A physical vapor deposition system includes a chamber, a cover plate, a pedestal, and a collimator. The cover plate is disposed on the chamber for holding a target. The pedestal is disposed in the chamber for supporting a wafer. The collimator is mounted between the cover plate and the pedestal. The collimator includes a plurality of sidewall sheets together forming a plurality of passages. At least one of the passages has an entrance and an exit opposite to the entrance. The entrance faces the cover plate, and the exit faces the pedestal. A thickness of one of the sidewall sheets at the entrance is thinner than a thickness of the sidewall sheet at the exit.