• Title/Summary/Keyword: Wafer Shape

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Punching of Micro-Hole Array (미세 홀 어레이 펀칭 가공)

  • Son Y. K.;Oh S. I.;Rhim S. H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.09a
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    • pp.193-197
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    • 2005
  • This paper presents a method by which multiple holes of ultra small size can be punched simultaneously. Silicon wafers were used to fabricate punching die. Workpiece used in the present investigation were the rolled pure copper of $3{\mu}m$ in thickness and CP titanium of $1.5{\mu}m$ in thickness. The metal foils were punched with the dies and arrays of circular and rectangular holes were made. The diameter of holes ranges from $2-10{\mu}m$. The process set-up is similar to that of the flexible rubber pad forming or Guerin process. Arrays of holes were punched successfully in one step forming. The punched holes were examined in terms of their dimensions, surface qualities, and potential defect. The effects of the die hole dimension on ultra small size hole formation of the thin foil were discussed. The optimum process condition such as proper die shape and diameter-thickness ratio (d/t) were also discussed. The results in this paper show that the present method can be successfully applied to the fabrication of ultra small size hole array in a one step operation.

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Constructing a Three-Dimensional Endothelial Cell Layer in a Circular PDMS Microchannel

  • Choi, Jong Seob;Piao, Yunxian;Kim, Kyung Hoon;Seo, Tae Seok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.274.2-274.2
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    • 2013
  • We described a simple and efficient fabrication method for generating microfluidic channels with a circular-cross sectional geometry by exploiting the reflow phenomenon of a thick positive photoresist. Initial rectangular shaped positive photoresist micropatterns on a silicon wafer, which were fabricated by a conventional photolithography process, were converted into a half-circular shape by tuning the temperature to around $105^{\circ}C$. Through optimization of the reflow conditions, we could obtain a perfect circular micropattern of the positive photoresist, and control the diameter in a range from 100 to 400 ${\mu}m$. The resultant convex half-circular photoresist was used as a template for fabricating a concave polydimethylsiloxane (PDMS) through a replica molding process, and a circular PDMS microchannel was produced by bonding two half-circular PDMS layers. A variety of channel dimensions and patterns can be easily prepared, including straight, S-curve, X-, Y-, and T-shapes to mimic an in vivo vascular network. To inform an endothelial cell layer, we cultured primary human umbilical vein endothelial cells (HUVECs) inside circular PDMS microchannels, and demonstrated successful cell adhesion, proliferation, and alignment along the channel.

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VOID DEFECTS IN COBALT-DISILICIDE FOR LOGIC DEVICES

  • Song, Ohsung;Ahn, Youngsook
    • Journal of the Korean institute of surface engineering
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    • v.32 no.3
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    • pp.389-392
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    • 1999
  • We employed cobalt-disilicide for high-speed logic devices. We prepared stable and low resistant $CoSi_2$ through typical fabrication process including wet cleaning and rapid thermal process (RTP). We sputtered 15nm thick cobalt on the wafer and performed RTP annealing 2 times to obtain 60nm thick $CoSi_2$. We observed spherical shape voids with diameter of 40nm in the surface and inside $CoSi_2$ layers. The voids resulted in taking over abnormal junction leakage current and contact resistance values. We report that the voids in $CoSi_2$ layers are resulted from surface pits during the ion implantation previous to deposit cobalt layer. Silicide reaction rate around pits was enhanced due to Gibbs-Thompson effects and the volume expansion of the silicidation of the flat active regime trapped dimples. We confirmed that keeping the buffer oxide layer during ion implantation and annealing the silicon surface after ion implantation were required to prevent void defects in CoSi$_2$ layers.

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Nonuniformity of Conditioning Density According to CMP Conditioning System Design Variables Using Artificial Neural Network (인공신경망을 활용한 CMP 컨디셔닝 시스템 설계 변수에 따른 컨디셔닝 밀도의 불균일도 분석)

  • Park, Byeonghun;Lee, Hyunseop
    • Tribology and Lubricants
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    • v.38 no.4
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    • pp.152-161
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    • 2022
  • Chemical mechanical planarization (CMP) is a technology that planarizes the surfaces of semiconductor devices using chemical reaction and mechanical material removal, and it is an essential process in manufacturing highly integrated semiconductors. In the CMP process, a conditioning process using a diamond conditioner is applied to remove by-products generated during processing and ensure the surface roughness of the CMP pad. In previous studies, prediction of pad wear by CMP conditioning has depended on numerical analysis studies based on mathematical simulation. In this study, using an artificial neural network, the ratio of conditioner coverage to the distance between centers in the conditioning system is input, and the average conditioning density, standard deviation, nonuniformity (NU), and conditioning density distribution are trained as targets. The result of training seems to predict the target data well, although the average conditioning density, standard deviation, and NU in the contact area of wafer and pad and all areas of the pad have some errors. In addition, in the case of NU, the prediction calculated from the training results of the average conditioning density and standard deviation can reduce the error of training compared with the results predicted through training. The results of training on the conditioning density profile generally follow the target data well, confirming that the shape of the conditioning density profile can be predicted.

High Frequency Properties of Patterned Fe-Al-O Thin Films

  • N.D. Ha;Park, B.C.;B.K. Min;Kim, C.G.;Kim, C.O.
    • Proceedings of the Korean Magnestics Society Conference
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    • 2003.06a
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    • pp.194-194
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    • 2003
  • As a result of the recent miniaturization an enhancement in the performance of thin film inductors and thin film transformers, there are increased demands for the thin films with high magnetic permeability in the high frequency range, high saturation magnetization, in high electrical resistivity, and low coercive force. In order to improve high frequency properties, we will investigate anisotropy field by shape and size of pattern. The Fe-Al-O thin films of 16mm and 1 $\mu\textrm{m}$ thickness were deposited on Si wafer, using RF magnetron reactive sputtering technique with the mixture of argon and oxygen gases. The fabricating conditions are obtained in the working partial pressure of 2mTorr, O$_2$ partial pressure of 5%, input power of 400W, and Al pellets on an Fe disk with purity of 99,9%. Magnetic properties of the continuous films as followed: the 4$\pi$M$\_$s/ of 19.4kG, H$\_$c/ of 0.6Oe, H$\_$k/ of 6.0Oe and effective permeability of 2500 up to 100㎒ were obtained. In this work, we expect to enhance effect of magnetic anisotropy on patterned of Fe-Al-O thin films.

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In Vitro Antitumor Activity of BCNU-Loaded PLGA Wafer Containing Additives (첨가제 함유 BCNU/PLGA웨이퍼의 in vitro 항암 활성)

  • Lee, Jin-Soo;An, Tae-Kun;Shin, Phil-Kyung;Chae, Ghang-Soo;Jeong, Je-Kyo;Lee, Bong;Cho, Sun-Hang;Khang, Gil-Son;Lee, Hai-Bang
    • Polymer(Korea)
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    • v.27 no.3
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    • pp.217-225
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    • 2003
  • We fabricated the 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine)-loaded PLGA wafers containing poly(N-vinylpyrrolidone) (PVP) or tedium chloride (NaCl) in order to control the release profile of drug in special shape (3 in diameter, 1 mm in thickness) by direct compression method. In vitro release profiles of BCNU could be controlled by additives contained in the wafers. Initial release amount, release rate and duration of BCNU could be controlled with presence of PVP or NaCl. In vitro antitumor activity accessed using 9L gliosarcoma cell line has been evaluated by assaying the viability of cells treated with BCNU released from the wafers containing additives resulting in continuous growth inhibition of 9L gliosarcoma tumor cells. Specially, the continuous growth inhibition of BCNU-loaded PLGA wafers containing additives was more effective than that of non-additive BCNU-loaded PLGA wafers. The cytotoxic effect of the drug from the wafers containing NaCl as compared to wafers containing PVP was more enhanced.

Growth of Nanocrystalline Diamond on W and Ti Films (W 및 Ti 박막 위에서 나노결정질 다이아몬드의 성장 거동)

  • Park, Dong-Bae;Myung, Jae-Woo;Na, Bong-Kwon;Kang, Chan Hyoung
    • Journal of the Korean institute of surface engineering
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    • v.46 no.4
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    • pp.145-152
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    • 2013
  • The growth behavior of nanocrystalline diamond (NCD) film has been studied for three different substrates, i.e. bare Si wafer, 1 ${\mu}m$ thick W and Ti films deposited on Si wafer by DC sputter. The surface roughness values of the substrates measured by AFM were Si < W < Ti. After ultrasonic seeding treatment using nanometer sized diamond powder, surface roughness remained as Si < W < Ti. The contact angles of the substrates were Si ($56^{\circ}$) > W ($31^{\circ}$) > Ti ($0^{\circ}$). During deposition in the microwave plasma CVD system, NCD particles were formed and evolved to film. For the first 0.5h, the values of NCD particle density were measured as Si < W < Ti. Since the energy barrier for heterogeneous nucleation is proportional to the contact angle of the substrate, the initial nucleus or particle densities are believed to be Si < W < Ti. Meanwhile, the NCD growth rate up to 2 h was W > Si > Ti. In the case of W substrate, NCD particles were coalesced and evolved to the film in the short time of 0.5 h, which could be attributed to the fact that the diffusion of carbon species on W substrate was fast. The slower diffusion of carbon on Si substrate is believed to be the reason for slower film growth than on W substrate. The surface of Ti substrate was observed as a vertically aligned needle shape. The NCD particle formed on the top of a Ti needle should be coalesced with the particle on the nearby needle by carbon diffusion. In this case, the diffusion length is longer than that of Si or W substrate which shows a relatively flat surface. This results in a slow growth rate of NCD on Ti substrate. As deposition time is prolonged, NCD particles grow with carbon species attached from the plasma and coalesce with nearby particles, leaving many voids in NCD/Ti interface. The low adhesion of NCD films on Ti substrate is related to the void structure of NCD/Ti interface.

Comparative Study on Very Similar Jeungdoga Scripts through Image Analysis - Fundamental Difference between Treasure No. 758-1 and Treasure No. 758-2 - (이미지 분석을 통한 매우 유사한 증도가(證道歌) 이본(異本)에 대한 비교연구 - 보물 제758-1호와 보물 제758-2호의 근본적인 차이점 -)

  • Yoo, Woo Sik;Kim, Jung Gon
    • Journal of Conservation Science
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    • v.37 no.6
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    • pp.791-800
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    • 2021
  • Photographic images of the Samseong-version (三省本: Korea's Treasure No. 758-1) and the Gongin-version (空印本: Korea's Treasure No. 758-2) of Nammyeongcheon Hwasangsong Jeungdoga (南明泉和尙頌證道歌: Nanmingquan Song Zhengdaoge) were compared and analyzed to investigate the differences between the two versions. According to a report in 2012 at the time of the designation of the Gongin-version as Korea's treasure, both versions were printed from the same woodblocks. The Gongin-version is presumed to be a later print than the Samseong-version. The two versions are very similar in format and shape of border lines and characters. It is difficult to determine the differences with the naked eye, even for experts. In this study, based on the printing characteristics observed from each version through image analysis, useful evidence to determine whether it was printed using the same or different woodblocks and the order of printing was collected. As a result of careful image comparison and analysis, we concluded that the Samseong- and the Gongin-version were printed from different woodblocks, or possibly different typesetting. It was difficult to agree with the content of the report that the Gongin-version was a later print than the Samseong-version. In addition, it was noted that the Gongin-version print has characteristics quite different from the typical characteristics of woodblock printing seen in the Samseong-version. Additional investigations and follow-up studies on the printing technology used for Gongin-version print and the timing of printing are recommended.

Study of On-chip Liquid Cooling in Relation to Micro-channel Design (마이크로 채널 디자인에 따른 온 칩 액체 냉각 연구)

  • Won, Yonghyun;Kim, Sungdong;Kim, Sarah Eunkyung
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.4
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    • pp.31-36
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    • 2015
  • The demand for multi-functionality, high density, high performance, and miniaturization of IC devices has caused the technology paradigm shift for electronic packaging. So, thermal management of new packaged chips becomes a bottleneck for the performance of next generation devices. Among various thermal solutions such as heat sink, heat spreader, TIM, thermoelectric cooler, etc. on-chip liquid cooling module was investigated in this study. Micro-channel was fabricated on Si wafer using a deep reactive ion etching, and 3 different micro-channel designs (straight MC, serpentine MC, zigzag MC) were formed to evalute the effectiveness of liquid cooling. At the heating temperature of $200^{\circ}C$ and coolant flow rate of 150ml/min, straight MC showed the high temperature differential of ${\sim}44^{\circ}C$ after liquid cooling. The shape of liquid flowing through micro-channel was observed by fluorescence microscope, and the temperarue differential of liquid cooling module was measuremd by IR microscope.

Cascaded Structure of the High-Temperature Superconducting Hairpin-Comb Filter (고온초전도 헤어핀 콤 여파기의 cascade 구조에 관한 연구)

  • Yun, Seok-Sun;Park, Hee-Chan;Park, Ik-Mo;Min, Byoung-Chul;Choi, Young-Hwan;Moon, Seung-Hyun;Lee, Seung-Min;Oh, Byung-Du
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.38 no.3
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    • pp.28-34
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    • 2001
  • To improve the skirt characteristic of the high-temperature superconducting filter, we proposed a structure of cascading two independent hairpin-comb filters with an identical frequency response. Resonators of the cascaded filter are arranged in the shape of a diamond so that it minimizes the cross coupling between the resonators. This structure can be used effectively to improve the skirt characteristic of the filter in limited area of a circular wafer. The simulated skirt characteristic of the 18 pole cascaded filter is more than 40dB/MHz attenuation below and above the passband.

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