Polycrystalline film, method for forming polycrystalline film, laser crystallization device and semiconductor device

A method for forming a polycrystalline film by directing laser through a mask to irradiate an amorphous film to leave a large number of evenly distributed crystal grains lining up in parallel lines extending along the surface of the film, the method comprising:

• providing a mask configured to modulate that portion of the laser which is directed therethrough to evenly distributed seed crystal generating regions set beforehand on an amorphous film to have an attenuated intensity;
• allowing the amorphous film to crystalize using the seed crystal generating regions as seed crystals, and
• leaving a no-lateral-growth region left at each of locations exposed to both ends of a grain interface, which serves as a partition between the neighboring two crystal grains, in a pattern that exposes the laterally crystallized film after lateral crystal growth, where:
• one of the both ends of the grain interface is separated from the other in a direction along the surface of the film.

A laser crystallization device, comprising:

• a laser source for generating laser;
• and
• a mask configured to modulate the laser directed therethrough to the surface of an amorphous film,
• wherein
• the mask is configured to modulate that portion of the laser which is directed therethrough to evenly distributed seed crystal generating regions set beforehand on an amorphous film to have an attenuated intensity;
• the laser with which a portion of the amorphous film adjacent to at least one of the seed crystal generation regions is irradiated has an intensity that is sufficient to melt through the entire thickness of the irradiated portion;
• the irradiated portion of the amorphous film laterally crystalizes using the seed crystal generating regions as seed crystals upon cooling, and
• the mask is configured to leave a no-lateral-growth region left at each of locations exposed to both ends of a grain interface, which serves as a partition between the neighboring two crystal grains, in a pattern that exposes the laterally crystallized film after lateral crystal growth, where:
• one of the both ends of the grain interface is separated from the other in a direction along the surface of the film.