Patent ID: 11754497

Abstract:
Provided is a method for measuring interstitial oxygen concentration in a silicon wafer easily and sensitively using FT-IR. The invention provides a method for measuring an extremely low oxygen concentration of <1.0×1016 atoms/cm3 in a single-crystal silicon wafer, the method comprising: step 1 of forming a SiO2 film, nitride film or PE film on each of a measurement wafer, interstitial-oxygen-free reference wafer and standard wafer with known interstitial oxygen concentration; step 2 of measuring IR spectra of the three wafers; step 3 of determining a difference transmission spectrum from the IR spectrum of measurement wafer and that of reference wafer and determining the intensity of an absorption peak corresponding to interstitial oxygen; and step 4 of comparing the peak intensity of the interstitial oxygen and that of standard wafer and calculating the interstitial oxygen concentration in measurement wafer from ratio to the interstitial oxygen concentration of standard wafer.