| 摘要 |
PROBLEM TO BE SOLVED: To permit measurements in two directions of X and Y in one detection optical system while having a simple structure, and permit one of diffracted light rays in the two directions to be reflected and the other to be transmitted, by arranging a beam splitter which is partially provided with a reflection coating in the vicinity of a lens surface of an alignment optical system. SOLUTION: In the projection aligner a beam splitter 13 is arranged, which is partially provided with a coating, on a lens surface or in the vicinity so as to reflect only reflected diffraction light from lattice marks GWX which are arranged in a row in a direction of X. Through the operation of the beam splitter 13, the luminous flux of the reflected diffraction light from the lattice marks GWX arranged in a row in the direction X, and the luminous flux of the reflected diffraction light from lattice marks GWY arranged in a row in a direction of Y, are spatially isolated from each other. In this case, of course, the reflection may be made in the direction Y side, not limited to the direction X side. Thus, when using such a beam splitter which is partially provided with a reflection region, diffraction light in the two directions can be separated into reflection light for one direction and transmission light for the other direction without losing quantity of light. |
