It is a problem to provide a semiconductor device production system using a laser crystallization method capable of preventing grain boundaries from forming in a TFT channel region and further preventing conspicuous lowering in TFT mobility due to grain boundaries, on-current decrease or off-current increase. An insulation film is formed on a substrate, and a semiconductor film is formed on the insulation film. Due to this, preferentially formed is a region in the semiconductor film to be concentratedly applied by stress during crystallization with laser light. Specifically, a stripe-formed or rectangular concavo-convex is formed on the semiconductor film. Continuous-oscillation laser light is irradiated along the striped concavo-convex or along a direction of a longer or shorter axis of rectangle.