Roughened Shielding Layer for Multilayer Wiring Boards
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Solution Overview
Problem
Current multilayer wiring boards with built-in semiconductor elements face challenges in effectively suppressing electromagnetic noise, as existing shielding methods do not adequately address the issue of harmonic radiation noise and reflection, leading to incomplete suppression of electromagnetic interference.
Innovation Solution
A multilayer wiring board design featuring a concave portion with multiple insulation layers, conductive circuits, vias for electrical connection, and an electromagnetic shielding layer with a roughened surface, comprising multiple sub-layers with varying reflection and absorption losses to enhance shielding effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electromagnetic shielding layer with a smooth surface is used, then the manufacturing process is simple, but the shielding effectiveness against electromagnetic noise is insufficient
Solution Approach 1:
The patent changes the surface parameter of the electromagnetic shielding layer from smooth to rough. This surface roughening increases the absorption loss of electromagnetic waves by creating multiple reflection paths and scattering effects, thereby significantly improving shielding effectiveness without adding complex multi-layer structures
Solution Approach 2:
The patent employs a composite shielding layer structure combining a roughened surface layer with specific material composition. The roughened surface works synergistically with the base shielding material to enhance electromagnetic wave absorption and reflection, achieving superior shielding performance
2Reliability
If a single-layer electromagnetic shielding structure is used, then the manufacturing process is simple, but the absorption and reflection loss of electromagnetic waves is insufficient
Solution Approach 1:
The patent optimizes the thickness parameter of the electromagnetic shielding layer to achieve maximum absorption loss. By carefully controlling the layer thickness relative to the wavelength of electromagnetic waves, the structure achieves resonant absorption effects that significantly enhance shielding performance without requiring multiple thick layers
Solution Approach 2:
The patent applies different properties to different parts of the shielding layer. The surface is roughened while the bulk maintains specific material composition and density, creating local quality variations that optimize both absorption and reflection of electromagnetic waves at different depths
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 design significantly reduces electromagnetic interference by effectively blocking electromagnetic waves and radiation noise, allowing for the integration of diverse electronic circuits like digital, analog, and memory circuits within a compact mobile terminal, while maintaining reliable electrical connectivity and connection reliability.
Implementation Method 1
The electromagnetic shielding layer has a roughened surface and formed along one of a bottom surface and side surfaces of the concave portion in the multilayer wiring substrate
Implementation Method 2
The electromagnetic shielding layer has a roughened surface and formed along one of a bottom surface and side surfaces of the concave portion in the multilayer wiring substrate
Data Source
AI summary
A multilayer wiring board includes a multilayer wiring substrate having a concave portion which accommodates an electronic component. The multilayer wiring substrate has multiple insulation layers, multiple conductive circuits, multiple vias and an electromagnetic shielding layer. The conductive circuits are separated by the insulation layers and electrically connected through the vias. The electromagnetic shielding layer has a roughened surface and formed along one of a bottom surface and side surfaces of the concave portion in the multilayer wiring substrate.