Abstract:
An exposure apparatus exposes a substrate with light from an object through an optical assembly and liquid. The exposure apparatus includes a stage and a liquid supply system. The stage is movable relative to the optical assembly and holds the substrate so that the substrate faces the optical assembly across the liquid. The liquid supply system includes an outlet arranged so as to face a top surface of the substrate held by the stage and supplies the liquid from the outlet onto the top surface. The stage includes a support which supports an undersurface of the substrate, and a channel having a port. The port is arranged outside the support so as to recover the liquid supplied from the outlet and flowing outwardly from the top surface of the substrate supported by the support.

Description:
RELATED APPLICATIONS 
       [0001]    This is a Division of U.S. patent application Ser. No. 13/543,238 filed Jul. 6, 2012, which in turn is a Division of U.S. patent application Ser. No. 12/155,377 filed Jun. 3, 2008 (now U.S. Pat. No. 8,243,253), which is a Division of U.S. patent application Ser. No. 11/235,323 filed Sep. 27, 2005 (now U.S. Pat. No. 7,397,532), which is a Continuation of International Application No. PCT/US2004/009993 filed Apr. 1, 2004, which claims the benefit of U.S. Provisional Patent Application No. 60/462,114 filed Apr. 10, 2003. The disclosures of these applications are incorporated herein by reference in their entireties. 
     
    
     BACKGROUND 
       [0002]    Exposure apparatus are commonly used to transfer images from a reticle onto a semiconductor wafer during semiconductor processing. A typical exposure apparatus includes an illumination source, a reticle stage assembly that positions a reticle, an optical assembly, a wafer stage assembly that positions a semiconductor wafer, and a measurement system that precisely monitors the position of the reticle and the wafer. 
         [0003]    Immersion lithography systems utilize a layer of immersion fluid that fills a gap between the optical assembly and the wafer. The wafer is moved rapidly in a typical lithography system and it would be expected to carry the immersion fluid away from the gap. This immersion fluid that escapes from the gap can interfere with the operation of other components of the lithography system. For example, the immersion fluid can interfere with the measurement system that monitors the position of the wafer. 
       SUMMARY 
       [0004]    The invention is directed to an exposure apparatus for transferring an image to a device. In one embodiment, the exposure apparatus includes a support, an optical assembly, an immersion fluid source and a device stage assembly. A gap separates the optical assembly from the device. The immersion fluid source delivers an immersion fluid to the gap. The support supports the device. In one embodiment, the device stage assembly includes a sloped region positioned near the device. The sloped region facilitates the flow of the immersion fluid that exits the gap away from the device. 
         [0005]    In one embodiment, the sloped region includes one or more coatings and/or one or more features that facilitate movement of the immersion fluid down the sloped region. For example, a hydrophobic type coating and/or a hydrophilic type coating can be utilized. 
         [0006]    In one embodiment, the device stage assembly includes a collection region that receives immersion fluid from the sloped region and a recovery device that removes immersion fluid from the collection region. 
         [0007]    In one embodiment, the sloped region includes a first subregion having a first characteristic and a second subregion having a second characteristic that is different than the first characteristic. As an example, the first characteristic can include a first coating and the second characteristic can include a second coating that is different than the first coating. 
         [0008]    In another embodiment, the first subregion is at a first angle relative to a top of the device, the second subregion is at a second angle relative to the top of the device, and the first angle is different than the second angle. In this embodiment, the device table assembly can include a first collection region that is in fluid communication with the first subregion, a second collection region that is in fluid communication with the second subregion, and a recovery device that removes immersion fluid from the collection regions. 
         [0009]    The invention also is directed to an exposure apparatus, a wafer, a device, a method for controlling an environment in a gap, a method for making an exposure apparatus, a method for making a device, and a method for manufacturing a wafer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The invention will be described in conjunction with the following drawings of exemplary embodiments in which like reference numerals designate like elements, and in which: 
           [0011]      FIG. 1  is a side illustration of an exposure apparatus having features of the invention; 
           [0012]      FIG. 2A  is a cut-away view taken on line  2 A- 2 A of  FIG. 1 ; 
           [0013]      FIG. 2B  is a cut-away view taken on line  2 B- 2 B of  FIG. 2A , and FIG.  2 B′ is a similar cut-away view of a modified embodiment; 
           [0014]      FIG. 2C  is a top plan view of a device stage and device from  FIG. 2A ; 
           [0015]      FIG. 3A  is a top plan view of a device and another embodiment of a device stage having features of the invention; 
           [0016]      FIG. 3B  is a cut-away view taken on line  3 B- 3 B of  FIG. 3A ; 
           [0017]      FIG. 4  is a top plan view of a device and another embodiment of a device stage having features of the invention; 
           [0018]      FIG. 5A  is an enlarged side cut-away view of a portion of a device and another embodiment of a device stage; 
           [0019]      FIG. 5B  is a top plan view of a portion of the device stage of  FIG. 5A ; 
           [0020]      FIG. 6A  is a flow chart that outlines a process for manufacturing a device in accordance with the invention; and 
           [0021]      FIG. 6B  is a flow chart that outlines device processing in more detail. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0022]      FIG. 1  is a schematic illustration of a precision assembly, namely an exposure apparatus  10  having features of the invention. The exposure apparatus  10  includes an apparatus frame  12 , an illumination system  14  (irradiation apparatus), an optical assembly  16 , a reticle stage assembly  18 , a device stage assembly  20 , a measurement system  22 , a control system  24 , and a fluid environmental system  26 . The design of the components of the exposure apparatus  10  can be varied to suit the design requirements of the exposure apparatus  10 . 
         [0023]    A number of Figures include an orientation system that illustrates an X axis, a Y axis that is orthogonal to the X axis, and a Z axis that is orthogonal to the X and Y axes. It should be noted that these axes also can be referred to as the first, second and third axes. 
         [0024]    The exposure apparatus  10  is particularly useful as a lithographic device that transfers a pattern (not shown) of an integrated circuit from a reticle  28  onto a semiconductor wafer  30  (illustrated in phantom). The wafer  30  also is referred to generally as a device, or work piece. The exposure apparatus  10  mounts to a mounting base  32 , e.g., the ground, a base, or floor or some other supporting structure. 
         [0025]    There are a number of different types of lithographic devices. For example, the exposure apparatus  10  can be used as a scanning type photolithography system that exposes the pattern from the reticle  28  onto the wafer  30 , with the reticle  28  and the wafer  30  moving synchronously. In a scanning type lithographic apparatus, the reticle  28  is moved perpendicularly to an optical axis of the optical assembly  16  by the reticle stage assembly  18 , and the wafer  30  is moved perpendicularly to the optical axis of the optical assembly  16  by the wafer stage assembly  20 . Irradiation of the reticle  28  and exposure of the wafer  30  occur while the reticle  28  and the wafer  30  are moving synchronously. 
         [0026]    Alternatively, the exposure apparatus  10  can be a step-and-repeat type photolithography system that exposes the reticle  28  while the reticle  28  and the wafer  30  are stationary. In the step and repeat process, the wafer  30  is in a constant position relative to the reticle  28  and the optical assembly  16  during the exposure of an individual field. Subsequently, between consecutive exposure steps, the wafer  30  is consecutively moved with the device stage assembly  20  perpendicularly to the optical axis of the optical assembly  16  so that the next field of the wafer  30  is brought into position relative to the optical assembly  16  and the reticle  28  for exposure. Following this process, the images on the reticle  28  are sequentially exposed onto the fields of the wafer  30 , and then the next field of the wafer  30  is brought into position relative to the optical assembly  16  and the reticle  28 . 
         [0027]    However, the use of the exposure apparatus  10  provided herein is not limited to a photolithography system for semiconductor manufacturing. The exposure apparatus  10 , for example, can be used as an LCD photolithography system that exposes a liquid crystal display device pattern onto a rectangular glass plate or a photolithography system for manufacturing a thin film magnetic head. 
         [0028]    The apparatus frame  12  supports the components of the exposure apparatus  10 . The apparatus frame  12  illustrated in  FIG. 1  supports the reticle stage assembly  18 , the wafer stage assembly  20 , the optical assembly  16  and the illumination system  14  above the mounting base  32 . 
         [0029]    The illumination system  14  includes an illumination source  34  and an illumination optical assembly  36 . The illumination source  34  emits a beam (irradiation) of light energy. The illumination optical assembly  36  guides the beam of light energy from the illumination source  34  to the optical assembly  16 . The beam illuminates selectively different portions of the reticle  28  and exposes the wafer  30 . In  FIG. 1 , the illumination source  34  is illustrated as being supported above the reticle stage assembly  18 . Typically, however, the illumination source  34  is secured to one of the sides of the apparatus frame  12  and the energy beam from the illumination source  34  is directed to above the reticle stage assembly  18  with the illumination optical assembly  36 . 
         [0030]    The optical assembly  16  projects and/or focuses the light passing through the reticle  28  onto the wafer  30 . Depending upon the design of the exposure apparatus  10 , the optical assembly  16  can magnify or reduce the image illuminated from the reticle  28 . The optical assembly  16  need not be limited to a reduction system. It also could be a 1× or magnification system. 
         [0031]    In one embodiment, the optical assembly  16  is secured to the apparatus frame  12  with one or more optical mount isolators  37 . The optical mount isolators  37  inhibit vibration of the apparatus frame  12  from causing vibration to the optical assembly  16 . Each optical mount isolator  37  can include a pneumatic cylinder (not shown) that isolates vibration and an actuator (not shown) that isolates vibration and controls the position with at least two degrees of motion. Suitable optical mount isolators  37  are sold by Integrated Dynamics Engineering, located in Woburn, Mass. For ease of illustration, two spaced apart optical mount isolators  37  are shown as being used to secure the optical assembly  16  to the apparatus frame  12 . However, for example, three spaced apart optical mount isolators  37  can be used to kinematically secure the optical assembly  16  to the apparatus frame  12 . 
         [0032]    The reticle stage assembly  18  holds and positions the reticle  28  relative to the optical assembly  16  and the wafer  30 . In one embodiment, the reticle stage assembly  18  includes a reticle stage  38  that retains the reticle  28  and a reticle stage mover assembly  40  that moves and positions the reticle stage  38  and reticle  28 . 
         [0033]    Somewhat similarly, the device stage assembly  20  holds and positions the wafer  30  with respect to the projected image of the illuminated portions of the reticle  28 . In one embodiment, the device stage assembly  20  includes a device stage  42  that retains the wafer  30 , a device stage base  43  that supports and guides the device stage  42 , and a device stage mover assembly  44  that moves and positions the device stage  42  and the wafer  30  relative to the optical assembly  16  and the device stage base  43 . The device stage  42  is described in more detail below. 
         [0034]    Each stage mover assembly  40 ,  44  can move the respective stage  38 ,  42  with three degrees of freedom, less than three degrees of freedom, or more than three degrees of freedom. For example, in alternative embodiments, each stage mover assembly  40 ,  44  can move the respective stage  38 ,  42  with one, two, three, four, five or six degrees of freedom. The reticle stage mover assembly  40  and the device stage mover assembly  44  can each include one or more movers, such as rotary motors, voice coil motors, linear motors utilizing a Lorentz force to generate drive force, electromagnetic movers, planar motors, or other force movers. 
         [0035]    In photolithography systems, when linear motors (see U.S. Pat. Nos. 5,623,853 or 5,528,118) are used in the device stage assembly or the reticle stage assembly, the linear motors can be either an air levitation type employing air bearings or a magnetic levitation type using Lorentz force or reactance force. Additionally, the stage could move along a guide, or it could be a guideless type stage that uses no guide. The disclosures of U.S. Pat. Nos. 5,623,853 and 5,528,118 are incorporated herein by reference in their entireties. 
         [0036]    Alternatively, one of the stages could be driven by a planar motor that drives the stage by an electromagnetic force generated by a magnet unit having two-dimensionally arranged magnets and an armature coil unit having two-dimensionally arranged coils in facing positions. With this type of driving system, either the magnet unit or the armature coil unit is connected to the stage base and the other unit is mounted on the moving plane side of the stage. 
         [0037]    Movement of the stages as described above generates reaction forces that can affect performance of the photolithography system. Reaction forces generated by the wafer (substrate) stage motion can be mechanically transferred to the floor (ground) by use of a frame member as described in U.S. Pat. No. 5,528,100 and Japanese Laid-Open Patent Application Publication No. 8-136475. Additionally, reaction forces generated by the reticle (mask) stage motion can be mechanically transferred to the floor (ground) by use of a frame member as described in U.S. Pat. No. 5,874,820 and Japanese Laid-Open Patent Application Publication No. 8-330224. The disclosures of U.S. Pat. Nos. 5,528,100 and 5,874,820 and Japanese Laid-Open Patent Application Publication Nos. 8-136475 and 8-330224 are incorporated herein by reference in their entireties. 
         [0038]    The measurement system  22  monitors movement of the reticle  28  and the wafer  30  relative to the optical assembly  16  or some other reference. With this information, the control system  24  can control the reticle stage assembly  18  to precisely position the reticle  28  and the device stage assembly  20  to precisely position the wafer  30 . The design of the measurement system  22  can vary. For example, the measurement system  22  can utilize multiple laser interferometers, encoders, mirrors, and/or other measuring devices. 
         [0039]    The control system  24  is electrically connected to the measurement system  22  and the stage mover assemblies  40 ,  44 , receives information from the measurement system  22 , and controls the stage mover assemblies  40 ,  44  to precisely position the reticle  28  and the wafer  30 . Additionally, the control system  24  can control the operation of the components of the environmental system  26 . The control system  24  can include one or more processors and circuits. 
         [0040]    The environmental system  26  controls the environment in a gap  246  (illustrated in  FIG. 2A ) between the optical assembly  16  and the wafer  30 . The gap  246  includes an imaging field. The imaging field includes the area adjacent to the region of the wafer  30  that is being exposed and the area in which the beam of light energy travels between the optical assembly  16  and the wafer  30 . With this design, the environmental system  26  can control the environment in the imaging field. 
         [0041]    The desired environment created and/or controlled in the gap  246  by the environmental system  26  can vary according to the wafer  30  and the design of the rest of the components of the exposure apparatus  10 , including the illumination system  14 . For example, the desired controlled environment can be a fluid such as water. Alternatively, the desired controlled environment can be another type of fluid. 
         [0042]      FIG. 2A  is a cut-away view of the portion of the exposure apparatus  10  of  FIG. 1 , including the optical assembly  16 , the device stage  42 , and the environmental system  26 .  FIG. 2A  illustrates that the optical assembly  16  includes an optical housing  250 A, a last optical element  250 B, and an element retainer  250 C that secures the last optical element  250 B to the optical housing  250 A. Additionally,  FIG. 2A  illustrates the gap  246  between the last optical element  250 B and the wafer  30 . In one embodiment, the gap  246  is approximately 1 mm. 
         [0043]    In  FIG. 2A , the device stage  42  retains a support  243  (illustrated as a box) that retains and supports the device  30 . For example, the support  243  can be a vacuum type chuck or another type of clamp that retains the device. 
         [0044]    In one embodiment, the environmental system  26  fills the imaging field and the rest of the gap  246  with an immersion fluid  248  (illustrated as circles). The design of the environmental system  26  and the components of the environmental system  26  can be varied. In the embodiment illustrated in  FIG. 2A , the environmental system  26  includes an immersion fluid system  252 , a first recovery system  254 , and a second recovery system  256 . In this embodiment, (i) the immersion fluid system  252  delivers and/or injects the immersion fluid  248  into the gap  246 , (ii) the first recovery system  254  recovers a portion of the immersion fluid  248  that exits the gap  246 , and (iii) the second recovery system  256  recovers immersion fluid  248  that exits the gap  246  that is not captured by the first recovery system  254 . The design of each system  252 ,  254 ,  256  can be varied. 
         [0045]    In one embodiment, the first recovery system  254  recovers more of the immersion fluid  248  that is exiting from the gap  246  than the second recovery system  256 . For example, in alternative embodiments, the first recovery system  254  can recover approximately 10, 20, 30, 40, 50, 60, 70, 80, 90, 95 or 99 percent more than the second recovery system  256 . In one embodiment, the first recovery system  254  captures the majority of the immersion fluid  248  and inhibits the immersion fluid  248  from spilling or dripping onto various parts of the exposure apparatus  10  that surrounds the wafer  30 , and the first recovery system  254  defines a chamber  257  around the gap  246 . 
         [0046]    In another embodiment, the second recovery system  256  recovers more of the immersion fluid  248  that is exiting from the gap  246  than the first recovery system  254 . For example, in alternative embodiments, the second recovery system  256  can recover approximately 10, 20, 30, 40, 50, 60, 70, 80, 90, 95 or 99 percent more than the first recovery system  254 . Alternatively, for example, the environmental system  26  can be designed without the first recovery system  254 . In this embodiment, the second recovery system  256  would recover all of the immersion fluid  248  exiting from the gap  246 . 
         [0047]    The design of the immersion fluid system  252  can vary. For example, the immersion fluid system  252  can inject the immersion fluid  248  at one or more locations at or near the gap  246  and the chamber  257 , the edge of the optical assembly  16 , and/or directly between the optical assembly  16  and the wafer  30 . Further, the immersion fluid system  252  can assist in removing and/or scavenging the immersion fluid  248  at one or more locations at or near the device  30 , the gap  246  and/or the edge of the optical assembly  16 . 
         [0048]    In the embodiment illustrated in  FIG. 2A , the immersion fluid system  252  includes one or more injector nozzles  258  (only one is illustrated) positioned near the perimeter of the optical assembly  16  and an immersion fluid source  260 . In this embodiment, each of the injector nozzles  258  includes a nozzle outlet  262  that is in fluid communication with the immersion fluid source  260 . At the appropriate time, the immersion fluid source  260  provides immersion fluid  248  to the one or more nozzle outlets  262  that is released into the chamber  257 . 
         [0049]    The immersion fluid source  260  can include (i) a fluid reservoir (not shown) that retains the immersion fluid  248 , (ii) a filter (not shown) in fluid communication with the fluid reservoir that filters the immersion fluid  248 , (iii) an aerator (not shown) in fluid communication with the filter that removes any air, contaminants, or gas from the immersion fluid  248 , (iv) a temperature controller (not shown), e.g., a heat exchanger or chiller, in fluid communication with the aerator that controls the temperature of the immersion fluid  248 , (v) a pressure source (not shown), e.g., a pump, in fluid communication with the temperature controller, and (vi) a flow controller (not shown) that has an inlet in fluid communication with the pressure source and an outlet in fluid communication with the nozzle outlets  262  (illustrated in  FIG. 2C ), the flow controller controlling the pressure and flow to the nozzle outlets  262 . Additionally, the immersion fluid source  260  can include (i) a pressure sensor (not shown) that measures the pressure of the immersion fluid  248  that is delivered to the nozzle outlets  262 , (ii) a flow sensor (not shown) that measures the rate of flow of the immersion fluid  248  to the nozzle outlets  262 , and (iii) a temperature sensor (not shown) that measures the temperature of the immersion fluid  248  to the nozzle outlets  262 . The operation of these components can be controlled by the control system  24  (illustrated in  FIG. 1 ) to control the flow rate, temperature and/or pressure of the immersion fluid  248  to the nozzle outlets  262 . The information from these sensors can be transferred to the control system  24  so that the control system  24  can appropriately adjust the other components of the immersion fluid source  260  to achieve the desired temperature, flow and/or pressure of the immersion fluid  248 . 
         [0050]    It should be noted that orientation of the components of the immersion fluid source  260  can be varied. Further, one or more of the components may not be necessary and/or some of the components can be duplicated. For example, the immersion fluid source  260  can include multiple pumps, multiple reservoirs, temperature controllers or other components. Moreover, the environmental system  26  can include multiple immersion fluid sources  260 . 
         [0051]    The rate at which the immersion fluid  248  is pumped into the gap  246  (illustrated in  FIG. 2B ) can vary. For example, the immersion fluid  248  can be supplied to the gap  246  via the nozzle outlets  262  at a rate of between approximately  0 . 5  liters/min. to 1.5 liters/min. 
         [0052]    The type of immersion fluid  248  can be varied to suit the design requirements of the apparatus  10 . In one embodiment, the immersion fluid  248  is a fluid such as de-gassed, de-ionized water. Alternatively, for example, the immersion fluid  248  can be another type of fluid. 
         [0053]      FIG. 2A  also illustrates that the immersion fluid  248  in the chamber  257  sits on top of the wafer  30 . As the wafer  30  moves under the optical assembly  16 , it will drag the immersion fluid  248  in the vicinity of the top surface of the wafer  30  with the wafer  30  into the gap  246 . 
         [0054]    The first recovery system  254  includes (i) a containment frame  264  that surrounds the gap  246  and forms the chamber  257  near the gap  246 , (ii) a frame support  266  that supports the containment frame  264  and (iii) a first recovery device  268 . In one embodiment, the containment frame  264  restricts the flow of the immersion fluid  248  from the gap  246 , assists in maintaining the gap  246  full of the immersion fluid  248 , and facilitates the recovery of the immersion fluid  248  that escapes from the gap  246 . In one embodiment, the containment frame  264  encircles and is positioned entirely around the gap  246  and the bottom of the optical assembly  16 . Further, in one embodiment, the containment frame  264  confines the immersion fluid  248  to a region on the wafer  30  and the device stage  42  under the optical assembly  16 . Alternatively, for example, the containment frame  264  can be positioned around only a portion of the gap  246  or the containment frame  264  can be off-center of the optical assembly  16 . 
         [0055]    In one embodiment, the containment frame  264  is generally annular ring shaped and encircles the gap  246 . Additionally, in this embodiment, the containment frame  264  defines a channel  270  having an open bottom that faces the wafer  30  and the gap  246 . The containment frame  264  can have another shape. For example, the containment frame  264  can be rectangular frame shaped, octagonal frame shaped, oval frame shaped, or another suitable shape. 
         [0056]    The frame support  266  connects and supports the containment frame  264  to the apparatus frame  12 , another structure, and/or the optical assembly  16 , above the wafer  30  and the device stage  42 . In one embodiment, the frame support  266  supports all of the weight of the containment frame  264 . Alternatively, for example, the frame support  266  can support only a portion of the weight of the containment frame  264 . In this embodiment, a fluid bearing (not shown) or another device can be used to support the containment frame relative to the wafer  30 . 
         [0057]    In one embodiment, the frame support  266  can include one or more support assemblies  272 . For example, the frame support  266  can include three spaced apart support assemblies  272  (only two are illustrated in  FIG. 2A ). In this embodiment, each support assembly  272  extends between the optical assembly  16  and the inner side of the containment frame  264 . 
         [0058]    In one embodiment, each support assembly  272  is a mount that rigidly secures the containment frame  264  to the optical assembly  16 . Alternatively, for example, each support assembly can be a flexure that supports the containment frame  264  in a flexible fashion. As used herein, the term “flexure” shall mean a part that has relatively high stiffness in some directions and relatively low stiffness in other directions. In one embodiment, the flexures cooperate (i) to be relatively stiff along the X axis and along the Y axis, and (ii) to be relatively flexible along the Z axis. In this embodiment, the flexures can allow for motion of the containment frame  264  along the Z axis and inhibit motion of the containment frame  264  along the X axis and the Y axis. 
         [0059]    Alternatively, for example, each support assembly  272  can be an actuator that can be used to adjust the position of the containment frame  264  relative to the wafer  30  and the device stage  42 . In this embodiment, the frame support  266  can also include a frame measurement system (not shown) that monitors the position of the containment frame  264 . For example, the frame measurement system can monitor the position of the containment frame  264  along the Z axis, about the X axis, and/or about the Y axis. With this information, the support assemblies  272  can be used to adjust the position of the containment frame  264 . In this embodiment, the support assemblies  272  can actively adjust the position of the containment frame  264 . 
         [0060]      FIG. 2A  also illustrates that the first recovery system  254  can include a transport region  274 . In one embodiment, the transport region  274  is a substrate  275  that is substantially annular disk shaped, encircles the gap  246 , and is substantially concentric with the optical assembly  16 . Alternatively, for example, the transport region  274  can be another shape, including oval frame shaped, rectangular frame shaped or octagonal frame shaped. Still alternatively, for example, the transport region  274  can include a plurality of substrate segments that cooperate to encircle a portion of the gap  246 , and/or a plurality of substantially concentric substrates. 
         [0061]    In this embodiment, the transport region  274  is secured to the containment frame  264  at or near the bottom side and cooperates with the containment frame  264  to form a removal chamber  276  next to and above the transport region  274 . In this embodiment, the transport region  274  captures, retains, and/or absorbs at least a portion of the immersion fluid  248  that flows between the containment frame  264  and the wafer  30  and/or the device stage  42 . The type of material utilized in the transport region  274  can vary. As an example, the transport region  274  can be a material having a plurality of pores that convey the immersion fluid  248  by capillary action. Examples of suitable materials include wick type structures made of metals, glasses, or ceramics. 
         [0062]    The first recovery device  268  is in fluid communication with the transport region  274  and the removal chamber  276 . With this design, the immersion fluid  248  can be captured with the transport region  274  and removed by the first recovery device  268 . In one embodiment, the first recovery device  268  removes the immersion fluid  248  from the top of the transport region  274 , allowing additional immersion fluid  248  to flow into the bottom of the transport region  274 . 
         [0063]    In one embodiment, the first recovery device  268  includes a low pressure source that creates a low pressure in the removal chamber  276 . In this embodiment, the low pressure source can include a pump or vacuum source, and a chamber pressure regulator for precisely controlling the pressure in the removal chamber  276 . The orientation of the components of the first recovery device  268  can be varied. Further, one or more of the components may not be necessary and/or some of the components can be duplicated. For example, the first recovery device  268  can include multiple pumps, multiple reservoirs, valves, or other components. Moreover, the environmental system  26  can include multiple first recovery devices  268 . 
         [0064]    In an alternative embodiment, the control system  24  (illustrated in  FIG. 1 ) could be electrically connected to the transport region  274  and can apply an electrical voltage to the transport region  274 . With this design, the transport region  274  functions as an electrokinetic sponge that captures the immersion fluid  248  that is exiting the gap  246 . In yet another embodiment, the bottom of the containment frame  264  can be open. 
         [0065]      FIG. 2A  illustrates that a frame gap  278  exists between (i) the bottom of the containment frame  264  and the transport region  274 , and (ii) the wafer  30  and/or the device stage  42  to allow for ease of movement of the device stage  42  and the wafer  30  relative to the containment frame  264 . The size of the frame gap  278  can vary. In one embodiment, the frame gap  278  is between approximately 0.1 and 2 mm. In alternative examples, the frame gap  278  can be less than 0.1 mm or greater than 2 mm. 
         [0066]    With this embodiment, most of the immersion fluid  248  is confined within the containment frame  264  and most of the leakage around the periphery is scavenged within the narrow frame gap  278  by the transport region  274 . In this case, when the immersion fluid  248  touches the transport region  274 , it is drawn into the transport region  274  and absorbed. Thus, the transport region  274  prevents any immersion fluid  248  from flowing outside the containment frame  264 . 
         [0067]    It should be noted that in each embodiment, additional transport regions can be added as necessary. 
         [0068]      FIG. 2A  also illustrates that the second recovery system  256  can include a boundary region  280 , a sloped region  282 , a collection region  284 , and a second recovery device  286 . In one embodiment, the sloped region  282  and the collection region  284  are designed to utilize the repetitive acceleration and deceleration of the device stage  42  to move the immersion fluid  248  down the sloped region  282  toward the collection region  284 . 
         [0069]    In  FIG. 2A , the boundary region  280 , the sloped region  282 , and the collection region  284  are disposed in the device stage  42  of the device stage mover assembly  44 . Stated another way, a channel  287  in the device stage  42  defines the sloped region  282 , and the collection region  284 . Alternatively, for example, one or more of the regions  280 ,  282 ,  284  can be incorporated into an additional component that is secured to the device stage  42 . 
         [0070]      FIG. 2B  illustrates a portion of the device  30  and the device stage  42  of  FIG. 2A .  FIG. 2C  illustrates a top plan view of the device stage  42  and the device  30 .  FIGS. 2B and 2C  also illustrate the boundary region  280 , the sloped region  282 , and the collection region  284 . 
         [0071]    Referring to  FIGS. 2A-2C , the boundary region  280  provides a transition zone between the wafer  30  and sloped region  282 . In one embodiment, the boundary region  280  is an annular shaped area that is on the same plane as the bottom of the wafer  30 . Stated another way, the boundary region  280  has a top surface that is approximately the same height along the Z axis as the bottom of the wafer  30 . With this design, the top surface can cooperate with the containment frame  264  to contain the immersion fluid  248  under the optical assembly  16  when the edge of the wafer  30  is moved under the optical assembly  16 . Alternatively, for example, and as shown in FIG.  2 B′, the top surface of boundary region  280  can be approximately the same height along the Z axis as the top of the wafer  30 . As another alternative, the top surface  280  could be below the wafer  30 . In the embodiment illustrated in  FIGS. 2A-2C , the boundary region  280  is positioned above the sloped region  282  and the collection region  284  along the Z axis. 
         [0072]    The sloped region  282  extends between the boundary region  280  and the collection region  284  and facilitates movement of the immersion fluid  248  that escapes from the gap  246  away from the wafer  30 . In one embodiment, the sloped region  282  is generally annular shaped and is at an acute angle relative to the boundary region  280  and the X and Y axes. Stated another way, the sloped region  282  can taper downward from the boundary region  280 . For example, the sloped region  282  can be at an angle  291 A of at least approximately 2 degrees or more relative to the boundary region  280 . In alternative embodiments, the sloped region  282  can be at an angle  291 A of at least approximately 1, 2, 3, 5, 10, or 20 degrees relative to the boundary region  280  or the bottom or top of the wafer  30 . 
         [0073]    In one embodiment, the sloped region  282  is positioned near the wafer  30 . In alternative embodiments, the sloped region  282  is within approximately 5, 10, 20, 30, 40 or 50 mm of the wafer  30 . Alternatively, the sloped region  282  can be closer than 5 mm or greater than 50 mm from the wafer  30 . 
         [0074]    Further, in one embodiment, a drop down region  288  is positioned between the boundary region  280  and the sloped region  282 . The drop down region  288  inhibits immersion fluid  248  near the top of the sloped region  282  from being propelled back onto the boundary region  280  when the device stage  42  is accelerated. In  FIG. 2A , the drop down region  288  is at an acute angle relative to the Z axis (perpendicular to the boundary region  280  and the wafer  30 ). In alternative embodiments, the drop down region  288  can be at an angle  291 B of at least approximately 2, 5, 10, or 15 degrees relative to the Z axis. Alternatively, for example, the drop down region  288  can extend along the Z axis substantially perpendicular to the boundary region  280 . 
         [0075]    The collection region  284  collects the immersion fluid  248  that flows down the sloped region  282 . In one embodiment, the collection region  284  is positioned below the sloped region  282 . In one embodiment, the collection region  284  includes one or more channel outlets  290  that are in fluid communication with the second recovery device  286  (illustrated in  FIG. 2A ). 
         [0076]    The second recovery device  286  recovers immersion fluid  248  from the collection region  284 . In one embodiment, the second recovery device  286  includes a low pressure source that creates a low pressure in the collection region  284 . In this embodiment, the low pressure source can include a pump or vacuum source, and a pressure regulator for precisely controlling the pressure in the collection region  284 . One or more of the components may not be necessary and/or some of the components can be duplicated. For example, the second recovery device  286  can include multiple pumps, multiple reservoirs, valves, or other components. 
         [0077]      FIG. 3A  illustrates a top view of the device  30  and another embodiment of the device stage  342 . In this embodiment, the device stage  342  is somewhat similar to the corresponding component described above. However, in this embodiment, the sloped region  382  is slightly different. More specifically, in this embodiment, the sloped region  382  includes a first subregion  392  having a first characteristic  393  (illustrated as shading) and a second subregion  394  having a second characteristic  395  (illustrated as shading) that is different than the first characteristic  393 . 
         [0078]    The design of the first and second subregions  392 ,  394  can be varied to facilitate one-way movement of the immersion fluid  248  (illustrated as a drop) down the sloped region  382  toward the collection region  384  (illustrated in phantom). In the embodiment illustrated in  FIG. 3A , the first subregion  392  is positioned above the second subregion  394 . Further, in this embodiment, a transition  396  between the first subregion  392  and the second subregion  394  is defined by a plurality of interconnected arch shaped segments that define a plurality of spaced apart sharp points  397 . Stated another way, at the transition  396 , the second subregion  394  includes a plurality of interconnected, adjacent, concave areas and the first subregion  392  includes a plurality of interconnected, adjacent, convex areas. 
         [0079]    The design of the first characteristic  393  and the second characteristic  395  can vary. In one embodiment, (i) the first characteristic  393  is a first surface tension modifying coating that coats the first subregion  392  and modifies movement of the immersion fluid  248  across the first subregion  392 , and (ii) the second characteristic  395  is a second surface tension modifying coating that coats the second subregion  394  and modifies movement of the immersion fluid  248  across the second subregion  394 . 
         [0080]    In one embodiment, (i) the first characteristic  393  is a hydrophobic type coating that repels the immersion fluid  248 , and causes the immersion fluid  248  to form beads on the first subregion  392  and not wet the first subregion  392  and (ii) the second characteristic  395  is a hydrophilic type coating that can cause the immersion fluid  248  to wet the second subregion  394  and not bead up on the second subregion  394 . With this design, in certain embodiments, immersion fluid  248  may actually act as a sheet on the second subregion  394  that can be controllably moved toward the collection region  284 . 
         [0081]    Alternatively, for example, the coatings in the first and second subregions  392 ,  394  can be switched, the same coating can be applied to the first and second subregions  392 ,  394 , or the first and second subregions  392 ,  394  may not be coated. Still alternatively, the first and second subregions  392 ,  394  can be at different slopes or levels. 
         [0082]      FIG. 3B  illustrates a portion of the device stage  342  from  FIG. 3A . More specifically,  FIG. 3B  illustrates that the sharp points  397  (only one shown) in conjunction with the first characteristic  395  will act to inject the immersion fluid  248  toward the second subregion  394  and the collection region  384  when the device stage  342  is accelerated into this particular point  397 . This is because the point  397  concentrates the pressure of the immersion fluid  248 , and the immersion fluid  248  will break free of the first subregion  392  when the immersion fluid  248  thickness is sufficient. 
         [0083]    Referring back to  FIG. 3A , because there are no sharp points between the first subregion  392  and the device  30 , there is less tendency for the immersion fluid  248  to move from the first subregion  392  back toward the device  30 . The net effect is a constant movement of the immersion fluid  248  from the inner diameter of the first subregion  392  to the outer diameter of the first subregion  392 , and the movement of the immersion fluid  248  from the first subregion  392  to the second subregion  394  as the immersion fluid  248  is broken free at the points  397 . 
         [0084]      FIG. 4  illustrates a top plan view of the device  30  and another embodiment of a device stage  442  having features of the invention. In this embodiment, the device stage  442  is somewhat similar to the device stage  342  illustrated in  FIGS. 3A and 3B  and described above. However, in this embodiment, the sloped region  482  includes one or more collection apertures  498  strategically located to enhance the collection of the immersion fluid  248 . The collection apertures  498  can be in fluid communication with a second recovery device  486  that creates a low pressure in the collection apertures  498  to draw the immersion fluid  248  at the collection apertures  498 . 
         [0085]    In one embodiment, one collection aperture  498  is positioned near each point  497 . Alternatively, for example, the collection apertures  498  can be positioned in other locations in the sloped region  482 . 
         [0086]    In this embodiment, the collection apertures  498  can be designed to collect all of the immersion fluid  248  in the sloped region  482 . With this design, a minimal amount of immersion fluid  248  is collected in the collection region  484 . Alternatively, for example, the collection apertures  498  can be designed to collect only a portion of the immersion fluid  248  in the sloped region  482 . With this design, the collection region  484  collects any immersion fluid  248  not collected by the collection apertures  498 . 
         [0087]      FIG. 5A  is an enlarged side cut-away view of a portion of the device  30  and another embodiment of a device stage  542 , and  FIG. 5B  is a top plan view of the device  30  and the device stage  542  of  FIG. 5A . 
         [0088]    In this embodiment, the sloped region  582  includes a first subregion  592  and a second subregion  594 . Further, in this embodiment, the first subregion  592  is at a first angle  598 A relative to the X and Y axes and a top or bottom of the device  30 , the second subregion  594  is at a second angle  598 B relative to the X and Y axes and the top or bottom of the device  30 , and the first angle  598 A may be the same or different than the second angle  598 B. In alternative examples, the first angle  598 A can be approximately 10, 20, 30, 40 or 45 degrees and the second angle  598 B can be approximately 10, 20, 30, 40, or 45 degrees. In this embodiment, the mechanical geometry of the sloped region  582  collects and controls the flow of the immersion fluid. 
         [0089]    In one embodiment, the device stage assembly  520  also includes a first collection region  584 A that is in fluid communication with the first subregion  592 , a second collection region  584 B that is in fluid communication with the second subregion  594 , and a second recovery device  586  that removes immersion fluid from the collection regions  584 A,  584 B. In one embodiment, the second recovery device  586  includes a low pressure source that creates a low pressure in the collection regions  584 A,  584 B. 
         [0090]    In this embodiment, the system can be designed so that the first collection region  584 A collects all of the immersion fluid  248 . With this design, no immersion fluid  248  is collected in the second collection region  584 B. Stated another way, the second collection region  584 B can be optional, as it may not be needed, depending on the volume of immersion fluid  248  to be collected, and on the device stage  542  acceleration and deceleration. Alternatively, for example, the first collection region  584 A can only collect a portion of the immersion fluid  248  in the sloped region  582 . With this design, the second collection region  584 B collects any immersion fluid  248  not collected by the first collection region  584 A. 
         [0091]    Also, in this embodiment, the nature of the coatings of the first and second subregions  592 ,  594  may be less important. For example, the coatings of one or both of the first and second subregions  592 ,  594  can be considered optional. 
         [0092]    Semiconductor devices can be fabricated using the above described systems, by the process shown generally in  FIG. 6A . In step  601  the device&#39;s function and performance characteristics are designed. Next, in step  602 , a mask (reticle) having a pattern is designed according to the previous designing step, and in a parallel step  603  a wafer is made from a silicon material. The mask pattern designed in step  602  is exposed onto the wafer from step  603  in step  604  by a photolithography system described hereinabove in accordance with the invention. In step  605 , the semiconductor device is assembled (including the dicing process, bonding process and packaging process). Finally, the device is inspected in step  606 . 
         [0093]      FIG. 6B  illustrates a detailed flowchart example of the above-mentioned step  604  in the case of fabricating semiconductor devices. In  FIG. 6B , in step  611  (oxidation step), the wafer surface is oxidized. In step  612  (CVD step), an insulation film is formed on the wafer surface. In step  613  (electrode formation step), electrodes are formed on the wafer by vapor deposition. In step  614  (ion implantation step), ions are implanted in the wafer. The above mentioned steps  611 - 614  form the preprocessing steps for wafers during wafer processing, and selection is made at each step according to processing requirements. 
         [0094]    At each stage of wafer processing, when the above-mentioned preprocessing steps have been completed, the following post-processing steps are implemented. During post-processing, first, in step  615  (photoresist formation step), photoresist is applied to a wafer. Next, in step  616  (exposure step), the above-mentioned exposure device is used to transfer the circuit pattern of a mask (reticle) to a wafer. Then in step  617  (developing step), the exposed wafer is developed, and in step  618  (etching step), parts other than residual photoresist (exposed material surface) are removed by etching. In step  619  (photoresist removal step), unnecessary photoresist remaining after etching is removed. 
         [0095]    Multiple circuit patterns are formed by repetition of these preprocessing and post-processing steps. 
         [0096]    While the particular exposure apparatus  10  as shown and described herein is fully capable of obtaining the objects and providing the advantages previously stated, it is to be understood that it is merely illustrative of the embodiments of the invention, and that no limitations are intended to the details of construction or design herein shown.