| 摘要 |
PROBLEM TO BE SOLVED: To provide an etching system which is capable of substantially protecting an upper electrode from corrosion even if dry cleaning for removing deposits from the upper electrode is reduced to an irreducible minimum or dispensed with. SOLUTION: An upper electrode (anode) 14 coated with polymer deposits in an normal operation is self-cleaned through 21 control method related to a plasma etching reactor. In one practical method, RF plasma is used for continuously feeding an electric power through the intermediary of a lower electrode, and an RF power much smaller than a main RF power which generates and keeps plasma in an etching reactor 10 is applied to the upper electrode 14. The small RF power is so set at a certain power level so as to continuously remove the deposits from the upper electrode 14 but not to remove the electrode material. In another practical method, an electrical power is intermittently applied to the upper electrode 14 in a cleaning period, and no electrical power is applied to a lower electrode 12 in a cleaning period. These two cleaning methods may be combined, or a continuous cleaning is complemented with an intermittent cleaning in an interruption period in a etching process.
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