Thickness uniformity of diamond-like carbon (DLC) films formed on 5 in. Si wafers by a supermagnetron plasma chemical vapor deposition with applying a static magnetic field was evaluated as a function of radio-frequency (rf) phase difference (RFPD) between two synchronized rf powers (13.56 MHz) supplied to parallel electrodes. When RFPD was 0 degrees, the uniformity of DLC film formed on a lower electrode became poor (about +/-9%), and at RFPD of about 180 degrees, it became excellent (about +/-3%). Thickness distributions were measured as a function of upper-electrode rf power (UPRF) at lower-electrode rf power (LORF) of 400 W. When UPRF was 0 W (conventional magnetron plasma mode), linearly graded thickness distribution was observed along perpendicular direction to magnetic field lines. At UPRF of 100 W, almost uniform distribution of +/-2.9% was obtained, and an inverse thickness distribution to the distribution at UPRF of 0 W was observed at UPRF of 200 W, i.e., inverse magnetron plasma mode. Thickness uniformity also depended on electrode spacing, and good uniformity of +/-3% was obtained at a separation of 40-45 mm. By applying a rotating magnetic field, extremely good uniformity of +/-1.3% could be obtained.