Package Substrate Shield-Stiffener for EMI and Warpage Control

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Solution Overview

Problem

Legacy microstrip implementations in package substrates fail to meet signal integrity requirements at high data transmission speeds, leading to increased substrate layers and Z-height, which are costly and time-consuming to fabricate, while also causing electromagnetic interference (EMI) and radio frequency interference (RFI) issues.

Innovation Solution

Implementing a shield or stiffener on the package substrate that serves as an EMI/RFI shield and provides mechanical stability, reducing warpage and interference by being electrically coupled to ground, thus allowing for microstrip routing with fewer layers and maintaining signal integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If legacy microstrip implementations are used in package substrates, then signal transmission can be achieved, but signal integrity deteriorates at increasing data transmission speeds and electromagnetic interference is generated

Engineering Contradiction:

Improvesignal integrityVSAvoidelectromagnetic interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an electrically conductive shield as an intermediary element positioned between the signal trace and the surrounding environment. This shield acts as a mediator that blocks electromagnetic fields from interacting with the signal trace, thereby reducing EMI and RFI while maintaining signal integrity at high data transmission speeds.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes the electrically conductive shield to convert potential harmful electromagnetic interference into a beneficial shielding effect. By strategically positioning the shield proximate to the signal trace, the conductive material creates a protective electromagnetic environment that actively counteracts EMI and RFI, turning the presence of conductive elements (which could potentially generate interference) into a protective mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If additional shielding layers are added to reduce EMI and improve signal integrity, then electromagnetic interference is reduced, but package thickness increases

Engineering Contradiction:

Improveelectromagnetic interference reductionVSAvoidpackage thickness

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent applies the shield only in specific locations where EMI and RFI are most problematic, rather than implementing a complete surrounding shield. The shield is positioned proximate to critical signal traces and die connections, providing localized protection exactly where needed. This selective placement maintains signal integrity and reduces EMI while minimizing the additional thickness required.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements partial shielding rather than complete 360-degree protection. The shield covers only the portions of the package substrate where high-frequency signal traces are present and EMI protection is most critical. This partial action approach achieves sufficient EMI reduction for high-speed signals without the excessive thickness that would result from comprehensive shielding of the entire package.

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If more substrate layers are used to accommodate signal traces, then signal routing capability is improved, but manufacturing complexity and fabrication time increase

Engineering Contradiction:

Improvesignal routing capabilityVSAvoidfabrication time

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent transitions from a planar 2D signal routing approach to a 3D spatial arrangement by positioning the electrically conductive shield vertically above or below the signal trace. This dimensional change allows the shield to provide EMI protection without requiring additional horizontal substrate layers, thereby maintaining signal routing capability while avoiding increased manufacturing complexity associated with adding more substrate layers.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 shield reduces EMI/RFI, improves signal integrity, and maintains package thickness, enabling thinner and more cost-effective fabrication with reduced lead times, suitable for high-frequency signals in mobile devices.

Implementation Method 1

the shield reduces electromagnetic interference (EMI) or radio frequency interference (RFI) transmitted or received by the conductive trace

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

the shield reduces warpage in the substrate

Methodology Applied

Scientific EffectMechanical stiffness: Elasticity

Data Source

PatentUS12604736B2Shield to reduce substrate electromagnetic interference and warpage

Publication Date: 2026.04.14 INTEL CORP

AI summary

Embodiments herein relate to systems, apparatuses, techniques, or processes for stiffeners for a surface of a package substrate, where the stiffeners provide EMI/RFI shielding for signal traces or other electrical routings within the package, and in particular for traces at a surface of the package such as microstrip routings. Other embodiments may be described and/or claimed.