Leveler is one of the crucial factors to fabricate electroplated Cu with excellent electrical property in advanced interconnect metallization. Little attention has been paid on the effects of leveler on the electrical resistance of electroplated Cu during self-annealing. In this study, the impacts of three different levelers on the sheet resistance of the electrochemical deposited Cu films are studied in terms of microstructure, impurity and electrochemical behavior. Three levelers show differences in inhibition ability on Cu deposition and levels of impurities introduced into Cu films, the former influences the original crystal grain size. The driving force originated from grain boundaries and hinder effect of impurities are two opposite factors which work competitively for grain growth. This study shows the direct evidence on the impacts of the two opposite factors on the resistance performance of deposited Cu films during self-annealing. We find that the leveler with the strongest inhibitory ability and a reasonable level of introduced impurities shows the largest resistance drop during recrystallization process, indicating the considerable improved conductivity. We believe this work will provide a scientific basis for the selection of levelers to obtain the Cu films with excellent electrical property and microstructure in electronic industrial applications. (C) 2019 The Electrochemical Society.