| 摘要 |
PURPOSE:To reduce the number of alignment optical systems by automatically detecting positions of the (x) direction and (y) direction of each chip on a wafer by one alignment pattern and one alignment detection optical system. CONSTITUTION:Beam light emitted from an Ar laser 45 is reflected by a mirror section 37, and lights an alignment pattern 61 on a wafer 3 through a reduction projection lens 2. Reflected beams from the wafer 3 are reflected by the mirror section 37 on the lower surface of a reticle, and image-formed at a position 39 on just a half mirror 40 on the surface lower than the reticle only by the chromatic aberration section of the reduction projection lens 2 to the wavelength of the Ar laser 45. The image is reflected by a mirror 41, and formed at the front-side focal position 85 of a Fourier transformer lens 19 by a magnifying lens 47. The magnified image of the front-side focal position 85 is complex Fourier-transformed optical by the Fourier transformer lens 19, and complex amplitude distribution thereof is overlapped on an interference pattern 25 on an optical correlation filter 26, thus forming correlation. Complex amplitude distribution is complex Fourier inverse-transformed optically by a Fourier transform lens 28, and an optical peak is detected by a solid-state image pickup element 51. |
