said material formed on said oxidized surface regions of said silicon wafer and said metal coating comprises a nitride or oxide of said metal.
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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) | 1994-12-23 | 1995-06-24 | 1995-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-23 | 1999-06-24 | 1999-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-23 | 2003-06-24 | 2003-12-24 | $7700.00 | Window Closed / Lapsed |