Abstract: To provide a continuous oscillation laser apparatus, and a manufacturing method of a semiconductor device using the continuous oscillation laser apparatus, which can enhance processing efficiency. A laser apparatus according to the present invention includes: a laser oscillation apparatus; a unit for rotating an object to be processed; a unit for moving the object to be processed toward a center of the rotation or toward an outside from the center; and an optical system for processing a laser light outputted from the laser oscillation apparatus and irradiating the processed laser light to a definite region in a moving range of the object to be processed, in which, while the object to be processed is rotated, the object to be processed is moved toward the center of the rotation or toward the outside from the center to move a position where the definite region and the object to be processed overlap.

Abstract: A technique for manufacturing TFTs having little dispersion in their electrical characteristics is provided. Contamination of a semiconductor film is reduced by performing oxidation processing having an organic matter removing effect, forming a clean oxide film, after removing a natural oxide film formed on a semiconductor film surface. TFTs having little dispersion in their electrical characteristics can be obtained by using the semiconductor film thus obtained in active layers of the TFTs, and the electrical properties can be improved. In addition, deterioration in productivity and throughput can be reduced to a minimum by using a semiconductor manufacturing apparatus of the present invention.