Source: https://patents.google.com/patent/US7948604B2/en
Timestamp: 2019-04-19 09:35:27+00:00

Document:
This application is a Continuation Application of International Application No. PCT/JP03/015407 which was filed on Dec. 2, 2003 claiming the conventional priority of Japanese patent Application No. 2002-357961 filed on Dec. 10, 2002, No. 2003-002820 filed on Jan. 9, 2003, and No. 2003-049367 filed on Feb. 26, 2003.
Semiconductor devices and liquid crystal display devices are produced by the so-called photolithography technique in which a pattern formed on a mask is transferred onto a photosensitive substrate. The exposure apparatus, which is used in the photolithography step, includes a mask stage for supporting the mask and a substrate stage for supporting the substrate. The pattern on the mask is transferred onto the substrate via a projection optical system while successively moving the mask stage and the substrate stage. In recent years, it is demanded to realize the higher resolution of the projection optical system in order to respond to the further advance of the higher integration of the device pattern. As the exposure wavelength to be used is shorter, the resolution of the projection optical system becomes higher. As the numerical aperture of the projection optical system is larger, the resolution of the projection optical system becomes higher. Therefore, the exposure wavelength, which is used for the exposure apparatus, is shortened year by year, and the numerical aperture of the projection optical system is increased as well. The exposure wavelength, which is dominantly used at present, is 248 nm of the KrF excimer laser. However, the exposure wavelength of 193 nm of the ArF excimer laser, which is shorter than the above, is also practically used in some situations. When the exposure is performed, the depth of focus (DOF) is also important in the same manner as the resolution. The resolution R and the depth of focus δ are represented by the following expressions respectively.
In the exposure apparatus of the present invention, it is preferable that the bubble-suppressing unit includes a degassing unit which removes any gas from the liquid. It is preferable that the degassing unit includes a heating unit which heats the liquid. The heating unit may set a temperature T of the liquid to be 30° C.<T≦100° C. Further, the degassing unit may include a pressure-reducing unit which reduces a pressure in a unit in which the liquid is retained. The pressure-reducing unit may set the pressure depending on a temperature of the liquid. Further, it is preferable that the degassing unit determines a degassing level so that the bubble is not generated by any change in temperature of at least a part of the liquid disposed between the projection optical system and the substrate. It is also preferable that the degassing unit determines a degassing level so that the bubble is not generated by any change in pressure exerted on the liquid between the projection optical system and the substrate.
The embodiment of the present invention will now be explained as exemplified by a case of the use of the scanning type exposure apparatus (so-called scanning stepper) as the exposure apparatus EX in which the substrate P is exposed with the pattern formed on the mask M while synchronously moving the mask M and the substrate P in mutually different directions (opposite directions) in the scanning directions. In the following explanation, the Z axis direction is the direction which is coincident with the optical axis AX of the projection optical system PL, the X axis direction is the synchronous movement direction (scanning direction) for the mask M and the substrate P in the plane perpendicular to the Z axis direction, and the Y axis direction is the direction (non-scanning direction) perpendicular to the Z axis direction and the Y axis direction. The directions about the X axis, the Y axis, and the Z axis are designated as θX, θY, and θZ directions respectively. The term “substrate” referred to herein includes those obtained by applying a resist on a semiconductor wafer, and the term “mask” includes a reticle formed with a device pattern to be subjected to the reduction projection onto the substrate.
The mask stage MST supports the mask M. The mask stage MST is two-dimensionally movable in the plane perpendicular to the optical axis AX of the projection optical system PL, i.e., in the XY plane, and it is finely rotatable in the δZ direction. The mask stage MST is driven by a mask stage-driving unit MSTD such as a linear motor. The mask stage-driving unit MSTD is controlled by the control unit CONT. The position in the two-dimensional direction and the angle of rotation of the mask M on the mask stage MST are measured in real-time by a laser interferometer. The result of the measurement is outputted to the control unit CONT. The control unit CONT drives the mask stage-driving unit MSTD on the basis of the result of the measurement obtained by the laser interferometer to thereby position the mask M supported on the mask stage MST.
The projection optical system PL projects the pattern on the mask M onto the substrate P at a predetermined projection magnification β to perform the exposure. The projection optical system PL includes a plurality of optical elements (lenses). The optical elements are supported by a barrel PK as a metal member. In this embodiment, the projection optical system PL is a reduction system having the projection magnification β which is, for example, ¼ or ⅕. The projection optical system PL may be any one of the 1× magnification system and the magnifying system. The optical element (lens) 60 is exposed from the barrel PK on the side of the tip (on the side of the substrate P) of the projection optical system PL of this embodiment. The optical element 60 is provided detachably (exchangeably) with respect to the barrel PK.
The substrate stage PST supports the substrate P. The substrate stage PST includes a Z stage 51 which holds the substrate P by the aid of a substrate holder, an XY stage 52 which supports the Z stage 51, and a base 53 which supports the XY stage 52. The substrate stage PST is driven by a substrate stage-driving unit PSTD such as a linear motor. The substrate stage-driving unit PSTD is controlled by the control unit CONT. When the Z stage 51 is driven, the substrate P, which is held on the Z stage 51, is subjected to the control of the position (focus position) in the Z axis direction and the positions in the θX and θY directions. When the XY stage 52 is driven, the substrate P is subjected to the control of the position in the XY directions (position in the directions substantially parallel to the image plane of the projection optical system PL). That is, the Z stage 51 controls the focus position and the angle of inclination of the substrate P so that the surface of the substrate P is adjusted to match the image plane of the projection optical system PL in the auto-focus manner and the auto-leveling manner. The XY stage 52 positions the substrate P in the X axis direction and the Y axis direction. It goes without saying that the Z stage and the XY stage may be provided as an integrated body.
FIG. 2 shows a partial magnified view of FIG. 1 illustrating, for example, the lower portion of the projection optical system PL of the exposure apparatus EX, the liquid supply unit 1, and the liquid recovery unit 2. In FIG. 2, the lens 60, which is disposed at the lowest end of the projection optical system PL has an end portion 60A which is formed so that the end portion 60A has a rectangular shape which is long in the Y axis direction (non-scanning direction) and which has necessary portion in the scanning direction. During the scanning exposure, a pattern image of a part of the mask M is projected onto the rectangular projection area disposed just under the end portion 60A. The mask M is moved at the velocity V in the −X direction (or in the +X direction) with respect to the projection optical system PL, in synchronization with which the substrate P is moved at the velocity β·V (β is the projection magnification) in the +X direction (or in the −X direction) by the aid of the XY stage 52. After the completion of the exposure for one shot area, the next shot area is moved to the scanning start position in accordance with the stepping of the substrate P. The exposure process is successively performed thereafter for each of the shot areas in accordance with the step-and-scan system. This embodiment is designed so that the liquid 50 is allowed to flow in the same direction as the movement direction of the substrate P in parallel to the movement direction of the substrate P.
FIG. 3 shows the positional relationship among the end portion 60A of the lens 60 of the projection optical system PL, the supply nozzles 4 (4A to 4C) for supplying the liquid 50 in the X axis direction, and the recovery nozzles 5 (5A, 5B) for recovering the liquid 50. In FIG. 3, the end portion 60A of the lens 60 has a rectangular shape which is long in the Y axis direction. The three supply nozzles 4A to 4C are arranged on the side in the +X direction, and the two recovery nozzles 5A, 5B are arranged on the side in the −X direction so that the end portion 60A of the lens 60 of the projection optical system PL is interposed therebetween in the X axis direction. The supply nozzles 4A to 4C are connected to the liquid supply unit 1 through the supply tube 3, and the recovery nozzles 5A, 5B are connected to the liquid recovery unit 2 through the recovery tube 4. Further, the supply nozzles 8A to 8C and the recovery nozzles 9A, 9B are arranged at positions obtained by rotating, by substantially 180°, the positions of the supply nozzles 4A to 4C and the recovery nozzles 5A, 5B about the center of the end portion 60A. The supply nozzles 4A to 4C and the recovery nozzles 9A, 9B are alternately arranged in the Y axis direction. The supply nozzles 8A to 8C and the recovery nozzles 5A, 5B are alternately arranged in the Y axis direction. The supply nozzles 8A to 8C are connected to the liquid supply unit 1 through the supply tube 10. The recovery nozzles 9A, 9B are connected to the liquid recovery unit 2 through the recovery tube 11. The liquid is supplied from the nozzles so that no gas portion is generated between the projection optical system PL and the substrate P.
The liquid supply unit 1 includes a filter 20 which removes any foreign matter or the like from the liquid 50 recovered by the liquid recovery unit 2, for example, by filtering the liquid 50 recovered by the liquid recovery unit 2 in order to avoid any pollution of the substrate P and the projection optical system PL and/or avoid any deterioration of the pattern image projected onto the substrate P, the heating unit 21 which heats the liquid 50 having passed through the filter 20 to a predetermined temperature (for example, 90° C.), and a temperature-adjusting unit 22 which adjusts the temperature of the liquid 50 having been heated by the heating unit 21 to a desired temperature. Although not shown in FIG. 4, the liquid supply unit 1 includes a reservoir such as a tank capable of retaining a predetermined amount of the liquid 50. In this embodiment, the temperature-adjusting unit 22, which is provided for the liquid supply unit 1, sets the temperature of the liquid 50 to be supplied to the space 56 to be approximately equivalent, for example, to the temperature (for example, 23° C.) in the chamber in which the exposure apparatus EX is accommodated. Supply tubes 3, 10 are connected to the temperature-adjusting unit 22. The liquid 50, which has been temperature-adjusted by the temperature-adjusting unit 22, is supplied to the space 56 through the supply tube 3 (10).
In this embodiment, the heating unit 21 sets the temperature of the liquid 50 to be not less than 30° C. and not more than 100° C. That is, the liquid 50 is heated at a temperature higher than the temperature (for example, 23° C. as the temperature in the chamber) set by the temperature-adjusting unit 22, and within a temperature range of not more than the boiling point of the liquid. The heating unit 21 degasses the liquid 50 by heating the liquid 50 within the temperature range as described above to suppress the generation of the bubble in the liquid 50 to be supplied to the space 56. In particular, the heating unit 21 can sufficiently degas the liquid 50 by heating the liquid 50 to the boiling point thereof.
When the scanning exposure is performed by moving the substrate P in the scanning direction (−X direction) indicated by an arrow Xa (see FIG. 3), the liquid 50 is supplied and recovered with the liquid supply unit 1 and the liquid recovery unit 2 by using the supply tube 3, the supply nozzles 4A to 4C, the recovery tube 4, and the recovery nozzles 5A, 5B. That is, when the substrate P is moved in the −X direction, then the liquid 50, for which the generation of the bubble is suppressed, is supplied to the space between the projection optical system PL and the substrate P from the liquid supply unit 1 through the supply tube 3 and the supply nozzles 4 (4A to 4C), and the liquid 50 is recovered to the liquid recovery unit 2 through the recovery nozzles 5 (5A, 5B) and the recovery tube 6. The liquid 50 flows in the −X direction so that the space between the lens 60 and the substrate P is filled therewith. On the other hand, when the scanning exposure is performed by moving the substrate P in the scanning direction (+X direction) indicated by an arrow Xb, then the liquid 50 is supplied and recovered with the liquid supply unit 1 and the liquid recovery unit 2 by using the supply tube 10, the supply nozzles 8A to 8C, the recovery tube 11, and the recovery nozzles 9A, 9B. That is, when the substrate P is moved in the +X direction, then the degassed liquid 50 is supplied from the liquid supply unit 1 to the space between the projection optical system PL and the substrate P through the supply tube 10 and the supply nozzles 8 (8A to 8C), and the liquid 50 is recovered to the liquid recovery unit 2 through the recovery nozzles 9 (9A, 9B) and the recovery tube 11. The liquid 50 flows in the +X direction so that the space between the lens 60 and the substrate P is filled therewith. As described above, the control unit CONT allows the liquid 50 to flow in the movement direction of the substrate P by using the liquid supply unit 1 and the liquid recovery unit 2. In this arrangement, for example, the liquid 50, which is supplied from the liquid supply unit 1 through the supply nozzles 4, flows so that the liquid 50 is attracted and introduced into the space 56 in accordance with the movement of the substrate P in the −X direction. Therefore, even when the supply energy of the liquid supply unit 1 is small, the liquid 50 can be supplied to the space 56 with ease. When the direction, in which the liquid 50 is allowed to flow, is switched depending on the scanning direction, then it is possible to fill the space between the substrate P and the tip surface 7 of the lens 60 with the liquid 50, and it is possible to obtain the high resolution and the wide depth of focus, even when the substrate P is subjected to the scanning in any one of the +X direction and the −X direction.
As shown in FIG. 5, the liquid supply unit 1 includes a filter 20 which removes any foreign matter from the liquid 50, for example, by filtering the liquid 50 recovered by the liquid recovery unit 2 in order to avoid any pollution of the substrate P and the projection optical system PL and/or avoid any deterioration of the pattern image projected onto the substrate P, the pressure-reducing unit 23 which degasses the liquid 50 by reducing the pressure of the liquid 50 from which the foreign matter has been removed by the filter 20, a temperature-adjusting unit 22 which adjusts the temperature of the liquid 50 having been subjected to the degassing treatment by the pressure-reducing unit 23 to a temperature approximately identical to the temperature in the chamber, and a pressurizing pump 15. The pressure-reducing unit 23 includes a reservoir which retains the liquid 50. The liquid 50 is degassed by reducing the pressure in the reservoir. The liquid 50 can be also degassed by reducing the pressure rather than by heating the liquid 50 as described above. The pressure-reducing unit 50 may include, for example, a reservoir which is capable of retaining a predetermined amount of the liquid 50, and a vacuum pump which is connected to the reservoir and which reduces the pressure of the gas that makes contact with the liquid 50 in the reservoir.
In this procedure, the pressure-reducing unit 23 sets the pressure depending on the temperature of the liquid 50. That is, a sufficient degassing effect is obtained by heating the liquid 50 to the boiling point. However, the boiling point of the liquid 50 depends on the pressure. Therefore, the liquid 50 can be degassed efficiently and satisfactorily by setting the pressure depending on the temperature of the liquid 50. For example, the pressure (boiling pressure), at which the boiling point of water as the liquid 50 is 100° C., is the atmospheric pressure (101,325 Pa). The boiling pressure, at which the boiling point is 90° C., is 70,121 Pa. Similarly, the boiling pressure is 47,377 Pa at a boiling point of 80° C., the boiling pressure is 12,345 Pa at a boiling point of 50° C., the boiling pressure is 4,244.9 Pa at a boiling point of 30° C., and the boiling pressure is 2,338.1 Pa at a boiling point of 20° C. Therefore, for example, when the temperature of the liquid 50 is set to 100° C. by the heating unit, the pressure-reducing unit 23 can degas the liquid 50 by boiling the liquid 50 at the atmospheric pressure without performing the pressure-reducing treatment. On the other hand, when the temperature of the liquid 50 is 90° C., the pressure-reducing unit 23 can degas the liquid 50 by boiling the liquid 50 by setting the pressure to be within a range from the atmospheric pressure to the boiling pressure (70,121 Pa) at the temperature of 90° C. Similarly, for example, when the temperature of the liquid 50 is 30 ° C., the pressure-reducing unit 23 can degas the liquid 50 by boiling the liquid 50 by setting the pressure to be within a range from the atmospheric pressure to the boiling pressure (4,244.9 Pa). As described above, the boiling point of the liquid 50 varies depending on the pressure. Therefore, the pressure-reducing unit 23 can degas the liquid 50 satisfactorily by setting the pressure depending on the temperature of the liquid 50.
The degassing level of the liquid 50 to be supplied to the space between the projection optical system PL and the substrate P, i.e., the concentration of dissolved gas of the liquid 50 may be determined depending on the condition of use of the liquid 50 (for example, the exposure condition). In the case of the liquid immersion exposure, the temperature of the liquid 50 disposed between the projection optical system PL and the substrate P is entirely or partially raised during the exposure due to the radiation of the exposure light beam EL or the heat of the substrate P heated by the radiation of the exposure light beam EL. The increase in the temperature of the liquid 50 differs, for example, depending on the intensity of the exposure light beam EL, which is about several degrees (1 to 3° C.). However, if the degassing level of the liquid 50 is low, there is such a possibility that the gas, which has been dissolved in the liquid 50, may be converted into the generated bubble due to the increase in the temperature of the liquid 50. Therefore, it is necessary to set the degassing level of the liquid 50 so that the bubble is not generated even when the increase in the temperature arises in the liquid 50 between the projection optical system PL and the substrate P. For example, as described above, when the liquid, which is temperature-controlled to about 23° C., is supplied to the space between the projection optical system PL and the substrate P, the degassing level may be set so that the bubble is not generated, for example, even when the temperature of the liquid is raised to 30° C., in view of the safety. Specifically, the degassing level of the liquid 50, i.e., of water may be set to be not more than the saturation amount of air dissolved in water at 30° C., i.e., 0.016 cm3/cm3 (not more than 13 ppm for N2 and not more than 7.8 ppm for O2 as expressed by the mass ratio). The expression “cm3/cm3” indicates the volume cm3 of air dissolved in 1 cm3 of water.
FIG. 6 shows an arrangement of the liquid supply unit 1. As shown in FIG. 6, the liquid supply unit 1 includes a filter 20 which removes any foreign matter or the like from the liquid 50 recovered by the liquid recovery unit 2, for example, by filtering the liquid 50 recovered by the liquid recovery unit 2 in order to avoid any pollution of the substrate P and the projection optical system PL and/or avoid any deterioration of the pattern image projected onto the substrate P, the heating unit 25 which heats the liquid 50 having passed through the filter 20 to a predetermined temperature, the membrane degassing unit 24 which removes the gas from the liquid 50 heated by the heating unit 25, a temperature-adjusting unit 22 which adjusts the temperature of the liquid 50 having been subjected to the degassing treatment by the membrane degassing unit 24 to be a desired temperature, and a pressurizing pump 15. The liquid 50, for which the concentration of dissolved gas has been lowered by the heating unit 25, is supplied to the membrane degassing unit 24 through the tube 12. The liquid 50, which has been degassed by the membrane degassing unit 24, is supplied to the temperature-adjusting unit 22 through the tube 14. The membrane degassing unit 24 is connected to the discharge tube 13 to discharge the gas removed (degassed) from the liquid 50. The temperature-adjusting unit 22 sets the temperature of the liquid 50 to be supplied to the space 56 to be approximately equivalent, for example, to the temperature (for example, 23° C.) in the chamber in which the exposure apparatus EX is accommodated. Supply tubes 3, 10 are connected to the temperature-adjusting unit 22. The liquid 50, which has been temperature-adjusted by the temperature-adjusting unit 22, is supplied to the space 56 through the supply tube 3 (10) by the pressurizing pump 15. The operation of the membrane degassing unit 24 is also controlled by the control unit CONT.
FIG. 7 shows a sectional view illustrating a schematic arrangement of the membrane degassing unit 24. A cylindrical hollow fiber bundle 72 is accommodated in a housing 71 while leaving a predetermined space 73. The hollow fiber bundle 72 includes a plurality of straw-shaped hollow fiber membranes 74 which are bundled in parallel. Each of the hollow fiber membranes 74 is formed of a material (for example, poly-4-methylpentene-1) which is highly hydrophobic and which is excellent in gas permeability. Vacuum cap members 75 a, 75 b are fixed at the both ends of the housing 71. Tightly sealed spaces 76 a, 76 b are formed at the outside of the housing 71 at the both ends. Degassing ports 77 a, 77 b, which are connected to an unillustrated vacuum pump, are provided for the vacuum cap members 75 a, 75 b. Sealing sections 78 a, 78 b are formed at the both ends of the housing 71 so that only the both ends of the hollow fiber bundle 72 are connected to the tightly sealed spaces 76 a, 76 b, respectively. The vacuum pump, which is connected to the degassing ports 77 a, 77 b, can be used to provide the pressure-reduced state for the inside of each of the hollow fiber membranes 74. A tube 79, which is connected to the tube 12, is arranged in the hollow fiber bundle 72. The tube 79 is provided with a plurality of liquid supply holes 80. The liquid 50 is supplied from the liquid supply holes 80 to a space 81 which is surrounded by the sealing sections 78 a, 78 b and the hollow fiber bundle 72. When the liquid 50 is continuously supplied from the liquid supply holes 80 to the space 81, then the liquid 50 flows toward the outside so that the liquid 50 traverses the layers of the hollow fiber membranes 74 bundled in parallel, and the liquid 50 makes contact with the outer surfaces of the hollow fiber membranes 74. As described above, each of the hollow fiber membranes 74 is formed of the material which is highly hydrophobic and which is excellent in gas permeability. Therefore, the liquid 50 does not enter the inside of the hollow fiber membrane 74, and the liquid 50 passes through interstices of the respective hollow fiber membranes 74 to move to the space 73 disposed outside the hollow fiber bundle 72. On the other hand, the gas (molecule) dissolved in the liquid 50 is moved (absorbed) to the inside of each of the hollow fiber membranes 74, because the inside of each of the hollow fiber membranes 74 is in a pressure-reducer state (about 20 Torr). The gas component, which is removed (degassed) from the liquid 50 during the traverse across the layers of the hollow fiber membranes 74 as described above, passes through the both ends of the hollow fiber bundle 72, and the gas component is discharged from the degassing ports 77 a, 77 b via the tightly sealed spaces 76 a, 76 b as shown by arrows 83. The liquid 50, which has been subjected to the degassing treatment, is supplied to the temperature-adjusting unit 22 through the tube 14 from a liquid outlet 82 provided for the housing 51.
As explained above, the liquid supply unit 1, which supplies the liquid 50 to the space between the projection optical system PL and the substrate P, is provided with the membrane degassing unit 24 which removes (degasses) the gas from the liquid 50. Accordingly, the liquid 50 can be supplied to the space between the projection optical system PL and the substrate P after the liquid 50 is sufficiently degassed. Therefore, it is possible to suppress the generation of the bubble in the liquid 50 which fills the space between the projection optical system PL and the substrate P during the exposure process. Even if the bubble is generated by any cause, for example, in the flow passage between the membrane degassing unit 24 and the space 56, on the tip surface 7 of the projection optical system PL, or on the surface of the substrate P, then the sufficiently degassed liquid 50 flows through the flow passage and the space 56, and thus the liquid 50 can absorb and remove the bubble existing in the flow passage. As described above, the exposure process can be performed in the state in which no bubble is present in the liquid 50 on the optical path for the exposure light beam EL. Therefore, it is possible to avoid the deterioration of the pattern image which would be otherwise caused by the bubble, and it is possible to produce a device having a high pattern accuracy.
In the respective embodiments described above, the shape of the nozzle is not specifically limited. For example, two pairs of the nozzles may be used to supply or recover the liquid 50 for the long side of the end portion 60A. In this arrangement, the supply nozzles and the recovery nozzles may be arranged while being aligned vertically in order that the liquid 50 can be supplied and recovered in any one of the directions of the +X direction and the −X direction.
In the embodiments described above, the exposure apparatus is adopted, in which the space between the projection optical system PL and the substrate P is locally filled with the liquid. However, the present invention is also applicable to a liquid immersion exposure apparatus in which a stage holding a substrate as an exposure objective is moved in a liquid bath, and a liquid immersion exposure apparatus in which a liquid pool having a predetermined depth is formed on a stage and a substrate is held therein. The structure and the exposure operation of the liquid immersion exposure apparatus in which the stage holding the substrate as the exposure objective is moved in the liquid bath are described in detail, for example, in Japanese Patent Application Laid-open No. 6-124873, content of which is incorporated herein by reference within a range of permission of the domestic laws and ordinances of the state designated or selected in this international application. The structure and the exposure operation of the liquid immersion exposure apparatus in which the liquid pool having the predetermined depth is formed on the stage and the substrate is held therein are described in detail, for example, in Japanese Patent Application Laid-open No. 10-303114 and U.S. Pat. No. 5,825,043, contents of which are incorporated herein by reference respectively within a range of permission of the domestic laws and ordinances of the state designated or selected in this international application.
The reaction force, which is generated in accordance with the movement of the substrate stage PST, may be mechanically released to the floor (ground) by using a frame member so that the reaction force is not transmitted to the projection optical system PL. The method for handling the reaction force is disclosed in detail, for example, in Japanese Patent Application Laid-open No. 8-166475 (corresponding to U.S. Pat. No. 5,528,118), contents of which are incorporated herein by reference within a range of permission of the domestic laws and ordinances of the state designated or selected in this international application.
The reaction force, which is generated in accordance with the movement of the mask stage MST, may be mechanically released to the floor (ground) by using a frame member so that the reaction force is not transmitted to the projection optical system PL. The method for handling the reaction force is disclosed in detail, for example, in Japanese Patent Application Laid-open No. 8-330224 (corresponding to U.S. Pat. No. 5,874,820), contents of which are incorporated herein by reference within a range of permission of the domestic laws and ordinances of the state designated or selected in this international application.
a gas-removing unit which removes a gas component dissolved in the liquid which is to be supplied to the space between the projection optical system and the substrate so that bubbles are not generated in the space when at least one of temperature of the liquid and pressure exerted on the liquid in the space is changed during exposure.
2. The exposure apparatus according to claim 1, wherein the gas-removing unit removes the gas component from the liquid so that an air concentration in the liquid is not more than 0.016 cm3/cm3.
3. The exposure apparatus according to claim 1, wherein the gas-removing unit is at least one of a heating unit, a pressure-reducing unit, and a degassing membrane.
4. The exposure apparatus according to claim 1, wherein the liquid supply unit includes a plurality of supply nozzles which supply the liquid to the space between the projection optical system and the substrate, and a plurality of recovery nozzles which recover the liquid supplied to the space between the projection optical system and the substrate.
5. The exposure apparatus according to claim 4, wherein the exposure apparatus further comprises a stage which is movable while placing the substrate thereon, the exposure is performed during a period in which the stage moves the substrate with respect to the image projected from the projection optical system, and the supply nozzles jet the liquid in a direction of movement of the substrate.
6. The exposure apparatus according to claim 4, wherein the supply nozzles and the recovery nozzles are alternately arranged.
7. The exposure apparatus according to claim 6, wherein combinations of the supply nozzles and the recovery nozzles arranged alternately are opposed to one another with a projection area of the projection optical system intervening therebetween.
8. The exposure apparatus according to claim 1, further comprising a temperature-adjusting unit which adjusts a temperature of the liquid supplied from the liquid supply unit.
9. The exposure apparatus according to claim 8, wherein the temperature-adjusting unit adjusts the temperature of the liquid so that the temperature of the liquid is a temperature in the exposure apparatus.
10. The exposure apparatus according to claim 9, wherein a temperature of the substrate is controlled by supplying the temperature-adjusted liquid to the space between the projection optical system and the substrate.
wherein the bubble-suppressing unit includes a degassing unit which removes gas from the liquid over a degassing level so that the bubble is not generated in the space by change in at least one of temperature of the liquid and pressure exerted on the liquid between the projection optical system and the substrate during exposure.
12. The exposure apparatus according to claim 11, wherein the degassing unit includes a heating unit which heats the liquid.
13. The exposure apparatus according to claim 12, wherein the heating unit sets a temperature T of the liquid to be 30° C.<T≦100° C.
14. The exposure apparatus according to claim 11, wherein the degassing unit includes a pressure-reducing unit which reduces a pressure in a unit in which the liquid is retained.
15. The exposure apparatus according to claim 14, wherein the pressure-reducing unit sets the pressure depending on a temperature of the liquid.
16. The exposure apparatus according to claim 11, wherein the degassing unit determines the degassing level so that the bubble is not generated by any change in the temperature of at least a part of the liquid disposed between the projection optical system and the substrate.
17. The exposure apparatus according to claim 11, wherein the degassing unit determines the degassing level so that the bubble is not generated by any change in the pressure exerted on the liquid between the projection optical system and the substrate.
18. The exposure apparatus according to claim 11, wherein the degassing unit is a membrane degassing unit.
19. The exposure apparatus according to claim 18, wherein the membrane degassing unit includes a hollow fiber member.
20. The exposure apparatus according to claim 19, wherein the hollow fiber member is gas-permeable and liquid-impermeable.
21. The exposure apparatus according to claim 18, further comprising a heating unit which heats the liquid which is to be supplied to the membrane degassing unit to decrease a concentration of dissolved gas in the liquid which is to be supplied to the membrane degassing unit.
22. The exposure apparatus according to claim 11, wherein the liquid, for which the generation of the bubble has been suppressed by the bubble-suppressing unit, is supplied to the space between the projection optical system and the substrate without making a contact with gas.
23. The exposure apparatus according to claim 11, wherein the liquid supply unit includes a filter unit which filters the liquid which is to be supplied to the space between the projection optical system and the substrate.
24. The exposure apparatus according to claim 23, wherein the liquid supply unit further includes a temperature-adjusting unit which adjusts a temperature of the liquid having been degassed by the degassing unit.
25. The exposure apparatus according to claim 11, wherein the liquid supply unit further includes a temperature-adjusting unit which adjusts a temperature of the liquid having been degassed by the degassing unit.
processing the exposed substrate to produce the device.
28. The exposure apparatus according to claim 1, wherein the gas-removing unit removes the gas component dissolved in the liquid.
29. The exposure apparatus according to claim 28, wherein the gas-removing unit includes a degassing system.
30. The exposure apparatus according to claim 29, further comprising a temperature-adjusting unit which adjusts the temperature of the liquid degassed by the degassing system.
31. The exposure apparatus according to claim 29, further comprising a filter unit which filters the liquid before degassing the liquid by the degassing system.
32. The exposure apparatus according to claim 28, further comprising a liquid recovery unit which recovers the liquid on the substrate and returns the recovered liquid to the liquid supply unit.
33. The exposure apparatus according to claim 1, further comprising a liquid recovery unit which recovers the liquid on the substrate and returns the recovered liquid to the liquid supply unit.
34. The exposure apparatus according to claim 11, wherein the bubble-suppressing unit removes the gas component dissolved in the liquid.
35. The exposure apparatus according to claim 11, further comprising a filter unit which filters the liquid before degassing the liquid by the degassing unit.
36. The exposure apparatus according to claim 34, further comprising a liquid recovery unit which recovers the liquid on the substrate and returns the recovered liquid to the liquid supply unit.
37. The exposure apparatus according to claim 11, further comprising a liquid recovery unit which recovers the liquid on the substrate and returns the recovered liquid to the liquid supply unit.
wherein the degassed liquid is produced by removing the gas component so that bubbles are not generated in the immersion area when at least one of temperature of the liquid and pressure exerted on the liquid in the space is changed during exposure.
adjusting the temperature of the degassed liquid.
filtering the liquid before removing the gas component from the liquid.
41. The exposure method according to claim 38, wherein the gas component is removed by using a membrane.
a measuring member provided at the stage, wherein the liquid from which the gas component is removed is supplied to a space between the projection optical system and the measuring member.
a sensor provided at the stage, wherein the liquid from which the gas component is removed is supplied to a space between the projection optical system and the sensor.
45. The exposure apparatus according to claim 28, wherein the gas component includes oxygen.
46. The exposure apparatus according to claim 28, wherein the gas component includes nitrogen.
47. The exposure apparatus according to claim 29, wherein the degassing system includes a membrane degassing unit.
48. The exposure apparatus according to claim 47, wherein the membrane degassing unit includes a gas-permeable and liquid-impermeable member.
a measuring member provided at the stage, wherein the liquid in which generation of bubbles has been suppressed is supplied to a space between the projection optical system and the measuring member.
a sensor provided at the stage, wherein the liquid in which generation of bubbles has been suppressed is supplied to a space between the projection optical system and the sensor.
51. The exposure apparatus according to claim 34, wherein the gas component includes oxygen.
52. The exposure apparatus according to claim 34, wherein the gas component includes nitrogen.
53. The exposure apparatus according to claim 34, wherein the degassing unit includes a membrane degassing unit.
54. The exposure apparatus according to claim 53, wherein the membrane degassing unit includes a gas-permeable and liquid-impermeable member.
wherein the bubble-suppressing unit includes a degassing unit which removes gas from the liquid over a degassing level so that the bubble is not generated in the space during exposure, the degassing unit includes a pressure-reducing unit which reduces a pressure in a unit in which the liquid is retained, and the pressure-reducing unit sets the pressure depending on a temperature of the liquid.
a heating unit which heats the liquid which is to be supplied to the membrane degassing unit to decrease a concentration of dissolved gas in the liquid which is to be supplied to the membrane degassing unit.
NL2003820A (en) * 2008-12-22 2010-06-23 Asml Netherlands Bv Fluid handling structure, table, lithographic apparatus, immersion lithographic apparatus, and device manufacturing methods.
"Gas-dissolving and degassing module LIQUI-CEL (trade name)" by Dainippon Ink and Chemicals, Incorporated, Apr. 24, 2001, [on line], [retrieved on Apr. 24, 2006]. Retrieved from the internet .
"Gas-dissolving and degassing module LIQUI-CEL (trade name)" by Dainippon Ink and Chemicals, Incorporated, Apr. 24, 2001, [on line], [retrieved on Apr. 24, 2006]. Retrieved from the internet <URL:http://www.celgard.co.jp/CKKFiles/products.html>.
"Hollow Fiber Membrane Degassing Module: SEPAREL (trade name)", Dainippon Ink and Chemicals, Incorporated, 2001 [on line], [retrieved on May 31, 2006]. Retrieved from the internet .
"Hollow Fiber Membrane Degassing Module: SEPAREL (trade name)", Dainippon Ink and Chemicals, Incorporated, 2001 [on line], [retrieved on May 31, 2006]. Retrieved from the internet <URL:http://www.dic.co.jp/eng/products/memb/index.html>.
"SEPAREL (trade name) EF Series", Dainippon Ink and Chemicals, Incorporated, 2001, [on line], [retrieved on Apr. 24, 2006]. Retrieved from the internet .
"SEPAREL (trade name) EF Series", Dainippon Ink and Chemicals, Incorporated, 2001, [on line], [retrieved on Apr. 24, 2006]. Retrieved from the internet <URL:http://www.dic.co.jp/products/memb/ef.html>.
Apr. 23, 2010 Office Action in Japanese Application No. 2003-410471, with translation.
Apr. 30, 2008 Office Action in U.S. Appl. No. 11/399,595.
Apr. 5, 2007 Office Action in U.S. Appl. No. 11/399,595.
Dec. 15, 2009 Office Action in Japanese Application No. 2003-410471, with translation.
Dec. 31, 2007 Notice of Allowance in U.S. Appl. No. 11/399,595.
Emerging Lithographic Technologies V1, Proceedings of SPIE, vol. 4688 (2002), "Semiconductor Foundry, Lithography, and Partners", B.J. Lin, pp. 11-24.
Jan. 12, 2007 Office Action in Chinese Application No. 200380105396.6, with translation.
Jan. 28, 2010 Office Action in U.S. Appl. No. 11/399,595.
Mar. 20, 2009 Office Action in Chinese Application No. 2007101383468, with translation.
Mar. 31, 2010 Notice of Examination Opinion in Taiwan Application No. 092134802, with translation.
March 12, 2008 Supplementary European Search Report in European Application No. 03812697.5.
March 30, 2004 International Search Report in International Application No. PCT/JP03/15407, with translation.
May 12, 2009 Office Action in U.S. Appl. No. 11/399,595.
May 4, 2009 Danish Search and Examination Report in Singapore Application No. 200704276-5.
Nikon Corporation, 3rd 157 nm symposium, Sep. 4, 2002, "Nikon F2 Exposure Tool", Soichi Owa et al., 25 pages (slides 1-25).
Nikon Corporation, NGL Workshop, Jul. 10, 2003, :Potential performance and feasibility of immersion lithography, Soichi Owa et al., 33 pages, slides 1-33.
Oct. 10, 2008 Office Action in Chinese Application No. 2007101383468, with translation.
Oct. 31, 2008 Office Action in U.S. Appl. No. 11/399,595.
October 25, 2010 Office Action in U.S. Appl. No. 11/399,595.

References: Application No. 2002
 Application No. 2003
 Application No. 2003
 Application No. 200380105396
 Application No. 2007101383468
 Application No. 092134802
 Application No. 03812697
 Application No. 200704276
 Application No. 2007101383468