JPH0463649A - Rotary translational stage device - Google Patents

Abstract

PURPOSE:To obtain a rotary translational stage device with high rigidity and high precision by combining a rotary drive system by the friction drive and a translational drive system by wedges. CONSTITUTION:Wedge members 1, 2 are coupled with each other to form parallel planes 21, 22, and a wafer chuck 4 is fixed on them. When one of the wedge members 1, 2 is moved in the arrow direction by a linear motor 6, the thickness between the parallel planes 21, 22 is changed, and the position of the wafer chuck 4 is vertically changed. The wedge member 1 is connected to a rotary stage 7 with a parallel link spring 5, the parallel link spring 5 restricts the wedge member 1 in the vertical direction in the figure, an elastic force is applied downward, and the wedge member 1 is fixed. A friction roller 10 is friction- coupled on the outer periphery of the cylindrical side wall of the rotary stage 7 and driven by a motor 11, an idler 12 is arranged at the other corresponding position, and the smooth rotating motion of the rotary stage 7 is compensated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a stage device on which an object is placed and moved, and more particularly to a highly accurate rotational translation stage device.

E. Prior Art] In an exposure stage apparatus for VLSI manufacturing, highly accurate positioning with an error of 0.01 μm to 0.1 μm within the stage plane is required, for example.

When loading a semiconductor wafer onto such a high-precision stage device, there may be variations in the thickness of the semiconductor wafer,
The problem is the variation in the rotational direction that occurs during loading. Therefore, an adjustment NWA structure in the thickness direction of the wafer and a rotation adjustment mechanism around the optical axis of the wafer (the axis of incidence of X-rays, electron beams, etc. are also called optical axis) are required. The adjustment mechanism in the thickness direction is preferably capable of correcting differences in thickness due to differences in the type (diameter) of wafers, and preferably has a stroke of several hundred μm or more. Further, it is desired that the rotation adjustment mechanism has a rotation angle stroke of approximately ±1 degree or more.

FIGS. 5(A), 5(B), and 5(C) show examples of conventional rotary translation stage devices for such purposes.

FIG. 5(A) is a schematic diagram showing the overall configuration of the rotation translation stage device. A rotary stage 53 is held on a base 51 via a rotatable bearing 52. Three sets of eccentric cam mechanisms 56 as shown in FIG. 5(B) are arranged on the rotation stage 53. A chuck plate 58 is placed on the three sets of eccentric cam mechanisms 56.

In FIG. 5(B), each eccentric cam mechanism 56 is connected to the motor 5.
5 and an eccentric cam 54, the shaft of the eccentric cam 54 is coupled to the drive shaft of a motor 55. By driving the motor 55, when the eccentric cam 54 rotates, the distance M (height) from the center of the shaft to the periphery of the cam directly above changes, and the chuck grating 58 placed thereon is moved up and down. let

By driving three sets of eccentric cam mechanisms in synchronization, the chuck plate 58 is translated in the vertical direction in the figure while being kept horizontal.

Note that in order to attract the chuck plate 58 to the rotation stage 53, springs 59 are coupled between the chuck plate 58 and the rotation stage 53 at a plurality of locations.

An arm 61 is coupled to the bottom surface of the rotation stage 53 and protrudes outward to constitute a rotation mechanism for the rotation stage 53 as shown in FIG. 5(C).

A linear actuator 64 consisting of a motor 62 and a pole screw 63 is engaged with an arm 61 protruding from the rotation stage 53. When the motor 62 is rotated, the tip of the ball screw 63 moves linearly in the direction of the arrow. Note that the spring 6
6 is provided between the arm 61 of the rotation stage 53 and the base 51.

In this way, a rotation translation stage device is constructed. Translational movement can be performed by driving the eccentric cam 56, and rotational movement can be performed by driving the motor 62.

According to such a configuration, since the chuck grating 58 is supported and driven by three sets of eccentric cam mechanisms, the sameness is limited to the weakest part of the eccentric cam mechanisms. Therefore, it is not easy to make the rigidity sufficiently high, and although the configuration shown in FIG. 5(A) is relatively stable when placed horizontally as shown, the stage surface When used as a vertical stage facing vertically, holding the chuck plate becomes a problem. A kite or the like that can counteract the gravity of the chuck plate may be provided, but the play in the guide tends to reduce accuracy and complicate the mechanism.

In addition, if the mechanical rigidity or movement accuracy of the stage correction mechanism, such as the translation cam or linear actuator mentioned above, is low, the positioning accuracy of the stage will deteriorate. If posture control is performed using the motor, the heat generated by the motor causes thermal expansion of the mechanical members, which deteriorates positional accuracy.

Problem 1 to be Solved by the Invention As explained above, according to the conventional technology, it is not easy to obtain a high-precision rotary translation stage, especially a rotary translation stage whose stage surface is oriented vertically. There was a problem with the posture correction mechanism.

An object of the present invention is to provide a rotation translation stage device that has high rigidity and high precision.

"Means for Solving the Problems" A rotary translation stage device of the present invention includes a base that provides physical support, a stage member for holding an object, and a rotary bearing supported between the base and the stage member. , a rotating stage having a circumferential surface, a friction drive means that frictionally engages with the circumferential surface of the rotating stage and drives the rotating stage in the circumferential direction, and a pair of m pairs disposed between the base and the stage member. and a translation mechanism that changes the thickness by relatively moving the wedge members.

[Function] Since the rotary stage is driven and rotated in the circumferential direction by friction drive through frictional engagement, it is easy to achieve high precision in the direction of rotation, and by realizing translational movement with the wedge member, sufficiently high toughness can be achieved. It is possible to realize a translation mechanism with

Furthermore, when the device is stationary, highly accurate translational drive can be achieved with almost no heat generation.

A rotary translation stage device that combines these translation mechanisms and rotation mechanisms has high toughness and can suppress heat generation, so it is easy to maintain high precision during operation.

F Example The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram schematically explaining a stage drive mechanism. Further, FIG. 2 is a diagram showing an overview of the drive m-ellipse in a state where the rotary stage of FIG. 1 is rotated approximately 90 degrees.

A pair of wedge members 1.2, as shown in FIG. 2, engage each other to define parallel planes 21.22 on either side of which a wafer chuck 4 is fixed. A semiconductor wafer 3 is placed on the wafer chuck 4. When one (2) of the pair of wedge members 1.2 is moved in the direction of the arrow shown in FIG. 2 by the linear motor 6, the thickness between the parallel planes 21 and 22 formed by the pair of wedge members 1.2 changes. This change causes the position of the wafer chuck 4 to change up and down. Arranged on the upper side of the pair of wedge members 1.2! The wedge member 1 thus formed is coupled to a rotation stage 7 by a parallel link spring 5, as shown in FIG. The parallel link spring restrains the wedge member 1 in the vertical direction in the figure, applies an elastic force downward, and applies a force that presses the upper wedge member 1 against the lower wedge member 2 and the bottom surface of the rotation stage 7. There is. Therefore, a force due to the static traction coefficient acts on the contact surface, and the wedge member is fixed. The lower wedge member 2 is placed on a rotation stage 7, and is allowed to slide and translate in the direction of the arrow by a linear motor 6.

The rotation stage 7 is rotatably supported on a base 9 by a thrust bearing 8 and has a cylindrical rpJ wall.
A friction roller 10 is frictionally engaged with the outer periphery of the cylindrical side wall of the rotation stage 7 and is driven by a motor 11 . In addition, an idler 12 is arranged at another symmetrical position of the rotation stage 7 to ensure smooth rotational movement of the rotation stage 7.

FIG. 3 is a schematic plan view for explaining the rotational drive of the rotation stage. The friction roller 10 is frictionally engaged at one location on the outer periphery of the side wall of the rotation stage 7, and there are two contrasting positions with respect to the friction roller 10. Idler 12
is arranged rotatably in contact with the outer periphery of the rotation stage 7. The friction roller 10 is connected to a rotary motor 11 shown in FIGS. 1 and 2 below, and is rotated by the rotational driving force of the rotary motor 11. As shown in FIG. When the friction roller IO rotates, the rotation stage 7 rotates due to its friction (A), and the idler 12 also rotates.The rotation stage 7 can accurately maintain its axial position and perform rotational movements.

A wedge-based translation mechanism as shown in FIG. 4 is disposed on the upper surface of the rotation stage 7. As shown in FIG. When adjusting the pair of wedge members and changing their thickness, it is preferable to reduce the frictional force acting on the wedge members.

FIG. 4 shows a wedge mechanism having an air guide for reducing the frictional force acting on the wedge members during adjustment.In the configuration shown in FIG. The wedge member 1 has a mechanism for blowing out air from its bottom surface.
．． When air is blown out from 2, a film of air is generated between wedge members 1 and 2 and between wedge member 2 and rotating stage 7, making it possible to move wedge member 2 with almost no frictional force. become. By moving the wedge member 2 by the linear motor 6 with the frictional force reduced in this manner, it is possible to achieve highly accurate displacement of the wedge member 2.

After moving to the desired position, by stopping the air sent to the air duct 14.15, the wedge member 1.2 and the rotary stage 7 are brought into contact again and their relative positions are fixed by frictional force. Note that a duct 16 is also formed within the wafer chuck 4 and is connected to a vacuum evacuation device to form a vacuum chuck that sucks the wafer 3.

Although a configuration has been described in which air ducts 14.15 are formed in each of the lower wedge members 1.2, a configuration may also be adopted in which air is blown from an air tact provided in the lower wedge member 2 to its upper and lower surfaces. Also, other gases may be used instead of air.

Although the structure in which the translation mechanism is provided on the rotation stage has been described, the vertical relationship between the rotation mechanism and the translation mechanism may be reversed. Bearings may also be used. For example, a rotary bearing can be constructed using an air bearing or the like. When adjusting the relative position of a pair of wedge members, we have explained a mechanism in which a gas layer is formed between the wedge members and between the wedge member and its supporting member to reduce the frictional force. For example, magnetic forces or the like may be used to create a repulsive force between the wedge member and the lower support surface and between the wedge members to reduce the frictional force and cause one of the wedge members to move.

Although the description has been given using a stage device for semiconductor manufacturing equipment as an example, the present invention can be applied to a wide variety of other rotary translation stage devices such as various processing machines and measuring instruments.

Although the present invention has been described above in accordance with the examples, the present invention is not limited to these examples. For example, various modifications,
It will be obvious to those skilled in the art that improvements, combinations, etc. are possible.

f Effects of the Invention] As explained above, according to the present invention, rotational drive a! by friction drive! By combining paulownia wood and a wedge-based translational drive mechanism, the rigidity of the drive mechanism can be increased and highly accurate rotational and translational movement can be achieved.

Since the wedge member engages with a wide contact surface, it is easy to achieve high toughness, and if it is made to stand still due to frictional force, heat generation in a stable state can be reduced.

When adjusting the wedge member, if a non-contact guide mechanism is formed between the wedge members, the frictional force can be reduced and the wedge member can be moved with high precision with a small force.

Furthermore, if the upper wedge member is supported by a parallel leaf spring mechanism that is elastically deformable in a direction perpendicular to the stage surface, it is possible to guide the translational movement of the upper wedge member and generate a pressing force against the lower wedge member. , it becomes possible to improve the accuracy of translational movement and to apply sufficient static frictional force.

[Brief explanation of drawings]

FIGS. 1 and 2 show the stage drive tl! 3 is a schematic plan view to explain the drive of the rotation stage; FIG. 4 is a schematic side view to explain the drive of the wedge; 5A, 5C, and 5C are diagrams showing an example of a rotary translation stage device according to the prior art. In the figures, wedge member wafer wafer chuck parallel link spring linear motor rotary stage thrust bearing base Friction roller rotating motor idler 4, air duct exhaust tuft parallel plane

Claims (3)

[Claims] (1) a base that provides physical support; a stage member for holding an object; a rotary stage that is supported by a rotary bearing between the base and the stage member and has a circumferential surface; and a rotary stage that has a circumferential surface. friction drive means that frictionally engages with the circumferential surface of the rotary stage and drives the rotary stage in the circumferential direction; A rotation translation stage device having a translation mechanism that changes the height of the stage. (2) The rotation translation stage device according to claim 1, wherein the translation mechanism includes a mechanism for blowing gas between the pair of wedge members. (3) The rotation according to claim 1 or 2, wherein the wedge member on the stage member side of the pair of wedge members of the translation mechanism is supported by a parallel plate spring mechanism that is elastically deformable in the thickness direction. Translation stage device.