Crystallization apparatus, crystallization method, and phase shift mask and filter for use in these apparatus and method

A crystallization method which illuminates a phase shift mask, and irradiates a polycrystal semiconductor film or an amorphous semiconductor film with a light ray having a light intensity distribution with an inverse peak pattern that a light intensity is minimum in an area corresponding to a phase shift portion of the phase shift mask, thereby generating a crystallized semiconductor film, comprising:

• arranging an image forming optical system in a light path between the polycrystal semiconductor film or the amorphous semiconductor film and the phase shift mask;
• setting an image side numerical aperture of the image forming optical system to a value required to generate the light intensity distribution with the inverse peak pattern;
• setting the polycrystal semiconductor film or the amorphous semiconductor film to a position which is optically conjugate with the phase shift mask through the image forming optical system;
• and
• using, as the phase shift mask, a phase shift mask which has a boundary area extending along a first direction across the phase shift mask, and a first area and a second area which are arranged on opposite sides of the boundary area along a second direction intersecting the first direction, and the first and second areas having a predetermined phase difference therebetween, the boundary area having a phase distribution which varies from a phase of the first area to a phase of the second area along the second direction.