Local and global stress distributions in BEOL metallization

Abstract

Design of reliable thin film metallization is a complex problem that requires information about local parameters such as composition, microstructure, residual and loading stresses, etc. On the other hand, such information has been traditionally obtained using techniques that have sampling volumes that are appreciably larger than the BEOL dimensions currently in use. In this article, the x-ray residual stress analysis technique and its extensions to micro-domain measurements are reviewed. These concepts are then applied to strain data from in-situ x-ray measurements, obtained in real-time from Al metallization lines subjected to thermal stressing and electromigration.