Electrical generator or motor structure – Dynamoelectric – Linear
Reexamination Certificate
2002-03-26
2004-07-13
Mullins, Burton S. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Linear
C355S053000, C355S072000
Reexamination Certificate
active
06762516
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electromagnetic actuator such as a linear motor having stationary and movable elements and, more particularly, to an exposure apparatus having the electromagnetic actuator, a device manufacturing method using the exposure apparatus, a device manufacturing factory where the exposure apparatus is installed, and a maintenance method for the exposure apparatus.
BACKGROUND OF THE INVENTION
Typical, conventional exposure apparatuses used for the manufacture of various devices, such as a semiconductor device, are a step and repeat exposure apparatus (also called a stepper) for sequentially exposing a plurality of exposure regions on a substrate with the pattern of a master (reticle or mask) while stepping the substrate (wafer or glass substrate), and a step and scan exposure apparatus (also called a scanner) for repeating step movement and scanning exposure to repetitively expose a plurality of regions on a substrate. In particular, the step and scan exposure apparatus uses only a light component relatively close to the optical axis of a projection optical system by restricting a light beam through a slit. This type of exposure apparatus enables higher-precision exposure of a fine pattern with a larger field angle.
These exposure apparatuses comprise stage devices (wafer stage and reticle stage) for moving a wafer and reticle at high speed and aligning them. A general stage driving method adopts a linear pulse motor (linear motor) using the Lorentz force. The use of the linear motor realizes high-speed driving of the stage movable and stationary portions in non-contact with each other and high-precision alignment.
The stage acceleration along with higher-speed (higher-throughput) alignment processing increases more and more. For example, in the step and scan exposure apparatus, the maximum stage acceleration reaches 5×9.81 m/s
2
(5G) for the reticle stage and 1×9.81 m/s
2
(1G) for the wafer stage. The driving force defined by <mass of moving member>×<acceleration> becomes very large. This also increases the heat generation amount of a stage driving linear motor, and generated heat is seriously influencing the surroundings. To suppress heat generated from a coil, a coolant has conventionally been caused to flow near the coil. The coolant flowing method includes a method of cooling only a coil support, as shown in
FIGS. 6A and 6B
, and a method of cooling the entire coil, as shown in
FIGS. 7A and 7B
. A linear motor shown in
FIGS. 6A and 6B
and a linear motor shown in
FIGS. 7A and 7B
schematically represent a linear motor in which a coil
4
is attached to a stationary element
1
to drive a movable element
2
.
FIGS. 6A and 7A
are plan views, and
FIGS. 6B and 7B
are sectional views taken along the lines D-D′ and E-E′, respectively. In
FIGS. 6A and 6B
, a coolant channel
32
is formed partially inside a coil support
33
, which partially supports the coil
4
, and only the coil support
33
is cooled. In this method, the coil
4
is exposed at portions other than the portions where the coil
4
is supported by the coil support
33
, and heat greatly influences the surroundings. In
FIGS. 7A and 7B
, a coolant channel
32
is formed entirely inside a coil support
33
which supports a whole coil
4
, and the whole coil
4
is cooled. In this method, heat less influences the surroundings, compared to the method of cooling only the coil support, as shown in
FIGS. 6A and 6B
. However, a relatively large temperature difference is generated between the upstream and downstream of the cooling coolant. The surface temperature of the linear motor cannot be made uniform, and the temperature difference influences the surroundings.
The conventional manufacturing process of a semiconductor element such as a VLSI formed from an ultrafine pattern employs a reduction type projection exposure apparatus for projecting a circuit pattern drawn on a mask onto a substrate coated with a photosensitive agent and printing the pattern. With an increase in the mounting density of a semiconductor element, demand has arisen for further micropatterning, and the exposure apparatus is coping with micropatterning.
To achieve high-speed alignment by using the linear motor capable of high-precision alignment, a large driving force must be generated. For this purpose, a large current must be caused to flow through the coil. Causing a large current to flow further increases the heat generation amount of the coil.
In general, a semiconductor exposure apparatus uses an interferometer for high-precision alignment. However, heat generated from a coil increases and fluctuates the temperature near a linear motor or in a stage space where the optical axis of the interferometer and a mirror are installed. This decreases the measurement precision of the interferometer.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an electromagnetic actuator such as a linear motor capable of suppressing the influence of heat generated from a coil in an external space.
It is another object of the present invention to provide an exposure apparatus capable of increasing the alignment speed in exposure, increasing the throughput, performing high-speed alignment, and exposing a fine pattern, a device manufacturing method using the exposure apparatus, a semiconductor manufacturing factory including the exposure apparatus, and a maintenance method for the exposure apparatus.
The present invention provides the following electromagnetic actuator. This electromagnetic actuator is an electromagnetic actuator having stationary and movable elements, comprising a magnet arranged on one of the stationary and movable elements, a coil arranged on the other one of the stationary and movable elements, a first coolant channel formed near the coil, and a second coolant channel formed in or near a surface of at least one of the stationary and movable elements. The present invention may be applied to a movable magnet type electromagnetic actuator, a movable coil type electromagnetic actuator, or another type of electromagnetic actuator.
According to a preferred aspect of the present invention, the first coolant channel is essentially formed to cool the coil, and the second coolant channel is essentially formed to adjust a surface temperature of the electromagnetic actuator.
According to another preferred aspect of the present invention, the electromagnetic actuator preferably further comprises a support which internally supports the coil, the first coolant channel is preferably formed inside the support, and the second coolant channel is preferably formed between the first coolant channel and a surface of the support or in the surface of the support. This electromagnetic actuator is suitable for an electromagnetic actuator in which the stationary element has the coil and the movable element has the magnet.
According to still another aspect of the present invention, the electromagnetic actuator may further comprise a support which supports the magnet, the support may be arranged outside the coil and the first coolant channel so as not to contact the coil and the first coolant channel, and the second coolant channel may be formed between the first coolant channel and a surface of the support or in the surface of the support. This electromagnetic actuator is also suited to an electromagnetic actuator in which the stationary element has the coil and the movable element has the magnet. The first coolant channel is preferably so formed as to surround the coil.
According to still another aspect of the present invention, the electromagnetic actuator preferably further comprises a temperature detector for detecting at least one of a temperature of a coolant flowing through the first coolant channel and a temperature of a coolant flowing through the second coolant channel, a thermo-regulator for adjusting temperatures of coolants supplied to the first and second coolant channels, and a temperature controller for controlling the thermo-
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Jones Judson H.
Mullins Burton S.
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