MANAGEMENT METHOD OF ETCHING SOLUTION AND WET ETCHING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a management method of an etching solution for keeping the concentrations of HF and NH4F constant in BHF.;SOLUTION: NH3 gas is dissolved forcibly in BHF and is made to react with HF. By so doing, an increase in the concentration of HF caused by the dissociation reaction of NH4F in BHF is prevented, and the concentrations of HF and NH4F in BHF are kept constant for all times.;COPYRIGHT: (C)2001,JPO