Hardness reduction of Au bumps for tab interconnections

Abstract
For Tape Automated Bonding (TAB) bumps are used for interconnecting the bondpads to the flying leads on a foil carrier. A sputtered barrier layer of TiW is present between the Al bondpads and the straight wall gold bumps, The electroplating process for bump deposition and the inner lead banding of the bumps is described for both Sulphitic and cyanic based gold baths. The hardness of the different deposited bumps is also measured after annealing. Auger Electron Spectroscopy was performed to study the diffusion through the TiW barrier layer, Visual inspection of the TiW barrier layer showed the relationship between bump hardness and the inner lead bonding conditions. The goal of this study is to acquire information on the influence of the hardness on the inner lead bonding process. The results presented so far are part of a larger TAB study, in which the hardness is only one of the parameters.

This publication has 5 references indexed in Scilit: