A High-Precision Positioning System Using Magnetic Levitation∗

High accuracy positioning stages with multiple degrees-of-freedom are ubiquitous in industrial manufacturing. Examples include probing and inspection systems, disk drive head assembly systems, and photolithographic positioning stages (microsteppers) in semiconductor manufacturing. Microsteppers are typically made of a lower-stage that actuates large high-speed movements and an upper-stage that delivers high-precision movements using piezoelectric actuators [1]. One of the main drawbacks of mechanical positioning actuators in semiconductor manufacturing is that mechanical contacts introduce impurities limiting the accuracy of the photolithographic process, thus reducing production throughput. Furthermore, mechanical positioning devices require costly maintenance due to the wear of their components. These problems become critical as the pace of technology causes the overall dimensions of semiconductors to further decrease. For these reasons, there is an increasing interest, in industry, to replace mechanical microsteppers by contactless positioning devices. While high-precision contactless positioning devices have obvious application in semiconductor manufacturing, it is also clear that they could be used in any area where speed and ∗This research was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canada Foundation for Innovation (CFI)