Study of Aluminum Pad Contamination Sources during Wafer Fabrication, Shipping, Storage and Assembly

In this paper, pad contamination sources were summarized and several cases were studied. The fluorine on bond pad was introduced through top metal etch/pad opening process per etch gases or shipping related issue. The higher carbon and oxygen on the abnormal pad were introduced during the process of backside grinding in case.1. The package paper during shipping caused the oxygen and kalium contamination on the abnormal pad in case 2. In case 3, the silicon dust on the abnormal pad formed during die sawing.