Self-Supporting Porous Silver Microspheres with Large Deformability for Low-Resistance Interconnection in Flexible...

Area of Science:

• Materials Science
• Nanotechnology
• Electrical Engineering

Background:

• Conductive microparticles are crucial for interconnecting flexible and high-density electronic devices.
• Conventional metal-coated polymer microspheres have limited deformability (∼60%), causing shell fracture and high contact resistance.
• This limits their application in advanced electronic systems requiring stable, low-resistance interfaces.

Purpose of the Study:

• To develop novel conductive microparticles with enhanced deformability and lower contact resistance.
• To investigate the deformation behavior and electrical properties of these new microparticles.
• To demonstrate their effectiveness in reliable electronic interconnections.

Main Methods:

• Synthesis of self-supporting porous silver microspheres (PAg-MS) using liquid-solid interfacial nonwetting spheroidization and dealloying.
• Nanoindentation experiments to quantify mechanical properties and deformation.
• Theoretical calculations to analyze densification and contact resistance.
• Fabrication and testing of LED array interconnections on rigid and flexible substrates.

Main Results:

• PAg-MS exhibit high porosity (≈ 51%) and enhanced deformability exceeding 80% during compression.
• Gradual densification of PAg-MS increases electrode contact area and shortens conductive paths.
• Achieved significantly reduced contact resistance of 0.023 Ω mm².
• Demonstrated reliable LED array interconnections on diverse substrates.

Conclusions:

• PAg-MS offer superior mechanical and electrical properties compared to conventional microspheres.
• Their enhanced deformability and low contact resistance are ideal for flexible and high-density electronic interconnections.
• PAg-MS represent a versatile solution for various electronic systems, enhancing device reliability and performance.