JP2001146940A - Active vibration resistant device, method therefor, and device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of vibration control performance, in such a case where a mounted object on a vibration resistant table is an apparatus for moving on the vibration resistant table, and in such a case where a gravity center position is not different from a designed position by size error and assembly error. SOLUTION: This active vibration resistant device is provided with a vibration resistant table 1 mounted with an object 3 under vibration resistance, a plurality of supporting mechanisms 2 vibration-resistantly supporting the vibration resistant table and having an actuator for applying controlling force to the vibration resistant table, a plurality of vibration detecting means 4 for detecting vibration of the vibration resistant table, an extracting means 5 for extracting a vibration signal of a prescribed operating mode of the vibration resistant table on the basis of an output signal of a plurality of vibration detecting means, a compensation calculating means 6 for executing prescribed compensation to an output of the extracting means, and a distribution means for distributing the compensation signal of each operating mode obtained by the compensation calculating means as a driving signals of each actuator. In the active vibration resistant device, a calculating method of the extracting means and the distributing means is changed on the basis of a gravity center position of the vibration resistant table or a construction body formed by assembling the vibration resistant table with the object under vibration resistant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active anti-vibration apparatus for mounting on precision equipment, which has greatly improved anti-vibration characteristics with respect to vibration transmitted from an installation base, an active anti-vibration method, and a device manufacturing method using the same. About.

[0002]

2. Description of the Related Art As precision instruments such as an electron microscope and a semiconductor exposure apparatus have become more precise, there has been a demand for higher performance of a precision anti-vibration apparatus equipped with them. In particular, in the case of a semiconductor exposure apparatus, in order to perform appropriate and quick exposure, a vibration isolation table that eliminates as much as possible external vibrations such as vibrations from a floor or other equipment installation foundation is necessary. There are strict requirements for vibration performance and vibration suppression performance for vibration generated by the operation of equipment mounted on the vibration isolation table, and a more sophisticated vibration isolation device is indispensable.

In response to such a demand, the vibration of the vibration isolation table is detected by a vibration sensor, the output signal is compensated, and the output signal is fed back to an actuator for applying a control force to the vibration isolation table, so that the vibration is actively detected. 2. Description of the Related Art An active vibration isolation device that controls vibration of a vibration isolation table has been put to practical use. Active anti-vibration devices enable a balanced realization of anti-vibration performance and vibration control performance, which was difficult with conventional anti-vibration devices consisting only of passive anti-vibration elements such as springs and dampers. .

In these devices and their control methods, a control loop is formed independently for each set of a vibration sensor disposed on a vibration isolation table and an actuator disposed closest to the vibration sensor, and vibration, position and It is common to perform attitude control. That is, a method of forming an independent control loop in each part of the vibration isolation table has been adopted.

However, in the active vibration isolator controlled by this method, the parameters in the control loop formed in each part of the vibration isolation table and the behavior of each motion mode such as translation and rotation of the vibration isolation table are one-to-one. Does not correspond to Therefore, it is not easy to design and adjust the control parameters while paying attention to the stability and control performance of the control system. In other words, in this method, the control systems independently adjusted in each part of the vibration isolation table interfere with each other, so that the control parameters are adjusted and the motion characteristics of the vibration isolation device are arbitrarily adjusted to improve the vibration control performance. It was difficult.

In order to solve such a problem, a vibration isolator that performs vibration control for each motion mode such as translation and rotation of the vibration isolator has been proposed, and its effectiveness has been confirmed. FIG.
1 shows a configuration example of an active vibration isolation device that controls this conventional vibration isolation table for each motion mode. As shown in the drawing, in the vibration damping device, information on each motion mode such as translation and rotation of the vibration damping table 1 is extracted from the output of the vibration sensor 4 by the motion mode extracting means 5, and the extracted result is Compensation calculation is performed by the compensation calculation means 6 for each exercise mode. Then, the obtained compensation signal for each motion mode is distributed to actuators in each support mechanism 2 for applying a control force to the vibration isolation table 1 by using the thrust distribution means 7. Each actuator is driven by the drive circuit 12 based on the output signal of the thrust distributor 7.

In such an active vibration isolator, control parameters can be designed and adjusted by focusing on the motion mode of the vibration isolation table, that is, the motion characteristics of the entire vibration isolation table. Therefore, control parameters can be easily designed and adjusted.

In order to control the anti-vibration table for each motion mode in this manner, the behavior of each of the motion modes of the anti-vibration table is ensured with sufficient accuracy, and each of the actuators corresponding to the drive signal of each of the motion modes is controlled. Thrust must be properly distributed to the vehicle. For that purpose, it is necessary to accurately perform the calculations by the motion mode extracting means and the thrust distribution means. These calculations are performed based on the position of the center of gravity of the vibration isolation table and the positions of the sensors and actuators.

[0009]

However, according to such a conventional active anti-vibration apparatus, the mounting of the anti-vibration table is X.
In the case of a device that moves on an anti-vibration table such as a Y stage, since the position of the center of gravity changes with the movement of the load,
A deviation occurs between the actual value and the calculation result of the motion mode extraction means and thrust distribution means based on the arithmetic expression determined based on the center of gravity obtained from the static arrangement of the load, and the vibration control performance is deteriorated. There is.

[0010] In addition, since there is a dimensional error or an assembly error in the vibration damping table or the mounted object, it is not possible to easily obtain an accurate position of the center of gravity. A deviation may occur between the calculation result of the motion mode extraction unit and the thrust distribution unit and the actual value, which may deteriorate the vibration control performance.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, an object of the present invention is to provide an active vibration isolator, a method, and a device manufacturing method in which a mounted object of the vibration isolation table is an apparatus that moves on the vibration isolation table. It is another object of the present invention to prevent the vibration control performance from deteriorating even when the position of the center of gravity is different from the designed position due to a dimensional error or an assembly error.

[0012]

In order to achieve this object, a first active vibration isolator according to the present invention includes a vibration isolation table on which an object to be subjected to vibration isolation is mounted, and a vibration isolating support for the vibration isolation table. A plurality of support mechanisms having an actuator for applying a control force to the anti-vibration table, a plurality of vibration detecting means for detecting vibrations of the anti-vibration table, and the anti-vibration based on output signals of the plurality of vibration detecting means. Extraction means for extracting a vibration signal of a predetermined motion mode of the table, compensation calculation means for performing a predetermined compensation on the output of the extraction means, and a compensation signal of each motion mode obtained by the compensation calculation means for each actuator. Distributing means for distributing as a drive signal, wherein a calculation method of the extracting means and the distributing means is changed based on the position of the center of gravity of the vibration isolation table or a structure in which the vibration isolation table and the target are combined. I do.

According to a second active vibration isolator of the present invention, in the first active vibration isolator, the actuator is a pneumatic actuator, and the position of the center of gravity is maintained at a predetermined position by the pneumatic actuator. In this case, it is determined based on the pressure of the pneumatic actuator necessary to perform the operation.

Further, in the active vibration isolation method of the present invention, a step of detecting vibrations at a plurality of locations on the vibration isolation table and a step of extracting a vibration signal of a predetermined motion mode of the vibration isolation table based on the detection result. Applying a predetermined compensation to the extracted vibration signal of each motion mode; and controlling the vibration signal of each of the motion modes subjected to compensation to the vibration isolation table while controlling the vibration isolation table. And distributing as a drive signal to a plurality of actuators, and the vibration signal of the motion mode based on the position of the center of gravity of the vibration isolating table or the structure including the vibration isolating table and the vibration isolation target thereon. Changing a calculation method for performing extraction and distribution.

[0015] The device manufacturing method of the present invention comprises the steps of: supporting the substrate stage, the projection optical system, or the original plate stage of the exposure apparatus in a vibration-proof manner by the active vibration-removing method of the present invention; Exposing the pattern on the original plate on the original stage to the substrate on the substrate stage via the projection optical system.

In the configuration of the present invention, a vibration signal for each motion mode is extracted and distributed based on the position of the center of gravity of a vibration isolating table or a structure in which a vibration isolating table and an object to be vibration isolating are combined. Because the calculation method was changed,
If the object to be removed moves on the table and the center of gravity of the combined weight changes, or if the position of the center of gravity differs from the designed one due to dimensional errors or assembly errors, By the calculation method appropriately changed, the vibration signals of each motion mode corresponding to the exact position of the center of gravity are extracted and distributed. Therefore, deterioration of the vibration control performance is prevented.

[0017]

FIG. 1 is a block diagram showing a configuration of an active vibration isolator according to one embodiment of the present invention. This active anti-vibration device
As shown in the figure, a vibration isolation table 1 on which a precision instrument 3 is mounted,
A support mechanism 2 having a built-in pneumatic actuator for supporting the anti-vibration table 1 and applying a control force, and a plurality of vibration detecting means 4 such as an acceleration sensor for detecting the vibration of the anti-vibration table 1
A motion mode extracting means 5 for extracting a vibration signal of each motion mode such as translation and rotation of the vibration isolation table 1 based on an output signal of each vibration detecting means 4, and appropriately compensating an output of the motion mode extracting means 5 Compensation operation means 6, thrust distribution means 7 for distributing the compensation signal of each motion mode obtained by compensation operation means 6 as a drive signal of the pneumatic actuator of each support mechanism 2, and pressure of the pneumatic actuator of each support mechanism 2 Detecting means 8 for detecting vibrations, the vibration isolator 1 and the precision equipment 3 based on the pressure signal detected by the pressure detecting means 8.
Identification means 9 for estimating the position of the center of gravity of the combined body with

In the feedback loop constituting this device, the vibration of the vibration isolation table 1 is detected by each vibration detecting means 4, amplified by the amplifier 10, and
Is input to Then, from the vibration signal of only the necessary frequency band that has passed through the band-pass filter 11, the motion mode extracting means 5 extracts vibration information of each motion mode such as translation and rotation of the vibration isolation table 1. Exercise mode extraction means 5
Is determined by the position of the center of gravity of the vibration isolation table 1 and the arrangement of the vibration detecting means.

FIG. 2 shows the position of the center of gravity G of the vibration isolator 1 and the arrangement of the vibration detecting means 4 when the precision equipment 3 is located at a predetermined reference position. In this case, in the motion mode extracting means 5, the vibration signals a1, a
If the translation components ax and ay and the rotation component aθz in the X and Y directions of the vibration isolation table 1 are extracted based on 2 and a3, the motion mode extraction formula for extracting these is represented by Expression 1. .

[0020]

(Equation 1) The vibration information of each motion mode extracted by the motion mode extraction means 5 is processed by the compensation calculation means 6, and the compensation signal of each motion mode obtained by this processing is converted by the thrust distribution means 7 into the pneumatic actuator of each support mechanism 2. Is distributed to the drive signal. The distributed drive signals are applied to the pneumatic actuators of the support mechanisms 2 via the actuator drive circuit 12 to drive them.

In the thrust distributing means 7, a drive signal to the actuator of each support mechanism 2 is determined by a thrust distribution formula based on the position of the center of gravity of the vibration isolation table 1 and the arrangement of the pneumatic actuator of each support mechanism 2. FIG. 3 shows the position of the center of gravity G of the anti-vibration table 1 and the arrangement of the actuators of each support mechanism 2 when the precision equipment 3 is located at a predetermined reference position. In this case, the drive signal to each actuator is F1,
Assuming that the translational thrusts in the X and Y directions in the compensation signals of F2 and F3 and the respective motion modes are Fx and Fy, and the moment of the rotational component is Mz, the motion mode distribution formula (thrust distribution formula) is expressed by Formula 2. Is done.

[0022]

(Equation 2) On the other hand, as shown in FIG. 10, the pressure detecting means 8 is connected to a pipe connecting the air spring 14 and the servo valve 15 constituting the pneumatic actuator. 1 detects the pressure of the pneumatic actuator for maintaining the posture. The identification means 9 acquires the pressure detected by the pressure detection means 8 through the filter 13 for removing the influence of the reaction force generated when the mounted object moves, and based on the acquired information, the vibration isolation table 1 and the mounted The center of gravity of the combined object is estimated. The motion mode extraction formula and the thrust distribution formula when the stage, which is a load on the vibration isolation table 1, is at the reference position, are expressed by Formulas 1 and 2, and FIG.
As shown in FIGS. 5 and 5, when the stage 3 moves to an arbitrary position and the position of the center of gravity G of the combined body changes by α and β in the X and Y directions, the motion mode extraction formula and the thrust distribution formula are as follows. Equations 3 and 4 are used. Therefore, the identification means 9 sequentially changes the motion mode extraction formula and the thrust distribution formula based on Formulas 3 and 4.

[0023]

(Equation 3)

[0024]

(Equation 4) FIG. 11 shows an example of the effect when the vibration damping device of the present embodiment is used. When the change of the motion mode extraction formula and the thrust distribution formula by the identification means 9 is not performed, it takes time to attenuate the vibration as indicated by the thin line 16 in the figure, but the change of the motion mode extraction formula and the thrust distribution formula by the identification means 9 is performed. According to this embodiment in which the vibration is carried out in accordance with the movement of the load, the vibration can be rapidly attenuated as indicated by the thick line 17.

FIGS. 6 and 7 show the positional relationship between the designed position of the center of gravity G of the vibration isolator 1 and each vibration detecting means 4 in the active vibration isolator according to another embodiment of the present invention, and the vibration isolator. The positional relationship between the position of the center of gravity G and the actuator of each support mechanism 2 is shown. On the other hand, FIGS. 8 and 9 show actual accurate positional relations shifted from the positional relations of FIGS. 6 and 7 by α and β in the X and Y directions. Other points are the same as those in the embodiment of FIG.

In this case, the motion mode extraction formula and the thrust distribution formula in design are expressed by the above formulas 1 and 2, respectively.
The precise motion mode extraction equation and the thrust distribution equation are expressed by Equations 3 and 4, respectively. Then, the identification means 9 estimates the accurate center of gravity position of the vibration isolation table 1 using the pressure detected by the pressure detection means 8, and based on the estimation result, calculates the motion mode extraction formula and the thrust distribution formula respectively. It is appropriately changed according to 3 and Equation 4. The accurate estimation of the center of gravity position and the change of the motion mode extraction formula and the thrust distribution formula may be performed at any time, such as when the vibration isolator is started up.

The effect of this embodiment is also shown in FIG. That is, in the conventional case where the design is used as it is as the motion mode extraction formula and the thrust distribution formula, it takes time to attenuate the vibration as indicated by the thin line 16 in the figure. According to the present embodiment in which the expression is appropriately changed, the vibration can be rapidly attenuated as indicated by the thick line 17.

<Embodiment of Device Manufacturing Method> Next, an embodiment of a device manufacturing method using the above-described vibration isolator will be described. FIG. 13 shows a flow of manufacturing micro devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.). Step 1
In (Circuit Design), a device pattern is designed. Step 2 is a process for making a mask on the basis of the designed pattern. On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon or glass. Step 4 (wafer process) is called a pre-process,
An actual circuit is formed on the wafer by lithography using the prepared mask and wafer. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). including. In step 6 (inspection), inspections such as an operation check test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 14 shows a detailed flow of the wafer process (step 4). Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist processing), a resist is applied to the wafer. In step 16 (exposure), the exposure device aligns the circuit pattern of the mask on a plurality of shot areas of the wafer and performs printing exposure while supporting the anti-vibration while isolating the necessary parts of the exposure device using the anti-vibration device described above. Step 17 (development) develops the exposed wafer. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of this embodiment, a large-sized device, which has been conventionally difficult to manufacture, can be manufactured by exposing accurately.

[0031]

As described above, according to the present invention, sufficient vibration suppression performance can be obtained even when the center of gravity of the vibration isolation table or the combined body including the vibration isolation table and the mounted object moves. Also, even if the center of gravity of the vibration isolation table deviates from the design position,
Sufficient vibration suppression performance can be obtained. Therefore, a more accurate device can be manufactured.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an active vibration isolation device according to an embodiment of the present invention.

FIG. 2 is a layout diagram of a sensor for detecting vibration of a vibration isolation table in the apparatus of FIG.

3 is an arrangement diagram of an actuator for applying a control force to a vibration isolation table in the apparatus of FIG.

FIG. 4 is an arrangement diagram of sensors for detecting vibration of the vibration isolation table when the center of gravity moves in the apparatus of FIG. 1;

FIG. 5 is a layout view of an actuator that applies a control force to the vibration isolation table when the center of gravity moves in the apparatus of FIG.

FIG. 6 is a diagram showing a positional relationship between a designed center of gravity of an anti-vibration table and each vibration detecting means in an active anti-vibration apparatus according to another embodiment of the present invention.

FIG. 7 is a diagram showing a positional relationship between a designed center of gravity of the vibration isolation table and an actuator of each support mechanism in the active vibration isolation device of FIG. 6;

8 is a diagram showing an actual accurate positional relationship shifted from the positional relationship of FIG. 6 by α and β in the X and Y directions.

9 is a diagram showing an actual accurate positional relationship shifted from the positional relationship of FIG. 7 by α and β in the X and Y directions.

FIG. 10 is a structural view of a pneumatic actuator in the apparatus of FIG.

FIG. 11 is a graph showing the effect of the vibration damping device according to the present invention.

FIG. 12 is a block diagram illustrating a configuration of a conventional vibration isolation device.

FIG. 13 is a flowchart illustrating a device manufacturing method that can use the vibration damping apparatus or method of the present invention.

FIG. 14 is a detailed flowchart of a wafer process in FIG.

[Explanation of symbols]

1: vibration isolation table 2: support mechanism for vibration isolation table 1, 3: mounted object such as XY stage, 4: vibration detection means, 5: motion mode extraction means, 6: compensation calculation means, 7: thrust distribution means, 8: Pressure detection means, 9: Identification means, 10: Amplifier, 11: Bandpass filter, 12: Actuator drive circuit, 13:
Low-pass filter, 14: air spring, 15: servo valve.

Claims (4)

[Claims] 1. A vibration isolation table on which an object to be subjected to vibration isolation is mounted, a plurality of support mechanisms having an actuator for supporting the vibration isolation table with vibration isolation and applying a control force to the vibration isolation table, and the vibration isolation table A plurality of vibration detecting means for detecting a vibration of the vibration detecting means; an extracting means for extracting a vibration signal of a predetermined motion mode of the vibration isolation table based on an output signal of the plurality of vibration detecting means; And a distribution unit that distributes the compensation signal of each motion mode obtained by the compensation operation unit as a drive signal of each actuator, wherein the vibration isolation table or the vibration isolation table and an object are provided. An active vibration isolator, wherein the calculation method of the extraction means and the distribution means is changed based on the position of the center of gravity of the structure to which is added. 2. The method according to claim 1, wherein the actuator is a pneumatic actuator, and the position of the center of gravity is determined based on a pressure of the pneumatic actuator required to maintain a predetermined posture of the vibration isolation table by the pneumatic actuator. The active vibration isolator according to claim 1, wherein 3. A step of detecting vibrations at a plurality of positions of the vibration isolation table, a step of extracting a vibration signal of a predetermined motion mode of the vibration isolation table based on the detection result, and Applying a predetermined compensation to the vibration signal, and providing the compensated vibration signal of each motion mode to a plurality of actuators that support the vibration isolation table and apply a control force to the vibration isolation table. And a calculation method for extracting and distributing the vibration signal of the motion mode based on the position of the center of gravity of the vibration isolation table or a structure in which the vibration isolation table and the vibration isolation target are combined together And a step of changing the temperature. 4. A step of supporting the substrate stage, the projection optical system, or the original plate stage of the exposure apparatus in a vibration-proof manner by the active vibration isolation method according to claim 3, and the pattern of the original plate on the original plate stage by the exposure apparatus. Exposing the substrate on the substrate stage via the projection optical system.