Method for forming metal contacts on a substrate

Abstract

Solder bump pads are formed on a semiconductor substrate by way of a semiconductor template that has been micromachined to receive solder paste material. The solder paste material is then formed into precisely controlled ball shapes and geometries.

1 . A method of forming at least one of solder bump and a trace comprising: 
 providing a protective layer to a portion of the surface of a substrate;    removing a portion of the protective layer for forming at least one opening in the protective layer;    forming at least one cavity in the substrate using the at least one opening in the protective layer for holding material for forming at least one of a solder bump and a trace;    providing a nonstick protective layer in the at least one cavity; and    providing a heating area on another surface of the substrate.    
     
     
         2 . The method according to  claim 1 , wherein the protective layer comprises one of a silicon oxide layer and a silicon nitride layer.  
     
     
         3 . The method according to  claim 1 , wherein the protective layer prevents metal material from adhering to the at least one cavity.  
     
     
         4 . The method according to  claim 1 , further comprising: 
 applying a metal paste for forming the bump on the substrate;    spreading the metal paste across the surface within the at least one cavity;    heating the substrate to a temperature sufficient enough to partially melt the metal paste; and    removing the metal paste from within the at least one cavity upon contacting a portion of a substrate.    
     
     
         5 . The method according to  claim 4 , further comprising: 
 applying the mold to a secondary substrate;    using the partially melted metal paste to form a contact with the secondary substrate; and    removing the secondary substrate from the mold, the melted metal paste adhering solely to the secondary substrate.    
     
     
         6 . The method according to  claim 1 , wherein the at least one cavity includes one of a trapezoidally shaped cavity, a hemispherically shaped cavity, a rectangularly shaped cavity, and a square-shaped cavity.  
     
     
         7 . The method according to  claim 1 , further comprising providing at least one heating strip on a portion of the substrate.  
     
     
         8 . The method according to  claim 1 , further comprising: 
 providing a plurality of heating strips on the another surface of the substrate.    
     
     
         9 . The method according to  claim 7 , further comprising: 
 providing an electrical conductor having a portion connected to the at least one heating strip.    
     
     
         10 . The method according to  claim 8 , further comprising: 
 providing an electrical conductor having a portion thereof connected to the plurality of heating strips.    
     
     
         11 . A method for forming metal shapes including at least one bump and at least on trace, comprising: 
 applying a protective layer to a surface of a mold for forming at least one bump and at least one trace on a substrate;    masking the protective layer;    removing at least a portion of the protective layer to form at least one opening in the protective layer;    forming at least one cavity in the mold through the at least one opening in the protective layer;    forming a nonstick protective layer in the at least one cavity;    applying a material to the mold;    spreading the material across the surface of the mold within the at least one cavity;    heating the mold to a temperature sufficient enough to remove the material from the at least one cavity; and    removing the material from the at least one cavity.    
     
     
         12 . The method according to  claim 11 , further comprising: 
 applying the mold to the substrate; and    removing the substrate from the mold, the material adhering substantially to the substrate.    
     
     
         13 . The method according to  claim 11 , wherein the at least one cavity includes one of a trapezoidally shaped cavity, a hemispherically shaped cavity, a rectangularly shaped cavity, and a square-shaped cavity.  
     
     
         14 . The method according to  claim 11 , wherein heating the mold includes using at least one heating strip comprising a resistance heating strip.  
     
     
         15 . The method according to  claim 11 , further comprising: 
 forming a plurality of heating strips on the another surface of the mold.    
     
     
         16 . The method according to  claim 11 , further comprising: 
 forming an electrical conductor having a portion connected to the mold.    
     
     
         17 . The method according to  claim 15 , further comprising: 
 forming an electrical conductor having a portion thereof connected to the plurality of heating strips.    
     
     
         18 . A method of forming at least one bump and at least one trace on substrate using a mold, comprising: 
 applying a protective layer to a surface of said mold for forming bumps on a substrate;    masking the protective layer;    removing a portion of the protective layer to form at least one opening in the protective layer;    forming at least one cavity in the mold through the at least one opening in the protective layer, the at least one cavity for holding material to form a bump on the substrate, the cavity having at least one wall thereof sloped at essentially 54° relative to the plane of the substrate mold;    forming a nonstick protective layer in the at least one cavity; and    forming at least one heating strip on another surface of the mold.    
     
     
         19 . A method for forming a bump and a trace using a mold, comprising: 
 applying a protective layer to a surface of said mold for forming bumps on a substrate;    masking the protective layer;    removing at least a portion of the protective layer to form at least one opening in the protective layer;    forming at least one cavity in the mold through the at least one opening in the protective layer, the cavity having at least one wall thereof sloped at essentially 54° relative to the plane of the substrate mold;    forming a nonstick protective layer in the at least one cavity;    applying a material to the mold;    spreading the material across the surface of the mold within the at least one cavity;    heating the mold to a temperature sufficient enough for removing the material from the at least one cavity; and    removing the material from the at least one cavity.