2001 Fiscal Year Final Research Report Summary
DEVELOPMENT OF AEROSTATIC BEARINGS FOR HIGH SPEED PRECISION POSITIONING MECHANISM IN HIGH VACUUM CHAMBER
| Project/Area Number |
12650147
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
設計工学・機械要素・トライボロジー
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| Research Institution | TOKYO UNIVERSITY OF SCIENCE |
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Principal Investigator |
SHIGEKA YOSHIMOTO TOKYO UNIVERSITY OF SCIENCE FACULTY OF ENGINEERING PROFESSOR., 工学部, 教授 (80096718)
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| Project Period (FY) |
2000 – 2001
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| Keywords | AEROSTATIC BEARING / GAS BEARING / VACUUM CHAMBER / POSITIONING TECHNOLOGY / VISCOUS SEAL |
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| Research Abstract |
It is said that the minimum width of a circuit line in DRAM will be less than 0.1nm in near future and that EB and EUV will be used for lithography, judging from the resolution of ArF and Fa. It is also in the next generation of DVD with 30 GBit memory said that EB lithography will be used for making the original recording disk. In order that EB lithography establishes the same order of production rate as the laser beam lithography does, it is needed to develop the precision positioning mechanism which can move with acceleration of several times of gravity in high vacuum chamber. In this study, we propose a newly developed aerostatic bearing available to high vacuum chamber. This bearing has several steps of viscous seals between an aerostatic bearing and a vacuum chamber. In addition, a vacuum pump is connected to each space between seals to pump out air. This mecha-nism can prevent the air from entering a vacuum chamber, and high degree of vacuum of a chamber can be obtained. The vacuum degree of the chamber with this type of aerostatic bearing is numerically calculated and the design method of exhaust system including vacuum pumps and viscous seals is discussed. Furthermore, the theoretical results were compared with the experimental results to confirm the validity of theoretical predictions. As a result, the following conclusions were drawn. (1). Using Reynolds equation taking into account the slip flow, the vacuum degree of a vacuum chamber was accurately predicted. (2). Three-step viscous seal system can reduce the vacuum degree of a vacuum chamber to the order of 10^<-4>Pa. (3). When the shaft moves in the axial direction, the vacuum degree of the chamber is decreased due to evaporative objects on the shaft surface.
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