INTERNAL WIRING OF SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a high-purity single crystal copper which, when formed into a film and applied as a wiring onto an Si substrate, can give a semiconductor device having fine wirings highly resistant to corrosion in virtue of the merits, i.e., EM resistance and SM resistance, of copper, to provide a sputtering target made from the obtained single crystal copper, and to provide a semiconductor element having a wiring made from a film of the target. SOLUTION: High-purity copper having a purity of at lowest 99.9999 wt% and having a total content of silver and sulfur of at highest 0.1 ppm is used as a starting material. This is placed in a raw material crucible 5 set in an electric furnace 1 and is melted. The molten copper is dropped into a lower single crystal mold 6 through a molten copper drop port 4 on the bottom of the crucible 5. In the meantime, the temperature is controlled by means of middle and lower heaters 10, 11 and 12, and the quartz cylinder 3 is evacuated by means of a vacuum system 2. The furnace 1 has on its bottom a heat-insulating trap 8 surrounded with a water-cooling flange 7 through which cooling water 9 passes. The high-purity single crystal copper desirable as a target material for forming a wiring in a semiconductor element accumulates in the single crystal mold 6 of this apparatus. COPYRIGHT: (C)2006,JPO&NCIPI