US5075251A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tungsten silicide self-aligned formation process
Assignee: L'ETAT FRANCAIS
•
Filing: 1989-09-08
•
Granted: 1991-12-24
•
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 04:38
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.
References Cited (Backward Citations)
US3993808A
Cited
US4425700A
Cited
US4622735A
Cited
US4716131A
Cited
JPS62126631A
Cited
JPS62200717A
Cited
US4746219A
Cited
EP0264692A2
Cited
US4962414A
Cited
US4847111A
Cited
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 |