Method of testing an unknown sample with an analytical tool

• US 6,519,542 B1
• Filed: 05/09/2000
• Issued: 02/11/2003
• Est. Priority Date: 05/09/2000
• Status: Expired due to Term

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Giannuzzi, Lucille A., Stevie, Frederick A., Vartuli, Cathrine
• Primary Examiner(s): Hilten, John S.
• Assistant Examiner(s): Washburn, Douglas N
• Application Number:
  US09/567,373
• Time in Patent Office: 1,008 Days
• Field of Search: 250/307, 250/573, 250/252.1, 422/102, 436/14, 438/16, 73/191, 702/32, 378/53, 364/531.02
• US Class Current: 702/85
• CPC Class Codes: G01N 2001/2893 Preparing calibration standards
• CPC Class Codes: G01N 23/2251 using incident electron beams, e.g. scanning electron microscopy [SEM]
• CPC Class Codes: H01J 49/0009 Calibration of the apparatus
• CPC Class Codes: H01J 49/0027 Methods for using particle spectrometers

Abstract

The present invention provides a method of testing an unknown sample with an analytical tool The method may include calibrating an analytical tool to a calibration standard having a known concentration of an element therein and obtained with a focused beam, thereby to achieve a calibrated analytical tool, determining an unknown concentration of the element within the unknown sample with the calibrated analytical tool, and correcting the unknown concentration with the calibration standard.

Claims

1. A method of testing an unknown sample with an analytical tool, comprising:

calibrating an analytical tool, wherein calibrating includes;

obtaining a calibration standard having a known concentration of an element therein;

obtaining a portion of the calibration standard with a focused beam, wherein the portion is representative of the known concentration; and

calibrating the analytical tool with the portion;

determining an unknown concentration of the element within the unknown sample with the calibrated analytical tool; and

correcting the unknown concentration with the calibration standard.

2. The method as recited in claim 1 wherein calibrating further includes obtaining a detection limit of the analytical tool with respect to the known concentration.

3. The method as recited in claim 1 wherein calibrating includes implanting the calibration standard with a known concentration of the element.

4. The method as recited in claim 3 wherein implanting includes implanting the known matrix with the element to achieve a concentration of about 1E21 atoms/cm³ of the element.

5. The method as recited in claim 3 wherein implanting the element includes implanting the element by ion implantation.

6. The method as recited in claim 1 wherein calibrating includes determining the known concentration using secondary ion mass spectrometry (SIMS) or rutherford backscattering spectrometry (RBS).

7. The method as recited in claim 1 wherein calibrating includes obtaining the calibration standard with a focused ion beam process.

8. The method as recited in claim 1 wherein calibrating includes obtaining the calibration standard with a subatomic particle beam or a laser beam.

9. The method as recited in claim 1 wherein calibrating an analytical tool includes calibrating an analytical tool selected from the group consisting of:

energy dispersive spectrometry (EDS),

microcalorimetry,

auger electron spectroscopy (AES), and

x-ray photoelectron spectroscopy (XPS).

10. The method as recited in claim 1 wherein calibrating includes obtaining a thin portion of the calibration standard having a thickness of between about 50 nm and about 5000 nm.

11. The method as recited in claim 10 wherein obtaining a thin portion includes obtaining a thin portion having a length of about 20000 nm and a depth of about 5000 nm.

12. The method as recited in claim 1 further comprising creating a sample holder and placing the calibration standard in the sample holder, wherein creating the sample holder includes;

providing a main body having first and second opposing major surfaces, a recess in the first major surface and a main body aperture narrower than the recess and extending from a base of the recess to the second major surface; and

constructing a plug that engages an inner wall of the recess to fix the plug with respect to the main body and fix a grid containing the sample between the base and the plug, the plug having a plug aperture extending therethrough that aligns with the main body aperture to form a path to and through the sample for a beam from a selected one of multiple analytical tools.

13. The method as recited in claim 1 further including a second analytical tool, wherein the calibration standard is used to determine a detection limit of the second analytical tool.

14. The method as recited in claim 13 wherein the first analytical tool is a secondary ion mass spectrometer and the second analytical tool is selected from the group consisting of:

energy dispersive spectrometry (EDS),

microcalorimetry,

auger electron spectroscopy (AES), and

x-ray photoelectron spectroscopy (XPS).

15. A system for testing an unknown sample with an analytical tool, comprising:

a first analytical tool capable of determining a concentration of an element located within a calibration standard;

a focused beam apparatus capable of extracting a portion from the calibration standard; and

a portion extracted from the calibration standard with the focused beam apparatus, the portion being representative of the concentration;

a second analytical tool having a detection limit with respect to the concentration; and

an unknown test sample having an unknown concentration of the element therein.

16. The system as recited in claim 15 wherein the first analytical tool is a secondary ion mass spectrometry (SIMS).

17. The system as recited in claim 15 wherein the calibration standard has a concentration of the element of about 1E21 atoms /cm³ of the element.

18. The system as recited in claim 15 wherein the focused beam apparatus is a focused ion beam apparatus.

19. The system as recited in claim 15 wherein the second analytical tool is selected from the group consisting of:

energy dispersive spectrometry (EDS),

microcalorimetry,

auger electron spectroscopy (AES), and

x-ray photoelectron spectroscopy (XPS).

20. The system as recited in claim 15 wherein the portion is a thin portion having a thickness of between about 50 nm and about 5000 nm.

21. The system as recited in claim 20 wherein the thin portion has a length of about 20000 nm and a depth of about 5000 nm.

22. The system as recited in claim 15 wherein the second analytical tool has a sample holder bay and the system further includes a sample holder configured to hold the calibration standard and to cooperatively engage the sample holder bay.

23. The system as recited in claim 22 wherein the sample holder comprises:

a main body having first and second opposing major surfaces, a recess in the first major surface and a main body aperture narrower than the recess and extending from a base of the recess to the second major surface; and

a plug that engages an inner wall of the recess to fix the plug with respect to the main body and fix a grid containing the sample between the base and the plug, the plug having a plug aperture extending therethrough that aligns with the main body aperture to form a path to and through the sample for a beam from a selected one of multiple second analytical tools.