Patent ID: 7279372

Claim:
A manufacturing method of a semiconductor device provided with a thin film transistor over a substrate having an insulation surface, comprising: forming a non-monocrystal semiconductor over said substrate; forming a marker and an island-like semiconductor layer A, which is a specific area including an area to become an active layer of said thin film transistor, in said non-monocrystal semiconductor in accordance with a layout information of said thin film transistor; forming a crystallization area by irradiating a laser beam selectively to said island-like semiconductor layer A using said marker as a positional reference; and etching a periphery area of said island-like semiconductor layer A to form an island-like semiconductor layer B, which becomes an active layer area of said thin film transistor, wherein said laser beam is a laser beam of pulse oscillation, and attenuation area width from peak position of an optical power to a point where the power decreases to 50% is 10 μm or less.