Electrical generator or motor structure – Dynamoelectric – Linear
Reexamination Certificate
1998-06-23
2001-06-26
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Linear
C355S053000, C355S072000
Reexamination Certificate
active
06252314
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
This invention relates to a linear motor and a stage system for high precision positioning or scan motion. In another aspect, the invention is concerned with a scanning exposure apparatus using such a stage device. In a further aspect, the invention is directed to a device manufacturing method suitable for the manufacture of microdevices by use of a scanning exposure apparatus described above.
Among exposure apparatuses for use in semiconductor device production, scan type exposure apparatuses become attractive because of their large exposure area. This type of exposure apparatus comprises an exposure optical system for projecting a a semiconductor device pattern formed on a reticle onto a semiconductor substrate coated with a photosensitive material, a reticle stage for scanningly moving the reticle, and a wafer stage for scanningly moving the wafer. These stages perform scan movement. For the scan movement, the positional relation between the stages is controlled precisely to prevent blur or distortion of the image of the reticle pattern as formed on the wafer through the exposure optical system. The stage position is measured by use of a measuring system having a laser interferometer. A stage driving system may comprise an electromagnet type linear motor having good controllability.
FIG. 11
is a schematic view for explaining an example of a stage device having a linear motor. There are movable elements
101
disposed on the opposite sides of a stage movable portion on which a workpiece
100
such as a reticle is placed. They are mounted on a guide
192
. Stators
103
are disposed at positions corresponding to the movable elements
101
, respectively, while being kept out of contact thereto. Each stator
103
comprises a plurality of coils
104
, being stator elements arrayed along the movement direction, and a stator frame
105
for supporting the coils. The movable element
101
comprises a magnet
106
and a yoke
107
. In response to a supply of electric current to coils
104
, a thrust is produced at the movable element
101
. With the movement, coils to be energized by electric current are changed sequentially, whereby the movement stroke is enlarged and a required movement stroke is provided.
In the illustrated stage device, the scan movement is made only in one direction. With respect to directions other than the movement direction, guide means such as an air bearing is used for the confinement.
When a stage device such as shown in FIG.
11
is applied to a reticle stage of a scan type exposure apparatus, the position of a reticle other than in the scan movement direction, or the straightness thereof, is determined by the shape of a guiding surface of guiding means, for example. Namely, since a reticle is confined by the guide means with respect to directions other than the movement direction, the positioning precision with respect to those directions is restricted by the mechanical performance of the guide means.
In scan movement for scanning exposure, it is important to assure registration between motion of a projected image of a reticle pattern and motion of a wafer, within a certain error range. If there is a large misregistration between the motion of the projected image and the motion of wafer, a blurred pattern image will be transferred to the wafer or a generally distorted pattern shape is transferred thereto.
In consideration of the above, during scan movement in an exposure operation, the relative positional relation between a reticle stage and a wafer stage has to be controlled within a predetermined high precision range. How it can be improved is a factor for improving the performance of a scan type exposure apparatus.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a linear motor or a stage device having good straightness and being suitable for use in a scan type exposure apparatus.
It is another object of the present invention to provide a scan type exposure apparatus having such a stage device, by which enhanced exposure transfer precision is assured.
In accordance with an aspect of the present invention, there is provided a linear motor for scanningly moving a movable element relative to a stator and for a predetermined stroke, wherein the linear motor includes electromagnetic means for producing a drive force for displacing the movable element in a scan direction and also in a direction perpendicular thereto.
The stator may have first coils disposed along the scan direction and one or more second coils disposed separately from the first coils.
The movable element may have first magnet means disposed along the scan direction, and second magnet means disposed along a direction perpendicular to the scan direction.
In accordance with another aspect of the present invention, there is provided a stage system which comprises a linear motor such as described above, for moving a movable stage.
In accordance with a further aspect of the present invention, there is provided a scanning exposure apparatus for projecting a portion of a pattern of a reticle onto a wafer and for scanningly moving the reticle and the wafer, thereby to transfer the reticle pattern onto the wafer, wherein the apparatus comprises a reticle stage for scanningly moving the reticle, having the structure such as described above.
A device manufacturing method for manufacturing devices by use of a scanning exposure apparatus such as described above is within the scope of the present invention.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3376578 (1968-04-01), Sawyer
patent: 5767948 (1998-06-01), Loopstra et al.
patent: 5789892 (1998-08-01), Takei
patent: 5841250 (1998-11-01), Korenage et al.
patent: 5844666 (1998-12-01), Van Engelen et al.
patent: 5850280 (1998-12-01), Ohtomo et al.
patent: 5953105 (1999-09-01), Van Engelen et al.
patent: 6084319 (2000-07-01), Kamata et al.
patent: 0 421 527 (1991-10-01), None
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Jones Judson H.
Ramirez Nestor
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