Interposer EMI Shielding for PCB Miniaturization
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Solution Overview
Problem
As electronic devices become more functional and operate at higher frequencies, they face challenges with electromagnetic interference (EMI), which can lead to abnormal device operation. Additionally, the use of shield cans to mitigate EMI complicates the miniaturization of substrates and increases component mounting area requirements.
Innovation Solution
The implementation of an electronic device design that incorporates an interposer surrounding circuit components on a printed circuit board. The interposer features through holes electrically connected to the ground, with conductive and non-conductive regions on its surfaces to effectively manage electromagnetic noise without the need for a shield can.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield can is used to prevent electromagnetic interference, then EMI protection is improved, but the substrate area and device size increase
Solution Approach 1:
The shield can structure is segmented into multiple functional layers: a ground plane layer, an interposer layer with through-holes, and a signal layer. This segmentation allows the EMI shielding function to be distributed across multiple thin layers rather than requiring a single thick shield can, thereby reducing the overall substrate area while maintaining EMI protection effectiveness.
Solution Approach 2:
The solution transitions from a three-dimensional shield can structure to a planar multi-layer PCB structure. By utilizing the vertical dimension of the PCB layers and creating through-holes that extend through the interposer, the EMI shielding function is achieved in a two-dimensional plane, significantly reducing the footprint area required for the same level of protection.
2Object-affected harmful factors
If a shield can is used to cover electronic components, then electromagnetic interference is reduced, but component mounting area increases
Solution Approach 1:
The EMI shielding function is merged with the existing PCB structure by integrating the ground plane, interposer with through-holes, and signal layers into a unified multi-layer configuration. This merging eliminates the need for separate shield cans, allowing components to be mounted directly on the PCB without requiring additional space for external shielding structures.
Solution Approach 2:
The interposer structure serves multiple functions simultaneously: it provides EMI shielding through its through-holes connected to ground, maintains mechanical support for components, and enables electrical connectivity between layers. This multi-functionality reduces the need for separate dedicated shielding components, thereby maximizing the component mounting area.
3Area of stationary object
If the substrate is miniaturized, then device size is reduced, but EMI protection becomes more difficult to implement
Solution Approach 1:
The solution uses thin film-like structures within the PCB layers to provide EMI shielding. The interposer with its through-holes creates a fine-mesh shielding structure that is analogous to flexible shielding films, allowing effective EMI protection in a extremely thin profile that does not increase substrate size.
Solution Approach 2:
The multi-layer PCB structure combines different material properties: conductive ground planes for EMI shielding, insulating substrate materials for structural support, and through-hole structures for connectivity. This composite approach allows EMI protection to be integrated into the miniaturized substrate without requiring additional space, as the shielding function is distributed throughout the composite structure.
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
This solution effectively addresses EMI issues without the space constraints of shield cans, allowing for the miniaturization of substrates and improved component packing density, thereby enhancing the overall performance and compactness of electronic devices.
Implementation Method 1
The interposer may be disposed on the printed circuit board in a state where one or more through holes of the plurality of through holes are electrically connected with a ground of the printed circuit board. The outer surface of the interposer may include a first conductive region electrically connected with at least one first through hole
Data Source
AI summary
An example electronic device includes a printed circuit board on which one or more circuit components are disposed, and an interposer surrounding at least some circuit components of the one or more circuit components and including an inner surface adjacent to the at least some circuit components and an outer surface facing away from the inner surface and having a plurality of through holes. The interposer is disposed on the printed circuit board such that one or more through holes of the plurality of through holes are electrically connected with a ground of the printed circuit board. The outer surface of the interposer includes a first conductive region electrically connected with at least one first through hole of the one or more through holes, and a non-conductive region, the inner surface of the interposer includes a second conductive region electrically connected with at least one second through hole of the one or more through holes, and the second conductive region includes a region facing the non-conductive region.