Two-Step Flash-Light Sintering of Copper-Based Inkjet-Printed Patterns onto Polymer Substrates Used in Flexible Electronic Devices

摘要

High-speed flash-light sintering to fabricate inkjet patterns on the flexible substrates employed in lightweight devices is used. A two-step sintering process, i.e., presintering to cause slight necking of copper nanoparticles (CNPs) and final sintering to complete densification, is used to sinter copperbased inkjet patterns. These patterns are more dense and less resistive than those formed via one-step sintering. The specific resistivity of the pattern created using only the second sintering step is 2.65 × 10~(-7) Ωm and that of the two-step pattern is 0.84 × 10~(-7) Ω m, and the value shows little change over 180 days. Two-step-sintered patterns on a polyimide substrate exhibit very dense microstructures, surface porosity <7%, and no damage. Thus, highly conductive copper-based inkjet patterns on a flexible substrate are successfully fabricated.