US 6,982,791 B2
Scatterometry to simultaneously measure critical dimensions and film properties
Jon Opsal, Livermore, Calif. (US)
Assigned to Therma-Wave, Inc., Fremont, Calif. (US)
Filed on Dec. 13, 2002, as Appl. No. 10/319,189.
Claims priority of provisional application 60/346265, filed on Dec. 19, 2001.
Prior Publication US 2005/0041250 A1, Feb. 24, 2005
Int. Cl. G01J 4/00 (2006.01)
U.S. Cl. 356—369 19 Claims
OG exemplary drawing
 
1. An ellipsometric method for evaluating a sample comprising the steps of:
generating a polychromatic probe beam;
polarizing the probe beam;
inducing phase retardations in the polarization state of the probe beam with a compensator, the compensator being substantially non-achromatic so that the amount of phase retardation varies with wavelength;
directing the probe beam against the sample at an angle of incidence between 10 and 50 degrees;
rotating the compensator at an effective angular frequency ω;
passing the probe beam through an analyzer after the probe beam interacts with the sample and with the compensator; and
measuring the intensity of the probe beam after the interaction with the analyzer at a plurality of wavelengths.