Method and system for optical characterization of patterned samples

Patent metadata

Field	Value
Publication number	US-10876959-B2
Application number	US-201816042448-A
Country	US
Kind code	B2
Filing date	Jul 23, 2018
Priority date	Apr 30, 2014
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A method and system are presented for use in measuring on patterned samples, aimed at determining asymmetry in the pattern. A set of at least first and second measurements on a patterned region of a sample is performed, where each of the measurements comprises: directing illuminating light onto the patterned region along an illumination channel and collecting light reflected from the illuminated region propagating along a collection channel to be detected, such that detected light from the same patterned region has different polarization states which are different from polarization of the illuminating light, and generating a measured data piece indicative of the light detected in the measurement. Thus, at least first and second measured data pieces are generated for the at least first and second measurements on the same patterned region. The at least first and second measured data pieces are analyzed and output data is generated being indicative of a condition of asymmetry in the patterned region.

First claim

We claim:

1. A method for use in measuring on patterned samples, the method consists essentially of:
performing first and second measurements on a patterned region of a sample and generating measured data comprising first and second data pieces for said first and second measurements, respectively, performed on the same patterned region, said performing of each of the first and second measurements comprising:
directing illuminating light onto said patterned region along an illumination channel and controlling polarization state of the illuminating light, such that the illuminating light in each of the first and second measurement sessions has a predetermined polarization state different from that of the other of the first and second measurements, wherein the predetermined polarization states of illuminating light of the first and second measurement sessions are selected out of linear polarization at ±45° with respect to p linear polarization state; and
collecting light reflected from said patterned region propagating along a collection channel to be detected while affecting polarization state of the reflected light propagating along the collection channel, such that light being detected in each of the first and second measurements has a predetermined polarization state which is different from a polarization state of the illuminating light in said measurement, wherein the predetermined polarization states of the light being detected in each of the first and second measurement sessions are orthogonal to the predetermined polarization states of illuminating light of the first and second measurement sessions, each of the first and second measured data pieces thereby corresponding to the detected light corresponding to a reflection response of the patterned region to the illuminating light having different polarization state; and
analyzing the first and second measured data pieces to determine a relation between them, providing a direct measure of a condition of asymmetry of the pattern in said patterned region, and generating output data indicative of the condition of asymmetry in said patterned region.

2. A method of claim 1 , wherein the first and second measured data pieces correspond to different polarization states of the detected light in said first and second measurements respectively.

3. A method of claim 1 , wherein said first and second measurements comprise spectral measurements, the illuminating and collected light having broad spectral range, thereby highlighting sensitivity of the relation between the first and second measured data pieces to misalignment of pattern features.

Assignees

• Nova Measuring Instr Ltd

Inventors

• Shafir Dror
• Barak Gilad
• Wolfling Shay
• Yachini Michal Haim
• Sendelbach Matthew
• Bozdog Cornel

Classifications

• G01N2021/8848

  Polarisation of light · CPC title

• G01N21/956 Primary

  Inspecting patterns on the surface of objects {(contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} · CPC title

• G01N21/9501

  Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20) · CPC title

• G01N21/8851

  Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges (G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002) · CPC title

• G01N21/8806

  Specially adapted optical and illumination features · CPC title