Mechanical material characterization of Co nanowires and their nanocomposite

Chen, Wen‐Hwa; Cheng, Hsien‐Chie; Hsu, Yu‐Chen; Uang, Ruoh-Huey; Hsu, Jiong-Shiun

doi:10.1016/j.compscitech.2008.09.030

Cited by 23 publications

(13 citation statements)

References 19 publications

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“…This would lead to an excessive FE mesh size, requiring great computer capacity and computational time for simulation, thereby making the simulation infeasible. To simplify the FE modeling so as to make the modeling feasible, macroscopic constitutive modeling [16][17][18][19][20] was performed on both the Cu/ABF layers of the build-up circuit substrate and the Cu/ULK layers, in which they are assumed, as a whole, to be isotropic material. Their equivalent mechanical properties, namely the Young's modulus, CTE, and Poisson's ratio, were determined using the rule of mixture (ROM) technique.…”

Section: Finite Element Analysis and Discussionmentioning

confidence: 99%

An RDL UBM Structural Design for Solving Ultralow-K Delamination Problem of Cu Pillar Bump Flip Chip BGA Packaging

Chen

Wang

et al. 2014

Journal of Elec Materi

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Copper (Cu) pillar bumps tend to induce high thermal-mechanical stress during environmental tests and fabrication processes due to the high hardness of Cu, especially when applied with an ultralow-K (ULK) chip. A previous experiment showed that interfacial delamination was often observed in the ULK layers of conventional Cu pillar bump-type flip chip ball grid array (FCBGA) packages under thermal cycling, where under bump metallurgy (UBM) layers directly sit on the metal pads of silicon chips (herein termed ''direct UBM structure''). In this study, a UBM pad relocation scheme through redistribution layer (RDL) technology (herein termed ''RDL UBM structure'') is proposed to relieve the stress or ULK delamination issue. The proposed technique is tested on Cu pillar bump-type FCBGA packages subjected to thermal loading, the effectiveness of which is demonstrated through finite element stress simulation and experimental reliability tests. Simulation results reveal that the RDL UBM structure can greatly reduce the maximum stress in the ULK layers by as much as about 10% to 44%. Besides, it turns out that the Cu pillar bump-type FCBGA packages with the RDL UBM structure show good interconnect reliability performance in terms of thermal cycling, highly accelerated stress, and high-temperature storage.

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Section: Finite Element Analysis and Discussionmentioning

confidence: 99%

An RDL UBM Structural Design for Solving Ultralow-K Delamination Problem of Cu Pillar Bump Flip Chip BGA Packaging

Chen

Wang

et al. 2014

Journal of Elec Materi

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“…Recently, there are study to evaluate the complete set of effective transversely isotropic properties of a nanocomposite at various nanofibervolume fractions through effective continuum modeling and experimental testing which used Co nanowires as filler materials. The study found significant anisotropy in the effective thermo-mechanical properties of the nanocomposite but surprisingly not in the effective Poisson's ratio and coefficient of thermal expansion (CTE) (Chen et al 2008). Micrometer (5 and 10 μm) long Ag and Cu nanowires having a diameter of 25 nm fabricated using template based method mixed with polystyrene.…”

Section: Nanowire Compositesmentioning

confidence: 95%

Nanowire-Polymer Nanocomposites as Thermal Interface Material

Razeeb¹,

Dalton²

2011

Advances in Nanocomposites - Synthesis, Characterization and Industrial Applications

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“…Due to a different local environment, atoms near a free surface or interface have different equilibrium positions than do atoms in the bulk. Many experiments have reported such sizedependent behavior [67,13,55,5,9,56,28,7,49]. Due to the experimental difficulties related to very small sizes, measured properties for a given material are scattered and sometimes contradictory.…”

Section: Introductionmentioning

confidence: 96%

“…Studies employing MD to analyze size effects in nanostructures can be found for example in [9,1,47,50,14]. Works employing ab initio can be found, e.g.…”

Section: Introductionmentioning

confidence: 99%

Finite element model of ionic nanowires with size-dependent mechanical properties determined by ab initio calculations

Yvonnet

Mitrushchenkov

Chambaud

et al. 2011

Computer Methods in Applied Mechanics and Engineering

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International audienceA finite element procedure for modeling crystalline nanostructures such as nanowires is proposed. The size effects exhibited by nano objects are captured by taking into account a surface energy, following the classical Gurtin Murdoch surface elasticity theory. An appropriate variational form and a finite element approach are provided to model and solve relevant problems numerically.We describe a simplified technique based on projection operators for constructing the surface elements. The methodology is completed with a computational procedure based on ab initio calculations to extract elastic coefficients of general anisotropic surfaces. The FEM continuum model is validated by comparisons with complete ab initio models of nanowires with different diameters where size-dependent mechanical properties are observed. The FEM continuum model can then be used to model similar nanostructures in ranges of sizes or geometries where analytical or atomistic model are limited. The validated model is applied to the analysis of size effects in the bending of an AlN nanowire

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Mechanical material characterization of Co nanowires and their nanocomposite

Cited by 23 publications

References 19 publications

An RDL UBM Structural Design for Solving Ultralow-K Delamination Problem of Cu Pillar Bump Flip Chip BGA Packaging

An RDL UBM Structural Design for Solving Ultralow-K Delamination Problem of Cu Pillar Bump Flip Chip BGA Packaging

Nanowire-Polymer Nanocomposites as Thermal Interface Material

Finite element model of ionic nanowires with size-dependent mechanical properties determined by ab initio calculations

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