Ion implantation, one of the semiconductor processes, uses implanters such as Axcelis batch tool which shows what is called cone effects, a variation of ion beam incident angle on each beam-scanned wafer position because of the characteristics of implanted disk. In this paper, we will analyze theoretically the method of minimizing the incident angle variation, which is aroused by cone angle effect, by setting 3 appropriate angle values without additional control units and demonstrate it with tests.