Mask for sequential lateral solidification and crystallization method using thereof

A method of forming a polycrystalline silicon layer from an amorphous silicon layer on a substrate, comprising:

• disposing a mask over the amorphous silicon layer, the mask having a plurality of transmissive regions, the plurality of transmissive regions being disposed in a stairstep arrangement spaced apart from each other in a first direction and a second direction substantially perpendicular from the first direction, each transmissive region having a central portion passing a substantially constant laser energy density along the first direction and first and second side portions that are adjacent to opposite ends of the central portion along the first direction, and wherein each of the side portions passes a decreasing laser energy density along the first direction away from the central portion;
• irradiating a laser beam onto the amorphous silicon layer a first time through the mask to form a plurality of first irradiated regions corresponding to the plurality of transmissive regions, each first irradiated region having a central portion, and first and second side portions that are adjacent to opposite ends of the central portion;
• moving the substrate and the mask relative to one another such that the first side portion of each transmissive region overlaps the central portion of each first irradiated region;
• and
• irradiating the laser beam onto the amorphous silicon layer a second time through the mask to form a plurality of second irradiated regions corresponding to the plurality of transmissive regions.

A method of forming a polycrystalline silicon layer from an amorphous silicon layer on a substrate, comprising:

• disposing a mask over the amorphous silicon layer, the mask having a plurality of transmissive regions, the plurality of transmissive regions being disposed in a stairstep arrangement spaced apart from each other in a first direction and a second direction substantially perpendicular from the first direction, each transmissive region having a laser energy density along the first direction that is substantially constant along the first direction that decreases gradually to a value where the amorphous silicon layer does not melt completely near ends of the transmissive region;
• irradiating a laser beam onto the amorphous silicon layer a first time through the mask to form a plurality of first irradiated regions corresponding to the plurality of transmissive regions, each first irradiated region having a completely melted portion and a portion that is not completely melted due to the laser energy density irradiating the amorphous silicon layer;
• moving the substrate and the mask relative to one another such that the first side portion of each transmissive region overlaps the central portion of each first irradiated region;
• and
• irradiating the laser beam onto the amorphous silicon layer a second time through the mask to form a plurality of second irradiated regions corresponding to the plurality of transmissive regions.