Method for measuring the active koh concentration in a koh etching process

摘要

The invention relates to a method for in-line measuring the active KOH concentration in a KOH etching process in which process silicon hydroxide is produced by a reduction reaction according to the formula: 2K+ (aq.)+2OH- (aq.)+2H2O+Si->2K+ (aq.)+H2SiO42- (aq.)+2H2 (g). The total concentration of KOH bath is measured by using a refractometer and the measurement result is corrected by the estimated K2H2SiO4 concentration.