We report about a detailed comparison of the additive manufacturing methods inkjet printing (IJP) and aerosol jet printing (AJP). Both technologies are based on the direct-writing approach enabling the non-contact deposition of various materials in flexible patterns, e.g., for printed electronic applications. The deposited pattern elements were classified as (i) drops (IJP) or splats (AJP), (ii) lines, and (iii) squares. These elements can be considered as basic elements of the deposition systems and also of printed electronics. The pattern elements were deposited with IJP and AJP using the same silver nanoparticle ink. After printing, the layers were characterized regarding their morphology by optical and topographical measurement methods as well as regarding their electrical characteristics. It turned out that drops deposited with IJP and splats deposited with AJP can have similar dimensions. However, the shapes of the deposits differ widely. In the case of lines, AJP enables narrower line widths and thinner line thicknesses in comparison to IJP. In IJP, the line morphology varies depending on the direction of the deposition. Finally, the morphology of the deposited lines determines the electrical conductivity. For printed squares, the IJP layers show much higher layer thickness and a different layer topography compared with AJP as result of a higher volume per area deposition of materials

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This paper gives an introduction to glass frit wafer bonding, which is an universally useable technology for encapsulation of microsystems, especially surface micromechanical sensors on wafer level. After a process description, some mechanical as well as electrical characteristics of glass frit bonded wafers are discussed and applications are shown

Reactive bonding is a still new low-temperature joining process that is based on reactive nanoscale multilayer systems. The heat required for the bonding process is generated by a self-propagating exothermic reaction within the multilayer system while the adhesive interconnect is supported by solder films. For microsystem applications, the approach is particularly useful if temperature-sensitive components and materials with high differences in coefficient of thermal expansion have to be joined. In this paper, this is successfully demonstrated for bonding a quartz strain gauge onto a stainless steel membrane and an IR-emitter onto a covar socket by using commercially available nickel/aluminum NanoFoils © . The quality of the bond interface of both demonstrators was investigated by scanning electron microscopy and the strength was determined by a tensile test. On the other hand, integrated microsystem applications beyond die attachment require patterned bond structures, e.g. to form bond frames. Thus, alternative materials were additionally considered that can be directly deposited on silicon substrates by magnetron sputtering, such as aluminum/titanium as well as titanium/amorphous silicon (Ti/a-Si) bilayer systems. The properties of these basic multilayer systems and their reaction products were characterized by differential scanning calorimetry and high-resolution electron microscopy. It is shown that specifically the Ti/a-Si system has substantial potential for direct microsystem technology integration provided the remaining open technological issues can be addressed during future research. In general, the results obtained in this study demonstrate the high potential of the reactive bonding process as a new advantageous assembly technology for the fabrication of future microsystems.

In this study we successfully bonded silicon wafer substrates with metal based thermocompression technology. This technology has the advantage of inherent possibility of hermetic sealing and electrical contact. We used three different kinds of metals: gold, copper and aluminum. We will show the hermeticity, bonding strength and reliability of the different processes and compare the results

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