OVERLAY METROLOGY BY PUPIL PHASE ANALYSIS

• Main Authors: ZAHARAN OFER, MANASSEN AMNON, LEVINSKI VLADIMIR, NEGRI DARIA, SELIGSON JOEL, SAPIENS NOAM, HILL ANDY, KANDEL DANIEL, BACHAR OHAD, BARUCH MOSHE
• Format: Patent
• Language: English
• Published: 21.02.2013
• Subjects: MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

The present invention may include measuring a first phase distribution across a pupil plane of a portion of illumination reflected from a first overlay target of a semiconductor wafer, wherein the first overlay target is fabricated to have a first intentional overlay, measuring a second phase distribution across the pupil plane of a portion of illumination reflected from a second overlay target, wherein the second overlay target is fabricated to have a second intentional overlay in a direction opposite to and having the same magnitude as the first intentional overlay, determining a first phase tilt associated with a sum of the first and second phase distributions, determining a second phase tilt associated with a difference between the first and second phase distributions, calibrating a set of phase tilt data, and determining a test overlay value associated with the first and second overlay target.