High-Frequency Module Shielding Groove Design
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Solution Overview
Problem
In high-frequency modules with a sealing resin layer and a shield layer, the existing configuration faces challenges in filling a groove for shielding across a step formed due to varying component thicknesses, leading to uneven filling of conductive paste and potential regions not filled with paste.
Innovation Solution
The design includes a groove in the sealing resin layer with a cross-sectional shape that has a larger area at the higher portion side of the step, allowing for increased filling capacity and ease of filling with conductive paste, while maintaining a constant width connection to the wiring board, thus addressing the issue of uneven paste distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the sealing resin layer is changed to match component thicknesses, then the excessive portion of the sealing resin layer is decreased and the module size is reduced, but a step is formed at the surface making it difficult to fill the trench evenly with conductive paste
Solution Approach 1:
The groove cross-sectional area is varied locally along its length to match the step height of the sealing resin layer. The groove has a larger cross-sectional area at the higher portion side and a smaller cross-sectional area at the lower portion side, allowing uniform conductive paste filling across the step while maintaining the reduced module size.
2Object-affected harmful factors
If a trench is formed to extend across the step in the sealing resin layer, then shielding between components is achieved, but it becomes difficult to fill the trench evenly with conductive paste at both higher and lower portions
Solution Approach 1:
The groove cross-sectional area is locally adjusted along its length to compensate for the step in the sealing resin layer. By making the groove area larger at the higher portion and smaller at the lower portion, the conductive paste can be filled uniformly across the entire trench, ensuring effective shielding while maintaining manufacturing precision.
3Object-affected harmful factors
If the trench extends across the step, then shielding function is provided, but regions not filled with paste may remain leading to incomplete shielding
Solution Approach 1:
The groove cross-sectional area is locally optimized along its length to ensure complete paste filling. The larger area at the higher portion and smaller area at the lower portion work together to eliminate air pockets and ensure the conductive paste completely fills the groove, guaranteeing reliable electromagnetic shielding.
Data Source
AI summary
A high-frequency module includes a wiring board; a plurality of components mounted on an upper surface of the wiring board; a sealing resin layer that is stacked on the upper surface of the wiring board and that has a step; a groove that is formed in the sealing resin layer to intersect with the step when the wiring board is viewed in plan view, and that extends between predetermined components; and a shield wall disposed in the groove and formed with a conductor. The groove includes a first portion at an upper surface side of the wiring board and a second portion at an upper surface side of the sealing resin layer, the second portion being continuous from the first portion. An area of the second portion is larger than an area of the second portion.