Photolithographic systems and methods for producing sub-diffraction-limited features

Abstract

Systems and methods for near-field photolithography utilize surface plasmon resonances to enable imaging of pattern features that exceed the diffraction limit. An example near-field photolithography system includes a plasmon superlens template including a plurality of opaque features to be imaged onto photosensitive material and a metal plasmon superlens. The opaque features and the metal superlens are separated by a polymer spacer layer. Light propagates through the superlens template to form an image of the opaque features on the other side of the superlens. An intermediary layer including solid or liquid material is interposed between the superlens and a photoresist-coated semiconductor wafer to reduce damage resulting from contact between the superlens template and the photoresist-coated semiconductor wafer.

1 . A method of fabricating an integrated circuit device on a semiconductor wafer, said method comprising:
 depositing a material to be patterned over said semiconductor wafer;   depositing a photosensitive layer on said material to be patterned, said photosensitive layer having a first index of refraction and responsive to light having a wavelength, λ;   disposing a superlens template in an optical path between a light source operable to provide said light and said photosensitive layer, said superlens template comprising a plurality of features substantially opaque to said light, a dielectric material disposed forward of said plurality of opaque features, said dielectric material being substantially transmissive to said light, and a superlens disposed forward of said dielectric material;   interposing an intermediary layer between said superlens and said photosensitive layer to reduce contact of said superlens with said photosensitive layer, the intermediary layer comprising material substantially transmissive to said light, the intermediary layer not permanently in contact with said superlens; and   directing said light into said superlens template thereby exposing portions of said photosensitive layer to said light.   
     
     
         2 . The method of  claim 1 , said method further comprising:
 developing said photosensitive layer;   etching said material; and   removing said photosensitive layer.   
     
     
         3 . The method of  claim 1 , wherein directing said light into said superlens template thereby exposing portions of said photosensitive layer to said light produces a near-field image of said features in or on said photosensitive layer. 
     
     
         4 . The method of  claim 1 , wherein said photosensitive layer comprises photoresist. 
     
     
         5 . The method of  claim 1 , wherein said intermediary layer has a second index of refraction that is substantially equal to said first index of refraction of said photosensitive material. 
     
     
         6 . The method of  claim 1 , wherein said superlens comprises a layer of metal. 
     
     
         7 . The method of  claim 6 , wherein said metal comprises silver, gold, or titanium. 
     
     
         8 . The method of  claim 1 , wherein said dielectric material comprises polymethyl methacrylate. 
     
     
         9 . The method of  claim 1 , wherein said intermediary layer comprises an organic material. 
     
     
         10 . The method of  claim 1 , wherein said intermediary layer comprises a solid. 
     
     
         11 . The method of  claim 1 , wherein said intermediary layer comprises a liquid. 
     
     
         12 . The method of  claim 11 , further comprising providing said liquid from a fluid output port and removing said liquid from a liquid input port. 
     
     
         13 . The method of  claim 11 , wherein interposing said intermediary layer comprises flowing said liquid between said superlens and said photosensitive layer. 
     
     
         14 . The method of  claim 13 , further comprising controlling a rate of flow of said liquid between said superlens template and said photosensitive layer. 
     
     
         15 . The method of  claim 11 , wherein interposing said intermediary layer comprises submerging at least a portion of said photosensitive layer in said liquid. 
     
     
         16 . The method of  claim 1 , further comprising providing said intermediary layer as a coating on said photosensitive layer. 
     
     
         17 . The method of  claim 16 , wherein providing said intermediary layer as a coating comprises depositing said coating on said photosensitive layer. 
     
     
         18 . The method of  claim 16 , wherein said coating comprises a plurality of layers. 
     
     
         19 . The method of  claim 18 , wherein at least one of said plurality of layers is configured to provide release of said coating from said photosensitive layer. 
     
     
         20 . The method of  claim 16 , further comprising removing said coating from said photosensitive layer after directing said light into said superlens template. 
     
     
         21 . The method of  claim 20 , wherein removing said coating comprises stripping said coating with a chemical solvent or a rinse agent. 
     
     
         22 . The method of  claim 1 , wherein interposing said intermediary layer between said superlens and said photosensitive layer further comprises providing a substantially constant vertical separation between said superlens and said photosensitive layer. 
     
     
         23 . The method of  claim 1 , further comprising relatively positioning said photosensitive layer and said superlens template 
     
     
         24 . The method of  claim 23 , wherein relatively positioning said photosensitive layer and said superlens template comprises maintaining said photosensitive layer in the near-field of said superlens while directing said light into said superlens template.