Quantitative measurement of the stress transfer function in nickel/polyimide thin film/copper thin film structures

The stress transfer behavior in multilayer thin film structures (nickel/polyimide/copper) was measured using x-ray stress analysis. Copper was deposited in various line lengths, and the stress/strain transferred from a loaded Ni substrate to the Cu thin film was measured as a function of line length. It was found that there is incomplete strain transfer from one layer to another, and that the shape of the stress transfer function is similar to that predicted by the shear lag model.© 1995 American Institute of Physics.