Corrosion inhibitors for Cu chemical mechanical planarization (CMP)

Chemical mechanical planarization (CMP) is one of the key technologies in integrated circuit manufacturing. Copper interconnect CMP usually includes three steps: the first step is to remove bulk copper; the second step is to remove copper residue and terminate in the barrier layer; the third step is to remove the barrier layer and part of low-k dielectric. Since the integrated circuit entered the 20-14 nm process node, the polishing process of copper film has been compressed into one step and its quality directly affects the subsequent effects of barrier layer CMP and post CMP cleaning. H2O2 is generally used as an oxidant in copper CMP slurry. It can form an oxide passivation layer (CuO, Cu2O) on the copper surface, but the oxide passivation layer is discontinuous and porous. It is necessary to use additional corrosion inhibitors to reduce copper corrosion. Corrosion inhibitors can protect the copper surface and reduce chemical dissolution in the concave area, improve the removal rate selectivity of the convex and concave areas to achieve global planarization. In order to obtain better copper surface quality, researchers continue to explore new green corrosion inhibitors for copper CMP. In this chapter, the selection and the action mechanism of corrosion inhibitor, and the synergistic effects of inhibitors and other reactants for copper CMP are discussed.