Reliability Challenges and Mitigation Measures of Small Body-Sized Components on Complex and High-Layer Count PCBs

Advanced electronic systems such as networking equipment often adopt highly complex printed circuit boards. The high layer count and large thickness of these boards creates new challenges for component and system reliability. An area of concern is accelerated solder joint fatigue. The much-increased stiffness of these PCBs induces large strains on solder joints, which can decrease the lifetime of these connections. Large and critical components receive a great amount of attention, with risk management measures developed for these particular components. At the same time, standard components with smaller body sizes can have surprisingly higher risk attributes. In this work, we evaluate the solder joint reliability of QFN and FBGA components and compare them with a much larger BGA component. In addition, the effects of PCB thickness on the QFN components are assessed using numerical simulation. The results demonstrate that packaging construction and component pin layout are dominant factors in determining board-level solder joint reliability. PCB layout optimization can provide some level of stress relief, but effectiveness and adoption can be limited by individual component and product designs.