| 摘要 |
PURPOSE:To obtain an etching agent which can dissolve nickel quickly to the extent of making erosion of copper negligible by allowing free chlorine ions to coexist in an acid-hydrogen peroxide type etching agent. CONSTITUTION:An etching agent for electroless Ni thin films obtained by allowing free chlorine ions to coexist in a soln. consisting essentially of >=1 kind of sulfuric acid, nitric acid and phosphoric acid and H2O2. For example, an electroless Ni plating thin film of about 0.5mu thickness is provided over the entire surface of a substrate, and a Cu circuit pattern of about 20mu is formed thereon. This substrate is etched at about 30 deg.C and under about 1.5kg/cm<2> spray pressure with a soln. consisting of about 1.5mol/l sulfuric acid, about 3.0mol/l H2O2, about 200ppm NH4Cl and about 10g/l piperidine. As a result, the Ni thin film is removed thoroughly in about 60sec and during this time, the rate of dissolution of the Cu pattern part is about <=0.5mu. |
