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High-temperature residual stresses in thin films characterized by x-ray diffraction substrate curvature method
J Keckes1, E Eiper, K J Martinschitz
1Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Department of Materials Physics, University of Leoben, Jahnstrasse 12, A-8700 Leoben, Austria. keckes@unileoben.ac.at
The Review of Scientific Instruments
|April 7, 2007
Summary
A novel X-ray technique measures temperature-dependent stress in thin films by analyzing substrate curvature. This method accurately characterizes stress in titanium nitride (TiN) and aluminum (Al) films, validating its practical application.
Area of Science:
- Materials Science
- Solid State Physics
- X-ray Diffraction
Background:
- Macroscopic stresses in thin films significantly impact device performance and reliability.
- Accurate characterization of temperature-dependent stress is crucial for optimizing thin film applications.
- Existing techniques may have limitations in determining stress evolution with temperature.
Purpose of the Study:
- Introduce and validate a new X-ray diffraction (XRD) technique for measuring temperature dependencies of macroscopic stresses in thin films.
- Demonstrate the technique's applicability on polycrystalline TiN and Al thin films on Si(100) substrates.
- Assess the accuracy and practical considerations of the developed method.
Main Methods:
- Utilized a novel heating chamber integrated with a commercial X-ray diffractometer for thermal cycling (25-400°C).
- Employed substrate curvature characterization via rocking curve measurements of Si 400 reflections.
- Calculated thin film stresses using the established Stoney's formula.
Main Results:
- Successfully determined the temperature dependencies of macroscopic stresses in TiN and Al thin films.
- The stress magnitudes obtained using this technique showed good agreement with results from other established methods.
- Demonstrated the feasibility of in-situ stress measurement during thermal cycling.
Conclusions:
- The developed X-ray technique provides a reliable method for characterizing temperature-dependent stress in thin films.
- Accurate sample mounting and precise temperature control are critical for the successful application of this technique.
- This method offers a valuable tool for materials research and development involving thin films.
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