Composite EMI Shielding With Conductive Spheres for Semiconductor Packages
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Solution Overview
Problem
Conventional electromagnetic shielding materials for semiconductor devices, particularly in high-frequency applications, face challenges due to oxidation issues with copper and high costs associated with metal deposition processes, which affect the effectiveness and efficiency of electromagnetic interference (EMI) and radio frequency interference (RFI) reduction.
Innovation Solution
A shielding material comprising conductive spheres with insulating cores embedded in a matrix is applied over semiconductor devices, utilizing conductive ink or polymers like PMMA or PET, which effectively scatter and absorb EMI noise waves through reflection and absorption, reducing interference while minimizing oxidation risks and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If copper is used as shielding material, then cost-effectiveness and electrical conductivity are improved, but oxidation resistance deteriorates
Solution Approach 1:
The patent uses composite shielding material comprising conductive spheres (metal particles) embedded in a polymer matrix. This composite structure combines the electrical conductivity of metal particles with the oxidation resistance and structural stability of the polymer matrix, resolving the contradiction between cost-effectiveness and oxidation resistance.
2Reliability
If metal deposition process is used for shielding, then EMI shielding effectiveness is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent replaces expensive metal deposition processes with a cost-effective polymer-based shielding material that can be applied through simpler coating methods. The polymer matrix with conductive fillers provides adequate shielding effectiveness at lower material and processing costs.
Solution Approach 2:
The patent changes the physical and chemical parameters of the shielding material from pure metal deposits to polymer composites with controlled conductive filler content. This parameter change allows achieving acceptable shielding effectiveness through less expensive manufacturing processes while maintaining functional performance.
3Reliability
If conventional shielding material is used, then EMI shielding is achieved, but throughput and production efficiency decrease
Solution Approach 1:
The patent replaces complex metal deposition systems with simpler coating processes for polymer-based shielding material. The polymer composite can be applied through spray coating, dip coating, or lamination methods, which are faster and more suitable for high-volume production compared to vacuum deposition techniques.
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 shielding material significantly reduces EMI and RFI interference by reflecting and absorbing noise waves, enhancing the operational stability and reducing manufacturing costs by using a cost-effective, oxidation-resistant approach.
Implementation Method 1
The shielding material reduces or inhibits electromagnetic interference (EMI), radio frequency interference (RFI), EMI noise waves
Implementation Method 2
The shielding material reduces or inhibits electromagnetic interference (EMI), radio frequency interference (RFI), EMI noise waves
Data Source
AI summary
A semiconductor device has a substrate and an electrical component disposed over the substrate. An encapsulant is deposited over the electrical component and substrate. A shielding material, containing a plurality of spheres embedded in a matrix, is formed on the encapsulant. The shielding material 144 can be formed by spray coating, printing, liquid flow, or droplets. The spheres can have a curved or angled shape, e.g., circular, oval, or many flat or curved surfaces joining as a globe. The spheres each have a shell formed over a core. The shell can be a conductive material, while the core is an insulating material. Alternatively, the shell can be an insulating material, while the core is a conductive material. The shielding material scatters electromagnetic interference noise waves by reflection off the shell of the spheres. The shielding material can absorb electromagnetic interference noise waves into the core of the spheres.