Method for preparing electronic grade ultrahigh purity hydrofluoric acid

Abstract

The invention provides a method for preparing electronic grade ultrahigh purity hydrofluoric acid. The method comprises the following technical steps: (1) pretreating industrial anhydrous hydrogen fluoride; (2) treating in a reboiler; (3) distilling; (4) cooling; (5) absorbing; (6) performing ion exchange adsorption; and (7) filtering. The invention has the following beneficial effects: hydrogen peroxide is used to oxidize As<3+>, thus the problem that As<3+> is difficult to remove can be completely solved; chelating agent and a weak-base anion-exchange resin system are adopted to deeply remove a small amount of metal ions and impurities; through secondary filtration, all the indexes of hydrofluoric acid can meet the requirements of the electronic grade ultrahigh purity agent; and the method of the invention can be used for large-scale production, and the technology is stable, is easy to control and is suitable for popularization.

Description

A method for preparing electronic grade ultra-high purity hydrofluoric acid technical field The invention belongs to the technical field of electronic chemicals, in particular to a preparation method of hydrofluoric acid. Background technique Hydrofluoric acid (HydrofluoricAcid, HF), relative molecular weight 20.006, is a colorless liquid with a strong pungent smell and corrosiveness. The density (25° C.) of hydrofluoric acid is 1.13 g / ml (40% by weight). Electronic grade ultra-high-purity hydrofluoric acid is an important chemical commonly used in semiconductor manufacturing. It is mainly used in large-scale integrated circuits as a cleaning agent and corrosive agent. With the continuous development of ultra-large-scale integrated circuit technology, related companies have put forward higher requirements for ultra-high-purity chemical reagents. At present, because hydrofluoric acid is used for cleaning and corrosion in large-scale integrated circuits, the existence of ...

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Problems solved by technology

Its disadvantage is that when anhydrous hydrogen fluoride is distilled from the solution, it may be polluted by volatilized potassium permanganate compounds, which will easily cause the content of potassium and manganese impurities to exceed the standard, making the product quality unstable

Chinese Invention Patent Application Publication No. CN101125639A uses a chelating agent to treat hydrofluoric acid after rectification, and some metal ions cannot be removed, which brings a certain load to the subsequent ion exchange system, shortens the life of the ion exchange resin, and is not conducive to the product. the stability of