Resistance Measurements and Simultaneous AFM Imaging on Electrodeposited Copper Films during Room Temperature Aging

Abstract

Electrical resistance measurements of 30 - 120 nm electrodeposited copper films were made simultaneously with atomic force microscopy (AFM) imaging. Resistance decreases relatively rapidly immediately after deposition. It reaches a minimum, typically after less than an hour, and then increases to a maximum and subsequently decays. AFM showed the formation of smaller surface features during the period of increase in resistance. Subsequent to the maximum in resistance, features increased in size, consistent with recrystallization and grain growth. It is speculated that the increase in resistance may to be related to structural changes in the film and that the early decrease in resistance may reflect a contribution from the out- diffusion of excess vacancies.