APPARATUS AND METHOD FOR OVERLAY MEASUREMENT

摘要

The present disclosure provides apparatus and methods for overlay measurement. An exemplary overlay measurement apparatus includes an illuminating unit, configured to generate light to illuminate a first overlay marker having a first sub-overlay marker along a first direction and a second overlay marker along a second direction; a first measuring unit, configured to receive light reflected from the first overlay marker to cause the reflected light to laterally shift and shear to generate interference light, to receive the interference light to form a first image and to determine existence of overlay offsets along the first direction and the second direction and values of the overlay offset; and a first drive unit connected to the first measuring unit, and configured to drive the first measuring unit to rotate from a first position to a second position to measure the first sub-overlay marker and the second sub-overlay marker, respectively.

主权项

1. An overlay measurement apparatus, comprising:
an illuminating unit, configured to generate light to illuminate a first overlay marker on a wafer having a first sub-overlay marker along a first direction and a second overlay marker along a second direction perpendicular to the first direction to generate reflected light; a first measuring unit, configured to receive the reflected light from the first overlay marker to cause the reflected light to laterally shift and shear to generate interference light, to receive the interference light to form a first image, and to determine existence and values of overlay offsets along the first direction and the second direction according to the first image; and a first drive unit connected to the first measuring unit, and configured to drive the first measuring unit to rotate from a first position to a second position to measure the first sub-overlay marker along the first direction and the second sub-overlay marker along the second direction, respectively.