Chip stack structures that implement two-phase cooling with radial flow

A package structure, comprising:

• a chip stack disposed on a substrate;
• and
• a package lid which covers and encloses the chip stack and contacts the substrate around a periphery of the chip stack to define a peripheral output manifold region within an interior region of the package lid which surrounds the periphery of the chip stack;
• wherein the chip stack comprises;
• a plurality of conjoined chips;
• a central inlet manifold formed through a central region of the chip stack, the central inlet manifold comprising a plurality of inlet nozzles to feed liquid coolant from the central inlet manifold into flow cavities formed between adjacent conjoined chips in the chip stack;
• and
• a peripheral outlet manifold formed by output ports of the flow cavities around a periphery of the chip stack to output heated liquid and vapor which exits from the flow cavities into the peripheral output manifold region within the interior region of the package lid:
• and
• wherein the package lid comprises;
• a central inlet that is aligned to the central inlet manifold of the chip stack to supply liquid coolant to the central inlet manifold;
• and
• a peripheral liquid-vapor outlet which is aligned to the peripheral output manifold region within the interior region of the package lid and which collects the heated liquid and vapor that flows into the peripheral outlet manifold region within the interior region of the package lid.