JP4474979B2 - Stage apparatus and exposure apparatus - Google Patents

Description

  The present invention relates to a stage apparatus and an exposure apparatus, and more particularly to a stage apparatus and an exposure apparatus suitable for use when exposing a substrate on a stage via a projection optical system and a liquid.

Semiconductor devices and liquid crystal display devices are manufactured by a so-called photolithography technique in which a pattern formed on a mask is transferred onto a photosensitive substrate. An exposure apparatus used in this photolithography process has a mask stage for supporting a mask and a substrate stage for supporting a substrate, and a mask pattern is transferred via a projection optical system while sequentially moving the mask stage and the substrate stage. It is transferred to the substrate. In recent years, in order to cope with higher integration of device patterns, higher resolution of the projection optical system is desired. The resolution of the projection optical system becomes higher as the exposure wavelength used is shorter and the numerical aperture of the projection optical system is larger. Therefore, the exposure wavelength used in the exposure apparatus is shortened year by year, and the numerical aperture of the projection optical system is also increasing. The mainstream exposure wavelength is 248 nm of the KrF excimer laser, but the 193 nm of the shorter wavelength ArF excimer laser is also being put into practical use. Also, when performing exposure, the depth of focus (DOF) is important as well as the resolution. The resolution R and the depth of focus δ are each expressed by the following equations.
R = k1 · λ / NA (1)
δ = ± k2 · λ / NA ² (2)
Here, λ is the exposure wavelength, NA is the numerical aperture of the projection optical system, and k1 and k2 are process coefficients. From the equations (1) and (2), it can be seen that the depth of focus δ becomes narrower when the exposure wavelength λ is shortened and the numerical aperture NA is increased in order to increase the resolution R.

If the depth of focus δ becomes too narrow, it becomes difficult to match the substrate surface with the image plane of the projection optical system, and the focus margin during the exposure operation may be insufficient. Therefore, as a method for substantially shortening the exposure wavelength and increasing the depth of focus, for example, a liquid immersion method disclosed in Patent Document 1 below has been proposed. In this immersion method, a space between the lower surface of the projection optical system and the substrate surface is filled with a liquid such as water or an organic solvent to form an immersion region, and the wavelength of exposure light in the liquid is 1 / n of that in air. (Where n is the refractive index of the liquid, which is usually about 1.2 to 1.6), the resolution is improved, and the depth of focus is expanded about n times.
In this immersion exposure, the liquid supply member and liquid recovery member for forming the immersion area and the substrate surface (substrate holder) are arranged with a gap, and the liquid leaks from these gaps due to the surface tension of the liquid. To prevent you from doing.
International Publication No. 99/49504 Pamphlet

In the above exposure apparatus, the surface of the substrate is adjusted to the image plane of the projection optical system by the autofocus method and the auto leveling method by controlling the focus position and the tilt angle (attitude) of the substrate. That is, by driving the stage that holds the substrate, the position of the substrate (focus position) in the optical axis direction of the exposure light and the position of the substrate in a direction substantially parallel to the image plane of the projection optical system are adjusted. .
However, if the substrate stage (substrate holder) is tilted for controlling the posture of the substrate, the size of the gap between the liquid supply member or the liquid recovery member and the substrate changes, so that liquid can be supplied from the enlarged gap, for example. There is a possibility that the liquid immersion area cannot be formed stably, such as leakage.

  The present invention has been made in consideration of the above points, and an object of the present invention is to provide a stage apparatus and an exposure apparatus that can stably form an immersion area even when the position / attitude control of a substrate is performed. And

In order to achieve the above object, the present invention adopts the following configuration corresponding to FIGS. 1 to 6 showing the embodiment.
The stage apparatus of the present invention is a stage apparatus (PST) having a mounting surface (34A) on which a substrate (P) is mounted, and is a liquid that faces the substrate (P) and is supplied to the substrate (P). A moving device (70) that moves in a direction crossing the placement surface (34A) according to the pressure of (1) is provided.

  Therefore, in the stage apparatus of the present invention, when the placement surface (34A) moves in the direction approaching the moving device (70) during the position control and posture control of the substrate (P), the substrate (P) and the moving device ( 70), the moving device (70) moves away from the substrate (P), and the mounting surface (34A) moves away from the moving device (70). Then, since the pressure of the liquid between a board | substrate (P) and a moving apparatus (70) reduces, the moving apparatus (70) moves to the direction approaching a board | substrate (P). Therefore, the gap (G) between the moving device (70) and the substrate (P) can be maintained constant, and a liquid region (immersion region) is stably formed on the substrate (P). be able to.

  The exposure apparatus of the present invention is an exposure apparatus that exposes a pattern to a substrate (P) placed on a stage apparatus (PST). The stage apparatus (PST) according to any one of claims 1 to 8. It is characterized by using.

Therefore, in the exposure apparatus of the present invention, it becomes possible to expose the pattern onto the substrate through the stably formed liquid region (AR2) even after performing the focus adjustment and the attitude control. An exposure process with a large focus margin and improved resolution can be realized.
In order to explain the present invention in an easy-to-understand manner, the description has been made in association with the reference numerals of the drawings showing one embodiment, but it goes without saying that the present invention is not limited to the embodiment.

  In the present invention, the immersion region can be stably formed, and when applied to an exposure apparatus, stable immersion exposure is possible, the exposure margin is large during the exposure operation, and the exposure processing is improved in resolution. Can be realized.

Embodiments of the stage apparatus and exposure apparatus of the present invention will be described below with reference to FIGS.
FIG. 1 is a schematic block diagram showing an embodiment of the exposure apparatus of the present invention.
In FIG. 1, an exposure apparatus EX illuminates a mask stage MST for supporting a mask M, a substrate stage PST for supporting a substrate (photosensitive substrate) P, and a mask M supported by the mask stage MST with exposure light EL. The operation of the illumination optical system IL, the projection optical system PL that projects and exposes the pattern image of the mask M illuminated by the exposure light EL onto the substrate P supported by the substrate stage PST as the stage device, and the operation of the exposure apparatus EX as a whole. And a control device CONT for overall control.

  The exposure apparatus EX of the present embodiment is an immersion exposure apparatus to which an immersion method is applied in order to improve the resolution by substantially shortening the exposure wavelength and substantially increase the depth of focus. A liquid supply mechanism 10 for supplying the liquid 1 to the substrate P, and a liquid recovery mechanism 20 for recovering the liquid 1 on the substrate P. In the present embodiment, pure water is used as the liquid 1. The exposure apparatus EX transfers at least a part of the substrate P including the projection area AR1 of the projection optical system PL by the liquid 1 supplied from the liquid supply mechanism 10 while at least transferring the pattern image of the mask M onto the substrate P. The liquid immersion area AR2 is formed (locally). Specifically, the exposure apparatus EX fills the liquid 1 between the tip of the projection optical system PL and the surface (exposure surface) of the substrate P, and the liquid 1 between the projection optical system PL and the substrate P and A pattern image of the mask M is projected onto the substrate P via the projection optical system PL, and the substrate P is exposed.

  Here, in this embodiment, since an inverted system is used as the projection optical system PL, the mask M and the substrate P as the exposure apparatus EX are moved to the mask M while synchronously moving in different directions (reverse directions) in the scanning direction. A case where a scanning exposure apparatus (so-called scanning stepper) that exposes the formed pattern onto the substrate P is used will be described as an example. In the following description, the direction that coincides with the optical axis AX of the projection optical system PL is the Z-axis direction, the synchronous movement direction (scanning direction) between the mask M and the substrate P in the plane perpendicular to the Z-axis direction is the X-axis direction, A direction (non-scanning direction) perpendicular to the Z-axis direction and the Y-axis direction is defined as a Y-axis direction. In addition, the rotation (inclination) directions around the X axis, the Y axis, and the Z axis are the θX, θY, and θZ directions, respectively. Here, the “substrate” includes a semiconductor wafer coated with a photoresist, which is a photosensitive material, and the “mask” includes a reticle on which a device pattern to be reduced and projected on the substrate is formed.

  The illumination optical system IL illuminates the mask M supported by the mask stage MST with the exposure light EL. From the exposure light source, the optical integrator that equalizes the illuminance of the light beam emitted from the exposure light source, and the optical integrator. A condenser lens for condensing the exposure light EL, a relay lens system, a variable field stop for setting the illumination area on the mask M by the exposure light EL in a slit shape, and the like. A predetermined illumination area on the mask M is illuminated with the exposure light EL having a uniform illuminance distribution by the illumination optical system IL. As the exposure light EL emitted from the illumination optical system IL, for example, far ultraviolet light (g-line, h-line, i-line) and KrF excimer laser light (wavelength 248 nm) emitted from a mercury lamp (e.g. DUV light), vacuum ultraviolet light (VUV light) such as ArF excimer laser light (wavelength 193 nm) and F2 laser light (wavelength 157 nm), or the like is used. In this embodiment, ArF excimer laser light is used. As described above, the liquid 1 in this embodiment is pure water, and can be transmitted even if the exposure light EL is ArF excimer laser light. Further, pure water can transmit ultraviolet rays (g-rays, h-rays, i-rays) and far-ultraviolet light (DUV light) such as KrF excimer laser light (wavelength 248 nm).

  The mask stage MST supports the mask M, and can move two-dimensionally in a plane perpendicular to the optical axis AX of the projection optical system PL, that is, in the XY plane, and can be slightly rotated in the θZ direction. The mask stage MST is driven by a mask stage driving device MSTD such as a linear motor. The mask stage driving device MSTD is controlled by the control device CONT. A movable mirror 50 is provided on the mask stage MST. A laser interferometer 51 is provided at a position facing the moving mirror 50. The two-dimensional position and rotation angle of the mask M on the mask stage MST are measured in real time by the laser interferometer 51, and the measurement result is output to the control device CONT. The control device CONT drives the mask stage driving device MSTD based on the measurement result of the laser interferometer 51, thereby positioning the mask M supported by the mask stage MST.

  The projection optical system PL projects and exposes the pattern of the mask M onto the substrate P at a predetermined projection magnification β, and includes a plurality of optical elements including an optical element (lens) 2 provided at the front end portion on the substrate P side. These optical elements are supported by a lens barrel PK. In the present embodiment, the projection optical system PL is a reduction system having a projection magnification β of, for example, 1/4 or 1/5. Note that the projection optical system PL may be either an equal magnification system or an enlargement system. The optical element 2 at the tip of the projection optical system PL of the present embodiment is detachably (replaceable) with respect to the lens barrel PK, and the liquid 1 in the liquid immersion area AR2 comes into contact with the optical element 2. .

  The optical element 2 is made of meteorite. Since meteorite has high affinity with water, the liquid 1 can be brought into close contact with almost the entire liquid contact surface 2a of the optical element 2. That is, in this embodiment, since the liquid (water) 1 having high affinity with the liquid contact surface 2a of the optical element 2 is supplied, the adhesion between the liquid contact surface 2a of the optical element 2 and the liquid 1 is set. The optical path between the optical element 2 and the substrate P can be reliably filled with the liquid 1. The optical element 2 may be quartz having a high affinity with water. Further, the liquid contact surface 2a of the optical element 2 may be subjected to a hydrophilization (lyophilic treatment) to further increase the affinity with the liquid 1. Further, since the vicinity of the tip of the lens barrel PK is in contact with the liquid (water) 1, at least the vicinity of the tip is formed of a metal resistant to rust such as Ti (titanium).

  As shown in FIG. 2, a partition PK1 that supports the optical element 2 and an end wall PK3 that forms a space 71 in cooperation with the partition PK1 and the side wall PK2 are provided at the lower end of the lens barrel PK. . A supply pipe 12A of a liquid supply mechanism 10 that supplies a liquid to the space 71 is connected to the side wall PK2, which will be described later.

  A through hole 72 through which the exposure light EL passes is formed in the end wall PK3, and a focus detection system AF is provided in the vicinity of the through hole 72. The focus detection system AF receives the reflected light of the projection light beam AF1 that projects the detection light beam B from the oblique direction through the liquid 1 on the substrate P (surface PA) and the reflected light of the detection light beam B reflected by the substrate P. And a light receiving portion AF2. The light reception result of the focus detection system AF (light receiving unit AF2) is output to the control device CONT. The control device CONT can detect the position information of the substrate P surface PA in the Z-axis direction based on the detection result of the focus detection system AF. Further, it is possible to detect inclination information of the substrate P in the θX and θY directions by projecting a plurality of detection light beams from the light projecting portion AF1.

  Further, a moving device 70 constituting a part of the substrate stage PST is supported on the end wall PK3 of the barrel PK so as to face the substrate P. The moving device 70 forms an immersion area AR2 and moves in a direction intersecting the surface PA of the substrate P. The moving device 70 is flexible to the support member 73 provided on the lower surface of the end wall PK3 and the support member 73. And a pad portion 75 suspended through a bellows tube (flexible portion) 74 having a main body.

  The support member 73 is formed in a substantially ring shape surrounding the through hole 72 of the end wall PK3 and the autofocus system AF, and the upper end of the bellows tube 74 is supported at the inner peripheral side end. The support member 73 is provided with an electromagnetic actuator (elevating device) 76 that elevates and lowers the pad portion 75. The electromagnetic actuator 76 includes a core body 77 made of a magnetic body projecting toward the substrate P on the outer peripheral side of the support member 73, and a coil body 78 wound around the core body 77. Whether or not the coil body 78 is energized is controlled by the control device CONT.

  The pad portion 75 is formed of a lyophilic ceramic material. As shown in FIG. 3A, the inner peripheral surface 75a formed with a larger diameter than the through hole 72 of the end wall PK3, and this An inclined portion 75b in which the distance between the substrate P and the pad portion 75 decreases toward the periphery of the substrate P with the inner peripheral surface 75a as a base point, and an absorption of a rectangular cross section that is located on the outer peripheral side and opens toward the surface PA of the substrate P. And a liquid groove 75c. A recovery pipe 21A of the liquid recovery mechanism 20 is connected to the liquid absorption groove 75c, which will be described later.

  Further, the pad portion 75 is provided with an attracting portion 79 formed of a magnetic material such as a steel material and extending to the outer peripheral side at a position facing the magnet generator 77 and the coil body 78. Therefore, the electromagnetic actuator 76 functions as an electromagnet when the coil body 78 is energized under the control of the control device CONT, and the pad portion 75 is raised by attracting the attracting portion 79. On the other hand, by stopping energization of the coil body 78, the electromagnetic actuator 76 does not function as an electromagnet, and the pad portion 75 is lowered by its own weight.

  Returning to FIG. 1, the liquid supply mechanism 10 supplies a predetermined liquid 1 onto the substrate P, and includes a tank that stores the liquid 1, a liquid supply unit 12 that includes a pressure pump, and the like. The liquid 1 is supplied onto the substrate P through the supply pipe 12A and the space 71 of the lens barrel PK. Further, the liquid supply operation of the liquid supply unit 12 (for example, the liquid supply amount per unit time on the substrate P) is controlled by the control device CONT. Further, the liquid supply unit 12 has a liquid temperature adjusting mechanism, and supplies the liquid 1 having substantially the same temperature (for example, 23 ° C.) as the temperature in the chamber in which the apparatus is accommodated onto the substrate P. Yes.

  The liquid recovery mechanism 20 recovers the liquid 1 on the substrate P, and includes a liquid recovery unit (liquid absorbing device) 21 connected via a recovery tube 21A. The liquid recovery unit 21 includes, for example, a vacuum system (suction device) such as a vacuum pump, a gas-liquid separator, a tank for storing the recovered liquid 1, and the liquid 1 on the substrate P is absorbed by the pad unit 75. Recovery is performed via the groove 75c and the recovery tube 21A. The liquid recovery operation (for example, the liquid recovery amount per unit time) of the liquid recovery unit 21 is controlled by the control device CONT.

  The substrate stage PST supports the substrate P, and supports a substrate table 52 that holds the substrate P via a substrate holder (holder) PH, an XY stage 53 that supports the substrate table 52, and an XY stage 53. And a base 54. The substrate stage PST is driven by a substrate stage driving device PSTD such as a linear motor. The substrate stage driving device PSTD is controlled by the control device CONT. By driving the substrate table 52, the position (focus position) in the Z-axis direction and the position in the θX and θY directions of the substrate P held by the substrate table are controlled. Further, by driving the XY stage 53, the position of the substrate P in the XY direction (position in a direction substantially parallel to the image plane of the projection optical system PL) is controlled. That is, the substrate table 52 is a Z stage (driving device) that controls the focus position and tilt angle of the substrate P to align the surface of the substrate P with the image plane of the projection optical system PL by the autofocus method and the autoleveling method. The XY stage 53 positions the substrate P in the X-axis direction and the Y-axis direction.

  A movable mirror 55 is provided on the substrate stage PST (substrate table 52). A laser interferometer 56 is provided at a position facing the movable mirror 55. The two-dimensional position and rotation angle of the substrate P on the substrate stage PST are measured in real time by the laser interferometer 56, and the measurement result is output to the control device CONT. The controller CONT positions the substrate P supported by the substrate stage PST by driving the substrate stage drive device PSTD based on the measurement result of the laser interferometer 56.

  In the vicinity of the substrate table 52, a substrate alignment system 350 for detecting an alignment mark on the substrate P or a reference mark (not shown) provided on the substrate table 52 is disposed. A mask alignment system 360 for detecting a reference mark on the substrate table 52 is provided near the mask stage MST via the mask M and the projection optical system PL. As the configuration of the substrate alignment system 350, the one disclosed in JP-A-4-65603 can be used, and the configuration of the mask alignment system 360 is disclosed in JP-A-7-176468. Can be used.

FIG. 4 is an enlarged cross-sectional view of a main part of the substrate table 52 holding the substrate P.
As shown in this figure, the substrate holder PH constituting a part of the substrate table 52 is disposed inside the recess 31 of the substrate table 52.
A plate member 32 having a flat surface 32 </ b> A that is substantially the same height (level) as the surface of the substrate P is provided around the recess 31. The plate member 32 is disposed so as to surround the substrate holder PH (substrate P). The plate member 32 is formed of a material having liquid repellency such as polytetrafluoroethylene (Teflon (registered trademark)). Since the plate member 32 having the flat surface 32A substantially flush with the surface of the substrate P is provided around the substrate P, the image plane side of the projection optical system PL can be used even when the edge region E of the substrate P is subjected to immersion exposure. The liquid immersion area AR2 can be formed satisfactorily.

The substrate holder PH is disposed between the support portion 34 and a plurality of support portions 34 that are provided on the substantially annular peripheral wall portion 33 and the base portion 35 inside the peripheral wall portion 33 and support the substrate P. And a plurality of suction ports 41 for sucking and holding the substrate P. The support portion 34 and the suction port 41 are uniformly arranged inside the peripheral wall portion 33.
The peripheral wall portion 33 and the support portion 34 are provided on a substantially disc-shaped base portion 35 that constitutes a part of the substrate holder PH. Each of the support portions 34 has a trapezoidal shape in cross section, and the substrate P is held and placed on the upper end surfaces (mounting surfaces) 34A of the plurality of support portions 34 that are holding surfaces.
In the figure, the upper end surface of the peripheral wall portion 33 has a relatively wide width, but actually has only a width of about 1 to 2 mm.

  An upper surface 33A of the peripheral wall 33 is a flat surface. The height of the peripheral wall portion 33 is lower than the height of the support portion 34 (upper end surface 34 </ b> A), and a gap B is formed between the substrate P and the peripheral wall portion 33. The gap B is smaller than the gap A between the inner side surface 36 of the recess 31 and the side surface PB of the substrate P. A gap C is formed between the inner side surface 36 of the recess 31 and the side surface 37 of the substrate holder PH facing the inner side surface 36. Here, the diameter of the substrate holder PH is smaller than the diameter of the substrate P, and the gap A is smaller than the gap C. In this embodiment, the substrate P is not formed with a notch (orientation flat, notch, etc.) for alignment, the substrate P is substantially circular, and the gap A is 0.1 mm over the entire circumference. Since it is about 1.0 mm in this embodiment and about 0.3 mm, inflow of liquid can be prevented. In addition, when the notch part is formed in the board | substrate P, the shape according to the notch part of the plate member 32 or the surrounding wall part 33 is provided, such as providing a projection part in the plate member 32 or the surrounding wall part 33 according to the notch part. You can do it. By doing so, the gap A can be secured between the substrate P and the plate member 32 even in the cutout portion of the substrate P.

Photoresist (photosensitive material) 90 is applied to the surface PA, which is the exposure surface of the substrate P. In this embodiment, the photosensitive material 90 is a photosensitive material for ArF excimer laser (for example, TARF-P6100 manufactured by Tokyo Ohka Kogyo Co., Ltd.) and has liquid repellency (water repellency), and its contact angle is 70. It is about ~ 80 °.
In the present embodiment, the side surface PB of the substrate P is subjected to liquid repellent treatment (water repellent treatment). Specifically, the photosensitive material 90 having liquid repellency is also applied to the side surface PB of the substrate P. Accordingly, it is possible to prevent liquid from entering from the gap A between the plate member 32 having a liquid-repellent surface and the side surface of the substrate P. Further, the photosensitive material 90 is also applied to the back surface PC of the substrate P and subjected to a liquid repellent treatment.

  In the present embodiment, the placement surface 52a and the inner side surface 36 of the substrate table 52 have liquid repellency. Furthermore, a part of the surface of the substrate holder PH is also subjected to a liquid repellent treatment to be liquid repellent. In the present embodiment, of the substrate holder PH, the upper surface 33A and the side surface 37 of the peripheral wall portion 33 have liquid repellency. As the liquid repellent treatment of the substrate table 52 and the substrate holder PH, for example, a liquid repellent material such as a fluorine resin material or an acrylic resin material is applied or a thin film made of the liquid repellent material is attached. As the liquid repellent material for making it liquid repellent, a material insoluble in the liquid 1 is used. Note that the entire substrate table 52 and substrate holder PH may be formed of a material having liquid repellency (such as a fluorine-based resin).

  The first space 38 surrounded by the peripheral wall portion 33 of the substrate holder PH is made negative pressure by the suction device 40. The suction device 40 includes a plurality of suction ports 41 provided on the upper surface of the base portion 35 of the substrate holder PH, a vacuum portion 42 including a vacuum pump provided outside the substrate table 52, and a plurality of suction ports 40 formed inside the base portion 35. Each of the suction ports 41 and a vacuum channel 42 are provided. The suction ports 41 are respectively provided at a plurality of predetermined positions other than the support portion 34 on the upper surface of the base portion 35. The suction device 40 sucks gas (air) inside the first space 38 formed between the peripheral wall portion 33, the base portion 35, and the substrate P supported by the support portion 34, and this first space 38. The substrate P is sucked and held on the support portion 34 by making the pressure negative. Since the gap B between the back surface PC of the substrate P and the upper surface 33A of the peripheral wall portion 33 is small, the negative pressure in the first space 38 is maintained.

  The liquid 1 that has flowed into the second space 39 between the inner side surface 36 of the recess 31 and the side surface 37 of the substrate holder PH is recovered by the recovery unit 60. In the present embodiment, the recovery unit 60 includes a tank 61 that can store the liquid 1 and a flow path 62 that is provided inside the substrate table 52 and connects the space 39 and the tank 61. The inner wall surface of the flow path 62 is also subjected to liquid repellent treatment.

Next, a method for exposing the substrate P using the exposure apparatus EX having the above-described configuration will be described.
First, in a state where the coil body 78 is not energized in the elevating device 76 (that is, in a state where the pad portion 75 is lowered), the liquid 1 is supplied to the space 71 in the barrel PK through the supply pipe 12A by the liquid supply mechanism 10. The liquid 1 is filled from the space 71 into the immersion area AR2 surrounded by the bellows tube 74, the pad portion 75, and the substrate P through the through hole 72.

  At this time, the pad portion 75 has an inclined portion 75b in which the distance from the substrate P decreases toward the periphery of the substrate P, and as shown in FIG. 3A, the vertical component of the pressure of the liquid 1 As a result, an upward force is applied, so that the pad portion 75 floats with respect to the substrate P and a minute gap G is formed between the pad portion 75 and the substrate P. Since the gap G has a smaller cross-sectional area than that between the inclined portion 75b and the substrate P, the flow velocity of the liquid 1 entering the gap G is increased, and a boundary layer of the liquid 1 is formed in the gap G. It will be.

On the other hand, the liquid 1 flowing out from between the pad portion 75 and the substrate P through the gap G is drained from the liquid absorption groove 75c through the recovery pipe 21A by the suction force of the liquid recovery mechanism 20 (liquid recovery portion 21).・ Recovered. When the liquid collection part 21 sucks the liquid absorption groove 75c, the inside of the liquid absorption groove 75c becomes negative pressure. Therefore, the force in the direction approaching the substrate P is applied to the pad part 75 (the direction in which the pad part 75 floats). Reverse force) is applied.
Therefore, by adjusting the supply amount of the liquid 1 by the liquid supply unit 12 and the recovery amount of the liquid 1 by the liquid recovery unit 21, the pad portion is controlled by controlling the rising pressure from the liquid 1 and the descending pressure due to liquid absorption. 75 can function as a preload type fluid bearing having a predetermined spring rigidity. In the present embodiment, the pad portion 75 is provided with a predetermined spring by making the supply amount of the liquid 1 substantially constant and adjusting the liquid absorption force (drainage amount) of the liquid recovery unit 21 by the control device CONT as the adjusting device. It is held on the substrate P as a fluid bearing having rigidity.

Therefore, the substrate table 52 is driven based on the detection result of the autofocus system AF, and the focus position (position in the Z-axis direction) of the substrate P and the position in the direction substantially parallel to the image plane of the projection optical system PL are adjusted. Therefore, when the substrate P is displaced, the pad portion 75 follows the position and posture of the substrate P according to the pressure of the liquid 1.
More specifically, when the substrate P (the upper end surface 34A) moves in the direction approaching the pad portion 75 and the gap G becomes smaller during the position control and posture control of the substrate P, the space between the substrate P and the pad portion 75 is reduced. As the pressure of the liquid increases, the pad portion 75 moves away from the substrate P, and conversely when the substrate P moves away from the pad portion 75 and the gap G increases, the substrate P and the pad portion become larger. Since the liquid pressure with respect to 75 decreases, the pad portion 75 moves in a direction approaching the substrate P.

Therefore, even if the substrate P is displaced in any of the Z-axis direction, the θX direction (the rotation direction around the X axis), and the θY direction (the rotation direction around the Y axis), the pad portion 75 is not displaced. Accordingly, since it moves in a direction crossing the upper end surface 34A, the gap between the pad portion 75 and the substrate P is maintained constant, and the pad portion 75 maintains a constant gap with the surface PA of the substrate P. Follow as you do.
Further, when the position and posture of the pad portion 75 change according to the substrate P, the bellows tube 74 can be expanded and / or bent to cope with the displacement of the pad portion 75.

  In this way, when the liquid immersion area AR2 filled with the liquid 1 surrounded by the lens barrel PK, the support member 73, the bellows tube 74, and the pad portion 75 is formed on the substrate P, the control device CONT performs projection. The substrate P is irradiated with the exposure light EL through the optical system PL and the liquid 1, and the pattern image of the mask M is projected onto the substrate P while moving the substrate stage PST supporting the substrate P, thereby exposing the substrate P. Immersion exposure is performed.

Here, in the case of performing exposure on the end portion of the substrate P, so-called edge exposure (edge shot), for example, a part of the pad portion 75 protrudes from the substrate P and is positioned on the substrate table 52 as shown in FIG. Therefore, the liquid 1 leaks from the gap A between the side surface PB of the substrate P and the inner peripheral surface 36 of the substrate table 52, but the leaked liquid 1 is separated from the substrate holder PH and the substrate table 52 by the recovery unit 60. Since the liquid is smoothly recovered from the gap C to the tank 61 via the flow path 62, the liquid immersion exposure is not hindered.
If there is a possibility that the force to lift the pad portion 75 due to the leakage of the liquid 1 may decrease, the amount of liquid to be supplied is increased or the amount of liquid to be absorbed is decreased in consideration of the leakage. It is preferable to make it.

On the other hand, when the substrate P is replaced after the exposure processing for the substrate P is completed, the liquid supply unit 10 first stops the liquid supply after the liquid immersion exposure is completed, and the liquid recovery unit 20 performs the liquid immersion area AR2. The liquid is collected, and the liquid immersion area AR2 is replaced with air from the liquid.
Then, the coil body 78 is energized and the electromagnetic actuator 76 is driven as an electromagnet, thereby attracting the attracting portion 79 and raising the pad portion 75 in the Z-axis direction as shown in FIG. At this time, the bellows tube 74 is contracted, so that the rise of the pad portion 75 is not hindered. As a result, a large gap is formed between the pad portion 75 and the substrate P along the Z-axis direction, so that the substrate P can be exchanged by allowing the transport arm 80 to enter the gap.

  When the replacement of the substrate is completed and the transfer arm 80 is retracted from the substrate table 52, the energization to the coil body 78 is stopped and the pad portion 75 is lowered to form a liquid immersion region. When the energization is stopped, the pad portion 75 may naturally fall and collide with the substrate P. Therefore, the control device CONT gradually lowers the energization amount to the coil body 78, thereby gradually lowering the pad portion 75 and bringing it into contact with the substrate P (soft landing). Thereby, it can prevent that the board | substrate P is damaged by the collision with the pad part 75. FIG.

  As described above, in the present embodiment, even if focus adjustment or posture control is performed on the substrate P, the pad portion 75 of the moving device 70 moves following the position and posture of the substrate P to maintain the gap. Therefore, it is possible to prevent the liquid 1 from leaking and to stably form the liquid immersion area AR2. Therefore, in the present embodiment, stable immersion exposure is possible, and an exposure process with a large focus margin and improved resolution during the exposure operation can be realized. In the present embodiment, since the moving device 70 has a simple configuration of the bellows tube 74 and the pad portion 75, it can be easily mounted on an existing device (current device), and an immersion exposure apparatus. Can be provided at low cost. Furthermore, in the present embodiment, the spring rigidity of the pad portion 75 is adjusted with a simple configuration in which the liquid absorption force by the liquid recovery portion 21 is adjusted, so that the pad portion 75 is complicated to follow the displacement of the substrate P. It is not necessary to provide a mechanism separately, and a cheaper device can be realized.

  Further, in the present embodiment, since the pad portion 75 is moved up and down by the electromagnetic actuator 76, it is possible to easily prevent the substrate P and the transport arm 80 from contacting the pad portion 75 even when the substrate P is replaced. Thus, safety can be improved. In the present embodiment, the lowering speed is also adjusted when the pad portion 75 is lowered, so that it is possible to avoid the substrate P from being damaged by the collision (impact) between the substrate P and the pad portion 75, and the yield. Can also be expected. In addition, in this embodiment, since the electromagnetic actuator 76 is used for raising and lowering the pad portion 75, the pad portion 75 can be vibrationally separated from the lens barrel PK when forming the liquid immersion area AR2. Thus, it is possible to prevent the vibration from being transmitted to the projection optical system PL and adversely affecting the transfer accuracy.

  In the above embodiment, when the edge shot is performed, the liquid 1 leaks from the gap A between the side surface PB of the substrate P and the inner peripheral surface 36 of the substrate table 52, so that the leakage amount is reduced. The inner peripheral surface 75a of the pad portion 75 preferably has a small diameter, but if the diameter of the inner peripheral surface 75a is reduced, there is a possibility of interference with the detection light beam B projected from the light projecting portion AF1 of the autofocus system AF. There is. Therefore, as shown in FIG. 5, a configuration may be adopted in which an inclined surface 75d is provided over the entire circumference at the upper end of the inner peripheral surface 75a so as to leave a gap with the optical path of the detection light beam B. Further, when it is difficult to form an inclined surface over the entire circumference due to problems such as strength, as shown in FIG. 6, the notch 75e is provided only at a location that interferes with the optical path of the detection light beam B. It is good also as a structure to form.

  In the above embodiment, the pad portion 75 is soft-landed on the substrate P by adjusting the amount of current supplied to the coil body 78 when the pad portion 75 is lowered after the substrate P is replaced. For example, an air supply source may be connected to the liquid recovery unit 21 and the pad unit 75 may be lowered while ejecting air from the liquid absorption groove 75c of the pad unit 75. Also in this case, the substrate P can be prevented from being damaged by the collision with the pad portion 75.

  Moreover, in the said embodiment, although the pad part 75 was set as the structure hold | maintained at the board | substrate P by adjusting the liquid absorption force (drainage amount) of the liquid collection | recovery part 21, it is not restricted to this, Liquid absorption force It is good also as a structure which adjusts supply_amount | feed_rate, and changes both a liquid absorption power and a liquid supply amount simultaneously.

  As described above, since ArF excimer laser light is used as exposure light in this embodiment, pure water is supplied as a liquid for immersion exposure. Pure water has the advantage that it can be easily obtained in large quantities at a semiconductor manufacturing factory or the like and has no adverse effect on the photoresist, optical element (lens), etc. on the substrate (wafer). In addition, pure water has no adverse effects on the environment, and since the impurity content is extremely low, it can be expected to clean the surface of the substrate and the surface of the optical element provided on the front end surface of the projection optical system.

It is said that the refractive index n of pure water (water) for exposure light having a wavelength of about 193 nm is approximately 1.44. When ArF excimer laser light (wavelength 193 nm) is used as a light source for exposure light, the wavelength is shortened to 1 / n, that is, about 134 nm on the substrate, and high resolution is obtained. Further, the depth of focus is expanded by about n times, that is, about 1.44 times compared to the air.
In addition, as the liquid, it is possible to use a liquid that is transparent to the exposure light, has a refractive index as high as possible, and is stable with respect to the projection optical system and the photoresist applied to the substrate surface. .
When F ₂ laser light is used as the exposure light, a fluorine-based liquid such as fluorine-based oil or perfluorinated polyether (PFPE) that can transmit the F ₂ laser light may be used as the liquid.

  The present invention can also be applied to a twin stage type exposure apparatus. The structure and exposure operation of a twin stage type exposure apparatus are described in, for example, Japanese Patent Laid-Open Nos. 10-163099 and 10-214783 (corresponding US Pat. Nos. 6,341,007, 6,400,441, 6,549). , 269 and 6,590,634), JP 2000-505958 (corresponding US Pat. No. 5,969,441) or US Pat. No. 6,208,407.

  When the immersion method as described above is used, the numerical aperture NA of the projection optical system may be 0.9 to 1.3. As described above, when the numerical aperture NA of the projection optical system is increased, the imaging characteristics may be deteriorated due to the polarization effect in the case of the random polarized light conventionally used as the exposure light. Is desirable. In that case, linearly polarized illumination is performed in accordance with the longitudinal direction of the line pattern of the mask (reticle) line-and-space pattern. From the mask (reticle) pattern, the S-polarized light component (TE-polarized light component), that is, the line pattern It is preferable that a large amount of diffracted light having a polarization direction component is emitted along the longitudinal direction. When the space between the projection optical system PL and the resist applied on the surface of the substrate P is filled with a liquid, the space between the projection optical system PL and the resist applied on the surface of the substrate P is filled with air (gas). In comparison with the case where the numerical aperture NA of the projection optical system exceeds 1.0, the transmittance of the diffracted light of the S-polarized component (TE-polarized component), which contributes to the improvement of contrast, on the resist surface is increased. High imaging performance can be obtained. Further, it is more effective to appropriately combine a phase shift mask or an oblique incidence illumination method (particularly a dipole illumination method) adapted to the longitudinal direction of the line pattern as disclosed in JP-A-6-188169.

  Further, for example, ArF excimer laser light is used as exposure light, and a fine line and space pattern (for example, L / S of about 25 to 50 nm) is formed on the substrate P by using the projection optical system PL with a reduction magnification of about 1/4. When exposing upward, depending on the structure of the mask M (for example, the fineness of the pattern and the thickness of chrome), the mask M acts as a polarizing plate due to the wave guide effect, and the P-polarized component (TM-polarized component) reduces the contrast. More diffracted light of the S-polarized component (TE polarized component) than the diffracted light of) is emitted from the mask. In this case as well, it is desirable to use linearly polarized illumination as described above, but even if the mask M is illuminated with random polarized light, high resolution is achieved using a projection optical system having a large numerical aperture NA such as 0.9 to 1.3. It becomes possible to obtain performance.

  When an extremely fine line and space pattern on the mask M is exposed on the substrate P, the P-polarized component (TM-polarized component) is replaced with the S-polarized component (TE-polarized component) by the Wave guide effect. Although, for example, ArF excimer laser light is used as exposure light, and a line and space pattern larger than 25 nm is exposed on the substrate P using a projection optical system with a reduction ratio of about 1/4. Under such conditions, the diffracted light of the S-polarized component (TE-polarized component) is emitted from the mask more than the diffracted light of the P-polarized component (TM-polarized component), so the numerical aperture NA of the projection optical system is 0.9. High resolution performance can be obtained even when it is as large as ˜1.3.

  Furthermore, not only linearly polarized illumination (S-polarized illumination) matched to the longitudinal direction of the mask (reticle) line pattern, but also polarized illumination and oblique incidence that linearly polarizes in the tangential (circumferential) direction of the circle around the optical axis. Combination with the lighting method is also effective. In particular, when the mask (reticle) pattern includes not only a line pattern extending in a predetermined direction but also a plurality of line patterns extending in different directions, linear polarization is performed in a tangential direction of a circle centering on the optical axis. By using the polarized illumination method and the annular illumination method in combination, high imaging performance can be obtained even when the numerical aperture NA of the projection optical system is large.

  The substrate P in each of the above embodiments is not only a semiconductor wafer for manufacturing a semiconductor device, but also a glass substrate for a display device, a ceramic wafer for a thin film magnetic head, or an original mask or reticle used in an exposure apparatus. (Synthetic quartz, silicon wafer) or the like is applied.

  As the exposure apparatus EX, in addition to the step-and-scan type scanning exposure apparatus (scanning stepper) that scans and exposes the pattern of the mask M by moving the mask M and the substrate P synchronously, the mask M and the substrate P Can be applied to a step-and-repeat type projection exposure apparatus (stepper) in which the pattern of the mask M is collectively exposed while the substrate P is stationary and the substrate P is sequentially moved stepwise. The present invention can also be applied to a step-and-stitch type exposure apparatus that partially transfers at least two patterns on the substrate P.

  The type of the exposure apparatus EX is not limited to an exposure apparatus for manufacturing a semiconductor element that exposes a semiconductor element pattern on the substrate P, but an exposure apparatus for manufacturing a liquid crystal display element or a display, a thin film magnetic head, an image sensor (CCD). ) Or an exposure apparatus for manufacturing reticles or masks.

  When using a linear motor (see USP5,623,853 or USP5,528,118) for the substrate stage PST and mask stage MST, use either an air levitation type using air bearings or a magnetic levitation type using Lorentz force or reactance force. Also good. Each stage PST, MST may be a type that moves along a guide, or may be a guideless type that does not have a guide.

  As a driving mechanism for each stage PST, MST, a planar motor that drives each stage PST, MST by electromagnetic force with a magnet unit having a two-dimensionally arranged magnet and an armature unit having a two-dimensionally arranged coil facing each other is provided. It may be used. In this case, either one of the magnet unit and the armature unit may be connected to the stages PST and MST, and the other of the magnet unit and the armature unit may be provided on the moving surface side of the stages PST and MST.

As described in JP-A-8-166475 (USP 5,528,118), the reaction force generated by the movement of the substrate stage PST is not transmitted to the projection optical system PL, but mechanically using a frame member. You may escape to the floor (ground).
As described in JP-A-8-330224 (US S / N 08 / 416,558), a frame member is used so that the reaction force generated by the movement of the mask stage MST is not transmitted to the projection optical system PL. May be mechanically released to the floor (ground).

  As described above, the exposure apparatus EX according to the present embodiment maintains various mechanical subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Manufactured by assembling. In order to ensure these various accuracies, before and after assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  As shown in FIG. 7, a microdevice such as a semiconductor device includes a step 201 for designing a function / performance of the microdevice, a step 202 for producing a mask (reticle) based on the design step, and a substrate as a base material of the device. Manufacturing step 203, exposure processing step 204 for exposing the mask pattern onto the substrate by the exposure apparatus EX of the above-described embodiment, device assembly step (including dicing process, bonding process, packaging process) 205, inspection step 206, etc. It is manufactured after.

It is a schematic block diagram which shows one Embodiment of the exposure apparatus of this invention. It is a figure which shows the structure of a liquid immersion area periphery. (A) is a state in which the pad portion is lowered, and (b) is a view showing a state in which the pad portion is lifted and sucked. It is principal part sectional drawing of a substrate stage. It is a fragmentary sectional view showing another form of a pad part. It is a fragmentary sectional view showing another form of a pad part. It is a flowchart figure which shows an example of the manufacturing process of a semiconductor device.

Explanation of symbols

CONT control device (adjustment device)
EX exposure equipment M Mask (reticle)
P substrate PL projection optical system PST substrate stage (stage device)
1 Liquid 21 Liquid recovery unit (Liquid absorption device)
34A Upper end surface (mounting surface)
52 Substrate table (drive device)
70 Moving device 74 Bellows tube (flexible part)
75 Pad part 75b Inclined part 76 Electromagnetic actuator (elevating device)

Claims (11)

A stage device having a mounting surface for mounting a substrate,
A moving device that faces the substrate and has a pad portion having a liquid absorbing portion, and moves in a direction crossing the mounting surface according to the pressure of the liquid between the substrate and the pad portion ;
A recess in which a substrate holder for holding the substrate is disposed;
It leaks from a gap between the side surface of the substrate held by the substrate holder disposed in the recess and the inner surface of the recess, and flows into the space between the inner surface of the recess and the side surface of the substrate holder. A recovery unit for recovering the collected liquid;
A stage apparatus comprising: The stage apparatus according to claim 1, wherein
The pad portion floats with respect to the substrate with the pressure of the liquid,
The stage device characterized in that the moving device has a flexible portion that has flexibility and suspends the pad portion. The stage apparatus according to claim 1 or 2,
The stage device according to claim 1, wherein the pad portion has an inclined portion in which a distance between the substrate and the pad portion decreases toward a periphery of the substrate. In the stage apparatus as described in any one of Claim 1 to 3,
A stage device comprising: a liquid absorbing device that absorbs liquid that has flowed out between the moving device and the substrate. The stage apparatus according to claim 4, wherein
The moving device has spring stiffness;
A stage apparatus comprising: an adjusting device that adjusts the liquid absorption force of the liquid to adjust the spring rigidity of the moving device. In the stage apparatus as described in any one of Claim 1 to 5,
A stage apparatus comprising: an elevating device that elevates and lowers at least a part of the moving device in a direction perpendicular to the placement surface. The stage apparatus according to claim 6, wherein
A stage device comprising a control device for controlling the lifting device when the substrate is replaced. The stage apparatus according to any one of claims 1 to 7,
A stage apparatus comprising: a driving device that drives the substrate in the intersecting direction.   In the stage device according to any one of claims 1 to 8,
  A stage apparatus that is disposed around the recess and has a flat surface that is substantially the same height as the surface of the substrate held by the substrate holder. In an exposure apparatus that exposes a pattern to a substrate placed on a stage apparatus,
An exposure apparatus using the stage apparatus according to any one of claims 1 to 9 . The exposure apparatus according to claim 10 , wherein
A projection optical system for projecting the pattern onto the substrate;
An exposure apparatus, wherein at least a part of the moving device is connected to the projection optical system.

Images