Electromigration testing on via line structures with a SWEAT method in comparison to standard package level tests

Two electromigration test methods are compared with the aim to find out if highly accelerated tests can be used to quantify the reliability of metallization. Experimental results show a good correlation between wafer level (WL) SWEAT and conventional standard package level (PL) tests on via terminated structures. Similar t_50N values are obtained extrapolating the data from both tests to norm conditions. Failure analysis show the same failure mechanism for both tests. We found a difference in current density exponent, which can partly be explained with an error in the temperature determination of the failed metal line. As a consequence the SWEAT method can not only be used for process monitoring but also to quantify the reliability of metallization. However the difference in current density exponent needs further investigation