Granted Patent B2

US 12,444,628 · App. 17/849,554 · Granted Oct 14, 2025

Inventors: Stefan Eyring (Weilburg, DE); Zhijin Chen (Milpitas, CA); Frank Laske (Weilmunster, DE)

Assignee: KLA CORPORATION

H01L21/67276G06T7/0004G06T2207/30148

Abstract

Claims (39)

1. A system comprising:

a particle beam source that generates a particle beam;

a stage configured to hold a wafer in a path of the particle beam;

a detector that receives particles from the wafer; and

a processor in electronic communication with the detector, wherein the processor is configured to:

receive an image of a structure on the wafer;

determine a contour of a structure in the image of the wafer;

determine a simulated image of the structure from a design of the wafer, wherein the simulated image includes at least one error that accounts for noise sources and imaging properties of the system;

determine a contour of the structure in the simulated image;

compare the contour of the structure in the image and the contour of the structure in the simulated image;

determine a difference in polygons between the contour of the structure in the image and the contour of the structure in the simulated image;

determine a modified design of the structure based on the difference in polygons;

determine a second simulated image of the structure from the modified design, wherein the second simulated image accounts for noise sources and imaging properties of the system;

determine a contour of the structure in the second simulated image; and

compare the contour of the structure in the image and the contour of the structure in the second simulated image.

2. The system of claim 1 , wherein the system is a scanning electron microscope.

3. The system of claim 1 , wherein the particles are electrons and the particle beam is an electron beam.

4. The system of claim 1 , wherein the processor is further configured to report the difference in polygons when the difference in polygons is below a threshold.

5. The system of claim 1 , wherein comparing the contour includes dividing each segment into blocks with a fixed size and comparing the blocks of the structure in the image and the simulated image.

6. The system of claim 1 , wherein comparing the contour includes matching one or more vertices along the contour in the image and the contour in the simulated image.

7. A method comprising:

directing a particle beam at a wafer using a wafer metrology tool;

generating, using a processor, an image of the wafer based on particles reflected from the wafer;

determining, using the processor, a contour of a structure in the image of the wafer;

determining, using the processor, a simulated image of the structure from a design of the wafer, wherein the simulated image includes at least one error that accounts for noise sources and imaging properties of the wafer metrology tool;

determining, using the processor, a contour of the structure in the simulated image; and

comparing, using the processor, the contour of the structure in the image and the contour of the structure in the simulated image;

determining a difference in polygons between the contour of the structure in the image and the contour of the structure in the simulated image using the processor;

determining a modified design of the structure based on the difference in polygons using the processor;

determining, using the processor, a second simulated image of the structure from the modified design, wherein the second simulated image accounts for noise sources and imaging properties of the wafer metrology tool;

determining, using the processor, a contour of the structure in the second simulated image; and

comparing, using the processor, the contour of the structure in the image and the contour of the structure in the second simulated image.

8. The method of claim 7 , wherein the wafer metrology tool is a scanning electron microscope.

9. The method of claim 7 , wherein the particle beam is an electron beam and the particles are electrons.

10. The method of claim 7 , further comprising reporting the difference in polygons when the difference in polygons is below a threshold.

11. A non-transitory computer readable medium storing a program configured to instruct a processor to execute the method of claim 7 .

12. The method of claim 7 , wherein comparing the contour includes dividing each segment into blocks with a fixed size and comparing the blocks of the structure in the image and the simulated image.

13. The method of claim 7 , wherein comparing the contour includes matching one or more vertices along the contour in the image and the contour in the simulated image.

14. The method of claim 7 , wherein the particle beam has a high beam current configured to measure buried layers of the wafer.

Assignments (1)

Continuity (1)

References Cited (15)