新部 正人

我々は、これまで熱分解BNターゲットを高周波スパッタしてc-BN薄膜を成長させることを試みてきている。系統的に成膜条件を変化させて実験を行った結果、スパッタガスとして純Arを用いた場合とAr+N2混合ガスを用いた場合でc-BNの成長する条件が大きく異なることを見出した。本報告では、それらの結果を示しながら、スパッタガス種が及ぼす影響について検討する。

スパッタ中の基板に降り注ぐイオンの量とエネルギーは、マグネトロン周囲に巻いたコイルの電流や基板バイアス電圧によって制御できる。これらを変化させてBN薄膜を成長させた結果、どちらも薄膜のc-BN相含有率に影響を及ぼすことがわかった。また、基板そのものもc-BN相の含有率に影響があり、超硬合金基板上でc-BN相が生成する条件はSi基板に比べてより高エネルギー側にシフトすることも明らかとなった。

To estimate the optics lifetime of an extreme ultraviolet lithography (EUVL) system with a contaminated mirror surface, it is indispensable to carry out an acceleration test using high-flux EUV irradiation. In this study, Mo/Si multilayer mirrors were irradiated in various vacuum environments using a contamination evaluation system with an undulator light source, and changes in their reflectivity were evaluated. The dependence of the decrease in reflectivity per unit dose on the EUV irradiance was observed in high-flux irradiation experiments in vacuum with water vapor or n-decane gas introduction at pressures lower than about 10^{-5} Pa. The irradiance dependence disappeared when the pressures were increased for both water vapor and decane gas. A reflectivity distribution with a doughnut shape, namely, high at the irradiation center, low in the surrounding area, and high in the non-irradiated area, was observed in the irradiation experiments during the simultaneous introduction of water vapor and decane gas. These results can be generally explained by the mechanism of the supply-controlled limit.

The effects of thermal annealing of W incorporated diamond-like carbon (W-DLC) films fabricated with focused ion beam chemical vapor deposition (FIB-CVD) were investigated using X-ray absorption fine structure near the carbon K-edge (C-K NEXAFS) and the combination of Rutherford backscattering (RBS) and elastic recoil detection analysis (ERDA). W-DLC films were annealed for 32 h at temperatures, T_{\text{a } }, between 673 and 1073 K. Comparing the T_{\text{a } } dependences of Ga and H contents obtained from RBS-ERDA and the \mathrm{sp}^{2}/(\mathrm{sp}^{2} + \mathrm{sp}^{3}) ratios from C-K NEXAFS, it was found that even a trace amount of W incorporation into DLC films fabricated by Ga+ FIB-CVD may cause a significant \mathrm{sp}^{3} \rightarrow \mathrm{sp}^{2} structural change.

我々は、h-BNターゲットをRFスパッタしてc-BN相を含む薄膜の形成を試みている。今回は、基板バイアス電圧を主たるパラメータとし、基板温度、スパッタガス圧の影響についても併せて調査した。その結果、80V以上のバイアス電圧を印加することで、c-BN相を含む薄膜が得られることがわかった。また、その含有割合は、基板温度が高いほど、またスパッタガス圧が低いほど多くなる傾向が認められた。

The desorption processes of H and Ga from diamond-like carbon (DLC) film synthesized by focused-ion-beam chemical vapor deposition (FIB-CVD) were investigated by elementary analysis and local structure analysis after heat treatment under various conditions. The elementary composition of FIB-CVD DLC film was determined using a combination of Rutherford backscattering spectra and elastic recoil detection analysis spectra. Local structure analysis was performed by the measurement of near-edge X-ray absorption fine structure using synchrotron radiation. Desorption of H from FIB-CVD DLC film by heat treatment was found to comprise two types of process. One is the local graphitization along paths, where residual Ga atoms move by annealing. In this process, Ga acts as a catalyst for the graphitization of DLC. The other process is derived from the graphitization of the whole DLC film by heat, regardless of Ga. In this process, the sp2 content increases considerably.