CHIP-ON-CHIP STRUCTURE AND METHODS OF MANUFACTURE
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.
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.