METHOD AND SYSTEM FOR ETCHING

摘要

PROBLEM TO BE SOLVED: To prolong the service life of an etchant in an etching method where an etchant composed essentially of ferric chloride is supplied to a material to be etched while circulating the etchant and also to stabilize the quality of the material to be etched after the etching treatment. SOLUTION: A treatment tank having a hydrometer, a diluted-solution- supplying means and a metal (ferrous)-ion-detecting means is provided to a pipe which connects a spray means for spraying the etchant onto the material to be etched to a storage part for storing the etchant running down the surface of the material to be etched and circulates the etchant. When the specific gravity of the etchant exceeds a set value, pure water is supplied from the diluted- solution-supplying means into the above treatment tank and the specific gravity of the etchant is returned to a value within the predetermined set range and the specific gravity can be substantially fixed. At the point of time when the ferrous ion concentration in the etchant exceeds a set value, the etchant is discharged out of the system.