JP2002343850A - Stage apparatus and exposure system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a positional deviation of a substrate held at a moving unit in the case of moving the moving unit. SOLUTION: A stage apparatus comprises the moving unit H which holds the substrate R on a holding surface and moves the substrate. The apparatus further comprises energizing units 16, 17 for imparting forces to the substrate R along its holding surfaces, and a controller for controlling the units 16, 17 based on an inertial force of the substrate R in association with the movement of the substrate H.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a mask, a wafer,
The present invention relates to a stage device on which a moving body that holds a substrate such as a glass substrate moves, and an exposure device that performs an exposure process using a mask and a photosensitive substrate held by the stage device, and particularly to devices such as semiconductor integrated circuits and liquid crystal displays. The present invention relates to a stage apparatus and an exposure apparatus suitable for use in a lithography step when manufacturing the device.

[0002]

2. Description of the Related Art Conventionally, various exposure apparatuses have been used for manufacturing a semiconductor element or a liquid crystal display element by a photolithography process. At present, however, a photomask or a reticle (hereinafter referred to as a “reticle”) is used. Projection exposure apparatuses that transfer a pattern image (collectively referred to as “pattern image”) onto a substrate such as a wafer or a glass plate having a surface coated with a photosensitive agent such as a photoresist via a projection optical system are generally used. In recent years, as a projection exposure apparatus, a substrate is placed on a two-dimensionally movable substrate stage, and the substrate is stepped by the substrate stage, and a reticle pattern image is shot on each of the shots on the substrate. A so-called step-and-repeat type reduction projection exposure apparatus (so-called stepper) that repeats an operation of sequentially exposing regions is mainly used.

Recently, a step-and-scan type projection exposure apparatus (for example, a scanning exposure apparatus as disclosed in Japanese Patent Application Laid-Open No. Hei. Devices) have also become relatively popular. This step-and-scan type projection exposure apparatus (scanning stepper) can expose a large field with a smaller optical system as compared with a stepper, so that the projection optical system can be easily manufactured and a large-field exposure apparatus can be used. Thus, high throughput can be expected due to the decrease in the number of shots due to the above, and averaging effects can be expected by relatively scanning the reticle and the wafer with respect to the projection optical system, and an improvement in distortion and depth of focus can be expected. Furthermore, as the degree of integration of semiconductor elements increases from 16M (mega) to 64M DRAM, and in the future, 256M, 1G (giga), etc., with the era, a large field becomes indispensable.
It is said that a scanning projection exposure apparatus will become mainstream in place of a stepper.

In these exposure apparatuses, for example, semiconductor exposure apparatuses used for manufacturing semiconductor devices, a reticle and a wafer are two-dimensionally moved while being held by holders in a stage device. FIG. 10 schematically shows an example of a reticle stage in a conventional stage device.

The reticle stage shown in FIG. 1 includes a reticle holder H for holding a reticle (substrate) R as a mask, and a reticle holding surface S is provided with a suction path K between the reticle R and the reticle R. By performing negative pressure suction (vacuum suction) by the negative pressure suction device V connected to the suction path K,
The reticle R is adsorbed to the holding surface S of the holder H, and the reticle R is held by a static friction force with the suction force as a vertical force. The reticle R is configured to obtain a thrust through a reticle holder H driven at the time of the above-described step movement or scanning movement, by a static friction force having a suction force on the holding surface S as a vertical drag component. .

[0006]

However, the conventional stage apparatus and exposure apparatus as described above have the following problems. In a reticle stage of a step-and-scan type exposure apparatus, first, a reticle reference is aligned (aligned) on the order of nm in a stationary state, and then a distance between the reticle holder and a movable mirror attached to the reticle holder H is measured. Since the dynamic positioning and control of the reticle R is performed using the measurement results of the interferometer, the relative positional relationship between the reticle R and the reticle holder H on which the movable mirror is installed can be changed even when the stage moves with acceleration and deceleration.
It must be kept in the order of m. In recent years, in order to improve the throughput and the productivity, the acceleration at the time of moving the stage tends to increase in recent years.

As shown in FIG. 11, a thrust Fd for accelerating and decelerating the reticle holder H and the reticle R is applied to the reticle holder H by a drive device (not shown) such as a motor. As described above, the reticle R obtains a thrust through the reticle holder H by the static friction force Fm having the suction force on the holding surface S as a vertical drag component, but the reticle R has a thrust direction necessary for acceleration and deceleration. Since the inertial force Fi acts on the opposite side, a shear force Fs corresponding to the inertial force Fi is generated on the holding surface S. This shear force Fs is the static friction force Fm
Is exceeded, a relative displacement occurs between the reticle R and the reticle holder H.

On the other hand, since the reticle R is a standard product and cannot be reduced in weight, conventionally, a method of increasing the vertical drag by increasing the suction area to increase the acceleration in the reticle stage has been adopted. Was. However, the reticle R needs to transmit exposure light,
As shown in FIG. 12, since the holding surface S must be arranged so as to avoid the pattern area PA, there is a limit in a method of increasing the suction area for the reticle R under the current situation where the occupancy of the pattern area PA is high. Therefore, there is a limit to the normal force due to the attraction force, and it is difficult to further increase the acceleration in the reticle holding that depends only on the static friction force proportional to the normal force. In addition, the static friction coefficient at a level at which the relative positional relationship between the reticle R and the holder H does not change even when a shearing force equal to or less than the static friction force is applied to the holding surface S is usually used in a measurement in which nm order is a problem. It has been found to be small relative to the coefficient of static friction measured on the order of mm, μm, which can be considered.

In order to prevent relative displacement in such a high acceleration state, generally, as shown in FIG. 13, a method of clamping the reticle R with clamping members C and C from both sides in the traveling direction is considered. Have been. However, in this case, as shown in FIG. 14, when clamping is performed from the front and rear, the clamping force is eventually balanced, and is equivalent to a state in which the spring B having the rigidity of the clamp member C is supported at the balanced position from both sides. become. In such a system represented by the spring B, a condition for generating a force for preventing a relative displacement is represented by F = kx (k is a spring constant, x is a displacement). If not allowed, the spring constant k (that is, the rigidity of the clamp portion) necessary for preventing the relative displacement is enormous, and is not realized in practice. The same applies to the case where clamping is performed from both left and right sides in the traveling direction.

Further, there is a method of increasing the vertical reaction force by pressing the reticle R from above the holding surface S to increase the static friction force. However, a force from above the reticle R and a mechanism for generating the force are also available. As long as the fulcrum reaction force does not work coaxially, even if the reticle holder H is made of ceramics
Is formed, when a force required to obtain a required static friction force at a high acceleration is applied to the reticle R, the holder H is bent on the order of several hundred nm, and the reticle R adsorbed to the holder H is bent. Also, by bending according to this, it appears as an aberration at the time of exposure. It is very difficult to design a structure that satisfies the coaxial condition and presses the reticle R because of the existence of the suction unit piping and the like and the space.

Further, the flatness of the area around the reticle R on the holder H is not always guaranteed, so it is unclear where the reticle R comes into contact with the reticle R when pressed from above. It is difficult to satisfy the above coaxial condition, and there is a high risk that the reticle R will appear as distortion. Further, even if a design satisfying such coaxial conditions can be achieved, since the static friction force between the reticle R and the holder H is small, it is necessary to apply a large force to obtain a sufficient vertical drag. It also causes the reticle to be distorted.

As described above, when the relative positional deviation between the reticle R and the holder H occurs, problems such as a remarkable decrease in alignment accuracy of the reticle occur. Further, even if the reticle R is distorted, the transfer accuracy of the pattern is reduced due to aberration or the like, and a problem occurs that the predetermined exposure accuracy cannot be satisfied.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and provides a stage device capable of preventing a displacement of a substrate held by a moving body when the moving body moves. It is another object of the present invention to provide an exposure apparatus capable of increasing a moving speed and improving a throughput by including the stage device.

[0014]

In order to achieve the above object, the present invention employs the following structure corresponding to FIGS. 1 to 8 showing an embodiment. The stage device according to the present invention is a stage device (4) including a moving body (H) that moves while holding the substrate (R) on a holding surface (S), and the substrate (R) moves along the holding surface (S). A biasing device (16, 17) for applying a force to the moving body (H) and a control device (16, 17) for controlling the biasing devices (16, 17) based on the inertial force of the substrate (R) accompanying the movement of the moving body (H) 18).

Therefore, in the stage device of the present invention, when an inertial force is applied to the substrate (R) as the moving body (H) moves, a force is applied in a direction opposite to the direction in which the inertial force acts. Thus, the inertial force can be offset or reduced. At this time, by controlling the magnitude of the applied force,
The shearing force acting on the holding surface (S) can be suppressed to a value equal to or less than the static frictional force. Even when a high acceleration that cannot be held by only the static frictional force due to the attraction force is applied,
The relative positional relationship between the substrate (R) and the moving body (H) can be maintained in a stationary state.

Further, the exposure apparatus of the present invention exposes a pattern of a mask (R) held on a mask stage (2) to a photosensitive substrate (W) held on a substrate stage (5). Wherein the stage device (4) according to any one of claims 1 to 5 is used as at least one of the mask stage (2) and the substrate stage (5).

Therefore, in the exposure apparatus of the present invention, the substrate such as the mask (R) or the wafer (W) is more securely fixed and held on the stage without causing a positional shift. It is possible to improve the throughput of the exposure apparatus by increasing the moving speed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a stage apparatus and an exposure apparatus according to the present invention will be described below with reference to FIGS. Here, an example in which a scanning stepper that transfers a circuit pattern of a semiconductor device formed on a reticle onto a wafer while synchronously moving a reticle and a wafer is used as an exposure apparatus will be described. In this exposure apparatus, the stage device of the present invention is applied to a reticle stage. In these figures, the same components as those in FIGS. 10 to 14 shown as conventional examples are denoted by the same reference numerals,
The description is omitted.

An exposure apparatus 1 shown in FIG. 1 includes a light source (not shown).
An illumination optical system IU for illuminating a rectangular (or circular) illumination area on a reticle (substrate) R as a mask with uniform illumination by exposure illumination light from the reticle, and a reticle stage for holding and moving the reticle R (Mask Stage) 2 and a stage device 4 including a reticle surface plate 3 supporting the reticle stage 2, and a projection optical system PL for projecting illumination light emitted from the reticle R onto a wafer (photosensitive substrate) W
And a stage device 7 including a wafer stage (substrate stage) 5 for holding and moving the wafer W and a wafer surface plate 6 for holding the wafer stage 5;
And a reaction frame 8 that supports the projection optical system PL. Here, the direction of the optical axis of the projection optical system PL is defined as the Z direction, the direction of the synchronous movement of the reticle R and the wafer W is defined as the Y direction, and the direction of the asynchronous movement is defined as the X direction. The rotation directions around the respective axes are denoted by θZ, θY, and θX.

The illumination optical system IU is supported by a support column 9 fixed on the upper surface of the reaction frame 8. Examples of the illumination light for exposure include far ultraviolet light (DUV light) such as an ultraviolet bright line (g-line, i-line) and KrF excimer laser light (wavelength: 248 nm) emitted from an ultra-high pressure mercury lamp, and ArF. Excimer laser light (wavelength 19
Vacuum ultraviolet light (VUV) such as 3 nm) and F ₂ laser light (wavelength 157 nm).

The reaction frame 8 is mounted on a base plate 10 placed horizontally on the floor, and has inwardly projecting steps 8a and 8b formed on the upper and lower sides thereof. ing.

In the stage device 4, the reticle platen 3 is
Step 8a of reaction frame 8 at each corner
An opening 3a through which a pattern image formed on the reticle R passes is supported in a substantially horizontal manner via an anti-vibration unit 11 (note that the anti-vibration unit on the back side of the drawing is not shown). Are formed. Note that metal or ceramics can be used as the material of the reticle surface plate 3. The anti-vibration unit 11 has a configuration in which an air mount 12 whose internal pressure can be adjusted and a voice coil motor 13 are arranged in series on the step 8a. With these vibration isolation units 11, micro vibrations transmitted to the reticle surface plate 3 via the base plate 10 and the reaction frame 8 are insulated at a micro G level (G
Is the gravitational acceleration).

The reticle stage 2 includes a reticle holder (moving body) H that is supported movably two-dimensionally along the reticle surface plate 3. A plurality of air bearings (air pads) 14 are fixed to the bottom surface of the reticle holder H, and the reticle holder H is levitated and supported on the reticle surface plate 3 by a clearance of about several microns by these air bearings 14. I have. At the center of the reticle holder H, there is formed an opening 2a which communicates with the opening 3a of the reticle platen 3 and through which the pattern image of the reticle R passes.

The reticle holder H will be described in detail. As shown in FIG. 2, the reticle holder 2 has a pair of air guides 51 provided on the lower surface side edge and fixed to the upper surface of the reticle platen 3 and extending in the Y-axis direction. Are guided in the Y-axis direction by moving along the Y guides 52, 52. Each of the air guides 51 is supported by the Y guides 52 and 52 by an air bearing (not shown) in a non-contact manner. A mover 21 protrudes from the + X side edge of the reticle holder H, and a stator 20 extending in the Y-axis direction is opposed to the mover 21 on the reticle surface plate 3 via a support member 19. Supported. And
A moving coil type linear motor 15 is configured by the mover 21 and the stator 20, and the reticle holder H is moved in the Y direction by driving the mover 21 by electromagnetic interaction with the stator 20. Go to
Note that the stator 20 may be provided on the reaction frame 8 instead of on the reticle surface plate 3. When the stator 20 is provided on the reaction frame 8, the stator 20 is fixed to the reaction frame 8, and the reaction force acting on the stator 20 due to the movement of the reticle holder H is released to the floor via the reaction frame 8. Is also good.

Although not shown, a pair of Y movable mirrors each composed of a corner cube are fixed at an end in the -Y direction of the reticle holder H at intervals in the X direction. An X movable mirror composed of a plane mirror extending in the Y direction is fixed to an end of the mirror. Then, three laser interferometers (all not shown) for irradiating the movable mirrors with the measurement beam measure the distances to the respective movable mirrors, whereby the X and Y of the reticle holder H (therefore, the reticle R) are measured. , ΘZ (rotation around the Z axis) direction are measured with high accuracy. As a material of the reticle holder, a low thermal expansion ceramic made of metal, cordierite, or SiC can be used.

Cordierite ceramics are usually
Are those having the composition _{2MgO-2Al 2 O 3 -5SiO 2} , ( without the or additives) was blended metal oxide at a predetermined ratio, after molding into a predetermined shape, from 1300 to 1550
It can be manufactured by firing in an oxidizing atmosphere at a temperature of ° C.
This cordierite-based ceramic has a coefficient of thermal expansion of 0.1 × 10 ⁻⁶ / ° C. without additives, and has a cordierite having a Y (yttrium) or rare earth element (for example, Er, Yb, Sm, By adding at least one of Lu and Ce) at a ratio of 3 to 15% by weight in terms of oxide, a coefficient of thermal expansion of 1.0 × 10 ⁻⁶ / ° C. or less and a high Young's modulus are exhibited. Become something.

On the upper surface of the reticle holder H, a holding unit 22 extending in the Y direction and holding the reticle R by suction is provided.
They are provided at predetermined intervals in the direction. As shown in FIG. 3, the holding portion 22 has a holding surface S for holding the reticle R.
The suction passage K is formed so as to open. This suction path K
Is connected to a negative pressure suction device V, and the reticle R is sucked and held on the holding surface S by suctioning the suction path K with a negative pressure while the reticle R is placed on the holding surface S. I have.

On the other hand, as shown in FIGS. 2 and 3, on the reticle holder H, the actuator 16 (+ Y
Side) and 17 (−Y side) are arranged at intervals in the X direction and near the holding unit 22. The actuator (first urging device) 16 applies an auxiliary force (or an urging force described later) in the −Y direction to the side surface of the reticle R along the holding surface S, and is a VCM (voice coil motor). ), An EI core, a rotary motor, and the like. Similarly, the actuator (second urging device) 17 applies an auxiliary force (or an urging force described later) in the + Y direction to the side surface of the reticle R along the holding surface S. Actuator 1 sandwiching reticle R
Reference numerals 6 and 17 are arranged so as to apply the auxiliary force (or urging force) coaxially along the Y direction. The driving of these actuators 16 and 17 is independently controlled by the control device 18 (see FIG. 4).

Returning to FIG. 1, as the projection optical system PL, here, both the object plane (reticle R) side and the image plane (wafer W) side are telecentric and have a circular projection visual field. A refraction optical system having a 1/4 (or 1/5) reduction magnification composed of a refraction optical element (lens element) made of a glass material is used. For this reason, when the reticle R is irradiated with the illumination light, of the circuit pattern on the reticle R, an image forming light beam from a portion illuminated by the illumination light enters the projection optical system PL, and the circuit pattern is partially inverted. The image is limited to a slit shape and formed at the center of the circular field on the image plane side of the projection optical system PL. Thus, the projected partial inverted image of the circuit pattern is transferred to the wafer W placed on the image forming plane of the projection optical system PL.
Of the plurality of upper shot areas, the reduced transfer is performed to the resist layer on the surface of one shot area.

On the outer periphery of the lens barrel of the projection optical system PL, a flange 23 integrated with the lens barrel is provided. Then, the projection optical system PL is mounted on a lens barrel base 25 made of a casting or the like substantially horizontally supported on the step portion 8b of the reaction frame 8 via a vibration isolating unit 24 with the optical axis direction being the Z direction. And the flange 23 is engaged. The lens barrel base 25 may be made of a ceramic material having high rigidity and low thermal expansion.

The material of the flange 23 is a material having a low thermal expansion, for example, Invar (nickel 36%,
(A low-expansion alloy composed of 0.25% of manganese and iron containing trace amounts of carbon and other elements). The flange 23 constitutes a so-called kinematic support mount that supports the projection optical system PL at three points with respect to the barrel base 25 via points, surfaces, and V-grooves. When such a kinematic support structure is employed, it is easy to assemble the projection optical system PL to the lens barrel base 25, and it is caused by vibrations, temperature changes, and the like of the assembled lens barrel base 25 and the projection optical system PL. There is an advantage that stress can be reduced most effectively.

The anti-vibration unit 24 is disposed at each corner of the lens barrel base 25 (the anti-vibration unit on the back side of the drawing is not shown), and an air mount 26 whose internal pressure can be adjusted.
And the voice coil motor 27 are arranged in series on the step 8b. These vibration isolation units 24 insulate, at the micro G level, minute vibrations transmitted to the lens barrel base 25 (and the projection optical system PL) via the base plate 10 and the reaction frame 8.

The stage device 7 includes a wafer stage 5, a wafer surface plate 6 for supporting the wafer stage 5 so as to be movable in a two-dimensional direction along the XY plane, and a wafer stage 5, which is provided integrally with the wafer stage 5 and holds the wafer W by suction. Wafer holder S
T, an X guide bar XG that supports the wafer stage 5 and the wafer holder ST so as to be relatively movable. A plurality of air bearings (air pads) 28 which are non-contact bearings are provided on the bottom surface of the wafer stage 5.
The wafer stage 5 is supported by the air bearings 28 so as to float above the wafer surface plate 6 with a clearance of, for example, about several microns.

The wafer surface plate 6 is supported substantially horizontally above the base plate 10 via a vibration isolating unit 29. The anti-vibration unit 29 is disposed at each corner of the wafer surface plate 6 (the anti-vibration unit on the back side of the drawing is not shown), and the air mount 30 and the voice coil motor 31 whose internal pressure can be adjusted include the base plate 10. It has a configuration arranged in parallel on the top. These anti-vibration units 29
Thus, micro vibration transmitted to the wafer surface plate 6 via the base plate 10 is insulated at the micro G level.

As shown in FIG. 5, the X guide bar XG is
It has a long shape along the X direction, and movers 36, 36 each composed of an armature unit are provided at both ends in the length direction. The stators 37, 37 having magnet units corresponding to the movers 36, 36 are provided on support portions 32, 32 protruding from the base plate 10 (see FIG. 1, and in FIG. 1, the mover 36). And the stator 37 is shown in a simplified manner). The moving coil 36 and the stator 37 constitute moving coil linear motors 33, 33.
Is driven by electromagnetic interaction with the stator 37, the X guide bar XG moves in the Y direction, and the drive of the linear motors 33, 33 is adjusted so that θ
Rotate in the Z direction. That is, this linear motor 3
3, the wafer stage 5 (and the wafer holder ST) is substantially integrated with the X guide bar XG in the Y direction and θZ.
It is driven in the direction.

The mover of the X trim motor 34 is mounted on the -X direction side of the X guide bar XG. The X trim motor 34 adjusts the position of the X guide bar XG in the X direction by generating a thrust in the X direction, and a stator (not shown) is provided on the reaction frame 8. Therefore, the wafer stage 5 is set to X
The reaction force when driving in the direction is transmitted to the base plate 10 via the reaction frame 8.

The wafer holder ST is in non-contact with the X guide bar XG so as to be relatively movable in the X direction via a magnetic guide including a magnet and an actuator that maintains a predetermined gap in the Z direction between the wafer holder ST and the X guide bar XG. It is supported and held by. Further, the wafer holder ST is driven in the X direction by electromagnetic interaction by the X linear motor 35 embedded in the X guide bar XG. The wafer holder ST is made of the same material as the reticle holder H. A movable mirror 43 extending along the Y direction and a movable mirror 48 extending along the X direction are arranged on the side edge on the wafer holder ST, and the movable mirror 43 is measured with respect to these movable mirrors. Three laser interferometers (moving mirror 43
One for the movable mirror 48 and two for the movable mirror 48; each is not shown), and measures the distance to each movable mirror, so that the X, Y, θZ (around the Z axis) of the wafer holder ST (and thus the wafer W) The position in the (rotation) direction is measured with high accuracy.

Further, three laser interferometers 45 are fixed to three different locations on the flange 23 of the projection optical system PL (however, one of these laser interferometers is typically shown in FIG. 1). Has been). Openings 25a are respectively formed in portions of the lens barrel base 25 facing each of the laser interferometers 45, and a laser beam (length measuring beam) in the Z direction is transmitted from each of the laser interferometers 45 through these openings 25a. Is irradiated toward the wafer surface plate 6. A reflection surface is formed on the upper surface of the wafer surface plate 6 at a position facing each measurement beam. Therefore, the three laser interferometers 45 measure three different Z positions of the wafer surface plate 6 with reference to the flange 23 (however,
FIG. 1 shows a state in which the central shot area of wafer W on wafer stage 5 is directly below the optical axis of projection optical system PL, so that the length measurement beam is applied to wafer stage 5.
It is in a state of being interrupted by). Note that the wafer holder S
A reflective surface is formed on the upper surface of T, and different 3
An interferometer that measures the position of the point in the Z direction with reference to the projection optical system PL or the flange 23 may be provided.

FIG. 4 is a control block diagram of the exposure apparatus 1. As shown in this figure, the measurement results of the laser interferometer for reticle and the laser interferometer for wafer are input to the control device 18. The controller 18 also receives input of exposure data (recipe) relating to the arrangement position and exposure sequence of the shot areas, the position and speed of synchronous scanning, and the like.
Controls the driving of the linear motors 15, 33, 35, the X trim motor 34, the actuators 16, 17 and the like based on the measurement results of the interferometer and the exposure data.

Next, the operation of the stage apparatus 4 among the stage apparatus and the exposure apparatus configured as described above will be described first. Here, under the control of the control device 18,
The reticle R and the reticle holder H are moved in the −Y direction via the linear motor 15.

Before the synchronous scanning, the reticle R is held by suction on the holding surface S of the reticle holder H. At this time, FIG.
As shown in (b), both of the actuators 16 and 17 apply a weak urging force Ff to the reticle R that does not exceed the static friction force on the holding surface S and does not distort the reticle R. Thereby, the reticle holder H
When the actuators 16 and 17 separate or abut against the reticle R during acceleration and deceleration, the impact on the reticle R can be prevented, and the relative displacement caused by the impact can be prevented. it can.

Next, at the time of acceleration such as the start of synchronous scanning, a thrust Fd in the -Y direction is applied to the reticle holder H via the linear motor 15 as shown in FIG. At this time, inertial force Fi acts on reticle R in the + Y direction according to thrust Fd (and the mass of reticle R and reticle holder H). Then, the control device 18 applies the urging force Ff to the reticle R in the + Y direction by the actuator 17.
And the actuators 16 and 17 are individually controlled so as to apply in the −Y direction an assisting force Fh of a magnitude that balances the force obtained by adding the inertial force Fi and the urging force Ff by the actuator 16. Accordingly, it is possible to prevent a shearing force exceeding the static frictional force Fm on the holding surface S from being applied to the reticle R with the acceleration of the reticle holder H.

The auxiliary force Fh applied to the reticle R by the actuator 16 is not necessarily Fh = Fi + F
f need not be satisfied, the force obtained by adding the inertial force Fi and the urging force Ff, and the auxiliary force F
It suffices to satisfy the following expression in which the difference from h is equal to or less than the static friction force Fm. | Fh- (Fi + Ff) | ≦ Fm (1)

When the reticle R and the reticle holder H reach a predetermined speed for performing the scanning exposure and move to a constant speed movement (constant speed movement), no acceleration is applied to the reticle R. The driving thrust is reduced to the urging force Ff (see FIG. 6B). Thereby, it is possible to prevent the actuator 16 from applying an impact to the reticle R with a change in the acceleration applied to the reticle holder H (the acceleration corresponding to the thrust Fd → zero), and to balance with the urging force applied by the actuator 17. It is possible to prevent a shear force caused by driving the actuators 16 and 17 from being applied to the reticle R.

In the stationary state and the constant velocity state, the urging forces applied to the reticle R by the actuators 16 and 17 need not always be the same, and the difference between these urging forces is within the static friction force Fm. I just need.

On the other hand, at the time of deceleration after the completion of the scanning exposure, the thrust Fd in the + Y direction is applied to the reticle holder H via the linear motor 15 as shown in FIG.
Is given. At this time, the reticle R has a thrust Fd
(And the mass of the reticle R and the reticle holder H) inertia force Fi acts in the −Y direction. And the control device 1
8 is − with respect to the reticle R by the actuator 16 −
Actuators 16 and 17 are respectively provided so as to apply the urging force Ff in the Y direction and to apply an assisting force Fh in the + Y direction having a magnitude balanced with a force obtained by adding the inertial force Fi and the urging force Ff by the actuator 17. Control individually. Thereby, it is possible to prevent a shearing force exceeding the static frictional force Fm on the holding surface S from being applied to the reticle R with the deceleration of the reticle holder H.

Note that at the time of deceleration as well as at the time of acceleration,
The assisting force Fh applied to the reticle R by the actuator 17 does not necessarily need to satisfy Fh = Fi + Ff, but may satisfy the above expression (1).

As described above, for the reticle R whose position is controlled by being held by the reticle holder H without any relative displacement, the exposure apparatus 1 uses the illumination light for exposure from the illumination optical system IU at the time of exposure. Thus, a predetermined rectangular illumination area on the reticle R is illuminated with uniform illuminance. The wafer holder ST is moved by the drive of the linear motor 33 in synchronization with the reticle R being scanned in the Y direction with respect to this illumination area, so that the exposure area conjugate with respect to this illumination area and the projection optical system PL is moved. To scan the wafer W. As a result, the illumination light transmitted through the pattern area of the reticle R is reduced to 1/4 by the projection optical system PL, and is irradiated onto the wafer W coated with the resist. And
The pattern of the reticle R is sequentially transferred to the exposure area on the wafer W, and the entire pattern area on the reticle R is transferred to the shot area on the wafer W by one scan.

As described above, in the stage apparatus and the exposure apparatus of this embodiment, when the reticle holder H is accelerated or decelerated,
Since the assisting force Fh corresponding to the inertial force Fi of the reticle R is applied to the reticle R, it is possible to prevent a shear force exceeding the static friction force Fm on the holding surface S from acting on the reticle R, and as a result, the relative position of the reticle R The occurrence of displacement can be prevented. Further, in the present embodiment, by disposing the actuators 16 and 17 on both sides in the scanning direction with the reticle R interposed therebetween, the inertial force generated in the scanning direction can be directly and effectively canceled / reduced, and Since the auxiliary force Fh (or the urging force Ff) is applied coaxially along the Y direction, it is possible to prevent a shear force or a moment from acting on the reticle R due to these forces Fh and Ff.

Therefore, the acceleration of the reticle holder H, which had to be suppressed to about 4 G only by the static friction force due to the negative pressure suction as in the related art, is increased to about 10 G in this embodiment, In addition to being able to achieve high-precision positioning and improving the throughput in the exposure apparatus 1, the positioning with respect to the reticle R can be ensured, so that predetermined exposure accuracy such as pattern transfer accuracy can be maintained. it can.

Further, in the present embodiment, when the reticle holder H is accelerated or decelerated, the actuators 16 and 17 are independently controlled to apply the urging force Ff to the reticle R. By separating or contacting the reticle R, it is possible to prevent an impact on the reticle R, and to prevent a relative position shift due to the impact from occurring.

Note that it is preferable to use a linear motor as the actuators 16 and 17 in the above embodiment. In this case, when a force is applied to the reticle R, the actuators 16 and 17 are each driven in a non-contact manner.
Can be prevented from adversely affecting the position controllability. When the reticle R is replaced, the actuators 16 and 17 may be retracted to a position where they do not interfere with the reticle R exchange by a retraction mechanism (not shown) (for example, a linear motor or an air cylinder). Further, a temperature change near the reticle R (the linear motor 15, the actuators 16, 17)
And the like, the exposure accuracy may be degraded. Therefore, it is desirable to flow a temperature-controlled gas (for example, air or nitrogen) in the moving range of the reticle stage 2.

FIGS. 7 and 8 are views showing a stage apparatus and an exposure apparatus according to a second embodiment of the present invention. In these figures, the same elements as those of the first embodiment shown in FIGS.
The description is omitted. The difference between the second embodiment and the first embodiment is that a balance weight device is used as an urging device.

As shown in FIG. 7, on the reticle holder H, the balance weight devices 38 (+ Y side) and 39 (-Y side) are located on both sides of the reticle R in the Y direction. They are arranged at an interval and near the holding unit 22. The balance weight device 38 applies an auxiliary force (or biasing force) in the −Y direction to the side surface of the reticle R along the holding surface S, and the balance weight device 39 applies a force to the side surface of the reticle R. The auxiliary force (or urging force) in the + Y direction is applied along the holding surface S, and these apply the auxiliary force (or urging force) to Y.
It is arranged to be applied coaxially along the direction.

Each of the balance weight devices 38, 39 includes a rotating shaft 38a, 3
9a, rod-shaped support members 38b, 39b rotatably supported around the Z axis with respect to the rotation shafts 38a, 39a, and a weight portion 38 attached to one end of the support members 38b, 39b.
c, 39c, pressing portions 38d, 39d attached to the other ends of the supporting members 38b, 39b sandwiching the rotating shafts 38a, 39a and pressing the side surface of the reticle R, and pressing portions 38d, 39d as shown in FIG. , Toward the reticle R. Reference numerals 38a to 38e indicate that the balance weight device 38 is configured, and 39a to 39e indicate that the balance weight device 39 is configured. In FIG. 8, for convenience, the rotating shafts 38a and 39a are illustrated as being arranged along the X direction.

Hereinafter, these relationships will be described in detail. The mass of the weights 38c, 39c is Mc, and the pressing parts 38d, 39d
Is Md, and the weights 38 from the rotation shafts 38a, 39a
c, the distance to the center of gravity of 39c is Lc;
Ld is the distance from 9a to the center of gravity of the pressing portions 38d and 39d.
And the pressing direction of the compression springs 38e and 39e.
pressing portion 3 against the center of gravity of d, 39d, and reticle R
It is assumed that directions in which forces are applied to 8d and 39d are on the same straight line parallel to the Y axis. Then, the reticle holder H moves in the −Y direction at an acceleration α corresponding to the thrust Fd, and at this time, the pressing portions 38 d and 39 d move from the reticle R to the forces F 38 and F
Let us consider a case where 39 are added.

As shown in FIG. 8A, when the reticle holder H moves in the -Y direction, the center of gravity of the weight 38c is + Y
The inertia force of the magnitude α × Mc acts in the direction, and at the same time, the inertia force of the magnitude α × Md acts in the + Y direction on the center of gravity of the pressing portion 38d. Accordingly, when the counterclockwise rotation of the balance weight device 38 about the rotation axis 38a is defined as positive, α × Mc × Lc−α × Md × Ld + Ff × Ld−F38 × Ld = 0, that is, F38 = Ff + α × (Mc × Lc−Md × Ld) / Ld (2)

Similarly, an inertial force having a magnitude α × Mc acts on the center of gravity of the weight portion 39c in the + Y direction, and an inertial force having a size α × Md acts on the center of gravity of the pressing portion 39d in the + Y direction. Accordingly, the balance formula of the rotational moment about the rotation axis 39a of the balance weight device 39 is α × Mc × Lc−α × Md × Ld−Ff × Ld + F39 × Ld = 0, where F39 = Ff− α × (Mc × Lc−Md × Ld) / Ld (3)

Therefore, the reticle R on which the inertial force Fi acts.
From the equations (2) and (3), the force balancing equation in the Y direction is defined as F38−Ff−F39 = 0, that is, 2α × (Mc × Lc−Md × Ld) / Ld = Ff. 4) Assuming that the mass of the reticle R is MR, Ff = α × MR (5), so that from equations (4) and (5), MR = 2 × (Mc × Lc−Md × Ld) / Ld (6) Becomes

In the state where the equation (6) holds, the reticle R
Does not act in the Y direction. That is, when a reticle R having a prescribed size is used, the weights 38c and 39 are determined according to the mass MR of the reticle R based on Expression (6).
c, the mass Md of the pressing portions 38d, 39d, the distance Lc from the rotating shafts 38a, 39a to the centers of gravity of the weight portions 38c, 39c, and the pressing portions 38d, 3d from the rotating shafts 38a, 39a.
By appropriately selecting the parameters of the distance Ld to the center of gravity of 9d, the inertial force acting on the reticle R can be canceled regardless of the magnitude of the acceleration α.

The urging force F of the compression springs 38e, 39e
When the magnitude of f is smaller than the magnitude of the acceleration α, when the reticle holder H is accelerated or decelerated, the pressing portions 38d and 39d on the side on which the inertial force of the reticle R does not act are applied to the reticle R.
For example, as shown in FIG. 8A, when the reticle holder H moves in the −Y direction, the following condition must be satisfied. Ff + F39> 0 (7) Here, in the equation (3), the force F39 in a state where the urging force Ff is applied is shown, but when the urging force Ff is not applied, F39 = −α × ( Mc × Lc−Md × Ld) / Ld (8) By substituting equation (8) into equation (7), Ff> α × (Mc × Lc−Md × Ld) / Ld (9)

Accordingly, the parameters are appropriately selected so that the equation (9) is satisfied, and the compression springs 38e, 39
If the spring constant and the amount of deflection of e are set, the pressing portion 38 can be used not only at rest and at constant speed but also during acceleration / deceleration.
Since d and 39d do not separate from the reticle R, it is possible to prevent impact on the reticle R and prevent relative displacement from occurring due to the impact (FIG. 8).
(B)).

Then, the balance weight devices 38 and 39 set to the respective parameters satisfying the equations (6) and (9).
When the acceleration such as the start of synchronous scanning, the force of the pressing portion 39d pressing the reticle R becomes weak due to the inertial force of the weight portion 39c,
The force of the pressing portion 38d pressing the reticle R is increased by the inertial force of the weight portion 38c. Then, under the condition where the equation (6) is satisfied, the difference between these forces balances with the inertial force Fi of the reticle R, so that the inertial force Fi (that is, the holding surface S
Is canceled out, and the reticle R is not displaced (see FIG. 8A).

Conversely, at the time of deceleration, the force by which the pressing portion 38d presses the reticle R is weakened by the inertial force of the weight portion 38c, and the force by which the pressing portion 39d presses the reticle R is increased by the inertial force of the weight portion 39c. . Then, under the condition where the equation (6) is satisfied, the difference between these forces balances with the inertial force Fi of the reticle R, so that the inertial force Fi (that is, the shearing force on the holding surface S) is offset, and the reticle R Does not occur (see FIG. 8C).

In this embodiment, the difference between the forces applied to the reticle R by the balance weight devices 38 and 39 does not necessarily need to be balanced with the inertial force Fi of the reticle R. What is necessary is just the static friction force Fm or less.

As described above, also in the stage apparatus and the exposure apparatus of the present embodiment, the static friction force Fm on the holding surface S
Can be prevented from acting on the reticle R, and as a result, relative displacement can be prevented from occurring on the reticle R, and the pressing portions 38d and 39d can be prevented from giving an impact to the reticle R. In addition, it is possible to prevent the occurrence of the relative displacement caused by the impact. Further, the reticle R can be positioned with high accuracy even under high acceleration conditions, so that the throughput of the exposure apparatus 1 can be improved, and a predetermined exposure accuracy can be maintained.

In the above-described embodiment, the suction mechanism for sucking and holding the reticle R on the reticle holder H is provided with the actuators 16 and 17 and the balance weight devices 38 and 39 so that the suction force can be made weaker than before. Alternatively, the suction mechanism itself may be eliminated.

In the above embodiment, the stage device of the present invention is used as a reticle stage, but may be used for a wafer stage. in this case,
It is possible to prevent the relative displacement of the wafer W from occurring due to the acceleration / deceleration of the wafer stage. Furthermore, in the above embodiment, the stage apparatus of the present invention is configured to be applied to the exposure apparatus 1. However, the present invention is not limited to this. The present invention is also applicable to various precision measuring devices such as a transfer mask drawing device and a mask pattern position coordinate measuring device. Further, in the above-described embodiment, the substrate such as the reticle R is suction-held by negative pressure suction. However, the present invention can be applied to a case where the substrate is held by a method such as an electrostatic chuck.

The substrate of the present embodiment is not limited to a semiconductor wafer W for a semiconductor device, but also a glass substrate for a liquid crystal display device, a ceramic wafer for a thin film magnetic head, or a mask or a mask used in an exposure apparatus. Reticle master (synthetic quartz, silicon wafer)
Etc. are applied.

The exposure apparatus 1 includes a step-and-scan type scanning exposure apparatus (scanning stepper; US Pat. No. 5,473,410) for scanning and exposing the pattern of the reticle R by synchronously moving the reticle R and the wafer W. To
The present invention can also be applied to a step-and-repeat type projection exposure apparatus (stepper) that exposes the pattern of the reticle R while the reticle R and the wafer W are stationary and sequentially moves the wafer W stepwise.

The type of the exposure apparatus 1 is not limited to an exposure apparatus for manufacturing a semiconductor device for exposing a semiconductor device pattern onto a wafer W, but may be an exposure apparatus for manufacturing a liquid crystal display element, a thin film magnetic head, an image pickup device (CCD). Alternatively, the present invention can be widely applied to an exposure apparatus for manufacturing a reticle and the like.

As the light source of the illumination light for exposure, a bright line (g-line (436 nm), h
Line (404.7 nm), i-line (365 nm)), KrF
Not only an excimer laser (248 nm), an ArF excimer laser (193 nm), and an F ₂ laser (157 nm) but also a charged particle beam such as an X-ray or an electron beam can be used. For example, when using an electron beam, thermionic emission type lanthanum hexaborite (LaB ₆ ) or tantalum (Ta) can be used as the electron gun. When an electron beam is used, a configuration using a reticle R may be used, or a configuration may be used in which a pattern is directly formed on a wafer without using the reticle R. Alternatively, a high frequency such as a YAG laser or a semiconductor laser may be used.

The magnification of the projection optical system PL may be not only a reduction system but also an equal magnification system or an enlargement system. Further, as a projection optical system PL, when far ultraviolet rays such as excimer laser are used, a material that transmits far ultraviolet rays such as quartz or fluorite is used as a glass material, and when an F ₂ laser or X-ray is used, a catadioptric system or An optical system of a refraction system (a reticle R of a reflection type is also used). When an electron beam is used, an electron optical system including an electron lens and a deflector may be used as the optical system. It is needless to say that the optical path through which the electron beam passes is in a vacuum state. Further, the present invention can also be applied to a proximity exposure apparatus that exposes the pattern of the reticle R by bringing the reticle R and the wafer W into close contact without using the projection optical system PL.

A linear motor (see US Pat. No. 5,623,853 or US Pat. No. 5,528,118) is mounted on the wafer stage 5 and the reticle stage 2.
Is used, any of an air levitation type using an air bearing and a magnetic levitation type using Lorentz force or reactance force may be used. In addition, each stage 2, 5
May be a type that moves along a guide or a guideless type that does not have a guide.

As a driving mechanism of each of the stages 2 and 5, a magnet unit (permanent magnet) having a two-dimensionally arranged magnet and an armature unit having a two-dimensionally arranged coil are opposed to each other, and each stage 2 and 5 is driven by electromagnetic force. 5 may be used. In this case, one of the magnet unit and the armature unit may be connected to the stages 2 and 5, and the other of the magnet unit and the armature unit may be provided on the moving surface side (base) of the stages 2 and 5.

As described above, the exposure apparatus 1 of the present embodiment
Is a system that includes various components including the components listed in the claims of the present application, with predetermined mechanical accuracy, electrical accuracy,
It is manufactured by assembling to maintain optical accuracy. Before and after this assembly, adjustments to achieve optical accuracy for various optical systems, adjustments to achieve mechanical accuracy for various mechanical systems, and various electric systems to ensure these various accuracy Are adjusted to achieve electrical accuracy. The process of assembling the various subsystems into the exposure apparatus includes mechanical connection, wiring connection of an electric circuit, and piping connection of a pneumatic circuit between the various subsystems. It goes without saying that there is an assembling process for each subsystem before the assembling process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustment is performed, and various precisions of the entire exposure apparatus are secured. It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

As shown in FIG. 9, for a semiconductor device, a step 201 for designing the function and performance of the device, a step 202 for manufacturing a mask (reticle) based on the design step, a step 203 for manufacturing a wafer from a silicon material A wafer processing step 204 of exposing a reticle pattern to a wafer by the exposure apparatus 1 of the above-described embodiment, a device assembling step (dicing step,
(Including a bonding step and a package step) 205, an inspection step 206, and the like.

[0078]

As described above, the stage apparatus according to the first aspect controls the force applied to the substrate along the holding surface based on the inertial force of the substrate accompanying the movement of the moving body. ing. Thus, in this stage device, it is possible to prevent a shear force exceeding the static friction force on the holding surface from acting on the substrate, and as a result, it is possible to prevent the relative displacement of the substrate from occurring.

The stage device according to a second aspect has a structure having first and second urging devices arranged so as to sandwich the substrate. Thus, in this stage device, the inertial force generated in the moving direction can be directly and effectively canceled / reduced, and the force is applied coaxially along the moving direction. Therefore, it is possible to prevent the shearing force and the moment from acting on the substrate.

The stage device according to claim 3 is configured to control the first and second urging devices independently when the moving body is accelerating and when it is decelerating. Thus, in this stage device, it is possible to prevent the first and second urging devices from applying an impact to the substrate during acceleration and deceleration, and to prevent the occurrence of a relative position shift due to the impact. To play.

The stage device according to claim 4 is configured to control the first and second urging devices to apply a predetermined urging force to the substrate when the moving body moves at a constant speed. Thus, in this stage device, it is possible to prevent the first and second urging devices from applying an impact to the substrate during the constant-speed movement, and to prevent the occurrence of a relative displacement caused by the impact. It works.

The stage device according to claim 5 is configured such that the biasing device is a linear motor. This allows
The stage device has an effect that it is possible to prevent the position controllability of the substrate from being adversely affected by disturbance such as vibration accompanying the driving of the urging device.

According to a sixth aspect of the present invention, there is provided an exposure apparatus wherein the stage device according to any one of the first to fifth aspects is used as at least one of a mask stage and a substrate stage. Thus, in this exposure apparatus, it is possible to position the substrate with high accuracy even under high acceleration conditions, so that it is possible to improve the throughput of the exposure apparatus and to maintain a predetermined exposure accuracy.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention, and is a schematic configuration diagram of an exposure apparatus having a stage device.

FIG. 2 is an external perspective view of a reticle stage according to the first embodiment.

FIG. 3 is a cross-sectional view of a reticle holder that holds a reticle.

FIG. 4 is a control block diagram of the exposure apparatus.

FIG. 5 is an external perspective view of a wafer stage included in the exposure apparatus.

FIG. 6 (a) according to the first embodiment is for acceleration.
(B) is a diagram showing the force acting on the reticle at the time of constant speed, and (c) is a diagram showing the force acting on the reticle at the time of deceleration.

FIG. 7 is an external perspective view of a reticle stage according to a second embodiment.

FIG. 8 (a) according to a second embodiment during acceleration,
(B) is a diagram showing the force acting on the reticle at the time of constant speed, and (c) is a diagram showing the force acting on the reticle at the time of deceleration.

FIG. 9 is a flowchart illustrating an example of a semiconductor device manufacturing process.

FIG. 10 is a cross-sectional view for explaining a conventional reticle holding method.

11 is a diagram showing a force acting on the reticle in FIG.

FIG. 12 is a plan view of FIG.

FIG. 13 is a cross-sectional view for explaining a conventional reticle holding method.

14 is a cross-sectional view for explaining a holding principle in FIG.

[Explanation of symbols]

 S holding surface H reticle holder (moving body) R reticle (mask, substrate) W wafer (photosensitive substrate) 1 exposure apparatus 2 reticle stage (mask stage) 4 stage device 5 wafer stage (substrate stage) 16 actuator (biasing device, 1st urging device) 17 Actuator (urging device, 2nd urging device) 18 Control device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F078 CA02 CA08 CB09 CB12 CC01 CC11 5F031 CA01 CA02 CA05 CA07 HA02 HA13 HA16 HA24 HA27 HA29 HA30 HA53 HA55 JA02 JA06 JA14 JA17 JA32 KA06 KA08 LA03 LA04 LA07 LA08 MA27 5F046 CC03 CC13 CC18

Claims (6)

[Claims] 1. A stage device comprising a moving body that moves while holding a substrate on a holding surface, wherein the urging device applies a force to the substrate along the holding surface; A control device for controlling the urging device based on the accompanying inertial force of the substrate. 2. The stage device according to claim 1, wherein the urging device has first and second urging devices arranged so as to sandwich the substrate. 3. The stage device according to claim 2, wherein the control device controls the first and second urging devices independently during acceleration and deceleration of the moving body. Stage equipment. 4. The stage device according to claim 2, wherein the control device controls the first and second urging devices to apply a predetermined urging force to the substrate when the moving body moves at a constant speed. A stage device characterized by controlling. 5. The stage device according to claim 1, wherein the urging device is a linear motor. 6. An exposure apparatus for exposing a pattern of a mask held on a mask stage to a photosensitive substrate held on a substrate stage, wherein at least one of the mask stage and the substrate stage is used. An exposure apparatus using the stage device described in any one of the above.