A HIGH THROW BRIGHT ACID COPPER FOR RACK PLATING OF PRINTED CIRCUIT BOARDS

A novel acid copper plating process produces a bright deposit with excellent throwing power from a sulfate system. Particular attention is placed on the effect of phenyl poly disulfide propane sulfonate, PEG and 2-Mercapto benzimidazole on the copper coating and the appropriate concentration of these additives is 20 mg/L, 60 mg/L and 0.6mg/L, respectively. The bright smooth copper layer may be deposited at 1-5 A/ dm(2) and 20-45 square in this solution. The throwing power can reach 91.5% and the deepening plating ability of hole with L/d of 5 is 100%, which shows that this process may be used for rack plating applications of printed circuit board. The corruption rate of the coating is 0.0548g/(m(2).h) in 5%NaCl solution. The XRD results show that the crystal face is mainly assigned to the (112) crystal face on the deposits. The SEM results show that the appearance is uniform and the grain is superfine.