| 摘要 |
PURPOSE:To detect the foreign matter sticking onto a substrate with high sensitivity by coating the surface of the substrate with a material having >=70% reflectivity to light. CONSTITUTION:Al is deposited by sputter evaporation to about 50nm (91% reflectivity to He-Ne laser light) on the mirror surface side of, for example, an Si wafer (about 4 inch diameter) of which at least one face is finished to the specular surface. Such wafer is immersed into a standard particle suspension (for example, 10<5> pieces/ml particle concn. and 0.33mum particle size) and after drying, the number of the foreign matter on the wafer is measured by using an instrument for measuring the stuck foreign matter (using the He-Ne laser). The particles of the respective particle sizes on the Si wafer can be detected with the detection voltage lower by about 110V than on the Al deposited wafer. The 0.109mum particles cannot be detected on the Si wafer but can be detected at about 1,300V on the Al deposited wafer. The very small foreign matter on the substrate is, therefore, detected with the high accuracy by covering the substrate surface with the material having >=70% reflectivity to light. |
