Multi-Layer Circuit Board Ground Trace Configuration
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Solution Overview
Problem
Rigid circuit boards with thick core dielectric layers increase the distance between signal traces and ground planes, leading to inaccurate impedance and signal quality degradation due to ineffective ground plane reference and cross-talk issues.
Innovation Solution
The circuit board design includes multiple patterned conductive layers with increased ground traces near signal traces, and ground conductive vias connecting these traces to a ground plane, enhancing signal transmission quality by providing a better ground reference effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the core dielectric layer thickness is increased to provide sufficient structural strength, then the structural strength is improved, but the distance between signal traces and ground plane increases resulting in ineffective ground plane reference and inaccurate impedance
Solution Approach 1:
The patent transitions from relying solely on the distant ground plane (vertical dimension reference) to introducing ground traces in the horizontal dimension on the same layer as signal traces. This dimensional shift provides a nearby reference that is effective despite the thick core dielectric layer, resolving the contradiction between structural strength and impedance accuracy.
Solution Approach 2:
Ground traces act as an intermediary element between the signal traces and the distant ground plane. These intermediary ground traces provide immediate reference for signal traces, compensating for the ineffective reference from the distant ground plane caused by the thick core dielectric layer.
2Strength
If the core dielectric layer thickness is increased to provide sufficient structural strength, then the structural strength is improved, but cross-talk caused by radiation adjacent to signal traces affects signal transmission quality
Solution Approach 1:
Ground traces serve as intermediary shielding elements positioned between adjacent signal traces. These intermediary ground traces intercept and divert electromagnetic radiation, preventing cross-talk between signal traces while maintaining the thick core dielectric layer for structural strength.
Solution Approach 2:
The patent converts the potentially harmful electromagnetic radiation that causes cross-talk into a beneficial shielding effect by strategically placing ground traces. The ground traces absorb and redirect the radiation, transforming the harmful interference into a protective mechanism that improves signal transmission quality.
3Reliability
If ground traces are increased in the vicinity of signal traces to obtain fine reference effect, then signal transmission quality is improved, but device complexity increases
Solution Approach 1:
The ground traces are designed with homogeneous characteristics - using the same trace width, spacing, and material properties as the signal traces. This homogeneity simplifies the manufacturing process and design rules, reducing device complexity while maintaining improved signal transmission quality through better reference effects.
Data Source
AI summary
A circuit board including a first patterned conductive layer and a second patterned conductive layer isolated from the first patterned conductive layer is provided. The first patterned conductive layer has first signal traces and first ground traces. The second patterned conductive layer has second signal traces and second ground traces. An orthogonal projection of the second ground trace on the first patterned conductive layer partially overlaps at least one of the first signal traces. An orthogonal projection of the first ground trace on the second patterned conductive layer partially overlaps at least one of the second signal traces. An electronic assembly including the afore-described circuit board and a chip package connected thereto is also provided.