• 제목/요약/키워드: Thin Wire

검색결과 217건 처리시간 0.023초

TSOP(Thin Small Outline Package) 열변형 개선을 위한 전산모사 분석 (Numerical Analysis for Thermal-deformation Improvement in TSOP(Thin Small Outline Package) by Anti-deflection Adhesives)

  • 김상우;이해중;이효수
    • 마이크로전자및패키징학회지
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    • 제20권3호
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    • pp.31-35
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    • 2013
  • TSOP(Thin Small Outline Package)는 가전제품, 자동차, 모바일, 데스크톱 PC등을 위한 저렴한 비용의 패키지로, 리드 프레임을 사용하는 IC패키지이다. TSOP는 BGA와 flip-chip CSP에 비해 우수한 성능은 아니지만, 저렴한 가격 때문에 많은 분야에 널리 사용되고 있습니다. 그러나, TSOP 패키지에서 몰딩공정 할 때 리드프레임의 열적 처짐 현상이 빈번하게 일어나고, 반도체 다이와 패드 사이의 Au 와이어 떨어짐 현상이 이슈가 되고 있다. 이러한 문제점을 해결하기 위해서는 리드프레임의 구조를 개선하고 낮은 CTE를 갖는 재료로 대체해야 한다. 본 연구에서는 열적 안정성을 갖도록 리드프레임 구조 개선을 위해 수치해석적 방법으로 진행하였다. TSOP 패키지에서 리드프레임의 열적 처짐은 반도체와 다이 사이의 거리(198 um~366 um)에서 안티-디플렉션의 위치에 따라 시뮬레이션을 진행하였다. 안티-디플렉션으로 TSOP 패키지의 열적 처짐은 확실히 개선되는 것을 확인 했다. 안티-디플렉션의 위치가 inside(198 um)일 때 30.738 um 처짐을 보였다. 이러한 결과는 리드프레임의 열적 팽창을 제한하는데 안티-디플렉션이 기여하고 있기 때문이다. 그러므로 리드프레임 패키지에 안티-디플렉션을 적용하게 되면 낮은 CTE를 갖는 재료로 대체하지 않아도 열적 처짐을 향상시킬 수 있음을 기대할 수 있다.

단결정 실리콘 태양전지의 광 포획 개선을 위한 Ag Nano-Dots 및 질화막 적용 연구 (A Study on Application of Ag Nano-Dots and Silicon Nitride Film for Improving the Light Trapping in Mono-crystalline Silicon Solar Cell)

  • 최정호;노시철;서화일
    • 반도체디스플레이기술학회지
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    • 제18권4호
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    • pp.12-17
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    • 2019
  • In this study, the Ag nano-dots structure and silicon nitride film were applied to the textured wafer surface to improve the light trapping effect of mono-crystalline silicon solar cell. Ag nano-dots structure was formed by performing a heat treatment for 30 minutes at 650℃ after the deposition of 10nm Ag thin film. Ag thin film deposition was performed using a thermal evaporator. The silicon nitride film was deposited by a Hot-wire chemical vapor deposition. The effect of light trapping was compared and analyzed through light reflectance measurements. Experimental results showed that the reflectivity increased by 0.5 ~ 1% under all nitride thickness conditions when Ag nano-dots structure was formed before nitride film deposition. In addition, when the Ag nano-dots structure is formed after deposition of the silicon nitride film, the reflectance is increased in the nitride film condition of 70 nm or more. When the HF treatment was performed for 60 seconds to improve the Ag nano-dot structure, the overall reflectance was improved, and the reflectance was 0.15% lower than that of the silicon nitride film-only sample at 90 nm silicon nitride film condition.

정찰포탄용 접지선 구조를 이용한 평판형 무지향성 마이크로스트립 안테나 (Low-Profile Omni-Directional Microstrip Antenna Using Wired Ground Structure For Observation Munition)

  • 표성민
    • 전기전자학회논문지
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    • 제23권3호
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    • pp.1112-1115
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    • 2019
  • 본 논문에서는 정찰포탄의 활공날개에 적용할 수 있는 새로운 평판형 무지향성 마이크로스트립 안테나를 제안하였다. 제안한 안테나는 무지향성 방사패턴을 얻기 위하여 얇은 기판에 7개의 정육각형 공진기를 준원형을 배열한 구조를 가지고 있다. 안테나 기판의 하단부에 그물망 형태로 이루어진 접지선 구조를 적용하여, 안테나의 공진주파수와 임피던스 대역폭에 관한 연구를 수행하였다. 그물망 형태의 접지선 구조의 유효성을 검증하기 위하여, 접지선의 선폭을 이론적으로 분석하여 상대 대역폭, Q-factor 및 안테나 이득을 만족시키기 위한 최적화 기법을 수행하였다. 제안한 안테나는 모의실험결과와 유사한 측정결과를 보임으로써, 무지향성 방사패턴이 잘 형성됨을 시연하였다. 마지막으로 제작한 안테나 시제품은 5.77 GHz를 중심으로 약 5.65%의 상대대역폭에 해당하는 326 MHz의 동작대역폭을 확인하였으며, 공진주파수 5.84 GHz에서 5.49 dBi의 안테나 이득을 확인하였다.

다이아몬드 분말상에 무전해 Ni-B 도금을 위한 계면활성제의 영향 (Effect of Surfactant in Electroless Ni-B Plating for Coating on the Diamond Powder)

  • 양창열;유시영;문환균;이정호;유봉영
    • 한국표면공학회지
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    • 제50권3호
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    • pp.177-182
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    • 2017
  • The properties of electroless Ni-B thin film on diamond powder with different parameters (temperature, pH, surfactant etc.) were studied. The surface morphology, structure and composition distribution of the Ni-B film were observed by field effect scanning electron microscope (FE-SEM), energy-dispersive spectrometer (EDS), X-ray diffraction (XRD) and Auger electron spectroscopy (AES). The growth rate of Ni-B film was increased with increase of bath temperature. The B content in Ni-B film was reduced with increase of bath pH. As a result the structure of Ni-B film was changed from amorphous to crystalline structure. The PVP in solution plays multi-functional roles as a dispersant and a stabilizer. The Ni-B film deposited with adding 0.1 mM-PVP was strongly introduced an amorphous structure with higher B content (25 at.%). Also the crystallite size of Ni-B film was reduced from 12.7 nm to 5.4 nm.

Amalgam 부식산물의 정성분석에 관한 연구 (A QUANTITATIVE ANALYSIS OF THE IN VIVO AMALGAM CORROSION PRODUCTS)

  • 임병목;엄정문
    • Restorative Dentistry and Endodontics
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    • 제16권2호
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    • pp.1-17
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    • 1991
  • The purpose of this study was to analyze the in vivo amalgam corrosion products qualitatively. 30 molars with large, intact amalgam restorations were selected. All the restorations were more than 5 years old. Twenty of the removed amalgams were embedded in acrylic resin block. The exposed surfaces of fifteen embedded amalgams were polished by amalgam polishing kit, and the rest were observed without polishing. The remaining 10 amalgams were fractured centrally and perpendiculary to the occlusal surface with a wire-cutter. After all specimens were cleaned ultrasonically in distilled water, each surface was examined under S.E.M. and E.D.A.X. (Energy Dispersive Micro X-ray Analyzer) to determine the morphology and chemical nature of the corrosion products. The following results were obtained: 1. The surfaces of the unpolished amalgam restorations were covered with thin amorphous layer of Sn-Ca-P-S complex with numerous cracks. 2. In the conventional amalgams, the major corrosion products were Sn-Cl phases however, tin oxide phases were also observed. 3. Only tin oxide phase was identified in the high copper amalgam, but it was less frequently observed than in the conventional amalgam. 4. It was easier to observe the corrosion product morphology in the fractured surfaces than in the polished ones. The morphologies of the corrosion product crystals looked like a stack of slightly bended plates in the Sn-Cl phases and polyhedra or polygonal prisms in the tin oxide phases.

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외부전기장 적용 섬유상 에어필터의 절연 전극 사용에 따른 여과특성 (Filtration Performance of Fibrous Air Filter under External Electric Field using Insulated Electrodes)

  • 지성미;손종렬;박현설
    • 한국대기환경학회지
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    • 제28권6호
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    • pp.675-687
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    • 2012
  • Applying an external electric field across air filter media is one of methods to improve the filtration performance. Metal wire meshes have been commonly used as electrodes situated on both sides of a thick filter pad. For a thin filter medium a short circuit, known as the biggest drawback for applying an external electric field to air filter, can occur at the closest point between electrodes. In this study several types of insulated meshes were prepared by coating #50 meshes with a dielectric material, Nylon 66, and the filtration property of air filter was evaluated at the presence of external electric field using those insulated meshes as electrodes and compared with that of filters using bared meshes. The collection efficiency of tested filter was increased from 78% to 95% for singly charged 100 nm particles by application of external electric field. As a result, there was no significant difference in collection efficiency between filters with insulated and bared electrodes. Similar results could be also seen from the tests using polydisperse particles. Finally, through this study, we found that the insulation of mesh electrodes doesn't affect the filtration performance of fibrous air filter under external electric field.

단일액상원료를 사용하는 MOCVD법에 의한 YBa$_2Cu_3O_x$ 박막 제조에 관한 연구 (Preparation of YBa$_2Cu_#O_x$ films by MOCVD using single liquid solution source)

  • 김보련;이희균;홍계원;지영아;신형식
    • 한국초전도학회:학술대회논문집
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    • 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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    • pp.129-132
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    • 1999
  • A new single solution source MOCVD technique for the deposition of YBCO film has been developed, using a ultrasonic atomizer to feed the precursors into an evaporation zone. This method being investigated as a basis for future long wire fabrication, for example the electric power use, the magnatic applications, etc.. YBCO films were prepared on MgO(100) substrate, using mixture of Y, Ba, and Cu ${\beta}$ -diketonate chelate was dissolve in tetrahydrofuran as a solution sources. X-ray diffraction measurement indicated that the thin film grew epitaxially with the c-axis orientation perpandicular to the surface of the surface.

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KRISO 300K VLCC 이중모형선의 유동특성에 대한 풍동실험 연구 (Wind Tunnel Study on Flow Characteristics around KRISO 300K VLCC Double-body Model)

  • 김학록;이상준
    • 대한조선학회논문집
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    • 제36권3호
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    • pp.15-21
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    • 1999
  • KRISO 300K VLCC 이중모형선 주위의 유동특성을 풍동실험을 통해 연구하였다. 선체 선미 주위유동과 후류유동의 평균속도 성분, 난류강도, 레이놀즈 전단응력 및 난류 운동에너지 분포를 열선풍속계를 이용하여 측정하였다. 실험은 선미와 후류의 횡단면에서 수행하였으며, 선체 표면에서의 유동 패턴을 정성적으로 조사하기 위하여 유막법을 이용한 유동가시화도 수행하였다. 선미와 근접 후류영역은 매우 복잡한 3차원의 유동특성을 가지고 있으며, 특히 종방향 와류영역에서 고리 모양의 후류 구조를 볼 수 있었다. 그리고 중앙평행부에서의 얇은 경계층은 선미 영역을 지나며 점차 두꺼워지고 복잡한 3차원 난류후류로 발전하였다.

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인지질(DOPC)과 지방산(8A5H)의 혼합 LB막의 광이성질화 현상과 전기화학적 특성 (Electrochemical Properties and Photoisomerization of DOPC-8A5H Mixture Langmuir-Blogett Films)

  • 박근호;최성현;김남석;김덕술
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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    • pp.874-877
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    • 2004
  • We carried out this subject to observe electrochemical properties of 1,2-dioleoyl-sn- glycero-3-phosphocholine(DOPC) mixed with fatty acid containing azobenzene group by using cyclic voltammetry with a three-electrode system, An Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode in $NaClO_4$ solution. We investigated the photoisomerization and electrochemical property of the organic ultra thin film of fatty acid containing azobenzene was prepared on the hydrophilic ITO(idium tin oxide) glass plate by LB method. As a result, the absorption spectra of BASH and DOPC of mixture LB films was induced to photoisomerization by alternating irradiation of ultraviolet and visible light. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate were 50, 100, 150 and 200 mV/s. As a results, LB films of BASH-DMPC appeared reversible process caused by the reduction-oxidation current from the cyclic voltammogram.

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Flows over Concave Surfaces: Development of Pre-set Wavelength Görtler Vortices

  • Winoto, S.H.;Tandiono, Tandiono;Shah, D.A.;Mitsudharmadi, H.
    • International Journal of Fluid Machinery and Systems
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    • 제1권1호
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    • pp.10-23
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    • 2008
  • The development of pre-set wavelength G$\ddot{o}$rtler vortices are studied in the boundary-layer flows on concave surfaces of 1.0 and 2.0 m radius of curvature. The wavelengths of the vortices were pre-set by thin wires of 0.2 mm diameter placed 10 mm upstream and perpendicular to the concave surface leading edge. Velocity contours were obtained from velocity measurements using a single hot-wire anemometer probe. The most amplified or dominant wavelength is found to be 15 mm for free-stream velocity of 2.1 m/s and 3.0 m/s on the concave surface of R = 1 m and 2 m, respectively. The velocity contours in the cross-sectional planes at several streamwise locations show the growth and breakdown of the vortices. Three different regions can be identified based on the growth rate of the vortices. The occurrence of a secondary instability mode is also shown in the form of mushroom-like structures as a consequence of the non-linear growth of the G$\ddot{o}$rtler vortices. By pre-setting the vortex wavelength to be much larger and much smaller than the most amplified one, the splitting and merging of G$\ddot{o}$rtler vortices can be respectively observed.