CN110412835B

CN110412835B - Holding device and optical device

Info

Publication number: CN110412835B
Application number: CN201910341338.6A
Authority: CN
Inventors: 新井学
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2018-04-26
Filing date: 2019-04-26
Publication date: 2021-09-28
Anticipated expiration: 2039-04-26
Also published as: KR102493919B1; KR20190124645A; JP2019191423A; CN110412835A; JP7090464B2

Abstract

The invention provides a holding device and an optical device, which are advantageous in terms of the positioning accuracy of a holding object relative to temperature changes even when the amount of expansion in the gravity direction is extremely small relative to the amount of expansion in the horizontal direction. The holding device includes a structure body surrounding an object, a holding member holding the object, a base member provided on an inner wall of the structure body, and a support member mounted on the base member and supporting the holding member. A1 st inclined surface is formed on a surface of the base member supporting the supporting member, the 1 st inclined surface is higher in height toward the outer side in the horizontal direction with respect to the object, a 2 nd inclined surface is formed on a surface of the supporting member supporting the holding member, the 2 nd inclined surface is higher in height toward the outer side in the horizontal direction with respect to the object in a state where the supporting member is mounted on the 1 st inclined surface, the supporting member is slidable along the 1 st inclined surface, and the holding member is slidable along the 2 nd inclined surface. The holding device maintains the positional deviation of the object within an allowable range by sliding the support member and the holding member.

Description

Holding device and optical device

Technical Field

The present invention relates to a holding device for holding an object and an optical device.

Background

In precision equipment such as a semiconductor exposure apparatus and a liquid crystal exposure apparatus, high accuracy is required for relative positions of components. Among them, a relatively high positional accuracy is also required for the optical element. Further, in recent years, the size of a semiconductor exposure apparatus, a liquid crystal exposure apparatus, or the like has become larger, and the requirement for maintaining positional accuracy has become strict in association with such a size increase.

Semiconductor exposure devices, liquid crystal exposure devices, and the like are generally used in a clean room at around 23 ℃. However, in the exposure apparatus, the temperature is increased in the vicinity of the optical path through which light of the illumination optical system, the projection optical system, and the like passes. The light source section of the illumination optical system is particularly high in temperature because of the use of a mercury lamp or the like. For example, an elliptical reflector for condensing light in a mercury lamp increases in temperature to about 100 ℃ during operation. That is, the elliptical reflector of the mercury lamp repeats temperature change in a range of about 23 ℃ to 100 ℃ every time the operation is performed and stopped.

Repetition of such temperature changes causes thermal expansion of the components according to the linear expansion coefficient, and shifts the positional relationship of the optical element. Invar, ceramics, and the like, which are low thermal expansion materials, are sometimes used to reduce positional relationship shifts, but there is a disadvantage in terms of cost when large-sized components are produced from low thermal expansion materials. Since most of the components are made of aluminum material, steel material, or the like in consideration of cost and weight, it is necessary to make a study to reduce positional deviation due to thermal expansion accompanying the increase in size of the components.

In patent document 1, in order to satisfy the requirement of high positional accuracy, a mechanism for reducing positional relationship deviation due to thermal expansion is proposed. In patent document 1, a holding member for holding an optical element is mounted on a mounting portion of a structure by 3-point support. The mounting portion has an inclined surface that forms an inclination angle set in consideration of an amount of expansion in the gravity direction and an amount of expansion in the horizontal direction due to heat. The positional relationship shift due to thermal expansion is released by the inclined surface, thereby preventing the positional shift of the optical element before and after the temperature change.

Prior art documents

Patent document

Patent document 1: japanese patent No. 5506473

Disclosure of Invention

Problems to be solved by the invention

As the device becomes larger, the diameter of the optical element becomes larger, and the thickness in the direction perpendicular to the diameter does not become larger, so that the thickness of the optical element may be extremely thin relative to the diameter. In this case, the amount of expansion in the gravity direction (thickness direction) is extremely small relative to the amount of expansion in the horizontal direction (radial direction). Therefore, in patent document 1 in which the inclination angle is uniquely determined in consideration of the amount of expansion in the gravity direction and the amount of expansion in the horizontal direction, the angle of the inclination surface becomes shallow. If the angle of the inclined surface is reduced, the possibility of the optical element being displaced in a direction in which the friction is strong due to the friction error of the inclined surfaces at 3 locations increases.

An object of the present invention is to provide a holding device which is advantageous in terms of positioning accuracy of a holding object against a temperature change even when an amount of expansion in a gravity direction is extremely small with respect to an amount of expansion in a horizontal direction, for example.

Means for solving the problems

According to the 1 st aspect of the present invention, there is provided a holding device that holds an object, characterized by having: a structure surrounding the object; a holding member that holds the object; a base member provided on an inner wall of the structure; and a support member that is mounted on the base member and supports the holding member, wherein a 1 st inclined surface is formed on a surface of the base member that supports the support member, the 1 st inclined surface having a height that increases outward in the horizontal direction with respect to the object, a 2 nd inclined surface is formed on a surface of the support member that supports the holding member, the 2 nd inclined surface having a height that increases outward in the horizontal direction with respect to the object in a state where the support member is mounted on the 1 st inclined surface, the support member is slidable along the 1 st inclined surface, the holding member is slidable along the 2 nd inclined surface, and a positional deviation of the object is maintained within an allowable range by sliding of the support member and the holding member.

According to the 2 nd aspect of the present invention, there is provided an optical device characterized by having: an optical element; and the holding device according to claim 1, wherein the holding device holds the optical element as the object.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a holding device which is advantageous in terms of positioning accuracy of a holding object against a temperature change even when, for example, an amount of expansion in a gravity direction is extremely small with respect to an amount of expansion in a horizontal direction.

Drawings

Fig. 1(a) and 1(b) are diagrams illustrating a configuration of a holding device in an embodiment.

Fig. 2(a) and 2(b) are diagrams illustrating a state in which the position and the horizontal state of the object are maintained.

Fig. 3 is a diagram showing a configuration example of the slide mechanism in the holding device.

Fig. 4 is a diagram showing another configuration example of the slide mechanism in the holding device.

Fig. 5(a) and 5(b) are views for explaining a mode in which the inclination angles of the 1 st slope and the 2 nd slope are different.

Fig. 6 is a diagram showing a configuration of an optical device according to an embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments merely show specific examples of the present invention, and the present invention is not limited to the following embodiments. All combinations of the features described in the following embodiments are not necessarily essential to solve the problems of the present invention.

< embodiment 1 >

Fig. 1(a) and 1(b) are diagrams showing the structure of a holding device 100 according to embodiment 1. The holding device 100 is a holding device that holds an object 101 as a holding object so that a positional deviation is within an allowable range even if a thermal load is generated. In the present specification and the drawings, directions are shown in an XYZ coordinate system in which the horizontal direction is an XY plane. Fig. 1(a) is a plan view of the holding device 100, and fig. 1(b) is a sectional view taken along line C-C'.

The holding device 100 includes a structure 110 surrounding the object 101, and a base member 103 is provided on an inner wall of the structure 110. The base member 103 may be configured separately from the structure 110, or may be configured integrally with the structure 110. The object 101 is held by the holding member 106. In an embodiment, the holding member 106 may include a plurality of holding members that hold the edge portion of the object 101 at a plurality of locations. The plurality of holding members are embodied as, for example, a plurality of (e.g., 3) holding members arranged at equal intervals along the outer periphery of the object 101. The base member 103 may also include a plurality of base members that support a plurality of holding members via the support member 102. In this case, the plurality of holding members are arranged at positions corresponding to the plurality of holding members. The holding member 106 is supported by the support member 102, and the support member 102 is mounted on the base member 103.

The object 101 may be an optical element such as a lens, a mirror, or the like. The support member 102 may be a ring-shaped member that surrounds the object 101. When the object 101 is a lens, a mirror, or the like, the support member 102 may be configured as a lens barrel that houses the object 101 so as to surround the object 101, as shown in fig. 1 (a). The position and horizontal state of the object 101 are based on the position and horizontal state in which the component accuracy of the components required for holding the object 101 is ensured, or the adjusted position and horizontal state.

A 1 st inclined surface 105 whose height becomes higher toward the outer side in the horizontal direction with respect to the object 101 is formed on the surface of the base member 103 that supports the support member 102. On the surface of the support member 102 that supports the holding member 106, a 2 nd inclined surface 104 is formed that becomes higher toward the outside in the horizontal direction of the object 101 in a state where the support member 102 is mounted on the 1 st inclined surface 105. The support member 102 is slidable along the 1 st inclined surface 105, and the holding member 106 is slidable along the 2 nd inclined surface 104.

The holding member 106 is interposed between the object 101 and the support member 102 in order to avoid direct sliding of the object 101 on the support member 102. At least one of the lower surfaces of the 2 nd slope 104 of the support member 102 and the lower surface of the holding member 106 may be subjected to surface treatment for smooth sliding. In the case where the object 101 can be directly slid on the support member 102, the holding member 106 is not necessary. Similarly, at least one of the 1 st inclined surface 105 of the support member 102 and the upper surface of the base member 103 may be subjected to surface treatment for smooth sliding.

Even when a thermal load is applied to the holding device 100 and the support member 102 thermally expands, the horizontal state of the object 101 is maintained by converging the positional displacement of the object 101 within the allowable range. In the present embodiment, the body 101 is made of a low thermal expansion material such as artificial quartz or ceramics, and the thermal expansion of the body 101 is extremely small with respect to the necessary accuracy of the position and horizontal state of the body 101. It is preferable that the holding member 106 holds the object 101 within a small range. Thus, the thermal expansion of the holding member 106 is extremely small with respect to the necessary accuracy of the position and horizontal state of the object 101. Further, since the heat capacity of the base member 103 is also large, the temperature rise is small, and the thermal expansion of the base member 103 is extremely small with respect to the necessary accuracy of the position and horizontal state of the object 101.

A state in which the position and the horizontal state of the object 101 can be maintained even if a heat load is applied to the holding device 100 will be described with reference to fig. 2(a) and 2 (b). Fig. 2(a) shows the same state as fig. 1 (b). Since the object 101 and the holding device 100 have axisymmetric shapes and the holding is also axisymmetric, the change in shape in the horizontal plane also occurs axisymmetrically. When a thermal load is applied to the holding apparatus 100, the support member 102 thermally expands in the horizontal direction, but the base member 103 is extremely thermally expanded, and therefore, the support member 102 deforms or moves upward along the 1 st inclined surface 105 of the base member 103. Accordingly, the object 101 and the holding member 106, which have extremely small thermal expansion, slide along the 2 nd inclined surface 104 of the support member 102 by the own weight of the holding member 106 and the object 101 so as to descend by an amount substantially equal to the amount by which the support member 102 ascends along the 1 st inclined surface 105. Thus, even if the support member 102 deforms or moves due to thermal expansion, the height of the holding member 106 (i.e., the object 101) is maintained constant. This can make the positional shift of the object 101 due to thermal expansion fall within the allowable range, and as a result, the horizontal state shift of the object 101 can be suppressed within the allowable range. As in the present embodiment, when the thermal expansion of the support member 102 is a factor affecting the necessary accuracy of the position and the horizontal state of the object 101, the 1 st inclined surface 105 and the 2 nd inclined surface 104 may have the same inclination angle.

As the object 101 increases in size, the diameter of the support member 102 also increases in size, but the thickness may not be obtained in the gravity direction due to the relationship between the weight and the space. In the case of patent document 1 (japanese patent No. 5506473), since the angle of the inclined surface is uniquely determined in consideration of the amount of expansion in the gravity direction and the amount of expansion in the horizontal direction, when the amount of expansion in the gravity direction is extremely small with respect to the amount of expansion in the horizontal direction, the uniquely determined angle of the inclined surface becomes shallow. If the angle of the inclined surface is shallow, there is a possibility that the position and hence the horizontal state are shifted due to friction or the like. In the present embodiment, the inclination angles of the 1 st inclined surface 105 and the 2 nd inclined surface 104 are not uniquely determined according to the diameter and the thickness of the support member 102, and therefore, any inclination angle can be set in consideration of friction between the 1 st inclined surface 105 and the 2 nd inclined surface 104. Therefore, even when the amount of expansion in the gravity direction is extremely small with respect to the amount of expansion in the horizontal direction, the positional displacement of the object 101 can be suppressed within the allowable range.

Since the inclination angles of the 1 st slope 105 and the 2 nd slope 104 are kept constant regardless of the temperature change, the holding device 100 can always maintain the position and the horizontal state of the object 101 constant even when the ambient temperature changes.

Fig. 3 and 4 show an example of a configuration for more reliably and smoothly sliding the support member 102 along the 1 st inclined surface 105 and the holding member 106 along the 2 nd inclined surface 104. Fig. 3 and 4 show the same state as fig. 1 (b). In fig. 3, the 1 st inclined surface 105 of the base member 103 is provided with the 1 st guide 31 extending in the direction in which the 1 st inclined surface 105 is inclined. Further, a 1 st sliding member 32 that is guided by the 1 st guide 31 and slides is provided on a surface of the support member 102 facing the 1 st inclined surface 105. In the example of fig. 3, the 2 nd guide 33 extending in the direction in which the 2 nd slope 104 inclines is disposed on the 2 nd slope 104 of the support member 102. Further, a 2 nd sliding member 34 that is guided by the 2 nd guide portion 33 to slide is provided on a surface of the holding member 106 facing the 2 nd inclined surface 104. In the example of fig. 3, the group of the 1 st guide portion 31 and the 1 st sliding member 32 and the group of the 2 nd guide portion 33 and the 2 nd sliding member 34 are provided, but only one of the groups may be provided.

The horizontal state of the object 101 is determined by, for example, the self weight of the object 101 and the holding member 106, the inclination angle of the 1 st slope 105, the inclination angle of the 2 nd slope 104, the slidability of the 1 st guide 31, and the slidability of the 2 nd guide 33. Therefore, the 1 st guide portion 31 and the 2 nd guide portion 33 may be members that have low friction and can be guided linearly. For example, as shown in fig. 3, linear guides may be used for the 1 st guide portion 31 and the 2 nd guide portion 33.

In addition, the arrangement relationship of the guide portion and the slide member may be reversed. For example, as shown in fig. 4, the 1 st sliding member 32 may be provided on the 1 st inclined surface 105 of the base member 103, and the 1 st guide 31 may be disposed on the surface of the support member 102 facing the 1 st inclined surface 105. In the example of fig. 4, the 1 st guide portion 31 and the 2 nd guide portion 33 are formed of V-shaped grooves, and the 1 st sliding member 32 and the 2 nd sliding member 34 are formed of spherical bodies. Alternatively, one may be constituted by a linear guide and the other may be constituted by a V-shaped groove or the like. In the configuration shown in fig. 4 in which the spherical body is disposed in the V-shaped groove, since the V-shaped groove receives the spherical body at 2 points, by providing the configuration in 3 places of the object 101, the degree of freedom can be restricted appropriately, and the object 101 can be held without transmitting strain thereto.

As described above, in the case where the thermal expansion of the support member 102 is a main factor affecting the position of the object 101 and the necessary accuracy of the horizontal state, the 1 st inclined surface 105 and the 2 nd inclined surface 104 may be made to have the same inclination angle. However, the thermal expansion of the holding member 106 and the base member 103 may affect the allowable range of the positional displacement of the object 101. In this case, the 1 st slope 105 and the 2 nd slope 104 may have different inclination angles in consideration of thermal expansion of the holding member 106 and the base member 103.

The following description will be made with reference to fig. 5(a) and 5 (b). For example, when a thermal load is applied to the apparatus, the allowable range of the positional displacement of the object 101 is affected by, for example, the following 3 thermal expansion actions. Fig. 5(a) shows a state where such an influence is not exerted.

(1) The support member 102 thermally expands in the horizontal direction and the gravitational direction (Z direction).

(2) A thermal load is applied to a portion of the base member 103 that holds the support member 102, and the portion thermally expands in the horizontal direction and the gravitational direction.

(3) The holding member 106 thermally expands in the direction of gravity.

As shown in fig. 5(b), the support member 102 is displaced in the antigravity direction by deforming upward along the 1 st inclined surface 105 of the base member 103 by the amount of thermal expansion in the horizontal direction of the base member 103 and the amount of thermal expansion in the horizontal direction of the support member 102. The object 101 is displaced in the anti-gravitational direction by the amounts of thermal expansion in the gravitational direction of the base member 103, thermal expansion in the gravitational direction of the support member 102, and thermal expansion in the gravitational direction of the holding member 106. The object 101 needs to be lowered in the direction of gravity by an amount by which the support member 102 is deformed upward along the 1 st inclined surface 105 of the base member 103 and is displaced, and by an amount by which the base member 103, the support member 102, and the holding member 106 are thermally expanded in the direction of gravity and are displaced. Therefore, the inclination angle of the 2 nd slope 104 is larger than that of the 1 st slope 105 by an amount that takes into account the amount of thermal expansion of the base member 103 in the horizontal direction and the amount of positional deviation of the base member 103, the support member 102, and the holding member 106 due to thermal expansion in the gravity direction.

Thus, the 1 st slope 105 and the 2 nd slope 104 may have different inclination angles. At this time, the angle difference between the 1 st slope 105 and the 2 nd slope 104 may be set based on the respective thermal expansion amounts of the holding member 106, the support member 102, and the base member 103. Accordingly, the object 101 can suppress positional displacement of the base member 103, the support member 102, and the holding member 106 due to thermal expansion within an allowable range, and as a result, the horizontal state of the object 101 can be maintained.

< embodiment 2 >

Next, an embodiment of an optical device using the holding device will be described. The optical device in this embodiment includes the optical element and the holding device described above, and the holding device holds the optical element as the object to be held.

Fig. 6 is a diagram showing a configuration of a light source device 400 as an example of an optical device in the present embodiment. The light source device 400 includes a light source 407 and a reflector as an optical element that reflects light from the light source 407 in a predetermined direction. In the present embodiment, the light source 407 may be a mercury lamp or a halogen lamp, for example. In addition, the reflector may include an elliptical reflector 401a and a spherical reflector 401 b.

The spherical mirror 401b is disposed so that a bright point between the electrodes of the light source 407 becomes the center of the reflecting spherical surface. The spherical reflector 401b reflects light from the light source 407 and returns to a bright point of the light source once, and then passes directly between the cathode electrode 409a and the anode electrode 409b and is guided to the elliptical reflector 401 a. The elliptical reflector 401a is disposed such that a bright point between the cathode electrode 409a and the anode electrode 409b of the light source 407 becomes a first focal point of the reflection elliptical surface. The elliptical reflector 401a condenses light from the light source 407 and light reflected from the spherical reflector 401b at the second focal point.

The elliptical reflector 401a and the spherical reflector 401b are held by the holding device 100, as shown in the drawing. In addition, the holding device 100 that holds the elliptical reflector 401a is provided on the driving mechanism 408. The driving mechanism 408 moves the elliptical reflector 401 in the direction of gravity via the holding device 100, thereby changing the degree of light collection at the second focal point.

By holding the spherical mirror 401b by the holding device 100, even if a heat load is applied from the light source 407, the positional displacement of the spherical mirror 401b can be suppressed within the allowable range. This allows the reflected light to pass through without contacting the cathode electrode 409a and the anode electrode 409 b.

Further, by holding the elliptical reflector 401a by the holding device 100, even if a heat load is applied from the light source 407, the positional displacement of the elliptical reflector 401a can be suppressed within the allowable range. This allows light from the light source 407 and light reflected by the spherical mirror 401b to be condensed at the second focal point with high accuracy.

While the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the idea of the present invention.

Description of the reference numerals

100: a holding device; 101: an object; 102: a support member; 103: a base member; 106: a holding member; 110: a structure.

Claims

1. A holding device for holding an object, characterized in that,

the holding device includes:

a structure surrounding the object;

a holding member that holds the object;

a base member provided on an inner wall of the structure; and

a support member that is mounted on the base member and supports the holding member,

a 1 st inclined surface is formed on a surface of the base member supporting the support member, the 1 st inclined surface having a height that is higher toward an outer side in a horizontal direction with respect to the object,

a 2 nd inclined surface is formed on a surface of the support member supporting the holding member, the 2 nd inclined surface having a height that is increased horizontally outward with respect to the object in a state where the support member is mounted on the 1 st inclined surface,

the support member is slidable along the 1 st inclined surface, the holding member is slidable along the 2 nd inclined surface,

the positional displacement of the object is maintained within an allowable range by sliding the support member and the holding member.

2. The holding device according to claim 1,

as the support member slides along the 1 st inclined surface, the holding member slides along the 2 nd inclined surface due to the weight of the holding member and the object, thereby maintaining the height of the object constant.

3. The holding device according to claim 2,

the support member slides along the 1 st inclined surface due to deformation caused by thermal expansion.

4. The holding device according to claim 1,

the holding member includes a plurality of holding members for holding the object at a plurality of positions,

the base member includes a plurality of base members for supporting the plurality of holding members via the support member,

the support member is an annular member surrounding the object.

5. The holding device according to claim 1,

the holding device further includes:

a 1 st guide portion, which is provided on the 1 st inclined surface of the base member, and extends in an inclined direction of the 1 st inclined surface; and

and a 1 st sliding member provided on a surface of the support member facing the 1 st inclined surface, the 1 st sliding member being guided by the 1 st guide portion to slide.

6. The holding device according to claim 1,

the holding device further includes:

a 2 nd guide portion provided on the 2 nd inclined surface of the support member and extending in an inclined direction of the 2 nd inclined surface; and

and a 2 nd sliding member provided on a surface of the holding member facing the 2 nd inclined surface, the 2 nd sliding member being guided by the 2 nd guide portion to slide.

7. The holding device according to claim 1,

the 1 st inclined plane and the 2 nd inclined plane have the same inclination angle.

8. The holding device according to claim 1,

the 1 st slope and the 2 nd slope have different inclination angles, and an angle difference between the 1 st slope and the 2 nd slope is set based on respective thermal expansion amounts of the holding member, the support member, and the base member.

9. An optical device, characterized in that,

the optical device includes:

an optical element; and

the holding device according to any one of claims 1 to 8,

the holding device holds the optical element as the object.

10. The optical device of claim 9,

the optical device is a light source device having a light source and a reflector for reflecting light from the light source in a predetermined direction,

the holding device holds the reflector as the optical element.