Measurement apparatus and a method for determining a substrate grid

Patent metadata

Field	Value
Publication number	US-11966166-B2
Application number	US-202117377648-A
Country	US
Kind code	B2
Filing date	Jul 16, 2021
Priority date	Jan 30, 2018
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

A measurement apparatus and method for determining a substrate grid describing a deformation of a substrate prior to exposure of the substrate in a lithographic apparatus configured to fabricate one or more features on the substrate. Position data for a plurality of first features and/or a plurality of second features on the substrate is obtained. Asymmetry data for at least a feature of the plurality of first features and/or the plurality of second features is obtained. The substrate grid based on the position data and the asymmetry data is determined. The substrate grid and asymmetry data are passed to the lithographic apparatus for controlling at least part of an exposure process to fabricate one or more features on the substrate.

First claim

The invention claimed is:

1. A method for determining a value for a process parameter measurement error obtained from measurement of a substrate subject to a manufacturing process and comprising a target having a process distortion, the process parameter measurement error being a result of the process distortion, the method comprising:
obtaining alignment asymmetry data describing asymmetry in one or more alignment marks used for aligning the substrate, the one or more alignment marks being separate from the target;
obtaining a model correlating alignment asymmetry data to the process parameter measurement error; and
using the alignment asymmetry data and the model to obtain the value of the process parameter measurement error.

2. The method of claim 1 , wherein the process parameter is overlay.

3. The method of claim 1 , wherein the alignment asymmetry data comprises a difference in a first measured position of the one or more alignment marks when measured using radiation with a first characteristic and a second measured position of the one or more alignment marks when measured using radiation with a second characteristic.

4. The method of claim 3 , wherein the characteristic which is varied between the first characteristic and the second characteristic is wavelength and/or polarization.

5. The method of claim 1 , wherein the model comprises a neural network.

6. The method of claim 1 , further comprising determining a correction for a measurement of the process parameter from the process parameter measurement error.

7. The method of claim 6 , wherein the measurement of the process parameter is based on a measurement of the target performed with a single illumination characteristic measurement.

8. The method of claim 1 , wherein the alignment asymmetry data is further used to determine whether the manufacturing process is within specification.

9. The method of claim 8 , further comprising determining an amendment to a metrology action for measuring the process parameter based on the determination as to whether the manufacturing process is within specification.

10. The method of claim 1 , further comprising reducing a number of acquisitions of a metrology action to measure the process parameter, wherein each acquisition is performed with a different illumination characteristic.

11. The method of claim 1 , further comprising comparing the alignment asymmetry data to an alignment asymmetry threshold and categorizing the substrate based on the comparison.

12. The method of claim 11 , wherein the categorizing the substrate comprises determining whether the substrate is within or outside of specification based on the comparison.

13. The method of claim 1 , further comprising performing a calibration stage to calibrate the model.

14. The method of claim 13 , wherein the calibration stage is performed using simulated training data comprising simulated targets and simulated alignment marks, and simulated measurement responses of the simulated targets and simulated alignment marks.

15. The method of claim 14 , wherein the calibration stage calibrates the model, such that the model can characterize the process parameter measurement error based on the alignment asymmetry data.

16. A computer program product comprising a non-transitory computer-readable medium having instructions therein, the instructions, upon execution by a computer system, configured to cause the computer system to at least:
obtain alignment asymmetry data describing asymmetry in one or more alignment marks used for aligning a substrate;
obtain a model correlating alignment asymmetry data to a process parameter measurement error obtained from measurement of the substrate subject to a manufacturing process, the substrate comprising a target having a process distortion, the one or more alignment marks being separate from the target, and the process parameter measurement error being a result of the process distortion; and
use the alignment asymmetry data and the model to obtain a value of the process parameter measurement error.

17. The computer program product of claim 16 , wherein the process parameter is overlay.

18. The computer program product of claim 16 , wherein the alignment asymmetry data comprises a difference in a first measured position of the one or more alignment marks when measured using radiation with a first characteristic and a second measured position of the one or more alignment marks when measured using radiation with a second characteristic.

19. A lithocell comprising a lithographic apparatus, a metrology apparatus, and the computer program product of claim 16 .

20. The lithocell of claim 19 , wherein:
the lithographic apparatus is configured to perform alignment measurement to obtain the alignment asymmetry data;
the metrology apparatus is configured to measure the process parameter; and
the instructions of the computer program product are further configured to cause the computer system to correct the measured process parameter using the value of the process parameter measurement error.

Assignees

• Asml Netherlands Bv

Inventors

• Bijnen Franciscus Godefridus Casper
• Hulsebos Edo Maria
• Megens Henricus Johannes Lambertus
• Socha Robert John
• Zhang Youping

Classifications

• G03F7/70425 Primary

  Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning · CPC title

• G03F7/705

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

• G03F7/70516 Primary

  Calibration of components of the microlithographic apparatus, e.g. light sources, addressable masks or detectors · CPC title

• G03F7/70633

  Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching · CPC title

• G03F7/70683

  Mark designs · CPC title