US 12,392,733 B2
Combined ocd and photoreflectance method and system
Yonatan Oren, Kiryat Ono (IL); and Gilad Barak, Rehovot (IL)
Assigned to NOVA LTD., Rehovot (IL)
Appl. No. 17/758,067
Filed by NOVA LTD., Rehovot (IL)
PCT Filed Dec. 24, 2020, PCT No. PCT/IL2020/051331
§ 371(c)(1), (2) Date Jun. 27, 2022,
PCT Pub. No. WO2021/130757, PCT Pub. Date Jul. 1, 2021.
Claims priority of provisional application 62/953,640, filed on Dec. 26, 2019.
Prior Publication US 2023/0035404 A1, Feb. 2, 2023
Int. Cl. G01N 21/956 (2006.01); G01B 11/02 (2006.01); G01N 21/88 (2006.01); G01N 21/95 (2006.01); G03F 7/00 (2006.01); H01L 21/66 (2006.01)
CPC G01N 21/956 (2013.01) [G01B 11/02 (2013.01); G01N 21/9501 (2013.01); G03F 7/70625 (2013.01); H01L 22/12 (2013.01); G01N 2021/8835 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A combined OCD and photoreflectance apparatus for improving the OCD performance in measurements of optical properties of a target sample comprising:
(a) either a single channel OCD set-up comprised of a continuous single probe beam configured in a direction normal/oblique to the target sample or a multichannel OCD set-up having multiple continuous probe beams configured in normal and oblique directions to the target sample for measuring the optical properties of the target sample in said normal direction and/or in said oblique direction;
(b) at least one laser source for producing at least one laser beam;
(c) at least one modulation device to turn the at least one laser beam into at least one alternatingly modulated laser beam, and thus, to allow said at least one alternatingly modulated laser beam to alternatingly modulate the spectral reflectivity of the target sample, so that, at least one light beam reflecting off said target sample is alternatingly a “pump on” light beam and a “pump off” light beam; and
(d) at least one spectrometer for measuring spectral components of the at least one light beam reflecting off said target sample;
wherein said at least one light beam that is reflecting off the target sample is directed into said at least one spectrometer, and wherein said at least one alternatingly modulated laser beam is alternatingly modulating the spectral reflectivity of the target sample; and
wherein the combined OCD and photoreflectance apparatus is configured to:
operate in first measurement mode for providing OCD related measurements related to spectral components of the at least one light beam reflecting off said target sample when the light beam reflecting on the sample is the “pump off” light beam, and
operate in a second measurement mode providing photoreflectance related measurements related to a difference between (a) spectral components of the at least one light beam reflecting off said target sample when the light beam reflecting on the sample is the “pump off” light beam, and (b) spectral components of the at least one light beam reflecting off said target sample when the light beam reflecting on the sample is the “pump on” light beam.