TY - GEN
T1 - The solder joint reliability assessment of a wafer level CSP package
AU - Chung, Kuan-Jung
AU - Tseng, Chih Hao
AU - Yang, Liyu
PY - 2011/12/1
Y1 - 2011/12/1
N2 - A WLCSP package consists of 2.2 × 2.2 mm 2 silicon die, polyimide-based substrate, and 5 × 5 array of solder balls was used as the test vehicle to evaluate its solder joint reliability. Both package level tests with respect to precondition test, temperature cycling test, unbiased highly accelerated stress test (UHAST), and high temperature storage life (HTSL) test and board level tests regarding temperature cycling test have been included in the test plan. Two different lead free solder ball materials (SAC1205 vs. SAC105), under bump metallurgy (Ti/NiV/Cu vs. plated Cu), and die thicknesses (406 μm vs. 356 μm) were assessed. The test results for the package level assessment present that the test vehicle past criteria for all of these required tests. The test results of temperature cycling (-40°C ∼125°C) for the board level assessment show that these controlled variables have unlike performance in the solder joint reliability (SJR) of the WL-CSP package. The SAC105 shows better solder joint reliability performance than that of SAC1205 to provide 13 % improvement in characteristic life (Weibull distribution). The thick die (406 μm) shows statistically better SJR performance than that of thin die (356 m) to sustain 10% increase in characteristic life (Weibull distribution). On the other hand, standard Ti/NiV/Cu UBM presents statistically equivalent SJR performance as plated Cu in characteristic life. As the results, package design factors of the solder alloy and die thickness play obvious roles in solder joint reliability compared to the factor of UBM. Generally speaking, the WL-CSP package presents appropriate solder joint reliability according to the test results.
AB - A WLCSP package consists of 2.2 × 2.2 mm 2 silicon die, polyimide-based substrate, and 5 × 5 array of solder balls was used as the test vehicle to evaluate its solder joint reliability. Both package level tests with respect to precondition test, temperature cycling test, unbiased highly accelerated stress test (UHAST), and high temperature storage life (HTSL) test and board level tests regarding temperature cycling test have been included in the test plan. Two different lead free solder ball materials (SAC1205 vs. SAC105), under bump metallurgy (Ti/NiV/Cu vs. plated Cu), and die thicknesses (406 μm vs. 356 μm) were assessed. The test results for the package level assessment present that the test vehicle past criteria for all of these required tests. The test results of temperature cycling (-40°C ∼125°C) for the board level assessment show that these controlled variables have unlike performance in the solder joint reliability (SJR) of the WL-CSP package. The SAC105 shows better solder joint reliability performance than that of SAC1205 to provide 13 % improvement in characteristic life (Weibull distribution). The thick die (406 μm) shows statistically better SJR performance than that of thin die (356 m) to sustain 10% increase in characteristic life (Weibull distribution). On the other hand, standard Ti/NiV/Cu UBM presents statistically equivalent SJR performance as plated Cu in characteristic life. As the results, package design factors of the solder alloy and die thickness play obvious roles in solder joint reliability compared to the factor of UBM. Generally speaking, the WL-CSP package presents appropriate solder joint reliability according to the test results.
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U2 - 10.1109/IMPACT.2011.6117252
DO - 10.1109/IMPACT.2011.6117252
M3 - Conference contribution
AN - SCOPUS:84863118193
SN - 9781457713880
T3 - Proceedings of Technical Papers - International Microsystems, Packaging, Assembly, and Circuits Technology Conference, IMPACT
SP - 370
EP - 372
BT - 2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference, IMPACT 2011
T2 - 2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference, IMPACT 2011
Y2 - 18 October 2011 through 21 October 2011
ER -