Patent ID: 8349714

Claim:
A method of crystallizing a semiconductor film, comprising the steps of: forming a cap film over an amorphous semiconductor film, wherein the cap film is an insulting film; and irradiating the amorphous semiconductor film with a linear laser beam through the cap film and completely melting the amorphous semiconductor film to form a crystalline semiconductor film comprising a plurality of crystal grains and align crystal plane orientations of the plurality of crystal grains to each other, while scanning the linear laser beam, wherein a width of the linear laser beam on a surface which is irradiated in a direction parallel to a scanning direction of the linear laser beam is equal to or less than a width of one of the plurality of crystal grains of the crystalline semiconductor film in a direction perpendicular to the scanning direction of the linear laser beam, and wherein a thickness of the cap film is larger than or equal to 200 nm and smaller than or equal to 600 nm.