| 摘要 |
PURPOSE:To improve accuracy in alignment, by correcting chromatic aberration yielded in a projection optical system, when a pattern having a lens effect is formed on a reticle and when a light, whose wavelength is different from an exposing wavelength, is used as alignment light. CONSTITUTION:An inherent focal length corresponds to the amount of the chromatic aberration of a projection optical system, which is yielded by the different between the light sensitive wavelength of a light sensitive substrate W, which is one object of alignment, and the wavelength of alignment light LB. A light spot having a specified shaped is formed in a space by the projection of the alignment light LB in a special pattern having a lens characteristic. The special pattern is formed at a reticle R, which is another object to be aligned. The light spot through the special pattern is projected on the pattern on the light sensitive substrate W through the projection optical system. Detected light LC, which is yielded in the pattern, is received. The position information of the pattern is obtained in an optoelectronic detecting means 34. In this way, the alignment accuracy is improved without any optical element for correction. |
