Measurement and analysis of grinding wheel surface topography is important because it has a large influence on grinding accuracy. Therefore, a measurement system that can numerically express all cutting edges by image processing has been proposed. Using to this system, it is possible to evaluate the circularity, area of wear-flat, and the presence of external and internal damage. This study aimed to reduce the measurement time by installing a line scan camera. Furthermore, a Voronoi diagram is introduce to obtain new criteria for the distribution of cutting edges and protrusion height. In comparison with the conventional measurement system, measurements and analyses could be performed in a shorter time using this newly developed system. The Voronoi diagram could be applied for these evaluations.

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This study was performed to investigate the relation between removal rate and polishing pad surface temperature in chemical mechanical polishing (CMP) of sapphire substrate (wafer). Contact image analysis was used to evaluate the polishing pad surface asperity. In particular, we examined the following two variables experimentally during sapphire-CMP: (i) the rotational speed of the wafer and the platen (polishing pad), and (ii) the setting temperature of the platen controlled by the chiller unit. This paper discusses the cross-relationships between polishing pad surface temperature, asperity, and removal rate. The results indicated that the hardness and asperity of the polishing pad were affected by changing the pad surface temperature. Furthermore, the removal rate increased with increasing number of contact points between the wafer and the polishing pad.

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Silicon carbide (SiC) is an important semiconductor material for high power electronic applications. However, it is difficult to obtain effective removal rates with chemical mechanical polishing (CMP) of SiC due to its high hardness and strong chemical inertness. In this study, we investigated a high-efficiency CMP process using a high-rotational CMP machine with strong oxidizer slurry. The results showed that it is possible to achieve a high removal rate > 10 μm/h on Si-face (0001) 4H-SiC. Then, we compared the surface quality with that obtained by conventional colloidal silica-based slurry. We examined the usefulness of the two-step CMP process achieving SiC epi-ready surface in a short time, using confocal optical microscopy with differential interference contrast (CDIOM), atomic force microscopy (AFM), and mirror electron microscope (MEM).

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