Study on chemical effects of H2O2 and glycine in the Copper CMP process using ReaxFF MD

ReaxFF MD simulation was employed to simulate the chemical mechanical polishing (CMP) process of copper in four different polishing slurries (pure H2O, aqueous H2O2, aqueous glycine and a mixture aqueous H2O2 and glycine) in order to investigate the microchemistry mechanism during the copper CMP process. Results indicate that the increment of H2O2 concentration can inhibit the adsorption of H2O on the copper surface and promote the dissociation of H2O. After adding glycine to polishing slurry, the adsorption of H2O on the copper surface is also inhibited and there are copper complex (CueC(2)H(5)O(2)N) forming on the copper surface. Copper atoms on the topmost surface are weaken under the action of H2O2 and glycine, which is beneficial to atoms removal. The amount of copper atoms removed is the least in pure water and the most in a mixture of aqueous H2O2 and glycine during the copper CMP process. In addition, the amount of copper atoms removed increases first and then decreases with the increment of H2O2 concentration. This work shows atomic insights into copper atoms removal under the combination of chemical and mechanical effects, which provides an effective method to choose CMP slurry.