Chip-on-chip structure and methods of manufacture

Abstract

Sintered connection structures and methods of manufacture are disclosed. The method includes placing a powder on a substrate and sintering the powder to form a plurality of pillars. The method further includes repeating the placing and sintering steps until the plurality of pillars reach a predetermined height. The method further includes forming a solder cap on the plurality of pillars. The method further includes joining the substrate to a board using the solder cap.

What is claimed: 
     
         1 . A structure, comprising:
 a plurality of sintered pillars with a solder cap,   a chip joined to the wafer, between a plurality of sintered copper pillars;   a laminate board joined to the wafer by the solder cap of the plurality of sintered copper pillars or other conductive material; and   an underfill material bonding the chip, the wafer and the laminate board.   
     
     
         2 . The structure of  claim 1 , wherein the plurality of sintered pillars are one of tapered and hourglass shaped. 
     
     
         3 . The structure of  claim 1 , wherein the plurality of sintered pillars have a height of approximately 75 μm or greater on a wafer. 
     
     
         4 . The structure of  claim 1 , wherein the plurality of sintered pillars are copper sintered pillars. 
     
     
         5 . The structure of  claim 1 , wherein the plurality of sintered pillars have a height of approximately 500 μm. 
     
     
         6 . The structure of  claim 1 , wherein the plurality of sintered pillars are tapered. 
     
     
         7 . The structure of  claim 1 , wherein the plurality of sintered pillars are shaped as an hourglass. 
     
     
         8 . The structure of  claim 1 , wherein the plurality of sintered pillars are shaped are shaped as cones with its bases being wider in diameter than its end at the solder cap.