Laser beam cutting (LBC) is a non-contact machining method that is widely used in industry. In order to improve cutting speed and reduce the consumption of assist gas, it is necessary to employ a machining method that applies a suitable eccentricity between the laser beam axis and the assist gas nozzle axis. This paper describes the development of a high-speed, high-precision, magnetic drive actuator, which can be attached to a conventional LBC machine to control the relative displacement between the laser beam axis and the assist gas nozzle axis in two orthogonal directions. First, a magnetic drive actuator is designed and fabricated. In the actuator, the motions of the lens in the radial directions are controlled by electromagnets, and the motions in the other directions are constrained by elastic hinges. Second, a compensation method for the zero point of the displacement sensors that are used to measure the displacements of the lens in the radial direction and an adaptive control method for the actuator are presented. Finally, the effectiveness of the presented control method is verified, and the positioning performance of the actuator is evaluated through experiments. The experimental results showed that the vibration of the lens was reduced using the presented control method, and the actuator had a positioning resolution of 0.75 µm, a bandwidth greater than 133 Hz, and a positioning stroke of 1 mm.
A step-like decrease of the output energy of an ArF excimer laser for microlithography has been observed during highrepetition rate and high-power operation. The reason for the step-like energy decrease was traced to oxygen by adding 50 ppm of various gas impurities to the laser gas. It is supposed that the energy decrease is caused by laser light absorption due to the oxygen or to some kinds of oxygen compounds because no change was observed in ArF and XeF emission intensities which were monitored as measures of excimer formation, Xe content, and discharge states.
This paper describes an adaptive control method for a magnetic drive actuator that used for the laser cutting to realize high speed and high accuracy machining. Firstly, a zero bias current method and a nonlinear compensator are examined and used for the actuator. Secondly, an adative control method is presented. Finally, the coefficient of the gap-current-force is estimated and the effectiveness of the presented control method is verified by experiments. The experimental results show that the coefficient of the gap-current-force reduces exponentially depending on the increase in the length of the air gap. By using the adaptive control, the peak-to-peak vibration amplitude of the lens holder is reduced from 1.95um to 1.55um.
This paper describes an adaptive control method fbr a magnetic drive actUator that used fbr the laser cutting tQ realize high speed and high accuracy machining . Firstly , a zero bias。urrent method and a nenlinear cempensator are examined and used fbr 廿1e actuator . Secondly , an adaptive control method is presented 、 Finally , the coefficient of the gap −current −fbrce is estirnated and the effectiveness of the presented control methed is verified by experiments . The experirnentaL results shew that the coef 五cient ofthe gap − current − fbrce reduces exponentially depending on 出 e increase in the length ofthe air gap, By using the adaptive control , the peak − to − peak vibratien amplitude ofthe lens holder is reduced from l. 95 μ m to l55 μ m . Moreover, the
A steplike decrease in the output energy of an ArF excimer laser for microlithography is caused by the laser light absorption in the laser gas. To identify the absorbing gas component, the light absorption characteristics of the laser gas inside the discharge chamber were investigated under various gas conditions using a continuous xenon light source in the ultraviolet region and an ArF excimer laser at 193 nm. As a result, the oxygen-fluorine compound F x O y generated in the laser discharge was identified as the absorbing molecule, because a strong steplike absorption of the 193 nm laser light was only observed when oxygen and fluorine were added together to the discharge gas. The lifetime of this absorbing molecule was examined against gas temperature during the operation of the laser discharge. The data obtained were useful in setting the best operational conditions for the ArF excimer laser for microlithography.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.