Photocopying – Projection printing and copying cameras – Detailed holder for photosensitive paper
Reexamination Certificate
2003-04-07
2004-05-25
Kim, Peter B. (Department: 2851)
Photocopying
Projection printing and copying cameras
Detailed holder for photosensitive paper
C355S053000, C355S075000, C310S012060, C318S649000
Reexamination Certificate
active
06741332
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to stage systems, exposure apparatus, and device manufacturing methods, and more particularly to a stage system comprising a stage main body that moves along a movement plane of a supporting member, a mover that is connected to the stage main body, and a stator that is provided independent of the supporting member of vibration, an exposure apparatus that comprises the stage system as a drive system for at least one of a mask and a substrate, and a device manufacturing method that uses the exposure apparatus when exposure is performed.
2. Description of the Related Art
In a conventional photolithographic process for manufacturing devices such as semiconductors and liquid crystal display devices, projection exposure apparatus of a sequential moving type such as a reduction projection exposure apparatus based on a step-and-repeat method (a so-called stepper) that reduces and transfers a pattern formed on a mask or a reticle (hereinafter generally referred to as a “reticle”) onto a substrate such as a wafer or a glass plate (hereinafter generally referred to as a “wafer”) coated with a resist or the like via a projection optical system, and a scanning projection exposure apparatus based on a step-and-scan method (a so-called scanning stepper), which is an improvement of the stepper, are being widely used.
For example, in a scanning stepper, a reticle stage supporting member is a movement reference of a reticle stage on which a reticle is held. And, since it plays an important part when setting an imaging plane on which an image of a pattern formed on the reticle is formed by a projection optical system, vibration of the reticle supporting member is preferably suppressed as much as possible, even when the reticle stage is being driven.
In addition, with a wafer stage of a projection exposure apparatus, in most cases a wafer table that can be driven at least in a Z tilt is arranged on an XY stage that can be driven in an XY plane in order to make the wafer surface coincide with the image plane on which the image of the pattern on the reticle is formed, and the wafer is held on the wafer table. In such cases, when vibration occurs in a wafer stage supporting member that exceeds a predetermined amount, the vibration cannot be attenuated sufficiently, which causes the control accuracy of the position of the wafer table in the Z-axis direction to decrease.
Therefore, when the reticle stage or the wafer stage is driven, such as by a linear motor, in order to keep a reaction force that occurs when the stage is driven by the linear motor from traveling to the stage supporting member, the stator of the linear motor on which the reaction force due to the drive of the stage acts is to be separated from the stage supporting member, or a so-called counter mass mechanism where the stator moves for conservation of momentum by the action of the reaction force is to be employed. With the above arrangement, the stage supporting member is isolated from vibration caused by the reaction force that occurs when the stage is driven.
In addition, in order to prevent the stage supporting member from vibrating due to vibration from the floor, dampers are preferably arranged in between the stage supporting member and the floor so as to isolate vibration with respect to the stage supporting member.
In both the reticle stage and the wafer stage, a linear motor is used in many cases as a means for driving in at least a long stroke direction (normally a direction along one axis within a horizontal plane). With such a linear motor, permissible relative displacement in between the mover and the stator in a direction perpendicular to the horizontal surface (a height direction) is small, such as around the range of ±0.5 mm, which is the limit for obtaining effective thrust.
Meanwhile, as the damper referred to above, in order to obtain a sufficient vibration attenuation effect, an AVIS (a vibration isolator the performs vibration attenuation by a combination of a mechanical damper that can bear heavy weight such as an air damper and an electromagnetic actuator such as a voice coil motor) is frequently employed. That is, the AVIS proactively drives the stage supporting member, so as to prevent the vibration in the stage bed caused by the vibration from the floor. With the AVIS, however, the permissible movable stroke from a neutral position to a position where a stopper (mechanical stopper) that mechanically limits its drive is arranged is around ±3 mm. Therefore, when the AVIS goes out of control, since the drive strokes of the stage supporting member by the AVIS exceeds the above permissible range of the linear motor the linear motor may consequently be damaged due to the stator and the mover of the linear motor coming into contact with each other.
As a method of preventing such a situation, for example, guide portions of the stator and the mover of the linear motor may each be arranged separately from a guide surface on the stage supporting member. With such an arrangement, however, since the guide surface of each of the stages is originally arranged on the stage supporting member, it becomes difficult to maintain a suitable positional relationship between the guide surfaces of the stages and the guide portions of the stator and mover of the linear motor. And, as a consequence, the guide portions of the stator and the mover of the linear motor could be damaged.
Therefore, in the conventional art, maintenance had to be frequently preformed on the linear motor or on its guide portion. This, however, leads to an increase in the downtime of the exposure apparatus, which in turn, becomes a cause of decreasing the productivity of a device as an end product.
SUMMARY OF THE INVENTION
The present invention was made under such circumstances, and has as its first object to provide a stage system that can stably drive a stage main body for a long period of time.
In addition, the second object of the present invention is to provide an exposure apparatus that can improve operation efficiency.
Moreover, the third object of the present invention is to provide a device manufacturing method that can improve productivity of a device.
According to the first aspect of the present invention, there is provided a stage system comprising: a stage main body that is movable along a movement plane of a supporting member; a mover that is coupled with the stage main body; a stator that cooperates with the mover to move the stage main body, the stator being provided independent of the supporting member regarding vibration; a driver that drives the supporting member; and a releaser that releases a coupling between the stage main body and the mover when a drive amount of the supporting member by the driver exceeds a predetermined amount.
With the stage system, the stage main body is driven along the movement plane of the supporting member, with the stator provided independent of the supporting member regarding vibration cooperating with the mover coupled with the stage main body. The driver drives the supporting member, however, when the drive amount of the driver exceeds a predetermined value, the coupling between the stage main body and the mover is released. That is, when the drive amount of the supporting member exceeds a predetermined value, the releaser releases the coupling between the stage main body and the mover before the mover coupled with the stage main body comes into contact with the stator and both parts are put under a large stress. As a consequence, the mover and stator can be kept from being damaged from the contact. In addition, since the stator is provided independent of the supporting member regarding vibration, the reaction force generated in the stator when the stage main body is driven does not make the supporting member vibrate, therefore, position control of the stage main body moving along the movement plane of the supporting member can be performed with high precision. Accordingly, with the stage system, the stage main bo
Kim Peter B.
Nikon Corporation
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