A substrate supporting thin film transistors thereon, each including a semiconductor layer and source-drain electrodes, wherein the source-drain electrodes are formed from a nitrogen-containing layer or oxygen/nitrogen-containing layer and a thin film of pure copper or copper alloy. The nitrogen-containing layer or oxygen/nitrogen-containing layer has respectively part or all of its nitrogen or part or all of its oxygen or nitrogen connected to silicon in the semiconductor layer of the thin film transistor, and the thin film of pure copper or copper alloy is connected to the semiconductor layer of said thin film transistor through the nitrogen-containing layer or oxygen/nitrogen-containing layer.