| 摘要 |
PURPOSE: To reduce or remove the contamination of a wafer by cleaning fine particles and other contaminants in a chamber by the selective or steep increase of RF power and avoiding the stirring of fine particles in the reaction chamber by the progressive increase of the RF power. CONSTITUTION: A semiconductor wafer 14 is connected electrically to a cathode 13. When an RF signal is generated by an RF signal generator 11 and connected between an anode 12 and the cathode 13 in the reaction chamber 10 by a control circuit 15, plasma is started. The generation and/or circulation of fine particles in the reaction chamber are given as the function of a selective RF-signal power level elevated at a gradient. Since the RF signal is increased at a selected rate for starting plasma, fine particles 16 in the reaction chamber 10 are agitated and circulated at the time of the large rate, and fine particles 16 can be discharged easily from the reaction chamber. Since fine particles 16 are not agitated and circulated at the time of the small rate, the contamination of the wafer treated in the chamber can be suppressed.
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