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Development of Real-time Stress/strain Measurement Techniques

More Experimental Micro and Nanomechanics Research

Development of advanced warpage measurement techniques

Development of real-time stress/strain measurement techniques

Development of nano-scale deformation measurement techniques


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The industry has been employing the Accelerated Thermal Cycling (ATC) test to reduce the time required for reliability assessment, where the devices are tested in much more severe environments.  The results are used to predict the number of cycles to failure at the actual operating conditions by employing an acceleration parameter.  In the ATC test, the whole assembly is subjected to heating and cooling cycles in an environmental chamber.

When deformation measurements are required during the ATC, it is necessary to implement moiré interferometry with an environmental chamber that provides convection heating and cooling.  The air inside the chamber must be circulated vigorously to achieve the heating/cooling rate required for a typical ATC condition.  Consequently, the environmental chamber experiences vibrations, which are normally transmitted to the specimen.  Moiré interferometry measures tiny displacements and those inadvertent vibrations can cause the moiré fringes to dance at the vibration frequency.  The real-time moiré setup has been developed to cope with the vibrations