The differences in the fracture behaviour of aluminium-doped ZnO (AZO) films on a flexible substrate subjected to tensile and compressive strains were investigated by using a simple-support bending method. It is found that the crack density and the crack spacing of the AZO films become saturated both in the face-out (FO) and in the face-in (FI) bending tests when the applied strain reaches a certain value. The saturated crack density of the AZO film in the FO bending is higher than that of the film in the FI bending. Crack-initiation strain of the film in the FO bending is smaller than that of the film in the FI bending. The fracture energy of the AZO films is also analyszed. Failure behaviours of the films are examined and exhibit different failure mechanisms for the films subjected to tensile and compressive strains.

No abstract

No abstract

In this paper, a finite element based simulation approach for predicting the effect of microstructure on the stresses resulting from electromigration-induced diffusion is described. The electromigration and stress-driven diffusion equation is solved coupled to the mechanical equilibrium and elastic constitutive equation, where a diffusional inelastic strain is introduced. Here, the focus is on the steady state, infinite life case, when the current-driven diffusion is balanced by the resulting stress gradient. The effect of the crystal orientation in Sn-based solder joints on the limiting current density for an infinite life is investigated and compared to experimental observations in the literature. The effect of the grain structure for Al interconnect lines on the dominant diffusion path and estimates for the effective charge number for two different diffusion paths in Al interconnects determined by matching simulations to experimental measurements of elastic strain components in the literature are also presented.

No abstract