24.1: 3-Masks TFT Process by Using ITO Lift-Off Technique

Reducing TFT manufacturing steps in recent years has become an unavoidable technology trend for many TFT- LCD makers in order of cost reduction purpose. Here, we proposed a new mask reduction process (3-masks TFT) by chemical lift-off which based on conventional 4-masks TFT fabrication process. The major spirit of 3-masks technique combines passivation layer and pixel electrode formed in one photolithography process with HTM (Half tone mask). with this new HTM design, a small SiNx island cross TFT source contact edge border could be created to provide a pixel electrode conducting path away from electrical signal opening. In order to enhance to lift-off ability, new optional extra lift-off enhancement designs could be adopted to improve chemical lift-off efficiency. Through the development of process and design of TFTs using 3-masks HTM lift-off scheme, one first 1.8″ HTM lift-off panel was demonstrated which exhibits same performance of conventional fabricated one.