Preparation method of electronic-grade polycrystalline silicon

A technology of polysilicon and electronic grade, applied in the direction of silicon, etc., can solve the problems of low purity of raw materials and failure to meet the production requirements of electronic grade high-purity polysilicon for integrated circuits, etc., and achieve mature and simple process flow, stable product quality and low energy consumption Effect

Active Publication Date: 2018-08-31
CHINA ENFI ENGINEERING CORPORATION +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The main purpose of the present invention is to provide a method for preparing electronic-grade polysilicon to solve the problem that the purity of raw materials used in the existing polysilicon preparation process is low and cannot meet the requirements for the production of electronic-grade high-purity polysilicon for integrated circuits

Method used

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Examples

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Comparison scheme
Effect test

preparation example Construction

[0019] As described in the background art, the purity of raw materials used in the existing polysilicon preparation process is relatively low, which cannot meet the requirements for the production of electronic-grade high-purity polysilicon for integrated circuits. In order to solve the above technical problems, the present invention provides a method for preparing electronic-grade polysilicon, comprising: purifying trichlorosilane liquid and / or chlorosilane liquid to obtain trichlorosilane, and the chlorosilane liquid includes trichlorosilane hydrogen silicon; and using hydrogen to carry out a reduction reaction with the trichlorohydrogen silicon to obtain the electronic grade polysilicon. The above purification steps include: subjecting the trichlorosilane liquid and / or the chlorosilane liquid to a first rectification process to obtain a crude trichlorosilane product; complexing the above crude trichlorosilane product with a complexing agent to obtain The impurity in the cru...

Embodiment 1

[0042] 1. Purification steps of trichlorosilane

[0043] 1) The first rectification process. The trichlorosilane liquid and / or the chlorosilane liquid are subjected to a first rectification process to obtain a crude trichlorosilane product, the temperature in the first rectification process is 65-98° C., and the apparent pressure is 0.3-0.32 MPa.

[0044] 2) Complexation reaction. The crude product of trichlorosilane is subjected to a complex reaction with complexing agent benzaldehyde to obtain an intermediate product. The temperature of complexation reaction is 50° C., the pressure is 0.2 MPa, and the weight ratio of trichlorosilane to complexing agent benzaldehyde is 100:1.

[0045] 3) The second rectification process. Pass the above-mentioned intermediate product into the first rectification tower, the second rectification tower and the third rectification tower connected in series to carry out the second rectification, wherein the temperature in the first rectification...

Embodiment 2

[0056] The difference with Example 1 is: the complexing agent is cinnamaldehyde.

[0057] After the second rectification process, the purity of the obtained trichlorosilane is 99.95wt%, and after the reduction reaction, the purity of the obtained electronic grade polysilicon is 11N.

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Abstract

The invention provides a preparation method of electronic-grade polycrystalline silicon. The preparation method includes the steps: purifying a trichlorosilane liquid and / or chlorosilane liquid to obtain trichlorosilane, wherein the chlorosilane liquid includes trichlorosilane; and carrying out a reducing reaction with hydrogen and trichlorosilane to obtain electronic-grade polycrystalline silicon. The purification step includes the steps: carrying out primary rectification process of the trichlorosilane liquid and / or chlorosilane liquid, to obtain a crude product of trichlorosilane; carryingout a complexing reaction of the crude product of trichlorosilane with a complexing agent to convert impurities in the crude product of trichlorosilane into complexes, to obtain intermediate products,wherein the impurities include one or more of the group composed of B, P, Fe and Al; and carrying out secondary rectification process of the intermediate products, to remove the complexes, and thus obtaining trichlorosilane. The high-purity trichlorosilane raw material undergoes reduction reaction with hydrogen to obtain the electronic-grade polycrystalline silicon. The preparation method has theadvantages of mature and simple technological process, low energy consumption, stable product quality and the like.

Description

technical field [0001] The invention relates to the field of polysilicon production, in particular to a method for preparing electronic-grade polysilicon. Background technique [0002] There are two main processes for global polysilicon production, namely the improved Siemens process and the silane process. From the perspective of production capacity comparison, the improved Siemens process accounts for more than 90% of the total production capacity, and the silane process accounts for less than 10%. [0003] The improved Siemens process is improved from the traditional Siemens process, and it is the current mainstream and mature production technology for solar-grade polysilicon. The improved Siemens method is a technology that uses trichlorosilane and hydrogen to undergo a vapor deposition reaction in a CVD reduction furnace to generate polysilicon. The main process of this technology is polysilicon reduction, dry recovery, rectification purification and hydrogenation of s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/03
CPCC01B33/03C01P2006/80
Inventor 严大洲杨永亮万烨汤传斌张升学姜利霞石何武张志刚赵雄
Owner CHINA ENFI ENGINEERING CORPORATION
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