Method and apparatus for rapid imprint lithography

Abstract

In accordance with the invention, a mold for imprinting a patterned region by imprint lithography is provided with a peripheral groove around the patterned region. The groove is connected, as by channels through the mold, to a switchable source for gas removal to prevent bubbles and for the application of pressurized gas to separate the mold and substrate. In use, the mold is disposed adjacent the moldable surface and gas is withdrawn from the patterned region through the groove as the mold is pressed toward and into the moldable surface. At or near the end of the imprinting, the process is switched from removal of gas to the application of pressurized gas. The pressurized gas passes through the groove and separates or facilitates separation of the mold and the moldable surface.

1 . A method of imprint lithography comprising the steps of:
 providing a substrate having a moldable surface;   providing a mold having a molding surface for imprinting onto the moldable surface, the molding surface substantially surrounded by a surface groove for conducting fluid;   disposing the mold adjacent the substrate with the molding surface adjacent the moldable surface;   pressing the molding surface against the moldable surface to imprint the moldable surface;   hardening the moldable surface; and   applying pressurized fluid through the groove to facilitate separation of the mold from the imprinted moldable surface.   
     
     
         2 . The method of  claim 1  further comprising the step of withdrawing fluid through the surface groove prior to or during the pressing. 
     
     
         3 . The method of  claim 1  wherein the pressing comprises sealing the region between the molding surface and the moldable surface to produce a sealed mold/substrate assembly and subjecting the mold/substrate assembly to direct fluid pressure. 
     
     
         4 . The method of  claim 3  wherein the sealing comprises withdrawing fluid through the surface groove. 
     
     
         5 . The method of  claim 1  wherein the pressing comprises pressing by a mechanical press. 
     
     
         6 . The method of  claim 1  further comprising a step of moving apart said substrate and said mold. 
     
     
         7 . The method of  claim 1  wherein said mold comprises a plurality of voids to connect said surface groove at one end and the surface opposite to said molding surface or the sidewall surface at the other end. 
     
     
         8 . The method of  claim 7  wherein said voids provide fluid passage to said surface groove. 
     
     
         9 . The method of  claim 1  wherein said surface groove is made by either machining, or by a lithographical patterning and etching. 
     
     
         10 . The method of  claim 1  wherein said mold comprises a plurality of bodies bonded together. 
     
     
         11 . Apparatus for imprinting a molding surface on a substrate having a moldable surface comprising in operative relationship:
 a mold having a molding surface, the molding surface substantially surrounded by a surface groove for conducting fluid;   a positioner for placing the mold adjacent the substrate with the molding surface adjacent the moldable surface;   pressing apparatus for pressing the mold against the substrate; and   a source of pressurized fluid switchably connected to introduce pressurized fluid through the surface groove to facilitate separation of the mold from the imprinted substrate.   
     
     
         12 . The apparatus of  claim 11  further comprising a controller to control the sequence of imprinting the moldable surface and introducing pressurized fluid into the groove to facilitate separation of the mold from the imprinted moldable surface. 
     
     
         13 . The apparatus of  claim 11  further comprising a pump or a low pressure reservoir switchably connected to the surface groove to withdraw fluid through the groove. 
     
     
         14 . The apparatus of  claim 13  further comprises a controller to control the sequence of withdrawing gas through the groove, imprinting the moldable surface and introducing pressurized fluid to facilitate separation of the mold from the imprinted surface. 
     
     
         15 . The apparatus of  claim 11  wherein the mold further comprises a plurality of through-holes connected to the surface groove. 
     
     
         16 . The apparatus of  claim 11  wherein the mold comprises a pattern of projecting and recessed features for imprinting at least one feature having a minimum lateral dimension of less than 200 nanometers. 
     
     
         17 . The apparatus of  claim 11  wherein the pressing apparatus comprises a mechanical press. 
     
     
         18 . The apparatus of  claim 11  wherein the pressing apparatus comprises a pressure vessel for enclosing the mold and substrate and a source of pressurized fluid for introducing pressurized fluid into the chamber. 
     
     
         19 . The apparatus of  claim 18  further comprising a controller to control the sequence of introducing pressurized fluid into said vessel to imprint the moldable surface and introducing pressurized fluid into the groove to facilitate separation of the mold from the imprinted moldable surface. 
     
     
         20 . The apparatus of  claim 18  further comprising a pump or a low pressure fluid reservoir switchably connected to the surface groove to withdraw fluid through the groove. 
     
     
         21 . The apparatus of  claim 20  further comprising a controller to control the sequence of disposing the mold and substrate in the pressure chamber, withdrawing fluid through the groove to seal the region between the molding surface and the moldable surface, introducing pressurized fluid into the chamber to imprint the moldable surface, and introducing pressurized fluid into the surface groove to facilitate separation of the mold and the imprinted substrate. 
     
     
         22 . The apparatus of  claim 11  wherein said mold comprises a plurality of voids to connect said surface groove at one end with the surface opposite to said molding surface or the sidewall surface at the other end. 
     
     
         23 . The apparatus of  claim 22  wherein said voids provide fluid passage to said surface groove. 
     
     
         24 . The apparatus of  claim 11  wherein said surface groove is made by either machining or by lithographic patterning and etching. 
     
     
         25 . The apparatus of  claim 11  wherein said mold comprises a plurality of bodies bonded together.