US Patent 7700409 Method and system for stacking integrated circuits

A design for stacking integrated circuits is described. Some integrated circuits have multiple signal pads that are common between a top integrated circuit and a bottom integrated circuit in an integrated circuit pair. These common pads are placed symmetrically on the integrated circuit. Unique signal pads are provided independently to each integrated circuit in a stack. An optional array of solder bumps placed over a central area of the integrated circuit may be used, which provides for heat transfer through the stack. When stacking multiple pairs of integrated circuits, the top integrated circuit in the integrated circuit stack pair serves as a spacer between the first and second pair of integrated circuits.