• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.592-597
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• 2015

3D-IC is a novel semiconductor packaging technique stacking dies to improve the performance as well as the overall size. TSV is ideal for 3D-IC because it is convenient for stacking and excellent in electrical characteristics. However, due to high-density and micro-size of TSVs, they should be tested with a non-invasive manner. Thus, we introduce a TSV test method on test prober without a direct contact in this paper. A capacitive coupling effect between a probe tip and TSV is used to discriminate small TSV faults like voids and pin-holes. Through EM simulation, we can verify the size of eye-patterns with various frequencies is good for TSV test tools and non-contact test will be promising.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.313-316
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• 1998

Conjugated oligomers have been already used as active layers in field effect transistors, photodiodes and electroluminescent devices. Particularly thiophene oligomers such $\alpha$ -sexithiophene($\alpha$-6T) attract great interest for its prospective app1ications in large-area flexible displays. In this study, we investigated the contact properties between the organic semiconductor $\alpha$-6T and metals such as Au(Gold), Ag(Silver), Cr(Chromium), Al(Aluminum), Cr(Chromium). Using the Transmission Line Model(TLM) method, specific contact resistances of the metal lines in contact with the $\alpha$-6T were determined. From the current-voltage characteristics, electrical conductivity of the $\alpha$-6T films is found.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1897-1902
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• 2004

Numerical analysis of the heat transfer associated with droplet impact on a hot solid surface is performed by solving the mass, momentum and energy equations for the liquid-gas region. The deformed droplet shape is tracked by a level set method which is modified to achieve volume conservation during the whole calculation procedure and to include the effect of contact angle at the wall. The numerical method is validated through test calculations for the cases reported in the literature. Based on the numerical results, the effects of advancing/receding contact angle, impact velocity and droplet size on the heat transfer during droplet impact are quantified.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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• pp.72-74
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• 2002

A submicron contact scheme using $WN_x$ diffusion barrier has been suggested for multilevel interconnect structure. The contact resistance of $0.4\times0.48\mu\textrm{m}^2$ size Al/WN/Ti/$n^+$-Si is 120-140 $\Omega$ and the leakage current density is below than $10^{-16}$$-10^{-15}A/\mu\textrm{m}^2$. The effect of F atoms on the submicron contact has been investigated with the nuclear resonance analysis method.

• Structural Engineering and Mechanics
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• v.72 no.6
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• pp.775-783
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• 2019

The present study deals with the numerical analysis of the symmetric contact problem of two bonded layers resting on an elastic half plane compressed with a rigid punch. In this context, Finite Element Method (FEM) based software called ANSYS and ABAQUS are used. It is assumed that the elastic layers have different elastic constants and heights and the external load is applied to the upper elastic layer by means of a rigid stamp. The problem is solved under the assumptions that the contact between two elastic layers, and between the rigid stamp are frictionless, the effect of gravity force is neglected. To validate the constructed model and obtained results a comparison is performed with the analytical results in literature. The numerical results for normal stresses and shear stresses are obtained for various parameters of load, material and geometry and are tabulated and illustrated.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.57-62
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• 2013

Because of high torque and easiness of speed control, Direct Current(DC) motors have been used for a long time. But, its applications are limited in circumstance and performance, since they contained brush and commutator. The commutation characteristic gives effect to life and performance of the DC motor. Naturally, the commutation characteristic analysis is strongly required. In this paper, With the result of finite element analysis, The inductance is calculated each rotor position and applied to the voltage equations coupled with commutation equation. Also, contact resistances of brush/commutator assembly are considered using contact area and brush width converted with commutator segments. The time derivative term in the differential equation is solved in time difference method. This algorithm was applied to 2-pole shunt DC motor. We considered commutation characteristic by changing contact resistance between brush and commutator segment.

• Textile Coloration and Finishing
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• v.17 no.6 s.85
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• pp.36-41
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• 2005

The effects of low temperature plasma treatment on the properties of three types of foams, polyurethane(PU), injection phylon(IP), and phylon(PH) that used for footwear mid-sole were examined. The change of surface properties of foams were characterized by electron scanning microscope, contact angle measurement, and universal testing machine. Adhesion was tested by T-peel tests of plasma treated foams/polyurethane adhesive joints. The contact angle of three types of foams were decreased dramatically with the plasma treatment time, specifically noticeable in the case of phylon(Ph). It has shown the relationship with the contact angle of phylon(PH) and the distance between electrode and samples. The peel strength of foams were increased with the increase of plasma treatment time.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.6-9
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• 2010

Surface properties of polytetrafluoroethylene(PTFE) films fabricated by rf-magnetron sputtering system with UV surface treatment were investigated to increase water contact angle for their hydrophobic property. We found that the surface morphology and water contact angles of PTFE film modified as a function of the UV treatment times using UV-irradiation were influenced. The water contact angle of PTFE film with optimized UV treatment time for 15 minute showed a high hydrophobicity compared with the film without any surface treatment. We thought that it was due to the energy change of PTFE surface with an adhesion improvement to the glass surface as a smoothing a rough surface with needle-shape and/or the enhancement of an interface property as a removing some defects on the surface like a cleaning effect.

• Tribology and Lubricants
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• v.16 no.5
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• pp.373-380
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• 2000

Finite element analysis is performed on the subsurface crack propagation in brittle materials due to sliding contact. The sliding contact is simulated by a rigid asperity moving across the surface of an elastic half-surface containing single and multiple cracks. The single crack, coplanar cracks and parallel cracks are modeled to investigate the interaction effects on the crack growth in contact fatigue. The crack location is fixed and the friction coefficients between asperity and half-space are varied to analyze the effect of surface friction on stress intensity factor for horizontal cracks. The crack propagation direction is predicted based on the maximum range of shear and tensile stress intensity factors. With a coplanar crack, the stress intensity factor was increased. However, with a parallel crack, the stress intensity factor was decreased. These results indicate that the interaction of a coplanar crack increases fatigue crack propagation, whereas that of a parallel crack decreases it.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.1089-1092
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• 2004

This paper deals with the development of a contact-type counting device using a piezoelectric polymer film as a sensor. The piezoelectric and vibration characteristics of the film under a bending vibration were investigated theoretically and experimentally. A counting device, which includes filters, an amplifier, an analog-digital converter, and a display, was designed and fabricated. The performance of the piezoelectric polymer sensor was evaluated in the sense of the responses to contact force, contact frequency, and contact speed. The life and the temperature effect were also investigated for the piezoelectric film sensor.