A Method for Quantitative Evaluation of Electrical Conductivity of Silicon Wafers by Millimeter-Waves

摘要

We present a method for quantitative measurement of electrical conductivity of semiconductor wafers in a contactless fashion by using millimeter-waves. A focusing sensor was used to focus a 110 GHz millimeter-wave beam on the surface of a silicon wafer. The amplitude and the phase of the reflection coefficient of the millimeter-wave signal were measured by which electrical conductivity of the wafer was determined quantitatively, independent of the permittivity and thickness of the wafers. The conductivity obtained by this method agrees well with that measured by the conventional four-point-probe method.