SiP Shielding Structure With Ground-Hole Faraday Cage
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Solution Overview
Problem
Current system-in-package (SiP) technologies experience inadequate electromagnetic shielding due to suboptimal grounding, leading to poor electromagnetic interference (EMI) protection in mobile devices.
Innovation Solution
A shielding structure for SiP is introduced, featuring a substrate with a device on one surface and a second ground plane surrounding the edge, along with multiple stacked first ground planes and strategically arranged ground holes to reduce ground resistance and enhance grounding, forming a Faraday cage for improved electromagnetic shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple grounding structure is used in SiP, then device integration is improved, but electromagnetic shielding effect deteriorates
Solution Approach 1:
The grounding structure is segmented into multiple components: first ground planes at different heights, second ground plane on the bottom surface, and multiple ground holes distributed throughout the substrate. This segmentation allows each component to contribute to shielding while maintaining overall integration, resolving the contradiction between simple structure and effective shielding.
Solution Approach 2:
The grounding structure transitions from a two-dimensional plane to a three-dimensional configuration with ground planes at multiple heights (first ground planes embedded in substrate, second ground plane on bottom surface) and vertical ground holes connecting them. This dimensional expansion improves shielding effectiveness without significantly increasing device footprint.
2Ease of manufacture
If ground holes are sparsely arranged in the substrate, then manufacturing complexity is reduced, but electromagnetic shielding effect deteriorates
Solution Approach 1:
Ground holes are strategically arranged in specific regions where electromagnetic shielding is most needed, particularly around the periphery of the substrate and connecting critical ground planes. This localized densification achieves effective shielding while avoiding uniform complexity throughout the entire structure.
Solution Approach 2:
The ground holes are pre-positioned and pre-formed in the substrate before final assembly, with their locations optimized in advance to create effective Faraday cage structures. This preliminary arrangement ensures shielding effectiveness is built-in during manufacturing rather than requiring complex post-processing.
3Reliability
If the shield layer is extended to the substrate, then electromagnetic shielding effect is improved, but ground resistance increases
Solution Approach 1:
The connection between shield layer and ground planes is segmented into multiple parallel paths through numerous ground holes distributed across the substrate. This segmentation creates redundant conduction paths, reducing overall ground resistance while maintaining the extended shield structure for effective electromagnetic shielding.
Solution Approach 2:
Multiple ground planes (first ground planes at different heights and second ground plane on bottom surface) are merged into a unified grounding system through vertical ground holes, creating a low-resistance network that collectively supports the extended shield layer while minimizing ground resistance.
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 proposed structure significantly enhances electromagnetic shielding effectiveness by reducing ground resistance and preventing EMI at the substrate's bottom, forming a robust Faraday cage for effective signal interference protection.
Implementation Method 1
A spacing between adjacent ground holes at a same layer is less than a specified distance, so that the ground holes can form a good Faraday cage, to improve an electromagnetic shielding effect of the shield layer
Implementation Method 2
a part that extends to the substrate is electrically connected to the first ground plane for grounding. To reduce a ground resistance, a plurality of ground holes are further disposed in the substrate
Data Source
AI summary
A shielding structure for a system-in-package includes a substrate having stacked first ground planes in the substrate, a second ground plane on a surface of the substrate, and a ground pad arranged along an edge of the substrate disposed on the second ground plane. In addition, ground holes disposed in the substrate electrically couple the adjacent ground planes. The ground holes are arranged in a ring around a board body and spacing between the adjacent ground holes is less than a specified distance in an arrangement that defines a Faraday cage. A device is disposed on the opposing surface of the substrate and a package layer is disposed on the device.