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Paste Processing and Structural Properties of Copper Metal-Matrix Composites Containing Short Carbon Fibers

Wurst, H.; Blank, T.; Leyrer, B.; Weber, M.; Ishikawa, D.

Abstract:
This paper reports on the processing behavior of copper sintering paste admixed with short carbon fiber and structural properties of the resultant metal-matrix composite after sintering. Carbon fibers have zero or negative axial thermal expansion coefficient and high tensile strength, promising effective mechanical and thermal properties suitable for doublesided die attach of wide bandgap power semiconductors operating at temperatures above 200deg C. Pastes with filler fractions of 2 to 50% by wet volume were prepared and stencil printed to produce 50 to 200 micrometer thick paste layers, which were susequently dried and sintered in 100% H2 (pressureless, for 30 min at 290deg C) and 100% N2 (for 15min at 260deg C). The fibers had a nominal diameter of 7 micrometer, a 110 nm Ni coating to improve bonding strength with the Cu matrix and were cut to lengths of 100 to 250 micrometer. The stencil printing process was found to cause fiber orientation with small outof- plane tilt and preferential alignment with the printing direction. The composite sintering pastes were then used to sinter silicon dummy chips to copper-clad substrates. Die-shear strengths were determined for a selection of filler concentrations, and correlated with transverse and horizontal cross-sections using optical imaging and scanning acoustic microscopy. ... mehr



Zugehörige Institution(en) am KIT Institut für Prozessdatenverarbeitung und Elektronik (IPE)
Publikationstyp Proceedingsbeitrag
Publikationsjahr 2020
Sprache Englisch
Identifikator ISBN: 978-3-8007-5226-3
KITopen-ID: 1000127795
HGF-Programm 37.01.03 (POF III, LK 01) Batteries in Application
Erschienen in ETG-Fb. 161: CIPS 2020 : 11th International Conference on Integrated Power Electronics Systems, March, 24 – 26, 2020, Berlin, Germany
Verlag VDE Verlag
Seiten 1-6
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