Rigorous diffraction analysis for future mask technology
Advanced lithographic techniques such as phase shift masks (PSM) and optical proximity correction (OPC) result in a more complex mask design and technology. With shrinking feature sizes, the topography of the mask becomes more and more important. We compare diffraction spectra, aerial images and resist profiles, which result from rigorous simulations to such one which are obtained with the assumption of an infinitely thin mask (Kirchhoff approach). The rigorous simulations were performed with a time-domain finite-difference algorithm. Consequences with respect to process linearity, mask error factor, printability of small assist features in OPC and phase defects in PSM will be discussed.