Cross sectional depth composition generation utilizing scanning electron microscopy

Patent metadata

Field	Value
Publication number	US-9702835-B1
Application number	US-201615059478-A
Country	US
Kind code	B1
Filing date	Mar 3, 2016
Priority date	Jan 11, 2016
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

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 to gather an energy-dispersive X-ray spectroscopy (EDS) spectrum for at least one energy level to determine element composition across an area of interest;
generating a mesh to locate positions where a depth profile will be taken;
gathering EDS spectra for a plurality of energy levels at a plurality of mesh locations;
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 and the element composition across the mesh.

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 , wherein the at least one energy level to determine element composition includes a higher energy level than any of the plurality of energy levels.

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

9. A method for generating cross-sectional profiles using a scanning electron microscope (SEM), comprising:
scanning a sample with an electron beam to gather an energy-dispersive X-ray spectroscopy (EDS) spectrum for at least one energy level;
identifying elements present in the sample using the EDS spectrum;
generating a mesh on a region of interest in a SEM image of the sample to locate positions at intersections of the mesh where a depth profile will be taken;
gathering EDS spectra for a plurality of energy levels at a plurality of mesh locations;
determining a number of layers of the sample by distinguishing differences in chemical composition between depths of the sample as beam energies are stepped through;
analyzing the chemical compositions between adjacent layers in the depth profile to determine whether a substantial difference exists; and
if a substantial difference exists, generating a depth profile for the area of interest by compiling the number of layers and the element composition across the mesh.

10. The method as recited in claim 9 , 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.

11. The method as recited in claim 9 , 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.

12. The method as recited in claim 9 , 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.

13. The method as recited in claim 12 , further comprising storing the depth profile in a data structure.

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

Assignees

• IBM

Inventors

• Campbell Eric J
• Czaplewski Sarah K

Classifications

• G01B15/04

  for measuring contours or curvatures · 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

• G01N23/2252 Primary

  Measuring emitted X-rays, e.g. electron probe microanalysis [EPMA] · CPC title

• G01N2223/418

  electron microscope · CPC title

• G01N2223/079

  incident electron beam and measuring excited X-rays · CPC title