SIZE AND VOLUME DISTRIBUTIONS OF THERMALLY-INDUCED STRESS VOIDS IN ALCU METALLIZATION

AlCu integrated circuit interconnect lines are stressed at 200 degrees C for a variable duration of time. The number of stress voids and the total void volume are measured, The number of voids saturates between 0.1 and 1 day of stress, and reaches a constant value. The total void volume continues to rise and saturates between 30 and 100 days of str ess at 200 degrees C. Measurements also show that the void volume and the penetration length of the voids into the lines have a log-normal d istribution. (C) 1996 American Institute of Physics.