EMI Shielding Structure with Surface-Treated Metal Layers
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Solution Overview
Problem
Existing electromagnetic shielding methods using metal members often fail to completely prevent electromagnetic interference (EMI) leakage on printed circuit boards, due to issues with coverage, material thickness, and coefficient of thermal expansion discrepancies, leading to performance degradation and malfunction in electronic components.
Innovation Solution
A shielding structure with surface-treated metal layers having specific surface roughness on inner surfaces is applied to surround electronic components, preventing EMI leakage by ensuring adequate adhesion and anchoring energy, and comprising a combination of physical and chemical processing methods to form uniform metal layers with controlled thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal members are used for electromagnetic shielding, then electromagnetic interference between adjacent electronic components can be prevented, but EMI leakage frequently occurs on the surface of the printed circuit board due to incomplete coverage and adhesion issues
Solution Approach 1:
The invention changes the surface parameters of the metal layer by controlling surface roughness within specific ranges (Ra 0.5-3.0 μm for outer surface, Ra 0.3-2.5 μm for inner surface). This parameter optimization improves adhesion between the metal layer and substrate while maintaining effective EMI shielding, preventing both peeling and leakage issues that occur with conventional smooth or overly rough surfaces.
Solution Approach 2:
The invention employs a composite structure consisting of a substrate and a metal layer with specific surface roughness characteristics. This composite approach combines the shielding properties of metal with the adhesive benefits of controlled surface morphology, creating a more reliable EMI shielding system than either component alone could provide.
2Length of moving object
If the metal member is made thinner to reduce device size, then space is saved, but adhesion strength decreases and blistering occurs
Solution Approach 1:
The invention optimizes the surface roughness parameters of the metal layer to compensate for reduced thickness. By controlling Ra within 0.5-3.0 μm for the outer surface and 0.3-2.5 μm for the inner surface, the adhesive strength is enhanced through increased surface area and mechanical interlocking, allowing thin metal layers to maintain strong adhesion without blistering.
3Reliability
If the metal member is made thicker to improve shielding efficiency, then EMI blocking is enhanced, but device size and weight increase
Solution Approach 1:
The invention achieves effective EMI shielding with thinner metal layers by optimizing surface roughness parameters. The controlled roughness (Ra 0.5-3.0 μm outer, Ra 0.3-2.5 μm inner) increases the effective shielding path length and improves adhesion, allowing reduced thickness while maintaining or enhancing shielding efficiency compared to conventional thick, smooth metal layers.
4Ease of manufacture
If conventional smooth metal surfaces are used, then manufacturing is simpler, but adhesion is poor and peeling occurs
Solution Approach 1:
The invention introduces controlled surface roughness (Ra 0.5-3.0 μm outer, Ra 0.3-2.5 μm inner) as an optimized manufacturing parameter. While this requires additional surface treatment steps compared to conventional smooth surfaces, it dramatically improves adhesion strength and prevents peeling, making the overall manufacturing process more reliable and reducing rework.
5Strength
If the metal layer has high surface roughness to improve adhesion, then anchoring energy increases, but shielding efficiency decreases due to non-uniform current distribution
Solution Approach 1:
The invention identifies and implements optimal surface roughness parameters (Ra 0.5-3.0 μm for outer surface, Ra 0.3-2.5 μm for inner surface) that balance adhesion and shielding requirements. This precise parameter control ensures sufficient anchoring energy for strong adhesion while maintaining surface uniformity adequate for effective EMI shielding, avoiding the pitfalls of both smooth and overly rough surfaces.
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 significantly enhances electromagnetic shielding efficiency by reducing EMI leakage, minimizing blister phenomena, and improving adhesion strength, resulting in increased reliability and performance stability of electronic components across various frequency bands.
Implementation Method 1
metal layers for shielding electromagnetic waves having surface roughness on an inner surface of a side portion and an inner surface of an upper portion
Implementation Method 2
shielding structure having surface roughness... significantly enhances electromagnetic shielding efficiency by reducing EMI leakage
Implementation Method 3
ensuring adequate adhesion and anchoring energy... improving adhesion strength
Data Source
AI summary
A structure and a device may include an electromagnetic wave generator configured to generate electromagnetic waves; a shielding structure configured to surround at least a portion of the electromagnetic wave generator; and a metal layer provided on inner surfaces of upper and side portions of the shielding structure, wherein the metal layer having a predetermined surface roughness.