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As technology continues towards smaller, thinner and lighter devices, more stringent demands are placed on thin polymer films as diffusion barriers, dielectric coatings, electronic packaging and so on. Therefore, there is a growing need for testing platforms to rapidly determine the mechanical properties of thin polymer films and coatings. We introduce here an elegant, efficient measurement method that yields the elastic moduli of nanoscale polymer films in a rapid and quantitative manner without the need for expensive equipment or material-specific modelling. The technique exploits a buckling instability that occurs in bilayers consisting of a stiff, thin film coated onto a relatively soft, thick substrate. Using the spacing of these highly periodic wrinkles, we calculate the film's elastic modulus by applying well-established buckling mechanics. We successfully apply this new measurement platform to several systems displaying a wide range of thicknessess (nanometre to micrometre) and moduli (MPa to GPa).

The intrinsic mechanical properties of a given material strongly depend upon its chemical nature: the organics tend to be soft, but tough, while the inorganic materials are hard but brittle and are prone to fracture. The later characteristic gets even worse for porous materials and is of major concern in the microelectronics industry as porous organosilicates (mainly inorganic) will constitute the insulating layers in future electronic devices. In this paper, we demonstrate that significantly tougher organosilicate glass thin-films prepared by sol–gel process, can be obtained by introducing carbon bridging units between silicon atoms present in the organosilicate network. A fracture energy value of 15 J/m 2 was measured, surprisingly higher than that for dense silicon dioxide (10 J/m 2 ), suggesting mechanical properties that lie somewhere in between those of conventional glasses and organic polymers. We also found that the Young’s modulus follows a linear decay when porosity is introduced, a unique property when compared to traditional organosilicates. As a result, crack resistant films were obtained at high levels of porosity, opening potential applications in the fields of low-k materials for future integrated circuits, membranes, sensors, waveguides, fuel cells and micro-fluidic channels.

Nanoporous glasses are inherently brittle materials that become increasingly fragile with increasing porosity. We show that remarkable increases in fracture energy can be obtained from remnants of the porogen molecules used to create the nanoscale pores. The interfacial fracture energy of ∼2.6 J m −2 for dense methylsilsesquioxane glass films is shown to increase by over one order of magnitude to >30 J m −2 for glasses containing 50 vol.% porosity. The increased fracture resistance is related to a powerful molecular-bridging mechanism that was modelled using bridging mechanics. The study demonstrates that significant increases in interfacial fracture energy may be obtained using strategies involving controlled decomposition of the porogen molecule during processing of nanoporous glasses. The implications are important for a range of emerging optical, electronic and biological technologies that use nanoporous thin films, but are limited by the degradation of mechanical properties with increasing porosity.

In polymer-based nanocomposites the polymeric phase is often confined between stiff inorganic phases. The effect of this confinement on mechanical properties is assessed. The exceptional mechanical properties of polymer nanocomposites are achieved through intimate mixing of the polymer and inorganic phases, which leads to spatial confinement of the polymer phase 1 , 2 , 3 , 4 , 5 . In this study we probe the mechanical and fracture properties of polymers in the extreme limits of molecular confinement, where a stiff inorganic phase confines the polymer chains to dimensions far smaller than their bulk radius of gyration. We show that polymers confined at molecular length scales dissipate energy through a confinement-induced molecular bridging mechanism that is distinct from existing entanglement-based theories of polymer deformation and fracture. We demonstrate that the toughening is controlled by the molecular size and the degree of confinement, but is ultimately limited by the strength of individual molecules.

As technology continues towards smaller, thinner and lighter devices, more stringent demands are placed on thin polymer films as diffusion barriers, dielectric coatings, electronic packaging and so on. Therefore, there is a growing need for testing platforms to rapidly determine the mechanical properties of thin polymer films and coatings. We introduce here an elegant, efficient measurement method that yields the elastic moduli of nanoscale polymer films in a rapid and quantitative manner without the need for expensive equipment or material-specific modelling. The technique exploits a buckling instability that occurs in bilayers consisting of a stiff, thin film coated onto a relatively soft, thick substrate. Using the spacing of these highly periodic wrinkles, we calculate the film's elastic modulus by applying well-established buckling mechanics. We successfully apply this new measurement platform to several systems displaying a wide range of thicknessess (nanometre to micrometre) and moduli (MPa to GPa).

Ultramicrotomy, the technique of cutting nanometers-thin slices of material using a diamond knife, was applied to prepare transmission electron microscope (TEM) specimens of nanoporous poly(methylsilsesquioxane) (PMSSQ) thin films. This technique was compared to focused ion beam (FIB) cross-section preparation to address possible artifacts resulting from deformation of nanoporous microstructure during the sample preparation. It was found that ultramicrotomy is a successful TEM specimen preparation method for nanoporous PMSSQ thin films when combined with low-energy ion milling as a final step. A thick, sacrificial carbon coating was identified as a method of reducing defects from the FIB process which included film shrinkage and pore deformation.

Lowering of the insulator dielectric constant to meet current and future microelectronic device performance requirements has come at the expense of decreasing mechanical properties and increased process damage. Whereas mechanical properties directly impact the robustness of the final package, process damage translates into a decrease in electrical properties, such as EM and TDDB, among others. Both issues can be addressed by the proper selection of a dielectric material, which has high network connectivity, i.e. high modulus, and small, preferably noninterconnected pores. In this chapter, we first define the main integration challenges currently encountered. Then solutions to these issues by both alternative processing approaches and development of advanced novel materials are proposed.

The dielectric properties are reported for nanoporous thin films of poly(methyl silsesquioxane) (MSSQ) for use as an ultralow, dielectric intermetal insulator. Direct experimental conformation is provided that the films have low dielectric constants with low loss up to 10 GHz. Low-frequency measurements are also reported.

In this chapter, the authors focus on two probe‐based techniques‐multiple harmonics atomic force microscopy (AFM) and nanoindentation‐and compare them to surface acoustic wave spectroscopy (SAWS). Here, they present a comparison of experimental results from eight different low‐κ dielectric samples that were analyzed for their mechanical properties with ultralow load nanoindentation, SAWS, and multiharmonics AFM analysis. Multiharmonic microscopy with AFM was performed with the HarmoniX routine on a Bruker Dimension Icon. In multiharmonic AFM the force applied by the cantilever is sufficient to slightly deform the sample surface to extract mechanical property information. Here, experimental measurements of mechanical properties from multiharmonic AFM are described and compared to those from nanoindentation and SAWS measurements. Improved determination of fundamental properties such as Young's modulus provides more refined input to predictive modeling.