Multiple impact characterization of wafer level packaging (WLP)

Abstract

Wafer level packaging (WLP) of connectivity RF components for mobile devices has emerged as a low-cost and high performance, enabling technology. WLP devices are electronic components with an exposed die that utilizes a ball pitch compatible with standard surface mount technology (SMT) equipment and common printed circuit board (PCB) design techniques. WLP allows the devices to be directly mounted to the PCB of portable devices. One concern of adopting WLP for mobile device applications is reliability under multiple dynamic loading conditions, such as phone drop, due to the fragile nature of the exposed silicon die and the unique packaging designs. A series of dynamic 4-point bend tests were conducted to evaluate the multiple impact reliability of WLP samples. The purpose of this work was to better understand the failure modes and actual reliability of WLP under uniaxial loading, which is commonly observed in mobile drop simulations and tests. The results have been applied to WLP failure prediction for the system-level drop test by using simulation technology.