JP2003140015A - Sealing structure for cylinder body, device provided with it, optical element holding structure, and exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely seal a part between contact parts of annular members constituting a cylinder body. SOLUTION: With respect to a sealing structure for a cylinder body formed by bringing end faces in the axial direction of a first annular member 4 and a second annular member 5 into contact with each other, slopes 4a and 5a oppositely inclined to the axial direction are formed in the outer peripheries of contact parts of both annular members, and an annular elastic member 12 is brought into contact with both slopes. A first annular pressing member 13 having an inner peripheral surface 13a which is inclined in the axial direction so as to approximately face the slope of the second annular member and is brought into contact with the elastic member and a second annular pressing member 14 having an inner peripheral surface 14a which is inclined in the axial direction so as to approximately face the slope of the first annular member and is brought into contact with the elastic member are arranged on the outer peripheral side of the elastic member, and a displacement giving means 15 is provided which displaces the first and second pressing members to relatively approximate them to each other in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure of a cylindrical body formed by contacting axial end faces of a plurality of annular members, and particularly to a cylinder for holding optical elements such as lenses and mirrors in an optical device. The present invention relates to a seal structure suitable for sealing an internal space of a body.

[0002]

2. Description of the Related Art In an exposure apparatus for manufacturing a semiconductor integrated circuit, a projection optical system is used when an original pattern is exposed and transferred onto a substrate at a predetermined magnification by illumination light emitted from a light source. In particular, in recent years, with the miniaturization of patterns, the exposure wavelength has been reduced to a single wavelength.
A nm ArF excimer laser, a 157 nm F2 excimer laser, or the like is used.

In the exposure light of the ArF excimer laser, the F2 excimer laser, etc., the emission spectrum thereof overlaps with the absorption spectrum of oxygen, so that the light transmittance decreases due to the absorption of oxygen, which leads to the deterioration of the performance of the projection exposure apparatus.

Therefore, in a projection exposure apparatus using exposure light such as ArF excimer laser or F2 excimer laser, a technique of replacing the atmosphere in the exposure light path with a gas (nitrogen gas, helium gas, etc.) which is inert to the photochemical reaction. Is used.

In the projection optical system of such an exposure apparatus, several optical elements are held by respective holding members, and these holding members are arranged in the optical axis direction of the optical elements. .

In order to prevent the inflow of the atmosphere between the holding members by supplying an inert gas into these holding members, Japanese Patent Laid-Open No. 11-233412 discloses an upper lens barrel and a lower lens barrel. Providing a seal structure between the members of the above, these seal parts are the groove of the lower ring, the upper ring inserted into this groove, and the seal structure such as inert grease filled between these grooves and the upper ring. There is.

As another configuration, a rubber tubular member may be provided on the outer peripheral surface side of the flange at the upper end of the lower barrel and the flange at the lower end of the upper barrel to prevent the inflow of air. Proposed.

Further, as a conventional seal structure, there is a seal structure in which an elastic material is sandwiched between holding members for holding several optical elements. This seal structure will be described with reference to FIG.

In this figure, the direction of gravity coincides with the optical axis direction and is the -Z direction in the figure. 61 is the first optical element,
62 is a second optical element, 63 is a first cell member for holding the first optical element 61, and 64 is a second optical element 6.
2 is a second cell member for holding 2.

Reference numeral 65 is a first lens barrel member for accommodating and holding the first cell member 63, and 66 is a second cell member 6.
4 is a second lens barrel member for housing and holding 4.

Further, 67 is the first and second lens barrel members 6
O-ring, which is an elastic material sandwiched between 5, 66, 6
8 is a bonding material, 69 is the first and second lens barrel members 65, 6
6 is a bolt for fastening 6, and 70 is each cell member 63, 6
4 is a holding ring for pressing the lens barrel 4 onto each of the lens barrel members 65 and 66 for positioning in the optical axis direction.

The first optical element 61 comprises the first cell member 6
The bonding material 6 which is disposed on the inner periphery of the third member 3 and is injected between the outer peripheral surface of the first optical element 61 and the inner peripheral surface of the first cell member 63.
It is joined to the first cell member 63 by 8.

The first cell member 63 is the first lens barrel member 6
It is fitted in the ring 5 and positioned in the radial direction, and is positioned in the optical axis direction by the holding ring 70. In addition, similarly, the second optical element 62 includes the second cell member 6
4 is used for holding, and is joined by the joining material 68. Second
The cell member 64 is fitted in the second lens barrel member 66 to be positioned in the radial direction, and is positioned in the optical axis direction by the holding ring 70.

An O-ring 67 is sandwiched between the first lens barrel member 65 and the second lens barrel member 66 so that the optical axes of the first optical element 61 and the second optical element 62 coincide with each other. Then, the lens barrel members 65 and 66 are fastened with bolts 69 while they are positioned.

[0015]

However, in the seal structure proposed in Japanese Patent Laid-Open No. 11-233412, a new seal structure is provided between the upper lens barrel and the lower lens barrel forming the lens barrel. Space is needed.

When a rubber tubular member is provided, the rubber tubular member is fully encircled by a desired force near the flange at the upper end of the lower lens barrel and near the flange at the lower end of the upper lens barrel. It is difficult to prevent the inflow of air without pressing it all over.

Further, as shown in FIG. 5, the lens barrel member 6
When the O-ring 67 is sandwiched between 5 and 66 for sealing, before the two lens barrel members 65 and 66 are firmly fastened by the bolts 69, the optical elements holding the lens barrel members 65 and 66 are held together. Although it is necessary to adjust the positions so that the optical axes coincide with each other, the lens barrel members 65 and 66 are crushed by the sandwiching force and the friction generated between the O ring 67 and the lens barrel members 65 and 66 causes the lens barrel members. There is a problem that it becomes difficult to perform positioning between 65 and 66 with high accuracy.

Although it is possible to first adjust the optical axis positions of both lens barrel members 65 and 66 and then clamp the O-ring 67 by bolts, the O-ring 67 is crushed when the bolts are fastened. At this time, the elastic force generated in the O-ring 67 may cause both the lens barrel members 65 and 66 to shift in an unexpected direction.

[0019]

In order to solve the above-mentioned problems, according to the present invention, a cylinder formed by contacting axial end faces of a first annular member and a second annular member with each other. In the body seal structure, an inclined surface (for example, an inclination that forms a groove having a V-shaped cross section that opens outward in the radial direction) is formed on the outer periphery of the contact portion of both annular members, the inclinations being opposite to each other in the axial direction. Surface) is formed, and an annular elastic member is brought into contact with both of these inclined surfaces. Then, on the outer peripheral side of the elastic member, an annular first pressing member having an inner peripheral surface that is inclined with respect to the axial direction so as to substantially face the inclined surface of the second annular member and has contact with the elastic member; An annular second pressing member having an inner peripheral surface which is inclined with respect to the axial direction and has contact with the elastic member is disposed so as to be substantially opposed to the inclined surface of the annular member, and the first and second pressing members are connected to the shaft. Displacement imparting means for displacing in a direction relatively approaching the direction is provided.

That is, by displacing the first and second pressing members in the axially relatively approaching direction by the displacement imparting means, the elastic member is surely pressed against the inclined surfaces of both annular members. There is. Further, since the two annular members that have been axially aligned are fastened with bolts or the like and then the elastic member may be arranged on the outer periphery thereof, the elastic members do not hinder the axial alignment of the two annular members.

Moreover, the first and second displacement applying means
Even if a uniform displacement force is not applied over the entire circumference of the pressing member, a uniform pressing force acts on the elastic member from the first and second pressing members over the entire circumference. It is possible to reliably seal over.

As the displacement imparting means, there are two displacement means that are inclined with respect to the axial direction so as to substantially face the inclined surfaces of the second and first annular members, which contact the outer circumferences of the first and second pressing members, respectively. A substantially annular tightening member having an inner peripheral surface and generating a tightening force inward in the radial direction may be used. Alternatively, a bolt mounted between the first and second pressing members may be used.

When a fastening member such as a bolt for fastening the first annular member and the second annular member is provided, the sealing structure is provided outside the fastening member in the radial direction of the cylindrical body. Is good.

According to the seal structure of the present invention, for example, when the optical element is held inside the cylindrical body, the outside air flows into the inner space of the cylindrical body, and further, the laser caused by the outside air (oxygen or the like) flowing in. It becomes possible to prevent absorption of light and the like. It is also possible to reliably prevent outflow of the inert gas or the like from the inner space of the cylindrical body.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 (a),
FIG. 1B shows the lens barrel (optical element holding structure) 50 according to the first embodiment of the present invention. In this figure, the direction of gravity coincides with the optical axis and is the -Z direction in the figure.
Further, FIG. 2 shows an enlarged seal structure in the lens barrel.

Reference numerals 1 to 3 are first to third optical elements, and 4 is a first annular member for holding the outer peripheral portion of the first optical element 1.
The cell member 5 is a second member for holding the outer peripheral portion of the second optical element 2.
A second cell member serving as an annular member, and 6 is a third cell member that holds the outer peripheral portion of the third optical element 3.

The contact between the peripheral portion of the lower surface of the first optical element 1 and the inner peripheral step portion of the first cell member 4 causes the first optical element 1 to move to the first position.
Positioning in the optical axis direction with respect to the cell member 4 is performed, and the second
By abutting the lower surface peripheral portion of the optical element 2 and the inner peripheral stepped portion of the second cell member 5, the positioning of the second optical element 2 with respect to the second cell member 5 in the optical axis direction is performed.

Then, the outer peripheral portion of the first optical element 1 and the inner peripheral portion of the first cell member 4, the outer peripheral portion of the second optical element 2 and the inner peripheral portion of the second cell member 5, and the outer peripheral portion of the third optical element 3. The portion and the inner peripheral portion of the third cell member 6 are joined with a joining material 7.

The first optical element 1 and the first cell member 3 joined by the joining material 7 constitute a first barrel unit. Similarly, the second optical element 2 and the second cell member 4
The second barrel unit is configured by, and the third barrel unit is configured by the third optical element 3 and the third cell member 5.

As the first to third optical elements 1 to 3, lenses, parallel plate glasses, mirrors, prisms, binary optics, etc. are used. Also, first to
As a material for the third cell members 4 to 6, a copper alloy such as brass, stainless steel, iron, Invar of a low thermal expansion metal, a metal such as carbon steel, ceramics, or the like is used. Further, as the bonding material 7, a low melting point metal, an adhesive, a welding material or the like is used.

These lens barrel units are arranged so that the end faces in the optical axis direction of the flange portions of the first to third cell members 4 to 5 come into contact with each other (that is, the first to third optical elements 1 to 3). Arranged in the optical axis direction of the) first to third optical elements 1
After the positioning in the radial direction is performed so that the optical axes of 3 to 3 coincide with each other, both flange portions are fastened by the plurality of first bolts 8 arranged at equal intervals in the circumferential direction.

First to third parts fastened by the first bolt 8
The cell members 3 to 5 form a lens barrel main body as a cylindrical body. The upper opening and the lower opening of this lens barrel body are sealed by the first and third optical elements 1 and 3, respectively. Therefore, in the lens barrel body,
A sealed space surrounded by the lens barrel body and the first and third optical elements 1 and 3 is formed.

A vent hole AA is formed on the outer peripheral side of the lens holding portion of the second cell member 5 so as to connect the upper and lower spaces in the lens barrel main body which is partitioned by the second optical element 2. ing.

An O-ring 20 is arranged between the bottom surface of the head of the first bolt 8 and the periphery of the bolt hole of the first cell member 7, and the space inside the lens barrel body through the bolt hole. It prevents the inflow of outside air into the.

The lens barrel 50 produced as described above
Is used in a projection optical system of, for example, the exposure apparatus shown in FIG. 4 (this apparatus will be described later), a gas inert to the photochemical reaction is passed through the gas supply port 9 formed in the third cell member 6 to the lens. The lens barrel 50 is supplied into the lens barrel 50, and the lens barrel 50 is purged through the vent hole AA and the discharge port 10 formed in the second cell member 5.

Second in the flange portion of the first cell member 4
A surface (contact portion) in contact with the upper end surface of the flange portion of the cell member 5
A first chamfered portion (inclined surface) 4a is formed on the outer periphery of the first chamfered portion 4a so that the outer peripheral side faces upward with respect to the optical axis direction. In addition, the outer periphery of the surface of the flange portion of the second cell member 5 in contact with the lower end surface of the flange portion of the first cell member 4 (contact portion) is inclined so that the outer peripheral side is downward with respect to the optical axis direction. Two chamfered portions (inclined surfaces) 5a are formed.
The first and second chamfered portions 4a and 5a form a groove having a lateral V-shaped cross section that is open outward in the radial direction.

Further, the first and second chamfered portions 4a, 5a
An O-ring 12 which is an elastic member is mounted in the V-shaped groove formed by, and the inner peripheral portion of the O-ring 12 contacts the first and second chamfered portions 4a and 5a over the entire circumference thereof. As a material for the O-ring 12, fluororubber or the like is used.

Further, the first portion is provided on the upper side of the outer circumference of the O-ring 12.
The pressing ring 13 and the second pressing ring 14 are arranged below the outer circumference. Both the inner peripheral surface 13a and the outer peripheral surface 13b of the first pressing ring 13 are inclined surfaces that substantially face the second chamfered portion 5a. Further, both the inner peripheral surface 14a and the outer peripheral surface 14b of the second pressing ring 14 are inclined surfaces that substantially face the first chamfered portion 4a.

In this embodiment, the inner peripheral surfaces 14a, 14a and the outer peripheral surfaces 13b, 14b of the first and second pressing rings 13, 14 are substantially parallel to the second and first chamfered portions 5a, 4a, respectively. It is a slope. However, the inner and outer peripheral surfaces of these chamfered portions 5a, 4a need only be inclined surfaces that are substantially opposed to the second and first chamfered portions 5a, 4a.
It need not be substantially parallel to a. Further, the inclination angles of these inner and outer peripheral surfaces may be different.

Further, the first and second pressing rings 13,
A coupling member (displacement imparting means) is provided on the outer peripheral side of 14.
15 are arranged. The coupling member 15 has a substantially annular shape in which one ends of two arc-shaped members are rotatably connected by a connecting plate 17 and the other ends of these two arc-shaped members are connected by a second bolt 16. Has been done. When the second bolt 16 is tightened, the two arc-shaped members of the coupling member 15 rotate inward about the connection position with the connecting plate 17. As a result, the radial dimension of the coupling member 15 is reduced, and a radially inward tightening force is generated.

When the coupling member 15 is tightened in the radial direction (when the tightening force F in FIG. 2 acts), the inner peripheral surfaces 15a and 15b of the coupling member 15 are inclined surfaces as described above. , The first pressing ring 13 and the second pressing ring 14 are displaced in a direction in which they are relatively close to each other (up and down in the optical axis direction).

Therefore, the inner peripheral surface 1 of the first pressing ring 13 is
3a crushes the outer peripheral upper side of the O-ring 12 toward the inner peripheral lower side, and the inner peripheral surface 14a of the second pressing ring 14 crushes the outer peripheral lower side of the O ring 12 toward the inner peripheral upper side. Therefore, the upper and lower portions of the inner circumference of the O-ring 12 are strongly pressed by the first chamfered portion 4a and the second chamfered portion 5a to be in a completely sealed state.

Here, as described above, the coupling member 15 has a portion of the coupling member 17 and a portion which are connected to each other via the bolt 16 in a state of being separated from each other to some extent. It is a portion where the tightening force is not applied to the first and second pressing rings 13 and 14.

However, in the present embodiment, since the ring-shaped first and second pressing rings 13 and 14 having no gap are interposed between the coupling member 15 and the O-ring 12, the O-ring 12 is provided. A force that presses the first and second chamfered portions 4a and 5a acts on the entire circumference of the. Therefore, the first and second chamfered portions 4a and 5a can be completely sealed over the entire circumference thereof.

Incidentally, the first and second chamfered portions 4a, 5
a, the inclination angle of each inclined surface formed on the first and second pressing rings 13, 14 and the coupling member 15, and the second
By controlling the tightening torque of the bolt 16, the surface pressure for pressing the O-ring 12 against the first and second chamfered portions 4a and 5a can be controlled.

In this embodiment, the first to third optical elements 1 to
3 for adjusting the optical axes, the outer peripheral surfaces of the first optical element 1 and the first cell member 4, the outer peripheral surfaces of the second optical element 2 and the second cell member 5, the third optical element 3 and the third cell member 6. Of the outer peripheral surface of each of the first to third cell members 4 to 4 are installed with desired concentricity.
The optical axes of the first to third optical elements 1 to 3 are adjusted with the outer peripheral surface of 6 as a reference to position each lens barrel unit at a desired position with high accuracy, and the first bolt 8 to the first to third cells. Member 4
Conclude ~ 6.

After that, the O-ring 12 is attached to the first chamfered portion 4a and the second chamfered portion 5 by using the seal structure of this embodiment.
It is a procedure for pressing and sealing b and b with a uniform force over the entire circumference.

Therefore, compared with the conventional case where the optical axis adjustment is performed with the O-ring sandwiched between the lens barrel units, the time spent for positioning the first to third lens barrel units can be shortened. In addition to this, the lens barrel 50 can be sealed with a simple structure.

(Second Embodiment) FIGS. 3A and 3B show a lens barrel (optical element holding structure) 150 according to a second embodiment of the present invention. In this figure, the direction of gravity coincides with the optical axis and is the -Z direction in the figure. Note that FIG. 3B is a sectional view taken along the line aa in FIG. 3A, which is a plan view from the optical axis direction. Further, FIG. 4 shows an enlarged seal structure in the lens barrel.

In this embodiment, 121 to 124 are first to fourth optical elements, and 125 to 128 are optical elements 121.
To 124 are first to fourth cell members. Vent holes AA are provided in each of them.

129 is the first and second cell members 125,
First lens barrel member (first annular member) for housing 126
And 130 is the third and fourth cell members 127, 12
Second lens barrel member (first annular member) for housing 8
Reference numeral 31 is a first spacer for adjusting the distance between the first optical element 121 and the second optical element 122, and 132 is a second spacer for adjusting the distance between the third optical element 123 and the fourth optical element 124. Further, 133 is the second optical element 122.
And a third spacer (second annular member) for adjusting the distance between the third optical element 123.

By abutting the lower surface peripheral portion of the first optical element 121 and the inner peripheral stepped portion of the first cell member 125, the first optical element 121 is positioned with respect to the first cell member 125 in the optical axis direction. The contact between the lower surface peripheral portion of the second optical element 122 and the inner peripheral step portion of the second cell member 126 positions the second optical element 122 with respect to the first cell member 126 in the optical axis direction.

The contact between the peripheral portion of the lower surface of the third optical element 123 and the inner peripheral stepped portion of the third cell member 127 positions the third optical element 123 with respect to the third cell member 127 in the optical axis direction. The contact between the peripheral portion of the lower surface of the fourth optical element 124 and the inner peripheral step of the fourth cell member 128 positions the fourth optical element 124 with respect to the fourth cell member 128 in the optical axis direction.

Then, the outer peripheral portion of the first optical element 121 and the inner peripheral portion of the first cell member 125, the outer peripheral portion of the second optical element 122 and the inner peripheral portion of the second cell member 126, and the third optical element 123.
The outer peripheral portion of the third cell member 127 and the outer peripheral portion of the fourth optical element 124 and the inner peripheral portion of the fourth cell member 128 are bonded with a bonding material 107.

The second cell member 126 holding the second optical element 122, the first spacer 131, and the first optical element 121 are provided on the stepped portion formed in the lower inner circumference of the first barrel member 129.
The first cell member 125 holding the above is stacked in this order, and the upper surface of the first cell member 125 has a first lens barrel member 129.
It is pressed down by a pressing ring 134 screwed onto the upper part of the inner circumference of the. As a result, the first lens barrel member 129 is moved to the first
The second cell members 125 and 126 (that is, the first and second optical elements 121 and 122) are positioned in the optical axis direction.

On the other hand, the fourth cell member 128 holding the fourth optical element 124, the second spacer 132, and the third optical element 123 are provided on the stepped portion formed in the lower inner circumference of the second lens barrel member 130. The held third cell members 127 are sequentially stacked on top of each other, and the upper surface of the third cell members 127 is pressed down by the pressing ring 134 screwed onto the upper inner circumference of the second barrel member 130. As a result, the third and fourth cell members 127 and 128 (that is, the third and fourth optical elements 123 and 124) are positioned with respect to the second barrel member 130 in the optical axis direction.

Then, the first and second lens barrel members 129, which accommodate the optical element and the cell member, respectively, are
130 is overlapped so that the optical axis direction end surfaces of the flange portions of the first and second lens barrel members 129 and 130 contact the optical axis direction end surfaces of the third spacer 133 sandwiched therebetween, and the first to fourth optical elements After the elements 121 to 124 are positioned in the radial direction so that the optical axes thereof coincide with each other, both flange portions and the third spacer 133 are fastened by a plurality of first bolts 108 that are evenly arranged in the circumferential direction.

The first and second lens barrel members 129 and 130 fastened by the first bolt 108 constitute a lens barrel main body as a cylindrical body. The upper opening and the lower opening of the lens barrel body are sealed by the first and fourth optical elements 121 and 124, respectively. Therefore, the lens barrel main body and the first
And a sealed space surrounded by the fourth optical elements 121 and 124 is formed.

The lens barrel 150 configured as described above
Is used in the projection optical system of, for example, the exposure apparatus shown in FIG. 4 (this apparatus will be described later), the fourth cell member 12
The gas inert to the photochemical reaction is introduced into the space inside the lens barrel main body through the gas supply port 109 formed on the outer peripheral side of the lens holding portion in FIG. Vents AA and first formed in the
The lens barrel 150 is purged through the gas outlet 110 formed on the outer peripheral side of the lens holding portion of the cell member 125.

The outer periphery of the surface (contact portion) of the flange portion of the first lens barrel member 129 which is in contact with the upper end surface of the third spacer 133 is inclined by the first chamfer so that the outer peripheral side faces upward with respect to the optical axis direction. The portion (inclined surface) 129a is formed. The first barrel member 1 in the third spacer 133 is also included.
A second chamfered portion (inclined surface) 133a is formed on the outer periphery of the surface (contact portion) of the flange portion 29 that contacts the lower end surface of the flange portion 29 so that the outer peripheral side is downward with respect to the optical axis direction.
The first and second chamfered portions 129a and 133a form a groove having a lateral V-shaped cross section that is open outward in the radial direction.

The outer periphery of the surface (contact portion) of the flange portion of the second lens barrel member 130 which contacts the lower end surface of the third spacer 133 is inclined so that the outer peripheral side is downward with respect to the optical axis direction. A three-chamfered portion (inclined surface) 130a is formed. Further, a surface (contact portion) in contact with the upper end surface of the flange portion of the second barrel member 130 in the third spacer 133.
A fourth chamfered portion (inclined surface) 133b is formed on the outer periphery of the so that the outer peripheral side is inclined upward with respect to the optical axis direction. These third and fourth chamfered portions 130a, 133
b forms a groove having a lateral V-shaped cross section that opens radially outward.

First and second chamfers 129a, 133
An O-ring 112a, which is an elastic member, is mounted in the V-shaped groove formed by a, and the inner peripheral portion of the O-ring 112a contacts the first and second chamfered portions 129a and 133a over the entire circumference. .

Further, the third and fourth chamfered portions 130a,
The O-ring 112b, which is an elastic member, is also mounted in the V-shaped groove formed by the 133b, and the inner peripheral portion of the O-ring 112b contacts the third and fourth chamfered portions 130a and 133b over the entire circumference. . In addition, O-ring 1
As the material of 12a and 112b, fluororubber or the like is used.

Further, a first pressing ring 137 is arranged above the outer circumference of the O-ring 112a, and a second pressing ring 138 is arranged below the outer circumference thereof. Inner peripheral surface 1 of the first pressing ring 137
37a is an inclined surface that substantially faces the second chamfered portion 133a. In addition, the inner peripheral surface 1 of the second pressing ring 138
38a is an inclined surface that substantially faces the first chamfered portion 129a.

In the present embodiment, the inner peripheral surfaces 137a and 138a of the first and second pressing rings 137 and 138 are connected to the second and first chamfered portions 133a and 129a, respectively.
The slope is almost parallel to. However, the inner peripheral surfaces of these chamfered portions 133a, 133a, 129a need only be inclined surfaces substantially facing the second and first chamfered portions 133a, 129a.
It does not have to be substantially parallel to 29a. Further, the inclination angles of these inner peripheral surfaces may be different.

Furthermore, the first and second pressing rings 13
7, 138 are connected by a plurality of second bolts (displacement imparting means) 116 arranged at equal intervals in the circumferential direction. When the second bolt 116 is tightened, the first pressing ring 137 and the second pressing ring 138 are displaced in a direction relatively close to each other (vertical direction in the optical axis direction).

Therefore, the inner peripheral surface 137a of the first pressing ring 137 crushes the outer peripheral upper side of the O-ring 112a toward the inner peripheral lower side, and the inner peripheral surface 13 of the second pressing ring 138.
8a crushes the outer circumference lower side of the O-ring 112a toward the inner circumference upper side. Therefore, the upper and lower portions of the inner circumference of the O-ring 112 a are the first chamfered portion 129 a and the second chamfered portion 13.
It is strongly pressed by 3a and becomes a completely sealed state.

In this embodiment, the second bolt 116 is the first bolt.
And, a force is applied to the second pressing rings 137, 138 only in a plurality of positions in the circumferential direction so as to bring the two pressing rings 112a, 112b close to each other, but the first and second pressing rings 137, 138 have a continuous ring shape. Therefore, O
The ring 112a has a first and second ring all around its circumference.
A force for pressing the chamfered portions 129a and 133a acts. Therefore, the first and second chamfered portions 129a, 129a, 1
33a can be completely sealed over the entire circumference.

Then, the first and second chamfers 129
a, 133a and the first and second pressing rings 137, 13
By controlling the inclination angle of the inner peripheral surface of No. 8 and the tightening torque of the second bolt 116, the surface pressure for pressing the O-ring 112a against the first and second chamfered portions 129a and 133a can be controlled.

Similarly, a third pressing ring 139 is arranged above the outer circumference of the O-ring 112b, and a fourth pressing ring 140 is arranged below the outer circumference thereof. The inner peripheral surface 139a of the third pressing ring 139 is an inclined surface that substantially faces the fourth chamfered portion 130a. In addition, the inner peripheral surface 140a of the fourth pressing ring 140 is an inclined surface that substantially faces the third chamfered portion 133b.

In the present embodiment, the inner peripheral surfaces 139a and 140a of the third and fourth pressing rings 139 and 140 are provided with the fourth and third chamfered portions 130a and 133b, respectively.
The slope is almost parallel to. However, these inner peripheral surfaces 13
The chamfered portions 9a and 140a may be inclined surfaces that are substantially opposed to the chamfered portions that are substantially opposed to each other.
Need not be substantially parallel to. Further, the inclination angles of these inner peripheral surfaces may be different.

Furthermore, the third and fourth pressing rings 13
9, 140 are connected by a plurality of second bolts (displacement imparting means) 116 arranged at equal intervals in the circumferential direction. When the second bolt 116 is tightened, the third pressing ring 139 and the fourth pressing ring 140 are displaced in a direction in which they are relatively close to each other (vertical direction in the optical axis direction).

Therefore, the inner peripheral surface 139a of the third pressing ring 139 crushes the outer peripheral upper side of the O-ring 112b toward the inner peripheral lower side, and the inner peripheral surface 14 of the fourth pressing ring 140.
0 crushes the lower outer circumference of the O-ring 112b toward the upper inner circumference. Therefore, the upper and lower portions of the inner circumference of the O-ring 112b are the third chamfered portion 133b and the fourth chamfered portion 130.
It is strongly pressed by a and becomes a completely sealed state.

In this embodiment, the second bolt 116 is the first bolt.
And, a force is applied to the second pressing rings 137, 138 only in a plurality of positions in the circumferential direction so as to bring the two pressing rings 112a, 112b close to each other, but the first and second pressing rings 137, 138 have a continuous ring shape. Therefore, O
The ring 112a has a first and second ring all around its circumference.
A force for pressing the chamfered portions 129a and 133a acts. Therefore, the first and second chamfered portions 129a, 129a, 1
33a can be completely sealed over the entire circumference.

Then, the third and fourth chamfers 133
b, 140a and the third and fourth pressing rings 139, 14
By controlling the inclination angle of the inner peripheral surface of 0 and the tightening torque of the second bolt 116, the surface pressure that presses the O-ring 112b against the third and fourth chamfered portions 133b and 140a can be controlled.

In this embodiment, the first and second optical elements 121 and 122 and the outer peripheral surface of the first barrel member 129 are installed with a desired coaxiality, and similarly, the third and fourth optical elements 123 are arranged. , 124 and the outer peripheral surface of the second barrel member 130 are installed with a desired coaxiality. Therefore, by using the outer peripheral surfaces of the first barrel member 129 and the second barrel member 130,
After adjusting the optical axes of the fourth optical elements 121 to 124 and positioning them at desired positions with high precision, the first lens barrel member 129 and the second lens barrel member 130 are fastened with the first bolt 108.

Thereafter, by using the seal structure of the present embodiment, the O-ring 112a is pressed against the first chamfered portion 129a and the second chamfered portion 133a with an even force over the entire circumference thereof, and the O-ring 112b is moved to the third position. This is a procedure in which the chamfered portion 133b and the fourth chamfered portion 130a are pressed with a uniform force over the entire circumference thereof and sealed.

Therefore, as compared with the conventional case where the optical axis is adjusted with the O-ring sandwiched between the lens barrel units, the first and second lens barrel members 129, 130 and the third lens barrel members 129, 130 are provided.
The time spent for positioning the spacer 133 can be shortened, and the lens barrel 150 can be sealed with a simple structure.

The first embodiment described in the first embodiment is used.
When the outer diameters of the first barrel member 129, the second barrel member 130, and the third spacer 133 in the present embodiment are larger than those in the third cell members 4 to 6, the first embodiment will be described. With such a seal structure, the seal surface pressure becomes insufficient locally, and there is a possibility that outside air may flow into the lens barrel.

Therefore, in this embodiment, the O-ring 11
Chamfered portions 129a, 133a, 13 of 2a, 112b
3b, 130a second contact point pressure is insufficient
By increasing the tightening torque of the bolt 116, it is possible to locally adjust the contact surface pressure.

(Third Embodiment) FIG. 5 shows the arrangement of an exposure apparatus having a lens barrel 50 'using the seal structure described in the first embodiment as a projection optical system. In this figure, the direction of gravity coincides with the optical axis and is the -Z direction in the figure.

Reference numeral 51 is an illumination optical system, 52 is a reticle that is an original of a pattern to be transferred, and 53 is a reticle stage that holds the reticle 52. Reference numeral 54 is a surface plate for installing the projection optical system (lens barrel) 50 'at a predetermined position of the exposure apparatus main body.

55 is a wafer to which the pattern is transferred, 56
Is a wafer stage for holding the wafer 55.

The light source in the illumination optical system 51 has a wavelength of 4
36 nm g-line, wavelength 365 nm i-line, wavelength 248n
A KrF excimer laser having a wavelength of 193 nm, an ArF excimer laser having a wavelength of 193 nm, an F2 excimer laser having a wavelength of 157 nm, or the like is used.

The pattern area drawn on the reticle 52 is irradiated with light from the illumination optical system 51, and the projection optical system 5
It is reduced by a predetermined magnification (for example, ¼ or ⅕) by 0 ′ and transferred to the wafer 55 held on the wafer stage 56.

For the projection optical system 50 ', the reticle 52
By scanning the wafer 55, the pattern area of the reticle 52 is transferred onto the photosensitive material of the wafer 55. This scanning exposure is repeatedly performed on a plurality of transfer areas on the wafer 55.

In the projection optical system 50 ', in order to improve the light utilization efficiency, a gas inert to the photochemical reaction is supplied through the gas supply port 9 and the inert gas is discharged through the gas discharge port 10 for projection. Purge optics 50 '.

At this time, in order to prevent outside air from flowing in between the cell members holding the optical element, the cell members are sealed by the sealing structure described in the first embodiment. This makes it possible to prevent the deterioration of the optical characteristics and the uniformity of the illumination light, suppress the decrease of the exposure amount, and maintain and improve the performance of the exposure apparatus at a low cost by using a simple and space-saving structure.

The seal structure described in the second embodiment may be used instead of or in addition to the seal structure of the first embodiment.

Further, the exposure apparatus described in this embodiment is a step-and-scan type exposure apparatus, but the seal structure of the present invention can also be used in a stepper type exposure apparatus.

Further, although the case where the seal structure of the present invention is applied to the lens barrel forming the projection optical system has been described in the present embodiment, it may be applied to the lens barrel forming the illumination optical system. Then, the refraction type optical system in both optical systems,
The seal structure of the present invention may be applied to a catadioptric optical system and a reflective optical system.

Further, in each of the above-described embodiments, the case where the seal structure is provided in the lens barrel used in the exposure apparatus has been described. However, the seal structure of the present invention has a cylindrical body of another apparatus (for example, a pipe of a vacuum apparatus). ) Can also be applied to.

[0093]

As described above, according to the present invention,
Since the displacement imparting means displaces the first and second pressing members in a direction relatively approaching in the axial direction, the elastic member can be reliably pressed against the inclined surfaces of both annular members, which is simple. With the configuration, a perfect sealing effect can be obtained.

Further, since both the annular members that have been axially aligned are fastened by bolts or the like and then the elastic member may be arranged on the outer periphery thereof to seal the contact portion, the elastic member may interfere with the axial alignment of the annular members. And the time required for axis alignment can be shortened.

Moreover, the first and second displacement applying means
Even if a uniform displacement force is not applied to the entire circumference of the pressing member, a uniform pressing force can be applied to the elastic member from the first and second pressing members over the entire circumference thereof. Can be reliably sealed over the entire circumference.

According to the seal structure of the present invention, for example, when the optical element is held inside the cylindrical body, the outside air flows into the inner space of the cylindrical body, and further, the laser caused by the outside air (oxygen or the like) flowing in. It is possible to prevent absorption of light and the like, and it is possible to maintain and improve the optical performance of an exposure apparatus and the like using the same. Further, the outflow of the inert gas or the like from the inner space of the cylindrical body can be surely prevented.

[Brief description of drawings]

FIG. 1 is a perspective view (partially sectional view) of a lens barrel that is a first embodiment of the present invention.

FIG. 2 is an enlarged view of a seal structure used in the lens barrel.

FIG. 3 is a plan view and a side sectional view of a lens barrel that is a second embodiment of the present invention.

FIG. 4 is an enlarged view of a seal structure used in the lens barrel of the second embodiment.

FIG. 5 is a schematic configuration diagram of an exposure apparatus that is a third embodiment of the present invention.

FIG. 6 is a schematic view of a conventional seal structure.

[Explanation of symbols]

1-3 optical elements 4 to 6 cell members 4a, 5a Chamfer 7 Bonding material 8 first bolt 9 gas supply port 10 gas outlet 12 O-ring 13, 14 Pressing ring 15 Coupling member 16 Second bolt 50 lens barrel 112a, 112b O-ring 121-124 Optical element 125-128 cell members 129, 130 Lens barrel member 131,133 spacer 134 Presser ring 129a, 130a, 133a, 133b Chamfer 137-140 Pressing ring 150 lens barrel 50 'projection optical system 51 Illumination optical system 52 reticle 53 reticle stage 55 wafers 56 wafer stage 61,62 Optical element 63, 64 cell members 65, 66 barrel member 67 O-ring 68 Bonding material 69 volts 70 Presser ring AA vent

Claims (9)

[Claims] 1. A seal structure of a cylindrical body formed by contacting axial end faces of a first annular member and a second annular member with each other in an axial direction, and an outer periphery of a contact portion of the both annular members. An annular elastic member that forms an inclined surface having an inclination opposite to each other with respect to the axial direction, and is in contact with both the inclined surfaces, and is arranged on the outer peripheral side of the elastic member, and is generally formed on the inclined surface of the second annular member. An annular first pressing member having an inner peripheral surface which is inclined with respect to the axial direction so as to be opposed to and contacts the elastic member, and is inclined with respect to the axial direction so as to be substantially opposed to the inclined surface of the first annular member. And an annular second pressing member having an inner peripheral surface that comes into contact with the elastic member, and displacement applying means for displacing the first and second pressing members in a direction relatively approaching each other in the axial direction. A cylindrical seal structure characterized by. 2. The displacement imparting means respectively comprises the first
And two inner peripheral surfaces that are in contact with the outer peripheral surfaces of the second pressing member and are inclined with respect to the axial direction so as to be substantially opposed to the inclined surfaces of the second and first annular members, and radially inward. The sealing structure for a cylindrical body according to claim 1, wherein the sealing structure is a substantially annular tightening member that generates a tightening force. 3. The cylindrical seal structure according to claim 2, wherein the tightening member is formed by connecting at least two arc-shaped members in the circumferential direction. 4. The cylindrical seal structure according to claim 1, wherein the displacement applying means is a bolt mounted between the first and second pressing members. 5. A fastening member for fastening the first annular member and the second annular member is provided, and the sealing structure is provided outside the fastening member in the radial direction of the cylindrical body. The seal structure for a cylindrical body according to claim 1, wherein: 6. An apparatus comprising the cylindrical seal structure according to any one of claims 1 to 5. 7. An optical element holding structure, comprising the cylindrical seal structure according to claim 1, wherein an optical element is held inside the cylindrical body. 8. An optical element holding structure comprising the cylindrical seal structure according to claim 1, wherein a member holding an optical element is housed inside the cylindrical body. . 9. An exposure apparatus having the optical element holding structure according to claim 7, wherein the pattern of the original plate is transferred onto a substrate by exposure with light passing through the optical element.