Cross sectional depth composition generation utilizing scanning electron microscopy

Patent metadata

Field	Value
Publication number	US-9928991-B2
Application number	US-201715581164-A
Country	US
Kind code	B2
Filing date	Apr 28, 2017
Priority date	Jan 11, 2016
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

A method for generating cross-sectional profiles using a scanning electron microscope (SEM) includes scanning a sample with an electron beam to gather an energy-dispersive X-ray spectroscopy (EDS) spectrum for an energy level to determine element composition across an area of interest. A mesh is generated to locate positions where a depth profile will be taken. EDS spectra are gathered for energy levels at mesh locations. A number of layers of the sample are determined by distinguishing differences in chemical composition between depths as beam energies are stepped through. A depth profile is generated for the area of interest by compiling the number of layers and the element composition across the mesh.

First claim

What is claimed is:

1. A method for generating cross-sectional profiles using a scanning electron microscope (SEM), comprising:
scanning a sample with an electron beam for at least one energy level to determine element composition across an area of interest;
determining a number of layers by distinguishing differences in chemical composition between depths as beam energies are stepped through; and
generating a depth profile for the area of interest by compiling the number of layers, the depths, and the element composition across a generated mesh that locates positions on the sample.

2. The method as recited in claim 1 , wherein determining the number of layers by distinguishing differences in chemical composition between depths as beam energies are stepped through includes stepping through at least three different beam energies.

3. The method as recited in claim 1 , wherein determining the number of layers by distinguishing differences in chemical composition between depths as beam energies are stepped through includes stepping through different beam energies by incrementing or decrementing beam energy by a set step size.

4. The method as recited in claim 1 , wherein generating the depth profile includes correlating beam energy with atomic number and/or material density to determine a depth of an interface between materials of different chemical compositions.

5. The method as recited in claim 4 , further comprising storing the depth profile in a data structure.

6. The method as recited in claim 1 , wherein generating the depth profile is performed if a substantial difference in chemical composition is determined between adjacent layers in the depth profile.

7. The method as recited in claim 1 , further comprising generating a mesh to locate positions where a depth profile will be taken.

8. The method as recited in claim 7 , further comprising gathering energy-dispersive X-ray spectroscopy (EDS) spectra for a plurality of energy levels at a plurality of mesh locations.

9. The method as recited in claim 8 , wherein the at least one energy level to determine element composition includes a higher energy level than any of the plurality of energy levels.

10. The method as recited in claim 1 , further comprising controlling a mesh size of the mesh to control a resolution of the depth profile.

11. The method as recited in claim 1 , wherein scanning the sample with the electron beam includes gathering an energy-dispersive X-ray spectroscopy (EDS) spectrum.

Assignees

• IBM

Inventors

• Campbell Eric J
• Czaplewski Sarah K

Classifications

• H01J37/28 Primary

  with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} · CPC title

• G01N23/22 Primary

  by measuring secondary emission from the material · CPC title

• G01B15/00

  Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons (characterised by the use of optical techniques G01B9/00, G01B11/00) · CPC title

• H01J2237/248

  Components associated with the control of the tube · CPC title

• H01J2237/2807

  X-rays · CPC title