Electroplating of Fe-Rich NiFe Alloys in Sub-50 nm Lines

The electroplating of NiFe alloys into 40 nm wide lines was studied using a variety of organic additives, including the ones used in literatures. In additive-free electrolytes, the presence of Fe was found to improve the super conformal plating into the trenches but defect free filling was not achieved. Potential transients during galvanostatic plating on rotating disk electrodes was used to characterize the additives. While some of the additives behave either as a suppressor or an accelerator, others showed both suppression and acceleration effects. Trench filling experiments were carried out to examine the filling performance of different additives and additive combinations. Center seams were always observed in the narrow trenches plated with single component additives for the conditions studied. However, faster suppression followed by slow relaxation was achieved for some combinations of the additives, resulting in defect free NiFe filling into the narrow lines.