WO2004081999A1

WO2004081999A1 - Optical device, exposure apparatus and method for manufacturing device

Info

Publication number: WO2004081999A1
Application number: PCT/JP2004/003190
Authority: WO
Inventors: Jin Nishikawa; Takashi Aoki
Original assignee: Nikon Corporation
Priority date: 2003-03-12
Filing date: 2004-03-11
Publication date: 2004-09-23
Also published as: TW200500815A; JPWO2004081999A1

Abstract

An optical device comprises a space formed on the optical path of an energy beam to which space a certain gas is supplied, an optical member placed on the boundary between the above-mentioned space and another space, a supporting member which has an opposing surface which faces the peripheral portion of the optical member and supports the peripheral portion of the optical member while leaving a gap between the opposing surface and the peripheral portion of the optical member, and a fluid sealing mechanism arranged between the peripheral portion of the optical member and the opposing surface of the supporting member. The fluid sealing mechanism comprises a magnetic fluid layer arranged between the peripheral portion of the optical member and the opposing surface, and a magnet for holding the magnetic fluid layer at a certain position.

Description

Optical apparatus, exposure apparatus, and device manufacturing method

The present invention relates to an optical device formed on an optical path of an energy beam and having a space to which a predetermined gas is supplied, and particularly relates to a semiconductor device, a liquid crystal display device, and an image pickup device (C

Exposure equipment for manufacturing electronic devices such as CDs), thin-film magnetic heads, etc.

The present invention relates to a technique used in a vice manufacturing method.

This application is based on Japanese Patent Application No. 2003-6771, filed on March 12, 2003.

Claim the priority, and the contents are incorporated herein. Background art

When an electronic device such as a semiconductor device or a liquid crystal display device is manufactured by a photolithography process, a pattern image of a mask or a reticle (hereinafter, referred to as a reticle) having a pattern formed thereon is exposed to a photosensitive material (resist) through a projection optical system. A projection exposure apparatus is used for projecting each projection (shot) area on a substrate coated with a substrate. The circuit of the electronic device is transferred by exposing a circuit pattern on a substrate to be exposed by the projection exposure apparatus, and is formed by post-processing.

In recent years, high-density integration of integrated circuits, that is, miniaturization of circuit patterns has been promoted. Therefore, the wavelength of the exposure illumination beam (exposure light) in the projection exposure apparatus tends to be shorter. In other words, a KrF excimer laser (wavelength: 248 nm) and a short-wavelength light source will be used instead of the mainstream mercury lamp until now, and even shorter-wavelength ArF excimer lasers will be used. Exposure equipment using (193 nm) is also entering the final stage. Exposure equipment using an F ₂ laser (157 nm) is being developed with the aim of achieving even higher density integration.

Beams with a wavelength of less than about 190 nm belong to the vacuum ultraviolet region, and these beams do not pass through air. This is because the energy of the beam is absorbed by substances such as oxygen molecules, water molecules, and carbon dioxide molecules (hereinafter referred to as light absorbing substances) contained in the air. Because.

In an exposure apparatus using exposure light in a vacuum ultraviolet region, it is necessary to reduce or eliminate the light-absorbing substance from the space on the optical path of the exposure light in order for the exposure light to reach the substrate to be exposed with sufficient illuminance. Therefore, in the exposure apparatus, for example, as shown in Japanese Patent Application Laid-Open No. Hei 6-260385 (corresponding to USP 5,559,584), a space on the optical path is surrounded by a housing, and the exposure light is exposed. In many cases, the space inside the housing is filled with a gas that is permeable to air. In this case, for example, if the total optical path length is 100 mm, it is considered practical that the concentration of the light absorbing substance in the space on the optical path is about 1 ppm or less.

In an optical apparatus such as the above-described exposure apparatus, which includes a lens barrel having a space on the optical path to which a predetermined gas is supplied, gas leakage is prevented by adopting a seal structure. As a seal structure, a technique of closing a gap by deforming a solid seal member such as a ring is common. However, in the above technique, when the optical member is disposed at the boundary between the space to which the predetermined gas is supplied, the external space, and the boundary, the optical member is deformed by the force (or the reaction force) to deform the seal member. May be deformed, leading to a decrease in optical performance. Disclosure of the invention

The present invention has been made in view of the above-described circumstances, and is intended to reduce the optical performance of an optical member between a space to which a predetermined gas is supplied and an external space without causing a decrease in the optical performance of the optical member. It is an object of the present invention to provide an optical device that can prevent intrusion and leakage of a liquid or the like. It is another object of the present invention to provide an exposure apparatus capable of improving exposure accuracy.

Another object of the present invention is to provide a device in which the accuracy of a formed pattern is improved.

In order to solve the above problem, a first aspect of the present invention is an optical device, comprising: a space (11) formed on an optical path of an energy beam (IL) and supplied with a predetermined gas. An optical member (14) disposed at a boundary between the space (11) and another space; and an opposing surface (20a) opposing a peripheral portion of the optical member (14). In a state where a gap is formed between the facing surface (20a) and the peripheral edge of the optical member (14), the light A support portion (20) for supporting the peripheral portion of the optical member (14); and a fluid disposed between the peripheral portion of the optical member (14) and the facing surface (20a) of the support portion (20). A sealing mechanism.

In this case, the fluid sealing mechanism includes a magnetic fluid layer (25) provided between a peripheral portion of the optical member (14) and the facing surface (20a), and a magnetic fluid layer (25). And a magnet (26) for holding in position.

In this optical device, the optical member is supported in a state where a gap is formed between the peripheral portion of the optical member and the support portion, and a magnetic fluid layer is provided between the peripheral portion of the optical member and the support portion. The magnetic fluid is a suspension in which a fine powder of a ferromagnetic material is dispersed in a medium such as a liquid, and aggregates when a magnetic field is applied. By holding the magnetic fluid layer at a predetermined position by the magnet, it is possible to prevent gas from leaking through boundaries of a plurality of spaces.

Also, in a seal structure using a magnetic fluid layer, a force acting on an optical member due to the seal is smaller than a structure using a solid seal member such as a ring. Therefore, in this optical device, when the optical member is arranged at the boundary of the plurality of spaces, the deformation of the optical member is suppressed. Further, in the seal structure using the magnetic fluid layer, the restrictions on the posture of the optical member are small, and the arrangement of the optical member can be easily adjusted.

In the above optical device, the use of a fluorine-based base liquid as the magnetic fluid layer (25) improves the degree of chemical cleanliness.

In the above optical device, the optical member (14) may include, for example, an optical surface (14a) having an optically effective area, and a peripheral surface (14c) in the same plane as the optical surface (14a). ), And a side surface (14 e) of the optical member, wherein the magnetic fluid layer (25) has at least a peripheral surface (14 c) of the optical member and a side surface (14 e) of the optical member. Both are arranged so as to be in contact with one.

In this case, the magnetic fluid layer (25) is arranged so as to be in contact with a peripheral surface (14c) in a peripheral portion of the optical member, and the peripheral surface (14c) is disposed on the magnetic fluid layer (14). The part in contact with 25) should have been treated to a different surface property than the other parts. Alternatively, the magnetic fluid layer (41) is disposed so as to be in contact with the side surface (14e) of the optical member, and the side surface (14e) is in contact with the magnetic fluid layer (41). It is preferred that one part has a different surface property than the other part.

Since the surface characteristics of the portion in contact with the magnetic fluid layer are different from those of the other portions, it is possible to improve the retention and sealing properties of the magnetic fluid layer.

For example, by forming a magnetic metal film in a portion where the magnetic fluid layer is in contact, a magnetic force circuit via the magnet is reliably formed, and the retention and sealing properties of the magnetic fluid layer can be improved. .

In addition, for example, by improving the wettability of the portion where the magnetic fluid layer is in contact with the magnetic fluid layer, it is possible to improve the retention and sealing properties of the magnetic fluid layer. Further, in the above optical device, the peripheral portion of the optical member (14) has planes (14c, 14d) parallel to each other, and the support section (20) is one of the planes parallel to each other. 14 c), and three seats (27) that support the periphery of the optical member (14) at substantially equal intervals; and three seats (27) are disposed at positions corresponding to the three seats (27), respectively. The magnetic fluid layer having three pressing members (28) that are in contact with the other of the parallel surfaces (14d) and that sandwich the peripheral edge of the optical member (14) together with the three seats (27). (25) is preferably in contact with at least one (14c) of the parallel surfaces.

In this optical device, the three seats and the three pressing members act so that the force for holding the optical member presses the optical member therebetween. Therefore, the occurrence of bending moment inside the optical member is suppressed, and the occurrence of distortion of the optical member is suppressed. In the above optical device, the magnet (26) is embedded in a part of the facing surface (20a), so that the magnetic fluid layer is held at the embedded position.

Further, in the above optical device, the magnet (26) may be arranged in a convex shape on the facing surface (20a).

By arranging the magnets on the opposing surface in a convex shape, a magnetic circuit is preferably formed, and the retention of the magnetic fluid layer is improved.

A gas different from the predetermined gas may be supplied to the other space.

A second aspect of the present invention is an exposure apparatus, comprising: an illumination system (121) for illuminating a mask (R) on which a pattern is formed with an energy beam (IL); At least one of the projection optical system (PL) for transferring the pattern onto the substrate (W) is constituted by the above optical device.

In this exposure apparatus, gas leakage in the optical apparatus is prevented, and optical performance is improved, so that exposure accuracy is improved.

In the above-described exposure apparatus, for example, the optical member is an optical element (351) facing the substrate (W) among a plurality of optical elements constituting the projection optical system (PL); The space (301) in the projection optical system (PL), and the other space is a space (303) between the optical element (351) and the substrate (W).

In this case, a first gas supply mechanism (310) for supplying a first gas to the space (301) in the projection optical system (PL), the optical element (351) and the substrate (W) A second gas supply mechanism (31 1) for supplying a second gas different in type from the first gas in the space (303) between the first space and the second space (303). Different types of gases are supplied to the space 301 between the optical element and the substrate, and leakage of gas through the boundary between the spaces is prevented.

In the above exposure apparatus, for example, the optical member is an optical element (350) arranged on the mask (R) side among a plurality of optical elements constituting the projection optical system (PL). Yes. The space is a space (301) in the projection optical system (PL), and the other space is a space (302) between the optical element (350) and the mask (R). is there.

In this case, a first gas supply mechanism (310) for supplying a first gas to a space (301) in the projection optical system (PL), the optical element (350) and the mask (R) A second gas supply mechanism (31 1) for supplying a second gas different in type from the first gas in a space (302) between the first optical system and the projection optical system (PL). Different types of gases are supplied to the space (301) and the space (302) between the optical element and the mask, and gas leakage through the boundary between the spaces is prevented.

Further, the other space may be a liquid atmosphere. A third aspect of the present invention is a device manufacturing method, which includes a step of transferring a device pattern formed on a mask (R) onto a substrate (W) using the above exposure apparatus.

According to this device manufacturing method, it is possible to provide a device in which the accuracy of a formed pattern is improved by improving the exposure accuracy. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram schematically showing a first embodiment of the optical device according to the present invention. FIG. 2 is a partially enlarged view showing a seal structure using a magnetic fluid. FIG. 3 is a cross-sectional view taken along the line AA shown in FIG.

FIG. 4 is a diagram illustrating an example in which a portion of the optical member that is in contact with the magnetic fluid layer is processed to have a different surface characteristic from other portions.

FIG. 5 is a diagram showing another example in which a portion of the optical member that contacts the magnetic fluid layer is processed to have a different surface characteristic from other portions.

FIG. 6 is a diagram illustrating an example in which magnets are arranged in a convex shape on a surface.

FIG. 7 is a view showing an optical device according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a third embodiment of the optical device according to the present invention.

FIG. 9 is a diagram showing an embodiment in which the optical device of the present invention is applied to an exposure apparatus. FIG. 10 is a diagram showing an example of the configuration of a gas supply system that supplies gas to each space on the optical path of exposure light. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of an optical device according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and for example, the components of these embodiments may be appropriately combined.

FIG. 1 is a diagram schematically showing a first embodiment of the optical device according to the present invention. The optical device 10 includes a space 11 formed on the optical path of the energy beam IL and supplied with a predetermined gas. This space 11 is an internal space of a cylindrical housing 12 constituting the optical device 10. The boundary between this space 11 and the external space 13 is Lumber 14 is arranged. That is, an opening 15 through which the energy beam IL passes is formed in the housing 12, and the optical member 14 is arranged so as to close the opening 15. Further, in this example, the optical member 14 is formed of a parallel flat plate (parallel flat plate) having surfaces parallel to each other, and has optical surfaces 14 a and 14 b having an optically effective area. It includes peripheral surfaces 14 c and 14 d and a side surface 14 e in the same plane. The optical surface 14a and the optical surface 14b are parallel to each other, and the peripheral surface 14c and the peripheral surface 14d are also parallel to each other.

In the optical device 10, a fluid seal mechanism is provided between the optical member 14 and the housing 12, and the fluid seal mechanism seals the space between the optical member 14 and the housing 12. I have. In the present embodiment, an example in which a magnetic fluid is used as a fluid seal mechanism will be described.

Figure 2 shows a partially enlarged seal structure using a magnetic fluid.

In FIG. 2, a support portion 20 that supports the optical member 14 is provided at an axial end of the housing 12. The supporting portion 20 has an opposing surface 20 a facing one peripheral surface 14 c of the optical member 14, and the opposing surface 20 a and the peripheral surface 14 c of the optical member 14 are provided. The optical member 14 is supported with a gap formed therebetween. Further, a magnetic fluid layer 25 made of a magnetic fluid is provided between the peripheral surface 14 c of the optical member 14 and the facing surface 20 a of the support portion 20. The magnetic fluid layer 25 is held at a predetermined position by a magnet 26 (permanent magnet) disposed on the facing surface 20a. FIG. 3 is a cross-sectional view taken along the line AA shown in FIG.

In FIG. 3 and FIG. 2 described above, the support portion 20 comes into contact with one of the peripheral surfaces 14 c at the peripheral portion of the optical member 14, and the peripheral portions of the optical member 14 are substantially equally spaced (in this example, It has three seats 27 that are supported at intervals of 120 ° in the circumferential direction. These seats 27 are formed so as to protrude from the facing surface 20 a of the support portion 20, and have a small contact area with the optical member 1.

Further, the support portion 20 is disposed at a position corresponding to each of the three seats 27, contacts the other peripheral surface 14d of the optical member 14, and fixes the peripheral portion of the optical member 14 to the above. It has three lens pressing members 28 sandwiched together with the three seats 27. These three lens pressing members 28 include a portion that contacts the optical member 14 (the lens pressing portion). 2 9) is formed so as to protrude, and the contact area with the optical member 14 is small. The lens pressing portion 29 of the lens pressing member 28 is disposed so as to have a positional relationship facing the seat 27 with the optical member 14 interposed therebetween (a relationship in which the two are located on the same axis L1). You. That is, the respective lens pressing portions 29 of the lens pressing member 28 are substantially equidistant from each other in the circumferential direction so as to face the seat 27 on the facing surface 20a (in this example, 1 in the circumferential direction). 20 ° intervals). In the present example, the three lens pressing members 28 are individually fixed to the housing 12, but may be integrally fixed to the housing 12. That is, the lens pressing member may have a structure in which, for example, three protruding portions (lens pressing portions) are provided in one member.

The magnet 26 is embedded in a part of the facing surface 20a of the support portion 20. Further, the magnet 26 has an N-pole portion and an S-pole portion, and the N-pole portion and the S-pole portion are arranged side by side along the peripheral surface 14 c of the optical member 14. I have. The magnetic flux generated from the magnet 26 circulates by forming a magnetic circuit 26a as shown by a dashed line in FIG. The magnetic fluid layer 25 is aggregated and restrained by the magnetic flux of the magnet 26, and is held at the position where the magnet 26 is embedded on the facing surface 20a. Note that, in the magnet 26, the N pole and the S pole may be arranged in reverse to those shown in FIG.

A magnetic fluid is a suspension in which fine powder of a ferromagnetic material (eg, iron powder) is dispersed in a medium such as a liquid (base liquid, base oil), and aggregates when a magnetic field is applied. As the base liquid, those having a low vapor pressure and low degassing are preferable. For example, alkylnaphthylene, perfluoropolyether and the like are used. By using a fluorine-based material such as perfluoropolyether as the base liquid, the degree of chemical cleanliness can be improved. The magnetic fluid may include an activator for promoting the dispersion of the fine powder of the magnetic material.

In the optical device 10 having the above configuration, the inner space 11 and the outer space 13 of the housing 12 are formed by the magnetic fluid layer 25 provided between the peripheral portion of the optical member 14 and the support portion 20. Gas leaks at the boundary with are prevented. In other words, in the seal structure using the magnetic fluid, the magnetic fluid layer 25 is in contact with the optical member 14 and the support portion 20 over the entire periphery of the optical member 14, and the magnetic fluid layer 25 is formed by the wall. As a result, the gas flow between the inner space 11 and the outer space 13 is reliably shut off. And magnetic current Deterioration of the body over time is small, and the change over time of the sealing performance is extremely small. Therefore, in the optical device 10, it is possible to stably fill the inside of the housing 12 with a predetermined gas with high purity due to high sealing performance.

Further, in a seal structure using a magnetic fluid, a force acting on the optical member 14 due to the seal can be reduced as compared with a structure using a solid seal member such as an O-ring. That is, since the magnetic fluid layer 25 is held by the magnetic force of the magnet 26 and the viscosity of the magnetic fluid, the force acting on the optical member 14 with the holding is small. Therefore, in the optical device 10, the deformation of the optical member 14 due to the holding is suppressed, and the optical performance is improved. Moreover, in the seal structure using the magnetic fluid, the frictional resistance between the magnetic fluid as the seal member and the object is smaller than that of the O-ring, and the shape of the magnetic fluid layer 25 is easily changed. Therefore, restrictions on the posture of the optical member 14 are small, and adjustment of the arrangement of the optical member 14 is easy.

In the optical device 10, three seats 27 of the support portion 20 are in contact with one peripheral surface 14 c of the optical member 14, and three peripheral surfaces 14 d of the optical member 14 are three. The lens pressing portion 29 of the lens pressing member 28 comes into contact with the lens pressing portion 29, and the seat 27 and the lens pressing portion 29 are arranged to face each other with the optical member 14 interposed therebetween. Therefore, the force of the pressing force of the lens pressing member 28 acts so as to press on the same axis L1 with the optical member 14 interposed therebetween, and the bending moment occurs inside the optical member 14 due to the holding. Is suppressed. Therefore, in the optical device 10, the occurrence of distortion of the optical member 14 is suppressed, and optical performance is improved.

In the optical device 10, the magnetic fluid layer 25 is disposed between the peripheral surface 14 c of the optical member 14 and the facing surface 20 a of the support portion 20, The gap in which the member 25 is arranged, that is, the distance between one peripheral portion 14 c of the optical member 14 and the facing surface 20 a of the support portion 20 is defined by the seat 27. In this case, a change in the shape of the magnetic fluid layer 25 such as the thickness of the magnetic fluid layer 25 is less likely to occur, and a decrease in sealing performance is unlikely to occur.

Here, of the peripheral surface 14 c of the optical member 14, a portion in contact with the magnetic fluid layer 25 is preferably processed to have a different surface characteristic from other portions. This makes it possible to improve the retention and sealing properties of the magnetic fluid layer 25. For example, as shown in FIG. 4, a film 30 of a substance having magnetic properties (such as a metal) may be formed on a portion of the peripheral surface 14 c in contact with the magnetic fluid layer 25. As a result, a magnetic circuit having the magnetic film 30 as a part of the magnetic flux path is stably formed, and the holding and sealing properties of the magnetic fluid layer 25 are improved. Further, a metal film may be formed on the peripheral surface 14 c of the optical member 14 to be magnetized, or a magnet (permanent magnet) may be provided.

Also, for example, as shown in FIG. 5, a portion of the peripheral surface 14c that is in contact with the magnetic fluid layer 25 is subjected to a surface treatment so as to have lyophilicity for the magnetic fluid (base liquid, base oil). Is also good. Thereby, the wettability of the magnetic fluid layer 25 with respect to the optical member 14 is improved, and the retention and sealing properties of the magnetic fluid layer 25 are improved. In this case, the other part of the peripheral surface 14 c of the optical member 14 is treated to be lyophobic with respect to the magnetic fluid layer 25, so that the magnetic fluid layer 25 can be further retained. In addition, not only the optical member 14 but also a similar surface treatment may be applied to the support portion 20. In the lyophilic surface treatment, for example, a film that is lyophilic to a magnetic fluid may be formed on the surface of the optical member. Similarly, for the liquid-repellent surface treatment, for example, it is preferable to form a film that is lyophilic to the magnetic fluid on the surface of the optical member.

Further, as shown in FIG. 6, the magnet 26 may be arranged in a convex shape on the facing surface 20a of the support portion 20. That is, in FIG. 6, the magnet 26 is disposed so as to protrude from other portions on the facing surface 20a. In this case, compared to the case where the magnet 26 shown in FIG. 2 is embedded in the object, the object is less around the magnet 26 and the magnetic circuit is formed well. That is, the magnetic flux of the magnet 26 is easily characterized as a magnetic circuit. Therefore, the retention of the magnetic fluid layer 25 is improved.

FIG. 7 is a view showing a second embodiment of the optical device according to the present invention, and shows a partially enlarged seal structure using a magnetic fluid. In the present embodiment, components having the same functions as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted or simplified.

In FIG. 7, in the optical device 40, the space between the optical member 14 and the housing 12 is sealed using a magnetic fluid, as in the first embodiment. In the present embodiment, the magnetic fluid layer 41 made of a magnetic fluid is arranged so as to be in contact with the side surface 14 e at the peripheral portion of the optical member 14. That is, a support portion 42 that supports the optical member 14 is provided at an axial end of the housing 12. As in the first embodiment, the support portion 42 comes into contact with one of the peripheral surfaces 14 c on the peripheral portion of the optical member 14, and the peripheral portions of the optical member 14 are substantially equally spaced (in the circumferential direction). (At an interval of 120 °) and three seats 4 3, which are arranged at positions corresponding to the three seats 4 3, respectively, and are in contact with the other peripheral surface 14 d of the optical member 14, and It has three lens pressing members 44 that sandwich the peripheral edge of the member 14 together with the three seats 43. In addition, the support part 42 has an opposing surface 42 a opposing one peripheral surface 14 c of the optical member 14 and an opposing surface 42 b opposing the side surface 14 e of the optical member 14. In this state, gaps are formed between the facing surface 42 a and the peripheral surface 14 c of the optical member 14, and between the facing surface 42 b and the side surface 14 e of the optical member 14. Supports the optical member 14. In the embodiment, the magnetic fluid layer 41 is provided between the side surface 14 e of the optical member 14 and the opposing surface 42 b of the support portion 42. The magnetic fluid layer 41 is held at a predetermined position by a magnet 46 (permanent magnet) embedded in the facing surface 42b.

In the optical device 40 of this example, similarly to the first embodiment, the magnetic fluid layer 41 provided between the side surface 14 e of the optical member 14 and the opposing surface 42 b of the support portion 42 is provided. This prevents gas leakage at the boundary between the inner space 11 and the outer space 13 of the housing 12. Further, in this example, since the magnetic fluid layer 41 is disposed so as to be in contact with the side surface 14 e of the optical member 14, the optical member 14 slightly moves in the optical axis direction or the optical member 14 is The shape change of the magnetic fluid layer 41 is small even if it rotates around. Therefore, position adjustment of the optical member 14 in the optical axis direction and adjustment of the rotation angle of the optical member 14 can be easily performed. Also in this example, by forming a film of a magnetic substance (metal) on the surface of the side surface 14 e of the optical member 14, or by applying a surface treatment having lyophilic property to the magnetic fluid. Thus, the retention and sealing properties of the magnetic fluid layer 41 are improved.

FIG. 8 is a view showing a third embodiment of the optical device according to the present invention, and shows a partially enlarged seal structure using a magnetic fluid. In the present embodiment, components having the same functions as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted or omitted.

In FIG. 8, in the optical device 50, the optical members 14 and A magnetic fluid is sealed between the housing 12 and the magnetic fluid layer 51, and a magnetic fluid layer 51 made of a magnetic fluid is disposed on the side surface 14 e at the periphery of the optical member 14.

That is, a support portion 52 that supports the optical member 14 is provided at an axial end of the housing 12. As in the second embodiment, the supporting portion 52 comes into contact with one of the peripheral surfaces 14 c of the peripheral portion of the optical member 14, and the peripheral portions of the optical member 14 are substantially equally spaced (in the circumferential direction). 1 2 0 ° · spacing) and are arranged at positions corresponding to the three seats 5 3 and the three seats 5 3, respectively, and contact the other peripheral surface 14 d of the optical member 14, and It has three lens pressing members 54 that sandwich the peripheral portion of the optical member 14 together with the three seats 53. Further, the support portion 52 has an opposing surface 52 a opposing the one peripheral surface 14 c of the optical member 14 and an opposing surface 52 b opposing the side surface 14 e of the optical member 14. In this state, gaps are formed between the facing surface 52 a and the peripheral surface 14 c of the optical member 14, and between the facing surface 52 b and the side surface 14 e of the optical member 14. Supports the optical member 14. A magnetic fluid (magnetic fluid layer 51) is arranged between the side surface 14 e of the optical member 14 and the facing surface 52 b of the support portion 52. In the present embodiment, the magnetic fluid layer 51 includes a housing (a first housing 55, a second housing 5 6) disposed on the side surface 14 e of the optical member 14 and the opposing surface 52 b. ).

The first housing 55 is formed in an annular shape, and is disposed on the side surface 14 e of the optical member 14 by interference fit or adhesive fixing. A concave portion 55a is formed in the outer peripheral surface of the first housing 55, and a magnetic fluid is accommodated in the concave portion 55a (magnetic fluid layer 51). The second housing 56 is formed in an annular shape, and is disposed on the facing surface 52 b of the support portion 52 by, for example, bonding and fixing. A concave portion 56a is formed on the inner peripheral surface of the second housing 56, and a magnetic fluid is accommodated in the concave portion 56a (magnetic fluid layer 51). The first housing 55 and the second housing 56 are arranged such that the respective recesses 55a and 56a face each other with a gap therebetween. In the above-mentioned adhesive fixing, it is preferable to use a door seal or a fluorine-based adhesive in order to improve the chemical cleanliness.

A magnet 57 (permanent) is provided between the first housing 55 and the second housing 56. Is located. The magnet 57 is formed in an annular shape, and is supported by, for example, a seating surface provided on one of the housings 55 and 56. In addition, a part of the inner periphery of the magnet 57 is inserted into the recess 55 a of the first housing 5.5, and a part of the outer periphery of the magnet 57 is recessed 5 6 of the second housing 56. Inserted in a. The magnet 57 holds the magnetic fluid in the recesses 55a, 56a of the housings 55, 56.

In the optical device 50 of the present example, similarly to the second embodiment, the magnetic fluid layer 51 provided between the side surface 14 e of the optical member 14 and the opposing surface 52 b of the support portion 52 is provided. This prevents gas leakage at the boundary between the inner space 11 and the outer space 13 of the housing 12. In this example, since the magnetic fluid layer 51 is disposed on the side surface 14 e of the optical member 14, the optical member 14 slightly moves in the optical axis direction or the optical member 14 rotates around the axis. The shape of the magnetic fluid layer 51 is small. Therefore, the position adjustment of the optical member 14 in the optical axis direction and the adjustment of the rotation angle of the optical member 14 can be easily performed. Further, in this example, the magnetic fluid layer 51 is disposed in the concave portions 55a and 56a of the housings 55 and 56, and the vertical downward movement of the magnetic fluid (movement due to gravity) is stopped. The magnetic fluid layer 51 is securely held at a predetermined position.

FIG. 9 shows an embodiment in which the optical device of the present invention is applied to an exposure apparatus. Note that FIG. 9 uses an XYZ rectangular coordinate system. In the XYZ orthogonal coordinate system, the X axis and the Y axis are set so as to be parallel to the wafer stage WS that holds the wafer W as a substrate (photosensitive substrate), and the Z axis is orthogonal to the wafer stage WS. The direction is set to Actually, in the XYZ rectangular coordinate system in the figure, the XY plane is set to a plane parallel to the horizontal plane, and the Z axis is set to the vertical direction.

Exposure apparatus according to this embodiment uses an F ₂ laser light source as the exposure light source. Also, by synchronously scanning the reticle R and the wafer W in a predetermined direction relative to an illumination area of a predetermined shape on the reticle R as a mask (projection master), one shot area on the wafer W is obtained. In addition, a step-and-scan method in which the pattern image of the reticle R is sequentially transferred is adopted. In such a step-and-scan-type exposure apparatus, the pattern of the reticle R can be exposed on an area on the substrate (wafer W) wider than the exposure field of the projection optical system. In FIG. 9, an exposure apparatus 100 includes a laser light source 120, an illumination optical system 122 that illuminates a reticle R with an exposure light IL as an energy beam from the laser light source 120, and a reticle R. A projection optical system PL for projecting the exposure light IL emitted from the wafer onto the wafer W, and a main controller (not shown) for controlling the entire apparatus in its entirety. Further, the exposure apparatus 100 is housed in a chamber (not shown) as a whole.

The laser light source 120 has an F ₂ laser that outputs pulsed ultraviolet light having an oscillation wavelength of 157 nm. The laser light source 120 is also provided with a light source control device (not shown). The light source control device responds to an instruction from the main control device, and the oscillation center wavelength and the wavelength of the emitted pulse ultraviolet light are controlled. Controls the half width of the vector, triggers the pulse oscillation, and controls the gas in the laser chamber.

The pulse laser light (illumination light) from the laser light source 120 is deflected by the deflecting mirror 130 and is incident on the variable dimmer 131 as an optical attenuator. In the variable dimmer 131, the dimming rate can be adjusted stepwise or continuously to control the amount of exposure to the photoresist on the wafer. The illumination light emitted from the variable attenuator 13 1 is deflected by the optical path deflection mirror 13 2, and then the first fly-eye lens 13 3, zoom lens 13 4, vibrating mirror 13 5, etc. The second fly-eye lens 1 36 reaches through the order. On the exit side of the second fly-eye lens 13 6, a switching revolver 13 7 for the aperture stop of the illumination optical system for setting the size and shape of the effective light source as desired is arranged. In the present embodiment, the magnitude of the light beam to the second fly-eye lens 1336 by the zoom lens 134 is made variable in order to reduce the light amount loss at the aperture stop of the illumination optical system.

The light beam emitted from the aperture of the illumination optical system aperture stop illuminates the illumination field stop (reticle blind) 141 via the condenser lens group 140. The illumination field stop 1441 is disclosed in Japanese Patent Application Laid-Open No. Hei 4-19613 and US Patent Nos. 5,473,410 corresponding thereto.

Light from the illumination field stop 14 1 is applied to an illumination field stop imaging optical system (reticle blind imaging system) consisting of deflection mirrors 144 2 and 1 45 and lens groups 144 3, 144 4 and 1 46. On the reticle R through the reticle R, the illumination field stop 1 4 1 aperture An illumination area, which is an image of the part, is formed. Light from the illumination area on the reticle R is guided to the wafer W via the projection optical system PL, and a reduced image of the pattern in the illumination area of the reticle R is formed on the wafer "W. The reticle stage RS for holding the wafer W can be moved two-dimensionally in the XY plane, and its position coordinates are measured and controlled by the interferometer 150. The wafer stage WS for holding the wafer W is also XY It can be moved two-dimensionally in a plane, and its position coordinates are measured and controlled by the interferometer 151. These make it possible to synchronously scan the reticle R and the wafer W with high accuracy. The illumination optical system 121 is configured by the above-described laser light source 120 to the illumination field stop imaging optical system and the like.

When the light in the vacuum ultraviolet region is used as the exposure light, such as the F ₂ laser light (wavelength: 157 nm) used in the present embodiment, the optical glass material (optical element) having a good transmittance is fluorite. (CaF ₂ crystal), quartz glass doped with fluorine or hydrogen, magnesium fluoride (MgF ₂ ), etc. In this case, in the projection optical system PL, it is difficult to obtain desired imaging characteristics (such as chromatic aberration characteristics) by using only the refractive optical member. A refraction system may be used.

As the light absorbing material for light in the vacuum ultraviolet region, oxygen (0 _2), water (water vapor: H ₂ 0), carbon monoxide (CO), carbon dioxide (CO: C0 _2), organic matter, and c androgenic Compound. On the other hand, gases that transmit light in the vacuum ultraviolet region (substances with little energy absorption) include nitrogen gas (N ₂ ), hydrogen (H ₂ ), helium (He), neon (Ne), and argon. (Ar), krypton (Kr), xenon (Xe) and radon (Rn). Hereinafter, the nitrogen gas and the rare gas will be collectively referred to as “transparent gas”. In the present embodiment, the illumination optical path (the optical path from the laser light source 120 to the reticle R) and the projection optical path (the optical path from the reticle R to the wafer W) are cut off from the external atmosphere, and those optical paths are shielded from light in the vacuum ultraviolet region. It is filled with a gas such as nitrogen, helium, argon, neon, krypton, xenon, radon, or a mixture of these as a permeable gas with low absorption characteristics.

Specifically, the optical path from the laser light source 120 to the variable attenuator 131 is cut off from the external atmosphere by a casing 160, and the illumination field stop 14 is provided from the variable attenuator 131. The optical path up to 1 is cut off from the outside atmosphere by casing 161, the illumination field stop, the imaging optical system is cut off from the outside atmosphere by the casing 162, and these light paths are filled with the above permeable gas. I have. The casing 16 1 and the casing 16 2 are connected by the casing 16 3. Also, the projection optical system PL itself has a lens barrel 169 as a casing, and its internal optical path is filled with the above-mentioned permeable gas.

In addition, the casing 164 shields the space between the casing 162 containing the illumination field stop imaging optical system and the projection optical system PL from the external atmosphere, and a reticle is provided inside. A reticle stage RS that holds R is housed. The casing 1 64 is provided with a door 170 for loading / unloading the reticle R. Outside the door 170, the casing 1 is provided for loading / unloading the reticle R. A gas replacement chamber 165 is provided to prevent contamination of the atmosphere in 64. This gas exchange chamber 16 5 is also provided with a door 17 1, and reticle delivery to and from the reticle storage force 16 6 that stores multiple types of reticles is performed via the door 17 1. Is Further, the casing 167 shields the space between the projection optical system PL and the wafer W from the outside atmosphere, and the wafer stage WS holding the wafer W via the wafer holder 180 inside the casing 167. The oblique incidence type autofocus sensor 181 for detecting the Z direction position (focus position) and tilt angle on the surface of the wafer W, the off-axis type alignment sensor 182, and the wafer stage WS are mounted. The surface plate 1 8 3 etc. are stored. The casing 167 is provided with a door 172 for loading / unloading the wafer W. The outside of the door 172 is contaminated with the atmosphere inside the casing 167. A gas replacement chamber 168 is provided to prevent this. The gas replacement chamber 168 is provided with a door 173, through which the wafer W is loaded into the apparatus and the wafer W is unloaded outside the apparatus. As the permeable gas (purge gas) filled in the space on each optical path, it is preferable to use nitrogen or a helium. Nitrogen acts as a light absorbing substance for light having a wavelength of about 150 nm or less, and helium can be used as a transparent gas for light having a wavelength of about 100 nm or less. The hemisphere has a thermal conductivity about 6 times that of nitrogen, and the amount of change in the refractive index due to a change in atmospheric pressure is about 1 Z8 of nitrogen. The optical system is excellent in stability of imaging characteristics and cooling performance. Note that helium may be used as a transmissive gas for the lens barrel of the projection optical system PL, and nitrogen may be used as a transmissive gas for other optical paths (for example, an illumination optical path from the laser light source 120 to the reticle R).

Here, each of the casings 161, 162, 164, 167 is provided with an air supply valve 200, 201, 202, 203, and these air supply valves 200 to 203 are provided with a gas supply system (not shown). Is connected to the air supply line. Further, each of the casings 161, 162, 164, 167 is provided with an exhaust valve 210, 211, 212, 213. These exhaust valves 210 to 213 are respectively provided with exhaust gas in the gas supply system. Connected to pipeline.

Similarly, the gas replacement chambers 165 and 168 are also provided with exhaust valves 204 and 205 and exhaust valves 214 and 215, respectively, and the lens barrel 169 of the projection optical system PL is also provided with an air supply valve 206 and an exhaust valve 216. These are connected to the supply line or exhaust line in the gas supply system.

Further, in the gas replacement chambers 165 and 168, it is necessary to perform gas replacement at the time of reticle exchange or wafer exchange. For example, when replacing the reticle, the door 171 is opened, the reticle is carried into the gas replacement chamber 165 from the reticle storage force 166, the door 171 is closed, and the gas replacement chamber 165 is filled with the permeable gas. Open and place the reticle on reticle stage RS. When replacing the wafer, the door 173 is opened, the wafer is carried into the gas replacement chamber 168, and the door 173 is closed to fill the gas replacement chamber 168 with the permeable gas. Thereafter, the door 172 is opened and the wafer is placed on the wafer holder 180. In the case of unloading the reticle and unloading the wafer, the procedure is reversed. When the gas in the gas replacement chambers 165 and 168 is replaced, the permeable gas may be supplied from the air supply valve after the pressure in the gas replacement chamber is reduced. Further, in the casings 164 and 167, there is a possibility that the gas which has undergone gas replacement in the gas replacement chambers 165 and 168 may be mixed in, and a considerable amount of gas is contained in the gas in the gas replacement chambers 165 and 168. It is highly possible that light-absorbing substances such as oxygen are mixed. Therefore, it is desirable to perform gas replacement at the same timing as gas replacement in the gas replacement chambers 165 and 168. In the casing and gas replacement chamber, It is preferable to fill with a permeable gas having a pressure higher than the pressure of the gas.

FIG. 10 shows an example of a configuration of a gas supply system 300 that supplies the above-mentioned transparent gas as a purge gas to each space on the optical path of the above-mentioned exposure light. In FIG. 10, among the spaces on the optical path of the above-described exposure light IL, the space 301 inside the lens barrel 169 in the projection optical system PL and the space 302 inside the casing 164 for accommodating the reticle stage RS are shown as supply destinations of the permeable gas. The space 303 inside the casing 167 that houses the wafer stage WS is representatively shown. In this example, the space 301 is supplied with helium gas (He), and the spaces 302 and 303 are supplied with nitrogen gas (N ₂ ). One of helium gas and nitrogen gas is appropriately supplied to the other spaces among the spaces on the optical path of the exposure light.

The gas supply system 300 includes a first gas supply mechanism 310 for helium gas and a second gas supply mechanism 311 for nitrogen gas. The first gas supply mechanism 310 and the second gas supply mechanism 311 are respectively provided with gas supply sources 320 and 321 such as gas cylinders containing helium gas or nitrogen gas, and gas from the gas supply sources 320 and 321 to each space on the optical path. Gas supply devices 322, 323, and 324 that supply gas, and exhaust devices 325 and 326 that discharge gas containing gas from each space on the optical path. Note that the gas supply system 300 may appropriately include a filter, a temperature controller for controlling the temperature of the gas, and a concentration meter for measuring the concentration of the light absorbing substance in each space on the optical path.

The gas supply devices 322, 323, and 324, for example, pressurize the gas sent from the gas supply sources 320 and 321 and send the gas to the spaces 301, 302, and 303 via the air supply lines 330, 331, and 332. Supply. Note that when the gas discharged from the gas supply sources 320 and 321 has a sufficient pressure, the gas supply device can be omitted. The piping used for the air supply lines 330, 331, and 332 may be, for example, metal such as washed stainless steel, or washed tetraethylene, tetrafluoroethylene-terefluoro (alkyl vinyl ether), or the like. Various chemicals such as tetrafluoroethylene-hexafluoro-probe copolymer and other chemical-clean materials are used.Piping fittings are, for example, oil-free stainless steel. Made of metal or various polymers It is.

The exhaust devices 3 2 5 and 3 2 6 are, for example, by generating a vacuum pressure, so that the space 3 0 1, 3 0 2 and 3 0 3 Exhaust gas. The gas discharged from each space 301, 302, 303 is discharged, for example, to a space outside the device. The gas discharged from each of the spaces 301, 302, and 303 may be purified and reused as a purge gas. By reusing the gas, the consumption of the purge gas (helium gas in this example) can be reduced.

In the exposure apparatus 100 of this example, helium gas (He) is supplied to the space 301 inside the lens barrel 169 of the projection optical system PL by the first gas supply mechanism 310, and the second gas is supplied to the second gas supply mechanism 310. The supply mechanism 311 supplies a nitrogen gas (N ₂ ) to the space 302 where the reticle R is arranged and the space 303 where the wafer W is arranged. That is, different types of gases are supplied to the space 302 in the projection optical system PL and the spaces 303 and 304 adjacent to the space 302.

Further, of the plurality of optical members (optical elements) constituting the projection optical system PL, the optical element 350 disposed at the uppermost stage on the reticle R side and the optical element disposed at the lowermost stage on the wafer W side The seal structure using the above-described magnetic fluid is used for each of the above-mentioned structures. That is, the optical element 350 is arranged at the boundary between the space 301 inside the projection optical system PL and the space 302 where the reticle R is arranged, and the seal structure shown in FIGS. It is supported by the support portion 35 having the following. Similarly, the optical element 351 is also arranged at the boundary between the space 301 inside the projection optical system PL and the space 303 where the wafer W is arranged, and is shown in FIGS. It is supported by a support portion 355 having a sealing structure using a magnetic fluid.

In the exposure apparatus of this example, the boundary between the space 301 in the projection optical system PL and the space 302 in which the reticle R is arranged, and the space 301 in the projection optical system PL and the wafer W are arranged. Since each of the boundaries with the space 303 is sealed using a magnetic fluid, gas leakage through those boundaries is prevented. Therefore, due to the high sealing performance, each space 301, 302, 303 on the optical path of the exposure light is stably filled with a high-purity and high-purity nitrogen gas or a nitrogen gas. In addition, the deformation of the optical elements 350 and 351 due to the seal is small, and the optical characteristics are improved. Here, the optical elements 350 and 351 are formed of parallel flat plates (parallel plane plates) having surfaces parallel to each other. In addition, by adjusting the posture and position of the optical elements 350 and 351, it is possible to correct local aberration (such as distortion that is not rotationally symmetric) of the exposure light. In the present example, since the seal structure using a magnetic fluid is used in the support portion 355 of the optical elements 350 and 351, the magnetic fluid as the seal member and the object are not used. The frictional resistance between them is small, and the shape of the magnetic fluid layer changes easily. Therefore, restrictions on the postures of the optical elements 350 and 351 are small, and the positions and postures of the optical elements 350 and 351 can be easily adjusted. From this point, the optical characteristics can be improved.

As described above, according to the exposure apparatus 100 of the present example, gas leakage in the space on the optical path of the exposure light is prevented and the optical performance is improved, so that the exposure accuracy is improved. be able to.

Note that, in the above example, a sealing structure using a magnetic fluid was used for the optical members disposed at the entrance and exit of the exposure light in the projection optical system PL. Similarly, for optical members placed at the entrance or exit of the exposure light for casing (for example, casings 161, 162; see Fig. 9), a seal using a magnetic fluid is used. A structure may be used. Also in this case, gas leakage in the space inside each casing is prevented, and the optical characteristics are improved.

As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but it is needless to say that the present invention is not limited to the examples. It is obvious that those skilled in the art can come up with various modified examples or modified examples within the scope of the technical idea described in the patent claims. It is understood that it belongs to the target range.

For example, the optical members supported by the seal structure using a magnetic fluid are not limited to parallel flat plates, but various optical members used in optical devices, such as curved lenses, beam splitters, and dichroic mirrors, can be applied. It is. Further, the support structure is not limited to the structure shown in the above-described embodiment, and is appropriately determined according to the installation space of the optical member and the accuracy of requesting the characteristics of the optical member.

Also, when a magnetic fluid layer is provided between the optical member and the support portion, the magnetic fluid layer is provided on one surface of the optical member. A step may be provided at a portion in contact with the magnetic fluid layer. This technique is advantageous in reliably supporting the optical member when the optical surface having the optically effective area is a curved surface.

Further, a configuration may be adopted in which a yoke is arranged for a magnet for holding the magnetic fluid layer to improve the magnetic force.

Further, as a material of a portion in contact with the optical member in the supporting portion, such as the above-described lens pressing member, a resin or a metal member which has been subjected to a chemical clean measure is preferably used. In addition, by using a material that does not easily generate thermal distortion, such as invar, it is possible to prevent the pedestal from being deformed due to the generation of heat, and to suppress the occurrence of distortion in the optical element and disturbance of the attitude of the optical element. it can.

Further, in order to remove the light absorbing substance from the optical path, it is preferable to perform a treatment for reducing the amount of outgas from the surface of the structural material in advance. For example, (1) the surface area of the structural material is reduced, (2) the surface of the structural material is polished by a method such as mechanical polishing, electrolytic polishing, puff polishing, chemical polishing, or GBB (Glass Beads Blasting). (3) Clean the surface of the structural material by means such as ultrasonic cleaning, spraying a fluid such as clean dry air, or vacuum degassing (baking). ) There are methods such as minimizing the installation of electric wire coating materials containing hydrocarbons and halides, sealing members (such as o-rings), and adhesives in the optical path space as much as possible.

In addition, the casing that forms the cover of the wafer operation section from the illumination system chamber (a cylindrical body or the like is also possible), and the pipe that supplies the permeable gas is made of a material with low impurity gas (degassing), such as stainless steel. It is desirable to form with various polymers such as titanium alloy, ceramics, tetrafluoroethylene, tetrafluoroethylene-terfluoro (alkyl vinyl ether), or tetrafluoroethylene-hexafluoropropene copolymer.

Similarly, it is desirable that the cables for supplying electric power to the drive mechanisms (reticle blinds, stages, etc.) in each housing are also covered with the above-mentioned material having a small amount of impurity gas (degassing).

It is apparent that the present invention can be applied not only to a scanning exposure type projection exposure apparatus, but also to a batch exposure type (stepper type) projection exposure apparatus. Be prepared for these The projection optical system may be not only a catadioptric system but also a dioptric system or a reflective system. Further, the magnification of the projection optical system may be not only a reduction magnification but also an equal magnification or an enlargement.

Further, as the present invention is an energy beam, A r F or when using the excimer laser beam (wavelength 1 9 3 nm), K r 2 laser beam (wavelength 1 4 6 nm), A r 2 laser beam (wavelength: 1 2 6 nm), and can be applied to vacuum ultraviolet light having a wavelength of about 200 nm to 100 nm, such as a harmonic of a YAG laser or a harmonic of a semiconductor laser.

In recent years, an exposure apparatus using an immersion method has been proposed to secure a wide depth of focus. In the immersion method, the space between the lower surface of the projection optical system and the substrate surface is filled with a predetermined liquid (water, organic solvent, etc.) as a fluid to form an immersion area, and the wavelength of the exposure light in the liquid is adjusted. Is used to improve the resolution by using lZn in the air (n is the refractive index of the liquid, usually about 1-2 to 1.6), and to increase the depth of focus by about n times. is there. The above-mentioned liquid immersion area supplies and recovers liquid using a nozzle member having a liquid supply port and a liquid recovery port. However, a gap between the nozzle member and the projection optical system and a projection optical system are provided. If a liquid enters the system, the housing (barrel) that holds the optical members that make up the projection optical system may crack. Therefore, the fluid seal mechanism described in the present embodiment may be provided in the gap between the nozzle member and the projection optical system.

In the exposure apparatus using the immersion method, a liquid is supplied between the lower surface of the projection optical system and the wafer W. That is, the external space 13 of the optical device described in each embodiment becomes a liquid atmosphere. As described above, even when the liquid is supplied to the external space 13 of the optical device and a liquid atmosphere is formed, as described in each embodiment, the fluid seal mechanism is provided between the optical member 14 and the housing 12. By providing the liquid, it is possible to prevent the liquid from entering the housing 12, prevent a predetermined gas from leaking from the housing 12, and prevent the leaked predetermined gas from entering the liquid. .

In the case where the laser light source 1 2 0 oscillates F ₂ laser, the F ₂ laser beam is not transmitted through water, as the liquid, that can transmit the _2, single laser light, for example perfluorinated capo Rie one ether (PFPE) or a fluorinated fluid such as a fluorinated oil may be used. In this case, a portion of the housing of the projection optical system that comes into contact with the liquid is subjected to lyophilic treatment by forming a thin film of a substance having a molecular structure with a small polarity, such as fluorine. In addition, as a liquid, it has the transparency to the exposure light EL and refracts as much as possible. It is also possible to use a material that has a high efficiency and is stable against the photoresist applied to the projection optical system PL and the surface of the substrate P (for example, cedar oil).

Further, when the laser light source 120 oscillates an ArF excimer laser light (wavelength: 193 nm), pure water (water) can be used. The refractive index n of pure water (water) is said to be about 1.44, and in the case of ArF excimer laser light, it is as short as 1Zn on the substrate P, that is, about 134 nm. High resolution is obtained by wavelength conversion. Furthermore, since the depth of focus is expanded to about n times, that is, about 1.44 times as compared to that in the air, when it is sufficient to secure the same depth of focus as when using it in the air, projection The numerical aperture of the optical PL can be further increased, and the resolution is also improved in this regard. When the liquid immersion method is used as described above, the numerical aperture NA of the projection optical system may be 0.9 to 1.3. When the numerical aperture NA of the projection optical system is increased as described above, the imaging effect may be degraded by the polarization effect of the randomly polarized light conventionally used as the exposure light. It is desirable to use. In that case, linearly polarized illumination is performed according to the longitudinal direction of the line pattern of the mask (reticle) line 'and' space pattern. From the mask (reticle) pattern, the S-polarized component (TE polarized component), That is, it is preferable that a large amount of diffracted light of the polarization component along the longitudinal direction of the line pattern is emitted. When the space between the projection optical system PL and the resist applied to the surface of the substrate P is filled with liquid, the space between the projection optical system PL and the resist applied to the surface of the substrate P is air (gas). Since the transmittance of the S-polarized light component (TE-polarized light component), which contributes to the improvement of the contrast, on the resist surface is higher than that in the case where it is satisfied, the numerical aperture NA of the projection optical system is set to 1.0. Even in such cases, high imaging performance can be obtained. In addition, a phase shift mask, an oblique incidence illumination method (particularly, a dipole illumination method) adapted to the longitudinal direction of a line pattern as disclosed in Japanese Patent Application Laid-Open No. 6-188169, etc. may be appropriately combined. More effective.

For example, using an ArF excimer laser as the exposure light, and using a projection optical system with a reduction ratio of about 1/4, a fine line 'and' space pattern (for example, a line of about 25 to 50 nm and ' When exposing the 'space' on the wafer W, depending on the mask structure (eg, fineness of chromium or thickness of chromium), the Wave guide Due to this effect, the mask acts as a polarizing plate, and more S-polarized component (TE polarized component) diffracted light is emitted from the mask than P-polarized component (TE polarized component) diffracted light, which lowers contrast. Although it is desirable to use the linearly polarized illumination described above, even if the mask is illuminated with randomly polarized light, high resolution performance can be obtained even when the numerical aperture NA of the projection optical system is as large as 0.9 to 1.3. be able to. When a very fine line-and-space pattern on a mask is exposed on a wafer, the P-polarized component (TM-polarized component) becomes larger than the S-polarized component (TE-polarized component) due to the Wire grid effect. For example, an ArF excimer laser is used as the exposure light, and a line-and-space pattern larger than 25 nm is formed on the wafer using a projection optical system with a reduction ratio of about 1Z4. In the case of exposure, the diffracted light of the S-polarized component (TE-polarized component) is emitted from the mask M more than the diffracted light of the P-polarized component (TM-polarized component), so the numerical aperture of the projection optical system PL Even when NA is as large as 0.9 to 1.3, high resolution performance can be obtained.

Further, in addition to linearly polarized light (S-polarized light) adapted to the longitudinal direction of the line pattern of the mask (reticle), as described in Japanese Patent Application Laid-Open No. 6-53210, the optical axis is adjusted. It is also effective to use a combination of a polarized illumination method that linearly polarizes light in the tangential (circumferential) direction of the center circle and an oblique illumination method. In particular, when a mask (reticle) pattern includes not only a line pattern extending in a predetermined direction but also line patterns extending in a plurality of different directions, the same applies to Japanese Patent Application Laid-Open No. 6-53120. As disclosed, the combined use of the polarized illumination method and the annular illumination method, which linearly polarizes in the tangential direction of a circle centered on the optical axis, makes it possible to achieve high resolution even when the numerical aperture NA of the projection optical system is large. ^ Imaging performance can be obtained.

In the present embodiment, an optical element is attached to the tip of the projection optical system PL, and this lens can be used to adjust the optical characteristics of the projection optical system PL, for example, aberrations (such as spherical aberration and coma aberration).

Also, when applying an exposure apparatus using the immersion method to a batch exposure type, for example, use a projection optical system as a refraction system with a magnification of 1/8 and at least two patterns on the wafer W. A step-and-stitch method of transferring images with partial overlap may be used. Further, the application of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, For example, the present invention can be widely applied to an exposure apparatus for a liquid crystal for exposing a liquid crystal display element pattern to a square glass plate and an exposure apparatus for manufacturing a thin film magnetic head.

When a linear motor is used for the wafer stage / reticle stage, either an air levitation type using an eye bearing or a magnetic levitation type using Lorentz force or reactance force may be used. The stage may be a type that moves along a guide or a guideless type that does not have a guide.

When a planar motor is used as the stage driving device, one of the magnet unit (permanent magnet) and the armature unit is connected to the stage, and the other of the magnet unit and the armature unit is connected to the stage moving surface (base). ).

The reaction force generated by the movement of the wafer stage is mechanically released to the floor (ground) using a frame member, as described in JP-A-8-166475. Is also good. The present invention is also applicable to an exposure apparatus having such a structure.

Also, the reaction force generated by the movement of the reticle stage may be mechanically released to the floor (ground) using a frame member as described in JP-A-8-330224. . The present invention is also applicable to an exposure apparatus having such a structure.

As described above, the exposure apparatus of the embodiment of the present invention performs various subsystems including each component listed in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Manufactured by assembling. Before and after this assembly, adjustments to achieve optical accuracy for various optical systems, adjustments to achieve mechanical accuracy for various mechanical systems, and various electrical The system will be adjusted to achieve electrical accuracy. The process of assembling the exposure apparatus from the various subsystems includes mechanical connections, wiring connections of electric circuits, and piping connections of pneumatic circuits among the various subsystems. It goes without saying that there is an assembly process for each subsystem before the assembly process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustments are made to ensure various precisions of the entire exposure apparatus. It is desirable to manufacture the exposure equipment in a clean room where temperature and cleanliness are controlled. Good.

Then, the wafer exposed as described above undergoes a developing step, a pattern forming step, a bonding step, packaging, and the like, whereby an electronic device such as a semiconductor element is manufactured. Industrial potential

The present invention relates to an optical device, comprising: a space formed on an optical path of an energy beam and supplied with a predetermined gas; an optical member arranged at a boundary between the space and another space; A supporting portion that has a facing surface facing the peripheral portion of the optical member, and that supports the peripheral portion of the optical member in a state where a gap is formed between the facing surface and the peripheral portion of the optical member; Since a fluid seal mechanism is provided between the peripheral portion of the member and the facing surface of the support portion, the space to which a predetermined gas is supplied and the external space can be provided without deteriorating the optical characteristics of the optical member. With this, fluid (gas or liquid) can be prevented from entering or leaking.

Claims

The scope of the claims

1. An optical device,

A space formed on the optical path of the energy beam, and supplied with a predetermined gas; and an optical member disposed at a boundary between the space and another space;

A support portion that has a facing surface facing the peripheral portion of the optical member, and supports the peripheral portion of the optical member in a state where a gap is formed between the facing surface and the peripheral portion of the optical member; A fluid seal mechanism disposed between a peripheral portion of the optical member and an opposing surface of the support portion.

2. The optical device according to claim 1, wherein

The fluid seal mechanism includes: a magnetic fluid layer provided between a peripheral portion of the optical member and the facing surface;

And a magnet for holding the magnetic fluid layer at a predetermined position.

3. The optical device according to claim 2, wherein

For the magnetic fluid layer, a fluorine-based base liquid is used.

4. The optical device according to claim 2, wherein

The optical member includes: an optical surface having an optical effective area; a peripheral surface in the same plane as the optical surface; and a side surface of the optical member.

The magnetic fluid layer is disposed so as to contact at least one of a peripheral surface of the optical member and a side surface of the optical member.

5. The optical device according to claim 4, wherein

The magnetic fluid layer is disposed so as to be in contact with a peripheral surface at a peripheral portion of the optical member.

The peripheral surface has a portion in contact with the magnetic fluid layer has a different surface characteristic from other portions. Is managed.

6. The optical device according to claim 4, wherein

The magnetic fluid layer is disposed so as to contact a side surface of the optical member,

The side surface of the side surface is processed to have a surface characteristic different from that of another portion in contact with the magnetic fluid layer.

7. The optical device according to claim 2, wherein

The periphery of the optical member has surfaces parallel to each other,

The support portion is in contact with one of the surfaces parallel to each other, and supports three peripheral portions of the optical member at substantially equal intervals; and

Three pressing members arranged at positions corresponding to the three seats, respectively, in contact with the other surfaces parallel to each other, and sandwiching a periphery of the optical member together with the three seats,

The magnetic fluid layer contacts at least one of the parallel surfaces.

8. The optical device according to claim 2, wherein

The magnet is embedded in a part of the facing surface.

9. The optical device according to claim 2, wherein

The magnet is arranged in a convex shape on the facing surface.

10. The optical device according to claim 1, wherein

A gas different from the predetermined gas is supplied to the other space.

1 1. An exposure apparatus,

An optical system according to claim 1, wherein at least one of an illumination system that illuminates the mask on which the pattern is formed with an energy beam and a projection optical system that transfers the pattern of the mask onto a substrate is provided.

12. The exposure apparatus according to claim 11, wherein

The optical member is an optical element facing the substrate, among a plurality of optical elements constituting the projection optical system,

The space is a space in the projection optical system,

The other space is a space between the optical element and the substrate.

13. The exposure apparatus according to claim 12, wherein

A first gas supply mechanism for supplying a first gas to a space in the projection optical system; and a second gas different in type from the first gas in a space between the optical element and the substrate. And a second gas supply mechanism for supplying.

1 4. The exposure apparatus according to claim 11, wherein

The optical member is an optical element arranged on the mask side among a plurality of optical elements constituting the projection optical system,

The space is a space in the projection optical system,

The other space is a space between the optical element and the mask.

15. The exposure apparatus according to claim 14, wherein

A first gas supply mechanism for supplying a first gas to a space in the projection optical system; and a space between the optical element and the mask, a second gas different in type from the first gas. And a second gas supply mechanism for supplying.

16. The exposure apparatus according to claim 12, wherein

The other space is a liquid atmosphere.

1 7. A device manufacturing method,

And transferring the device pattern formed on the mask onto the substrate using the exposure apparatus according to claim 11.

18. A device manufacturing method,

And transferring the device pattern formed on the mask onto the substrate by using the exposure apparatus according to claim 16.