PURPOSE: To use a copper oxide as a copper replenishing source for the purpose of prolonging the life of the plating liquid and to obtain a high-quality plating film free from copper projection defects.
CONSTITUTION: After the copper oxide 5 is dissolved to some extent in a copper oxide dissolving cell 2, the dissolution of the copper oxide powder is further accelerated by a mixing machine 4. The copper oxide which is not yet completely dissolved by the, mixing is filtered by a filter 7, by which the high-quality plating film free from the copper projection defects is obtd. Since the copper oxide is used, the life of the plating liquid is prolonged. As a result, the life of the plating liquid is prolonged and further the high-quality plating liquid free from the copper projection defects is obtd.
TAKADA YUJI
TOBA RITSUJI
