US5108952A
Expired / Lapsed
US
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Method of depositing a tungsten film
Assignee: Oki Electric Industry Co Ltd
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Filing: 1990-07-30
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Granted: 1992-04-28
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Expires: 2010-07-30
Abstract
Abstract In a method of depositing a tungsten film on a gate oxide by means of laser CVD, using WF 6 and H 2 as raw material gases, the H 2 /WF 6 flow ratio lies within the range 10-100, and the volumeric flow rate of the WF 6 , which is defined as the ratio of the flow rate of WF 6 to the total pressure, lies within the range 0.04-0.01 sccm/Pa, so that the supply of WF 6 determines the deposition rate of the W film, whereby a low stress W film is obtained. Accordingly, peeling of the W film at the interface with the SiO 2 film and cracks can be avoided.
Inventors
- 👤 Hideaki Matsuhashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:24
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01316; H10P; H10P14/00; H10P14/40; H10P14/412
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
135 words
A method of depositing a stable film of tungsten (W) having low tensile stress used as a gate metal in semiconductor devices, said film being deposited by means of laser chemical vapor deposition (CVD) on a substrate using WF 6 and H 2 as raw material gases, said film being continuous throughout the entire surface of said substrate, wherein the ratio of the flow rate of said H 2 to the flow rate of said WF 6 gas lies within the range of 10-100, and the volumetric flow rate of WF 6 , which is defined as the ratio of the flow rate of WF 6 to the total pressure, lies within the range of 0.04-0.01 sccm/Pa so that the supply of WF 6 determines the rate of reaction for formation of the W film.
Claim 2
Independent Claim
135 words
A method of depositing a stable film of tungsten (W) having low tensile stress used as a gate metal in semiconductor devices, said film being deposited by means of laser chemical vapor deposition (CVD) on a substrate using WF 6 and H 2 as raw material gases, said film being continuous throughout the entire surface of said substrate, wherein the ratio of the flow rate of said H 2 to the flow rate of said WF 6 gas lies within the range of 10-100, and the volumetric flow rate of WF 6 , which is defined as the ratio of the flow rate of WF 6 to the total pressure, lies within the range of 0.04-0.01 sccm/Pa so that the supply of WF 6 determines the rate of reaction for formation of the W film.
Claim 3
Independent Claim
132 words
A method of depositing a film of tungsten on a semiconductor device by means of laser chemical vapor deposition, comprising the steps of: placing the semiconductor substrate in a reaction chamber, evacuating the reaction chamber, introducing into the reaction chamber WF 6 and H 2 gases, applying a laser beam to the space immediately above the semiconductor substrate, wherein the ratio of the flow rate of said H 2 to the flow rate of said WF 6 gas lies within the range of 10-100, and the volumetric flow rate of WF 6 , which is defined as the ratio of he flow rate of WF 6 to the total pressure, lies within the range of 0.04-0.01 sccm/Pa so that the supply of WF 6 determines the deposition rate of the W film.
Claim 4
Independent Claim
132 words
A method of depositing a film of tungsten on a semiconductor device by means of laser chemical vapor deposition, comprising the steps of: placing the semiconductor substrate in a reaction chamber, evacuating the reaction chamber, introducing into the reaction chamber WF 6 and H 2 gases, applying a laser beam to the space immediately above the semiconductor substrate, wherein the ratio of the flow rate of said H 2 to the flow rate of said WF 6 gas lies within the range of 10-100, and the volumetric flow rate of WF 6 , which is defined as the ratio of he flow rate of WF 6 to the total pressure, lies within the range of 0.04-0.01 sccm/Pa so that the supply of WF 6 determines the deposition rate of the W film.
Claim 5
Dependent Claim
27 words
A method according to claim 2, wherein the semiconductor substrate has a silicon dioxide film, and said film of tungsten is formed on the silicon dioxide film.
Claim 6
Dependent Claim
26 words
A method according to claim 2, wherein the WF 6 and H 2 gases are introduced to partial pressures of 4 Pa and 100 Pa, respectively.
Claim 7
Dependent Claim
19 words
A method according to claim 2, wherein the tungsten film is formed to a thickness of about 3000 Angstrom.
Claim 8
Dependent Claim
21 words
A method according to claim 2, wherein the substrate is heated to about 400° C. while the laser CVD is performed.
Claim 9
Dependent Claim
19 words
A method according to claim 2, wherein the wavelength of the laser is selected to excite the reaction gases.
Claim 10
Dependent Claim
19 words
A method according to claim 7, wherein the substrate is moved or rotated with respect to the laser beam.
References Cited (Backward Citations)
US4404235A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-04-28 | 1995-10-28 | 1996-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-28 | 1999-10-28 | 2000-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-28 | 2003-10-28 | 2004-04-28 | $7700.00 | Window Closed / Lapsed |