There is a lot of hydroxyl on the surface of nano SiO2 sol used as an abrasive in the chemical mechanical planarization(CMP) process, and the chemical reaction activity of the hydroxyl is very strong due to the nano effect.In addition to providing a mechanical polishing effect, SiO2 sol is also directly involved in the chemical reaction.The stability of SiO2 sol was characterized through particle size distribution, zeta potential, viscosity, surface charge and other parameters in order to ensure that the chemical reaction rate in the CMP process, and the surface state of the copper film after CMP was not affected by the SiO2 sol. Polarization curves and corrosion potential of different concentrations of SiO2 sol showed that trace SiO2 sol can effectively weaken the passivation film thickness. In other words, SiO2 sol accelerated the decomposition rate of passive film. It was confirmed that the SiO2 sol as reactant had been involved in the CMP process of copper film as reactant by the effect of trace SiO2 sol on the removal rate of copper film in the CMP process under different conditions. In the CMP process, a small amount of SiO2 sol can drastically alter the chemical reaction rate of the copper film, therefore, the possibility that Cu/SiO2 as a catalytic system catalytically accelerated the chemical reaction in the CMP process was proposed. According to the van’t Hoff isotherm formula and the characteristics of a catalyst which only changes the chemical reaction rate without changing the total reaction standard Gibbs free energy, factors affecting the Cu/SiO2 catalytic reaction were derived from the decomposition rate of Cu(OH)2 and the pH value of the system, and then it was concluded that the CuSiO3 as intermediates of Cu/SiO2 catalytic reaction accelerated the chemical reaction rate in the CMP process.It was confirmed that the Cu/SiO2 catalytic system generated the intermediate of the catalytic reaction(CuSiO3/in the CMP process through the removal rate of copper film, infrared spectrum and AFM diagrams in different pH conditions. Finally it is concluded that the SiO2 sol used in the experiment possesses stable performance; in the CMP process it is directly involved in the chemical reaction by creating the intermediate of the catalytic reaction(CuSiO3/ whose yield is proportional to the pH value, which accelerates the removal of copper film. There is a lot of hydroxyl on the surface of nano SiO2 sol used as an abrasive in the chemical mechanical planarization (CMP) process, and the chemical reaction activity of the hydroxyl is very strong due to the nano effect. Addition to providing a mechanical polishing effect, SiO2 sol is also directly involved in the chemical reaction. The stability of SiO2 sol was characterized through particle size distribution, zeta potential, viscosity, surface charge and other parameters in order to ensure that the chemical reaction rate in the CMP process, and the surface state of the copper film after CMP was not affected by the SiO2 sol. Polarization curves and corrosion potential of different concentrations of SiO2 sol showed that trace SiO2 sol can effectively weaken the passivation film thickness. decomposition rate of passive film. It was confirmed that the SiO2 sol as reactant had been involved in the CMP process of copper film as reactant by the e ffect of trace SiO2 sol on the removal rate of copper film in the CMP process under different conditions. In the CMP process, a small amount of SiO2 sol can drastically alter the chemical reaction rate of the copper film, therefore, the possibility that Cu / SiO2 as a catalyst system catalytically accelerated the chemical reaction in the chemical reaction rate without changing the total reaction standard Gibbs free energy, factors affecting the Cu / SiO2 catalytic reaction were derived from the decomposition rate of Cu (OH) 2 and the pH value of the system, and then it was concluded that the CuSiO3 as intermediates of Cu / SiO2 catalytic reaction accelerated the chemical reaction rate in the CMP process. It was confirmed that the Cu / SiO2 catalytic system generated the intermediate of the catalytic reaction (CuSiO3 / in the CMP process through the removal rate of coppit is said that the SiO2 sol used in the experiment possesses stable performance; in the CMP process it is directly involved in the chemical reaction by creating the intermediate of the catalytic reaction ( CuSiO3 / whose yield is proportional to the pH value, which accelerates the removal of copper film.