Semiconductor device having non-circular connectors

Abstract

A semiconductor device has semiconductor chip assembled on a substrate. The substrate has a first surface including conductive traces, which have a first length and a first width, the first width being uniform along the first length, and further a pitch to respective adjacent traces. The semiconductor chip has a second surface including contact pads; the second surface faces the first surface spaced apart by a gap. A conductive pillar contacts each contact pad; the pillar includes a core and a solder body, which connects the core to the respective trace across the gap. The pillar core has a non-circular cross section of a second width and a second length greater than the second width and greater than the first width.

We claim: 
     
         1 - 16 . (canceled) 
     
     
         17 . A semiconductor device comprising:
 a substrate having a first surface including conductive traces, the traces having a first length and a first width, the first width being uniform along the first length, and further a pitch to respective adjacent traces;   a semiconductor chip having a second surface including contact pads, the second surface facing the first surface spaced apart by a gap;   a conductive pillar of a height on each contact pad, the pillar including a core and a solder body connecting the core to the respective trace across the gap; and   the pillar core having a non-circular cross section having a second width and a second length greater than the second width and greater than the first width.   
     
     
         18 . The semiconductor device of  claim 17  wherein the outline of the pillar core non-circular cross section is a rectangle. 
     
     
         19 . The semiconductor device of  claim 17  wherein the outline of the pillar core non-circular cross section is an ellipse. 
     
     
         20 . The semiconductor device of  claim 17  wherein the outline of the pillar core non-circular cross section is a rectangle an oval. 
     
     
         21 . The semiconductor device of  claim 17  wherein the outline of the pillar core non-circular cross section is like a outline of a cross section of a football. 
     
     
         22 . The semiconductor device of  claim 18 , wherein the second width is equal to or less than about 1.2 times the first width. 
     
     
         23 . The semiconductor device of  claim 18 , wherein the pillar core non-circular cross section has an area at least twice the area of a circle with second width diameter. 
     
     
         24 . The semiconductor device of  claim 17 , wherein the pillar height is at least twice the second width. 
     
     
         25 . The semiconductor device of  claim 17 , wherein the pillar height is at least equal to the second length. 
     
     
         26 . The semiconductor device of  claim 17 , wherein the metal core of the pillar is made of copper. 
     
     
         27 . The semiconductor device of  claim 17 , wherein the trace pitch is equal to or smaller than twice the second width. 
     
     
         28 . The semiconductor device of  claim 17 , wherein the trace pitch is equal to or smaller than the second length. 
     
     
         29 . The semiconductor device of  claim 17 , wherein the traces include a bulk metal. 
     
     
         30 . The semiconductor device of  claim 29 , wherein the bulk metal is copper. 
     
     
         31 . The semiconductor device of  claim 29 , wherein the traces further include a metal layer covering the bulk metal, the metal layer being wettable by solder. 
     
     
         32 . The semiconductor device of  claim 31 , wherein the metal layer is a stack of a nickel layer followed by an outermost noble metal layer. 
     
     
         33 . The semiconductor device of  claim 31 , wherein the metal layer is a solder layer. 
     
     
         34 . The semiconductor device of  claim 17 , further including a polymer compound surrounding the pillars and the solder, and filling the gap between the first and the second surface.