system with high accuracy with reference to proximity position transverse and parallel to the optical axis rotary position and tilted position the wafer is subsequently exposed with the light coming from the laser 2 which is directed into the second partial path 19 b with the aid of the optical deflector a structure produced by the second mask 9 is transferred onto the wafer during the exposure in the second exposure the mask 9 is a transmission phase mask that is suitable for imaging fine structures for example the gate structures of transistors the light striking the phase mask 9 is intended to strike the mask 9 in as parallel a way as possible for which reason the illumination system is optimized for a coherent conventional illumination with low degrees of coherence u03c3 lt 0 35 and the projection objective 10 has a high numerical aperture the projection system 18 is therefore specialized for exposure with a phase mask 9 it is therefore impossible to set off axis illumination for example on said system the illumination system therefore has neither adjustable axicon elements nor a changing device for optical components after the second exposure the wafer is transferred from the second exposure position 13 into an output position 16 the double exposure of the wafer thereby being terminated the structures produced on the photosensitive layer of the substrate are subsequently processed in a process step not illustrated pictorially for the purpose of patterning the substrate if appropriate the wafer is provided thereafter with a new photosensitive layer such that a further exposure process for example another process of double exposure can be undertaken until all structures required for producing a semiconductor component are produced on the wafer as an alternative to the case illustrated here by.