US Patent 7816793 Apparatus for facilitating proximity communication between chips

One embodiment of the present invention provides a system for facilitating proximity communication between semiconductor chips. The system includes a base chip and a bridge chip, each of which includes an active face upon which active circuitry and signal pads reside, and a back face opposite the active face. The active face of the bridge chip is bonded to the active face of the base chip. Then, an identified portion of the active face of the bridge chip is thinned via etching and is removed by planarizing the back face of the bridge chip, thereby creating an opening in the bridge chip that exposes a portion of the active face of the base chip.