Three-dimensional interconnect layers inkjet printed on plastic substrates using continuous-wave xenon light sintering

This paper reports on results demonstrating printed interconnect layers fabricated on the surface of three-dimensional (3D) plastic objects with low heat-resistance using omnidirectional inkjet (OIJ) 3D printing method in conjunction with continuous-wave xenon light sintering. The xenon light sintering was carried out by attaching a condenser lens to the OIJ printing apparatus. The combination of xenon light focused by a condenser lens and a long time exposure helped realize large energy densities of 100 J cm(-2), which are comparable to pulsed xenon light energy. The combination of OIJ and continuous-wave xenon light technologies allowed us to fabricate 3D interconnect layers having resistivities of 13.3 +/- 0.8 Omega along the 3D shape of plastic substrates. Furthermore, we found that the low thermal conductivity of plastic substrates makes it possible to carry out continuous-wave xenon light sintering without requiring assistive heating of the substrate. (C) 2018 The Japan Society of Applied Physics