EBeam Inspection Method

• US 20160314572A1
• Filed: 11/25/2015
• Published: 10/27/2016
• Est. Priority Date: 09/25/2014
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: Hermes Microvision, Inc. (ASML Holding NV)
• Inventors: Fang, Wei
• Granted Patent: US 11,315,237 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 2223/401 image processing
• CPC Class Codes: G01N 2223/418 electron microscope
• CPC Class Codes: G01N 2223/6116 semiconductor wafer
• CPC Class Codes: G01N 2223/6466 flaws comparing to predetermined standards
• CPC Class Codes: G01N 23/2251 using incident electron beams, e.g. scanning electron microscopy [SEM]
• CPC Class Codes: G06T 2207/10061 from scanning electron microscope
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/001 using an image reference approach
• CPC Class Codes: G06T 7/30 Determination of transform parameters for the alignment of images, i.e. image registration

Abstract

An image is obtained by using a charged particle beam, and a design layout information is generated to select patterns of interest. Grey levels among patterns can be compared with each other to identify abnormal, or grey levels within one pattern can be compared to a determined threshold grey level to identify abnormal.

Claims

1. An inspection method, comprising:

scanning a sample by using a charged particle beam to obtain an image;

aligning at least one pattern on the image to a design layout information, wherein the at least one pattern is generated according to the design layout information; and

determining abnormality of the at least one pattern, by using grey levels of the at least one pattern, according to the design layout information.

2. The method according to claim 1, further comprising a step of determining a threshold grey level for the at least one pattern before the step of determining abnormality.

3. The method according to claim 2, wherein the step of determining abnormality identifies a pixel of the at least one pattern is a defect if a grey level of the pixel is different from the threshold grey level.

4. The method according to claim 1, wherein the aligning step includes a group of patterns with a similar property to the at least one pattern on the image by using the design layout information.

5. The method according to claim 4, wherein the determining step compares the grey levels of the at least one pattern to each grey levels of the group of patterns.

6. The method according to claim 5, wherein the determining step identifies the at least one pattern is a defect if the grey levels of the at least one pattern are different from the each grey levels of the group of patterns.

7. The method according to claim 6, wherein the defect is a voltage contrast defect.

8. The method according to claim 1, wherein the charged particle beam is an electron beam generated by a scanning electron microscope.

9. A method for detecting defects, comprising:

scanning a sample by using a charged particle beam to obtain an image;

aligning the image to a design layout information for generating a single pattern or a group of patterns on the image; and

determining abnormality of the single pattern according to the design layout information.

10. The method according to claim 9, further comprising a step of determining a threshold grey level for the at least one pattern before the step of determining abnormality.

11. The method according to claim 10, wherein the step of determining abnormality identifies a pixel of the at least one pattern is a defect if a grey level of the pixel is different from the threshold grey level.

12. The method according to claim 9, wherein the group of patterns has a similar property to the single pattern by using the design layout information.

13. The method according to claim 12, wherein the determining step compares grey levels of the single pattern to each grey levels of the group of patterns.

14. The method according to claim 13, wherein the determining step identifies the single pattern is a defect if the grey levels of the single pattern are different from the each grey levels of the group of patterns.

15. The method according to claim 14, wherein the defect is a voltage contrast defect.

16. The method according to claim 9, wherein the charged particle beam is an electron beam generated by a scanning electron microscope.

17. A method for inspecting a sample, comprising:

scanning the sample by using an electron beam to obtain an image;

aligning a pattern on the image to a design layout information, wherein the pattern is generated from the design layout information;

determining a threshold grey level for the pattern according to the design layout information; and

identifying whether a pixel is a defect if a scanned grey level of the pixel is different from the threshold grey level.

18. The method according to claim 17, wherein the design layout information is GDS.

19. A method for inspecting a sample, comprising:

scanning a sample by using an electron beam to obtain an image;

aligning a group of patterns on the image to a design layout information, wherein the group of patterns is generated from the design layout information and has a similar property according to the design layout information; and

comparing grey levels of the group of patterns with each other to identify abnormality.

20. The method according to claim 19, wherein the design layout information is GDS.