There is great demand for mass production of electronics in wide range of applications including, but not limited to, ubiquitous and lightweight wearable devices for the development of smart homes and health monitoring systems. The advancement of additive manufacturing in electronics industry and academia shows a potential replacement of conventional electronics fabrication methods. However, conductivity is the most difficult issue towards the implementation of highperformance 3D-printed microsystems. As most of 3D printing electronics utilizes ink-based conductive material for electrical connection, it requires high curing temperature for achieving low resistivity (150 °C for obtaining nearly 2.069 x 10-6 .m in copper connects), which is not suitable for most of 3D printing filaments. Thisseriously limits the availability of many lightweight 3D printable materials in microsystem applications because these materials usually have relatively low glass-transition temperatures (< 120 °C). Considering that pristine copper films thicker than 49 nm can offer a very low bulk resistivity of 1.67 x 10-8 .m, a new 3D-printing-compatible connection fabrication approach capable of depositing pristine copper structures with no need of curing processes is highly desirable. Therefore, a new technology with the ability to manufacture 3D-printed structures with high performance electronics is necessary.In this dissertation, novel 3D-printed metallization processes for multilayer microsystems made of lightweight material on planar and non-planar surfaces are presented. The incorporation of metal interconnects in the process is accomplished through evaporating, sputtering and electroplating techniques. This approach involves the following critical processes with unique features: a) patterning of metal interconnects using self-aligned 3D-printed shadow masks, b) fabrication of the temporary connections between isolated metal segments by 3D printing followed with metallization, which host the subsequent electroplating process, and c) fabrication of vertical interconnect access (VIA) features by 3D printing followed with metallization, which enable electrical connections between multilayers of the Microsystem for miniaturization.The presented technique offers approximate bulk resistivity with no curing temperature needed after deposition. Since the ultimate goal is developing lightweight wearable microsystem, this approach demonstrated for two layers and can easily extended for multilayer microsystems enabling realization and miniaturization of complex systems. In addition, the variety of filaments used in 3Dprinters provide opportunities to study implementation of these processes in many electronics fields including flexible electronics. Therefore, the integration of physical vapor deposition systems with 3D printing machines is very promising for the future industry of 3D-printed microsystems.
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