A new patterning process concept for large-area transistor circuit fabrication without using an optical mask aligner

A new concept to produce large thin film transistor liquid crystal displays (TFT-LCD´s) without using an optical mask aligner is proposed which emphasizes patterning technology. Some experimental thin film transistors (TFT´s) are fabricated according to the concept and operated like conventional transistors fabricated by using an optical mask aligner. The concept includes improvement of printing technology and development of a double-layer resist method. The latter method employs a printed ink pattern and a photoresist. This prevents contamination of thin films by metal impurities which affect electrical characteristics of the TFT´s. A special gravure offset printing technology is proposed, composed of a large thixotropy valued UV ink, and a fine, precision etched glass intaglio. The experimental TFT´s, with a designed minimum gate length of 10 μm, have comparable electric characteristics to those of conventional poly-Si TFT´s