Mikroabscheidung hochreiner Pb/Sn-Legierungen

Precision plating for flip chip attachment

: Gemmler, A.; Leonhard, W.; Richter, H.; Rueß, K.

Abstract
Prerequisite for flip chip attachement are bumps, which have to be placed on one of the partners to be joined. For silicon semiconductors bumping is done normally on the ICs at wafer scale. Bumping can be performed by micro plating of vacuum deposition techniques, also mechanical methods are well known. Within this work a bumping process based on tin/lead alloy plating is reported. The alloy plating process depending on the type of electrolyte and the process parameters is discussed. Methods for bump characterisation and quality assurance are reported as an important part of the bumping process.