May 22 – 25, 2023
Europe/London timezone

Direct fabrication of porous 3D microstructures on silicon wafers for MEMS applications

May 22, 2023, 12:05 PM
Oral Presentation (MS22) Manufactured Porous Materials for Industrial Applications MS22


Olaf Andersen (Fraunhofer IFAM Dresden)


A new automated method for the fabrication of functional 3D porous structures directly on planar standard silicon wafers has been developed [1,2]. A typical approach comprises the filling of a mold pattern with micron sized particles of the desired material, and their fixation via atomic layer deposition (ALD). It has been demonstrated that it is possible to manufacture for example micromagnets from NdFeB powders that can be used for energy harvesting.
In order to achieve smallest dimensions and highest filling factors, the utilization of dry powder as the starting material is beneficial. The new approach utilizes the superimposition of high- and low frequency oscillations for particle mobilization in order to achieve optimum mold filling. Additionally, rubber balls are applied for densification of the powder packing.
For verification of the application properties, micromagnets were created from 5 µm NdFeB powder on 8” Si wafers, using the novel automated mold filling technique, as well as an existing manual one for benchmarking purposes. Subsequent atomic layer deposition were utilized to agglomerate the loose NdFeB particles into rigid microstructures. The magnetic properties and inner structure of the NdFeB micromagnets were investigated. It is shown that the novel automated technique outperforms the manual one in major terms. In addition, examples for further materials and applications will be briefly discussed.


[1] German Patent DE 10 2020 209 525 A1.
[2] C. Kostmann; T. Lisec; M. T. Bodduluri; O. Andersen; Micromachines, 2021, 12, 1176.

Participation In-Person
Country Germany
MDPI Energies Student Poster Award No, do not submit my presenation for the student posters award.
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Primary authors

Olaf Andersen (Fraunhofer IFAM Dresden) Mr Cris Kostmann (Fraunhofer IFAM Dresden) Dr Thomas Lisec (Fraunhofer ISIT) Prof. Thomas Weißgärber (Institute of Materials Science, Chair Powder Metallurgy, Technical University of Dresden, Germany)

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