A method of producing electronic grade hydrofluoric acid

Abstract

The invention relates to a method for producing electronic-grade hydrofluoric acid, which specifically comprises the following steps: (1) after preheating the measured anhydrous hydrofluoric acid raw material, carry out crude distillation to remove low-boiling substances; After crude distillation, the hydrofluoric acid discharged from the outlet of the condenser is absorbed with ultrapure water, and the absorption is 48-49% aqueous hydrofluoric acid solution; Boiling distiller distillation, hydrogen fluoride liquid gasification to generate ultra-pure electronic grade hydrofluoric acid gas, condensed into 48 ~ 49% aqueous hydrofluoric acid solution, high boiling point substances and heavy metals remain at the bottom of the sub-boiling distiller; (4 ) The semi-finished product of hydrofluoric acid from the sub-boiling distiller of fluoroplastics is filtered through the second stage and finally made into 48% ultra-high-purity hydrofluoric acid finished product through automatic filling. The method of the present invention makes full use of the different boiling points of anhydrous hydrofluoric acid and impurities in anhydrous hydrofluoric acid, and removes different impurities, especially silicon, at different temperatures, so that the impurity content of the obtained ultra-high-purity hydrofluoric acid is reduced to lowest.

Description

technical field [0001] The invention relates to a method for producing electronic-grade hydrofluoric acid, in particular to a method for producing electronic-grade hydrofluoric acid with anhydrous hydrofluoric acid as the main raw material. Background technique [0002] Electronic grade hydrofluoric acid (Hydrofuloric acid, electronic grade) is also called high-purity hydrofluoric acid. Molecular formula HF, molecular weight 20.006. As one of the key basic chemical materials for the manufacture of integrated circuits (IC), electronic grade hydrofluoric acid is mainly used for chip cleaning and corrosion. very important influence. With the rapid development of electronics, information, and communication industries, the requirements for the purity and impurities of reagent hydrofluoric acid are getting higher and higher, and the demand has also increased sharply. The general electronic pure hydrofluoric acid is far from meeting the harshness of the market. The preparation o...

AI Technical Summary

Problems solved by technology

[0003] At present, the reaction of industrial anhydrous hydrofluoric acid and potassium permanganate is generally used, followed by direct distillation and purification to prepare electronic grade hydrofluoric acid, that is, high-purity hydrogen fluoride. The purity of hydrofluoric acid produced by this method is relatively low, especially hydrogen The separation of arsenic trifluoride in hydrofluoric acid is not complete, so the ultra-high-purity hydrofluoric acid produced by this method is difficult to apply in ultra-large-scale integrated circuits (microelectronics industry); at the same time, the process parameters are not easy to control in the production process

In addition, in the current preparation process of electronic grade hydrofluoric acid, because hydrogen fluoride gas cannot be completely absorbed, its tail gas emission is easy to cause pollution to the surrounding environment