EFFECTS OF AMINES ON COPPER ETCHING WITH H$_2$SO$_4$-$H_2O$$_2$ SYSTEMS

The corrosion of copper in $H_2$$SO_4$ $-H_2$$O_2$ etching solutions with amines was investigated at various flow rates (v). Amine additives give a retardation of $H_2$$O_2$ decompositions, increases in both corrosion rates and etch factor, and a protection of etched copper surfaces. However n-alkylamine additives acted as corrosion inhibitors at v < 10cm/s, those acted as corrosion accelerators at v of 10-220cm/s. The maximum corrosion rate was obtained with about 0.1 molal concentration of additives. Steric effects of substituted groups suppressed the acceleration of copper corrosion. The increases in both corrosion rates and flow rates gave the increase in etch factor. Corrosion rates with n-alkylamine increased in the order of ethylamine < n-propylamine < n-butylamine, those with butylamine isomers tert- < sec- < iso- < n-butylamine, and those with amine additives of different number of substituted groups tri- < di- < mono-n-propylamine, respectively.