Automatic alignment for high throughput electron channeling contrast imaging

• US 9,859,091 B1
• Filed: 06/20/2016
• Issued: 01/02/2018
• Est. Priority Date: 06/20/2016
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bedell, Stephen W., Mukherjee, Kunal, Ott, John A., Sadana, Devendra K., Wacaser, Brent A.
• Primary Examiner(s): LOGIE, MICHAEL J
• Application Number:
  US15/187,476
• Publication Number:
  US 20170365441A1
• Time in Patent Office: 561 Days
• Field of Search: None
• CPC Class Codes: G01N 2223/321 manipulator for positioning a part
• 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 23/203 Measuring back scattering
• CPC Class Codes: G01N 23/207 Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions
• CPC Class Codes: H01J 2237/1506 Tilting or rocking beam around an axis substantially at an angle to optical axis
• CPC Class Codes: H01J 2237/2614 Holography or phase contrast, phase related imaging in general, e.g. phase plates
• CPC Class Codes: H01J 2237/2826 Calibration
• CPC Class Codes: H01J 37/1478 Beam tilting means, i.e. for stereoscopy or for beam channelling
• CPC Class Codes: H01J 37/26 Electron or ion microscopes; Electron or ion diffraction tubes
• CPC Class Codes: H01J 37/295 Electron or ion diffraction tubes

Abstract

An automatic method is provided to align a semiconductor crystalline substrate for electron channeling contrast imaging (ECCI) in regions where an electron channeling pattern cannot be reliably obtained but crystalline defects need to be imaged. The automatic semiconductor crystalline substrate alignment method is more reproducible and faster than the current operator intensive process for ECCI alignment routines. Also, the automatic semiconductor crystalline substrate alignment method increases the throughput of ECCI.

Claims

1. A method for automatic alignment that increases the throughput of electron channeling contrast imaging (ECCI), said method comprising:

providing a substrate intentionally containing a plurality of spaced apart imageable ready regions capable of generating an electron channeling pattern or electron backscatter diffraction pattern surrounded by at least one device area containing a crystalline material that has a crystallographic orientation that is aligned to the material of each of said imageable ready regions;

obtaining an image of the electron channeling pattern and/or electron backscatter diffraction pattern of each imageable ready region;

calculating, using a first algorithm, an optimum channeling angle at each imageable ready region; and

interpolating, using a second algorithm, said optimum channeling angle between and around each imageable ready region to compute the optimum channeling angle for the crystalline material present in the at least one device area.

2. The method of claim 1, wherein each imageable ready region for has at least one dimension that is longer than 1 nm for electron backscatter diffraction (EBSD).

3. The method of claim 1, wherein each imageable ready region has at least one dimension that is longer than 0.1 mm for ECP.

4. The method of claim 1, wherein each imageable ready region is entirely composed of a crystalline material.

5. The method of claim 1, wherein each imageable ready region is composed of a crystalline material with an amorphous material present on an upper surface thereof.

6. The method of claim 5, wherein said an amorphous material present on said upper surface of each imageable ready region has a thickness less than that necessary to obscure an electron channeling pattern.

7. The method of claim 1, wherein each imageable ready region comprises at least one patterned crystalline material structure.

8. The method of claim 7, wherein a region between said at least one patterned crystalline material structure can contain an amorphous material.

9. The method of claim 8, wherein said amorphous material formed between said at least one patterned crystalline material structure covers no more than the area than that necessary to obtain an electron channeling pattern.

10. The method of claim 1, wherein said obtaining said image of each imageable ready region comprises collecting an electron channeling pattern (ECP).

11. The method of claim 1, wherein said obtaining said image of each imageable ready region comprises collecting an electron backscatter diffraction (EBSD) pattern.

12. The method of claim 1, wherein said calculating, using said first algorithm, comprises:

identifying straight channeling lines; and

comparing said straight channeling lines to a crystallographic database to find one or more solutions for plane indices.

13. The method of claim 1, wherein said calculating, using said first algorithm, comprises:

identifying Kikuchi bands; and

comparing said Kikuchi bands to a crystallographic database to find one or more solutions for plane indices.

14. The method of claim 1, wherein said calculating, using said first algorithm, comprises:

acquiring an image of said electron channel patterns at each imageable ready region at a series of different substrate-beam angles; and

comparing said images to a reference image of an aligned electron channeling pattern.

15. The method of claim 14, wherein said substrate-beam angle is changed using tilt and rotation of the substrate such that the final angular error between the said pattern and the reference image is less than 0.1 degrees.

16. The method of claim 14, wherein said comparing comprising an imaging matching technique.

17. The method of claim 1, wherein said calculating, using said first algorithm, comprises:

acquiring an image of said EBSD pattern at each imageable ready region at a series of different substrate-beam angles; and

comparing said images to a reference image of an aligned EBSD pattern.

18. The method of claim 17, wherein said substrate-beam angle is changed using tilt and rotation of the substrate such that the final angular error between the said pattern and the reference image is less than 0.1 degrees.

19. The method of claim 17, wherein said comparing comprising an imaging matching technique.

20. The method of claim 1, wherein said second algorithm comprises a nearest neighbor technique, a linear technique, a polynomial technique, a spline technique or any combination thereof.