Plasma processing method and plasma processing apparatus

Abstract

A plasma processing apparatus for processing a substrate placed on a sample base installed in a vacuum processing chamber, in which plasma is generated and a high-frequency voltage is applied to the sample base. The apparatus includes a high-frequency power supply connected to the sample base, a modulation unit for periodically carrying out on-off modulation on the high-frequency voltage generated by the high-frequency power supply, and a control unit for changing a duty ratio of the on-off modulation for each processed substrate or each plurality of processed substrates.

1 . A plasma processing apparatus for processing a substrate placed on a sample base installed in a vacuum processing chamber, in which plasma is generated and a high-frequency voltage is applied to the sample base, comprising: 
 a high-frequency power supply connected to the sample base;    a modulation unit for periodically carrying out on-off modulation on the high-frequency voltage generated by the high-frequency power supply; and    a control unit for changing a duty ratio of the on-off modulation for each processed substrate or each plurality of processed substrates.    
   
   
       2 . A plasma processing apparatus for etching a substrate by using an ECR, comprising: 
 vacuum processing chamber;    an antenna placed on the top of the vacuum processing chamber, and connected to a high-frequency power supply for generating an ECR plasma in the vacuum processing chamber;    a lower electrode provided, in the vacuum processing chamber so as to face the antenna;    another high-frequency power supply connected to the lower electrode;    a modulation unit for periodically carrying out on-off modulation on the high-frequency voltage generated by the another high-frequency power supply; and    a control unit for changing a duty ratio of the on-off modulation for each processed substrate or each plurality of processed substrates.