Patent ID: 6764794
Filing Date: 2004-07-20
Classification: G03F,G06K

Abstract:
A photomask for focus monitoring used for focus monitoring that measures the position of an exposed surface in an optical system in order to adjust the focus of an optical image on the exposed surface at the time of pattern exposure, comprising:a substrate that allows the exposure light to pass through and unit mask structures for focus monitoring, wherein said unit mask structure for focus monitoring has: two patterns for position measurement for measuring the mutual positional relationship formed on the surface of said substrate; and a light blocking film that is formed on the rear surface of said substrate and has a rear surface pattern for substantially differentiating the incident directions of the exposure light that enters said two patterns for position measurement, and wherein L/&lgr; is 10, or greater, wherein the dimension of said rear surface pattern is L and the wavelength of the exposure light is &lgr;.