Conformal EM Shielding Layer for Semiconductor Packages
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Solution Overview
Problem
Conventional electromagnetic (EM) shielding structures for semiconductor packages are not cost-effective and occupy excessive surface area, failing to provide adequate shielding against electromagnetic interference (EMI).
Innovation Solution
A conformal EM shielding structure is implemented, where an EM shielding layer is applied directly to the sidewalls of semiconductor packages, covering the mold compound and exposed EM shielding contact structures, without occupying additional substrate surface area, and is electrically connected to a ground layer through conductive via holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a prefabricated metal lid is mounted on the substrate to provide EM shielding, then the EM shielding effect is achieved, but the surface area occupied increases and cost effectiveness decreases
Solution Approach 1:
The patent transitions from a planar EM shielding approach (metal lid on substrate surface) to a conformal three-dimensional shielding structure that follows the contours of the substrate and components. The shielding layer is applied conformally to vertical sidewalls and surfaces, utilizing the third dimension (height/depth) to provide EM shielding without occupying additional planar surface area. This dimensional transition allows the shielding to wrap around components and cover exposed surfaces while maintaining the same footprint.
2Reliability
If a prefabricated metal lid is used for EM shielding, then shielding is provided, but manufacturing cost increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the shielding material application process. Instead of using discrete prefabricated metal lids requiring mechanical assembly, the shielding is applied as a conformal coating layer through deposition processes. The material transitions from bulk metal pieces to thin conformal films, changing parameters such as material thickness, application method, and structural form. This enables integration with standard semiconductor manufacturing processes, reducing assembly steps and improving cost effectiveness.
3Reliability
If EM shielding is implemented with conventional structures, then some shielding is provided, but the shielding adequacy is insufficient
Solution Approach 1:
The conformal EM shielding structure serves multiple functions simultaneously: it provides electromagnetic shielding, electrically connects to ground through via holes, and conformally covers complex three-dimensional surfaces including vertical sidewalls. The single continuous shielding layer integrates these functions, eliminating the need for separate shielding components, ground connections, and surface coverage elements. This multi-functionality approach improves shielding adequacy while avoiding the complexity of assembling multiple discrete shielding parts.
Data Source
AI summary
A semiconductor package includes a substrate having a front side, a bottom side, and a sidewall along a perimeter of the substrate, a plurality of solder pads on the bottom side, at least one EM shielding contact structure on the bottom side and partially exposed on the sidewall, a semiconductor device mounted on the front side, a mold compound on the front side and covering the semiconductor device, and an EM shielding layer conformally covering the mold compound and the sidewall. The EM shielding layer is in direct contact with the exposed portion of the EM shielding contact structure on the sidewall.