Driving apparatus and exposure apparatus

A driving apparatus which drives an object. The apparatus includes an electromagnetic actuator having a movable element and a stator, a surrounding member surrounding a heat portion of the electromagnetic actuator, a beam which provides the object with a driving force in accordance with movement of the movable element, a connecting member connecting the movable element and the beam, wherein the surrounding member has an opening allowing the movement of the movable element, the opening being arranged at a portion of the surrounding member not facing the object, and a heat recovery unit arranged at a position facing the opening.

FIELD OF THE INVENTION

The present invention relates to a driving apparatus which drives an object and an exposure apparatus which has a built-in driving apparatus.

BACKGROUND OF THE INVENTION

FIGS. 6 and 7are views showing the schematic structure of a stage device built into an exposure apparatus.FIG. 7shows an A-A section ofFIG. 6. A substrate101on which a pattern is to be transferred or drawn is held on a substrate chuck (not shown) mounted on a stage102. The stage102is arranged on a stage transport table103through stage guides106and driven in the Y direction. The stage guides106can include mechanical guide mechanisms or static pressure guides. The stage transport table103is supported on a stage unit table105by three or more support mechanisms104so that the influence of deformation of the stage unit table105will not be transmitted to the stage transport table103.

An example of an electromagnetic actuator which drives the stage102includes various types, e.g., a type having an iron core at the center of a coil which generates a magnetic field, a Lorentz linear motor, which uses a core-less coil, and the like. In the example shown inFIGS. 6 and 7, a square annular linear motor, which is a Lorentz type linear motor and has a high motor efficiency, is employed.

The electromagnetic actuator is constituted by a stator obtained by winding a coil108around a stator support107, and a movable element which includes magnets109. When a current is supplied to the coil108of the stator with an appropriate phase, the Lorentz force acts on the magnets109to generate a thrust in the movable element. The movable element is connected to the stage102through a beam110and moves together with the stage102. The stator has at least one coolant channel111. Joule heat generated by the coil108is recovered by a coolant flowing in the coolant channel111.

A stator outer box112is arranged outside the stator to prevent the heat generated by the coil108from adversely affecting the peripheral environment. The stator can be supported at its two ends by, e.g., support mechanisms114. When the stator is to be used as a passive counter mass which moves while canceling a reaction force generated during stage driving, the support mechanisms114support the stator such that when the stage102moves, the stator can move in the opposite direction.

As shown inFIGS. 6 and 7, in order to allow the movable element to move in the Y direction together with the stage102, the stator outer box112has a slit (opening)113which serves as a path of the beam110which connects the movable element and stage102. The slit113has a length corresponding to the drive stroke of the stage102.

As described above, the stator outer box112is provided to prevent the heat generated by the coil108from being transferred to the peripheral environment. If, however, the slit113is arranged at that portion of the constituent portion of the stator outer box112which faces the stage102, the heat generated by the coil108adversely affects the temperature distribution in the space (stage space), where the stage102is arranged, through the slit113.

Usually, the light path of a laser interferometer to measure the position of the stage102is arranged in the stage space. Temperature fluctuation in the optical path of the laser interferometer decreases the position measurement accuracy of the stage102to decrease the positioning accuracy of the stage102, and the like, thus decreasing the stability of the stage102. Although a structure on the stage102serving as the measurement target of the laser interferometer has a small thermal expansion coefficient, it can deform on the order of nanometers due to a small temperature change. This can also decrease the positioning accuracy of the stage102, thus decreasing the position reproducibility and overlapping accuracy of a pattern to be formed on the substrate101.

To prevent heat transfer to the stage space, gas around the coil108as the heat portion of the linear motor may be exhausted forcedly. However, the exhaust flow is disordered by the movement of the movable element, and the heat generated by the coil108cannot be completely prevented from flowing into the stage space. With this structure, the flow rate necessary for exhaust is very large. This poses a large load to the environment maintaining unit of the exposure apparatus and can lead to an increase in apparatus cost.

In an exposure apparatus, e.g., an EUV (Extreme Ultra Violet) exposure apparatus, which performs exposure in a vacuum or a reduced pressure environment, even if the exposure apparatus is free from the influence of a heat transfer fluid, the influence of radiant heat transfer from the stator coil to the stage space becomes an issue.

SUMMARY OF THE INVENTION

The present invention has been made based on the recognition of the above problems, and has as its object to suppress heat transfer from, e.g., an electromagnetic actuator, to an object which is driven by the electromagnetic actuator.

A driving apparatus according to the present invention is formed as a driving apparatus that drives an object. The driving apparatus comprises an electromagnetic actuator having a movable element and a stator, a surrounding member surrounding a heat portion of the electromagnetic actuator, a beam which provides the object with a driving force in accordance with movement of the movable element, and a connecting member connecting the movable element and the beam. The surrounding member has an opening allowing the movement of the movable element. The opening is arranged at a portion of the surrounding member not facing the object.

According to a preferred embodiment of the present invention, for example, the opening can be arranged at a portion of the surrounding member, which is an opposite side of the object side. Alternatively, the opening may be arranged at least in one of lower and upper portions of the surrounding member.

According to another preferred embodiment of the present invention, the driving apparatus preferably further comprises a heat recovery unit at a position facing the opening.

According to still another preferred embodiment of the present invention, the movable element can be arranged to surround the stator, and the surrounding member can be arranged to surround the stator.

According to still another preferred embodiment of the present invention, a position where the electromagnetic actuator applies a thrust to the connecting member and a barycentral position of the object substantially coincide with each other.

According to still another preferred embodiment of the present invention, the object can include a stage.

An exposure apparatus according to the present invention is formed as an exposure apparatus that transfers or draws a pattern onto a substrate, and comprises the driving apparatus described above as an apparatus which drives the substrate.

An exposure apparatus according to another aspect of the present invention is an exposure apparatus which transfers a pattern of an original onto a substrate, which comprises the driving apparatus described above as an apparatus which drives the substrate or original.

A device manufacturing method according to the present invention includes a step of exposing a substrate coated with a photosensitive agent by using the exposure apparatus described above, and a step of developing the substrate.

According to the present invention, for example, heat transfer from an electromagnetic actuator to an object driven by the electromagnetic actuator can be suppressed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1A and 1Bare views showing the schematic structure of a stage device (driving apparatus) according to the first embodiment of the present invention, which can be built into an exposure apparatus.FIG. 1Bshows the A-A section ofFIG. 1A. In the example shown inFIGS. 1A and 1B, the stage device is formed as a substrate stage device which positions a substrate. If a stage2and a structure that supports it are formed such that a pattern formed on an original (reticle) supported by the stage2is projected onto an exposure target substrate such as a wafer, the stage device can also be applied to an original stage device.

A substrate1on which a pattern is to be transferred or drawn is held on a substrate chuck (not shown) mounted on a stage (an example of an object driven by an electromagnetic actuator)2. The stage2is arranged on a stage transport table3through stage guides6and driven in a predetermined direction (Y direction). The stage guides6can include mechanical guide mechanisms or static pressure guides. The stage transport table3is supported on a stage unit table5by three or more support mechanisms4, so the influence of deformation of the stage unit table5will not be transmitted to the stage transport table3.

An example of the electromagnetic actuator which drives the stage2includes various types, e.g., a type having an iron core at the center of a coil which generates a magnetic field, a Lorentz linear motor which uses a core-less coil, and the like. In the example shown inFIGS. 1A and 1B, a square annular linear motor, which is a Lorentz type linear motor and has a high motor efficiency, is employed.

The actuator includes a stator obtained by winding a coil8around a stator support7, and a movable element which includes magnets9. When a current is supplied to the coil8of the stator with an appropriate phase, the Lorentz force acts on the magnets9to generate a thrust in the movable element. The movable element is connected to the stage2through a beam10and moves together with the stage2. Alternatively, the stage2may be formed such that it can move in the Y direction as the beam10moves and can slide in the X direction with respect to the beam10. The stage2may be driven in the X direction by an X direction driving electromagnetic actuator (typically, a linear motor). In this case, the stage2serves as an X-Y stage, which is driven in the X-Y direction.

The stator has at least one coolant channel11. Joule heat generated by the coil8serving as a heat portion is recovered by a coolant flowing in the coolant channel11. A stator outer box (surrounding member)12is arranged outside the stator to surround it, and prevents the heat generated by the coil8from adversely affecting the peripheral environment (including the stage space). A temperature adjusting channel may be formed in the upper or lower surface of the stator outer box12or in the stator outer box12and a coolant may be supplied to the channel to temperature adjust the stator outer box12. Alternatively, the upper or lower surface of the stator outer box12may be coated with a material having a low heat conductivity to suppress heat transfer from the coil8to the peripheral environment (including the stage space). The stator outer box12can be supported at its two ends by, e.g., support mechanisms19.

A support17which supports the magnets9of the movable element is connected to the beam10by connecting members18and14. The movable element transmits a driving force to the stage2in the Y direction through the beam10. The connecting member18is connected to the connecting member14through a slit (opening)13in the stator outer box (surrounding member)12, and can move as the movable element moves. The slit13in the stator outer box12is arranged at a portion that does not face the stage space (space where the stage2is arranged), in this case, at a portion which is opposite to the stage space. Thus, heat generated by the coil8is prevented from being transferred to the stage space through the slit13.

With this structure, the position where the electromagnetic actuator supplies a thrust to the connecting member18can be easily set to substantially coincide with the barycentral position of a moving portion including the stage2. This prevents a rotational component from being generated when the stage2is driven. The connecting member14can be formed to surround, e.g., the stator outer box12.

A heat recovery unit15is preferably arranged at a portion that faces the slit13of the stator outer box12. Then, the influence of heat radiated from the coil8through the slit13and transferred to the peripheral environment can be decreased.

When the stage device is used in a vacuum atmosphere, as the heat portion of the electromagnetic actuator is completely concealed from the stage space, the influence of direct radiant heat transfer can be shielded completely.

FIG. 2is a view showing the schematic structure of a stage device (driving apparatus) according to the second embodiment of the present invention, which can be built into an exposure apparatus. The same constituent elements as those inFIGS. 1A and 1Bare denoted by the same reference numerals. Matters that are not particularly referred to can follow the first embodiment.

In the embodiment shown inFIG. 2, a slit (opening)13is formed in the lower portion of a stator outer box (surrounding member)12. A support17which supports magnets9is connected to a beam10through a connecting member20connected under the support17. In place of this structure, the slit13may be formed in the upper portion of the stator outer box12. In the second embodiment as well, the slit13is arranged at that portion of the stator outer box12which does not face the stage space. In the structure in which the slit13is formed in the lower or upper portion of the stator outer box12, the connecting member that connects the support17of the movable element and the beam10can be made smaller than in the structure shown inFIGS. 1A and 1B. Thus, the mass of the entire moving portion including the movable element, beam10, stage2, and the like, can be decreased.

A heat recovery unit15is preferably arranged at a portion that faces the slit13of the stator outer box12. Then, the influence of heat radiated from a coil8and transferred to the peripheral environment through the slit13can be decreased.

FIG. 3is a view showing the schematic structure of a stage device (driving apparatus) according to the third embodiment of the present invention, which can be built into an exposure apparatus. The same constituent elements as those inFIGS. 1A,1B, and2are denoted by the same reference numerals. Matters that are not particularly referred to can follow the first and second embodiments.

In the embodiment shown inFIG. 3, slits (openings)13are formed in the lower and upper portions, respectively, of a stator outer box (surrounding member)12. A support17which supports magnets9is connected to a beam10through connecting members21connected under the support17and to the upper portion of the support17. In this structure as well, the slits13are arranged at those portions of the stator outer box12which do not face the stage space. According to this embodiment, the rigidity of the moving portion, particularly of portions that connect the support17and beam10, can be increased to be higher than that in the second embodiment. The support17and beam10may be connected to each other at three or more portions.

Heat recovery units15are preferably arranged at portions that face the slits13of the stator outer box12. Then, the influence of heat radiated from a coil8and transferred to the peripheral environment through the slits13can be decreased.

FIG. 4is a view showing the schematic structure of a stage device (driving apparatus) according to the fourth embodiment of the present invention which can be built into an exposure apparatus. The same constituent elements as those inFIGS. 1A,1B,2, and3are denoted by the same reference numerals. Matters that are not particularly referred to can follow the first, second, and third embodiments.

In the fourth embodiment, as an electromagnetic actuator, a Lorentz back yoke type linear motor in which coils9are arranged in a planar manner is employed. In this structure, a slit (opening)13is formed in a stator outer box (surrounding member)12which surrounds and supports a coil8serving as a heat portion. The slit13is arranged at a portion that does not face the stage space, in this case, at a portion opposite to the stage space.

A heat recovery unit15is preferably arranged at a portion that faces the slit13of the stator outer box12. Then, the influence of heat radiated from the coil8and transferred to the peripheral environment through the slit13can be decreased.

Although the stator and stator outer box are substantially square in each of the first to fourth embodiments, they can be changed to have other polygonal shapes, or circular or elliptical shapes. Note that the structure that has the best area efficiency when mounted on a stage device is a square.

FIG. 5is a view showing the schematic structure of a stage device (driving apparatus) according to the fifth embodiment of the present invention, which can be built into an exposure apparatus. The same constituent elements as those inFIGS. 1A,1B,2,3, and4are denoted by the same reference numerals. Matters that are not particularly referred to can follow the first, second, third, and fourth embodiments.

In the fifth embodiment, as an electromagnetic actuator, a cylindrical linear motor having a motor efficiency which is equivalent to that of a prismatic linear motor is employed. In this structure as well, a slit (opening)13of a stator outer box (surrounding member)12is arranged at a portion that does not face the stage space, in this case, a portion opposite to the stage space.

A heat recovery unit15is preferably arranged at a portion that faces the slit13of the stator outer box12. Then, the influence of heat radiated from the coil8and transferred to the peripheral environment through the slit13can be decreased.

FIG. 8is a view showing the schematic arrangement of an exposure apparatus into which a stage device (driving apparatus) typically described as the embodiments shown inFIGS. 1A,1B, and2to5is built as a substrate stage device. Typically, a substrate stage device100includes, in addition to an electromagnetic actuator which drives a stage2in the Y direction as described above, an electromagnetic actuator which drives the stage2in the X direction. Typically, in the substrate stage device, the stage2is driven by a fine movement stage device which can be controlled in six axes. The fine movement stage device is driven by an X-Y direction driving electromagnetic actuator as described above.

An original R held by an original stage device120is illuminated by an illumination optical system130. The pattern of the original R is projected and transferred onto a substrate1on the stage2through an optical system110. For example, the exposure apparatus can be formed as a stepper, scanner, or another apparatus. The exposure apparatus can be formed to draw a pattern on the substrate1with a charged particle beam such as an electron beam.

The stage device typically described as the embodiments shown inFIGS. 1A and 1B, and2to5can also be formed as an original stage device120which moves an original R. In this case, a stage2and a structure that supports it can be formed such that a pattern formed on the original R is projected onto a wafer substrate.

As a device manufacturing process, which uses this exposure apparatus, a semiconductor device manufacturing process will be exemplified.FIG. 9is a flowchart showing the flow of the entire semiconductor device manufacturing process. In step1(circuit design), the circuit of a semiconductor device is designed. In step2(mask fabrication), a mask is fabricated on the basis of the designed circuit pattern.

In step3(wafer manufacture), a wafer is manufactured using a material such as silicon. In step4(wafer process), called a preprocess, an actual circuit is formed on the wafer by the exposure apparatus described above in accordance with lithography using the mask and wafer described above. In the next step5(assembly), called a post-process, a semiconductor chip is formed from the wafer fabricated in step4. This step includes processes such as assembly (dicing and bonding) and packaging (chip encapsulation). In step6(inspection), inspections, such as an operation check test and a durability test of the semiconductor device fabricated in step5, are performed. A semiconductor device is finished with these steps and shipped in step7.

The wafer process of step4has the following steps (FIG. 10), i.e., an oxidation step of oxidizing the surface of the wafer, a CVD step of forming an insulating film on the wafer surface, an electrode formation step of forming an electrode on the wafer by deposition, an ion implantation step of implanting ions in the wafer, a resist process step of applying a photosensitive agent to the wafer, an exposure step of transferring the circuit pattern to the wafer after the resist process step by the exposure apparatus described above, a developing step of developing the wafer exposed in the exposure step, an etching step of removing portions other than the resist image developed in the developing step, and a resist removal step of removing any unnecessary resist after etching. These steps are repeated to form multiple circuit patterns on the wafer.

CLAIM OF PRIORITY

This application claims priority from Japanese Patent Application No. 2004 073403 filed on Mar. 15, 2004, the entire contents of which are hereby incorporated by reference herein.