Micro-Roughened Copper Foil for Low-Loss High-Frequency Laminates
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Solution Overview
Problem
Existing technologies struggle to maintain the desired peel strength between copper foil and resin substrate while reducing signal transmission loss in high-frequency applications, leading to potential peel-off issues and reduced defect-free rates in copper clad laminates.
Innovation Solution
A micro-roughened electrodeposited copper foil with a specific surface profile, featuring copper nodule-free and nodule-arranged areas, which enhances peel strength and reduces insertion loss by controlling surface characteristics such as Rlr and Sdr values, ensuring effective high-frequency signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional electrodeposited copper foil with smooth surface is used, then signal transmission loss is reduced, but peel strength between copper foil and resin substrate deteriorates
Solution Approach 1:
The copper foil surface is designed with locally differentiated zones: copper nodule-arranged areas providing mechanical interlocking for strong adhesion, and copper nodule-free areas providing smooth surfaces for low signal loss. This local quality differentiation allows different regions to fulfill different functional requirements simultaneously.
Solution Approach 2:
The surface is segmented into distinct copper nodule-arranged areas and copper nodule-free areas, creating a heterogeneous surface structure. This segmentation enables the copper foil to exhibit both high peel strength (from nodule areas) and low insertion loss (from nodule-free areas).
2Strength
If copper foil surface is made rough to improve peel strength, then adhesion to resin substrate is enhanced, but signal transmission loss increases
Solution Approach 1:
Instead of uniformly roughening the entire surface, the invention applies roughness locally in copper nodule-arranged areas while maintaining smoothness in copper nodule-free areas. This selective local quality approach achieves both strong adhesion and low signal transmission loss.
Solution Approach 2:
The surface is divided into rough segments (copper nodule-arranged areas) for adhesion and smooth segments (copper nodule-free areas) for signal transmission, avoiding the trade-off present in uniform surface treatments.
3Strength
If copper nodule density is increased to enhance peel strength, then adhesion improves, but surface uniformity deteriorates affecting signal transmission
Solution Approach 1:
The surface is segmented into zones with different nodule densities: copper nodule-arranged areas with high nodule density for adhesion, and copper nodule-free areas with zero nodule density for uniformity. This segmentation resolves the contradiction between adhesion enhancement and surface uniformity.
Solution Approach 2:
Different regions of the surface are assigned different nodule densities according to their functional requirements: high density in adhesion-critical areas, zero density in signal transmission-critical areas.
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 micro-roughened copper foil maintains optimal peel strength and significantly reduces insertion loss, promoting high-frequency signal transmission efficiency in copper clad laminates, suitable for applications like 5G networks.
Implementation Method 1
a micro-rough surface, having multiple copper nodule-free areas and multiple copper nodule-arranged areas
Data Source
AI summary
Provided is a micro-roughened electrodeposited copper foil, which comprises a micro-rough surface and multiple copper nodules. The micro-roughened electrodeposited copper foil has an Sdr of 0.01 to 0.08. With the surface characteristics, the electron path distance can be shortened, such that the micro-roughened electrodeposited copper foil can reduce the insertion loss of the copper clad laminate at high frequencies and have the desired peel strength.