Behavior of vacancies in EP-Cu films by positron-annihilation lifetime spectroscopy and its impact on SIV phenomena

The behavior of vacancies in electroplated-Cu films has been characterized by a positron-annihilation lifetime spectroscopy (PALS) method correlated with stress-induced voiding (SIV) phenomena. Positron lifetime showed inverse correlation with sheet resistance, and Cu films plated with lower plating currents showed less lifetime (/spl tau/) and intensity (I) of long-lifetime components than those plated with higher currents with less SIV failures.