Research on microetchant for black oxide pretreatment of PCB lining

A new microetchants of black oxide pretreatment for PCB lining was developed, its formula being as follows:100 g/L H2SO4, 25 g/L H2O2, 0.4 g/L stable agent A (hydroxyl containing organic acid), 0.4 g/L accelerant A (the same as stabilization agent A), 0.5 g/L aliphatic amine EO-PO block polymer. The effects of temperature and copper ion content on etching rate were discussed. The test results showed that, as high copper ion content 25 g/L is used, the etching rate of the microetchant becomes stable, reaching 1.4 μm/min or more. The copper surface is level and uniform after microetching with the microetchant, completely satisfying the production demand for black oxide pretreatment.