Nowadays, micro loudspeakers are part of all mobile electronic devices such as smart phones, tablets and laptops. This market is estimated to demand more than one billion microspeakers per year and is still growing. A manufacturing of the speakers on silicon wafers can have distinctive advantages over conventional manufacturing like high accuracy and reproducibility as well as low-cost batch processing and new packaging possibilities. For the first time, Fraunhofer ENAS shows research results of a loudspeaker manufactured in MEMS technology. A thin layer of metallic glass is used as membrane of the MEMS speaker. Due to their amorphous microstructure, metallic glasses exhibit superior mechanical properties in comparison to crystalline materials. It can be deposited with standard micro technology processes. In combination with dispensed magnetic paste and a micro coil, an electrodynamic actuator has been fabricated and is exhibited at the Fraunhofer ENAS booth no A-0 at the nanomicro biz 2015. The coil is manufactured in copper technology, which has been developed by the Center for Microtechnologies of the TU Chemnitz.

The researchers also show further actuators like a RF switch, a tunable Fabry-Pérot interferometer and actuators for active flow control as well as MEMS technologies.

Fraunhofer ENAS exhibits samples of contacting and bonding of MEMS devices by aerosol jet printing. This non-contact direct-writing technology is a selective deposition process. This additive process allows not only processing a wide variety of materials but can be performed onto a wide variety of substrates without conventional masks or thin-film equipment. By depositing electrical conductive materials, electrical interconnects can be realized over topographic structures and surfaces. In most instances, the deposited materials consist of metallic nanoparticles. To increase the conductivity of the deposited porous metal particles a selective laser sintering is applied. Thereby, lines width of 25 µm can be performed.

Joerg Froemel from Fraunhofer ENAS gives the talk „MEMS devices enabled by material innovation” about these and further current researches during the 21st International Micromachine Nanotech Symposium on April 22, in Yokohama, Japan.