• Title/Summary/Keyword: Parasitic motion

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The Analysis of Motion Error in Scanning Type XY Stage (스캐닝 방식 XY 스테이지의 운동오차 분석)

  • 황주호;박천홍;이찬홍;김동익;김승우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.1380-1383
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    • 2004
  • The scanning type XY stage is frequently used these days as precision positioning system in equipment for semiconductor or display element. It is requested higher velocity and more precise accuracy for higher productivity and measuring performance. The position accuracy of general stage is primarily affected by the geometric errors caused by parasitic motion of stage, misalignments such as perpendicular error, and thermal expansion of structure. In the case of scanning type stage, H type frame is usually used as base stage which is driven by two actuators such as linear motor. In the point view of scanning process, the stage is used in moving motion. Therefore, dynamic variation is added as significant position error source with other parasitic motion error. Because the scanning axis is driven by two actuators with two position detectors, 2 dimensional position errors have different characteristic compared to general tacked type XY stage. In this study 2D position error of scanning stage is analyzed by 1D heterodyne interferometer calibrator, which can measure 1D linear position error, straightness error, yaw error and pitch error, and perpendicular error. The 2D position error is evaluated by diagonal measurement (ISO230-6). The yaw error and perpendicular error are compensated on the base stage of scanning axis. And, the horizontal straightness error is compensated by cross axis compensation. And, dynamic motion error in scanning motion is analyzed.

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Modeling and optimal design of monolithic precision XYZ-stage using flexure mechanism (유연기구를 이용한 초정밀 단일체 3축 스테이지의 모델링 및 최적설계에 관한 연구)

  • Shim, Jong-Yeop;Gweon, Dae-Gab
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.4
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    • pp.868-878
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    • 1998
  • There are recently increasing needs for precision XYZ-stage in the fields of nanotechnology, specially in AFMs(Atomic Force Microscope) and STMs(Scanning Tunneling Microscope). Force measurements are made in the AFM by monitoring the deflection of a flexible element (usually a cantilever) in response to the interaction force between the probe tip and the sample and controlling the force neasyred constant topography can be obtained. The power of the STM is based on the strong distance dependence of the tunneling current in the vacuum chamber and the current is a feedback for the tip to trace the surface topography. Therefore, it is required for XYZ-stage to position samples with nanometer resolution, without any crosscouples and any parasitic motion and with fast response. Nanometer resolution is essential to investigate topography with reasonable shape. No crosscouples and parasitic motion is essential to investigate topography without any shape distortion. Fast response is essential to investigate topography without any undesirable interaction between the probe tip and sample surface ; sample scratch. To satisfy these requirements, this paper presents a novel XYZ-stage concept, it is actuated by PZT and has a monolithic flexible body that is made symmetric as possible to guide the motion of the moving body linearly. PZT actuators have a very fast response and infinite resolution. Due to the monolithic structure, this XYZ-stage has no crosscouples and by symmetry it has no parasitic motion. Analytical modeling of this XYZ-stage and its verification by FEM modeling are performed and optimal design that is to maximize 1st natural frequencies of the stage is also presented and with that design values stage is manufactured.

The design of XYZ 3-axis stage for AFM system (AFM 시스템을 위한 XYZ 3축 스테이지의 설계)

  • 김동민;김기현;심종엽;권대갑;엄천일
    • Proceedings of the Korea Crystallographic Association Conference
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    • 2002.11a
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    • pp.36-36
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    • 2002
  • To Establish of standard technique of length measurent in 2D plane, we develope AFM system. The XY scanner scans the sample only in XY plane, while the Z scanner scans the specimen only in Z-direction. Cantilever tip is controlled to has constant height relative to speciman surface by feedback of PSPD signal. To acquire high accuracy, Z-axis measuring sensor will be added.(COXI or others). In this paper we design XYZ stage suitable for this AEM system. For XY stage, single module parallel-kinnematic flexure stage is used which has high orthogonality and minimum out-of-plane motion. To obtain best performance optimal design is performed. For XY stage, to be robust about parasitic motion optimal design of maximizing Z and tilt stiffness is performed under the constraint of motion range and stage size. And for Z stage, optimal design of maximizing 1st resonant frequency is performed. Because if resonant frequency is get higher, scan speed is improved. So it makes reduce the error by sensor drift. Resultly XYZ stage each have 1st natural frequency of 115㎐, 201㎐, 2.66㎑ and range 109㎛, 110㎛, 12㎛.

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Robust deterministic control for robotic manipulators with uncertainties

  • Kang, Chul-Goo;Horowitz, Roberto;Leitmann, George
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.687-693
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    • 1989
  • A robust deterministic control for a class of singularly perturbed uncertain systems, where uncertainties are characterized deterministically rather than stochastically, is developed based mainly on information available on an uncertain reduced-order system. The deterministic control scheme is applied to the motion control of a n degree of freedom robotic manipulator. The parasitic actuator and sensor dynamics of the manipulator are explicitly considered in the stability analysis of the deterministic controller using a singular perturbation model. Simulation and experimental studies for a two degree of freedom, direct drive SCARA manipulator are conducted to evaluate the effectiveness of the derived control scheme.

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Optimal design of a flexure hinge-based XY AFM scanner for minimizing Abbe errors and the evaluation of measuring uncertainty of AFM system (원자현미경용 XY 스캐너의 아베 오차 최소화를 위한 최적 설계 및 원자 현미경의 측정 불확도 평가)

  • Kim D.M.;Lee D.Y.;Gweon D.G.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1438-1441
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    • 2005
  • To establish of standard technique of nano-length measurement in 2D plane, new AFM system has been designed. In this system, measurement uncertainty is dominantly affected by the Abbe error of XY scanning stage. No linear stage is perfectly straight; in other words, every scanning stage is subject to tilting, pitch and yaw motion. In this paper, an AFM system with minimum offset of XY sensing is designed. And XY scanning stage is designed to minimize rotation angle because Abbe errors occur through the multiply of offset and rotation angle. To minimize the rotation angle optimal design has performed by maximizing the stiffness ratio of motion direction to the parasitic motion direction of each stage. This paper describes the design scheme of full AFM system, especially about XY stage. Full range of fabricated XY scanner is $100um\times{100um}$. And tilting, pitch and yaw motion are measured by autocollimator to evaluate the performance of XY stage. Using this AFM system, 3um pitch specimen was measured. As a result, the uncertainty of total system has been evaluated.

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Analysis and extraction method of noise parameters for short channel MOSFET thermal noise modeling (단채널 MOSFET의 열잡음 모델링을 위한 잡음 파라메터의 분석과 추출방법)

  • Kim, Gue-Chol
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.12
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    • pp.2655-2661
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    • 2009
  • In this paper, an accurate noise parameters for thermal noise modeling of short channel MOSFET is derived and extracted. Fukui model for calculating the noise parameters of a MOSFET is modified by considering effects of parasitic elements in short channel, and it is compared with conventional noise model equation. In addition, for obtaining the intrinsic noise sources of devices, noise parameters(minimum noise figure $F_{min}$, equivalent noise resistance $R_n$ optimized source admittance $Y_{opt}=G_{opt}+B_{opt}$) in submicron MOSFETs is extracted. With this extraction method, the intrinsic noise parameters of MOSFET without effects of probe pad and extrinsic parasitic elements from RF noise measurements can be directly obtained.

Optimal design of a flexure hinge-based XY AFM scanner for minimizing Abbe errors and the evaluation of pitch measuring uncertainty of a nano-accuracy AFM system (XY 스캐너의 아베 오차 최소화를 위한 최적 설계 및 나노 정밀도의 원자 현미경 피치 측정 불확도 평가)

  • Kim Dong-Min;Lee Dong-Yeon;Gweon Dae-Gab
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.6 s.183
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    • pp.96-103
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    • 2006
  • To establish of standard technique of nano-length measurement in 2D plane, new AFM system has been designed. In the long range (about several tens of ${\mu}m$), measurement uncertainty is dominantly affected by the Abbe error of XY scanning stage. No linear stage is perfectly straight; in other words, every scanning stage is subject to tilting, pitch and yaw motion. In this paper, an AFM system with minimum offset of XY sensing is designed. And XY scanning stage is designed to minimize rotation angle because Abbe errors occur through the multiply of offset and rotation angle. To minimize the rotation angle optimal design has performed by maximizing the stiffness ratio of motion direction to the parasitic motion direction of each stage. This paper describes the design scheme of full AFM system, especially about XY stage. Full range of fabricated XY scanner is $100{\mu}m\times100{\mu}m$. And tilting, pitch and yaw motion are measured by autocollimator to evaluate the performance of XY stage. As a result, XY scanner can have good performance. Using this AFM system, 3um pitch specimen was measured. The uncertainty of total system has been evaluated. X and Y direction performance is different. X-direction measuring performance is better. So to evaluate only ID pitch length, X-direction scanning is preferable. Its expanded uncertainty(k=2) is $\sqrt{(3.96)^2+(4.10\times10^{-5}{\times}p)^2}$ measured length in nm.

A Two-Axis Ultra-precision Stage Using Flexure-type Parallel Linear Guide Mechanism (플렉셔 구조의 병렬형 선형 안내기구를 이용한 2 축 초정밀 스테이지)

  • Choi Kee-Bong
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.1 s.178
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    • pp.129-135
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    • 2006
  • In this study, a two-axis ultra-precision stage driven by piezoelectric elements is presented. The stage has a flexure-type parallel linear guide mechanism consisting of quad-symmetric simple parallel linear springs and quad-symmetric double compound linear springs. While the simple parallel linear springs guide the linear motion of a moving plate in the stage, the double compound linear springs follow the motion of the simple parallel linear spring as well as compensate the parasitic motions caused by the simple parallel linear springs. The linear springs are designed by rectangular beam type flexures that are deformed by bending deflection rather than axial extension, because the axial extension is smaller than the bending deflection at the same force. The designed guide mechanism is analyzed by finite element method(FEM). Then two-axis parallel linear stage is implemented by the linear guide mechanism combined with piezoelectric elements and capacitance type displacement sensors. It is shown that the manufactured ultra-precision stage achieves 3 nm of resolution in x- and y-axis within 30 ${\mu}m$ of operating range.

Analysis and Design of 3-DOF Parallel Mechanism Based on Kinematic Couplings (기구학적 커플링으로 구성된 3자유도 병렬 메커니즘 해석 및 설계)

  • Wang, Wei-Jun;Han, Chang-Soo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.3
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    • pp.479-486
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    • 2012
  • This paper presents a high-speed automatic micro-alignment system that is a part of an inspection machine for small-sized molded lenses of mobile phones, palm-top computers, and so on. This work was motivated by the shortcomings of existing highest-grade commercial machine. A simple tip/tilt/Z parallel mechanism is designed based on kinematic couplings, which is a 3-degree-of-freedom (3-DOF) moderate-cost alignment stage. It is used to automatically adjust the posture of each lens on the tray, which is impossible by the conventional instrument. Amplified piezoelectric actuators are used to ensure the accuracy and dynamic response. Forward kinematic analysis and simulation show that the parasitic motion is small enough compared to the actuator stroke. From the workspace analysis of the moving platform, it is clear that the output motion range satisfies the design requirements.