Excimer laser is used for back channel etched (BCE) a-Si TFT fabrication for the first time. KrF laser could easily and successfully lift-off ITO on photo-resist comparing to traditional chemical lift-off process. Besides, this maskless laser lift-off technology could save much process time from mask alignment step. The mechanism of laser assisted ITO lift-off (LAIL) technology was carefully studied in this paper. With suitable laser fluence energy, ITO could be precisely patterned as designed. Very wide range of laser fluence energy was obtained in our LAIL technology. TFT device fabricated by LAIL technology exhibits the same electrical characteristics performance as traditional non-lift-off one.

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.