• Title/Summary/Keyword: Micro-hole target

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Effects of the Micro-hole Target Structures on the Laser-driven Energetic Proton Generation

  • Pae, Ki-Hong;Choi, Il-Woo;Hahn, Sang-June;Lee, Jong-Min
    • Journal of the Optical Society of Korea
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    • v.13 no.1
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    • pp.48-52
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    • 2009
  • Micro-hole targets are studied to generate energetic protons from laser-thin foil targets by using 2-dimensional particle-in-cell simulations. By using a small hole, the maximum energy of the accelerated proton is increased to 4 times higher than that from a simple planar target. The main proton acceleration mechanism of the hole-targets is the electrostatic field created between the fast electrons accelerated by the laser pulse ponderomotive force combined with the vacuum heating and the target rear surface. But in this case, the proton angular distribution shows double-peak shape, which means poor collimation and low current density. By using a small cone-shaped hole, the maximum proton energy is increased 3 times higher than that from a simple planar target. Furthermore, the angular distribution of the accelerated protons shows good collimation.

Fume Particle Dispersion in Laser Micro-Hole Machining with Oblique Stagnation Flow Conditions (경사 정체점 유동이 적용된 미세 홀 레이저 가공 공정의 흄 오염입자 산포특성 연구)

  • Kim, Kyoungjin;Park, Joong-Youn
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.3
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    • pp.77-82
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    • 2021
  • This numerical study focuses on the analysis of fume particle dispersion characteristics over the surface of target workpiece in laser micro-hole machining process. The effects of oblique stagnation flow over fume generating machining point are examined by carrying out a series of three-dimensional random particle simulations along with probabilistic particle generation model and particle drag correlation of low Reynolds number. Present computational model of fume particle dispersion is found to be capable of assessing and quantifying the fume particle contamination in precision hole machining which may influenced by different types of air flow patterns and their flow intensity. The particle size dependence on dispersion distance of fume particles from laser machining point is significant and the effects of increasing flow oblique angle are shown quite differently when slot blowing or slot suction flows are applied in micro-hole machining.

A Study on the Optimal Conditions of Hole Machining of Microplate by Application of Response Surface Methodology in Wire-Pulse Electrochemical Machining (와이어 펄스전해가공에서 반응표면분석법을 응용한 미세박판의 홀 가공 최적 조건에 관한 연구)

  • Song, Woo-Jae;Lee, Eun-Sang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.5
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    • pp.141-149
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    • 2017
  • Due to the inaccuracy of micro-machining, various special processing methods have been investigated recently. Among them, pulse electrochemical machining is a promising machining method with the advantage of no residual stress and thermal deformation. Because the cross section of the wire electrode used in this study is circular, wire-pulse electrochemical machining is suitable for micro-hole machining. By applying the response surface methodology, the experimental plan was made of three factors and three levels: machining time, duty factor, and voltage. The regression equation was obtained through experiments. Then, by referring to the main effect diagram, we fixed the duty factor and machining time with little relevance, and solved the equation for the target 900 microns to obtain the voltage value. The results obtained from the response surface methodology were approximately those of the target value when the actual experiment was carried out. Therefore, it is concluded that the optimal conditions for hole processing can be obtained by the response surface methodology.

A Parallel Mode Confocal System using a Micro-Lens and Pinhole Array in a Dual Microscope Configuration (이중 현미경 구조를 이용한 마이크로 렌즈 및 핀홀 어레이 기반 병렬 공초점 시스템)

  • Bae, Sang Woo;Kim, Min Young;Ko, Kuk Won;Koh, Kyung Chul
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.11
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    • pp.979-983
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    • 2013
  • The three-dimensional measurement method of confocal systems is a spot scanning method which has a high resolution and good illumination efficiency. However, conventional confocal systems had a weak point in that it has to perform XY axis scanning to achieve FOV (Field of View) vision through spot scanning. There are some methods to improve this problem involving the use of a galvano mirror [1], pin-hole array, etc. Therefore, in this paper we propose a method to improve a parallel mode confocal system using a micro-lens and pin-hole array in a dual microscope configuration. We made an area scan possible by using a combination MLA (Micro Lens Array) and pin-hole array, and used an objective lens to improve the light transmittance and signal-to-noise ratio. Additionally, we made it possible to change the objective lens so that it is possible to select a lens considering the reflection characteristic of the measuring object and proper magnification. We did an experiment using 5X, 2.3X objective lens, and did a calibration of height using a VLSI calibration target.

Design of High frequency Vibration Mechanism with PZT actuator for Ultraprecision Laser Machining (압전구동기를 이용한 초정밀레이저 가공의 고주파진동 장치설계)

  • Kim, Hyun-Uk;Hwang, Dong-Hyun;Park, Jong-Kweon;Cho, Sung-Hak;Lee, Moon-G.
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.3
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    • pp.419-425
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    • 2010
  • To machine the micro hole, laser machining system is widely used, however, the system cannot fabricate the micro hole with high aspect ratio and good surface finish. To break the obstacles, the high frequency vibration mechanism with PZT (Piezoelectric Transducers) is proposed in this paper. The mechanism will vibrate the laser beam in vertical direction so that the aspect ratio and surface finish may be higher than the conventional. The mechanism vibrates the eyepiece of laser optics. In addition to the benefits, the mechanism enables us to have high precision and flexibility. It decreases burr and debris during machining. And it is able to machine various materials of workpiece. This research include high frequency and large travel range of the proposed mechanism. The PZT motion of mechanism and analysis on the sensitivity of design parameters are extracted from a finite element method (FEM) simulation. In the analysis, the target vibration mode without parasitic motion is designated to have the target frequency and high amplitude.

A Micro-robotic Platform for Micro/nano Assembly: Development of a Compact Vision-based 3 DOF Absolute Position Sensor (마이크로/나노 핸들링을 위한 마이크로 로보틱 플랫폼: 비전 기반 3자유도 절대위치센서 개발)

  • Lee, Jae-Ha;Breguet, Jean Marc;Clavel, Reymond;Yang, Seung-Han
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.1
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    • pp.125-133
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    • 2010
  • A versatile micro-robotic platform for micro/nano scale assembly has been demanded in a variety of application areas such as micro-biology and nanotechnology. In the near future, a flexible and compact platform could be effectively used in a scanning electron microscope chamber. We are developing a platform that consists of miniature mobile robots and a compact positioning stage with multi degree-of-freedom. This paper presents the design and the implementation of a low-cost and compact multi degree of freedom position sensor that is capable of measuring absolute translational and rotational displacement. The proposed sensor is implemented by using a CMOS type image sensor and a target with specific hole patterns. Experimental design based on statistics was applied to finding optimal design of the target. Efficient algorithms for image processing and absolute position decoding are discussed. Simple calibration to eliminate the influence of inaccuracy of the fabricated target on the measuring performance also presented. The developed sensor was characterized by using a laser interferometer. It can be concluded that the sensor system has submicron resolution and accuracy of ${\pm}4{\mu}m$ over full travel range. The proposed vision-based sensor is cost-effective and used as a compact feedback device for implementation of a micro robotic platform.

BEAD BASED CHEMICAL REACTION SYSTEM USING TEMPERATURE AND FLUID CONTROL FOR CANCER DETECTION (유체와 온도 조절을 이용한 생화학 물질 반응용 마이크로칩의 개발)

  • Kim, Min-Su;Lee, Bo-Rahm;Yoon, Hyo-Jin;Kim, Byung-Gee;Lee, Yoon-Sik;Kim, Yong-Kweon
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1466-1467
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    • 2008
  • We describe here a novel micro total analysis system for the purification and identification of the affinity-captured proteins. Also we demonstrated the mass analysis of the Carcinoembrionic antigen (CEA) and Alpha femtoprotein which were chosen as the target cancer marker. For MALDI-TOF analyses, the proteins should to be separated from a protein mixture and be concentrated when needed. This procedure usually takes a long time even before protease-digested samples are to be obtained from them. Here, we describe integrated and efficient micro chip for protein purification and digestion for MALDI-TOF analyses. At first, disease protein is purified by passing the micro chamber from a protein mixture or human whole serum and released from the micro affinity beads by thermal heating. Purified protein is then transfer to the hole for trypsin digestion. The final sample is analyzed by MALDI-TOF. All the processes could be finished successfully within one hour, which renders MALDI-TOF analyses of a target protein quite simple.

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Development and Characterization of Vertical Type Probe Card for High Density Probing Test (고밀도 프로빙 테스트를 위한 수직형 프로브카드의 제작 및 특성분석)

  • Min, Chul-Hong;Kim, Tae-Seon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.9
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    • pp.825-831
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    • 2006
  • As an increase of chip complexity and level of chip integration, chip input/output (I/O) pad pitches are also drastically reduced. With arrival of high complexity SoC (System on Chip) and SiP (System in Package) products, conventional horizontal type probe card showed its limitation on probing density for wafer level test. To enhance probing density, we proposed new vertical type probe card that has the $70{\mu}m$ probe needle with tungsten wire in $80{\mu}m$ micro-drilled hole in ceramic board. To minimize alignment error, micro-drilling conditions are optimized and epoxy-hardening conditions are also optimized to minimize planarity changes. To apply wafer level test for target devices (T5365 256M SDRAM), designed probe card was characterized by probe needle tension for test, contact resistance measurement, leakage current measurement and the planarity test. Compare to conventional probe card with minimum pitch of $50{\sim}125{\mu}m\;and\;2\;{\Omega}$ of average contact resistance, designed probe card showed only $22{\mu}$ of minimum pitch and $1.5{\Omega}$ of average contact resistance. And also, with the nature of vertical probing style, it showed comparably small contact scratch and it can be applied to bumping type chip test.

Phase identification and degree of orientation measurements far fine-grained rock forming minerals using micro-area X-ray diffractometer -$Al_{2}SiO_{5}$ Polymorphs- (미소부 X-선 회절분석기를 이용한 미립조암광물의 상동정 및 배향도 측정 -$Al_{2}SiO_{5}$ 3상다형-)

  • 박찬수;김형식
    • The Journal of the Petrological Society of Korea
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    • v.9 no.4
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    • pp.205-210
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    • 2000
  • Measurements of phase identification and degree of orientation for fine-grained (about 0.3 mm in diameter) minerals in rock samples performed by micro-area X-ray diffractometer.$Al_{2}SiO_{5}$ polymorphs (andalusite, kyanite and sillimanite) were chosen for the measurements and target minerals were existed on thin sections. Micro-area X-ray diffractometer is composed of 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillating goniometer and position sensitive proportional counter (PSPC). $CuK_{\alpha}$ radiation was used as X-ray source and a pin hole ($50\;\mu\textrm{m}$$ in diameter) collimator was selected to focus radiation X-ray onto the target minerals. Phase identification and diffracted X-ray peak indexing were carried out by 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillation measurement. Then, 2(${\omega}\;{\phi}$)-circle oscillation measurement was made for the purpose of searching the prevailing lattice plane of the minerals on thin section surface. Finally, for a selected peak by 2-circle oscillation measurement, X-ray pole figure measurement was executed for the purpose of check the degree of orientation of the single lattice direction and examine its pole distribution. As a result of 3-circle oscillation measurement, it was possible that phase identification among $Al_{2}SiO_{5}$ polymorphs. And from the results of 2-circle oscillation measurement and X-ray pole figure measurement, we recognized that poles of andalusite (122), kyanite (200) and sillimanite (310) lattice plances were well developed with direction normal to each mineral surface plane respectively. Therfore, the measurements used with micro-area X-ray diffractometer in this study will be a useful tool of phase identification and degree of orientation measurement for fine-grained rock forming minerals.

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