Mechanism for Cu void defect on various electroplated film conditions

This study observes that copper (Cu) films deposited by high current densities or in an aged electrolyte easily generate void defects after chemical mechanical polishing (CMP). The (111)/(200) ratio and the impurity amount of an electroplated Cu film are found to have strong correlation with the formation of void defects. Furthermore, pulse-reverse waveform plating following direct current plating is used for the deposition of partial Cu films that will be exposed after Cu CMP. This new scheme produces a void-less Cu surface after CMP.