A film forming system comprises a chamber, a stage, a holder, a cathode magnet, a shield, a first moving mechanism, and a second moving mechanism. The chamber provides a processing space. The stage is provided in the processing space and configured to support a substrate. The holder is configured to hold a target that is provided in the processing space. The cathode magnet is provided outside the chamber with respect to the target. The shield has a slit and is configured to block particles released from the target around the slit. The first moving mechanism is configured to move the shield between the stage and the target along a scanning direction substantially parallel to a surface of the substrate mounted on the stage. The second moving mechanism is configured to move the cathode magnet along the scanning direction.