Mask plate, exposure equipment and mask plate alignment method

The invention relates to the technical field of chip preparation and photoetching, in particular to a mask plate, exposure equipment and a mask plate alignment method. The mask plate comprises a substrate which is used as a supporting substrate of the mask plate; the alignment mark structure is arranged on the surface of the substrate, and the alignment mark structure comprises a phase modulator which is located in the center of the alignment mark structure and has a positive lens phase and a light-transmitting area located on the periphery of the phase modulator; wherein when the input light beam enters the alignment mark structure, an interference pattern is formed, and when the interference pattern is a symmetrical pattern, the input light beam is perpendicular to the mask plate, and alignment of the mask plate relative to the input light beam is achieved. The alignment mark structure is arranged on the mask plate, and alignment detection can be realized by judging whether interference patterns formed when