Underfill and mold compound influence on PoP aging under high current and high temperature stress

In consequence of the general densification of electronic components, the stress being submitted to the packages aggravates while the size of the internal interconnections shrinks. Against the background of an increasing reliability issue, this paper focuses on reliability aspects within PoP assemblies, submitted to high current and mechanical stress conditions. The role of underfill and molding compound (MC) on temperature management, migration phenomena and stress reduction in a ball grid array (BGA) was investigated. Therefore, thermal-electrical-mechanical finite element simulations were conducted using ANSYS
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and a model of a bump chain being common for PoP structures. With the results, migration mechanisms like electro- or thermo-induced migration in bumps were calculated.