The COT (Color Filter on TFT Array) Structure without the use of organic insulator in TFT substrate and photolithography process in upper substrate was developed. Cost reduction and enhancement of light efficiency could be achieved by adopting inorganic insulator, SiNx, instead of thick organic layer. Through photolithography-free structure in upper substrate where bare glass is used as upper unit in cell process, we could simplify manufacturing steps and realize margin free COT in cell assembly. To embody this COT configuration, firstly the outer region of display area was re-designed to prevent light leakage that occurs in the borderline between panel and mechanical parts. Secondly, low temperature CVD (Chemical Vapor Deposition) process that can guarantee adhesion stability between SiNx and CF (Color Filter) layer was also developed. And finally, novel cell assembly method for using bare glass as the upper substrate was adopted.