Particle-optical imaging system for lithographical purposes has lens arrangement with ring pre-electrode facing mask holder to form grid lens having negative refractive index with mask foil

摘要

Imaging system has illumination system (QL), mask holder (MH) and projection system arranged along an optical axis. One optical system has a ring electrode and different electrostatic potentials are applied to the ring electrode and mask foil (MF) acting as grid electrode, together forming grid lens with negative refractive index. First lens arrangement (BS) has a ring pre-electrode (VE) on the side facing the mask holder at a different electrical potential from the mask foil to form a grid lens with negative refractive index with the mask foil.