• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 Proceedings of 5th International Joint Symposium on Microeletronics and Packaging
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• pp.19-25
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• 2000

Dielectric polymer films produced from benzocyclobutene (BCB) formulations (CYCLOTENE＊ family resins) are known to possess many desirable properties for microelectronic applications; for example, low dielectric constant and dissipation factor, low moisture absorption, rapid curing on hot plate without reaction by-products, minimum shrinkage in curing process, and no Cu migration issues. Recently, BCB-based products for thick film applications have been developed, which exhibited excellent dissipation factor and dielectric constant well into the GHz range, 0.002 and 2.50, respectively. Derived from these properties, the applications are developed in: bumping/wafer level packaging, Ga/As chip ILD, optical waveguide, flat panel display, and lately in BCB-coated Cu foil for build-up board. In this paper, we review the relevant properties of BCB, then the application areas in bumping/wafer level packaging and BCB-coated Cu foil for build-up board.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 추계학술대회 논문집
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• pp.22-27
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• 1992

Phosphorus doped hydrogenated microcrystalline silicon (${\mu}c$-Si:H) thin films were deposited by PECVD (Plasma Enhanced Chemical Vapour Deposition) method using 10.2% $SiH_4$ gas (diluted in Ar) and 308ppm $PH_3$ gas (diluted in Ar). The structural, optical and electrical properties of the films were investigated as a function of substrate temperature(15 to $400^{\circ}C$) and RF power(10 to 120W). The thin film deposited by varing substrate temperature had columnar structure and microcrystalline phase. The volume fraction of microcrystalline phase in the films deposited at RF power of 80W, increased with increasing substrate temperature up to $200^{\circ}C$, and then decreased with further increasing substrate temperature. Volume fraction of microcrystalline phase increased monotonously with increasing RF power at substrate temperature of $250^{\circ}C$. With increasing volume fraction of microcrystalline, electrical resistivity of films decreased to 0.274 ${\Omega}cm$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.1-4
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• 2004

Polycrystalline CdSe thin films were grown on ceramic substrate using a chemical bath deposition(CBD)method. They were annealed at various temperature and X-ray diffraction patterns were measured by X-ray diffractometer in order to study CdSe polycrystal structure. Using extrapolation method of X-ray diffraction patterns for the CdSe samples annealed in $N_2$ gas at $450^{\circ}C$ it was found hexagonal structure whose lattice parameters $a_0$ and $c_0$ were $4.302{\AA}$ and 7.014 ${\AA}$, respectively. Its grain size was about 0.3 ${\mu}m$. Hall effect on this sample was measured by Van der Pauw method and studied on carrier density and movility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33K and 200K, and by polar optical scattering at temperature range of 200K and 293K. We measured also spectral response, sensitivity$(\gamma)$, maximum allowable power dissipation and response time on these samples.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1645-1647
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• 1996

Polycrystalline CdTe thin films -have been studied for photovoltaic application because of their high absorption coefficient and optimal band gap energy (1.54 eV) for solar energy conversion. In this study, we prepared CdTe films using RF-magnetron sputtering method and investigated structural, optical and electrical properties with spectrophotometer, XRD, EDX, and resistivity meter. CdTe films at $200\;^{\circ}C$ showed a mixture of zinc blend (Cubic) and wurtzite (hexagonal) phase. On the other hand, the films at $400\;^{\circ}C$ showed highly oriented structure having hexagonal structure. The resistivity of CdTe films deposited on $SiO_2$ substrates was about $10_7\;{\Omega}cm$. The value of resistivity decreased with the increase of the substrate temperature. CdTe were sputtered on CdS thin films prepared by chemical bath deposition for the formation of the heterojunction. I-V characteristics of these cells were measured at a light density of $100mw/cm^2$, AM. 1.0. The present thin film solar cells showed a conversion efficiency of about 5%.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.242-248
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• 2008

The structural, optical and electrical properties of ZnO films doped with 1.5 at% of 3A materials(B, Al, Ga, In) were studied by sol-gel process. The films were found to be c-axis (002) oriented hexagonal structure on glass substrate, when post heated at 500 $^{\circ}C$. The surface of the films showed a uniform and nano size microstructure and the crystalline size of doped films decreased. The lattice constants of ZnO:B/Al/Ga increased than that of ZnO, while ZnO:In decreased. All the films were highly transparent(above 90 %) in the visible region. The energy gaps of ZnO:B/Al/Ga were increased a little, but that of ZnO:In was not changed. The resistivities of ZnO:Al/Ga/In were less than 0.1 $\Omega$cm. All the films showed a semiconductor properties in the light or temperature, however ZnO:In was less sensitive to it. A figure of merit of ZnO:In had the highest value of 0.025 $\Omega^{-1}$ in all samples.

• 한국전기전자재료학회논문지
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• 제25권4호
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• pp.290-293
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• 2012

This article introduces the characterization of spin coated ZnO transparent conducting oxide on the flexible substrates. As a II-IV compound semiconductor, ZnO has a wide band gap of 3.37 eV with transparent properties. Due to this transparent properties, ZnO materials can be also employed as the transparent conducting electrode materials. Therefore, strong demands have been required for the transparent electrodes with low temperature processing and cheap cost. So, We will investigate the electrical property and optical transmittance of ZnO transparent conducting oxide through the 4-point probe resistivity meter, and ultraviolet-vis spectrometer Lamda 35, respectively.

• 한국주조공학회지
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• 제33권3호
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• pp.127-133
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• 2013

The influences of a small amount of CaO addition on the microstructure and corrosion behavior of AZ81 casting alloy have been investigated by means of optical microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, immersion and electrochemical tests. The added CaO led to the refinement of ${\alpha}$-Mg grains and the decrease in ${\beta}$ precipitate content by the formation of an $Al_2Ca$ phase. The AZ81-CaO alloy had a better corrosion resistance than the AZ81 alloy. The microstructural characterization on the corroded surface revealed that the enhanced corrosion resistance of the CaO-containing alloy may well be ascribed to the increased barrier effect of precipitates formed more continuously along the grain boundaries and the incorporation of Al and Ca elements into the corrosion film, by which it became more protective.

• 한국응용과학기술학회지
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• 제26권3호
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• pp.288-296
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• 2009

In this study, the silica-based hybrid material with high barrier property was prepared by incorporating ethylene-vinyl alcohol (EVOH) copolymer, which has been utilized as packaging materials due to its superior gas permeation resistance, during sol-gel process. In preparation of this EVOH/$SiO_2$ hybrid coating materials, the (3-glycidoxy-propyl)-trimethoxysilane (GPTMS) as a silane coupling agent was employed to promote interfacial adhesion between organic and inorganic phases. As confirmed from FT-IR analysis, the physical interaction between two phases was improved due to the increased hydrogen bonding, resulting in homogeneous microstructure with dispersion of nano-sized silica particles. However, depending on the range of content of added silane coupling agent (GPTMS), micro-phase separated microstructure in the hybrid could be observed due to insufficient interfacial attraction or possibility of polymerization reaction of epoxide ring in GPTMS. The oxygen barrier property of the mono-layer coated BOPP (biaxially oriented polypropylene) film was examined for the hybrids containing various GPTMS contents. Consequently, it is revealed that GPTMS should be used in an optimum level of content to produce the high barrier EVOH/$SiO_2$ hybrid material with an improved optical transparency and homogeneous phase morphology.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.99-99
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• 2010

Recently, amorphous transparent oxide semiconductors (TOS) have been widely studied for many optoelectronic devices such as AM-OLED (active-matrix organic light emitting diodes). The TOS TFTs using a-IGZO channel layers exhibit a high electron mobility, a smooth surface, a uniform deposition at a large area, a high optical transparency, a low-temperature fabrication. In spite of many advantages of the sputtering process such as better step coverage, good uniformity over large area, small shadow effect and good adhesion, there are not enough researches about characteristics of a-IGZO thin films. In this study, therefore, we focused on the electrical properties of a-IGZO thin films as a channel layer of TFTs. TFTs with the a-IGZO channel layers and Y2O3 gate insulators were fabricated. Source and drain layers were deposited using ITO target. TFTs were deposited on unheated non-alkali glass substrates ($5cm{\times}5cm$) with a sintered ceramic IGZO disc (3 inch $\varnothing$, 5mm t), Y2O3 disc (3 inch $\varnothing$, 5mm t) and ITO disc (3 inch $\varnothing$, 5mm t) as a target by magnetron sputtering method. The O2 gas was used as the reactive gas. Deposition was carried out under various sputtering conditions to investigate the effect of sputtering process on the characteristics of a-IGZO thin films. Correlation between sputtering factors and electronic properties of the film will be discussed in detail.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.204-204
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• 2010

본 연구에서는 Glass 기판 위에 우수한 광 투과도를 갖는 ZnO 기반의 Thin Film Transistor (TFT)를 제작하였으며, 이에 대한 전기적 및 광학적 특성을 분석하였다. 소자 구조의 제작은 Maskless Aligner를 이용한 Optical lithograph법을 이용하였다. 채널층은 ZnO로 하였고 Source/Drain 영역은 GaZnO로 하여 전체구조가 ZnO 기반의 homogeneity를 유지하게 하였다. 이때 Gate 절연막은 Bi1.5Zn1Nb1.5O7와 SiO2 두가지 종류로 하여 각각의 특성을 비교하였다. 본연구에서 TFT구조의 각 층은 모두 r. f. 마그네트론 스퍼터법으로 증착하였다. 제작된 TFT들은 채널층 및 절연막 형성 등에 관여된 세부적 실험변수의 변화에 관계없이 약 75% 이상의 우수한 광투과도 특성을 보였다. 전기적 특성 평가에서, 제작된 TFT들은 전반적으로 비교적 낮은 문턱전압과 높은 이동도를 보였다. 하지만, 트랜지스터의 전기적 전송 특성의 주요 인자들인 채널-이동도, 스위칭, 누설 및 이력 등은 ZnO 채널층 혹은 Bi1.5Zn1Nb1.5O7 절연막 형성 시 주입되는 O2 가스의 분압에 의존하는 것이 관측되었다. 이를 통하여 트랜지스터의 각 세부 영역의 구조 및 형성 조건이 트랜지스터의 전기적 특성에 미치는 영향과 상관관계에 대하여 논의한다.