Mn-based (referred to simply as Mn in the following) barrier/Ru liner stack has been proposed to replace TaN/Ta barrier-liner in Cu interconnects for 7 nm and 5 nm technology nodes. During chemical mechanical planarization (CMP) of the associated Cu/Ru/Mn/SiCOH pattern structures, the usual galvanic corrosion and removal rate selectivity issues need to be resolved. In this study, we investigated the polishing and electrochemical behavior of Cu, Mn, Ru and SiCOH films on the relevant substrates in the alkaline region using silica dispersions containing potassium permanganate (KMnO 4 ), guanidine carbonate (GC) and benzotriazole (BTA) and identified compositions that address these challenges. An XPS study of the as-deposited and annealed Mn films confirmed the formation of amorphous manganese silicate (MnSi x O y ), a self-forming dielectric layer, at the Mn/SiCOH interface. A crosssectional TEM analysis of the polished Cu/Ru/Mn/SiCOH patterned wafers (32 nm half pitch Cu lines) with our candidate slurry showed excellent post-polish performance with no corrosion and no post-CMP loss of either Cu or the Mn barrier/Ru liner film. As the node sizes continue to diminish, the 5∼7 nm thick Ta/TaN barrier-liner will occupy a significant portion of the Cu trench resulting in higher effective resistance and increased resistance-capacitance delay.1 Also, with the even smaller feature sizes and high-aspect-ratio trenches of these nodes, deposition of a conformal Cu seed layer on the Ta liner is a major challenge with any discontinuities in it leading to voids in the copper fill and limiting the yield.1 Hence, it has become necessary to replace these Ta/TaN barrier-liner films with thinner and more functional candidate materials. One such candidate is a Mn/Mnbased film since it can form a very thin (∼1 nm) self-forming and excellent Cu diffusion barrier layer of amorphous manganese silicate (MnSi x O y ) at the Mn/low-k (black diamond or SiCOH with k = 2.9 or lower) 1-10 interface. However, this MnSi x O y layer is not conductive enough and requires a thin conductive liner for the deposition of a Cu seed layer. A ∼2 nm thick Ru film with a resistivity of ∼7 μ cm, much lower than that of Ta's ∼13 μ cm, has been proposed 10,11 as such a liner. As always, these film stacks need to be planarized and for effective planarization, as shown in Figure 1, the removal rate (RR) selectivities among the Cu, Ru, Mn and SiCOH or BD layers and the galvanic corrosion between Cu/Ru and Ru/Mn couples need to be controlled. With that goal in mind, we investigated the polishing and electrochemical behavior of the relevant Mn-based barrier/Ru liner stack using silica based dispersions and various additives. For convenience, in the following the Mn-based films will be addressed simply as Mn films.Cu and Ru polishing behavior 12-18 and related corrosion issues [19][20][21][22][23] for barrier applications have been studied by several authors. Among these, Amanapu et al. 18 showed that the underlying substrate can modify the crystalline orientation o...