Constraining effects of lead-free solder joints during stress relaxation
- Author(s)
- Peter Zimprich, Usman Saeed, Brigitte Weiss, Herbert Ipser
- Abstract
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(s)
- Physics of Nanostructured Materials, Department of Functional Materials and Catalysis
- Journal
- Journal of Electronic Materials
- Volume
- 38
- Pages
- 392-399
- No. of pages
- 8
- ISSN
- 0361-5235
- DOI
- https://doi.org/10.1007/s11664-008-0604-3
- Publication date
- 2009
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 104003 Inorganic chemistry, 103018 Materials physics
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/constraining-effects-of-leadfree-solder-joints-during-stress-relaxation(a1adb289-e5d0-44d6-8c6f-d553c037bd09).html