Effect of Corrosion Inhibitor BTA on Silica Particles and their Adsorption on Copper Surface in Copper Interconnection CMP

Abstract

In the process of chemical mechanical polishing (CMP) of multilayer copper wiring of integrated circuits, benzotriazole (BTA) as corrosion inhibitors and silica particles as abrasives are important components of polishing slurry. At the same time, they are also the main objects of post CMP cleaning. Under alkaline conditions (pH 10), the addition of BTA will affect the stability of silica particles, such as particle size and zeta potential, so as to affect the adsorption of particles on the copper surface. The effects of different concentrations of BTA on the adsorption of silica particles on copper surface were characterized by scanning electron microscopy (SEM), and the corresponding adsorption mechanism was also analyzed by X-ray photoelectron spectroscopy (XPS). The adsorption energies of BTA molecule and SiO2 molecule on copper surface were calculated by molecular dynamics simulation. The results show that 3 mM BTA reduces the adsorption capacity of SiO2 particles, and increasing the concentration of BTA will increase the adsorption capacity of SiO2 particles on the copper surface.