The corrosion phenomenon was found at the edge area of bond pad under OM images after dicing saw. Experiment showed that the corrosion was related with the feed speed of dicing saw. From SEM and OM results, there were some abnormal contaminations around the corrosive area. Auger and TEM with EDX system were used to characterize the corrosive region and the related Al pad corrosion mechanism was discussed. In this paper, Cu rich and O rich layers were identified by TEM and EDX, which could be induced by galvanic cell reaction.