| 摘要 |
PURPOSE:To measure in a moment the depth of a minute groove by converting the depth of the minute groove into the distance between mirrors generating two interference peaks in the interference intensity and measuring it and taking an S/N large. CONSTITUTION:Light emitted from a white light source 5 via a lens 8, etc., is separated into two light waves of the reflected light A and the transmitted light B via a beam splitter 9. The reflected light A is reflected totally with a total reflection mirror 11 and transmitted through the splitter 9. On the other hand, the transmitted light B is reflected on an Si substrate 10 to be measured and afterward, reflected on the splitter 9 and joined the previous reflected light A. At this time, since the light source 5 is white, the transmission of the light is regarded as a pulse. Then, there is a delay of 2d in space and 2d/c (c is light velocity and d is depth of the groove) in time between the reflected light pulse 21 from the Si surface and the reflected light pulse 22 from the Si groove base in the reflection on the substrate 10 having the minute groove for forming a capacitor. Accordingly, in case the mirror 11 is moved at a constant speed, the two interference intensity peaks are generated and the depth of the minute groove of the substrate 10 is measured from the interval.
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