Time-domain optical metrology and inspection of semiconductor devices

Patent metadata

Field	Value
Publication number	US-11366398-B2
Application number	US-201917254357-A
Country	US
Kind code	B2
Filing date	Jul 18, 2019
Priority date	Jul 18, 2018
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

Abstract

Semiconductor device metrology including creating a time-domain representation of wavelength-domain measurement data of light reflected by a patterned structure of a semiconductor device, selecting an earlier-in-time portion of the time-domain representation that excludes a later-in-time portion of the time-domain representation, and determining one or more measurements of one or more parameters of interest of the patterned structure by performing model-based processing using the earlier-in-time portion of the time-domain representation.

First claim

What is claimed is:

1. A method for semiconductor device metrology, the method comprising:
creating a time-domain representation of wavelength-domain measurement data of light reflected by a patterned structure of a semiconductor device;
selecting an earlier-in-time portion of the time-domain representation that excludes a later-in-time portion of the time-domain representation; and
determining one or more measurements of one or more parameters of interest of the patterned structure by performing model fitting using a predefined model of the patterned structure to determine a set of theoretical measurements of the patterned structure that would result in a theoretical time-domain representation of wavelength-domain measurement data of light expected to be reflected by the patterned structure given the set of theoretical measurements, where the theoretical time-domain representation is substantially identical, within predefined tolerances, to the earlier-in-time portion of the time-domain representation.

2. The method according to claim 1 wherein the predefined model models one or more upper layers of the patterned structure corresponding to the earlier-in-time portion of the time-domain representation.

3. The method according to claim 2 wherein the predefined model models the one or more upper layers of the patterned structure excluding all other layers of the patterned structure.

4. The method according to claim 1 wherein the wavelength-domain measurement data include spectral amplitude and spectral phase, and wherein the creating comprises creating the time-domain representation using both the spectral amplitude and the spectral phase.

5. A method for semiconductor device metrology, the method comprising:
creating a time-domain representation of wavelength-domain measurement data of light reflected by a patterned structure of a semiconductor device;
selecting an earlier-in-time portion of the time-domain representation that excludes a later-in-time portion of the time-domain representation;
transforming the selected earlier-in-time portion of the time-domain representation into time-filtered wavelength-domain measurement data; and
determining one or more measurements of one or more parameters of interest of the patterned structure by performing model fitting using a predefined model of the patterned structure to determine a set of theoretical measurements of the patterned structure that would result in a theoretical wavelength-domain measurement data of light expected to be reflected by the patterned structure given the set of theoretical measurements, where the theoretical wavelength-domain representation is substantially identical, within predefined tolerances, to the time-filtered wavelength-domain measurement data.

6. The method according to claim 5 wherein the predefined model models one or more upper layers of the patterned structure corresponding to the time-filtered wavelength-domain measurement data.

7. The method according to claim 6 wherein the predefined model models the one or more upper layers of the patterned structure excluding all other layers of the patterned structure.

8. The method according to claim 5 wherein the wavelength-domain measurement data include spectral amplitude and spectral phase, and wherein the creating comprises creating the time-domain representation using both the spectral amplitude and the spectral phase.

9. A system for semiconductor device metrology, the system comprising:
a spectrum processing unit configured to
create a time-domain representation of wavelength-domain measurement data of light reflected by a patterned structure of a semiconductor device, and
select an earlier-in-time portion of the time-domain representation that excludes a later-in-time portion of the time-domain representation; and

a metrology unit configured to determine one or more measurements of one or more parameters of interest of the patterned structure by performing model fitting using a predefined model of the patterned structure to determine a set of theoretical measurements of the patterned structure that would result in a theoretical time-domain representation of wavelength-domain measurement data of light expected to be reflected by the patterned structure given the set of theoretical measurements, where the theoretical time-domain representation is substantially identical, within predefined tolerances, to the earlier-in-time portion of the time-domain representation,
wherein the spectrum processing unit and the metrology unit are implemented in any of
a) computer hardware, and
b) computer software embodied in a non-transitory, computer-readable medium.

10. The system according to claim 9 wherein the predefined model models one or more upper layers of the patterned structure corresponding to the earlier-in-time portion of the time-domain representation.

11. The system according to claim 10 wherein the predefined model models the one or more upper layers of the patterned structure excluding all other layers of the patterned structure.

12. The system according to claim 9 wherein the wavelength-domain measurement data include spectral amplitude and spectral phase, and wherein the spectrum processing unit is configured to create the time-domain representation using both the spectral amplitude and the spectral phase.

13. A system for semiconductor device metrology, the system comprising:
a spectrum processing unit configured to
create a time-domain representation of wavelength-domain measurement data of light reflected by a patterned structure of a semiconductor device,
select an earlier-in-time portion of the time-domain representation that excludes a later-in-time portion of the time-domain representation, and
transform the selected earlier-in-time portion of the time-domain representation into time-filtered wavelength-domain measurement data; and

a metrology unit configured to determine one or more measurements of one or more parameters of interest of the patterned structure by performing model fitting using a predefined model of the patterned structure to determine a set of theoretical measurements of the patterned structure that would result in a theoretical wavelength-domain measurement data of light expected to be reflected by the patterned structure given the set of theoretical measurements, where the theoretical wavelength-domain representation is substantially identical, within predefined tolerances, to the time-filtered wavelength-domain measurement data,
wherein the spectrum processing unit and the metrology unit are implemented in any of
a) computer hardware, and
b) computer software embodied in a non-transitory, computer-readable medium.

14. The system according to claim 13 wherein the predefined model models one or more upper layers of the patterned structure corresponding to the time-filtered wavelength-domain measurement data.

15. The system according to claim 14 wherein the predefined model models the one or more upper layers of the patterned structure excluding all other layers of the patterned structure.

16. The system according to claim 13 wherein the wavelength-domain measurement data include spectral amplitude and spectral phase, and wherein the spectrum processing unit is configured to create the time-domain representation using both the spectral amplitude and the spectral phase.

Assignees

• Nova Ltd

Inventors

• Barak Gilad
• Chemama Michael
• Ferber Smadar
• Hainick Yanir
• Levant Boris
• Lindenfeld Ze'ev
• Shafir Dror
• Shirman Yuri
• Schleifer Elad

Classifications

• H10P74/23

  characterised by multiple measurements, corrections, marking or sorting processes · CPC title

• H10P74/203 Primary

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• G03F7/706849

  Irradiation branch, e.g. optical system details, illumination mode or polarisation control · CPC title

• G01B2210/56

  Measuring geometric parameters of semiconductor structures, e.g. profile, critical dimensions or trench depth · CPC title

• G01B11/0625 Primary

  with measurement of absorption or reflection · CPC title