Electrodeposited Copper Foil Matte Side Roughness Control
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Solution Overview
Problem
Electrodeposited copper foils with high surface roughness exceed the requirements for high-frequency applications, such as 5G communication, due to increased signal loss caused by the 'skin effect', and existing methods struggle to achieve low enough surface roughness without compromising mechanical properties or introducing defects.
Innovation Solution
A method using an electrolyte with copper ions, halogen ions, 3-mercapto-1-propane sulfonate, a nitrogen-containing polymer leveler, and a polyether suppressor at specific concentrations to produce copper foils with a matte side surface roughness of 0.8 μm or less, ensuring low signal loss and maintaining mechanical properties through controlled deposition and suppression of defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional electrolytes with only copper ions and sulfate ions are used, then the production process is simple, but pinholes and micro porosities are produced resulting in serious defects
Solution Approach 1:
The patent modifies the electrolyte composition by adding specific additives (brightener, leveler, suppressor) to change the deposition parameters and surface properties of the copper foil, thereby preventing defects while maintaining production simplicity
Solution Approach 2:
The electrolyte is formulated as a composite system containing copper sulfate, sulfuric acid, and multiple organic additives working together to achieve both defect-free deposition and manufacturing efficiency
2Manufacturing precision
If large quantities of brightener such as glue and/or thiourea are added to lower the profile of the matte side, then surface roughness is reduced, but the room-temperature elongation rate and high-temperature elongation rate are abruptly lowered resulting in degradation of mechanical properties
Solution Approach 1:
The patent uses a specific combination of additives at controlled concentrations to achieve low surface roughness (Rz ≤ 0.80 μm) while maintaining mechanical properties through optimized deposition parameters
Solution Approach 2:
The patent introduces a leveler additive as an intermediary substance that mediates between the brightener and suppressor to control surface morphology without compromising mechanical integrity
3Ease of manufacture
If a higher surface roughness copper foil is used, then the manufacturing process is simpler, but the signal loss increases in high speed/high frequency applications due to the skin effect
Solution Approach 1:
The patent optimizes electrolyte composition and deposition parameters to achieve ultra-low surface roughness (Rz ≤ 0.80 μm) that minimizes signal loss in high-frequency applications while maintaining manufacturing efficiency
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 method achieves electrodeposited copper foils with reduced surface roughness and improved mechanical properties, enabling effective transmission lines for frequencies above 77 GHz with reduced signal loss and long-term electrolyte stability, while avoiding defects and maintaining mechanical integrity.
Implementation Method 1
The process and production of electrodeposited copper foil for use in printed circuit boards is basically a plating technique, as it involves arranging two electrodes (a cathode and an anode) in an electrolyte containing a copper salt, passing current between the electrodes and depositing copper on the cathode with a desired thickness
Implementation Method 2
a polyether suppressor at a concentration comprised between 15 and 30 ppm... a nitrogen-containing polymer leveler at a concentration comprised between 5 and 12 ppm... to produce copper foils with a matte side surface roughness of 0.8 μm or less
Data Source
AI summary
A method for producing an electrodeposited copper foil with a matte side having a Rz ISO of 0.8 μm or less, the electrodeposited copper foil being continuously formed in an electroforming cell including a rotating drum-shaped cathode, a stationary anode and an electrolyte. The electrolyte comprises: copper, preferably in the form of copper ions, at a concentration of at least 60 g/L; a halogen ion at a concentration composed of between 30 and 50 ppm; 3-mercapto-1-propane sulfonate at a concentration composed of between 5 and 15 ppm; a nitrogen-containing polymer leveler at a concentration composed of between 5 and 12 ppm, the nitrogen-containing polymer leveler having an average molecular weight Mw composed of between 1 000 and 30 000 g/mol; and a polyether suppressor at a concentration composed of between 15 and 30 ppm, the polyether suppressor having an average molecular weight Mw composed of between 500 and 12 000 g/mol.