Auger electron spectroscopy studies on bondpad peeling failure in wafer fabrication

Abstract

In this paper, a case of bondpad peeling was investigated. EDX (energy-dispersive X-ray microanalysis) and AES (Auger electron spectroscopy) techniques were used to identify the possible root cause. Based on EDX and AES results, it is concluded that the bondpad peeling problem was due to significant carbon contamination on the peeled area of the bondpad, which might contribute to the bondpad peeling problem. EDX and AES results also confirmed the peeling occurred between the barrier metal and BPSG layers. The high C contamination had resulted in poor adhesion between the barrier metal and BPSG layers and resulted in the peeling problem. The high C contamination on the BPSG layer was introduced during the wafer fab process. It may be due to incomplete contact process resist strip or insufficient pre-clean before barrier metal deposition. In this paper, we also discuss the difference between EDX and AES analysis techniques and use the contamination diagram introduced by us.