Abstract
Ta is widely used as both a diffusion barrier layer and adhesion layer between Cu interconnects and dielectric materials. Because Ta has no catalytic activity on Cu electroless deposition, it needs an activation before the Cu electroless deposition. This study focused on the oxidation of several reducing agents on Pd particles formed on Ta surface. By an electrochemical analysis, it was observed that the higher Pd nuclei density showed the higher oxidation current, and the position of the peak current shifted more negatively with the higher Pd nuclei density. Using this electrochemical method, the optimization of Pd activation was achieved, and it was successful on the formation of thin Cu seed layer by Cu electroless deposition.