**9. Acknowledgment**

452 Microelectromechanical Systems and Devices

Fig. 13. *In situ* TEM test results for Al thin film specimens. Microstructural deformations

In this chapter, the major research activities that used a tensile testing method to study the mechanical behavior of thin film materials were reviewed. For this purpose, most of the research groups designed and used their custom made test setups. A historical overview of the development of these test devices is presented. Early research in this filed started in early 90's and has continuously been pursued since then. Tensile testing research is categorized into four major steps, namely sample preparation, gripping, load actuation and measurement, and strain measurement. Each research group has mainly tackled one of these challenges and tried to implement innovative designs to address these requirements. Each one of these steps is discussed in detail in their designated sections 5- 7. Overall, among all the sample preparation techniques reviewed here, the window frame approach and polymeric sacrificial layer seems to be the most reliable fabrication processes. In terms of gripping, depending on the sample geometry, fabrication technique, and loading requirements, any of the methods presented by Tajik, 2008, Cornella, 1999, or Chasiotis & Knauss, 2002 can be utilized. A combination of window frame specimen and rough macro-gripping seems to be basis of future tensile testing techniques. Piezo actuators can be utilized as the loading actuator. They can provide enough resolution and their maximum load is within the range that is required for tensile loading of thin film specimens. Also, they can provide static and dynamic loads which can be used to test specimens under tensile, fatigue, creep, and relaxation experiments. Strain measurement still seems to be the most challenging part of the tensile testing. Different methods have been traditionally used in these experiments; however, depending on the type of application, each method has its own advantages and disadvantage. Methods based on

corresponding to the tensile test is also presented. (Haque & Saif, 2004)

**8. Conclusion** 

The financial support from the Natural Sciences and Engineering Council of Canada (NSERC) is appreciated. Center for Integrated RF Engineering (CIRFE) and WatLabs of the University of Waterloo, Nanofabrication Laboratory of the University of Western Ontario and the Canadian Centre for Electron Microscopy in McMaster University are acknowledged for providing research facilities. A great portion of this research is conducted in Laboratory for the Mechanical Properties of Thin Film Materials at the University of Waterloo.
