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NCA flip-chip bonding with thermoplastic elastomer adhesives

Fundamental failure mechanisms and opportunities of polyurethane bonded NCA-interconnects
NCA Flip-Chip Kleben mit thermoplastischen Elastomeren - Fundamentale Fehlermechanismen und Chancen von Polyurethan-geklebten NCA Kontakten
: Foerster, Philipp; Linz, Torsten; Krshiwoblozki, Malte von; Walter, Hans; Kallmayer, Christine; Aschenbrenner, Rolf

Fulltext urn:nbn:de:0011-n-1955201 (2.4 MByte PDF)
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Created on: 19.12.2013

Institute of Electrical and Electronics Engineers -IEEE-:
EPTC 2011, 13th Electronics Packaging Technology Conference : 7th-9th December 2011, Singapore
New York, NY: IEEE, 2011
ISBN: 978-1-4577-1983-7
ISBN: 1-4577-1983-5
ISBN: 978-1-4577-1981-3
Electronics Packaging Technology Conference (EPTC) <13, 2011, Singapore>
Conference Paper, Electronic Publication
Fraunhofer IZM ()

NCA flip-chip bonding with thermoplastic elastomer adhesives is a new approach to connect surfaces - mostly with at least one flexible component - electrically and mechanically in one step. Although NCA bonding in general is a well-known process, so far only high-modulus thermosetting epoxy or acrylic adhesives are used. The application of thermoplastic elastomer adhesives identifies new opportunities for bonding flexible substrates but also implies challenges. The process is predestined for cost-efficient and reliable production due to the high availability of polyurethanes as cheap NCA adhesive and its excellent adhesion character. To evaluate fundamental failure mechanisms and long-term stability of the electrical interconnection this work investigates a classical flip-chip assembly with polyurethane film (PU) as NCA adhesive. DMA, TMA and Micro DAC analyses of the adhesive material characterize the fundamental thermo-mechanical behavior. Additionally, an approximation of the master curve allows an estimation of relaxation times. Temperature cycling and thermal load tests confirm that mechanical motions and stress relaxation do not affect reliability of the contacts at temperatures between 40 °C/85 °C.