Accelerated testing of flip chip packages under dynamic load

Reliability testing of electronic packages is a crucial time factor within the development process of electronic components for automotive applications. Especially during the early stages, a variety of materials has to be evaluated and a faster, more sensitive alternative to established testing procedures is needed. In this study, sinusoidal vibrations of flip chip test boards are investigated within the scope of underfill induced failure modes. Since flip chip devices with modern underfills fail due to delaminations of underfill from the die, a combination of proper preconditioning and vibrational testing was done. It is shown that adhesion of the underfill in flip chip packages can effectively be tested under dynamic load at room temperature. Flip chips at different stages of aging were analyzed using scanning acoustic microscopy, infrared microscopy, scanning electron microscopy and four terminal probing of single bumps. A significant reduction of testing times for the proposed combination of preconditioning and vibration was achieved compared to thermal cycling tests.