Levitational and Vacuum-Compatible Micro Conveyer Utilizing the Meissner Effect of Ceramic Superconductor

本课题的研究目的是研制一种在真空环境下悬浮和携带小型物体的微型装置。利用超导体和永磁体之间的排斥力实现了无主动控制的稳定悬浮。该器件的一个可能应用是用于半导体集成电路制造的群集真空装置中的晶圆输送机。通过非接触的悬浮运动可以避免滑动表面产生的颗粒污染。此外，在微型机械中占主导地位的摩擦力也可以通过悬浮来消除。通过使用微加工工艺实现了器件的小型化。结果表明：(1)设计了一种悬浮执行器，该执行器由带永磁体的滑块、具有排斥力的超导体和超导上载流驱动滑块的线电极组成。因此，该装置是磁斥力悬架和直线同步步进电机的结合。通过对永磁体和驱动电极的优化布置，获得了最大的悬浮力和驱动力，同时又有足够的定位精度。实验测定了不同类型超导体与磁体之间的排斥力和阻力；结果表明，基于陶瓷的超导体最适合于该器件。(2)为了实现X-Y双向运动，我们在绝缘膜上设置两组线电极，并将其正交放置在超导体上。线条的间距为0.18 mm。滑块有四个1毫米的磁铁。采用真空环境下的闭环冷却装置对超导体进行冷却。在真空中成功地进行了驱动实验。当电流大于500ma时，滑块逐步移动；一步为0.18 mm。确定了二自由度运动。滑块的瞬时速度为33 m/s，每步沉降时间为20 ms。(3)通过上述实验，该装置达到了真空装置中输送机的基本要求。少

The purpose of this research is develop a micro miniature device to levitate and carry a small object in vacuum environment. The stable levitation without active control was achieved by using the repulsive force between a superconductor and a permanent magnet. One possible application of the device is the wafer conveyer in a clustered vacuum apparatus for semiconductor IC fabrication. Contamination by particles generated in sliding surfaces can be avoided by the non-contact movement with levitation. Furthermore friction force which is dominant in micromachines can also be eliminated by levitation. Miniaturization of the devices was achieved by using micromaching processes. Following results are obtained:(1) We designed the levitational actuator which was composed of a slider with permanent magnets, a superconductor for repulsive force, and line electrodes on the superconductor for carrying current to drive the slider. Therefore the device was the combination of both the magnetic repuls … More ive suspension and the linear synchronous stepping-motor. Through the optimal arrangement of permanent magnets and driving electrodes, we obtained the maximum levitation force and driving force while having enough accuracy in positioning. The repulsive force and the drag force acting between different kinds of superconductors and the magnet were determined experimentally; the result suggested a Y-based ceramic superconductor was most suitable to this device.(2) In order to achieve X-Y two directional movement, we have two sets of line electrodes on insulation films and placed them orthogonally on the superconductor. The pitch of the lines was 0.18 mm. The slider had four magnets of 1 mm cub. The superconductor was cooled by closed loop cooling set-up for vacuum environment. Driving experiments were successfully carried out in the vacuum. With currents over 500 mA, the slider moved step by step; one step was 0.18 mm. Two-degree-of -freedom movement was confirmed. Instantaneous speed of the slider was 33 m/s and the settling time for a step was 20 ms.(3) From the above experiment it was concluded that the device cleared basic requirements for a conveyer in vacuum apparatus. Less