Patent ID: 7588882

Claim:
Lithographic method for fabricating three-dimensional structures on the micrometric and submicrometric scale, including the operations of: providing a substrate; depositing on the said substrate a first layer of a first polymeric material sensitive to exposure to charged particles or to electromagnetic radiation; depositing, on the first layer of the first material, a layer of a second polymeric material sensitive to exposure to charged particles or to electromagnetic radiation in a different way from the first material, so that the processes of exposure and development of the two materials are mutually incompatible to the extent that the exposure or development of one of the materials does not interfere with the exposure and development of the other material; forming a pattern on the second material by a litho-graphic process, comprising the steps of: exposing the layer of the second material to charged particles or electromagnetic radiation according to a predetermined topography so as to define a first and a second portion of the layer of the second material, respectively exposed and unexposed to the said particles or to the said radiation; and subsequently selectively removing one of said first and second portions of the layer of the second material, so that regions of the first layer of the first material are left uncovered; depositing, on the patterned layer of the second material and on the uncovered regions of the first layer of the first material, a second layer of the first material; and forming a pattern on the first and second layers of the first material by a litho-graphic process, comprising the steps of: exposing the first and second layers of the first material to charged particles or electromagnetic radiation according to a predetermined topography so as to define a first and a second portion of the first and second layers of the first material, respectively exposed and unexposed to the said particles or to the said radiation; subsequently, selectively removing one of said first and second portions of the first and second layers of the first material, wherein the second material is transparent to the particles or to the electromagnetic radiation to which the first material is sensitive.