Amino acids as complexing agents in chemical-mechanical planarization of copper

This study explains the relative importance of the *OH radical in the presence of other additives in hydrogen peroxide based slurries during chemical-mechanical planarization of copper. For this purpose, we investigated the effects of three different amino acids, that is, glycine, serine, and cysteine, in the presence of H2O2 on the dissolution of copper coupons and on the polishing of copper disks with well-dispersed slurries of fumed silica particles over the pH range 2.0 and 8.0. While these amino acids produced different amounts of *OH, the polish rates did not depend on the concentration of this radical alone but were influenced by other parameters such as the pH of the slurries and the specific interactions of the amino acids with other components of the slurry.