• Transactions on Electrical and Electronic Materials
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• v.12 no.2
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• pp.56-59
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• 2011

The characterization of the chemical mechanical polishing (CMP) process for undensified phophosilicate glass (PSG) film is reported using design of experiments (DOE). DOE has been used by experimenters to understand the relationship between the input variables and responses of interest in a simple and efficient way, and it typically is beneficial for determining the appropriatesize of experiments with multiple process variables and making statistical inferences for the responses of interest. The equipment controllable parameters used to operate the machine consist of the down force of the wafer carrier, pressure on the back side wafer, table and spindle speeds (SS), slurry flow (SF) rate, pad condition, etc. None of these are independent ofeach other and, thus, the interaction between the parameters also needs to be understoodfor improved process characterization in CMP. In this study, we selected the five controllable equipment parameters the most recommendedby process engineers, viz. the down force (DF), back pressure (BP), table speed (TS), SS, and SF, for the characterization of the CMP process with respect to the material removal rate and film uniformity in percentage terms. The polished material is undensified PSG which is widely used for the plananization of multi-layered metal interconnects. By statistical modeling and the analysis of the metrology data acquired from a series of $2^{5-1}$ fractional factorial designs with two center points, we showed that the DF, BP and TS have the greatest effect on both the removal rate and film uniformity, as expected. It is revealed that the film uniformity of the polished PSG film contains two and three-way interactions. Therefore, one can easily infer that process control based on a better understanding of the process is the key to success in current semiconductor manufacturing, in which the size of the wafer is approaching 300 mm and is scheduled to continuously increase up to 450 mm in or slightly after 2012.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.567-572
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• 2013

In houses that use heating and cooling system, most of heat loss occurs through the windows, so that low-E glass, double-layered glass, and vacuum glazing are used to minimize the heat loss. In this paper, an encapsulating process that is a final process in manufacturing the vacuum glazing has been studied, and bonding in a vacuum chamber rather than atmospheric bonding was considered. For the efficiency of the encapsulating process, frit-melting temperature and bonding time were optimized with heater temperature, and the glass preheating temperature was optimized to prevent glass breakage due to thermal stress. Thus the vacuum glass was successfully manufactured based on these results and heat transmission coefficient measured was about $5.7W/m^2K$ which indicates that the internal pressure of the vacuum glazing is $10^{-2}$ torr.

• Conservation Science in Museum
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• v.2
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• pp.35-40
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• 2000

Conservation Science Lab. of the National Museum of Korea recovered Bamboo-plated inkstone case which is used for keeping inkstick, inkstone and inkstone water container by using traditional lacquering and wooden art technology. Texture and construction method of wood, ingredients for lacquering and the method, and the design were analyzed in order to restore the original manufacturing method. Especially, perfect restoration of partially damaged lacquer surface is the most important aspect in restoring Bamboo plated inkstone case, therefore focus was put on investigation of surface lacquering. First, lacquering surface sample was taken off from the object and processed into flake and observed with transmission microscope in order to investigate lacquering method and the pigment in the lacquering surface was analyzed with XRD and SEM-EDS. The result showed that the object was decorated with thin-layered bamboo in the surface which is made of Royal paulownio. and lacquered several times with the mixture of Hematite(Fe₂O₃) and Cinnabar(HgS) in the remaining part.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.115-118
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• 2011

Process characterization of the chemical mechanical polishing (CMP) process for undensified phosphosilicate glass (PSG) film is reported using design of experiments (DOE). DOE has been addressed to experimenters to understand the relationship between input variables and responses of interest in a simple and efficient way. It is typically beneficial for determining the adequate size of experiments with multiple process variables and making statistical inferences for the responses of interests. Equipment controllable parameters to operate the machine include the down force (DF) of the wafer carrier, pressure on the backside of the wafer, table and spindle speed (SS), slurry flow rate, and pad condition. None of them is independent; thus, the interaction between parameters also needs to be indicated to improve process characterization in CMP. In this paper, we have selected the five controllable equipment parameters, such as DF, back pressure (BP), table speed (TS), SS, and slurry flow (SF), most process engineers recommend to characterize the CMP process with respect to material removal rate (RR) and film uniformity as a percentage. The polished material is undensified PSG. PSG is widely used for the plananization in multi-layered metal interconnects. We identify the main effect of DF, BP, and TS on both RR and film uniformity, as expected, by the statistical modeling and analysis on the metrology data acquired from a series of $2^{5-1}$ fractional factorial design with two center points. This revealed the film uniformity of the polished PSG film contains two and three-way interactions. Therefore, one can easily infer that the process control based on better understanding of the process is the key to success in semiconductor manufacturing, typically when the wafer size reaches 300 mm and is continuously scheduled to expand up to 450 mm in or little after 2012.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.75-83
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• 2017

In severe accident conditions of light water reactors, the loss of coolant may cause problems in integrity of zirconium fuel cladding. Under the condition of the loss of coolant, the zirconium fuel cladding can be exposed to high temperature steam and reacted with them by producing of hydrogen, which is caused by the failure in oxidation resistance of zirconium cladding materials during the loss of coolant accident scenarios. In order to avoid these problems, we develop a multi-metallic layered composite (MMLC) fuel cladding which compromises between the neutronic advantages of zirconium-based alloys and the accident-tolerance of non-zirconium-based metallic materials. Cold pilgering process is a common tube manufacturing process, which is complex material forming operation in highly non-steady state, where the materials undergo a long series of deformation resulting in both diameter and thickness reduction. During the cold pilgering process, MMLC claddings need to reduce the outside diameter and wall thickness. However, multi-layers of the tube are expected to occur different deformation processes because each layer has different mechanical properties. To improve the utilization of the pilgering process, 3-dimensional computational analyses have been made using a finite element modeling technique. We also analyze the dimensional change, strain and stress distribution at MMLC tube by considering the behavior of rolls such as stroke rate and feed rate.

• Journal of Korean Association for Spatial Structures
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• v.12 no.4
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• pp.109-118
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• 2012

The large-space single-layer lattice dome is relatively simpler in terms of the arrangement of the various framework members and of the design of the junction than the multi-layered lattice dome, can reduce the numbers and quantity of the framework members, and has the merit of exposing the beauty of the framework as it stands. The single-layer lattice dome, however, requires a stability investigation of the whole structure itself, along with an analysis of the stress of the framework members, because an unstable phenomenon called "buckling" occurs when its weight reaches critical levels. Many researchers have systematically conducted researches on the stability evaluation of the single-layer lattice dome. No construction case of a single-layer lattice dome with a 300-m-long span, however, has yet been reported anywhere in the world. The large-space dome structure is difficult to erect due to the gigantic span and higher ceiling compared with other common buildings, and its construction cost is generally huge. The method of erecting a structure causes major differences in the construction cost and period. Therefore, many researchers have been conducting various researches on the method of erecting such structure. The step-up method developed by these authors can reduce the construction cost and period to a great extent compared with the other general methods, but the application of this method inevitably requires the development of system supports in the center section as well as pre-existing supports in the boundary sections. In this research, the safety during the construction of a single-layer lattice dome with 300-m-long span using pre-existing materials was examined in the aspect of structural strength, and the basic data required for manufacturing the supports in the application of the step-up method developed by these authors during the erection of the roof structure were obtained.

• The Research Journal of the Costume Culture
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• v.17 no.6
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• pp.1112-1128
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• 2009

The purpose of this study was to develop royal costume design with contemporary taste depending on the character of hero, Lee San, and time flow of TV historical drama and research design discrimination and creative expression. As study methods, the literature study using books and theses concerning costume, fine art, culture and history were used for theoretical background and the empirical study method manufacturing actual costume on the basis of literature and relic were used for dress manufacture. The design concept of costume was modern & chic & clean. The costume was designed through straight silhouette, clean & bright colors excluding prime colors, style transformed to permanent straight pleats on the basis of chulik, 100% silk material focusing on high quality and pattern & decoration of the age of Three Kingdoms. As results, the designs of princess' official rob, day dress and chulik, and emperor's official robe, chulik, military dress and chun-dam-bok were developed. The design discrimination depending on social status change. In the period of princess, black, white, silver and blue were used but in the period of emperor, red, gold and black were used. It was expressed through dragon pattern and extended length used in cloth. The design discrimination depending on character change was visualized through color. Although it is not consistent with historical investigation, contemporary fashion design elements were added to royal costume through color contrast of black & white, permanent straight pleats, velcore, wristlet, extended length and layered-look.

• Journal of Technologic Dentistry
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• v.39 no.1
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• pp.43-52
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• 2017

Purpose: Physical and chemical properties of gold is most suitable to be restored of teeth to its original state. Recently zirconia was used instead of gold because of esthetical and intimacy of human body. Because of high strength and high abrasion resistance of zirconia, all zirconia artificial tooth lead to wear the original tooth of opposite site. To preserve this original tooth, zirconia artificial tooth covered with dental ceramic glass was used. When joining the zirconia core and dental ceramic glass, difference of their thermal expansion coefficient and wetting ability is generated the residual stress at interface lead to crack. In order to solve this problem, intermediate layer what is called zir-liner was imported to decrease the residual stress and increase the bonding strength. Methods: In this study, to identify the optimum conditions for manufacturing process, various methods to rough the surface of zirconia core were adopted, and vary the thickness of interlayer, and analyzed bond strength. Results: Bond strength of sanding specimens group showed higher than that of non-sanding specimens group, and once applied intermediate layer with sanding specimens showed highest bond strength with 28 MPa. SEM photomicrographs of zirconia cores fired at $1500^{\circ}C$ showed parallel straight lines in sanding and pockmarked surface in blasting surfaces as abrasion traces. Observation of the destruction section after shear test by SEM were carried out. Liner applied non-sanding group and non-liner applied sanding group all showed interfacial crack. Sandblasting group with non-liner showed remained dental ceramic glass on the surface of zirconia. Sandblasting group with once applied liner showed partially remained liner and dental ceramic glass on the surface of zirconia. XRD analysis revealed that sandblasting group showed higher monoclinic peaks than other specimens group and this result was due to the high collision energy for stress induced phase transformation. Conclusions: A study on the improvement of bonding strength between zirconia and dental ceramic glass steadily carried out for the future to practical use.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.9
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• pp.807-811
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• 2003

We investigated the electrical characterisitics of T $a_2$ $O_{5}$ (tantalum pentoxide) film and Ti-O/T $a_2$ $O_{5}$ film deposited on $Al_2$ $O_3$based substrate. Ta (tantalum) electrode and $Al_2$ $O_3$ substrate was used for the purpose of simplifying the manufacturing process in IPD's (integrated passive devices). Dielectric materials (T $a_2$ $O_{5}$ and Ti-O/T $a_2$ $O_{5}$ films) deposited on Ta/Ti/A $l_2$ $O_3$ were annealed at 700 $^{\circ}C$ for 60 sec. in vacuum. The XRD results showed that as-deposited T $a_2$ $O_{5}$ film possessed amorphous structure, which was transformed to crystallines by rapid thermal heat treatment. We compared the lnJ- $E^{{\frac}{1}{2}}$, C-V, C-F of both as-deposited and annealed dielectric thin films deposited on Ta bottom electrode. From this results, we concluded that the leakage current could be reduced by introducing Ti-O buffer layer and conduction mechanisms of T $a_2$ $O_{5}$ and Ti-O/T $a_2$ $O_{5}$ could be interpreted appropriately by Schottky emission effect.

• Journal of Sensor Science and Technology
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• v.14 no.5
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• pp.322-330
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• 2005

A new type of transducer, piezoelectric floating mass transducer (PFMT) which has advantages of piezoelectric and electromagnetic transducer has been proposed and implemented for the implantable middle ear hearing devices. By the uneven bonding of piezoelectric material to the inner bottom of transducer case, the PFMT can vibrate back-and-forth along the longitudinal axis of the transducer even though the piezoelectric material within the cylindrical case produces only the bilateral expansion and contraction according to the applied electrical signal. To improve efficiency of the PFMT, the multi-layered piezoelectric material has been adapted. The small number of components in the PFMT enables the simple manufacturing and the easy implanting into the middle ear. In order to examine the characteristics of vibration, mechanical modeling and finite element analyses of the proposed transducer have been performed. From the result of theoretical analyses and the measured data from the experiment, it is verified that the implemented PFMT can be used in implantable middle ear hearing devices.