Effect of Interfacial Adhesion of Copper/Epoxy under Different Moisture Level

Chan, E.K.L.; Fan, Hongwei; Yuen, M.M.F.

doi:10.1109/esime.2006.1644046

Cited by 7 publications

(5 citation statements)

References 12 publications

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“…Because of the material interface between the EMC and the leadframe is where moisture tends to seep in, the adhesion force decreases rapidly as expected due to moisture induced delamination (Chan et al , 2006). It should be pointed out that the adhesion force of 80 per cent of the initial value, i.e.…”

Section: Resultsmentioning

confidence: 88%

“…The trend shown in Figure 7 reveals that the adhesion force can either increase or decrease depending on both the moisture content and the mold temperature. That is, the effect of moisture content in the EMC on the adhesion force is definite but mixed (Chan et al , 2006). At higher mold temperatures, such as 195 and 205°C, the adhesion force increases to the maximum and then decreases rapidly as the moisture content increases, in contrast, at lower mold temperatures, such as 155 and 165°C, the adhesion force decreases to the minimum first and then increases, i.e.…”

Section: Resultsmentioning

confidence: 99%

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Process factors affecting adhesion of encapsulation molding compounds

Liaw

Chao

Chou

2018

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Purpose The purpose of this paper is to determine the key process factors which affect the adhesion strength of encapsulation molding compounds (EMCs) to leadframes to obtain reliable components without any need to pretreat the leadframe surface. Design/methodology/approach EMCs were molded to Cu leadframes to experimentally quantify the effect of mold temperature, resin viscosity, leadframe oxidation and powder moisture on the adhesion force. Component reliability was assessed by PCT. Findings A higher mold temperature result in a larger adhesion force. The mold temperature of 175°C provides the largest process window. Leadframe oxidation can increase adhesion first, but then decrease it drastically with further oxidation. The powder moisture content has mixed effect on adhesion. Practical implications By molding at 175°C, limiting the wire bonding time and minimizing the powder moisture content, reliable components can be obtained without any need for leadframe surface pretreatment such as plasma cleaning or surface coating. Originality/value Quantify the key process factors which affect the adhesion of EMCs and reveal reason behind the current industrial practice of using the mold temperature of 175°C.

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Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Process factors affecting adhesion of encapsulation molding compounds

Liaw

Chao

Chou

2018

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“…In applying tensile or shear strain in bulk material in MD simulation, the stress-displacement curve can be directly calculated from simulation results, and this relationship describes the relationship of interfacial traction force and interfacial bonding opening displacement during delamination of the bilayer system, which is exactly the cohesive constitutive relation of the interface. Apart from quantifying the traction-separation relation for modeling the interface from empirical approaches, the interface property converted from MD simulation provides the scientific support in explaining the interaction between two materials at the interfacial region from the physics and/or chemistry point of view, which is a more efficient and fundamental approach to evaluate the structural behavior under moisture or other environmental attack [15,21,[119][120][121].…”

Section: Macroscale Model Using Finite Element Methodsmentioning

confidence: 99%

Evaluation of the Moisture Effect on the Material Interface Using Multiscale Modeling

Qin

Lau

2019

Multiscale Sci. Eng.

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Layered material systems are widely seen in various engineering applications such as thin films circuit boards in electronic engineering, lipid bilayer in biological engineering, and adhesive bonding in aerospace and civil engineering applications. However, the durability of the material interface can be seriously affected due to the prolonged exposure to water. Although the experimental studies have shown the reduction in terms of ultimate bond strength and fracture toughness for material interface, the shift in failure mode found in experiment cannot be explained using conventional fracture theory, which is related to the interaction between the water and material interface. To understand the debonding mechanism from a fundamental and comprehensive aspect and bridge knowledge from the atomistic scale to continuum scale, multiscale modeling approach has been proposed to study the debonding behavior of material interface under moisture effect. A number of studies have been conducted using multiscale modeling approach to investigate the debonding of material interface, and it is necessary to summarize these studies to understand the role of water molecules in weakening and diffusing at the material interface using different atomistic models, force fields and upscaling techniques. This paper provides a comprehensive review on the multiscale modeling of interfacial and delamination behavior of layered material system under moisture attack with the focus on the molecular dynamics simulation and finite element modeling. The FRP bonded concrete system is used as a representative to demonstrate the approach of multiscale modeling. The future research direction is recommended, which involves the consideration of roughness of substrate and structural voids at interface for the better understanding of durability issue for interface in layered material system under different environmental conditions.

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“…[15] Hydrogen bonds and covalent bonds supporting the adhesion between polymer and metal are further known to be dissociable by water (or charged species depending on pH), through replacing the donor-acceptor pairs in the former and causing hydrolysis bond cleavage in the latter. [16][17][18][19] The plasticizing and swelling effects of the absorbed moisture could deteriorate the strength of the polymer on a larger length scale. [20] Composition engineering of the composites by increasing inorganic filler loading and modifying resin chemical structure to reduce polarity or introduce steric hindrance were deemed effective in restricting moisture absorption, [21][22][23][24][25] while intrinsically these optimization approaches can hardly escape the trade-off relationship between moisture absorption and adhesion strength, both positively correlated to the population and availability of polar groups.…”

Section: Introductionmentioning

confidence: 99%

Transition Metalβ‐Diketonate Adhesion Promoters in Epoxy‐Anhydride Resin

Cheung

Wilson

et al. 2023

Macromol. Rapid Commun.

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Epoxy to copper adhesion supports the reliability of numerous structures in electronic packaging. Compared to substrate pre‐treatment, processing and cost considerations are in favor of adhesion promoters loaded in epoxy formulations. In this work, first row transition metal β‐diketonates present such a compelling case when added in epoxy/anhydride resins: over 30% (before moisture aging) and 50% (after moisture aging) enhancement in lap shear strength are found using Co(II) and Ni(II) hexafluoroacetylacetonate. From extensive X‐ray photoelectron spectroscopy (XPS) analyses on the adhesively failed sample surfaces, increased population of oxygen‐containing functional groups, especially esters, is linked to the adhesion improvement. Assisted by XPS depth profile on the fractured epoxy side and in situ Fourier‐transform infrared spectroscopy (FTIR), the previously discovered latent cure characteristics endowed by the metal chelates interacting with phosphine catalysts are regarded pivotal for pacing the anhydride consumption and allowing interfacial esterification reactions to occur. Further examinations on the XPS binding energy shifts and dielectric properties of the doped epoxy also reveal metal–polymer coordination that contribute to the adhesion and moisture resistance properties. These findings should stimulate future research of functional additives targeting at cure kinetics control and polar group coordination ideas for more robust epoxy–Cu joints.

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Effect of Interfacial Adhesion of Copper/Epoxy under Different Moisture Level

Cited by 7 publications

References 12 publications

Process factors affecting adhesion of encapsulation molding compounds

Process factors affecting adhesion of encapsulation molding compounds

Evaluation of the Moisture Effect on the Material Interface Using Multiscale Modeling

Transition Metalβ‐Diketonate Adhesion Promoters in Epoxy‐Anhydride Resin

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