US4285761A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for selectively forming refractory metal silicide layers on semiconductor devices
Assignee: International Business Machines Corp
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Filing: 1980-06-30
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Granted: 1981-08-25
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Expires: 2000-06-30
Abstract
Abstract A method of forming a refractory metal silicide pattern on a substrate by (1) forming a blanket layer of SiO 2 on the substrate, (2) depositing a blanket layer of polycrystalline Si over the SiO 2 layer, (3) defining a pattern in the blanket Si layer thereby exposing selected areas of the SiO 2 layer, (4) depositing a blanket layer of refractory metal silicide on the substrate over the SiO 2 and Si layers, (5) heating the substrate in an oxidizing environment to a temperature sufficient to oxidize the metal silicide layer over the Si to form an upper layer of SiO 2 and to convert the metal silicide layer overlying the SiO 2 layer to a metal rich SiO 2 layer, and exposing the oxidized surface to an etchant that selectively etches away the metal rich SiO 2 layer.
Inventors
- 👤 Joseph J. Fatula, Jr.
- 👤 Stanley Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:19
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01306; H10D64/01308; H10D64/01312; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; Y; Y10; Y10S; Y10S148/00; Y10S148/117; Y10S148/14; Y10S148/147; Y10S438/00; Y10S438/911
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
162 words
A method of forming and defining a refractory metal silicide layer on a substrate comprising, providing a blanket layer of SiO 2 on said substrate, depositing a blanket layer of polycrystalline Si over said layer of SiO 2 , defining a pattern in said polycrystalline Si layer thereby exposing selected areas of said layer of SiO 2 , depositing a blanket layer of refractory metal silicide on said substrate over said layers of SiO 2 and said polycrystalline Si, heating the composite substrate in an oxidizing environment to a temperature and for a time to thermally oxidize the metal silicide layer overlying said polycrystalline Si to form an upper layer of SiO 2 , and to convert the metal silicide layers overlying the SiO 2 layer to a metal rich SiO 2 layer, exposing the oxidized surface of said substrate to an etchant that selectively etches said metal rich silicon dioxide layer to thereby expose said blanket layer of SiO 2 .
Claim 2
Independent Claim
162 words
A method of forming and defining a refractory metal silicide layer on a substrate comprising, providing a blanket layer of SiO 2 on said substrate, depositing a blanket layer of polycrystalline Si over said layer of SiO 2 , defining a pattern in said polycrystalline Si layer thereby exposing selected areas of said layer of SiO 2 , depositing a blanket layer of refractory metal silicide on said substrate over said layers of SiO 2 and said polycrystalline Si, heating the composite substrate in an oxidizing environment to a temperature and for a time to thermally oxidize the metal silicide layer overlying said polycrystalline Si to form an upper layer of SiO 2 , and to convert the metal silicide layers overlying the SiO 2 layer to a metal rich SiO 2 layer, exposing the oxidized surface of said substrate to an etchant that selectively etches said metal rich silicon dioxide layer to thereby expose said blanket layer of SiO 2 .
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein said metal of said refractory metal silicide is a metal selected from the group consisting of tungsten, niobium, molybdenum and tantalum, and mixtures thereof.
Claim 4
Dependent Claim
22 words
The method of claim 2 wherein said composite substrate is heated to a temperature in the range of 950° to 1,000° C.
Claim 5
Dependent Claim
18 words
The method of claim 3 wherein said polycrystalline Si layer has a thickness in the range of 2,500-4,000A.
Claim 6
Dependent Claim
39 words
The method of claim 4 wherein heating of said composite substrate is at a temperature in the range of 900°-1,050° C., the oxidizing environment is dry oxygen, and the time of heating is on the order of 30 minutes.
Claim 7
Dependent Claim
22 words
The method of claim 2 wherein said metal silicide is deposited by co-evaporating the metal and silicon by heating with dual E-beams.
Claim 8
Dependent Claim
26 words
The method of claim 2 wherein said substrate is a monocrystalline Si substrate, and said SiO 2 layer is formed by thermally oxidizing said Si substrate.
Claim 9
Dependent Claim
34 words
The method of claim 2 wherein subsequent to the etching of the oxidized metal silicide, the sidewalls of the remaining metal silicide areas are thermally oxidized to form SiO 2 films on the sidewalls.
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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) | 1984-08-24 | 1985-02-23 | 1985-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-24 | 1989-02-23 | 1989-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-24 | 1993-02-23 | 1993-08-25 | $7700.00 | Window Closed / Lapsed |