Support mechanism, optical system, exposure device, and article manufacturing method

Abstract

To provide an advantageous technique to prevent variations in the position of an article to be supported.SOLUTION: A support mechanism comprises: a first support member that supports an object; a second support member that supports the first support member with a first elastic member therebetween; a feed screw that is arranged to apply force to the first support member; a worm gear that includes a worm wheel connected with the feed screw and a worm screwed into the worm wheel; and a second elastic member that applies holding force to the worm wheel through the worm so as to cancel at least part of torque of restoring force of the first elastic member received by the feed screw, and thereby holds the position of the feed screw.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a support mechanism, an optical system, an exposure apparatus, and an article manufacturing method. [Background technology]

[0002] An exposure apparatus used in a lithography process for manufacturing articles such as microdevices, such as semiconductor devices, is an apparatus that transfers a fine pattern of an original onto a substrate. In order to transfer a fine pattern onto a substrate accurately, it is important to reduce the aberration of the projection optical system of the exposure apparatus. The aberration of the projection optical system depends on the refractive index and surface shape of the multiple optical elements that constitute the projection optical system, and in the assembly stage of the projection optical system, it is required to assemble the positions of the multiple optical elements accurately. After the projection optical system is assembled, the performance of the projection optical system is measured, and the positions of the optical elements can be adjusted based on the measurement results. After the projection optical system is assembled, the positions of all or part of the multiple optical elements can be adjusted to correct fluctuations caused by external disturbances such as shocks to which the projection optical system is subjected during transportation, temperature changes in the exposure apparatus, and vibrations.

[0003] Patent Document 1 describes a support mechanism for an optical element that includes multiple elastic members that elastically deform and a pressing member (e.g., a micrometer) that applies force to the elastic members. The support mechanism adjusts the position of the optical element by the pressing member applying force to the elastic members. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3805323 Summary of the Invention [Problem to be solved by the invention]

[0005] In a support mechanism capable of adjusting the position of a supported object such as an optical element by a pressing member such as a micrometer, the position of the object can fluctuate due to disturbances such as impact, temperature change, and vibration.

[0006] An object of the present invention is to provide an advantageous technique for suppressing fluctuations in the position of an object to be supported. [Means for solving the problem]

[0007] One aspect of the present invention relates to a support mechanism comprising: a first support member that supports an object; a second support member that supports the first support member via a first elastic member; a feed screw arranged to apply force to the first support member; a worm gear including a worm wheel connected to the feed screw and a worm screwed into the worm wheel; and a second elastic member that applies a holding force to the worm wheel via the worm so as to offset at least a portion of the torque that the feed screw receives due to the restoring force of the first elastic member, thereby maintaining the position of the feed screw. Effect of the Invention

[0008] The present invention provides an advantageous technique for suppressing fluctuations in the position of an object to be supported. [Brief description of the drawings]

[0009] [Figure 1A] FIG. 2 is a schematic perspective view showing the configuration of a support mechanism according to the first embodiment. [Figure 1B] 1B is a cross-sectional view of the support mechanism of FIG. 1A taken along line AA. [Figure 1C] 1B is a cross-sectional view of the support mechanism of FIG. 1A taken along line BB. [Figure 2A] FIG. 2 is a schematic perspective view showing a configuration of a support mechanism in a first configuration example of the first embodiment. [Figure 2B] 2B is a cross-sectional view of the support mechanism of FIG. 2A taken along line AA. [Diagram 3] 5 is a schematic perspective view showing the configuration of a support mechanism 50 in a second configuration example of the first embodiment. FIG. [Figure 4] FIG. 13 is a schematic perspective view showing the configuration of a support mechanism in a third configuration example of the first embodiment. [Diagram 5] FIG. 13 is a schematic perspective view showing the configuration of a support mechanism in a fourth configuration example of the first embodiment. [Figure 6A] FIG. 13 is a schematic perspective view showing the configuration of a support mechanism according to a second embodiment. [Figure 6B] 6B is a cross-sectional view of the support mechanism of FIG. 6A taken along line AA. [Figure 7] FIG. 13 is a schematic perspective view showing the configuration of a support mechanism according to a third embodiment. [Figure 8] 6A to 6C are diagrams illustrating a function provided by a second elastic member. [Figure 9] 6A to 6C are diagrams illustrating a function provided by a second elastic member. [Figure 10] FIG. 13 is a diagram showing the configuration of an exposure apparatus according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] FIG. 1A is a schematic perspective view showing a configuration of a support mechanism 50 of a first embodiment. FIG. 1B is a cross-sectional view of the support mechanism 50 of FIG. 1A taken along line AA. FIG. 1C is a cross-sectional view of the support mechanism 50 of FIG. 1A taken along line BB. The support mechanism 50 is configured to support an object OP. The object OP may have, for example, a circular shape. The object OP may be, for example, an optical element.

[0012] The support mechanism 50 may include a first support member 12 that supports an object OP, a second support member 11 that supports the first support member 12 via a first elastic member 13, a feed screw 2 arranged to apply a force to the first support member 12, and a worm gear 3. In the first embodiment, the first elastic member 13 is connected to a first point PA of the first support member 12, and the feed screw 2 is configured to apply a pressing force to a second point PB different from the first point PA of the first support member 12. In one example, the object OP has a circular shape, the first support member 12 has a ring shape that surrounds the side surface (cylindrical surface) of the object OP, and the second support member 11 may have a ring shape that surrounds the side surface of the first support member 12 via the first elastic member 13. The object OP and the first support member 12 may be one structure, in which case a part of the structure is the object OP and another part is the first support member 12. In this case, a clear boundary between the object OP and the first support member 12 may or may not exist.

[0013] The worm gear 3 may include a worm wheel 31 connected to the feed screw 2, and a worm 32 screwed to the worm wheel 31. The worm wheel 31 may be connected to the feed screw 2 so that the rotation of the worm wheel 31 can be transmitted to the feed screw 2. The support mechanism 50 may also include a second elastic member 4. The second elastic member 4 may apply a holding force to the worm wheel 31 via the worm 32 so as to offset at least a part of the torque that the feed screw 2 receives due to the restoring force of the first elastic member 13, thereby functioning to hold the position of the feed screw 2. The holding force is smaller than the force required to rotate the worm wheel 31. The holding force is applied from the second elastic member 4 to the worm wheel 31 via a frictional force between the tooth surface of the worm 32 and the tooth surface of the worm wheel 31. The second elastic member 4 may be supported directly by the second support member 11, or indirectly via another member.

[0014] The support mechanism 50 may further include a bearing 5 that supports the worm 32. The bearing 5 may be supported directly by the second support member 11 or indirectly via another member. The second elastic member 4 may apply an elastic force (restoring force) to the worm 32 via the bearing 5. Such a configuration is advantageous for enabling smooth rotation of the worm 32. On the other hand, the second elastic member 4 may be arranged to apply an elastic force (restoring force) to the worm 32 directly without via the bearing 5. Alternatively, the second elastic member 4 may be arranged to rotate together with the worm 32.

[0015] The feed screw 2 and the worm gear 3 may constitute a pressing mechanism 10 that applies a pressing force to the first support member 12 to adjust the position of the object OP. The input to the pressing mechanism 10 is a rotational force that rotates the worm 32. This rotational force may be applied to the worm 32 by a manual operation by an operator or by a motor. The worm gear 3 functions as a reducer, and the rotational input to the worm 32 is output as the rotation of the worm wheel 31 while being decelerated by the worm gear 3. The rotational output of the worm wheel 31 is input to the feed screw 2 and converted into a linear force by the feed screw 2, which becomes a pressing force for the first support member 12. The configuration in which the worm 32 is rotated by a motor enables remote adjustment of the position of the object OP. The concept of adjusting the position of the object OP may include adjustment of the overall position or center of gravity position of the object OP, as well as adjustment of the position of a local part of the object OP, that is, adjustment of the deformation of the object OP and the attitude of the object OP.

[0016] When a pressing force is applied to the first support member 12 by the pressing mechanism 10, the first support member 12 is elastically deformed, and the feed screw 2 receives a corresponding restoring force (elastic force). At this time, if there is no rotational input to the worm 32, it is desirable that the restoring force balances the frictional force of the threaded portion of the feed screw 2 (more specifically, the frictional force between the tooth surface of the nut portion and the tooth surface of the screw shaft). In other words, it is desirable that the feed screw 2 has an irreversible property (generally called self-locking) that prevents it from being rotated by receiving a force in the direction of the screw shaft. It is also desirable that the worm gear 3 has an irreversible property (self-locking) that prevents the rotation of the worm wheel 31 from rotating the worm 32.

[0017] 1A, 1B, and 1C, the rotating shafts of the feed screw 2 and the worm wheel 31 are supported by bearings 6, and the movement of the rotating shafts in the thrust direction is restricted. Although the bearings 6 are not essential, it is desirable to provide the bearings 6 in order to facilitate smooth rotation of the feed screw 2 and the worm wheel 31. The bearings 6 can also function to receive a reaction force (reaction forces in the thrust and radial directions of the rotating shafts of the feed screw 2 and the worm wheel 31) when the worm gear 3 is driven.

[0018] The principle of suppressing the positional fluctuation of the object OP due to disturbance will be described below. The positional fluctuation of the object OP due to disturbance can be caused by linear displacement of the feed screw 2, which occurs when the rotary shaft of the feed screw 2 is rotated by the disturbance in a state where the feed screw 2 is stopped while receiving torque due to the restoring force of the first elastic member 13 and there is no rotational input to the worm 32. In other words, the positional fluctuation of the object OP due to disturbance occurs due to loosening (rotation) of the feed screw 2 due to the disturbance.

[0019] The loosening of the feed screw 2 due to disturbance is suppressed by the action of the worm gear 3 and the second elastic member 4. For example, when the feed screw 2 receives the restoring force of the first elastic member 13 and there is no rotation input to the worm 32, if there is no second elastic member 4, no force acts on the meshing tooth surface between the worm 32 and the worm wheel 31. This is because the rotation of the worm wheel 31 is stopped due to the irreversibility of the feed screw 2 connected to the worm wheel 31. An input to maintain the rotation of the worm 32 (for example, a holding torque by a pulse motor) may be constantly applied, but in that case the configuration becomes complicated. Therefore, by providing the second elastic member 4, the elastic force of the second elastic member 4 can be constantly applied to the meshing tooth surface of the worm gear 3. This allows a force against the rotation of the worm wheel 31 due to the loosening of the feed screw 2 to act on the meshing tooth surface, suppressing the position fluctuation of the object OP due to disturbance.

[0020] The second elastic member 4 can apply an elastic force in the thrust direction of the worm 32 as illustrated in FIG. 1A, FIG. 1B, and FIG. 1C. However, this is merely an example, and the second elastic member 4 may apply a force having a component in at least one direction of the thrust direction of the worm 32, the radial direction of the worm wheel 31, and the thrust direction of the worm wheel 31 to the worm 32. The second elastic member 4 may also apply an elastic force to the worm 32 that rotates the worm 32 about its axis. Alternatively, the second elastic member 4 may apply an elastic force to the worm 32 that rotates the worm 32 about the axis of the worm wheel 31. In either case, an elastic force is applied to the meshing tooth surface of the worm gear 3. Here, the second elastic member 4 may be configured to apply an elastic force to the meshing tooth surface of the worm gear 3 so as to oppose the rotation of the worm wheel 31 due to loosening of the screw. This meshing tooth surface corresponds to a tooth surface that meshes when the feed screw 2 is driven via the worm gear 3 so that the feed screw 2 advances in a linear direction that increases the restoring force (elastic force) of the first elastic member 13. This reduces the positional fluctuation of the object OP due to disturbances in a state in which the pressing force of the pressing mechanism 10 on the first support member 12 is maintained constant.

[0021] FIG. 2A is a schematic perspective view showing the configuration of the support mechanism 50 in the first configuration example of the first embodiment. FIG. 2B is a cross-sectional view of the support mechanism 50 in FIG. 2A cut along the line AA. Matters not mentioned in the first configuration example may follow the above description. In the first configuration example, the support mechanism 50 includes a first support member 12 that supports an object OP, and a second support member 11 that supports the first support member 12 via a first elastic member 13. The first support member 12 and the second support member 11 are connected to and integrated with the first elastic member 13. The support mechanism 50 in the first configuration example includes an actuator 7 that applies a rotation input to the worm 32 of the worm gear 3. The actuator 7 can rotate the worm 32 so that a pressing force is applied to the first support member 12 via the worm gear 3 and the feed screw 2. When the actuator 7 applies a pressing force to the first support member 12 via the worm gear 3 and the feed screw 2, the first elastic member 13 elastically deforms, and the first support member 12 moves, thereby moving the object OP. The elastic deformation of the first elastic member 13 means that the first elastic member 13 generates a restoring force. Moreover, an increase in the elastic deformation of the first elastic member 13 means that the restoring force of the first elastic member 13 increases.

[0022] The first elastic member 13 may be a leaf spring. The leaf spring may be arranged so as to be difficult to deform in the direction of the weight of the first support member 12, but easy to deform in the direction of the pressure applied by the feed screw 2 to the first support member 12. This makes it possible to both support and move the first support member 12 and the object OP.

[0023] As described above, the feed screw 2 can be supported by the second support member 11 via the bearing 6. The feed screw 2 can be, for example, a "slide screw" composed of a nut portion 21 on the female thread side and a screw shaft 22 on the male thread side. The rotation of the nut portion 21 is restricted by a linear shaft 23, and it can move linearly only in the axial thrust direction. The linear shaft 23 is supported by the second support member 11, and the rotation of the screw shaft 22 moves the nut portion 21 linearly. The nut portion 21 moves in the linear motion direction and comes into contact with the first support member 12, so that the first support member 12 is pressed by the nut portion 21. The bearing 6 is, for example, a deep groove ball bearing or an angular ball bearing, and is fixed in the axial thrust direction and the radial direction.

[0024] 2A and 2B, the worm gear 3 includes a worm wheel 31 connected to the screw shaft 22, and a worm 32 supported by the second support member 11 via a bearing 5. The worm 32 is supported movably in its thrust direction, and a restoring force is applied in one direction by a leaf spring 41 serving as a second elastic member, pressing the worm wheel 31 via the bearing 5.

[0025] The rotating shaft of the worm 32 is connected to a pulse motor serving as the actuator 7 via a coupling 8, which absorbs the movement of the worm 32 in the axial thrust direction and accurately transmits the rotation of the actuator 7 to the worm 32. The actuator 7 can accurately impart an amount of rotation to the worm 32, and therefore can accurately adjust the force applied to the first support member 12. A pulse motor that can be used as the actuator 7 is superior to a servo motor in that it can accurately displace the first support member 12.

[0026] When the rotation input of the pulse motor as the actuator 7 drives the worm gear 3 and the nut portion 21 of the feed screw 2 presses the first support member 12, the first elastic member 13 is elastically deformed. After that, even if the input from the actuator 7 is cut off, the elastic deformation of the first elastic member 13 is maintained by the feed screw 2 receiving the restoring force of the first elastic member 13. At this time, even if a torque that tries to loosen the screw shaft 22 acts on the feed screw 2 due to, for example, disturbance vibration, the elastic force of the leaf spring 41 as the second elastic member 4 applies a holding force to the worm wheel 31 via the worm 32 so as to offset at least a part of the torque. This increases the torque required to loosen the screw shaft 22, thereby reducing the occurrence of screw loosening.

[0027] On the other hand, if the elastic force of the leaf spring 41 as the second elastic member 4 is too large, the elastic force may rotate the worm wheel 31. Therefore, the elastic force of the leaf spring 41 as the second elastic member 4 may be limited so that the worm gear 3 is not driven by the elastic force of the leaf spring 41. When applying an elastic force in the thrust direction of the worm 32 as shown in Figs. 2A and 2B, it is desirable to design or adjust the elastic force to be less than 2TWH / P, where TWH is the maximum torque required to start rotating the screw shaft 22 and P is the reference circle diameter of the worm wheel 31. In addition, taking into account the mechanical efficiency η (<1), it may be less than 2ηTWH / P. In other words, it is desirable that the holding force is smaller than the force required to rotate the worm wheel 31. As a result, the worm gear 3 is not driven only by the elastic force of the leaf spring 41 as the second elastic member 4, and the pressing force can be adjusted only by the rotation input of the actuator 7.

[0028] FIG. 3 is a schematic perspective view showing the configuration of the support mechanism 50 in the second configuration example of the first embodiment. The matters not mentioned in the second configuration example may follow the above description. In the second configuration example, the feed screw 2 is a micrometer head composed of a sleeve (nut part) 24 on the female thread side and a spindle (screw shaft) 25 on the male thread side. When the sleeve 24 is fixed to the second support member 11 and the spindle 25 is rotated, the spindle 25 moves linearly in the thrust direction while rotating. The first support member 12 may be pressed by the linearly moving spindle 25. Using a micrometer head as the feed screw 2 is advantageous for reducing costs. However, since the spindle 25 moves linearly while rotating, a mechanism that allows this may be provided at the connection point between the spindle 25 and the worm wheel 31. For example, the worm wheel 31 is supported by a bearing 6, and the worm wheel 31 and the spindle 25 may be connected using a spline shaft structure. This allows rotation to be transmitted while allowing movement in the thrust direction. Alternatively, the same effect can be achieved by connecting via a coupling or pinion gear.

[0029] As in the first configuration example, the worm 32 is supported so as to be movable in the thrust direction, and a restoring force is applied in one direction by the leaf spring 41 as the second elastic member 4, and the worm 32 is pressed against the worm wheel 31. The rotation shaft of the worm 32 is connected to a pulse motor as the actuator 7 via a coupling 8, and the coupling 8 absorbs the movement of the worm 32 in the thrust direction and accurately transmits the rotation of the actuator 7 to the worm 32. As a result, even if a torque acts on the micrometer head to loosen the spindle 25 due to, for example, disturbance vibration, the elastic force of the leaf spring 41 applies a holding force to the worm wheel 31 via the worm 32 so as to offset at least a part of the torque. As a result, the torque required to loosen the spindle 25 can be increased, and the occurrence of screw loosening can be reduced.

[0030] FIG. 4 is a schematic perspective view showing the configuration of the support mechanism 50 in the third configuration example of the first embodiment. The matters not mentioned in the third configuration example may follow the above description. In the third configuration example, the rotating shaft of the feed screw and the worm wheel 31 is supported by a shaft support member 61 connected to the second support member 11. On the other hand, the rotating shaft of the worm 32 is supported by a shaft support member 51. The shaft support member 51 is connected to the shaft support member 61 via a compression coil spring 42 as the second elastic member 4, and an elastic force is applied to the worm wheel 31 in the radial direction of the worm wheel 31. The shaft support member 51 may be connected to the shaft support member 61 so as to be movable in the radial direction, which is the direction in which the elastic force is applied, and so as to be immovable in other directions.

[0031] In the third configuration example, the worm 32 is pressed against the worm wheel 31 in the radial direction of the worm wheel 31. This allows the elastic force of the second elastic member 4 to be applied to the meshing tooth surface of the worm gear 3 when driving the feed screw so that the feed screw advances in a direction that increases the restoring force (elastic force) of the first elastic member 13. This generates a frictional force on the meshing tooth surface, reducing positional fluctuation of the object OP due to disturbance.

[0032] However, pressing the worm 32 against the worm wheel 31 in the radial direction of the worm wheel 31 will result in meshing with the opposite tooth surface in addition to the meshing tooth surface described above. In other words, this means eliminating the backlash of the worm gear 3. In general, a worm gear absorbs axial vibration caused by machining errors and assembly errors of the worm gear by an appropriate amount of backlash, and achieves smooth rotation. When the worm gear 3 is driven, it is desirable that the worm 32 moves against the elastic force of the compression coil spring 42 as the second elastic member 4, so that the above-mentioned machining errors and assembly errors can be absorbed. Therefore, as shown in FIG. 4, when an elastic force is applied to the worm wheel 31 in the radial direction of the worm wheel 31, a design can be made so that an elastic force less than Fr is applied to the worm wheel 31. Here, Fr is the radial force of the worm wheel 31 acting on the worm 32 when the actuator starts to drive the worm gear 3.

[0033] FIG. 5 is a schematic perspective view showing the configuration of the support mechanism 50 in the fourth configuration example of the first embodiment. The matters not mentioned in the fourth configuration example may follow the above description. In the fourth configuration example, the rotation shaft of the feed screw and the worm wheel 31 is supported by a shaft support member 61 connected to the second support member 11. On the other hand, the rotation shaft of the worm 32 is supported by a shaft support member 51. The shaft support member 51 is connected to the shaft support member 61 via a compression coil spring 42 as the second elastic member 4, and an elastic force is applied to the worm wheel 31 in the thrust direction of the rotation shaft of the worm wheel 31. The shaft support member 51 may be connected to the shaft support member 61 so as to be movable in the thrust direction, which is the direction in which the elastic force is applied, and so as to be immovable in other directions.

[0034] In the fourth configuration example, the worm 32 is pressed against the worm wheel 31 in the thrust direction of the worm wheel 31. This allows the elastic force of the second elastic member 4 to be applied to the meshing tooth surface of the worm gear 3 when driving the feed screw so that the feed screw advances in a direction that increases the restoring force (elastic force) of the first elastic member 13. This generates a frictional force on the meshing tooth surface, reducing the positional fluctuation of the object OP due to disturbance.

[0035] On the other hand, if the force pressing the worm 32 in the thrust direction of the worm wheel 31 is too large, there is a possibility that the worm wheel 31 will rotate due to the elastic force. Therefore, as shown in Fig. 5, when an elastic force is applied to the worm wheel 31 in the thrust direction of the worm wheel 31, a design can be made so that an elastic force less than FX is applied to the worm wheel 31. Here, Fx is the force in the thrust direction of the worm wheel 31 acting on the worm 32 when the actuator starts to drive the worm gear 3. This prevents the worm gear 3 from being driven only by the elastic force of the compression coil spring 42, and makes it possible to adjust the pressing force only by the rotation input.

[0036] Fig. 6A is a schematic perspective view showing the configuration of a support mechanism 50 of the second embodiment. Fig. 6B is a cross-sectional view of the support mechanism 50 of Fig. 6A taken along line AA. Matters not mentioned in the second embodiment may follow the first embodiment (including the first to fourth configuration examples).

[0037] In the second configuration example, the support mechanism 50 further includes a limiting unit 9 that limits the movable range of the worm 32. The limiting unit 9 is useful for improving the positional accuracy of the linear displacement of the feed screw 2 and for adjusting the pressing force of the feed screw 2 against the first support member 12 with high accuracy. If the movable range of the worm 32 is not limited, the worm gear 3 starts to drive after moving to a position where the reaction force of the worm gear 3 when it is driven and the elastic force of the second elastic member 4 are balanced when the worm gear 3 presses the first support member 12 in response to the rotation input to the worm 32. However, the reaction force of the worm gear 3 when it is driven is uncertain because it changes depending on the input torque of the worm 32. As a result, when a constant rotation input (for example, an angle) is given to the worm 32, the driving amount of the worm gear 3 varies, and the linear displacement amount of the feed screw 2 is not constant. It is desirable to limit the movable range of the worm 32 so that the worm 32 always moves to the end of the movable range while the worm gear 3 is being rotationally driven, and the worm gear 3 is driven at the same position every time. In this case, the worm 32 needs to move to the end of the movable range before the reaction force acting on the worm 32 during driving and the elastic force of the second elastic member 4 are balanced as the worm 32 moves. A design that achieves this can be made by calculating the driving reaction force of the worm gear 3 from the minimum input torque to the worm 32 required to drive the worm gear 3.

[0038] 6A and 6B, the second elastic member 4 applies an elastic force to the worm 32 in the thrust direction of the worm 32, so the movable direction of the worm 32 and the direction that limits the movable range are the thrust direction of the worm 32. However, it is only necessary that the direction in which the second elastic member 4 generates the elastic force, the movable direction of the worm 32, and the direction that limits the movable range are the same. In other words, the movable direction can be a direction that includes at least one of the thrust direction of the worm 32, the radial direction of the worm wheel 31, and the thrust direction of the worm wheel 31 as a component, and the movable range can be limited.

[0039] 7 is a schematic perspective view showing the configuration of a support mechanism 50 according to the third embodiment. Matters not mentioned in the third embodiment may follow the first embodiment (including the first to fourth configuration examples) or the second embodiment.

[0040] The support mechanism 50 may include a first support member 12 that supports an object OP, a second support member 11 that supports the first support member 12 via a first elastic member 13, and a pressing mechanism 10 arranged to apply a force to the first support member 12. As described above, the pressing mechanism 10 may include a feed screw 2 and a worm gear 3. In one example, the object OP has a circular shape, the first support member 12 has a ring shape that surrounds the side surface (cylindrical surface) of the object OP, and the second support member 11 may have a ring shape that surrounds the side surface of the first support member 12 via the first elastic member 13. The object OP and the first support member 12 may be one structure, in which case a part of the structure is the object OP and another part is the first support member 12. In addition, in this case, there may or may not be a clear boundary between the object OP and the first support member 12. In the third embodiment, the feed screw of the pressing mechanism 10 is configured to apply a force to the first elastic member 13, thereby applying a force to the first support member 12.

[0041] The first elastic member 13 may be a leaf spring that easily deforms in the direction of pressing the first elastic member 13 by the pressing mechanism 10 while supporting the weight of the object OP and the first support member 12. However, the first elastic member 13 may be a spring of another shape, or may not support the weight of the object OP and the first support member 12. The first elastic member 13 may have, for example, a first leaf spring coupled to the first support member 12, a second leaf spring coupled to the second support member 11, and a connecting portion that connects the first leaf spring and the second leaf spring, and the feed spring of the pressing mechanism 10 may apply a pressing force to the connecting portion. The pressing mechanism 10 applies a pressing force to the first elastic member 13, causing the first elastic member 13 to elastically deform, thereby adjusting the positions of the first support member 12 and the object OP. The support mechanism 50 may include a plurality of first elastic members 13 and a plurality of pressing mechanisms 10. Such a configuration is advantageous for adjusting the position of the center of gravity of the object OP and for adjusting the attitude of the object OP.

[0042] The function provided by the second elastic member 4 will be explained with reference to Figs. 8 and 9. The feed screw 2 receives a torque T due to the restoring force F1 of the first elastic member 13. The torque T can act to loosen the feed screw 2. The second elastic member 4 applies a holding force F2 to the worm wheel 31 via the worm 32 so as to offset at least a portion of the torque T, thereby maintaining the position of the feed screw 2. A force to offset the remainder of the torque T can be provided by the self-lock described above.

[0043] FIG. 10 illustrates an exposure apparatus 100 including an optical system in which the support mechanism 50 is incorporated. The exposure apparatus 100 may be configured to project a pattern of an original 102 onto a substrate 109 and expose the substrate 109 to light. The exposure apparatus 100 may include an original stage 103 that holds the original 102, an illumination optical system 101 that illuminates the original 102, a projection optical system 105 that projects the pattern of the original 102 onto the substrate 109, and a substrate stage 106 that holds the substrate 109. The projection optical system 105 is an example of an optical system in which the support mechanism 50 is incorporated. The illumination optical system 101 is another example of an optical system in which the support mechanism 50 is incorporated. The exposure apparatus 100 may include a measuring instrument 104 that measures the position of the original 102 or the relative position between the original 102 and the substrate 109. The exposure apparatus 100 may also include a measuring instrument 107 that measures the position of the substrate stage 106. The exposure apparatus 100 may also include a metrology instrument 110 that measures the height of the substrate 109 .

[0044] In the exposure apparatus 100, it is required to adjust the positions of multiple optical elements that make up the projection optical system 105 with high precision. In addition, a large optical barrel is used in the projection optical system 105. For this reason, a long process is required to disassemble and adjust the barrel that makes up the projection optical system 105, and then to reassemble the disassembled barrel. The same is true for the illumination optical system 101. By incorporating a support mechanism 50 in the projection optical system 105, it is possible to adjust the positions of the optical elements without disassembling the barrel of the projection optical system 105. The same is true for the illumination optical system 101.

[0045] Next, a method for manufacturing an article (such as a semiconductor IC element, a liquid crystal display element, or a MEMS) using the exposure apparatus 100 will be described. The method for manufacturing an article may include an exposure step of exposing a substrate 109 using the exposure apparatus 100, a development step of developing the substrate 109 that has undergone the exposure step, and a processing step of processing the substrate 109 that has undergone the development step to obtain an article. The substrate 109 provided to the exposure step is a substrate (such as a wafer or a glass substrate) coated with a photosensitive agent. The processing step may include, for example, etching, resist peeling, dicing, bonding, packaging, and other steps.

[0046] The disclosure of this specification and the accompanying drawings includes the following. (Item 1) A first support member that supports an object; a second support member that supports the first support member via a first elastic member; a lead screw disposed to apply a force to the first support member; a worm gear including a worm wheel connected to the feed screw and a worm screwed onto the worm wheel; a second elastic member that applies a holding force to the worm wheel via the worm so as to offset at least a portion of the torque that the feed screw receives due to the restoring force of the first elastic member, thereby holding the position of the feed screw; A support mechanism comprising: (Item 2) the retaining force is less than the force required to rotate the worm wheel; 2. The support mechanism according to item 1, (Item 3) The holding force is applied to the worm wheel by the second elastic member applying a force in a thrust direction of the worm to the worm. 3. The support mechanism according to item 2, (Item 4) The holding force is applied to the worm wheel by the second elastic member applying a radial force of the worm wheel to the worm. 3. The support mechanism according to item 2, (Item 5) The holding force is applied to the worm wheel by the second elastic member applying a force in a thrust direction of the worm wheel to the worm. 3. The support mechanism according to item 2, (Item 6) the object has a circular shape, the first support member has a ring shape surrounding a side surface of the object, and the second support member has a ring shape surrounding a side surface of the first support member via the first elastic member. 6. The support mechanism according to any one of items 1 to 5, (Item 7) Further comprising a bearing for supporting the worm. 7. The support mechanism according to item 6, characterized in that (Item 8) The bearing is supported by the second support member. 8. The support mechanism according to item 7, characterized in that (Item 9) The second elastic member applies a force to the worm via the bearing. 9. The support mechanism according to item 8, characterized in that (Item 10) and an actuator that rotates the worm so that a force is applied to the first support member via the worm gear and the feed screw. 10. The support mechanism according to any one of items 7 to 9, (Item 11) Further, a limiting portion that limits a movable range of the worm is provided. 7. The support mechanism according to any one of items 1 to 6, (Item 12) and an actuator that rotates the worm so that a force is applied to the first support member via the worm gear and the feed screw. 12. The support mechanism according to item 11, (Item 13) While the actuator is rotating the worm, the worm moves to the end of the movable range by a driving reaction force. 13. The support mechanism according to item 12, characterized in that (Item 14) The feed screw includes a nut portion and a screw shaft. 14. The support mechanism according to any one of items 1 to 13, (Item 15) The feed screw is a micrometer head. 14. The support mechanism according to any one of items 1 to 13, (Item 16) The spindle of the micrometer head and the worm wheel are connected by a spline shaft structure. 16. The support mechanism according to item 15, characterized in that (Item 17) the first elastic member is connected to a first location of the first support member, The lead screw is configured to apply a force to a second location of the first support member that is different from the first location. 17. The support mechanism according to any one of items 1 to 16, (Item 18) The lead screw is configured to apply a force to the first support member by applying a force to the first elastic member. 17. The support mechanism according to any one of items 1 to 16, (Item 19) An optical element; The support mechanism according to any one of items 1 to 18, The support mechanism supports the optical element as the object. An optical system characterized by: (Item 20) 20. An exposure apparatus that projects a pattern of an original onto a substrate and exposes the substrate, comprising the optical system according to item 19. (Item 21) An exposure step of exposing a substrate by the exposure apparatus according to item 20; a developing step of developing the substrate that has been subjected to the exposure step; a processing step of obtaining an article by processing the substrate that has been subjected to the developing step; A method for manufacturing an article, comprising:

[0047] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0048] 50: support mechanism, OP: object, 2: feed screw, 3: worm gear, 4: 2 elastic member, 10: pressing mechanism, 11: 2nd support member, 12: 1st support member, 13: 1st elastic member, 31: worm wheel, 32: worm,

Claims

1. A first support member that supports an object; a second support member that supports the first support member via a first elastic member; a lead screw disposed to apply a force to the first support member; a worm gear including a worm wheel connected to the feed screw and a worm screwed onto the worm wheel; a second elastic member that applies a holding force to the worm wheel via the worm so as to offset at least a portion of the torque that the feed screw receives due to the restoring force of the first elastic member, thereby holding the position of the feed screw; A support mechanism comprising:

2. the retaining force is less than the force required to rotate the worm wheel; The support mechanism according to claim 1 .

3. The holding force is applied to the worm wheel by the second elastic member applying a force in a thrust direction of the worm to the worm. The support mechanism according to claim 2 .

4. The holding force is applied to the worm wheel by the second elastic member applying a force in a radial direction of the worm wheel to the worm. The support mechanism according to claim 2 .

5. The holding force is applied to the worm wheel by the second elastic member applying a force in a thrust direction of the worm wheel to the worm. The support mechanism according to claim 2 .

6. the object has a circular shape, the first support member has a ring shape surrounding a side surface of the object, and the second support member has a ring shape surrounding a side surface of the first support member via the first elastic member. The support mechanism according to claim 1 .

7. Further comprising a bearing for supporting the worm.

7. The support mechanism according to claim 6.

8. The bearing is supported by the second support member. The support mechanism according to claim 7 .

9. The second elastic member applies a force to the worm via the bearing. The support mechanism according to claim 8 .

10. an actuator that rotates the worm so that a force is applied to the first support member via the worm gear and the feed screw; The support mechanism according to claim 7 .

11. Further, a limiting portion that limits a movable range of the worm is provided. The support mechanism according to claim 1 .

12. an actuator that rotates the worm so that a force is applied to the first support member via the worm gear and the feed screw; The support mechanism according to claim 11 .

13. While the actuator is rotating the worm, the worm moves to the end of the movable range by a driving reaction force. The support mechanism according to claim 12 .

14. The feed screw includes a nut portion and a screw shaft. The support mechanism according to claim 1 .

15. The feed screw is a micrometer head. The support mechanism according to claim 1 .

16. The spindle of the micrometer head and the worm wheel are connected by a spline shaft structure.

16. The support mechanism according to claim 15.

17. the first elastic member is connected to a first location of the first support member, The lead screw is configured to apply a force to a second location of the first support member that is different from the first location. The support mechanism according to claim 1 .

18. The lead screw is configured to apply a force to the first support member by applying a force to the first elastic member. The support mechanism according to claim 1 .

19. An optical element; and a support mechanism according to any one of claims 1 to 18, The support mechanism supports the optical element as the object. An optical system characterized by:

20. 20. An exposure apparatus for projecting a pattern of an original onto a substrate and exposing the substrate, comprising the optical system according to claim 19.

21. an exposure step of exposing a substrate by the exposure apparatus according to claim 20; a developing step of developing the substrate that has been subjected to the exposure step; a processing step of obtaining an article by processing the substrate that has been subjected to the developing step; A method for manufacturing an article, comprising:

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