Electrical generator or motor structure – Dynamoelectric – Linear
Reexamination Certificate
1999-11-30
2003-04-29
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Linear
Reexamination Certificate
active
06555936
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
1. Industrial Field of the Invention
The present invention relates to a flat motor and an exposure device, and more particularly, to a flat motor for driving a moving element (slider) two-dimensionally by electromagnetic force and to an exposure device using the flat motor for a substrate stage unit.
2. Description of the Related Art
Conventionally, exposure devices are used in a lithography process for manufacturing semiconductor devices, liquid crystal devices and the like to transfer a pattern formed on a mask or a reticle (hereinafter, generically called “reticle”) onto a substrate such as a wafer, a glass plate or the like, on which a resist of the like is coated, through a projecting optical system.
In the exposure device, a wafer is held on a wafer holder by vacuum adsorption or the like because it must be positioned at an exposing position with pinpoint accuracy, and the wafer holder is secured on a wafer table.
Conventionally, a drive unit composed of a rotating type motor and a conversion mechanism for converting a rotating motion to a linear motion is often used as a drive unit for moving an object to be controlled such as the wafer table and the like on a straight line or a plane or positioning the object at a target position. Recently, however, a stage unit has been developed for positioning an object to be controlled by driving it two-dimensionally in a contact-free fashion so that the object to be controlled can be positioned at a higher speed with pinpoint accuracy without being affected by the accuracy of a mechanical guide surface and the like and that the life of the stage unit can be increased by the avoidance of mechanical friction. A variable-magnetic-resistance drive type flat motor is known as the drive source of the non-contact drive type stage unit.
At present, the variable-magnetic-resistance drive type flat motor is mainly arranged by coupling the two axes of variable-magnetic-resistance drive type linear pulse motors as in a Sawyer motor. The variable-magnetic-resistance drive type linear pulse motor includes a stator, which is composed of a sheet-shaped magnetic body having, for example, uneven tooth portions formed thereon along a lengthwise direction at equal intervals and a slider, which is composed of a plurality of armature coils confronting the uneven tooth portions of the stator, having uneven portions whose phase is different from that of the above uneven tooth portions and coupled through permanent magnets. Then, the slider is driven making use of force generated so as to minimize a magnetic resistance between the stator and the slider at each timing. That is, the slider is advanced stepwise by regulating and controlling the current values and the phases of pulse currents supplied to the respective armature coils.
PROBLEMS TO BE SOLVED BY THE INVENTION
In the variable-magnetic-resistance drive type flat motor, it is necessary to obtain large drive force to realize positioning at a high speed by using it in a precise positioning unit. For this purpose, a large current must be necessarily flown to armature coils. As a result, a large problem is arisen in the heat generated from the armature coils.
However, since the armature coils are not cooled in the variable-magnetic-resistance drive type flat motor at present, it is difficult to apply the flat motor to the precise positioning unit.
Further, there has been also developed a flat motor which is obtained by two-dimensionally developing a linear motor and driven by Lorentz electromagnetic force (for example, U.S. Pat. No. 5,196,745). It is said that the Lorentz electromagnetic-force type flat motor is promising as a stage drive source in future because it is excellent in controllability, thrust force linearity and positioning characteristic.
However, a large current must be flown to armature coils also in the Lorentz electromagnetic-force flat motor to obtain a large amount of thrust force and thus the armature coils act as a heat generating source. Therefore, the environment of a precise positioning device is taken into consideration, it is indispensable to design a cooling system to realize a flat motor in which a thermal effect is lowered.
Further, in the Lorentz electromagnetic-force-drive flat motor and the like, an armature unit including armature coils is usually arranged as a stator for the convenience of supplying a current to the armature coils. However, when the flat motor arranged as described above is employed as the drive source of the substrate stage of a projecting/exposing device including a projecting optical system, the stator is often physically secured to a main body column by which the projecting optical system is held. In this case, the projecting optical system is oscillated by the reaction force acting on the stator when a slider is driven, which results in the dislocation of a position to which a pattern is transferred and the deterioration of uniformity of a line width. However, since the exposure device using the flat motor is now at the start of its development, a mechanism for not transmitting the reaction force acting on the stator such as the armature unit and the like to a structural member for supporting it is not yet known.
A first object of the present invention, which was made in the above circumstances, is to provide a flat motor cable of suppressing a thermal effect on a peripheral environment.
A second object of the present invention is to provide an exposure device capable of carrying out exposure with pinpoint accuracy while maintaining a high throughput.
MEANS FOR SOLVING THE PROBLEMS
A flat motor device according to the invention described in claim
1
is characterized by comprising a moving unit (
40
,
42
) moving along a predetermined moving surface; and a fixed unit (
32
) having the moving surface formed on the side thereof confronting the moving unit, wherein one of the moving unit and the fixed unit includes a pole unit (
40
); and the other of the moving unit and the fixed unit includes armature coils (
32
), a heat insulating chamber (
62
) disposed to the armature coils on the moving surface side thereof and a cooling chamber (
64
) disposed to the armature coils on the side thereof opposite to the moving surface.
According to the flat motor device, when currents are supplied to the armature coils constituting the moving unit or the fixed unit, the moving unit is moved along the moving surface by the electromagnetic force generated by electromagnetic interaction between the armature coils and (the magnets constituting) the pole unit. When the moving unit is to be continuously moved in a certain direction, currents are supplied to the armature coils which confront the pole unit (magnets) (in the case of a moving magnet type) or to all the armature coils (in the case of a moving coil type) in accordance with the moving position of the moving unit. With this operation, the armature coils to which the respective currents are supplied generate heat. In this case, the heat insulating chamber is disposed to the armature coils on the moving surface side thereof and the cooling chamber is disposed thereto on the side thereof opposite to the moving surface, respectively. As a result, the transmission of the heat generated by the armature coils to the moving surface side is suppressed or prevented by the heat insulating action of the heat insulating chamber, and the armature coils are cooled by the cooling chamber. Therefore, the armature coils can be cooled as well as the effect of the heat generated by the armature coils on a peripheral environment can be suppressed.
In this case, various types of heat insulating and cooling methods can be contemplated and various arrangements of the heat insulating chamber and the cooling chamber can be contemplated accordingly. For example, as shown in the invention described in claim
2
, the interiors of the heat insulating chamber (
62
) and the cooling chamber (
64
) may be arranged as flow passages in which fluids having different flow conditions flow. In this case, th
Hazelton Andrew
Tanaka Keiichi
Jones Judson
Nikon Corporation
Oliff & Berridg,e PLC
Ramirez Nestor
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