◆ Micro-materials fracture problem

　Microdevices such as LSI and MEMS/NEMS are complex structures containing numerous numbers of micro-scale components. The structural integrity of the microdevices, just like an engine or a gear box, depends on the reliability of each minute component. It is therefore critically important to know the mechanical properties of micro-materials under various physical and/or chemical conditions.
We developed a special experimental technique to approach this issue. Micro-specimens were fabricated with an ion-beam processing method, and they were subjected to in situ deformation/fracture tests under electron microscopy. The example shown here (i.e. fracture nucleation from an interface edge) reveals that the scatter of strength value is significantly influenced by the wedge shape. This may be attributable to the effect of granular structure of Cu film.

For more detail, see：

Y. Takahashi, K. Aihara, I. Ashida, K. Higuchi, Y. Yamamoto, S. Arai, S. Muto, N. Tanaka, Evaluation of interfacial fracture strength in micro-components with different free-edge shape, Mechanical Engineering Journal, Vol. 3, No. 6, 2016, ID: 16-00108
(https://doi.org/10.1299/mej.16-00108)

Related studies:

Y. Takahashi, I. Ashida, S. Arai, K. Higuchi, Y. Yamamoto, S. Muto, Interfacial fracture strength evaluation of Cu/SiN micro-components: applicability of the linear fracture mechanics criterion under a hydrogen environment, International Journal of Fracture, Vol. 210, 2018, pp. 223–231 (https://doi.org/10.1007/s10704-018-0269-8)

Y. Takahashi, S. Arai, Y. Yamamoto, K. Higuchi, H. Kondo, Y. Kitagawa, S. Muto, N. Tanaka, Evaluation of interfacial fracture strength in micro-scale components combined with high-voltage environmental electron microscopy, Experimental Mechanics, Vol. 55, 2015, pp. 1047-1056 (https://doi.org/10.1007/s11340-015-0008-2)

Y. Takahashi, H. Kondo, H. Niimi, T. Nokuo, T. Suzuki, Fracture strength analysis of single-crystalline silicon cantilevers processed by focused ion beam, Sensors & Actuators: A. Physical, Vol. 206, 2014, pp. 81–87 (https://doi.org/10.1016/j.sna.2013.11.037)