Investigation of the palladium distribution in the intermetallic phase region of Au-Al wire bond interconnects

Palladium alloyed gold wire was used to form wire bond interconnects on aluminum metallization. By isothermal annealing of wire bond samples the formation of intermetallic Au-Al phases was stimulated. Compared to pure gold wire the IMP growth in the alloyed one is retarded. Comparative EBSD investigations of the phase regions exhibited slower growth rates. By STEM-EDS measurements compounds with higher Pd content could be revealed in the IMP.