US5024423A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor diffusion furnace inner tube
Assignee: Shin-Etsu Chemical Co Ltd
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Filing: 1989-08-15
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Granted: 1991-06-18
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Expires: 2009-08-15
Abstract
Abstract An inner tube for use in a semiconductor diffusion furnace is provided comprising a liner or diffusion tube and an insulating layer formed on the entire outer surface of the tube by spraying, typically plasma spraying. The sprayed insulating layer is resistant to deterioration and peeling, ensuring an extended period of service for the tube.
Inventors
- 👤 Fukuji Matsumoto
- 👤 Yoshio Tawara
- 👤 Michio Hayashi
- 👤 Osamu Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:28
CPC Classifications
C; C23; C23C; C23C4/00; C23C4/04; C23C4/10; C23C4/11; C30; C30B; C30B31/00; C30B31/06; C30B31/10; Y; Y10; Y10S; Y10S261/00; Y10S261/75
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
75 words
An inner tube for use in a semiconductor diffusion furnace, comprising a linear or diffusion tube formed of a silicon carbide, and an insulating layer consisting essentially of a material selected from the group consisting of alumina, silica, zirconia, zircon and mixtures thereof, said insulating layer being formed by spray depositing said material on the entire outer surface of said liner or diffusion tube at a thickness of about 0.1 mm to about 0.5 mm.
Claim 2
Dependent Claim
75 words
An inner tube for use in a semiconductor diffusion furnace, comprising a linear or diffusion tube formed of a silicon carbide, and an insulating layer consisting essentially of a material selected from the group consisting of alumina, silica, zirconia, zircon and mixtures thereof, said insulating layer being formed by spray depositing said material on the entire outer surface of said liner or diffusion tube at a thickness of about 0.1 mm to about 0.5 mm.
Claim 3
Dependent Claim
36 words
The inner tube of claim 1, wherein said spray depositing comprises instantaneously melting said material at 3000° C. or higher with a DC plasma, and causing the partially molten particles to impinge on the tube surface.
Claim 4
Dependent Claim
24 words
The inner tube of claim 1, wherein said material does not substantially differ in coefficient of thermal expansion from said liner or diffusion tube.
Claim 5
Dependent Claim
13 words
The inner tube of claim 1, wherein the insulating layer-forming material is zircon.
Claim 6
Dependent Claim
71 words
The inner tube of claim 1, wherein the insulating layer-forming material is spray deposited over the entire outer surface of the tubular member by instantaneously melting the insulating material by means of a spray gun, blowing the melted material into a mist with the aid of blowing gas, and applying the mist to the outer surface of the tube while rotating the latter about its axis, thereby forming said insulating layer.
Claim 7
Dependent Claim
25 words
The inner tube of claim 1, wherein the outer surface of the tubular member is roughened prior to spray depositing the insulating layer-forming material thereon.
Claim 8
Dependent Claim
21 words
The inner tube of claim 1, wherein the insulating layer is spray deposited by flame spraying, explosive spraying, or plasma spraying.
Claim 9
Dependent Claim
16 words
The inner tube of claim 1, wherein the insulating layer is spray deposited by plasma spraying.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-17 | 1994-12-17 | 1995-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-17 | 1998-12-17 | 1999-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-17 | 2002-12-17 | 2003-06-18 | $7700.00 | Window Closed / Lapsed |