• Journal of the Microelectronics and Packaging Society
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• v.14 no.1
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• pp.61-68
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• 2007

Interfacial fracture energy(${\Gamma}$) between $Al_2O_3$ thin film deposited by Atomic Layer Deposition(ALD) and sputter deposited Cu electrode for embedded PCB applications is measured from a $90^{\circ}$ peel test. While the interfacial fracture energy of $Cu/Al_2O_3$ is very poor, Cr adhesion layer increases the interfacial fracture energy to $39.8{\pm}3.2g/mm\;for\;Ar^+$ RF plasma power density of $0.123W/cm^2$, which seems to come from the enhancement of the mechanical interlocking and Cr-O chemical bonding effects.

• Journal of Adhesion and Interface
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• v.4 no.1
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• pp.1-8
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• 2003

In this work, the effect of PMR-15 content on the variation of surface free energy of the DGEBA/PMR-15 blend system was investigated in terms of contact angles and mechanical interfacial tests. Based on FT-IR result of the blend system. C=O (1,772, $1,778cm^{-1}$) and C-N ($1,372cm^{-1}$) peaks appeared with imidization of PMR-15 and -OH ($3,500cm^{-1}$) peak showed broadly at 10 phr of PMR-15 by ring-opening of epoxy. Contact angle measurements were performed by using deionized water and diiodomethane as testing liquids. As a result, the surface free energy of the blends gave a maximum value at 10 phr of PMR-15, due to the significant increasing of specific component. The mechanical interfacial properties measured from the critical stress intensity factor ($K_{IC}$) and the critical strain energy release rate ($G_{IC}$) showed a similar behavior with the results of surface energetics. This behavior was probably attributed to The improving of the interfacial adhesion between intermolecules, resulting from increasing the hydrogen bondings of the blends.

• Proceedings of the Korean Fiber Society Conference
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• 1991.06b
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• pp.88-88
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• 1991

• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.16-20
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• 2006

In this paper, we investigated the effects of short-term oxygen plasma treatment of semiconducting silicone layer to improve interfacial performances in joints prepared with a insulating silicone materials. Surface characterizations were assessed using contact angle measurement and x-ray photoelectron spectroscopy (XPS), and then adhesion level and electrical performance were evaluated through T-peel tests and electrical breakdown voltage tests of treated semi-conductive and insulating joints. Plasma exposure mainly increased the polar component of surface energy from $0.21\;dyne/cm^2$ to $47\;dyne/cm^2$ with increasing plasma treatment time and then leveled off. Based on XPS analysis, the surface modification can be mainly ascribed to the creation of chemically active functional groups such as C-O, C=O and COH on semi-conductive silicone surface. This oxidized rubber layer is inorganic silica-like structure of Si bound with three to four oxygen atoms ($SiO_x,\;x=3{\sim}4$). The oxygen plasma treatment produces an increase in joint strength that is maximum for 10 min treatment. However, due to brittle property of this oxidized layer, the highly oxidized layer from too much extended treatment could be act as a weak point, decreasing the adhesion strength. In addition, electrical breakdown level of joints with adequate plasma treatment was increased by about $10\;\%$ with model samples of joints prepared with a semi-conducting/ insulating silicone polymer after applied to interface.

• Elastomers and Composites
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• v.38 no.2
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• pp.139-146
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• 2003

In this work, the influence of ozone treatment on surface properties of carbon black is investigated in terms of X-ray photoelectron spectroscopy (XPS) and contact angles. And their mechanical interfacial properties of the carbon black/acrylonitrile butadiene rubber (NBR) compounds are studied by the crosslink density and composite tearing energy ($G_{IIIC}$). As a result, it is found that the increasing of the ozone concentration leads to an increase of the introduction rate of oxygen-containing functional groups onto carbon black surfaces and to an increase of the surface free energy, resulting in improving both crosslink density and tearing energy ($G_{IIIC}$) of the compounds. The results can be explained by the fact that the oxygen-containing functional groups of carbon black surfaces make an increase of the degree of adhesion at interfaces between carbon blacks and rubber matrix.

• Polymer(Korea)
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• v.26 no.6
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• pp.718-727
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• 2002

In this work, an Ar+ beam was irradiated on carbon fiber surfaces to improve the interfacial shear strength (IFSS) of the resulting composites using an ion assisted reaction (IAR) method h single fiber pull-out test was executed to investigate the basic characteristics of the single Carbon fiber/matrix interface. Based on Greszczuk's geometrical model, the debonding force for pull-out of the fiber from the resins was discussed with the applied ion beam energy as a result, it was known that an ion beam treatment produced the functional groups on fiber surface and etching lines along the fiber axis direction, resulting in increasing the adhesion forces between fibers and matrix, which caused the improvement of the IFSS in a composite system. And, it was also found that the maximum IFSS was shown at 0.8 keV ion beam energy in this system.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.1
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• pp.39-46
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• 2021

The quantitative measurement of interfacial adhesion energy (Gc) of multilayer thin films for Cu interconnects was investigated using a double cantilever beam (DCB) and 4-point bending (4-PB) test. In the case of a sample with Ta diffusion barrier applied, all Gc values measured by the DCB and 4-PB tests were higher than 5 J/㎡, which is the minimum criterion for Cu/low-k integration without delamination. However, in the case of the Ta/Cu sample, measured Gc value of the DCB test was lower than 5 J/㎡. All Gc values measured by the 4-PB test were higher than those of the DCB test. Measured Gc values increase with increasing phase angle, that is, 4-PB test higher than DCB test due to increasing plastic energy dissipation and roughness-related shielding effects, which matches well interfacial fracture mechanics theory. As a result of the 4-PB test, Ta/Cu and Cu/Ta interfaces measured Gc values were higher than 5 J/㎡, suggesting that Ta is considered to be applicable as a diffusion barrier and a capping layer for Cu interconnects. The 4-PB test method is recommended for quantitative adhesion energy measurement of the Cu interconnect interface because the thermal stress due to the difference in coefficient of thermal expansion and the delamination due to chemical mechanical polishing have a large effect of the mixing mode including shear stress.

• The Korean Journal of Ceramics
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• v.3 no.2
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• pp.73-81
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• 1997

In this paper, it is intended to present more reproducible and quantitative method for adhesion assemssement. In scratch test, micromechanical analysis on the stress state beneath the indenter was carried out considering the additional blister field. The interface adhesion was quantified as work of adhesion through Griffith energy approach on the basis of the analyzed stress state. The work of adhesion for DLC film/WC-Co substrate calculated through the proposed analysis shows the identical value regardless of distinctly different critical loads measured with the change of film thickness and scratching speed. On the other hand, uniaxial loading was imposed on DCL film/Al substrate, developing the transverse film cracks perpendicular to loading direction. Since this film cracking behavior depends on the relative magnitude of adhesion strength to film fracture strength, the quantification of adhesion strength was given a trial through the micromechanical analysis of adhesion-dependence of film cracking patterns. The interface shear strength can be quantified from the measurement of strain $\varepsilon$s and crack spacing $\lambda$ at the cessation of film cracking.

• Polymer(Korea)
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• v.24 no.3
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• pp.326-332
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• 2000

The effects of sizing agent on the final mechanical properties of the glass fiber/unsaturated polyester composites were investigated by contact angle measurements at room temperature. In this work, glass fibers were coated by poly(vinyl alcohol), polyester, and epoxy type sizing agent and each property was compared. Contact angles of the sized glass fiber were measured by the wicking method based on Washburn equation using deionized water and diiodomethane as testing liquids. As an experimental result, the surface free energy calculated from contact angle showed the highest value in case of the glass fiber coated by epoxy sizing agent. From measurements of interlaminar shear strength (ILSS) and fracture toughness ( $K_{IC}$ ) of the composites, it was found that the sizing treatment on fibers could improve the fiber/matrix interfacial adhesion, resulting in growing the final mechanical properties. This was due to the enhanced surface free energy of glass fibers in a composite system.

• Composites Research
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• v.21 no.4
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• pp.7-14
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• 2008

Prediction of the load-bearing capacity of an adhesive-bonded Joint is of practical importance for engineers. This paper introduces interface fracture mechanics approach to predict the load-bearing capacity of composite metal bonded joints. The adhesion strength of composite/steel bonding is evaluated in terms of the energy release rate of an interfacial crack and the fracture toughness of the interface. Virtual track closure technique (VCCT) is used to calculate energy release rates, and hi-material end-notched flexure (ENF) specimens are devised to measure the interfacial fracture toughness. Bi-material ENF specimens gave consistent mode II fracture toughness $(G_{IIc})$ values of the composite/steel interface regardless of the thickness of specimens. The critical energy release rates of double-lap joints showed a good agreement with the measured fracture toughness. Therefore. the energy-based interfacial fracture characterization can be a practical engineering tool for predicting the load-bearing capacity of bonded joints.