Optical metrology with multiple angles of incidence and/or azimuth angles

摘要

An optical metrology device simultaneously detects light with multiple angles of incidence (AOI) and/or multiple azimuth angles to determine at least one parameter of a sample. The metrology device focuses light on the sample using an optical system with a large numerical aperture, e.g., 0.2 to 0.9. Multiple channels having multiple AOIs and/or multiple azimuth angles are selected simultaneously by passing light reflected from the sample through a plurality of pupils in a pupil plate. Beamlets produced by the plurality of pupils are detected, e.g., with one or more spectrophotometers, to produce data for the multiple AOIs and/or multiple azimuth angles. The data for multiple AOI and/or multiple azimuth angles may then be processed to determine at least one parameter of the sample, such as profile parameters or overlay error.

主权项

1. An optical metrology device comprising:
a light source that produces a beam of light; an optical system that focuses the beam of light into a spot on a sample, the optical system having a numerical aperture ranging from 0.2 to 0.9, an optical axis of the beam of light is obliquely incident on the sample; a pupil plate having a plurality of pupils all of which simultaneously receive the beam of light after interacting with the sample, wherein a portion of the beam of light passes through each of the plurality of pupils as a beamlet, the plurality of pupils being arranged to produce beamlets at a plurality of at least one of angles of incidence and azimuth angles; at least one detector positioned to receive the beamlets; and a processor coupled to receive data from the at least one detector for the plurality of at least one of angles of incidence and azimuth angles, the processor configured to determine at least one parameter of the sample based on the data for the plurality of at least one of angles of incidence and azimuth angles.