US3927697A
Expired / Lapsed
US
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Quartz glass elements
Assignee: Heraeus Schott Quarzschmelze GmbH
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Filing: 1973-07-27
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Granted: 1975-12-23
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Expires: 1993-07-27
Abstract
Abstract Quartz glass element, such as a diffusion tube useful in the production of semiconductor elements, capable of forming an outer layer of uniformly fine crystalline silica such as cristobalite or tridymite when heated to a temperature at which such crystalline silica forms containing crystallization promoting nuclei having a rate of diffusion in quartz glass less than that of sodium at elevated temperatures. Such nuclei are preferably present in the outer half of the element wall. When the quartz glass element is exposed to elevated temperatures, the nuclei promotes the formation of the outer layer of uniformly fine crsytalline silica which imparts thermal dimensional stability for extended periods of use at elevated temperatures.
Inventors
- 👤 Peter Baumler
- 👤 Gerhard Hofer
- 👤 Tassilo Korner
- 👤 Heinrich Mohn
- 👤 Karl Seiler
- 👤 Fritz Simmat
- 👤 Karlheinz Rau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:42
CPC Classifications
C; C03; C03C; C03C17/00; C03C17/34; C03C17/3411; C03C17/3417; C03B; C03B23/00; C03B23/20; C03B23/207; C03B32/00; C03B32/02; C03C10/00; C03C10/0009; C03C17/02; C03C17/22; C03C17/23; H; H10; H10P; H10P95/00; C03C2217/00; C03C2217/20; C03C2217/21; C03C2217/213; C03C2217/24; C03C2218/00; C03C2218/10; C03C2218/17; Y; Y10; Y10S; Y10S65/00; Y10S65/08; Y10S65/09; Y10T; Y10T428/00; Y10T428/13; Y10T428/131; Y10T428/1317; Y10T428/24; Y10T428/24802; Y10T428/25; Y10T428/252
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
65 words
QUARTZ GLASS ELEMENT CAPABLE OF FORMING AN OUTER LAYER OF UNIFORMLY FINE CRYSTALLINE SILICA WHEN HEATED TO A TEMPERATURE AT WHICH SUCH CRYSTALLINE SILICA FORMS CONTAINING FROM ABOUT 4 TO ABOUT 800 PPM OF CRYSTALLIZATION PROMOTING NUCLEI HAVING A RATE OF DIFFUSION IN QUARTZ GLASS LESS THAN THAT OF SODIUM AT ELEVATED TEMPERATURES, SAID NUCLEI BEING PRESENT IN THE ENTIRE VOLUME OF SAID GLASS ELEMENT.
Claim 2
Dependent Claim
65 words
QUARTZ GLASS ELEMENT CAPABLE OF FORMING AN OUTER LAYER OF UNIFORMLY FINE CRYSTALLINE SILICA WHEN HEATED TO A TEMPERATURE AT WHICH SUCH CRYSTALLINE SILICA FORMS CONTAINING FROM ABOUT 4 TO ABOUT 800 PPM OF CRYSTALLIZATION PROMOTING NUCLEI HAVING A RATE OF DIFFUSION IN QUARTZ GLASS LESS THAN THAT OF SODIUM AT ELEVATED TEMPERATURES, SAID NUCLEI BEING PRESENT IN THE ENTIRE VOLUME OF SAID GLASS ELEMENT.
Claim 3
Dependent Claim
20 words
Element of claim 1 wherein said nuclei are present in a concentration of from about 10 to about 800 ppm.
Claim 4
Dependent Claim
30 words
Element of claim 1 wherein said nuclei are selected from the group of a Group IV element, boron, aluminum, phosphorus, antimony, zinc, magnesium, calcium, gallium, and mixtures of the foregoing.
Claim 5
Dependent Claim
15 words
Element of claim 1 wherein said element is a diffusion tube for producing semiconductor elements.
Claim 6
Dependent Claim
13 words
Element of claim 1 heated to a temperature at which crystalline silica forms.
Claim 7
Dependent Claim
13 words
Element of claim 1 having a coating thereon of uniformly fine crystalline silica.
Claim 8
Dependent Claim
20 words
QUARTZ GLASS ELEMENT CONSISTING ESSENTIALLY OF A QUARTZ GLASS TUBE HAVING AN OUTER COHESIVE COATING OF UNIFORMLY FINE CRYSTALLINE SILICA.
Claim 9
Dependent Claim
20 words
QUARTZ GLASS ELEMENT CONSISTING ESSENTIALLY OF A QUARTZ GLASS TUBE HAVING AN OUTER COHESIVE COATING OF UNIFORMLY FINE CRYSTALLINE SILICA.
Claim 10
Dependent Claim
17 words
Element of claim 7 wherein said crytalline silica is selected from the group of cristobalite and tridymite.
Claim 11
Dependent Claim
15 words
Element of claim 7 wherein said element is a diffusion tube for producing semiconductor elements.
Claim 12
Dependent Claim
24 words
Diffusion tube of claim 9 wherein only a central lengthwise portion of the quartz glass tube is provided with said crystalline silica outer coating.
Claim 13
Dependent Claim
19 words
Diffusion tube of claim 4 wherein only the central section in lengthwise direction thereof contains said crystallization promoting nuclei.
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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) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |