Optical metrology system and method

• Main Authors: Barak, Gilad, Shayari, Amir
• Format: Patent
• Language: English
• Published: 09.01.2024
• Subjects: APPARATUS SPECIALLY ADAPTED THEREFOR; CINEMATOGRAPHY; ELECTROGRAPHY; HOLOGRAPHY; MATERIALS THEREFOR; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; TESTING

A measurement system is provided for use in optical metrology measurements. The measurement system comprises a control system which processes raw measured data indicative of spectral interferometric signals measured on a sample in response to illuminating electromagnetic field incident onto a top portion of the sample and comprising at least one spectral range to which said sample is substantially not absorbing. The processing comprises: extracting, from the raw measured data, a portion of spectral interferometric signals describing signal intensity variation with change of optical path difference during interferometric measurements, the extracted signal portion being independent of interferometric signals returned from a bottom portion of the sample in response to said illuminating electromagnetic field; and directly determining, from said extracted portion, both spectral amplitude and phase of reflection of the electromagnetic field from the top portion of the sample, thereby determining measured spectral signature characterizing the top portion of the sample.