3-dimensional imprint tool

Abstract

The invention is a method for the fabrication of an imprint tool master. The process begins with a metallic substrate. A layer of photoresist is placed onto the metallic substrate and a image pattern mask is then aligned to the mask. The mask pattern has opaque portions that block exposure light and “open” or transparent portions which transmit exposure light. The photoresist layer is then exposed to light transmitted through the “open” portions of the first image pattern mask and the mask is then removed. A second layer of photoresist then can be placed onto the first photoresist layer and a second image pattern mask may be placed on the second layer of photoresist. The second layer of photoresist is exposed to light, as before, and the second mask removed. The photoresist layers are developed simultaneously to produce a multi-level master mandrel upon which a conductive film is formed. A tool master can now be formed onto the conductive film. An imprint tool is then produced from the tool master. In one embodiment, nickel is electroplated onto the tool master to produce a three-dimensional imprint tool.

What is claimed is:  
     
         1 . A method for fabricating an imprint tool master, comprising: 
 providing a metallic substrate;    forming a first photoresist layer onto said substrate;    aligning an image pattern mask onto said photoresist layer, wherein said pattern mask has portions that block exposure light and portions which transmit exposure light;    exposing said photoresist layer with a first exposure of exposure light;    removing said first pattern mask;    developing said first photoresist layer to produce a master mandrel;    forming a conductive film onto said master mandrel; and    forming a tool master on said conductive film.    
     
     
         2 . The method of  claim 1 , further comprising forming an embossing tool from said tool master.  
     
     
         3 . The method of  claim 2 , wherein the step of forming an embossing tool comprises: 
 passivating said tool master;    electroplating a metal layer onto said tool master; and    separating said metal layer from said tool master to provide said embossing tool.    
     
     
         4 . The method of  claim 3 , wherein the step of electroplating a metal layer includes electroplating a metal selected from the group consisting of the Transition series of metal listed in New IUPAC Group Numbers 4-12 of the Period Table of elements, tin, and any alloy thereof.  
     
     
         5 . The method of  claim 3 , wherein the step of electroplating includes electroplating nickel.  
     
     
         6 . The method of  claim 1 , wherein the step of providing a metallic substrate comprises providing a stainless steel substrate.  
     
     
         7 . The method of  claim 6 , wherein the step of providing a stainless steel substrate comprises providing a stainless steel substrate that is about 0.090 inches thick.  
     
     
         8 . The method of  claim 1 , wherein the step of providing a metallic substrate comprises providing a titanium substrate.  
     
     
         9 . The method of  claim 8 , wherein the step of providing a titanium substrate comprises providing a titanium substrate that is about 0.090 inches thick.  
     
     
         10 . The method of  claim 1 , wherein the step of forming a first photoresist layer onto said substrate comprises forming a first dry film photoresist layer on said substrate.  
     
     
         11 . The method of  claim 1 , wherein the step of forming a first photoresist layer onto said substrate comprises forming a first wet photoresist layer onto said substrate.  
     
     
         12 . The method of  claim 1 , wherein the step of aligning an image pattern mask comprises aligning a positive trace image pattern mask.  
     
     
         13 . The method of  claim 1 , wherein the step of aligning an image pattern mask comprises aligning a negative trace image pattern mask.  
     
     
         14 . The method of  claim 1 , wherein the step of forming a second photoresist layer comprises forming a second dry film photoresist layer.  
     
     
         15 . The method of  claim 1 , wherein the step of forming a second photoresist layer comprises forming a second wet photoresist layer.  
     
     
         16 . A method for fabricating an imprint tool master, comprising: 
 providing a metallic substrate;    forming a first photoresist layer onto said substrate;    aligning an image pattern mask onto said photoresist layer, wherein said pattern mask has first portions that block exposure light and first portions which transmit exposure light;    exposing said photoresist layer with a first exposure of exposure light;    removing said first pattern mask;    forming a second photoresist layer onto said first photoresist layer;    aligning a second pattern mask of a second desired pattern onto said second photoresist layer, wherein said second pattern mask has second portions that block exposure light and second portions which transmit exposure light;    exposing said second photoresist layer with a second exposure of said exposure light transmitted through said second portions;    removing said second pattern mask;    developing both said first photoresist layer and said second photoresist layer to produce a master mandrel;    forming a conductive film onto said master mandrel; and    forming a tool master on said conductive film.    
     
     
         17 . The method of  claim 16 , further comprising forming an embossing tool from said tool master.  
     
     
         18 . The method of  claim 17 , wherein the step of forming a tool comprises: 
 passivating said tool master;    electroplating a metal layer onto said tool master; and    separating said metal from said tool master.    
     
     
         19 . The method of  claim 18 , wherein the step of electroplating a metal layer includes electroplating The method of  claim 3 , wherein the step of electroplating a metal layer includes electroplating a metal selected from the group consisting of the Transition series of metal listed in New IUPAC Group Numbers 4-12 of the Period Table of elements, tin, and any alloy thereof.  
     
     
         20 . The method of  claim 18 , wherein the step of electroplating a metal layer includes electroplating nickel.  
     
     
         21 . The method of  claim 16 , wherein the step of providing a metallic substrate comprises providing a stainless steel substrate.  
     
     
         22 . The method of  claim 21 , wherein the step of providing a stainless steel substrate comprises providing a stainless steel substrate that is about 0.090 inches thick.  
     
     
         23 . The method of  claim 16 , wherein the step of providing a metallic substrate comprises providing a titanium substrate.  
     
     
         24 . The method of  claim 23 , wherein the step of providing a titanium substrate comprises providing a titanium substrate that is about 0.090 inches thick.  
     
     
         25 . The method of  claim 16 , wherein the step of forming a first photoresist layer onto said substrate comprises forming a first dry film photoresist layer on said substrate.  
     
     
         26 . The method of  claim 16 , wherein the step of forming a first photoresist layer onto said substrate comprises forming a first wet photoresist layer onto said substrate.  
     
     
         27 . The method of  claim 16 , wherein the step of aligning an image pattern mask comprises aligning a positive trace image pattern mask.  
     
     
         28 . The method of  claim 16 , wherein the step of aligning an image pattern mask comprises aligning a negative trace image pattern mask.  
     
     
         29 . The method of  claim 16 , wherein the step of forming a second photoresist layer comprises forming a second dry film photoresist layer.  
     
     
         30 . The method of  claim 16 , wherein the step of forming a second photoresist layer comprises forming a second wet photoresist layer.  
     
     
         31 . The method of  claim 16 , wherein the step of aligning a second pattern mask comprises aligning a second positive trace image pattern mask.  
     
     
         32 . The method of  claim 16 , wherein the step of aligning a second pattern mask comprises aligning a second negative trace image pattern mask.  
     
     
         33 . The method of  claim 16 , wherein the step of forming a conductive film comprises forming a conductive film by particle vapor deposition.  
     
     
         34 . The method of  claim 16 , wherein the step of forming a conductive film comprises forming a copper film.  
     
     
         35 . A 3 dimensional embossing tool, comprising: 
 an electroformed metal sheet having a print positive electroformed image of an embossing pattern, said pattern including a plurality of structures having variable geometries and minimum feature dimensions as small as about 0.0005 inches.    
     
     
         36 . The embossing tool of  claim 35 , wherein said plurality of structures include multi-layered structures.  
     
     
         37 . The embossing tool of  claim 36 , wherein each of said layers has a thickness ranging from about 0.0005 inch to about 0.01 inch.  
     
     
         38 . A tool master for forming a 3 dimensional embossing tool, comprising: 
 an electroformed metal sheet having a print negative image of an embossing structure formed into said electroformed sheet, said sheet formed by electroplating a thickness of a metal over a print positive image comprising a metallic coated photoresist.