Process of crystallizing semiconductor thin film and laser irradiation

A display comprising:

• a pair of substrates jointed to each other with a specific gap put therebetween;
• an electrooptic material held in the gap between said substrates;
• counter electrodes formed on one of said substrates;
• and
• pixel electrodes and thin film transistors for driving said pixel electrodes, which are formed on the other of said substrates, each of said thin film transistors including a semiconductor thin film and a gate electrode stacked on one surface of said semiconductor thin film via a gate insulating film;
• wherein said semiconductor thin film is obtained by forming amorphous silicon or poly-crystal silicon having a relatively small grain size on the other substrate, and irradiating the amorphous silicon or poly-crystal silicon having a relatively small grain size with the laser beam to crystallize the amorphous silicon or poly-crystal silicon having a relatively small grain size into poly-crystal silicon having a relatively large grain size;
• and
• the crystallization of said semiconductor thin film is performed by dividing the surface of the other substrate into a plurality of division regions, and shaping a laser beam to adjust an irradiation region of the laser beam such that one of the division regions is collectively irradiated with one shot of the laser beam;
• irradiating one of the division regions with the laser beam while optically modulating the intensity of the laser beam such that a cyclic light-and-dark pattern is projected on the irradiation region, and irradiating the same division region by at least one time after shifting the pattern such that the light and dark portions of the pattern after shifting are not overlapped to those of the pattern before shifting;
• and shifting the irradiation region of the laser beam to the next division region, and repeating the crystallization for the division region.

An organic EL display comprising:

• pixel electrodes containing luminous portions made from an organic EL material and thin film transistors for driving said pixel electrodes, which are formed on a substrate, each of said thin film transistors including a semiconductor thin film and a gate electrode stacked on one surface of said semiconductor thin film via a gate insulating film;
• wherein said semiconductor thin film is obtained by forming amorphous silicon or poly-crystal silicon having a relatively small grain size on the substrate, and irradiating the amorphous silicon or poly-crystal silicon having a relatively small grain size with the laser beam to crystallize the amorphous silicon or poly-crystal silicon having a relatively small grain size into poly-crystal silicon having a relatively large grain size;
• and
• the crystallization of said semiconductor thin film is performed by dividing the surface of the substrate into a plurality of division regions, and shaping a laser beam to adjust an irradiation region of the laser beam such that one of the division regions is collectively irradiated with one shot of the laser beam;
• irradiating one of the division regions with the laser beam while optically modulating the intensity of the laser beam such that a cyclic light-and-dark pattern is projected on the irradiation region, and irradiating the same division region by at least one time after shifting the pattern such that the light and dark portions of the pattern after shifting are not overlapped to those of the pattern before shifting;
• and shifting the irradiation region of the laser beam to the next division region, and repeating the crystallization for the division region.