Reliability of a semiconductor device is improved, and use efficiency of a sputtering apparatus is increased. When depositing thin films over a main surface of a semiconductor wafer using a magnetron sputtering apparatus in which a collimator is installed in a space between the semiconductor wafer and a target installed in a chamber, a region inner than a peripheral part of the collimator is made thinner than the peripheral part. Thus, it becomes possible to suppress deterioration in uniformity of the thin film in a wafer plane, which may occur as the integrated usage of the target increases.