• Journal of IKEEE
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• v.22 no.2
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• pp.302-308
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• 2018

Multi-Layer Sputtering is aim to develop desired thickness thin film multi-layer with different materials. The multi-layer thin film deposition process occupies a relatively large portion in the process time, because the main reason is that it takes much time to move the substrate to be deposited and to make the chamber into a high vacuum state compared to the process time. Most of semiconductor and display industries sputter a single substance in one chamber and move boards through multi-continuous robots to another chamber to sputter other materials. This will inevitably require multiple chambers, vacuum pumps, and multi-contamination robots within the process facility. To solve these problems, this paper proposes a control system for multi-layer thin film sputtering devices that deposit different materials within a single vacuum chamber and is applied in TFT process. The manufacture and experiment of the control system proved its validity.

• Transactions of Materials Processing
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• v.13 no.2
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• pp.129-136
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• 2004

Recently, instead of a matched die forming method requiring a high cost and long delivery term, a multi-point dieless forming method using a pair of matrix type punch array as flexible dies has been developed. Since the conventional multi-point dieless forming method has some disadvantages of difficulty in precise punch control and high-cost of equipment, a new concept of multi-point dieless forming method combined with an elasto-forming method has been suggested in this study. For optimal selection of elastomers, compression tests of rubbers, polyethylene and foams were carried out together with FEM analysis of the deformation behavior during sheet forming process using a rigid punch and elastomers. Compressive strain was concentrated on the upper central area of the elastomer under the punch, and the rubber exhibited higher concentration of the compressive strain than foams. Two-dimensional curved surface was formed successfully by the multi-point elasto-dieless forming method using an optimal combination of rubber and foam materials.

• Textile Coloration and Finishing
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• v.23 no.2
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• pp.107-117
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• 2011

Polyurethane (PU) was synthesized by one-shot process and the PU nanofiber was prepared by electrospinning. In this study, electrospun PU multi-membranes were prepared with various coating thickness ratio of base resin to top resin, where the base resin contains melamine curing agent and acid catalyst and the top resin contains water-repellent agent of fluoro-carbon compounds. The PU nanofiber multi-membranes were analyzed by field-emission scanning electron microscopy, differential scanning calorimeter, breathability, tensile strenth, air permeability and water resistance. The results showed that the PU multi-membrane provided excellent waterproof and moisture permeability.

• Macromolecular Research
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• v.17 no.7
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• pp.491-498
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• 2009

New $\pi$-conjugated multi-branched molecules were synthesized through the Homer-Emmons reaction using alkyl-substituted, 3,4-ethylenedioxythiophene-based, thiophenyl aldehydes and octaethyl benzene-l,2,4,5-tetrayltetrakis(methylene) tetraphosphonate as the core unit; these molecules have all been fully characterized. The two multi-branched conjugated molecules exhibited excellent solubility in common organic solvents and good self-film forming properties. The semiconducting properties of these multi-branched molecules were also evaluated in organic field-effect transistors (OFET). With octyltrichlorosilane (OTS) treatment of the surface of the $SiO_2$ gate insulator, two of the crystalline conjugated molecules, 7 and 8, exhibited carrier mobilities as high as $2.4({\pm}0.5){\times}10^{-3}$ and $1.3({\pm}0.5){\times}10^{-3}cm^2V^{-1}s^{-1}$, respectively. The mobility enhancement of OFET by light irradiation ($\lambda$ = 436 nm) supported the promising photo-controlled switching behavior for the drain current of the device.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.3026-3034
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• 2021

Multi-target X-ray tube is a new type X-ray source, and can be applied in many fields such as sensitive X-ray fluorescence analysis and medical imaging. In this work, we report an electric field modulation multi-target X-ray tube, which contains four targets (Cr, Ni, Au, Mo) coated on a Beryllium (Be) window. A four-valve electric field deflector was developed to deflect the electron beam to bombard the corresponding targets. Particle dynamics analysis software was employed to simulate the particle tracking of electron beam. The results show that the 30 keV electron beam could get a 6.7 mm displacement on the target plane by 10⁵ V/m electric field. The focus areas are about 2 mm × 5 mm and 4 mm × 2.5 mm after deflection in two directions. Thermal behavior calculated by ANSYS shows that the designed target assembly could withstand a 10 W continuous power. The optimum target thicknesses and emission spectra were obtained by Geant4 when the thickness of Be window was 300 mm and the electron beam incident angle was 0.141 rad. The results indicate that this multi-target X-ray tube could provide different X-ray sources effectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.319-319
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• 2013

Even though the fabrication methods of metal oxide based thin film capacitor have been well established such as RF sputtering, Sol-gel, metal organic chemical vapor deposition (MOCVD), ion beam assisted deposition (IBAD) and pulsed laser deposition (PLD), an applicable capacitor of printed circuit board (PCB) has not realized yet by these methods. Barium Strontium Titanate (BST) and other high-k ceramic oxides are important materials used in integrated passive devices, multi-chip modules (MCM), high-density interconnect, and chip-scale packaging. Thin film multi-layer technology is strongly demanded for having high capacitance (120 nF/$mm^2$). In this study, we suggest novel multi-layer thin film capacitor design and fabrication technology utilized by plasma assisted deposition and photolithography processes. Ba0.6Sr0.4TiO3 (BST) was used for the dielectric material since it has high dielectric constant and low dielectric loss. 5-layered BST and Pt thin films with multi-layer sandwich structures were formed on Pt/Ti/$SiO_2$/Si substrate by RF-magnetron sputtering and DC-sputtering. Pt electrodes and BST layers were patterned to reveal internal electrodes by photolithography. SiO2 passivation layer was deposited by plasma-enhanced chemical vapor deposition (PE-CVD). The passivation layer plays an important role to prevent short connection between the electrodes. It was patterned to create holes for the connection between internal electrodes and external electrodes by reactive-ion etching (RIE). External contact pads were formed by Pt electrodes. The microstructure and dielectric characteristics of the capacitors were investigated by scanning electron microscopy (SEM) and impedance analyzer, respectively. In conclusion, the 0402 sized thin film multi-layer capacitors have been demonstrated, which have capacitance of 10 nF. They are expected to be used for decoupling purpose and have been fabricated with high yield.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.417-417
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• 2012

For desired optical properties of QDs, it is very important to reduce the presence of defects on their surfaces. Passivation of surface defects using larger band gap materials is the most effective way. Some groups successfully synthesized Cd based multi-shell structured quantum dots and improved its optical properties. However, its productivity has limit because of the amounts of glass ware and space. In this research, we try to synthesize Cd based multi-shell structured nanocrystal quantum dots to overcome demerits of conventional batch synthetic method. This reactor composed pump, SUS reaction part (3.2 mm stainless steel and furnace) and batch mixer. We successively synthesized CdSe/CdS/ZnS quantum dot at this reactor in one step.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.81-87
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• 2006

This paper describes a method for extracting surfaces from multi-material CT (Computed Tomography) data. Most contouring methods such as Marching Cubes algorithm assume that CT data are composed of only two materials. Some extended methods such as [3, 6] can extract surfaces from the multi-material (non-manifold) implicit representation. However, these methods are not directly applicable to CT data that are composed of three or more materials. There are two major problems that arise from fundamentals of CT. The first problem is that we have to use n(n-1)/2 threshold values for CT data contains n materials and select appropriately one threshold value for each boundary area. The second is that we cannot reconstruct only from CT data in which area three or more materials are adjacent each other. In this paper, we propose a method to solve the problems by using image analysis and demonstrate the effectiveness of the method with application examples construct polygon models from CT data of machine parts.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.207-210
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• 2009

According to the recent demand for materials for use in various displays and solid state lightings, new phosphors with improved performance have been pursued consistently. Multi objective genetic algorithm assisted combinatorial material search (MOGACMS) strategies have been applied to various multi-compositional inorganic systems to search for new phosphors and to optimize the properties of phosphors.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.207-207
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• 2000

Multi- and single-wall carbon nanotubes are promising new carbon materials in nano-electronics, field-emitters, CRT-displays, hydrogen storage materials, biomedical tracers and so forth. The present talk will deal with a high-yield synthesis on quasi-aligned multi-wall carbon nanotubes via a chemical vapor deposition technique. I will also talk about a possible growth mechanism on single-wall carbon nanotubes based on newly obtained experimental results.