| 摘要 |
An ellipsometer includes a light source for generating a probe beam of polychromatic light for interacting with a sample. A polarizer is used to impart a known polarization state to the probe beam and the polarized probe beam is directed against the sample at a shallow angle of incidence. A rotating compensator is used to impart phase retardations to the polarization state of the reflected probe beam. After passing through the compensator, the probe beam passes through a second polarizer (analyzer). After leaving the analyzer, the probe beam is received by a detector. The detector translates the received probe beam into a signal that includes DC, 2omega and 4omega signal components (where omega is the angular velocity of the rotating compensator). A processor analyzes the signal using the DC, 2omega and 4omega components allowing simultaneous evaluation of both critical dimensions and film parameters.
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