Abstract:
Many materials now a day used in Micro Electromechanical Systems (MEMS) were not
considered as mechanical material before. So their mechanical properties are not well known
which are very important to predict their specifications like sensitivity, range, and the life which
are very important for their reliability. These materials are used in many real time-critical
applications where a minor error can cause serious damage just like the accelerometer used for
impact detection in automobiles to activate airbags. Thus the mechanical properties should be
exactly known then we can define the device characteristics. Similarly, many other applications
like in aviation, aerospace, and telecommunication, etc. The mechanical properties of the material
used in the MEMS devices should be exactly known for their reliable and safer use. Out of these
mechanical properties yield strength of a material has a critical role in the response of a device.
There are many challenges in material testing at micron level like the generation of force with such
fine resolution, load sensing, adjustment of the specimen, etc. Most of the researchers have used a
monolithically fabricated specimen with a testing mechanism that limits the type of test materials.
Secondly, for separately fabricated specimens the mounting and collection of specimens to the test
structure before and after the test is a challenge. The main objective of this thesis is to design a
generalized MEMS-based testing machine that can find the yield strength of different thin films at
the MEMS level. The main focus of our work is to make the load application and sensing the more
reliable and easier. The biaxial testing mechanism in used with Chevron type electrothermal
actuator for force application and gap, an anti-gap capacitive sensor to find the yield strength. The
proposed design is validated through FEM analysis on ANSYS.
