| 摘要 |
PURPOSE:To rapidly measure contaminant films scattering on a semiconductor wafer, by detecting an angle of reflection on the semiconductor wafer at the time of generat ing no thermal expansion of the light of a probe, and that at the time of generating the cyclical displacement of the light by the thermal expansion. CONSTITUTION:When excitation light A is projected from a condenser lens system 6, a slope 14 is generated periodically on the surface of the semiconductor wafer 15 by the thermal expansion, setting the center of an irradiation area as an apex. Meanwhile, when probe light B from a probe laser 7 is projected toward a position where the slope 14 is generated, the light B is reflected along a chain line C with an angle theta from the projecting position of the excitation light A at the time of generat ing no slope 14, and is reflected along continuous line C' with an angle theta' on the slope 14 at the time of generating the slope 14. Therefore, the positions of the reflected light C and C' are detected 8, and detected signals P are amplified 9, then, are mea sured by a phase detector 10. Since detected periodic fluctuation on the surface of the wafer 15 varies depending on the presence or absence of the contaminant film, a surface displacement signal varies by the existence of the contaminant film when the scanning stage 16 is scanned in the X or the Y direction or the like, and it is possible to measure the existence of the contaminant film rapidly. |
