JP2005062438A - Method for manufacturing projection optical system and projection optical system, and projection aligner having the projection optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously achieve the higher accuracy position adjustment between lens barrel units of a projection optical system and the higher hermeticity of a concentration portion of the lens barrel units. <P>SOLUTION: A first surface 14a of a flanged section 14 of the lens barrel unit B is placed on a second surface 15a of a flanged section 15 and is subjected to position adjustment in the state of placing a pressing member 52 and a sealing material 54 on a flanged section 15 of the lens barrel unit C and after the completion of the position adjustment, the flanged sections 14 and 15 of both the lens barrel units B and C are fixed and connected to each other by bolts 12a and nuts 16a. At this time, the pressing member 52 and the sealing material 54 do not contact the flanged section 14 at all and do not affect the position adjustment. The pressing member 52 is then tightened and fixed by a bolt 13a and a nut 17a to the first surface 14a of the flanged section 14. Accompanying the same, the sealing material 54 is compressed by the pressing member 52 and is pressed to the first surface 14a of the flanged section 14 and the outer peripheral surface 15b of the flanged section 15 and the higher hermeticity is achieved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes a projection optical system used in a process of forming a fine pattern required in a process of manufacturing an electronic device such as a semiconductor integrated circuit, a liquid crystal display, an imaging device, and a magnetic head, a manufacturing method thereof, and the projection optical system. The present invention relates to a projection exposure apparatus.

  Formation of a fine pattern necessary for manufacturing an electronic device such as a semiconductor integrated circuit or a liquid crystal display is performed using a projection exposure apparatus. A projection optical system mounted on a projection exposure apparatus uses a circuit pattern on a reticle (photomask or mask) on which a circuit pattern to be formed is drawn in proportion to about 4 to 5 times, and a substrate to be exposed such as a wafer. Projection exposure on top. The circuit pattern subjected to the projection exposure selectively exposes a photoresist (photosensitive resin) applied to the wafer surface. The wafer is subsequently developed, and only the photosensitive portion (or non-photosensitive portion) in the photoresist is selectively removed to transfer the circuit pattern on the reticle.

The resolution (R) of the projection optical system is generally proportional to the exposure wavelength (λ) and inversely proportional to the numerical aperture (NA) (R = k · λ / NA k: proportional constant). Therefore, in order to cope with the miniaturization of the semiconductor integrated circuit, the wavelength of the light source of the projection exposure apparatus has been shifted to a shorter wavelength side. At present, the wavelength is mainly 248 nm of KrF (krypton fluorine) excimer laser, but 193 nm of shorter wavelength ArF (argon fluorine) excimer laser is also entering the practical stage. Further, a projection exposure apparatus using a light source in a so-called vacuum ultraviolet region such as an F ₂ (fluorine) laser having a shorter wavelength of 157 nm or an Ar ₂ (argon molecule) laser having a wavelength of 126 nm is also proposed. It has been broken.

  In parallel with the shortening of the wavelength, the numerical aperture has been increased, and the projection optical system has been enlarged accordingly. The current projection optical system has a total length exceeding 1 m, and 20 or more lenses are loaded therein. Some lenses have a large diameter of about 250 mm.

  By the way, in order for the projection optical system to exhibit a predetermined resolution, the lenses and reflecting mirrors constituting the projection optical system need to be correctly arranged with a predetermined positional relationship. However, it is said that it is actually difficult to hold such a large and large number of lenses in a single lens barrel having a long overall length with high positional accuracy. Therefore, in a recent projection optical system, the lens barrel is divided into several in the optical axis direction, a lens is installed in each lens barrel unit, and each lens barrel unit is combined into one lens barrel. Adopting the unit method has become the mainstream.

  In the lens barrel unit method, the position adjustment between the lens barrel units is required when assembling the projection optical system. In order to suppress the aberration of the projection optical system within a practical range, it is necessary to reduce the positional accuracy thereof to, for example, about 1 μm or less (perform with high accuracy).

  When connecting the lens barrel units, even if the end surfaces of the lens barrel units are in direct contact with each other or indirectly through spacers (washers, shims), the end surfaces of the lens barrel units and the spacers A certain degree of airtightness can be secured between the lens barrel units by surface processing such as polishing.

However, since vacuum ultraviolet light having a wavelength of 200 nm or less is vigorously absorbed by oxygen or water vapor in the atmosphere, the optical path space of an exposure apparatus that uses vacuum ultraviolet light (the optical path space of an illumination optical system or the optical path space of a projection optical system ( Etc.) must be replaced with nitrogen gas or a rare gas (hereinafter referred to as “low absorption gas”) that does not absorb exposure light. For example, in an exposure apparatus that uses an F ₂ laser with a wavelength of 157 nm as a light source, it is said that it is necessary to keep the residual oxygen concentration and residual water vapor concentration below about 1 ppm in most of the optical path from the laser light source to the wafer. .

  In order to achieve this, the projection optical system lens barrel is made highly airtight, and a low absorption gas is supplied to the exposure optical path space inside it. It is necessary to prevent the outside air from entering.

  Further, even in an exposure apparatus that uses a light source having a wavelength longer than 200 nm, if an organic substance is present in the exposure optical path, even if it is in a very small amount, a chemical reaction is caused by the energy of the exposure light and the surface of the optical system. It accumulates in the water and causes fogging of the optical system. Therefore, even in an exposure apparatus that uses a long-wavelength light source, it is extremely important that the projection optical system is hermetically sealed and no impurities are mixed therein.

  As a known highly airtight method, for example, there is a method adopted for airtightness between cylindrical members of a vacuum apparatus. According to this method, a sealing material such as an O-ring is interposed between the opposing end surfaces of the flange of the cylindrical member, and when the both flanges are connected by bolts and nuts, the sealing material is pressed by the end surface of the flange, A sealing material is deformed and adhered to the end face of the tube to make it airtight. However, when this is adopted in the lens barrel unit method, the following inconvenience occurs.

  That is, when sealing is performed by interposing a sealing material between the end faces of the flange, when the position is adjusted and the sealing is performed, the deformation stress of the sealing material generated in the process of sealing is caused from the end face of the flange to the lens barrel. There is a possibility that the position adjustment once performed may be broken by acting not only in the axial direction of the unit but also in a direction perpendicular to the axial direction. Further, if the position is adjusted after airtightness, the position adjustment must be performed against the deformation stress of the sealing material generated in the process of airtightness, and accurate position adjustment itself is difficult. Eventually, the position is adjusted and the airtightness is performed (position adjustment and airtightness are performed almost simultaneously), but due to the presence of the deformation stress of the sealing material, the above-mentioned position adjustment accuracy (for example, It is difficult to achieve both of about 1 μm or less and airtightness (for example, about 1 ppm or less).

  The present invention has been made in view of the above circumstances, and is capable of achieving both high-accuracy position adjustment between lens barrel units and high airtightness between lens barrel units. It is an object to provide a method, a projection optical system, and a projection exposure apparatus having the projection optical system.

  The projection optical system manufacturing method of the present invention that achieves the above-described object provides a projection optical system that constitutes the projection optical system (1) by connecting a plurality of lens barrel units (A, B, C, D, E) to each other. In the manufacturing method, of the plurality of lens barrel units, the first surface (14a) of the first lens barrel unit (for example, the lens barrel unit B) and the second surface (for example, the lens barrel unit C) of the second lens barrel unit (for example, the lens barrel unit C). 15a) are opposed to each other, the position between the first lens barrel unit and the second lens barrel unit is adjusted, and the position between the first lens barrel unit and the second lens barrel unit is adjusted. After that, in order to ensure airtightness between the first surface (14a) and the second surface (15a), an airtight member between the first lens barrel unit and the second lens barrel unit. It is characterized by attaching.

The projection optical system of the present invention includes a plurality of lens barrel units (A, B, C, D, E), wherein the plurality of lens barrel units are connected to each other. A first lens barrel unit (for example, lens barrel unit B) having a first surface (14a), and a second lens surface having a second surface (15a) facing the first surface (14a) among the plurality of lens barrel units. After adjusting the position between two lens barrel units (for example, the lens barrel unit C) and the first lens barrel unit and the second lens barrel unit, the airtightness between the first surface and the second surface In order to ensure the performance, an airtight member attached between the first lens barrel unit and the second lens barrel unit is included.

  In the manufacturing method of the projection optical system and the projection optical system described above, “ensuring airtightness” means that the inside of the lens barrel unit is kept at a slightly higher pressure (positive pressure) than the outside (positive pressure). This is not to prevent the gas from flowing into the inside of the lens barrel unit from the outside by leaking the gas from the outside to the outside, regardless of the pressure inside the lens barrel unit, and the first surface of the first lens barrel unit. This means that gas does not flow from the outside into the lens barrel unit from between the second surface of the two lens barrel units.

  According to the projection optical system manufacturing method and the projection optical system of the present invention, both high-accuracy position adjustment and high airtightness can be achieved.

  The hermetic member may prevent the first lens barrel unit and the second lens barrel unit from affecting the positional relationship between the adjusted first lens barrel unit and the second lens barrel unit. It is preferable that it is attached from the outside.

  Here, “so as not to affect the positional relationship between the adjusted first lens barrel unit and the second lens barrel unit” means that the positional adjustment between the lens barrel units once performed is not lost. In addition, “attached from the outside of the first lens barrel unit and the second lens barrel unit” means, for example, an airtight outer side of the first lens barrel unit and the second lens barrel unit. It means that the space between the first surface and the second surface is hermetically sealed by applying the adjusting member. As the airtight member, for example, there is an O-ring, and in addition, an adhesive, grease, and the like are included.

  The position adjustment between the lens barrel units is preferably performed by sliding the first lens barrel unit with respect to the second lens barrel unit.

  The first lens barrel unit has a first flange portion (14) formed with the first surface, and the second lens barrel unit is formed with the second surface and of the first flange portion. It is preferable to have the 2nd flange part (15) formed with the outer diameter smaller than an outer diameter.

  The airtight member is deformable and has an annular airtight component (54) having a size between the outer diameter of the first flange portion (14) and the outer diameter of the second flange portion (15). And a pressing member (52) for pressing the airtight component against the first surface (14) of the first lens barrel unit and the side surface (15b) of the second flange portion (15). Is preferred.

  It is preferable that the side surface (15b) of the second flange portion has a tapered surface that is inclined so that the outer diameter gradually increases as the distance from the second surface (15) increases.

  Before the first surface (14) of the first lens barrel unit (lens barrel unit B) and the second surface (15) of the second lens barrel unit (lens barrel unit C) are opposed to each other, the taper surface After the airtight component (54) is arranged in (15b) and the position between the first lens barrel unit and the second lens barrel unit is adjusted, the airtight component is formed by the pressing member (52). Is preferably pressed against the first surface of the first lens barrel unit and the side surface of the second flange portion.

  The pressing member presses the first flange portion (14) of the first lens barrel unit (lens barrel unit B) and the second flange portion (15) of the second lens barrel unit (lens barrel unit C). Is preferably performed after fastening with fastening members (13a, 17a).

  When attaching the airtight member to at least one of the first lens barrel unit (lens barrel unit B) and the second lens barrel unit (lens barrel unit C), the first lens barrel unit and the second lens barrel. It is preferable to provide a stress reduction mechanism that reduces the stress generated in the unit so that the stress does not affect the positional relationship between the first lens barrel unit and the second lens barrel unit.

  The stress reduction mechanism is preferably a groove (63, 65) provided in at least one of the first flange portion (14) and the second flange portion (15).

  The stress reduction mechanism is preferably a groove (64, 66) provided in at least one of the first surface (14a) and the second surface (15a).

  An exhaust connector (67) is connected to a space formed by the groove (64) provided on the first surface and the groove (65) provided on the second surface, and the exhaust connector is interposed therebetween. It is preferable to exhaust the gas flowing into the space.

  The projection exposure apparatus of the present invention is the projection exposure apparatus for exposing and transferring a predetermined pattern onto the substrate (87) to be exposed via the projection optical system (1). It is equipped with the projection optical system according to one item.

  According to the projection exposure apparatus of the present invention, exposure with high transmittance and low transmittance reduction, high exposure energy on the wafer surface as the substrate to be exposed, high throughput, and high imaging performance. An apparatus can be realized.

  According to the projection optical system manufacturing method of the present invention, the first mirror of the first lens barrel unit and the second surface of the second lens barrel unit are opposed to each other among the plurality of lens barrel units. In order to secure the airtightness between the first surface and the second surface after adjusting the position between the tube unit and the second lens barrel unit, the space between the first lens barrel unit and the second lens barrel unit. Since the airtight member is attached to the lens, it is possible to achieve both high-accuracy position adjustment and airtightness of the connecting portion between the lens barrel units.

  According to the projection optical system of the present invention, among the plurality of lens barrel units, the first lens barrel unit having the first surface, the second lens barrel unit having the second surface facing the first surface, After adjusting the position between the first lens barrel unit and the second lens barrel unit, in order to ensure airtightness between the first surface and the second surface, the first lens barrel unit and the second lens barrel In particular, a connecting portion between the lens barrel units for a projection optical system composed of a plurality of lens barrel units premised on use at an exposure wavelength in the vacuum ultraviolet region. This makes it possible to achieve both high-accuracy position adjustment and airtightness, improve the purity of the low-absorbency gas in the projection optical system, and thereby improve the transmittance of the projection optical system. A high projection optical system can be realized.

  Further, according to the exposure apparatus of the present invention, by mounting the above-described projection optical system, high transmittance and low transmittance decrease, high exposure energy can be obtained on the wafer surface that is the substrate to be exposed, and high throughput is achieved. In addition, an exposure apparatus that can obtain high imaging performance can be realized.

  A first embodiment of the projection optical system of the present invention will be described below with reference to FIGS.

  FIG. 1A is a top view of the projection optical system 1 of the first embodiment, and FIG. 1B is a side view thereof. The projection optical system 1 connects five lens barrel units of a lens barrel unit A, a lens barrel unit B, a lens barrel unit C, a lens barrel unit D, and a lens barrel unit E in series along an optical axis AX ( Formed). Each barrel unit A, B, C, D, E includes an optical member such as a lens 40 indicated by a broken line in the drawing, and a pattern (reticle pattern not shown) is provided above the projection optical system 1 by the action of these optical members. Is formed under the projection optical system 1.

  Flange portions are formed at the upper and lower ends of each lens barrel unit (at the lower end in the uppermost lens barrel unit A and at the upper end in the lowermost lens barrel unit E). That is, a flange portion 6 is formed at the lower end of the uppermost barrel unit A, and a flange portion 7 is formed at the upper end of the next barrel unit B connected to the barrel unit A. A flange portion 14 is formed at the lower end of the barrel unit B, and a flange portion 15 is formed at the upper end of the next barrel unit C connected to the barrel unit B. A flange portion 22 is formed at the lower end of the barrel unit C, and a flange portion 23 is formed at the upper end of the next barrel unit D connected to the barrel unit C. A flange portion 31 is formed at the lower end of the barrel unit D, and a flange portion 32 is formed at the upper end of the lowermost barrel unit E to which the barrel unit D is connected.

  The lower surface and upper surface of these flange portions 6, 7, 14, 15, 22, 23, 31, 32 are surfaces perpendicular to the optical axis AX of the projection optical system 1. The lens barrel portion 3 and the flange portion 6 of the lens barrel unit A are integrally formed, for example, by cutting using a lathe. Similarly, the lens barrel portion 10 and the flange portions 7 and 14 of the lens barrel unit B are integrally formed by a lathe, for example. Similarly, the lens barrel portions 18 and 19 and the flanges 15 and 22 of the lens barrel unit C are integrally formed by a lathe, for example. As shown in FIG. 1B, the lens barrel units 28 and 25 of the lens barrel unit D and the lens barrel unit E are lens barrels whose diameters change in the middle through the stepped portions. Needless to say, the lens barrel portions 28 and 35 and the flanges 23, 31 and 32 can be integrally formed by cutting with a lathe as described above.

  The lens barrel units A and B are connected to each other via flange portions 6 and 7, and the flanges 6 and 7 are firmly fixed to each other by a headed bolt 4a and a nut 8a which are mechanical fixing members (fastening members). Is done. That is, the connection with the lens barrel units A and B is made by connecting the flanges 6 and 7 with a plurality of heads arranged at appropriate intervals along the periphery of the lens barrel portion 3 as shown in FIG. This is done by fixing with bolts 4a and nuts 8a.

  Similarly, with respect to the connection between the lens barrel unit B and the lens barrel unit C, a plurality of headed bolts 12a in which the flange portion 14 and the flange portion 15 are arranged at appropriate intervals along the periphery of the lens barrel portion 10 are also provided. And fixing by the nut 16a.

  Between the upper barrel portion 18 and the lower barrel portion 19 of the barrel unit C, an annular mounting flange 2 is formed as a mounting portion when the projection optical system 1 is loaded into the projection exposure apparatus. . As shown in FIG. 1A, the mounting flange 2 is formed with through holes 36a, 36b and the like used when the projection optical system 1 is fixed to the projection exposure apparatus.

Similarly, with respect to the connection between the lens barrel unit C and the lens barrel unit D, a plurality of headed bolts 20a and nuts that are arranged with the flange 22 and the flange 23 spaced at appropriate intervals along the periphery of the lens barrel portion 19 are also provided. For the connection between the lens barrel unit D and the lens barrel unit E, similarly, the flange 31 and the flange 32 are arranged at appropriate intervals along the periphery of the lens barrel portion 28. This is performed by fixing with a plurality of headed bolts 29a and nuts 33a.

  The flange portions 6, 7, 14, 15, 22, 23, 31, 32, and the headed bolts 4a, 12a, 20a, 29a and the nuts 8a, 16a, 24a, 33a, which are mechanical fixing means (fastening members). Constitutes a coupling mechanism for coupling the lens barrel units A, B, C, D, E to each other.

  An airtight mechanism is provided between the lens barrel units A, B, C, D, and E connected as described above.

  Hereinafter, as an example, an airtight mechanism between the lens barrel unit B and the lens barrel unit C and a method of assembling the lens barrel unit B and the lens barrel unit C (method of adjusting the position and airtight after connecting) This will be described in detail with reference to FIGS. 2 to 4A.

  First, the airtight mechanism will be described.

  FIG. 2 is an exploded perspective view showing the upper part of the lens barrel unit C and its associated parts before connection, and FIG. 4A is a partial sectional view of the airtight mechanism. As shown in FIG. 1B, the lens barrel unit C includes a lower lens barrel portion 19 and a flange 22. However, in FIG. 2, these lower lens barrel portions 19 and the like are omitted, and the mounting flange 2 and the like are omitted. Only the upper upper barrel portion 18 and the flange portion 15 are shown.

  A first surface 14 a is formed at the lower end of the flange portion 14. A second surface 15a is formed at the upper end of the flange portion 15 facing the first surface 14a (see FIG. 3A). The flange portion 15 is set to have a smaller diameter than the flange portion 14, and there is a portion that is not covered by the second surface 15 a of the flange portion 15 on the outer peripheral side of the first surface 14 a of the flange portion 14.

  As shown in FIG. 2, through holes 51 a and 51 b for inserting headed bolts 12 a and 12 b (see FIG. 1B) penetrating the flange portion 14 are circumferentially formed on the second surface 15 a of the flange portion 15. Are formed at equal intervals along. Nuts 16a and 16b are screwed onto the headed bolts 12a and 12b protruding from the through hole 51, whereby the flange portion 14 and the flange portion 15 are fixed and connected to each other. An annular pressing member 52 is disposed in a portion between the flange portion 15 and the flange portion 14 (a portion on the outer peripheral side of the first surface 14a that is not covered by the second surface 15a). The pressing member 52 is attached (fitted) to the flange portion 15 from above, and the headed bolts 13a and 13b penetrating the flange portion 14 (see FIGS. 1B and 3C). A plurality of through holes 53a and 53b for insertion are formed at equal intervals along the circumferential direction. As shown in FIGS. 1B and 3C, nuts 17a and 17b are screwed into portions of the bolts 13a and 13b protruding from the through holes 53a and 53b. The flange portion 14 is fixed to the first surface 14a (see FIG. 3A).

As shown in FIG. 4A, the outer peripheral surface 15b of the flange portion 15 has an outer diameter that is smaller at the upper portion and smaller toward the lower portion (the outer surface increases as the distance from the first surface 14a of the flange portion 14 increases). It is formed in a tapered shape (in order to increase the diameter). The inner peripheral surface of the pressing member 52 is formed in a taper shape in which the inner diameter is small at the intermediate portion and the inner diameter is expanded toward the lower portion so that the lower half 52a thereof is parallel to the outer peripheral surface 15b of the flange portion 15. The upper half 52b is formed in a tapered shape in which the inner diameter is small at the intermediate portion and the inner diameter is increased toward the upper portion so as to be separated from the outer peripheral surface 15b of the flange portion 15. That is, the inner peripheral surface of the pressing member 52 has an inner diameter that is the smallest at the intermediate portion thereof, and an inner diameter that is larger than the intermediate portion at the upper and lower portions thereof. The inner diameter (minimum inner diameter) of the intermediate portion of the pressing member 52 is larger than the outer diameter (minimum outer diameter) of the upper end portion of the flange portion 15, but smaller than the outer diameter (maximum outer diameter) of the lower end portion of the flange portion 15. It is set and allows the pressing member 52 to be attached (fitted) from above the flange portion 15, while preventing the pressing member 52 from being caught by the lower end portion of the flange portion 15 and falling off from the lower end portion.

  In the space surrounded by the outer peripheral surface 15b of the flange portion 15, the upper half 52b of the pressing member 52, and the flange portion 14, a sealing material 54 as an airtight component such as an O-ring is disposed for airtightness. The inner diameter of the sealing material 54 is set slightly larger than the outer diameter (minimum outer diameter) of the upper end portion of the flange portion 15.

  The outer peripheral surface 15b of the flange portion 15 described above, the pressing member 52, the lower half 52a, the upper half 52b of the inner peripheral surface of the pressing member 52, the sealing material 54, the bolts 13a and 13b, and the nuts 17a and 17b are connected to the lens barrel unit B. An airtight mechanism between the connecting portions with the lens barrel unit C is configured. Further, the pressing member 52 and the sealing material 54 in the airtight mechanism constitute an airtight member.

  When the projection optical system 1 of the present example uses vacuum ultraviolet light having an exposure wavelength of 200 nm or less, nitrogen gas or rare gas that absorbs less light than oxygen with respect to the exposure wavelength in the optical path. It is necessary to replace the gas with a gas (hereinafter referred to as “low absorption gas”). Further, even when exposure light having a wavelength longer than 200 nm is used, if there are contaminants such as organic matter in the optical path, the organic matter is chemically changed by the light energy of the exposure light and deposited on the lens surface, There is a risk of reducing the transmittance of the projection optical system 1.

  Therefore, as shown in FIG. 1B, the projection optical system 1 of this example includes, for example, a vent hole (not shown) in the lens barrel portion 10 of the lens barrel unit B and the lens barrel portion 28 of the lens barrel unit D. Gas piping connectors 11 and 26 are provided, and clean air that does not contain low-absorbing gas or organic matter is introduced into the projection optical system 1 through the gas piping connector 11 and the gas supply pipe 12 connected to the gas piping connector 11. On the other hand, the gas in the projection optical system 1 is discharged through a gas pipe connector 26 and a gas discharge pipe 27 connected to the gas pipe connector 26.

  Next, a method of assembling the lens barrel unit B and the lens barrel unit C (a method of adjusting the position and airtight after connecting) will be described in detail with reference to FIG.

  3A is a partial cross-sectional view showing a state before connection, FIG. 3B is a partial cross-sectional view showing a state during connection and fixing, and FIG. 3C is a partial cross-section showing an airtight state after connection. FIG.

  As shown in FIG. 3A, in the lens barrel portion 10 of the lens barrel unit B, the lens 41 has a lens holding mechanism 42a, so that its optical axis coincides with the center axis AXB of the lens barrel unit B. 42b. On the other hand, in the lens barrel portion 18 of the lens barrel unit C, the lens 43 is disposed via the lens holding mechanisms 44a and 44b so that the optical axis thereof coincides with the central axis AXC of the lens barrel unit C. . Between the lens barrel units B and C, that is, between the flange portion 15 of the lens barrel unit C and the flange portion 14 of the lens barrel unit B, a pressing member 52 and a sealing material 54 of an airtight mechanism are arranged. .

  As shown in FIG. 3B, the flange of the lens barrel unit B is placed on the second surface 15a of the flange portion 15 with the pressing member 52 and the sealing material 54 placed on the flange portion 15 of the lens barrel unit C. The first surface 14a of the part 14 is placed. At this time, the pressing member 52 is separated from the flange portion 14 in a state of being caught by the lower end portion of the flange portion 15, and does not contact the flange portion 14. Further, the sealing material 54 is also in a space between the outer peripheral surface 15 b of the flange portion 15 and the upper half 52 b of the inner peripheral surface of the pressing member 52, and does not contact the flange portion 14.

When connecting and fixing both barrel units B and C, first, the central axes of the barrel units B and C (
The optical axes AXB, AXC) need to be accurately aligned. That is, it is necessary to adjust the position between the lens barrel units B and C. For this position adjustment, for example, while measuring the side surface positions of the upper and lower barrel units B and C with a mechanical position sensor or an optical position sensor, one of the barrel units (for example, the barrel unit B) is measured. This is done by pushing and pulling the other barrel unit (for example, barrel unit C) and adjusting its position. That is, it is performed while sliding the first surface 14a of the flange portion 14 of the lens barrel unit B on the second surface 15a of the flange portion 15 of the lens barrel unit C. For this, for example, position adjustment accuracy of 1 μm or less is required. The first surface 14a is not in contact with the second surface 15a without sliding the first surface 14a of the flange portion 14 with respect to the second surface 15a of the flange portion 15 (the lens barrel unit B is replaced with the lens barrel unit). The first surface 14a and the second surface 15a may be brought into contact with each other after the positioning is performed in a state of being lifted with respect to C).

  After this position adjustment is completed, both barrel units B and C are fixed by the headed bolts 12a and 12b and the nuts 16a and 16b.

  Even in the coupled / fixed state shown in FIG. 3B, the space 60 in the lens barrel of the projection optical system 1 is substantially airtight with respect to the external space, but the first surface 14a of the flange portion 14 and the flange portion The air permeability through the space between the first surface 14a and the second surface 15a remains due to surface irregularities associated with the mechanical grinding or polishing of the 15 second surfaces 15a. In order to block the air permeability between the first surface 14a and the second surface 15a (to ensure the airtightness between the first surface 14a and the second surface 15a), FIG. C), the pressing member 52 is fastened and fixed to the flange portion 14 with the headed bolts 13a and 13b and the nuts 17a and 17b. Accordingly, the sealing material 54 is pressed by the pressing member 52 and pressed against the first surface 14 a of the flange portion 14 and the outer peripheral surface 15 b of the flange portion 15.

  As a result, as shown in detail in FIG. 4A, a part 61 of the surface of the sealing material 54 is in close contact with the first surface 14 a of the flange portion 14, and another part 62 is the outer peripheral surface 15 b of the flange portion 15. Close contact with. Thereby, the space between the first surface 14a and the second surface 15a is blocked from the outside of the lens barrel, and the internal space 60 of the lens barrel is blocked from the outside of the lens barrel, so that the internal space 60 is hermetically sealed.

  In the above description, the connection between the lens barrel unit B and the lens barrel unit C is performed. However, the lens barrel unit C and the lens barrel unit D are connected to each other between the connection portions of the lens barrel unit A and the lens barrel unit B. For the connecting portion between the lens barrel unit D and the connecting portion portion between the lens barrel unit E and the lens barrel unit E, the same position adjusting mechanism and airtight mechanism as described above are employed, and the same assembling method is employed. Detailed description is omitted.

  In FIG. 1B, reference numerals 5 a and 9 a are for fixing a pressing member constituting an airtight mechanism between the flange portion 6 of the lens barrel unit A and the flange portion 7 of the lens barrel unit B to the flange portion 6. The headed bolts and nuts, and reference numerals 20a and 24a fix the pressing member constituting the airtight mechanism between the flange portion 22 of the lens barrel unit C and the flange portion 23 of the lens barrel unit D to the flange portion 22. Headed bolts and nuts, and reference numerals 30a and 34a are used to fix a pressing member constituting an airtight mechanism between the flange portion 31 of the lens barrel unit D and the flange portion 32 of the lens barrel unit E to the flange portion 31. It is a headed bolt and nut.

  As described in the section of the problem to be solved by the invention, when the sealing material is interposed between the facing surfaces of the flange of the lens barrel unit so as to be airtight, the elastic deformation stress of the sealing material causes the flange from the surfaces. Therefore, it is difficult to connect and fix the lens barrel units while maintaining the positional relationship between them accurately or while accurately adjusting the positions.

On the other hand, in the airtight mechanism and assembly method of the projection optical system 1 of this example, the lens barrel unit B
As already described in the case of C, since the sealing material 54 is arranged without being in contact with the first surface 14a of the flange portion 14 of the upper barrel unit B at the time of position adjustment, both the barrel units B and C At the time of contact and sliding, a deformation stress cannot be generated in the sealing material 54, and the deformation stress of the sealing material 54 cannot deteriorate the accuracy of lens barrel position adjustment.

  Further, it is the both barrel unit B that fastens and fixes the pressing member 52 to the first surface 14a of the flange portion 14 with the headed bolts 13a and 13b and the nuts 17a and 17b, which are mechanical fixing members for airtightness. , C after the positional relationship is accurately adjusted and firmly fixed by the headed bolts 12a, 12b and nuts 16a, 16b. There is no error in the positional relationship.

  Similarly, between the lens barrel units A and B, between the lens barrel units C and D, and between the lens barrel units D and E adopting the same airtight mechanism and assembling method, both the lens barrel units are contacted and slid. Deformation stress cannot occur in the sealing material 54, and the deformation stress of the sealing material 54 cannot deteriorate the accuracy of lens barrel position adjustment. Further, no error occurs in the positional relationship between the lens barrel units after the position adjustment due to airtightness.

Therefore, according to this example, it is possible to realize an excellent airtight projection optical system having both high airtightness and highly accurate position adjustment, and for example, the oxygen (O ₂ ) concentration is suppressed to about 0.1 ppm or less. The water vapor (H ₂ O) concentration can be suppressed to 1 ppm to 2 ppm or less.

  In the above-described embodiment, for example, an O-ring is used as the sealing material 54, but this material is preferably a fluororesin such as Teflon, Viton, Kalrez (all are trade names), or the like.

  In addition, it is desirable to employ a material in which the surface of the O-ring is coated with a metal such as aluminum to reduce the amount of water generated from the O-ring.

  Further, a metal sealing material such as indium can be adopted as the sealing material 54.

  Each lens barrel unit A, B, C, D, E is fixed with headed bolts and nuts, but for airtightness between the flanges, a gap between the flanges ( For example, a method of pouring an adhesive or grease between the first surface 14a of the flange portion 14 and the second surface 15a of the flange portion 15 to make it airtight can be employed.

  The outer peripheral surface 15b of the flange portion 15 and the inner peripheral surface 52a of the pressing member 52 are formed in a tapered shape so that the diameter is large at the bottom and the diameter is small at the top. As shown in the modification of FIG. 4B, the outer peripheral surface 15b of the flange portion 15 and the lower half 52a of the inner peripheral surface of the pressing member 52 are tapered. Instead of forming, it may be formed in a straight shape in which the diameter does not change both above and below. The lower half 52b of the pressing member 52 is preferably tapered to press the sealing material 54.

  In the above-described embodiment and modification, the through holes 51a and 51b for inserting the headed bolts 12a and 12b are formed in the second surface 15a of the flange portion 15, and the headed bolts 12a and 12b of the flange portion 14 are also formed. A through hole (not shown) for inserting a through hole is formed. When the lens barrel unit B and the lens barrel unit C are connected, the headed bolts 12a and 12b are installed through these through holes, and are fixed by screwing the nuts 16a and 16b.

Therefore, the contact surface between the upper surface of the flange portion 14 and the headed bolts 12a and 12b (see FIGS. 3B and 4A), and the contact surface between the lower surface of the flange portion 15 and the nuts 16a and 16b (see FIG.
If there is air permeability in FIGS. 3 (B) and 4 (A)), outside air containing oxygen and water vapor enters the through holes 51a, 51b and the like from these contact surfaces. Then, the outside air passes between the first surface 14a of the flange 14 and the second surface 15a of the flange 15 in the optical path space of the projection optical system 1 due to the air permeability caused by the surface unevenness caused by the mechanical grinding or polishing of both surfaces. There is a risk of intrusion.

  However, the contact surfaces (fixed locations) between the upper surface of the flange portion 14 and the headed bolts 12a, 12b, and the contact surfaces (fixed locations) between the lower surface of the flange portion 15 and the nuts 16a, 16b are usually nuts 16a, Since a large pressing force (tightening force) generated when tightening 16b is applied, the oxygen concentration or the water vapor concentration in the optical path space of the projection optical system 1 is the reference value (described above) due to the air permeability of these contact surfaces. In reality, it is almost impossible to achieve this at about 1 ppm or less.

  However, the contact surface (fixed portion) between the upper surface of the flange portion 14 and the headed bolts 12a and 12b and the contact surface (fixed portion) between the lower surface of the flange portion 15 and the nuts 16a and 16b are relatively made of copper or the like. By placing a soft metal washer and deforming the washer with a large pressing force generated when tightening the nuts 16a and 16b, the gap existing in the fixed portion is eliminated (filled), and the higher degree Thus, it is possible to realize a tight airtightness and further reduce the oxygen concentration and the water vapor concentration in the optical path space.

  Further, instead of using a washer or in conjunction with the use of a washer, grease or an adhesive is applied around the headed bolts 12a and 12b, around the nuts 16a and 16b, or around the washer to further increase the airtightness. Can also be planned.

  By the way, regardless of whether or not such measures are taken to seal the bolts 12a and 12b and the nuts 16a and 16b, the through holes 51a and 51b formed in the flange portion 15 for passing the bolts 12a and 12b. A through hole (not shown) formed in the flange portion 14 is a slightly breathable space (hereinafter referred to as a “through hole space”) between the optical path space of the projection optical system 1.

  This through-hole space is difficult to efficiently perform gas replacement when replacing gas in the optical path space of the projection optical system 1. In order to perform gas replacement efficiently, it is necessary to improve the air permeability between the through hole space and the optical path space of the projection optical system 1.

  For this purpose, for example, a minute space is formed in the second surface 15a of the flange portion 15 or the first surface 14a of the flange portion 14, or the optical path space (space 60) and the flange are formed in the flange portion 15 or the flange portion 14. Ventilation holes connecting the through holes 51a and 51b of the portion 15 and the through holes (not shown) of the flange portion 14 can be provided to ensure the air permeability.

  Further, in the above-described embodiment, not only when the airtight mechanism and the assembly method are applied to airtightness and connection between the lens barrel unit C and the lens barrel unit D, but also the lens barrel unit A and the lens barrel unit. When applied to airtightness and connection between the lens barrel unit B and the lens barrel unit C, between the lens barrel unit D and the lens barrel unit E (all lens barrel units A, B, However, the present invention is not limited to this, and at least any one of the plurality of lens barrel units A, B, C, D, E is described. It may be applied to (for example, between the barrel unit B and the barrel unit C).

In the above-described embodiment, the projection optical system 1 is a refractive optical system including only the lens 40, but may be a catadioptric optical system including a reflecting mirror (mirror). In the case of the catadioptric optical system, there are cases where the optical axis AX of the projection optical system 1 is not only one, but a plurality of optical axes. In this case, the lens barrel units A, B, C, D, E Are connected along each optical axis.

  In the case of a catadioptric optical system, each optical axis is not always vertical. In the above description, the lens barrel units B and C have been described as being adjusted in a direction in which the optical axis is vertical, but this is a convenient measure for facilitating the description and is merely an example. Needless to say, there is no problem even if the lens barrel units A, B, C, D, and E are adjusted in the same posture as they are actually used, for example, horizontally or tilted. .

  In the above-described embodiment, the lens barrel units A, B, C, D, and E are fixed to each other and the pressing member 52 is fixed by a bolt and a nut. You may carry out by cutting a screw hole in the member to make, screwing a bolt with this screw hole, and tightening.

  Even if the connecting portions of the lens barrel units A, B, C, D, and E are hermetically sealed by the above mechanism, the uppermost optical element 40 (see FIG. 1B) of the projection optical system 1 is used. If the space between the lens barrel unit A and the space between the lowermost optical element 45 (see FIG. 1B) and the lens barrel unit E are not airtight, the projection optical system 1 as a whole is airtight. Not achieved. Therefore, for example, a flat plate optical element having a substantially airtight mechanism is employed as the seal mechanism at the top and bottom of the projection optical system 1, and this flat plate optical element is connected to the top of the projection optical system 1. It can also be installed at the bottom and airtight. Alternatively, a side suction exhaust seal or the like of the uppermost and lowermost flat plate optical elements of the projection optical system 1 can be adopted as a sealing mechanism, which can be provided at the uppermost and lowermost portions of the projection optical system 1 to be airtight. .

  Next, a second embodiment of the projection optical system of the present invention will be described. However, the outline of the projection optical system according to the second embodiment is almost the same as that of the projection optical system according to the first embodiment described above, and the differences are shown in FIGS. 5A and 5B. Will be described with reference to FIG. FIGS. 5A and 5B show a connecting portion between the lens barrel unit B and the lens barrel unit C of the projection optical system 1. 5 (A) and 5 (B), the same reference numerals are used for the same portions as those in FIGS. 1 (A), 1 (B), FIG. 2, FIG. 3 (A), (B), (C) and FIG. It is attached.

  In the projection optical system 1 of the second embodiment, as shown in FIGS. 5A and 5B, the lens barrel unit is provided on the upper surface and the lower surface (first surface 14a) of the flange portion 14 of the lens barrel unit B. Annular grooves 63 and 64 centering on the optical axis of B are formed. A groove 65 and a groove 66 centering on the optical axis of the lens barrel unit C are also formed on the upper surface (second surface 15a) and the lower surface of the flange portion 15 of the lens barrel unit C.

  The structure other than the grooves 63, 64, 65, 66 is the same as the structure of the lens barrel units B, C of the projection optical system 1 of the first embodiment described above.

  Also in the projection optical system 1 of the second embodiment, the connection between the lens barrel unit B and the lens barrel unit C is performed by sequentially adjusting the position between the lens barrel units B and C and fixing with the bolt 12a nut 16a. Implement by doing. When the position is adjusted, the pressing member 52 is separated from the flange portion 14 while being caught by the lower end portion of the flange portion 15, and does not contact the flange portion 14. Further, the sealing material 54 is also in a space between the outer peripheral surface 15 b of the flange portion 15 and the upper half 52 b of the inner peripheral surface of the pressing member 52, and does not contact the flange portion 14.

  After the position adjustment is completed, both lens barrel units B and C are fixed by the headed bolt 12a and the nut 16a.

  Subsequently, the pressing member 52 is fastened and fixed to the first surface 14a of the flange portion 14 by the headed bolt 13a and the nut 17a for airtightness. As a result, the sealing material 54 is pressed by the pressing member 52 and pressed against the first surface 14a of the flange portion 14 and the outer peripheral surface 15b of the flange portion 15 in the same manner as in the first embodiment described above, and the surface of the sealing material 54 Part 61 of the flange portion 14 is in close contact with the first surface 14 a of the flange portion 14, and another portion 62 is in close contact with the outer peripheral surface 15 b of the flange portion 15.

  At that time, the sealing material 54 pushes the barrel unit C through the flange portion 15 in the center direction. Since the lens barrel unit B and the lens barrel unit C are effectively fixed, the connecting portion does not shift due to this pressing force, and the position adjustment between the lens barrel units B and C does not go wrong. Depending on the rigidity of C, there is a risk of slightly distorting the whole. This distortion may cause the imaging performance of the projection optical system 1 to deteriorate.

  In this regard, in the second embodiment, since the annular grooves 63, 64, 65, 66 are provided on the upper surface and the lower surface of the flange portion 14 and the flange portion 15, this groove structure (exactly 2 The structure of the portion sandwiched between the two grooves) reduces the pressing force and prevents deformation of the lens barrel. Further, if the relaxation of the pressing force by such a groove structure is positively utilized, even if the lens barrel unit B and the lens barrel unit C are thinned to ensure the necessary minimum rigidity, There is also an effect of preventing deformation of the lens barrel. Thereby, the projection optical system 1 can be reduced in weight and the resonance frequency can be increased, and the vibration resistance of the projection optical system 1 can be improved.

  With such a groove structure, a groove 64 formed on the lower surface (first surface 14a) of the flange portion 14 and the upper surface (second surface 15a) of the flange portion 14 are provided between the flange portion 14 and the flange portion 15. Thus, a space surrounded by the groove 66 formed in is formed. Therefore, a hole 68 for connecting the groove space and the outside can be formed in the flange portion 14, and a gas connector 67 can be provided in the hole 68. Then, an exhaust pipe 69 can be connected to the gas connector 67 to exhaust the space between the flange portion 14 and the flange portion 15. As a result, a small amount of water vapor or organic matter generated from the sealing material 54 can be prevented from entering the projection optical system 1, and the gas purity of the optical path space of the projection optical system 1 can be further improved. .

  In the above description, the connection between the lens barrel units B and C has been described. However, for other lens barrel units A, D, and E, annular grooves may be formed on the upper and lower surfaces of the flange. .

  Next, an embodiment of the projection exposure apparatus of the present invention will be described with reference to FIG. The projection optical system 1 according to any one of the above-described embodiments is mounted and fixed to the cast body frame 72 of the exposure apparatus according to the present embodiment via the mounting flange 2 by means of bolts 70 and nuts 71. A gas supply pipe 12 is connected to the gas pipe connector 11 of the projection optical system 1, and nitrogen gas or a rare gas (low absorption gas) or clean air free from organic contaminants is supplied from the gas supply source 84 into the projection optical system 1. Supply. On the other hand, a gas supply pipe 27 is connected to the gas pipe connector 26, and the gas in the projection optical system 1 is exhausted to the gas exhaust mechanism 85.

  Below the body frame 72, a vibration isolation mechanism 96 is provided for preventing transmission of vibration from the floor of the semiconductor factory where the exposure apparatus is installed to the projection optical system 1 and the like. A reticle base 78 is installed on the upper part of the body frame 72, and a reticle stage 77 is provided thereon. A reticle 75 on which a pattern to be exposed is drawn is placed on a reticle stage 77, and the reticle stage 77 can scan the reticle base 78 in the left-right direction in FIG. In addition, a vibration isolation mechanism 82 is also provided between the body frame 72 and the reticle base 78 in order to prevent transmission of vibration accompanying the scanning of the reticle stage 77 to the body frame 72.

The illumination optical system 73 illuminates the reticle 75 with uniform illumination intensity from a light source such as an unillustrated F ₂ (fluorine) laser, ArF (argon fluorine) excimer laser, or KrF (krypton fluorine) excimer laser. .

  A wafer (substrate to be exposed) 87 onto which a pattern is transferred by the exposure apparatus is held by a wafer holder 88, and can be scanned and moved on the wafer base 90 by the wafer stage 89 in the left-right direction in FIG. It can be moved in the direction of the front and back of the paper in FIG. A vibration isolation mechanism 95 is also provided between the wafer base 90 and a floor (not shown) in order to prevent transmission of vibration from the floor of the semiconductor factory to the wafer stage 87.

  The positions of the reticle stage 77 and the wafer stage 89 are measured by the reticle interferometer 79 and the wafer interferometer 92 via the positions of the movable mirrors 76 and 91 provided on the stages, respectively.

  When exposing and transferring the pattern on the reticle 75 onto the wafer 87, the reticle stage 77 and the wafer stage 89 are controlled by a control system (not shown) based on the position measurement values of the reticle interferometer 79 and the wafer interferometer 92. Then, exposure is performed by relative scanning (scanning) while maintaining a predetermined positional relationship between the reticle 75 and the wafer 87.

  When vacuum ultraviolet light having a wavelength of exposure light of 200 nm or less is used, the gas supplied from the gas supply mechanism 84 into the projection optical system 1 is limited to the above-described low absorption gas. Further, when the wavelength is 180 nm or less, the absorption of exposure light by oxygen or water vapor in the air is further enhanced, so that not only the projection optical system 1 but also the optical path in the illumination system 73, the vicinity of the reticle 75, and the projection optical system 1. As for the optical path between the wafer 87 and the wafer 87, it becomes necessary to remove oxygen and water vapor from the optical path and replace the gas with a low absorption gas.

Therefore, when the wavelength of the exposure light is 180 nm or less, for example, when an F ₂ laser with a wavelength of 157 nm is used as the light source, the vicinity of the reticle stage 75 is covered with the reticle hermetic partition 80 and the inside is gasified with a low absorption gas. It needs to be replaced. The gas replacement inside the reticle hermetic partition 80 is performed, for example, by supplying a low-absorbing gas to the inside by a gas supply system (not shown) and exhausting the gas by a gas exhaust system (not shown).

  Between the reticle hermetic partition 80 and the illumination optical system 73 and the projection optical system 1, a flexible film is used in order to prevent the vibration accompanying the movement of the reticle stage 77 from being transmitted to the illumination optical system 73 and the projection optical system 1. The film members 74 and 83 having a bellows shape and a cylindrical shape are connected in an airtight manner. The connecting portion between the film member 83 and the projection optical system 1 is the flange 6 portion of the uppermost barrel unit A or the like.

  Further, it is necessary to cover the vicinity of the wafer stage 87 with the wafer hermetic partition wall 94 and to replace the inside with a low-absorbing gas. The gas replacement inside the wafer hermetic partition wall 94 is performed, for example, by supplying a low-absorbing gas into the interior by a gas supply system (not shown) and exhausting the gas inside by a gas exhaust system (not shown). .

  Between the wafer hermetic partition wall 94 and the projection optical system 1, in order to prevent the vibration accompanying the movement of the wafer stage 87 from being transmitted to the projection optical system 1, the flexible film is a bellows-like and cylindrical film member 86. Are connected more tightly. The connecting portion between the film member 86 and the projection optical system 1 is the flange 32 portion of the lowermost barrel unit E or the like.

In this case, when the low-absorbing gas filled in the projection optical system 1 and the low-absorbing gas filled in the reticle hermetic partition 80 are the same type of gas, the most of the projection optical system 1 described above is used. The upper sealing mechanism may not be provided. Further, when the low-absorbing gas filled in the projection optical system 1 and the low-absorbing gas filled in the wafer hermetic partition wall 94 are the same type of gas, the lowermost sealing mechanism of the projection optical system 1 is used. May not be provided.

  The projection exposure apparatus of the present invention is not limited to the exposure apparatus of the above-described embodiment as long as it is equipped with the projection optical system 1 shown in FIGS.

FIG. 1A is a plan view showing a first embodiment of the projection optical system of the present invention.

FIG. 1B is a front view of the same.
FIG. 2 is an exploded perspective view showing a lens barrel unit C and an airtight mechanism constituting the projection optical system in FIG. 1 with the lower half of the lens barrel unit C omitted. FIG. 3A is a partially enlarged cross-sectional view showing a state before the lens barrel unit B and the lens barrel unit C are connected.

  FIG. 3B is a partially enlarged sectional view showing a state when the lens barrel unit B and the lens barrel unit C are connected.

FIG. 3C is a partially enlarged cross-sectional view showing a state in which the connecting portion between the lens barrel unit B and the lens barrel unit C is airtight.
FIG. 4A is a partially enlarged cross-sectional view further enlarged than FIG. 3C, showing in detail a state in which the connecting portion between the lens barrel unit B and the lens barrel unit C is airtight.

FIG. 4B is a partially enlarged cross-sectional view showing a modification of the embodiment shown in FIG.
FIG. 5 (A) shows a second embodiment of the projection optical system of the present invention, and is a partially enlarged sectional view showing a state before the lens barrel unit B and the lens barrel unit C are connected.

FIG. 5B is a partially enlarged sectional view showing a state when the lens barrel unit B and the lens barrel unit C are connected.
1 is a front view schematically showing a first embodiment of an exposure apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projection optical system A, B, C, D, E Lens barrel unit 3, 10, 18, 19, 28, 35 Lens barrel part 6, 7, 14, 15, 22, 23, 31, 32 Flange part 14a 1st Surface 15a Second surface 4a, 4b, 8a, 8b Mechanical fixing member (fastening member)
12a, 12b, 16a, 16b Mechanical fixing member (fastening member)
20a, 20b, 24a, 24b Mechanical fixing member (fastening member)
29a, 29b, 33a, 33b Mechanical fixing member (fastening member)
5a, 5b, 9a, 9b Mechanical fixing member (fastening member)
13a, 13b, 17a, 17b Mechanical fixing member (fastening member)
21a, 21b, 25a, 25b Mechanical fixing member (fastening member)
30a, 30b, 34a, 34b Mechanical fixing member (fastening member)
52 Pressing member 54 Airtight parts (O-ring)

Claims (22)

In a method for manufacturing a projection optical system that constitutes a projection optical system by connecting a plurality of lens barrel units to each other,
Among the plurality of lens barrel units, the first surface of the first lens barrel unit and the second surface of the second lens barrel unit are opposed to each other,
Adjusting the position between the first barrel unit and the second barrel unit;
After adjusting the position between the first lens barrel unit and the second lens barrel unit, the first lens barrel unit is used to ensure airtightness between the first surface and the second surface. A projection optical system manufacturing method, wherein an airtight member is attached between the first lens barrel unit and the second lens barrel unit. In the manufacturing method of the projection optical system according to claim 1,
The hermetic member may prevent the first lens barrel unit and the second lens barrel unit from affecting the positional relationship between the adjusted first lens barrel unit and the second lens barrel unit. A projection optical system manufacturing method, wherein the projection optical system is attached from the outside. In the manufacturing method of the projection optical system according to claim 1 or 2,
The method of manufacturing a projection optical system, wherein the position adjustment between the lens barrel units is performed by sliding the first lens barrel unit with respect to the second lens barrel unit. In the manufacturing method of the projection optical system according to any one of claims 1 to 3,
The first lens barrel unit has a first flange portion on which the first surface is formed,
The second lens barrel unit includes a second flange portion formed with the second surface and having an outer diameter smaller than the outer diameter of the first flange portion. Method. In the manufacturing method of the projection optical system according to claim 4,
The airtight member is deformable, and an annular airtight component having a size between the outer diameter of the first flange portion and the outer diameter of the second flange portion, and the airtight component, A method for manufacturing a projection optical system, comprising: a pressing member that presses against the first surface of the first lens barrel unit and a side surface of the second flange portion. In the manufacturing method of the projection optical system according to claim 5,
A method of manufacturing a projection optical system, wherein a side surface of the second flange portion has a tapered surface that is inclined so that an outer diameter gradually increases as the distance from the second surface increases. In the manufacturing method of the projection optical system according to claim 6,
Before the first surface of the first lens barrel unit and the second surface of the second lens barrel unit are opposed to each other, the airtight component is disposed on the tapered surface,
After adjusting the position between the first lens barrel unit and the second lens barrel unit, the airtight component is moved between the first surface of the first lens barrel unit and the second flange portion by the pressing member. The projection optical system is manufactured by pressing against the side surface of the projection optical system. In the manufacturing method of the projection optical system according to claim 7,
The projection optical system according to claim 1, wherein the pressing member is pressed after the first flange portion of the first lens barrel unit and the second flange portion of the second lens barrel unit are fastened by a fastening member. Production method. In a projection optical system configured by connecting a plurality of lens barrel units to each other,
Of the plurality of lens barrel units, a first lens barrel unit having a first surface;
A second lens barrel unit having a second surface facing the first surface among the plurality of lens barrel units;
After adjusting the position between the first lens barrel unit and the second lens barrel unit, the first lens barrel unit is used to ensure airtightness between the first surface and the second surface. And an airtight member attached between the second barrel unit and the projection optical system. The projection optical system according to claim 9, wherein
The hermetic member may prevent the first lens barrel unit and the second lens barrel unit from affecting the positional relationship between the adjusted first lens barrel unit and the second lens barrel unit. A projection optical system which is attached from the outside. The projection optical system according to claim 9 or 10,
The projection optical system characterized in that the position adjustment between the lens barrel units is performed by sliding the first lens barrel unit with respect to the second lens barrel unit. The projection optical system according to any one of claims 9 to 12,
The first lens barrel unit has a first flange portion on which the first surface is formed,
The projection optical system according to claim 1, wherein the second lens barrel unit includes a second flange portion formed with an outer diameter smaller than an outer diameter of the first flange portion, the second surface being formed. The projection optical system according to claim 12,
The airtight member is deformable, and an annular airtight component having a size between the outer diameter of the first flange portion and the outer diameter of the second flange portion, and the airtight component, A projection optical system comprising: a pressing member that presses against the first surface of the first barrel unit and a side surface of the second flange portion. The projection optical system according to claim 13, wherein
The projection optical system according to claim 1, wherein the side surface of the second flange portion has a tapered surface that is inclined so that the outer diameter gradually increases as the distance from the second surface increases. The projection optical system according to any one of claims 9 to 14,
The stress generated in the first lens barrel unit and the second lens barrel unit when the airtight member is attached to at least one of the first lens barrel unit and the second lens barrel unit is reduced. A projection optical system comprising a stress reduction mechanism that prevents the positional relationship between the first lens barrel unit and the second lens barrel unit from being affected. The projection optical system according to claim 15, wherein
The projection optical system, wherein the stress reduction mechanism is a groove provided in at least one of the first flange portion and the second flange portion. The projection optical system according to claim 15, wherein
The projection optical system, wherein the stress reduction mechanism is a groove provided on at least one of the first surface and the second surface. The projection optical system according to claim 17,
An exhaust connector is connected to a space formed by the groove provided on the first surface and the groove provided on the second surface, and the gas flowing into the space via the exhaust connector is connected to the exhaust connector. A projection optical system characterized by exhausting. In a projection exposure apparatus that exposes and transfers a predetermined pattern onto a substrate to be exposed via a projection optical system,
A projection exposure apparatus comprising the projection optical system according to claim 9 as the projection optical system. The projection exposure apparatus according to claim 19,
An exposure apparatus for exposing and transferring the exposure light having a wavelength of 200 nm or less. A projection exposure apparatus according to claim 19 or 20,
A projection exposure apparatus characterized in that the inside of the projection optical system is replaced with a gas that hardly absorbs exposure light for exposure transfer or has a low absorptivity of the exposure light. A projection exposure apparatus according to claim 21,
A projection exposure apparatus, wherein the gas is nitrogen gas or a rare gas.

Images