EVALUATION METHOD OF INTERFACE STRENGTH BETWEEN THIN FILMS IN ADVANCED LSI

摘要

This paper aims to develop a method for evaluating the interface strength between thin films on a silicon substrate of LSI. Although several methods have been proposed, plastic deformation and fracture of thin metal film bring about ambiguity in the magnitude of the interface strength obtained. Especially, it is important to determine the criterion of delamination crack initiation from the edge where the stress concentrates due to the mismatch of elastic deformation. In this study, an evaluation method is proposed, and the validity is examined by experiments on Cu (conductor metal)/TaN (barrier metal) interface on a silicon substrate. The stress intensity at the delamination crack initiation is successfully analyzed by the boundary element method (BEM).