JPH06250061A - Optical member holding device - Google Patents

Abstract

(57) [Abstract] [Purpose] The optical axis stability of the mirror is improved, the structure is simplified, and adjustment of the holding force is not required. [Constitution] Since the horizontal mirror 1 is held in a suspended state, the longitudinal direction of the leaf spring 6 and the direction of gravity coincide with each other, and buckling or twisting of the leaf spring 6 is unlikely to occur.
Stability in the optical axis direction of is increased. Moreover, since the holding force is not adjusted by the adjusting mechanism, the structure is simple and the holding force need not be adjusted. Further, the leaf spring 6 has a hole 9 for temporary fastening.
Since the adhesive 8 is injected into the temporary fixing hole 9 to temporarily fix the leaf spring 6 to the frame body 3 after the adhesive 8 is cured, the leaf spring 6 is fixed to the frame body 3 with the bolt 10. The leaf springs 6 that can be fixed and that result when the bolt 10 is tightened
Can be prevented, and the stability of the horizontal mirror 1 in the optical axis direction can be further improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical member holding device, and more particularly to an optical member holding device for a projection optical system such as an exposure apparatus for semiconductor manufacturing.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view of a conventional optical member holding device. This optical member holding device holds a disk-shaped horizontal mirror 101 having a vertical optical axis. As shown in FIG. 6, a collar portion 105 is provided on the inner peripheral surface of a cylindrical frame body 102, and A step portion 106 is provided on the inner peripheral surface of the collar portion 105. The step portion 106 of the collar portion 105 is formed by the horizontal mirror 10.
The horizontal mirror 101 is supported by receiving the peripheral edge portion of 1. That is, the lower surface 101 a of the horizontal mirror 101 has the step portion 106.
It is supported by a horizontal surface 106a of

Further, as a holding device for a large mirror or a mirror requiring high accuracy, the lower surface and side surfaces of a horizontal mirror are held at a plurality of points and can be adjusted in three axial directions so as to achieve an ideal weight distribution. Some are equipped with an adjustment mechanism.

Further, as a holding device using a leaf spring,
There is also one in which a leaf spring is bridged from the frame body to the horizontal mirror along the tangential direction of the horizontal mirror.

[0005]

However, in the conventional optical member holding device that holds the peripheral portion of the horizontal mirror over the entire circumference thereof, the lower surface 101 of the horizontal mirror 101 that contacts each other.
The flatness between a and the horizontal surface 106a of the stepped portion 106 must be strictly controlled, and if a predetermined flatness cannot be obtained, the mirror surface is distorted due to the influence of the undulations of the mutually contacting surfaces. There was a problem of easy occurrence.

Further, the conventional optical member holding device for holding the lower surface and the side surface of the horizontal mirror at a plurality of points has a problem that the adjusting mechanism is complicated and it is difficult to adjust the holding force at each holding point.

Further, in a holding device using a leaf spring, when the leaf spring is fixed to the side surface of the horizontal mirror with a bolt, the leaf spring may be slightly moved when the bolt is tightened, or buckling or twisting may occur. However, there is a problem that the optical axis of the horizontal mirror is not stable.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical member holding device that has a small strain applied to an optical member, has a simple structure, and does not require adjustment of holding force. .

[0009]

In order to solve the above-mentioned problems, an optical member holding device according to a first aspect of the present invention comprises a cylindrical frame for accommodating a disk-shaped optical member having a vertical optical axis, and At least three support members arranged at equal intervals along the circumferential direction in the frame and supporting the optical member are provided, and the support members are suspended in the frame along the vertical optical axis. And a block that is connected to the lower portion of the leaf spring and supports the optical member.

Further, in the optical member holding device according to the second aspect of the present invention, the leaf spring is provided with a temporary fastening hole for temporarily fastening the leaf spring to the frame body with an adhesive.

[0011]

Since the optical member is held in a suspended state, and the longitudinal direction of the leaf spring and the direction of gravity coincide with each other, buckling and twisting of the leaf spring do not easily occur, and the stability of the optical member in the optical axis direction is improved. Increase.

If the plate spring is provided with a temporary fixing hole, an adhesive is injected into the temporary fixing hole to temporarily fix the plate spring to the frame body, and after the adhesive is hardened, the plate spring is bolted. Can be fixed to the frame, and it is possible to prevent fine movement of the leaf spring that occurs when the bolt is tightened.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a fragmentary sectional view of an optical member holding device according to an embodiment of the present invention, and FIG. 2 is a plan view of the optical member holding device of FIG.

A disk-shaped horizontal mirror 1 having a vertical optical axis is supported by six supporting members 2a to 2f, and the supporting members 2a to 2f are supported.
The 2f are arranged in the cylindrical frame body 3 at equal intervals along the circumferential direction.

A convex portion 4 is provided on the side surface of the horizontal mirror 1 along the circumferential direction. The upper surface and the lower surface of the convex portion 4 are formed in a tapered shape.

A collar portion 5 is provided on the inner peripheral surface of the frame 3 along the circumferential direction. Two female screws (not shown) are provided on the inner peripheral surface of the collar portion 5 at regular intervals.

The supporting members 2a to 2f are connected to a leaf spring 6 mounted on the frame body 3 so as to hang down (suspend) along the vertical optical axis, and a lower portion of the leaf spring 6, and the horizontal mirror 1
It is composed of a convex portion 4 and a block 7 which is fitted.

At one end of the leaf spring 6, a temporary fastening hole 9 (see FIG. 3) for injecting an adhesive 8 for temporary fastening and two through holes (not shown) for passing the bolt 10 are provided. ) And are provided. The other end of the leaf spring 6 is provided with two through holes (not shown) for passing the bolt 11.

A convex portion 7a for receiving the lower surface of the convex portion 4 of the horizontal mirror 1 is provided below the block 7, and the upper surface of the convex portion 7a is formed in a tapered shape. A leaf spring 12 is attached to the upper portion of the block 7 with a bolt 13. The end of the leaf spring 12 bends and contacts the upper surface of the convex portion 4 of the horizontal mirror 1, and the leaf spring 12 and the convex portion 7a of the block 7 sandwich and hold the convex portion 4 of the horizontal mirror 1 from above and below.

Next, a method of holding the horizontal mirror 1 using this optical member holding device will be described.

First, the leaf spring 6 is connected to the block 7.
To connect the leaf spring 6 to the block 7, the bolt 11 is screwed into the female screw of the block 7 through the through hole of the leaf spring 6.

Next, the convex portion 4 of the horizontal mirror 1 is attached to the leaf spring 12.
And the convex portion 7a of the block 7 from above and below, and the bolt 13 is tightened. Since the upper surface and the lower surface of the convex portion 4 of the horizontal mirror 1 are tapered, the clamping force is small, and the strain given to the horizontal mirror 1 is also small.

After that, the horizontal mirror 1 placed in the frame body 3
Is placed on a tool holder (not shown) to maintain a state where there is no distortion (ideally floating in the space), and in this state, one end of the leaf spring 6 is attached to the inner peripheral surface of the flange portion 5 of the frame body 3. Temporarily fasten to. For temporary fixing, as shown in FIG. 3, an adhesive 8 such as epoxy is injected into the hole 9 for temporary fixing of the leaf spring 6.
Since the adhesive 8 is injected into the temporary fixing hole 9 and temporarily fixed, the distortion in the optical axis direction due to the curing shrinkage of the adhesive 8 hardly occurs. The stability in the eccentric direction is maintained by the rigidity of the leaf spring 6 in the width (W) direction. On the contrary, since the leaf spring 6 has low rigidity in the thickness (T) direction, it is possible to absorb a dimensional change due to a difference in linear expansion coefficient between the horizontal mirror 1 and the frame body 3 when the temperature changes. Also, during assembly, the horizontal mirror 1 and the frame 3
It is possible to absorb the error in the radial direction between and.

Finally, after the adhesive 8 has hardened, the bolt 1
0 is screwed into the female screw of the flange portion 5 of the frame body 3 from the through hole of the leaf spring 6.

According to the optical member holding device of this embodiment,
Since the horizontal mirror 1 is held in a suspended state, and the longitudinal direction of the leaf spring 6 coincides with the direction of gravity, buckling or twisting of the leaf spring 6 is unlikely to occur, and the horizontal mirror 1 is stable in the optical axis direction. Becomes higher. Moreover, since the lower surface and the side surface of the horizontal mirror 1 are not held at a plurality of points, the structure is simple and adjustment of the holding force is unnecessary.

Since the leaf spring 6 is provided with the temporary fastening hole 9, the adhesive 8 is injected into the temporary fastening hole 9 to temporarily fasten the leaf spring 6 to the frame 3 and the adhesive 8 is removed. After hardening, the leaf spring 6 can be fixed to the frame body 3 with the bolt 10, and as a result, the fine movement of the leaf spring 6 that occurs when the bolt 10 is tightened can be prevented, and the stability of the horizontal mirror 1 in the optical axis direction can be improved. It can be further improved.

FIG. 4 is a sectional view of an optical member holding device according to another embodiment of the present invention, and FIG. 5 is a plan view of the optical member holding device of FIG. The same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the above-described embodiment, the temporary fixing hole 9 is provided at one end of the plate spring 6, and the adhesive 8 is injected into the temporary fixing hole 9 to temporarily fix the plate spring 6 to the frame body 3 and bond it. Although the leaf spring 6 is fixed to the frame body 3 by the bolt 10 after the agent 8 is hardened, instead of this, as shown in FIGS.
Adhesive groove 2 into which the adhesive 18 is injected on the upper surface of the brim portion 15
0 and the through hole 2 that allows one end of the leaf spring 16 to escape to the adhesive groove 20.
1 and 1 are provided above and below along the optical axis direction, and one end of the leaf spring 16 is inserted into the adhesive groove 20 from the through hole 21.
The leaf spring 16 may be fixed to the frame body 23 by injecting the adhesive 18 therein. In the above embodiment, the leaf spring 16
Although the bolt 10 for fixing the adhesive is not used, the adhesive groove 20 for accommodating a large amount of the adhesive 18 is provided, so that the adhesive portion can have sufficient strength. According to the optical member holding device of this embodiment, the horizontal mirror 1 can be held in a suspended state by a simpler structure.

Although the horizontal mirror 1 is held by using the six supporting members 2a to 2f in the above embodiment, at least three supporting members may be used, and the number of supporting members increases. The influence on the horizontal mirror 1 can be reduced.

Further, in the above-described embodiment, the convex portion 4 is provided on the side surface of the horizontal mirror 1 so as to sandwich the convex portion 4, but instead of this, the side surface of the horizontal mirror 1 is arranged along the circumferential direction. The convex portion 4 may not be provided, and the peripheral portion of the horizontal mirror 1 may be sandwiched.

Further, although the upper surface and the lower surface of the convex portion 4 of the horizontal mirror 1 are tapered, both surfaces may be parallel planes.

Further, in each of the above-mentioned embodiments, the case where the invention is applied to the horizontal mirror 1 of the optical member has been described, but the invention can be applied to a lens instead of the mirror.

[0034]

As described above, according to the optical member holding device of the present invention, the optical member is held in a suspended state, and the longitudinal direction of the leaf spring and the direction of gravity coincide with each other. Buckling and twisting are less likely to occur, and the stability of the optical member in the optical axis direction is high. Further, the structure is simple, and it is not necessary to adjust the holding force of the optical member by the adjusting mechanism.

If the leaf spring is provided with a temporary fastening hole, an adhesive is injected into the temporary fastening hole to temporarily fasten the leaf spring to the frame body, and after the adhesive is hardened, the leaf spring is bolted. Can be fixed to the frame body, and as a result, it is possible to prevent fine movement of the leaf spring that occurs during bolt tightening, and to further improve the stability of the optical member in the optical axis direction.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical member holding device according to an embodiment of the present invention.

FIG. 2 is a plan view of the optical member holding device of FIG.

FIG. 3 is an enlarged cross-sectional view of a part of the optical member holding device of FIG.

FIG. 4 is a cross-sectional view of an optical member holding device according to another embodiment of the present invention.

FIG. 5 is a plan view of the optical member holding device of FIG.

FIG. 6 is a sectional view of a conventional optical member holding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Horizontal mirror 2a-2f Support member 3 Frame 6 Leaf spring 7 Block 8 Adhesive 9 Hole for temporary fastening

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 21/027

Claims (2)

[Claims] 1. A cylindrical frame body for accommodating a disk-shaped optical member having a vertical optical axis, and arranged in the frame body at equal intervals along a circumferential direction,
At least three supporting members for supporting the optical member, wherein the supporting member is connected to a leaf spring suspended along the vertical optical axis in the frame, and a lower portion of the leaf spring, An optical member holding device comprising: a block supporting an optical member. 2. The optical member holding device according to claim 1, wherein the leaf spring is provided with a temporary fastening hole for temporarily fastening the leaf spring to the frame body with an adhesive.