Purification method of silicon tetrafluoride prepared by using fluoride and silicon source power as raw materials

A technology of silicon tetrafluoride and purification method, applied in the direction of halogenated silicon compounds, halogenated silanes, etc., can solve the problem of high cost of silica gel

Active Publication Date: 2010-07-14
ZHEJIANG ZHONGNING SILICON IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The cost of silica gel used in this p

Method used

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  • Purification method of silicon tetrafluoride prepared by using fluoride and silicon source power as raw materials
  • Purification method of silicon tetrafluoride prepared by using fluoride and silicon source power as raw materials
  • Purification method of silicon tetrafluoride prepared by using fluoride and silicon source power as raw materials

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0027] Example 1

[0028] The crude silicon tetrafluoride produced with fluoride and silicon source powder as raw materials is passed through a light-removing tower to remove nitrogen, oxygen, carbon dioxide and carbon monoxide at -150 ° C. The operating pressure of the light-removing tower is 0.1MPa; The bottom liquid phase material is passed into the weight-removing tower, the moisture and hydrogen fluoride are removed from the bottom of the tower at a temperature of -20 ℃, the silicon tetrafluoride gas is discharged through the top of the tower, and the operating pressure of the weight-removing tower is 0.5MPa; The discharged silicon tetrafluoride gas passes through a three-stage adsorption tower, and the adsorption tower is equipped with activated carbon, and the moisture content of the activated carbon is below 0.8%. The hexafluorodimethylsilyl ether is removed by adsorption; the purified silicon tetrafluoride gas comes out of the adsorption tower and is connected to the ...

Example Embodiment

[0030] Example 2

[0031] The crude silicon tetrafluoride produced from fluoride and silicon source powder is passed through a light-removing tower to remove nitrogen, oxygen, carbon dioxide and carbon monoxide at -50°C. The operating pressure of the light-removing tower is 3MPa; The bottom liquid phase material is passed into the weight-removing tower, the moisture and hydrogen fluoride are removed from the bottom of the tower at a temperature of 80 ° C, and the silicon tetrafluoride gas is discharged through the top of the tower, and the operating pressure of the weight-removing tower is 5MPa; The silicon fluoride gas passes through the three-stage adsorption tower, and the adsorption tower is equipped with activated carbon, and the quasi-dry humidity of the activated carbon is below 0.8%. The hexafluorodimethylsilyl ether is removed by adsorption; the purified silicon tetrafluoride gas comes out of the adsorption tower and is connected to the compressor pipeline, compressed...

Example Embodiment

[0033] Example 3

[0034] The crude silicon tetrafluoride produced with fluoride and silicon source powder as raw materials is passed through a light-removing tower to remove nitrogen, oxygen, carbon monoxide and carbon monoxide at -120 ° C. The operating pressure of the light-removing tower is 1MPa; The liquid material at the bottom is passed into the weight-removing tower, the moisture and hydrogen fluoride are removed from the bottom of the tower at a temperature of -15°C, and the silicon tetrafluoride gas is discharged through the top of the tower, and the operating pressure of the weight-removing tower is 1MPa; The silicon tetrafluoride gas passes through the three-stage adsorption tower, and the adsorption tower is equipped with activated carbon, and the quasi-dry humidity of the activated carbon is below 0.8%. The hexafluorodimethylsilyl ether is removed by adsorption; the purified silicon tetrafluoride gas comes out of the adsorption tower and is connected to the compr...

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Abstract

The invention discloses a purification method of silicon tetrafluoride prepared by using fluoride and silicon source power as raw materials, which comprises the following steps: 1. removing nitrogen, oxygen and carbon dioxide in coarse silicon tetrafluoride produced by using the fluoride and the silicon source power as the raw materials through a lightness-removing column at the temperature of 150 DEG C below zero to 50 DEG C below zero, wherein the pressure of the lightness-removing column is 0.1 to 3MPa; 2. introducing a liquid-phase material at the bottom of the lightness-removing column into a weight-removing column, removing moisture and fluorine hydride from the column bottom at the temperature of 20 to 80 DEG C below zero, and discharging silicon tetrafluoride gas from the column top, wherein the pressure of the weight-removing column is 0.5 to 5MPa; 3. enabling the silicon tetrafluoride gas to pass through a triple-stage absorption column in which activated carbon is filled to absorb and remove dimethyl silicon ether hexafluoride; and 4. connecting the purified silicon tetrafluoride gas from the absorption column into a compressor pipeline and introducing into a storage tank for standby after being compressed to 2.5MPa. The coarse silicon tetrafluoride can be finally purified to the purity of more than 99.5% by the invention, thereby the use requirements of electron and semiconductor trades are completely satisfied.

Description

technical field [0001] The invention relates to a preparation method of a compound, in particular to a purification method of silicon tetrafluoride gas required for producing silane. Background technique [0002] Silicon tetrafluoride, whose molecular formula is SiF4, is mainly used in the electronics and semiconductor industries as silicon nitride etchant, P-type dopant, diffusion silicon source for epitaxial deposition, etc. It can also be used to prepare electronic grade silane or silicon. [0003] Regarding the production method of silicon tetrafluoride, many methods are known. [0004] The patent of the Italian company EniChem introduces a kind of hydrogen with a mass fraction of 12% to 20%. 2 SiF 6 A process for producing silicon tetrafluoride by reacting an aqueous solution with 96%-99% concentrated sulfuric acid in a reactor at 90-120°C and 40-50kPa, and then washing with cold 96% sulfuric acid. [0005] The Showa Denko patent reports a method for producing high-p...

Claims

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Application Information

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IPC IPC(8): C01B33/107
Inventor 杨建松陈德伟栗广奉耿金春孔祥云
Owner ZHEJIANG ZHONGNING SILICON IND
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