Method of purifying alkaline solution and method of etching semiconductor wafers

摘要

A method of purifying an alkaline solution includes dissolving metallic silicon and/or silicon compounds in the alkaline solution and non-ionizing metallic ions in the alkaline solution with reaction products generated when the metallic silicon and/or silicon compounds are dissolved therein. This purifying method is capable of remarkably decreasing metallic ions in the alkaline solution at a low-cost by an easy operation. A method of etching semiconductor wafers includes purifying an alkaline solution by non-ionizing metallic ions in the alkaline solution and etching the semiconductor wafers by using the purified alkaline solution. According to this etching method, the metallic contamination level due to the etching of the semiconductor wafers is greatly decreased, there being neither deterioration in the wafer quality nor deterioration in the characteristic of the semiconductor device.