Hideo Shibutani

Study on Manufacturing of Mirror Grinding Wheel for Environmental Awareness. Development of Guiding Principle Based on a Grinding Mechanism.

Until now, the criteria to evaluate the processing technique have been mainly lying in the aspects of cost, accuracy, quality, efficiency and stability. With the criterion on environmental contamination added in, the realization of the environmental harmony type of processing technique is becoming an important topic. As the first step of this research, this paper aims to find out the fundamental guideline in developing a harmless grinding wheel, which may be used in the mirror grinding of the silicon. Harmless materials for human being were selected as the constituent materials. Sodium alginate was used as the bonding agent and barium sulfate was used as the abrasive grain. The performance of the wheel was investigated by the grinding of the 8-inch silicon wafer. In dry grinding, a stable mirror surface with around 10nm roughness (Ry) was obtained, and the processing strain was very small, furthermore, small acicular silicon was observed in the grinding chips. However, toxic SO3 was detected in the gas arising in the grinding process. By this new method, the grinding wheel that basically met the conventional was prototyped experimentally. The mechanochemical reaction, which is usually difficult to be proved, can be easily confirmed by the happening of noxious gas. It also clarified that although the grinding wheel was made of harmless material, noxious material happened from mechanochemical reaction.