Addition of PEG-Thiol to Cu Electroless Plating Bath for Realizing Perfect Conformal Deposition in Through-Si Via Holes for 3-D Integration

摘要

In this study, we succeeded in forming a near-conformal Cu seed layer in TSVs with high aspect ratio (4 and 10) using electroless plating with the addition of PEG-thiol. It turned out that the addition of PEG-thiol to the Cu electroless plating bath has an inhibitional effect. By the combination of electroless Cu plating and subsequent Cu electroplating is very effective to completely fill TSVs with Cu. Thus this technology is a candidate for practical application of Cu seed layers.