Flashlight Sintering Characteristics of the Inkjet-Printed Nanosized Copper Ink on an Auxiliary Heated Paper Substrate

Abstract

The flashlight sintering characteristics of inkjet-printed nanosized copper ink on paper substrates with varying pattern widths and intervals were studied. The copper nano particles (CNPs) synthesized using vapor self-assembled multilayer (VSAM) method to prevent oxidation, were produced with ink and patterned on a paper substrate through inkjet printing. The width and interval of the Cu patterns were varied from 350 to 550 mu m to investigate the flashlight sintering tendency. It was confirmed that the Cu pattern resistivity decreased as the width of the Cu pattern increased, with decreasing interval between the Cu patterns. For the Cu pattern with the largest width and narrowest interval, the lowest specific resistivity was 6.43 x 10-6 ohm center dot m. For auxiliary heating at 80 degrees C, the lowest resistivity of the Cu pattern was 7.10 x 10-6 ohm center dot m with improved adhesion to the substrate, and this resistivity was 6.2 times lower than that without auxiliary heating. The temperature gradient of the CNP pattern during the flashlight sintering process was predicted using custom made simulation program. Therefore, the experiments and simulations confirmed that the wider the width and the narrower the interval between patterns, the flashlight sintering characteristics improved through higher heat generation by minimizing heat spreading.