| 摘要 |
<P>PROBLEM TO BE SOLVED: To efficiently and precisely measure wavefront information of an optical system to be inspected, based on interference fringes obtained by a diffraction grating. <P>SOLUTION: By the method of measuring wavefront, luminous flux through a reticle 4 for measurement and a projection optical system PO is allowed to impinge on a two-dimensional diffraction grating 10, and wavefront information of the projection optical system PO is obtained based on interference fringes 22 by luminous flux generated from the diffraction grating 10. In the method of measuring wavefront, intensity distribution of the interference fringes 22 is measured each time when the diffraction grating 10 is moved by a prescribed amount in X and Y directions, and shearing wavefront in the X direction and shearing wavefront in the Y direction of luminous flux through the projection optical system PO are found from a plurality of measurement results of the intensity distribution. <P>COPYRIGHT: (C)2011,JPO&INPIT |
