Ultra-low thermal expansion materials are among the most important for making ultra-precision parts such as large telescope mirrors, ring laser gyroscopes, optical flats as well as lithography systems. All such applications are for static or quasi-static parts, except for one case of a grinding spindle used at high rotational speed, although this spindle was broken after 6 years of operation. Since such materials can be casted to the near-net-shape, the properties of the material itself is one of the most important factor in making high precision dynamic and static parts in future. So, the adequate finishing process and fracture strength of the material should be clarified. Zerodur, Neoceram N-0 and sintered Zerodur were cut by grinding and finished by various methods such as grinding, polishing and etching into 4-point bending test samples of 4mm width, 3mm thickness, and 45mm length. The flexural strength of Zerodur and Neoceram N-0 is influenced by the finished surface roughness and residual micro-cracks left over from cutting and conventional grinding. Float-polished samples show the highest flexural strength, the value of which is much higher than alumina ceramics. The flexural strength of sintered Zerodur is not improved by precision finishing due to pores in the bulk.

In most semiconductor manufacturing processes, the wafer is processed in vacuum. It is important to achieve optimal wafer temperature control during fabrication to ensure high precision. Therefore, for optimal thermal design, it is necessary to analyze the characteristics of thermal contact conductance in vacuum. In this study, the characteristics of low contact pressure region (less than 50 kPa) were evaluated with SUS304 stainless steel to simulate typical wafer chucking conditions, such as electrostatic chucks. The thermal contact conductance of direct-contact and gas components were examined separately. The results showed that, except for the low contact pressure region, the thermal contact conductance of the direct-contact component increased linearly with the contact pressure. It is assumed that the direct-contact component was affected by the asperities of the contact surface, particularly in the low contact pressure region. Conversely, in vacuum under the free molecular flow region, the thermal contact conductance of the gas component was not affected by the contact pressure. It is assumed from the results that the robustness of the thermal contact conductance in vacuum can be enhanced by increasing the gas pressure within the free molecular flow region.

Zinc oxide (ZnO) has semiconductor properties and is applicable to gas sensors. The principle of gas sensing is the exchange of electrons between ZnO structure and gas molecules. Thus, effective passageway of electrons in the structure is required in the structure in addition to the increase in surface area. Gathered urchin-like structure will makes many contacts points utilizing their needles. This paper proposes a two-step fabrication process. In the first step, ZnO particles (φ100 nm) were dispersed in aqueous suspension and a substrate was drawn up from it to produce self-assembly structure as nuclei. In the second step, ZnO needles were synthesized or grown on each ZnO particle of the assembly by hydrothermal method in which source materials were filled in an autoclave together with water. The morphology changed drastically depending on the conditions. Thus, systematic experiments were carried out and the appropriate conditions were made clear. Finally, gas sensing property of the structure was examined and higher sensitivity of the urchin-like structures compared to ZnO assembled particles was confirmed.

Hydrocarbon monomolecular films were prepared on a glass slide with a chemical adsorption technique. Water-repellent fluorocarbon monomolecular films were prepared by CF₄ plasma treatment on the chemically adsorbed hydrocarbon monomolecular films. However, the monomolecular films were usually removed by sputtering when the CF₄ plasma was treated, because CF₄ plasma contains ions of the fluorocarbon fragments, not only its radicals. Therefore, fluorocarbon ions were removed from the plasma by mesh connected to the earth, and then only fluorocarbon radicals were used for treatment in order to prevent the monomolecular film from being removed. Fourier-transform infrared reflection absorption spectroscopy (FTIR-RAS) revealed that the hydrocarbon groups or hydrogens of the hydrocarbon monomolecular film were substituted with fluorocarbon or a fluorocarbon radical. In addition, the water drop contact angle of the film slightly increased by the treatment. It was demonstrated that water-repellent monomolecular films can be prepared by CF₄ plasma treatment on hydrocarbon monolayers. Thus, the plasma treatment technique may be useful into preparing the highly durable fluorinated monomolecular films with the cross linkage inter adsorbed molecules in the monolayer films.

Silicon wafers as the most commonly used substrates for semiconductor devices are strongly required to be manufactured with superior flat surface, that is, small thickness variation to obtain high productivity and performance of the devices. The double-sided polishing (DSP) process is widely adopted as the finishing stage of the wafer manufacturing, because wafers with good surface quality and flatness can be obtained economically. To achieve further good surface flatness of wafers in DSP process with good reproducibility, we investigated a kinematics-based DSP simulation model considering the friction between wafer and pads, the friction between wafer and carrier hole and the pressure distribution on the wafer. On the basis of the simulation model, polishing conditions, in concrete, a set of rotation conditions of upper/lower platens and inner/outer gears were optimized to reduce thickness variation of wafers. DSP experiments on silicon wafers with a diameter of 300 mm revealed that the optimized condition achieved small thickness variation of wafers stably without singular shape.

Under atmospheric pressure, homogeneous non-equilibrium barrier discharge was generated stably using high voltage pulsed power (1 kV, 20 kHz) excitation of helium and oxygen gases. Source material Zn-MOPD (2-methoxy-6-methyl-3, 5-heptanedionate Zinc) was fed into this glow discharge cold plasma. Transparent uniform ZnO films about 172 nm of thickness were fabricated on glass slides at the substrate temperature of 400℃. In this paper, we investigate the effects of He and O₂ plasma treatment or He plasma treatment on ZnO thin films. The average transmittance of as-deposited film and the films after plasma treatment was about 90% with wavelengths ranging from 400 to 800 nm. X-ray diffraction measurement revealed that ZnO films had a c-axis oriented poly-crystalline structure. Their crystallinity improved by plasma treatment. By increasing the time of He and O₂ plasma treatment, electrical resistivity increased from 0.50 Ωm to 7.9 Ωm at 60 min. However, by increasing the time of He plasma treatment, electrical resistivity decreased into 0.053 Ωm at 60 min. FE-SEM observations show a change in the grain size of the columnar microstructure of the film. These results suggest that He plasma treatment or He and O₂ plasma treatment change the microstructure of the film and then electrical resistivity changes.

Aiming the use in an optical image stabilizer for smart phone cameras, a two-degree-of-freedom micro actuator consisting of a thin permanent magnet having a fine pitch chessboard magnetic pattern, a two-layer printed-coil and a silicon elastic guideway was proposed and fabricated. The permanent magnet of 9.1 x 9.1 x t 0.5 mm was processed by wire electric discharge machining to minimize the damage of the magnetic properties. The permanent magnet with lattice-patterned grooves for thermal insulation was multi-pole-magnetized by laser assisted heating. The elastic guideway was machined using deep reactive ion etching. The driving forces of 1.24 and 1.66 mN and the positioning ranges of 211 and 282 μm in the X and Y directions, respectively, were obtained with a coil current of ±0.1 A in each layer coil.