Self-annealing of electrochemically deposited copper films in advanced interconnect applications

Abstract

This paper describes the phenomenon of self-annealing of electrochemically deposited copper films. Sheet resistance was shown to decrease by approximately 20% within tens of hours after deposition at room temperature. At the same time, tensile film stress increased and X-ray diffraction results indicate a very large increase in the degree of film (111) texture, and/or grain growth. This annealing effect has an activation energy of approximately 1.1 eV, indicating that the time dependence on temperature is very strong.