PCB Circuit Pattern Surface Roughness Control for Signal Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Printed circuit boards experience significant signal loss due to the skin effect, particularly at higher frequencies, as a result of surface roughness in the circuit pattern, which acts as resistance and increases transmission loss.
Innovation Solution
A printed circuit board with a circuit pattern that maintains surface roughness between 0.1 μm to 0.31 μm on its upper, lower, first side, and second side surfaces, with varying roughness depending on surface lengths, and an impedance of 35.3Ω or less, to minimize signal loss by controlling surface roughness and optimizing signal transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional surface processing methods (OSP, electrolytic nickel/gold, electroless nickel/palladium/gold) are used on circuit patterns, then soldering and wire bonding properties are improved, but surface roughness increases causing signal loss at high frequencies
Solution Approach 1:
The invention changes the surface roughness parameter of the circuit pattern to a specific range (Ra 0.05μm to 0.50μm) to reduce signal loss while maintaining adequate soldering and wire bonding properties. This parameter optimization resolves the contradiction by finding a roughness value that balances both requirements.
Solution Approach 2:
The invention applies different surface treatments to different regions: the circuit pattern surface is treated to have controlled roughness for signal transmission, while other surfaces maintain traditional processing for soldering and bonding. This local differentiation allows each region to optimize for its specific function.
2Loss of energy
If surface roughness is reduced to minimize signal loss, then conductor loss due to skin effect is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The invention specifies a surface roughness range (Ra 0.05μm to 0.50μm) that balances signal loss reduction with manufacturing feasibility. This parameter optimization resolves the contradiction by defining acceptable roughness limits that achieve low conductor loss without requiring excessive manufacturing precision.
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 controlled surface roughness reduces signal loss during high-frequency transmission by minimizing resistance, thereby enhancing the signal transmission characteristics and maintaining efficient signal movement across the circuit pattern.
Implementation Method 1
The conductor loss can be further increased by the skin effect of the copper foil that appears more prominently at higher frequencies
Data Source
AI summary
A printed circuit board according to an embodiment includes: an insulating layer; and a circuit pattern disposed on the insulating layer, wherein the circuit pattern includes an upper surface, a lower surface, a first side surface, and a second side surface, and surface roughness Ra of at least three surfaces of the upper surface, the lower surface, the first side surface, and the second side surface of the circuit pattern is 0.1 μm to 0.31 μm.