Cobalt (Co) can replace Tantalum (Ta) as the barrier layer of copper (Cu) interconnection structure because of its low resistivity,good thermal stability and better adhesion to Cu.With the feature size decreased to 10 nm and less,Co will replace Cu as a new interconnect metal material,because of its good electromigration resistance and the ability to achieve void free filling on a very thin barrier layer,which has shown great potential for application.However,due to the strong reaction activity of Co and the difference of corrosion potential between different metal materials,pitting corrosion and galvanic corrosion defects are easy to form in the process of Cobalt CMP,which seriously affects the performance of the devices.The research status of the generation and control of surface defects in cobalt CMP process in recent years was comprehensively analyzed.The action mechanism of complexing agent and corrosion inhibitor in polishing solution was emphatically described.It was pointed out that under alkaline environment,the occurrence of pitting defects can be effectively controlled by selecting appropriate corrosion inhibitors and complexing agents,as well as by using the synergistic effect of different corrosion inhibitors.It was also pointed out that quantum chemistry can qualitatively and quantitatively analyze the synergistic mechanism of various reagents in the polishing solution from the molecular level,providing theoretical support for the design of polishing solution.