Granted Patent B2

US 12,379,655 · App. 17/918,426 · Granted Aug 5, 2025

Inventors: Andrew Judge (Monroe, CT); Ravi Chaitanya Kalluri (Bethel, CT); Michal Emanuel Pawlowski (Norwalk, CT); James Hamilton Walsh (Newtown, CT); Justin Lloyd Kreuzer (Trumbull, CT)

Assignee: ASML Holding N.V.

G03F1/84G01N21/4795G01N21/8806G01N21/8851G01N21/94G03F7/2004G01N2021/8896

Abstract

Claims (65)

1. An inspection system comprising:

an illuminator that generates a first illumination beam at a first wavelength and a second illumination beam at a second wavelength, the first wavelength being different from the second wavelength, and irradiates an object simultaneously with the first illumination beam and the second illumination beam;

a detector that receives radiation scattered by a particle present at a surface of the object at the first wavelength and generates a detection signal; and

processing circuitry configured to:

acquire a first image based on a first intensity of the detection signal at the first wavelength;

acquire a second image based on a second intensity of a second detection signal acquired at the second wavelength;

determine a third image by comparing the first intensity and the second intensity;

analyze a photothermal modulation of Mie scattering of the detection signal at the first wavelength; and

determine a material type of the particle based on the analyzing;

wherein the first wavelength is in the visible spectrum and the second wavelength is in the infrared spectrum.

2. The inspection system of claim 1 , wherein

the processing circuitry is further configured to:

acquire sizing data corresponding to the particle from a second inspection system;

compare the acquired sizing data with a size of the particle based on the third image;

identify a trend based on the comparison; and

determine the material type of the particle based on the identified trend.

3. The inspection system of claim 2 , wherein the processing circuitry is further configured to output a corrective action warning based on the determination.

4. The inspection system of claim 1 , wherein the processing circuitry is further configured to:

analyze a photothermal modulation of Rayleigh scattering of the detection signal at the first wavelength; and

determine the material type of the particle based on the analyzing.

5. The inspection system of claim 1 , wherein the received radiation includes inelastically scattered light and the processing circuitry is further configured to:

determine the material type based on the inelastically scattered light.

6. The inspection system of claim 1 , wherein:

the detection system includes an image capture device, and

the detection signal represents image data.

7. The inspection system of claim 6 , wherein a characteristic is an edge of the particle.

8. The inspection system of claim 7 , wherein the processing circuitry is further configured to identify edges of the particle in the third image based on one or more criteria.

9. The inspection system of claim 8 , wherein the one or more criteria include a minimum intensity value, a maximum intensity value, and predicted intensity values.

10. The inspection system of claim 7 , wherein the processing circuitry is further configured to distinguish between the edge of the particle and a location of a ghost reflection based on a shift in a location in the first image and the second image.

11. The inspection system of claim 7 , wherein the detection system has a spectral range from the first wavelength to the second wavelength.

12. An inspection method comprising:

irradiating an object simultaneously with a first illumination beam at a first wavelength and a second illumination beam at a second wavelength, the first wavelength being different from the second wavelength;

receiving scattered radiation by a particle present at a surface of the object at the first wavelength;

generating a detection signal based on the received scattered radiation; analyzing the detection signal; and

determining a characteristic of the particle based on the detection signal by:

acquiring a first image based on a first intensity of the detection signal at the first wavelength;

acquiring a second image based on a second intensity of a second detection signal acquired at the second wavelength;

determining a third image by comparing the first intensity and the second intensity;

analyzing a photothermal modulation of Mie scattering of the detection signal at the first wavelength; and

determining a material type of the particle based on the analyzing;

wherein the first wavelength is in the visible spectrum and the second wavelength is in the infrared spectrum.

13. The inspection method of claim 12 , wherein:

the characteristic is a size of the particle; and

the method further comprises:

acquiring sizing data corresponding to the particle from a second inspection system, comparing the acquired sizing data with the size of the particle,

identifying a trend based on the comparison, and

determining the material type of the particle based on the identified trend.

14. The inspection method of claim 13 , further comprising:

outputting a corrective action warning based on the determination.

15. The inspection method of claim 12 , wherein:

the detection system includes an image capture device, and

the detection signal represents image data.

16. A lithography apparatus comprising:

a light source that illuminates a pattern of a patterning device;

a projector that projects an image of the pattern onto a substrate; and

a metrology system including:

an illuminator that generates a first illumination beam at a first wavelength and a second illumination beam at a second wavelength, the first wavelength being different from the second wavelength, and irradiates an object simultaneously with the first illumination beam and the second illumination beam,

a detector that receives radiation scattered by a particle present at a surface of the object at the first wavelength and generates a detection signal, and processing circuitry configured to:

acquire a first image based on a first intensity of the detection signal at the first wavelength;

acquire a second image based on a second intensity of a second detection signal acquired at the second wavelength;

determine a third image by comparing the first intensity and the second intensity;

analyze a photothermal modulation of Mie scattering of the detection signal at the first wavelength; and

determine a material type of the particle based on the analyzing;

wherein the first wavelength is in the visible spectrum and the second wavelength is in the infrared spectrum.

17. The inspection system of claim 1 , wherein, in comparing the first intensity and the second intensity, the processing circuitry is configured to perform a subtraction between the first image at the first wavelength and the second image at the second wavelength.

Assignments (2)

Continuity (2)

References Cited (25)