Wafer Backside Interconnect Structure for TSV Routing

The patent transitions from direct TSV-to-bump connections in a single layer to a multi-layer interconnect structure where metal lines are routed through multiple dielectric layers. This dimensional expansion allows signals to reach locations far from TSVs by traveling through the third dimension (vertical stacking of interconnect layers), thereby improving routing ability while maintaining the large TSV pitch required for reliable bonding.

The patent introduces metal pads and metal lines as intermediary elements between the TSVs and the final bump connections. These intermediaries extend the electrical connection from the TSV location to distant locations on the substrate, solving the routing limitation while the TSVs themselves maintain their optimal large pitch spacing for reliable bonding.

The patent segments the interconnect structure into multiple functional layers: TSVs penetrating the substrate, dielectric layers providing insulation and spacing, metal pads for local connections, and metal lines for long-distance routing. This segmentation allows each layer to be optimized for its specific function while using standard semiconductor fabrication processes, maintaining manufacturing simplicity despite the increased routing capability.

By adding vertical stacking of interconnect layers above the substrate backside, the patent enables routing to distant locations without complicating the fundamental manufacturing approach. The multi-layer structure uses conventional deposition and patterning techniques applied in sequence, preserving ease of manufacture while dramatically improving routing ability.