Effect of Non-Ionic Surfactant on Copper Dishing and Dielectric Erosion Correction in Alkaline Barrier CMP Solution Free of Inhibitors

Cu dishing and dielectric erosion are usually generated at different pattern densities and line widths as a result of mechanical and chemical effects from slurry during the copper interconnections CMP process. The effect of non-ionic surfactant on Cu dishing and dielectric erosion correction in alkaline barrier CMP slurries free of inhibitors such as benzotriazole (BTA) was mainly investigated in this paper. The results of electrochemical, static etch rate and polishing experiments demonstrated that the non-ionic surfactant could inhibit the copper by adsorption, but did not aggravate the corrosion of copper and had little influence on material removal rate (MRR) selectivity among copper, tantalum and oxide. The correction value of Cu dishing and dielectric erosion increased remarkably and then maintained almost the same value as a function of non-ionic surfactant, indicating that the non-ionic surfactant had an ability to reduce Cu dishing and dielectric erosion. Finally, the adsorption mechanism of non-ionic surfactant was discussed. (C) 2017 The Electrochemical Society. All rights reserved.