| 摘要 |
PURPOSE:To obtain the stabilized ion beam of high density by a method wherein after a stabilized and high density Kr of Xe plasma has been formed between an electron lead-out electrode and a cathode case by introducing Kr gas or Xe gas into the cathode case, said Kr or Xe gas is replaced with Ar gas slowly. CONSTITUTION:After a stabilized Kr plasma of high density has been formed between an electron lead-out electrode 11 and a cathode case 8 by introducing Kr gas into the cathode case 8, the Kr gas to be introduced into the cathode case 8 is slowly replaced with Ar gas. As a result, a stabilized and high density Ar plasma, having the activation efficiency of reaction gas which is higher than that of the Kr plasma, can be formed between the electron lead-out electrode 11 and the cathode case 8 without increasing the bias voltage of be applied between them, thereby enabling to obtain the ion beam of stabilized and high density reactive gas for the etching performed on the film to be etched. Also, as a W cathode 3 is protected by the Kr and Ar gas introduced into the cathode case 8 in such a manner than the W cathode 3 will not come in contact with the reactive gas contained in an ion source chamber 1, the life of the W cathode can be extended.
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