| 摘要 |
An apparatus for evaluating a projection lens has a light source, a condenser lens, a half mirror, a mask having focus test patterns in each of which light-blocking members and light-transmitting portions are alternatingly arranged, and a reflecting member such as a wafer. A driving unit moves the half mirror along the surface of the mask to select a focus test pattern. A sensor detects the quantity of light reflected by the half mirror. The quantity of light transmitted through a focus test pattern and a projection lens to be evaluated, reflected by the reflecting member, and transmitted through the projection lens and the focus test pattern is detected using the half mirror and the sensor to determine the best focus position. The best focus position for each of the focus test patterns is determined to obtain a distribution of the best focus positions.
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