In FIGS. 6A and 7A, a gate line 113, a gate electrode 121, a common line 117 and a plurality of extended portions 118 and 119 (of FIG. 5) of the common line 117 are formed on a substrate 111 by depositing and patterning one of conductive materials such as aluminum (Al), aluminum alloy, chromium (Cr), molybdenum (Mo) and tungsten (W).