A modified offset roll printing for thin film transistor applications

In order to realize a high resolution and high throughput printing method for thin film transistor application, a modified offset roll printing was studied. This roll printing chiefly consists of a blanket with low surface energy and a printing plate (cliche) with high surface energy. In this study, a finite element analysis was done to predict the blanket deformation and to find the optimal angle of cliche's sidewall. Various etching methods were investigated to obtain a high resolution cliche and the surface energy of the blanket and clich was analyzed for ink transfer. A high resolution cliche with the sidewall angle of 900 and the intaglio depth of 13 mu m was fabricated by the deep reactive ion etching method. Based on the surface energy analysis, we extracted the most favorable condition to transfer inks from a blanket to a clich, and thus thin films were deposited on a Si-cliche to increase the surface energy. Through controlling roll speed and pressure, two inks, etch-resist and silver paste, were printed on a rigid substrate, and the fine patterns of 10 mu m width and 6 mu m line spacing were achieved. By using this printing process, the top gate amorphous indium-gallium-zinc-oxide TFTs with channel width/length of 12/6 mu m were successfully fabricated by printing etch-resists. (C) 2011 Elsevier B.V. All rights reserved.