Method and apparatus for forming metal contacts on a substrate

Abstract

Metal traces and 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 metal trace geometries.

1 . An intermediate solder ball forming apparatus comprising: 
 a mold substrate comprising; 
 an upper surface,  
 a lower surface, and  
 at least one cavity formed in the lower surface of the substrate having a layer having a first degree of wettability relative to solder paste;  
   a carrier substrate disposed below the mold substrate comprising: 
 a surface abutting the lower surface of the mold substrate, and  
 at least one bond pad disposed on the surface of the carrier substrate below the at least one cavity formed in the lower surface of the mold substrate, the at least one bond pad having a second degree of wettability relative to solder paste that is greater than the first degree of wettability of the layer of the at least one cavity; and  
 solder paste disposed within the at least one cavity adjacent the layer thereof, gravity acting on the solder paste moving it from the layer of the at least one cavity to the bond pad disposed on the carrier substrate.  
   
     
     
         2 . An intermediate solder ball forming apparatus comprising: 
 a mold substrate comprising; 
 an upper surface,  
 a lower surface, and  
 at least one cavity formed in the lower surface of the substrate having a layer having a first degree of wettability for solder paste;  
   a carrier substrate disposed below the mold substrate comprising: 
 a surface abutting the lower surface of the mold substrate, and  
 at least one bond pad disposed on the surface of the carrier substrate below the at least one cavity formed in the lower surface of the mold substrate, the at least one bond pad having a second degree of wettability relative for solder paste at least greater than the first degree of wettability of the layer of the at least one cavity; and  
   solder paste disposed within the at least one cavity adjacent the layer thereof for having gravity to act on the solder paste for moving the solder paste from the layer of the at least one cavity to the bond pad disposed on the carrier substrate.    
     
     
         3 . A solder ball forming apparatus comprising: 
 a mold substrate comprising; 
 an upper surface,  
 a lower surface, and  
 at least one cavity formed in the lower surface of the substrate having a layer having a first degree of wettability for solder paste;  
   a carrier substrate disposed below the mold substrate comprising: 
 a surface abutting the lower surface of the mold substrate, and  
 at least one bond pad disposed on the surface of the carrier substrate below the at least one cavity formed in the lower surface of the mold substrate, the at least one bond pad having a second degree of wettability for solder paste at least greater than the first degree of wettability of the layer of the at least one cavity; and  
 solder paste disposed within the at least one cavity adjacent the layer thereof for having gravity to act on the solder paste for moving the solder paste from the layer of the at least one cavity to the bond pad disposed on the carrier substrate.