In the Cu metallization process, it is important to prevent corrosion and recession of metal lines resulting from chemical reactions during the chemical mechanical polishing (CMP) process. In this paper, 5-aminotetrazole (ATRA) is investigated as a corrosion inhibitor for Cu CMP. In the wet etch test, it was found that the etch rate of ATRA decreased with concentration. The potentiodynamic polarization test and chronoamperometry test results revealed that ATRA could inhibit the Cu surface against corrosion more effectively than benzotriazole (BTA) below 0.01 M. Fourier transform infrared and ultraviolet-visible analysis clearly demonstrated that ATRA dissociated more easily in all pH ranges and could be polymerized faster and more effectively than BTA. Therefore, both corrosion and recession could be considerably reduced after CMP by using slurry containing ATRA. Furthermore, from the results of defect review after CMP, it was found that defects such as slurry residue, pit corrosion, and particles were effectively prevented due to small molecular size and high solubility of ATRA.