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Articles you may be interested inThe mechanical robustness of atomic-layer-and molecular-layer-deposited coatings on polymer substrates This article presents studies on using a wedge indentation technique to determine interfacial adhesion properties of low-k dielectric films, namely, methyl-silsesquioxane ͑MSQ͒ and black diamond ͑BD™͒films, both on a Si substrate. Interfacial crack initiation and propagation processes in the MSQ/Si system are studied by using focused-ion-beam sectioning of the indentation impressions created by wedge tips with 90°and 120°of inclusion angles, respectively. Furthermore, the indentation induced stress is found to be proportional to the ratio of the indentation volume and the interface delamination crack volume for both plane strain and nonplane strain cases. With this analysis, the interface toughness of the MSQ/Si and BD/Si system, in terms of the strain energy release rate, is determined. The interface toughness for the MSQ/Si system is found to be a value of 1.89± 0.28 J / m 2 for the 90°wedge tip indentation and 1.92± 0.08 J / m 2 for the 120°wedge tip indentation. In addition, using the 120°wedge tip, the interface toughnesses of the BD films on the Si substrate with 200 and 500 nm thicknesses are found to be the values of 6.62± 1.52 and 6.35± 2.27 J / m 2 , respectively.

Fabricating through-silicon vias (TSVs) is challenging, especially for conformally filled TSVs, often hampered by the seam line and void inside the TSVs. Stress-assisted void growth in TSVs has been studied by finite element stress modeling and x-ray computed tomography (XCT). Because x-ray imaging does not require TSVs to be physically cross-sectioned, the same TSV can be imaged before and after annealing. Using 8 keV laboratory-based XCT, voids formed during copper electroplating are observed in as-deposited samples and void growth is observed at the void location after annealing. We hypothesize that the mechanism generating voids is hydrostatic stress-assisted void growth. Stresses in a copper-filled TSV with a pre-existing void were simulated by finite element methods. The peaks of the hydrostatic stress and its gradient are shown to be around the edge of the void. Comparing simulated results and experimental data shows that void growth in TSVs is stress-assisted: v acancies diffuse and coalesce at the void as a result of the hydrostatic stress gradient

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