Methods for measuring a thickness of an object

Patent metadata

Field	Value
Publication number	US-9360308-B2
Application number	US-201414248673-A
Country	US
Kind code	B2
Filing date	Apr 9, 2014
Priority date	Jul 3, 2013
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

A method for analyzing an object includes measuring a first reflectivity of light from a surface and measuring a second reflectivity of light from the object, after the object is formed on the surface. A variation between the first and second reflectivities is calculated, and the variation is transformed by a predetermined transform. A thickness of the object is determined based on the transformed variation.

First claim

What is claimed is:

1. A method for analyzing an object, the method comprising:
measuring a first X-ray reflectivity from a substrate before formation of the object, measuring the first X-ray reflectivity including measuring a first X-ray reflectivity spectrum;
forming the object on the substrate;
measuring a second X-ray reflectivity from the substrate after the formation of the object, measuring the second X-ray reflectivity includes measuring a second X-ray reflectivity spectrum;
generating a delta spectrum between the first and second X-ray reflectivity spectrums, the delta spectrum corresponding to a variation between the first and second X-ray reflectivities;
transforming the variation using a fast-Fourier transform; and
determining a thickness of the object based on the transformed variation.

2. The method as claimed in claim 1 , further comprising:
irradiating an X-ray for measuring each of the first and second X-ray reflectivities at an angle of about 5 degrees or less with respect to a surface of the substrate.

3. The method as claimed in claim 1 , wherein generating the delta spectrum includes subtracting a raw first X-ray reflectivity spectrum from a raw second X-ray reflectivity spectrum.

4. The method as claimed in claim 1 , wherein the object is a layer or a pattern.

5. The method as claimed in claim 4 , wherein the layer or pattern is included in a semiconductor device.

6. The method as claimed in claim 1 , further comprising:
numerically expressing a full width at half maximum (FWMH) of a peak of a result obtained by fast-Fourier transforming the variation.

7. A method for analyzing an object, the method comprising:
measuring a first X-ray reflectivity from a substrate before formation of the object;
forming the object on the substrate;
measuring a second X-ray reflectivity from the substrate after the formation of the object;
calculating a variation between the first and second X-ray reflectivities;
transforming the calculated variation using a fast-Fourier transform;
numerically expressing a signal to noise ratio (S/N ratio) of a result obtained by fast-Fourier transforming the calculated variation; and
determining a thickness of the object based on the S/N ratio of the result obtained by fast-Fourier transforming the calculated variation.

8. A method for analyzing an object, the method comprising:
measuring a first reflectivity of light from a surface;
measuring a second reflectivity of light from the object, after the object is formed on the surface;
calculating a variation between the first and second reflectivities;
transforming the variation using a predetermined transform; and
determining a thickness of the object based on the transformed variation, wherein the method further includes numerically expressing a full width at half maximum (FWMH) of a peak of a result obtained by the predetermined transform.

9. The method as claimed in claim 8 , wherein the light is in an X-ray spectrum.

10. The method as claimed in claim 8 , wherein the predetermined transform is a fast-Fourier transform.

11. The method as claimed in claim 8 , further comprising:
irradiating light on the surface at a first angle; and
irradiating light on the object at a second angle.

12. The method as claimed in claim 11 , wherein the first angle is substantially equal to the second angle.

13. The method as claimed in claim 11 , wherein the first and second angles are in a range of about 5 degrees or less.

14. The method as claimed in claim 8 , wherein:
measuring the first reflectivity includes measuring a first reflectivity spectrum; and
measuring the second reflectivity includes measuring a second reflectivity spectrum.

15. The method as claimed in claim 14 , wherein calculating the variation includes subtracting a raw first reflectivity spectrum from a raw second reflectivity spectrum.

16. The method as claimed in claim 8 , wherein:
the surface is a surface of a semiconductor substrate; and
the object is a formation on the surface of the semiconductor substrate.

17. The method as claimed in claim 8 , further comprising:
numerically expressing a signal to noise ratio (S/N ratio) of a result obtained by the predetermined transform.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Hwang Byung Hyun
• Kim Kwang-Hoon
• Son Woongkyu
• Song Chulgi
• Leem Choonshik

Classifications

• H10P74/00

  Testing or measuring during manufacture or treatment of wafers, substrates or devices · CPC title

• G01N23/20

  by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials · CPC title

• G01B15/02 Primary

  for measuring thickness · CPC title