Intense Pulsed Light Sintering of Copper Nanoink for Conductive Copper Film

Abstract

Conducting electrodes and films are becoming increasingly important for the printed electronics which can be applied in various fields such as RFID tags, photovoltaics, display and PCB. And copper nanoparticle inks serve as an attractive potential replacement to silver nanoparticle inks because its low cost and good electrical conductivtiy.In this paper, the commercial copper nanoparticle powder with oxide shells were dispersed in the solvent of ethylene glycol. Poly (N-vinylpyrrolidone) (PVP K30) was added to the solvent as capping materials. The prepared copper ink was spin-coated on glass substrate under ambient conduction. Then, the deposited Cu ink was sintered by an intense pulsed light (IPL) system. The sintering effects were investigated with different sintering conditions including pulse energy and pulse duration. The resulting electrical resistivity was 94.1uΩ·cm which is about fifty times as high as that of bulk copper. The high resistivity may be mainly attributed to the porosity of sintered film. Also, crystal phase analysis was performed using x-ray diffraction (XRD) and was found the XRD peaks corresponding to cuprous oxide disappeared after IPL sintering. It was believed that PVP reduced the copper oxide to copper in the process of IPL sintering.