• Title/Summary/Keyword: Electro-chemical process

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Preparation of Silica Nanoparticles via Recycling of Silicon Sludge from Semiconductor Dicing Process and Electro-responsive Smart Fluid Application (반도체 다이싱 공정에서 발생하는 실리콘 슬러지를 재활용한 실리카 나노입자의 제조 및 전기감응형 유체로의 응용)

  • Yeon-Ryong Chu;Suk Jekal;Jiwon Kim;Ha-Yeong Kim;Chan-Gyo Kim;Minki Sa;Hyung Sub Sim;Chang-Min Yoon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.31 no.3
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    • pp.15-25
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    • 2023
  • In this study, silicon sludge from semiconductor dicing process is recycled to fabricate silica nanoparticles, which are applied as dispersing materials for electro-responsive (ER) smart fluid. In specific, metal impurities are removed from silicon sludge by acid washing to obtain the high-purity silicon powder. And then, silica nanoparticles are synthesized by facile hydrothermal method employing the silicon powder as reactant material. To control the size of silica nanoparticles, the reaction time of hydrothermal method is varied as 8, 15, 20, and 30 hours are applied to control the size of silica nanoparticles. Sizes of silica nanoparticles are increased proportionally to the reaction time owing to the increased numbers of hydrolysis and condensation reactions. As-synthesized silica nanoparticles are prepared as electro-responsive smart fluids by dispersing into silicon oil. Silica nanoparticles synthesized by 30 hours of hydrothermal reaction (SiO2-H30) exhibit the highest shear stress of 21.4 Pa under an applied electric field strength of 3.0kV mm-1. Such enhancement in ER performance of SiO2-H30 among various silica nanoparticles are attribute to the reinforcing effect originated from the mixed particle size, which allowing the formation of rigid chain-like structures. Accordingly, this study successfully propose a recycling method of silicon sludge to synthesize silica nanoparticles and their derived ER fluids, which may suggest new possibility to ESG management emphasizing the eco-friendliness.

Fabrication of $CeO_2$ Buffer Layer Using MOD Process

  • Kim, Young-Kuk;Yoo, Jai-Moo;Chung, Kook-Chae;Ko, Jae-Woong
    • Progress in Superconductivity and Cryogenics
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    • v.8 no.4
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    • pp.19-21
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    • 2006
  • Biaxially textured Ni was fabricated by electrodeposition process and delaminated from the biaxially textured cathode surface for further buffer layer deposition process. Those electrode posited Ni substrates showed well-developed biaxial texture and smooth surface. In order to improve the thermal stability of Ni substrates, Mn was alloyed by adding Mn precursor into the electrodeposition bath. Subsequently, $CeO_2$ buffer layers are deposited by MOD process to prevent interfacial reaction between superconductor and substrates. In particular, Bismuth oxide was added to $CeO_2$ to realize lower temperature processing of buffer layers. The microstructure and texture development of each layers have been investigated. Preliminary results shows that all electro/chemical process can be a candidate for cost effective route to YBCO coated conductor.

Technical Issue and Development Status of Molten Carbonate Fuel Cell (용융탄산염형 연료전지의 개발현황 및 기술과제)

  • Kim, Gwi-Yeol;Yun, Mun-Soo
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.251-254
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    • 1991
  • Fuel cell generating technology is to produce electricity directly through electro-chemical process by combining oxygen from the air with the hydrogen obtained in processing fuels such as natural gas, methanol, coal and others. The objectives of this study are to investigate the status of Molten Carbonate Fuel cell technologies.

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Bacterial Community Analysis during Composting of Garbage using Denaturing Gradient Gel Electro-phoresis (Denaturing Gradient Gel Electrophoresis를 이용한 음식물 쓰레기 퇴비화 세균 군집 분석)

  • Ryu Hee Wook;Cho Kyung-Suk
    • Microbiology and Biotechnology Letters
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    • v.33 no.3
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    • pp.226-230
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    • 2005
  • The microbial community during composting of gargage was analyzed using 16S rDNA PCR - DGCE (denaturing gradient gel electrophoresis). Pseudomonas spp. was found throughout the process, and thermophilic Bacillus spp. was dominated at the thermophilic stage. Six thermophilic bacteria were isolated and identified as B. caldoxylolyticus, B. thermoalkalophilus, and B. thermodenitrificans.

Liquid Crystal Alignment Effect on Polyimide Surface by Ion-beam Irradiation (이온빔을 이용한 폴리이미드 표면의 액정배향효과)

  • Park, Hong-Gyu;Oh, Byeong-Yun;Kim, Young-Hwan;Kim, Byoung-Yong;Han, Jeong-Min;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.330-330
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    • 2008
  • It is widely investigated to liquid crystal (LC) alignment using non-contact alignment method such as ion-beam (IB) irradiation, UV alignment, and oblique deposition. Because conventional rubbing method has some drawbacks. These include defects from dust and electrostatic charges and rubbing scratch during rubbing process. In addition, rubbing method needs additional process to remove these defects. Therefore rubbing-free methods like ion-beam irradiation are strongly required. We studied LC alignment effect on poly imide surface by IB irradiation and electro-optical (EO) characteristics of twisted nematic liquid crystal display (TN-LCD). In this experiment, a good uniform alignment of the nematic liquid crystal (NLC) with the ion-beam exposure on the polyimide (PI) (SE-150 from Nissan Chemical) surface was observed. We also achieved low pretilt angle as a function of ion-beam irradiation intensity. In addition, it can be obtained the good EO properties of the IB-aligned TN-LCD on PI surface. Some other experiments results and discussion will be included in the poster.

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ELECTROSPINNING OF ANTIMONY DOPED TIN OXIDE NANOPARTICLE DISPERSION FOR TRANSPARENT AND CONDUCTIVE FILMS

  • YOUNG-SANG CHO;MINHO HAN;SEUNG HEE WOO
    • Archives of Metallurgy and Materials
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    • v.65 no.4
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    • pp.1345-1350
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    • 2020
  • Stable dispersion of antimony-doped tin oxide nano-powder was prepared by wet attrition process by comminuting aggregated ATO nano-powder using the titanate coupling agent as a dispersant to form the chemisorbed layer on the particle surface. The feed solution of the ATO dispersion and PVP was prepared for electro-spun fibers on the glass substrate. The surface resistance of the fibrous ATO film after electrospinning for 30 minutes was in the order of 105 Ω/□, which is sufficient for anti-static coating. The optical transmittance of ATO fibers was confirmed by measuring the visible light transmittance.

The Active Dissolved Wafer Process (ADWP) for Integrating single Crystal Si MEMS with CMOS Circuits

  • Karl J. Ma;Yogesh B. Glanchandani;Khalil Najafi
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.2 no.4
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    • pp.273-279
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    • 2002
  • This paper presents a fabrication technology for the integration of single crystal Si microstructures with on-chip circuitry. It is a dissolved wafer technique that combines an electro-chemical etch-stop for the protection of circuitry with an impurity-based etch-stop for the microstructures, both of which are defined in an n-epi layer on a p-type Si wafer. A CMOS op. amp. has been integrated with $p^{++}$ Si accelerometers using this process. It has a gain of 68 dB and an output swing within 0.2 V of its power supplies, unaffected by the wafer dissolution. The accelerometers have $3{\;}\mu\textrm{m}$ thick suspension beams and $15{\;}\mu\textrm{m}$ thick proof masses. The structural and electrical integrity of the fabricated devices demonstrates the success of the fabrication process. A variety of lead transfer methods are shown, and process details are discussed.

The Alignment of Liquid Crystals on the Film Surfaces of Soluble Aromatic Polyimides Bearing t-Butylphenyl and Trimethylsilylphenyl Side Groups

  • Hahm, Suk-Gyu;Jin, Kyeong-Sik;Park, Sam-Dae;Ree, Moon-Hor;Kim, Hyung-Sun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Macromolecular Research
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    • v.17 no.12
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    • pp.976-986
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    • 2009
  • With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.

A Study on DOE Method to Optimize the Process Parameters for Cu CMP (구리 CMP 공정변수 최적화를 위한 실험계획법(DOE) 연구)

  • Choi, Min-Ho;Kim, Nam-Hoon;Kim, Sang-Yong;Chang, Eui-Goo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.1
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    • pp.24-29
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    • 2005
  • Chemical mechanical polishing (CMP) has been widely accepted for the global planarization of multi-layer structures in semiconductor manufacturing. Copper has been the candidate metallization material for ultra-large scale integrated circuits (ULSIs), owing to its excellent electro-migration resistance and low electrical resistance. However, it still has various problems in copper CMP process. Thus, it is important to understand the effect of the process variables such as turntable speed, head speed, down force and back pressure are very important parameters that must be carefully formulated in order to achieve desired the removal rates and non-uniformity. Using a design of experiment (DOE) approach, this study was performed investigating the main effect of the variables and the interaction between the various parameters during CMP. A better understanding of the interaction behavior between the various parameters and the effect on removal rate, non-uniformity and ETC (edge to center) is achieved by using the statistical analysis techniques. In the experimental tests, the optimum parameters which were derived from the statistical analysis could be found for higher removal rate and lower non-uniformity through the above DOE results.