System and method for analog replication of microdevices having a desired surface contour

Abstract

A master wafer is replicated by creating a mold by plating a nickel electroform on a surface of a silicon wafer. Thereafter, a child wafer is prepared with a layer of photoresist or similar material that is compatible with plasma-etching techniques. Thereafter, the mold shape is transferred to the photoresist through compression molding, thereafter the child wafer is etched.

1 . A method of making a master mold for use in forming micro-optical elements comprising: 
 depositing a release-aid layer on a substrate, the substrate having micro-elements etched into a surface of the substrate, where the release-aid layer maintains a shape of the micro-optical elements, the micro-elements having curved surfaces;    electroforming metal on the release-aid layer; and    removing the metal from the release-aid layer, where the metal has an imprint of the micro-optical elements, the removed metal forming the master mold.    
     
     
         2 . The method of  claim 1 , wherein the micro-elements are etched using a gray scale technique.  
     
     
         3 . The method of  claim 1 , wherein the metal is nickel.  
     
     
         4 . The method of  claim 1 , further comprising: 
 depositing a backing material onto the metal prior to the removing the metal step, wherein the removing the metal step removes the metal and backing material.    
     
     
         5 . The method of  claim 1 , wherein the release-aid layer is one of gold and Teflon.  
     
     
         6 . The method of  claim 1 , further comprising: 
 depositing an additional layer between the release layer and the electroformed metal.    
     
     
         7 . The method of  claim 6 , wherein the additional layer is a metal layer.  
     
     
         8 . A method of making micro-elements comprising: 
 depositing photoresist on a substrate;    developing the photoresist using UV light;    pressing a master mold into the developed photoresist;    removing the master mold from the photoresist leaving an imprint of micro-elements in the photoresist; and    etching the photoresist and the substrate forming a copy of the micro-elements in the substrate, where the micro-elements have curved surfaces.    
     
     
         9 . The method of  claim 8  wherein, the master mold is formed by gray scale etching.  
     
     
         10 . The method of  claim 8 , wherein the micro-optical elements have sizes greater than 1 μm.  
     
     
         11 . The method of  claim 8 , wherein the photoresist is a negative photoresist.  
     
     
         12 . The method of  claim 8 , wherein the photoresist material is a polyimide-based material.  
     
     
         13 . The method of  claim 8 , wherein the photoresist material is one of novalak and a phenyl-formaldehyde resin.