imec proposes vertical DRAM stacking above GPU with cooling cavities

Researchers at imec published a study of a 3D memory architecture that rotates DRAM dies vertically above a GPU with cooling cavities between them, as an alternative to 2.5D HBM and direct-stacked HBM-on-GPU. Package-level thermal simulations covered stack height, memory capacity and organization, cavity materials, stack orientation, mold insertion and a distributed memory-controller/NoC tier.

• DRAM dies are rotated vertically above the GPU instead of 2.5D HBM
• Cooling cavities sit between the stacked dies
• Simulations covered stack height, capacity and orientation
• A separate memory-controller/NoC tier was evaluated