Patent ID: 7507645

Claim:
A method of forming a polycrystalline semiconductor layer, comprising: forming a semiconductor layer of amorphous silicon on a substrate; forming a plurality of spot seeds in the semiconductor layer by irradiating a first laser beam through a crystallization mask, each of the plurality of spot seeds being equally spaced from one another and each having equal area, wherein each of the plurality of spot seeds includes polycrystalline silicon; and forming a polycrystalline silicon layer along an entire surface of the substrate by irradiating a second laser beam onto the semiconductor layer, wherein an area between adjacent spot seeds is entirely exposed to the second laser beam, wherein the first laser beam has an energy density to completely melt the entire semiconductor layer and the second laser beam has an energy density to melt most of the semiconductor layer, wherein the energy density of the first laser beam is larger than the energy density of the second laser beam.