US 12,359,968 B2
Systems and methods for optical metrology
Yonatan Oren, Kiryat Ono (IL); Eyal Hollander, Ramat Hasharon (IL); Elad Schleifer, Rehovot (IL); and Gilad Barak, Rehovot (IL)
Assigned to NOVA LTD., Rehovot (IL)
Appl. No. 18/003,801
Filed by NOVA LTD., Rehovot (IL)
PCT Filed Jul. 5, 2021, PCT No. PCT/IL2021/050824
§ 371(c)(1), (2) Date Dec. 29, 2022,
PCT Pub. No. WO2022/009197, PCT Pub. Date Jan. 13, 2022.
Claims priority of provisional application 63/048,137, filed on Jul. 5, 2020.
Prior Publication US 2023/0296436 A1, Sep. 21, 2023
Int. Cl. G01J 3/10 (2006.01); G01J 3/02 (2006.01); G01J 3/18 (2006.01); G01J 3/28 (2006.01); G01J 3/44 (2006.01)
CPC G01J 3/10 (2013.01) [G01J 3/0208 (2013.01); G01J 3/0248 (2013.01); G01J 3/0291 (2013.01); G01J 3/18 (2013.01); G01J 3/2803 (2013.01); G01J 3/44 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A metrology system for measuring characteristics of workpieces, the metrology system comprising at least:
a. an illumination subsystem comprising at least one light source;
b. a workpiece handling subsystem configured at least for holding each tested workpiece to be measured at a specific required measuring-position;
c. an optical subsystem configured and arranged to form at least one multi-spot-array, from light emanating from the at least one light source, over a test area of the tested workpiece;
d. at least one spectrometry device having at least one aperture, positioned at a specific relative-position in respect to the test area of the tested workpiece, wherein the optical subsystem is further arranged and configured to direct light emanating from the multi-spot-array, onto the at least one aperture of the spectrometry device, for detecting spectral characteristics of one or more spots of the multi-spot-array;
e. at least one processing and control unit (PCU), configured to receive spectral output data from the at least one spectrometry device to determine spectral characteristics of the one or more spots of the multi-spot-array, and determine one or more properties of the tested area of the tested workpiece, based on determined spectral characteristics of the one or more spots, wherein the distribution of energy density or flux of the at least one multi-spot-array over the test area of the tested workpiece is such that it prevents affecting the workpiece during its testing;
wherein the optical subsystem comprises:
at least one beam splitter for dividing light emanating from the at least one light source and reflecting light arriving from the tested workpiece;
a collimator configured to collimate light beam emanating from the at least one light source;
at least one lenslet array comprising an array of focusing micro-lenses located between the collimator and the tested workpiece, wherein the at least one lenslet array is positioned and configured to have collimated light manipulated to form the at least one multi-spot-array over the tested workpiece test area, and a focusing lens located between the at least one lenslet array and the tested workpiece;
wherein the at least one lenslet array comprises two lenslet arrays located parallelly to one another, wherein one of the two lenslet arrays is located at a pupil plane of the micro-lenses of the other lenslet array.