at the interface of nanotechnology and life sciences

3D Inspection and Fracture Study of MEMS Membranes

Project description

We are looking for a graduation or internship student in the area of Applied Physics or Electrical Engineering for an assignment to be performed within the L.INT programme “MEMS+ Production and Testing Technologies”. Here is a link where more can be found in general about this programme and its partners. The student will work at the Saxion research group Applied Nanotechnology and in close coordination with the MEMS company Medspray.

The research group AN is active in the area of production of MEMS devices (Micro-Electro-Mechanical Systems), specifically in its scale-up in a cost-effective and environment friendly way. Medspray is a company using MEMS membranes in a range of products such as spray nozzles for medicine inhalers. We partnered together in order to develop testing methods and equipment to study how MEMS membranes behave under repeated cyclical stress.

As the production quantities of MEMS/NEMS products increases – for example due to societal challenges in the area of healthcare – companies will need reliable and accurate production testing and processing techniques. Your contribution in the early development of such technology will be thus of essential importance in the future.

Figure 1: A FEM simulation of a Si MEMS membrane with 850nm thickness under 1kPa pressure. Shown is the von Misses stress in Pa. Deflection scale is 100x enlarged.

The main idea is to use interferometric (3D) imaging of the MEMS membrane under low pressure load as a starting point. The measured data is then fed to an analytical model that estimates the geometric and material properties of the membrane such as the Flexural modulus, internal stresses and thicknesses. Subsequently, a FEM-based simulation at high pressure loads is performed using those estimates as input. Fracture experiments at high load are then compared to the FEM results in order to gain insight in the distribution of the stresses at fracture. The method allows us to study and quantify the behaviour of the tested MEMS membranes under cyclical loads, an area about which little is known in practice. Eventually, the knowledge will be used to improve production testing as well as microfabrication processes for MEMS devices in general.

What tasks do we expect from the graduate to encounter during the project?

  • Understanding the operating principles and physics of MEMS membranes.
  • Understanding the physics of interferometric imaging
  • Refining existing models of MEMS membrane deflection under pressure loads, both analytical and FEM (Comsol)
  • Refining and using an experimental setup for 3D inspection of MEMS membranes under pressure load and validating membrane models and hypotheses
  • Reaching quantitative (data-driven) conclusions

Depending on the study direction, background (University or University of Applied Sciences) as well as the nature of the stay (internship or graduation) there are different levels of depth that can be achieved in the above tasks. These are to be discussed with the student’s study advisor before the beginning of the project so as to fit any requirements.

Study directions: Applied Physics, Mechanical Engineering, Electrical Engineering.

The graduate will be working at the Applied Nanotechnology Research Group at the Saxion but will have regular progress meetings with Medpsray. The assignment will be carried out at the Saxion Nanotechnology Labs at the High Tech Factory. Use of the experimental facilities of Medspray, the University of Twente or SRON is also possible if needed.

Are you interested? Send an email to Aleksandar Andreski at Saxion or to Wietze Nijdam at Medspray .