The microscopic failure mechanisms contributing to the interface fracture toughness of two different pressureless sintered silver interconnects during mixed-mode delamination tests have been studied. Two sintered silver materials are used, one containing nanoparticles (NP) and one containing microflakes (μF). The adhesives are sintered between two 35 × 5 mm2 copper plates electroplated with a silver backside metallisation layer. The fracture behaviour has been monitored under in-situ optical microscopy using the miniature mixed-mode bending setup, combined with post-mortem Scanning Electron Microscopy (SEM) fractography analysis. The significant difference in microstructure between the two interconnect materials results in a pronounced difference in failure behaviour, and resulting mixed-mode interface fracture toughness. The two main competing failure mechanisms are interface delamination and bulk fracture. The NP-interconnect exhibits the typical increase in interface fracture toughness with increasing mode angle, whilst the μF-interconnect shows a never reported before dependency, having a global minimum. The fracture morphologies of the delaminated samples are analysed to explain the difference in failure behaviour using Scanning Electron Microscope (SEM) images. This study offers valuable insights into the complex interplay between the microstructures of the interconnect, failure mechanisms, and the resulting interface fracture toughness.@en

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 atomistic aspects of delamination, while the preceding chapter deals with the atomistic aspects of interface separation. The chapter starts with a concise overview of molecular simulation strategies. Next, examples are provided which represent actual materials being developed for electronic packaging: (1) the prediction of thermomechanical properties of an epoxy molding compound (EMC) and the adhesion properties of an EMC/copper interface by means of MD and CG MD approaches; (2) the modeling of wetting, adhesion, and reliability cycling of die attach and via fills; (3) model scaling to discrete element modeling (DEM) for understanding underfill flow; (4) CG modeling of an epoxy molding compound which relates to the first example; (5) molecular modeling of silicate layers used in planarization and encapsulant layers for flat panel displays; (6) mesoscale modeling of diffusion of organic bases which is of concern to photoresist poisoning; and (7) the prediction of thermomechanical properties of a low-k dielectric material, SiOC:H.

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