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Reactive nanometer multilayers as tailored heat sources for joining techniques

: Dietrich, G.; Gawlitza, P.; Braun, S.; Leson, A.

VDI-Wissensforum GmbH:
Nanofair 2009. Proceedings. CD-ROM : 7th International Nanotechnology Symposium, New Ideas for Industry. May 26 - 27, 2009, Dresden, Germany
Düsseldorf: VDI Wissensforum, 2009
ISBN: 978-3-00-027076-5
14 S.
International Nanotechnology Symposium (Nanofair) <7, 2009, Dresden>
Fraunhofer IWS ()
chemische Reaktion; Dünnschicht; Hartlöten; Ionenstrahlkathodenzerstäubung; Löten; Mehrfachschicht; mikroelektromechanisches System (MEMS); Nickelaluminiumlegierung; Schweißen; Wärmebedarf; Wärmebehandlung; Wärmebeständigkeit; Wärmequelle

Established joining techniques like welding, soldering or brazing typically are characterized by a large amount of heat input into the components. Especially in the case of heat sensitive structures like MEMS this often results in stress induced deformation and degradation or even in damaging the parts. Therefore, there is an urgent need for a more reliable and reproducible method for joining, which is characterized by a well defined and small heat input for only a short time period. So-called reactive nanometer multilayers offer a promising approach to meet these needs. Reactive nanometer multilayers consist of several hundreds or thousands of alternating nanoscale layers, which can react with each other. Placing a reactive nanometer multilayer between two surfaces already applied with a solder or brazing metal, it can be used as a controllable local heat source. After activating the chemical reaction by an electrical spark, laser pulse or impact, a self-sustaining intermixing reaction starts, which travels the length of the reactive nanometer multilayer resulting in a stable intermetallic material, such as NiAl. The peak temperature of the reaction can be well above 1000 deg C, but it only reaches this temperature for milliseconds, so that the heat is localized to the solder layers. The component remains at room temperature during the entire process. We will present first results in the fabrication of reactive nanometer multilayers by magnetron and ion beam sputter deposition, the fabrication of free standing nanometer multilayers and first joining experiments. Furthermore, we will give an outlook on future developments, such as alternative material combinations for the generation of higher or lower amounts of heat