Invited Speaker
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Prof. Kuang-Chao Fan |
| National Taiwan University | |
Abbé Error Compensation in Positioning Stages |
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| Abstract: Most positioning stages do not observe the law of Abbé principle due to the limitation in structural design. Angular errors of the moving stage will induce the positioning difference of the functional point and the measured feedback point. This paper addresses the influence of Abbé errors on general machine tools. A multi-sensor feedback compensation strategy is proposed to compensate for the volumetric errors of the machine tool. The built-in three-angle sensor is designed and equipped in each axis. An embedded microprocessor is developed to compensate the volumetric errors in real time. Experiments show that the positioning errors of machine tool can be significantly improved after error compensation. The principle of free of Abbé error design is also proposed for a long-stroke and nanopositioning co-planar stage, which can be used in micro/nano measurement and machining. Download Abstract | |
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Prof. Seung-Woo Kim |
| Korea Advanced Institute of Science and Technology (KAIST) | |
Advanced Metrology for Space Missions using
Femtosecond Lasers |
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| Abstract: Femtosecond lasers offer unique characteristics in both the temporal and spectral terms, not observed in other continuous-wave or pulse lasers, permitting breakthroughs in precision metrology particularly in time, distance and spectroscopy. Motivated by the technological stimulus brought about since the advent of femtosecond lasers, much attention is being drawn to extend today’s space missions by improving the precision of remote sensing and control capabilities. In this keynote, we introduce how femtosecond lasers are being exploited for the purpose of space exploration in the near future. Special emphasis is given to address the state-of-the-art developments on absolute distance measurement, multi-functional spectroscopy, time transfer and optical clock, which will be soon realized with enhance resolutions and ranges for the next generation space missions. Download Abstract | |
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Dr. Susumu Makinouchi |
| Nikon corporation, Japan | |
The History of Exposure-tool Stages for the Semiconductor Manufacturing |
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| Abstract:
For many years the precision moving stage was a key element of the lithography exposure tool for semiconductor manufacturer. In late 70s the line width of high-end LSIs was around 4µm. Today the one became 20nm range. Moreover, the increasing of productivities are more surprising, from 20 wph (wafer per hour) in 4inch wafers in 70’s to 150 wph in 12inch wafers in today’s industry. In this talk, we would like to look back on the history of the stage for the exposure machines. In late 70s the early days of wafer steppers, we usually used grease-lubricated-screw-driven stages for the machine. Its top speed was about 50mm/s and maximum acceleration was 0.05g. Acceptable positioning accuracy was around 0.1µm in this age. Through 80’s we had concentrated on increasing the throughput and accuracy of the screw-driven stages. However, in early 90s the development of scanning exposure machines had begun. For scanning exposure, the smoothness of high speed motion is the most important. In order to achieve the high order smoothness, we started to use the linear-motor-driven-air-bearing stage. These changes demanded higher stiffness than ever before to the mechanical system. In addition, the large reticle stage which are required for the scanning exposure forced to renew the overall body structure. In the early 2000s, our next challenge was the immersion exposure machine. Though it is too complicated to explain in this abstract, it required the tandem stages which work highly controlled collaborative motion to avoid any leakage of water. Technology has been greatly changed in this way. However, the philosophy that required for engineers has not changed much. It is to understand the whole system required, and to lead to optimal mechanical structure, then, to find out control method appropriate to it. We hope the talk will contribute somehow for future technologies. Download Abstract |
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Prof. Koichi Oka |
| Kochi University of Technology | |
Noncontact Positioning Control System
Using Permanent Magnet |
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| Abstract: This paper paper describes noncontact suspension and position control system using linear actuated permanent magnets. The suspension system uses unique suspension mechanism whose suspension force is mechanically controlled by air gap length. This mechanism is composed of permanent magnets, gap sensors, and linear actuators. In this paper, the various suspension systems and position control systems are introduced. Those mechanisms, appearances, control systems, and experimental results are shown. Download Abstract | |