A water-film chuck utilizing meniscus force has been developed to flatten highly warped concave wafers and to achieve high TTV (Total Thickness Variation) within 0.3 μm. This paper describes thinning methods of a water film, the spin conditions to form a water film of less than 100 nm and the experimental resuls of the wafer thinning by grinding with the water-film chuck. A water film was formed with the method in which the chuck is spun at high speed after interposing water between the chuck and a specimen. When the spinner rotation speed is 5000 min^-1 and the rotation time is more than 300 s, the thickness of a water film becomes less than 100 nm over the entire surface of a 300 mm wafer. The thickness becomes thinner and more uniform with increasing the rotation speed and the rotation time. From the results of observation for two months, it was clarified that the thickness of a water film of less than 100 nm do not almost change and the uniformity of that is maintained. Furthermore, by using the water-film chuck, it was possible to thin a 300 mm silicon wafer from 725 to 30 μm with a TTV of less than 0.8 μm equivalent to that obtained using a porous vacuum chuck.

Double-sided polishing (DSP) method is widely used in manufacturing process of sapphire substrate for LEDs. Since, several studies on the DSP method have been actively reported, however, it is not enough from the practical viewpoint such as the effect of carrier, polishing pad surface asperities and kinematic friction characteristics on the removal rate. This study focuses on the carrier used in the DSP as well as aims to elucidate the carrier characteristics and the kinematic friction coefficient for obtaining the high removal rate. In this paper, the effects of slurry hole area ratio and surface properties of carrier on the removal rate in upper/ lower surfaces of substrate were examined. Moreover, in the kinematic friction characteristics between the polishing pad and the substrate, the friction characteristics in the DSP were observed. As a result, the removal rate and kinematic friction coefficient of the upper/ lower surfaces of substrate change depending on the slurry hole area ratio and surface properties of carrier, and there is a strong relationship between them.

Vascular walls change their dimensions and mechanical properties in pathological condition under hormonal and biomechanical stimuli, and such changes are generated by smooth muscle cells in the vascular tissues. Thus cellular mechanical properties are quite important for understanding the mechanism of vascular disease. Recent researches demonstrated the measurement of surface local mechanical properties of a single cell level using micro engineering technology, such as an atomic force microscopy and optical tweezers. However, it is unclear the mechanical properties of cells in a wide rage of strain and cell-substrate adhesion strength which is quite important for the muscle cell mechanics in tissue. Here we developed a novel cell micro tensile tester, and investigated the tensile stiffness and adhesion strength of vascular smooth muscle cells. We assessed the correlation between whole cell stiffness, adhesion strength, and the cell spreading area. The cell adhesion strength has a positive correlation with cell spreading area. On the other hand, cell tensile stiffness was almost constant even though morphological dimensions of cells were quite varied. These results indicate that vascular smooth muscle cells keep their tensile stiffness constant to sustain vascular wall strength. Our micro tensile tester should be a powerful tool in investigating cellular mechanical functions.