• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.366-369
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• 2003

The vertical fountain plating system with the point contact has been used in semiconductor industry. But the plating shape in the opening of photoresist becomes gradated shape, because bubbles from the wafer surface are difficult to escape from the deep openings, vias. So, we designed the tilted electrode ring contact to get uniform bump height on all over the wafer and evaluated the film uniformity by SEM and $\alpha$-step. A photoresist was coated to a thickness of $60{\mu}m$ and vias were patterned by a contact aligner After via opening, solder layer was electroplated using the fountain plating system and the tilted electrode ring contact system. In $\alpha$-step measurement, film uniformities in the fountain plating system and the tilted electrode ring contact system were ${\pm}16%,\;{\pm}3.7%$ respectively. In this study, we could get high uniformity bumps by the tilted electrode ring contact system. So, tilted electrode ring contact system is expected to improve workability and yield in module process.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.3
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• pp.55-74
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• 1991

The purpose of this study was to investigate the influence of early functional load around osseointegrated titanium implants. 24 titanium plasma spray coated implants (ITI HS-type) were placed into the previously extracted site in the mandible of six adult dogs. The implants were divided into three groups : the control group was the implants without abutment during the experimental period; the experimental group I was loaded by connecting the contoured abutment after 6 weeks of healing; the experimental group II was loaded after 12 weeks of healing: and the mandibular second premolar and surrounding tissues were selected for natural tooth group to compare the implanted group. All dogs were injected intravenously tetracycline, alizarin red S, and calcein for bone labeling. After the experimental period of 18 weeks, the dogs were sacrificed and longitudinal sections of the bone-implant interface were cut and observed using light microscope, scanning electron microscope, and fluorescence microscope. The results of the study were as follows: 1. Light and scanning electron microscopically, all implant surfaces were well contact with bone tissue at the cortical layer, but some areas of cancellous bone were not contact directly. 2. Fluorescence microscopically, number and size of the new secondary osteons around the implant were increased than those of the natural tooth. 3. Fluorescence microscopically, linear and concentrical fluorescence was observed at or near the surface of all implants, and the bone formation and remodeling of the implants loaded after 6 week of healing were great, and unloaded implants were worst. 4. Fluorescence microscopically, endosteal bone formation was greater than periosteal bone formation at or near the implants. 5. Fluorescence microscopically, number and size of linear and concentric fluorescence was increased at the lingual side than the buccal side of the loaded implants. The result of the study indicate the possibility of the early load to the implant via a prosthesis.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.539-541
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• 2015

We present a new tool for studying the spectral energy distributions (SEDs) and color-magnitude diagrams (CMDs) of galaxies and star clusters, BINARY STAR TO FIT (BS2fit). A key feature of this tool is that it takes the effects of binaries, stellar rotation and star formation history into account. It can be used to determine many parameters, including distance, extinction, binary fraction, rotational star fraction, and star formation history. Because more factors are included than in previous tools, BS2fit can potentially give new insight into the properties of galaxies and clusters. One can contact the authors for cooperation and helps via.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.291-291
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• 2013

The wettability of TiO2 layers is controlled by forming highly ordered arrays of nanocones using nanopatterning, based on self-assembly and dry etching. Nanopatterning of TiO2 layers is achieved via formation of self-assembled monolayers of SiO2 spheres fabricated using the Langmuir-Blodgett technique, followed by dry etching. Compared to a thin film TiO2 layer, the nanopatterned TiO2 samples show a smaller static water contact angle, where the water contact angle decreases as the etching time increases, which is attributed to the Wenzel equation. When TiO2 layers are coated by 1H,1H,2H,2H-perfluorooctyltrichlorosilane, we observed the opposite behavior, exhibiting superhydrophobicity (up to contact angle of $155^{\circ}$) on the nanopatterned TiO2 layers. Self-assembled nanopatterning of the TiO2 layer may provide an advanced method for producing multifunctional transparent layers with self-cleaning properties.

• Advances in nano research
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• v.16 no.3
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• pp.217-229
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• 2024

This paper presents results of visual analysis of cracks formation and propagation of concretes made of quaternary binders (QBC). A composition of the two most commonly used mineral additives, i.e. fly ash (FA) and silica fume (SF) in combination with nanosilica (nS), has been proposed as a partial replacement of the cement. The principal objective of the present study is to achieve information about the effect of simultaneous incorporation of three pozzolans as partial replacement to the OPC on the fracture processes in concretes made from quaternary binders (QBC). The modern and precise non-contact measurement method (NCMM) via digital image correlation (DIC) technique was used, during the studies. In the course of experiments it was established that the substitution of OPC with three pozzolans including the nanoadditive in FA+SF+nS FA+SF+nS combination causes a clear change of brittleness and behavior during fractures in QBCs. It was found that the shape of cracks in unmodified concrete was quasi-linear. Substitution of the binder by SCMs resulted in a slight heterogeneity of the structure of the QBC, including only SF and nS, and clear heterogeneity for concretes with the FA additive. In addition, as content of FA rises throughout each of QBC series, material becomes more ductile and shows less brittle failure. It means that an increase in the FA content in the concrete mix causes a significant change in fracture process in this composite in comparison to concrete with the addition of silica modifiers only.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.1
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• pp.33-38
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• 2001

We investigate the via-size dependance of as-electroplated- and reflow-bump shapes for realizing both high-density and high-aspect ratio of solder bump. The solder bump is fabricated by subsequent processes as follows. After sputtering a TiW/Al electrode on a 5-inch Si-wafer, a thick photoresist for via formation it obtained by multiple-codling method and then vias with various diameters are defined by a conventional photolithography technique using a contact alinger with an I-line source. After via formation the under ball metallurgy (UBM) structure with Ti-adhesion and Cu-seed layers is sputtered on a sample. Cu-layer and Sn/pb-layer with a competition ratio of 6 to 4 are electroplated by a selective electroplating method. The reflow-bump diameters at bottom are unchanged, compared with as-electroplated diameters. As-electroplated- and reflow-bump shapes, however, depend significantly on the via size. The heights of as-electroplated and reflow bumps increase with the larger cia, while the aspect ratio of bump decreases. The nearest bumps may be touched by decreasing the bump pitch in order to obtain high-density bump. The touching between the nearest bumps occurs during the overplating procedure rather than the reflowing procedure because the mushroom diameter formed by overplating is larger than the reflow-bump diameter. The arrangement as zig-zag rows can be effective for realizing the flip-chip-interconnect bump with both high-density and high-aspect ratio.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.09a
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• pp.261-278
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• 2003

Concepts.Wafer-Level Chip-Scale Concept with Handling Substrate.Low Accuracy Placement Layout with Isolation Trench.Possible Pitch of Interconnections down to $10{\mu}{\textrm}{m}$ (Sn-Grains).Wafer-to-Wafer Equipment Adjustment Accuracy meets this Request of Alignment Accuracy (+/-1.5 ${\mu}{\textrm}{m}$).Adjustment Accuracy of High-Speed Chip-to-Wafer Placement Equipment starts to meet this request.Face-to-Face Modular / SLID with Flipped Device Orientation.interchip Via / SLID with Non-Flipped Orientation SLID Technology Features.Demonstration with Copper / Tin-Alloy (SLID) and W-InterChip Vias (ICV).Combination of reliable processes for advanced concept - Filling of vias with W as standard wafer process sequence.No plug filling on stack level necessary.Simultanious formation of electrical and mechanical connection.No need for underfiller: large area contacts replace underfiller.Cu / Sn SLID layers $\leq$ $10{\mu}{\textrm}{m}$ in total are possible Electrical Results.Measurements of Three Layer Stacks on Daisy Chains with 240 Elements.2.5 Ohms per Chain Element.Contribution of Soldering Metal only in the Range of Milliohms.Soldering Contact Resistance ($0.43\Omega$) dominated by Contact Resistance of Barrier and Seed Layer.Tungsten Pin Contribution in the Range of 1 Ohm

• Current Photovoltaic Research
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• v.3 no.3
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• pp.85-90
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• 2015

Two-step processes for preparing $Cu(In,Ga)Se_2$ absorber layers consist of precursor layer formation and subsequent annealing in a Se-containing atmosphere. Among the various deposition methods for precursor layer, the nonvacuum (wet) processes have been spotlighted as alternatives to vacuum-based methods due to their potential to realize low-cost, scalable PV devices. However, due to its porous nature, the precursor layer deposited on Mo substrate by nonvacuum methods often suffers from thick $MoSe_2$ formation during selenization under a high Se vapor pressure. On the contrary, selenization under a low Se pressure to avoid $MoSe_2$ formation typically leads to low crystal quality of absorber films. Although TiN has been reported as a diffusion barrier against Se, the additional sputtering to deposit TiN layer may induce the complexity of fabrication process and nullify the advantages of nonvacuum deposition of absorber film. In this work, Mo oxide layers via thermal oxidation of Mo substrate have been explored as an alternative diffusion barrier. The morphology and phase evolution was examined as a function of oxidation temperature. The resulting Mo/Mo oxides double layers were employed as a back contact electrode for $CuInSe_2$ solar cells and were found to effectively suppress the formation of $MoSe_2$ layer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.6
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• pp.345-351
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• 2016

Objectives: This study compared the impact of implant surface treatment on the stability and osseointegration of implants in dog mandibles. Materials and Methods: Six adult dogs received a total of 48 implants that were prepared using four different surface treatments; resorbable blast media (RBM), hydroxyapatite (HA), hydrothermal-treated HA, and sand blasting and acid etching (SLA). Implants were installed, and dogs were separated into 2- and 4-week groups. Implant stability was evaluated via Periotest M, Osstell Mentor, and removal torque analyzers. A histomorphometric analysis was also performed. Results: The stability evaluation showed that all groups generally had satisfactory values. The histomorphometric evaluation via a light microscope revealed that the HA surface implant group had the highest ratio of new bone formation on the entire fixture. The hydrothermal-treated HA surface implant group showed a high ratio of bone-to-implant contact in the upper half of the implant area. Conclusion: The hydrothermal-treated HA implant improved the bone-to-implant contact ratio on the upper fixture, which increased the implant stability.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.149-154
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• 2013

In this study, the simple preparation of poly(sodium 4-styrenesulfonate) (PSS)-patterned substrate via a selective ion irradiation was investigated to manipulate cell adhesion. PSS thin films spin-coated onto the hydrophobic polystyrene (PS) was patterned through masked 150 keV proton irradiation followed by developing with deionized water. The characteristics of the resulting PSS-patterned surfaces were investigated by using microscope, surface profiler, FT-IR, XPS, and contact angle analyzer. These analytical results revealed that the resolved $100{\mu}m$ PSS patterns were formed on the hydrophobic PS surface above the fluence of $1{\times}10^{15}ions\;cm^{-2}$ and the chemical structure, composition, and wettability of the PSS patterns were dependant on a fluence. Moreover, the results of the in-vitro cell culture and proliferation assay exhibited that H1299 cells preferentially adhered and proliferated onto the more hydrophilic PSS part of the PSS-patterned PS and the well-aligned cell patterns was formed on the PSS-patterned PS particularly at the fluence of $1{\times}10^{15}ions\;cm^{-2}$.