Multilayered electronic components, typically of heterogeneous materials, delaminate under thermal and mechanical loading. A phenomenological model focused on modeling the shape of such interface cracks close to corners in layered interconnect structures for calculating the critical stress for steady-state propagation has been developed. The crack propagation is investigated by estimating the fracture mechanics parameters that include the strain energy release rate, crack front profiles and the three-dimensional mode-mixity along the crack front. The developed numerical approach for the calculation of fracture mechanical properties has been validated with threedimensional models for varying crack front shapes. A custom quantitative approach was formulated based on the finite element method with iterative adjustment of the crack front to estimate the critical delaminatio stress as a function of the fracture criterion and corner angles.
Key Engineering Materials, 2013, Vol 525-526, Issue 509, p. 509-512