کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
544780 | 871783 | 2015 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Thermo-mechanical characterization of passive stress sensors in Si interposer Thermo-mechanical characterization of passive stress sensors in Si interposer](/preview/png/544780.png)
• Passive stress sensors are embedded in an interconnect level of a silicon interposer.
• Their innovative design is based on a rosette-shape of eight copper serpentines.
• Impact of elaboration processes on sensors is characterized.
• A methodology was built up to numerically extract gauge factors of serpentines.
• Sensors sensitivity is assessed using four-point bending and electrical measurement.
Thermo-mechanical stress is a major concern in the frame of 2.5D integration. Passive stress sensors were integrated in a silicon interposer test vehicle to quantify stress at critical locations. The sensors were integrated in a rosette-shape consisting of eight oriented copper serpentines acting like strain gauges. This innovative design allows the calculation of a partial stress tensor, including three planar and one out-of-plane components. Electrical measurements at wafer level, combined with FIB/SEM cross-sections, revealed a strong impact of elaboration processes on the structures electrical characteristics. Numerical simulations using finite element analysis were built to evaluate the sensitivity of copper serpentines to mechanical stress. Finally a dedicated four-point bending tool coupled with a four-terminal resistance measurement setup was fabricated to experimentally extract the values of sensors sensitivity factors. Preliminary results depicted in this paper highlight a sensitivity to stress of distinctly oriented resistors. Several identified sources of data dispersion are inherent to the present measurement configuration. Added-value and limitations of such sensors were underlined, and recommendations regarding the testing strategy were drawn to allow a reliable estimation of the stress fields.
Journal: Microelectronics Reliability - Volume 55, Issue 5, April 2015, Pages 738–746