Apparatus for imprint lithography using an electric field

Abstract

A lithography process for creating patterns in an activating light curable liquid using electric fields followed by curing of the activating light curable liquid is described. The process involves the use of a template that is formed of non-conductive and electrically conductive portions. The template is brought into close proximity to the activating light curable liquid on the substrate. An external electric field is applied to the template-substrate interface while maintaining a uniform, carefully controlled gap between the template and substrate. This causes the activating light curable liquid to be attracted to the raised portions of the template. Activating light is applied to the curable liquid while an electric field is applied to the template to create a patterned layer on the substrate.

1 . An apparatus for applying a pattern to a curable liquid disposed on a substrate, said apparatus comprising:
 a template having an electrically non-conductive base layer coupled to an electrically conductive layer with raised planarized areas corresponding to said pattern;   a positioning device for coupling to and holding said template parallel to said curable liquid, wherein said positioning device is suitable for positioning said template a controlled distance proximate to a surface of said substrate;   a voltage source having a first terminal electrically coupled to said electrically conductive layer of said template and a second terminal electrically coupled to said substrate; and   an energy source for transmitting energy to harden said curable liquid, wherein said pattern is formed in response to positioning said template toward the substrate, setting a potential of the voltage source and impinging said energy from said energy source to said curable liquid.   
     
     
         2 . The apparatus as recited in  claim 1 , wherein said template is substantially transparent to an activating light as said energy source. 
     
     
         3 . The apparatus as recited in  claim 2 , wherein said activating light comprises wavelengths selected from, ultraviolet, visible, and infrared bands. 
     
     
         4 . The apparatus as recited in  claim 1 , wherein said electrically conductive layer comprises Indium Tin Oxide (ITO). 
     
     
         5 . The apparatus as recited in  claim 4 , wherein said electrically insulative layer comprises fused silica. 
     
     
         6 . The apparatus as recited in  claim 1 , wherein controlled distance is in a range of 100 nm or less. 
     
     
         7 . The apparatus as recited in  claim 1 , wherein said voltage source is adjusted to establish an electric field between said electrically conductive layer and said substrate that attracts said curable liquid to said template with sufficient force to overcome a surface tension of said curable liquid such that pattern areas of said curable liquid directly opposing said raised planarized areas of said electrically conductive layer are extended to form said pattern. 
     
     
         8 . The apparatus as recited in  claim 7 , said pattern areas of said curable liquid extend a distance sufficient to contact the raised planarized areas of the electrically conductive layer. 
     
     
         9 . The apparatus as recited in  claim 7 , said curable liquid is disposed onto a transfer layer on said substrate. 
     
     
         10 . The apparatus as recited in  claim 9 , wherein is etched to enhance an aspect ratio of said pattern. 
     
     
         11 . The apparatus as recited in  claim 10 , wherein transfer layer functions as an etch barrier to protect said substrate. 
     
     
         12 - 28 . (canceled) 
     
     
         29 . The apparatus as recited in  claim 7 , wherein the template is first positioned in a first proximity of said curable liquid with said positioning device while said voltage source is set at a first voltage potential and said voltage source is adjusted to a second voltage potential while said positioning device increases a gap between said template and said curable liquid to a second proximity, thereby further enhancing an aspect ratio of said pattern without said template contacting said curable liquid. 
     
     
         30 . The apparatus as recited in  claim 29 , wherein said curable liquid has a low viscosity such that said pattern may be formed by said electric field in a time period less than one second. 
     
     
         31 . The apparatus as recited in  claim 10 , wherein a metal layer is deposited over said substrate with said pattern as a step in a metal lift-off process.