Method of crystallizing amorphous silicon using a mask

A sequential lateral solidification mask, comprising:

• a first region having a plurality of first stripes separated by first slits;
• a second region having a plurality of second stripes separated by second slits, wherein the plurality of second stripes are perpendicular to the plurality of first stripes;
• a third region having a plurality of third stripes separated by third slits, wherein the third stripes are parallel to the first stripes;
• and
• a fourth region having a plurality of fourth stripes separated by fourth slits, wherein the fourth stripes are parallel to the second stripes.

A method of crystallizing a silicon film using sequential lateral solidification through a mask having a first region with a plurality of first stripes and first slits, a second region with a plurality of second stripes and second slits, wherein the plurality of second stripes are perpendicular to the plurality of first stripes, a third region with a plurality of third stripes and third slits, wherein the third stripes are parallel with the first stripes, and a fourth region with a plurality of fourth stripes and fourth slits, wherein the fourth stripes are parallel with the second stripes, the method comprising:

• setting the mask over a substrate having a silicon film;
• applying a laser beam to the silicon film through the mask such that portions that corresponds to the first, second, third, and fourth slits are crystallized;
• moving the silicon film relative to the mask by a quarter width of the mask;
• and repeatedly applying the laser beam to the silicon film after moving the substrate by quarter widths of the mask.