Laser annealing device, laser annealing method, and active matrix substrate production method

A laser annealing method of sequentially converging a plurality of laser beams in a plurality of regions of an amorphous silicon film to form a plurality of crystalline silicon islands arranged in M rows and N columns, the method comprising:

• step A:
• a step of providing:
• a stage having a bed plane for receiving a substrate;
• and a laser irradiation device to emit a plurality of laser beams toward the bed plane to form an irradiation region on the bed plane, the laser irradiation device including a laser device to emit a laser beam and a convergence unit that includes a microlens array having a plurality of microlenses arranged in m rows and n columns and a mask having a plurality of apertures disposed respectively for the plurality of microlenses;
• step B1:
• a step of placing on the bed plane a substrate having an amorphous silicon film on a surface thereof;
• step C1:
• a step of employing the laser irradiation device to form, as the plurality of laser beams, p rows and q columns or t rows and q columns of laser beams by using p rows and q columns (p≤m and q≤n) or t rows and q columns (t<p) of microlenses among the plurality of microlenses arranged in the m rows and the n columns, and to form respective convergence points of the plurality of laser beams in the plurality of regions of the amorphous silicon film;
• and
• step C2:
• a step of, after step C1, causing the substrate to make a relative movement with respect to the irradiation region by one pitch along a column direction, wherein,
• the method comprises step D including a sequence of performing step C1 followed by step C2, and thereafter step C1, wherein step D forms a respectively corresponding convergence point p times in each of the plurality of regions to become the plurality of crystalline silicon islands arranged in M rows and N columns, and the method performs, before having formed convergence points of the plurality of laser beams in all regions of the M rows and the q columns,
• at least one instance of step C3:
• a step of, after step C1, causing a set of p microlenses to be used in forming p instances of convergence points in one of M regions belonging in one column of the plurality of regions to differ, by at least one microlens, from a set of p microlenses having been used in forming p instances of convergence points in another of the M regions.