Patent ID: 7357963
Filing Date: 2008-04-15
Classification: B23K,H01L

Abstract:
1. A method of crystallizing an amorphous silicon film using a sequential lateral solidification apparatus, which includes a laser generator generating and emitting a laser beam, an X-Y stage movable in two orthogonal axial directions, a mask arranged between the laser generator and the X-Y stage, the mask having a plurality of slits through which the laser beam passes, an objective lens arranged between the mask and the X-Y stage and the objective lens scaling down the laser beam, and a mask stage connected to the mask, the mask stage controlling fine movement of the mask, the method comprising: setting a substrate having an amorphous silicon film thereon upon the X-Y stage; irradiating the laser beam to the amorphous silicon film through the plurality of slits of the mask, thereby melting and crystallizing first portions of a block, wherein the mask defines a block in the amorphous silicon film and wherein the first portions are crystallized by sequential lateral solidification that grows grains along a first direction from interfaces between solid phase amorphous silicon and liquid phase silicon; stepping the mask in the first direction by several micrometers using the mask stage after completing the crystallization for the first portions; irradiating the laser beam to next portions of the block of the amorphous silicon film through the plurality of slits of the mask stepped, wherein the next portions of the block are adjacent to the first portions, and wherein the stepping of the mask in the first direction by the mask stage and the irradiation of the laser beam thereafter are repeated until a lateral grain growth stops in the block by a collision of laterally grown grains, thereby completing the crystallization within the block in the amorphous silicon film; stepping the X-Y stage block by block in the first direction to crystallize another block of the amorphous silicon film after completing the crystallization in the previous block; and repeatedly melting and crystallizing another block of the amorphous silicon film whenever the X-Y stage steps.