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We present a six-axis magnetic-levitation (maglev) stage capable of precision positioning down to several nanometers. This stage has a simple and compact mechanical structure advantageous to meet the performance requirements in the next-generation nanomanufacturing. It uses the minimum number of linear actuators required to generate all six axis motions. In this paper, we describe the electromechanical design, modeling, and control, and the electronic instrumentation to control this maglev system. The stage has a light moving-part mass of 0.2126 kg. It is capable of generating translation of 300 μm in the x, y, and z axes, and rotation of 3 mrad about the three orthogonal axes. The stage demonstrates position resolution better than 5 nm rms and position noise less than 2 nm rms. Experimental results presented in this paper show that the stage can carry, orient, and precisely position a payload as heavy as 0.4 kg. The pull-out force was found to be 8.08 N in the vertical direction. Furthermore, under a load variation of 0.14 N, the nanopositioner recovers its regulated position within 0.6 s. All these experimental results match quite closely with the calculated values because of the accurate plant model and robust controller design. This device can be used as a positioning stage for numerous applications, including photolithography for semiconductor manufacturing, microscopic scanning, fabrication and assembly of nanostructures, and microscale rapid prototyping.
Date of Publication: Sept.-Oct. 2005