Multi-Layer Circuit Board for Low-Loss High-Frequency Adhesion
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Solution Overview
Problem
Existing circuit boards experience high signal transmission loss and poor adhesion between the circuit layer and insulating layer, particularly at high frequencies, due to surface roughness and conductor losses, which hinder their application in high-frequency applications.
Innovation Solution
A circuit board design featuring a circuit layer with multiple metal layers, including a third metal layer that fills valleys on the surface and side surfaces of the first and second metal layers, reducing surface roughness and enhancing adhesion through the use of copper and tin materials, which improves adhesive force with insulating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the surface roughness of the circuit layer is reduced, then signal transmission loss is minimized, but adhesion between the circuit layer and the insulating layer decreases
Solution Approach 1:
The patent applies different surface roughness characteristics to different regions of the circuit layer. The first circuit layer maintains higher surface roughness for adhesion, while the second circuit layer provides smoother surfaces for signal transmission, creating local quality differentiation that resolves the contradiction between adhesion and signal loss
Solution Approach 2:
The patent uses a composite structure with multiple circuit layers having different surface characteristics. The combination of a rough first circuit layer and a smoother second circuit layer creates a composite system that simultaneously achieves both good adhesion and low signal transmission loss
2Loss of energy
If the surface roughness of the circuit layer is reduced, then signal transmission loss is minimized, but manufacturing complexity increases due to additional metal layers
Solution Approach 1:
The patent segments the circuit layer into multiple distinct layers (first circuit layer and second circuit layer), each with specific functions. The first layer provides adhesion with the insulating layer, while the second layer optimizes signal transmission, dividing the complex requirements into manageable segments
3Loss of energy
If conductor losses are minimized through metal thin layers, then signal transmission is improved, but surface roughness increases causing skin effect losses
Solution Approach 1:
The patent creates different surface quality characteristics in different layers. The first circuit layer has higher surface roughness that is acceptable for adhesion purposes, while the second circuit layer provides the smooth surface needed to minimize skin effect losses in the conductive paths
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
The design reduces signal transmission loss and enhances adhesion, making the circuit board suitable for high-frequency applications while improving electrical and physical reliability.
Implementation Method 1
a third metal layer disposed on the first metal layer and the second metal layer... the third metal layer fills at least a portion of the plurality of valleys
Implementation Method 2
signal transmission loss may be reduced... a profile of the surface of the first layer is different from a profile of a surface of the second layer
Implementation Method 3
there is a problem that an adhesion between the circuit layer and the insulating layer decreases accordingly
Data Source
AI summary
A circuit board according to an embodiment includes a first insulating layer; and a circuit layer disposed on the first insulating layer, wherein the circuit layer includes: a first layer disposed on the first insulating layer, and a second layer partially disposed on a surface of the first layer, wherein a profile of the surface of the first layer is different from a profile of a surface of the second layer.