• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.2
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• pp.151-157
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• 2023

Integrating dielectric materials into LTCC is a convenient method to increase the integration density in electronic circuits. To enable co-firing of the high-k and low-k dielectric LTCC materials in a multi-material hetero-laminate, the shrinkage characteristics of both materials should be similar. Moreover, thermal expansion mismatch between materials during co-firing should be minimized. The alternating stacking of an LTCC with silica filler and that with calcium-zirconate filler was observed to examine the use of the same glass in different LTCCs to minimize the difference in shrinkage and thermal expansion coefficient. For the LTCC of silica filler with a low dielectric constant and that of calcium zirconate filler with a high dielectric constant, the amount of shrinkage was examined through a thermomechanical analysis, and the predicted appropriate fraction of each filler was applied to green sheets by tape casting. The green sheets of different fillers were alternatingly laminated to the thickness of 500 ㎛. As a result of examining the junction, it was observed through SEM that a complete bonding was achieved by constrained sintering in the structure of 'calcium zirconate 50 vol%-silica 30 vol%-calcium zirconate 50 vol%'.

• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.54-65
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• 1994

This research carried out to investigate the effects of inorganic materials in paper sludge on the thermal degradation and of paper sludge addition on physical and mechanical properties of paper sludge-wood particle mixed boards in comparison with unmodified particleboards. Also these unmodified particleboards and paper sludge-wood particle mixed boards were soaked in aqueous solutions of fire-retardant chemicals(diammonium phosphate and zinc chloride), and their fire retardancy were tested by oxygen index method and ISO ignition test to determine the feasibility of paper sludge, industrial waste, as a recyclable resource in fabrication of fire-resisting panels for building material. Since the redrying of fire-retardant treated particleboards and paper sludge-wood particle mixed boards were made by press drying method, this process was a simple and effective method. On the other hand, flexural bending strength and internal bonding strength were also analysed to evaluate mechanical properties through standard method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.429-429
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• 2007

For various applications of liquid crystal displays (LCDs), the uniform alignment of liquid crystal (LC) molecules on treated surfaces is significantly important. Generally, a rubbing method has been widely used to align the LC molecules on polyimide (PI) surfaces. Rubbed PI surfaces have suitable characteristics, such as uniform alignment. However, the rubbing method has some drawbacks, such as the generation of electrostatic charges and the creation of contaminating particles. Thus, we strongly recommend a non contact alignment technique for future generations of large high-resolution LCDs. Most recently, the LC aligning capabilities achieved by ultraviolet and ion-beam exposures which are non contact methods, on diamond-like carbon (DLC) inorganic thin film layers have been successfully studied because DLC thin films have a high mechanical hardness, a high electrical resistivity, optical transparency, and chemical inertness. In addition, nitrogen-doped DLC (NDLC) thin films exhibit properties similar to those of the DLC thin films and a higher thermal stability than the DLC thin films because C:N bonding in the NDLC thin filmsis stronger against thermal stress than C:H bonding in the DLC thin films. Our research group has already studied the NDLC thin films by an ion-beam alignment method. The $SiN_x$ thin films deposited by plasma-enhanced chemical vapor deposition are widely used as an insulation layer for a thin film transistor, which has characteristics similar to those of DLC inorganic thin films. Therefore, in this paper, we report on LC alignment effects and pretilt angle generation on a $SiN_x$, thin film treated by ion-beam irradiation for various N ratios

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.28.2-28.2
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• 2009

Cobalt thin film was fabricated by a novel NH3-based plasma-enhanced atomic layer deposition(PE-ALD) using Co(CpAMD) precursor and $NH_3$ plasma. The PE-ALD Co thin films were produced well on both thermally grown oxide (100 nm) $SiO_2$ and Si(001) substrates. Chemical bonding states and compositions of PE-ALD Co films were analyzed by XPS and discussed in terms of resistivity and impurity level. Especially, we successfully developed PE-ALD Code position at very low growth temperature condition as low as $T_s=100^{\circ}C$, which enabled the fabrication of Co patterns through lift-off method after the deposition on PR patterned substrate without any thermal degradation.

• Journal of the Korean institute of surface engineering
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• v.33 no.2
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• pp.69-76
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• 2000

The rf plasma chemical vapor deposition is a common method employed for diamond or amorphous carbon deposition. Diamond possesses the strongest bonding, as exemplified by a number of unique properties-extraordinary hardness, high thermal conductivity, and a high melting tempera tore. Therefore, it is very important to investigate the synthesis of semiconducting diamond and its use as semiconductor devices. An inductively coupled rf plasma CVD system for producing amorphous carbon films were developed. Uniform temperature and concentration profiles are requisites for the deposition of high quality large-area films. The system consists of rf matching network, deposition chamber, pumping lines for gas system. Gas mixtures with methane, and hydrogen have been used and Si (100) wafers used as a substrate. Amorphous carbon films were deposited with methane concentration of 1.5% at the process pressure of S torr~20 torr, and process temperature of about $750^{\circ}C$. The nucleation and growth of the amorphous carbon films have been characterized by several methods such as SEM and XRD.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.4
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• pp.357-363
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• 2006

Monolithic molecularly imprinted columns were designed and prepared by an in-situ thermal-initiated copolymerization technique for rapid separation of tryptophan and N- CBZ-phenylalanine enantiomers. The influence of polymerization conditions and separation conditions on the specific molecular recognition ability for enantiomers and diastereomers was investigated. The specious molecular recognition was found to be dependent on the stereo structures and the arrangement of functional groups of the imprinted molecule and the cavities in the molecularly imprinted polymer (MIP). Moreover, hydrogen bonding interactions and hydrophobic interactions played an important role in the retention and separation. Compared to conventional MIP preparation procedures, the present method is very simple, and its macroporous structure has excellent separation properties.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.28-30
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• 1994

Ultrasonic for MoSi$_2$/Y. C. Kim, C. K. Namkoong/MoSi$_2$in the silicides has excellence in the oxidation and corrosion resistence. When the solid state bonding sintered-MoSi$_2$/metal or the thermal sprayed coating by powder-MoSi$_2$on the metal are carried out, the defects may be occured at the bonded surface. So, the method for evaluating the existence of the defects by non-destructive inspection is strongly desired. Here, the characteristics of ultrasonic for sintered-MoSi$_2$are elucidated and the possibility of the detection of defects using by ultrasonic is investigated.

• Journal of Sensor Science and Technology
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• v.17 no.4
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• pp.273-280
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• 2008

Monolith aperture-type oxygen sensors with simple structure of YSZ(pin-hole)/Pt/ YSZ(solid electrolyte)/Pt were fabricated by co-firing technique. To enhance the yield of productivity, a couple of YSZ green sheets for diffused barrier and solid electrolyte were prepared by tape-casting and co-firing method. The limit current characteristics of the oxygen sensors were measured between 500 and $650^{\circ}C$ The heating temperature of $600^{\circ}C$ was optimum as a portable oxygen sensor in the range of oxygen concentration from 0 to 75 vol%. Linear proficiency of limit current behavior as a function of oxygen concentration was controlled by the variation of aperture dimension. The fabricated oxygen sensors showed the stable sensing output for 30 days. Gas leakage in bonding area due to warping, cracking and thermal cycling was not found in the period.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.220-223
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• 1996

Mechanical properties of Plasma-Enhanced Chemical Vapor Deposited (PECVD) silicon nitride thin film was studied to determine the feasibility of the film as a passivation layer over the aluminum bonding areas of integrated circuit chips. Ultimate strain of the films in thicknesses of about 5 k${\AA}$ was measured using four-point bending method. The ultimate strain of these films was constant at about 0.2% regardless of residual stress. Intrinsic and residual stresses of these films were measured and compared with thermal shock and cycling test results. Comparison of the results showed that more tensile films were more susceptible to crack- induced failure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.109-110
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• 2016

The recent introduction of Metal spraying method apply to construction and civil steel structure is increasing. In applying the metal spraying lining process of construction and civil steel structure to secure the adhesion strength between the metal thermal spray coating and the steel structure and the highest priority requirements are required bond strength test reliable measurement accordingly. In this study, by calculating the deposition intensity and the standard deviation, coefficient of variation corresponding to the bonding area, unlike the shape of the attachment we compared the results.