Investigation of high reliability micro bump plating technique on tape carrier

This paper describes the continuous copper bump plating technique for TAB tape carriers. We investigated the copper plating bath, pre-treatment agents and the bath agitation method. For high speed and uniform plating, the selection of an appropriate copper plating bath is most important. Through our investigations, we found the most suitable bath for copper plating bumps, which obtained good appearance and high reliability bumps at 20 A/dm² or more. The tape carriers with copper plating bumps were applied to the new stacking board and the burn-in socket substrate for a 0.5 mm pitch BGA package. In both cases, it was confirmed that the tape with bumps had high reliability. Then, a continuous reel to reel plating machine for TAB tape carrier was designed and manufactured