Advances in delamination modeling of metal/polymer systems: continuum aspects

Adhesion and delamination have been pervasive problems hampering the performance and reliability of micro-and nano-electronic devices. In order to understand, predict, and ultimately prevent interface failure in electronic devices, development of accurate, robust, and efficient delamination testing and prediction methods is crucial. Adhesion is essentially a multi-scale phenomenon: at the smallest scale possible, it is defined by the thermodynamic work of adhesion. At larger scales, additional dissipative mechanisms may be active which results in enhanced adhesion at the macroscopic scale and are the main cause for the mode angle dependency of the interface toughness. Undoubtedly, the macroscopic adhesion properties are a complex function of all dissipation mechanisms across the scales. Thorough understanding of the significance of each of these dissipative mechanisms is of utmost importance in order to establish physically correct, unambiguous values of the adhesion properties, which can only be achieved by proper multi-scale techniques. The topic “Advances in Delamination Modeling” has been split into two separate chapters: this chapter discusses the continuum aspects of delamination, while the next chapter deals with the atomistic aspects of interface separation. The chapter starts with a concise overview of the theory on interface fracture mechanics, followed by five applications: (1) buckling-driven delamination in flexible displays, in which a combined numerical-experimental approach is used to establish macroscopic adhesion properties, as a function of mode angle; (2) a multi-scale method to identify the relevant dissipative mechanisms in fibrillating metal/elastomer interfaces that are encountered in stretchable electronics; (3) analysis and prediction of a particular microscale dissipative mechanism at patterned (roughened) interfaces, as a result of the competition between adhesive and cohesive failures; (4) advanced model parameter identification by integrated digital image correlation which essentially eliminates the need for calculating displacements from images prior to parameter identification; and (5) the modeling of the sintering behavior of Ag particles in a thermal interconnect material.