Radiation Damage Evaluation in Excimer Laser Beam Irradiation and Reactive Ion Etching

In the course of studying UV-light excited etching, it was found that high-energy ArF excimer laser (193 nm, 6.4 eV) irradiation induced neutral electron traps in a SiO2 film of a MOS capacitor. The trap generation origin was verified to be the excitation of impure OH and Si bonds by the irradiation of an ArF laser beam propagated in the SiO2 film under a poly-Si electrode. It is proposed that Si ions, which released OH radicals during laser irradiation, act as electron traps. Furthermore, by manufacturing MOSFETs, RIE and ArF laser-irradiation damage was compared. Persistent damage induced during RIE on gate material was found to remain to the last.