Method for improving a process for a patterning process

Patent metadata

Field	Value
Publication number	US-11977336-B2
Application number	US-201917059771-A
Country	US
Kind code	B2
Filing date	May 14, 2019
Priority date	Jun 4, 2018
Publication date	May 7, 2024
Grant date	May 7, 2024

Abstract

A method for improving a process model for a patterning process, the method including obtaining a) a measured contour from an image capture device, and b) a simulated contour generated from a simulation of the process model. The method also includes aligning the measured contour with the simulated contour by determining an offset between the measured contour and the simulated contour. The process model is calibrated to reduce a difference, computed based on the determined offset, between the simulated contour and the measured contour.

First claim

The invention claimed is:

1. A method for improving a process model for a patterning process, the method comprising:
obtaining a) a measured contour from an image capture device, and b) a simulated contour generated, based on a design pattern, from a simulation of the process model;
aligning the measured contour with the simulated contour by determining an offset between the measured contour and the simulated contour, wherein the offset is determined based on distances between measurement coordinates substantially defining a portion of the measured contour and the simulated contour, the distances being in directions perpendicular to the measured contour at the measurement coordinates; and
calibrating the process model to reduce a difference, computed based on the determined offset, between the simulated contour and the measured contour.

2. The method of claim 1 , further comprising generating an edge placement (EP) coordinate on the measured contour, and wherein the offset is further determined based on the EP coordinate.

3. The method of claim 2 , wherein the EP coordinate is generated by interpolating between two or more measurement coordinates, and/or wherein the EP coordinate is generated by extrapolating from two or more measurement coordinates.

4. The method of claim 1 , wherein the calibrating further comprises modifying a feature of the process model to reduce the difference, the modifying causing a change to a shape of the simulated contour.

5. The method of claim 1 , wherein the measured contour is identified based on a change in intensity of pixels in a measured image from a plurality of measured images.

6. The method of claim 5 , wherein the measured contour is identified based on the change exceeding a greyscale threshold.

7. The method of claim 5 , wherein the image capture device is an electron beam inspection system.

8. The method of claim 1 , further comprising:
obtaining the simulated contour from Graphic Database Systems (GDS) polygons; and
converting edge placement coordinates or measurement coordinates comprising the measured contour into GDS coordinates.

9. The method of claim 1 , further comprising obtaining the simulated contour based on a simulation of an optical proximity correction (OPC) model, wherein the OPC model is a preliminary model that includes an optical model and does not include a resist model.

10. The method of claim 1 , further comprising:
obtaining an initial simulated contour with a preliminary model that includes an optical model and a resist model; and
modifying features of the resist model to reduce a difference between the initial simulated contour and the measured contour.

11. The method of claim 1 , wherein the image capture device is a scanning electron microscope.

12. A computer program product comprising a non-transitory computer readable medium having instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to at least:
obtain a) a measured contour from an image capture device, and b) a simulated contour generated, based on a design pattern, from a simulation of a process model;
align the measured contour with the simulated contour by determining an offset between the measured contour and the simulated contour, wherein the offset is determined based on distances between measurement coordinates substantially defining a portion of the measured contour and the simulated contour, the distances being in directions perpendicular to the measured contour at the measurement coordinates; and
calibrate the process model for a patterning process to reduce a difference, computed based on the determined offset, between the simulated contour and the measured contour.

13. The computer program product of claim 12 , wherein the instructions are further configured to cause the computer system to generate an edge placement (EP) coordinate on the measured contour, and wherein the offset is further determined based on the EP coordinate.

14. The computer program product of claim 13 , wherein the EP coordinate is generated by interpolating between two or more measurement coordinates, and/or wherein the EP coordinate is generated by extrapolating from two or more measurement coordinates.

15. The computer program product of claim 12 , wherein the instructions configured to cause the computer system to calibrate the process model are further configured to cause the computer system to modify a feature of the process model to reduce the difference, the modification causing a change to a shape of the simulated contour.

16. The computer program product of claim 12 , wherein the measured contour is identified based on a change in intensity of pixels in a measured image from a plurality of measured images.

17. A computer program product comprising a non-transitory computer readable medium having instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to at least:
obtain a combined image determined from a plurality of images obtained from multiple instances of a pattern measured from at least two different dies on a substrate using an image capture device, wherein at least one image of the plurality of images is obtained using a different measurement setting of the image capture device than at least one other image of the plurality of images and the different measurement setting is a different relative scanning direction between the image capture device and the applicable measured instance of the pattern;
extract a common area from the combined image;
obtain a) a contour from the common area, and b) a simulated contour generated from a simulation of a process model;
align the contour from the common area with the simulated contour by determination of an offset between the contour from the common area and the simulated contour; and
calibrate the process model for a patterning process to reduce a difference, computed based on the determined offset, between the simulated contour and the contour from the common area.

18. The computer program product of claim 17 , wherein the instructions are further configured to cause the computer system to generate an edge placement (EP) coordinate on the contour from the common area, wherein the EP coordinate is generated by interpolating between two or more measurement coordinates and/or generated by extrapolating from two or more measurement coordinates, and wherein the offset is further determined based on the EP coordinate.

19. The computer program product of claim 17 , wherein the instructions are further configured to cause the computer system to:
obtain the simulated contour from Graphic Database Systems (GDS) polygons; and
convert edge placement coordinates or measurement coordinates for the contour from the common area into GDS coordinates.

20. The computer program product of claim 17 , wherein the instructions are further configured to cause the computer system to:
obtain an initial simulated contour with a preliminary model that includes an optical model and a resist model; and
modify features of the resist model to reduce a difference between the initial simulated contour and the contour from the common area.

21. A computer program product comprising a non-transitory computer readable medium having instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to at least:
obtain a) a contour from a combined image determined from a plurality of image

Assignees

• Asml Netherlands Bv

Inventors

• Wang Jen-Shiang
• Zhao Qian
• Guo Yunbo
• Lu Yen-Wen
• Feng Mu
• Zhang Qiang

Classifications

• G03F7/70683

  Mark designs · CPC title

• G03F7/7065

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

• G03F7/70441 Primary

  Optical proximity correction [OPC] · CPC title

• G03F7/705 Primary

  Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions · CPC title

• G03F7/70625 Primary

  Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness · CPC title