3D IC Stack Edge Interconnects for Routing and Heat Dissipation

The patent transitions from single-sided (one-dimensional) interconnects to multi-sided (four-dimensional) interconnects by adding interconnect structures on all four sidewalls of the IC stack. This dimensional expansion enables power and signal distribution to reach all dies in the stack from multiple directions, dramatically improving distribution capability without proportionally increasing complexity.

The sidewall interconnect structures serve multiple functions simultaneously: they provide power distribution, signal routing, and thermal management pathways. Each sidewall interconnect layer can carry different signals and power levels, making the interconnect system highly versatile and adaptable to various die configurations.

The patent adds thermal management pathways in the lateral dimensions by implementing thermal vias and heat dissipation structures on all four sidewalls. This transforms the thermal management from a single-direction (bottom-to-top) approach to a multi-directional approach, enabling heat to escape through multiple pathways and significantly improving heat dissipation capability.

The patent introduces thermal vias and heat dissipation layers as intermediary structures between the active dies and the heat sink. These intermediary thermal management structures facilitate efficient heat transfer from the densely packed dies through the sidewalls to external cooling systems, acting as a bridge between the heat-generating components and the thermal management system.

The patent divides the interconnect system into multiple independent sidewall interconnect layers, each handling specific power or signal routing functions. This segmentation allows each layer to be optimized independently and simplifies the overall design by breaking down the complex multi-sided interconnect problem into manageable modular components that can be stacked and combined systematically.

The patent applies different interconnect configurations to different sidewalls based on local requirements. Each sidewall can have customized interconnect densities, material compositions, and routing patterns optimized for its specific functional needs, allowing the system to achieve high versatility without uniformly increasing complexity across the entire structure.

The patent incorporates interconnect structures on all four sidewalls during the initial wafer fabrication process, before the IC stack is assembled. This preliminary formation of sidewall interconnects eliminates the need for complex post-assembly wiring operations and allows for precise alignment and integration. The interconnect structures are pre-configured with appropriate materials and geometries to match the specific die stack requirements.

The patent utilizes standard semiconductor manufacturing parameters and materials that can be adjusted to achieve different interconnect configurations. By changing parameters such as metal layer thickness, via dimensions, and material composition within existing process capabilities, the system achieves high design flexibility without requiring fundamentally new manufacturing techniques or equipment.