US Patent 7217319 Crystallization apparatus and crystallization method

A crystallization apparatus includes an illumination system which illuminates a phase shifter having a phase shift portion, and irradiates a polycrystal semiconductor film or an amorphous semiconductor film with a light beam having a predetermined light intensity distribution in which a light intensity is minimum in a point area corresponding to the phase shift portion of the phase shifter, thereby forming a crystallized semiconductor film, the phase shifter has four or more even-numbered phase shift lines which intersect at a point constituting the phase shift portion. An area on one side and an area on the other side of each phase shift line have a phase difference of approximately 180 degrees.