Ultrasonic MEMS Testing

On June 1, 2020, we started a collaboration with the Fraunhofer IPMS with the project AkteMUS (“Development of a highly efficient method for active acoustic testing of miniaturized ultrasonic structures in the in substrate and carrier composites” with subprojects of the IPMS “Research and Development of active methods for the characterization of miniaturized ultrasonic structures”). Aim of the project is the development of a new acoustic test method to characterize miniaturized ultrasonic elements after separation from the silicon substrate composite for properties and functional parameters after separation from the silicon substrate composite.

Miniaturized ultrasonic elements can be used for a wide range of applications, from diagnostics to 3-D imaging and must be carefully tested for their functionality before use. One example is the capacitive micromachined ultrasonic transducer (CMUT) from Fraunhofer IPMS, which can be used to determine the bacterial or viral origin of middle ear infections. The use of the capacitive silicon-based ultrasonic transducers enables devices that have the potential to be manufactured in high volumes at very low cost. So far, however, the functional test of these devices has proved to be a major cost driver during the entire manufacturing process: it accounts for up to 40% of the manufacturing costs. The purely electrical test is time-consuming, since the acoustic performance is inferred indirectly from the electrical properties. The test procedure investigated in the AkteMUS project comes very close to the operating conditions of the component and reduces the measurement time with a high number of channels or a high number of channels or a high number of single-channel ultrasonic devices. In general, the research and development project considers active test procedures, which could also be used for other MEMS devices and active principles. Through research-intensive innovations in the areas of acoustic functional testing, as well as the measurement on miniaturized and already isolated devices (frame probing), new powerful and flexible test systems will be developed. In addition, the influence of handling, packaging and environmental influences will be evaluated. In addition to the currently established test scenarios new possibilities and markets for the test of MEMS devices will be explored. The constant development of MEMS sensors and actuators will benefit in the long term in a very broad context from the provision of an efficient test procedure for miniaturized devices in substrate composites through the planned AkteMUS project.

The project will be realized until May 2022 and will be funded by the Sächsische Aufbaubank. The consortium consists of the Fraunhofer IPMS and the aSpect Systems GmbH.