Interfacial thermal stresses in ACF bonding assembly

• Analytical model considering the nonlocal deformation of assembly was developed.
• Interfacial stresses of short and long ACF assembly were predicted.
• Analytical expression of chip cracking stress was obtained.

The interfacial stresses and chip cracking stress produced because of thermal and mechanical mismatch in layered electronic assembly are one of main reasons for the failure of electronic packages. The analytical model considering the nonlocal deformation of assembly was developed and applied to predict the interfacial stresses produced due to temperature variation for the short and long anisotropic conductive adhesive film (ACF) bonding assembly. The conditions of zero shear stress at the free ends and self-equilibrated peeling stresses were satisfied. Simultaneously the interfacial stresses of ACF assembly were also predicted by the corrected Suhir’s model, Wang’s model, Ghorbani’s model, local model and finite element model (FEM), which were compared with the results by the present model. In addition, the analytical expression of chip cracking stress was also obtained for layered electronic assembly. The approach is mathematically straightforward and can be extended to include the inelastic creep behavior.