Thin Film Technology
At the IMPT, the field of thin film technology deals with the design and production of microsystems/MEMS (actuators and sensors). The underlying effect of most of the systems is electromagnetism.
The design of the systems is roughly carried out through analytic and network-based methods. The detailed design is followed up using FEM simulations. For this, the multiphysics simulation tool, ANSYS®, can be used, which makes it possible to perform simulations in the fields of structural mechanics and electromagnetics as well as thermal and fluid dynamic simulations.
The actuators produced at the IMPT use magnetic fields to generate movements. The actuators can be distinguished depending on operating principle (e.g. synchronous (variable) reluctance and hybrid actuators). Not only are linear and rotary micro motors produced, but also the use of these magnetic microactuators is researched (e.g. in the field of microoptics, manipulation of magnetic nanoparticles and implantology).
Sensors that rely on the basis of electromagnetism such as Eddy current sensors, strain sensors, and GMR sensors (ultra-thin, for high-temperature applications), are researched at the IMPT in the field of modular sensors for use in gentelligent applications which also includes temperature sensors.
For the production of microactuators and sensors, a combination of photolithography and galvanic deposition is usually used. By means of photolithography, a temporary form of photoresist is created on Si- or Al203- and filled with functional materials as a result of galvanic deposition. In terms of functional materials, Cu is utilized for coils and wiring. NiFe45/55, NiFe81/19, CoFe and Ni are used for flow leads. Furthermore, epoxy resin SU-8TM and polyimide are used as embedding material and material for membranes. For insulation, layers made of Si3N4 and SiO2 are applied, which are produced using PECVD (Plasma Enhanced Chemical Vapor Deposition). Additionally, ion-beam etching and lift-off are employed for structuring. The production of mechanical components (membranes, cantilevers, spring structures …) takes place through a combination of lithography and etching processes for which dry etching processes (e.g. DRIE, plasma) and wet chemical etching (e.g. KOH, HF) are available.