Three-dimensional multi-chip pad array carrier

TL;DR: In this paper, a stackable three-dimensional multi-chip module (MCM) is provided whereby each level of chip carrier is interconnected to another level through reflowing of solder balls pre-bumped onto each carrier.

Abstract: A stackable three-dimensional multi-chip module (MCM) is provided whereby each level of chip carrier is interconnected to another level of chip carrier through reflowing of solder balls pre-bumped onto each carrier. Each level of chip carrier, except for the top carrier, has solder balls on both top and bottom surfaces of the substrate. Optional lids can be used to seal each device, and the lid height would serve as a natural positive stand-off between each level of carriers, giving rise to hour glass shaped solder joints which maximizes the fatigue life of the joints. Heat sinks to further enhance heat dissipation of the MCM can be easily accommodated in this stacking approach. Furthermore, each substrate is capable of carrying multiple chips, so the module incorporates planar chip density growth concurrently with the three-dimensional growth giving rise to an ultradense MCM.