Mechanistic studies of oxygen plasma etching

Oxygen dissociation was measured in reactive ion etching (RIE) plasmas using a quadrupole mass spectrometer which sampled the particle flux through a pinhole in the lower electrode of a parallel-plate reactor. The oxygen atom flux increased with increasing power and generally decreased with increasing pressure. Ion currents and bombardment energies also decreased with increasing pressure, while the etch rate of novolac resists increased. In the low-pressure (20–75 mTorr) regime of oxygen RIE plasmas, etch rates of novolac polymers correlated most directly with the supply of oxygen molecules to the surface.