title: In situ monitoring of flash-light sintering of copper nanoparticle ink for printed electronics.
abstract: In this work, a flash-light sintering process for Cu nanoinks was studied. In order to precisely monitor the milliseconds flash-light sintering process, a real-time Wheatstone bridge electrical circuit and a high-rate data acquisition system were used. The effects of several flash-light irradiation conditions (irradiation energy, pulse number, on-time, and off-time) and the effects of the amount of poly(N-vinylpyrrolidone) in the Cu nanoink on the flash-light sintering process were investigated. The microstructures of the sintered Cu films were analyzed by scanning electron microscopy. To investigate the oxidation or reduction of the oxide-covered copper nanoparticles, a crystal phase analysis using x-ray diffraction was performed. In addition, the sheet resistance of Cu film was measured using a four-point probe method. From this study, it was found that the flash-light sintered Cu nanoink films have a conductivity of 72 Ωm/sq without any damage to the polyimide substrate. Similar nanoinks are expected to be widely used in printed and flexible electronics products in the near future.
authors.affiliation: Department of Mechanical Engineering, Hanyang University, Seoul, Korea.
authors.forename: Hyun-Jun
authors.initials: HJ
authors.lastname: Hwang
authors.forename: Wan-Ho
authors.initials: WH
authors.lastname: Chung
authors.forename: Hak-Sung
authors.initials: HS
authors.lastname: Kim