Preparation method for electron-grade hydrofluoric acid

An electronic grade hydrofluoric acid, hydrofluoric acid technology, applied in the direction of fluorine/hydrogen fluoride, etc., can solve the problem of no tail gas recovery, increase the burden, etc., and achieve the effect of high flexibility

Active Publication Date: 2014-08-20
FUJIAN YONGJING TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, since the above-mentioned method uses substances such as potassium permanganate as an oxidant, additional impurities will be introduced into the anhydrous hydrogen fluoride liquid, thereby increasing the burden of subsequent treatment, and the above-mentioned method does not recover the tail gas generated during the preparation process

Method used

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  • Preparation method for electron-grade hydrofluoric acid

Examples

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Effect test

Embodiment 1

[0045] Such as figure 2 Shown, method of the present invention specifically comprises the following steps:

[0046] 1) Put the industrial anhydrous hydrogen fluoride liquid and pure water into the rectification tower respectively through the metering pump, mix well to form hydrofluoric acid with the first concentration (60% by mass fraction), and then add peroxide with a mass fraction of 50% Hydrogen is oxidized to oxidize impurities such as arsenic and silicon, and then rectified to obtain purified hydrogen fluoride gas at the top of the rectification tower, and the impurities remain in the bottom of the tower.

[0047]Among them, the amount of hydrogen peroxide solution is 0.04% of the mass of industrial anhydrous hydrogen fluoride liquid; in the oxidation treatment process, pump circulation is supplemented to mix hydrogen fluoride and hydrogen peroxide solution evenly, and the oxidation time is 7.5 hours; The temperature of the tower is 26°C, the temperature of the tower ...

Embodiment 2

[0055] Such as image 3 Shown, method of the present invention specifically comprises the following steps:

[0056] 1) Add the industrial anhydrous hydrogen fluoride liquid and pure water into the rectification tower respectively through the metering pump, mix well to form hydrofluoric acid with the first concentration (70% by mass fraction), and then add peroxide with a mass fraction of 50% The hydrogen solution is oxidized to oxidize impurities such as arsenic and silicon, and then rectified to obtain purified hydrogen fluoride gas at the top of the rectification tower, and the impurities remain in the bottom of the tower.

[0057] Wherein, the amount of hydrogen peroxide solution is 0.03% of the mass of industrial anhydrous hydrogen fluoride liquid; in the oxidation treatment process, pump circulation is supplemented to make hydrogen fluoride and hydrogen peroxide solution mix evenly, and the oxidation time is 6 hours; 26°C, tower body temperature 18.5°C, tower top tempera...

Embodiment 3

[0066] Such as image 3 Shown, method of the present invention specifically comprises the following steps:

[0067] 1) Add industrial anhydrous hydrogen fluoride liquid and pure water into the rectification tower respectively through metering pumps to form hydrofluoric acid at the first concentration (65% by mass fraction), and then add hydrogen peroxide with 45% mass fraction to carry out Oxidation treatment, oxidizing impurities such as arsenic and silicon, and then performing rectification to obtain purified hydrogen fluoride gas at the top of the rectification tower, and the impurities remain in the bottom of the tower.

[0068] Among them, the dosage is 0.03% of the mass of industrial anhydrous hydrogen fluoride liquid; in the oxidation treatment process, pump circulation is supplemented to mix hydrogen fluoride and hydrogen peroxide solution evenly, and the oxidation time is 7 hours; The temperature of the body is 19.5°C, the temperature at the top of the tower is 19°C,...

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Abstract

A preparation method for electron-grade hydrofluoric acid comprises the following steps: introducing an industrial waterless hydrogen fluoride liquid and pure water into a rectifying tower, so as to form hydrofluoric acid with a first concentration; then adding a hydrogen peroxide solution for obtaining arsenic and silicon impurities in hydrofluoric acid, and then performing rectification; condensing the hydrogen fluoride gas obtained through rectification to form a hydrofluoric acid liquid, performing first filtration, and performing absorbing by utilizing pure water to form hydrofluoric acid with a second concentration, and performing second filtration, so as to obtain the electron-grade hydrofluoric acid product; and absorbing tail gas with pure water, so as to prepare industrial-grade hydrofluoric acid. The preparation technology is simple, and no extra impurities are introduced; the prepared electron-grade hydrofluoric acid reaches international standard SEMI-C7 standard of semiconductor equipment and materials; the yield is high and the cost is low; and by employing one production process, the electron-grade hydrofluoric acid and analytically-pure-grade hydrofluoric acid can be both prepared.

Description

technical field [0001] The invention belongs to the field of chemical production, and in particular relates to a method for preparing electronic-grade hydrofluoric acid. Background technique [0002] Electronic grade hydrofluoric acid is a strong acid cleaning agent and corrosive agent, mainly used in the production of VLSI. At present, the main production method of electronic grade hydrofluoric acid is as follows: firstly, chemical pretreatment of industrial anhydrous hydrofluoric acid, followed by rectification, then cooling the obtained hydrogen fluoride gas, absorbing it with pure water, finally filtering and filling. Since the presence of impurity arsenic has a serious impact on the performance of electronic devices, the removal of arsenic is a key issue in the purification process of hydrofluoric acid. The usual method is to use an oxidant to convert trivalent arsenic impurities into pentavalent arsenic with a high boiling point. Compounds, commonly used oxidants are ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B7/19
Inventor 万群平吴云秀
Owner FUJIAN YONGJING TECH CO LTD
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