Highly efficient electroplating of (220)-oriented nano-twinned copper in methanesulfonic copper baths

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• High-density nanotwinned structures in copper are crucial for improving material properties.
• Conventional methods use organic additives, leading to impurities and aging issues.

Purpose of the Study:

• To introduce a high-rate fabrication method for (220)-orientation nanotwinned copper foils.
• To understand the role of chloride ions in nanotwin formation.
• To provide a controllable manufacturing avenue for nanotwinned copper.

Main Methods:

• Fabrication of copper deposits in a concentrated methanesulfonate copper solution with minimal chloride ions.
• Utilizing direct current (DC) plating at 60 A dm^-2 (ASD) and ambient temperature.
• Investigating the influence of chloride ion coverage on the cathode surface.

Main Results:

• Achieved high-rate plating capability (60 ASD) at ambient temperature.
• Successfully formed numerous twin boundaries with controllable average spacing of 30 nm.
• Identified chloride ion coverage as a key factor in nanotwin formation via a coordinated ion-complex mechanism.
• Demonstrated stress relaxation within copper deposits due to nanotwinned structure formation.

Conclusions:

• The chloride bridge mechanism boosts Cu+ intermediates, promoting nanotwin formation.
• Nanotwinned structures reduce internal residual stress in copper deposits.
• This method offers a practical and controllable approach for manufacturing (220)-oriented nanotwinned copper.