Method and apparatus for growing single crystal

Abstract

The present invention provides a method and apparatus for growing a single crystal by the Czochralski method, wherein a single crystal is grown with forced cooling of neighborhood of a crystal growth interface by disposing a cooling cylinder formed of copper or a metal having a heat conductivity larger than that of copper at least in the vicinity of the crystal growth interface so as to surround the single crystal under pulling and circulating a cooling medium in the cooling cylinder. Thus, there are provided a method and apparatus for growing a single crystal, which can exert cooling effect on a growing single crystal to the maximum extent so as to realize higher crystal growth rate, even when a silicon single crystal having a diameter of 300 mm or more is grown.

Description

technical field [0001] The invention relates to a single crystal growth method and a single crystal growth device for producing silicon single crystal by Czochralski method (hereinafter also referred to as CZ method and Czochralski method). technical background [0002] Hereinafter, a conventionally used method will be described by taking the growth of a silicon single crystal as an example. The single crystal growth device used in the production of silicon single crystals by the CZ method is generally equipped with a crucible that accommodates the raw material melt and can move up and down in the main chamber for growing single crystals, and a heater arranged around the crucible. The top of the chamber is connected to a crystal pulling chamber for storing and taking out the grown single crystal. When using this single crystal growth device to produce a single crystal, the seed crystal is immersed in the raw material melt, and it is rotated and pulled up to grow a rod-shape...

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Problems solved by technology

However, if liquids such as water, which are generally used as cooling media, are close to the melt surface heated to a high temperature exceeding 1000°C, it may induce a water vapor explosion and cause danger. This device separates the cooling conduit from the melt surface to ensure safety.

[0010] However, with the development of large-diameter silicon wafers, especially the mass production of wafers with a diameter of 300 mm is currently under review, crystal cooling using the above-mentioned cooling structure is still insufficient, and it is difficult to increase the crystal growth rate, resulting in The fact that crystallization productivity is reduced is very clear

[0011] That is to say, as the cooling mechanism described in JP-A-8-239291, since the cooling member with high thermal conductivity can be brought close to the surface of the silicon crystal melt, a certain degree of cooling effect can be obtained. The problem is that in order to cool the cooling member, the cooling duct through which the liquid refrigerant circulates, when the crucible containing the melt rises to the highest possible point, it is limited by the need to be sufficiently away from the surface that cannot contact the melt, so there is cooling of the cooling medium. The problem that the effect is not easily transmitted to the end of the cooling member

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