| AVS 54th International Symposium | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS2-WeM |
| Session: | Plasma-Surface Interactions I |
| Presenter: | B. Jinnai, Tohoku University, Japan |
| Authors: | B. Jinnai, Tohoku University, Japan F. Oda, Ushio Inc., Japan Y. Morimoto, Ushio Inc., Japan S. Samukawa, Tohoku University, Japan |
| Correspondent: | Click to Email |
The surface atomic layer chemical reactions must be accurately controlled in future nanometer scale ULSI devices to enable precise patterning without any irradiation damage being caused during plasma etching processes. Many investigations have been conducted to understand surface reactions during silicon etching in chlorine plasma. Such research has focused on the effects of energetic ion and radical species using high-energy ion beam experiments. However, we recently found that the UV photon irradiation from plasma also plays a very important role in surface reactions during silicon etching in chlorine plasma. In this study, we discuss the effects of UV photon irradiation from chlorine plasma during silicon etching with our developed low-energy chlorine atom beam. A silicon substrate was etched by combining a low-energy chlorine atom beam and UV photon irradiation. When the silicon substrate was irradiated to the UV photons from 200 nm to 380 nm during etching with the chlorine atom beam, the etching rate of silicon was drastically increased. The results suggest that UV photons with wavelengths between 200 nm to 380 nm enhance the silicon surface reactions in the chlorine plasma. Additionally, a total photon irradiation density must be greater than 20 mW/cm2 to increase the etching rate of silicon. Namely, the silicon surface reactions strongly depend on the wavelength (the energy) of the UV photons and the UV photon flux in the chlorine plasma. Our results are the first to clarify that UV photon irradiation from plasma plays very important roles in silicon surface atomic layer reactions in chlorine plasma.