Device manufacture involving lithographic processing

[52.

• Device fabricated in accordance with the method of claim 1.]53. Method of device fabrication comprising at least one lithographic delineation step comprising projection of patterned radiation on an imaging material by means of a lens system to produce a pattern image, in which a mask is illuminated by irradiation 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 some equivalent conjugate plane of such lens system, said filter including two types of filter regions, one of which, is relatively transparent to said patterned radiation, and defines 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. 54. Method of claim 53 in which the edge acuity of
• the said pattern is at least as good as 0.2 .mu.m. 55. Method of claim 53 in which the minimum feature size of the said pattern is of a maximum of
• 1.0 .mu.m. 56. Method of claim 53 in which the entirety of the said
• pattern is produced by simultaneous illumination of the said mask. 57. Method of claim 53 in which the said pattern is produced by step and
• repeat. 58. Method of claim 53 in which the back focal plane filter blocks
• transmission above some degree of scatter. 59. Method of claim 58 in which the relatively transparent region is a circular aperture on the optic axis
• of the lens system. 60. Method of claim 53 in which the back focal plane
• filter blocks transmission below some degree of scatter. 61. Method of claim 60 in which the back focal plane filter blocks transmission above
• some degree of scatter. 62. Method of claim 53 in which the said mask includes two types of mask regions which produce different degrees of scattering on illuminating radiation so that said patterned radiation is pattern-defined by such degrees of scattering.

System for device fabrication comprising at least one lithographic delineation step to produce a pattern image on a body comprising said device under fabrication, said delineation step using a lens system and comprising projection of patterned electron radiation wherein a difference in electron scattering in two regions of a mask is primarily responsible for producing said patterned electron radiation, said system comprising:

• a source of electron radiation that has been accelerated through a potential of at least 50 kV;
• a back focal plane filter positioned in a transmission path of said patterned radiation, said back focal plane filter positioned on the back focal plane or an equivalent conjugate plane of said lens system, said back focal plane filter including two types of filter regions, the first of which is more transparent to said radiation than the second, so that the first filter region defines the pass portion of said filter, said second filter region serving to block transmission of a part of said radiation dependent upon degree of said scattering as imposed by said mask and wherein said back focal plane filter is configured and positioned such that lithographically significant distortion or movement of said more transparent filter region associated with heating resulting from said blocking of said pattern radiation is avoided;
• a lens system configured to project said patterned radiation formed by illuminating said mask with radiation from said radiation source to said back focal plane filter such that said pattern image is demagnified relative to the corresponding patterned radiation at said mask and such that in the absence of said back focal plane filter said production of said pattern image on said body is lithographically inadequate;
• a holder for said body having a resist region positioned to receive said pattern radiation traversing said back focal plane filter wherein the flux of said pattern radiation traversing said back focal plane filter is sufficient for lithographic exposure of said resist to allow formation of said pattern image.