JPH07335538A - Stage device - Google Patents

Abstract

PURPOSE:To improve the throughput of a stage device as a whole by preventing the positional deviation between a table and base supported by a vibration isolator even when the base shakes caused by the driving of the table. CONSTITUTION:The relative positional deviation between a base 3 and table 7 caused by the shaking of the base 3 when the table 7 is driven by means of a first driving means 4Y is corrected by driving second driving means 22Y and 23Y which move the table 7 in the direction along the driving shaft 5Y of the table 7 with the driving force corresponding to the acceleration of the table 7 when the table 7 is driven by means of the first driving means 4Y so that the acceleration corresponding to the shaking of the base 3 can be applied to the table 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage device, and is particularly applicable to an exposure device used for manufacturing semiconductor elements, liquid crystal substrates, thin film magnetic heads and the like.

[0002]

2. Description of the Related Art Conventionally, a projection exposure apparatus for exposing a pattern image of a reticle (photomask, etc.) onto a photosensitive substrate via a projection optical system has been used in a lithographic process for manufacturing a semiconductor device or a liquid crystal substrate. To be done. In this projection exposure apparatus, a photosensitive substrate (wafer) is placed and
It has a stage device that can move the photosensitive substrate two-dimensionally. Then, the stage device is controlled and positioned at a predetermined position to position the reticle and the wafer for exposure. Further, this type of projection exposure apparatus is provided on a vibration isolation table in order to prevent the positioning accuracy between the reticle and the wafer from being adversely affected by vibration from the ground (outside the apparatus). The anti-vibration table damps vibrations from the outside of the device by means of elastic bodies and elastic bodies.

FIG. 7 shows a schematic structure of the projection exposure apparatus 1. In the stage device 2 used in the conventional projection exposure apparatus 1 for manufacturing semiconductors, the vibration isolation table 3 that constitutes the substrate is used.
The motor 4 installed on the stage is controlled by a stage controller (not shown).
Is driven, the table 7 guided by the guide mechanism 6 via the feed screw (drive shaft) 5 is driven to a predetermined position. A wafer W, which is a photosensitive substrate, is placed on the table 7, and light emitted from a light source 8 is emitted to a desired exposure area on the wafer surface. An illumination optical system 9 including a lens system such as a fly-eye lens and a condenser lens, The mask pattern is focused through the reticle 10 and the projection lens 11, and the mask pattern is imaged on the wafer W. After the projection exposure of the exposure area is completed, the table 7 is appropriately driven so that the next exposure area is positioned at a predetermined position within the projection field of the projection lens 11. The interferometer 12 measures the position of the table 7 based on the reflected light from the movable mirror 13 provided on the table 7.

In the stage apparatus 2 of the projection exposure apparatus 1 as described above, the entire apparatus except the table 7 is fixed as a rigid body on the anti-vibration table 3, and the table 7 is provided by the feed screw 5 and the guide mechanism 6 of the table 7. It is fixed to the body as a rigid body. In other words, although the table 7 and the device are macroscopically integrated, comparing the rigidity of the entire device with the supporting rigidity of the table 7 shows that microscopically, the table 7 is spring-supported on the base. It is equivalent to a structural model. This is because the feed screw 5 is not regarded as a perfect rigid body due to the play and friction of the joint portion in the accuracy required here.

Therefore, as the table 7 is driven (decelerated or stopped), the entire apparatus except the table 7 is shaken (vibrated). That is, the reaction force of the driving force that acts on the table 7 acts on the anti-vibration table 3, and the entire device except the table 7 shakes. However, since only the table 7 tries to stay in the original position due to the inertial force, it is caused by so-called shaking between the entire apparatus and the table 7, that is, between the vibration isolating table 3 which is the base and the table 7. Misalignment occurs.

[0006]

As described above, the stage device 2 used in the conventional projection exposure apparatus 1 for manufacturing semiconductors.
Then, when driving the table 7 to move it to a predetermined position,
Shaking occurred in the entire apparatus, and a positional deviation caused by the shaking occurred between the vibration isolation table 3 and the table 7. As described above, since the optical system for projection exposure is fixed to the substrate as a rigid body, the positional deviation between the projection optical system and the wafer W placed on the table 7 is the projection exposure apparatus 1. Adversely affect the performance of. For this reason, it is necessary to perform projection exposure while the vibration is naturally attenuated and the shake is sufficiently reduced, which causes a problem that the throughput is significantly reduced in the entire exposure process.

The present invention has been made in consideration of the above points, and even if the table is shaken by the driving of the table on the base supported by the vibration isolator, the positional deviation between the table and the base is caused. It is intended to realize a stage device capable of improving the throughput as a whole by preventing the above.

[0008]

In order to solve such a problem, according to the present invention, a base (3) supported by an anti-vibration device and a base (3) via a drive shaft (5) are provided. A rigidly supported table (7) and its table (7)
A stage device (21) having a first driving means (4) for positioning the substrate at a predetermined position on the base (3),
Second drive means (22, 23) for moving the table (7) in a direction along the drive shaft (5) of the table (7)
And acceleration measuring means (12, 13, 24) for measuring the acceleration of the table (7) when the table (7) is driven by the first driving means (4), and the acceleration measuring means (1
A driving force generating means (24) for generating the driving force of the second driving means (22, 23) in accordance with the acceleration of the table (7) measured in 2, 13, 24), and the first driving means. The base (3) and the table (7) caused by the shaking of the base (3) that occurs when driving the table (7) in (4)
In order to correct the relative positional deviation between the second driving means (22, 23), the second driving means (22, 23) is driven by the driving force so that the table (7) is provided with an acceleration corresponding to the shaking of the base (3). did.

[0009]

The second drive means (2) for moving the table (7) in the direction along the drive shaft (5) of the table (7).
2, 23) by the first drive means (4) on the table (7)
It is driven by a driving force corresponding to the acceleration of the table (7) when driving the table (7), and the acceleration corresponding to the shaking of the board (3) is given to the table (7).
The relative displacement between the base (3) and the table (7) due to the shaking of the base (3) that occurs when the table (7) is driven by the driving means (4) of FIG. Even if the table (7) is shaken by the drive of the table (7) on the base (3) supported by the shaking device, the positional displacement between the table (7) and the base (3) is prevented in advance. The overall throughput can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 in which parts corresponding to those in FIG.
In FIG. 1, reference numeral 20 generally indicates a schematic configuration of a projection exposure apparatus in which a stage device 21 according to the present invention is used. In the case of this embodiment, a second unit for moving the table 7 in the direction along the feed screw 5 is provided between the table 7 and the vibration isolation table 3.
The linear motor mechanisms 22 and 23 are arranged as the driving means.

FIG. 2 is a perspective view of the stage device 21, in which a stage device movable in the X direction and a stage device movable in the Y direction are combined so that the table 7 can move freely in a horizontal plane. It is done like this. Actually, the table 7 is an X table 7X movable in the X direction, and a Y table.
It has a Y table 7Y that can move in any direction. The X table 7X is provided on the Y table 7Y. The X table 7X is supported on the Y table 7Y by a non-contact type guide mechanism (air bearing or the like) 6X extending in the X direction. The Y table 7Y that supports the X table 7X is provided on the vibration isolation table 3. The Y table 7Y is supported on the vibration isolation table 3 by a non-contact type guide mechanism (air bearing or the like) 6Y extending in the Y direction.

The Y table 7Y is driven in the Y direction by a feed screw 5Y provided in parallel with the guide mechanism 6Y. The feed screw 5Y is driven by a motor 4Y attached on the vibration isolation table 3. Linear motor mechanisms 22Y and 23Y are provided between the Y table 7Y and the vibration isolation table 3. Further, the X table 7X is driven in the X direction by the feed screw 5X provided in parallel with the guide mechanism 6X. The feed screw 5X is driven by a motor 4X mounted on the Y table 7Y. X table 7X and Y
Between the table 7Y, the linear motor mechanism 22X, 2
3X is provided.

The laser interferometer 12Y is adapted to detect the position of the Y table 7Y with high precision, and actually irradiates the reflecting mirror 13Y provided on the X table 7X with laser light, and based on the return light thereof. The position of the Y table 7Y is measured without contact. The laser interferometer 12X is an X table 7
The position of X can be detected with high accuracy, and the reflecting mirror 13X provided on the X table 7X is irradiated with laser light similarly to the laser interferometer 12Y, and the X table is non-contact based on the returned light. Measure the 7X position. 2, the laser interferometer 12Y is fixed on the vibration isolation table 3, and the laser interferometer 12X is fixed on the Y table 7Y.

Here, paying attention to the fact that the linear motor mechanisms 22X and 23X for driving the X table 7X in the X direction and the linear motor mechanisms 22Y and 23Y for driving the Y table 7Y in the Y direction have the same basic structure, FIG. 3 shows linear motor mechanisms 22X and 23 for driving the X table 7X in the X direction.
X will be described. The linear motor mechanisms 22X and 23X provided between the X table 7X and the Y table 7Y include a stator 22X attached to the Y table 7Y side and a mover 23 attached to the Y table 7Y side of the X table 7X.
It is composed of X and. Also in the Y direction, linear motor mechanisms 22Y and 23Y are similarly provided between the Y table 7Y and the vibration isolation table 3 (FIG. 1).

The stage device 21 further includes a controller 24.
have. The controller 24 receives the table position information measured by the laser interferometers 12X and 12Y in cooperation with the reflecting mirrors 13X and 13Y, and receives the motors 4X and 4Y and the feed screw 5.
X, 5Y or linear motor mechanism 22X, 2
The tables 7X and 7Y are appropriately driven via 3X and 22Y and 23Y. The controller 24 controls all of these other devices.

In the above structure, when the stage device 21 according to this embodiment is used in the projection exposure apparatus 20 for semiconductor manufacturing, the table 7 on which the wafer W, which is a photosensitive substrate, is placed is exposed after the projection exposure. The exposure area is driven so that it is positioned at a predetermined position in the projection field of the projection optical system. Specifically, the controller 24 receives the current position information and the target position information, and the motors 4X, 4Y and the feed screws 5X, 5
The tables 7X and 7Y are quickly moved to the target position via Y. At this time, the tables 7X and 7Y receive a positive acceleration motion, a constant velocity motion, and a negative acceleration motion. Less than,
For convenience, the vibration and vibration isolation in the X direction in the stage device 21 will be described.

Since acceleration acts on the X table 7X via the motor 4X and the feed screw 5X, as a reaction thereof, the reaction force is transmitted to the Y table 7Y to which the motor 4X and the feed screw 5X are attached. As a result, the entire apparatus except the X table 7X vibrates and shakes. X table 7X
Is supported by the non-contact type guide mechanism 6X and the feed screw 5X on the Y table 7Y, so that the X table 7X tries to stay in the original position independently of the swinging motion of the entire apparatus. Inertial force will work.

The X table 7X is a guide mechanism 6X,
Although it tries to move integrally with the entire apparatus via the feed screw 5X, the X table 7X does not completely follow the entire apparatus because the feed screw 5X and the like are not a completely rigid body. Therefore,
In the controller 24 of this embodiment, a thrust generator (a high-pass filter described later) for generating thrust commands for the linear motor mechanisms 22X and 23X is provided inside, and the table 7X and the acceleration in the X direction of the Y table 7Y are also provided. The same acceleration is applied in real time via the linear motor mechanisms 22X and 23X. As a result, during the movement of the X table 7X, relative displacement between the X table 7X and the Y table 7Y due to shaking does not occur. Therefore, it is as if the table 7X is driven by the motor 4X and the feed screw 5X and stopped at the target position, and the next exposure can be performed without waiting for the vibration of the apparatus to subside.

It should be noted that, in reality, the fact that the reaction force against the drive of the table 7 causes a positional deviation due to the shaking between the vibration isolation table 3 and the table 7 is corrected, and the positional deviation is corrected and eliminated. In order to achieve this, the table 7 can be made to follow the swinging motion of the base. Therefore, if the same acceleration as that of the base is applied to the table 7 in real time, the relative displacement between the base and the table 7 will occur. I found that I can correct

Here, the relationship from the acceleration a ₁ of the table 7 to the thrust F of the linear motor mechanisms 22 and 23 is that the mass of the table 7 is m, the mass of the entire device excluding the table 7 is M, and the viscous drag coefficient is B and the spring constant can be expressed as a block diagram as shown in FIG. 4, where k is the following equation.

[Equation 1] Of the secondary high-pass filters represented by, it is equivalent to one having a high sharpness (Q) at a specific frequency. Therefore, in this embodiment, this high-pass filter is realized by an electric circuit (shown in FIG. 6 described later). However, in equation (1),
A, B, and C are constants determined by the mass m of the table 7, the mass M of the entire apparatus, the viscous drag coefficient B, and the spring constant k, and s is a Laplace operator.

The thrust F (t) generated as a result is generated by the linear motor mechanisms 22 and 23 and applied to the table 7, and the table 7 is forcibly applied with the same acceleration as the base acceleration a (t). Therefore, the table 7 can be made to completely follow the shaking of the base. For example, in a DC linear motor, the generated thrust _FL is the thrust constant k peculiar to the linear motor.
And the current i, that is, _FL = k × i. Therefore, by appropriately controlling the current i, it is possible to easily apply a desired thrust to the table 7.

In practice, the thrust generator provided in the control unit 24 can be realized as the secondary high-pass filter (shown in FIG. 6) described above. For example, in FIG. 4, the mass m of the table is 165 [kg], and the mass M of the entire device excluding the table is M.
Is 1390 [kg], and the viscous resistance coefficient B is 2 × 10 ⁴ [N / (m
/ SEC)], and the spring constant k is 1.37 × 10 ⁶ [N / m], the transfer function HPF (s) of the secondary high-pass filter
Is the expression

[Equation 2] And G (s) has the frequency characteristic shown in FIG. From this HPF (s) is a gain = 19.6, Q = 2.18, f c =
Since it can be regarded as substantially equivalent to 5 [Hz], it can be realized by the circuit configuration as shown in FIG. In the case of FIG. 6, for example, the capacitor C ₁ is 1 [μF] and the resistors R ₁ , R ₂ , R _in , and R _f.
Are selected as 7.32, 140, 10, and 196 [kΩ], respectively.

The acceleration a ₁ (t) of the table 7 input to the high-pass filter circuit is obtained by taking the positional information of the table 7 measured by the laser interferometer into the controller 10 at a constant sampling interval Δt,

[Equation 3] It is obtained by outputting the calculation result represented by the following through the D / A converter. However, in the equation (3), x
_k , x _k-1 , and x _k-2 indicate the position information acquired at the kth, k-1, and k-2th samplings, respectively.

[0025] the linear motor mechanism 22X, as generated thrust F _L of 23X is always equal to the thrust command F of the thrust generator (t), a linear motor mechanism 22X, the current i according to the 23X to the controller 24 This is appropriately controlled (Fig. 3). Also in the Y direction, as in the case of the X direction, the controller 2
Reference numeral 4 controls the linear motor mechanisms 22Y and 23Y. However, since the Y table 7Y moves integrally with the X table 7X, the mass of the Y table 7Y here is the X table 7Y.
The sum of the mass m ₂ of the X mass m ₁ and Y table 7Y.
Therefore, the force F (t) applied to the Y table 7Y is given by the following equation, where the acceleration of the vibration isolation table 3 is a ₂ (t).

[Equation 4] Becomes

According to the above construction, the same acceleration as the acceleration of the base is forcibly applied to the table so that the table completely follows the shake of the base. Since there is no misalignment between the table and the substrate, it is possible to perform projection exposure after stopping in the next exposure area without waiting for the attenuation of the shake as in the conventional case, thus dramatically improving the throughput of exposure processing. Improve to.

Further, according to the above-mentioned configuration, since the acceleration given to the table is obtained from the acceleration of the board through the high-pass filter having the hardware configuration, the configuration is remarkably compared with the case where the acceleration is obtained by software. In addition, the responsiveness can be improved and the throughput can be improved by not requiring software calculation.

In the above embodiment, the linear motor mechanism is used as a means for correcting the positional deviation between the table and the vibration isolation table due to the shaking, but the stop position of the table and the target position are the same. When not in use, it can be used as a fine movement means for finely moving the table, or as a deceleration means (damper) for promoting settling of shaking.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the stage device used in the projection exposure apparatus for semiconductor manufacturing has been described, but the present invention is not limited to this, and for example, projection for liquid crystal manufacturing. It is suitable for wide application to other general stage devices such as exposure devices and precision machine tools.

[0030]

As described above, according to the present invention, the table is moved in the direction along the drive shaft of the table.
Driving means for driving the table by a driving force corresponding to the acceleration of the table when the table is driven by the first driving means,
By providing the table with an acceleration corresponding to the shake of the base, it is possible to correct the relative positional deviation between the base and the table due to the shake of the base that occurs when the table is driven by the first drive means. Thus, even if the table is shaken by the driving of the table on the base supported by the vibration isolator, the displacement between the table and the base is prevented in advance, and the stage in which the throughput is improved as a whole. The device can be realized.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a projection exposure apparatus in which a stage device to which the present invention is applied is used.

FIG. 2 is a schematic perspective view showing the configuration of the stage device shown in FIG.

FIG. 3 is a schematic diagram for explaining the operation of the linear motor in the stage device of FIG.

FIG. 4 is a block diagram showing the relationship between the acceleration of the table and the thrust of the linear motor as a transfer characteristic.

5 is a characteristic curve diagram showing characteristics of G (S) in a high-pass filter according to the transfer characteristics of FIG.

FIG. 6 is a connection diagram showing a circuit configuration for realizing the characteristics of the high-pass filter of the formula (2).

FIG. 7 is a schematic diagram showing a schematic configuration of a stage device used in a conventional projection exposure apparatus for semiconductor manufacturing.

[Explanation of symbols]

1, 20 ... Projection exposure apparatus, 2, 21 ... Stage apparatus, 3 ... Vibration isolation table, 4X, 4Y ... Motor, 5X, 5Y
...... Feed screw, 6X, 6Y …… Guide mechanism, 7X, 7Y
... table, 8 ... light source, 9 ... illumination optical system, 10 ...
… Reticle, 11 …… Projection lens, 12X, 12Y ……
Laser interferometer, 13X, 13Y ... Reflector, 22X, 2
2Y ... Stator, 23X, 23Y ... Mover, 24 ...
Controller.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 21/68 K

Claims (4)

[Claims] 1. A base supported by an anti-vibration device, a table substantially rigidly supported by the base via a drive shaft, and a first for positioning the table at a predetermined position on the base.
And a second driving means for moving the table in a direction along the drive axis of the table, and a table for driving the table by the first driving means. The first driving means includes an acceleration measuring means for measuring acceleration, and a driving force generating means for generating a driving force of the second driving means according to the acceleration of the table measured by the acceleration measuring means. In order to correct the relative displacement between the base and the table due to the shaking of the base that occurs when driving the table, the second driving means is driven by the driving force,
A stage device, wherein an acceleration corresponding to the shaking of the base is applied to the table. 2. The stage apparatus according to claim 1, wherein the second driving means is a linear motor mechanism provided between the base and the table. 3. The acceleration measuring means fetches a detection value of a position detection sensor for detecting the position of the table at predetermined intervals, calculates a second-order difference of the detection value, measures the acceleration of the table, and accelerates the acceleration. The stage device according to claim 1, wherein a signal is transmitted. 4. The driving force generating means filters the acceleration signal input from the acceleration measuring means with a high-pass filter having a high sharpness at a specific frequency, and the second acceleration based on the acceleration of the table. The stage device according to claim 3, wherein the driving force of the driving means is generated.