Direct metallization using Ni-Co alloy on surface modified polyimide film

A simplified method has been examined for the formation of a thin Ni-Co all oy on polyimide film by sulfonation modification of its surface, followed b y adsorption of Ni+2 and Co+2 ions and subsequent reduction with sodium tet rahgdroborate. The sulfonic group, as a cation exchange group, was introduc ed onto the polyimide resin surface through 16MH(2)SO(4)/0.05%H2O2/1M(CH3CO )(2)O mixed solution treatment. The amount of Ni+2 and Co+2 ions adsorbed i ncreased with increase of sulfuric acid concentration. Adsorption of 1200 n mol/cm(2) of Ni+2 and 1000 nmol/cm(2) of Co+2 adsorption was observed when the surface,vas treated with 16 M sulfuric acid. The average thickness of N i and Co alloy thin film after the reduction process was estimated to be ab out 150 mm, The maximum conductivity obtained was 0.042 S/sq(11.9 Omega/sq) when the ions-adsorded surface is treated with 0.007 M sodium tetrahydrobo rate and, under this condition, it gave a bright metallic Ni-Co alloy appea rance. After reduction, each test sample permitted direct copper electropla ting at cathode current density of 2 A/dm(2).