Thin metal films are widely used in modern electro mechanical systems. The need for more integrated functionality and minimization of material and energy consumption leads to miniaturization of these systems. As a consequence, materials are processed on the micro- and nanometer scale. On this scale, material properties become a function of size. To predict performance and reliability, knowledge on the size dependence of material properties is imperative. In this work the unknown size dependence of the copper Young's modulus is determined by electrostatic pull-in experiments performed on bilayer copper-silicon nanocantilevers. The size effect is also predicted with a multi-scale (MS) method. In this method atomistic simulations predict the bulk elastic and surface properties of mono-crystalline silicon (Si) and poly-crystalline copper (Cu). These results are combined to represent the bilayer nanocantilevers of the experiment in a continuum model. The model is verified by comparison with a well documented size effect of the effective Si Young's modulus. It is shown that the experimental method can be used for determining the Young's modulus of thin Cu films in the 10 to 50 nm range. Both the experimental results and the MS simulation results show that there is a strong size effect present in Si and Cu.@en

Debonding of polymer-metal interfaces often involves both interfacial and cohesive failure. This paper extends the investigation of Yao and Qu presented in [Yao Q, Qu J. Interfacial versus cohesive failure on polymer-metal interfaces in electronic packaging - effects of interface roughness. J Electr Packag 2002; 124; 127-34] towards a numerical fracture mechanics model that is used to quantitatively predict the relation between cohesive and adhesive failure on a metal-polymer interface. As example, an epoxy-aluminum interface is investigated. The competition between adhesive and cohesive failure depending on surface roughness parameters will be studied. Understanding of these phenomena could enable the optimization of interface properties for different applications.@en