Patent ID: 10710913

Abstract:
A substrate treatment unit applies surface treatment to a semiconductor substrate by using a chemical solution. The chemical solution in which metal is dissolved by substrate treatment is discharged into a storage tank and stored. A polyacid supplying unit supplies polyacid of a deletion complex with a deficient portion into the storage tank. The polyacid of deletion complex with a deficient portion is mixed into a used chemical solution containing the metal, and a pH value of the mixed solution is adjusted to between 2 and 3 to capture the metal dissolved in the chemical solution in the deficient portion of the polyacid. In addition, a counter cation is put into the chemical solution so that the polyacid in which the metal is captured is precipitated to be separated from the chemical solution, and thus the metal contained in the chemical solution during the treatment of the semiconductor substrate can be removed to enable the chemical solution to be reclaimed.