Instant Inkjet Circuits by silver nano-particle ink realized home-brew electric circuit fabrication. However, current method can support only single-layered patterns, and conventional inter-layer connection methods are not suitable.
We evaluated various easy-to-use inter-layer connection methods by making via holes, especially the ones made by different drilling mechanisms. We showed that the felting needle is the best candidate as it can establish good conductivity immediately after the nano-particle ink is printed into the hole, without using any curing process.
Tung Duc Ta, Masaaki Fukumoto, Koya Narumi, Shigeki Shino, Yoshihiro Kawahara, and Tohru Asami, “Interconnection and Double Layer for Flexible Electronic Circuit with Instant Inkjet Circuits,” Proceedings of the 2014 ACM International Joint Conference on Pervasive and Ubiquitous Computing (UbiComp2015), pp.181-190, Osaka, Japan, Sept. 2015.