Development of Friction Drive System and Intelligent Linear Guide for Nanometer Positioning

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A high precise of the order of nanometer and high speed positioning must be necessary in order to achieve a high accuracy and high throughput productivity for the next generation of LSI (large scale integrated circuit). The purpose of this research was establishment of a friction drive system with ultrasonic motor for nanometer positioning to reply these requirements. As a result of this investigation, new monitoring method was established to predict and to control wear mode of the ultrasonic motor. Further new technology was introduced to control wear particles which affect position accuracy degradation of the precise positioning stage. The conclusions obtained in this investigation are described as follows ;1.The amount of fluctuation of operating voltage Ef was proposed as a monitoring parameter of severity of contact between drive tip and driven rail. It was clarified that the transition between mild wear and severe wear could be predicted by using Ef values.2.It was clarified both experimentally and theoretically that electrostatic force accounts for most part of the total adhesive force of wear particles at the contact interface. In the case of Al_2O_3 tip, electrostatic force applied to wear particles of the order of 1 μm is 505 times larger than van der Waals force.3.Position accuracy was kept stable and by using Al_2O_3 base composite as tip material of the ultrasonic motor and air blow with electric discharge in to the friction interface. The life of the stage was increases as much as 530 times, compared with the stage life without wear particle removal and by using Al_2O_3 tip.