Copper self-sputtering by planar magnetron

Aiming at filling up deep holes with metal, self-sputtering of copper is performed in a wide pressure range of 10-2Pa to 10-4Pa. The high target current of 7 A to 10 A for a 4-inch planar magnetron target is essential to perform the self-sputtering process wherein a very high deposition rate of about 4 μm/min at 60 mm from the target surface is obtained. The lifetime of the planar target is from 1 h to 2 h. A new type of target which has protuberances on the erosion centers is produced by trial and error, and achieved a lifetime of 4 h. Deep holes on Si wafers, 1.17 μm in depth and 0.4 μm or 0.6 μm in diameter, are examined, and very good bottom coverage of nearly 100% is obtained. (author)