3D Sub-THz RF Die Packaging With TDVs and Fine-Pitch Interconnects

The patent transitions from conventional planar packaging to a three-dimensional stacked architecture with multiple IC dies arranged in vertical layers. This dimensional change enables significantly higher circuit integration density by utilizing the vertical dimension, allowing RF and analog circuitry to be integrated across multiple stacked dies rather than confined to a single planar substrate.

The patent divides the integrated circuit into multiple separate IC dies that are stacked vertically. Each die can be optimized for specific functions (RF circuitry, analog circuitry, digital processing), allowing independent fabrication and optimization. The segmentation enables complex circuit integration by distributing different circuit blocks across multiple dies while maintaining high density through vertical stacking.

By segmenting the circuit into multiple independent IC dies, each die can be manufactured using standard semiconductor fabrication processes optimized for its specific function. This segmentation allows different dies to be fabricated in different fabs or using different process nodes, then stacked and interconnected using established packaging techniques such as flip-chip bonding or wire bonding, thereby managing manufacturing complexity.

The patent employs universal interconnection interfaces and standardized packaging techniques that can be applied across different die combinations. The stacked die architecture uses common bonding methods, substrate technologies, and interconnect structures that are already widely used in the industry, making the manufacturing process adaptable and scalable rather than requiring entirely new manufacturing capabilities.

The stacked die architecture provides multiple thermal management pathways by utilizing the vertical dimension. Heat can be dissipated through thermal vias and heat sinks attached to different faces of the stacked structure, rather than relying solely on planar heat spreading. This three-dimensional thermal management approach enables more efficient heat removal from high-power RF and analog circuitry.

The patent introduces thermal interface materials, thermal vias, and heat spreader structures as intermediary elements between the IC dies and the external environment. These thermal intermediaries facilitate efficient heat transfer from the densely packed circuitry through the stacked die structure to external heat sinks, managing thermal loads without requiring fundamental changes to the circuit design.