| 摘要 |
PROBLEM TO BE SOLVED: To enable a uniform cleaning process to be carried out causing the least damage to a substrate by a method wherein a plasma processing device is used in the cleaning process, a plasma generating power is gradually increased to a prescribed power value, then a prescribed substrate bias voltage is applied, and the substrate is subjected to sputter etching. SOLUTION: A plasma processing device generates plasma between a counter electrode and a grid electrode and controls the incident energy of ions that impinge on a substrate independently of the input level of a plasma generating power supply. In this case, plasma whose density is of the order of 1010 cm-3 can be obtained. By this plasma processing device, a natural oxide film 5 on the surface of a lower conductive layer 4 that comes out of the base of a connecting hole 7 is cleaned by sputter etching. At this point, a plasma generating power is gradually increased to a prescribed value, and then a prescribed substrate bias voltage is applied. Moreover, it is preferable that sputter etching is carried out by the use of non-oxidizing gas.
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