| 摘要 |
PROBLEM TO BE SOLVED: To detect the surface state of a substrate located in vacuum, with high sensitivity. SOLUTION: When a pulse laser P is irradiated on the surface of a substrate S, a detection object, a surface oscillatory wave is generated on the substrate S, and the surface oscillatory wave is added to a piezoelectric transducer 33 to thereby output electric charge. The electric charge is converted into an oscillatory wave measuring voltage Vb by a charge amplifier 4, and a voltage waveform is displayed on the screen of an oscilloscope 5. The surface state of the substrate S is determined from the voltage waveform. This method is useful especially for detecting the progressing state of cleaning, when the cleaning of the surface is executed by having the surface of a silicon wafer located in vacuum irradiated with a laser. |
