naa a22 4500 510800955 CHVBK 20180411092758.0 cr unu---uuuuu 180411e20130601xx s 000 0 eng 10.1007/s11664-013-2475-5 doi (NATIONALLICENCE)springer-10.1007/s11664-013-2475-5 Thermal Cycling Reliability of Sn-Ag-Cu Solder Interconnections—Part 2: Failure Mechanisms [Elektronische Daten] [Jussi Hokka, Toni Mattila, Hongbo Xu, Mervi Paulasto-Kröckel] Part1 of this study focused on identifying the effects of (i) temperature difference (ΔT), (ii) lower dwell temperature and shorter dwell time, (iii) mean temperature, (iv) dwell time, and (v) ramp rate on the lifetime of ball grid array (with 144 solder balls) component boards. Based on the characteristic lifetime, the studied thermal cycling profiles were categorized into three groups: (i) highly accelerated conditions, (ii) moderately accelerated conditions, and (iii) mildly/nonaccelerated conditions. In this work, the observed differences in component board lifetime are explained by studying the failure mechanisms and microstructural changes that take place in the three groups of loading conditions. It was observed that, under the standardized thermal cycling conditions (highly accelerated conditions), the networks of grain boundaries formed by recrystallization provided favorable paths for cracks to propagate intergranularly. It is noteworthy that the coarsening of intermetallic particles was strong in the recrystallized regions (the cellular structure had disappeared completely in the crack region). However, under real-use conditions (mildly/nonaccelerated conditions), recrystallization was not observed in the solder interconnections and cracks had propagated transgranularly in the bulk solder or between the intermetallic compound (IMC) layer and the bulk solder. The real-use conditions showed slight coarsening of the microstructure close to the crack region, but the solder bulk still included finer IMC particles and β-Sn cells characteristic of the as-solidified microstructures. These findings suggest that standardized thermal cycling tests used to assess the solder interconnection reliability of BGA144 component boards create failure mechanisms that differ from those seen in conditions representing real-use operation. TMS, 2013 Reliability nationallicence thermal cycling nationallicence thermal shock nationallicence microstructure nationallicence recrystallization nationallicence accelerated lifetime test nationallicence Hokka Jussi Department of Electronics, Aalto University, 00076, Aalto, Finland aut Mattila Toni Department of Electronics, Aalto University, 00076, Aalto, Finland aut Xu Hongbo Department of Electronics, Aalto University, 00076, Aalto, Finland aut Paulasto-Kröckel Mervi Department of Electronics, Aalto University, 00076, Aalto, Finland aut Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/6(2013-06-01), 963-972 0361-5235 42:6<963 2013 42 11664 https://doi.org/10.1007/s11664-013-2475-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11664-013-2475-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hokka Jussi Department of Electronics, Aalto University, 00076, Aalto, Finland aut NATIONALLICENCE 700 1- Mattila Toni Department of Electronics, Aalto University, 00076, Aalto, Finland aut NATIONALLICENCE 700 1- Xu Hongbo Department of Electronics, Aalto University, 00076, Aalto, Finland aut NATIONALLICENCE 700 1- Paulasto-Kröckel Mervi Department of Electronics, Aalto University, 00076, Aalto, Finland aut NATIONALLICENCE 773 0- Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/6(2013-06-01), 963-972 0361-5235 42:6<963 2013 42 11664 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 510800955 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer