Screening of polysilicon material and method of filling crucible

Abstract

The invention provides a polycrystalline silicon material screening and crucible filling method. The method is characterized in that a vibration screen is utilized for carrying out multi-layer screening on a polycrystalline silicon material, the screened-out polycrystalline silicon material is directly added into a quartz crucible according to specifications and dimensions, in-situ quartz crucible filling is achieved, operation time is shortened, working efficiency is improved, the dimension range of the polycrystalline silicon material can be precisely controlled, the crucible filling density is improved, influences caused by gas and pinholes on crystal ingot quality in the crystal growth process are reduced, and crystal ingot quality is improved; in addition, the problem that crystal ingot quality is affected by pollution caused by hand charging can be avoided.

Description

technical field [0001] The invention relates to a method for screening polysilicon material and filling a crucible, in particular to using a vibrating screen to screen polysilicon and directly filling a quartz crucible in situ, belonging to the field of single crystal silicon growth. Background technique [0002] More than 90% of monocrystalline silicon wafers for integrated circuits are manufactured by the Czochralski method (CZ method). The monocrystalline silicon produced by the CZ method is mainly produced according to the following steps: put the polycrystalline silicon material into a quartz crucible, and after the silicon material is melted, put the seed The crystal is immersed in the silicon melt, and the growth of the crystal is completed through necking, shoulder expansion, equal diameter and finishing. Among them, charging is a key step, the amount of charging determines the crystal yield, and the filling condition and cleanliness of the charging directly affect t...

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Problems solved by technology

[0003] The screening of existing polysilicon materials is mainly manual screening: the polysilicon that is melted to form a silicon melt is usually an irregular-shaped polysilicon block prepared by the Siemens (Siemens) method. Stored separately according to size, waiting to be added; this operation is inefficient, easy to introduce pollution, and affect the quality of crystals

[0004] There are mainly two kinds of polysilicon charging methods at present: the commonly used method is to manually preload the material outside the furnace, and then hoist it into the graphite crucible by a crane. The inclination causes pinholes and gas to appear easily, which is not conducive to the growth of crystals; another common method is to first place the quartz crucible in the graphite crucible, and then slowly add the polysilicon material into the crucible manually. Both are at least 150 kg, and it takes at least 2 hours to charge, which makes the furnace body exposed to the outside for a long time, which is easy to introduce pollution, and will affect the life of the thermal field

Regardless of the above methods, there are the following problems: polysilicon charging takes a long time and the efficiency is low; artificial charging is easy to bring in new impurities; the silicon material loaded is small, and a lot of silicon material is wasted during the charging process due to the irregular shape of the silicon material Crucible space, low output per furnace, high cost per unit mass

[0005] Small holes formed in boules can cause more serious problems while manufacturing semiconductor devices

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