One-pot synthesis of surface oxidation-suppressed multidimensional copper particles for photonically sintered, directly printed conductive features

Abstract

Recently, an exploit of highly conductive printed features has been recognized as one of main technologies for facilitating multi-functional integrated microelectronics systems. Among various metallic substances, printable Cu materials with excellent cost-effectiveness and electrical properties have gained tremendous attention in a conjunction with the usage of the instantaneous photonic sintering process. In this study, we have suggested a facile methodology of synthesizing multidimensional Cu particles, a mixture of nano-sized spherical particles and micro-sized flakes, from a single one-batch chemical/mechanical reaction. The chemical factors involved in obtaining the sub-micron Cu particles, with multimodal size distribution, are elucidated with an investigation of the role of surface capping molecules. A subsequent mechanical milling procedure enables one-pot synthesis of multidimensional Cu particles through morphological transformation from multimodal sub-micron Cu particles. It is demonstrated that, by an instant flash sintering process for 1–2 msec, the multidimensional printed Cu features exhibit superior electrical properties with values of resistance of 2.0 and 2.8 Ω/cm on polyimide and polyethylene naphthalate substrates, respectively.