IMAGE FORMATION DEVICE

摘要

PURPOSE: To provide a focus detection device having accuracy and reliability higher than a conventional device and capable of detecting a local inclination on the surface of a substrate. CONSTITUTION: The image formation device is provided with an image formation system PL, the image face of an image formation system and a 2nd face for executing image formation. A focus error detection device is provided with a radiant ray source S for supplying a beam bf having a wide wavelength band, an objective grating G1 and an image grating G2 mutually forming images through the 2nd face. The focus detection device can use a reference beam br reflected by the outer face RP of the image formation system by combining the wide band beam and gratings or without combining them. Thus an inclination detection device for detecting the position of the 2nd face against the image face can be obtained by using these a plurality of focus detection devices.