Abstract: A crystallization apparatus includes a mask and an illumination system which illuminates the mask with a light beam, the light beam from the illumination system becoming a light beam having a light intensity distribution with an inverse peak pattern when transmitted through the mask, and irradiating a polycrystal semiconductor film or an amorphous semiconductor film, thereby generating a crystallized semiconductor film. The mask includes a light absorption layer having light absorption characteristics according to the light intensity distribution with the inverse peak pattern.