Dynamic behavior of electronics package and impact reliability of BGA solder joints

An experimental approach to characterize rate-dependent failure envelopes and failure site transitions in surface mount assemblies

“…As discussed earlier, the loading conditions can change the failure site from the solder to the intermetallic layer [15,19], copper trace [18], bond pad [26], etc. The strain energy of deformation is divided among competing failure sites, for example: solder, FR4/Cu-trace and intermetallic layer.…”

“…The failure site dictates the failure mechanism and hence the damage model that is needed to predict durability. Yu et al [15] were the first to report a transition in the failure site from solder to the intermetallic with increasing drop height during drop testing of PWAs. Heaslip et al [16] compared the drop durability of Sn37Pb and Sn95.5Ag3.8Cu0.7 solders and showed that the failure sites and failure mechanisms change with drop height and solder type; while Varghese and Dasgupta conducted high-speed bend tests and showed that the failure site transitions from the solder to the copper trace for specimens with Organic Solderability Preservative (OSP) finish [17,18]; and from the solder to the intermetallic compound (IMC) layer for specimens with Electroless Nickel/Immersion Gold (ENIG) finish [19].…”

The effect of copper trace routing on the drop test reliability of BGA modules

“…It turned out that none of the existing criteria was able to cover the whole sequence of failure on the JEDEC board. Only the new energy criterion SEND, equation (2) dt SEND…”

Test methodology for durability estimation of surface mount interconnects under drop testing conditions

“…Tests conducted by Yu et al [7] and Juso et al [8] indicated that the number of cycles to failure decreased as the PWA strain and strain rate increased. Varghese and Dasgupta [9] ran impact tests on PWAs in the in-plane and out-of-plane orientations and showed that the number of impacts to failure decreased with increasing PWA strain.…”

“…Researchers have also reported different failure sites for different loading conditions. Yu et al [7] observed a transition in the failure site from the solder to the interfacial intermetallic beyond a critical drop height. Varghese and Dasgupta [10] subjected PWAs to flexural strain rates ranging from 10 À3 s À1 to 10 1 s À1 and observed a failure site transition from the solder to the copper trace beyond a critical PWA strain rate.…”