Cu 인쇄패턴의 Ni electroplating 을 통한 유연 솔더러블 인쇄전극형성

Abstract

: Printed electronics technology is receiving a lot of interests because it has simple process steps, fast process times and can be applied to flexible substrates. On the other hand, there are some issues about applicability and solderability for real electrical circuits. Because the printed copper (Cu) electrode has a lot of voids inside the electrode pattern and rough surface on it, the adhesive force between solder material and Cu electrode is not good. In this study, Cu precursor/nanoparticle (CPN) ink was printed on a polymer substrate and sintered by intense pulsed light (IPL) irradiation. Cu precursor was thermally decomposed by IPL to form Cu seeds between Cu NPs and filled voids of the electrode. In addition, the Cu electrode was electroplated with nickel (Ni) to reduce surface roughness, improve solderability and oxidation resistance. Electroplating simulations were conducted to observe the relationship between Ni electroplating conditions and surface roughness. Surface morphology of each electrode was observed through scanning electron microscopy (SEM) and a 3D optical profiler. Shear tensile tests were performed using a micro tensile tester to observe the shear strength between solder and electrodes. By improving the surface morphology of the electrode through mixing Cu precursor into the Cu ink and Ni-electroplating, a printed electrode with high electrical conductivity, high reliability and high solderability was achieved.