Manpower Obsolescence: A New Definition and Empirical Investigation of Personal Variables.

In this investigation, a low cost Si wafer metrology system based on low coherence interferometry using NIR light is proposed and verified. The whole system consists of two low coherence interferometric principles: low coherence scanning interferometry (LCSI) for measuring surface profiles and spectrally-resolved interferometry (SRI) to obtain the nominal optical thickness of the double-sided polished Si wafer. The combination of two techniques can reduce the measurement time and give adequate dimensional information of the Si wafer. The wavelength of the optical source is around 1 μm, for which transmission is non-zero for undoped silicon and can be also detected by a typical CCD camera. Because of the typical CCD camera, the whole system can be constructed inexpensively.