Die Interconnect Ground Plane Layout for Crosstalk-Limited Bump Fields
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Solution Overview
Problem
Current semiconductor devices face challenges with lower substrate routing density compared to chip-level routing, leading to increased product size, cost, and performance limitations due to limited bandwidth and high crosstalk in interconnect structures.
Innovation Solution
Incorporating an interconnect structure with non-uniform ground bump placement, routing layer switching, and signal trace offset to reduce crosstalk and increase routing density, enabling higher bandwidth and efficient die-to-die I/O signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If substrate routing density is increased to match chip-level routing density, then bandwidth and routing capacity are improved, but crosstalk and signal interference increase
Solution Approach 1:
The patent applies local quality by implementing non-uniform ground bump placement where the density and distribution of ground bumps vary across different regions of the interconnect structure. Specifically, ground bumps are placed more densely in regions with higher signal routing density and spaced more sparsely in regions with lower routing density, optimizing both crosstalk reduction and routing capacity locally throughout the substrate.
Solution Approach 2:
The patent employs asymmetry by deliberately creating an asymmetric distribution of ground bumps rather than using a uniform grid pattern. The ground bump placement is asymmetric with respect to signal traces, with ground bumps positioned preferentially on one side of signal pairs or in specific geometric arrangements that break symmetry to minimize electromagnetic coupling and crosstalk between adjacent signal paths.
2Ease of manufacture
If ground bumps are placed uniformly across the interconnect structure, then manufacturing simplicity is maintained, but crosstalk reduction effectiveness is limited
Solution Approach 1:
The patent transitions from uniform to non-uniform ground bump placement, where local variations in ground bump density and positioning are implemented based on the specific routing requirements of different regions. This allows manufacturing processes to remain relatively simple while achieving superior crosstalk reduction through strategically placed ground bumps in high-interference areas.
3Length of moving object
If signal traces are routed directly over bump fields, then routing length is reduced, but crosstalk and signal integrity deteriorate
Solution Approach 1:
The patent introduces ground bumps as intermediary elements positioned between signal traces and the bump field. These ground bumps act as electromagnetic shields that mediate the interaction between signal paths and underlying bumps, reducing direct coupling and crosstalk while allowing signal traces to maintain relatively short routing lengths by still passing over the bump field region.
4Object-affected harmful factors
If routing layer switching is implemented to reduce crosstalk, then signal integrity is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the interconnect structure into distinct routing regions with different layer configurations. Signal traces are routed on different metal layers in different regions of the substrate, with layer switching implemented at specific transition points. This segmented approach reduces crosstalk by separating signal paths in the vertical dimension while maintaining manufacturing feasibility through localized layer transitions.
Data Source
AI summary
Generally discussed herein are systems, devices, and methods to reduce crosstalk interference. An interconnect structure can include a first metal layer, a second metal layer, a third metal layer, the first metal layer closer to the first and second dies than the second and third metal layers, the first metal layer including a ground plane within a footprint of a bump field of the interconnect structure and signal traces outside the footprint of the bump field.