Method and apparatus for determining the property of a structure, device manufacturing method

Patent metadata

Field	Value
Publication number	US-10133192-B2
Application number	US-201715494056-A
Country	US
Kind code	B2
Filing date	Apr 21, 2017
Priority date	Apr 29, 2016
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A structure of interest (T) is irradiated with radiation for example in the x-ray or EUV waveband, and scattered radiation is detected by a detector ( 19, 274, 908, 1012 ). A processor (PU) calculates a property such as linewidth (CD) or overlay (OV), for example by simulating (S 16 ) interaction of radiation with a structure and comparing (S 17 ) the simulated interaction with the detected radiation. The method is modified (S 14 a , S 15 a , S 19 a ) to take account of changes in the structure which are caused by the inspection radiation. These changes may be for example shrinkage of the material, or changes in its optical characteristics. The changes may be caused by inspection radiation in the current observation or in a previous observation.

First claim

The invention claimed is:

1. A method comprising:
defining one or more variable parameters to represent a structure, the variable parameters including at least one parameter of interest;
receiving observation data obtained by exposing the structure one or more times with inspection radiation and observing the inspection radiation after interaction with the structure; and
based on the observation data, determining a value for the parameter of interest as a property of the structure,
wherein the determination of the parameter of interest is performed taking into account changes in the structure caused by the inspection radiation during an exposure period.

2. The method of claim 1 , wherein the variable parameters include one or more time-related parameters representing the changes in the structure caused by the inspection radiation during the exposure period.

3. The method of claim 2 , wherein the determining further includes determining a value for one or more of the time-related parameters.

4. The method of claim 2 , wherein at least one of the time-related parameters represents a dimensional change caused by the inspection radiation in a part of the structure.

5. The method of claim 2 , wherein at least one of the time-related parameters represents a change of an optical property caused by the inspection radiation in a part of the structure.

6. The method of claim 1 , wherein the determining takes account of intensity of the inspection radiation in combination with duration of the exposure period.

7. The method of claim 1 , wherein the observation data represents interaction of the inspection radiation with the structure accumulated over the exposure period.

8. The method of claim 1 , wherein the observation data represents interaction of the inspection radiation with the structure separately for a plurality of sub-periods of an exposure period.

9. The method of claim 1 , wherein the determination of the parameter of interest is performed taking into account changes in the structure caused by the inspection radiation during an exposure period related to a previous observation of the same structure.

10. The method of claim 1 , further comprising using a lithography device to form the structure alongside or as part of a semiconductor device.

11. The method of claim 1 , wherein the parameter of interest is determined at least partly using machine learning, based on real and/or simulated observation data obtained from different structures.

12. A method of claim 1 , wherein the determining comprises:
simulating interaction of inspection radiation with the structure with a given set of values for the variable parameters; and
comparing the interaction simulated by the simulating with the observation data;
varying one or more parameters of the structure based on the result of the comparison;
repeating the simulating using the varied parameters; and
after a number of iterations of the simulating, comparing, varying, and repeating, reporting a value for the parameter of interest.

13. A processing apparatus comprising:
storage configured to store one or more variable parameters to represent a structure, the variable parameters including at least one parameter of interest;
storage configured to receive observation data obtained by exposing the structure one or more times with inspection radiation and observing the inspection radiation after interaction with the structure; and
a processor configured to use the observation data to determine a value for the parameter of interest as a property of the structure, taking into account changes in the structure caused by the inspection radiation during an exposure period.

14. The processing apparatus of claim 13 , wherein the processing apparatus is configured to receive and use observation data representing interaction of the inspection radiation with the structure separately for a plurality of sub-periods of an exposure period.

15. The processing apparatus of claim 13 , wherein the processor is configured to take into account changes in the structure caused by the inspection radiation during an exposure period related to a previous observation of the same structure.

16. A metrology apparatus comprising:
an illumination system for generating a beam of inspection radiation;
a substrate support operable with the illumination system for irradiating a structure formed on the substrate with the inspection radiation;
a detection system for detecting the inspection radiation after interaction with the structure; and
a processing apparatus comprising:
storage configured to store one or more variable parameters to represent a structure, the variable parameters including at least one parameter of interest;
storage configured to receive observation data obtained by exposing the structure one or more times with inspection radiation and observing the inspection radiation after interaction with the structure; and
a processor configured to use the observation data to determine a value for the parameter of interest as a property of the structure, taking into account changes in the structure caused by the inspection radiation during an exposure period,

wherein the processing apparatus is configured to determine a property of the structure based on the detected radiation and taking into account changes in the structure caused by the inspection radiation during an exposure period.

17. A device manufacturing method comprising:
transferring a pattern from a patterning device onto a substrate using a lithographic process, the pattern defining at least one structure;
measuring one or more properties of the structure to determine a value for one or more parameters of the lithographic process; and
applying a correction in subsequent operations of the lithographic process in accordance with the measured property,
wherein the measuring the property of the structure includes determining a property by a method comprising:
defining one or more variable parameters to represent a structure, the variable parameters including at least one parameter of interest;
receiving observation data obtained by exposing the structure one or more times with inspection radiation and observing the inspection radiation after interaction with the structure; and
based on the observation data, determining a value for the parameter of interest as a property of the structure,
wherein the determination of the parameter of interest is performed taking into account changes in the structure caused by the inspection radiation during an exposure period.

18. A lithographic system comprising:
an illuminator configured to produce a beam of radiation;
a pattering device configured to impart a pattern on the beam of radiation;
a projection system configured to project the patterned beam onto a substrate; and
a metrology apparatus comprising:
an illumination system for generating a beam of inspection radiation;
a substrate support operable with the illumination system for irradiating a structure formed on the substrate with the inspection radiation;
a detection system for detecting the inspection radiation after interaction with the structure; and
a processing apparatus comprising:
storage configured to store one or more variable parameters to represent a structure, the variable parameters including at least one parameter of interest;
storage configured to receive observation data obtained by exposing the structure one or more times with inspection radiation and observing the inspection radiation after interaction with the structure; and
a pro

Assignees

• Asml Netherlands Bv

Inventors

• Tinnemans Patricius Aloysius Jacobus
• Mathijssen Simon Gijsbert Josephus
• Roobol Sander Bas
• Lin Nan

Classifications

• H10P74/203

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

• G01N21/95607

  using a comparative method · CPC title

• G03F7/7065

  Defects, e.g. optical inspection of patterned layer for defects · CPC title

• G01N2021/4704

  Angular selective · CPC title

• G03F7/70616 Primary

  Monitoring the printed patterns · CPC title