Noncontact temperature monitoring of semiconductors by optical absorption edge sensing

摘要

noncontact temperature monitoring of semiconductors may be achieved by near infrared reflection spectroscopy of a wafer during processing. A technique is described which relies on the temperature dependence of the optical absorption edge characteristic of most semiconductors in conjunction with internal reflection at the interface between the wafer bulk and the vacuum/dielectric/device. Results are presented which demonstrate application of the technique to silicon wafers with a broad range of back surface properties such as single and double layer dielectrics. The measurements were carried out in situ during process in both a PVD metallization chamber and a plasma etch chamber, over the temperature range from 20 to 570$DGR@C.