Projection exposure apparatus and device manufacturing method including a projection optical system having a pair of diffractive members

A projection exposure apparatus comprising:

• a projection optical system for projecting a pattern of a mask onto a substrate, said projection optical system including a pair of diffractive members, at least one of which is displaced in a direction perpendicular to an optical axis of said projection optical system,
• wherein each of said pair of diffractive members has a diffraction grating surface whose shape is determined so that a refractive power of said pair of diffractive members varies when a positional relationship between the diffraction grating surfaces of said pair of diffraction members in the perpendicular direction varies, and
• wherein a refractive power of said projection optical system is adjusted by displacing said at least one of said pair of diffractive members in the direction perpendicular to the optical axis.

A projection exposure apparatus comprising:

• a projection optical system for projecting a pattern of a mask onto a substrate, said projection optical system including a pair of diffractive members, at least one of which is displaced in a direction perpendicular to an optical axis of said projection optical system,
• wherein each of said pair of diffractive members has a diffraction grating surface whose shape is determined so that an aberration of said pair of diffractive members varies in amount when a positional relationship between the diffraction grating surfaces of said pair of diffractive members in the perpendicular direction varies, and
• wherein an aberration of said projection optical system is adjusted by displacing said at least one of said pair of diffractive members in the direction perpendicular to the optical axis.