Patent ID: 7787134

Claim:
A metrology system comprising: a scanner configured to rotate a first fanned probe beam and a second fanned probe beam about a scan axis with respect to a common origin for the first and second fanned probe beams, wherein the first fanned probe beam extends in a first direction and in a second direction, the first and second directions and the scan axis all being orthogonal to each other, and wherein the rotation of the first fanned probe beam about the scan axis defines a first scan angle, the first fanned probe beam being tilted with respect to the second direction by a first tilt angle, and wherein the second fanned probe beam extends in the first and second directions and is tilted with respect to the second direction by a second tilt angle that differs from the first tilt angle, the rotation of the second fanned probe beam about the scan axis defining a second scan angle, the first fanned beam being collinear with the second fanned probe beam, a light source system configured to generate the first fanned probe beam having a first wavelength and a first modulation frequency, the light source system further configured to generate the second fanned probe beam having a second different wavelength and a second different modulation frequency; and a position detection module configured to receive a first reflected return beam having the first wavelength and first modulation frequency from a first target and to receive a second reflected return beam having the second wavelength and the second modulation frequency from the first target and configured to determine a position of the first target using a range and the first scan angle associated with the first return beam and a range and the second scan angle associated with the second return beam.