Thin Film Cracking / Delamination Evaluation Using Assembly Test Chip

Abstract

We have utilized an Assembly Test Chip (ATC) to study die and packaging interaction during a new fab process development. This paper shows a case study of using ATC to evaluate 2 plastic-package specific failure mechanisms, Thin Film Cracking (TFC) and Thin Film Delamination (TFD). Special test structures have been designed and shown to be sensitive to TFC and TFD. Failures can be detected electrically by simple continuity test, as opposed to the conventional decap &visual technique. We find that Temperature Cycling induces TFC for large die size and Steam induces TFD for thin film stack. New process options have been developed in order to achieve optimum TFC and TFD performance, using the ATC.