Appeal No. 2006-0741
Reexamination Control No. 90/006,185
wavelength fixed) and to changes in the wavelength (with the angle of
incidence fixed). See, p. 3217, second column, 1st full paragraph, and see
Abstract. Moharam also studies the sensitivity of the diffraction gratings
to the polarization (TE or TM) of the incident light. See, p. 3217,
paragraph bridging 1st and 2nd columns.
The examiner has articulated no basis to discredit the above-quoted testimony of Mircea Dusa.
Raymond discloses a system and method for determining the widths and overall profiles
of dielectric grating lines by measuring the intensity of diffracted laser light from the sample
substrate over a specified range of incident beam angles (Raymond, page 1484, Introduction).
As is determined correctly by the examiner (Answer at 4), Raymond discloses comparing the
predicted diffraction intensity over the range of incident beam angles as calculated through a
mathematical algorithm applied to a model to the actual measured diffraction intensity
(Raymond, page 1485, column 2, lines 9-49). But the wavelength of incident illumination is
fixed and the diffraction intensity is not measured as a function of wavelength. Raymond’s
system and method depend on measuring the diffraction intensity as a function of a varying
incident angle. As is stated in Raymond on page 1485, column 2, lines 46-54:
The sample is mounted on a stage that permits it to rotate. Since the beam itself is
fixed, this rotation changes the angle of incidence on the sample. Using grating
Eq. (1), the detector arm of the scatterometer is able to follow any diffracted order
as this angle is varied. The intensity of a particular diffraction order as a function
of incident angle, which is known as 2-t plot or scatter “signature,” is then
downloaded to a computer, where the analysis can begin.
The wavelength of Raymond’s incident laser is not changed when the incident angle is changed.
Similarly, in Moharam, as is discussed above, while the angle of incidence is changed, the
wavelength of the source illumination stays fixed.
10
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: November 3, 2007