Method for preparing polycrystalline silicon layer and light shield

It relates to a method of fabricating a polysilicon layer according to the present invention. First, a substrate and an amorphous silicon region is formed on the substrate, an amorphous silicon layer having a first region and a second amorphous silicon amorphous region. Next, there is provided a photomask, the photomask comprising a light-transmitting region and the transparent portion region, the light-transmitting region and the transparent portions respectively corresponding to the second region and the first amorphous silicon region amorphous region. Then, a photomask is irradiated with a laser light, the amorphous silicon region such that the first and the second amorphous silicon is fully melted region is preheated is fully melted and the first amorphous silicon region is crystallized into a first polycrystalline silicon layer. Then, moving the mask or the substrate, such that the light-transmissive region corresponding to the second amorphous silicon region is preheated. Subsequently, a photomask is irradiated with a laser light, such that the second amorphous silicon region is fully melted is preheated, and is fully molten second amorphous silicon region is crystallized into a second polycrystalline silicon layer.