Device manufacture involving lithographic processing
AssigneeAT&T Bell Laboratories
InventorsSteven D. Berger, John M. Gibson
Life of this patent
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Abstract
Fabrication of devices of micron and submicron minimum feature size is accomplished by lithographic processing involving a back focal plane filter. A particularly important fabrication approach depends upon mask patterns which produce images based on discrimination as between scattered and unscattered radiation by accelerated electrons.
Claims63
Method for device fabrication comprising at least one fabrication step including a lithographic delineation step, said delineation step using a lens system 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 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.
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.
Dependencies are inferred from the claim text.