JP2009010174A - Exposure apparatus and atmosphere replacement method thereof - Google Patents

Abstract

An exposure apparatus and an atmosphere replacement method for reducing exposure of particles to an optical element during supply / exhaust of a vacuum chamber are provided.
In an exposure apparatus 100 that exposes a pattern of a reticle R onto a wafer W in a vacuum environment, a vacuum chamber 2 for maintaining an optical path C in a vacuum, a mirror 21 disposed in the vacuum chamber 2, a mirror The temperature measurement device 46 that measures the temperature of the mirror 21, the radiation plate 51 that can control the temperature of the mirror 21 by radiation, the temperature measurement device 46 that measures the temperature of the radiation plate 51, and the measurement result by the temperature measurement device 46 are acquired. The control unit 71 controls the temperature of the radiation plate 51. The control unit 71 controls the mirror 21 during exhaust and supply of the vacuum chamber 2 so that the temperature of the mirror 21 is constant during exposure. The temperature of the radiation plate 51 is controlled so that the temperature of the radiation plate 51 is lower than the temperature of the above.
[Selection] Figure 1

Description

  The present invention relates to an exposure apparatus and an atmosphere replacement method thereof.

  In order to meet the recent demand for higher resolution, an EUV exposure apparatus using extreme ultraviolet (EUV) light having a shorter wavelength than ultraviolet light has been proposed. The EUV exposure apparatus maintains a vacuum chamber in a vacuum environment, and exposes a pattern of an original (a mask or a reticle, hereinafter referred to as “reticle”) onto a wafer (substrate). In order to prevent thermal distortion and thermal damage of optical elements that are exposed to high-intensity EUV light in a vacuum environment, a radiation plate is placed in the vicinity of the optical elements such as mirrors, reticles, wafers, their holding parts and chucks. It is also known to dissipate heat.

  At the start and end of exposure of the exposure apparatus, the atmosphere in the vacuum chamber is replaced between the atmospheric pressure environment and the vacuum environment with the EUV light source turned off. Specifically, the atmosphere in the vacuum chamber is replaced from the atmospheric pressure environment to the vacuum environment (exhaust) at the start of exposure, and the atmosphere in the vacuum chamber is replaced from the vacuum environment to the atmospheric environment (supply air) at the end of exposure. However, there is a need for means for reducing or preventing particles from being rolled up and adhering to the optical element during these air supply and exhaust. In this regard, Non-Patent Document 1 proposes a method for reducing the adhesion of particles to a substrate using a thermophoretic force.

Other conventional techniques include Patent Documents 1 to 3 and Non-Patent Document 2.
Special registration 2886521 JP 2006-173245 A JP 2004-281653 A Co-authored by Kikuo Okuyama, Hiroaki Masuda, and Seiji Morooka, “New System Chemical Engineering, Fine Particle Engineering”, published by Ohmsha, May 1992, P106-107 Supervised by Satoshi Hattori, “Surface cleaning technology for new silicon wafers” published by Realize Science and Technology Center, May 2000, P72-74

  In order to satisfy the thermophoretic force equation disclosed in Non-Patent Document 1, it is necessary to dispose a dust collector that is kept at a low temperature and has a predetermined size in the vicinity of the optical element. However, a space for arranging such a dust collector cannot be provided in the vacuum chamber of the EUV exposure apparatus for miniaturization. Therefore, there is a problem that the thermophoretic force in the vicinity of the optical element cannot be utilized to the maximum extent.

  The present invention relates to an exposure apparatus that reduces adhesion of particles to an optical element during supply and exhaust of a vacuum chamber, and an atmosphere replacement method thereof.

  An exposure apparatus according to an aspect of the present invention is an exposure apparatus that exposes a pattern of an original on a substrate in a vacuum environment, a vacuum chamber for maintaining an optical path in a vacuum, an optical element disposed in the vacuum chamber, A first temperature measuring unit for measuring the temperature of the optical element; a radiation plate capable of controlling the temperature of the optical element by radiation; a second temperature measuring unit for measuring the temperature of the radiation plate; And a control unit that acquires a measurement result by the second temperature measurement unit and controls the temperature of the radiation plate, and the control unit is configured so that the temperature of the optical element is constant during exposure. The temperature of the radiation plate is controlled so that the temperature of the radiation plate is lower than the temperature of the optical element when the vacuum chamber is exhausted or supplied.

  Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  ADVANTAGE OF THE INVENTION According to this invention, the exposure apparatus which reduces that a particle adheres to an optical element at the time of supply / exhaust of a vacuum chamber, and its atmosphere replacement method can be provided.

  Hereinafter, an exposure apparatus 100 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic sectional view of the exposure apparatus 100. The exposure apparatus 100 is a projection exposure apparatus that exposes the pattern of the reticle R onto the wafer W in a vacuum environment using light from a light source. In this embodiment, the light from the light source is EUV light L having a wavelength of 5 nm to 20 nm, for example, 13.4 nm.

  The exposure apparatus 100 includes an illumination device (not shown), a vacuum chamber 2, a reticle stage 10, a projection optical system 20, a wafer stage 15, exhaust devices 31 to 35, a measurement system 40, and radiation plates 51 to 56. , A temperature adjusting unit, and a control system 70.

  A lighting device (not shown) includes an EUV light source and an illumination optical system.

  As the EUV light source, a laser plasma light source (not shown) is used. In this method, a target material supplied by a target supply device placed outside the vacuum chamber 2 is irradiated with high-intensity pulsed laser light generated from a pulse laser for excitation to generate high-temperature plasma, and EUV light emitted therefrom. Is to be used. As the target material, a metal thin film, an inert gas, a droplet, or the like is used, and is supplied into the vacuum vessel by means such as a gas jet. The type of EUV light source is not limited, such as a discharge plasma light source.

  The illumination optical system includes a plurality of multilayer films or oblique incidence mirrors, an optical integrator, and the like, and uniformly illuminates the reticle R with a predetermined numerical aperture. FIG. 1 shows only the deflection mirror 1 that is a part of the illumination optical system. The deflection mirror 1 deflects the EUV light L and introduces it into the reticle R. The deflection mirror 1 is provided with a radiation plate (not shown) in the vicinity, and the radiation plate is cooled by a cooling means such as a Peltier element (not shown) or a refrigerant. Such a configuration is the same as the relationship between each mirror of the projection optical system 20 and the radiation plate.

  The vacuum chamber 2 is a vacuum container that maintains the optical path C of the EUV light L, which is exposure light, in a vacuum. The vacuum chamber 2 includes a partition wall and an aperture member having an opening through which the EUV light L can pass, and is configured to be able to generate a differential pressure in the partitioned internal space. The vacuum chamber 2 is partitioned into vacuum chambers 2a to 2d and is made of, for example, aluminum.

Vacuum chamber 2a has a wall surface 2a ₁ inner defining the reticle stage space 3a, the reticle replacement window 4a to loading and unloading the reticle R is provided. The reticle stage space 3a accommodates the reticle R, the reticle stage 10, and the reticle chuck 12.

The vacuum chamber 2b has an inner wall surface 2b ₁ that defines the first optical path space 3b. Between the reticle stage space 3a and the first optical path space 3b, the partition wall 2e ₁ substantially parallel to the X direction, the partition walls 2e ₂ is provided which projects from the partition wall 2e ₁ to the reticle stage space 3a.

The wafer W side of the partition wall 2e ₁ second mirror 22 of the projection optical system 20 is fixed. The partition wall 2e ₂ has an opening through which illumination light for illuminating the reticle R and exposure light emitted from the reticle R can pass. In order to generate a differential pressure between the reticle stage space 3a and the first optical path space 3b, this embodiment, the shortest distance between the barrier ribs 2e ₂ and the reticle R surface (which can flow into and out of the gas gap) It is set to 1 mm or less.

The first optical path space 3b houses the deflection mirror 1 of the illumination optical system and the first to fourth mirrors 21 to 24 of the projection optical system 20. In the first optical path space 3b, inner walls 2e ₃ and 2e ₄ connected to the inner wall surface 2b ₁ extend substantially parallel to the X direction. The reticle R side inner wall 2e ₃ is fixed first mirror 21, the wafer W side of the inner wall 2e ₄ fourth mirror 24 is fixed.

  With this configuration, a differential exhaust system can be formed between the reticle stage space 3a and the first optical path space 3b, and the amount of outgas generated from the reticle stage space 3a can be suppressed from entering the first optical path space 3b.

Vacuum chamber 2c has a wall 2c ₁ inner defining a second optical path space 3c. Between the first optical path space 3b and the second optical path space 3c, a partition wall 2e ₅ and a diaphragm member 2e _{6 that} are substantially parallel to the X direction are provided. The reticle R side of the partition wall 2e ₅ third mirror 23 are fixed. The aperture member 2e ₆ has an opening through which light that reflects the reticle pattern can pass, and protrudes into both the first and second optical path spaces 3b and 3c. When the aperture member 2e ₆ connects the first optical path space 3b and the second optical path space 3c, a differential pressure can be generated between the two spaces.

The second optical path space 3 c houses the fifth and sixth mirrors 25 and 26 of the projection optical system 20. A sixth mirror 26 is fixed to the partition wall 2e _{5 on} the wafer W side. The fifth mirror 25 is fixed to the reticle R side of the partition wall 2e _7. The partition 2e ₇ is a partition provided between the second optical path space 3c and the wafer stage space 3d.

Vacuum chamber 2d has a wall surface 2d ₁ inner defining a wafer stage space 3d, wafer replacement window 4b for loading and unloading the wafer W is provided. The wafer stage space 3d accommodates the wafer W, the wafer stage 15, and the wafer chuck 17. A partition wall 2e ₇ having an opening for allowing exposure light to pass therethrough is provided between the second optical path space 3c and the wafer stage space 3d. The partition wall 2e ₇ extends substantially parallel to the X direction.

  The reticle R is a reflective reticle, and is supported by the reticle stage 10 and driven in the scanning direction (X direction). Diffracted light emitted from the reticle R is reflected by the projection optical system 20 and projected onto the wafer W. The reticle R and the wafer W are arranged in an optically conjugate relationship. Since the exposure apparatus 100 is a step-and-scan exposure apparatus, the reticle R and the wafer W are scanned synchronously to reduce and project the reticle pattern onto the wafer W.

  The reticle R is held by the reticle chuck 12 on the reticle stage 10. The reticle chuck 12 is an electrostatic chuck, and attracts and holds the reticle R by electrostatic attraction force. The reticle R is held by the reticle chuck 12 so that the pattern surface is the lower side or the projection optical system 20 side in FIG.

  The reticle stage 10 has a mechanism that moves at high speed in the X direction. The reticle stage 10 has a fine movement mechanism in the XYZ direction and the rotation direction around each axis, and is configured so that the reticle R can be positioned. The position and orientation of reticle stage 10 are controlled based on the measurement result of a laser interferometer (not shown). Here, the scanning direction in the reticle R or wafer W plane is the X direction, the X direction and the direction perpendicular to the paper plane are the Y direction, and the direction perpendicular to the reticle R or wafer W plane is the Z direction.

  The projection optical system 20 projects the reticle pattern onto the wafer. Although the projection optical system 20 of the present embodiment includes the first to sixth mirrors 21 to 26 described above, the number of mirrors is not limited to this. In this embodiment, the mirror of the projection optical system 20 is a target for heat dissipation during exposure and a target for dust collection during supply and exhaust. However, the heat dissipation and dust collection target of the present invention is not limited to this.

  Hereinafter, instead of describing the heat dissipation and dust collection mechanism of all the mirrors 21 to 26 of the projection optical system 20, the heat dissipation and dust collection mechanism of the first mirror 21 will be described as a representative. However, this description also applies to other mirrors of the projection optical system 20 or other optical elements disposed in the vacuum chamber 2.

  Referring to FIG. 2, a radiation plate 51 is disposed around and in the vicinity of the first mirror 21. The first mirror 21 radiates heat during exposure and collects dust during supply and exhaust. A radiation plate 52 is disposed around and in the vicinity of the second mirror 22 to radiate heat from the second mirror 22 during exposure and to collect dust during supply and exhaust. A radiation plate 53 is disposed around and in the vicinity of the third mirror 23. The third mirror 23 dissipates heat during exposure and collects dust during supply and exhaust. A radiation plate 54 is disposed around and in the vicinity of the fourth mirror 24. The fourth mirror 24 dissipates heat during exposure and collects dust during supply and exhaust. A radiating plate 55 is disposed around and in the vicinity of the fifth mirror 25. The fifth mirror 25 radiates heat during exposure and collects dust during supply and exhaust. A radiation plate 56 is disposed around and in the vicinity of the sixth mirror 26. The sixth mirror 26 radiates heat during exposure and collects dust during supply and exhaust.

  Hereinafter, the first mirror 21 and the radiation plate 51 will be described with reference to FIG. Here, FIG. 2 is a schematic enlarged sectional view of the vicinity of the first mirror 21. The structure shown in FIG. 2 (such as a holding unit and a temperature sensor) is generally common to each mirror and radiation plate pair.

  In FIG. 2, the first mirror 21 has an upper surface 21a and a bottom surface 21b. The first mirror 21 receives the EUV light L in the reflection area of the upper surface 21a, and is supported by the base 27 via a plurality of holding portions 28 in the vicinity of the edge of the bottom surface 21b. A temperature sensor (first temperature measurement unit) 47 is fixed at the center of the bottom surface 21 b of the first mirror 21.

Base 27, for example, is fixed to the inner wall 2e ₃ of the vacuum chamber 2b has a rectangular plate shape or a disk shape. The holding unit 28 has a circle, a square, a rectangle, a track shape, or the like in cross section with respect to a plane perpendicular to the paper surface, and extends in the Z direction. The shape, position, and number of the holding portions 28 are not limited.

  The radiation plate 51 is supported by the base 27 via the holding portion 57. It is fixed to the bottom 51c of the holding part 57. The holding unit 57 has a cross section with respect to a plane perpendicular to the paper surface, such as a circle, a square, a rectangle, or a track shape, and extends in the Z direction. The shape, position, and number of the holding portions 57 are not limited.

  The radiation plate 51 has a substantially casing shape and houses the first mirror 21. The radiation plate 51 includes an upper part 51a, a side part 51b having one or more surfaces, and a bottom part 51c. If the radiation plate 51 has a rectangular parallelepiped shape, it has side parts 51b having four side surfaces, and if it has a cylindrical shape, it has side parts 51b having one side surface. However, the shape of the radiation plate 51 is not limited.

The top 51a has an opening 51a _1. The EUV light L passes through the opening 51 a ₁ and reaches the first mirror 21, is reflected by the first mirror 21, passes through the opening 51 a ₁ , and reaches the second mirror 22. That is, the opening 51a ₁ can be arranged on the optical path C of the EUV light. The reason that “arrangement is possible” is that the opening 51 a ₁ may move as described later with reference to FIG. 8.

  The temperature adjustment unit includes a radiation plate cooling unit, an optical element heating unit, and a vacuum chamber cooling unit. The radiation cooling unit has a function of cooling the radiation plate 51. In the embodiment shown in FIG. 2, the radiation plate cooling unit includes pipes 60 and 61. In the embodiment shown in FIG. 3, the radiation plate cooling unit includes a pipe 62, a cooling jacket 63, and a Peltier element 64. Here, FIG. 3 is a schematic sectional view showing a modification of the radiation plate cooling section shown in FIG.

  The optical element heating unit has a function of heating the optical element. In the embodiment shown in FIG. 4, the optical element heating unit includes an optical element heating unit 65 that heats the first mirror 21. Here, FIG. 4 is a schematic cross-sectional view of the first mirror 21 having the optical element heating unit 65. The vacuum chamber cooling section has a function of cooling the wall surface of the vacuum chamber 2 (or a part thereof), and has pipes 66 and 67 in the embodiment shown in FIG. Here, FIG. 5 is a schematic sectional view of an exposure apparatus 100A which is a modification of the exposure apparatus 100 shown in FIG.

In Figure 2, a portion of the radiation plate cooling portion of the temperature adjustment section is connected to the outer surface 51b ₁ of the side 51b. As described above, the radiation plate cooling unit shown in FIG. Pipe 60, the flow passage 60a of the refrigerant is formed in the pipe 60 is fixed to the outer surface 51b ₁ of the side 51b. The piping 60 can cool the side part 51b of the radiation plate 51 by the refrigerant flowing through the flow path 60a.

  The pipe 60 and the side part 51b may be integrated. The size and number of the pipes 60 and the position of the radiation plate 51 to which the pipes 60 are connected are not limited. The pipe 60 is connected to the pipe 61 and covers the periphery of the side portion 51b. In FIG. 2, for example, the refrigerant passes from a constant temperature circulating water tank 74 described later through the right pipe 61 and the flow path 60 a of the pipe 60, and returns to the constant temperature circulating water tank 74 via the flow path 60 a and the pipe 61 of the left pipe 60. . The temperature of the refrigerant is controlled by a constant temperature circulating water tank 74, and water, nitrogen gas, and other refrigerants known in the art can be used.

Bottom 51c has a plurality of openings 51c _1, and the inner surface 51c _2, and an outer surface 51c _3. The openings 51c ₁ each holding portion 28 penetrates. In the center of the inner surface 51c ₂ of the bottom portion 51c temperature sensor (second temperature measuring unit) 48 is fixed. The holding portion 57 is fixed to the center of the outer surface 51c ₃ of the bottom portion 51c.

  The exhaust devices 31 to 35 are constituted by a turbo molecular pump or the like. The exhaust devices 31 to 35 are controlled to be exhausted and stopped by a control unit 71 of a control system 70 described later.

The exhaust device 31 is fixed to the vacuum chamber 2a, and independently exhausts the reticle stage space 3a to a vacuum degree (exposure vacuum degree) of 10 ⁻³ Pa to 10 ⁻⁷ Pa necessary for exposure and opens to the atmosphere. . In this way, the exhaust device 31 can replace the atmosphere of the reticle stage space 3a from the atmospheric environment to the vacuum environment, and from the vacuum environment to the atmospheric environment.

The pair of exhaust devices 32 and 33 is fixed to the vacuum chamber 2b, and independently exhausts the first optical path space 3b to the degree of vacuum for exposure and opens it to the atmosphere. More specifically, an exhaust device 32, is opened to the atmosphere while evacuating the reticle R side of the inner wall 2b ₂ of the first optical path space 3b independently to a vacuum degree of exposure. Exhaust system 33 is opened to the atmosphere while exhausting the wafer W side of the inner wall 2b ₂ of the first optical path space 3b independently to a vacuum degree of exposure. The number of exhaust devices is not limited to two. As described above, the exhaust devices 32 and 33 can replace the atmosphere of the first optical path space 3b from the atmospheric environment to the vacuum environment, and from the vacuum environment to the atmospheric environment.

  The exhaust device 34 is fixed to the vacuum chamber 2c, and independently exhausts the second optical path space 3c to the degree of vacuum for exposure and opens it to the atmosphere. In this way, the exhaust device 34 can replace the atmosphere of the second optical path space 3c from the atmospheric environment to the vacuum environment, and from the vacuum environment to the atmospheric environment.

  The exhaust device 35 is fixed to the vacuum chamber 2d, and independently exhausts the wafer stage space 3d to the degree of vacuum for exposure and opens it to the atmosphere. In this way, the exhaust device 34 can replace the atmosphere of the second optical path space 3c from the atmospheric environment to the vacuum environment, and from the vacuum environment to the atmospheric environment.

  The measurement system 40 has a pressure measurement system and a temperature measurement system.

  The pressure measurement system includes pressure sensors (pressure measurement units) 41 to 44. The pressure sensor 41 is fixed to the vacuum chamber 2a and measures the degree of vacuum in the reticle stage space 3a. The pressure sensor 42 is fixed to the vacuum chamber 2b and measures the degree of vacuum in the first optical path space 3b. The pressure sensor 43 is fixed to the vacuum chamber 2c and measures the degree of vacuum in the second optical path space 3c. The pressure sensor 44 is fixed to the vacuum chamber 2d and measures the degree of vacuum in the wafer stage space 3d.

The temperature measurement system includes a temperature measurement device 46 and temperature sensors 47 and 48. The temperature sensor 47 is fixed to the bottom surface 21 b of the first mirror 21 and measures the temperature of the first mirror 21. The temperature sensor 48 is fixed to the inner surface 51 c ₂ of the bottom 51 c of the radiation plate 51 and measures the temperature of the radiation plate 51. The temperature sensors 47 and 48 are arranged at positions where the XY coordinates are substantially the same, and the positions in the Z direction are different. The temperature sensors 47 and 48 are notified to the temperature measuring device 46. The temperature measuring device 46 notifies the control unit 71 of the result. The controller 71 can know the temperature gradient of the space S between the first mirror 21 and the radiation plate 51 from the results measured by the temperature sensors 47 and 48.

  The control system 70 includes a control unit 71, a memory 72, a timer 73, and a constant temperature circulating water tank 74.

  The control unit 71 is a CPU or MPU that controls each part of the exposure apparatus 100 and also performs dust collection control. The control unit 71 acquires the measurement results of the pressure sensors 41 to 44 and the measurement results of the temperature sensors 47 and 48 via the temperature measurement device 46. The control unit 71 acquires time information from the timer 73.

  The memory 72 is a ROM or RAM that stores programs and data necessary for control by the control unit 71. As such a program, there is a control method shown in FIGS. Such data includes 10 Pa, 10000 Pa, 10 seconds, 600 seconds, 10 K / cm, and the like used in the control method shown in FIGS.

  In particular, the timer 73 counts time (10 seconds to 600 seconds described later) required for dust collection control.

  The constant temperature circulating water tank 74 is connected to a pair of pipes 62, and supplies and collects the temperature-controlled refrigerant to the pipes 62. Thereby, the constant temperature circulating water tank 74 can control the temperature of the radiation plate 51. The temperature of the refrigerant supplied from the constant temperature circulating water tank 74 is controlled by the control unit 71.

  The controller 71 uses the constant temperature circulating water tank 74 to make the temperature of the radiation plate 51 lower than the temperature of the first mirror 21 according to the temperature of the first mirror 21 and the radiation plate 51 measured by the temperature measuring device 46. Thus, the temperature of the refrigerant is controlled.

In Figure 3, a portion of the radiation plate cooling portion of the temperature adjustment portion to the outer surface 51c ₁ of the bottom portion 51c is connected. As described above, the radiation plate cooling unit illustrated in FIG. 3 includes the pipe 62, the cooling jacket 63, and the Peltier element 64.

One end of the pipe 62 is connected to the constant temperature circulating water tank 74 as in FIG. 2, and the other end is connected to the cooling jacket 63. The bottom surface of the Peltier element 64 contacts the cooling jacket 63, and the upper surface of the Peltier element 64 is fixed to the outer surface 51 c ₁ of the bottom 51 c of the radiation plate 51.

  The Peltier element 64 has a function of cooling or heating the radiation plate 51 according to the supplied power. The Peltier element 64 is connected to the Peltier control device 75. For this reason, the control system 70A shown in FIG. 3 further adds a Peltier control device 75 to the control system 70 shown in FIG. The Peltier control device 75 has a function of controlling the power supplied to the Peltier element 64 and controlling the temperature of the radiation plate 51. The Peltier control device 75 is connected to the control unit 71, and the power controlled by the Peltier control device 75 is controlled by the control unit 71.

  In FIG. 3, for example, the refrigerant passes from the constant temperature circulating water tank 74 through the right pipe 62 and the cooling jacket 63 and returns to the constant temperature circulating water tank 74 from the left pipe 62. The temperature of the refrigerant is controlled by a constant temperature circulating water tank 74, and water, nitrogen gas, and other refrigerants known in the art can be used. The cooling jacket 63 cools the heat generated by the heat absorption of the Peltier element 64. When the temperature of the radiation plate 51 is adjusted, the first mirror 2 is cooled or heated by the radiation, and the temperature of the first mirror 21 can be adjusted.

  In FIG. 4, the optical element heating unit 65 of the temperature adjusting unit is provided outside the EUV light reflection region on the upper surface 21 a of the first mirror 21. The optical element heating unit 65 is in close contact with the first mirror 21 and heats the first mirror 21 by heat generation. As the optical element heating unit 65, for example, a heating wire or a Peltier element can be used. The optical element heating unit 65 is connected to the heating control device 76. For this reason, the control system 70B shown in FIG. 4 adds a heating control device 76 to the control system 70 shown in FIG. The heating control device 76 controls the temperature of the first mirror 21 by controlling the amount of heat generated by the heating unit 65. The heating control device 76 is connected to the control unit 71, and the amount of heat generated by the heating control device 76 is controlled by the control unit 71.

  At the time of supply and exhaust, the EUV light L is not irradiated and there is no heat source. For this reason, if the radiation plate 51 is cooled to provide a temperature difference gradient between the first mirror 21 and the radiation plate 51, the temperature of the first mirror 21 may be excessively lowered. In that case, the optical element heating unit 65 shown in FIG. 4 is used. The control unit 71 controls the amount of heat generated by the optical element heating unit 65 and the amount of heat absorbed from the first mirror 21 by radiation from the radiation plate 51 to be equal. Thereby, it is possible to prevent the temperature of the first mirror 21 from being excessively lowered. In FIG. 4, the optical element heating unit 65 is in close contact with the first mirror 21. However, as another heating unit, light other than EUV (for example, infrared rays) passing through the same optical path C as the EUV light L shown in FIG. ) Can be considered.

In FIG. 5, a part of the vacuum chamber cooling unit of the temperature adjusting unit is provided in the vacuum chamber 2c. As described above, the vacuum chamber cooling unit shown in FIG. Pipe 66, the flow passage 66a of the refrigerant is formed in the vacuum chamber 2c outer surface 2c in ₂ to fixed piping 66. The piping 66 can cool the vacuum chamber 2 by the refrigerant flowing through the flow path 66a.

  The wall surface of the pipe 66 and the vacuum chamber 2c may be integrated. The size and number of the pipes 66 and the position of the vacuum chamber 2 to which the pipes 66 are connected are not limited. However, in this embodiment, since the mirror of the projection optical system 20 is selected as an optical element to be collected, the piping 66 is provided only in the vacuum chambers 2b and / or 2c.

  The pipe 66 is connected to the pipe 67 and covers the periphery of the vacuum chamber 2c. In FIG. 5, for example, the refrigerant passes from a constant-temperature circulating water tank 77 to be described later through the right pipe 67 and the flow path 66 a of the pipe 66, and returns to the constant temperature circulating water tank 77 via the flow path 66 a and the pipe 67 of the left pipe 66. . The temperature of the refrigerant is controlled by a constant-temperature circulating water tank 77, and water, nitrogen gas, and other refrigerants known in the art can be used.

The constant temperature circulating water tank 77 is connected to a pair of pipes 67 and supplies and recovers the temperature-controlled refrigerant in the pipes 67. Thereby, the constant temperature circulating water tank 77 can adjust the temperature of the vacuum chamber 2. The temperature of the refrigerant supplied from the constant temperature circulating water tank 77 is controlled by the control unit 71. In addition, the effect of the refrigerant may extend from the pipe 66 through the inner wall surfaces 2 c ₁ and 2 b ₁ , the inner wall 2 e ₃ , the base 27, and the holding unit 28 of the vacuum chamber 2. In this case, in order to prevent the temperature of the wall surface (for example, the inner wall surface 2b ₁ ) of the vacuum chamber 2 from being equal to the temperature of the optical element (for example, the first mirror 21) as a dust collection target, the base 27 and the partition wall 2e a heat insulating member may be provided between the _1.

In FIG. 5, the temperature sensor (third temperature measuring portion) 49 is provided on the inner wall surface 2b ₁ of the vacuum chamber 2b. The temperature sensor 49 is connected to the temperature measuring device 46 shown in FIG. As a result, the control unit 71 can know the temperature of the inner wall surface 2 b ₁ facing the radiation plate 51 in the vacuum chamber 2 b via the temperature measuring device 46. The temperature sensor 48 shown in FIG. 2 measures the temperature of the inner surface of the radiation plate 51 facing the first mirror 21, but the radiation plate 51 is excellent in thermal conductivity, and the temperature of the inner surface and the outer surface on the back side thereof is high. Almost equal. Therefore, the measurement result of the temperature sensor 48 can be equated with the temperature of the outer surface of the side portion 51 b of the radiation plate 51. However, if the temperature of the outer surface of the side portion 51b of the radiation plate 51 of the temperature sensor 48 cannot be equated, a separate temperature sensor for measuring the temperature of the outer surface of the side portion 51b of the radiation plate 51 may be provided. As a result, the control unit 71 is to calculate the temperature gradient in the space between the wall surface 2b ₁ among which faces the radiation plate 51 of the outer surface and the vacuum chamber 2b of the side 51b of the radiation plate 51 via a temperature measuring device 46 Can do.

Instead of using the radiation plate 51 having the opening 51a ₁ as a complete opening, a radiation plate having a mesh 58 having a plurality of minute openings to the extent that the influence on the optical performance can be allowed as shown in FIG. (Mesh plate) 51A may be used. Here, FIG. 6 is a schematic sectional view showing a modification of FIG. Mesh 58, so as to close the opening portion 51a ₁ of the radiation plate 51 is provided on the upper portion 51a of the radiation plate 51A. It is desirable that the mesh 58 is joined to the upper portion 51a of the radiation plate 51A so that heat can be easily transmitted. As the mesh 58, a structure obtained by processing a plurality of minute openings in a thin metal plate or a mesh structure obtained by combining a plurality of metal wires can be employed. In this case, the mesh 58, which is a low-temperature object, can be brought close to the very vicinity of the region irradiated with the EUV light L of the first mirror 21, so that the particle reduction effect is improved.

As shown in FIG. 2, instead of using the radiation plate 51 having an opening 51a ₁ of the full opening, as shown in FIG. 7, provided in the vicinity of the opening 51a ₁ closing an opening 51a ₁ A radiation plate 51B having a shielding plate (shutter) 59 that can be used may be used. FIG. 7 is a schematic cross-sectional view showing another modification of FIG. The shielding plate 59 is connected to the moving part 60b via the connection member 60a.

The moving unit 60b is controlled by the control unit 71 of the control system 70C and moves the radiation plate 51B under the control of the control unit 71. More specifically, the moving unit 60b includes an opening position (not shown) to open the opening 51a _1, the shielding plate 59 moves between a closed position shown in FIG. 7 for closing the opening 51a _1. The movement of the shielding plate 59 is rotation around the axis in the vertical direction of the paper, translation in the vertical direction of the paper, translation in the horizontal direction of the paper, translation in the vertical direction of the paper, rotation around the axis in the vertical direction of the paper, rotation around the axis in the horizontal direction of the paper. Rotation or a combination of these may be used.

  The shielding plate 59 prevents large particles that cannot be removed by dust collection using thermophoresis, which will be described later, from adhering to the first mirror 21 when they fall from above the first mirror 21. it can.

As shown in FIG. 8, the radiation plate 51 itself may be driven. Here, FIG. 8 is a schematic cross-sectional view showing still another modification of FIG. In FIG. 8, a radiation plate 51C is used instead of the radiation plate 51 shown in FIG. 2, and a moving part 60d of the radiation plate 51C is further provided. The radiation plate 51C has a size larger than that of the radiation plate 51, and is connected to the moving part 60d via the connection member 60c. The moving unit 60d is controlled by the control unit 71 and moves the radiation plate 51C under the control of the control unit 71. More specifically, the mobile unit 60d is radiation between the open position to open the closed position for closing the opening 51a ₁ shown in FIG. 8 (a), an opening 51a ₁ shown in FIG. 8 (b) The plate 51C is moved.

  Note that the control unit 71 may move the radiation plate 51 in the Z direction via the moving unit 60d. Thereby, the distance in the Z direction of the space S shown in FIG. 2 can be adjusted.

  The wafer W is held on the wafer stage 15 by the wafer chuck 17. Reticle stage 10 and wafer stage 15 are scanned synchronously at a speed ratio proportional to the reduction magnification of projection optical system 20. The wafer stage 15 has a mechanism that moves at high speed in the X direction in the same manner as the reticle stage 10. Further, the wafer stage 15 has a fine movement mechanism in the XYZ directions and the rotation directions around the respective axes, and is configured so that the wafer W can be positioned. The position and orientation of the wafer stage 15 are controlled based on the measurement result of a laser interferometer (not shown).

  Hereinafter, the operation of the exposure apparatus 100 will be described with reference to FIGS. Here, FIG. 9 is a flowchart for explaining the operation of the exposure apparatus 100. Referring to FIG. 9, exposure apparatus 100 performs an exhaust step 1000, an exposure step 1100, and an air supply step 1200.

  Hereinafter, the exhaust step 1000 will be described in detail with reference to FIG. Here, FIG. 10 is a flowchart for explaining the details of the exhaust step 1000. When the user inputs an exhaust command (not shown), the control unit 71 instructs the exhaust devices 31 to 35 to start exhaust. As a result, exhaust of the spaces 3a to 3d is started. In the exhaust step 1000, irradiation of the EUV light L from the EUV light source is stopped.

  First, the control unit 71 acquires the measurement results of the pressure sensors 41 to 44, and determines whether the internal pressure of the spaces 3a to 3d is 10000 Pa or less at which the thermophoretic force is effective (step (hereinafter, “ Abbreviated as “S”.) 1001). In addition, since the dust collection object of the present embodiment is each mirror of the projection optical system 20 housed in the vacuum chambers 2b and 2c, the control unit 71 depends only on the measurement results of the pressure sensors 42 and 43, and the space 3b and It may be determined whether the internal pressure of 3c is 10000 Pa or less. The controller 71 repeats S1001 until it determines that the internal pressure of the spaces 3b and 3c is 10000 Pa or less.

  When the controller 71 determines that the internal pressures of the spaces 3b and 3c are 10000 Pa or less (S1001), the temperature gradient of the space between each mirror and the corresponding radiation plate becomes 10 [K / cm] or more. Is determined (S1002). Therefore, the control unit 71 acquires the measurement results of the temperature sensors 47 and 48 from the temperature measurement device 46.

  When the control unit 71 determines that the temperature gradient of the space between each mirror and the corresponding radiation plate is not 10 [K / cm] or more (S1002), it lowers the temperature of the radiation plate (S1003). In S1003, the control unit 71 controls the constant temperature circulating water tank 74 to lower the temperature of the refrigerant, or controls the Peltier element control device 76 to lower the temperature of the Peltier element. The control unit 71 repeats S1002 and S1003 until it determines that the temperature gradient of the space between each mirror and the corresponding radiation plate is 10 [K / cm] or more.

  When the controller 71 determines that the temperature gradient of the space between each mirror and the corresponding radiation plate is 10 [K / cm] or more (S1002), the internal pressure of the spaces 3a to 3d is the thermophoretic force. It is determined whether the pressure is less than 10 Pa that does not exhibit the effect (S1004). In this case, as described above, the control unit 71 may rely only on the measurement results of the pressure sensors 42 and 43 instead of all the pressure sensors 41 to 44. The controller 71 returns to S1002 if NO is determined in S1004, and proceeds to S1005 if YES is determined.

Next, the control unit 71 determines whether or not the internal pressure of the spaces 3a to 3d is a pressure of 10 ⁻³ Pa or less at which exposure may be started (S1005). When it is determined NO in S1005, the controller 71 repeats S1005, and when it is determined YES, the control unit 71 ends the exhaust (S1006).

  A step X may be further provided between S1002 and S1004 to determine whether the temperature gradient of the space between the radiation plate and the vacuum chamber is 10 [K / cm] or more. In this case, the Yes line of this step is connected to S1004, and the No line moves to the step of lowering the temperature of the radiation plate and / or the vacuum chamber 2, and then returns to Step X.

In this case, the control unit 71 can control the constant temperature circulating water tanks 74, 75, and 77, and can collect particles on the inner wall surface 2 b ₁ farther from the first mirror 21 than the radiation plate 51. Control unit 71, so that the temperature _{T 1} of the first mirror 21, the temperature _{T 2} and the temperature _{T 3} of the inner wall surface 2b ₁ of the vacuum chamber of the radiation plate _51, to satisfy the relation _{T 1>} T _2> T ₃ The temperature of the radiation plate 51 and / or the vacuum chamber 2 is lowered. Thereby, a thermophoretic force can be generated in a direction away from each mirror, and particles floating around the optical element are attracted to the wall surfaces of the spaces 3a to 3d.

  The details of the exposure step 1100 will be described below with reference to FIG. Here, FIG. 11 is a flowchart for explaining details of the exposure step 1100. First, the control unit 71 controls a robot hand (not shown) to carry the reticle R through the reticle replacement window 4a of the vacuum chamber 2a and attach it to the reticle stage 10 through the reticle chuck 12 (S1101). Next, the control unit 71 controls a robot hand (not shown) to carry the wafer W through the wafer exchange window 4b of the vacuum chamber 2d and attach it to the wafer stage 15 through the wafer chuck 17 (S1102).

  Next, the control unit 71 turns on the EUV light source and starts irradiation with the EUV light L (S1103), and starts exposure of the reticle pattern on each shot of the wafer W by the step-and-scan method (S1104). .

  Next, the control unit 71 acquires the temperature of the temperature sensor 48 for each mirror from the temperature measuring device 46, and determines whether or not the temperature of each mirror is constant at a predetermined temperature (S1105). The predetermined temperature is between 20 ° C. and 25 ° C., preferably 22 ° C. to 24 ° C. The temperature of each mirror gradually increases by absorbing EUV light. When determining that the temperature of each mirror is higher than 23 ° (S1105), the control unit 71 decreases the temperature of the radiation plate (S1106). In S1106, the control unit 71 controls the constant temperature circulating water tank 74 to lower the temperature of the refrigerant, or controls the Peltier element control device 76 to lower the temperature of the Peltier element.

  Thus, the temperature of the radiation plate is controlled so that the temperature of each mirror is kept constant during exposure. Accordingly, it is possible to suppress the heat generation of each mirror due to the irradiation with the EUV light L during exposure, and it is possible to suppress the deterioration of the optical performance due to thermal strain. In this case, as described with reference to FIG. 8, the control unit 71 may move the radiation plate 51 in the Z direction so as to approach the mirror 21 via the moving unit 60 d. As a result, the distance in the Z direction of the space S shown in FIG. 2 can be reduced to increase the heat dissipation efficiency.

  When the controller 71 determines that the temperature of each mirror is constant at 23 ° (S1105), it determines whether or not exposure of all shots on the wafer W has been completed (S1107). If the controller 71 determines that exposure of all shots on the wafer W has not been completed, the controller 71 steps the wafer stage 15 in the XY directions and moves it to the next scanning exposure start position. Subsequently, the reticle stage 10 and the wafer stage 15 are again synchronously scanned in the X direction at a speed ratio proportional to the reduction magnification of the projection optical system 20. In this manner, the operation of synchronously scanning the reduced projection image of the reticle R on the wafer W is repeated (step-and-scan). Thus, the reticle pattern is transferred to the entire surface of the wafer W.

  When the controller 71 determines whether exposure of all shots on the wafer W has been completed (S1107), the controller 71 determines whether there is a next wafer to be exposed (S1108). When the control unit 71 determines whether there is a next wafer to be exposed (S1108), the control unit 71 unloads the current wafer W and loads the next wafer W (S1109). Thereafter, the process returns to S1104.

  On the other hand, when determining that there is no next wafer to be exposed (S1108), the control unit 71 unloads the current wafer W (S1110). Thereafter, the control unit 71 turns off the EUV light source (S1111), and unloads the reticle R (S1112).

  The control unit 71 also performs pressure control necessary for exposure. For example, the control unit 71 acquires the measurement results of the pressure sensors 41 to 44 and controls the exhaust devices 32 to 34 so that the pressure in the first optical path space 3b is higher than the pressure in the second optical path space 3c.

  Hereinafter, the details of the air supply step 1200 will be described with reference to FIG. Here, FIG. 12 is a flowchart for explaining the details of the air supply step 1200 (control at the time of air supply). When the user inputs an air supply command (not shown), the control unit 71 instructs the exhaust devices 31 to 35 to start air supply. As a result, air supply to the spaces 3a to 3d is started. In the air supply step 1200, the irradiation of the EUV light L from the EUV light source is stopped.

First, the control unit 71 acquires the measurement results of the pressure sensors 41 to 44, and determines whether the internal pressure of the spaces 3a to 3d is equal to or less than 10 ⁻³ Pa (S1201). When the control unit 71 determines NO in S1201, the control unit 71 repeats S1201.

When the control unit 71 determines that the internal pressure of the spaces 3a to 3d is a pressure of 10 ⁻³ Pa or less (S1201), the temperature gradient of the space between each mirror and the corresponding radiation plate is 10 [K / cm]] or more is determined (S1202).

  When it is determined that the temperature gradient of the space between each mirror and the corresponding radiation plate is not 10 [K / cm] or more (S1202), the control unit 71 lowers the temperature of the radiation plate (S1203). In S1203, the control unit 71 controls the constant temperature circulating water tank 74 to lower the temperature of the refrigerant, or controls the Peltier element control device 76 to lower the temperature of the Peltier element. The control unit 71 repeats S1202 and S1203 until it determines that the temperature gradient in the space between each mirror and the corresponding radiation plate is 10 [K / cm] or more.

  When it is determined that the temperature gradient is 10 [K / cm] or more (S1202), the control unit 71 acquires the measurement results of the pressure sensors 41 to 44, and whether the internal pressures of the spaces 3a to 3d are 10000 Pa or less. Is determined (S1204). When the control unit 71 determines that the internal pressures of the spaces 3b and 3c are not 10,000 Pa or less, the control unit 71 returns to S1202.

On the other hand, when the control unit 71 determines that the internal pressures of the spaces 3b and 3c are equal to or lower than 10,000 Pa, the control unit 71 determines whether the internal pressures of the spaces 3a to 3d are equal to or higher than 10 ⁵ Pa, which is the atmospheric pressure (S1205). When the control unit 71 determines that the internal pressure of the spaces 3a to 3d is equal to or higher than 10 ⁵ Pa (S1205), the exhaust process is terminated (S1206).

  As shown in S1003, S1106, and S1203, in this embodiment, the radiation plate used for heat dissipation of the optical element at the time of exposure is used as a dust collecting unit that reduces or prevents particles from adhering to the optical element at the time of air supply and exhaust. To do. Conventionally, the radiation plate provided in the exposure apparatus 100 is made multifunctional by providing the dust collecting unit function, thereby preventing a new dust collecting unit from being provided in the vacuum chamber 2 that is required to be downsized. .

Hereinafter, a pressure region where the exposure apparatus 100 performs exposure, a pressure region where dust collection is performed, and a pressure region of air supply / exhaust will be described with reference to FIG. Here, FIG. 13 is a graph showing the relationship between pressure and temperature. In FIG. 13, the horizontal axis is pressure, and the pressure increases from the right side to the left side. The vertical axis is temperature. The pressure area of the air supply / exhaust of the exposure apparatus 100 is the (A + B) area, and the pressure area used for dust collection is the A area. The pressure in the A region corresponds to 10 Pa to 10000 Pa. The pressure region where the exposure apparatus 100 performs exposure is the C region, which corresponds to 10 ⁻³ Pa to 10 ⁻⁷ Pa.

First, the reason why the pressure region used for dust collection is set to the A region will be described with reference to FIG. FIG. 14 is a graph showing the thermophoretic force and gravity acting on the fluorine fine particles when the temperature gradient in the space between the optical element (mirror) and the radiation plate is 10 [K / cm]. In FIG. 14, the vertical axis represents force [m / s ² ] and the horizontal axis represents pressure [Pa]. The principle of thermophoretic force is that when there is a temperature gradient in the gas surrounding the particle, the particle is given a larger kinetic energy than the gas molecule on the cold side, and the particle is transferred from the object on the hot side to the cold side. To move to. The thermophoretic force Fx is given by the following Talbot equation described in Non-Patent Document 1. The thermophoretic force curve can be obtained by taking into account the temperature jump between the gas temperature and the solid temperature in Equation 1 below. This is because the thermophoretic force acting on the microparticles at a pressure in the range of 10 Pa to 10000 Pa is the maximum or 98% of the maximum value from FIG.

However, Formula 1 assumes that the particles are spherical and the fluid is an ideal gas. Here, Dp is the particle diameter, T is the gas temperature, μ is the viscosity coefficient, ρ is the gas density, Kn is the Knudsen number 2λ / Dp, and λ is the mean free path of the gas η / {0.499P (8M / πRT ^1/2 }, M is the molecular weight, R is the gas constant, and K is k / kp. Further, k is the thermal conductivity of the gas only by the energy of parallel movement, kp is the thermal conductivity of the particle, Cs is 1.17, Ct = 2.18, Cm = 1.14, and ΔT / Δx is the temperature gradient. .

FIG. 15 is a graph showing the velocity of fluorine fine particles having a diameter of 0.1 to 1.5 μm floating in the vicinity of the optical element in the vacuum chamber 2, the vertical axis represents the velocity of the fine particles [m / s], and the horizontal axis represents the velocity. The pressure in the vacuum chamber 2 [Pa]. The speed is expressed with the direction of gravity as positive. Further, the velocity V ₁ of the fine particles floating near the optical element surface is indicated by a solid line, and the velocity V ₂ of the fine particles floating near the rear surface of the optical element is indicated by a one-dot chain line. The velocity of fine particles floating near the surface can be expressed by the following equation.

  The thermophoretic velocity can be expressed by the following equation.

Here, the thermophoretic coefficient _Kth is given by the following equation.

  ν is the kinematic viscosity of the gas, α is the specific heat ratio, and is given by the gas heat conduction ratio / particle heat conduction ratio. The average deposition rate on the optical element in a laminar flow field is given by:

Here, D is a diffusion coefficient and is given by C _C kT / (3πμD _p ). L is the diameter of the optical element, u ₀ is the average velocity of the air current in sufficient distance away from the optical element, S _c is given by [nu / D Schmitt number. k is the Boltzmann factor, _{v g} is the gravitational settling velocity ^{_{= D p 2 ρ p gC C}} / (18μ), ρ p is the density of particles, g is the gravitational acceleration, _{C C} is ₁ + K n by the correction factor of Cunningham [1.25 + 0 .4exp (−1.1 / K _n )].

  Expressions 2 to 4 are disclosed in Non-Patent Document 2.

  In this embodiment, the temperature and position of the radiation plate are controlled so that the temperature gradient of the space becomes 10 K / cm or more. The controller 71 controls the temperature of the radiation plate so that the temperature of the radiation plate is lower than the temperature of the optical element in the region A of FIG. Thereby, particles rolled up at the time of air supply / exhaust are attracted from the optical element to the radiation plate side by thermophoresis, and the adhesion of particles to the optical element can be reduced, and the optical performance of the optical element can be maintained.

  More specifically, the control unit 71 controls the temperature and position of the radiation plate so that the temperature gradient in the space between the optical element and the radiation plate is 10 K / cm or more. Such control is performed in S1002 and S1003 shown in FIG. 10, and in S1202 and S1203 shown in FIG.

  In the dust collection step, it is sufficient to form a temperature gradient of 10 K / cm or more while maintaining a pressure in the range of 10 Pa or more and 10,000 Pa or less for 10 seconds or more and 600 seconds or less. The reason for “10 seconds or longer” is that it is the shortest time required for moving fluorine fine particles having a diameter of 1.5 μm, which is a size close to the maximum among particles in which 10 seconds can exist, to the radiation plate. . The condition at this time is that the distance between the optical element and the radiation plate is 0.2 cm, and the temperature gradient of the space between them is 10 [K / cm]. The reason why “600 seconds or less” is set is that 600 seconds is the longest time required for the fluorine fine particles having a diameter of 1.5 μm to move to the radiation plate. The condition at this time is that the distance between the optical element and the radiation plate is 1.0 cm, and the temperature gradient of the space between the two is 100 [K / cm].

  The controller 71 secures a pressure in the range of 10 Pa or more and 10,000 Pa or less in the exhausting step 1000 by S1001 and S1004. Moreover, the control part 71 ensures the pressure of the range of 10 Pa or more and 10000 Pa or less in the air supply step 1000 by S1201 and S1204.

  In addition, the control unit 71 ensures that a temperature gradient of 10 K / cm or more is maintained for a period of 10 seconds or more and 600 seconds or less in S1003 and S1203. In that case, the control unit 71 can use the timer 73.

  By performing air supply / exhaust as described above, particles wound up by air supply / exhaust are attracted from the optical element to the radiation plate by thermophoresis, thereby reducing the adhesion of particles to the optical element and maintaining its optical performance. be able to.

  Next, a device manufacturing method using the exposure apparatus 100 will be described with reference to FIGS. Here, FIG. 16 is a flowchart for explaining the manufacture of devices (semiconductor chips such as IC and LSI, LCDs, CCDs, etc.). In the present embodiment, the manufacture of a semiconductor chip will be described as an example.

  In step 1 (circuit design), a device circuit is designed. In step 2 (mask production), a reticle R on which the designed circuit pattern is formed is produced. In step 3 (wafer manufacture), a wafer W is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer W by lithography using the reticle R and the wafer W. Step 5 (assembly) is referred to as a post-process, and is a process for forming a semiconductor chip using the wafer W manufactured in step 4, and includes an assembly process (dicing, bonding), a packaging process (chip encapsulation), and the like. including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

  FIG. 17 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer W is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer W. In step 13 (electrode formation), an electrode is formed on the wafer W by vapor deposition or the like. In step 14 (ion implantation), ions are implanted into the wafer W. In step 15 (resist process), a resist is applied to the wafer W. Step 16 (exposure) uses the exposure apparatus 100 to expose a reticle pattern onto the wafer. In step 17 (development), the exposed wafer W is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed.

  By repeatedly performing these steps, multiple circuit patterns are formed on the wafer. According to the device manufacturing method of the present embodiment, since exposure can be performed in a state where particles are removed from the optical element, it is possible to manufacture a device with higher quality than before. Thus, the device manufacturing method using the exposure apparatus and the resulting device also constitute one aspect of the present invention.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

It is a schematic block diagram of the exposure apparatus of one Example of this invention. FIG. 2 is a schematic partial enlarged cross-sectional view of a projection optical system of the exposure apparatus shown in FIG. It is a schematic sectional drawing of the modification of FIG. It is a schematic sectional drawing of the modification of FIG. It is a schematic sectional drawing of the modification of the exposure apparatus shown in FIG. It is a schematic sectional drawing which shows the modification of FIG. It is a schematic sectional drawing which shows another modification of FIG. 8 (a) and 8 (b) are schematic cross-sectional views showing a modification of the movement of the radiation plate shown in FIG. 2 is a flowchart for explaining the operation of the exposure apparatus shown in FIG. It is a flowchart for demonstrating the detail of step 1000 shown in FIG. It is a flowchart for demonstrating the detail of step 1100 shown in FIG. It is a flowchart for demonstrating the detail of step 1200 shown in FIG. It is a graph which shows the pressure area | region used for air supply / exhaust of this example, exposure, and dust collection. It is the graph which showed the thermophoretic force which acts on the fluorine fine particle which floats in a vacuum chamber. It is the graph which showed the relationship between the moving speed of a fluorine fine particle, and a pressure. It is a flowchart for demonstrating the device manufacturing method using the exposure apparatus shown in FIG. It is a detailed flowchart of step 4 shown in FIG.

Explanation of symbols

R Original (reticle)
W substrate (wafer)
2, 2a-2d Vacuum chamber 21-26 Optical element (mirror)
41-44 Temperature measurement unit (pressure sensor)
46, 47 First temperature measurement unit (temperature sensor)
46, 48 Second temperature measurement unit (temperature sensor)
46, 49 Third temperature measurement unit (temperature sensor)
51a ₁ opening 51-56 radiation plate 51A radiation plate (mesh plate)
58 Mesh 59 Shield plate (shutter)
60b, 60d Moving unit 65 Optical element heating unit 66 Vacuum chamber cooling unit (pipe)
71 Control unit 100, 100A Exposure apparatus

Claims (10)

In an exposure apparatus that exposes a substrate pattern to a substrate in a vacuum environment,
A vacuum chamber for maintaining the optical path in a vacuum;
An optical element disposed in the vacuum chamber;
A first temperature measuring unit for measuring the temperature of the optical element;
A radiation plate capable of controlling the temperature of the optical element by radiation;
A second temperature measuring unit for measuring the temperature of the radiation plate;
A control unit that acquires measurement results by the first and second temperature measurement units and controls the temperature of the radiation plate;
The controller controls the radiation so that the temperature of the radiation element is lower than the temperature of the optical element when the vacuum chamber is exhausted or supplied so that the temperature of the optical element is constant during exposure. An exposure apparatus for controlling a temperature of a plate. A pressure measuring unit for measuring the pressure in the vacuum chamber;
The controller controls the temperature gradient of the space between the radiation plate and the optical element during a period of 10 seconds to 600 seconds at a pressure in a range of 10 Pa to 10000 Pa at the time of exhausting or supplying the vacuum chamber. The exposure apparatus according to claim 1, wherein the temperature of the radiation plate is controlled so as to have 10 K / cm or more.   3. The exposure apparatus according to claim 1, further comprising an optical element heating unit that is controlled by the control unit and that heats the optical element during the exhaust or the supply of air. The exposure apparatus includes:
A vacuum chamber cooling section for cooling the wall surface in the vacuum chamber;
A third temperature measurement unit for measuring the temperature of the wall surface of the vacuum chamber;
The control unit obtains measurement results by the second and third temperature measurement units, and a temperature gradient of a space between the wall surface in the vacuum chamber and the radiation plate is 10 K / at the time of exhaust or supply. 4. The cooling unit is controlled according to claim 1, wherein the cooling unit is controlled such that the temperature of the wall surface in the vacuum chamber is lower than the temperature of the radiation plate. Exposure equipment. A shielding plate capable of opening and closing the opening of the radiation plate disposed in the optical path;
A moving unit that is controlled by the control unit and moves the shielding plate between an opening position that opens the opening and a closing position that closes the opening;
The control unit opens the opening of the radiation plate during the exposure via the shielding plate and the moving unit, and closes the opening of the radiation plate during the exhaust or the supply of air. The exposure apparatus according to any one of claims 1 to 4.   5. The apparatus according to claim 1, further comprising a moving unit that is controlled by the control unit and moves the radiation plate with respect to the optical element during the exhaust or the supply of air. Exposure equipment. The radiation plate has an opening that can be disposed in the optical path;
The moving unit moves the radiation plate between an opening position that opens the opening and a closing position that closes the opening,
The said control part opens the said opening part at the time of the said exposure via the said radiation plate and the said moving part, and closes the said opening part at the time of the said exhaust_gas | exhaustion or the said air_supply. Exposure device.   The exposure apparatus according to claim 1, wherein the radiation plate is a mesh plate having a mesh. Exposing the substrate using the exposure apparatus according to any one of claims 1 to 8,
And a step of developing the exposed substrate. In a method of replacing the atmosphere of a vacuum chamber of an exposure apparatus that exposes a substrate in a vacuum environment using light from a light source by exhaust or supply air,
At a pressure in the range of 10 Pa to 10000 Pa, the temperature gradient in the space between the radiation plate disposed in the vacuum chamber and the optical element disposed in the vacuum chamber is 10 K / cm only for a period of 10 seconds to 600 seconds. And a method of controlling the temperature of the radiation plate so that the temperature of the radiation plate is lower than the temperature of the optical element.