Semiconductor Shielding Layer Segmentation for Low-Frequency EMI
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Solution Overview
Problem
Existing semiconductor packages face challenges in effectively shielding low-frequency electromagnetic interference due to the need for thicker shielding layers, which increase manufacturing costs and often result in poor bonding strength, leading to failure in peeling tests.
Innovation Solution
A two-layer shielding structure comprising an adhesive layer with a conductive material and a base layer, where the adhesive layer acts as a buffer to improve adhesion and bonding strength, using spray coating to form a thicker layer for better low-frequency electromagnetic interference shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thicker shielding layer is used to block low frequency electromagnetic interference, then shielding effectiveness is improved, but manufacturing cost increases due to increased manufacturing time
Solution Approach 1:
The shielding layer is divided into two separate layers: a first shielding layer with thickness of 5-20 μm and a second shielding layer with thickness of 20-40 μm. This segmentation allows each layer to be optimized for different functions - the first layer provides initial shielding and the second layer enhances low-frequency shielding effectiveness, achieving the required 30 dB shielding at 10 MHz while controlling manufacturing time
Solution Approach 2:
The patent specifies precise thickness parameters for each shielding layer (first layer: 5-20 μm, second layer: 20-40 μm) to optimize the balance between shielding effectiveness and manufacturing efficiency. These parameter controls ensure adequate low-frequency shielding without requiring excessive thickness that would prolong manufacturing
2Object-affected harmful factors
If a thicker shielding layer is used to block low frequency electromagnetic interference, then shielding effectiveness is improved, but bonding strength deteriorates
Solution Approach 1:
The shielding structure is segmented into two layers with different thicknesses and material compositions. The first shielding layer (5-20 μm) is positioned closer to the semiconductor device providing initial protection, while the second shielding layer (20-40 μm) provides enhanced low-frequency shielding. This segmentation allows optimization of bonding strength at the interface while achieving required shielding effectiveness
Solution Approach 2:
The patent employs composite material structure where the shielding layer comprises multiple layers with different material compositions. The first shielding layer may use different materials than the second shielding layer, allowing optimization of adhesion properties in the first layer for bonding strength while the second layer focuses on shielding effectiveness, thus resolving the contradiction between thickness and bonding strength
3Object-affected harmful factors
If a material with low volume resistivity is used for the shielding layer, then shielding effectiveness is improved, but adhesion to molding compound deteriorates
Solution Approach 1:
The shielding function is segmented across two layers, allowing the first shielding layer to be optimized for adhesion to the molding compound while the second shielding layer is optimized for shielding effectiveness. This segmentation enables use of materials with appropriate properties in each layer without compromise
Solution Approach 2:
Different material properties are assigned to different locations in the shielding structure. The first shielding layer (closer to molding compound) uses materials optimized for adhesion, while the second shielding layer (outer layer) uses materials optimized for low volume resistivity and shielding effectiveness. This local quality differentiation resolves the contradiction between adhesion and shielding performance
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 enhances bonding strength and shielding effectiveness, allowing the semiconductor package to pass the peeling test class of 3B and achieve a shielding effectiveness of at least 30 dB, while reducing manufacturing costs compared to traditional sputtering processes.
Implementation Method 1
The adhesive layer has a conductive material with less shrinkage and serves as a buffer layer
Implementation Method 2
A comparative method of forming a shielding layer for blocking electromagnetic interference with low frequency on a molding compound is spray coating
Data Source
AI summary
A semiconductor package device includes a substrate, an insulation layer disposed on the substrate, and a shielding layer. The shielding layer includes an adhesive layer and a base layer. The adhesive layer is disposed between the base layer and the insulation layer. The adhesive layer and the base layer include a filler including at least a resin. The shielding layer passes a peeling test class of at least 3B of a cross-cut method and the shielding effectiveness of the shielding layer is at least or equal to 30 dB.