Abstract:
An exposure apparatus has an optical system and transfers a pattern of a mask to a substrate via the optical system. The apparatus includes a structure, a partition wall which defines a space including an optical path of the optical system, and an elastic seal member which couples the structure and the partition wall to seal the space. The elastic seal member is arranged so that a hollow cylinder is compressed in a direction of an axis of the hollow cylinder. The hollow cylinder, in an uncompressed state, includes a member undulated in a cross section perpendicular to the axis and a shape of the uncompressed-state hollow cylinder in the cross section being substantially uniform along the axis.

Description:
FIELD OF THE INVENTION 
   The present invention relates to an exposure apparatus which transfers a pattern onto a substrate using an exposure beam. 
   BACKGROUND OF THE INVENTION 
   A manufacturing process for a semiconductor element such as an LSI or VLSI formed from a micropattern uses a reduction type projection exposure apparatus for transferring by reduction projection a circuit pattern drawn on a mask onto a substrate coated with a photosensitive agent. With an increase in the packaging density of semiconductor elements, demands have arisen for further micropatterning. Exposure apparatuses are coping with micropatterning along with the development of a resist process. 
   A means for increasing the resolving power of the exposure apparatus includes a method of changing the exposure wavelength to a shorter one, and a method of increasing the numerical aperture (NA) of the projection optical system. 
   As for the exposure wavelength, the 365-nm i-line has been replaced by a KrF excimer laser with an oscillation wavelength of around 248 nm. Also, an ArF excimer laser with an oscillation wavelength around 193 nm and a fluorine (F 2 ) excimer laser with an oscillation wavelength around 157 nm have been developed. 
   An ArF excimer laser with a wavelength around far ultraviolet rays, particularly, 193 nm, and a fluorine (F 2 ) excimer laser with an oscillation wavelength around 157 nm are known to have a plurality of oxygen (O 2 ) absorption bands around their wavelength bands. 
   For example, a fluorine excimer laser has been applied to an exposure apparatus because of a short wavelength of 157 nm. The 157-nm wavelength falls within a wavelength region generally called a vacuum ultraviolet region. In this wavelength region, light is greatly absorbed by oxygen molecules, and hardly passes through air. Thus, the fluorine excimer laser can only be applied in an environment in which the atmospheric pressure is decreased to almost vacuum and the oxygen concentration is fully decreased. 
   According to a reference “Photochemistry of Small Molecules” (Hideo Okabe, A Wiley-Interscience Publication, 1978, p. 178), the absorption coefficient of oxygen to 157-nm light is about 190 atm −1 cm −1 . This means that, when 157-nm light passes through gas at an oxygen concentration of 1% at one atmospheric pressure, the transmittance per cm is only
 
 T =exp(−190×1 cm×0.01 atm)=0.150
 
   Oxygen absorbs light to generate ozone (O 3 ), and ozone promotes absorption of light, greatly decreasing the transmittance. In addition, various products generated by ozone are deposited on the surface of an optical element, decreasing the efficiency of the optical system. 
   To prevent this, the oxygen concentration in the optical path is suppressed to a low level of several ppm order, or less, by a purge mechanism using inert gas, such as nitrogen in the optical path of the exposure optical system of a projection exposure apparatus using a far ultraviolet laser, such as an ArF excimer laser or a fluorine (F 2 ) excimer laser, as a light source. 
   In such an exposure apparatus using an ArF excimer laser beam with a wavelength around far ultraviolet rays, particularly, 193 nm, or a fluorine (F 2 ) excimer laser beam with a wavelength around 157 nm, an ArF excimer laser beam or fluorine (F 2 ) excimer laser beam is readily absorbed by a substance. The optical path must be purged to several ppm order or less. This also applies to moisture, which must be removed to the ppm order or less. 
   To ensure the transmittance or stability of ultraviolet rays, the ultraviolet path of the reticle stage or the like of an exposure apparatus or the like is purged with inert gas. For example, Japanese Patent Laid-Open No. 6-260385 discloses a method of spraying inert gas toward a photosensitive substrate. However, oxygen and moisture cannot be satisfactorily purged. Japanese Patent Laid-Open No. 8-279458 discloses a method of covering the whole space near a photosensitive substrate with a sealing member from the lower end of a projection optical system. However, this method is not practical because it is difficult to move the stage. 
   As described above, an exposure apparatus using ultraviolet rays, particularly, an ArF excimer laser beam or fluorine (F 2 ) excimer laser beam suffers from large absorption by oxygen and moisture at the wavelength of the ArF excimer laser beam or fluorine (F 2 ) excimer laser beam. To obtain a sufficient transmittance and stability of ultraviolet rays, the oxygen and moisture concentrations must be reduced. 
   From this, it is desired to develop an effective means for purging the ultraviolet path in an exposure apparatus, particularly, the vicinities of a wafer and reticle with inert gas. 
   However, vibration sources such as the motors and air compressors of various units installed on the floor and units to be isolated from vibrations, such as a projection optical system, an alignment system, a laser interferometer, and a stage, supported by a vibration isolating mechanism, coexist in an exposure apparatus. For this reason, if a space between the vibration sources and the units is purged with inert gas, vibrations are transmitted through a connecting member arranged between them to sustain airtightness. Consequently, the units supported by the vibrations isolating mechanism vibrate, thereby causing a reduction in exposure precision, and the like. 
   Assume that a bellows structural member is employed as the connecting member to sustain airtightness. In this case, the bellows structure member has flexibility in the compression direction and high rigidity in the shear and twist directions, but vibrations cannot be satisfactorily isolated. 
   SUMMARY OF THE INVENTION 
   The present invention has been made in consideration of the above-mentioned background, and has as its object to, e.g., suppress transmission of vibration between two independently supported structures through a member for connecting the structures and forming an enclosed space. 
   According to the present invention, there is provided an exposure apparatus which transfers a pattern onto a substrate with exposure light, characterized by comprising a partition wall which encloses a path of exposure light and isolates the path from surroundings, and a connecting member in a tubular form which connects the partition wall and a structure supported independently of the partition wall and sustains airtightness in a space enclosed with the partition wall, wherein a section of the connecting member, taken in a direction perpendicular to an axis of the connecting member, has a three-dimensional portion. Use of a connecting member with this structure suppresses transmission of vibrations between a room (closed space) comprising a partition wall and a structure supported independently of the partition wall, thereby avoiding disadvantages caused by transmission of vibrations, e.g., any decrease in exposure precision. 
   According to a preferred embodiment of the present invention, the section of the connecting member preferably has a plurality of three-dimensional portions. 
   According to a preferred embodiment of the present invention, the connecting member preferably connects the structure and the partition wall in an axially compressed state. 
   According to a preferred embodiment of the present invention, the connecting member is preferably made of resin, rubber (e.g., fluororubber), or the like. 
   According to a preferred embodiment of the present invention, the connecting member is preferably made of a material having a thickness of not more than two mm. Alternatively, the connecting member is preferably arranged to be resistant to a gage pressure of not more than one MPa. 
   In the present invention, the term “tubular form” includes a structure which has a polygonal (e.g., quadrangular) section with a three-dimensional portion and a structure which has a circular section with a three-dimensional portion. 
   According to a preferred embodiment of the present invention, preferably, the structure is supported by a vibration isolating mechanism, and the partition wall is preferably supported by a structure which can transmit vibrations to the partition wall. The partition wall can be supported by a support member which receives vibrations from a floor. The partition wall may connect to a second structure other than the structure through a second connecting member, and in this case, the second connecting member preferably has the same structure as a structure of the connecting member. 
   Alternatively, the structure is supported by a structure which can transmit vibrations to the structure, and the partition wall may be supported through a vibration isolating mechanism. 
   According to a preferred embodiment of the present invention, a substrate stage or reticle stage can be arranged in the space enclosed with the partition wall. 
   According to the present invention, there is provided a device manufacturing method comprising a step of transferring a pattern onto a substrate using the above-mentioned exposure apparatus, and a step of developing the substrate. 
   Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
       FIG. 1  is a perspective view showing the structure of an airtightness sustaining mechanism according to a preferred embodiment of the present invention; 
       FIG. 2  is a view of a model of an airtightness sustaining mechanism shown in  FIG. 1 ; 
       FIG. 3  is a graph showing the flexibility of the model shown in  FIG. 2 , which depends on the shape of a three-dimensional portion; 
       FIG. 4  is a view showing the schematic arrangement of an exposure apparatus according to the preferred embodiment of the present invention; 
       FIG. 5  is a perspective view of a partition wall (purge chamber) portion in  FIG. 4 ; 
       FIG. 6  is a sectional view of a connecting member of the airtightness sustaining mechanism, taken in a direction perpendicular to the axial direction; 
       FIG. 7  is a view showing another structure of the connecting member; 
       FIG. 8  is a view showing still another structure of the connecting member; 
       FIG. 9  is a view showing still another structure of the connecting member; 
       FIG. 10  is a view of a model of an airtightness sustaining mechanism with a bellows structure; 
       FIG. 11  is a view of a model of an airtightness sustaining mechanism according to the present invention; 
       FIG. 12  is a view showing the flexibility of the airtightness sustaining mechanism with the bellows structure; 
       FIG. 13  is a view showing the flexibility of the airtightness sustaining mechanism according to the present invention; 
       FIG. 14  is a flow chart showing the flow of the whole manufacturing process of a semiconductor device using the exposure apparatus of the present invention; 
       FIG. 15  is a flow chart showing the detailed flow of the wafer process using the exposure apparatus of the present invention; 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   First, the principle of the present invention will be described. 
     FIG. 10  is a view of a model of a conventional airtightness sustaining mechanism with a bellows structure. The modeled structure has a hollow connecting member  130  between a first portion (flange)  110  and a second portion (flange)  120 . A distance between the first portion  110  and the second portion  120  in an uncompressed state is represented by T 1 . If the structure is vertically compressed such that the distance T 1  reduces to a distance T 2 , the connecting member  130  transforms into a bellows structure portion  130 ′. 
     FIG. 11  is a view of a model of an airtightness sustaining mechanism according to the present invention. The modeled structure has a tubular or hollow connecting member  230  between a first portion (flange)  210  and a second portion (flange)  220 . In this structure, the connecting member  230  has a three-dimensional portion  231  comprised of axially (in the Z direction in  FIG. 11 ) extending projections and recesses. Use of the structure so compressed as to reduce a thickness T 1  of the connecting member can provide an airtightness sustaining mechanism with high flexibility in the shear direction (X direction in FIG.  11 ). 
   It will be described with reference to  FIGS. 12 and 13  that the airtightness sustaining mechanism of the present invention is better in flexibility in the shear direction than the conventional airtightness sustaining mechanism. 
     FIG. 12  shows the first portion (flange)  110  and second portion (flange)  120  of the conventional airtightness sustaining mechanism with the bellows structure. Assume that a length L 2 , in the diagonal direction, of a surface  131  of a connecting member (not shown) interposed between the first portion  110  and the second portion  120  does not change. If a distance between the first portion  110  and the second portion  120  reduces from T 1  to T 2 , the first portion  110  and the second portion  120  have a relative shift S 2  in the shear direction (X direction in FIG.  13 ). 
     FIG. 13  shows the first portion (flange)  210  and second portion (flange)  220  of the airtightness sustaining mechanism of the present invention. Assume that a length L 1 , in the diagonal direction, of the surface  231  of a connecting member (not shown) interposed between the first portion  210  and the second portion  220  does not change. If a distance between the first portion  210  and the second portion  220  reduces from T 1  to T 2 , the first portion  210  and the second portion  220  have a relative shift S 1  in the shear direction (X direction in FIG.  13 ). 
   As can be seen from  FIGS. 12 and 13 , the shift amount S 1 , in the shear direction, of the airtightness sustaining mechanism of the present invention is larger than the shift amount S 2 , in the shear direction, of the conventional airtightness sustaining mechanism. That is, the airtightness sustaining mechanism of the present invention is more flexible than the conventional airtightness sustaining mechanism and can increase a shift amount between the first member and the second member. 
   The airtightness sustaining mechanism of the present invention can be applied to various apparatuses including an exposure apparatus. The airtightness sustaining mechanism of the present invention is particularly suitable for an exposure apparatus using far ultraviolet rays such as an ArF excimer laser with a wavelength around 193 nm and a fluorine (F 2 ) excimer laser with a wavelength around 157 nm. 
   An airtightness sustaining mechanism according to a preferred embodiment of the present invention will be described next.  FIG. 1  is a perspective view showing the structure of the airtightness sustaining mechanism according to the preferred embodiment of the present invention. The airtightness sustaining mechanism is suitable for an exposure apparatus for manufacturing devices such as a semiconductor device. 
   An airtightness sustaining mechanism  50  according to the preferred embodiment of the present invention causes the first structure and the second structure to communicate with each other and isolates them from the external space (i.e., sustains airtightness), thereby forming an enclosed space. At least one of the first and second structures comprises a structure which forms a space. 
   The airtightness sustaining mechanism  50  comprises a first flange  38   a  to be connected to the first structure, a second flange  38   b  to be connected to the second structure, and a tubular or hollow connecting member  37 , which connects the first flange  38   a  and second flange  38   b . A “tubular” structure may be any structure with a closed-figure section, such as a polygonal section, as well as a circular section. 
   The airtightness sustaining mechanism  50  is typically interposed between the first structure and the second structure in an axially compressed state. 
   The connecting member  37  has one or more three-dimensional portions  37   a  in a section taken in a direction (along a plane parallel to the X-Y plane in  FIG. 1 ) perpendicular to the axial direction (Z direction in FIG.  1 ), i.e., a direction in which the first and second flanges  38   a  and  38   b  face each other, as shown in FIG.  6 . The three-dimensional portion  37   a  comprises a projection and a recess which axially extend. The three-dimensional portion  37   a  is preferably provided on each side of the connecting member  37 . More preferably, each side of the connecting member has a plurality of three-dimensional portions  37   a.    
   By providing one or more three-dimensional portions  37   a  in the connecting member  37 , the airtightness sustaining mechanism  50  can increase the flexibility in the shear (X and Y directions in FIG.  1 ), compression (Z direction in FIG.  1 ), and rotation (directions about the X-, Y- and Z-axes, particularly, the direction about the Z-axis) directions. With this structure, even if the connecting member  37  is made of a material with small elasticity, such as a rubber sheet combined with a fabric, the airtightness sustaining mechanism  50  can obtain high flexibility in all of the compression, shear, and rotation directions. 
   The connecting member  37  is preferably made of resin, rubber (e.g., fluororubber), or the like. A wall member constituting the connecting member  37  preferably has a thickness of two mm or less. The connecting member  37  is preferably arranged to be resistant to a gage pressure of one MPa or less. The above-mentioned arrangement contributes to an increase in flexibility of the connecting member  37 . 
   As an example, the flexibility in the shear direction will be described below. For the sake of descriptive simplicity,  FIG. 2  shows a model of the airtightness sustaining mechanism shown in  FIG. 1. A  first member (flange)  41 , a second member (flange)  42 , and a connecting member  43  in  FIG. 2  correspond to the first flange  38   a , second flange  38   b , and connecting member  37  in  FIG. 1 , respectively. The model of  FIG. 2  has a three-dimensional portion including a projection  43   a  on a side of the connecting member  37 . Although  FIG. 2  shows only one projection  43   a , a plurality of projections  43   a  may be provided at intervals A. 
   A maximum shift amount dA which indicates the flexibility, in the shear direction, of the airtightness sustaining mechanism shown in  FIG. 2  can be represented by equation (1):
 
 dA =( A   2 +2 dH·H−dH   2 ) 1/2   −A   (1)
 
where A is a distance between the projections  43   a  of the connecting member  43  (distance between steps), H is a length, in the axial direction (Z direction), of the connecting member  43 , and dH is a compression amount in the axial direction.
 
     FIG. 3  shows the maximum shift amount dA when the length H=60 mm and the compression amount dH=50 mm are substituted into equation (1). The maximum shift amount dA depends on the distance A. 
   As shown in  FIG. 3 , by increasing the number of three-dimensional portions and decreasing the distance A between the projections  43   a , the maximum shift amount can be increased, thereby obtaining a structure with high flexibility. 
     FIG. 4  is a schematic view showing an example of an exposure apparatus having the airtightness sustaining mechanism shown in FIG.  1 . The exposure apparatus main body is stored in a chamber  1 , and the ambient temperature of the exposure apparatus main body is so controlled as to have a precision of, e.g., about ±0.03° C. 
   The exposure apparatus shown in  FIG. 4  comprises a base frame  2  serving as the base of the exposure apparatus main body, a reticle stage  3  which can move while holding a reticle (master), a wafer stage  4  which can move while holding a wafer (substrate), an illumination optical system  5  which illuminates a reticle with illumination light, a projection optical system  6  which reduces and projects a reticle pattern onto a wafer at a predetermined magnification (e.g., 4:1), a lens barrel surface plate  7  which holds the projection optical system  6 , and an air-conditioned equipment room  8  which supplies temperature-controlled clean air. 
   The projection optical system  6  is a single barrel type catadioptric system, similar to a projection optical system disclosed in Japanese Patent Laid-Open No. 2001-27727. The projection optical system  6  has a closed structure, and its interior is purged with temperature/humidity-controlled inert gas such as nitrogen or helium. 
   The illumination optical system  5  introduces illumination light through a beam line extending from a light source device  46  which is set on the floor separately from the exposure apparatus or an internal light source device. The illumination optical system  5  generates slit light from the introduced illumination light through various lenses and stops, and slit-illuminates a reticle held by the reticle stage  3  from above the reticle. Examples of illumination light are an excimer laser beam (e.g., KrF, ArF, or F 2 ), harmonic (e.g., YAG laser beam or metal vapor laser beam), and ultraviolet rays (e.g., i-line). The illumination optical system  5  has a closed or almost closed structure, and its interior is purged with temperature/humidity-controlled inert gas such as nitrogen or helium. 
   The base frame  2  is set on the installation floor of the clean room of a semiconductor manufacturing factory. The base frame  2  is fixed to the floor at high rigidity, and can be regarded to be substantially integrated with the floor or extend from the floor. The base frame  2  includes three or four high-rigidity columns, and vertically supports the lens barrel surface plate  7  through active dampers (vibration isolating mechanisms)  9  at the tops of the columns. The active damper  9  incorporates an air spring, a damper, and an actuator. The active damper  9  prevents transmission of high-frequency vibrations from the floor to the lens barrel surface plate  7 , and actively compensates for the tilt or swing of the lens barrel surface plate  7 . 
   The lens barrel surface plate  7  which holds the projection optical system  6  also supports a reticle stage surface plate  10  through a reticle holding frame  34 . The lens barrel surface plate  7  is equipped with an alignment detector for detecting the alignment states of a reticle and wafer. Alignment is performed using the lens barrel surface plate  7  as a reference. 
   A wafer is set on the wafer stage  4 . The position of the wafer stage  4  is measured by an interferometer (not shown), and the wafer stage  4  can be driven in an optical axis direction (Z direction) of the projection optical system  6 , X and Y directions perpendicular to the optical axis direction, and ωx, ωy, and ωz directions around the axes. 
   A linear motor is adopted as an alignment driving source. The wafer stage  4  basically comprises a two-dimensional stage constituted by an X stage which moves straight in the X direction, an X linear motor, a Y stage which moves straight in the Y direction perpendicular to the X direction, and a Y linear motor. A stage capable of moving in the Z direction, tilt (ωX and ωY) directions, and rotational (ωZ) direction is mounted on the two-dimensional stage. 
   The wafer stage  4  is supported by a wafer stage surface plate  11 , and moves on the X-Y horizontal guide surface (guide surface) of the wafer stage surface plate  11 . The wafer stage surface plate  11  is supported on a stage base member  12  by three (or four) support legs. 
   The stage base member  12  is vertically supported by the base frame  2  at three portions through three active dampers (vibration isolating mechanisms)  13 . Most of the load of the stage base member  12  and members mounted on it is basically supported by the three active dampers  13 . The load received by the active dampers  13  is received by the base frame  2  which is substantially integrated with the floor. Thus, the basic load of the wafer stage  4  is substantially supported by the floor. The active damper  13  uses an air spring capable of supporting a large load. 
   The position of the reticle stage  3  is also measured by an interferometer (not shown), and the reticle stage  3  can be driven in the X and Y directions perpendicular to the optical axis direction (Z direction) of the projection optical system  6 . 
   By illumination of the illumination system  5 , the pattern image of a reticle is projected onto a wafer held by the wafer stage  4  through the projection optical system  6 . At this time, the wafer stage  4  and reticle stage  3  are relatively moved in a direction perpendicular to the optical axis direction (Z direction) of the projection optical system  6 . As a result, the pattern image is transferred in a predetermined region on the wafer. The same transfer operation is repeated by step &amp; scan for a plurality of exposure regions on the wafer, thereby transferring the pattern on the entire surface of the wafer. 
   The reticle is stored in a reticle storage  15  and transferred by a reticle transfer system  16 . The reticle storage  15  and reticle transfer system  16  are arranged in a space  17  within the chamber  1 . The reticle is transferred by the reticle transfer system  16  to a reticle alignment unit  35 . The reticle alignment unit  35  is fixed to the upper surface of the reticle holding frame  34 , mounts/recovers the reticle on/from the reticle stage  3 , and aligns the position of the reticle. 
   The wafer is stored in a wafer storage  20  and transferred by a wafer transfer system  21 . The wafer storage  20  and wafer transfer system  21  are arranged in a space  18  within the chamber  1 . The wafer is mounted/recovered on/from the wafer stage  4  by the wafer transfer system  21 . 
   An airtightness sustaining mechanism mounted near the wafer stage  4  of the exposure apparatus will be described next. As shown in  FIG. 4 , a box-like partition wall (purge chamber)  23  is interposed between the lens barrel surface plate  7  and the wafer stage  4 .  FIG. 5  is a perspective view of the partition wall  23  and its surroundings in FIG.  4 . The partition wall  23  is supported through a support member  24  by the base frame  2 . The partition wall  23  has openings in the upper and lower surfaces. The upper opening and the facing lower surface of the lens barrel surface plate (an example of a structure)  7  are connected by an airtightness sustaining mechanism  25  so as to sustain airtightness. 
   The lower opening of the partition wall  23  and the facing upper surface of the stage base member (an example of a structure)  12  which supports the wafer stage  4  are also connected by an airtightness sustaining mechanism  26  so as to sustain airtightness. 
   Each of the airtightness sustaining mechanisms  25  and  26  has a structure shown in FIG.  1  and is very flexible. The airtightness sustaining mechanisms  25  and  26  can thus keep the interior of the partition wall  23  airtight without transmitting vibrations of the box-like partition wall  23  which swings by vibrations from the exposure apparatus installation floor, to the lens barrel surface plate  7  and wafer stage  4  which are supported by the active dampers  9  and active dampers  13 . 
   The box-like partition wall  23  also has an opening on a side on which the wafer transfer system  21  is arranged. This opening and an opening formed in a chamber (an example of the second structure)  22 , which covers the wafer transfer system  21 , are also connected by an airtightness sustaining mechanism  27   a  having the structure shown in  FIG. 1  so as to sustain airtightness. 
   The box-like partition wall  23  also has an opening on a side of a filter  29  connected to the air-conditioned equipment room  8  through an air duct. This opening and the filter (an example of the second structure)  29  are also connected by an airtightness sustaining mechanism  27   b  having the structure shown in  FIG. 1  so as to sustain airtightness. 
   Temperature-controlled inert gas such as nitrogen is supplied to a space (purge space) enclosed with the partition wall  23  near the wafer stage  4  through the filter  29 . Gas supplied to the purge space passes through the space  18  and returns to the air-conditioned equipment room  8  again through a return portion  30 . More specifically, a circulation system of inert gas through the active damper  9 , purge space, space  18 , and return portion  30  is constituted. 
   An airtightness sustaining mechanism mounted near the reticle stage  3  will be described next. As shown in  FIG. 4 , a box-like partition wall (purge chamber)  32  is arranged to cover the reticle stage  3 . The partition wall  32  is supported by the reticle holding frame  34 . 
   The box-like partition wall  32  has an opening on a side on which the reticle transfer system  16  as well as the optical path is arranged. This opening and an opening formed in a chamber  36  which airtightly covers the reticle transfer system  16  are also connected by an airtightness sustaining mechanism  28   a  having the structure shown in  FIG. 1  so as to sustain airtightness. 
   The box-like partition wall  32  also has an opening on a side of a filter  33  connected to the air-conditioned equipment room  8  through an air duct. This opening and the filter  33  are also connected by an airtightness sustaining mechanism  28   b  having the structure shown in  FIG. 1  so as to sustain airtightness. 
   Each of the airtightness sustaining mechanisms  28   a  and  28   b  has a structure shown in FIG.  1  and is very flexible. The airtightness sustaining mechanisms  28   a  and  28   b  can thus keep the interior of the partition wall  32  airtight without transmitting vibrations of the chamber  36  of the reticle transfer system  16  which swings by vibrations from the exposure apparatus installation floor and vibrations of the air-conditioned equipment room  8 , to the lens barrel surface plate  7  and reticle stage  3  which are supported by the active dampers  9 . 
   Temperature-controlled inert gas such as nitrogen is supplied to a space (purge space) enclosed with the partition wall  32  near the reticle stage  3  through the filter  33 . 
   With this arrangement, the optical path that extends from the illumination optical system  5  to the projection optical system  6  through a reticle and the optical path that extends from the projection optical system  6  to a wafer are purged with inert gas such as nitrogen having high transmittance even for far ultraviolet rays such as an ArF excimer laser beam or fluorine (F 2 ) excimer laser beam. Since illumination light reaches the wafer surface at high transmittance, the exposure time can be shortened to increase the throughput of the exposure process. 
   The lens barrel surface plate  7  and wafer stage  4  which are supported by the active dampers  9  and active dampers  13 , respectively, are connected to the purge chamber constituted by the partition wall  23  through the flexible airtightness sustaining mechanisms  25  and  26 , and transmission of vibrations from the purge chamber is suppressed. In addition, the purge chamber is connected to the chamber  22  of the wafer transfer system  21  and air-conditioned equipment room  8  through the flexible airtightness sustaining mechanisms  27   a  and  27   b , and transmission of vibrations from the chamber  22  and air-conditioned equipment room  8  to the purge chamber is suppressed. 
   The lens barrel surface plate  7  and reticle stage  3 , which are supported by the active dampers  9 , are connected to the chamber  36  of the reticle transfer system  16  and air-conditioned equipment room  8  through the flexible airtightness sustaining mechanisms  28   a  and  28   b , and transmission of vibrations from the chamber  36  and air-conditions equipment room  8  to the purge chamber is suppressed. 
   A sectional shape of the connecting member  37  shown in  FIG. 1  can be changed to, eg., any one of the shapes shown in  FIGS. 7  to  9 . Each of  FIGS. 7 and 8 , and  FIG. 6  described above, shows an example in which a section taken in a direction perpendicular to the axial direction has a certain polygonal shape with a three-dimensional portion, and the three-dimensional portions in  FIGS. 6  to  8  have different shapes.  FIG. 9  shows an example in which a section taken in a direction perpendicular to the axial direction has a circular shape with a three-dimensional portion. 
   A semiconductor device manufacturing process using the above-described exposure apparatus will be explained.  FIG. 14  is a flow chart showing the flow of the whole manufacturing process of a semiconductor. In step  1  (circuit design), the circuit of a semiconductor device is designed. In step  2  (mask formation), a mask is formed on the basis of the designed circuit pattern. In step  3  (wafer formation), a wafer is formed using a material such as silicon. In step  4  (wafer process), called a pre-process, an actual circuit is formed on the wafer by lithography using the mask and wafer device using the exposure apparatus of the present invention. Step  5  (assembly), called a post-process, is the step of forming a semiconductor chip by using the wafer formed in step  4 , and includes an assembly process (dicing and bonding) and packaging process (chip encapsulation). In step  6  (inspection), the semiconductor device manufactured in step  5  undergoes inspections such as an operation confirmation test and a durability test. After these steps, the semiconductor device is completed and shipped in step  7 . 
     FIG. 15  is a flow chart showing the detailed flow of the wafer process using the exposure apparatus of the present invention. In step  11  (oxidation), the wafer surface is oxidized. In step  12  (CVD), an insulating film is formed on the wafer surface. In step  13  (electrode formation), an electrode is formed on the wafer by vapor deposition. In step  14  (ion implantation), ions are implanted in the wafer. In step  15  (resist processing), a photosensitive agent is applied to the wafer. In step  16  (exposure), the above-mentioned exposure apparatus transfers a circuit pattern onto the wafer. In step  17  (developing), the exposed wafer is developed. In step  18  (etching), the resist is etched except for the developed resist image. In step  19  (resist removal), an unnecessary resist after etching is removed. These steps are repeated to form multiple circuit patterns on the wafer. 
   According to the present invention, for example, vibration transmission between two independently supported structures through a member for connecting the structures and forming an enclosed space can be suppressed. This can increase the exposure precision in an exposure apparatus. 
   As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.