PRODUCTION OF CIRCUIT BOARD

摘要

PURPOSE:To prevent the generation of a harmful gas and to produce quickly a circuit board by forming an etching resist pattern on a copper layer provided on a substrate and etching the same with sulfuric acid bubbles formed by incorporating gaseous oxygen into a sulfuric acid soln. CONSTITUTION:The layer of copper is formed by plating or adhesion on the substrate 1. The etching resist is them formed to the desired pattern on the above-mentioned copper layer. The substrate 1 provided with the resulted etching resist pattern is dipped in the sulfuric acid 3 and gaseous oxygen is blown into the liquid 3 to form the sulfuric acid bubbles 2. The etching is executed by the sulfuric acid bubbles 2. The formation of the circuit board at a high etching rate is thus made possible and the treatment of the waste liquid is made possible without generating the harmful gas and with less adverse influence of the residual ions.