High-resolution, high-aspect ratio conductive wires embedded in plastic substrates

Area of Science:

• Materials Science
• Nanotechnology
• Electrical Engineering

Background:

• Flexible electronics demand high-resolution, conductive interconnects.
• Existing fabrication methods often struggle with resolution, aspect ratio, or mechanical flexibility.

Purpose of the Study:

• To develop a novel fabrication method for high-resolution, high-aspect ratio metal wires embedded in plastic substrates.
• To enable applications in advanced flexible electronics.

Main Methods:

• Sequential fabrication involving imprint lithography to create microchannels and reservoirs in a polymer substrate.
• Inkjet printing of a reactive silver (Ag) ink into reservoirs, followed by capillary wicking into channels.
• Electroless copper (Cu) plating using the Ag ink as a seed layer for wire formation.

Main Results:

• Fabrication of highly conductive metal wires (>50% bulk metal conductivity) with a minimum line width of 2 μm and spacing of 4 μm.
• Achieved a high aspect ratio of 0.6 for the embedded wires.
• Demonstrated good mechanical flexibility and minimal electrical performance degradation after extensive bending cycles.

Conclusions:

• The presented method successfully fabricates high-resolution, high-aspect ratio, and flexible embedded metal wires.
• This technique offers a promising route for manufacturing robust interconnects for next-generation flexible electronic devices.