Production process and production device of electronic-grade hydrofluoric acid

Abstract

The invention discloses a production process and a production device of electronic-grade hydrofluoric acid, and belongs to the technical field of production processes and equipment of electronic-grade chemicals. According to the production device, a quantitative feeding assembly is arranged on a conveying pipeline, and a structural mode that after double falling film evaporation devices are connected in series for use, an air inlet pipe on a condensing tower is connected with a second falling film evaporation device in series for use is combined; the production process comprises the following steps: quantitatively adding materials according to a molar ratio in a liquid conveying process, carrying out a falling film evaporation oxidation reaction in a first falling film evaporation device, carrying out negative-pressure low-temperature evaporation in a second falling film evaporation device, and carrying out condensation reflux in a condensing tower, so the reaction time of arsenic in hydrofluoric acid and an oxidizing agent can be shortened, and corrosion to a storage tank is avoided; meanwhile, hydrofluoric acid can be evaporated and purified in a negative-pressure low-temperature evaporation mode, the number, length and loss of the demister are reduced, and the safety of evaporation operation is improved.

Description

technical field [0001] The invention relates to a production process and a production device for hydrofluoric acid, in particular to a production process and a production device for electronic-grade hydrofluoric acid, and belongs to the technical field of electronic-grade chemical production process and equipment. Background technique [0002] Electronic grade hydrofluoric acid, also known as ultra-pure hydrofluoric acid, is one of the key basic chemical materials in the manufacturing process of large-scale integrated circuits. It is used in many processes such as cleaning, photolithography, etching and degumming. Purity and cleanliness have a very important impact on the yield, electrical performance and reliability of integrated circuits. The purity of industrial-grade anhydrous hydrofluoric acid is as high as 99.95% or higher, but it contains anion and cation impurities formed by silicon, phosphorus, nitrogen, chlorine, sulfur, arsenic, boron and metal elements. The elec...

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Problems solved by technology

The disadvantages of the device and treatment method for oxidation and impurity removal in the above-mentioned prior art are: after the oxidant solution is added into the storage tank, it needs to be fully mixed through the large circulation reaction of the liquid in the storage tank, and the mixing and reaction time is relatively long, generally about 4 hours. -5h, time-consuming and energy-consuming; in addition, because the oxidant solution generally uses water as a solvent, especially the commonly used potassium permanganate solution, when the oxidant aqueous solution is added to the storage tank, the anhydrous hydrofluoric acid will be affected by water. Aqueous hydrofluoric acid is formed, which can easily corrode the inner wall of the steel storage tank. Usually, the storage tank needs to be scrapped and replaced after 4-5 years of use. However, the replacement of the storage tank is inconvenient and economical. also larger

The disadvantages of the above-mentioned devices and treatment methods for evaporation and condensation in the prior art are that the evaporation temperature used for evaporation is generally superheated evaporation, that is, the evaporation temperature is usually higher than the boiling temperature of hydrogen fluoride in hydrofluoric acid. Use an evaporation temperature of 50-60°C, or even use the temperature of water vapor for this evaporation temperature

In this way, the content of liquid droplets in the hydrogen fluoride vapor evaporated at high temperature is relatively high, so multiple demisters must be used in combination at the top of the condenser or a longer demister can be used to remove all the liquid droplets, resulting in a large footprint of the equipment. Larger; at the same time, the higher evaporation temperature leads to higher operating temperature of evaporation, higher energy consumption, and lower safety of the production process

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