RF Module Shield Wall Groove Depth for High-Density Mounting
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Solution Overview
Problem
Existing radio-frequency modules face challenges in high-density component mounting due to noise interference between components, which is exacerbated by the formation of shield walls that can damage the circuit board during laser machining and limit the mounting area.
Innovation Solution
A radio-frequency module design featuring a sealing resin layer with a shield wall groove that does not reach the circuit board's surface, utilizing a third component with an electrode on its side surface to maintain shielding characteristics and prevent warpage, while allowing for high-density component mounting by reducing laser beam influence and ensuring effective filling of electrically conductive paste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a groove is formed in the sealing resin layer by laser beam machining to create a shield wall, then shielding effectiveness between components is improved, but the circuit board or internal circuits may be damaged
Solution Approach 1:
The groove depth is varied locally: in regions where components are mounted, the groove does not reach the circuit board surface, while in regions without components, the groove extends deeper to provide effective shielding. This local differentiation maintains shielding effectiveness where needed while preventing circuit board damage where components are present.
Solution Approach 2:
The groove is segmented into multiple depth regions corresponding to different component locations. The groove depth is controlled to stop before reaching the circuit board in component areas, creating a stepped or varied depth profile that provides shielding only in non-component regions while protecting components from laser damage.
2Reliability
If the groove is formed to reach the circuit board surface for effective shielding, then shielding characteristics are improved, but the mounting area is limited
Solution Approach 1:
The groove depth is locally optimized: shallower in component mounting regions to preserve mounting area, and deeper in non-component regions to maintain shielding characteristics. This creates a differentiated groove profile that adapts to local requirements.
3Reliability
If the groove completely separates the sealing resin layer for effective shielding, then shielding effectiveness is improved, but warpage or deformation occurs
Solution Approach 1:
Instead of completely separating the sealing resin layer with the groove, the groove is formed to a controlled depth that provides sufficient shielding effectiveness while leaving the sealing resin layer partially connected. This partial separation maintains structural integrity and prevents warpage while achieving the necessary shielding performance.
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 configuration enables high-density component mounting without restricting the circuit board's area, maintains shielding effectiveness, and minimizes warpage or deformation, while simplifying the laser machining process and ensuring reliable filling of the shield wall with conductive paste.
Implementation Method 1
A groove is formed in a sealing resin layer by laser beam machining
Implementation Method 2
a conductor, such as electrically conductive paste, is filled into the groove
Implementation Method 3
a shield wall that shields against not only the noise from the outside but also the noise between mounted components from each other
Data Source
AI summary
A radio-frequency module includes a multilayer circuit board, a plurality of components mounted on a top surface of the multilayer circuit board, a sealing resin layer laminated on the top surface of the multilayer circuit board and sealing a plurality of components, and a shield wall disposed in a groove formed in the sealing resin layer between the component and the component. The shield wall has a region that overlaps the component when viewed in a direction perpendicular to the top surface of the multilayer circuit board. The groove in the overlapped region is formed with a depth that does not reach the component. In the component, a terminal electrode that covers the entire surfaces of side surfaces, and part of a top surface, a bottom surface, and side surfaces is formed.