Patent Abstract:
A lithographic projection apparatus that is arranged to project a pattern from a patterning device onto a substrate using a projection system has a liquid supply system arranged to supply a liquid to a space between the projection system and the substrate. The apparatus also includes a liquid collecting system that includes a liquid collection member having a permeable member through which a liquid is collected from a surface of an object opposite to the liquid collection member, wherein the permeable member has a plurality of passages that generate a capillary force.

Full Description:
RELATED APPLICATIONS 
     This is a Divisional of U.S. patent application Ser. No. 11/236,713 filed Sep. 28, 2005, which is a Continuation of International Application No. PCT/US2004/009994 filed Apr. 1, 2004, which claims the benefit of U.S. Provisional Patent Application No. 60/462,112 filed on Apr. 10, 2003 and U.S. Provisional Patent Application No. 60/485,033 filed on Jul. 2, 2003. The disclosures of these applications are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     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. 
     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 
     The invention is directed to an environmental system for controlling an environment in a gap between an optical assembly and a device that is retained by a device stage. The environmental system includes an immersion fluid source and a transport region that is positioned near the device. The immersion fluid source delivers an immersion fluid that enters the gap. The transport region captures immersion fluid that is exiting the gap. With this design, in certain embodiments, the invention avoids the use of direct vacuum suction on the device that could potentially distort the device and/or the optical assembly. 
     In one embodiment, the environmental system includes a fluid barrier that is positioned near the device and that encircles the gap. Furthermore, the fluid barrier can maintain the transport region near the device. 
     In one embodiment, the environmental system includes a fluid removal system that removes immersion fluid from near the transport region. In another embodiment, the fluid removal system can direct a removal fluid that removes immersion fluid from the transport region. In this embodiment, the removal fluid can be at a removal fluid temperature that is higher than an immersion fluid temperature of the immersion fluid. 
     In one embodiment, the transport region is a substrate that includes a plurality of passages for collecting the immersion fluid near the transport region. As an example, the transport region can be made of a material that conveys the immersion fluid by capillary action. In this embodiment, the passages can be a plurality of pores. In an alternative embodiment, the passages can be a plurality of spaced apart transport apertures that extend through the transport region. 
     The present 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 
       The invention will be described in conjunction with exemplary embodiments in which like reference numerals designate like elements, and in which: 
         FIG. 1  is a side illustration of an exposure apparatus having features of the invention; 
         FIG. 2A  is a perspective view of a portion of the exposure apparatus of  FIG. 1 ; 
         FIG. 2B  is a cut-away view taken on line  2 B- 2 B of  FIG. 2A ; 
         FIG. 2C  is an enlarged detailed view taken on line  2 C- 2 C in  FIG. 2B ; 
         FIG. 2D  is an enlarged detailed view of another embodiment of a portion of an exposure apparatus; 
         FIG. 3A  is a side illustration: of an immersion fluid source having features of the invention; 
         FIG. 3B  is a side illustration of a fluid removal system having features of the invention; 
         FIG. 3C  is a side illustration of another embodiment of a fluid removal system having features of the invention; 
         FIG. 3D  is a side illustration of another embodiment of a fluid removal system having features of the invention; 
         FIG. 4  is an enlarged cut-away view of a portion of another embodiment of an exposure apparatus; 
         FIG. 5A  is an enlarged cut-away view of a portion of another embodiment of an exposure apparatus; 
         FIG. 5B  is an enlarged detailed view taken on line  5 B- 5 B in  FIG. 5A ; 
         FIG. 6A  is a flow chart that outlines a process for manufacturing a device in accordance with the invention; and 
         FIG. 6B  is a flow chart that outlines device processing in more detail. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       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 . 
     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. 
     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  is also 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. 
     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. 
     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 wafer 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 . 
     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. 
     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 . 
     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 . 
     The illumination source  34  can be a g-line source (436 nm), an i-line source (365 nm), a KrF excimer laser (248 nm), an ArF excimer laser (193 nm) or a F 2  laser (157 nm). Alternatively, the illumination source  34  can generate charged particle beams such as an x-ray or an electron beam. For instance, in the case where an electron beam is used, thermionic emission type lanthanum hexaboride (LaB 6 ) or tantalum (Ta) can be used as a cathode for an electron gun. Furthermore, in the case where an electron beam is used, the structure could be such that either a mask is used or a pattern can be directly formed on a substrate without the use of a mask. 
     The optical assembly  16  projects and/or focuses the light passing through the reticle  28  to the wafer  30 . Depending upon the design of the exposure apparatus  10 , the optical assembly  16  can magnify or reduce the image illuminated on the reticle  28 . The optical assembly  16  need not be limited to a reduction system. It also could be a 1× or magnification system. 
     When far ultra-violet rays such as the excimer laser is used, glass materials such as quartz and fluorite that transmit far ultra-violet rays can be used in the optical assembly  16 . When the F 2  type laser or x-ray is used, the optical assembly  16  can be either catadioptric or refractive (a reticle should also preferably be a reflective type), and when an electron beam is used, electron optics can consist of electron lenses and deflectors. The optical path for the electron beams should be in a vacuum. 
     Also, with an exposure device that employs vacuum ultra-violet radiation (VUV) of wavelength 200 nm or lower, use of the catadioptric type optical system can be considered. Examples of the catadioptric type of optical system include Japanese Laid-Open Patent Application Publication No. 8-171054 and its counterpart U.S. Pat. No. 5,668,672, as well as Japanese Laid-Open Patent Application Publication No. 10-20195 and its counterpart U.S. Pat. No. 5,835,275. In these cases, the reflecting optical device can be a catadioptric optical system incorporating a beam splitter and concave mirror. Japanese Laid-Open Patent Application Publication No. 8-334695 and its counterpart U.S. Pat. No. 5,689,377 as well as Japanese Laid-Open Patent Application Publication No. 10-3039 and its counterpart U.S. Pat. Application No. 873,605 (Application Date: Jun. 12, 1997) also use a reflecting-refracting type of optical system incorporating a concave mirror, etc., but without a beam splitter, and can also be employed with this invention. The disclosures of the above-mentioned U.S. patents and Japanese Laid-Open patent applications publications are incorporated herein by reference in their entireties. 
     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 . 
     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 . 
     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. 
     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. 
     In photolithography systems, when linear motors (see U.S. Pat. Nos. 5,623,853 or 5,528,118) are used in the wafer 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. 
     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. 
     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. 
     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. 
     The control system  24  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. 
     The environmental system  26  controls the environment in a gap  246  (illustrated in  FIG. 2B ) 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. 
     The desired environment created and/or controlled in the gap  246  by the environmental system  26  can vary accordingly 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. 
       FIG. 2A  is a perspective view of the wafer  30 , and a portion of the exposure apparatus  10  of  FIG. 1  including the optical assembly  16 , the device stage  42 , and the environmental system  26 . 
       FIG. 2B  is a cut-away view of the portion of the exposure apparatus  10  of  FIG. 2A , including the optical assembly  16 , the device stage  42 , and the environmental system  26 .  FIG. 2B  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. 2B  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. 
     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. 2B , the environmental system  26  includes an immersion fluid system  252 , a fluid barrier  254 , and a transport region  256 . In this embodiment, (i) the immersion fluid system  252  delivers and/or injects the immersion fluid  248  into the gap  246 , removes the immersion fluid  248  from or near the transport region  256 , and/or facilitates the movement of the immersion fluid  248  through the transport region  256 , (ii) the fluid barrier  254  inhibits the flow of the immersion fluid  248  away from near the gap  246 , and (iii) the transport region  256  transfers and/or conveys the immersion fluid  248  flowing from the gap  246 . The fluid barrier  254  also forms a chamber  257  near the gap  246 . 
     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 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 . 
     In the embodiment illustrated in  FIG. 2B , 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 .  FIG. 2C  illustrates one injector nozzle  258  in more detail. 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 . 
       FIGS. 2B and 2C  also illustrate that the immersion fluid  248  in the chamber  257  sits on top of the wafer  30 . The immersion fluid  248  flows into the gap  246 . Further, 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 . 
     In one embodiment, the fluid barrier  254  forms the chamber  257  around the gap  246 , 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 fluid barrier  254  encircles and is positioned entirely around the gap  246  and the bottom of the optical assembly  16 . Further, in one embodiment, the fluid barrier  254  confines the immersion fluid  248  to a region on the wafer  30  and the device stage  42  centered on the optical assembly  16 . Alternatively, for example, the fluid barrier  254  can be positioned around only a portion of the gap  246  or the fluid barrier  254  can be off-center of the optical assembly  16 . 
     In the embodiment illustrated in  FIGS. 2B and 2C , the fluid barrier  254  includes a containment frame  264 , and a frame support  268 . In this embodiment, the containment frame  264  is generally annular ring shaped and encircles the gap  246 . Additionally, in this embodiment, the containment frame  264  includes a top side  270 A, an opposed bottom side  270 B that faces the wafer  30 , an inner side  270 C that faces the gap  246 , and an outer side  270 D. Moreover, in this embodiment, the fluid barrier  254  includes a channel  272  for receiving the transport region  256 . As an example, the channel  272  can be annular shaped. 
     The terms top and bottom are used merely for convenience, and the orientation of the containment frame  264  can be rotated. It should also be noted that 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. 
     The frame support  268  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  268  supports all of the weight of the containment frame  264 . Alternatively, for example, the frame support  268  can support only a portion of the weight of the containment frame  264 . In one embodiment, the frame support  268  can include one or more support assemblies  274 . For example, the frame support  268  can include three spaced apart support assemblies  274  (only two are illustrated in  FIG. 2B ). In this embodiment, each support assembly  274  extends between the optical assembly  16  and the inner side  270 C of the containment frame  264 . 
     In one embodiment, each support assembly  274  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. 
     Alternatively, for example, each support assembly  274  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  268  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  274  can be used to adjust the position of the containment frame  264 . In this embodiment, the support assemblies  274  can actively adjust the position of the containment frame  264 . 
       FIGS. 2B and 2C  also illustrate the transport region  256  in more detail. In this embodiment, the transport region  256  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 substrate  275  can be another shape, including oval frame shaped, rectangular frame shaped or octagonal frame shaped. Still alternatively, for example, the transport region  256  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. 
     The dimensions of the transport region  256  can be selected to achieve the desired immersion fluid recovery rate. 
     Further, in this embodiment, the transport region  256  is secured to the containment frame  264  at or near the bottom side  270 B of the containment frame  264  and cooperates with the containment frame  264  to form a removal chamber  276  next to and above the transport region  256 . Moreover, as illustrated in  FIG. 2C , the transport region  256  includes a first surface  278 A that is adjacent to the removal chamber  276  and an opposite second surface  278 B that is adjacent to the device  30  and the gap  246 . 
     In this embodiment, the transport region  256  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  256  can vary. In one embodiment, the substrate  275  includes a plurality of passages  280 . For example, the passages  280  can be relatively small and tightly packed. 
     As an example, the transport region  256  can be a porous material having a plurality of pores and/or interstices that convey the immersion fluid  248  by capillary action. In this embodiment, the passages  280  can be small enough so that capillary forces draw the immersion fluid  248  into the pores. Examples of suitable materials include wick type structures made of metals, glasses, or ceramics&#39;. Examples of suitable wick type structures include any material with a network of interconnected, small passages, including, but not limited to, woven fiberglass, sintered metal powders, screens, wire meshes, or grooves in any material. The transport region  256  can be hydrophilic. 
     In one embodiment, the transport region  256  has a pore size of between approximately 20 and 200 microns. In alternative embodiments, the transport region  256  can have a porosity of at least approximately 40, 80, 100, 140, 160 or 180. 
     In certain embodiments, a relatively higher flow capacity is required. To accommodate higher flow, larger porosity material may be necessary for the transport region  256 . The choice for the porosity of the transport region  256  depends on the overall flow rate requirement of the transport region  256 . Larger overall flow rates can be achieved by using a transport region  256  having a larger porosity, decreasing the thickness of the transport region  256 , or increasing the surface area of the transport region  256 . In one embodiment, with a flow rate requirement of 0.3-1.0 L/min in immersion lithography, pores size of 40-150 μm can be used to cover a 30-150 cm 2  area for immersion fluid  248  recovery. The type and specifications of the porous material also depends on the application and the properties of the immersion fluid  248 . 
     Referring back to  FIG. 2B , in certain embodiments, the transport region  256  has a limited capacity to absorb the immersion fluid  248 . In one embodiment, the immersion fluid system  252  includes a fluid removal system  282  that removes immersion fluid  248  from or near the transport region  256  and that is in fluid communication with the transport region  256  and the removal chamber  276 . With this design, the immersion fluid  248  can be captured with the transport region  256  and removed by the fluid removal system  276 . 
     In one embodiment, the fluid removal system  282  removes the immersion fluid  248  from the top first surface  278 A of the transport region  256  allowing additional immersion fluid  248  to flow into the bottom, second surface  278 B of the transport region  256 . For example, the fluid removal system  282  can create a pressure differential across the transport region  256 . In one example, the fluid removal system  282  causes the pressure at the first surface  278 A to be lower than the pressure at the second surface  278 B. 
     The removal of the immersion fluid  248  can be accomplished in several different ways and a number of embodiments of the fluid removal system  282  are described below. 
       FIG. 2C  illustrates that a frame gap  284  exists between (i) the bottom side  270 B of the containment frame  264  and the second surface  278 B of the transport region  256 , 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  284  can vary. In one embodiment, the frame gap  284  is between approximately 0.1 and 2 mm. In alternative examples, the frame gap  284  can be approximately 0.05, 0.1, 0.2, 0.5, 1, 1.5, 2, 3, or 5 mm. 
     With this embodiment, most of the immersion fluid  248  is confined within the fluid barrier  254  and most of the leakage around the periphery is scavenged within the narrow frame gap  284  by the transport region  256 . In this case, when the immersion fluid  248  touches the transport region  256 , it is drawn into the transport region  256  and absorbed. Thus, the transport region  256  inhibits any immersion fluid  248  from flowing outside the ring. 
       FIG. 2D  illustrates a cut-away view of a portion of another embodiment of an exposure apparatus  10 D that is somewhat similar to the embodiment illustrated in  FIG. 2C . However, in  FIG. 2D , the device  30 D and/or the stage  42 D is closer to the bottom side  270 BD of the inner side  270 CD and/or the outer side  270 DD of the containment frame  264 D than the second surface  278 DB of the transport region  256 D. Stated another way, the distance between the bottom side  270 BD and the device  30 D and/or the stage  42 D is less than the distance between the second surface  278 DB and the device  30 D and/or the stage  42 D. 
       FIG. 3A  illustrates one embodiment of the immersion fluid source  260 . In this embodiment, the immersion fluid source  260  includes (i) a fluid reservoir  386 A that retains the immersion fluid  248 , (ii) a filter  386 B in fluid communication with the fluid reservoir  386 A that filters the immersion fluid  248 , (iii) a de-aerator  386 C in fluid communication with the filter  386 B that removes any air, contaminants, or gas from the immersion fluid  248 , (iv) a temperature controller  386 D, e.g., a heat exchanger or chiller, in fluid communication with the de-aerator  386 C that controls the temperature of the immersion fluid  248 , (v) a pressure source  386 E, e.g., a pump, in fluid communication with the temperature controller  386 D, and (vi) a flow controller  386 F that has an inlet in fluid communication with the pressure source  386 E and an outlet in fluid communication with the nozzle outlets  262  (illustrated in  FIG. 2C ), the flow controller  386 F controlling the pressure and flow to the nozzle outlets  262 . 
     Additionally, the immersion fluid source  260  can include (i) a pressure sensor  386 G that measures the pressure of the immersion fluid  248  that is delivered to the nozzle outlets  262 , (ii) a flow sensor  386 H that measures the rate of flow of the immersion fluid  248  to the nozzle outlets  262 , and (iii) a temperature sensor  386 I 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  386 G- 386 I 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 . 
     The 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 . 
     The rate at which the immersion fluid  248  is pumped into the gap  246  (illustrated in  FIG. 2B ) can vary. In one embodiment, the immersion fluid  248  is supplied to the gap  246  via the nozzle outlets  262  at a rate of between approximately 0.5 liters/min to 2 liters/min. However, the rate can be greater or less than these amounts. 
     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, such as a per-fluorinated polyether (PFPE) such as Fomblin oil. 
       FIG. 3B  illustrates a first embodiment of the fluid removal system  382 B and an illustration of a portion of the fluid barrier  254 , the transport region  256 , the wafer  30 , and the immersion fluid  248 . The fluid removal system  382 B is also referred to herein as a pressure system. In one embodiment, the fluid removal system  382 B creates and/or applies a transport pressure to the first surface  278 A of the transport region  256 . In this embodiment, the fluid removal system  382 B maintains the transport pressure at the first surface  278 A of the transport region  256  so that a pressure differential exists between the first surface  278 A and the second surface  278 B. In alternative embodiments, the fluid removal system  382 B controls the pressure in the removal chamber  276  so that the transport pressure at the first surface  278 A is approximately −10, −100, −500, −1000, −2000, −5000, −7000 or −10,000 Pa gage. 
     In  FIG. 3B , the fluid removal system  382 B includes (i) a low pressure source  390 BA that creates a low chamber pressure in the removal chamber  276 , and (ii) a recovery reservoir  390 BC that captures immersion fluid  248  from the removal chamber  276 . In this embodiment, the low pressure source  390 BA can include a pump or vacuum source  390 BD, and a chamber pressure regulator  390 BE for precisely controlling the chamber pressure in the chamber  276 . In alternative embodiments, for example, the chamber pressure is controlled to be approximately −10, −100, −500, −1000, −2000, −5000, −7000 or −10,000 Pa gage. The chamber pressure regulator  390 BE can be controlled by the control system  24  to control the chamber pressure. 
       FIG. 3C  illustrates another embodiment of the fluid removal system  382 C and an illustration of a portion of the fluid barrier  254 , the transport region  256 , the wafer  30 , and the immersion fluid  248 . In this embodiment, the fluid removal system  382 C forces a dry removal fluid  396  (illustrated as triangles), e.g., air through the removal chamber  276  and across the top first surface  278 A of the transport region  256 . The removal fluid  396  will dry the top surface  278 A of the transport region  256 , pumping immersion fluid  248  out of the transport region  256 . The removal fluid  396  can be heated in some cases, improving the flow of the immersion fluid  248  into the dry removal fluid  396 . Stated another way, in one embodiment, the removal fluid  396  is at a removal fluid temperature that is higher than an immersion fluid temperature of the immersion fluid  248 . 
     In  FIG. 3C , the fluid removal system  382 C includes (i) a fluid source  396 A of the pressurized drying removal fluid  396 , (ii) a temperature controller  396 B that controls the temperature of the drying removal fluid  396 , (iii) a flow sensor  396 C that measures the flow of the drying removal fluid  396 , and (iv) a temperature sensor  396 D that measures the temperature of the drying removal fluid  396 . The fluid source  396 A can include a pump controlled by the control system  24 , and the temperature controller  396 B can be a heater that is controlled by the control system  24 . 
       FIG. 3D  illustrates yet another embodiment of the fluid removal system  382 D and an illustration of a portion of the fluid barrier  254 , the transport region  256 , the wafer  30 , and the immersion fluid  248 . In this embodiment, the transport region  256  is extended outside the fluid barrier  254 . Further, the fluid removal system  382 C includes a heat source  397  that directs a heated fluid  396 F (illustrated as triangles) at the first surface  278 A of the transport region  256 , causing the immersion fluid  248  to boil out of the transport region  256  and be captured. 
     The orientation of the components of the fluid removal systems  382 B- 382 D illustrated in  FIGS. 3B-3D  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, each of the fluid removal systems  382 B,  382 C,  382 D can include multiple pumps, multiple reservoirs, valves, or other components. Moreover, the environmental system  26  can include multiple fluid removal systems  382 B,  382 C,  382 D. 
       FIG. 4  is an enlarged view of a portion of another embodiment of the environmental system  426 , a portion of the wafer  30 , and a portion of the device stage  42 . In this embodiment, the environmental system  426  is somewhat similar to the corresponding component described above and illustrated in  FIGS. 2A-2C . However, in this embodiment, the transport region  456  is slightly different. In particular, in this embodiment, the passages  480  (only two are illustrated) in the substrate  475  of the transport region  456  are a plurality of spaced apart transport apertures that extend substantially transversely through the substrate  475  between the first surface  478 A and the second surface  478 B. 
     In this embodiment, for example, the substrate  475  can be made of a material such as glass or other hydrophilic materials. In one embodiment, the transport apertures  480  can have a diameter of between approximately 0.1 and 0.2 mm. However, in certain embodiments, the transport apertures can be larger or smaller than these amounts. 
     With this design, for example, one or more of the fluid removal systems  382 B,  382 C (illustrated in  FIGS. 3B and 3C ) can be used to apply a vacuum or partial vacuum on the transport apertures  480 . The partial vacuum draws the immersion fluid  248  through the transport region  456 . 
       FIG. 5A  is a cut-away view of a portion of another embodiment of the exposure apparatus  510 , including the optical assembly  516 , the device stage  542 , and the environmental system  526 .  FIG. 5A  also illustrates the wafer  30 , the gap  546 , and that the immersion fluid  548  fills the gap  546 .  FIG. 5B  illustrates an enlarged portion of  FIG. 5A  taken on line  5 B- 5 B. 
     In this embodiment, the environmental system  526  again includes an immersion fluid system  552 , a fluid barrier  554 , and a transport region  556  that are somewhat similar to the corresponding components described above. In this embodiment, the fluid barrier  554  includes a containment frame  564  that forms a chamber  557  around the gap  546 , and a frame support  568  that connects and supports the containment frame  564  to the apparatus frame  12 . However, in this embodiment, the containment frame  564  includes (i) an annular shaped first channel  581  that defines a nozzle outlet  562  that is in fluid communication with an immersion fluid source  560  of the immersion fluid system  552 ; (ii) an annular shaped second channel  583 , (iii) an annular shaped third channel  585 , and (iv) an annular shaped fourth channel  587  for receiving the transport region  556 . In this embodiment, the channels  581 ,  583 ,  585 ,  587  are approximately concentric and are centered about the optical assembly  516 . Further, in this embodiment, the second channel  583  encircles the first channel  581 , the third channel  585  encircles the second channel  583 , and the fourth channel  587  encircles the third channel  585 . However, the shape, orientation, and/or position of the channels  581 ,  583 ,  585 ,  587  can be changed. 
     In one embodiment, the immersion fluid system  552  provides the immersion fluid  548  to the first channel  581  and the nozzle outlet  562  that is released into the chamber  557 . The transport region  556  cooperates with the containment frame  564  to form a removal chamber  576  next to and above the transport region  556 . Moreover, the transport region  556  includes a first surface  578 A that is adjacent to the removal chamber  576  and an opposite second surface  578 B that is adjacent to the device  30  and the gap  546 . 
     In this embodiment, the third channel  585  is in fluid communication with a first removal system  528 A. In one embodiment, the first removal system  528 A creates a vacuum or partial vacuum in the third channel  585  that pulls and/or draws the immersion fluid  548  into the third channel  585 . For example, in alternative embodiments, the first removal system  528 A can maintain the pressure in the third channel  585  at approximately −10, −100, −500, −1000, −2000, −5000, −7000 or −10,000 Pa gage. 
     Further, in this embodiment, the fourth channel  587  is in fluid communication with a second removal system  528 B. In this embodiment, the second removal system  528 B removes the immersion fluid  548  from the top first surface  578 A of the transport region  556 , allowing additional immersion fluid  548  to flow into the bottom, second surface  578 B of the transport region  556 . 
     In one embodiment, the design of the first removal system  528 A can be somewhat similar to the design of one of the removal systems  382 B,  382 C illustrated in  FIGS. 3B-3D  and/or the design of the second removal system  528 B can be somewhat similar to one of the designs illustrated in  FIGS. 3B-3D . 
     In one embodiment, the majority of the immersion fluid  548  exiting from the gap  546  is recovered through the third channel  585 . For example, the third channel  585  can recover between approximately 80-90 percent of the immersion fluid  548  recovered from the gap  546 . In alternative embodiments, the third channel  585  can recover at least approximately 50, 60, 70, 80, or 90 percent of the immersion fluid  548  recovered from the gap  546 . With this design, the fourth channel  587  can be used to capture the immersion fluid  548  not captured by the third channel  585 . 
     Additionally, in one embodiment, the environmental system  526  includes a pressure controller  591  that can be used to control the pressure in the gap  546 . In one embodiment, the pressure controller  591  can cause the pressure in the gap  546  to be approximately equal to the pressure outside of the gap  546 . For example, in one embodiment, the second channel  583  defines the pressure controller  591 . In this embodiment, the second channel  583  is open to the atmospheric pressure and is positioned inside the periphery of third channel  585 . With this design, the negative pressure (vacuum or partial vacuum) in the third channel  585  will not strongly influence the pressure between the optical assembly  516  and the wafer  30 . 
     Alternatively, for example, a control pressure source  593  can deliver a control fluid  595  (illustrated as triangles) to the second channel  583  that is released into the gap  546 . In one embodiment, the control fluid  595  can be a gas that is not easily absorbed by the immersion fluid  548 . For example, if the immersion fluid  548  is water, the control fluid  595  can be water. If the immersion fluid  548  does not absorb the control fluid  595  or otherwise react to it, the chances of bubble formation on the surface of the wafer  30  can be reduced. 
     In yet another embodiment, the environmental system  526  can include a device for creating a fluid bearing (not shown) between the containment frame  564  and the wafer  30  and/or the device stage  542 . For example, the containment frame  564  can include one or more bearing outlets (not shown) that are in fluid communication with a bearing fluid source (not shown) of a bearing fluid (not shown). In this embodiment, the bearing fluid source provides pressurized fluid to the bearing outlet to create the aerostatic bearing. The fluid bearings can support all or a portion of the weight of the containment frame  564 . 
     It should be noted that in each embodiment, additional transport regions can be added as necessary. 
     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 then inspected in step  606 . 
       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. 
     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. 
     Multiple circuit patterns are formed by repetition of these preprocessing and post-processing steps. 
     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 embodiments of the invention. No limitations are intended to the details of construction or design herein shown.

Technology Classification (CPC): 6