No abstract

No abstract

The reliability of microelectronic components is profoundly influenced by the interfacial fracture resistance (adhesion) and associated progressive debonding behavior. In this study we examine the interfacial fracture properties of representative polymer interfaces commonly found in microelectronic applications. Specifically, interface fracture mechanics techniques are described to characterize adhesion and progressive bebonding behavior of a polymer/metal interface under monotonic and cyclic fatigue loading conditions. Cyclic fatigue debond-growth rates were measured from ~10−11 to 10−6 m/cycle and found to display a power–law dependence on the applied strain energy release rate range, ΔG. Fracture toughness test results show that the interfaces typically exhibit resistance-curve behavior, with a plateau interface fracture resistance, Gss, strongly dependent on the interface morphology and the thickness of the polymer layer. The effect of a chemical adhesion promoter on the fracture energy of a polymer/silicon interface was also characterized. Micromechanisms controlling interfacial adhesion and progressive debonding are discussed in terms of the prevailing deformation mechanisms and related to interface structure and morphology.

Silane adhesion promoters are seeing increasing use in microelectronic packaging applications. For example, they are currently used to adhere the passivating polymer overlayer to oxide. In this paper, we present detailed studies of silane adhesion promoters on the silicon oxide surface. Two common promoters (aminopropyltriethoxysilane and vinyltriethoxysilane) as well as non-functional silanes are investigated. It was found that without a functional end group, long carbon chain silanes can severely degrade adhesion, resulting in interfaces weaker than if no silane is used. Several spin coat solution formulations are used in depositing these films. The resulting surface coverage is examined and quantified using XPS, and the adhesion behavior of various promoter films is tested in sandwich structures using a fracture mechanics approach. Finally, spin-coat solution concentration, surface coverage, and interface fracture energy are compared for the amine functional promoter.

We investigate the effect of loading conditions and process parameters on the failure mode of a Silicon/SiO2/Silane/BCB interface system. Chemical analysis of the fracture surfaces with XPS reveals different crack paths through the structure for the two different loading configurations studied. Furthermore, the curing temperature of the silane coupling agent is shown to have a profound impact on the subcritical debond behavior of the structure. A mechanism responsible for this effect is identified and the XPS data is directly correlated to quantitative information about the resistance of the structure to fracture and subcritical crack growth.