The assignee for this patent application is Canon Kabushiki Kaisha.
Reporters obtained the following quote from the background information supplied by the inventors: "The present invention relates to a stage apparatus, a lithography apparatus, and a method of manufacturing an article.
"A lithography apparatus employed to manufacture a semiconductor device or a liquid crystal device performs a process (for example, exposure) of positioning a substrate held by a substrate stage to transfer a pattern onto the substrate. In the lithography apparatus, to keep up with miniaturization of the pattern to be transferred onto the substrate, the substrate stage is formed by a fine moving stage and coarse moving stage to attain highly accurate substrate positioning.
"The fine moving stage which constitutes the substrate stage generally includes a fixed portion, a movable portion arranged on the fixed portion, and a linear motor serving as a driving unit which drives the movable portion, as disclosed in International Publication No. 2011/074962. The linear motor exhibits excellent response characteristics and vibration insulation properties, but disadvantageously generates a large amount of heat when it generates a force (that is, during its operation). Hence, the weights of the substrate and movable portion are supported by a spring element (elastic body) such as a coil spring without supporting them by the linear motor (without generating a force).
"Also, a chuck which holds the substrate is mounted on the movable portion in the fine moving stage. Hence, when the substrate or chuck is removed from the movable portion in, for example, exchanging the substrate or chuck, the weights supported by the spring element decrease, so the movable portion ascends by the force of the spring element. Under the circumstance, in International Publication No. 2011/074962, a mechanical stopper for stopping the movement of the ascending movable portion by abutting against it (that is, for regulating its position in the Z-direction) is disposed on the fine moving stage. This is because heat generated by the linear motor becomes problematic when a force of the spring element that acts to lift the movable portion is canceled using, for example, the linear motor which drives the movable portion (that is, when a force which cancels that of the spring element which acts to lift the movable portion is generated by the linear motor).
"Unfortunately, as in the conventional technique, when the movement of the movable portion is stopped by abutting it against the mechanical stopper, a play is set between the mechanical stopper and the movable portion, so the reproducibility of the attitude of the movable portion and, especially, its position in a rotation direction about the Z-axis (.omega.z-direction) degrades. In addition, wear of the mechanical stopper by repetitions of abutment of the movable portion leads to degradation in reproducibility of the attitude of the movable portion. As a result, it becomes difficult to accurately align the movable portion and chuck in mounting the chuck on the movable portion."
In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "The present invention provides a technique advantageous in controlling the position of a movable portion of a stage apparatus.
"According to one aspect of the present invention, there is provided a stage apparatus which holds a substrate, the apparatus comprising: a fixed portion; a movable portion which is arranged on the fixed portion, and on which a substrate holder that holds the substrate is mounted; a driving unit which includes a first coil arranged on the fixed portion, and a first magnet which is arranged on the movable portion and opposed to the first coil, and is configured to move the movable portion by a magnetic field generated by supplying a current to the first coil; a spring element configured to support the movable portion to set the movable portion at a reference position while the substrate holder that holds the substrate is mounted on the movable portion; and an attracting unit which includes a first yoke arranged on the fixed portion, and a second coil wound around the first yoke, and is configured to attract the movable portion to a side of the fixed portion by a magnetic field generated by supplying a current to the second coil, wherein the attracting unit attracts the movable portion to the side of the fixed portion to set the movable portion at the reference position after at least one of the substrate and the substrate holder is removed from the movable portion.
"Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
"FIG. 1 is a schematic view showing the configuration of a lithography apparatus according to an aspect of the present invention.
"FIG. 2 is a schematic view showing the configuration of a fine moving stage of a stage apparatus in the lithography apparatus shown in FIG. 1."
For more information, see this patent application: Kii,
Keywords for this news article include: Physics, Linear Motor, Canon Kabushiki Kaisha.
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