Conformal Shielding Inspection via Exposed Conductive Structures
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Solution Overview
Problem
Conformal shielding in electronic modules often suffers from substrate cutting failures, uneven shielding layer thickness, and improper connections, leading to poor EMI shielding performance, requiring expensive X-ray scanners or destructive testing for quality inspection.
Innovation Solution
A package structure with conformal shielding featuring a substrate with inner grounding structures and independent conducting structures exposed to the outside, electrically connected to a conductive shielding layer, allowing for EMI shielding performance inspection using a simple resistance meter without X-ray scanners or destructive testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If X-ray scanning or destructive cross-sectional inspection is used to inspect shielding performance, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential inspection function from complex X-ray scanning equipment by creating a simplified resistance measurement system. Independent conducting structures are exposed through opening portions in the molding compound, allowing direct electrical connection points to be accessed for resistance measurement, thereby eliminating the need for expensive imaging equipment while maintaining inspection capability
Solution Approach 2:
The patent replaces expensive, complex X-ray scanning equipment with simple, inexpensive resistance meters for inspection purposes. The independent conducting structures serve as disposable or sacrificial elements that enable easy measurement without requiring sophisticated equipment, significantly reducing inspection costs and device complexity
2Measurement precision
If destructive cross-sectional inspection is used, then measurement precision is improved, but loss of substance increases
Solution Approach 1:
The independent conducting structures serve dual purposes: they are integral parts of the shielding structure during operation and simultaneously serve as accessible test points for inspection. This self-service approach allows the structure to provide its own inspection access points, eliminating the need for destructive cross-sectional cutting and preventing waste of finished products
Solution Approach 2:
The independent conducting structures are pre-formed and exposed through opening portions in the molding compound before final inspection. This preliminary preparation of accessible test points enables non-destructive measurement, avoiding the need to destroy finished products for quality verification and preventing material waste
3Manufacturing precision
If conformal shielding is applied without independent conducting structures, then manufacturing precision requirements are reduced, but reliability deteriorates
Solution Approach 1:
Independent conducting structures are formed and positioned in advance during substrate fabrication, providing predetermined connection points for the conformal shielding layer. These pre-established structures ensure reliable electrical connection even when the molding compound thickness varies, maintaining shielding effectiveness without requiring extremely precise manufacturing control
Solution Approach 2:
The independent conducting structures act as intermediary elements between the inner grounding structures and the conformal shielding layer. They provide stable, accessible connection points that mediate the electrical connection, ensuring reliable EMI shielding performance even when direct connection between the shielding layer and grounding structures is compromised by manufacturing variations
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
Enables accurate and cost-effective inspection of EMI shielding performance by measuring resistance values between independent conducting structures and the conductive shielding layer, identifying defects and ensuring effective electromagnetic interference protection.
Implementation Method 1
a conductive shielding layer covering the molding compound... to protect the circuits of the module against external electromagnetic noises
Implementation Method 2
measuring the resistance value between one independent conducting structure and the conductive shielding layer
Data Source
AI summary
A package structure with conformal shielding includes a substrate providing electrically connected inner grounding structures, a chip module mounted on the substrate, a molding compound covering the chip module and one surface of the substrate, and a conductive shielding layer covering the molding compound and the lateral sides of the substrate, and electrically connected with a part of the inner grounding structures. The substrate further provides one or multiple independent conductive structures electrically connected with the conductive shielding layer and exposed to the outside. By measuring the resistance value between one independent conductive structure and the conductive shielding layer or another independent conductive structure or one ground contact and then comparing the measured resistance value with a predetermined reference value, the EMI shielding performance of the package structure is determined.