A thickness measurement system may include an illumination source, a beam splitter to split illumination from the illumination source into two beams, a translation stage configured to translate a reference sample along a measurement direction, a first interferometer to generate a first interferogram between a first surface of a test sample and a first surface of the reference sample, and a second interferometer to generate a second interferogram between a second surface of the test sample and a second surface of the reference sample. A thickness measurement system may further include a controller to receive interference signals from the first and second interferometers as the translation stage scans the reference sample, and determine a thickness of the test sample based on the thickness of the reference sample and a distance travelled by the translation stage between peaks of envelopes of the interference signals.
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