Electron-grade high purity hydrofluoric acid preparation method

A hydrofluoric acid, electronic-grade technology, applied in fluorine/hydrogen fluoride and other directions, can solve the problems of difficult separation of arsenic trifluoride impurities and difficulty in ensuring product quality.

Inactive Publication Date: 2009-12-09
广东光华化学厂有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, the main production method of ultra-clean electronic grade hydrofluoric acid is to absorb anhydrous hydrogen fluoride with water and prepare hydrofluoric acid with a concentration of 40% by weight, and then make a semi-finished product of hydrofluoric acid through rectification in a rectification kettle and hydrogen fluoride absorption, and then pass Ultra-clean filtration to produce ultra-clean hydrofluoric acid; this production method utilizes the high boiling point of most impurities to remove, but the arsenic trifluoride impurity in hydrofluoric acid is difficult to separate, and it is easy to azeotrope with hydrofluoric acid
[0003] Patents CN101003361, CN101125639, CN1931709, etc. use industrial anhydrous hydrogen fluoride liquid to pass into the rectification kettle, add potassium permanganate, and pass the purified hydrogen fluoride gas out of the rectification kettle into the cooler for cooling and filtering; It is difficult to guarantee product quality by removing metal ions in depth with acid

Method used

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  • Electron-grade high purity hydrofluoric acid preparation method

Examples

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Comparison scheme
Effect test

Embodiment 1

[0022] Place 500kg of liquid anhydrous hydrogen fluoride in a high-position stirring tank, and add KMnO with a mass percent concentration of 3%. 4 Aqueous solution, the addition amount is 10kg; at the same time, add 10kg of NaOH aqueous solution with a concentration of 3% by mass, fully stir and let it stand for 0.5 hours, then put it into a rectification tower, the temperature at the bottom of the tower is 60°C, and the rectification temperature is 30°C Use ultrapure water to rectify and purify hydrogen fluoride gas to absorb again, make hydrofluoric acid semi-finished product, its concentration 42% (w / w), weight 965kg; Bed multi-cycle ion exchange, ultrafiltration membrane separation, to obtain electronic grade high-purity hydrofluoric acid product 1, weighing 948kg, the technical indicators are shown in Table 1.

Embodiment 2

[0024] Place 300kg of liquid anhydrous hydrogen fluoride in a high-position stirring tank, and add KMnO with a mass percentage concentration of 3%. 4 Aqueous solution, the addition amount is 6kg; at the same time, add 6kg of NaOH aqueous solution with a concentration of 3% by mass, fully stir and let it stand for 1 hour, then put it into the rectification tower, the temperature at the bottom of the tower is 65°C, and the rectification temperature is 29°C; Use ultra-pure water to absorb the hydrogen fluoride gas obtained by rectification and purification to make a semi-finished product of hydrofluoric acid, with a concentration of 45% (w / w) and a weight of 515kg; the semi-finished product of hydrofluoric acid is made of polymer chelating adsorbent, mixed bed Multi-cycle ion exchange, ultrafiltration membrane separation, to obtain electronic grade high-purity hydrofluoric acid product 2, weighing 506kg, the technical indicators are shown in Table 1.

[0025] Table 1 Measurement ...

Embodiment 3

[0028] Place 500kg of liquid anhydrous hydrogen fluoride in a high-position stirring tank, and add KMnO with a mass percent concentration of 4%. 4 Aqueous solution, the addition amount is 20kg; at the same time, add 20kg of NaOH aqueous solution with a mass percentage concentration of 5%, fully stir and let it stand for 1 hour, then put it into a rectification tower, the temperature at the bottom of the tower is 65°C, and the rectification temperature is 19°C; Use ultra-pure water to absorb the hydrogen fluoride gas obtained by rectification and purification to make a semi-finished product of hydrofluoric acid, with a concentration of 45% (w / w) and a weight of 965kg; the semi-finished product of hydrofluoric acid is made of polymer chelating adsorbent and mixed bed Multi-cycle ion exchange and ultrafiltration membrane separation to obtain electronic grade high-purity hydrofluoric acid with a weight of 940kg.

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Abstract

The invention discloses an electron-grade high purity hydrofluoric acid preparation method, comprising the following steps: (1) preprocessing liquid anhydrous hydrogen chloride; (2) rectifying liquid anhydrous hydrogen chloride; (3) preparing a hydrofluoric acid semifinished product; (4) preprocessing the hydrofluoric acid semifinished product; (5) removing metal ions in the hydrofluoric acid semifinished product; and (6) obtaining electron-grade high purity hydrofluoric acid. The production technology of the invention avoids the onerous processes of absorbing hydrofluoric acid with anhydrous hydrogen fluoride and re-rectification and directly uses anhydrous hydrogen fluoride liquid for rectification purification; the production technology can effectively remove inorganic impurities such as arsenic trifluoride, SO2, SO3, H2SiF6 and the like, deeply remove various metallic impurities and solid particles, and purify the industrial hydrofluoric acid to refine the ultraclean high purity hydrofluoric acid agent which reaches the quality of ultraclean electron-grade hydrofluoric acid and meets the SIME-C8 standard, thus being applicable to the production of super precision integrated circuit.

Description

technical field [0001] The invention belongs to the field of chemical production, in particular to a method for preparing electronic-grade high-purity hydrofluoric acid. Background technique [0002] Hydrofluoric acid (hydrofluoric, HF), with a relative molecular weight of 20.1, is a colorless transparent liquid with strong acidity; it is strongly corrosive to metal and glass and is highly toxic. The hydrofluoric acid density (25° C.) was 1.13 g / ml (40% by weight). Ultra-clean electronic grade hydrofluoric acid is a strong acid cleaning and corrosive agent, mainly used in the production of ultra-large-scale integrated circuits. At present, the main production method of ultra-clean electronic grade hydrofluoric acid is to absorb anhydrous hydrogen fluoride with water and prepare hydrofluoric acid with a concentration of 40% by weight, and then make a semi-finished product of hydrofluoric acid through rectification in a rectification kettle and hydrogen fluoride absorption, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B7/19
Inventor 肖定军陈旭波谭泽余军文
Owner 广东光华化学厂有限公司
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