Process-induced damage by a low energy neutral beam source [etching/cleaning]

Damage studies of direct exposure and photoresist cleaning processes using low energy hyperthermal neutrals are reported. The hyperthermal neutrals are generated by the surface reflection neutralization method. Photoresists and PMMA are used in the removal experiments. Standard gate oxide integrity wafers are used as the test vehicles in quasistatic C-V measurements. The results of this work demonstrate that a low energy neutral source, which provides controllable fast neutrals for cleaning applications, induces much less damage than pulsed plasma sources. The neutral process-induced damage which does occur is a linear function of the reflector bias and RF power, though most of damage is caused by UV photons. Unlike the neutral process damage, which is independent of gas composition, the damage induced by pulsed plasma is a strong function of the gas composition.