Imprint lithography system and method for manufacturing

Abstract

A nanoimprint lithography system and method for manufacturing substrates with nano-scale patterns, having a process chamber with transparent sections on both top and side walls, a robot for automatic molds and substrates loading and unloading, and optical and stage apparatuses to obtain the desired spatial relationship between the mold and substrate, with an enclosed volume referring to mold mini-chamber being formed between the mold/holder and top wall of the chamber and with the process chamber and mini-chamber being capable of both vacuuming and pressurizing, and inside the chamber, a ring shape seal assembly is installed and a mold support assembly can be installed that aids in imprinting all the way to the edge of the substrate with various embodiments for carrying out fluid pressure imprinting, separation, measurement and control of mold and substrate gap, substrate thickness, and system axial force.

What is claimed is: 
     
         1 . A method to pattern nanostructures on a substrate from a mold comprising the steps of:
 having a mold having a mold surface with nanostructures;   having a substrate having a surface;   depositing a deformable material on the surface of the substrate;   
       positioning in a chamber the substrate with the deposited deformable material in a position facing the mold surface of the mold having the nanostructures and having a gap there between;
 applying a vacuum in the chamber including the gap defined between the positioned substrate and mold; 
 
       sealing the moldable surface of the substrate and the molding surface of the mold; 
       pressing the mold and substrate for a predetermined period of time; and
 separating the substrate and the mold with the deformable material remaining on the substrate and being patterned with nanostructures corresponding to the nanostructures of the mold surface. 
 
     
     
         2 . The method of  claim 1  wherein sealing includes
 determining an initial distance of the gap between the mold surface and the moldable substrate surface; 
 adjusting at least one of the substrate and the mold to establish the predetermined value of the distance of the gap; and 
 
       sealing the mold and substrate surfaces. 
     
     
         3 . The method of  claim 1  wherein pressing includes:
 applying at an initial predetermined/controlled pressure one or more gases in an area of the chamber that is proximate to the mold and the substrate; 
 retracting a movable ring (if it is existing) from the sealing surface; 
 applying at predetermined/controlled pressures one or more gases in an area of the chamber that is proximate to the mold and the substrate; and 
 
       removing the applied gases to return the pressure to atmospheric pressure. 
     
     
         4 . The method of  claim 3  wherein the pressing includes fluid pressure applied at a pressure of between about −14.6 psi and about 1000 psi. 
     
     
         5 . The method of  claim 4  wherein the fluid pressure is supplied by a non-reactive gas from a group of gases selected from the group consisting of nitrogen, air, argon, and helium. 
     
     
         6 . The method of  claim 2  wherein the sealing is accomplished by pressing a movable ring to contact the edge of the substrate or the mold, wherein the ring has flexible materials mounted on the side to be contacted with the mold and substrate. 
     
     
         7 . The method of  claim 2  wherein the sealing is accomplished by deforming a portion of the mold to contact with the substrate, or deforming a portion of the substrate to be contact with the mold. 
     
     
         8 . The method of  claim 7  wherein by setting a predetermined gap between mold and substrate before deforming, the area of deformed portion is larger than area that requires patterning. 
     
     
         9 . The method of  claim 7  wherein deforming a portion of the mold or substrate includes
 securing at least one of the substrate and the mold; 
 determining an initial distance of the gap between the mold surface and the substrate surface; 
 adjusting at least one of the substrate and the mold to establish the predetermined value of the distance of the gap; 
 after the predetermined gap distance is adjusted, applying a predetermined differential pressure to the main chamber and mini-chamber to move the mold and/or substrate into contact; 
 increasing the pressure of both main chamber and mini-chamber to a final imprint pressure while maintaining at least the initial pressure difference; and 
 
       increasing the substrate chuck pressure to the final imprint pressure. 
     
     
         10 . The method of  claim 3  wherein applying the controllable force includes applying upward uniform fluid pressure on the substrate so the opposing sides of the substrate and the mold freely contact each other. 
     
     
         11 . The method of  claim 1  wherein separating includes
 retaining at least a portion of a non-contact side of the mold that is opposing the mold surface; 
 retaining at least a portion of a non-contact side of the substrate that is opposing the surface having the deformable material deposited thereon; 
 moving the substrate away from the mold in a series of controlled motions until the substrate is released from the mold, said controlled motion being controlled for movement in one or more of 6 axis x, y, z, theta, tip, tilt and including one or more control factors selected from the group consisting of distance, motion, force speed, acceleration, deceleration, and time. 
 
     
     
         12 . The method of  claim 1  wherein separating includes
 retaining at least a portion of a non-contact side of the mold that is opposing the mold surface; 
 retaining at least a portion of a non-contact side of the substrate that is opposing the surface having the deformable material deposited thereon; 
 deforming the mold until initially a peripheral region of the substrate is first released from the mold, said deforming being effected by a differential pressure between two opposing sides of the mold; and 
 restoring the mold to its original shape until the substrate is released from the mold. 
 
     
     
         13 . The method of  claim 1  wherein the applying of vacuum includes removing the gas molecules from the spacing between the mold and the substrate to a pressure of between about 0.1 to about 25 torr. 
     
     
         14 . A system for patterning a substrate comprising:
 a mold holding fixture for holding a mold having a mold surface with nanostructures;   a substrate holding fixture for holding a substrate having a molding surface;   a stage assembly having at least one axis movement;   a contact force sensor positioned for sensing a contact force between the mold surface and the molding surface;   a chamber housing defining a chamber having at least a mold held by the mold holding fixture and the substrate held by the substrate holding fixture positionable therein, the chamber housing configured enabling the applying of a pressure inside the chamber that is higher and/or lower than atmospheric pressure;   a mold supporting assembly which provides support to reduce the mold deforming at certain area of the mold, or a movable ring to support and seal the edge of substrate and mold with controlled pressure;   a pressure regulator and a manifold each being fluidly coupled to the chamber for changing the pressure inside the chamber;   a gas reservoir of high pressure, a regulator and piping to allow the high pressure gas;   at least one vacuum pump;   a dispenser assembly to place moldable materials on the substrate;   a door on the chamber housing, or a movable bottom chamber, or a movable top chamber for selectively allowing the substrate and the mold to pass there through; and   means to divide the chamber into two fluidly separate sub-chambers, each sub-chamber being configured for a separate controlled sub-chamber environment including a separate pressure and/or vacuum, a separate gas content, and a separate gas flow rate into and out thereof.   
     
     
         15 . The system of  claim 14  wherein the mold holding fixture is configured for holding only a periphery of the mold, said mold holding fixture being hollow to expose a central area of the mold for accessing from the side of the molding surface and the opposing side, the mold holding fixture being attached to inner surface of the chamber and having substantially flat surfaces for uniformly holding the mold with substantially distributed equalized pressure for minimizing deformation of the held mold. 
     
     
         16 . The system of  claim 14  wherein the movable ring is driven by an air cylinder with pressure adjustable from 0-90 psi, a piezo stage with controlled force, or a solenoid with controlled force. 
     
     
         17 . The system of  claim 14  wherein the movable ring has a flexible sealing material on its seal surface, the flexible sealing material is made of a flexible plastic material selected from the group consisting of Telfon, Viton, Silicon and Kelrez. 
     
     
         18 . The system of  claim 14  wherein the mold supporting assembly has a hollow center opening that can be configured for mounting on the mold holder, leaving the patterning area of mold surface open or can be configured for mounting on the substrate holder, leaving the moldable surface of the substrate open, wherein the height of the assembly can be configured for further adjustment by inserting spacers or setting adjustable screws. 
     
     
         19 . The system of  claim 18  wherein the hollow center of the mold supporting assembly has an opening diameter 0.01 mm-2 mm larger than the diameter of the substrate. 
     
     
         20 . The system of  claim 14 , further comprising a robot having end effectors and controlled by a computer with computer executable instructions, each configured for placement of a substrate in a first position inside the chamber, and placement of a mold in a second position inside the chamber cavity. 
     
     
         21 . The system of  claim 14  wherein the chamber housing includes one or more windows to the chamber configured for allowing light of one or more wavelengths to pass through the window while maintaining the applied pressure inside the chamber. 
     
     
         22 . The system of  claim 21  wherein at least one of the chamber windows is coated with multiple layer thin films for reducing light reflections on the window surfaces. 
     
     
         23 . The system of  claim 14 , further comprising
 at least one gap measurement device for determining a gap distance between the mold surface of the mold and the molding surface of the substrate while each is in the chamber; and   a gap distance control means for adjusting a position of at least one of the mold and the substrate to obtain a predetermined distance.   
     
     
         24 . The system of  claim 23  wherein the at least one gap measurement device includes at least one of an optical detection system configured for determining a spatial relationship between the mold and the substrate; or
 at least one sensor selected from the group consisting of a laser sensors, and optical sensors, an optical microscopes, and a radiofrequency transceiver sensor. 
 
     
     
         25 . The system of  claim 23  wherein the gap measurement device further includes one or more optical microscopes and wherein each of the mold and the substrate include alignment marks, the optical microscopes configured and positioned for observing each of the mold and the substrate alignment marks when the mold and the substrate are positioned within the chamber under an applied pressure. 
     
     
         26 . The system of  claim 14 , further comprising at least one of
 means to deform the mold transversely toward or away from the substrate while each are within the chamber; and   means to deform the substrate towards or away from the mold using multiple motions capable of six degree of freedom while each are within the chamber.   
     
     
         27 . The system of  claim 14 , further comprising one or more UV lamps positioned either outside or inside of the chamber for exposing UV radiation onto the substrate. 
     
     
         28 . The system of  claim 14  wherein the mold is made of at least one material selected from the group consisting of a quartz, a glass, a silicon, a Ni, a plastic, a metal, and a semiconductor, and wherein the mold has a mold thickness of between about 0.001 mm to about 25 mm. 
     
     
         29 . A method to pattern nanostructures on a substrate all the way to the edge by:
 having a substrate having a surface;   depositing a deformable material on the surface of the substrate;   having a mold with a molding surface;   mounting a mold support assembly;   positioning in a chamber the substrate with the deposited deformable material in a position facing the mold surface of the mold having the nanostructures and having a gap there between;   applying a vacuum in the chamber including the gap defined between the positioned substrate and mold;   sealing the moldable surface of the substrate and the molding surface of the mold;   pressing the mold and substrate for a predetermined period of time; and   separating the substrate and the mold with the deformable material remaining on the substrate and being patterned with nanostructures corresponding to the nanostructures of the mold surface.