The Influence of Leveler on the Impurity Behavior of Electroplated Cu Films During Laser Annealing

Abstract

Leveler is one of the key factors for the fabrication of electroplated Cu with superior electrical properties in Cu interconnect metallization. Rarely notice has been paid on the influence of leveler on the impurity behavior of electroplated Cu during recrystallization. In this study, the impacts of five different levelers on the impurity behavior during recrystallization of the electrochemical deposited Cu films are studied in terms of microstructure and electrochemical behavior. Five levelers perform differences in molecular types and inhibition ability on Cu deposition. The former will affect the initial impurity content of the original crystal, while the latter is directly related to the amount of impurity diffusion during recrystallization. This study shows the direct evidence that two factors affect the impurity behavior of the electroplated Cu films during laser annealing and thus affect the resistance performance. We find that the films obtained by using leveler that has a reasonable inhibitory ability and incorporates the lowest initial impurity content shows the largest resistance drop during recrystallization. We believe the findings are meaningful for the selection of levelers to improve electrical property in the metallization of electroplated copper interconnects.