Localized IC Shielding With Conductive Epoxy Ground Path
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Solution Overview
Problem
Conventional EMI shielding solutions for RF modules do not provide sufficient localized protection and grounding for IC components, leading to inadequate attenuation of electromagnetic interference.
Innovation Solution
A method involving a conductive epoxy layer deposited on the IC component, encapsulated in mold compound, and covered with a conformal metal shield to create a ground path, which includes applying a conformal metal shield over the mold compound to form a path from the semiconductor die to a ground reference, using materials like aluminum, copper, nickel, iron, or zinc to attenuate RF signals in specific frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a compartment shield is used to protect the entire package, then EMI protection is provided, but sufficient localized protection and grounding of IC components is not achieved
Solution Approach 1:
The patent applies local quality by transitioning from a general compartment shield to localized EMI shields positioned specifically over IC components. The conformal shield is applied only to the top surface of the mold compound directly above the IC component, creating localized protection zones rather than universal shielding. This ensures that EMI protection is concentrated where it is most needed - at the component level - rather than uniformly across the entire package.
Solution Approach 2:
The patent segments the shielding function by dividing the EMI protection into discrete localized shields for individual IC components rather than a single comprehensive compartment shield. Each IC component receives its own conformal shield application, creating modular, component-specific protection zones that can be independently optimized for grounding and shielding effectiveness.
2Object-affected harmful factors
If conventional EMI shielding is applied, then some protection is provided, but adequate attenuation of RF signals in specific frequency bands is not achieved
Solution Approach 1:
The patent applies parameter changes by modifying the electrical properties of the mold compound through infusion of conductive particles or fibers. This changes the electromagnetic parameters of the molding compound, enabling it to attenuate RF signals in specific frequency bands (such as 5G bands). The conductive infusion transforms the electrically insulating mold compound into an electromagnetically active material that provides frequency-selective attenuation.
3Object-affected harmful factors
If EMI shielding structures are added to the package, then protection is improved, but device complexity increases
Solution Approach 1:
The patent merges the EMI shielding function with the existing mold compound encapsulation process. Instead of adding separate shielding structures, the conformal shield is applied directly to the mold compound surface, and the shielding particles are infused during the molding process. This integration combines structural encapsulation and EMI protection into a single unified component, eliminating the need for separate shielding structures and reducing overall device complexity.
Solution Approach 2:
The patent makes the mold compound multi-functional by infusing it with conductive particles, enabling it to simultaneously serve as structural encapsulation, mechanical protection, and EMI shielding. The mold compound transitions from a single-function structural material to a multi-functional material that provides both mechanical support and electromagnetic protection, eliminating the need for additional dedicated shielding components.
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 solution effectively attenuates RF signals causing electromagnetic interference by at least 5 dB in the n77, n78, or n79 New Radio frequency bands, providing localized and efficient EMI shielding without increasing the module's size or cost.
Implementation Method 1
The conformal metal shield and the conductive adhesive layer forming a path from the semiconductor die to a ground reference... configured to attenuate radio frequency signals in the n77, n78, or n79 New Radio frequency bands
Data Source
AI summary
Disclosed is a localized shield to protect integrated circuit (IC) components within a package module from electromagnetic interference (EMI). Conventional EMI shielding solutions, such as a compartment shield, protect an entire package but do not provide localized protection or grounding of IC components. To construct the EMI shield disclosed herein, a layer of conductive epoxy is deposited on an upper conductive surface of the IC component, then the component is encapsulated in mold compound. Excess mold compound is ground down to expose the epoxy layer, and a conformal shield layer is applied over the mold compound such that the conductive epoxy layer forms a ground path between the conformal shield and the conductive surface of the IC component.