Patent ID: 8027091

Claim:
Method for correcting optical proximity effects when imaging a pattern, arranged in an object surface of a projection objective, into an image surface of the projection objective, wherein a multiplicity of optical elements and at least one pupil surface that is Fourier-transformed to the image surface are arranged between the object surface and the image surface, comprising: optical filtering of imaging light with at least one optical proximity correction (OPC) filter inserted between the object surface and the image surface in accordance with an OPC-filter function that is adapted to the pattern and corresponds to a spatially dependent transmission filtering in a region of the pupil surface, and selecting the OPC-filter function for the projection objective in accordance with a position of diffraction orders caused by the pattern such that variations in line widths in the image surface that are generated by interference of the diffraction orders are weaker than corresponding variations for the projection objective without the optical filtering.