METHOD AND APPARATUS FOR QUANTITATIVE ANALYSIS OF MIXED ACID SOLUTION IN ETCHING PROCESS AS WELL AS ETCHING CONTROL METHOD AND PREPARATION OF THE MIXED ACID SOLUTION

摘要

PROBLEM TO BE SOLVED: To provide a method and an apparatus, for the quantitative analysis of a mixed acid solution in an etching process, in which the concentration of every acid component can be found simply and in a short time, to provide an etching control method which can use the method and the apparatus and to provide a preparation method for the mixed acid solution. ;SOLUTION: In an analytical method for a mixed acid solution in an etching process, nitric acid is contained as a strong acid component, and, in addition, one kind out of hydrofluoric acid and/or other strong acids (excluding the nitric acid and the hydrofluoric acid) and hexafluorosilicic acid are contained. By a nonacqueous neutralization titration method, concentrations of components of the hydrofluoric acid and/or the other acids are quantitatively analyzed. Separately, only the concentration of the nitric acid is quantitatively analyzed by an ultraviolet-part absorption spectrophotometric method. The respective concentrations of the components of the nitric acid, the hydrofluoric acid and/or the other strong acids are classified and found.;COPYRIGHT: (C)1999,JPO