Engineering model for interfacial stresses of a tri-material assembly with different temperatures in the layers

A model is proposed for the shearing and peeling stresses occurring at the interface of three thin bonded objects to account for different temperatures of the layers by incorporating two temperature ratio parameters. The results are presented for die, die attach and substrate as commonly found in electronic packaging. Both 2D and 3D models are considered for comparison of the analytical results with numerical simulation using finite element method. Both for shearing and peeling stress, the 3D simulation results shows better agreement with analytical solution compare to 2D model.