Dual-Layer Electromagnetic Shield for IC Package EMI Reduction
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Solution Overview
Problem
Existing electromagnetic shields for integrated circuit packages face challenges in achieving high shielding effectiveness while maintaining a small form factor, as conventional sputtering processes often result in reduced effectiveness and difficulties in achieving thin layers of high permeability materials.
Innovation Solution
The implementation of a dual-shield structure, where one shield is a high permeability material and the other is a high conductivity material, layered over a mold that partially surrounds the electronic components, enhancing electromagnetic interference reduction without increasing the package height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single-layer electromagnetic shield is used to maintain small form factor, then the package height is reduced, but the shielding effectiveness is compromised
Solution Approach 1:
The electromagnetic shield is segmented into multiple functional layers: a first shield layer (e.g., copper or aluminum) for blocking electric fields and high-frequency electromagnetic waves, and a second shield layer (e.g., mu-metal or permalloy) for shielding magnetic fields and low-frequency electromagnetic interference. This segmentation allows each layer to specialize in different frequency ranges and field types, achieving comprehensive shielding while maintaining compact thickness
Solution Approach 2:
The shield employs composite material construction by combining dissimilar materials with complementary properties - high-conductivity materials (copper, aluminum) paired with high-permeability materials (mu-metal, permalloy). This composite approach creates a multi-functional shield structure that addresses both electric and magnetic field interference across wide frequency ranges without proportionally increasing package height
2Volume of moving object
If sputtering process is used to reduce shield thickness, then the form factor is improved, but the shielding effectiveness is reduced
Solution Approach 1:
The patent optimizes shield parameters by carefully controlling layer thicknesses, material compositions, and stacking sequences. By adjusting these parameters, the shield achieves maximum shielding effectiveness per unit thickness, allowing thin-layer construction through sputtering or other deposition methods while maintaining or improving overall shielding performance compared to conventional single-layer thicker shields
Solution Approach 2:
The multi-layer composite structure compensates for the reduced thickness of individual sputtered layers. Each thin layer contributes specific shielding functions, and their combined effect provides superior overall shielding performance that would not be achievable with a single thin layer, thus maintaining effectiveness while enabling thin-fabrication processes like sputtering
3Object-affected harmful factors
If high permeability material is used for magnetic shielding, then the magnetic field shielding is improved, but the layer thickness must be increased
Solution Approach 1:
The shield structure segments magnetic shielding function from electric field shielding by using separate layers: high-permeability materials (mu-metal, permalloy) are dedicated to magnetic field and low-frequency EMI shielding, while high-conductivity materials handle electric field and high-frequency shielding. This segmentation allows the high-permeability layer to be optimized for magnetic shielding efficiency without being burdened by the thickness requirements for other shielding functions
Solution Approach 2:
The composite structure pairs high-permeability materials with high-conductivity materials in a multi-layer configuration. This combination allows the high-permeability layer to achieve effective magnetic shielding at reduced thickness because the adjacent high-conductivity layers provide complementary shielding for other frequency ranges, creating a synergistic effect that reduces the overall thickness burden on any single material layer
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 provides improved shielding effectiveness across a wide frequency range (1 MHz-12 GHz), with high permeability shields contributing at lower frequencies and high conductivity shields contributing at higher frequencies, while maintaining a compact form factor.
Implementation Method 1
one of the first shield or the second shield is a high permeability shield
Implementation Method 2
One of the first shield or the second shield is a high permeability shield and the remaining first or second shield is a high conductivity shield
Implementation Method 3
the remaining first or second shield is a high conductivity shield relative to the high permeability shield
Implementation Method 4
high conductivity shields contributing at higher frequencies
Data Source
AI summary
Some features pertain to a package that includes an enhanced electromagnetic shield. The package includes a substrate, an electronic component coupled to the substrate, and a mold partially surrounding the electronic component. The package further includes a first shield over the mold, and a second shield over the first shield. One of the first shield or the second shield is a high permeability shield and the remaining first or second shield is a high conductivity shield relative to the high permeability shield.