High purity hydrofluoric acid for semiconductor.

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Other Title
  • 半導体用高純度フッ化水素酸
  • ハンドウタイヨウ コウジュンド フッカ スイソサン

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Description

A preparation of high purity hydrofluoric acid for semiconductor was studied, on (1) a method of fractional distillation of a highly concentrated hydrofluoric acid by a new rectifying column made of fluorine resin, and (2) fates of phosphate and arsenic in the course of purification and analysis which were followed by the use of 32P and 74As.<BR>As the result, high purity hydrofluoric acid (concentration 51%; fluosilicic acid 0.0004%; phosphate 0.000005%; arsenic 0.000001%) was obtained with 80% yield by a distillation of 1 kg of raw 68% hydrofluoric acid (fluosilicic acid 0.2%; phosphate 0.003%; arsenic 0.002%; sulfate 0.01%) at 2425°C for 24 hours with 50 g of (NH4)2S2O8, 20 g of Ag2SO4 and 50 g of Na2CO3.<BR>Repeated distillations gave an acid almost free from phosphate and arsenic.

Journal

  • BUNSEKI KAGAKU

    BUNSEKI KAGAKU 17 (9), 1087-1091, 1968

    The Japan Society for Analytical Chemistry

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