As the design requirements of circuit boards tend to be more and more thin wire diameter, high density, small diameter, and blind hole filling, traditional DC electroplating is becoming more and more incapable of meeting the requirements, especially the coating in the center of the aperture of through-hole electroplating, usually The phenomenon that the copper layer at both ends of the aperture is too thick and the single center copper layer is insufficient. The unevenness of the plating layer will affect the effect of current transmission, which will directly lead to poor product quality. To balance the thickness of the copper on the surface, especially in the holes and microvias, lowering the current density is forced, but this prolongs the plating time to an unacceptable level. With the development of the reverse pulse plating process and suitable chemical additives for the plating process, shortening the plating time has become a reality, and these problems can be overcome by the reverse pulse plating process.

Process conditions:

    Electrolyte: CuSO5 5H2O, 100-300g/l, H2SO4, 50-150g/l

    Temperature: 20-70℃

    Current density: 500-1000A/M2 forward pulse current and three times reverse pulse current, generally forward pulse 19ms, reverse 1ms, current density and pulse time can be adjusted according to the process.

    Coating oxide: Iridium metal oxide mixture coating