| 摘要 |
PURPOSE:To prevent the sticking of fine powder to a dot periphery and to clean the base plate surface after marking by immersing a base plate into a liquid, irradiating the base plate surface with a laser beam and dotting a mark. CONSTITUTION:A wafer 1 is immersed into pure water 10 put in vessel 11 and the wafer 1 surface is irradiated with the laser beam B and the mark is dotted. Further, the thickness of the pure water 10 to cover the wafer 1 is regulated to 1-2mm and the laser beam output is regulated so that the mark is dotted. Consequently, vapor (fine powder) generated by melting with the instant dot irradiation is made to the isolated fine powder in the pure water and prevented from being stuck to the wafer surface. |
