Photomask for measuring lens aberration, method of manufacturing the same, and method of measuring lens aberration

摘要

A photomask is useful in measuring the aberration of an optical lens. The photomask includes a transparent substrate, a first opaque pattern formed on a first surface of the transparent substrate and defining a plurality of apertures that expose the first surface, and a second opaque pattern formed on the second surface of the transparent substrate. The photomask is placed in an exposure apparatus between a light source of the exposure apparatus and an optical lens whose aberration is to be measured. A photoresist layer on a wafer is exposed through the photomask and the pupil of the optical lens to form a first pattern on the wafer corresponding to the second opaque pattern of the photomask. The aberration of the pupil of the optical lens is evaluated based on the relative location at which the first pattern is formed on the wafer. Because the optical aperture is formed on the photomask along with the pattern whose image is to be transferred to the photoresist layer, the alignment between the optical aperture and the photomask pattern is assured.