Method and apparatus for image analysis

Patent metadata

Field	Value
Publication number	US-11143970-B2
Application number	US-202016943296-A
Country	US
Kind code	B2
Filing date	Jul 30, 2020
Priority date	Dec 9, 2014
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

A method and apparatus of detection, registration and quantification of an image is described. The method may include obtaining an image of a lithographically created structure, and applying a level set method to an object, representing the structure, of the image to create a mathematical representation of the structure. The method may include obtaining a first dataset representative of a reference image object of a structure at a nominal condition of a parameter, and obtaining second dataset representative of a template image object of the structure at a non-nominal condition of the parameter. The method may further include obtaining a deformation field representative of changes between the first dataset and the second dataset. The deformation field may be generated by transforming the second dataset to project the template image object onto the reference image object. A dependence relationship between the deformation field and change in the parameter may be obtained.

First claim

What is claimed is:

1. A method comprising:
evolving, by a hardware computer processor system, a curve enclosing an object subject to constraints of the object, the object, representing a lithographically created structure, of an image from a SEM or optical inspection apparatus;
terminating evolution of the curve when an area enclosed by the curve reaches to, or near, the boundary of the object; and
obtaining, by the hardware computer processor system, a numerical function upon termination of the evolution of the curve, wherein the numerical function is configured for a classification of a defect, for an estimation of a defect, for a monitoring of a process, and/or for a controlling of a process.

2. The method of claim 1 , further comprising binarizing the numerical function to obtain a dataset representing the object.

3. The method of claim 2 , wherein binarizing the numerical function comprises setting a value of the numerical function to a certain value for all spaces where the numerical function has a value greater than zero, and setting the value of the numerical function to another value for all spaces where the numerical function has a value less than zero.

4. The method of claim 1 , wherein evolving the curve comprises applying a level set method comprising minimizing an energy functional via variational calculus.

5. The method of claim 1 , further comprising using the numerical function to change a parameter of a process to create the structure and/or to evaluate an image comprising a plurality of structures to identify one or more instances of the particular structure in the image.

6. The method of claim 1 , wherein the structure comprises a circuit feature of an integrated circuit and/or the image is a scanning electron microscope image.

7. A method of manufacturing devices wherein a device pattern is applied to a series of substrates using a lithographic process, the method including evaluating, using the method of claim 1 , a lithographically created structure imaged using the lithographic process and controlling the lithographic process for one or more of the substrates in accordance with the result of the method.

8. The method of claim 7 , wherein the lithographically created structure is imaged on at least one of the substrates and controlling the lithographic process for later substrates in accordance with the result of the method.

9. A non-transitory computer program product comprising machine-readable instructions therein, the instructions, upon execution by a computer processor system, configured to cause the computer processor system to at least:
evolve a curve enclosing an object subject to constraints of the object, the object, representing a lithographically created structure, of an image from a SEM or optical inspection apparatus;
terminate evolution of the curve when an area enclosed by the curve reaches to, or near, the boundary of the object; and
obtain a numerical function upon termination of the evolution of the curve, wherein the numerical function is configured for a classification of a defect, for an estimation of a defect, for a monitoring of a process, and/or for a controlling of a process.

10. The computer program product of claim 9 , wherein the instructions are further configured to cause the computer processor system to binarize the numerical function to obtain a dataset representing the object.

11. The computer program product of claim 10 , wherein the instructions configured to cause the computer processor system to binarize the numerical function are further configured to cause the computer processor system to set a value of the numerical function to a certain value for all spaces where the numerical function has a value greater than zero, and set the value of the numerical function to another value for all spaces where the numerical function has a value less than zero.

12. The computer program product of claim 9 , wherein the instructions configured to cause the computer processor system to evolve the curve are further configured to cause the computer processor system to apply a level set method comprising minimization of an energy functional via variational calculus.

13. The computer program product of claim 9 , wherein the instructions are further configured to cause the computer processor system to use the numerical function to change a parameter of a process to create the structure and/or to evaluate an image comprising a plurality of structures to identify one or more instances of the particular structure in the image.

14. The computer program product of claim 9 , wherein the structure comprises a circuit feature of an integrated circuit and/or the image is a scanning electron microscope image.

15. A system comprising:
an inspection apparatus configured to provide an image of a lithographically created structure; and
an image analysis engine comprising the non-transitory computer program product of claim 9 .

16. The system of claim 15 , wherein the inspection apparatus is an electron beam measurement apparatus.

17. A non-transitory computer program product comprising machine-readable instructions therein, the instructions, upon execution by a computer processor system, configured to cause the computer processor system to at least:
apply a level set method to an object, representing a lithographically created structure, of an image from a SEM or optical inspection apparatus such that a curve is evolved relative to the object subject to constraints of the object; and
upon termination of evolution of the curve when an area enclosed by the curve reaches to, or near, the boundary of the object, create a mathematical representation of the structure, wherein the mathematical representation is configured for a classification of a defect, for an estimation of the defect, for a monitoring of a process, and/or for a controlling of a process.

18. The computer program product of claim 17 , wherein the application of the level set method comprises minimization of an energy functional via variational calculus.

19. The computer program product of claim 17 , wherein the instructions are further configured to cause the computer processor system to binarize the mathematical representation to obtain a dataset representing the object.

20. The computer program product of claim 17 , wherein the instructions are further configured to cause the computer processor system to use the mathematical representation to change a parameter of a process to create the structure.

21. A non-transitory computer program product comprising machine-readable instructions therein, the instructions, upon execution by a computer processor system, configured to cause the computer processor system to at least:
process a noisy SEM or optical inspection image containing an object representing a lithographically created structure, by:
evolution of a curve enclosing the object subject to constraints of the object, or
application of a level set method to the object such that a curve is evolved relative to the object subject to constraints of the object; and

obtain a high resolution mathematical representation or numerical function corresponding to the structure upon termination of evolution of the curve, wherein the mathematical representation or numerical function is configured for a classification of a defect, for an estimation of a defect, for a monitoring of a process, and/or for a controlling of a process.

22. The computer program product of claim 21 , wherein the instruct

Assignees

• Asml Netherlands Bv

Inventors

• Middlebrooks Scott Anderson
• Van Kraaij Markus Gerardus Martinus Maria
• Koopman Adrianus Cornelis Matheus
• Hunsche Stefan
• Coene Willem Marie Julia Marcel

Classifications

• G06T7/12

  Edge-based segmentation · CPC title

• G06T7/149

  involving deformable models, e.g. active contour models · CPC title

• G06T2207/30148

  Semiconductor; IC; Wafer · CPC title

• G06T2207/20161

  Level set · CPC title

• G06T2207/10061

  from scanning electron microscope · CPC title