New mechanism of contact electromigration

The reliability problems in a device have become more important as the chip size gets smaller. To improve the reliability, the main failure mechanism should be verified. However, the EM-induced damage at a contact or via hole has been usually ignored while the metal line failure has been strongly studied by many researchers. In this work, the electromigration (EM) mechanism at the submicron size of contact hole are presented with respect to type of dopants and to use of the barrier metal using AES, SEM, FIB micrographs, and EM measurement. One of the interesting results is void formation by Si atom migration to the metal line on Si substrate, instead of Al atom migration.