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Thermo-mechanical behavior and reliability issues for high temperature interconnections

 
: Dudek, R.; Sommer, P.; Döring, R.; Herberholz, T.; Fix, A.; Seiler, B.; Rzepka, S.

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Institute of Electrical and Electronics Engineers -IEEE-; IEEE Components, Packaging, and Manufacturing Technology Society:
IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2014. Vol.2 : Lake Buena Vista, Orlando, Florida, USA, 27 - 30 May 2014
Piscataway, NJ: IEEE, 2014
ISBN: 978-1-4799-5268-7
ISBN: 978-1-4799-5267-0
pp.912-919
Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm) <14, 2014, Lake Buena Vista/Fla.>
English
Conference Paper
Fraunhofer ENAS ()

Abstract
Transient liquid phase (TLP) soldering is one option for high temperature interconnects with the advantage of processing conditions being close to those for conventional soldering. In the Cu-Sn system addressed in the paper, a high post-processed melting point of the solder interconnects is achieved due to the formation of Cu6Sn5 and Cu3Sn intermetallic compounds (IMC). A specific low melting solder paste under development can be used if applications for both power and logic electronics are addressed. Metallic particles are embedded in the solder paste. New challenges concerning the thermo-mechanical reliability of these devices arise as the materials properties of the TLP interconnect differ substantially from those known for soft solders. Based on material characterization of pure IMC effective material characteristics of the TLP joint, consisting of a mixture of different constituents, have been derived based on a micromechanical cell model. A cell model was additionally embedded in a resistor joint with effective TLP properties and the local stresses were studied. It is shown that the higher material stiffness and strongly decreasing ductility of the joining material change the potential failure modes of an assembly made by TLP soldering. The new thermo-mechanical failure risks are evaluated for a mounted chip resistor and a power module, an IGBT on DCB substrate, by both conventional FEA and cohesive zone modeling.

: http://publica.fraunhofer.de/documents/N-328305.html