Patent US4915723A successfully refreshed from Google Patents.
US4915723A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for casting silicon with gradual cooling
Assignee: Sumco Corp
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Filing: 1989-06-30
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Granted: 1990-04-10
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Expires: 2009-06-30
Abstract
Abstract For the continuous casting of silicon, an electrically conductive bottomless crucible is circumferentially divided by axial slits and is positioned within an electrical induction coil. The slits form circumferential gaps of between 0.3 mm and 1.0 mm and the inner wall of the crucible is inclined by between 0.4° and 2.0°, so that the crucible expands in the downstream direction of movement of the silicon. In order to reduce the temperature gradient of the solidified silicon to between 20° C./cm and 100° C./cm, an additional heating element is disposed downstream of the boundary surface between the molten and solidified silicon. The crucible may be cooled by forming the crucible as a double walled cylinder and flowing a coolant therethrough.
Inventors
- 👤 Kyojiro Kaneko
- 👤 Jun-Ya Masuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:31
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; B; B22; B22D; B22D11/00; B22D11/001; B22D11/10; B22D11/11; B22D11/14; B22D11/141; B22D23/00; B22D23/06; C30B11/00; C30B11/001; C30B11/002; C30B11/003
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
96 words
An apparatus for casting silicon, comprising: an electrically conductive bottomless crucible, at least an axial part of said crucible being divided into a plurality of circumferentially spaced parts; an electrical induction coil surrounding said crucible, whereby silicon continuously moving through said crucible may be melted and subsequently solidified; and means for heating said solidified silicon, said means for heating being disposed downstream of a boundary surface level between said molten and solidified silicon, in a direction of movement of said silicon, whereby a temperature gradient in said solidified silicon in the direction of movement is reduced.
Claim 2
Independent Claim
96 words
An apparatus for casting silicon, comprising: an electrically conductive bottomless crucible, at least an axial part of said crucible being divided into a plurality of circumferentially spaced parts; an electrical induction coil surrounding said crucible, whereby silicon continuously moving through said crucible may be melted and subsequently solidified; and means for heating said solidified silicon, said means for heating being disposed downstream of a boundary surface level between said molten and solidified silicon, in a direction of movement of said silicon, whereby a temperature gradient in said solidified silicon in the direction of movement is reduced.
Claim 3
Dependent Claim
48 words
The apparatus of claim 1 wherein said heating means comprises means for maintaining the temperature gradient in said solidified silicon along said direction of movement and in a region where said solidified silicon has a temperature of at least 500° C., of between 20° C./cm and 100° C./cm.
Claim 4
Dependent Claim
19 words
The apparatus of claim 1 wherein said heating means is a radiant heating means positioned downstream of said crucible.
Claim 5
Dependent Claim
33 words
The apparatus of claim 3 wherein said radiant heating means comprises a radiant body formed of one from the group consisting of graphite, a high melting point metal and an electrically conductive ceramic.
Claim 6
Dependent Claim
31 words
The apparatus of claim 1 including axial slits in said crucible and extending to a downstream end of said crucible for dividing said crucible into the plurality of circumferentially spaced parts.
Claim 7
Dependent Claim
27 words
The apparatus of claim 1 wherein said crucible comprises a double walled cylinder, including conduit means for flowing a coolant between the double walls of said crucible.
Claim 8
Dependent Claim
23 words
The apparatus of claim 6 wherein said conduit means includes inlet and outlet conduits connected to an undivided upstream end of said crucible.
Claim 9
Dependent Claim
26 words
The apparatus of claim 1 wherein said circumferentially spaced parts of said crucible are spaced by a circumferential gap of between 0.3 mm and 1.0 mm.
Claim 10
Dependent Claim
33 words
The apparatus of claim 1 wherein an inner wall of said crucible is inclined by between 0.4° and 2.0° in said direction of movement such that said crucible expands in the downstream direction.
Claim 11
Dependent Claim
33 words
The apparatus of claim 9 wherein an inner wall of said crucible is inclined by between 0.4° and 2.0° in said direction of movement such that said crucible expands in the downstream direction.
Claim 12
Dependent Claim
19 words
The apparatus of claim 2 wherein said heating means is a radiant heating means positioned downstream of said crucible.
Claim 13
Dependent Claim
33 words
The apparatus of claim 11 wherein said radiant heating means comprises a radiant body formed of one from the group consisting of graphite, a high melting point metal and an electrically conductive ceramic.
Claim 14
Dependent Claim
31 words
The apparatus of claim 2 including axial slits in said crucible and extending to a downstream end of said crucible for dividing said crucible into the plurality of circumferentially spaced parts.
Claim 15
Dependent Claim
27 words
The apparatus of claim 2 wherein said crucible comprises a double walled cylinder, including conduit means for flowing a coolant between the double walls of said crucible.
Claim 16
Dependent Claim
23 words
The apparatus of claim 14 wherein said conduit means includes inlet and outlet conduits connected to an undivided upstream end of said crucible.
Claim 17
Dependent Claim
26 words
The apparatus of claim 2 wherein said circumferentially spaced parts of said crucible are spaced by a circumferential gap of between 0.3 mm and 1.0 mm.
Claim 18
Dependent Claim
33 words
The apparatus of claim 2 wherein an inner wall of said crucible is inclined by between 0.4° and 2.0° in said direction of movement such that said crucible expands in the downstream direction.
Claim 19
Dependent Claim
33 words
The apparatus of claim 17 wherein an inner wall of said crucible is inclined by between 0.4° and 2.0° in said direction of movement such that said crucible expands in the downstream direction.
Claim 20
Dependent Claim
11 words
The apparatus of claim 9 wherein said downstream direction is downward.
Claim 21
Dependent Claim
22 words
The apparatus of claim 9 including means positioned downstream of said heating means for pulling said solidified silicon in the downstream direction.
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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) | 1993-04-09 | 1993-10-09 | 1994-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-09 | 1997-10-09 | 1998-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-09 | 2001-10-09 | 2002-04-10 | $7700.00 | Window Closed / Lapsed |