A comprehensive overview of PowderMEMS-a novel back-end-of-line-compatible microfabrication technology-is presented in this paper. The PowderMEMS process solidifies micron-sized particles via atomic layer deposition (ALD) to create three-dimensional microstructures on planar substrates from a wide variety of materials. The process offers numerous degrees of freedom for the design of functional MEMSs, such as a wide choice of different material properties and the precise definition of 3D volumes at the substrate level, with a defined degree of porosity. This work details the characteristics of PowderMEMS materials as well as the maturity of the fabrication technology, while highlighting prospects for future microdevices. Applications of PowderMEMS in the fields of magnetic, thermal, optical, fluidic, and electrochemical MEMSs are described, and future developments and challenges of the technology are discussed.
Keywords: MEMS integration; energy harvesting; flow sensors; gas sensors; integrated inductors; microfluidics; micromagnets; porous MEMS; powder-based microstructures; three-dimensional microstructures.