• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.1
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• pp.16-20
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• 2021

In this study, we tried finding new materials to improve the stain resistance properties of polymer insulating materials. Using the filtered vacuum arc source (FVAS) with a graphite target source, DLC thin films were deposited on silicon and polymer insulator substrates depending on their thickness to confirm the surface properties, physical properties, and structural properties of the thin films. Subsequently, the possibility of using a DLC thin film as a protective coating material for polymer insulators was confirmed. DLC thin films manufactured in accordance with the thickness of various thin films exhibited a very smooth and uniform surface. As the thin film thickness increased, the surface roughness value decreased and the contact angle value increased. In addition, the elastic modulus and hardness of the DLC thin film slightly increased, and the maximum values of elastic modulus and hardness were 214.5 GPa and 19.8 GPa, respectively. In addition, the DLC thin film showed a very low leakage current value, thereby exhibiting electrical insulation properties.

• Journal of the Korean Vacuum Society
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• v.18 no.2
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• pp.97-101
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• 2009

In the modem semiconductor industry, the progress that consumes the most capital and labor is cleansing process. Cleansing process is to remove impurities that can affect the operation of the device and deteriorate its function. Especially, Photoresist (PR) progress that etches the device always requires cleansing at the end of the progress. Also, HDI-PR (High-Dose Ion-implanted Photoresist) created from PR progress is difficult to remove. Thus, in modem IC cleansing, many steps of cleansing are used, including dry and wet cleansing. In this paper, we suggested to combine existing dry-cleansing and wet-cleansing, each represented by plasma cleansing and stripper solution, as Plasma Liquid-Vapor Activation (PLVA). This PLVA method enhances the effect of existing cleansing solution, and decreases the amount of solution and time required to strip. We stripped HDI-PR by activated solution and measured surface hardness and Young's modulus by Nano-indenter. Nano-indenter is the equipment that determines the hardness and the modulus of elasticity by indenting nano-sized tip with specific shape into the surface and measuring weight and z-axis displacement. We measured the change of surface hardness and Young's modulus before and after the cleansing. As a result, we found out that the surface hardness of the sample sharply decreased after the cleansing by plasma-activated PR stripper solution. It can be considered that if physical surface-cleansing process is inserted after this, more effective elimination of HDI-PR is possible.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1744-1748
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• 2007

In this study, the Johnson-Kendall-Roberts (JKR) theory was combined with the instrumented indentation technique (IIT) to evaluate work of adhesion and modulus of elastomeric polymer. Indentation test was used to obtain the load-displacement data for contacts between Tungsten Carbide indenter and elastomeric polymer. And the JKR contact model, contrived to take viscoelastic effects of polymer into account, was applied to compensate the contact area and the elastic modulus which Hertzian contact model would underestimate and overestimate, respectively. Besides, we could obtain the thermodynamic work of adhesion by considering the surface energy in this contact model. In order to define the relation between JKR contact area and applied load without optical measuring of contact area, we used the relation between applied load and contact stiffness by examining the correlation between JKR contact area and stiffness through dimensional analysis with 14 kinds of elastomeric polymer. From this work, it could be demonstrated that the interfacial work of adhesion and elastic modulus of compliant polymer can be obtained from a simple instrumented indentation testing without area measurement, and provided as the main algorithm of compliant polymer characterization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.429-429
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• 2008

The structural stability and the elastic modulus of hexagonal ZnO nanowires and nanotubes are investigated using atomistic simulations based on the shell model. The ZnO nanowire with (10-10) facets is energetically more stable than that with (11-20). Our calculations indicate that the structural change of ZnO nanowires with (10-10) facets is sensitive to the diameter. With decreasing the diameter of ZnO nanowires, the unit-cell length is increased while the bond-length is reduced due to the change of surface atoms. Unlike the conventional layered nanotubes, the energetic stability of single crystalline ZnO nanotubes is related to the wall thickness. The potential energy of ZnO nanotubes with fixed outer and inner diameters decreases with increasing wall thickness while the nanotubes with same wall thickness are independent of the outer and inner diameters. The transformation of single crystalline ZnO nanotubes with double layer from wurtzite phase to graphitic suggests the possibility of wall-typed ZnO nanotubes. The size-dependent Young's modulus for ZnO nanowires and nanotubes is also calculated. The diameter and the wall thickness play a significant role in the Young's modulus of single crystalline ZnO nanowires and nanotubes, respectively.

• Macromolecular Research
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• v.12 no.3
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• pp.293-302
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• 2004

We added surface-modified silica nanoparticles to poly(ethylene 2,6-naphthalate) (PEN) to investigate their effect on the mechanical properties on the PEN nanocomposite material. The torque and total torque values of the composites decreased in the silica nanoparticle composites. The tensile modulus of the composites reinforced with unmodified silica nanoparticles increased upon increasing the silica content, while the tensile strength and elongation decreased accordingly. In contrast, stearic acid-modified, silica nanoparticle reinforced PEN composites exhibited an increase in elongation and a decrease in tensile modulus upon addition of the silica nanoparticles because the stearic acid that had adsorbed onto the surface of the silica nanoparticle in multilayers could act as a plasticizer during melt compounding. Stearic acid modification had a small effect on the crystallization behavior of the composites. We calculated theoretical values of the tensile modulus using the Einstein, Kerner, and Nielsen equations and compared these values with the experimental data obtained from the composites. The parameters calculated using the Nielsen equation and the Nicolais- Narkis model revealed that the interfacial adhesion between silica nanoparticles and the PEN matrix could be improved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.89-90
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• 2007

This paper presents the mechanical properties of 3C-SiC thin film according to 0, 7, and 10% carrier gas $(H_2)$ concentrations using Nano Indentation. When carrier gas $(H_2)$ concentration was 10%, it has been proved that the mechanical properties, elastic modulus and hardness, of 3C-SiC are the best of them. In the case of 10% carrier gas concentration, Young's modulus and Hardness were obtained as 367 GPa and 36 GPa, respectively. When the surface roughness according to $H_2$ concentrations was investigated by AFM (atomic force microscope), when $H_2$ concentration was 10%, the roughness of 3C-SiC thin was 9.92 nm, which is also the best of them. Therefore, in order to apply poly 3C-SiC thin film to MEMS applications, $H_2$ concentration's rate should increase to obtain better mechanical properties and surface roughness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.697-698
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• 2010

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.247-254
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• 2000

In this study, the reinforcing effect of micropile for weathered rock is analysed by laboratory model tests. Especially, the effect of the number, the surface roughness, and length of micropile are focused. The results of tests are as follows: $\circled1$ The deformation modulus of reinforced ground is less than equivalent deformation modulus, and $\circled2$ Increasing effect of unconfined compressive strength is not large as times as increasing the number of micropile.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.188-200
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• 2002

In this study, a pavement evaluation method is introduced by a case study of the measurement data obtained in Incheon International Airport. Based on the results obtained by both visual inspection and automobile inspection equipments, the pavement surface condition is evaluated and used for maintenance and rehabilitation strategy for pavement. In addition, the special attention was given to the back calculation and solution technique of E-modulus by FWD's deflection data in Pavement.

• Macromolecular Research
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• v.16 no.5
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• pp.411-417
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• 2008

The surfaces of henequen fibers, which can be obtained from the leaves of agave plants, were treated with two different media, tap water and sodium hydroxide, that underwent both soaking and ultrasonic methods for the fiber surface treatment. Various biocomposites were fabricated with untreated and treated, chopped henequen fibers and polypropylene using a compression molding method. The result is discussed in terms of interfacial shear strength, flexural properties, dynamic mechanical properties, and fracture surface observations of the biocomposites. The soaking (static method) and ultrasonic (dynamic method) treatments with tap water and sodium hydroxide at different concentrations and treatment times significantly influenced the interfacial, flexural and dynamic mechanical properties of henequen/polypropylene biocomposites. The alkali treatment was more effective than the water treatment in improving the interfacial and mechanical properties of randomly oriented, chopped henequen/PP bio-composites. In addition, the application of the ultrasonic method to each treatment was relatively more effective in increasing the properties than the soaking method, depending on the treatment medium and condition. The greatest improvement in the properties studied was achieved by ultrasonic alkalization of natural fibers, which was in agreement with the other results of interfacial shear strength, flexural strength and modulus, storage modulus, and fracture surfaces.