Vibration isolator and exposure apparatus

What is claimed is:

1. A vibration isolator which reduces vibrations and inclination generated by a moving body stage, the vibration isolator comprising:

at least three vibration isolating pads;

a vibration isolating stand support held in a substantially horizontal position by the vibration isolating pads;

actuators capable of driving the vibration isolating stand, each of said actuators having a movable member and a stator;

displacement sensors capable of detecting displacement of the vibration isolating stand;

vibration sensors capable of detecting vibration of the vibration isolating stand, said vibration sensors being fixed to the vibration isolating stand;

a control mode unit of the vibration isolating stand capable of selecting a control mode for the vibration isolating stand from a plurality of control modes in which an error tolerance in a control is changed based on an operating mode of the moving body stage; and

a first control system, connected to said control mode unit, capable of controlling the actuators based on outputs of the displacement sensors and the vibration sensors in accordance with the selected control mode.

2. The vibration isolator according to claim 1, wherein the control mode unit is capable of operating in a first mode of operation wherein only ranges of target setting values can be altered.

3. The vibration isolator according to claim 2, wherein the control mode is capable of operating in a second mode of operation wherein the target setting values and the ranges of the target setting values are capable of being altered.

4. The vibration isolator according to claim 3, wherein at least three actuators drive the vibration isolating stand in a vertical direction.

5. The vibration isolator according to claim 4, wherein the vibration isolator further includes a second control system that corrects at least a portion of an inclination of the vibration isolating stand occurring as a result of the movement of a moving body stage of an exposure projection apparatus, based on outputs of the displacement sensors.

6. The vibration isolator according to claim 5, wherein the second control system further includes air pressure control circuits that control a flow rate of air supplied to the vibration isolating pads to correct the inclination of the vibration isolating stand, by driving air pressure control circuits based on the outputs of the displacement sensors.

7. The vibration isolator according to claim 6, wherein in the second mode of operation a setting means predicts the amount of inclination of the vibration isolating stand in accordance with movement command values of the moving body stage of an exposure projection apparatus by calculating an amount of inclination of the vibration isolating stand based on a movement position of the moving body stage of the exposure projection apparatus and spring constants of the isolating pads, and sets the target setting values so that the amount of inclination of the vibration isolating stand coincides with the results of the prediction.

8. The vibration isolator according to claim 4, wherein the second mode of operation a setting means predicts an inclination of the vibration isolating stand in accordance with movement command values of the moving body stage of the exposure projection apparatus by calculating the inclination of the vibration isolating stand based on a movement position of the moving body stage of the exposure projection apparatus and spring constants of the isolating pads, and sets the target setting values so that the amount of inclination of the vibration isolating stand coincides with the results of the prediction.

9. The vibration isolator according to claim 3, wherein the second mode of operation, the setting means predicts an inclination of the vibration isolating stand in accordance with movement command values of the moving body stage of the exposure projection apparatus by calculating the amount of inclination of the vibration isolating stand based on a movement position of the moving body stage of an exposure projection apparatus and spring constants of the isolating pads, and sets the target setting values so that the amount of inclination of the vibration isolating stand coincides with the results of the prediction.

10. The vibration isolator according to claim 2, wherein at least three actuators drive the vibration isolating stand in the vertical direction.

11. The vibration isolator according to claim 10, wherein the vibration isolator further includes a second control system that corrects at least a portion of an inclination of the isolating stand occurring as a result of the movement of the moving body stage of the exposure projection apparatus, based on outputs of the displacement sensors.

12. The vibration isolator according to claim 11, wherein the second control system further includes air pressure control circuits that control a flow rate of air supplied to the vibration isolating pads to correct the inclination of the vibration isolating stand by driving air pressure control circuits based on the outputs of the displacement sensors.

13. The vibration isolator according to claim 2, wherein the vibration isolator further includes a second control system that corrects at least a portion of an inclination of the vibration isolating stand occurring as a result of the movement of the moving body stage of the exposure projection apparatus, based on outputs of the displacement sensors.

14. The vibration isolator according to claim 13, wherein the second control system further includes:

air pressure control circuits that control a flow rate of air supplied to the vibration isolating pads to correct the inclination of the isolating stand, by driving the air pressure control circuits based on the outputs of the displacement sensors.

15. The vibration isolator according to claim 1, wherein the control mode unit is capable of operating in a mode of operation wherein target setting values and ranges of target setting values are capable of being altered.

16. The vibration isolator according to claim 15, wherein at least three actuators drive the vibration isolating stand in the vertical direction.

17. The vibration isolator according to claim 16, wherein the vibration isolator further includes:

a second control system which corrects at least a portion of the inclination of the isolating stand, occurring as a result of the movement of a moving body stage of an exposure projection apparatus, based on outputs of the displacement sensors.

18. The vibration isolator according to claim 17, wherein the second control system further includes air pressure control circuits that control a flow rate of air supplied to the vibration isolating pads to correct the inclination of the vibration isolating stand by driving air pressure control circuits based on the outputs of displacement sensors.

19. The vibration isolator according to claim 18, wherein in a second operating mode, the setting means predicts the inclination of the vibration isolating stand in accordance with movement command values of a moving body stage of an exposure projection apparatus by calculating the amount of inclination of the vibration isolating stand based on a movement position of a moving body stage of an exposure projection apparatus and spring constants of the isolating pads, and sets the target setting values so that the amount of inclination of the vibration isolating stand coincides with the results of the prediction.

20. The vibration isolator according to claim 17, wherein in a second operating mode, the setting means predicts an inclination of the vibration isolating stand in accordance with movement command values of a moving body stage of an exposure projection apparatus by calculating the amount of inclination of the vibration isolating stand based on a movement position of a moving body stage of an exposure projection apparatus and spring constants of the isolating pads, and sets the target setting values so that the amount of inclination of the vibration isolating stand coincides with the results of the prediction.

21. The vibration isolator according to claim 16, wherein in a second operating mode, the setting means predicts an inclination of the vibration isolating stand in accordance with movement command values of a moving body stage of an exposure projection apparatus by calculating the inclination of the vibration isolating stand based on a movement position of a moving body stage of an exposure projection apparatus and spring constants of the isolating pads, and sets the target setting values so that the amount of inclination of the vibration isolating stand coincides with the results of the prediction.

22. The vibration isolator according to claim 15, wherein in a second operating mode, the setting means predicts the inclination of the vibration isolating stand in accordance with movement command values of a moving body stage of an exposure projection apparatus by calculating the inclination of the vibration isolating stand based on a movement position of a moving body stage of an exposure projection apparatus and spring constants of the isolating pads, and sets the target setting values so that the amount of inclination of the vibration isolating stand coincides with the results of the prediction.

23. The vibration isolator according to claim 1, wherein at least three actuators drive the vibration isolating stand in the vertical direction.

24. The vibration isolator according to claim 23, wherein the vibration isolator further includes a second control system that corrects at least a portion of an inclination of the isolating stand occurring as a result of the movement of a moving body stage of an exposure projection apparatus, based on outputs of the displacement sensors.

25. The vibration isolator according to claim 24, wherein the second control system further includes air pressure control circuits that control a flow rate of air supplied to the vibration isolating pads to correct the inclination of the vibration isolating stand, by driving the air pressure control circuits based on outputs of displacement sensors.

26. An exposure apparatus which transfers an image of a pattern formed on a mask on a photosensitive substrate by an illuminating light, the exposure apparatus comprising:

a projection device which has projection system to project the image on the substrate;

at least three vibration isolating pads;

a vibration isolating stand support held in a substantially horizontal position by the vibration isolating pads;

a substrate stage which holds the substrate, said substrate stage movably supported by said vibration isolating stand;

actuators capable of driving the vibration isolating stand, each of said actuators having a movable member and a stator;

displacement sensors capable of detecting the displacement of the vibration isolating stand;

vibration sensors capable of detecting vibration of the vibration isolating stand, said vibration sensors being fixed to the vibration isolating stand;

a control mode unit of the vibration isolating stand capable of selecting a control mode for the vibration isolating stand from a plurality of control modes in which an error tolerance in a control is changed based on an operating mode of said substrate stage; and

a control device, connected to said control mode unit, capable of controlling the actuators based on outputs of the displacement sensors and the vibration sensors in accordance with the selected control mode.

27. The exposure apparatus according to claim 26, wherein at least three actuators drive the vibration isolating stand in the vertical direction.

28. The exposure apparatus according to claim 27, wherein the exposure apparatus further includes a second control device that corrects at least a portion of an inclination of the vibration isolating stand occurring as a result of the movement of a moving body stage of the exposure projection apparatus, based on outputs of the displacement sensors.

29. The exposure apparatus according to claim 28, wherein the second control device further includes air pressure control circuits that control a flow rate of air supplied to the vibration isolating pads to correct the inclination of the vibration isolating stand, by driving the air pressure control circuits based on outputs of the displacement sensors.

30. The exposure apparatus according to claim 29, wherein the exposure apparatus further includes a detector capable of detecting marks formed on the photosensitive substrate.

31. The exposure apparatus according to claim 30, wherein the control mode unit includes a first mode of operation wherein an exposure of the photosensitive substrate is performed after the substrate stage is moved so that the photosensitive substrate is positioned in a prescribed exposure position.

32. The exposure apparatus according to claim 31, wherein the control mode unit further includes a second mode of operation wherein the substrate stage is moved and marks are detected by a detector.

33. The exposure apparatus according to claim 32, wherein the operating mode unit further includes a third mode of operation wherein the substrate stage is moved to a prescribed receiving position in order to receive a photosensitive substrate.

34. The exposure apparatus according to claim 26, wherein the control mode unit includes a first mode of operation wherein an exposure of a photosensitive substrate is performed after the substrate stage is moved so that a photosensitive substrate is positioned in a prescribed exposure position.

35. The exposure apparatus according to claim 34, wherein the control mode unit further includes a second mode of operation wherein the substrate stage is moved and marks are detected by the detector.

36. The exposure apparatus according to claim 35, the operating mode unit further includes a third mode of operation wherein the substrate stage is moved to a prescribed receiving position in order to receive the photosensitive substrate.

37. The exposure apparatus according to claim 26, the operating mode unit includes a first mode of operation wherein the substrate stage is moved to a prescribed receiving position in order to receive the photosensitive substrate.

38. A stage apparatus, comprising:

a stage movable while holding an object;

a support member that supports the stage so as to be movable;

a driving device that drives the support member, at least a portion of the driving device being installed on the support member; and

a controlling device connected to the driving device, the controlling device being capable of controlling the driving device by a plurality of controlling methods in which an error tolerance in a control is changed, the controlling device controlling the driving device by a selected controlling method.

39. The stage apparatus according to claim 38, wherein the plurality of controlling methods in the controlling device includes a controlling mode in which the controlling device does not control the driving device.

40. The stage apparatus according to claim 38, wherein the controlling device controls the driving device so as to reduce vibration conducted to the support member.

41. The stage apparatus according to claim 40, wherein the vibration conducted to the support member is caused by the movement of the stage.

42. The stage apparatus according to claim 38, wherein the controlling device controls the driving device so as to correct changes in attitude of the stage apparatus due to the movement of the stage.

43. The stage apparatus according to claim 38, further comprising a vibration detector that detects vibration conducted to the support member.

44. The stage apparatus according to claim 43, wherein the vibration detector is an acceleration sensor.

45. The stage apparatus according to claim 43, wherein the vibration detector is a displacement sensor.

46. The stage apparatus according to claim 38, further comprising:

a displacement sensor that detects changes in attitude of the stage apparatus.

47. An exposure apparatus for exposing a mask pattern on a mask onto a substrate, comprising:

an exposure main body that exposes the mask pattern onto the substrate, the exposure main body including a mask stage movable while holding the mask and a substrate stage movable while holding the substrate;

a driving device connected to the exposure main body, the driving device driving a mechanical part of the exposure main body that is different from the mask stage and the substrate stage; and

a controlling device connected to the driving device, the controlling device being capable of controlling the driving device by a plurality of controlling methods in which an error tolerance in a control is changed, the controlling device controlling the driving device by a selected controlling method.

48. The exposure apparatus according to claim 47, wherein the exposure main body includes a first support part that supports the substrate stage to be movable and a second support part that supports the mask stage to be movable.

49. The exposure apparatus according to claim 48, wherein the driving device drives the first support part.

50. The exposure apparatus according to claim 48, wherein the first support part and the second support part are mechanically connected.

51. The exposure apparatus according to claim 49, wherein the driving device drives the first support part and the second support part.

52. The exposure apparatus according to claim 48, wherein the exposure main body includes a projection system installed between the mask stage and the substrate stage, the projection system projecting the mask pattern onto the substrate.

53. The exposure apparatus according to claim 52, wherein the projection system optically projects the mask pattern onto the substrate.

54. The exposure apparatus according to claim 52, wherein the projection system and the second support part are mechanically connected.

55. The exposure apparatus according to claim 47, wherein the plurality of controlling methods in the controlling device includes a controlling mode in which the controlling device does not control the driving device.

56. The exposure apparatus according to claim 47, wherein the controlling device controls the driving device so as to reduce vibration conducted to the exposure main body.

57. The exposure apparatus according to claim 47 , wherein the exposure apparatus is a scanning type exposure apparatus in which the mask pattern is exposed onto the substrate while the mask stage and the substrate stage are moved.

58. A substrate exposed with the mask pattern by the exposure apparatus of claim 47.

59. A method for exposing a mask pattern on a mask onto a substrate in an exposure apparatus, the method comprising the steps of:

providing an exposure apparatus main body, the exposure apparatus main body including a mask stage movable while holding the mask and a substrate stage movable while holding the substrate, the exposure apparatus main body exposing the mask pattern onto the substrate;

providing a drive device connected to the exposure apparatus main body, the drive device driving a mechanical part of the exposure apparatus main body that is different from the mask stage and the substrate stage; and

providing a controller connected to the drive device, the controller being capable of controlling the drive device by a plurality of controlling methods in which an error tolerance in a control is changed, the controller controlling the drive device by a selected controlling method.

60. The method according to claim 59, wherein the exposure apparatus main body includes a first support part that supports the substrate stage to be movable and second support part that supports the mask stage to be movable.

61. The method according to claim 60, wherein the first support part and second support part are mechanically connected.

62. The method according to claim 60, wherein the drive device drives the first support part and the second support part.

63. The method according to claim 60, wherein the exposure apparatus main body includes a projection system disposed between the mask stage and the substrate stage, the projection system projecting the mask pattern onto the substrate.

64. The method according to claim 63, wherein the projection system optically projects the mask pattern onto the substrate.

65. The method according to claim 63, wherein the projection system and the second support part are mechanically connected.

66. The method according to claim 59, wherein the exposure apparatus is a scanning type exposure apparatus that exposes the mask pattern onto the substrate while the mask stage and the substrate stage are moved.

Description Submit all comments and votes

This application claims the benefit of Japanese Application No. 8-283187, filed on Oct. 4, 1996, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vibration isolator and a vibration isolator in combination with an exposure apparatus. More specifically the present invention relates to a so-called "active type" vibration isolator in which a vibration isolating stand is driven by actuators so that the vibration of the vibration isolating stand is canceled, and also an exposure apparatus that is equipped with the vibration isolator.

2. Discussion of the Related Art

As precision requirements have increased in high-precision instruments, such as step-and-repeat-type reducing projection exposure devices (so-called "steppers"), it has become necessary to isolate micro-vibrations acting on the base plate (vibration isolating stand) of such devices from the installation floor at the micro-G level. Various types of dampers, such as mechanical dampers, in which compression coil springs are placed in a damping liquid and pneumatic dampers, have been used as vibration isolating pads that support the vibration isolating stand. The vibration isolating pads also are capable of performing some centering functions, especially in air spring vibration isolators equipped with pneumatic dampers, wherein the spring constant can be set at a small value so that vibrations exceeding approximately 10 Hz or higher can be isolated. Accordingly, such vibration isolators are widely used for the support of precision instruments. Recently, active vibration isolators have been proposed in order to break through the limits inherent in passive vibration isolators. The active vibration isolators are vibration isolators in which the vibration of the vibration isolating stand is detected by sensors and vibration control is accomplished by driving actuators on the basis of the output of the sensors. Such vibration isolators are capable of producing an ideal vibration isolating effect with no resonance peak in the low-frequency control region.

In steppers, an XY-stage (wafer stage), which undergoes a large acceleration and deceleration, is mounted on a base plate held by vibration isolating pads. The center of gravity of the main body of the exposure apparatus moves simultaneously with the movement of the XY-stage. In an active type vibration isolator, when the position of the center of gravity of the main body changes as a result of the movement of the wafer stage, the initial positioning is performed by means of a position control loop. If the amount of movement of the stage is large, the corresponding change in the position of the center of gravity of the main body also is large, so that the main body experiences tilting. The amount of this inclination increases with an increase in the amount of change in the position of the center of gravity of the main body, so that the driving force required in the actuators in order to correct this is also increased. In active vibration isolators used in conventional exposure apparatus, the output values of the respective displacement sensors obtained when the respective stages, i.e., wafer X-stage, wafer Y-stage, and in scan-type exposure apparatus, the reticle stage; used for the target setting values, are used in order to correct the inclination of the base plate (vibration isolating stand) and limit vibration. Furthermore, the target setting ranges are uniformly set on the basis of permissible values with six degrees of freedom at the emission position of the light exposure source and the receiving positions of the reticle and wafer loader.

The amount of heat generated by the actuators in the vibration isolator is especially large when the main body is tilted, so that the environment in which the exposure apparatus is placed undergoes a large temperature variation. This temperature variation in the environment has an effect on the measurement precision of the laser interferometers that measure the position of the XY-stage. The temperature variation therefore leads to a deterioration in the stage positioning precision.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a vibration isolator and exposure apparatus that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a vibration isolator that allows efficient actuator control operation and prevents the unnecessary generation of heat by the actuators.

Another object of the present invention is to provide a reduction in the generation of heat by the actuators.

A further object of the present invention is to provide a superior exposure apparatus employing a vibration isolator in which an efficient actuator control operation is performed in accordance with the operating mode of the substrate stage, so that changes in the ambient temperature caused by the unnecessary generation of heat by the actuators can be suppressed.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the vibration isolator and exposure apparatus includes a vibration isolating stand that is held in a substantially horizontal position via at least three vibration isolating pads, a moving body that moves across the vibration isolating stand, a plurality of actuators that drive the vibration isolating stand, displacement sensors that detect the displacement of the vibration isolating stand, vibration sensors that detect the vibration of the vibration isolating stand, a setting means that sets the control mode of the vibration isolating stand in accordance with the operating mode of the moving body, and a first control system that controls the plurality of actuators on the basis of the outputs of the displacement sensors and vibration sensors in accordance with the control mode.

The control mode of the vibration isolating stand is set by the setting means in accordance with the operating mode of the moving body. The first control system performs vibration control and position control of the vibration isolating stand by controlling the plurality of actuators on the basis of the outputs of the displacement sensors and vibration sensors in accordance with the set control mode of the vibration isolating stand.

The "operating mode" of the moving body refers to a mode that is suited to the object of the operation of the moving body. For example, in cases where the moving body is to be positioned in a prescribed position, the amount of positioning error that is allowed in judging this positioning to be set and the length of time for which the set state must be maintained, vary according to the object of the operation of the moving body, so that the positioning error is influenced by the target values and permissible error ranges of the vibration control, position control, and attitude control of the vibration isolating stand.

The "control mode" of the vibration isolating stand refers to the mode used to control the vibration of the vibration isolating stand. This is set in accordance with the operating mode of the moving body that moves across the surface of the vibration isolating stand. Consideration is given to the fact that more efficient vibration control of the vibration isolating stand and control of the actuators is possible if the target values and permissible error ranges in the directions of the respective degrees of freedom, in cases where the vibration of the vibration isolating stand is controlled with multiple degrees of freedom, are set at different values.

Accordingly, the present invention allows efficient control of the actuators in accordance with the operating mode of the moving body as compared to cases where the target setting values and target setting ranges of vibration control and position control of the vibration isolating stand are uniformly set as in a conventional method. Furthermore, the setting time of the positioning can also be adjusted to a suitable time for the operating mode. Moreover, in cases where the permissible vibration error is large, in accordance with the operating mode, the apparatus is set in a control mode such that the target setting ranges are broad. Accordingly, unnecessary driving of the actuators can be avoided so that unnecessary generation of heat by the actuators can be prevented.

Any desired modes may be set as the operating modes of the moving body, as long as these modes can be set under conditions such as those described above. For example, the operating modes of the moving body may include a first mode in which only the target setting ranges, of the target setting values, and setting ranges can be altered and a second mode in which both the target setting values and setting ranges can be altered. Prescribed characteristic values, e. g., values such that the target setting values in the directions of all of a multiple number of degrees of freedom are zero, may be set as the target setting values in the first mode.

In another aspect, the vibration isolator includes actuators that drive the vibration isolating stand in the vertical direction at different places. The vibration isolator further has a second control system that has air pressure control circuits that control the flow rate of air supplied to the vibration isolating pads, and which corrects at least a portion of the inclination of the isolating stand occurring as a result of the movement of the moving body by driving the air pressure control circuits on the basis of the outputs of the displacement sensors.

Thus, in addition to an efficient control operation suited to the operating mode of the moving body being ensured by the setting of the control mode, the air pressure control circuits are driven by the second control system on the basis of the outputs of the displacement sensors where the vibration isolating stand is tilted as a result of the movement of the moving body. Thus, all or part of the inclination of the vibration isolating stand caused by the movement of the moving body is corrected. Accordingly, even if the operating mode of the moving body is in the first mode and the characteristic values are set at their target setting values, the amount of correction performed by the actuators for driving the vibration isolating stand in the vertical direction that is required in order to return the vibration isolating stand to its original attitude can be greatly reduced. By reducing the amount of correction required, unnecessary generation of heat by the actuators can be prevented.

Additionally, the vibration isolation or apparatus may be designed so that if the operating mode of the moving body is the second operating mode, the setting means predicts the amount of inclination of the vibration isolating stand. The production is based on the movement command values of the moving body obtained by calculating the amount of inclination of the vibration isolating stand on the basis of the movement position of the moving body and the spring constants of the isolating pads. The target setting values are then set so that the amount of inclination of the vibration isolating stand coincides with the results of the prediction. The amount of inclination is predicted according to the movement command values of the moving body prior to the actual initiation of movement by the moving body. The target setting values (relating to the inclination of the vibration isolating stand) are set so that the amount of inclination of the vibration isolating stand agrees with the results of the prediction. There is no need for the first control system to drive the actuators for the purpose of attitude control (mainly inclination control) of the vibration isolating stand when the moving body moves to the position corresponding to the movement command values because driving of the actuators for the purpose of vibration control alone is sufficient. Accordingly, the amount of driving of the actuators can be conspicuously reduced, so that the amount of heat generated is further suppressed.

In a further aspect of the present invention, exposure apparatus exposes the image of a pattern formed in a mask R on a photosensitive substrate W via an optical projection system PL while causing the stepwise movement of a substrate stage, which holds the photosensitive substrate W. The exposure apparatus includes a vibration isolating stand that is held in a substantially horizontal position via at least three vibration isolating pads, at least one moving stage that includes the substrate stage that moves across the vibration isolating stand, a plurality of actuators that drive the vibration isolating stand, displacement sensors that detect the displacement of the vibration isolating stand, vibration sensors that detect the vibration of the vibration isolating stand, a setting means that sets the control mode of the vibration isolating stand in accordance with an apparatus operating mode relating to the movement of the substrate stage, and a control device that controls the plurality of actuators on the basis of the outputs of the displacement sensors and vibration sensors in accordance with the control mode.

The term "apparatus operating mode relating to the movement of the substrate stage" refers to various operating modes of the exposure apparatus in which the movement conditions (object of movement) of the substrate stage are different. This term is defined in the same sense as "operating mode of the moving body."

Additionally, as described in the previous aspects at the present invention, the control mode of the vibration isolating stand is set in accordance with the operating mode of the substrate stage that moves across the surface of the vibration isolating stand, with consideration being given to the fact that more efficient vibration control of the vibration isolating stand (control of the actuators) is possible if the target values and permissible error ranges in the directions of the respective degrees of freedom (in cases where the vibration of the vibration isolating stand is controlled with multiple degrees of freedom) are set at different values.

Accordingly, the present invention allows efficient control of the actuators in accordance with the operating mode of the substrate stage (as compared to the conventional method wherein the target setting values and target setting ranges of vibration control and position control of the vibration isolating stand are uniformly set). The setting time of the positioning can also be adjusted to a time that is suited to the operating mode. Where the permissible vibration error is large (in accordance with the operating mode), the apparatus is set in a control mode that is such that the target setting ranges are broad, thereby avoiding unnecessary driving of the actuators, so that temperature changes in the environment, which have an effect on the exposure precision can be suppressed.

The exposure apparatus of the present invention may be either a stationary exposure-type apparatus, such as a reduction projection-type exposure apparatus using a step-and-repeat system (i.e., a so-called "stepper"), or a scan exposure-type exposure apparatus, such as a step-and-scan type-exposure apparatus, as long as the exposure apparatus performs an exposure while causing the stepwise movement of a substrate stage holding a photosensitive substrate.

Various types of modes are conceivable as the operating modes. For example, where the apparatus has a detection means that detects marks formed on the photosensitive substrate W, the apparatus operating modes may include a first mode in which the exposure is performed after the stage is moved so that the photosensitive substrate W is positioned in a prescribed exposure position, and a second mode in which the substrate stage is moved and the alignment marks are detected by the detection means. Where, for example, the exposure light source is installed in a position separate from the vibration isolating stand and the detection means is installed on the vibration isolating stand, vibration control and attitude control of the vibration isolating stand must be performed with strict precision in the first mode.

Furthermore, the target values for vibration control and position control of the vibration isolating stand must be fixed (i.e., the target setting values in the directions of all degrees of freedom must be set at zero). In the second mode, on the other hand, the attitude control of the vibration isolating stand need not be performed with a very high precision. It is necessary to vary the target setting values in accordance with the movement position of the substrate stage. Thus, the control modes are set with consideration given to the parameters, so that efficient actuator control can be accomplished.

The apparatus operating modes may also include a third mode in which the substrate stage is moved to a prescribed receiving position in order to receive the photosensitive substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a perspective view that illustrates an exposure apparatus of the first embodiment of the present invention;

FIG. 2 is an exploded schematic structural diagram illustrating the respective constituent parts of the exposure apparatus, as shown in FIG. 1, except for the base plate, first and second columns;

FIG. 3 is a schematic perspective view that illustrates the system used for the driving control of the vibration isolating pads of the present invention;

FIG. 4 is a diagram that illustrates the scanning exposure process of the apparatus of FIG. 1 of the present invention;

FIG. 5 is a control block diagram illustrating the circuits of the control system used for the actuators and vibration isolating pad of the present invention;

FIG. 6 illustrates an example of the circuitry of the air pressure control circuits used to control the respective flow rates of the air supplied to the vibration isolating pads of the present invention;

FIGS. 7(A), 7(B), and 7(C) illustrate alternate methods for the connection of the air pressure control circuits to the vibration isolating pads of the present invention; and

FIG. 8 illustrates one example of the arrangement of the vibration isolating pads.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

The first embodiment of the present invention will now be described with reference to FIGS. 1 through 8.

FIG. 1 illustrates a schematic perspective view of a step-and-scan-type exposure apparatus 100 of the first embodiment of the present invention. FIG. 2 is an exploded schematic structural diagram that illustrates the respective parts of the exposure apparatus 100, except for the base plate, first and second columns, which will be described later.

In FIG. 1, a rectangular plate-shaped pedestal 2 is installed on a floor that constitutes the installation surface for the apparatus. Vibration isolating pads 4A through 4D (the vibration isolating pad 4D is shown in FIG. 3) are installed on the pedestal 2. A rectangular base plate 6 is installed as a vibration isolating stand on the vibration isolating pads 4A through 4D. An optical projection system PL is used in the exposure apparatus 100 of the first embodiment (which will be described later), the Z-axis is taken parallel to the optical-axis of the optical projection system PL, the X-axis is taken in the direction of the length of the base plate 6 in the plane perpendicular to the Z-axis, and the Y-axis is taken in the direction perpendicular to Z-axis. Furthermore, the directions of rotation about the respective axes are defined as the Z.theta., Y.theta., and X.theta.-directions. As is necessary in the following description, the directions indicated by the arrows indicating the X-, Y-, and Z-axes in FIG. 1 will be referred to as the +X, +Y, and +Z-directions, while the opposite directions will be distinguished from the directions as the -X, -Y, and -Z-directions.

The vibration isolating pads 4A through 4D are respectively positioned in the vicinities of the four vertices of the rectangular bottom surface of the base plate 6. In the present working configuration, pneumatic dampers are used as the vibration isolating pads 4A through 4D. As shown in FIG. 3, the