Constraining effects of lead-free solder joints during stress relaxation

Autor(en)

Peter Zimprich, Usman Saeed, Brigitte Weiss, Herbert Ipser

Abstrakt

Reliability and quality control of microelectronics depend on a detailed understanding of the complex thermomechanical properties of miniaturized lead-free solder joints. With the continuous reduction in size of modern electronic devices, including also the size of the solder joints themselves, mechanical constraint effects may become of importance for the reliability of the joints. In the present study stress relaxation tests in tensile mode were performed on model solder joints consisting of eutectic Sn-3.5Ag solder between Cu substrates. The gap size of the joints was varied between 750 ?m and 150 ?m in order to investigate the variation of the mechanical properties as a function of the gap size. As it turned out, stress relaxation was dramatically reduced when the solder gaps became smaller due to constraint effects already well known from earlier measurements of the tensile strength. By employing a traditional creep model, the stress exponents and the activation energies were derived and compared with available data in the literature. The consequences of these constraint effects for the case of thermomechanical fatigue are discussed.

Organisation(en)

Physik Nanostrukturierter Materialien, Institut für Funktionelle Materialien und Katalyse

Journal

Journal of Electronic Materials

Band

38

Seiten

392-399

Anzahl der Seiten

8

ISSN

0361-5235

DOI

https://doi.org/10.1007/s11664-008-0604-3

Publikationsdatum

2009

Peer-reviewed

Ja

ÖFOS 2012

104003 Anorganische Chemie, 103018 Materialphysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/a1adb289-e5d0-44d6-8c6f-d553c037bd09