Manufacturing method of semiconductor device

A manufacturing method of a semiconductor device with improved operating characteristics and reliability is provided. An amorphous semiconductor film is formed over a substrate, doped with a metal element promoting crystallization, and crystallized by first heat treatment to form a crystalline semiconductor film; a first oxide film formed over the crystalline semiconductor film is removed and a second oxide film is formed; the crystalline semiconductor film having the second oxide film formed thereover is irradiated with first laser light; a semiconductor film containing a rare gas element is formed over the second oxide film; the metal element contained in the crystalline semiconductor film is gettered to the semiconductor film containing a rare gas element by second heat treatment; the semiconductor film containing a rare gas element and the second oxide film are removed; and the crystalline semiconductor film is irradiated with second laser light in an atmosphere containing oxygen.