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Linear motors have been widely used in lithography, which are usually realized with optomechanical devices called a wafer scanner. Linear motors can provide both large travel range and precise motion. Nonlinear back lash and contact friction effects are also avoided with direct drive linear motors supported by air bearings or electromagnetic levitation. In this paper, a linear motor using Halbach magnet arrays are used. By using a Halbach magnetic array, the magnetic flux on one side of the array is reinforced while the flux is canceled on the other, allowing for a stronger force for equal current compared with a conventional north-south magnet array configuration. Using Halbach linear motors, long range nano-precision positioning have been designed and demonstrated with the use of laser inteferometer feedback sensing.



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