EP0229322A2
Expired / Lapsed
EP
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Method and apparatus for Czochralski single crystal growing
Assignee: Shin-Etsu Handotai Co Ltd
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Filing: 1986-12-10
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Granted: —
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Expires: 2006-12-10
Abstract
Abstract The Czochralski single crystal growing of semiconductor silicon is performed in an apparatus in which a conically tapered tube having a downwardly decreasing diameter is installed to coaxially surround the growing single crystal keeping the lower end thereof with a narrow gap above the surface of the melt in the crucible. By virtue of the downward stream of a protecting gas flowing inside the tube, vapor of silicon monoxide is efficiently swept off as being carried by the gas stream so that the troubles caused by the particles of silicon monoxide deposit entering the melt is minimized. The tapered tube also serves as a heat shield and a heat conductor so that the cooling efficiency of the growing single crystal is increased and the velocity of single crystal pulling-up can be greatly increased.
Inventors
- 👤 Hirotoshi Yamagishi
- 👤 Izumi Fusegawa
- 👤 Shuji Yokota
- 👤 Junichi Hattori
- 👤 Yukio Karasawa
- 👤 Takao Abe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 12:11
CPC Classifications
C; C30; C30B; C30B15/00; C30B15/14
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
118 words
An improvement in the Czochralski method for growing a single crystal of semiconductor silicon by dipping the lower end of a seed crystal of silicon held on the lower end of a rotating shaft in molten silicon contained in a crucible and pulling up the seed crystal so as to grow a single crystal of silicon from the molten silicon on the seed crystal, which comprises coaxially surrounding the single crystal under growing with a conically tapered tube made of a heat-insulating refracttory material, of which the diameter decreases from the upper end to the lower end, and keeping the lower end of the conically tapered tube at a height close to the surface of the molten silicon.
Claim 2
Dependent Claim
118 words
An improvement in the Czochralski method for growing a single crystal of semiconductor silicon by dipping the lower end of a seed crystal of silicon held on the lower end of a rotating shaft in molten silicon contained in a crucible and pulling up the seed crystal so as to grow a single crystal of silicon from the molten silicon on the seed crystal, which comprises coaxially surrounding the single crystal under growing with a conically tapered tube made of a heat-insulating refracttory material, of which the diameter decreases from the upper end to the lower end, and keeping the lower end of the conically tapered tube at a height close to the surface of the molten silicon.
Claim 3
Dependent Claim
37 words
The improvement as claimed in claim 1 wherein the lower end of the conically tapered tube is held at a height to form a gap of 5 to 30 mm above the surface of the molten silicon.
Claim 4
Dependent Claim
120 words
An improvement in an apparatus for growing a single crystal of semiconductor silicon by the Czochralski method comprising a crucible to contain a melt of silicon, a means to rotate the crucible and a rotatable vertical shaft to hold a seed crystal of silicon on the lower end thereof, which comprises installing a conically tapered tube made of a heat-insulating refractory material coaxially held relative to the shaft in such a disposition that the diameter thereof is decreased from the upper end to the lower end and a means to control the height of the crucible in order to keep the lower end of the conically tapered tube at a height close to the surface of the melt of silicon.
Claim 5
Dependent Claim
120 words
An improvement in an apparatus for growing a single crystal of semiconductor silicon by the Czochralski method comprising a crucible to contain a melt of silicon, a means to rotate the crucible and a rotatable vertical shaft to hold a seed crystal of silicon on the lower end thereof, which comprises installing a conically tapered tube made of a heat-insulating refractory material coaxially held relative to the shaft in such a disposition that the diameter thereof is decreased from the upper end to the lower end and a means to control the height of the crucible in order to keep the lower end of the conically tapered tube at a height close to the surface of the melt of silicon.
Claim 6
Dependent Claim
31 words
The improvement as claimed in claim 3 wherein the conically tapered tube has a multi-layered structure composed of an outermost layer, an innermost layer and an intermediater heat-insulating layer sandwiched therebetween.
Claim 7
Dependent Claim
33 words
The improvement as claimed in claim 4 wherein the intermediate heat-insulating layer is made of carbon fibers and has a coefficient of thermal conduction not exceediing 10 kcal/m.hour.°C in the direction of thickness.
Claim 8
Dependent Claim
33 words
The improvement as claimed in claim 3 wherein the conically tapered tube has a surface made of a refractory material selected from the group consisting of silicon nitride, silicon carbide and boron nitride.
References Cited (Backward Citations)
No citation records indexed.
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