In-situ Combined Sensing of Uniaxial Nanomechanical and Micromechanical Stress with Simultaneous Measurement of Surface Temperature Profiles by Raman Shift in Nanoscale and Microscale Structures

Patent metadata

Field	Value
Publication number	US-2016018334-A1
Application number	US-201514800088-A
Country	US
Kind code	A1
Filing date	Jul 15, 2015
Priority date	Jul 16, 2014
Publication date	Jan 21, 2016
Grant date	—

Abstract

Embodiments of the present disclosure include separating a measured Raman shift signal into mechanical and thermal components when a uniaxial compressive load is applied in situ. In some embodiments, in situ uniaxial compressive loads are applied on examined specimens from room temperature to 150° C. In alternate embodiments, Raman shift measurements are performed as a function of strain at constant temperature and/or as a function of temperature at constant strain levels. It was realized that the Raman shift measured at a given temperature under a given level of applied stress can be expressed as a summation of stress-induced Raman shift signal and temperature-induced Raman shift signal measured separately. Such a separation of Raman shift signal is utilized by various embodiments to measure localized change in thermal conductivity and/or mechanical stress of structures (e.g., semiconductor structures) under applied stress.

First claim

What is claimed is:

1 . A method for measuring mechanical properties of a microscale or nanoscale structure, comprising:
receiving energy reflected from a structure while the structure is being illuminated; and determining at least one stress property and at least one temperature property of the structure from the energy received from the structure.

2 . The method of claim 1 , comprising:
illuminating the structure with a laser.

3 . The method of claim 1 , wherein said determining at least one stress property and at least one temperature property of the structure occurs simultaneously from the energy received from the structure.

4 . The method of claim 1 , wherein said determining includes analyzing the energy received from the structure by Raman spectroscopy.

5 . The method of claim 1 , comprising:
applying stress to the structure.

6 . The method of claim 1 , wherein said determining includes:
measuring the Raman shift difference Δω m ; and calculating stress components σij.

7 . The method of claim 1 , wherein said determining includes determining the stress distribution below the surface of the structure.

8 . The method of claim 1 , wherein said determining includes determining the thermal conductivity of the structure.

9 . The method of claim 1 , comprising:
illuminating the structure with a laser; applying stress to the structure; measuring the Raman shift difference Δω m ; and calculating stress components σij; wherein said determining at least one stress property and at least one temperature property of the structure occurs simultaneously from the energy received from the structure; and wherein said determining includes determining the stress distribution below the surface of the structure and determining the thermal conductivity of the structure.

10 . An apparatus for measurement of stress and temperature of a nanoscale or microscale structure, comprising:
a receiver configured and adapted to receive energy from a nanoscale or microscale structure while the structure is being illuminated with laser energy; and a processor connected to said receiver, the processor configured and adapted to obtain information related to the received energy from the receiver, and
determine at least one stress property and at least one temperature property of the structure from the information obtained from the receiver.

11 . The apparatus of claim 10 , wherein the receiver and the processor are configured and adapted to perform Raman spectroscopy on the energy received from the structure.

12 . The apparatus of claim 10 , comprising:
a stress inducing member configured and adapted to impart stress to the structure during said receiving.

13 . The apparatus of claim 10 , comprising:
a laser connected to the receiver, the laser configured and adapted to impart laser energy to the structure.

14 . The apparatus of claim 10 , wherein the processor determines at least one stress property and at least one temperature property of the structure from the same information obtained from the receiver.

15 . The apparatus of claim 10 , comprising:
a stress inducing member configured and adapted to impart stress to the structure during said receiving; a laser connected to the receiver, the laser configured and adapted to impart laser energy to the structure; wherein the receiver and the processor are configured and adapted to perform Raman spectroscopy on the energy received from the structure; and wherein the processor determines at least one stress property and at least one temperature property of the structure from the same information obtained from the receiver.

16 . A method for measuring thermal conductivity of a microscale or nanoscale structure, comprising:
receiving energy from a structure being illuminated with energy and to which a stress load is being applied; and determining the thermal conductivity of the structure from the energy received from the structure.

17 . The method of claim 16 , comprising:
applying the stress load to the structure.

18 . The method of claim 17 , comprising:
illuminating the structure with a laser.

19 . The method of claim 18 , wherein said determining includes analyzing the energy received from the structure by Raman spectroscopy.

20 . The method of claim 19 ,
wherein said applying applies the stress load in a uniaxial direction along a load axis; wherein said illuminating and said receiving are performed on a surface, the surface defining a surface axis normal to the surface; and wherein the surface axis is perpendicular to the load axis.

Assignees

• Purdue Research Foundation

Inventors

• Tomar Vikas
• Gan Ming

Classifications

• G01N21/65 Primary

  Raman scattering · CPC title

• G01L1/24

  by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis {using infrared, visible light, ultraviolet} · CPC title

• G01K13/00

  Thermometers specially adapted for specific purposes · CPC title