Study of the additives influence in the CMP slurry for the surfaces planarisation covered by selective transfer

Abstract

Chemical mechanical planarisation (CMP) is the only effective technique for obtaining surfaces with higher resolution and flatness, by removing the metal excess obtained in the selective-transfer process. The CMP process of the selective-layer assumes layer surface oxidation, protection its, and passivation layer removal from the tops of the protrusions by abrasive particles mechanical action. The selective-layer slurry consists of hydrogen peroxide (H2O2) as an oxidiser, organic acids as complexing and etching agents, benzotriazole (BTA) as a corrosion inhibitor and silica (SiO2) particles as abrasive. To a higher removal rate and better slurry stability was used the citric acid, and BTA controlled adding in slurry could change the removal and etching rate of the selective-layer. This paper analyses the additives effect in CMP slurry on the polishing of covered surfaces through selective-transfer, considering removal and etching rates, as well as the slurry behaviour with different types and concentrations of additives, in various proportions.