Using surface wave produced plasmas to determine the frequency effect upon etching of polyimide in RF and microwave sustained plasmas

A novel high frequency plasma reactor capable of plasma processing over a wide range of frequencies under otherwise identical conditions is described. This reactor was used to investigate the influence of the plasma stimulating frequency from 13.56 to 2450 MHz, upon the etch rate of polyimide in an O2-CF4 plasma. Significant variations of the etching characteristics of polyimide with frequency were found which are attributed to a variation of the electron energy distribution function: independent actinometric data in the same reactor show a similar variation of the atomic oxygen concentration in the gas phase. © 1989.