Preparation method of electronic-grade hydrofluoric acid for semiconductor

The invention discloses a preparation method of electronic-grade hydrofluoric acid for semiconductors, which comprises the following steps: a, preheating and gasifying a liquid anhydrous hydrogen fluoride raw material, enabling gasified hydrogen fluoride to sequentially pass through a first-stage sodium fluoride adsorption column and a second-stage sodium fluoride adsorption column, and converting part of sodium fluoride into sodium hydrogenfluoride, the unadsorbed tail gas is absorbed by sodium hydroxide alkali liquor; b, the sodium fluoride adsorption column is subjected to first-section heating to desorb free moisture and silicon tetrafluoride gas, and heat preservation is conducted for 1 h; desorbed gas enters tail gas absorption; c, continuously heating the sodium fluoride adsorption column to perform second-stage hydrogen fluoride desorption, and preserving heat for 1 hour to decompose sodium hydrogenfluoride into high-temperature hydrogen fluoride gas; and d, absorbing the hydrogen fluoride high-temper