Multilayer Wiring Board Layout for Differential Crosstalk Suppression
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Solution Overview
Problem
As the wiring density in multilayer wiring boards increases, electromagnetic waves between components cause crosstalk, leading to signal interference, which existing technologies have not effectively addressed.
Innovation Solution
A multilayer wiring board design with differential wirings and ground vias arranged to form enclosures around ground vias, and eaves portions in clearance regions to reduce electromagnetic interference and maintain impedance, thereby reducing crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wiring density is increased to accommodate more differential wirings, then signal transmission capacity is improved, but electromagnetic interference and crosstalk worsen
Solution Approach 1:
The patent introduces ground vias as intermediary elements positioned between differential wiring pairs. These ground vias act as mediators that provide electromagnetic shielding and reference potential, reducing the harmful electromagnetic interference between adjacent signal lines while allowing high wiring density to be maintained.
Solution Approach 2:
The patent applies different structural configurations to different regions of the wiring board. Specifically, ground vias are strategically positioned at specific locations between differential pairs, and clearance regions are created around signal vias, providing localized electromagnetic shielding and impedance control where needed most, rather than uniformly across the entire board.
2Reliability
If ground vias are positioned between differential wirings to reduce crosstalk, then signal integrity is improved, but wiring space and layout flexibility are reduced
Solution Approach 1:
The patent segments the wiring board into distinct regions with specific functions: differential wiring regions, ground via regions, and clearance regions. This segmentation allows for systematic placement of ground vias between differential pairs without requiring complex global optimization, as each region can be designed and routed independently according to established patterns.
3Object-affected harmful factors
If clearance regions are created around signal vias to reduce interference, then electromagnetic shielding is improved, but manufacturing complexity and process steps are increased
Solution Approach 1:
The patent merges the clearance region function with the existing ground via structure. The clearance regions are formed as part of the ground via pattern definition, combining two functions (electromagnetic shielding and reference plane maintenance) into a single manufacturing process step, thereby reducing overall manufacturing complexity rather than adding separate steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively suppresses crosstalk and maintains signal integrity, enabling high-speed and accurate signal transmission in high-density wiring environments.
Implementation Method 1
the ground via being sandwiched between the first wiring and the second wiring... effectively suppresses crosstalk... reduce electromagnetic interference
Data Source
AI summary
A multilayer wiring board has a first signal layer and ground layers, and includes a first differential wiring provided in the first signal layer and including first and second wirings, a first another signal line provided on the first signal layer, a signal via extending along the stacking direction and electrically connected to the first another signal line, and a ground via extending along a stacking direction and electrically connected to the ground layers. The first differential wiring includes a first portion, a second portion continuous with the first portion, and a third portion continuous with the second portion, the first wiring being disposed between the ground via and the signal via adjacent to the ground via, the second wiring being disposed on an opposite side of the first wiring across the ground via, and the ground via being sandwiched between the first and second wirings.