Device manufacture involving lithographic processing

Method for device fabrication comprising at least one fabrication step including a lithographic delineation step, said delineation step using a lens system including a field-defined lens and comprising projection of patterned radiation to produce a pattern image on a body comprising a device under fabrication in order to selectively process such pattern image during the said fabrication step, in which a mask is illuminated by radiation from a charged particle radiation source to result in transmission of said patterned radiation, characterized in that the transmission path of said patterned radiation includes a "back focal plane filter" defined as positioned on the back focal plane or on some equivalent conjugate plane of such lens system, said filter including two types of filter regions, the first of which, is more transparent to said patterned radiation than the second, so that the first filter region/regions define the pass portion of said filter, said filter serving to block transmission of a part of said patterned radiation dependent upon degree of scatter as imposed by said mask, said method being further characterized in that such lithographic delineation step, itself, consists of a plurality of delineation procedures so that the pattern image on the body consists of a plurality of sub-images which are stitched together and in that image quality is enhanced by adjustment of said apparatus intermediate some such delineation procedures, such adjustment here denoted "dynamic correction".