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UV radiation during plasma processing affects the surface of materials. Nevertheless, the interaction of UV photons with surface is not clearly understood because of the difficulty in monitoring photons during plasma processing. For this purpose, we have previously proposed an on-wafer monitoring technique for UV photons. For this study, using the combination of this on-wafer monitoring technique and a neural network, we established a relationship between the data obtained from the on-wafer monitoring technique and UV spectra. Also, we obtained absolute intensities of UV radiation by calibrating arbitrary units of UV intensity with a 126 nm excimer lamp. As a result, UV spectra and their absolute intensities could be predicted with the on-wafer monitoring. Furthermore, we developed a prediction system with the on-wafer monitoring technique to simulate UV-radiation damage in dielectric films during plasma etching. UV-induced damage in SiOC films was predicted in this study. Our prediction results of damage in SiOC films shows that UV spectra and their absolute intensities are the key cause of damage in SiOC films. In addition, UV-radiation damage in SiOC films strongly depends on the geometry of the etching structure. The on-wafer monitoring technique should be useful in understanding the interaction of UV radiation with surface and in optimizing plasma processing by controlling UV radiation.

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A two-dimensional simulation of dc magnetron discharge is performed by a hybrid of fluid and particle models. In this hybrid model, ions and bulk electrons are treated by the fluid model and fast electrons are treated by the particle model. The numerical results indicate that the number density of the fast electrons has little effect on the electric field distribution in dc magnetron discharge at 30 mTorr since the ratio of fast electrons to bulk electrons is quite low. The transport of fast electrons is, however, quite important for dc discharge because the spatial distribution of the net ionization rate is subject to the spatial behavior of the fast electrons.

Highly selective, highly anisotropic, notch-free, and charge-buildup damage-free silicon etching is performed using electron cyclotron resonance (ECR) Cl2 plasma modulated at a pulse timing of a few tens of microseconds. A large quantity of negative ions are produced in the afterglow of the pulse-time-modulated plasma. The decay times of electron density, electron temperature, and sheath potential are considerably reduced. This is attributable to negative-ion generation. Furthermore, the pulse-time-modulated plasma reduces the time averaged sheath potential. As a result of these effects, charged particles in the sheath are drastically modified from the continuous discharge, and they should improve the selective etching in the pulsed ECR plasma and eliminate charge accumulation on the substrate. Additionally, negative-ion generation dramatically improves the plasma potential distributions in the nonuniform ECR plasma. This technique is also suitable for large scaled etching processes.