SELF ALIGNING IN-SITU ELLIPSOMETER AND METHOD OF USING FOR PROCESS MONITORING

摘要

An ellipsometric measuring system is set up in association with a vacuum chamber on a production line for thin film samples. The ellipsometer (8) has a scanner (12) for directing the incident light beam to different locations on a thin film sample (11), and the ellipsometer also has an aperture (13) for limiting the reflected light beam (27) received by the photodetector (36). The scanner implements a method of aligning the incident beam to a selected surface of the sample. The scanner and the aperture are used to provide a finer adjustment of the incident beam with respect to the selected surface. The ellipsometric measuring system further uses test thin film samples with known film thicknesses and index or refractions to calculate a value for the angle of incidence of the incident light beam.