Abstract
In this thesis, we investigate the applications of low dielectric constant (low-k) material to multilevel interconnects and to color filter on thin film transistor/liquid crystal display (TFT-LCD) arrays. For multilevel interconnects application, we study the low-k dielectric of porous hydrogen silsesquioxane (HSQ) and PPSZ (porous organo-silsesquiazane). The structural and electrical properties of porous HSQ and PPSZ have been characterized using material analysis tools, such as Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), Auger electron spectroscopy (AES), and electrical meters such as current-voltage analyzer and capacitance-voltage analyzer. The dielectric constant of porous HSQ and PPSZ film was as low as 2.2~2.1 owing to its high porosity and uniformity of the film. A smooth amorphous-like layer including Cu-O-Si bounding is found to form between Cu and the porous HSQ film when the porous HSQ contacts with metallic Cu and being subjected to thermal annealing at 500℃ for 30 min. The mixed layer leads to the increased higher leakage current of the porous HSQ film. In addition, it is even obvious for Cu diffusion into the porous HSQ after thermal annealing at 600℃ for 30 min. Also a smooth amorphous-like layer including Cu-Si bounding is found to form between Cu and the PPSZ film at 550℃ annealing for 30 min. As the time gone by, the Cu-Si layer transformed to SiO2. In the second topic of this thesis, we explore the applications of low-k materials to TFT-LCD technology. The use of colorful low-k dielectrics on TFT-LCD arrays, called COA, can effectively prevent mura and light leakage, leading to high aperture on display. The COA technology, thereby, has attracted considerable attention for application to large–area panel display. The properties of low-k dielectrics for application to COA should be considered including dielectric constant, electrical characteristics, thermal stability and lightness. In this study, two series of low-k films are discussed for COA applications and process conditions are optimized. For the investigation on light property, ITO is used to deposit on the colorful low-k dielectrics as electrode. Because of the transparency, light property of colorful low-k dielectrics could also be investigated. Experimental results have shown the intrinsic properties of the low-k dielectrics are good for TFT-LCD applications in the future.