IMAGE PROCESSING SYSTEM AND METHOD OF PROCESSING IMAGES

• US 20170345615A1
• Filed: 05/24/2017
• Published: 11/30/2017
• Est. Priority Date: 05/26/2016
• Status: Active Grant

• Current Assignee: Nanojehm Inc.
• Original Assignee: Nanojehm Inc.
• Inventors: Zotta, Matthew Daniel, Lifshin, Eric
• Granted Patent: US 10,181,391 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 18/22 Matching criteria, e.g. proximity measures
• CPC Class Codes: G06T 2207/10061 from scanning electron microscope
• CPC Class Codes: G06T 5/00 Image enhancement or restoration
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: G06V 10/42 Global feature extraction by analysis of the whole pattern, e.g. using frequency domain transformations or autocorrelation
• CPC Class Codes: G06V 10/761 Proximity, similarity or dissimilarity measures
• CPC Class Codes: G06V 20/693 Acquisition
• CPC Class Codes: G06V 20/695 Preprocessing, e.g. image segmentation
• CPC Class Codes: H01J 2237/221 Image processing
• CPC Class Codes: H01J 2237/28 Scanning microscopes
• CPC Class Codes: H01J 2237/2826 Calibration for object processing apparatus H01J2237/30433
• CPC Class Codes: H01J 37/02 Details
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence

Abstract

The disclosure relates to systems and method for processing images. The method includes selecting a predetermined reference structure, the predetermined reference structure having a known feature size/shape. The method also includes obtaining a reference image of the predetermined reference structure, and capturing a calibration image of the predetermined reference structure using an observation device. The calibration image includes a plurality of features. Additionally, the method includes identifying at least one portion of the plurality of features of the calibration image that include a feature size/shape substantially similar to the known feature size and shape of the predetermined reference structure. Finally, the method includes combining the identified portion of the plurality of features of the calibration image to form a stacked feature image, and determining a point spread function (PSF) of the observation device by comparing the obtained reference image with the stacked feature image.

Claims

1. A method of processing images, the method comprising:

selecting a predetermined reference structure, the predetermined reference structure having a known feature size and a known feature shape;

obtaining a reference feature image of the predetermined reference structure;

capturing a calibration image of the predetermined reference structure using a charged particle beam of an observation device, the calibration image including a plurality of features of the predetermined reference structure;

identifying at least one portion of the plurality of features of the calibration image that include;

a feature size substantially similar to the known feature size of the predetermined reference structure; and

a feature shape substantially similar to the known feature shape of the predetermined reference structure;

combining the at least one identified portion of the plurality of features of the calibration image to form a stacked feature image; and

determining a point spread function (PSF) of the charged particle beam by comparing the obtained reference image of the predetermined reference structure with the stacked feature image.

2. The method of claim 1, wherein identifying the at least one portion of the plurality of features of the calibration image comprises:

analyzing each of the plurality of features of the calibration image;

determining shape characteristics for each of the plurality of features of the calibration image;

determining the feature size of each of the plurality of features of the calibration image based on the shape characteristics;

determining the feature shape for each of the plurality of features of the calibration image based on the shape characteristics;

comparing the feature size of each of the plurality of features of the calibration image to the known feature size of the predetermined reference structure to determine if the feature size of each of the plurality of features of the calibration image are substantially similar to the known feature size of the predetermined reference structure; and

comparing the feature shape of each of the plurality of features of the calibration image to the known feature shape of the predetermined reference structure to determine if the feature shape of each of the plurality of features of the calibration image are substantially similar to the known feature shape of the predetermined reference structure.

3. The method of claim 1, wherein the predetermined reference structure is selected from a group consisting of:

a chemical element, a chemical compound, printed parallel nano-lines, a plurality of printed nano-dots and etched silicon.

4. The method of claim 1, wherein combining at least the identified portion of the plurality of features of the calibration image to form the stacked feature image comprises:

isolating the at least one identified portion of the plurality of features of the calibration image that include;

a feature size substantially similar to the known feature size of the predetermined reference structure; and

a feature shape substantially similar to the known feature shape of the predetermined reference structure;

cropping each feature of the at least one identified portion of the plurality of features of the calibration image to form a plurality of individual feature images for each feature of the at least one identified portion of the plurality of features of the calibration image; and

layering each of the plurality of individual feature images to form the stacked feature image from the plurality of individual feature images, the stacked feature image depicting a single feature in the stacked feature image.

5. The method of claim 4, wherein comparing the obtained reference image of the predetermined reference structure with the stacked feature image comprises:

layering the obtained reference image of the predetermined reference structure over the depicted, single feature in the stacked feature image; and

aligning the obtained reference image of the predetermined reference structure with the depicted, single feature in the stacked feature image.

6. The method of claim 4, wherein determining the PSF of the charged particle beam comprises:

calculating a difference in feature size between the obtained reference image of the predetermined reference structure and the depicted, single feature of the stacked feature image;

storing the calculated difference in feature size between the obtained reference image of the predetermined reference structure and the depicted, single feature of the stacked feature image created by the charged particle beam;

calculating a difference in feature shape between the obtained reference image of the predetermined reference structure and the depicted, single feature of the stacked feature image; and

storing the calculated difference in feature shape between the obtained reference image of the predetermined reference structure and the depicted, single feature of the stacked feature image created by the charged particle beam.

7. The method of claim 1, further comprising:

capturing a sample image of a sample material using the charged particle beam of the observation device; and

restoring the sample image of the sample material based on the determined PSF by deconvoluting the captured sample image, the restored sample image having at least one;

a higher image resolution than the captured sample image of the sample material; and

a higher image clarity than the captured sample image of the sample material.

8. An image processing system, the system comprising:

an observation device for generating a charged particle beam; and

a computer device in communication with the observation device, the computer device for performing a method of processing images including;

selecting a predetermined reference structure, the predetermined reference structure having a known feature size and a known feature shape;

obtaining a reference image of the predetermined reference structure;

obtaining a calibration image of the predetermined reference structure captured by the charged particle beam of the observation device, the calibration image including a plurality of features of the predetermined reference structure;

identifying at least one portion of the plurality of features of the calibration image that include;

a feature size substantially similar to the known feature size of the predetermined reference structure; and

a feature shape substantially similar to the known feature shape of the predetermined reference structure;

combining the at least one identified portion of the plurality of features of the calibration image to form a stacked feature image; and

determining a point spread function (PSF) of the charged particle beam by comparing the obtained reference image of the predetermined reference structure with the stacked feature image.

9. The image processing system of claim 8, wherein the known feature shape of the predetermined reference structure is one of:

a circle,

an oval,

a triangle, or

a quadrilateral.

10. The image processing system of claim 8, wherein the known feature shape of the predetermined reference structure includes any shape having eight (8) sides or less.

11. The image processing system of claim 8, wherein the method of processing the images further comprises adjusting operational characteristics of the observation device to be identical to the operational characteristics of the observation device implemented when capturing the calibration image.

12. The image processing system of claim 11, wherein the adjusted operational characteristics of the observation device include at least one of:

a beam size of the charged particle beam,

a beam energy of the charged particle beam,

accelerating voltage of the charged particle beam,

lens settings of the observation device,

a working distance between an observation lens of the observation device and the sample,

an angular position of the charged particle beam with respect to the predetermined reference structure, or

an intensity of the charged particle beam.

13. The image processing system of claim 12, wherein in response to adjusting the operational characteristics of the observation device, the method of processing images performed by the computer device further comprises:

obtaining a distinct calibration image of the predetermined reference structure captured by the charged particle beam of the observation device, the observation device having the adjusted operational characteristics;

identifying at least a distinct portion of the plurality of features of the distinct calibration image that include;

a feature size substantially similar to the known feature size of the predetermined reference structure; and

a feature shape substantially similar to the known feature shape of the predetermined reference structure;

combining the at least one identified, distinct portion of the plurality of features of the calibration image to form a distinct stacked feature image; and

determining a distinct point spread function (PSF) of the charged particle beam by comparing the obtained reference image of the predetermined reference structure with the distinct stacked feature image.

14. A computer program product stored on a non-transitory computer readable storage medium for performing a method for processing images, the computer program product comprising program code for:

selecting a predetermined reference structure, the predetermined reference structure having a known feature size and a known feature shape;

obtaining a reference image of the predetermined reference structure;

obtaining a calibration image of the predetermined reference structure captured by a charged particle beam of an observation device, the calibration image including a plurality of features of the predetermined reference structure;

identifying at least one portion of the plurality of features of the calibration image that include;

a feature size substantially similar to the known feature size of the predetermined reference structure; and

a feature shape substantially similar to the known feature shape of the predetermined reference structure;

combining the at least one identified portion of the plurality of features of the calibration image to form a stacked feature image; and

determining a point spread function (PSF) of the charged particle beam by comparing the obtained reference image of the predetermined reference structure with the stacked feature image.

15. The computer program product of claim 14, wherein identifying at least the portion of the plurality of features of the calibration image comprises:

analyzing each of the plurality of features of the calibration image;

determining shape characteristics for each of the plurality of features of the calibration image;

determining the feature size of each of the plurality of features of the calibration image based on the shape characteristics;

determining the feature shape for each of the plurality of features of the calibration image based on the shape characteristics;

comparing the feature size of each of the plurality of features of the calibration image to the known feature size of the predetermined reference structure to determine if the feature size of each of the plurality of features of the calibration image are substantially similar to the known feature size of the predetermined reference structure; and

comparing the feature shape of each of the plurality of features of the calibration image to the known feature shape of the predetermined reference structure to determine if the feature shape of each of the plurality of features of the calibration image are substantially similar to the known feature shape of the predetermined reference structure.

16. The computer program product of claim 14, wherein combining at least the identified portion of the plurality of features of the calibration image to form the stacked feature image comprises:

isolating the at least one identified portion of the plurality of features of the calibration image that include;

a feature size substantially similar to the known feature size of the predetermined reference structure; and

a feature shape substantially similar to the known feature shape of the predetermined reference structure;

cropping each feature of the at least one identified portion of the plurality of features of the calibration image to form a plurality of individual feature images for each feature of the at least one identified portion of the plurality of features of the calibration image; and

layering each of the plurality of individual feature images to form the stacked feature image from the plurality of individual feature images, the stacked feature image depicting a single feature in the stacked feature image.

17. The computer program product of claim 16, wherein the predetermine reference structure substantially reflects electrons and is positioned on a support component, and wherein the support component substantially absorbs electrons.

18. The computer program product of claim 16, wherein comparing the obtained reference image of the predetermined reference structure with the stacked feature image comprises:

layering the obtained reference image of the predetermined reference structure over the stacked feature image; and

aligning the obtained reference image of the predetermined reference structure with the depicted, single feature of the stacked feature image.

19. The computer program product of claim 18, wherein determining the PSF of the charged particle beam based on the obtained reference image of the predetermined reference structure and the stacked feature image comprises:

calculating a difference in feature size between the obtained reference image of the predetermined reference structure and the depicted, single feature of the stacked feature image;

storing the calculated difference in feature size between the obtained reference image of the predetermined reference structure and the depicted, single feature of the stacked feature image created by the charged particle beam;

calculating a difference in feature shape between the obtained reference image of the predetermined reference structure and the depicted, single feature of the stacked feature image; and

storing the calculated difference in feature shape between the obtained reference image of the predetermined reference structure and the depicted, single feature of the stacked feature image created by the charged particle beam.

20. The computer program product of claim 14, further comprising:

capturing a sample image of a sample material using the charged particle beam of the observation device; and

restoring the sample image of the sample material based on the determined PSF by deconvoluting the captured sample image, the restored sample image having a higher image resolution than the captured sample image of the sample material and higher image clarity than the captured sample image of the sample material.