Sacrificial Trace Layout for High-Speed EMI Absorption

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Solution Overview

Problem

Modern semiconductor packages face challenges in reducing electromagnetic interference (EMI) and electromagnetic fields (EMF) on victim traces due to high-density trace designs, which are exacerbated by the proximity of aggressor traces to the ground plane, complicating temperature and signal integrity.

Innovation Solution

Incorporating a sacrificial copper trace layer parallel to aggressor traces, positioned between the aggressor and ground plane, to absorb electromagnetic interference, thereby reducing the distance between the aggressor and ground plane and enhancing EMI and EMF absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the distance between aggressor trace and ground plane is reduced to minimize EMI, then electromagnetic interference absorption is improved, but trace separation distance is reduced making it difficult to meet temperature and signal integrity requirements

Engineering Contradiction:

Improveelectromagnetic interferenceVSAvoidtrace separation distance

Core Design Contradiction:

Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The ground plane is segmented by introducing sacrificial traces that create localized ground regions beneath aggressor traces. This segmentation allows the aggressor trace to be effectively closer to a ground reference (reducing EMI) while maintaining larger separation from victim traces through the sacrificial trace structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Sacrificial traces act as intermediary elements positioned between aggressor traces and the main ground plane. These intermediaries provide electromagnetic shielding and absorption functionality, allowing the aggressor trace to operate at lower heights without directly increasing interference to victim traces.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If trace density is increased to meet packaging requirements, then area utilization is improved, but electromagnetic interference between closely spaced traces increases

Engineering Contradiction:

Improvearea utilizationVSAvoidcross talk noise

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The sacrificial trace structure provides localized electromagnetic shielding only where needed beneath aggressor traces. This local quality enhancement allows high trace density in other areas while providing targeted EMI protection where aggressor-victim interactions occur, maintaining area efficiency without sacrificing signal integrity.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If aggressor traces are positioned closer to ground plane to reduce EMI, then electromagnetic field absorption is improved, but temperature management and signal integrity become more difficult to maintain

Engineering Contradiction:

Improveelectromagnetic field interferenceVSAvoidsignal integrity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The ground plane segmentation through sacrificial traces creates localized shielding regions that reduce EMI for aggressor traces without forcing all traces into close proximity to the ground plane. This maintains proper signal integrity and temperature characteristics for victim traces while providing EMI protection where needed.

Inventive Principle:

Principle #1Segmentation

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

This configuration effectively minimizes EMI and EMF on victim traces, allowing for closer trace spacing and improved signal integrity while accommodating PCB density and temperature requirements.

Implementation Method 1

The sacrificial trace absorbs electromagnetic signals emitted from the signal conveyed in the first trace

Methodology Applied

Scientific EffectElectromagnetic absorption: Absorption (EM radiation)

Data Source

PatentUS20250273591A1Adding sacrificial traces to aborb signal interference from high speed aggressor traces

Publication Date: 2025.08.28 SANDISK TECHNOLOGIES LLC

AI summary

A semiconductor package includes an integrated circuit having a first trace configured to convey a signal and a ground layer positioned on one side of the integrated circuit. A sacrificial trace is positioned between the ground layer and the first trace. The sacrificial trace absorbs electromagnetic signals emitted from the signal conveyed in the first trace. A method of manufacturing a semiconductor package that includes providing an integrated circuit that includes a first trace configured to convey a signal, positioning a ground layer on one side of the integrated circuit, and positioning a sacrificial trace between the ground layer and the first trace, where the sacrificial trace absorbs electromagnetic signals emitted from the signal conveyed in the first trace.