Fundamental understanding and experimental verification of bright versus dark field imaging

In this work we consider the fundamentals of bright and dark field imaging based on the diffraction theory of aerial image formation and its application to EUV lithography. We show that bright field imaging has an intrinsic potential for higher optical (N)ILS, especially for isolated features, but with a lower depth of focus. Also, experimental bright vs dark field results obtained on an NXE:3400 scanner and on AIMSTM EUV at Zeiss will be shown. The main goal of the paper is to draw attention to bright versus dark field comparison for EUV and to kick off more studies in this direction.