Method for producing electronic-stage hydrofluoric acid

Abstract

The invention relates to a method for producing electronic-stage hydrofluoric acid. The method comprises the following steps: (1), preheating and roughly distilling a measured anhydrous hydrofluoric acid raw material to remove low boiling point matter; (2), using ultra-pure water to absorb hydrofluoric acid roughly distillated and exhausted from a condenser outlet to be 48 to 49 percent of hydrous hydrofluoric acid solution; (3), distilling an absorbed hydrofluoric acid semi-finished product by a fluoroplastic resin sub-boiling distiller, gasifying fluorine hydride liquid to generate ultra-pure electronic-stage hydrofluoric acid gas, condensing to be 48 to 49 percent of anhydrous hydrofluoric acid solution and remaining high boiling point matter and heavy metals at the bottom of the sub-boiling distiller; and (4), secondarily filtering the hydrofluoric acid semi-finished product output from the fluoroplastic resin sub-boiling distiller, and finally, automatically filling to prepare 48 percent of ultra-pure hydrofluoric acid finished product. The method fully utilizes the different of boiling points between the anhydrous hydrofluoric acid and various impurities in the anhydrous hydrofluoric acid to remove the impurities at different temperatures, particularly remove silicon so that the impurity content of the obtained ultra-pure hydrofluoric acid is decreased to the minimum.

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