| 摘要 |
<p>A chromeless photomask includes a main pattern portion and a complementary pattern portion formed in the surface of the transparent mask substrate adjacent to an outer peripheral edge of the main pattern portion. The main and complementary pattern portions are each formed by recessing a surface of a transparent mask substrate to produce respective protrusions and recesses that induce a phase difference of 180 degrees in light rays passing therethrough. The complementary pattern portion is designed to produce interference that prevents distortion in the photoresist pattern formed at a region by and corresponding to the edge of the main pattern portion of the photomask. Accordingly, the present invention provides for a relatively large secondary mask alignment margin.</p> |
