The process (to the Open Access Paper) is based on the agglomeration of microfine powder (particles) by atomic layer deposition (ALD). First, a mold, for example microcavities in a silicon substrate, is filled with loose powder. The particles are then bonded together to form mechanically stable structures by ALD deposition at comparatively low temperatures. In this process, the gases of the ALD deposition penetrate through the entire collection of particles and form a layer several tens of nanometers thick around each particle. As a result, the particles are bonded together over the entire depth of the microcavities (up to about 700 µm) to form a porous three-dimensional body. The resulting PowderMEMS structures are shrinkage-free, mechanically stable and thermally resistant. Structure dimensions between 30 micrometers and several millimeters can be realized with high precision at the substrate level.
Thanks to the almost perfect encapsulation by the ALD layer, the individual particles within a porous 3D body are protected from external influences. Substrates with embedded porous 3D bodies survive standard MEMS and IC manufacturing processes up to 400 °C without damage, allowing extensive post-processing in a clean room. In addition to PowderMEMS technology, ISIT has extensive expertise and cleanroom equipment to realize complete components. Pre- and post-processing by numerous clean room processes allow the optimal integration of PowderMEMS components to improve existing or realize new microsystems.
Depending on the series volume and requirements, the production of developed components can take place on site or be transferred accompanied by ISIT.