Trade-Off Between Surface Roughness and Crystallographic Orientation in Copper Electrodeposition via...

Area of Science:

• Materials Science
• Electrochemistry
• Surface Science

Background:

• High-frequency 5G/6G communications require copper foils with specific properties.
• Sub-micron surface roughness (Rz < 0.6 μm) is crucial to minimize the skin effect.
• (111)-preferred orientation is needed for electromigration resistance.

Purpose of the Study:

• To investigate the synergistic mechanism of additive formulations in copper electrodeposition.
• To understand how additives influence surface roughness and crystallographic orientation.
• To quantify the trade-off between surface planarization and texture.

Main Methods:

• Electrochemical analysis
• Microstructural analysis
• Systematic variation of additive formulations (MPS, PEG, Cl-, GEL)

Main Results:

• A ternary additive system (MPS + PEG + Cl-) caused severe surface roughening.
• High-concentration gelatin introduced a
• High-N/Low-D
• regime, reducing roughness from ~449.5 nm to ~81.3 nm.
• This regime suppressed growth via steric hindrance but randomized crystal texture.

Conclusions:

• Additive formulation critically impacts copper foil properties for high-frequency applications.
• A kinetic trade-off exists between achieving extreme surface planarization and controlling crystallographic orientation.
• Findings provide a framework for designing advanced interconnect materials.