Quantitative Infrared Spectroscopy of Interstitial Oxygen in Silicon Wafers Using Multivariate Calibration

A PLS multivariate calibration method is used to create a reliable means for the determination of the interstitial oxygen content in silicon wafers. The multivariate calibration, derived from silicon standards with various backside treatments, provides similar precision measurement capability when compared to peak area calibration curves established from individual backside treatments. In this case, the significant advantage of the multivariate calibration is that a single calibration can yield interstitial oxygen results that correlate favorably with vendor values over a wide range (20 to 40 ppma), regardless of the backside condition of the wafers.