Wire Bonded Stacked Chips

 

The wire bonded stacked chips method uses a wire bonding technique for the vertical interconnections. There are two variants for this approach:

• Wire bonded to an MCM substrate directly: Stacked chips are wire bonded to a planar MCM substrate using wire bonding technology as shown in Figure . This approach was used by Matra Marconi Space for a high density solid state recorder.  

    
  Figure: A vertical interconnection approach using wire bonding techniques.
  

• Wire bonded to a substrate through an IC: In this scenario, there is a mother and a daughter chip. The mother chip acts as a substrate for the daughter chip. Interconnections from the daughter chip go to pads on the surface of the mother chip substrate, as shown in Figure . Voltonic USA has used this technology in some medical applications.  

    
  Figure: (upper) A schematic diagram of two chips stacked and interconnected using wire bonding. (lower) A top view of the upper schematic diagram.