Abstract:
A method is described for imaging, by means of projection radiation, a phaseshifting mask pattern on a substrate for the purpose of configuring device features in the substrate. By using a mask pattern comprising mask features constituted by a phase transition (22) and two sub-resolution assist features (40,41), arranged symmetrically with respect to the phase transition and having a mutual distance (p), device features having a wide variety of widths can be obtained by varying only the mutual distance.