Lab talk
Sep 7, 2012
Metallic nanowire surface fasteners provide alternative to soldering
Researchers from Nagoya University, Japan, have proposed a patterned structure of push-together gold nanowire arrays dubbed “surface fasteners” that enable cold bonding of surface mount technology (SMT). The technique represents a low-temperature alternative to reflow soldering, which could avoid thermal damage of components and help make circuits much easier to disassemble and recycle at the end of their lifetime.
To test the concept, two circuit boards featuring a pattern of gold nanowire arrays (synthesized by porous alumina template-assisted electrodeposition) were connected to each other under different preloads. The parasitic resistance across the connection was measured using a four-point probe method after the preload was completely removed. Also, normal and shear bonding strengths were evaluated.
The team demonstrated that the mechanical bonding enables normal and shear bonding strengths of more than 5 N/cm2. Also, the researchers found that the parasitic resistance of a pair of surface fasteners is only approximately 2 Ω.
Surface fasteners based on high melting point metallic nanowires are temperature resistant for many critical applications. In addition, bonding without solder material is a positive step for the recycling of rare metals in SMDs.
Further details can be found in the journal Nanotechnology.
About the author
The study was conducted by Prof. Yang Ju’s research group from the Department of Mechanical Engineering at Nagoya University. Prof. Ju’s laboratory is carrying out innovative research into material strength and material characterization using a combination of nano-characterization and nanomechanics. The team also focuses on the development of micro/nano-functional and intelligent materials as well as the characterization approaches.
