Impurity diffusion behavior study of electroplated copper films annealed by linear shaping laser mobile scanning system

Abstract

Impurities due to additives in electroplated copper interconnects diffuse during grain growth. High-resolution electron backscatter diffraction and TOF-SIMS (Time-of-flight secondary ion mass spectrometer) results reveal that the electroplated copper films after laser annealing by linear shaping laser mobile scanning system (LALS) have higher recrystallization fraction and less impurity content than traditional thermal annealing. Impurity diffusion behavior and grain boundary migration are inseparable. The effect of LALS on the impurity diffusion of electroplated Cu films is the result of the introduced local temperature gradient, which works collaboratively on the thermodynamics and kinetics of grain boundary migration. And the amount of impurity diffusion is related to the proportion of different species of impurities. The findings are meaningful for the metallization of electroplated copper interconnects.