Photomask, an exposure method and a projection exposure apparatus

摘要

A photomask is provided having a stepped portion formed on at least one of a first and second areas corresponding to a stepped structure within an exposure area on the sensitive substrate onto which the pattern is to be exposed to make different height positions of the first and second areas of the pattern forming surface of the transparent substrate in the optical axis direction of the projection optical system. Also provides is an exposure method involving the step of shifting an image forming surface of a projection optical system in an optical axis direction corresponding to a stepped structure of an exposure area on a sensitive substrate. The image forming surface of the projection optical system coincides with the exposure area surface when exposing the pattern on an original substrate onto the sensitive substrate through the projection optical system. A projection exposure apparatus is also provided including a projection optical system for projecting and forming an image of a pattern on the original substrate on the sensitive substrate, and a stage for retaining the sensitive substrate so that the surface of the sensitive substrate is disposed close to the image forming surface. The exposure apparatus also has an image surface compensating member for shifting the image forming surface in the optical axis direction corresponding to the stepped structure.