PCB Dielectric Layer and Plating Height for Signal Loss Reduction
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Solution Overview
Problem
The existing process for embedding a copper coin in printed circuit boards (PCBs) for heat dissipation results in inefficient signal transfer due to the formation of a stub during the grounding process, which causes signal losses as components need to jump over this stub to reach the ground layer.
Innovation Solution
Incorporating a thin dielectric layer between the conductive and non-conductive layers, allowing direct electrolytic copper plating to connect the copper coin to the ground layer without the need for electroless copper plating, thereby reducing the stub height and variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroless copper plating is used to connect the coin to the ground layer, then the coin is properly grounded, but a stub is formed that causes signal losses
Solution Approach 1:
The invention extracts and removes the harmful stub portion from the plating structure. By controlling the plating process to extend less than 50 um above the second conductive layer, the harmful stub that causes signal loss is eliminated while maintaining the essential ground connection function between the coin and ground layer.
Solution Approach 2:
The invention changes the critical parameter of plating height from the conventional approach (extending well above the conductive layer) to a controlled extension of less than 50 um. This parameter change eliminates the stub formation while maintaining adequate electrical connection, thereby resolving the contradiction between reliable grounding and signal loss prevention.
2Reliability
If the plating extends higher above the second conductive layer, then the ground connection is more robust, but the stub length increases causing greater signal loss
Solution Approach 1:
The invention optimizes the plating height parameter to extend less than 50 um above the second conductive layer. This precise parameter control achieves the optimal balance point where adequate ground connection robustness is maintained while the stub length is minimized to prevent signal loss.
3Loss of energy
If a dielectric layer is added between the conductive layer and non-conductive layer, then signal loss is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The dielectric layer serves multiple functions simultaneously: it provides electrical insulation between conductive layers, reduces signal loss by minimizing stub interaction, and maintains structural integrity of the PCB. By consolidating these multiple functions into a single layer, the invention reduces overall complexity despite the added functionality.
4Temperature
If the coin is embedded deeper in the PCB, then heat dissipation is improved, but the stub length increases causing signal loss
Solution Approach 1:
The invention changes the plating height parameter to extend less than 50 um above the second conductive layer, which decouples the relationship between coin embedding depth and stub length. This allows the coin to be positioned optimally for heat dissipation while the controlled plating extension prevents excessive stub formation, thereby resolving the contradiction between heat dissipation and signal loss.
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 approach reduces signal loss by minimizing the stub length to less than 50 um, improving the ground connection performance and maintaining uniform cavity dimensions, thus enhancing the PCB's signal transfer efficiency.
Implementation Method 1
A copper coin has a high thermal conductivity and heat, generated from components on the PCB, is transferred to the copper coin quickly and dispersed into the air
Implementation Method 2
The printed circuit board also includes a plating within the cavity to connect the coin with the second conductive layer
Data Source
AI summary
A printed circuit board includes a first, second, and third conductive layer. The printed circuit boards also includes a first non-conductive layer between the first and second conductive layers and a second non-conductive layer between the second and third conductive layers. The printed circuit board further includes a dielectric layer between the second conductive layer and the second non-conductive layer and a coin for heat dispersion located underneath the dielectric layer. The printed circuit board also includes a cavity for receiving a component and a plating within the cavity to connect the coin with the second conductive layer. The plating extends less than 50 um above the second conductive layer.