US3882901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tubular quartz glass body
Assignee: Heraeus Schott Quarzschmelze GmbH
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Filing: 1973-07-30
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Granted: 1975-05-13
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Expires: 1993-07-30
Abstract
Abstract A tubular quartz glass body useful in carrying out diffusion processes in semiconductor technology has an inner tubular portion of high-purity synthetic quartz glass which is fused to a surrounding portion of fused quartz crystal granules or powder. Then surrounding, enveloping portion has an outer layer of finely crystalline cristobalite or in the outer surface layer thereof, crystallization promoting nuclei capable of forming an outer layer of crystalline silica. The nuclei are not semiconductor poisons and have a rate of diffusion in quartz glass less than that of sodium at elevated temperatures, such as temperatures encountered in diffusion processes which are between 1,200* and 1,380*C.
Inventors
- 👤 Karl Seiler
- 👤 Karlheinz Rau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:29
CPC Classifications
F; F16; F16L; F16L9/00; F16L9/10; F16L9/105; C; C03; C03C; C03C3/00; C03C3/04; C03C3/06; C30; C30B; C30B31/00; C30B31/06; C30B31/10; Y; Y10; Y10S; Y10S138/00; Y10S138/02; Y10T; Y10T428/00; Y10T428/13; Y10T428/131; Y10T428/1317
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
117 words
DIFFUSION TUBE COMPRISING AN INNER TUBULAR PORTION OF HIGH-PURITY SYNTHETIC QUARTZ GLASS FUSED TO A SURROUNDING PORTION OF QUARTZ GLASS, SAID INNER PORTION HAVING A WALL THICKNESS OF AT LEAST 0.05 MM, SAID SURROUNDING PORTION CONSISTING OF A QUARTZ GLASS MANUFACTURED BY FUSION OF QUARTZ CRYSTALS IN GRANULAR OR POWDER FORM AND HAVING AN OUTER LAYER OF FINELY CRYSTALLINE CRISTOBALITE OR IN THE OUTER LAYER THEREOF CRYSTALLIZATION PROMOTING NUCLEI HAVING A RATE OF DIFFUSION IN CRYSTALLINE SILICA, SAID NUCLEI HAVING A RATE OF DIFFUSION IN QUARTZ GLASS LESS THAN THAT OF SODIUM AT ELEVATED TEMPERATURES, AND SAID SURROUNDING PORTION HAVING A WALL THICKNESS AMOUNTING TO AT LEAST 50% OF THE TOTAL WALL THICKNESS OF THE DIFFUSION TUBE.
Claim 2
Dependent Claim
117 words
DIFFUSION TUBE COMPRISING AN INNER TUBULAR PORTION OF HIGH-PURITY SYNTHETIC QUARTZ GLASS FUSED TO A SURROUNDING PORTION OF QUARTZ GLASS, SAID INNER PORTION HAVING A WALL THICKNESS OF AT LEAST 0.05 MM, SAID SURROUNDING PORTION CONSISTING OF A QUARTZ GLASS MANUFACTURED BY FUSION OF QUARTZ CRYSTALS IN GRANULAR OR POWDER FORM AND HAVING AN OUTER LAYER OF FINELY CRYSTALLINE CRISTOBALITE OR IN THE OUTER LAYER THEREOF CRYSTALLIZATION PROMOTING NUCLEI HAVING A RATE OF DIFFUSION IN CRYSTALLINE SILICA, SAID NUCLEI HAVING A RATE OF DIFFUSION IN QUARTZ GLASS LESS THAN THAT OF SODIUM AT ELEVATED TEMPERATURES, AND SAID SURROUNDING PORTION HAVING A WALL THICKNESS AMOUNTING TO AT LEAST 50% OF THE TOTAL WALL THICKNESS OF THE DIFFUSION TUBE.
Claim 3
Dependent Claim
34 words
Diffusion tube of claim 1 wherein one end is hermetically sealed with a lid of quartz glass having a tubular projection and the other end is hermetically sealed with a bottom of quartz glass.
Claim 4
Dependent Claim
12 words
Diffusion tube of claim 2 wherein said bottom has a tubular projection.
References Cited (Backward Citations)
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US3382113A
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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) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |