Effect of Different Additives on the uniform Deposition of through-hole by Pulse Electroplating in Acidic Copper Plating Bath

The effect of the polyethylene glycol (PEG) molecular weight upon the uniformity of through- hole deposition was studied in acidic copper bath.The results showed that the uniformity of through-hole increases with the increase of the molecular weight of PEG,and the uniformity of through-hole can reach more than 90% when the molecular weight of PEG is 8 000 or 12 000.The effect of bis (3-sulfopropyl) disulfide (SPS) concentration and agitation rate upon the uniformity of through-hole deposition were also studied.When the agitation rate was 700 r/min and the concentration of SPS is in the range of 4.0 to 6. 0mg/L,a uniform copper conducting layer could be obtained.