• Title/Summary/Keyword: Velocity Particle

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Particle deposition on a semiconductor wafer larger than 100 mm with electrostatic effect (정전효과가 있는 100mm보다 큰 반도체 웨이퍼로의 입자침착)

  • Song, Gen-Soo;Yoo, Kyung-Hoon;Lee, Kun-Hyung
    • Particle and aerosol research
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    • v.5 no.1
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    • pp.17-27
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    • 2009
  • Particle deposition on a semiconductor wafer larger than 100 mm was studied experimentally and numerically. Particularly the electrostatic effect on particle deposition velocity was investigated. The experimental apparatus consisted of a particle generation system, a particle deposition chamber and a wafer surface scanner. Experimental data of particle deposition velocity were obtained for a semiconductor wafer of 200 mm diameter with the applied voltage of 5,000 V and PSL particles of the sizes between 83 and 495 nm. The experimental data of particle deposition velocity were compared with the present numerical results and the existing experimental data for a 100 mm wafer by Ye et al. (1991) and Opiolka et al. (1994). The present numerical method took into consideration the particle transport mechanisms of convection, Brownian diffusion, gravitational settling and electrostatic attraction in an Eulerian frame of reference. Based on the comparison of the present experimental and numerical results with the existing experimental results the present experimental method for a 200 mm semiconductor wafer was found to be able to present reasonable data.

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Effect of Particle Concentration on Digital Holographic PTV Measurement (입자 농도가 Digital Holographic PTV 측정에 미치는 영향에 관한 연구)

  • Kim Seok;Lee Sang-Joon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.10 s.253
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    • pp.929-934
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    • 2006
  • The digital HPTV(holographic particle tracking velocimetry) velocity field measurement system consists of four steps: recording, numerical reconstruction, particle extraction and velocity extraction. In the velocity extraction process, we improved the two frame PTV algorithm to extract 3-D displacement information of each particle located in 3D space. Because a digital CCD camera was used, some factors such as spatial resolution, numerical aperture, and particle concentration influenced on the performance of the developed digital HPTV. Especially, the particle concentration $(C_o)$ affected the reconstruction efficiency and recovery ratio in the numerical reconstruction and particle extraction procedure. In this paper, the effect of particle concentration reconstruction efficiency and recovery ratio were analyzed experimentally. Optimal particle concentration was found to be in the range of $C_o=11{\sim}17\;particles/mm^3$.

PIV 기법을 이용한 마하 2.0 초음속 노즐의 과대팽창 충격파구조에 대한 연구

  • 김정훈;안규복;김지호;윤영빈
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2002.04a
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    • pp.64-64
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    • 2002
  • Two dimensional velocity distributions outside a Mach 2.0 supersonic nozzle have been investigated using digital particle image velocimetry (PIV). Mean velocities, turbulence intensities, vorticity field and volume dilatation field are obtained from 300 instantaneous PIV images using 0.33 $\mu\textrm{m}$ $TiO_2$ particle. The seeding particle of larger size, 1.4 $\mu\textrm{m}$ $TiO_2$, is also used for the experimental measurements of velocity lag downstream of shock waves according to particle sizes. The results have been compared and analyzed with schlieren photographs and computational fluid dynamics (CFD) results for the velocity distribution, the locations of shock waves and over-expanded shock structure. It was shown that the locations of normal shock and shock waves can be resolved by the axial or radial velocities, and the velocity lag is more significantly increased due to particle inertia as a particle size increases. And it was also found that over-expanded shock structures call be predicted by volume dilatation fields, and streamwise turbulence intensities are influenced significantly by normal shock waves.

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Validation of Digital Holographic Particle Velocity Measurement System (디지털 홀로그래피 입자 속도 계측시스템의 검증)

  • Roh, H.S.;Kang, B.S.
    • Journal of ILASS-Korea
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    • v.18 no.3
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    • pp.119-125
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    • 2013
  • Digital holographic particle velocity measurement system can be a promising optical tool for the measurements of three dimensional particle velocities. In this research, validation experiments for the digital holographic particle velocity measurement system were conducted with measuring the velocities of glass beads on a rotating disk. Uncertainty analysis was performed to identify the sources of all relevant errors and to evaluate their magnitudes. The measurement results of particle velocities obtained with digital holographic method are compared reasonably well with the known values within acceptable range of errors. Moreover, digital holographic method showed better performance compared with that of optical holographic system.

Numerical Simulation of Particle Deposition on a Wafer Surface (웨이퍼 표면상의 입자침착에 관한 수치 시뮬레이션)

  • 명현국;박은성
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.9
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    • pp.2315-2328
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    • 1993
  • The turbulence effect of particle deposition on a horizontal free-standing wafer in a vertical flow has been studied numerically by using the low-Reynolds-number k-.epsilon. turbulence model. For both the upper and lower surfaces of the wafer, predictions are made of the averaged particle deposition velocity and its radial distribution. Thus, it is now possible to obtain local information about the particle deposition on a free-standing wafer. The present result indicates that the particle deposition velocity on the lower surface of wafer is comparable to that on the upper one in the diffusion controlled deposition region in which the particle sizes are smaller than $0.1{\mu}m$. And it is found in this region that, compared to the laminar flow case, the averaged deposition velocity under the turbulent flow is about two times higher, and also that the local deposition velocity at the center of wafer is high equivalent to that the wafer edge.

A PTV Applied to Measuring the Solid Particle Velocity of Slurry Flow in a Vertical Pipe (PTV를 이용한 수직관 내 슬러리유동의 고체입자 속도계측 연구)

  • Yang, Chan-Kyu;Choi, Jong-Su;Hong, Sup
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.10a
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    • pp.213-219
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    • 2001
  • In this paper, particle velocity of slurry flow, a kind of solid-particle two phase flow, was measured by using a particle tracking velocimetry. Particles are modeled by sphere-shaped glass whose diameters are 3mm, 5mm, and 7mm At first, a particle which is falling in the water is captured and analyzed to give their free falling velocity. The falling velocity was very high up to about 4m/sec in the air, which needs special algorithm for the accurate measurement. For the upwelling slurry flow in the straight duct, there are some noises caused by cavity. However, the effect was so small that it does not affect the measurement of large particles. From the preliminary study of applying the PTV to measurement of particle movement in slurry flow, we could find out the optimum value of parameters: threshold value., searching area radius and correlation area size.

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Measurement of Particle Deposition Velocity Toward a Vertical Wafer Surface (수직 웨이퍼상의 입자 침착속도의 측정)

  • Bae, G.N.;Lee, C.S.;Park, S.O.;Ahn, K.H.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.3
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    • pp.521-527
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    • 1995
  • The average particle deposition velocity toward a vertical wafer surface in a vertical airflow chamber was measured by a wafer surface scanner(PMS Model SAS-3600). Polystyrene latex(PSL) spheres with diameters between 0.3 and $0.8{\mu}m$ were used. To examine the effect of the airflow velocity on the deposition velocity, experiments were conducted for three vertical airflow velocities ; 20, 30, 50cm/s. Experimental data of particle deposition velocity were compared with those given by prediction model suggested by Liu and Ahn(1987).

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Research on Acceleration Mechanism of Inflight Particle and Gas Flow Effect for the Velocity Control in Vacuum Kinetic Spray Process (진공상온분사(VKS) 공정에서의 비행입자 가속 기구 및 속도제어를 위한 가스 유량 효과에 관한 연구)

  • Park, Hyungkwon;Kwon, Juhyuk;Lee, Illjoo;Lee, Changhee
    • Korean Journal of Materials Research
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    • v.24 no.2
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    • pp.98-104
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    • 2014
  • Vacuum kinetic spray(VKS) is a relatively advanced process for fabricating thin/thick and dense ceramic coatings via submicron-sized particle impact at room temperature. However, unfortunately, the particle velocity, which is an important value for investigating the deposition mechanism, has not been clarified yet. Thus, in this research, VKS average particle velocities were derived by numerical analysis method(CFD: computational fluid dynamics) connected with an experimental approach(SCM: slit cell method). When the process gas or powder particles are accelerated by a compressive force generated by gas pressure in kinetic spraying, a tensile force generated by the vacuum in the VKS system accelerates the process gas. As a result, the gas is able to reach supersonic speed even though only 0.6MPa gas pressure is used in VKS. In addition, small size powders can be accelerated up to supersonic velocity by means of the drag-force of the low pressure process gas flow. Furthermore, in this process, the increase of gas flow makes the drag-force stronger and gas distribution more homogenized in the pipe, by which the total particle average velocity becomes higher and the difference between max. and min. particle velocity decreases. Consequently, the control of particle size and gas flow rate are important factors in making the velocity of particles high enough for successful deposition in the VKS system.

Numerical study of particle dispersion from a power plant chimney (발전소 굴뚝에서의 입자 분산에 대한 수치해석)

  • Shim, Jeongbo;You, Donghyun
    • Particle and aerosol research
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    • v.13 no.4
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    • pp.173-182
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    • 2017
  • An Eulerian-Lagrangin approach is used to compute particle dispersion from a power plant chimney. For air flow, three-dimensional incompressible filtered Navier-Stokes equations are solved with a subgrid-scale model by integrating the Newton's equation, while the dispersed phase is solved in a Lagrangian framework. The velocity ratios between crossflow and a jet of 0.455 and 0.727 are considered. Flow fields and particle distribution of both cases are evaluated and compared. When the velocity ratio is 0.455, it demonstrates a Kelvin-Helmholtz vortex structure above the chimney caused by the interaction between crossflow and a jet, whereas the other case shows flow structures at the top of the chimney collapsed by fast crossflow. Also, complex wake structures cause different particle distributions behind the chimney. The case with the velocity ratio of 0.727 demonstrates strong particle concentration at the vortical region, whereas the case with the velocity ratio of 0.455 shows more dispersive particle distribution. The simulation result shows similar tendency to the experimental result.

Distortion of Eelectrical Double Layer in Liquid Filtration by Fibrous Filters

  • Lee, Myong-Hwa;Hirose, Shogo;Otani, Yoshio
    • Particle and aerosol research
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    • v.10 no.3
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    • pp.99-108
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    • 2014
  • Liquid filtration by membrane filters is essential for the preparation of ultrapure water in semiconductor manufacturing processes. The separation of submicrometer particles suspended in ultrapure water with a laminated fibrous membrane filter was studied numerically and experimentally in the present work. We found that an electrical double layer around a single fiber expanded to a large extent at a low ion concentration, as in ultrapure water, and deformed toward the upstream of the fiber with increasing filtration velocity. Since an increase in the electrical double-layer thickness leads to a decrease in the electrical potential gradient, particles with the same polarity as the fiber approach the fiber more easily and are captured at a high filtration velocity. Experimental results also confirmed that the collection efficiency of polystyrene latex(PSL) particles through a PTFE filter became higher as the filtration velocity increased.