Unraveling the complex oxidation effect in sintered Cu nanoparticle interconnects during high temperature aging

Zuo, Yang; Robador, Ana; Wickham, M; Mannan, Samjid H.

doi:10.1016/j.corsci.2022.110713

Cited by 7 publications

(4 citation statements)

References 28 publications

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“…In contrast, high-indexed crystallographic planes generally manifest high chemical reactivity due to their large surface energy levels [8,9]. Since metallic materials are generally polycrystalline, improving the surface corrosion and oxidation resistance is critical for metals that are generally exposed to high temperature or corrosive environment, such as Cu-based thermal management materials and Cu interconnections in micro-electromechanical systems (MEMS) [10,11].…”

Section: Introductionmentioning

confidence: 99%

Reorientation Mechanisms of Graphene Coated Copper {001} Surfaces

Song

Yao

et al. 2023

Metals

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Engineering the surface orientation of face-centered cubic (fcc) metals to the close-packed {111} plane can significantly enhance their oxidation resistance. However, owing to the synergetic effect of surface energy density (γ˙) and strain energy density (ω), such close-packed surface orientation can currently only be achieved by atomic-level thin film epitaxy or monocrystallization of polycrystalline metals. In this study, we characterized the microstructures of pure copper (Cu) foil and two types of graphene-coated Cu (Gr/Cu) foils and observed a 12~14 nm thick reconstructed surface layer with the {111} orientation in the high-temperature deposited Gr/{001} Cu surface. Combining the statistical results with thermodynamic analysis, we proposed a surface melting-solidification mechanism for the reconstruction of the Cu surface from {001} orientation to {111} orientation. This process is dominated by Gr/Cu interfacial energy and is particularly promoted by high-temperature surface melting. We also validated such a mechanism by examining Cu surfaces coated by h-BN (hexagonal boron nitride) and amorphous carbon. Our findings suggest a possible strategy to enhance the surface properties of fcc metals via engineering surface crystallography.

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Section: Introductionmentioning

confidence: 99%

Reorientation Mechanisms of Graphene Coated Copper {001} Surfaces

Song

Yao

et al. 2023

Metals

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“…Compared with precious metallic inks such as gold and silver inks, copper inks are attracting increasing attention because of their high electrical conductivity, high electromigration resistance, and especially low price. [8][9][10][11][12] However, copper is easily oxidized and this problem results in poor stability and high sintering temperature of copper inks, [13][14][15][16][17] making them difficult to integrate with the heat-sensitive substrates.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the Mechanism of Plasma‐Induced Curing of Particle‐Free Complex Inks for Manufacturing of High‐Performance Flexible Copper Films and Patterns

Zhang

Cheng

Rui

et al. 2023

Adv Materials Technologies

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Although cost‐effective copper inks show great potential in printed flexible electronics, the poor stability and high sintering temperatures have hindered their practical application seriously. Herein, the mechanism of plasma‐induced curing of particle‐free complex copper inks is investigated systematically to realize the low‐temperature fabrication of high‐performance copper films and patterns for advanced flexible electronics. The relationships among the ink formulations, plasma characteristics, microstructures, and the properties of the printed copper patterns are identified; the mechanisms of plasma‐induced curing of copper complex inks are summarized. The fabricated copper films exhibit high conductivity (4.1 µΩ cm), excellent flexibility (bending at a radius of 2 mm), and environmental stability because of the dense microstructures and robust interface adhesion, comparable to that of electroless‐plated films. Moreover, intricate copper antenna patterns on flexible substrates can be obtained rapidly using direct writing and gravure printing methods. These results provide a feasible low‐temperature route to fabricate high‐performance copper films and patterns, promoting the practical application of low‐cost copper inks in printed flexible electronics.

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“…Grain boundaries are observed to act as nucleating sites for oxide, leading to formation of nanovoids. However, by achieving a dense and homogeneously sintered microstructure (~10% porosity), the oxidation is reported to be significantly limited [10]. Therefore, working with flake type particles offers a substantial advantage in realizing a dense sintered microstructure, which is discussed later in the paper.…”

mentioning

confidence: 99%

“…Two different failure mechanisms were also reported, namely, edge crack mode and void growth mode [9]. Recent studies on Cu nanoparticle sintering have studied the effect of oxidation on the strength of the sintered interconnect after thermal ageing in air [10]. It is reported that the oxidation initially leads to the increase in the density of the sintered microstructure as well as the shear strength by filling the pores, eventually however leading to a drop in shear strength due to coarsening by the growth of copper oxides around the sintered nanoparticles.…”

mentioning

confidence: 99%

Reliability of Copper Sintered Interconnects under Extreme Thermal Shock Conditions

Bhogaraju,

Ugolini,

Belponer

et al. 2024

IMAPSource Proceedings

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Copper flakes-based sinter paste showed high reliability under thermal shock conditions. A dense and homogeneous interconnect was realized while sintering for 5 min at 275°C under 15 MPa bonding pressure, with the flakes showing the unique behavior of stacking over each other to realize a dense and homogeneous interconnect. Porosity under 10% could be achieved. The paste could be sintered under a constant nitrogen flow and did not need a fully inert atmosphere during sintering. Under high stress thermal shock cycling of +175/-65°C, the sintered interconnects showed a drop of 25% in the shear strength values after 1000 TST, consistent with observations made with Ag sintering. Thermal conductivity more than 200 W/mK and electrical conductivity of 20 Ms/m is achieved using the Cu sinter paste.

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Unraveling the complex oxidation effect in sintered Cu nanoparticle interconnects during high temperature aging

Cited by 7 publications

References 28 publications

Reorientation Mechanisms of Graphene Coated Copper {001} Surfaces

Reorientation Mechanisms of Graphene Coated Copper {001} Surfaces

Unraveling the Mechanism of Plasma‐Induced Curing of Particle‐Free Complex Inks for Manufacturing of High‐Performance Flexible Copper Films and Patterns

Reliability of Copper Sintered Interconnects under Extreme Thermal Shock Conditions

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