Method and apparatus for inspecting a mura defect, and method of manufacturing a photomask

An apparatus for inspecting a defect occurring in a repetitive pattern on a member to be inspected, the repetitive pattern having a plurality of unit patterns that are arranged in a regularity, the defect being that occurred in a plurality of said unit patterns in another regularity, the apparatus comprising:

• a detector for detecting the defect occurring in the repetitive pattern of the member to be inspected for producing defect detection data;
• and
• an evaluating unit for evaluating the defect by comparing the defect detection data with pseudo mura defect detection data;
• wherein the detector comprises a light source for irradiating a light onto the repetitive pattern to generate diffraction light at an edge portion of the repetitive pattern, and a light receiving device for receiving the diffraction light to produce defect detection data;
• said evaluating unit comprises a memory unit to store the pseudo mura defect detection data;
• and
• said pseudo mura defect detection data is prepared by subjecting a predetermined repetitive pattern having pseudo mura defects to said light irradiation to receive the diffraction light generated at an edge portion of the predetermined repetitive pattern, said pseudo mura defect data containing defect data of a plurality types of pseudo mura defects each with plurality of defect intensities.

A method for manufacturing a photomask comprising:

• forming a repetitive pattern containing a plurality of a unit patterns being arranged in a regularity,
• wherein the method further comprises a defect inspection, said defect inspection comprising:
• detecting the defect occurring in the repetitive pattern of the photomask to be inspected to produce defect detection data;
• evaluating the defect detection data by comparing with pseudo mura defect detection data;
• and
• determining whether the repetitive pattern is formed as satisfactory by the evaluation;
• wherein said defect detection is carried out by irradiating a light onto the repetitive pattern to generate diffraction light at an edge portion of the repetitive pattern, and receiving the diffraction light to produce defect detection data;
• and
• said pseudo mura defect detection data is produced by subjecting a predetermined repetitive pattern having pseudo mura defects to said light irradiation to receive the diffraction light generated at an edge portion of the predetermined repetitive pattern, said pseudo mura defect data containing defect data of a plurality types of pseudo mura defects each with a plurality of defect intensities.