Multi-chip package with pillar connection

Abstract

A semiconductor device has a substrate having a first plurality of substrate bonding pads disposed on a bonding surface thereof. A plurality of semiconductor dice is disposed on the substrate. Each die of the plurality of dice has a first plurality of die bonding pads arranged along at least one first edge thereof. A plurality of bonding pillars extends substantially vertically from the substrate bonding pads. Each bonding pillar electrically connects one of the first plurality of substrate bonding pads to a corresponding one of the first plurality of die bonding pads. A method of assembling a semiconductor device is also described.

1 . A method of assembling a semiconductor device, comprising:
 forming a plurality of substantially vertical bonding pillars on a bonding surface of a substrate in electrical connection with a first plurality of substrate bonding pads;   stacking a plurality of semiconductor dice on the bonding surface of the substrate, each of the plurality of dice having a first plurality of die bonding pads arranged along at least one first edge thereof, such that each of the first plurality of die bonding pads is in proximity of a corresponding one of the plurality of bonding pillars; and   forming an electrical connection between each of the plurality of bonding pillars and the corresponding one of the first plurality of die bonding pads.   
     
     
         2 . The method of  claim 1 , wherein:
 the bonding surface of the substrate has a second plurality of substrate bonding pads disposed thereon; and   each of the plurality of dice has a second plurality of die bonding pads arranged along at least one second edge thereof;   
       the method further comprising:
 attaching bonding wires between each of the second plurality of substrate bonding pads and a corresponding one of the second plurality of die bonding pads. 
 
     
     
         3 . The method of  claim 2 , wherein:
 forming an electrical connection between each of the plurality of bonding pillars and a corresponding one of the first plurality of die bonding pads comprises welding each of the plurality of bonding pillars to the corresponding one of the first plurality of die bonding pads.   
     
     
         4 . The method of  claim 2 , wherein:
 forming an electrical connection between each of the plurality of bonding pillars and a corresponding one of the first plurality of die bonding pads comprises connecting each of the plurality of bonding pillars to the corresponding one of the first plurality of die bonding pads using an electrically conductive epoxy.   
     
     
         5 . The method of  claim 1 , wherein:
 forming each of the plurality of substantially vertical bonding pillars comprises:
 forming a ball bond on a corresponding one of the first plurality of substrate bonding pads using a wire bonding machine; 
 forming a wire attached to the ball bond and extending generally away from the surface of the substrate; and 
 clipping the wire at a desired distance from the bonding surface of the substrate, thereby to form a bonding pillar of a desired height. 
   
     
     
         6 . The method of  claim 5 , wherein:
 forming each of the plurality of substantially vertical bonding pillars further comprises:
 forming a ball at an upper end of the wire. 
   
     
     
         7 . The method of  claim 1 , wherein:
 stacking a plurality of dice comprises positioning at least one die of the plurality of dice such that the first edge of the at least one die overhangs the bonding pillars connected to a previously stacked die.