JP5446984B2 - Mirror temperature control device, optical system, and exposure device - Google Patents

Description

  The present invention relates to a mirror temperature control device that adjusts the temperature of a mirror that reflects light, an optical system that includes the mirror temperature control device, and an exposure apparatus that includes the mirror temperature control device.

  In recent years, along with miniaturization of semiconductor integrated circuits, a projection lithography technique using extreme ultraviolet light (hereinafter referred to as EUV (Extreme UltraViolet) light in this specification) as exposure light has been developed. This projection lithography technique is expected as a technique capable of obtaining a resolution of 32 nm or less.

  By the way, in an exposure apparatus that uses EUV light as exposure light (hereinafter abbreviated as EUV exposure apparatus), an optical material that transmits EUV light does not exist at the present time, so that a transmissive lens cannot be used. For this reason, the EUV exposure apparatus uses a multilayer mirror in which a multilayer reflective film that reflects EUV light is formed on a reflective surface. The multilayer mirror is a mirror that obtains a high reflectivity by laminating a large number of substances having a high refractive index and substances having a low refractive index in a used wavelength region on a substrate alternately.

  However, the reflectance of the multilayer mirror that reflects EUV light is about 70%. For this reason, about 30% of the energy of EUV light is absorbed by the multilayer mirror. The temperature of the multilayer mirror rises due to the absorbed energy.

  Therefore, the EUV exposure apparatus is provided with a mirror cooling mechanism that cools the multilayer mirror using radiant heat. This mirror cooling mechanism includes a radiation temperature control plate that is disposed opposite to the reflective surface (for example, the back surface) other than the reflective surface of the multilayer mirror with a space therebetween. The mirror cooling mechanism indirectly cools the multilayer mirror by exchanging heat between the radiation temperature control plate and the multilayer mirror by passing cooling water through the radiation temperature control plate.

Japanese Patent Laid-Open No. 2008-124079

  However, since the conventional mirror cooling mechanism cools the multilayer mirror using radiant heat, it takes a long time to adjust the multilayer mirror within a predetermined temperature range. Further, in the conventional mirror cooling mechanism, in order to discharge a large amount of heat from the multilayer mirror, it is necessary to greatly increase the temperature difference between the multilayer mirror and the radiation temperature control plate. For this reason, according to the conventional mirror cooling mechanism, when the thermal load of the multilayer mirror changes greatly, it is difficult to adjust the temperature of the multilayer mirror within a predetermined temperature range with good responsiveness.

  The present invention has been made in view of the above problems, and an object thereof is to provide a mirror temperature adjusting device, an optical system, and an exposure device that can adjust the temperature of a mirror with high responsiveness.

  In order to solve the above problems and achieve the object, a mirror temperature control device, an optical system, and an exposure device according to the present invention are arranged at a predetermined distance from a mirror that reflects light, and between the mirror. A temperature adjusting mechanism that adjusts the temperature of the intervening fluid; and a drive mechanism that moves the temperature adjusting mechanism in a direction close to or away from the mirror.

  According to the mirror temperature control device, the optical system, and the exposure device according to the present invention, the temperature of the mirror can be adjusted with high responsiveness.

FIG. 1 is a schematic side sectional view showing the overall configuration of an exposure apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the control system of the exposure apparatus shown in FIG. FIG. 3 is a plan view showing the configuration of the mirror temperature control apparatus according to the first embodiment of the present invention. 4 is a cross-sectional view taken along line AA of the mirror temperature control apparatus shown in FIG. FIG. 5 is a diagram for explaining the operation of the mirror temperature control apparatus when the thermal load on the mirror is increased. FIG. 6 is a diagram for explaining the operation of the mirror temperature control apparatus when the thermal load on the mirror is reduced. FIG. 7 is a diagram for explaining the operation of the mirror temperature control device when the mirror is thermally insulated. FIG. 8 is a plan view showing a configuration of a modified example of the mirror temperature control apparatus shown in FIG. FIG. 9 is a cross-sectional view taken along line AA of the mirror temperature control apparatus shown in FIG. FIG. 10 is a schematic diagram showing an illumination area of dipole illumination. FIG. 11 is a diagram illustrating a configuration of a modified example of the mirror temperature control apparatus illustrated in FIG. 9. FIG. 12 is a plan view showing a configuration of a mirror temperature control apparatus according to the second embodiment of the present invention. 13 is a cross-sectional view taken along line AA of the mirror temperature control apparatus shown in FIG. FIG. 14 is a diagram illustrating a configuration of a modified example of the mirror temperature control apparatus illustrated in FIG. 13.

  Hereinafter, an exposure apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[Configuration of exposure apparatus]
First, the overall configuration of an exposure apparatus that is an embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a schematic side sectional view showing the overall configuration of an exposure apparatus according to an embodiment of the present invention. As shown in FIG. 1, an exposure apparatus 1 according to an embodiment of the present invention includes a vacuum chamber 10, a laser plasma light source 20, an illumination optical system ILS, a reticle stage RST that holds a reticle R, and a projection optical system. PO and wafer stage WST are provided. The illumination optical system ILS and the projection optical system PO correspond to the first optical system and the second optical system according to the present invention, respectively. In this embodiment, since EUV light is used as exposure light, the illumination optical system ILS and the projection optical system PO are composed of a plurality of reflection optical members (mirrors), and the reticle R is also composed of a reflection type. A multilayer reflective film that reflects EUV light is formed on the reflective surface of these reflective optical members and the reflective surface of the reticle R. In the following, the normal direction of the bottom surface of the vacuum chamber 10 is defined as the Z direction, and the directions parallel to and perpendicular to the plane of FIG. 1 in the plane perpendicular to the Z direction are the X direction and the Y direction, respectively. Define.

  The vacuum chamber 10 includes an exhaust pipe 11a and an exhaust pipe 11b on the upper surface and the bottom surface, respectively. The exhaust pipe 11a and the exhaust pipe 11b are connected to a vacuum pump 12a and a vacuum pump 12b installed outside the vacuum chamber 10, respectively. The vacuum pump 12a and the vacuum pump 12b evacuate the vacuum chamber 10 through the exhaust pipe 11a and the exhaust pipe 11b, respectively. Therefore, by evacuating the inside of the vacuum chamber 10, it is possible to suppress the EUV light from being absorbed by the gas.

  The laser plasma light source 20 includes a laser light source 21, a condenser lens 22, a nozzle 23, and a condenser mirror 24. The laser light source 21 is installed outside the vacuum chamber 10. The laser light source 21 irradiates a condensing lens 22 disposed in the vacuum chamber 10 with laser light through a window portion 13 formed on the side surface of the vacuum chamber 10. The condensing lens 22 condenses the laser light emitted from the laser light source 21 onto a target gas such as xenon or krypton ejected from the nozzle 23.

  The target gas ejected from the nozzle 23 is turned into plasma by the laser light collected by the condenser lens 22 and emits EUV light. The target gas ejection position is positioned at the first focal position of the condensing mirror 24, which is an elliptical reflecting mirror. Therefore, the EUV light emitted from the target gas is condensed on the condensing region including the second focal position of the condensing mirror 24, and the EUV light that has passed through the condensing region reaches the illumination optical system ILS. The target gas that has finished emitting light is discharged through the exhaust pipe 11a and the exhaust pipe 11b.

  The illumination optical system ILS includes a concave mirror 31, a pair of fly-eye optical systems 32 and 33, an aperture stop AS, a curved mirror 34, a concave mirror 35, and blind plates 36a and 36b. The concave mirror 31, the pair of fly-eye optical systems 32 and 33, the curved mirror 34, and the concave mirror 35 are held by a lens barrel (not shown). The concave mirror 31 converts the EUV light EL that has passed through the condensing region including the second focal point of the condensing mirror 24 into a substantially parallel light beam and enters the pair of fly-eye optical systems 32 and 33. The pair of fly-eye optical systems 32 and 33 uniformize the illuminance distribution of the EUV light EL, and once collect the EUV light EL having the uniform illuminance distribution, guide it to the curved mirror 34.

  The aperture stop AS is disposed in the vicinity of the reflective surface of the fly-eye optical system 33. The aperture stop AS is switched to various aperture stops corresponding to normal illumination, annular illumination, dipole illumination, or the like according to control by a main controller (not shown). The curved mirror 34 causes the EUV light EL guided by the pair of fly-eye optical systems 32 and 33 to enter the concave mirror 35. The concave mirror 35 guides the EUV light EL guided by the curved mirror 34 to the blind plates 36a and 36b. The curved mirror 34 and the concave mirror 35 are respectively provided with a mirror temperature adjusting device 200 and a mirror temperature adjusting device 100 described later.

  The blind plate 36 a shields the end portion in the −X direction of the EUV light EL guided by the concave mirror 35. The EUV light EL partially shielded by the blind plate 36a illuminates the illumination area 37 on the pattern surface of the reticle R obliquely from below with a uniform illuminance distribution. The blind plate 36 b shields the end in the + X direction of the EUV light EL reflected by the illumination area 37. The EUV light EL partially shielded by the blind plate 36a is incident on the projection optical system PO.

  Reticle stage RST attracts and holds reticle R on the bottom surface thereof via electrostatic chuck RH. A partition 14 is provided on the upper surface of the reticle stage RST so as to cover the reticle stage RST on the vacuum chamber 1 side. The partition 14 is maintained at an atmospheric pressure between the atmospheric pressure and the atmospheric pressure in the vacuum chamber 1 by a vacuum pump (not shown).

  The projection optical system PO is configured by holding six mirrors M1 to M6 by a subchamber (lens barrel) (not shown). The projection optical system PO is a non-telecentric and telecentric reflection system on the reticle R side and the wafer W side, respectively, and the projection magnification is a reduction magnification such as 1/4. The mirrors M1 to M4 and M6 are concave mirrors, and the mirror M5 is a convex mirror.

  The mirror M1 reflects the EUV light EL reflected by the illumination area 37 of the reticle R in the + Z direction. The mirror M2 reflects the EUV light EL reflected by the mirror M1 in the -Z direction. The mirror M3 reflects the EUV light EL reflected by the mirror M2 in the + Z direction. The mirror M4 reflects the EUV light EL reflected by the mirror M3 in the −Z direction. The mirror M5 reflects the EUV light EL reflected by the mirror M4 in the + Z direction. The mirror M6 irradiates the exposure region 40 on the wafer W with the EUV light EL reflected by the mirror M5, thereby forming a reduced image of a part of the pattern of the reticle R in the exposure region 40.

  Wafer stage WST is arranged on a guide surface arranged along the XY plane, and holds wafer W on its upper surface via an electrostatic chuck (not shown). Wafer stage WST as a whole is partitioned in vacuum chamber 10 by partition 15 having an opening through which EUV light EL passes. The space in the partition 15 is evacuated by a vacuum pump (not shown). By providing the partition 15, it is possible to suppress the gas generated from the resist on the wafer W from adversely affecting the mirrors M1 to M6 of the projection optical system PO.

  In the vicinity of wafer W on wafer stage WST, an aerial image measurement system 41 that detects an image of the alignment mark of reticle R is installed. A main controller (not shown) calculates the optical characteristics of the projection optical system PO based on the detection result of the aerial image measurement system 41, and the optical characteristics of the projection optical system PO are maintained within a predetermined allowable range based on the calculation result. Thus, the optical characteristics of the projection optical system PO are controlled.

[Control system configuration]
Next, the configuration of the control system of the exposure apparatus 1 will be described with reference to FIG.

  FIG. 2 is a block diagram showing the configuration of the control system of the exposure apparatus 1 shown in FIG. As shown in FIG. 2, the exposure apparatus 1 includes a reticle interferometer 51, a reticle autofocus system 52, a wafer interferometer 53, a temperature sensor 54, and a main controller 55 as a control system. Reticle interferometer 51 detects position information of reticle stage RST in the XY plane, and inputs an electric signal indicating the detected position information to main controller 55.

  The reticle autofocus system 52 detects position information in the Z direction of the pattern surface of the reticle R, and inputs an electric signal indicating the detected position information to the main controller 55. Wafer interferometer 53 detects the position information of wafer W, and inputs an electrical signal indicating the detected position information to main controller 55. The temperature sensor 54 detects the temperature of a mirror whose temperature is to be adjusted (the curved mirror 34 and the concave mirror 35 in this embodiment) or a temperature adjusting member described later, and sends an electric signal indicating the detection result to the main controller 55. input.

  The main control device 55 is realized by an arithmetic processing device such as a microcomputer. The main controller 55 controls the overall operation of the exposure apparatus 1. Specifically, main controller 55 drives reticle stage drive system 61 based on the electrical signal input from reticle interferometer 51. The reticle stage drive system 61 moves the reticle stage RST with a predetermined stroke in the Y direction along a guide surface parallel to the XY plane, and in the X direction and θz direction (rotation direction around the Z axis) as necessary. Also, move the reticle stage RST by a small amount. Further, main controller 55 drives reticle stage drive system 61 based on the electric signal input from reticle autofocus system 52. The reticle stage drive system 61 controls the position of the reticle R in the Z direction within an allowable range by moving the reticle stage RST.

  Main controller 55 drives wafer stage drive system 62 based on the electrical signal from wafer interferometer 53. Wafer stage drive system 62 moves wafer stage WST with a predetermined stroke in the X direction and the Y direction, and also moves wafer stage WST in the θz direction or the like as necessary. The main controller 55 controls the operation of the cooling mechanism drive system 63 and the refrigerant supply device 64 according to the mirror temperature detected by the temperature sensor 54, thereby controlling the mirror temperature within a predetermined temperature range. The operations of the cooling mechanism drive system 63 and the refrigerant supply device 64 will be described later.

[Exposure operation]
When performing exposure using the exposure apparatus 1, first, the wafer W is placed on the wafer stage WST. When exposing one shot area on the wafer W, the EUV light EL illuminates the illumination area 37 of the reticle R by the illumination optical system ILS, and the reticle R and the wafer W are predetermined according to the reduction magnification of the projection optical system PO. Is moved in synchronism with the projection optical system PO in the Y direction at the speed ratio. As a result, the pattern on the reticle R is exposed to one shot area on the wafer W. Next, after wafer stage WST is driven to move wafer W stepwise, the pattern of reticle R is exposed to the next shot area on wafer W. In this manner, the pattern image of the reticle R is sequentially exposed to a plurality of shot areas on the wafer W by the step-and-scan method.

[Configuration of mirror temperature control device]
Next, the configuration of a mirror temperature adjusting device that adjusts the temperatures of the curved mirror 34 and the concave mirror 35 constituting the exposure apparatus 1 will be described. In the present embodiment, the temperatures of the curved mirror 34 and the concave mirror 35 are adjusted. However, the target mirrors for adjusting the temperature are not limited to the curved mirror 34 and the concave mirror 35. In other words, the mirror temperature control device can be applied to all mirrors that may generate heat by absorbing the EUV light EL, such as the mirrors M1 to M6 constituting the projection optical system PO.

[First Embodiment]
First, with reference to FIG. 3 and FIG. 4, the configuration of the mirror temperature control apparatus according to the first embodiment of the present invention will be described. Note that the mirror temperature adjustment device of the present embodiment is for adjusting the temperature of the concave mirror 35 shown in FIG. 1, and is applied to a mirror having a reflective surface that reflects EUV light on the upper surface (+ Z direction) side. be able to.

  FIG. 3 is a plan view showing the configuration of the mirror temperature control apparatus according to the first embodiment of the present invention. 4 is a cross-sectional view taken along line AA of the mirror temperature control apparatus shown in FIG. As shown in FIGS. 3 and 4, the mirror temperature adjusting device 100 according to the first embodiment of the present invention is disposed on the back surface 35 c side opposite to the reflecting surface 35 b of the concave mirror 35, and the temperature adjusting member 101. A refrigerant pipe 102, a cooling jacket 103, a Peltier element 104, and a drive mechanism 105. The concave mirror 35 is held by the lens barrel via the holding portion 35a.

  The temperature adjustment member 101 is made of a metal material such as aluminum, aluminum alloy, molybdenum, stainless steel, or copper, and is held by a drive mechanism 105 described later.

  The temperature adjustment member 101 is a container having a recess 101a. The recess 101a is formed in a rectangular shape in plan view. A liquid metal 106 that maintains a liquid state at room temperature (for example, room temperature of 20 to 30 ° C.) is held in the recess 101a. Examples of the liquid metal 106 that maintains a liquid state at room temperature include mercury, a gallium-indium alloy, or an alloy of two or more low-melting metals of gallium, indium, tin, and bismuth.

  In this embodiment, as the liquid metal 106, a gallium-indium alloy having a thermal conductivity comparable to that of the metal material forming the temperature adjusting member 101 is used. The thermal conductivity of aluminum alloy or molybdenum exemplified as the metal material forming the temperature adjusting member 101 is about 130 W / m · K, and the thermal conductivity of stainless steel is about 15 W / m · K. On the other hand, the thermal conductivity of the gallium-indium alloy as the liquid metal 106 is about 40 W / m · K.

  The size of the opening of the concave portion 101a is larger than the size of the outer shape of the back surface 35c of the concave mirror 35. In the initial state, the bottom surface 101b of the recess 101a is in contact with the liquid metal 106 while the bottom surface 101b of the recess 101a is separated from the back surface 35c of the concave mirror 35 by a predetermined distance (for example, 1 mm). In the present embodiment, the shape of the recess 101a in plan view is rectangular, but the shape of the recess 101a in plan view is the concave mirror 35 as long as the temperature adjusting member 101 can accommodate the concave mirror 35 without contacting it. You may change suitably according to this shape.

  The refrigerant pipe 102 is formed of a flexible member such as a bellows member. The refrigerant pipe 102 circulates the refrigerant supplied from the refrigerant supply device 64 in the cooling jacket 103 and circulates the refrigerant discharged from the cooling jacket 103 to the refrigerant supply device 64. The refrigerant supply device 64 controls the flow rate and temperature of the refrigerant supplied to the refrigerant pipe 102 in accordance with a control signal from the main control device 55. The cooling jacket 103 is disposed in close contact with the Peltier element 104 and cools the Peltier element 104 with a refrigerant flowing through the inside.

  The Peltier element 104 is bonded to the bottom surface of the temperature adjusting member 101 with a paste having high thermal conductivity. The Peltier element 104 adjusts the temperature of the temperature adjustment member 101 by exchanging heat with the temperature adjustment member 101. The main controller 55 controls the cooling temperature of the temperature adjusting member 101 by the Peltier element 104 by controlling the polarity and intensity of the current flowing through the Peltier element 104 based on an electrical signal from a temperature sensor (not shown).

  The drive mechanism 105 is driven by the cooling mechanism drive system 63 and moves along the direction in which the temperature adjustment member 101 approaches or separates from the concave mirror 35 (Z direction in the present embodiment). As described above, since the refrigerant pipe 102 is formed of a flexible member, the refrigerant pipe 102 operates following the raising / lowering operation of the temperature adjustment member 101. The main controller 55 controls the operation of the drive mechanism 105 via the cooling mechanism drive system 63 based on an electrical signal from a temperature sensor (not shown).

  The mirror temperature control apparatus 100 having such a configuration adjusts the temperature of the concave mirror 35 by operating as described below. Hereinafter, the operation of the mirror temperature control apparatus 100 will be described with reference to FIGS. 5 to 7.

  FIG. 5 is a diagram for explaining the operation of the mirror temperature adjusting device 100 when the temperature of the concave mirror 35 rises due to an increase in the thermal load of the concave mirror 35. As shown in FIG. 5, the main controller 55 moves (increases) the temperature adjustment member 101 in a direction approaching the back surface 35 c of the concave mirror 35 by controlling the drive mechanism 105 via the cooling mechanism drive system 63. Let At that time, the main controller 55 may decrease the temperature of the temperature adjustment member 101 by controlling the Peltier element 104.

  As the temperature adjustment member 101 rises, the distance between the back surface 35c of the concave mirror 35 and the bottom surface 101b of the concave portion 101a becomes shorter than the initial state, and the gap between the back surface 35c of the concave mirror 35 and the bottom surface 101b of the concave portion 101a is reduced. The effective thickness of the intervening liquid metal 106 is reduced. Thereby, the heat transfer coefficient of the liquid metal 106 is increased. Specifically, when the effective thickness of the liquid metal 106 is ½ of the normal thickness, the thermal conductivity of the liquid metal 106 does not change, but the temperature difference between the temperature adjustment member 101 and the concave mirror 35 is increased. Even if they are the same, the amount of heat transported by the liquid metal 106 is doubled. Therefore, according to such an operation, the concave mirror 35 is rapidly cooled, and the temperature of the concave mirror 35 can be cooled with high responsiveness.

  When the temperature adjusting member 101 is raised, the liquid metal 106 interposed between the temperature adjusting member 101 and the concave mirror 35 may be pushed out by the concave mirror 35 and flow out of the concave portion 101a. However, in this embodiment, by forming the size of the opening of the concave portion 101a to be larger than the size of the outer shape of the back surface 35c of the concave mirror 35, the storage portion 101c that stores the liquid metal 106 in the concave portion 101a. Is formed. Thereby, when the temperature adjustment member 101 is raised, the liquid metal 106 pushed out by the concave mirror 35 moves to the storage portion 101c side and is stored, so that the liquid metal 106 can be prevented from flowing out of the recess 101a.

  FIG. 6 is a diagram for explaining the operation of the mirror temperature adjusting device 100 when the temperature of the concave mirror 35 is decreased due to a decrease in the thermal load on the concave mirror 35. As shown in FIG. 6, the main controller 55 moves (lowers) the temperature adjustment member 101 in a direction away from the back surface 35 c of the concave mirror 35 by controlling the drive mechanism 105 via the cooling mechanism drive system 63. Let At this time, when the thermal load on the concave mirror 35 decreases, the main controller 55 may increase the temperature of the temperature adjustment member 101 by controlling the Peltier element 104.

  As the temperature adjustment member 101 moves down, the distance between the back surface 35c of the concave mirror 35 and the bottom surface 101b of the concave portion 101a becomes longer than the initial state, and between the back surface 35c of the concave mirror 35 and the bottom surface 101b of the concave portion 101a. The effective thickness of the intervening liquid metal 106 increases. Thereby, the heat transfer coefficient of the liquid metal 106 is reduced. Specifically, when the effective thickness of the liquid metal 106 is twice that of normal, the thermal conductivity of the liquid metal 106 does not change, but the temperature difference between the temperature adjustment member 101 and the concave mirror 35 is the same. Even in this case, the amount of heat transported by the liquid metal 106 is reduced to ½. Therefore, according to such an operation, even if the temperature of the temperature adjusting member 101 or the liquid metal 106 does not rise rapidly, the cooling efficiency of the concave mirror 35 is lowered, and the temperature of the concave mirror 35 is raised with high responsiveness. be able to.

  FIG. 7 is a diagram for explaining the operation of the mirror temperature control apparatus 100 when the concave mirror 35 is thermally insulated. As shown in FIG. 7, when the concave mirror 35 is thermally insulated, the main controller 55 controls the drive mechanism 105 via the cooling mechanism drive system 63 so that the back surface 35 c of the concave mirror 35 is the liquid metal 106. The temperature adjustment member 101 is moved (lowered) in a direction away from the temperature. According to such an operation, the concave mirror 35 and the temperature adjusting member 101 are thermally blocked by separating the back surface 35c of the concave mirror 35 from the liquid metal 106, so that the concave mirror 35 is thermally insulated. By thus physically separating the concave mirror 35 and the liquid metal 106, the concave mirror 35 can be easily attached and detached when performing maintenance work, for example.

  As is clear from the above description, the mirror temperature adjustment device 100 according to the first embodiment of the present invention is arranged at a predetermined distance from the concave mirror 35 that reflects the EUV light EL, and A temperature adjustment member 101 that adjusts the temperature of the liquid metal 106 interposed therebetween, and a drive mechanism 105 that moves the temperature adjustment member 101 in a direction close to or away from the concave mirror 35 are provided. According to such a configuration, since the liquid metal 106 has high thermal conductivity, the amount of heat of the concave mirror 35 can be efficiently exhausted, and the temperature of the concave mirror 35 can be adjusted.

  Further, when the thermal load of the concave mirror 35 is greatly changed, in addition to controlling the temperature of the temperature adjustment member 101, the heat transfer coefficient of the liquid metal 106 is also increased by moving the temperature adjustment member 101 by the drive mechanism 105. Since it can be changed, the temperature of the concave mirror 35 can be adjusted with good responsiveness. Further, since the temperature of the concave mirror 35 is adjusted via the liquid metal 106, the vibration of the refrigerant for cooling the Peltier element 104 is not directly transmitted to the concave mirror 35, and the image of the concave mirror 35 is imaged. Vibration that affects the characteristics can be eliminated.

[Modification]
Next, a configuration of a modified example of the mirror temperature adjustment device 100 will be described with reference to FIGS. FIG. 8 is a plan view showing a configuration of a modified example of the mirror temperature control apparatus shown in FIG. FIG. 9 is a cross-sectional view taken along line AA of the mirror temperature control apparatus shown in FIG. FIG. 10 is a schematic diagram showing an illumination area of dipole illumination.

  The in-plane distribution of the thermal load of the concave mirror 35 changes according to the illumination conditions. For example, when the illumination condition is normal illumination, the EUV light illuminates the central portion of the reflecting surface of the concave mirror 35. For this reason, the temperature distribution of the concave mirror 35 is the highest in the central portion as compared with the peripheral portion, and gradually becomes lower from the central portion toward the peripheral portion. On the other hand, when the illumination condition is dipole illumination, the EUV light has two circular regions Rx1 and Rx2 that are symmetrical in the X direction across the optical axis AX on the reflection surface of the concave mirror 35, as shown in FIG. Illuminate. For this reason, the temperature distribution of the concave mirror 35 is the highest in the two circular regions Rx1 and Rx2 sandwiching the optical axis AX in the X direction as compared with the peripheral portion, and gradually decreases from the central portion toward the peripheral portion. .

  Therefore, in this modification, as shown in FIGS. 8 and 9, two divided blocks 101d that can be moved up and down independently from the bottom surface 101b are formed on the bottom surface 101b of the recess 101a. The divided block 101d is formed so as to face the back side region opposite to the region of the reflecting surface 35b of the concave mirror 35. Specifically, in the present modification, the two divided blocks 101d are formed at positions facing the back surface region opposite to the circular regions Rx1 and Rx2 on the reflective surface 35b. Each divided block 101d is provided with a divided drive mechanism 107 that moves the divided block 101d up and down independently from the bottom surface 101b. The split drive mechanism 107 is driven automatically or manually by the main controller 55 according to the illumination conditions.

  In addition, when raising / lowering the division | segmentation block 101d by the division | segmentation drive mechanism 107, the device which prevents the liquid metal 106 from leaking from the clearance gap between the bottom face 101b and the division | segmentation block 101d is required. However, since the surface tension of the liquid metal 106 is generally very large, the liquid metal 106 does not leak if the gap between the bottom surface 101b and the divided block 10d is small.

  In this modification, the split metal drive mechanism 107 is driven together with the drive mechanism 105 in accordance with the in-plane distribution of the thermal load of the concave mirror 35, thereby transferring the heat of the liquid metal 106 in the in-plane direction of the concave mirror 35. Change the rate. Specifically, when the illumination condition is dipole illumination, by bringing the divided block 101d closer to the back surface 35c side of the concave mirror 35, the back surface side of the concave mirror 35 opposite to the circular regions Rx1 and Rx2 described above. The amount of heat removed from the region is made larger than the amount of heat removed from the other back side region. According to such a configuration, even when the illumination condition is dipole illumination, the temperature of the concave mirror 35 can be adjusted with high responsiveness.

  In this modified example, the split block 101d is formed so as to face the back side region of the concave mirror 35 on the opposite side of the circular regions Rx1 and Rx2 assuming dipole illumination as the illumination condition. Is a normal illumination, the divided block 101d may be formed so as to face the back side region of the concave mirror 35 on the side opposite to the central portion where the EUV light is illuminated. Further, two or more divided blocks 101d may be formed by dividing the bottom surface 101b of the recess 101a in a matrix so as to be able to cope with various illumination conditions.

  Further, in this modification, the heat transfer coefficient of the liquid metal 106 in the in-plane direction of the concave mirror 35 is changed by forming two divided blocks 101d that can be moved up and down independently from the bottom surface 101b. As shown in FIG. 4, even if the convex portion 101e is formed on the bottom surface 101b and the temperature adjusting member 101 is moved up and down by the drive mechanism 105, the heat transfer coefficient of the liquid metal 106 in the in-plane direction of the concave mirror 35 can be changed. Good. Even in this case, the amount of heat removed from the back surface region of the concave mirror 35 facing the convex portion 101e can be made larger than the amount of heat removed from the other back surface region.

[Second Embodiment]
Next, with reference to FIG. 12 and FIG. 13, the structure of the mirror temperature control apparatus which is the 2nd Embodiment of this invention is demonstrated. Note that the mirror temperature adjustment device of the present embodiment is for adjusting the temperature of the curved mirror 34 shown in FIG. 1, and is applied to a mirror having a reflective surface that reflects EUV light on the lower surface (−Z direction) side. can do.

  FIG. 12 is a plan view showing a configuration of a mirror temperature control apparatus according to the second embodiment of the present invention. 13 is a cross-sectional view taken along line AA of the mirror temperature control apparatus shown in FIG. As shown in FIGS. 12 and 13, the mirror temperature adjustment device 200 according to the second embodiment of the present invention is the first embodiment in that a concave portion that holds the liquid metal 106 is formed in the curved mirror 34. It is different from the configuration of the mirror temperature control device 100 as a form. That is, in the present embodiment, a recess 34d is formed on the back surface 34c of the curved mirror 34, and the liquid metal 106 is held in the recess 34d.

  Further, the size of the opening of the recess 34d is larger than the size of the outer shape of the temperature adjustment member 101. In the initial state, the temperature adjustment member 101 is in contact with the liquid metal 106 while being separated from the bottom surface 34e of the concave portion 34d of the curved mirror 34 by a predetermined distance. Further, by forming the size of the opening of the concave portion 34d to be larger than the size of the outer shape of the temperature adjusting member 10, a storage portion 34f for storing the liquid metal 106 is formed in the concave portion 34d. The reservoir 34f can suppress the liquid metal 106 from flowing out of the recess 34d when the temperature adjustment member 101 is brought close to the back surface 34c of the curved mirror 34. The other configuration and operation of the mirror temperature adjustment device 200 are the same as the configuration and operation of the mirror temperature adjustment device 100 according to the first embodiment.

  That is, the mirror temperature control apparatus 200 according to the second embodiment of the present invention is arranged at a predetermined distance from the curved mirror 34 that reflects the EUV light EL, as in the first embodiment. A temperature adjusting member 101 that adjusts the temperature of the liquid metal 106 interposed therebetween, and a drive mechanism 105 that moves the temperature adjusting member 101 in a direction close to or away from the curved mirror 34. And according to such a structure, since the liquid metal 106 has high thermal conductivity, the heat quantity which the curved mirror 34 has can be efficiently exhausted, and the temperature of the curved mirror 34 can be adjusted with sufficient responsiveness.

  Further, when the thermal load of the curved mirror 34 changes greatly, in addition to controlling the temperature of the temperature adjusting member 101, the curved mirror is moved from the temperature adjusting member 101 side by moving the temperature adjusting member 101 by the drive mechanism 105. Since the heat transfer coefficient of the liquid metal 106 to the side 34 can also be changed, the temperature of the curved mirror 34 can be adjusted with good responsiveness. Further, since the temperature of the curved mirror 34 is adjusted via the liquid metal 106, the vibration of the refrigerant for cooling the Peltier element 104 is not directly transmitted to the curved mirror 34, and the image of the curved mirror 34 is imaged. Vibration that affects the characteristics can be eliminated.

  In this embodiment as well, as shown in FIG. 14, a divided block 101 d is formed on the surface of the temperature adjustment member 101 a facing the bottom surface 34 e of the recess 34 d, and according to the in-plane distribution of the thermal load of the curved mirror 34. The heat transfer coefficient of the liquid metal 106 in the in-plane direction of the curved mirror 34 may be changed by driving the split drive mechanism 107 together with the drive mechanism 105. Although not shown in the figure, in the same manner as the modification shown in FIG. 11, the convex portion 101 e is formed on the bottom surface 101 b and the temperature adjusting member 101 is moved up and down by the drive mechanism 105, so that the curved mirror 34 in the in-plane direction. The heat transfer coefficient of the liquid metal 106 may be changed.

  The embodiment to which the invention made by the present inventors has been described has been described above, but the present invention is not limited by the description and drawings that form part of the disclosure of the present invention according to the above embodiment. For example, in the present embodiment, the liquid metal 106 is interposed between the temperature adjustment member 101 and the mirror whose temperature is to be adjusted, but the substance interposed between the mirror and the temperature adjustment member 101 is liquid. The metal 106 is not limited.

  For example, when the present invention is applied to a mirror provided in an apparatus other than the exposure apparatus, the heat transfer coefficient of the substance interposed between the mirror and the temperature adjustment member 101 changes as the temperature adjustment member 101 moves up and down. As long as it is a substance to be used, a fluid other than liquid metal such as gas or water can be used.

  In this embodiment, the thermal conductivity of the temperature adjusting member 101 is approximately the same as the thermal conductivity of the substance interposed between the mirrors, but the thermal conductivity of the substance interposed between the mirrors. The rate may be much larger than the thermal conductivity of the temperature adjustment member 101. However, in this case, as in the modification shown in FIG. 9, when the mirror temperature is locally controlled by the divided block 101d, the up-and-down direction of the divided block 101d is opposite to the above-described up-and-down direction. Become. That is, when the temperature of the mirror is locally decreased, the divided block 101d is moved in a direction away from the mirror. On the other hand, when the temperature of the mirror is locally increased by the divided block 101d, the divided block 101d is moved in the direction approaching the mirror.

  Thus, other embodiments, examples, combinations of embodiments, operation techniques, and the like made by those skilled in the art based on the above-described embodiments are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Exposure apparatus 34 Curved surface mirror 34a, 35a Holding part 34b, 35b Reflecting surface 34c, 35c Back surface 34d, 101a Recessed part 34e, 101b Bottom surface 34f, 101c Storage part 35 Concave mirror 100, 200 Mirror temperature control apparatus 101 Temperature adjustment member 101d Divided block 101e Convex part 102 Refrigerant tube 103 Cooling jacket 104 Peltier element 105 Drive mechanism 106 Liquid metal ILS Illumination optical system PO Projection optical system

Claims (16)

A temperature adjusting mechanism that is arranged at a predetermined interval with respect to a mirror that reflects light and adjusts the temperature of a fluid interposed between the mirror and the mirror;
A drive mechanism for moving the temperature adjustment mechanism in a direction close to the mirror or in a direction away from the mirror;
A mirror temperature control device comprising:   The temperature adjustment mechanism has a facing surface facing the back surface opposite to the reflecting surface of the mirror, and the driving mechanism is arranged in a direction close to the back surface of the mirror or in a direction away from the back surface of the mirror. The mirror temperature control device according to claim 1, wherein the mirror temperature control device moves on the opposing surface.   The opposed surface is divided into a plurality of divided opposed surfaces, and the drive mechanism moves at least one divided opposed surface of the plurality of divided opposed surfaces in a direction close to or away from the back surface. The mirror temperature control apparatus according to claim 2, further comprising a split driving mechanism.   The mirror temperature control device according to claim 2, wherein the facing surface includes a convex portion in which a part of the facing surface protrudes toward the back surface of the mirror.   The mirror temperature control apparatus according to any one of claims 2 to 4, wherein the temperature adjustment mechanism includes a fluid holding portion that holds the fluid.   The mirror temperature adjustment device according to claim 5, wherein the temperature adjustment mechanism includes a temperature adjustment member having a recess having the opposed surface as a bottom surface, and the recess functions as the fluid holding unit.   The mirror temperature adjustment device according to claim 6, wherein the drive mechanism moves the concave portion in a direction away from the back surface to separate the mirror and the fluid.   The mirror temperature adjusting device according to any one of claims 2 to 4, wherein the mirror includes a fluid holding unit that holds the fluid.   The mirror temperature control device according to claim 8, wherein the fluid holding portion is a recess formed on a back surface of the mirror.   The fluid holding section includes a storage section that stores fluid pushed out from between the temperature adjustment mechanism and the mirror as the temperature adjustment mechanism moves in a direction approaching the mirror. Item 10. The mirror temperature control device according to any one of Items 5 to 9.   The said temperature is a liquid metal, The mirror temperature control apparatus as described in any one of Claims 1-10 characterized by the above-mentioned.   The mirror temperature adjustment device according to claim 1, wherein the temperature adjustment mechanism is a cooling adjustment mechanism that cools the fluid. Multiple mirrors,
A mirror temperature adjusting device that is provided on at least one of the plurality of mirrors and adjusts the temperature of the at least one mirror;
With
The mirror temperature control device is
A temperature adjusting mechanism that is arranged at a predetermined distance from the mirror and adjusts the temperature of the fluid interposed between the mirror and the mirror;
A drive mechanism for moving the temperature adjustment mechanism in a direction close to the mirror or in a direction away from the mirror;
An optical system comprising: Multiple mirrors,
The mirror temperature adjustment device according to any one of claims 1 to 12, provided on at least one of the plurality of mirrors,
An optical system comprising: An extreme ultraviolet light source that emits extreme ultraviolet light;
A plurality of mirrors for guiding the extreme ultraviolet light irradiated by the extreme ultraviolet light source to the irradiated surface;
A mirror temperature adjusting device that is provided on at least one of the plurality of mirrors and adjusts the temperature of the at least one mirror;
With
The mirror temperature control device is
A temperature adjusting mechanism that is arranged at a predetermined distance from the mirror and adjusts the temperature of the fluid interposed between the mirror and the mirror;
A drive mechanism for moving the temperature adjustment mechanism in a direction close to the mirror or in a direction away from the mirror;
An exposure apparatus comprising: In an exposure apparatus comprising: a first optical system that irradiates a mask on which a pattern is formed with exposure light; and a second optical system that exposes a substrate with the exposure light through the pattern;
At least one of the first optical system and the second optical system is provided on at least one mirror and the at least one mirror, and the mirror temperature adjusting device according to any one of claims 1 to 12. An exposure apparatus comprising: