New approaches to process simplification for large-area high-resolution TFT-LCDs

Novel process architectures are proposed for fabricating large-area high-resolution TFT-LCDs with a minimal number of process steps. A low contact resistance between Al bus lines and the transparent conductive oxide layer, necessary for large-area panels, is obtained by inducing a self-formed inter-metallic compound layer at the interface without using any additional buffer or capping layers. For enhanced brightness and resolution, a new TFT array structure integrated on a color-filter substrate, referred to as an Array on Color Filter (AOC) structure, has been developed. Good-quality TFTs were successfully constructed on the newly developed color filter for AOC within a sufficiently wide process margin. By adopting these novel technologies, a 15.0-in. XGA prototype panel was fabricated and shows good display performance. Thus, these novel technologies have improved cost efficiency and productivity for TFT-LCD manufacturing, and can be applied to the development of TFT-LCDs of extended display area and enhanced resolution, benefiting from the low resistance bus lines, the high aperture ratio, and reduction in total process steps.