Closed-Cavity PCB Lamination for RF Shielding
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Solution Overview
Problem
There is a need for an improved printed circuit board (PCB) structure that includes an enclosed cavity, such as an air cavity, and a method for manufacturing it, particularly for radio-frequency (RF) electronics.
Innovation Solution
A closed cavity printed circuit board is provided, comprising a substrate layer, a first metal layer, a core layer that defines a closed cavity, and a second metal layer. The method involves forming a cavity in a core structure, laminating it with adhesive and metal layers to create a laminate structure, and patterning the metal layers to define the closed cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an open cavity structure is used in the PCB, then manufacturing is simpler, but shielding effectiveness is insufficient for RF components
Solution Approach 1:
The patent merges the cavity enclosure with the PCB lamination structure itself. The core layer forms the cavity while being integrated into the multi-layer PCB stackup, eliminating the need for separate enclosure components. This combining approach achieves effective shielding while maintaining manufacturing simplicity.
Solution Approach 2:
The core layer serves multiple functions simultaneously: it provides structural support for the PCB, defines the enclosed cavity shape, and acts as the shielding barrier for RF components. This multi-functionality reduces overall device complexity while achieving the shielding objective.
2Reliability
If a closed cavity is formed by removing metal layers and re-laminating, then shielding is improved, but manufacturing complexity increases
Solution Approach 1:
The cavity structure is prepared in advance during the PCB lamination manufacturing process. The core layer is pre-formed with the cavity geometry before final assembly, allowing subsequent metal layers to be deposited around it. This preliminary preparation simplifies the overall manufacturing flow despite the complex cavity formation.
Solution Approach 2:
The core layer acts as an intermediary structure that facilitates cavity formation. By using the core layer as the cavity-defining element rather than trying to form cavities in finished metal layers, the manufacturing process becomes more manageable while still achieving the desired shielding effect.
3Reliability
If multiple lamination steps are used to create the closed cavity, then cavity enclosure is achieved, but production time increases
Solution Approach 1:
The patent combines multiple manufacturing operations into integrated lamination steps. The formation of the closed cavity, deposition of metal layers, and structural assembly are merged into a coordinated multi-layer lamination process, reducing the total number of separate production cycles required.
Data Source
AI summary
A method of making a printed circuit board structure including a closed cavity is provided. The method can include the steps of forming a cavity in a core structure of a core layer, laminating each of a top surface and a bottom surface of the core structure with an adhesive layer and a metal layer to prepare a laminate structure and cover the cavity to define a closed cavity. The method also includes forming vias through the laminate structure, and patterning the metal layers in the laminate structure.