The effect of oxidizer addition, namely, H2 O2, KIO3, and Fe (NO3) 3, on the galvanic behavior of the CuTa coupling in 0.01 M Na2 SO4 +1 wt % Al2 O3 base slurry was studied. Both open-circuit potentials of the uncoupled Cu and Ta as well as galvanic current of the CuTa were measured in static and under chemical mechanical polishing conditions to analyze the roles of these additives. The results showed that Fe (NO3) 3 was more effective than H2 O2 and KIO3 in promoting the passivation of Ta, which in turn caused the change of polarity between Cu and Ta. The effect of CuTa area ratio on the galvanic behavior of the coupling was also investigated. The results showed that in Fe (NO3) 3 -containing slurry, Ta was the anode with a CuTa area ratio of 5:1 but became the cathode with an area ratio of 1:1.
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