Shield Film Layout for Modules With Lower Parasitic Capacitance
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Solution Overview
Problem
The occurrence of parasitic capacitance between the shield film provided in a shield-film-equipped electronic component and the shield film on the surface of the sealing resin in a module, which leads to performance degradation.
Innovation Solution
A module design where the surface of the sealing resin on the side distant from the substrate includes a non-shielded region not covered with the shield film, which is superimposed on at least a part of the first conductive film of the electronic component, thereby suppressing the occurrence of parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield film is provided on the outer surface of the sealing resin to prevent noise interference, then the shielding effect is improved, but parasitic capacitance occurs between the shield film on the electronic component and the shield film on the sealing resin
Solution Approach 1:
The shield film on the sealing resin is segmented by creating a non-shielded region that exposes the conductive film of the electronic component. This segmentation allows the shield film to provide noise shielding in other areas while preventing parasitic capacitance formation by leaving a gap where the conductive film is exposed, thus resolving the contradiction between shielding effectiveness and parasitic capacitance prevention.
Solution Approach 2:
Different regions of the sealing resin surface are assigned different functions: some regions have shield film for noise protection, while a specific local region (the non-shielded region) has no shield film to expose the conductive film and prevent parasitic capacitance. This local differentiation allows simultaneous achievement of shielding and capacitance prevention.
2Adaptability or versatility
If the shield film on the electronic component is used as part of wiring for L or C, then the electrical functionality is improved, but the potential difference between this shield film and the shield film on sealing resin causes parasitic capacitance
Solution Approach 1:
The harmful interaction between the conductive film and shield film is extracted by creating a non-shielded region that physically separates them in the vertical direction. This allows the conductive film to maintain its wiring functionality while preventing the formation of parasitic capacitance by eliminating the close proximity that would otherwise cause the unwanted electrical interaction.
Data Source
AI summary
A module includes a substrate including a first surface, a first component mounted on the first surface, at least a part of which is covered with a first conductive film, a sealing resin arranged to cover the first surface and the first component, and a shield film that covers a part of a surface of the sealing resin on a side distant from the substrate. The surface of the sealing resin on the side distant from the substrate includes a shielded region covered with the shield film when viewed in a direction perpendicular to the first surface and a non-shielded region not covered with the shield film. The non-shielded region is superimposed on at least a part of the first conductive film.