The demand for high performance microelectronic products drives the development of 3-D chip-stacking structure. By the introduction of through-silicon-via (TSV) into 3-D flip-chip packages, microelectronic performance is improved by increasing circuit capacity and diminishing signal delay. However, TSV-embedded structure also raises concerns over many reliability issues that come with the steep thermal and mechanical transient responses, increasing numbers of bi-material interfaces and reduced component sizes. In this research, defect initiation induced by thermalmechanical phenomena is studied to establish the early failure modes within 3-D flip-chip packages. It is found that low amplitude but extremely high frequency thermal stress waves would occur and attenuate rapidly in the first hundreds of nanoseconds upon power-on. Although the amplitude of these waves is far below material yielding points, their intrinsic characteristics of high frequency and high power density are capable of compromising the integrity of all flip-chip components. By conducting spectral analysis of the stress waves and applying the methodology of accumulated damage evaluation, it is demonstrated that micron crack initiation and interconnect debond are highly probable in the immediate proximity of the heat source. Such a negative impact exerted by the stress wave in the early, while brief, transient period is recognized as the short time scale dynamic effect. Researched results strongly indicate that short-time scale effects would inflict very serious reliability issues in 3-D flip-chip packages. The fact that 3-D flip-chip packages accommodate a large amount of reduced-size interconnects makes it vulnerable to the attack of short time scale propagating stress waves. In addition, the stacking structure also renders shearing effect extremely detrimental to 3-D flip-chip integrity. Finally, several guidelines effective in discouraging short-time scale effects and thus improving TSV flip-chip package reliability are proposed
