On the role of atomic oxygen in the etching of organic polymers in a radio-frequency oxygen discharge

The kinetics of rise and decay of ground-state atomic oxygen was investigated in a low-pressure O2 radio-frequency discharge. The ground state of O was monitored using laser-induced-fluorescence spectroscopy. The discharge was operated in two modes: a continuous mode and a pulsed mode. Typical discharge settings are rf power of 100 W, a pressure of 10 Pa, and a gas flow of 10 sccm. Using a pulsed mode the behavior of the O density was determined in a pure O2 discharge with no reaction products, and in a discharge during etching of organic polymers. Production and loss mechanisms for O in a pure O2 discharge are discussed. For an O2 discharge during etching of resist it is found that under the given experimental conditions atomic oxygen does not play a significant role in the chemical etch mechanisms involved.