EXTRA-EM: extraction of temperature and resistance for acceleration of electromigration at wafer-level

A thermal model and a control algorithm are developed for rapid electromigration (EM), which extracts both temperature and resistance for acceleration (EXTRA) from a standard wafer-level electromigration acceleration test (SWEAT) test structure. SWEAT structure complexity makes determination of the temperature and resistance during the execution of stress very difficult. The originally developed SWEAT thermal model is inaccurate because it cannot separate temperature changes from EM voiding, and this adds variability to failure distributions. EXTRA uses heat flow characteristics from individual structure regions to provide (1) narrow region temperature separated from resistance changes due to voiding, (2) rapid stress convergence, (3) stress control without empirically derived software, and (4) overall reduced variability in failure distributions.<>