Patent ID: 6949419

Claim:
A method for manufacturing an image display device driven by thin film transistors of a polycrystalline silicon film formed on a substrate, comprising: a step of depositing an amorphous silicon film on said substrate; a first laser irradiation step of scanning first laser beam irradiation relative to the substrate in a horizontal or vertical first scanning direction of a surface of the substrate, so as to irradiate a first region on the substrate without irradiating a second region thereon; a second laser irradiation step of scanning second laser beam irradiation relative to the substrate in a second scanning direction perpendicular to said first scanning direction, so as to irradiate said second region without irradiating said first region; and a step of forming portions of the thin film transistors in said polycrystalline silicon film, wherein a portion of the amorphous silicon film in said first region is crystallized to form a portion of said polycrystalline silicon film in said first laser irradiation step, and a portion of the amphorus silicon film in said second region is crystallized to form another portion of said polycrystalline silicon film in said second laser irradiation step, and wherein of a plurality of blocks aligned in one of the horizontal and vertical directions, at least one block includes thin film transistors of which current flows substantially in said horizontal direction and at least one block includes thin film transistors of which current flows substantially in said vertical direction.