contacting a polishing surface of a semiconductor substrate with a polishing pad attached to a turntable; and

dropping a CMP slurry onto the polishing pad to polish the polishing surface, the CMP slurry being selected from the group consisting of a first slurry and a second slurry, the first slurry comprising an abrasive grain, and a mixed surfactant comprising a first nonionic surfactant formed of a polyether type nonionic surfactant having an HLB value ranging from 3 to 9 at room temperature and a second nonionic surfactant formed of a polyether type nonionic surfactant having an HLB value ranging from 10 to 20 at room temperature, and the second slurry comprising an abrasive grain, and a mixed surfactant comprising a first nonionic surfactant having a clouding point ranging from 19 to 51° C. and a second nonionic surfactant having a clouding point of 55° C. or more.