ETCHING TREATING LIQUID FOR SYNTHETIC QUARTZ GLASS JIG AND ETCHING METHOD USING THE LIQUID

摘要

PROBLEM TO BE SOLVED: To easily remove heavy metal impurities which intrude into microcracks or deposit on a rough surface by using a liquid comprising a mixture soln. of hydrofluoric acid and an inorg. acid or org. acid except for hydrofluoric acid. ;SOLUTION: This etching treating liquid is prepared by mixing hydrofluoric acid with an inorg. acid except for hydrofluoric acid or with an org. acid, and water in a specified proportion, and the liquid is controlled to have ≤25% hydrofluoric acid concn. and ≤30% inorg. or org. acid concn. When the inorg. acid or org. acid in the etching treating liquid is a strong acid, the increase in the etching rate is large, while if a weak acid is used, the increase in the etching rate is not large but the removing rate of heavy metal impurities is increased. In an etching treatment of a synthetic quartz glass jig produced by mechanical processing, the cleaning efficiency is further improved by dipping the jig in the etching treating liquid and by heating at 30 to 40°C. As for the inorg. acid used together, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrogen peroxide or the like is used, and as for the org. acid, acetic acid, formic acid or the like is used.;COPYRIGHT: (C)1999,JPO