Patent ID: 6642149
Filing Date: 2003-11-04
Classification: H01J

Abstract:
In a plasma processing method for transforming process gas into plasma, in a vacuum processing chamber, by superposing and applying a first high frequency power component of a frequency (f1) and a second high frequency power component of a frequency (f2) which is lower than the frequency (f1), to an electrode, and processing an object to be processed placed on the electrode by said plasma,the improvement in that said frequency (f2) is controlled to such a frequency that ions in the plasma are not accelerated by changes in an electric field in the processing chamber generated by the second high frequency power component, wherein the frequency (f2) is a frequency higher than an ion plasma frequency of ions in the plasma, and wherein the ion plasma frequency of ions in the plasma is (e2&it;no/&varepsilon;o&it;M)1/22&it;Ï€wherein e is an electric charge amount of electrons, no is a plasma density, M is a mass of ions, and âˆˆo is a dielectric constant in vacuum.