Patent ID: 7205033

Claim:
A method for forming a polycrystalline silicon film of a polycrystalline silicon thin film transistor, the method comprising a step of crystallizing an amorphous silicon film deposited on a glass substrate by irradiating a laser beam onto the amorphous silicon film using a mask pattern, wherein the glass substrate is horizontally moved by a predetermined distance unit corresponding to a translation distance of the mask pattern when the laser beam is irradiated onto the amorphous silicon film through a mask having the mask pattern, thereby growing grains in a circular shape, and wherein the mask pattern is divided into three regions having lengths identical to each other, each region includes a plurality of hexagonal unit cells having six triangle areas, two opposite triangle areas of each hexagonal unit cell provide a transmission section, remaining four triangle areas of each hexagonal unit cell provide a non-transmission section, and positions of transmission sections formed in one region are different from positions of transmission sections formed in other regions.