Thermal transport and thermal stress in a molybdenum film–glass substrate system

Three-dimensional integration with through-silicon vias is emerging as an approach for improving the performance of integrated circuits. Thermal transport and thermal stress in such designs currently limit their performance and reliability. In this study, the thermal dissipation and thermal stress in a 95.3-nm-thick molybdenum (Mo) film–glass substrate system were investigated using a picosecond laser pump–probe method with four different configurations. This allowed the thermal transport and the generation and propagation of coherent acoustic phonon waves in a Mo film–glass substrate system to be comprehensively studied for the first time. The universality of the superposition model previously proposed for a platinum film on a glass substrate was verified using the present Mo film–glass substrate system from the close agreement between experimental data and theoretical predictions. The thermal transport in the Mo film and the coherent acoustic phonon wave propagation in the Mo film and glass substrate, i.e., thermal diffusivity and longitudinal sound velocity, respectively, were also studied.