| 摘要 |
PURPOSE: A cylindrical sputtering target object, a wiring substrate, and a thin film transistor using the same are provided to slow a sputtering speed in the inner periphery in comparison with that in the outer periphery as the hardness of the cylindrical sputtering target object is gradually increased from the outer periphery to the inner periphery. CONSTITUTION: A cylindrical sputtering target object is formed of oxygen-free copper having purity of 3N or greater and into a cylindrical shape. An orientation rate of a surface is gradually increased from the outer periphery to the inner periphery of the cylindrical sputtering target object as the hardness of the cylindrical sputtering target object is gradually increased from the outer periphery to the inner periphery. Even though the thickness of the sputtering target object is gradually decreased by using the cylindrical sputtering target object, a sputtering speed of the cylindrical sputtering target object is regularly maintained.
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