HK1201945B - Measurement method, stage apparatus, and exposure apparatus - Google Patents

Description

Measurement method, stage device, and exposure device

The application is a divisional application of an invention patent application with the application number of 200880025096.X and the name of 'measuring method, stage device and exposure device', and the application date of the original application is 2008-16.07/16.

Technical Field

The present invention relates to a measurement technique and a stage technique for measuring positional information of a movable member such as a stage for moving an object, an exposure technique for exposing an object using the stage technique, and a device manufacturing technique for manufacturing devices such as a semiconductor device and a liquid crystal display device using the exposure technique.

Background

In a lithography process for manufacturing devices (electronic devices, microdevices) such as semiconductor devices and liquid crystal display devices, exposure apparatuses such as a stationary exposure type (one-shot exposure type) projection exposure apparatus such as a stepper and a scanning type projection exposure apparatus (scanning exposure apparatus) such as a scanning stepper are mainly used to project and expose a circuit pattern formed on a reticle (or a mask) onto a wafer (or a glass plate or the like) coated with a resist through a projection optical system. In such an exposure apparatus, in order to reduce positional distortion or overlay error of a circuit pattern to be manufactured, a laser interferometer using a frequency stabilized laser as a light source has been conventionally used for position measurement of a stage for positioning or moving a wafer or the like.

In a laser interferometer, the refractive index of a gas on an optical path through which a laser beam is transmitted varies depending on the temperature, pressure, humidity, and the like of the body, and the variation in refractive index causes variation in the measurement value of the interferometer (oscillation of the interferometer). Therefore, in the conventional exposure apparatus, a temperature-controlled gas blowing system is used to blow a temperature-controlled gas onto an optical path of a measuring beam of the interferometer, and the temperature of the gas in the optical path is stabilized to reduce the fluctuation of the interferometer. Recently, in order to further improve the temperature stability of the gas on the optical path of the measuring beam of the laser interferometer, there has been proposed an exposure apparatus in which at least a part of the optical path of the measuring beam is covered with a cylindrical cover or the like (see, for example, patent documents 1 and 2).

Patent document 1: japanese laid-open patent publication No. 5-2883313

Patent document 2: japanese laid-open patent publication No. 8-261718

As described above, when a laser interferometer is used, a measure for preventing the wobble is required. However, particularly in a wafer stage of a scanning exposure apparatus, when the stage to be measured moves vertically and horizontally at a high speed, the air flow irregularly fluctuates due to the movement of the stage, and therefore there is a problem that the interferometer shakes to some extent.

The present invention has been made in an effort to provide a measurement technique and a stage technique that can reduce the influence of the refractive index variation of the ambient gas, an exposure technique that can improve the positioning accuracy of the stage using the stage technique, and a device manufacturing technique using the exposure technique.

Disclosure of Invention

The 1 st measuring method of the present invention is a method for measuring displacement information of a movable member relative to a predetermined member, comprising: a step of providing a scale on one of the predetermined member and the movable member, and providing a plurality of detectors capable of detecting the scale on the other; integrally supporting the scale or the plurality of detectors provided on the predetermined member with a supporting member having a smaller linear expansion coefficient than the movable member; and a step of measuring displacement information of the movable member from the detection results of the plurality of detectors.

The 2 nd measuring method of the present invention is a measuring method for measuring displacement information of a movable member by detecting a scale provided on the movable member with a plurality of detectors, comprising: a step of integrally supporting the plurality of detectors with a support member; and a step of measuring displacement information of the movable member from the detection results of the plurality of detectors; the support member is connected to the base member having a larger linear expansion coefficient than the support member by a plurality of flexure members whose tip portions are displaceable in a direction along the scale surface relative to the base member.

The stage apparatus of the present invention, which can position a stage with respect to a predetermined member, includes: a scale provided on one of the stage and the predetermined member; a plurality of detectors provided on the other of the stage and the predetermined member, for detecting information relating to the position of the scale; a support member integrally supporting the scale or the plurality of detectors provided to the predetermined member and having a linear expansion coefficient smaller than that of the stage; and a control device for obtaining the displacement information of the stage from the detection results of the plurality of detectors.

The 1 st exposure device of the invention, irradiate the exposure light to the substrate and form the predetermined pattern on the substrate; the carrying platform device of the invention is used for positioning the substrate.

A 2 nd optical device according to the present invention is an optical device for irradiating a substrate held by a movable stage with exposure light to form a predetermined pattern on the substrate, the optical device including: a scale arranged on the carrying platform; a plurality of detectors for detecting information relating to the position of the scale; a support member that integrally supports the plurality of detectors; a base member having a linear expansion coefficient larger than that of the support member; a coupling mechanism that couples the support member to the base member in a state of being displaceable in a direction along the scale surface; and a control device for obtaining displacement information of the stage from the detection results of the plurality of detectors; the coupling mechanism includes a plurality of flexure members that couple the support member and the base member and whose front end portion is displaceable in a direction along the scale surface.

The device manufacturing method of the present invention is a device manufacturing method including a lithography process in which the exposure apparatus of the present invention is used.

According to the present invention, since the scale provided on the movable member (or stage) or the predetermined member is detected by the detector, it is not necessary to provide an optical path of the same degree as the movement stroke of the movable member as in the case of the laser interferometer. The influence of the refractive index variation of the ambient gas can be reduced. When the scale of the movable member or the predetermined member is separated from the detection target region of one detector, for example, the measurement can be continued by switching to another detector that can detect the scale. In this case, since the linear expansion coefficient of the support member is smaller than that of the movable member or the base member, even if the ambient temperature fluctuates, the fluctuation in the positional relationship between the plurality of detectors or within the scale can be suppressed, and the measurement error when the plurality of detectors are switched can be reduced. Therefore, in the case of the exposure apparatus, the positioning accuracy of the stage can be improved.

Drawings

Fig. 1 is a view showing a part of the schematic configuration of an exposure apparatus according to embodiment 1.

Fig. 2 is a plan view showing the stage device of fig. 1.

Fig. 3 is a sectional view showing the measuring frame 21 of fig. 1.

FIG. 4 shows the alignment systems AL1, AL2 of FIG. 1₁～AL2₄And a diagram of the arrangement of the position measuring encoder.

Fig. 5(a) is a plan view showing the wafer stage, and fig. 5(B) is a side view showing a partial cross section of the wafer stage.

Fig. 6(a) is a plan view showing the measurement stage, and fig. 6(B) is a side view showing a partial cross section of the measurement stage.

Fig. 7 is a block diagram showing a main configuration of a control system of the exposure apparatus according to embodiment 1.

Fig. 8(a) and 8(B) are views for explaining the positional measurement of the wafer stage in the XY plane and the connection of the measurement values between the heads by the plurality of encoders each including the plurality of heads arranged in an array.

Fig. 9(a) shows an example of the encoder structure, and fig. 9(B) shows a case where a laser beam LB having a cross-sectional shape extending long in the periodic direction of the grid RG is used as the detection light.

Fig. 10(a) is a view showing a state where measurement of the first alignment irradiation region AS is performed, fig. 10(B) is a view showing a state where measurement of the second alignment irradiation region AS is performed, and fig. 10(C) is a view showing an example of arrangement of the alignment irradiation regions AS of the wafer.

Fig. 11 is a flowchart showing an example of the measurement and exposure operation according to embodiment 1.

FIG. 12 is a view showing a part of the schematic configuration of the exposure apparatus according to embodiment 2.

FIG. 13 is a view showing a part of the schematic configuration of the exposure apparatus according to embodiment 3.

Fig. 14 is an enlarged perspective view of a main portion of fig. 13.

Fig. 15 is an explanatory diagram of an operation when the lengths of the measurement frame and the head base in fig. 13 are changed.

Fig. 16(a) is a view showing the elongated rod-shaped member, and fig. 16(B) is a view showing the flexing member formed with the groove portion.

Fig. 17 is a perspective view showing a part of the connection method of the modification of fig. 13.

FIG. 18 is a flowchart for explaining an example of the process of manufacturing the microdevice.

FIG. 19 is a view showing a state in which a main part of an exposure apparatus according to another embodiment is partially omitted.

Fig. 20 is a bottom view along line AA of fig. 19.

20: main control devices 21, 21M: measuring frame

26: the head base 32: mouth unit

39X₁,39X₂: x scale 39Y₁,39Y₂: y-shaped scale

62A to 62D: the head unit 64: y read head

66: x read heads 70A, 70C: y encoder

70B, 70D: the X encoder 113: flexing member

AL 1: first alignment system AL2₁～AL2₄: second alignment system

AS: irradiation area MTB: measuring table

MST: measurement stage R: reticle

W: wafer WTB: wafer platform

WST: wafer carrying platform

Detailed Description

[ embodiment 1 ]

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

Fig. 1 schematically shows the structure of an exposure apparatus 100 according to the present embodiment. The exposure apparatus 100 is a scanning type exposure apparatus of a step-and-scan method, i.e., a so-called scanner. As will be described later, in the present embodiment, the projection optical system PL is provided, and hereinafter, a direction parallel to the optical axis AX of the projection optical system PL is referred to as a Z-axis direction, a direction in which the reticle and the wafer are relatively scanned in a plane orthogonal to the Z-axis direction is referred to as a Y-axis direction, a direction orthogonal to the Z-axis and the Y-axis is referred to as an X-axis direction, and directions of rotation (inclination) about the X-axis, the Y-axis, and the Z-axis are referred to as θ X, θ Y, and θ Z directions, respectively.

The exposure apparatus 100 includes: an illumination system 10; a reticle stage RST for holding a reticle R illuminated with the exposure illumination light (exposure light) IL of the illumination system 10; a projection unit PU including a projection optical system PL for projecting the illumination light IL emitted from the reticle R onto the wafer W; stage device 50 having wafer stage WST and measurement stage MST; and a control system for the above apparatus. Wafer W is loaded on wafer stage WST.

The illumination system 10 includes a light source, an illumination optical system including an illuminance uniformizing optical system including an optical integrator (fly eye lens, rod integrator (internal reflection type integrator), diffractive optical element, etc.), and a reticle blind (none of which are shown), as disclosed in, for example, japanese patent application laid-open No. 2001-313250 (corresponding to U.S. patent application laid-open No. 2003/0025890). The illumination system 10 illuminates a slit-shaped illumination area IAR on a reticle R defined by a reticle blind with substantially uniform illumination by illumination light IL. As an example, an ArF excimer laser (wavelength 193nm) is used as the illumination light IL. For example, a KrF excimer laser (wavelength 247nm), an F2 laser (wavelength 157nm), a harmonic of a YAG laser, a harmonic of a solid-state laser (semiconductor laser, etc.), a bright line (i, etc.) of a mercury lamp, or the like can be used as the illumination light IL.

A reticle R having a circuit pattern or the like formed on a pattern surface (lower surface) thereof is fixed to the reticle stage RTS by, for example, vacuum suction. Reticle stage RST can be driven slightly in the XY plane by reticle stage driving system 11 of fig. 7 including, for example, a linear motor or the like, and can be driven in the scanning direction (Y direction) at a predetermined scanning speed.

The position of reticle stage RST in fig. 1 (including rotation information in the θ z direction) in the moving plane is detected at any time by reticle interferometer 116 via moving mirror 15 (which may be a reflecting surface obtained by mirror-finishing the end surface of the stage), for example, with an analytical capability of about 0.5 to 1 nm. The measurement values of the reticle interferometer 116 are transmitted to the main control device 20 of fig. 7. Main controller 20 calculates the position of reticle stage RST in at least the X direction, the Y direction, and the θ z direction from the measurement values of reticle interferometer 116, and controls the position and speed of reticle stage RST by controlling reticle stage drive system 11 based on the calculation result. Further, reticle interferometer 116 may measure position information of reticle stage RST in at least one of the Z direction, θ x, and θ y directions.

In fig. 1, projection unit PU disposed below reticle stage RST includes lens barrel 40; and a projection optical system PL having a plurality of optical elements held in a predetermined positional relationship in the lens barrel 40. As the projection optical system PL, for example, a refractive optical system including a plurality of lens elements arranged along the optical axis AX is used. The projection optical system PL is, for example, telecentric on both sides and has a predetermined projection magnification β (for example, 1/4 times, 1/5 times, 1/8 times, or the like). When illumination area IAR is illuminated with illumination light IL from illumination system 10, a circuit pattern image of reticle R in illumination area IAR is formed by projection optical system PL on exposure area IA (conjugate to illumination area IAR) on wafer W whose surface is coated with a resist (photosensitive agent) by illumination light IL passing through reticle R.

The exposure apparatus 100 performs exposure by using a liquid immersion method. In this case, a catadioptric system including a mirror and a lens may be used as the projection optical system PL. In addition to the photosensitive layer, a protective film (top coat film) for protecting the wafer or the photosensitive layer may be formed on the wafer W.

Since the exposure apparatus 100 of the present embodiment performs exposure using the liquid immersion method, the nozzle unit 32 constituting a part of the local liquid immersion apparatus 8 is provided so as to surround the periphery of the lower end portion of the lens barrel 40 holding the front end lens 191, the front end lens 191 being a lens constituting an optical element on the most image plane side (wafer W side) of the projection optical system PL.

In fig. 1, the nozzle unit 32 has a supply port through which the exposure liquid Lq can be supplied and a recovery port through which the exposure liquid Lq can be recovered. A porous member (mesh) is disposed in the recovery port. The lower surface of the nozzle unit 32, which can face the front surface of the wafer W, includes flat surfaces arranged to surround the lower surface of the porous member and the opening through which the illumination light IL passes. The supply port is connected to a liquid supply device 186 (see fig. 7) capable of supplying the exposure liquid Lq through a supply channel formed in the nozzle unit 32 and the supply pipe 31A. The recovery port is connected to a liquid recovery device 189 (see fig. 7) capable of recovering at least the liquid Lq through a recovery flow path formed inside the nozzle unit 32 and a recovery pipe 31B.

The liquid supply device 186 includes a liquid tank, a pressure pump, a temperature control device, and a flow control valve for controlling supply and stop of the liquid to the supply pipe 31A, and is capable of supplying the clean exposure liquid Lq with the temperature adjusted. The liquid recovery device 189 is a tank and a suction pump containing liquid, and a flow rate control valve for controlling recovery and stop of the liquid through the recovery tube 31B, and can recover the exposure liquid Lq. Further, the liquid tank, the pressure (suction) pump, the temperature control device, the control valve, and the like, the exposure apparatus 100 need not be provided in its entirety, and at least a part thereof may be replaced with equipment in a factory in which the exposure apparatus 100 is installed.

The operations of the liquid supply apparatus 186 and the liquid recovery apparatus 189 in fig. 7 are controlled by the main control apparatus 20. The exposure liquid Lq sent from the liquid supply device 186 of fig. 7 flows through the supply channel of the supply tube 31A and the nozzle unit 32 of fig. 1, and is then supplied from the supply port to the optical path space of the illumination light IL. Further, by driving the liquid recovery device 189 of fig. 7, the exposure liquid Lq recovered from the recovery port passes through the recovery flow path of the nozzle unit 32, and is then recovered by the liquid recovery device 189 through the recovery pipe 31B. The main controller 20 in fig. 7 fills the liquid immersion area 14 (see fig. 3) including the optical path space of the illumination light IL between the front end lens 191 and the wafer W in fig. 1 with the liquid Lq to form a liquid immersion space for the liquid Lq by simultaneously performing the liquid supply operation of the supply port and the liquid recovery operation of the recovery port of the nozzle unit 32.

In the present embodiment, pure water that transmits ArF excimer laser light (light having a wavelength of 193nm) is used as the exposure liquid Lq. Pure water has an advantage that it can be easily obtained in a large amount in a semiconductor manufacturing plant or the like and does not adversely affect a resist, an optical lens, or the like on a wafer. The refractive index n of water to ArF excimer laser light is approximately 1.44. In this water, the wavelength of the illumination light IL is shortened to 193nm × 1/n, which is about 134nm, and thus the resolution can be improved.

As is clear from the above description, the local immersion apparatus 8 of the present embodiment includes the nozzle unit 32, the liquid supply device 186, the liquid recovery device 189, the liquid supply pipe 31A and the liquid recovery pipe 31B, and the like. Further, a part of the local immersion unit 8, for example, at least the nozzle unit 32 may be suspended from a main frame (including the lens barrel holder) for holding the projection unit PU, or may be provided in a frame member different from the main frame. In the present embodiment, the nozzle unit 32 is provided in a measurement frame suspended and supported independently from the projection unit PU. In this case, the projection unit PU may be supported without being suspended.

Even when measurement stage MST is positioned below projection unit PU in fig. 1, a space between the measurement stage and front end lens 191, which will be described later, can be filled with water in the same manner as described above. In the above description, as an example, each of the liquid supply tube (nozzle) and the liquid recovery tube (nozzle) is provided, but the present invention is not limited to this, and a configuration having a plurality of nozzles as disclosed in, for example, pamphlet of international publication No. 99/49504 may be adopted as long as the arrangement is possible in consideration of the relationship with the surrounding members. In brief, the configuration may be any as long as it is a configuration capable of supplying liquid between the optical member (tip lens) 191 constituting the lowermost end of the projection optical system PL and the wafer W. For example, the exposure apparatus of the present embodiment can be applied to a liquid immersion mechanism disclosed in pamphlet of international publication No. 2004/053955, a liquid immersion mechanism disclosed in specification of european patent publication No. 1420298, and the like.

Returning to fig. 1, stage device 50 includes; a wafer stage WST and a measurement stage MST, which are arranged above the base 12; an interferometer system 118 (see fig. 7) including Y-axis interferometers 16 and 18 for measuring position information of the stages WST and MST; an encoder system described later for measuring position information of wafer stage WST at the time of exposure or the like; and stage drive system 124 (see fig. 7) for driving stages WST and MST.

Non-contact bearings (not shown), for example, vacuum pre-pressurized air hydrostatic bearings (hereinafter referred to as "air pads") are provided at a plurality of positions on the bottom surfaces of wafer stage WST and measurement stage MST, and wafer stage WST and measurement stage MST are supported on top of base 12 in a non-contact manner through a gap of about several μm by the static pressure of pressurized air ejected from these air pads onto base 12. Further, stages WST and MST can be independently driven in two-dimensional directions of the Y direction and the X direction by stage driving system 124 of fig. 7.

In more detail, as shown in the plan view of fig. 2, on the ground, a pair of Y-axis fixing members 86,87 extending in the Y-axis direction are disposed on one side and the other side in the X-axis direction, respectively, with the base 12 interposed therebetween. The Y-axis fixtures 86,87 are constituted by, for example, magnetic pole units in which permanent magnet groups constituted by a plurality of sets of N-pole magnets and S-pole magnets alternately arranged at predetermined intervals in the Y-axis direction are built. The two Y-axis movable members 82,84,83, and 85 are provided in the Y-axis fixing members 86 and 87, respectively, in a non-contact engagement state. That is, the total of four Y-axis movable members 82,84,83,85 are inserted into the inner space of the Y-axis fixed member 86 or 87 having the U-shaped XZ cross section, and are supported by the corresponding Y-axis fixed member 86 or 87 in a non-contact manner through an air cushion, not shown, for example, with a gap of several μm. Each of the Y-axis movers 82,84,83,85 is constituted by, for example, an armature element unit in which armature coils are arranged at a predetermined interval in the Y-axis direction. That is, in the present embodiment, the Y-axis linear motors of the moving coil type are constituted by the Y-axis movable elements 82 and 84 constituted by the armature element units and the Y-axis fixed element 86 constituted by the magnetic pole units, respectively. Similarly, the Y-axis linear motors of the moving coil type are constituted by the Y-axis movable members 83 and 85 and the Y-axis fixed member 87, respectively. Hereinafter, the four Y-axis linear motors are appropriately referred to as a Y-axis linear motor 82, a Y-axis linear motor 84, a Y-axis linear motor 83, and a Y-axis linear motor 85, using the same reference numerals as those of the movable members 82,84,83, and 85, respectively.

Of the four Y-axis linear motors, the movable members 82 and 83 of the two Y-axis linear motors 82 and 83 are fixed to one end and the other end in the longitudinal direction of the X-axis fixing member 80 extending in the X-axis direction, respectively. The movable members 84,85 of the remaining two Y-axis linear motors 84,85 are fixed to one end and the other end of the X-axis fixing member 81 extending in the X-axis direction. Accordingly, the X-axis mounts 80,81 can be driven along the Y-axis by a pair of Y-axis linear motors 82,83,84,85, respectively.

Each of the X-axis anchors 80,81 is composed of, for example, an armature element unit in which armature coils are installed at a predetermined interval in the X-axis direction.

An X-axis fixing member 81 is inserted into an opening (not shown) formed in stage main body 91 (constituting a part of wafer stage WST, see fig. 1). Inside the opening of the stage main body 91, for example, a magnetic pole unit having a permanent magnet group composed of a plurality of sets of N-pole magnets and S-pole magnets alternately arranged at predetermined intervals in the X-axis direction is provided. The magnetic pole unit and the X-axis fixing unit 81 constitute a moving magnet type X-axis linear motor for driving the stage main body 91 in the X-axis direction. Similarly, the other X-axis fixing member 80 is inserted into an opening (not shown) formed in the stage main body 92 (constituting the measurement stage MST). A magnetic pole unit similar to that on the wafer stage WST side (stage main body 91 side) is provided inside the opening of the stage main body 92. The magnetic pole unit and the X-axis fixing unit 80 constitute a moving magnet type X-axis linear motor for driving the measurement stage MST in the X-axis direction.

In the present embodiment, each of the linear motors constituting stage drive system 124 is controlled by main control device 20 shown in fig. 7. The linear motors are not limited to either of the moving magnet type and the moving coil type, and can be appropriately selected as needed. By slightly changing the thrust forces generated by the pair of Y-axis linear motors 84 and 85 (or 82 and 83), the deflection (rotation in the direction of θ z) of wafer stage WST (or measurement stage MST) can be controlled.

Wafer stage WST, comprising: the stage body 91; and a wafer table WTB mounted on the stage main body 91 by a not-shown Z leveling mechanism (e.g., a voice coil motor) and capable of being driven slightly in the Z-axis direction, the θ x direction, and the θ y direction with respect to the stage main body 91.

The wafer table WTB is provided with a wafer holder (not shown) for holding the wafer W by vacuum suction or the like. The wafer holder may be formed integrally with the wafer table WTB, but in the present embodiment, the wafer holder and the wafer table WTB are separately configured, and the wafer holder is fixed in the recess of the wafer table WTB by, for example, vacuum suction. A plate (liquid-repellent plate) 28 having a rectangular outer shape and a circular opening formed at the center thereof so as to be larger than the wafer holder (wafer mounting area) is provided on the wafer table WTB. The plate 28 is made of a material having a low thermal expansion coefficient, such as glass or ceramic (trade name: Zerodur, Seidel), or Al₂O₃Or TiC) and made of a fluororesin material, a fluororesin material such as polytetrafluoroethylene (teflon (registered trademark)), an acrylic resin material, orA silicone resin material, etc. to form a liquid repellent film.

As shown in the plan view of wafer table WTB (wafer stage WST) in fig. 5A, plate body 28 has a 1 st liquid repellent area 28a having a rectangular outer shape (outline) surrounding a circular opening, and a 2 nd liquid repellent area 28b having a rectangular frame shape (ring shape) disposed around 1 st liquid repellent area 28 a. For example, during exposure operation, the 1 st liquid repellent region 28a is formed with at least a part of the liquid immersion region 14 (see fig. 3) extending from the wafer surface, and the 2 nd liquid repellent region 28b is formed with a scale for an encoder system to be described later. In addition, at least a portion of the surface of the plate 28 may not be flush with the surface of the wafer, i.e., may be at a different height. The plate 28 may be a single plate, but in the present embodiment, it is a plurality of plates, for example, a 1 st and a 2 nd liquid-repellent plate corresponding to the 1 st and the 2 nd liquid-repellent regions 28a and 28b, respectively, are combined. Since the liquid Lq in the present embodiment is pure water, for example, a water repellent coating is applied to the liquid repellent regions 28a and 28 b.

In this case, the illumination light IL hardly irradiates the outer 2 nd water paddle 28b, as opposed to the 1 st water paddle 28a on which the illumination light IL irradiates the inner side. In view of this, in the present embodiment, a water repellent coating film having sufficient resistance to the illumination light IL (in this case, light in the vacuum ultraviolet region) is applied to the surface of the 1 st water repellent plate 28a, and a water repellent coating film having less resistance to the illumination light IL than the 1 st water repellent region 28a is applied to the surface of the 2 nd water repellent plate 28 b.

As is clear from fig. 5A, a rectangular notch is formed in the center portion in the X direction of the + Y direction side end portion of the 1 st water-repelling region 28a, and the measurement plate 30 is embedded in the rectangular space (inside the notch) surrounded by this notch and the 2 nd water-repelling region 28 b. A reference mark FM is formed at the center in the longitudinal direction of the measurement plate 30 (on the center line LL of the wafer table WTB), and a pair of aerial image measurement slit patterns (slit-shaped measurement patterns) SL arranged symmetrically with respect to the center of the reference mark are formed on one side and the other side in the X direction of the reference mark. For example, an L-shaped slit pattern having sides extending in the Y direction and the X direction, two linear slit patterns extending in the X direction and the Y direction, or the like is used for each aerial image measuring slit pattern SL.

As shown in fig. 5B, an L-shaped housing accommodating light transmission system 36 (including an optical system including an objective lens, a mirror, a relay lens, and the like) is mounted in a state of penetrating a part of the inside of stage main body 91 from wafer table WTB, and a part of the L-shaped housing is embedded in the inside of wafer stage WST below each aerial image measuring slit pattern SL. Although not shown, the light transmission system 36 is provided in a pair corresponding to the pair of aerial image measurement slit patterns SL. The light transmission system 36 guides the illumination light IL transmitted through the aerial image measuring slit pattern SL along an L-shaped path and emits the illumination light IL in the Y direction.

Furthermore, a plurality of grid lines 37,38 are directly formed on the upper surface of the 2 nd water repellent region 28b at predetermined pitches along the four sides thereof. More specifically, Y scales 39Y are formed on both sides (right and left sides in fig. 5A) in the X direction of the 2 nd water-repellent region 28b₁,39Y₂The Y scale 39Y₁,39Y₂For example, the grating is formed of a reflection type grating (for example, a phase type diffraction grating) in which lattice lines 38 extending in the X direction are formed at a predetermined pitch in a direction (Y direction) parallel to the Y axis and are periodically arranged in the Y direction.

Similarly, an X scale 39X is formed in each of the regions on one side and the other side (upper and lower sides in fig. 5A) in the Y axis direction of the 2 nd water repellent region 28b₁,39X₂The X scale 39X₁,39X₂For example, the reflection type grating is formed of a reflection type grating (for example, a diffraction grating) which is formed by grid lines 37 extending in the Y direction at a predetermined pitch in a direction (X direction) parallel to the X axis and is periodically arranged in the X direction.

Each scale 39Y₁,39Y₂,39X₁,39X₂For example, a hologram or the like is used to form a reflection type diffraction grating on the surface of the 2 nd water repellent area 28 b. In this case, each scale is a grid of narrow slits, grooves, or the like, which is engraved at a predetermined interval (pitch). The type of diffraction grating used for each scale is not limited, and the diffraction grating may be mechanicalThe grooves may be formed by sintering interference fringes on a photosensitive resin, for example. Each scale is formed by, for example, scribing the scale of the diffraction grating on a thin plate glass at a pitch of 138nm to 4 μm (for example, 1 μm pitch). These scales are covered with the aforementioned liquid-repellent film (water-repellent film). In fig. 5A, for convenience of illustration, the pitch of the grid is illustrated to be much larger than the actual pitch. This point is the same in other figures.

As described above, in the present embodiment, since the 2 nd water repellent region 28b itself is configured as a scale, a glass plate having low thermal expansion is used as the 2 nd water repellent region 28 b. However, the scale member may be fixed to the upper surface of the wafer table WTB by a plate spring (or vacuum suction) or the like so as to prevent local expansion and contraction, and in this case, a water-repellent plate having the same water-repellent coating film applied over the entire surface may be used as the plate body 28.

the-Y end face and the-X end face of the wafer table WTB are mirror-finished to form reflection surfaces 17a and 17b shown in fig. 2, respectively. The Y-axis interferometer 16 and the X-axis interferometer 126 (see fig. 2) of the interferometer system 118 (see fig. 7) project interferometer beams (ranging beams) onto the reflecting surfaces 17a and 17b, respectively, and receive the reflected light from the reflecting surfaces. Then, interferometers 16 and 126 measure the displacement of each reflection surface from a reference position (for example, a reference mirror disposed in projection unit PU), that is, positional information of wafer stage WST in the XY plane, and supply the measured values to main controller 20. In the present embodiment, a multi-axis interferometer having a plurality of optical axes is used as both the Y-axis interferometer 16 and the X-axis interferometer 126, and the main controller 20 can measure not only the X and Y positions of the wafer table WTB from the measurement values of these Y-axis interferometers 16 and 126, but also rotation information in the θ X direction (pitch), rotation information in the θ Y direction (roll), and rotation information in the θ z direction (yaw).

In the present embodiment, positional information (including rotation information in the θ z direction) of wafer stage WST (wafer table WTB) in the XY plane is mainly measured by an encoder system described later including the Y scale, the X scale, and the like, and the measurement values of interferometers 16 and 126 are used for auxiliary correction (correction) of long-term variations (for example, caused by changes in the scales with time) and the like of the encoder system. The purpose of the Y-axis interferometer 16 is to measure the Y position of the wafer table WTB and the like near an unloading position and a loading position, which will be described later, in order to exchange wafers. Further, at least one of the measurement information of interferometer system 118, that is, the position information in the five-degree-of-freedom direction (X-axis, Y-axis, θ X, θ Y, and θ z direction) is also used when wafer stage WST moves during the loading operation and the alignment operation, and/or during the exposure operation and the unloading operation, for example.

Further, Y-axis interferometer 16 and X-axis interferometer 126 of interferometer system 118, and Y-axis interferometer 18 and X-axis interferometer 130 for measurement stage MST described later are supported by the bottom surface of measurement frame 21 via support members 24A,24C,24B, and 24D, as shown in fig. 3 which is a top view of measurement frame 21 in fig. 1. However, the Y-axis interferometers 16,18 and the X-axis interferometers 126,130 may be provided on a main frame that holds the projection unit PU, or may be provided integrally with the projection unit PU suspended and supported as described above. In such cases, the interferometer 16,18,126,130 may include only a portion of the interferometer optical system for separating and combining the distance measuring beam directed to the stage and the reference beam directed to the reference mirror, and a portion of the receiver (photodetector) for receiving the interference light of the distance measuring beam and the reference beam is supported by a not-shown column.

In the present embodiment, wafer stage WST includes a stage main body 91 that is movable in the XY plane, and a wafer table WTB that is mounted on stage main body 91 and is slightly driven in the Z direction, the θ x direction, and the θ Z direction with respect to stage main body 91. Instead of the reflection surface 17b, a movable mirror formed of a flat mirror may be provided on the wafer table WTB. Further, the position where the reference mirror (reference surface) is disposed is not limited to the projection unit PU, and it is not necessarily required to measure the position information of the wafer stage WST using a fixed mirror.

In the present embodiment, the positional information of wafer stage WST measured by interferometer system 118 is mainly used for the calibration operation of the encoder system (i.e., the calibration of the measurement values) and the like, not for the exposure operation, the alignment operation, and the like, which will be described later, but the measurement information of interferometer system 118 (i.e., at least one of the positional information in the five-degree-of-freedom direction) may be used for the exposure operation, the alignment operation, and the like, for example. In the present embodiment, the encoder system measures positional information of wafer stage WST in three-degree-of-freedom directions, i.e., the X direction, the Y direction, and the θ z direction. Therefore, during exposure operation, the measurement information of interferometer system 118 may be obtained by using only the position information in the θ X direction and/or the θ Y direction, which is different from the measurement direction (X direction, Y direction, and θ z direction) of the position information of wafer stage WST by the encoder system, or by using the position information in the same direction as the measurement direction of the encoder system (i.e., at least one of the X direction, Y direction, and θ z direction) in addition to the position information in the different direction. Interferometer system 118 can also measure position information of wafer stage WST in the Z-axis direction. In this case, the position information in the Z-axis direction can also be used in the exposure operation.

In the measurement stage MST of fig. 1, a flat plate-shaped measurement table MTB is fixed to a stage main body 92. Various measuring members are provided on measuring table MTB and stage main body 92. As the measuring means, for example, as shown in fig. 2 and 6A, an illuminance unevenness sensor 94 having a pinhole-like light receiving section, an aerial image measuring instrument 96 for measuring an aerial image (projection image) of a pattern projected by the projection optical system PL, a wavefront aberration measuring instrument 98, and the like are used.

In the present embodiment, liquid immersion exposure is performed in which the wafer W is exposed to the illumination light IL through the projection optical system PL and the liquid (water) Lq, and in response to this, the uneven illuminance sensor 94 (and the illuminance monitor), the aerial image measuring instrument 96, and the wavefront aberration measuring instrument 98 for measurement using the illumination light IL receive the illumination light IL through the projection optical system PL and the water. As shown in fig. 6B, frame-shaped mounting member 42 is fixed to a-Y-direction side end surface of stage main body 92 of measurement stage MST. Further, a pair of light receiving systems 44 are fixed to the-Y-direction side end surface of stage body 92 in such a manner that they can face the pair of light transmitting systems 36 in fig. 5B in the vicinity of the center position in the X direction inside the opening of mounting member 42. Each light receiving system 44 is composed of an optical system such as a relay lens, a light receiving element (for example, a photomultiplier tube), and a housing that houses these components. As is clear from fig. 5B and 6B and the description up to this point, in the present embodiment, in a state (including a contact state) in which wafer stage WST and measurement stage MST are within a predetermined distance in the Y-axis direction, illumination light IL transmitted through each aerial image measurement slit pattern SL of measurement plate 30 is guided by each light-transmitting system 36 and received by the light-receiving elements of each light-receiving system 44. That is, the measurement plate 30, the light transmitting system 36, and the light receiving system 44 constitute the aerial image measuring apparatus 45 (see FIG. 7) similar to that disclosed in the aforementioned Japanese patent application laid-open No. 2002-14005 (corresponding to the specification of the U.S. patent application publication No. 2002/0041377).

A reference bar (hereinafter, simply referred to as "CD bar") 46 as a reference member made of a bar-shaped member having a rectangular cross section is provided to the mounting member 42 of fig. 6B so as to extend in the X-axis direction. The CD bar 46 is dynamically supported on the measurement stage MST by a fully dynamic frame structure.

Since the CD bar 46 is a master (measurement standard), the material thereof is optical glass ceramic having a low thermal expansion coefficient, for example, Zerodur (trade name) of seidel corporation. The flatness of the upper surface (surface) of the CD bar 46 is set high to the same degree as that of a so-called reference plane plate. As shown in fig. 6A, reference lattices (e.g., diffraction gratings) 52 each having a period direction in the Y direction are formed in the vicinity of one end and the other end in the longitudinal direction of the CD bar 46. The pair of reference lattices 52 are formed symmetrically with respect to the center of the CD bar 46 in the X-axis direction, i.e., with respect to the center line CL, with a predetermined distance (L) therebetween.

A plurality of reference marks M are formed on the upper surface of the CD bar 46 in the arrangement shown in fig. 6A. The plurality of reference marks M are arranged in three rows in the Y-axis direction at the same pitch, and the rows are arranged to be offset from each other by a predetermined distance in the X-direction. Each of the reference marks M is, for example, a two-dimensional mark having a size detectable by a first alignment system and a second alignment system described later. The shape (configuration) of the fiducial marks M may be different from the fiducial marks FM of fig. 5A, but in the present embodiment, the fiducial marks M and the fiducial marks FM have the same configuration, and also have the same configuration as the alignment marks of the wafer W. In the present embodiment, the surface of the CD bar 46 and the surface of the measurement table MTB (which may include the measurement member) are each covered with a liquid repellent film (water repellent film).

As shown in fig. 2, the + Y end surface and the-X end surface of measurement table MTB also have reflection surfaces 19a and 19b similar to those of wafer table WTB. The Y-axis interferometer 18 and the X-axis interferometer 130 of the interferometer system 118 (see fig. 7) project interferometer beams (ranging beams) onto the reflection surfaces 19a and 19b, respectively, and receive the respective reflected lights to measure the displacement of the reflection surfaces from the reference position, that is, the positional information of the measurement stage MST (including, for example, positional information in the X direction and the Y direction and rotation information in the θ z direction), and supply the measured values to the main control device 20.

As shown in fig. 2, brake mechanisms 48A and 48B are provided at both ends of the X-axis fixtures 81 and 80 in the X direction. A brake mechanism 48A, comprising: the dampers 47A,47B are shock absorbers provided to the X-axis fixing member 81 and are, for example, shock absorbing devices formed of oil dampers; openings 51A,51B provided at opposite positions of the dampers 47A,47B of the X-axis fixing member 80; and shutters 49A,49B for opening and closing these openings. The open/close state of the openings 51A,51B of the shutters 49A,49B is detected by a switch sensor (see fig. 7)101 provided in the vicinity of the shutters 49A,49B, and the detection result is sent to the main control device 20.

Here, the operation of the brake mechanisms 48A and 48B will be described with the brake mechanism 48A as a representative.

In fig. 2, when the X-axis mount 81 and the X-axis mount 80 approach each other in a state where the shutter 48A is closing the opening 51A, the X-axis mounts 80,81 cannot approach each other due to contact (abutment) of the damper 47A and the shutter 49A. On the other hand, when the shutter 49A is opened to open the opening 51A, when the X-axis fixtures 81 and 80 approach each other, at least a part of the front end portion of the damper 47A enters the opening 51A, and the X-axis fixtures 80 and 81 can approach each other. As a result, wafer table WTB and measurement table MTB (CD bar 46) can be brought into contact with each other (or brought close to each other to a distance of about 300 μm).

In fig. 2, the X-axis fixing member 80 is provided at the + X end with the interval detection sensors 43A,43C and the impact detection sensors 43B,43D, and the X-axis fixing member 81 is provided at the + Y side with the elongated plate-like member 41A extending in the Y direction. The interval detection sensors 43A,43C are, for example, transmission type photo sensors (e.g., sensors composed of LED-phototransistor elements), and the X-axis fixing member 80 and the X-axis fixing member 81 are brought close to each other, so that the plate-like member 41A enters between the interval detection sensors 43A, and the amount of light received is reduced, and thus it is possible to detect that the interval between the X-axis fixing members 80,81 is smaller than a predetermined distance.

The impact detection sensors 43B,43D are the same photoelectric sensors as the gap detection sensors 43A,43C, and are disposed at the depths thereof. With the impact detection sensors 43B,43D, at the stage when the X-axis fixtures 81,80 are closer to each other and the wafer table WTB is in contact with the CD bar 46 (measuring table MTB) (or at the stage when the X-axis fixtures are closer to each other, the upper half of the plate-like member 41A is positioned between the elements of the sensors, and therefore the main controller 20 detects that the two are in contact with each other (or close to a distance of about 300 μm) by detecting that the amount of light received by the sensors is zero.

Although the exposure apparatus 100 of the present embodiment is omitted in fig. 1 in order to avoid an excessively complicated drawing, in actuality, as shown in fig. 4, a first alignment system AL1 is arranged, and this first alignment system AL1 has a detection center at a position spaced apart from the optical axis toward the-Y side by a predetermined distance on a straight line LV passing through the center of the projection unit PU (coinciding with the optical axis AX of the projection optical system PL, and coinciding with the center of the exposure area IA in the present embodiment) and parallel to the Y axis. The first alignment system AL1 is fixed to the measurement frame 21 by the support member 54 (see fig. 1). PartitionThe first alignment system AL1 is provided with a second alignment system AL2 having a detection center arranged substantially symmetrically with respect to the straight line LV on one side and the other side in the X-axis direction₁,AL2₂And AL2₃,AL2₄. That is, five alignment systems AL1, AL2₁～AL2₄The detection centers of (b) are arranged at different positions in the X direction, that is, along the X direction.

Each second alignment system AL2_n(n-1-4) as representative of the alignment system shown AL2₄In general, the arm 56 is fixed to the arm so as to be rotatable in the clockwise and counterclockwise directions in fig. 4 about the rotation center O within a predetermined angular range_n(n is 1 to 4) a tip (rotation end). In the present embodiment, each second alignment system AL2_nIs fixed to the arm 56 (e.g., an optical system including at least a light guide for guiding light generated from an object mark in the detection area to a light receiving element) in part thereof_nAnd the remaining portion is disposed on the measuring frame 21. Second alignment System AL2₁,AL2₂,AL2₃,AL2₄The X position can be adjusted by rotating around the rotation center O. That is, the second alignment system AL2₁,AL2₂,AL2₃,AL2₄The detection area (or the detection center) of (a) can be independently moved in the X-axis direction. In addition, in the present embodiment, the second alignment system AL2 is adjusted by the rotation of the arm₁,AL2₂,AL2₃,AL2₄But not limited thereto, a second alignment system AL2 may be provided₁,AL2₂,AL2₃,AL2₄A driving mechanism for driving in the X direction in a reciprocating manner. Also, a second alignment system AL2₁,AL2₂,AL2₃,AL2₄May also be movable not only in the X direction but also in the Y direction. In addition, due to the second alignment systems AL2_nIs formed by arm 56_nCan be moved and thus can be measured by a sensor not shown, such as an interferometer or encoder, secured to the arm 56_nA portion of the location information. The sensor may measure only the second alignment system AL2_nPosition information in the X direction, also enabling it to be measuredPosition information in other directions such as the Y direction and/or the rotational direction (including at least one of the thetax and thetay directions).

At each arm 56_nOn the upper surface, a vacuum pad 58 composed of a differential exhaust type air bearing is provided_n(n is 1 to 4). Also, the arm 56_nFor example by means of a rotary drive mechanism comprising a motor or the like_n(n is 1 to 4, see fig. 7), and is rotatable in accordance with an instruction from the main control device 20. Main control device 20 is on arm 56_nAfter the rotation adjustment, the vacuum pads 58 are adjusted_nAct to move each arm 56_nIs fixed to the measuring frame 21 by suction (see fig. 1). Thus, each arm 56 can be maintained_nI.e. maintaining the first alignment system AL1 and the 4 second alignment systems AL2₁～AL2₄The desired positional relationship of (a).

In addition, it is only necessary to measure the arm 56 of the frame 21_nA magnetic material may be fixed to the facing portion, and an electromagnet may be used instead of the vacuum pad 58.

The first alignment system AL1 and the 4 second alignment systems AL2 of the present embodiment₁～AL2₄For example, a Field Image Alignment (FIA) system of an Image processing system may be used, which irradiates a target mark with a wide-band detection beam that does not expose a resist on a wafer, and captures an Image of the target mark imaged on a light receiving surface by reflected light from the target mark and an Image of an index (an index pattern on an index plate provided in each Alignment system) not shown by an imaging element (a Charge Coupled Device (CCD)) and outputs the captured signals. From alignment systems AL1 and AL2₁～AL2₄The respective imaging signals are supplied to the main controller 20 of fig. 7.

The alignment systems are not limited to the FIA system, and it is needless to say that an alignment sensor capable of detecting scattered light or diffracted light generated from an object mark by irradiating coherent detection light to the object mark or interfering two diffracted lights generated from the object mark (for example, diffracted light of the same order or diffracted light of the same order) may be used alone or in combination as appropriateDirectional diffracted light) to be detected. In the present embodiment, five alignment systems AL1 and AL2 are provided₁～AL2₄Therefore, alignment can be performed more efficiently. However, the number of alignment systems is not limited to five, and may be two or more and four or less, or six or more, or may be an even number instead of an odd number. Also, only the first alignment system AL1 may be used. In the present embodiment, there are five alignment systems AL1 and AL2₁～AL2₄The support member 54 is fixed to the measurement frame 21, but is not limited thereto, and may be fixed to a lower surface of a main frame for holding the projection unit PU.

As shown in fig. 4, the exposure apparatus 100 of the present embodiment is configured such that four head units 62A to 62D of an encoder system are arranged so as to surround the periphery of the nozzle unit 32 from four directions. The plurality of Y heads 64 and X heads 66 constituting these head units 62A to 62D are fixed to the bottom surface of the flat plate-like measuring frame 21 (see fig. 1) by fixing members (not shown) as indicated by two-dot chain lines in fig. 4. The fixing member includes, for example, a plurality of bushings (fixed by being embedded in the measurement frame 21 and then bonded thereto) made of a low expansion coefficient metal (e.g., steel) on which female screws are formed, and bolts for fixing the housings of the heads 64 and 66 of the head units 62A to 62D to the corresponding bushings.

The material of the measuring frame 21 is, for example, a material having coefficients of linear expansion of. + -. 0.2 × 10^-7Low expansion glass (for example, CLEARCERAM-ZHS (trade name) by OHARA GmbH or low expansion glass ceramic (for example, Zerodur (trade name) by Jed corporation)) within a degree of/(+ -0.02 ppm/K). further, as a material for measuring the frame 21, a material having a linear expansion coefficient of + -0.5 × 10 can be used^-6Low expansion glass within the range of +/-0.5 ppm/K, super factor steel with linear expansion coefficient smaller than that of factor steel, etc.

In this connection, the material of main body portion of loading plate body 28 of wafer table WTB of wafer stage WST and stage main body 91 of wafer stage WST in fig. 1 has a linear expansion coefficient of, for example, 0.1 × 10^-4Iron (steel material) of the order of/K (10ppm/K) or a coefficient of linear expansion of1×10^-6Factor steel of the order of/K (1ppm/K), and the like. As a result, the linear expansion coefficient of measurement frame 21 of the present embodiment is compared with that of wafer stage WST on which scale 39Y is formed₁,39Y₂,39X₁,39X₂The linear expansion coefficient of the members (the main body of wafer stage WST) other than plate body 28 in fig. 5A is set to be as small as, for example, about 1/2 to 1/50.

As shown in fig. 1, the exposure apparatus 100 of the present embodiment is installed on a floor surface FL in a processing chamber, not shown. Holder 12 for guiding wafer stage WST is disposed on floor surface FL via, for example, a plurality of vibration prevention stages (not shown). L-shaped suspension members 22A,22B, and 22C (see fig. 3) surrounding the fixed base 12 are fixed to three places on the floor surface FL, and the measurement frame 21 is suspended and supported from the front end portions of the suspension members 22A,22B, and 22C by vibration-proof members 23A,23B, and 23C. The vibration preventing members 23A to 23C are members that cut off vibrations by, for example, an air spring system, a hydraulic system, or a mechanical spring system.

In fig. 3, the columns 105A,105B, and 105C are provided on three ground surfaces formed at positions spaced apart from the measurement frame 21 in the Y direction and at positions along the-X direction side surfaces of the measurement frame 21. Between the columns 105A,105B and the measuring frame 21, X-axis sensors 106XA,106XB for measuring the displacement of the measuring frame 21 in the X direction and Z-axis sensors 106ZA,106ZB for measuring the displacement of the measuring frame 21 in the Z direction are respectively installed. Further, a Y-axis sensor 106Y for measuring the displacement of the measurement frame 21 in the Y direction and a Z-axis sensor 106ZC for measuring the displacement of the measurement frame 21 in the Z direction are mounted between the column 105C and the measurement frame 21. The six-axis sensors 106XA,106XB,106Y,106ZA to 106ZC may be interferometers, capacitance type displacement sensors, eddy current type displacement sensors, or the like. These six-axis sensors 106XA to 106ZC measure displacements of the measurement frame 21 in the X direction, the Y direction, the Z direction, the θ X direction, the θ Y direction, and the θ Z direction with respect to the ground with a predetermined sampling plate at high accuracy, and supply the measured values to the control unit 108.

Further, X-axis actuators 107XA,107XB for displacing the measurement frame 21 in the X direction and Z-axis actuators 107ZA,107ZB for displacing the measurement frame 21 in the Z direction are respectively attached between the column frames 105A,105B and the measurement frame 21. Further, between the column 105C and the measurement frame 21, a Y-axis actuator 107Y for displacing the measurement frame 21 in the Y direction and a Z-axis actuator 107ZC for displacing the measurement frame 21 in the Z direction are attached. The six-axis non-contact type actuators 107XA,107XB, and 107ZA to 107ZC may be voice coil motors, for example, but may be electromagnetic actuators such as EI coil type actuators, for example. These six-axis actuators 107XA to 107ZC control six-degree-of-freedom displacement of the measuring frame 21 with respect to the ground. Under the control of the main controller 20 in fig. 7, the controller 108 servoly drives the six-axis actuators 107XA to 107ZC so that the six-degree-of-freedom displacement of the measurement frame 21 with respect to the ground is within a predetermined allowable range based on the measurement values of the six-axis actuators 107XA to 107ZC during scanning exposure. In addition, a main frame (not shown) for supporting the projection unit PU may be used as a reference for displacement measurement and displacement control of the measurement frame 21.

In fig. 1, during operation of the exposure apparatus 100, a highly clean and temperature-stabilized gas (for example, dry air or the like) is supplied at a predetermined flow rate by a down-flow method from air outlets 6A,6B of a ceiling of a processing chamber (not shown) in which the exposure apparatus 100 is housed, as indicated by arrows 7A, 7B. Part of the supplied gas is recovered from a recovery port (not shown) provided in the floor surface FL, and then returned to the processing chamber from the air blowing ports 6A and 6B again through the dust-proof filter and the temperature control unit. At this time, as shown in fig. 3, a plurality of openings 25 are formed at predetermined intervals in the X direction and the Y direction on the substantially entire surface of the area of the measurement frame 21 surrounding the projection unit PU so that the gas can smoothly flow in the processing chamber in a downflow manner. This improves the temperature stability of wafer W on wafer stage WST.

Next, in fig. 4, head units 62A and 62C are provided with a plurality of (six in this case) Y heads 64 arranged at predetermined intervals in the X direction on a straight line LH passing through the optical axis AX of the projection optical system PL and parallel to the X axis, respectively, on the + X side and the-X side of the projection unit PU. Y head 64 is formed by using the sameY scale 39Y of FIG. 5A₁Or 39Y₂The position (Y position) of wafer stage WST (wafer table WTB) in the Y direction is measured. Head units 62B and 62D include a plurality of X heads 66 (seven and eleven in this case (however, three not shown in fig. 4 that overlap with first alignment system AL1 in eleven) disposed at predetermined intervals in the Y direction on a straight line LV that passes through optical axis AX and is parallel to the X axis) on the + Y side and the-Y side of projection unit PU. The X heads 66 are respectively used with the X scale 39X of FIG. 5A₁Or 39X₂The position (X position) of wafer stage WST (wafer table WTB) in the X direction is measured.

Therefore, the head units 62A and 62C in fig. 4 are respectively configured using the Y scale 39Y in fig. 5A₁And 39Y₂Y-axis linear encoders (hereinafter, referred to as "Y encoders" where appropriate) 70A and 70C for a plurality of eyes (here, six eyes) for measuring the Y position of wafer stage WST (wafer table WTB) (see fig. 7). Y encoders 70A and 70C include switching control units 70Aa and 70Ca, respectively, for switching (described in detail later) the measurement values of Y heads 64. Here, the interval between adjacent Y heads 64 (i.e., the measurement beams emitted from Y heads 64) of head units 62A and 62C is set to be larger than that of Y scale 39Y₁,39Y₂The width in the X direction (more precisely, the length of the lattice line 38) is narrow. Further, among the plurality of Y heads 64 provided in each head unit 62A,62C, the Y head 64 and the X head 66 positioned on the innermost side are fixed to the measurement frame 21 at the lower end portion of the barrel 40 of the projection optical system PL (more precisely, the lateral side of the nozzle unit 32 surrounding the tip lens 191) so as to be disposed on the optical axis AX as much as possible.

The head units 62B and 62D are basically configured using the X scale 39X described above₁And 39X₂X-axis linear encoders (hereinafter, referred to as "X encoders" where appropriate) 70B and 70D for measuring a plurality of eyes (here, seven eyes and eleven eyes) at the X position of wafer stage WST (wafer table WTB) (see fig. 7). The X encoders 70B and 70D are provided with switching control units 70Ba and 70Da, respectively, for switching (described in detail later) the measurement values of the plurality of X heads 66. In the present embodiment, for example, two of the eleven X heads 66 included in the head unit 62D at the time of alignment described later are providedThe X heads 66 may simultaneously face the X scale 39X₁And 39X₂. At this time, the X scale 39X is used₁And 39X₂The X linear encoders 70B and 70D are configured with the X head 66 facing thereto.

The interval between adjacent X heads 66 (measuring beams) provided in the head units 62B,62D is set to be longer than the X scale 39X₁,39X₂The width in the Y direction (more precisely, the length of the lattice line 37) is narrow.

Furthermore, in the second alignment system AL2 of FIG. 4₁Of the-X side, second alignment system AL2₄On the + Y side of (A), Y head 64Y is provided on a straight line (passing through the detection center of first alignment system AL 1) parallel to the X axis, and the detection points thereof are arranged substantially symmetrically with respect to the detection center₁,64y₂. Y read head 64Y₁,64y₂The distance (d) is set to be substantially equal to the distance (L) (the distance in the Y direction of the reference grid 52 in fig. 6A). Y read head 64Y₁,64y₂In the state shown in fig. 4 where the center of the wafer W on the wafer stage WST is on the straight line LV, the Y scales 39Y are respectively aligned with₂,39Y₁Are opposite. The Y scale 39Y is used for alignment operation described later₂,39Y₁Are respectively connected with the Y head 64Y₁,64y₂Arranged oppositely to each other, by the Y head 64Y₁,64y₂(i.e., by these Y heads 64Y₁,64y₂Y encoders 70C,70A) configured to measure the Y position (and the angle in the θ z direction) of wafer stage WST.

In the present embodiment, when baseline measurement of the second alignment system, which will be described later, is performed, the pair of reference lattices 52 and the Y head 64Y of the CD bar 46 in fig. 6A are aligned with each other₁,64y₂Are respectively opposite to each other by the Y head 64Y₁,64y₂The Y position of the CD bar 46 is measured for each of the reference lattices 52 facing each other 52. Then, the Y head 64Y facing the reference grid 52 is used₁,64y₂The linear encoders thus constructed are referred to as Y encoders 70E and 70F (see fig. 7).

The measurement values of the six encoders 70A to 70E are supplied to the main controller 20, and the main controller 20 controls the position of the wafer table WTB in the XY plane based on the measurement values of the encoders 70A to 70D, and controls the rotation of the CD bar 46 in the θ z direction based on the measurement values of the Y encoders 70E, 70F.

As shown in fig. 4, the exposure apparatus 100 of the present embodiment is provided with a multipoint focus position detection system of an oblique incidence type (hereinafter, simply referred to as "multipoint AF system") similar to that disclosed in, for example, japanese patent application laid-open No. 6-283403 (corresponding to U.S. Pat. No. 5,448,332) and the like, which are constituted by the irradiation system 90a and the light receiving system 90 b. In the present embodiment, as an example, the irradiation system 90a is disposed on the-Y side of the-X end of the head unit 62C, and the light receiving system 90b is disposed on the-Y side of the + X end of the head unit 62A in a state opposed thereto.

The plurality of detection points of the multipoint AF system (90a,90b) of fig. 4 are arranged at predetermined intervals in the X direction on the detection surface. In the present embodiment, for example, the detection points are arranged in a matrix of M rows and M columns (M is the total number of detection points) or two rows and N columns (N is 1/2 of the total number of detection points). Fig. 4 does not individually show a plurality of detection points to which the detection beams are irradiated, but shows an elongated detection area AF extending in the X direction between the irradiation system 90a and the light receiving system 90 b. Since the length of the detection area AF in the X direction is set to be the same as the diameter of the wafer W, the substantially entire Z-direction position information (surface position information) of the wafer W can be measured by scanning the wafer W only once in the Y direction. The detection area AF is arranged in the Y direction between the liquid immersion area 14 (exposure area IA) and the alignment system (AL1, AL 2)₁～AL2₄) The detection operation can be performed by the multi-spot AF system and the alignment system at the same time. The multi-spot AF system may be installed in a main frame or the like for holding the projection unit PU, but in the present embodiment, it is installed in the measurement frame.

In addition, although the plurality of detecting points are arranged in 1 row, M columns or 2 rows, N columns, the number of rows and/or columns is not limited thereto. However, when the number of rows is 2 or more, it is preferable that the positions of the detection points in the X direction are also different between the rows. Further, the plurality of detection points are arranged along the X direction, but the present invention is not limited to this, and all or a part of the plurality of detection points may be arranged at different positions in the Y direction.

In the exposure apparatus 100 of the present embodiment, a pair of Z position measuring surface position sensors (hereinafter, simply referred to as "Z sensors") 72a,72b, 72c, and 72d are provided in the vicinity of detection points located at both ends of a multi-spot AF system (90a,90b), that is, in the vicinity of both ends of a detection area AF, in a symmetrical arrangement with respect to the straight line LV. These Z sensors 72a to 72d are fixed, for example, below the measuring frame 21 of fig. 3. The Z sensors 72a to 72d are optical displacement sensors (CD pickup type sensors) each including an optical pickup used in, for example, a CD drive device, and measure positional information of the surface of the wafer table WTB in the Z direction orthogonal to the XY plane at the irradiation point of the light by irradiating the wafer table WTB with light from above and receiving the reflected light. The Z sensors 72a to 72d may be disposed on the main frame of the projection unit PU.

The head unit 62C includes a plurality of (six in this case, twelve in total) Z sensors 74 located on one side and the other side with a straight line LH (connecting a plurality of Y heads 64) in the X direction interposed therebetween and arranged at predetermined intervals along two straight lines parallel to the straight line LH_i,j(i-1, 2, j-1, 2, …, 6). At this time, the paired Z sensors 74_1,jZ sensor 74_2,jIs arranged symmetrically with respect to the straight line LH. Furthermore, a plurality of pairs (here, six pairs) of Z sensors 74_1,jZ sensor 74_2,jThe plurality of Y heads 64 are arranged alternately in the X direction. Each Z sensor 74_i,jFor example, the same CD pickup type sensors as those of the Z sensors 72a to 72d are used.

Here, each pair of Z sensors 74 located symmetrically with respect to the straight line LH_1,j,74_2,jThe interval of (b) is set to be the same as the interval of the Z sensors 74c,74 d. Also, a pair of Z sensors 74_1,4,74_2,4Is located in parallel with the Y direction the same as the Z sensors 72a,72bOn a straight line.

The head unit 62A includes a plurality of Z sensors 74 opposed to the straight line LV_i,jA plurality of, here 12, Z sensors 76 arranged symmetrically_p,q(p ═ 1,2, q ═ 1,2, …, 6). Each Z sensor 76_p,qFor example, the same CD pickup type sensors as those of the Z sensors 72a to 72d are used. Also, a pair of Z sensors 76_1,3,76_2,3Is located on the same line in the Y direction as the Z sensors 72a,72 b. Z sensor 74_i,jAnd 76_p,qIs fixed to the bottom surface of the measuring frame 21.

Note that, in fig. 4, measurement stage MST is not shown, and liquid immersion area 14 formed by water Lq held between measurement stage MST and tip end lens 191 is shown. In fig. 4, reference numeral 78 denotes a local air conditioning system for sending the dry air whose temperature has been adjusted to a predetermined temperature to the vicinity of the light beam path of the multipoint AF system (90a,90b) by downflow along the white arrows shown in fig. 4. Note that, a symbol UP indicates an unloading position at which the wafer is unloaded onto the wafer table WTB, and a symbol LP indicates a loading position at which the wafer is loaded onto the wafer table WTB. In the present embodiment, the unloading position UP and the loading position LP are set symmetrically with respect to the straight line LV. The unloading position UP and the loading position LP can be set to the same position.

Fig. 7 shows a main configuration of a control system of the exposure apparatus 100. The control system is mainly a main control device 20 constituted by a microcomputer (or a workstation) for integrating the entire device. In fig. 7, various sensors provided on measurement stage MST, such as uneven illuminance sensor 94, aerial image measuring device 96, and wavefront aberration sensor 98, are collectively referred to as a sensor group 99.

Since exposure apparatus 100 of the present embodiment configured as described above employs the arrangement of the X and Y scales on wafer table WTB and the arrangement of the X and Y heads, the effective stroke range of wafer stage WST (that is, the effective stroke range of wafer stage WST in the present embodiment) as shown in the examples of fig. 8A and 8BThe range moved for alignment and exposure operations), the X scale 39X₁,39X₂Are always opposed to the head units 62B,62D (X head 66) respectively, and the Y scale 39Y₁,39Y₂And head units 62A,62C (Y head 64) or Y head 64Y₁,64y₂Must be respectively opposite. In fig. 8A and 8B, heads facing the X scale or the Y scale are illustrated as being circled.

Therefore, main controller 20 can control the positional information (including the rotation information in the θ z direction) of wafer stage WST in the XY plane with high accuracy by controlling each motor constituting stage drive system 124 based on the measured values of at least three of encoders 70A to 70D in the effective stroke range of wafer stage WST. Since the influence of air fluctuation on the measurement values of the encoders 70A to 70D is small enough to be almost ignored compared with the interferometer, the short-term stability of the measurement values due to air fluctuation is much better than that of the interferometer. In the present embodiment, the dimensions (e.g., the number of heads and/or the spacing) of head units 62A,62B,62C, and 62D are set in accordance with the effective stroke range of wafer stage WST, the size of the scale (i.e., the range in which the diffraction grating is formed), and the like. Therefore, in the effective stroke range of wafer stage WST, four scales 39X₁,39X₂,39Y₁,39Y₂Although each of the four scales faces the head units 62B,62D,62A, and 62C, not all of the four scales may face the corresponding head units. For example, X scale 39X₁,39X₂And/or a Y scale 39Y₁,39Y₂May also be disengaged from the head unit. When X scale 39X₁,39X₂One side of (2) or a Y scale 39Y₁,39Y₂When one of the three scales is disengaged from the head unit, the three scales still face the head unit in the effective stroke range of wafer stage WST, and therefore, the positional information of wafer stage WST in the X-axis, Y-axis, and θ z directions can be measured at any time. When the X scale 39X is used₁,39X₂One side of (2) or a Y scale 39Y₁,39Y₂When one of the two scales is separated from the head unit, the two scales and the two scales are in the effective stroke range of the wafer stage WSTSince the head units face each other, the positional information of wafer stage WST in the θ z direction cannot be measured at any time, but the positional information of the X axis and the Y axis can be measured at any time. At this time, the position of wafer stage WST may be controlled by using the position information of wafer stage WST in the θ z direction measured by interferometer system 118.

When wafer stage WST is driven in the X direction as indicated by the white arrow in fig. 8A, Y head 64 for measuring the position of wafer stage WST in the Y direction is indicated by arrow e in the drawing₁,e₂Shown sequentially switched to the adjacent Y read head 64. For example, switching from the Y head 64 framed by the solid circles to the Y head 64 framed by the broken circles. Thus, the measured values are connected by the switching control sections 70Aa,70Ca in the Y encoders 70A,70C of fig. 7 before and after the switching. That is, in the present embodiment, in order to smoothly switch the Y heads 64 and connect the measured values, the distance between adjacent Y heads 64 provided in the head units 62A and 62C is set to be larger than the distance between the Y scales 39Y and 62C as described above₁,39Y₂The width in the X direction is narrow.

In the present embodiment, as described above, the distance between adjacent Y heads 66 provided in head units 62B and 62D is set to be larger than the distance on the X scale 39X₁,39X₂Since the width in the Y direction is narrow, as described above, when wafer stage WST is driven in the Y direction as indicated by the white arrow in fig. 8B, X heads 66 for measuring the position of wafer stage WST in the X direction are sequentially switched to adjacent X heads 66 (for example, X heads 66 framed by solid circles are switched to X heads 66 framed by dashed circles), and the measurement values are connected by switching control units 70Ba,70Da in X encoders 70A,70C of fig. 7 before and after the switching.

Next, the configuration of Y head 64 and X head 66 of encoders 70A to 70F will be described, with Y encoder 70A shown in fig. 9A as a representative enlarged view. In FIG. 9A, the Y scale 39Y is irradiated with the detection light (measuring beam)₁One Y head 64 of the head unit 62A.

The Y head 64 is largely composed of three parts, i.e., an irradiation system 64a, an optical system 64b, and a light receiving system 64 c. The irradiation system 64a includes a light source (e.g., a semiconductor laser LD) that emits a laser beam LB in a direction at 45 ° with respect to the Y axis and the Z axis, and a lens L1 disposed on the optical path of the laser beam LB emitted from the semiconductor laser LD. The optical system 64b includes a polarizing beam splitter PBS whose separation plane is parallel to the XZ plane, a pair of mirrors R1a, R1b, lenses L2a, L2b, quarter-wave plates (hereinafter referred to as λ/4 plates) WP1a, WP1b, mirrors R2a, R2b, and the like.

The light receiving system 64c includes a polarizer (light detector), a photodetector, and the like. In the Y head 64 of the Y encoder 70A, the laser beam LB emitted from the semiconductor laser LD is incident on the polarization beam splitter PBS through the lens L1, and is polarization-separated into two beams LB₁,LB₂. Light beam LB transmitted through polarizing beam splitter PBS₁Then, the reflected beam passes through a mirror R1a to reach a scale 39Y formed on the Y scale₁The reflection type diffraction grating RG of (1), the light beam LB reflected by the polarizing beam splitter PBS₂It reaches the reflection-type diffraction grating RG through the mirror R1 b. Here, "polarization separation" means separation of an incident light beam into a P-polarized component and an S-polarized component.

By means of a light beam LB₁,LB₂The diffracted light beam generated from the diffraction grating RG for a predetermined number of times, for example, 1-time diffracted light beam, is converted into circularly polarized light by the λ/4 plates WP1a and WP1b through the lenses L2b and L2a, and then reflected by the mirrors R2a and R2b to pass through the λ/4 plates WP1a and WP1b again, and reaches the polarization beam splitter PBS in the opposite direction of the same optical path as the return path. The two light beams that reach the polarization beam splitter PBS have their respective polarization directions rotated by 90 degrees with respect to the original direction. Thus, the light beam LB that is transmitted through the polarizing beam splitter PBS first₁The 1 st-order diffracted light beam (B) is reflected by the polarizing beam splitter PBS and enters the light receiving system 64c, and the light beam LB reflected by the polarizing beam splitter PBS first₂The 1 st-order diffracted light beam is transmitted through the polarizing beam splitter PBS and then is combined with the light beam LB₁The-1 st-order diffracted light beams are incident on the optical receiving system 64c coaxially. Then, the two + -1 st order diffracted light beams are integrated with the polarization of the light-detected object in the light-receiving system 64cAnd interfere with each other to become interference light, which is detected by a photodetector and converted into an electrical signal corresponding to the intensity of the interference light.

In addition, for example, LB may be added₁,LB₂An optical system for branching and combining generates interference light having a phase different from that of the interference light by 90 DEG, and performs photoelectric conversion on the interference light to generate an electrical signal. At this time, by using two phase electric signals having a phase difference of 90 °, a Y scale 39Y can be generated₁1/2 of periods (spacings) are further interpolated to more than a few hundredths of a measurement pulse, for example, to improve measurement analysis.

As is clear from the above description, in the Y encoder 70A, since the optical path lengths of the two light fluxes interfering with each other are extremely short and substantially equal, the influence of air fluctuation can be almost ignored. When the Y scale 39Y is used₁When (i.e., wafer stage WST) is moved in the measurement direction (in this case, the Y direction), the respective phases of the two light beams change, and the intensity of the interference light changes. The intensity change of the interference light is detected by the light receiving system 64c, and the position information corresponding to the intensity change is outputted as the measurement value of the Y encoder 70A. The other encoders 70B,70C,70D, etc. are also configured in the same manner as the encoder 70A. Each encoder has an analysis capability of, for example, about 0.1 nm. As shown in fig. 9B, the encoder of the present embodiment uses, as the detection light, a laser beam LB having a cross-sectional shape extending in the periodic direction of the grid RG in the lateral direction. In fig. 9B, the light beam LB is exaggeratedly illustrated in comparison with the grid RG.

Next, an operation example for performing position measurement and exposure of wafer stage WST in exposure apparatus 100 according to the present embodiment will be described with reference to the flowchart of fig. 11. First, in step 201 of fig. 11, the plurality of encoder heads (X head 66 and Y head 64) of the X-axis and Y-axis head units 62A to 62D and the Y-axis interferometers 16 and 18 and the X-axis interferometers 126 and 130, which are interferometer systems of the multi-axis wafer interferometers, are mounted on the measurement frame 21 of fig. 3.

Next, in step 202, the measurement frame 21 is suspended from the suspension members 22A to 22C of fig. 3 by the vibration prevention members 23A to 23C. Thereafter, the front end of the projection unit PU is passed through the opening 21a of the measurement frame 21, and the liquid immersion mechanism including the nozzle unit 32 is attached.

In the next step 203, the scale 39X of FIG. 5A is formed₁,39X₂,39Y₁,39Y₂Plate body 28 of (a) is provided on wafer table WTB, assembly adjustment of wafer stage WST is performed, and six-axis sensors 106XA to 106ZC (displacement sensors) and six-axis actuators 107XA to 107ZC shown in fig. 3 are mounted on measurement frame 21. The operations of steps 201 to 203 are performed in a clean room during, for example, assembly adjustment of the exposure apparatus 100. After the completion of the assembly adjustment, the exposure apparatus 100 is stored in a predetermined processing chamber.

Next, when the operation of the exposure apparatus 100 is started, in step 204 of fig. 11, the down flow of the clean gas is started in the processing chamber in which the exposure apparatus is housed. The next step 205 is to use the sensors 106 XA-106 ZC of FIG. 3. The six-degree-of-freedom displacement of the measuring frame relative to the pylons 105A to 105C (ground) is measured and made within an allowable range by actuators 107XA to 107 ZC. Next, in step 206, wafer stage WST is moved at a low speed, the movement amount of wafer stage WST relative to measurement frame 21 (projection optical system PL) is measured by X head 66, Y head 64 (encoder head), and Y-axis interferometer 16 and X-axis interferometer 126 of the wafer interferometer, and the measurement values of X head 66 and Y head 64 (head units 62A to 62D) are corrected (calibration) based on the measurement results. This correction is described in detail below.

That is, the scale of the encoder is deformed by the diffraction grating due to thermal expansion or the like with the lapse of use time, or the pitch of the diffraction grating is partially or entirely changed, and thus mechanical long-term stability is lost. Therefore, since the error included in the measurement value increases with the lapse of the use time, it is necessary to perform correction. At this time, the Y-axis interferometer 16 and the X-axis interferometer 126 in fig. 2 can measure the Y-position and the X-position of the wafer table WTB without Abbe (Abbe) error.

Therefore, can be ignoredThe measurement value of the X-axis interferometer 126 is fixed to a predetermined value at a low speed of short-term fluctuation of the measurement value of the Y-axis interferometer 16 due to the interferometer shake, and the Y-axis interferometer 16 and the Z sensor 74 in fig. 4 are used as the basis_1,4,74_2,4,76_1,3,76_2,3While maintaining all of the pitch, roll, and yaw at zero, wafer stage WST is moved in the + Y direction until, for example, Y scale 39Y₁,39Y₂Until the other ends (one end on the Y side) of the respective head units 62A and 62C coincide with each other (within the effective stroke range described above). In this movement, the main control device 20 captures the measurement values of the Y linear encoders 70A,70C and the measurement value of the Y-axis interferometer 16 of fig. 7 at predetermined sampling intervals, and obtains the relationship between the measurement values of the Y linear encoders 70A,70C and the measurement value of the Y-axis interferometer 16 according to the captured measurement values. And corrects errors in the measurement values of the Y linear encoders 70A,70C (the head units 62A,62C) based on the correlation.

Likewise, the X-axis interferometer 126 may be used to correct errors in the measurements of the X linear encoders 70B,70D (readhead units 62B, 62D).

Next, in step 207, the alignment and wafer exposure are performed by switching the measurement values of Y head 64 and X head 66 (encoder heads) of the plurality of X-axis and Y-axis head units 62A to 62D, and controlling the position and speed of wafer stage WST while measuring the coordinate position of wafer stage WST. Thereafter, the next step such as reticle replacement is performed in step 208.

Specifically, the wafer alignment in step 207 performed by the exposure apparatus 100 according to the present embodiment is briefly described with reference to fig. 10A to 10C.

Here, an operation will be described in which sixteen colored irradiation regions AS on the wafer W having a plurality of irradiation regions formed thereon are set AS the alignment irradiation regions in the arrangement (irradiation pattern) shown in fig. 10C. Fig. 10A and 10B are drawings in which measurement stage MST is omitted.

At this time, the alignment systems AL1 and AL2 of FIG. 4 are used in advance₁～AL2₄Measuring the measurements of FIG. 6AThe coordinates of the corresponding reference marks M on the CD bar 46 on the stage MST side are used to determine the alignment systems AL1 and AL2₁～AL2₄The baseline amount (the positional relationship between the coordinates of the detection center and the reference position of the pattern image of the reticle R in fig. 1) of (a) is stored in the alignment calculation system 20a in fig. 7. It is also premised that the second alignment system AL2₁～AL2₄The position in the X direction is adjusted in advance in accordance with the arrangement of the alignment irradiation region AS.

First, main controller 20 moves wafer stage WST, whose center is positioned at loading position LP, toward the upper left in fig. 10A, and positions it at a predetermined position (alignment start position described later) where the center of wafer W is positioned on straight line LV. The movement of wafer stage WST at this time is performed by main control device 20 driving the motors of stage drive system 124 based on the measurement values of X encoder 70D and Y-axis interferometer 16. In a state of being positioned at the alignment start position, the position (including the θ z rotation) of the wafer table WTB on which the wafer W is mounted in the XY plane is controlled based on the X scale 39X respectively facing the X scale of fig. 4₁,39X₂The measurement values of the two heads 66 provided in the head unit 62D and the measurement values of the two heads facing the Y scale 39Y₁,39Y₂Y head 64Y of₂,64y₁Measurements of (four encoders).

Next, main controller 20 moves wafer stage WST in the + Y direction by a predetermined distance based on the measurement values of the four encoders to position it at the position shown in fig. 10A, using first alignment system AL1 and second alignment system AL2₂,AL2₃The alignment marks (see the star marks in fig. 10A) attached to the three first alignment shot areas AS are simultaneously and individually detected, and the three alignment systems AL1 and AL2 are used₂,AL2₃The detection result of (a) and the measurement values of the above four encoders at the time of the detection are supplied to the alignment arithmetic system 20a in such a manner as to be associated with each other. In addition, the second alignment system AL2 for not detecting both ends of the alignment mark at this time₁,AL2₄The wafer table WTB (or the wafer) may be irradiated with or without irradiation with the detection light. Further, this embodimentIn the wafer alignment state, the position of wafer stage WST in the X direction is set so that first alignment system AL1 is disposed on the center line of wafer table WTB, and first alignment system AL1 detects alignment marks of the alignment irradiation area located on the center line of the wafer. Note that, although the alignment mark may be formed inside each irradiation region on the wafer W, in the present embodiment, the alignment mark is formed outside each irradiation region, that is, on a block boundary (scribe line) that divides a plurality of irradiation regions of the wafer W.

Next, main controller 20 moves wafer stage WST in the + Y direction by a predetermined distance based on the measurement values of the four encoders, and positions it so that it can use five alignment systems AL1 and AL2₁～AL2₄The positions of the alignment marks of the five second alignment shot areas AS attached to the wafer W are simultaneously and individually detected, and the five alignment systems AL1 and AL2 are used₁～AL2₄The detection result of (a) and the measurement values of the above four encoders at the time of the detection are supplied to the alignment arithmetic system 20a in such a manner as to be associated with each other.

Next, main controller 20 moves wafer stage WST in the + Y direction by a predetermined distance based on the measurement values of the four encoders, and positions it so that it can use five alignment systems AL1 and AL2₁～AL2₄The positions of the alignment marks of the five third alignment shot areas AS attached to the wafer W are simultaneously and individually detected, and then five alignment systems AL1, AL2 are used₁～AL2₄Five alignment marks (see star marks in FIG. 10B) are detected simultaneously and individually, and the five alignment systems AL1 and AL2 are used₁～AL2₄The detection result of (a) and the measurement values of the above four encoders at the time of the detection are supplied to the alignment arithmetic system 20a in such a manner as to be associated with each other.

Next, main controller 20 moves wafer stage WST in the + Y direction by a predetermined distance based on the measurement values of the four encoders, and positions wafer stage WST so that first alignment system AL1 and second alignment system AL2 can be used₂,AL2₃Three first alignment shot regions attached to the wafer W are simultaneously and individually detectedThe position of the alignment mark of AS, and the three alignment systems AL1, AL2₂,AL2₃Simultaneously and individually detecting three alignment marks and aligning the three alignment systems AL1 and AL2₂,AL2₃The detection result of (a) and the measurement values of the above four encoders at the time of the detection are supplied to the alignment arithmetic system 20a in such a manner as to be associated with each other.

Then, the alignment computing system 20a uses the detection results of the sixteen alignment marks obtained in the above manner and the corresponding measurement values of the four encoders, and the first and second alignment systems AL1 and AL2_nThe base line of (a) is statistically calculated by, for example, the EGA method disclosed in japanese patent application laid-open No. 61-44429 (corresponding to U.S. Pat. No. 4,780,617), and the like, and the arrangement of all the irradiation regions on the wafer W on a stage coordinate system (for example, an XY coordinate system with the optical axis of the projection optical system PL as the origin) defined by the measurement axes of the four encoders (four head units) is calculated.

In this way, in the present embodiment, by moving wafer stage WST in the + Y direction and positioning wafer stage WST at four positions on the movement path, it is possible to obtain the positional information of alignment irradiation areas AS for the total of sixteen alignment marks in a shorter time, AS compared with the case where sixteen alignment irradiation areas AS are detected in order by a single alignment system. In this case, in particular, for example, the alignment systems AL1, AL2₂,AL2₃It can be easily seen that these alignment systems AL1, AL2₂,AL2₃A plurality of alignment marks arranged in the Y-axis direction and sequentially arranged in a detection region (corresponding to, for example, an irradiation region of detection light) are detected in association with the movement of wafer stage WST. Therefore, when the alignment mark is measured, it is not necessary to move wafer stage WST in the X direction, and therefore, alignment can be performed efficiently.

Next, under the control of main controller 20, wafer stage WST is driven using the measurement values of head units 26A to 62D (encoders 70A to 70D) based on the array coordinates supplied from alignment arithmetic system 20A, and the pattern image of reticle R is exposed to all the irradiation regions on wafer W by the liquid immersion method and the step-and-scan method.

The operation and effect of the present embodiment are as follows.

(1) In the measurement method of exposure apparatus 100 of fig. 1, scale 39X provided on wafer stage WST (movable member) is detected by a plurality of X heads 66 and Y heads 64₁,39X₂And 39Y₁,39Y₂A method for measuring displacement information of a wafer stage WST includes: step 201 is a step of supporting a plurality of X heads 66 and Y heads 64 by measurement frame 21, and measuring frame 21 has a linear expansion coefficient smaller than that of scale 39X formed on wafer stage WST₁The linear expansion coefficient of the body portion other than the plate body 28 is small; and step 207 of measuring displacement information of wafer stage WST from the detection results of X head 66 and Y head 64.

The exposure apparatus 100 is an exposure apparatus that irradiates illumination light IL (exposure light) to a wafer W held on a movable wafer stage WST to form a predetermined pattern on the wafer W, and includes: the scale 39X₁,39Y₁Etc.; a plurality of X heads 66 and Y heads 64 for detecting position information of the scale; a measurement frame 21 that integrally supports a plurality of X heads 66 and Y heads 64; and switching control units 70Aa to 70Da in encoders 70A to 70D for obtaining displacement information of wafer stage WST from the detection results of plurality of X heads 66 and Y heads 64.

Since X head 66 and Y head 64 detect the scale provided on wafer stage WST as described above, the influence of the refractive index variation of the ambient gas can be reduced without providing an optical path having the same length as the movement stroke of the movable member as in the case of a laser interferometer. Further, when the scale 39X₁When the scale is separated from the detection target region of one X head 66, the scale 39X can be switched to be detected₁And other X read heads 66 are measuring in parallel. At this time, the linear expansion coefficient of measurement frame 21 is smaller than the main body of wafer stage WST, and even if the ambient temperature fluctuates, the fluctuation in the positional relationship between plurality of X heads 66 can be suppressed, and the cut can be reducedMeasurement error when changing the plurality of X read heads 66. Therefore, the positioning accuracy of wafer stage WST, the overlay accuracy of the exposure apparatus, and the like can be improved.

(2) The measuring frame 21 is made of a material having a smaller linear expansion coefficient than the factor steel. Therefore, even if a temperature change occurs to some extent in the measurement frame 21, the measurement error can be kept small. The measuring frame 21 may be formed by connecting a plurality of blocks by screws or the like.

(3) Further, step 202 is provided in which measuring frame 21 is supported by vibration isolation members 23A to 23C so as to be separated from each other with respect to the floor surface, and further, with respect to fixed base 12 having the guide surface of wafer stage WST. Therefore, measurement errors of X head 66 and Y head 64 due to the influence of vibration when wafer stage WST is driven do not occur.

(4) Further, a step 205 is provided for suppressing displacement of measurement frame 21 with respect to the floor surface and further with respect to fixed base 12 having the guide surface of wafer stage WST, using sensors 106XA to 106ZC and actuators 107XA to 107ZC in fig. 3. Therefore, even if the measurement frame 21 is supported by the vibration-proof member, the X head 66 and the Y head can be stably maintained, and the measurement accuracy can be improved.

(5) Further, a step 206 is provided in which X-axis interferometer 16 and X-axis interferometer 126, which are at least some of the optical components of the wafer interferometer, are provided on measurement frame 21, and the displacement of wafer stage WST with respect to measurement frame 21 (projection optical system PL) is measured by Y-axis interferometer 16 and X-axis interferometer 126. Therefore, the measurement values of Y head 64 and X head 66 can be corrected by the measurement values of Y-axis interferometer 16 and X-axis interferometer 126.

(6) Further, a scale 39X₁,39Y₁The X head 66 and the Y head 64 are diffraction grating-like periodic patterns, and irradiate the periodic patterns with detection light and receive interference light of a plurality of diffracted lights (1 st-order diffracted light) generated from the periodic patterns. Therefore, not only can the influence of wobble be reduced by using short optical paths for X head 66 and Y head 64, but also the position of wafer stage WST can be measured with the level analysis capability (accuracy) of the laser interferometerAnd (6) moving.

As the encoders 70A to 70D, a magnetic linear encoder or the like including a periodic magnetic scale (a magnet body having polarity reversal formed at a fine pitch) and a magnetic head for reading the magnetic scale can be used.

[ embodiment 2 ]

Embodiment 2 of the present invention will be described below with reference to fig. 12. In the present embodiment, X head 66 and the like in fig. 1 are not directly supported by the measurement frame, but are supported by a member engaged with the measurement frame. In fig. 12, the same or similar reference numerals are given to portions corresponding to those in fig. 1, and detailed description thereof will be omitted or simplified.

Fig. 12 shows an exposure apparatus 100A according to the present embodiment. In fig. 12, instead of the measurement frame 21 of fig. 1, a flat plate-shaped measurement frame 21M is suspended and supported by suspension members 22A,22B and the like through vibration-proof members 23A,23B and the like. A flat-plate-shaped encoder head holder (hereinafter referred to as a head holder) 26 is vacuum-sucked and held on the bottom surface of the measurement frame 21M. A plurality of openings (not shown) through which the gas supplied by the downflow passes are formed in the measurement frame 21M and the head base 26 so as to be in substantially the same positional relationship in the XY plane. Further, openings 21Ma and 26a through which the lower end of the projection unit PU passes are formed in the measurement frame 21M and the head base 26, respectively.

Further, a plurality of X heads 66 constituting head units 62B,26D of fig. 4 and a plurality of Y heads 64 (not shown in fig. 12) constituting head units 62A,26C of fig. 4 are fixed to the bottom surface of head base 26 by fixing members (not shown). The Y-axis interferometers 16,18 and the X-axis interferometers 126,130 of FIG. 2 are also fixed to the bottom surface of the readhead mount 26. In addition, the alignment systems AL1, AL2 of FIG. 4₁～AL2₄May also be supported by the metrology frame 21M, and alignment systems AL1, AL2 may be provided on the readhead mount 26₁～AL2₄The front end portion of (a). Also, alignment systems AL1, AL2 can be used₁～AL2₄Is supported by the head base 26.

Also, in the crystal of FIG. 12As in fig. 5, X scale 39X is formed on plate 28 of wafer stage WST₁,39X₂And Y scale 39Y₁,39Y₂. X head 66 and Y head 64 (not shown) on the bottom surface of head base 26 in fig. 12 also detect X scale 39X₁,39X₂And Y scale 39Y₁,39Y₂And further detects the position information of wafer stage WST (wafer table WTB).

In fig. 12, head base 26 is a plate 28 (on which scale 39X in fig. 5A is formed) having a coefficient of linear expansion smaller than that of wafer stage WST₁,39X₂,39Y₁,39Y₂) The other members (the main body of wafer stage WST) are made of a material having a small linear expansion coefficient, that is, a material having a very small linear expansion coefficient. The material of the head base 26 is a low expansion glass or a low expansion glass ceramic, which is the same as the measuring frame 21 of fig. 1. Since the head base 26 is small and has a thickness of about a fraction of the thickness of the measuring frame 21M, the head base 26 can be easily formed using low-expansion glass or low-expansion glass ceramic.

The frame 21M of FIG. 12 is made of a material having a linear expansion coefficient larger than that of the head base 26 and smaller than that of a metal such as iron, for example, a material having a linear expansion coefficient of 1 × 10^-6A factor of about/K is formed for steel. By using the above-described material, the large-sized measurement frame 21M can be easily formed integrally. In addition, the measurement frame 21M is also provided with six-axis sensors 106XA to 106ZC and six-axis actuators 107XA to 107ZC in the same manner as the measurement frame 21 of fig. 3, whereby control can be performed so that the displacement with respect to the ground surface is within an allowable range.

Vacuum pads 111A,111B are provided at a plurality of positions on the bottom surface of the measurement frame 21M, and the vacuum pads 111A,111B and the like are connected to an adsorption device 110 including an air compressor and a vacuum pump through pipes 112A,112B and the like. The head base 26 is held on the bottom surface of the measuring frame 21M by a vacuum pre-press type aerostatic bearing system via an air layer G having a thickness of about several μ M so as to be smoothly movable in the XY plane (substantially horizontal plane in the present embodiment) by pressurization and negative pressure from the adsorption device 110.

However, in order to prevent the position of the head base 26 from gradually changing, the head base 26 is connected to the measurement frame 21M in a rotatable state by the bolt 109A at a measurement reference position. Further, the head base 26 is connected to the measurement frame 21M at a position substantially symmetrical to the projection optical system PL at its reference position in a state of being relatively movable in the direction of the straight line of the connection bolts 109A,109B by the bolts 109B through the long holes formed in the head base 26. The other structure is the same as that of embodiment 1 of fig. 1.

According to this embodiment, the following operational effects can be exhibited in addition to embodiment 1.

(1) In the present embodiment, a plurality of X heads 66 and the like, Y-axis interferometers 16 and 18 and the like are attached to the bottom surface of the head base 26 in a step corresponding to step 201 in fig. 11. Subsequently, head base 26 is a plate body 28(X scale 39X) that can be moved along wafer stage WST₁,39X₂Etc.) is connected to the measurement frame 21M (base member) having a linear expansion coefficient larger than that of the head base 26 via the vacuum pads 111A,111B, etc.

Therefore, the measurement frame 21M and the head rest 26 can be easily formed of materials having low coefficients of expansion. Further, it is assumed that the difference in length between the measurement frame 21M and the head rest 26 is caused by a slight temperature change due to the difference in linear expansion coefficient therebetween. In this case, since the head base 26 can be smoothly displaced along the plate body 28 (the measuring frame 21M) centering on the bolt 109A, the head base 26 can be free from twisting due to the bimetal effect. Therefore, the position of wafer stage WST can be measured at any time with high accuracy by X head 66 and the like.

(2) The head base 26 is connected to the measurement frame 21M by vacuum pads 111A,111B (gas bearings) in a state where the position of the bolt 109A (predetermined reference position) does not relatively displace. Therefore, the position of the head base 26 does not change gradually.

(3) Head base 26 is connected to measurement frame 21M so as to be displaceable in the direction of connection bolts 109A and 109B. Thus, the readhead mount 26 does not rotate gradually.

Instead of the bolts, the head base 26 may be connected to the measurement frame 21M in a displaceable manner by using leaf springs or the like.

[ embodiment 3 ]

Embodiment 3 of the present invention will be described below with reference to fig. 13 to 15. In the present embodiment, the head base 26 is not connected to the measurement frame 21M by a gas bearing as in the embodiment of fig. 12, but is connected by a simpler flexure mechanism. In fig. 13 to 15, the same reference numerals are given to portions corresponding to fig. 12, and detailed description thereof will be omitted.

Fig. 13 shows an exposure apparatus 100B according to the present embodiment. In fig. 13, the head base 26 to which the X heads 66 and the like are fixed can be mounted along the plate body 28 (on the X scale 39X in fig. 5 a) by a plurality of rod-like flexure members 113 arranged at substantially predetermined intervals in the X direction and the Y direction₁,39X₂Etc.) is connected to the bottom surface of the measuring frame 21M in a state where the surface is displaced in the direction. In other words, the distal ends (the ends on the head base 26 side) of the plurality of rod-like flexure members 113 are elastically deformable along the X-axis 39X₁,39X₂Etc. are displaced in equal directions.

Fig. 14 is an enlarged perspective view showing a part of the measurement frame 21M and the head base 26 of fig. 13. As shown in fig. 14, the flexure member 113 is a rod-shaped member in which circumferential notches (grooves) 113a and 113b are formed at both ends, and which can be easily deformed at both ends. Further, a plurality of openings 25M and 25 through which the gas supplied by the down flow passes are formed in the measurement frame 21M and the head base 26. The other structure is the same as the embodiment of fig. 12.

In the present embodiment, the measurement frame 21M and the head rest 26 are coupled to each other in a state capable of absorbing deformation due to a difference in linear expansion coefficient by using the flexure member 113 having a simple mechanism, instead of using a complicated mechanism such as a vacuum suction mechanism. The linear expansion coefficient of the head rest 26 is smaller than that of the measurement frame 21M. At this time, it is assumed that the state of fig. 15A is changed to a state where the measurement frame 21M is extended more than the head base 26 as shown in fig. 15B due to a temperature change due to a difference in linear expansion coefficient between the two. Even in this case, the elastic deformation of the plurality of flexure members 113 can minimize the deformation of the head base 26 (and hence the change in the positional relationship of the plurality of X heads 66 and the like). Therefore, even if the measurement values of X head 66 and the like in fig. 13 are switched, the positional information of wafer stage WST can be measured with high accuracy.

Further, since the linear expansion coefficient of the measurement frame 21M is larger than that of the head rest 26, a material such as steel, which is easily formed into a large member, can be used, and thus the manufacturing is easy. In embodiment 3, the coefficient of linear expansion of the body of wafer stage WST may be about the same as or less than the coefficient of linear expansion of head rest 26.

In the present embodiment, instead of the flexure member 113, a long and thin rod-shaped member (flexure member with a simple structure) 114 shown in fig. 16A, a flexure member 115 shown in fig. 16B having grooves 115a and 115B along the X-direction and the Y-direction of fig. 13 formed at both ends, and the like may be used.

As shown in the plan view of fig. 17, the measurement frame 21M and the head rest 26 may be connected by a plurality of plate springs 131 substantially parallel to the YZ plane and arranged to sandwich the projection unit PU in the X direction, a plurality of plate springs 132 substantially parallel to the XZ plane and arranged to sandwich the projection unit PU in the Y direction, and flexure members 113 arranged substantially uniformly in the other portions. Thereby, the head base 26 can be more stably connected to the measurement frame 21M.

In the above embodiment, scale 39X is fixed to wafer stage WST side₁,39Y₁The heads 64,66 of the encoder are fixed to the measurement frame 21 and the like. However, as shown in another embodiment of fig. 19, heads 64 and 66 of the encoder may be fixed to wafer stage WST side, and X scales 39AX1 and 39AX2 may be fixed to measurement frame 21S.

That is, in the exposure apparatus 100C of fig. 19, the flange portion 40F of the lens barrel of the projection unit PU (projection optical system PL) is held by a main frame (not shown), and a flat plate-shaped measurement frame 21S having an opening formed at the center thereof through which the projection unit PU passes is fixed to the bottom surface of the flange portion 40F. The measurement frame 21S is formed of a material having a small linear expansion coefficient, similarly to the measurement frame 21. On the bottom surface of the measurement frame 21S, a pair of rectangular flat plate-like X scales 39AX1,39AX2 having a grid with a predetermined pitch formed in the X direction are arranged so as to sandwich the projection unit PU in the Y direction.

As shown in fig. 20, which is a bottom view along the AA line in fig. 19, a pair of Y scales 39AY1,39AY2, each having a grid with a predetermined pitch formed in the Y direction, are disposed on the bottom surface of the measurement frame 21S so as to sandwich the projection unit PU in the X direction. The X scales 39AX1 and 39AX2 and the Y scales 39AY1 and 39AY2 are covered with flat plate-like cover glasses 132A,132B,132C, and 132D having substantially the same shape. These cover glasses 132A to 132D are held by the measuring frame 21S by elastic force of a degree of movement of the scales 39AX1,39AX2,39AY1,39AY2 due to thermal deformation by the plurality of mounting members 133 and 134. Further, taking lines passing through the optical axis AX (exposure center) of the projection unit PU and parallel to the X axis and the Y axis as LH and LV, the vacuum pads 111G,111H are provided on the Y scales 39AY1,39AY2 along the line LH, and the vacuum pads 111E,111F are provided on the X scales 39AX1,39AX2 along the line LV.

The vacuum pads 111E to 111H are connected to the suction device 110A including a vacuum pump through a vent hole in the measurement frame 21S and pipes 112E and 112F in fig. 19, respectively. In the exposure, the scales 39AX1,39AX2,39AY1,39AY2 are sucked from the suction device 110A to the measurement frame 21S side through the vacuum pads 111E to 111H. Thus, the scales 39AX1,39AX2,39AY1, and 39AY2 are fixed by the vacuum pads 111E to 111H, and highly accurate position measurement can be performed with the projection unit PU as a reference without being separated from the exposure center. Further, instead of the vacuum pads 111E to 111H, means (for example, bolts in embodiment 2) for mechanically fixing the measuring frame 21S and the scales 39AX1,39AX2,39AY1,39AY2 may be provided.

For example, in embodiment 3, scales 39AX1,39AX2,39AY1, and 39AY2 may be connected by a flexure mechanism as shown in fig. 14 to 16.

A pair of detection frames 135A,135B extending in the Y direction are fixed to the stage main body 91 sandwiching the wafer stage WST in the Y direction, a pair of detection frames 135C,135D (135D not shown) extending in the X direction are fixed to the stage main body 91 sandwiching the X direction, a plurality of X heads 66 for detecting X scales 39AX1,39AX2 are fixed to the detection frames 135A,135B at predetermined intervals, and a plurality of Y heads 64 for detecting Y scales 39AY1,39AY2 are fixed to the detection frames 135C,135D at predetermined intervals. Even when wafer stage WST moves in the X direction and the Y direction, the positions of wafer stage WST can be measured with high accuracy by switching these plurality of X heads 66 and Y heads 64 to detect scales 39AX1,39AX2,39AY1, and 39AY 2. The detection frames 135A to 135D are preferably formed of a material having an extremely small coefficient of linear expansion, such as super factor steel.

In addition, when a microdevice such as a semiconductor device is manufactured using the exposure apparatus according to the above embodiment, the microdevice can be manufactured by, for example, a process shown in fig. 18, which includes: a step 221 of designing the functions and performances of the microdevice, a step 222 of fabricating a mask (reticle) based on the designing step, a step 223 of fabricating a substrate as a base material of the device, a substrate processing step 224 including a step of exposing the pattern of the reticle to the substrate by the exposure apparatus 100 (projection exposure apparatus) of the above-described embodiment, a step of developing the exposed substrate, a step of heating (CURE) and etching the developed substrate, a device assembling step (a processing program including a dicing step, a bonding step, a packaging step, and the like) 225, an inspection step 226, and the like.

In other words, the device manufacturing method includes a lithography process in which the exposure apparatus according to the above-described embodiment is used. In this case, even if the wafer stage is moved at a high speed, the position of the wafer stage can be measured with high accuracy by the encoder even if the wafer stage is moved at a high speed and even if a temperature fluctuation occurs to some extent.

The present invention is applicable to a projection exposure apparatus (such as a stepper) of a step-and-repeat system, a machine tool, and the like, in addition to the above-described projection exposure apparatus (scanner) of a step-and-scan system of a scanning exposure type. The present invention is also applicable to dry exposure apparatuses other than the liquid immersion exposure apparatus.

The present invention is not limited to an exposure apparatus for manufacturing a semiconductor device, and can be applied to an exposure apparatus for transferring an element pattern onto a glass plate for manufacturing a display including a liquid crystal display element, a plasma display, or the like, an exposure apparatus for transferring an element pattern onto a ceramic wafer for manufacturing a thin film magnetic head, and an exposure apparatus for manufacturing an imaging element (CCD or the like), an organic EL, a micromachine, a mems (micro electro mechanical systems), a DNA chip, or the like. In addition to the production of microdevices such as semiconductor devices, the present invention can be applied to an exposure apparatus for transferring a circuit pattern to a glass substrate, a silicon wafer, or the like in order to produce a mask used in a light exposure apparatus or an EUV (extreme ultraviolet) exposure apparatus.

As described above, the present invention is not limited to the above-described embodiments, and various configurations can be obtained within a range not departing from the gist of the present invention.

Further, all the disclosures of Japanese patent application No. 2007-187649, which are filed on 2007/18/2007 including the specification, the claims, the drawings, and the abstract, are incorporated herein by reference in their entirety.

Claims (8)

1. A measurement method for measuring the displacement information of a carrier relative to a predetermined member, comprising:

a step of providing a scale on the predetermined member, and providing a plurality of detectors capable of detecting the scale on the stage;

a step of supporting the scale provided on the predetermined member by a supporting member having a smaller linear expansion coefficient than the stage;

connecting the support member to a base member in a state of being displaceable in a direction along the scale surface; and

measuring displacement information of the stage from the detection results of the plurality of detectors;

the predetermined member has the base member having a linear expansion coefficient larger than that of the support member.

2. The method of claim 1, wherein the support member has a coefficient of linear expansion less than that of steel.

3. A method of measuring according to claim 1, wherein the scale is coupled to the base member by a plurality of flexure members having a tip portion displaceable in a direction along the surface of the scale.

4. A stage device capable of positioning a stage with respect to a predetermined member, comprising:

a scale provided on the predetermined member;

a plurality of detectors arranged on the carrier for detecting information related to the position of the scale;

a support member which supports the scale provided on the predetermined member and has a linear expansion coefficient smaller than that of the stage;

a coupling mechanism that couples the support member to the base member in a state of being displaceable in a direction along the scale surface; and

a control device for obtaining displacement information of the stage from the detection results of the plurality of detectors;

the predetermined member has the base member having a linear expansion coefficient larger than that of the support member.

5. The stage apparatus of claim 4, wherein the support member has a coefficient of linear expansion that is less than that of steel.

6. The stage apparatus of claim 4, wherein the coupling mechanism comprises a plurality of flexure members that couple the scale and the base member and have front ends that are displaceable in a direction along the surface of the scale.

7. An exposure apparatus, characterized in that, a substrate is irradiated with exposure light to form a predetermined pattern on the substrate;

having a stage apparatus according to any of claims 4 to 6 by means of which the substrate is positioned.

8. A method of fabricating a device comprising a lithographic process, the method comprising:

the exposure apparatus of claim 7 is used in the photolithography process.