Effects of SiO_2 film thickness and operating temperature on thermally- induced failures in through-silicon-via structures

摘要

In the present study, the experimental results of the thermally induced failure (fracture) time for the components of copper through-silicon via (TSV) structures and the time for electrical current breakdown (T-BD) are obtained to investigate the effects of the thickness of the SiO2 film and the operating temperature. The numerical scheme is also developed to solve the distributions of transient temperature and stress in the specimen and the equivalent stress/strain for the elements in the Ti, SiO2 and Si components of the TSV structure. The equivalent element stress solutions incorporating with the Johnson-Cook (J-C) fracture model are provided to identify the earliest failure element and time in each of these three components and the T-BD of the structure via the definition for the D factor. The applied models and numerical scheme are confirmed to be trustworthy from the comparison of the numerically predicted and experimental results for these failure time parameters. The effects of the operating temperature of specimen's bottom surface and the film thickness of SiO2 on these time parameters have been evaluated precisely. The T-BD time is elongated by increasing the thickness of either SiO2 or Ti film if the bottom surface is operating at a fixed temperature. The earliest failure time (t(failure)) for the components of Ti, SiO2 and Si wafer and the T-BD are always reduced by the rise of operating temperature.