JP5211690B2 - Calibration method, moving body driving method and apparatus, exposure method and apparatus, pattern forming method and apparatus, and device manufacturing method - Google Patents

Description

  The present invention relates to a calibration method, a moving body driving method and apparatus, an exposure method and apparatus, a pattern forming method and apparatus, and a device manufacturing method, and more specifically, calibrates the accuracy of driving a moving body along a predetermined plane. Calibration method, moving body driving method and apparatus for driving the moving body along a predetermined plane by introducing the calibration method, exposure method using the moving body driving method, and exposure apparatus including the moving body driving device, The present invention relates to a pattern forming method using the moving body driving method, a pattern forming apparatus including the moving body driving device, and a device manufacturing method using the pattern forming method.

  Conventionally, in a lithography process for manufacturing electronic devices (microdevices) such as semiconductor elements (integrated circuits, etc.), liquid crystal display elements, etc., a step-and-repeat reduction projection exposure apparatus (so-called stepper), A reduction projection exposure apparatus (a so-called scanning stepper (also called a scanner)) is used.

  In these exposure apparatuses, in order to transfer a pattern of a reticle (or mask) to a plurality of shot areas on a substrate such as a wafer or a glass plate (hereinafter collectively referred to as a wafer), a wafer stage that holds the wafer includes, for example, It is driven in a two-dimensional direction by a linear motor or the like. The position of the wafer stage is generally measured by using a laser interferometer having high stability over a long period of time.

  However, in recent years, with the miniaturization of patterns due to higher integration of semiconductor elements, the requirement for overlay accuracy has become stricter, and air fluctuations caused by the temperature change and temperature gradient of the atmosphere on the beam optical path of the laser interferometer. Short-term fluctuations in measurement values due to occupy a large weight in the overlay budget.

  Therefore, the applicant has adopted an exposure apparatus that employs an encoder that has a measurement resolution comparable to or higher than that of a laser interferometer and is generally less susceptible to air fluctuations than an interferometer as a wafer stage position measurement device. Previously proposed (see, for example, Patent Document 1).

  However, in the exposure apparatus disclosed in Patent Document 1, the movement stroke of the wafer stage is set to be long in the direction (Y-axis direction) parallel to the straight line connecting the optical axis of the projection optical system and the detection center of the alignment system. Yes. In addition, a pair of scales (diffraction gratings) are provided on one side and the other side of the upper surface of the wafer stage with respect to the Y-axis direction, and a pair of encoder head units corresponding to the Y-axis direction are arranged separately with respect to the Y-axis direction. Configuration is adopted. Therefore, in the exposure apparatus disclosed in Patent Document 1, the head unit (head) is switched according to the position of the wafer stage in the Y-axis direction, but whichever head is used, It is necessary to obtain the same measurement result regardless of the scale used.

International Publication No. 2007/097379 Pamphlet

From a first aspect, the present invention is a calibration method for calibrating the accuracy of driving a moving body along a predetermined plane, wherein the moving body is moved in a first direction parallel to one axis in the predetermined plane. driven to, the first and second gratings, a pair of encoder heads that face each of the first direction provided in substantially one surface parallel to the predetermined plane of the movable body and the periodic direction, the first Measuring the position of the moving body in one direction; and creating calibration data for calibrating at least one measurement value of the pair of encoder heads based on the measurement result of the pair of encoder heads. Calibration method.

According to this, since the position of the moving body is measured by the pair of encoder heads respectively facing the first and second gratings, the measurement error caused by the first and second gratings is included from each of the pair of encoder heads. A measurement result is obtained. Therefore, calibration data for calibrating at least one measurement value of the pair of encoder heads is created based on the measurement result of the pair of encoder heads. Then, using the created calibration data, the measurement value of the encoder head facing at least one of the first and second gratings is calibrated, thereby driving the moving body based on the measurement result of the encoder head facing the first grating. It is possible to match the system with the driving accuracy of the moving body based on the measurement result of the encoder head facing the second grating.

  According to a second aspect of the present invention, there is provided a moving body driving method for driving a moving body along a predetermined plane, wherein the predetermined plane is provided on one surface of the moving body substantially parallel to the predetermined plane. Using at least one of the first and second head units each having a plurality of first and second encoder heads that can be opposed to the first and second gratings having a first direction parallel to one of the axes as a periodic direction. Measuring the position of the moving body with respect to the first direction; driving the moving body based on the measurement result of the measuring step and the calibration data created using the calibration method of the present invention. A moving body driving method including:

  According to this, the measurement result of the position of the moving body in the first direction measured using at least one of the first and second head units and the calibration data created using the calibration method of the present invention. Based on this, the moving body is driven. Therefore, using the calibration data, it is possible to calibrate the measurement result including the measurement error due to the grating of at least one of the first and second head units. Thereby, the case where the first head unit composed of the first encoder head facing the first grating is used, and the case where the second head unit composed of the second encoder head facing the second grating are used, and As a result, the measurement accuracy of the position measurement of the moving body becomes the same. Therefore, even when the encoder head is switched between the first and second head units and used, it is possible to always maintain the same driving accuracy of the moving body.

  According to a third aspect of the present invention, there is provided an exposure method for forming a pattern on an object by irradiating an energy beam, wherein the moving body driving method of the present invention is used to form the pattern. An exposure method includes a step of driving a moving body that holds an object.

  According to this, in order to form the pattern on the object by irradiating the energy beam, the moving body holding the object is driven using the moving body driving method of the present invention. Therefore, it becomes possible to form a pattern on the object with high accuracy.

  According to a fourth aspect of the present invention, there is provided a pattern forming method for forming a pattern on an object, wherein the object is held by using the moving body driving method of the present invention to form the pattern. It is a pattern formation method including the process of driving a body along a predetermined plane.

  According to this, in order to form a pattern on the object, the moving body holding the object is driven using the moving body driving method of the present invention. This makes it possible to form a pattern on the object with high accuracy.

  According to a fifth aspect of the present invention, there is provided a device manufacturing method comprising: a step of forming a pattern on an object using the pattern forming method of the present invention; and a step of processing the object on which the pattern is formed. Is the method.

  According to a sixth aspect of the present invention, there is provided a moving body driving apparatus that drives a moving body along a predetermined plane, the predetermined plane provided on one surface of the moving body substantially parallel to the predetermined plane. A plurality of first and second encoder heads that can face the first and second gratings each having a first direction parallel to one of the axes as a periodic direction, and measuring the position of the moving body in the first direction The first and second head units; a storage device for storing calibration data created using the calibration method of the present invention; and the moving body obtained by using at least one of the first and second head units. A driving device that drives the moving body based on a position measurement result and the calibration data.

  According to this, the driving device measures the position of the moving body in the first direction measured using at least one of the first and second head units, and the calibration created using the calibration method of the present invention. The mobile body is driven based on the data. Therefore, using the calibration data, it is possible to calibrate the measurement result including the measurement error due to the grating of at least one of the first and second head units. Thereby, the case where the 1st head unit comprised from the 1st encoder head which opposes the 1st grating is used, and the case where the 2nd head unit comprised from the 2nd encoder head which opposes the 2nd grating is used. As a result, the measurement accuracy of the position measurement of the moving body, and hence the drive accuracy, coincide. Therefore, even when the encoder head is switched between the first and second head units and used, it is possible to always maintain the same driving accuracy of the moving body.

  According to a seventh aspect of the present invention, there is provided an exposure apparatus for irradiating an energy beam to form a pattern on an object, wherein a moving body that holds the object is arranged along a predetermined plane in order to form the pattern. It is an exposure apparatus provided with the moving body drive device of the present invention.

  According to this, in order to form the pattern on the object by irradiating the energy beam, the moving body holding the object is driven along a predetermined plane using the moving body driving apparatus of the present invention. Therefore, it becomes possible to form a pattern on the object with high accuracy.

  According to an eighth aspect of the present invention, there is provided a pattern forming apparatus for forming a pattern on an object, the movable body being movable while holding the object; a pattern generating apparatus for forming a pattern on the object; And a moving body driving device of the present invention that drives the moving body along a predetermined plane.

  According to this, in order to form a pattern on the object, the moving body holding the object is driven along a predetermined plane using the moving body driving apparatus of the present invention. Thereby, it becomes possible to form a pattern on the object with high accuracy.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to FIGS.

  FIG. 1 schematically shows a configuration of an exposure apparatus 100 according to an embodiment. The exposure apparatus 100 is a step-and-scan projection exposure apparatus, a so-called scanner. As will be described later, in the present embodiment, the projection optical system PL and the primary alignment system AL1 are provided. In the following, the direction parallel to the optical axis AX of the projection optical system PL is the Z-axis direction, and the plane orthogonal to this. The direction parallel to the straight line connecting the optical axis AX and the detection center of the primary alignment system AL1 is the Y-axis direction, the direction orthogonal to the Z-axis and the Y-axis is the X-axis direction, and the X-axis, Y-axis, and Z-axis directions are The rotation (tilt) direction will be described as θx, θy, and θz directions, respectively.

  3 and 4, the reference axis LV parallel to the three reference axes in the XY plane, that is, the Y axis connecting the optical axis AX and the detection center of the primary alignment system AL1, the optical axis AX and the reference axis LV. A reference axis LH parallel to the X axis orthogonal to the reference axis LA and a reference axis LA parallel to the X axis orthogonal to the reference axis LV at the detection center of the alignment system AL1 are introduced.

  The exposure apparatus 100 includes an illumination system 10, a reticle stage RST, a projection unit PU, a local immersion apparatus 8, a stage apparatus 50 having a wafer stage WST and a measurement stage MST, and a control system thereof. The exposure apparatus 100 is configured in the same manner as the exposure apparatus disclosed as an embodiment of International Publication No. 2007/097379 pamphlet, except for a part. In FIG. 1, wafer W is placed on wafer stage WST.

  The illumination system 10 includes a light source, an illuminance uniformizing optical system including an optical integrator, a reticle blind, and the like (both not shown) as disclosed in, for example, US Patent Application Publication No. 2003/0025890. And an illumination optical system. The illumination system 10 illuminates the slit-shaped illumination area IAR on the reticle R defined by the reticle blind (masking system) with illumination light (exposure light) IL with substantially uniform illuminance. Here, as an example, ArF excimer laser light (wavelength 193 nm) is used as the illumination light IL.

  On reticle stage RST, reticle R having a circuit pattern or the like formed on its pattern surface (lower surface in FIG. 1) is fixed, for example, by vacuum suction. The reticle stage RST can be finely driven in the XY plane by a reticle stage drive system 11 (not shown in FIG. 1, refer to FIG. 7) including a linear motor, for example, and also in the scanning direction (left and right direction in FIG. 1). In the Y-axis direction) at a predetermined scanning speed.

  Position information within the moving plane of reticle stage RST (including rotation information in the θz direction) is transferred by reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 116 to moving mirror 15 (actually in the Y-axis direction). Through a Y-moving mirror (or retro reflector) having an orthogonal reflecting surface and an X moving mirror having a reflecting surface orthogonal to the X-axis direction), detection is always performed with a resolution of, for example, about 0.25 nm. Is done. The measurement value of reticle interferometer 116 is sent to main controller 20 (not shown in FIG. 1, refer to FIG. 7).

  Projection unit PU is arranged below reticle stage RST in FIG. The projection unit PU includes a lens barrel 40 and a projection optical system PL held in the lens barrel 40. As projection optical system PL, for example, a refractive optical system including a plurality of optical elements (lens elements) arranged along optical axis AX parallel to the Z-axis direction is used. The projection optical system PL is, for example, both-side telecentric and has a predetermined projection magnification (for example, 1/4 times, 1/5 times, or 1/8 times). For this reason, when the illumination area IAR on the reticle R is illuminated by the illumination system 10, the illumination light that has passed through the reticle R arranged so that the first surface (object surface) and the pattern surface of the projection optical system PL substantially coincide with each other. The reduced image of the circuit pattern of the reticle R in the illumination area IAR (a reduced image of a part of the circuit pattern) is passed through the projection optical system PL (projection unit PU) by the IL on the second surface (image surface) side. And is formed in an area IA (hereinafter also referred to as an exposure area) IA conjugate to the illumination area IAR on the wafer W having a surface coated with a resist (sensitive agent). The reticle stage RST and wafer stage WST are driven synchronously to move the reticle relative to the illumination area IAR (illumination light IL) in the scanning direction (Y-axis direction) and to the exposure area (illumination light IL). By moving the wafer W relative to the scanning direction (Y-axis direction), scanning exposure of one shot area (partition area) on the wafer W is performed, and a reticle pattern is transferred to the shot area. That is, in this embodiment, a pattern is generated on the wafer W by the illumination system 10, the reticle, and the projection optical system PL, and the pattern is formed on the wafer W by exposure of the sensitive layer (resist layer) on the wafer W by the illumination light IL. It is formed.

  The exposure apparatus 100 of the present embodiment is provided with a local liquid immersion apparatus 8 for performing immersion type exposure. The local liquid immersion device 8 includes a liquid supply device 5, a liquid recovery device 6 (both not shown in FIG. 1, refer to FIG. 7), a liquid supply tube 31A, a liquid recovery tube 31B, a nozzle unit 32, and the like. As shown in FIG. 1, the nozzle unit 32 holds an optical element on the most image plane side (wafer W side) constituting the projection optical system PL, here a lens (hereinafter also referred to as “tip lens”) 191. It is suspended and supported by a main frame (not shown) that holds the projection unit PU so as to surround the lower end portion of the lens barrel 40. In the present embodiment, as shown in FIG. 1, the lower end surface of the nozzle unit 32 is set substantially flush with the lower end surface of the front lens 191. Further, the nozzle unit 32 is connected to the supply port and the recovery port of the liquid Lq, the lower surface on which the wafer W is disposed and provided with the recovery port, and the supply connected to the liquid supply tube 31A and the liquid recovery tube 31B, respectively. A flow path and a recovery flow path are provided. As shown in FIG. 4, the liquid supply pipe 31 </ b> A and the liquid recovery pipe 31 </ b> B are inclined substantially 45 ° with respect to the X-axis direction and the Y-axis direction in plan view (viewed from above) and are symmetric with respect to the reference axis LV. It has become the arrangement.

  The liquid supply pipe 31A is connected to the liquid supply apparatus 5 (not shown in FIG. 1, see FIG. 7), and the liquid recovery pipe 31B is connected to the liquid recovery apparatus 6 (not shown in FIG. 1, see FIG. 7). Here, the liquid supply device 5 includes a tank for storing the liquid, a pressurizing pump, a temperature control device, a valve for controlling the flow rate of the liquid, and the like. The liquid recovery device 6 includes a tank for storing the recovered liquid, a suction pump, a valve for controlling the flow rate of the liquid, and the like.

  The main controller 20 controls the liquid supply device 5 (see FIG. 7) to supply liquid between the front lens 191 and the wafer W via the liquid supply pipe 31A. Then, the liquid recovery apparatus 6 (see FIG. 7) is controlled to recover the liquid from between the front lens 191 and the wafer W via the liquid recovery pipe 31B. At this time, the main controller 20 controls the liquid supply device 5 and the liquid recovery device 6 so that the amount of supplied liquid and the amount of recovered liquid are always equal. Accordingly, a certain amount of liquid Lq (see FIG. 1) is always exchanged and held between the front lens 191 and the wafer W, whereby the liquid immersion region 14 is formed. In addition, even when a measurement stage MST described later is positioned below the projection unit PU, the liquid immersion region 14 can be similarly formed between the tip lens 191 and the measurement table.

  In this embodiment, pure water that transmits ArF excimer laser light (light having a wavelength of 193 nm) (hereinafter, simply referred to as “water” unless otherwise required) is used as the liquid. Note that the refractive index n of water with respect to ArF excimer laser light is approximately 1.44, and the wavelength of the illumination light IL is shortened to 193 nm × 1 / n = about 134 nm in water.

  As shown in FIG. 1, the stage apparatus 50 includes a wafer stage WST and a measurement stage MST disposed above the base board 12, and a measurement system 200 (see FIG. 7) that measures positional information of both stages WST and MST. And a stage drive system 124 (see FIG. 7) for driving both stages WST and MST. As shown in FIG. 7, the measurement system 200 includes an interferometer system 118, an encoder system 150, a surface position measurement system 180, and the like.

  Wafer stage WST and measurement stage MST are supported above base board 12 by a non-contact bearing (not shown) such as an air bearing with a clearance of about several μm. Both stages WST and MST can be driven independently in the X-axis direction and the Y-axis direction by a stage drive system 124 (see FIG. 7) including a linear motor or the like.

  Wafer stage WST includes a stage main body 91 and a wafer table WTB mounted on stage main body 91. The wafer table WTB and the stage main body 91 are directed to the base board 12 in directions of six degrees of freedom (X, Y, Z, θx, etc.) by a drive system including a linear motor and a Z / leveling mechanism (including a voice coil motor). It can be driven to θy, θz).

  At the center of the upper surface of wafer table WTB, a wafer holder (not shown) for holding wafer W by vacuum suction or the like is provided. As shown in FIG. 2 (A), a circular opening that is slightly larger than the wafer holder is formed in the center outside the wafer holder (wafer mounting area), and has a rectangular outer shape (contour). (Liquid repellent plate) 28 is provided. The surface of the plate 28 is subjected to a liquid repellent treatment (forms a liquid repellent surface) with respect to the liquid Lq. The plate 28 is fixed to the upper surface of the wafer table WTB so that all or part of the surface thereof is flush with the surface of the wafer W.

  The plate 28 has a first liquid-repellent region (first liquid-repellent plate) 28a having a rectangular outer shape (contour) in which the above-described circular opening is formed in the center, and a rectangular frame shape (annular) disposed around the plate 28. And a second liquid repellent region (second liquid repellent plate) 28b.

  A measurement plate 30 is provided at the + Y side end of the first liquid repellent plate 28a. The measurement plate 30 is provided with a reference mark FM at the center, and a pair of aerial image measurement slit patterns (slit-shaped measurement patterns) SL are provided on both sides of the reference mark FM in the X-axis direction. Corresponding to each aerial image measurement slit pattern SL, there is provided a light transmission system (not shown) for guiding the illumination light IL passing therethrough to the outside of wafer stage WST (a light receiving system provided in measurement stage MST described later). It has been.

On the second liquid repellent plate 28b, a scale used in an encoder system described later is formed. More specifically, Y scales 39Y ₁ and 39Y ₂ are formed in regions on one side and the other side of the second liquid repellent plate 28b in the X-axis direction (left and right direction in FIG. 2A). . The Y scales 39Y ₁ and 39Y ₂ are, for example, reflective type gratings (for example, diffraction gratings) in which the Y axis direction is a periodic direction in which grid lines 38 having the X axis direction as the longitudinal direction are arranged at a predetermined pitch in the Y axis direction. ).

Similarly, a region between one side and the other side of the second liquid repellent plate 28b in the Y-axis direction (upper and lower sides in the drawing in FIG. 2A) is sandwiched between Y scales 39Y ₁ and 39Y ₂ . X scales 39X ₁ and 39X ₂ are formed, respectively. The X scales 39X ₁ and 39X ₂ are, for example, reflection type gratings (for example, diffraction gratings) in which the X-axis direction is a periodic direction in which grid lines 37 having a longitudinal direction in the Y-axis direction are arranged in the X-axis direction at a predetermined pitch. ).

  The pitch of the grid lines 37 and 38 is set to 1 μm, for example. In FIG. 2A and other figures, the pitch of the grating is shown larger than the actual pitch for the convenience of illustration.

  In order to protect the diffraction grating, it is also effective to cover it with a glass plate having a low thermal expansion coefficient having liquid repellency. Here, as the glass plate, a glass plate having the same thickness as the wafer, for example, a thickness of 1 mm can be used, and the wafer table so that the surface of the glass plate is the same height (level) as the wafer surface. Installed on top of WST.

  Further, as shown in FIG. 2A, a reflecting surface 17a and a reflecting surface 17b used in an interferometer system to be described later are formed on the −Y end surface and the −X end surface of the wafer table WTB.

  The measurement stage MST includes a stage main body 92 that is driven in the XY plane by a linear motor (not shown) and the like, and a measurement table MTB mounted on the stage main body 92. As with wafer stage WST, measurement stage MST is also configured to be capable of being driven in directions of six degrees of freedom (X, Y, Z, θx, θy, θz) with respect to base board 12 by a drive system (not shown).

  In FIG. 7, a stage drive system 124 is shown including a drive system for wafer stage WST and a drive system for measurement stage MST.

  Various measurement members are provided on the measurement table MTB (and the stage main body 92). As this measuring member, for example, as shown in FIG. 2B, an illuminance unevenness sensor 94, an aerial image measuring instrument 96, a wavefront aberration measuring instrument 98, an illuminance monitor (not shown), and the like are provided. Further, the stage main body 92 is provided with a pair of light receiving systems (not shown) in an arrangement facing the above pair of light sending systems (not shown). In the present embodiment, each aerial image measurement slit pattern SL of measurement plate 30 on wafer stage WST is measured in a state where wafer stage WST and measurement stage MST are close to each other within a predetermined distance in the Y-axis direction (including a contact state). An aerial image measuring device 45 (see FIG. 7) is constructed in which the transmitted illumination light IL is guided by each light transmission system (not shown) and received by a light receiving element of each light receiving system (not shown) in the measurement stage MST. The

  Further, reflection surfaces 19a and 19b for interferometers are formed on the + Y end surface and the −X end surface of the measurement table MTB.

  A fiducial bar (hereinafter abbreviated as “FD bar”) 46 extends in the X-axis direction on the −Y side end surface of the measurement table MTB, as shown in FIG. Reference gratings (for example, diffraction gratings) 52 having a periodic direction in the Y-axis direction are formed in the vicinity of one end and the other end in the longitudinal direction of the FD bar 46 in a symmetrical arrangement with respect to the center line CL. . A plurality of reference marks M are formed on the upper surface of the FD bar 46. As each reference mark M, a two-dimensional mark having a size detectable by an alignment system described later is used. The surface of the FD bar 46 and the surface of the measurement table MTB are also covered with a liquid repellent film.

In the exposure apparatus 100 of the present embodiment, as shown in FIGS. 4 and 5, a primary alignment system AL1 having a detection center is arranged on the reference axis LV at a position a predetermined distance from the optical axis to the −Y side. Has been. Primary alignment system AL1 is fixed to the lower surface of the main frame (not shown). Secondary alignment systems AL2 ₁ , AL2 ₂ , AL2 ₃ , AL2 _{4 in} which detection centers are arranged almost symmetrically with respect to the reference axis LV are disposed on one side and the other side of the X-axis direction across the primary alignment system AL1. Each is provided. The secondary alignment systems AL2 _{1 to} AL2 ₄ are fixed to the lower surface of the main frame (not shown) via a movable support member, and the X-axis is used using the drive mechanisms 60 _{1 to} 60 ₄ (see FIG. 7). The relative positions of these detection areas can be adjusted with respect to the direction.

In the present embodiment, for example, an image processing type FIA (Field Image Alignment) system is used as each of the alignment systems AL1, AL2 _{1 to} AL2 ₄ . Imaging signals from each of the alignment systems AL1, AL2 _{1 to} AL2 ₄ are supplied to the main controller 20 via a signal processing system (not shown).

As shown in FIG. 3, interferometer system 118 projects an interferometer beam (measurement beam) onto each of reflecting surfaces 17a and 17b, receives the reflected light, and measures the position of wafer stage WST. The interferometer 16, the three X interferometers 126 to 128, the Y interferometer 18 that measures the position of the measurement stage MST, and the X interferometer 130 are provided. More specifically, the Y interferometer 16 reflects at least three length measuring beams parallel to the Y axis including a pair of length measuring beams B4 ₁ and B4 ₂ symmetric with respect to the reference axis LV, and a movable mirror 41 described later. Project to. Further, X interferometer 126, as shown in FIG. 3, the parallel measurement beam into at least three X-axis including symmetrical pair of measurement beams B5 _1, B5 ₂ with respect to reference axis LH reflection surface 17b Project. The X interferometer 127 projects at least two length measuring beams parallel to the Y axis onto the reflecting surface 17b, including the length measuring beam B6 having the reference axis LA as the length measuring axis. Further, the X interferometer 128 projects a measurement beam B7 parallel to the Y axis onto the reflection surface 17b.

  Position information from each interferometer of the interferometer system 118 is supplied to the main controller 20. Based on the measurement results of Y interferometer 16 and X interferometer 126 or 127, main controller 20 adds rotation information in the θx direction (ie, X and Y positions of wafer table WTB (wafer stage WST)). Pitching), rotation information in the θy direction (that is, rolling), and rotation information in the θz direction (that is, yawing) can also be calculated.

  As shown in FIG. 1, a movable mirror 41 having a concave reflecting surface is attached to the side surface on the −Y side of the stage main body 91. As can be seen from FIG. 2A, the movable mirror 41 is designed such that the length in the X-axis direction is longer than the reflecting surface 17a of the wafer table WTB.

  A pair of Z interferometers 43A and 43B that constitute part of the interferometer system 118 (see FIG. 7) are provided facing the movable mirror 41 (see FIGS. 1 and 3). The Z interferometers 43A and 43B project two length measuring beams B1 and B2 through the movable mirror 41, for example, to fixed mirrors 47A and 47B fixed to a frame (not shown) that supports the projection unit PU. And each reflected light is received and the optical path length of length measuring beam B1, B2 is measured. Based on the result, main controller 20 calculates the position of wafer stage WST in the four degrees of freedom (Y, Z, θy, θz) direction.

  In the present embodiment, position information (including rotation information in the θz direction) of wafer stage WST (wafer table WTB) in the XY plane is mainly measured using encoder system 150 described later. Interferometer system 118 is used when wafer stage WST is located outside the measurement area of encoder system 150 (for example, near the unloading position and loading position). Further, it is used as an auxiliary when correcting (calibrating) long-term fluctuations in the measurement results of the encoder system 150 (for example, due to deformation of the scale over time). Of course, interferometer system 118 and encoder system 150 may be used in combination to measure all position information of wafer stage WST (wafer table WTB).

  As shown in FIG. 3, the Y interferometer 18 and the X interferometer 130 of the interferometer system 118 project interferometer beams (measurement beams) onto the reflecting surfaces 19 a and 19 b, and each reflected light is projected. By receiving the light, position information of the measurement stage MST (for example, including at least position information in the X-axis and Y-axis directions and rotation information in the θz direction) is measured, and the measurement result is supplied to the main controller 20. .

  In the exposure apparatus 100 of the present embodiment, a plurality of encoder systems 150 are configured to measure the position (X, Y, θz) in the XY plane of the wafer stage WST independently of the interferometer system 118. A head unit is provided.

As shown in FIG. 4, four head units 62A, 62B, 62C, and 62D are arranged on the + X side, + Y side, -X side of the nozzle unit 32, and -Y side of the primary alignment system AL1, respectively. ing. Head units 62E and 62F are provided on both outer sides in the X-axis direction of the alignment systems AL1, AL2 _{1 to} AL2 ₄ , respectively. These head units 62A to 62D are fixed in a suspended state to a main frame (not shown) that holds the projection unit PU via support members.

As shown in FIG. 5, each of the head units 62A and 62C includes a plurality of (here, five) Y heads 65 _{1 to} 65 ₅ and Y heads 64 ₁ to 64 ₅ . Here, the Y heads 65 _{2 to} 65 ₅ and the Y heads 64 ₁ to 64 ₄ are arranged on the reference axis LH with an interval WD. Y heads 65 ₁ and Y head 64 ₅ are disposed on the -Y side position of a predetermined distance apart nozzle units 32 in the -Y direction from the reference axis LH. The distance in the X-axis direction between the Y heads 65 ₁ and 65 _{2 and} between the Y heads 64 ₄ and 64 ₅ is also set to WD. The Y heads 65 _{1 to} 65 ₅ and the Y heads 64 ₅ to 64 ₁ are disposed symmetrically with respect to the reference axis LV. Hereinafter, Y heads 65 _{1 to} 65 ₅ and Y heads 64 ₁ to 64 ₅ are also referred to as Y head 65 and Y head 64, respectively, as necessary.

The head unit 62A uses a Y scale 39Y ₁ to measure a Y-axis position (Y position) of the wafer stage WST (wafer table WTB) in the Y-axis direction (Y-lens here) Y linear encoder 70A (FIG. 7). To configure). Similarly, the head unit 62C constitutes a multi-lens (here, 5 eyes) Y linear encoder 70C (see FIG. 7) that measures the Y position of the wafer stage WST (wafer table WTB) using the Y scale 39Y ₂ . To do. In the following, the Y linear encoder is abbreviated as “Y encoder” or “encoder” as appropriate.

Here, the interval WD in the X-axis direction of the five Y heads 65 and 64 (more precisely, the projection points on the scale of the measurement beams emitted by the Y heads 65 and 64) provided in the head units 62A and 62C, respectively, is The Y scales 39Y ₁ and 39Y ₂ are set slightly narrower than the width in the X-axis direction (more precisely, the length of the grid lines 38). Accordingly, at least one of the five Y heads 65 and 64 always faces the corresponding Y scales 39Y ₁ and 39Y ₂ (projects a measurement beam).

As shown in FIG. 5, the head unit 62B is arranged on the + Y side of the nozzle unit 32 (projection unit PU), and a plurality of (here, four) X heads 66 arranged on the reference axis LV with a spacing WD. It is equipped with a _{5-66 8.} The head unit 62D is disposed on the −Y side of the primary alignment system AL1 on the opposite side of the head unit 62B via the nozzle unit 32 (projection unit PU), and is disposed on the reference axis LV at intervals WD. (Here, four) X heads 66 _{1 to} 66 ₄ are provided. Hereinafter, the X heads 66 _{5 to} 66 ₈ and the X heads 66 _{1 to} 66 ₄ are also referred to as the X head 66 as necessary.

The head unit 62B uses the X scale 39X ₁ to measure the position (X position) of the wafer stage WST (wafer table WTB) in the X-axis direction (here, four eyes) X linear encoder 70B (FIG. 7). Further, head unit 62D uses the X scale 39X _2, multiview that measures the X-position of wafer stage WST (wafer table WTB) (here 4 eyes) constituting the X linear encoder 70D (refer to FIG. 7) . In the following, the X linear encoder is abbreviated as “X encoder” or “encoder” as appropriate.

Here, the interval WD in the Y-axis direction between adjacent X heads 66 (more precisely, projection points on the scale of the measurement beam emitted by the X head 66) included in the head units 62B and 62D is the X scale 39X ₁ , (more precisely, the length of the grating lines 37) 39X ₂ in the Y-axis direction of the width is set narrower than. Accordingly, at least one of the X heads 66 included in the head units 62B and 62D always faces the corresponding X scales 39X ₁ and 39X ₂ (projects a measurement beam).

The distance between the most + Y side X heads 66 ₄ of the most -Y side of the X heads 66 ₅ and the head unit 62D of the head unit 62B is the movement of the Y-axis direction of wafer stage WST, between the two X heads The width of the wafer table WTB is set to be narrower than the width in the Y-axis direction so that it can be switched (connected).

Head unit 62E, as shown in FIG. 5, a Y heads _67i to 674 ₄ of the plurality of (four in this case). Here, the three Y heads 67 _{1 to} 67 ₃ are arranged on the reference axis LA on the −X side of the secondary alignment system AL 21 ₁ at substantially the same interval as the interval WD. Y head 67 _4, from the reference axis LA in the + Y direction are disposed on the + Y side of secondary alignment system AL2 ₁ a predetermined distance away. The distance in the X-axis direction between the Y heads 67 ₃ and 67 ₄ is also set to WD.

Head unit 62F is equipped with a Y heads 68 ₁ to 68 ₄ of a plurality (four in this case). These Y heads 68 ₁ to 68 _4, with respect to the reference axis LV, is disposed on the Y head 67 _{4-67 1} and symmetrical position. That is, three Y heads 68 _{2-68 4,} the + X side of secondary alignment system AL2 _4, are arranged at substantially the same distance as distance WD on reference axis LA. The Y head 68 ₁ is disposed on the + Y side of the secondary alignment system AL2 ₄ that is a predetermined distance away from the reference axis LA in the + Y direction. The distance between the Y heads 68 ₁ and 68 _{2 in} the X-axis direction is also set to WD. Hereinafter, if necessary, the Y heads _67i to 674 ₄ and Y heads 68 ₁ to 68 _4, each describing both Y heads 67 and Y heads 68.

At the time of alignment measurement, at least one Y head 67 and 68 faces the Y scales 39Y ₂ and 39Y ₁ , respectively. The Y position (and θz rotation) of wafer stage WST is measured by Y heads 67 and 68 (that is, Y encoders 70E and 70F constituted by Y heads 67 and 68).

In the present embodiment, the Y heads 67 ₃ and 68 ₂ adjacent to the secondary alignment systems AL2 ₁ and AL2 ₄ in the X-axis direction are used as a pair of reference grids of the FD bar 46 when measuring the baseline of the secondary alignment system. The Y position of the FD bar 46 is measured at the position of each reference grating 52 by the Y heads 67 ₃ and 68 ₂ that face each other and the pair of reference gratings 52. In the following, encoders composed of Y heads 67 and 68 facing the pair of reference gratings 52 are respectively Y linear encoders (also abbreviated as “Y encoder” or “encoder” where appropriate) 70E ₂ and 70F ₂ (FIG. 7). See). For identification purposes, Y encoders composed of Y heads 67 and 68 facing Y scales 39Y ₂ and 39Y ₁ are referred to as Y encoders 70E ₁ and 70F ₁ .

Measurement values of six linear encoders 70A~70F described above, are supplied to main controller 20, the main controller 20, three or linear encoders of linear encoders 70A~70D 70E _1, 70F _1, 70B and 70D The position of the wafer table WTB in the XY plane is controlled based on the three measured values, and the θz direction of the FD bar 46 (measurement stage MST) is determined based on the measured values of the linear encoders 70E ₂ and 70F _2. Control the rotation of

Further, in the present embodiment, the X head 66 ₀ used for calibrating the X encoders 70B and 70D is provided on the + Y side of the X head 66 _{4 with} a gap WD. As described below, X head 66 _0, together with the X heads 66 ₅ faces X scale 39X _1, is installed in a position facing X scale 39X _2. Here, X head 66 _0, 66 ₅ of the distance in the Y-axis direction is set to be substantially equal to the X scales 39X _1, the 39X ₂ distance in the Y-axis direction.

As shown in FIG. 6, the exposure apparatus 100 of the present embodiment includes a multipoint focal position detection system (90a, 90b) for measuring the surface position of the entire surface of the wafer W placed on the wafer stage WST. A plurality of Z heads (72a to 72d, 74 ₁ to 74 ₅ , 76 _{1 to} 76 ₅ ) constituting the surface position measuring system 180 for measuring the position of the wafer stage WST in the Z-axis direction and the tilt direction are provided. ing. As shown in FIG. 7, the Z head is connected to the main controller 20 via a signal processing / selecting device 170 constituting the surface position measuring system 180. Note that details of the multipoint focal position detection system and the surface position measurement system 180 are disclosed in the pamphlet of International Publication No. 2007/097379, and thus detailed description thereof is omitted. In addition, in FIG. 6 and the like, a plurality of detection points irradiated with the detection beams are not individually illustrated, but as elongated detection areas (beam areas) AF extending in the X-axis direction between the irradiation system 90a and the light receiving system 90b. It is shown.

  FIG. 7 shows the main configuration of the control system of the exposure apparatus 100. This control system is mainly configured of a main control device 20 composed of a microcomputer (or a workstation) for overall control of the entire apparatus. In FIG. 7, various sensors provided on the measurement stage MST such as the illuminance unevenness sensor 94, the aerial image measuring device 96, and the wavefront aberration measuring device 98 described above are collectively shown as a sensor group 99.

  In the present embodiment, main controller 20 uses encoder system 150 (see FIG. 7) to enable effective stroke area of wafer stage WST, that is, in an area where wafer stage WST moves for alignment and exposure operations. The position coordinates in the direction of three degrees of freedom (X, Y, θz) can be measured.

  As each encoder head, for example, an interference type encoder head disclosed in International Publication No. 2007/097379 pamphlet is used. In this type of encoder head, two measurement lights are projected onto a corresponding scale, the respective return lights are combined into one interference light, and the intensity thereof is measured using a photodetector.

In this embodiment, by adopting the arrangement of the encoder head as described above, at least one X head 66 is always provided on the X scale 39X ₁ or 39X _2, and at least one Y head 65 is provided on the Y scale 39Y ₁ . at least one Y head 64 in the Y scales 39Y ₂ are opposed respectively. The encoder head facing the scale has the position of the wafer stage WST (more precisely, the measurement beam) in each measurement direction with reference to the position of the head (more precisely, the position of the projection point of the measurement beam). Measure the position of the scale to be projected. The measurement result is supplied to the main controller 20 as the measurement result of the linear encoders 70A to 70D.

Main controller 20 calculates a position (X, Y, θz) of wafer stage WST in the XY plane based on at least three measurement results of linear encoders 70A to 70D. Here, measured values of the X head 66 and the Y heads 65 and 64 (represented as C _X , C _Y1 , and C _Y2 ) are expressed by the following formulas (X, Y, θz) with respect to the position (X, Y, θz) of the wafer stage WST: 1) to (3).

C _X = (p _X −X) cos θz + (q _X −Y) sin θz (1)
C _Y1 = − (p _Y1 −X) sin θz + (q _Y1 −Y) cos θz (2)
C _Y2 = − (p _Y2 −X) sin θz + (q _Y2 −Y) cos θz (3)
However, (p _X , q _X ), (p _{Y 1} , q _{Y 1} ), (p _{Y 2} , q _{Y 2} ) are respectively the X and Y installation positions (more precisely, X head 66, Y head 65, Y head 64). X, Y position of the projection point of the measurement beam). Therefore, main controller 20 substitutes measurement values C _X , C _Y1 , and C _Y2 of the three heads into simultaneous equations (1) to (3), and solves them to obtain them in the XY plane of wafer stage WST. The position (X, Y, θz) is calculated. According to this calculation result, drive control of wafer stage WST is performed.

Further, main controller 20 controls the rotation of FD bar 46 (measurement stage MST) in the θz direction based on the measurement values of linear encoders 70E ₂ and 70F ₂ . Here, the measured values of the linear encoders 70E ₂ and 70F ₂ (represented as C _Y1 and _CY2 respectively) are expressed by equations (2) and (3) with respect to the (X, Y, θz) position of the FD bar 46. Depends on. Accordingly, the θz position of the FD bar 46 is obtained from the measured values C _Y1 and C _{Y2 as in} the following equation (4).

sin θz = − (C _Y1 −C _Y2 ) / (p _Y1 −p _Y2 ) (4)
However, for the sake of simplicity, q _Y1 = q _Y2 is assumed.

  Main controller 20 calculates the XY position of wafer stage WST from the measured values of at least three encoder heads facing the scale. Here, due to the arrangement of the encoder head employed in the present embodiment, the head facing the scale is sequentially replaced with the adjacent head as the wafer stage WST moves. Therefore, main controller 20 sequentially switches the encoder head that monitors the measurement value to calculate the stage position to the adjacent head according to the movement of wafer stage WST.

For example, assume that wafer stage WST has moved in the + X direction as shown in FIG. In this case, as indicated by arrow e ₁ , Y head 64 for measuring the Y position of wafer stage WST is switched from Y head 64 ₃ to Y head 64 ₄ . Further, as shown in FIG. 8B, it is assumed that wafer stage WST has moved in the + Y direction. In this case, as indicated by arrow _{e 2,} X head 66 that measures the X-position of wafer stage WST, from the X heads 66 ₅ to X head 66 _6, is switched. Thus, Y head 64 (and 65) is sequentially switched to the adjacent head as wafer stage WST moves in the X-axis direction. Also, the X head 66 is sequentially switched to the adjacent head as the wafer stage WST moves in the Y-axis direction.

  Since the encoder detects the relative displacement, the reference position must be determined in order to calculate the absolute displacement (that is, the position). Therefore, when the head is switched, the measured value of the head used after the switching, that is, the reference position is reset. This process of resetting the measurement values performed at the time of head switching is also called a linkage process.

  As described above, in order to calculate the (X, Y, θz) position of wafer stage WST, measurement values of at least three heads are required. Therefore, main controller 20 determines three heads (referred to as a second head set) including another head from position measurement using three heads (referred to as a first head set) in the head switching process. Switch to the position measurement to be used. At that time, main controller 20 first solves simultaneous equations (1) to (3) using the measurement values of the three encoder heads belonging to the first head set, and (X, Y, θz) of wafer stage WST. ) Calculate the position. Next, using the (X, Y, θz) position calculated here, the position is newly used from the same theoretical formula as the formulas (1) to (3) followed by the measurement value of the head to be newly used. Find the predicted value that the head should show. Then, main controller 20 sets the predicted value as a measured value (initial value) of a head to be newly used.

  With the above connecting process, the head switching process is completed while maintaining the result (X, Y, θz) of the position measurement of wafer stage WST. Thereafter, using the measurement values of the three heads used after switching, the same simultaneous equations as described above are solved to calculate the (X, Y, θz) position of wafer stage WST. Based on the result, wafer stage WST is driven and controlled.

  Next, a method for calibrating the X encoders 70B and 70D performed in the exposure apparatus 100 of the present embodiment will be described. Prior to the description of the calibration method, the reason why calibration is necessary will be described.

In exposure apparatus 100 of the present embodiment, since the movement stroke of wafer stage WST in the Y-axis direction is long, the position of wafer stage WST in the X-axis direction (Y position) depends on the position (Y position) of wafer stage WST in the Y-axis direction (Y position). The encoder used for the measurement of (X position) is properly used. That is, main controller 20 faces X scale 39X ₁ when wafer stage WST is located in the + Y side half of the movement stroke area in the Y-axis direction, ie, below projection unit PU ( The X position of wafer stage WST is measured using head unit 62B (X encoder 70B) having a head that projects a measurement beam. On the other hand, main controller 20 determines X scale 39X when wafer stage WST is positioned at the −Y side half of the movement stroke region in the Y-axis direction, that is, when it is positioned below alignment systems AL1, AL2 _{1 to} AL2 _4. The X position of wafer stage WST is measured using head unit 62D (X encoder 70D) having a head facing ₂ (projecting a measurement beam).

For example, as shown in FIG. 9, the wafer stage WST, the X heads 66 ₅ constituting the X encoder 70B is moved from the position facing X scale 39X ₁ in the -Y direction, X head 66 ₅ X scales 39X off the _1, X head 66 ₄ constituting the X encoder 70D comes to face the X scale 39X _2. At this time, the main controller 20, switching from X encoder 70B to 70D, i.e., switching from X heads 66 ₅ to scan different X scales to X head 66 ₄ is carried out.

X encoders 70B and 70D are both provided for measuring the X position of wafer stage WST. Therefore, even when measurement is performed using any of the X encoders 70B and 70D, the same measurement value must be output when wafer stage WST is at the same X position. That is, not only when switching between the X heads 66 ₅ and 66 ₄ shown in FIG. 9 but also before and after this switching, when the θz rotation of wafer stage WST is zero, X scale 39X ₁ and X scale 39X ₂ to, the measurement values of X head 66 facing each (66 either _{5-66 8)} and (either 66 ₁ -66 ₄₎ X heads 66 it is important to be consistent.

However, it is difficult to manufacture the X scales 39X ₁ and 39X _{2 with} the same grating portion (grating), and the two X scales 39X ₁ and 39X have no mounting error when mounted on the wafer table WTB. ₂ is also difficult to install. Therefore, even if the X positions of all the X heads 66 coincide with each other and the θz rotation of the wafer stage WST is zero, the X scale 39X ₁ and the X scale 39X _{2 have} the same X position. It is considered that the measurement values of the X heads 66 that irradiate the measurement beam do not match. Actually, since the separation distance between the head unit 62B and the head unit 62D is long, it is difficult to maintain a state in which the X positions of all the X heads 66 coincide with each other over a long period of time. Furthermore, since the exposure apparatus 100 of the present embodiment employs the immersion exposure method, the immersion area 14 frequently travels on _one X scale 39X ₁ . Here, if the liquid Lq forming the liquid immersion region 14 is not completely recovered and remains on the scale even a little, it is generated by the thermal stress generated by the temperature difference between the liquid and the scale, or the liquid vaporizes. The X scale 39X ₁ is distorted by the heat of vaporization. For this reason, the distortion of the X scale 39X ₁ is particularly large compared to the X scale 39X ₂ , and is expected to further increase with the use of the apparatus. Therefore, it is difficult to guarantee the coincidence of the measured values of the X heads 66 ₅ and 66 ₄ over a long period of time.

For this reason, in the present embodiment, calibration data for calibrating the X encoders 70B and 70D is created according to the calibration method described below, and at least the X encoders 70B and 70D are used by using the created calibration data. Calibrate one. In the present embodiment, it is assumed that the measurement value of the X encoder 70B using the X scale 39X ₁ where a large distortion is expected is calibrated with reference to the measurement value of the X encoder 70D.

Upon this calibration, the X heads 66 ₀ described above provided for calibration is used. Since the X head 66 ₀ is installed at a distance WD from the adjacent X head 66 ₄ , for example, as shown in FIG. 9, the X heads 66 ₀ and 66 ₄ can simultaneously face the common X scale 39 X _2. . The X heads 66 ₄ and 66 ₅ are installed at positions facing the X scales 39X ₂ and 39X ₁ at the same time and individually so that they can be switched between the _two . Accordingly, as shown in FIG. 9, the X heads 66 _0, 66 ₄ faces X scale 39X _2, X head 66 ₅ may face the X scale 39X _1. (Also, the X head 66 ₀ can face the X scale 39X ₂ and the X heads 66 ₅ and 66 ₆ can face the X scale 39X _1. )

Further, X head 66 _0, as shown in FIG. 9, when the X heads 66 ₅ faces X scale 39X _1, is installed in a position facing X scale 39X _2. Here, X head 66 _0, 66 ₅ of the distance in the Y-axis direction is set to be substantially equal to the X scale 39X _2, the distance of 39X ₁ in the Y-axis direction.

Therefore, main controller 20 creates calibration data for calibrating X encoders 70B and 70D as follows.
a. Main controller 20 moves wafer stage WST to cause X head 66 ₅ (measurement beam) to face the −X end on the upper surface of X scale 39X ₁ as shown in FIG. The X head 66 ₀ (measurement beam) is opposed to the −X end portion of the upper surface of 39X ₂ . At this time, main controller 20 sets wafer stage WST to the reference state. That is, main controller 20 measures the Z position of wafer stage WST and the position (rotation) in the θy direction using Z interferometers 43A and 43B, and uses the Y interferometer 16 in the θx direction of wafer stage WST. By measuring the position (rotation) in the θz direction, the wafer stage WST is positioned at the reference position in the direction of four degrees of freedom (Z, θx, θy, θz).
b. Next, main controller 20 faces X scale 39X ₂ while maintaining the reference state of wafer stage WST and maintaining the Y position of wafer stage WST based on the measurement value of Y interferometer 16. Based on the measurement value of X head 66 ₀ (encoder 70D), wafer stage WST is scanned and driven in the −X direction at a constant speed as indicated by the white arrow in FIGS. As a result, as shown in FIGS. 10 and 11, the measurement beam of the X head 66 ₅ is scanned on the X scale 39X ₁ along the reference line L _X1 parallel to the X axis, and at the same time, the X head 66 A measurement beam of ₀ is scanned on the X scale 39X ₂ along a reference line L _X2 parallel to the X axis. During the scanning of both the measurement beam, that is, constant speed during the movement of wafer stage WST, main controller 20 (for each or the wafer stage WST is constant distance moved) at a predetermined sampling interval, X head 66 ₀ and X measurement values of the head 66 ₅ E ₁ (x _i) and _{E 2 (x i) (i} = 1~N (N is the total number of samplings)) sampled simultaneously. Here, since high control accuracy is required for yawing (rotation in the θz direction), control may be performed based on the measurement values of the Y encoders 70A and 70C instead of the Y interferometer 16.

In the above, assuming that the reflecting surface 17a is an ideal plane, the X position is maintained during the constant speed movement of wafer stage WST. However, when the reflecting surface is not an ideal plane. In other words, the uneven shape of the reflecting surface is measured in advance, and the X position of wafer stage WST is controlled based on the measurement data, so that wafer stage WST is accurately driven in the Y-axis direction.
c. When the movement of wafer stage WST in the X-axis direction and the sampling of data are completed, main controller 20 measures measured values E ₁ (x _i ) of the two X heads 66 ₅ and 66 ₀ obtained at the respective sampling points. , E ₂ (x _i ) difference ΔE is calculated based on the following equation (5).

ΔE _i = ΔE (x _i ) = E ₁ (x _i ) −E ₂ (x _i ) (5)
d. Next, main controller 20 applies an appropriate interpolation formula to the obtained discrete data ΔE _i to create calibration data (calibration function) ΔE (x) as a continuous function.

  Note that the calculation of Expression (5) may be performed at the stage where sampling of all data is completed as described above, or may be performed immediately after acquisition of each sampling data.

Further, main controller 20 moves wafer stage WST in the X-axis direction based on the measurement value of another measurement device, for example, X interferometer 126, instead of X head 66 ₀ (encoder 70D) facing X scale 39X _2. May be moved at a constant speed. Further, the Z and θy positions of wafer stage WST may be measured using surface position measurement system 180.

Further, as described above, instead of sampling the measurement values of the two X heads 66 ₅ and 66 ₀ while the wafer stage WST is moving, the wafer stage WST is moved step by step at a predetermined step distance (in this case, It is not always necessary to move at a constant speed), and the above sampling may be performed at each step position (stop position).

  In the exposure apparatus 100 of this embodiment, the main controller 20 controls the X encoders 70B and 70D according to the above-described procedure, for example, when the exposure apparatus 100 is started, when processing of the wafer at the head of the lot is started, or when the apparatus 100 is idle. Calibration data is created.

In this embodiment, the following series of steps using wafer stage WST and measurement stage MST are performed according to the same procedure as disclosed in the embodiment of the above-mentioned pamphlet of International Publication No. 2007/097379. Processing operations are performed. That is,
a) When the wafer stage WST is at the unloading position UP shown in FIG. 4, when the wafer W is unloaded and moved to the loading position LP shown in FIG. 4, a new wafer W is placed on the wafer table WTB. To be loaded. In the vicinity of the unloading position UP and loading position LP, the position of wafer stage WST with six degrees of freedom is controlled based on the measurement value of interferometer system 118. At this time, the X interferometer 128 is used.

In parallel with the wafer exchange described above, the baseline measurement of the secondary alignment systems AL2 _{1 to} AL2 ₄ is performed. This baseline measurement is performed in a state in which the θz rotation of the FD bar 46 (wafer stage WST) is adjusted based on the measurement values of the encoders 70E ₂ and 70F ₂ described above, similarly to the method disclosed in the international publication pamphlet. The measurement is performed by simultaneously measuring the reference mark M on the FD bar 46 in the field of view of each secondary alignment system using the _four secondary alignment systems AL2 _{1 to} AL2 ₄ .
b) After completion of the baseline measurement of the loading and secondary alignment systems AL2 _{1 to} AL2 ₄ , the baseline of the prime alignment system AL1 in which the wafer stage WST is moved and the reference mark FM of the measurement plate 30 is detected by the primary alignment system AL1. The first half of the check is performed. Around this time, the origin of the encoder system and interferometer system is reset (reset).
c) Alignment measurement for detecting alignment marks in a plurality of sample shot areas on the wafer W using an alignment system while measuring the position of the wafer stage WST in the direction of 6 degrees of freedom using the encoder system and the Z head. In parallel with this, focus mapping is performed using the multipoint AF system (90a, 90b) (measurement of the surface position (Z position) information of the wafer W with reference to the measurement values of the Z heads 72a to 72d). Is done. Here, after the alignment measurement is started and before the focus mapping is started, the wafer stage WST and the measurement stage MST are in a scrum state, and the wafer stage WST for alignment measurement and focus mapping moves in the + Y direction, Liquid immersion area 14 is transferred from measurement stage MST to wafer stage WST. Then, when the measurement plate 30 reaches just below the projection optical system PL, a pair of alignment marks on the reticle R are measured by the slit scan method using the aerial image measuring instrument, in the latter half of the baseline check of the primary alignment system AL1. Processing is performed.
d) Thereafter, alignment measurement and focus mapping are continued.
e) When the alignment measurement and focus mapping are completed, the wafer is obtained by the step-and-scan method based on the position information of each shot area on the wafer obtained as a result of the alignment measurement and the latest alignment system baseline. A plurality of shot areas on W are exposed, and a reticle pattern is transferred. During the exposure operation, focus leveling control of the wafer W is performed based on information obtained by focus mapping. The Z and θy of the wafer being exposed are controlled based on the measured values of the Z heads 74 and 76, while θx is controlled based on the measured values of the Y interferometer 16.

  In the present embodiment, during the above-described series of operations, main controller 20 sets configuration data created in advance, for example, the latest calibration, when driving wafer stage WST based on the measurement value of X encoder 70B or 70D. The data, that is, the calibration function ΔE (x) is used to calibrate the measured value of at least one of the X encoders 70B and 70D, here the X encoder 70B. That is, main controller 20 obtains correction value X according to the following equation (6), and drives and controls wafer stage WST according to the measured value after calibration.

X = X ₀ −ΔE (x) (6)
Here, X ₀ is an actual measurement value of the X position obtained when a measurement beam is projected from one of the X heads 66 _{5 to} 66 ₈ constituting the X encoder 70B to the point x on the X scale 39X ₁ . The x position of the measurement beam projection point is calculated from the (X, Y, θz) position of wafer stage WST.

  Main controller 20 may execute data sampling for creating calibration data in parallel with another operation such as during wafer alignment measurement or during exposure. However, in this case, since only partial sampling data can be obtained at one time, at least a part of the calibration data is updated after all the data is stored or after the data obtained for a certain period is stored. In addition, old data is appropriately deleted, and calibration data is updated using only new data. Thereby, the time required for calibration can be greatly shortened.

As described above in detail, according to this embodiment, X encoders 70B, in order to calibrate the 70D, the X heads 66 ₀ for calibration, between the projection optical system PL (the primary alignment system AL1) of the head unit 62D Is installed. Further, the separation distance between the X head 66 ₀ and the X head 66 ₄ located on the most + Y side among the X heads belonging to the head unit 62D is equal to the separation distance WD of the other adjacent head, and the X head 66 _0. distance between X head 66 ₅ located closest to the -Y side of the X heads belonging to head units 62B and is set to be substantially equal to each of the corresponding X scales 39X _2, the distance of 39X _1. Then, main controller 20 drives wafer stage WST in the X-axis direction according to the procedure described above, compares and measures the X position using X heads 66 ₀ and 66 ₅ , and matches the measurement results. Create calibration data. Even when the X encoders 70B and 70D (X heads 66 _{1 to} 66 ₄ and 66 _{5 to} 66 ₈ ) are switched and used in accordance with the Y position of the wafer stage WST, the wafer is calibrated using the calibration data. The measurement accuracy of the position measurement of the stage WST matches. Therefore, even when the X encoders 70B and 70D (X heads 66 _{1 to} 66 ₄ , 66 _{5 to} 66 ₈ ) are switched and used, it is possible to always maintain the driving accuracy of the same wafer stage WST.

  Further, according to the present embodiment, at the time of exposure, wafer stage WST is driven as described above, and the driving accuracy is maintained. Accordingly, the pattern of the reticle R can be accurately transferred and formed on each shot area on the wafer W by scanning exposure.

In the above embodiment, since the immersion exposure apparatus is adopted as the exposure apparatus 100, it is expected that the distortion of the X scale 39X ₁ is large, that is, the measurement error of the X encoder 70B is larger than that of the X encoder 70D. Thus, the X encoder 70B is calibrated with reference to the X encoder 70D. However, the present invention is not limited to this, and the present invention can be applied to a dry type exposure apparatus that exposes the wafer W without passing through liquid (water). In this case, a large difference is not expected in the measurement accuracy of both X encoders 70B and 70D. In such a case, for example, calibration data for both X encoders 70B and 70D may be created based on the average of the measured values of the two X heads 66 ₅ and 66 ₀ .

Further, in the above embodiment, on the assumption that the distortion of the X scale 39X ₁ is large, the wafer stage WST is moved at a constant speed in the X axis direction based on the measurement value of the encoder 70D (X head 66 ₀ ). However, in the case of a dry type exposure apparatus, wafer stage WST may be moved at a constant speed in the X-axis direction based on the measured values of X heads 66 ₅ and 66 ₀ . Of course, also in this case, for example, based on the measurement value of the X interferometer 126, the wafer stage WST may be moved at a constant speed in the X-axis direction.

In that case, the main controller 20 measures the X positions of the X scales 39X ₁ and 39X ₂ with reference to the projection points of the respective measurement beams using the X heads 66 ₅ and 66 ₀ according to the same procedure as described above. Then, the average AGV _i (E ₁ , E ₂ ) = {E ₁ (x _i ) + E ₂ (x _i )} / 2 of the respective measured values E ₁ (x _i ), E ₂ (x _i ) is obtained, Deviations of the measured values based on it ΔE _1i = E ₁ (x _i ) −AGV _i (E ₁ , E ₂ ), ΔE _2i = E ₂ (x _i ) −AGV _i (E ₁ , E ₂ ) Ask. Then, an appropriate interpolation formula is applied to the discrete data ΔE _1i and ΔE _2i to create calibration data (calibration function) as a continuous function. The calibration functions obtained for both encoders 70B and 70D are denoted as ΔE ₁ (x) and ΔE ₂ (x).

Then, main controller 20 calibrates the measurement results of X encoders 70B and 70D using the created calibration functions ΔE ₁ (x) and ΔE ₂ (x). Here, for example, the measurement value of the X encoder 70B is calibrated using X = X ₀₁ −ΔE ₁ (x), and the measurement value of the X encoder 70D is used using X = X ₀₂ −ΔE ₂ (x). And calibrate.

Here, X ₀₁ is an actual measurement value of the X position obtained when a measurement beam is projected from one of the X heads 66 _{5 to} 66 ₈ constituting the X encoder 70B to the point x on the X scale 39X ₁ . _{Furthermore, X 02} is an actual measurement value of X the position obtained when projecting the x in the measurement beam point on the X scale 39X ₂ from either X heads 66 ₁ to 66 ₄ constituting the X encoder 70D. The x position of the measurement beam projection point is calculated from the (X, Y, θz) position of wafer stage WST.

In the above embodiment, it is assumed that there is no local damage in both the X scales 39X ₁ and 39X ₂ , and as shown in FIG. 10, the x position only at one y position on the X scales 39X ₁ and 39X _2. A plurality of sampling points (measurement points) with different values were provided. However, if there is local damage, a measurement error that depends on the y position of the sampling point occurs. Therefore, a plurality of sampling points having different y positions are provided, and the same measurement as in the above-described calibration method is performed on them. It is preferable to create calibration data as a two-dimensional function of x and y.

In the calibration method of this embodiment, X encoders 70B, in order to calibrate the 70D, an additional head 66 ₀ for calibration, from the most + Y side of the head 66 ₄ belonging to the head unit 62D, + Y direction distance WD Provided in position. Including the additional head 66 ₀ to the head unit 62D, as a component of X encoder 70D, it may be used in stage position measurement. In this case, the Y coordinate section of the stage WST where the X head 66 ₀ and the X scale 39X ₂ face _{each other} substantially coincides with the Y coordinate section of the stage WST where the X head 66 ₅ and the X scale 39X ₁ face each other. In the switching process between the X encoders 70B and 70D, there is also an advantage that sufficient connection accuracy can be secured.

Further, an additional head 66 ₀ for calibration, from the head 66 ₅ of the most -Y side belonging to head units 62B, may be provided at a distance WD in the -Y direction. Here, the distance between the X heads 66 ₀ and 66 ₄ is selected to be approximately equal to the distance between the X scales 39X ₁ and 39X ₂ . It is also possible to calibrate the X encoders 70B and 70D using the X heads 66 ₀ and 66 ₄ according to the same procedure as the calibration method using the X heads 66 ₀ and 66 ₅ described above. Incidentally, including the additional head 66 ₀ to the head unit 62B, as a component of X encoders 70B, may be used in stage position measurement. In this case, similarly to the above, the section of the Y coordinate of the stage WST where the X head 66 ₀ and the X scale 39X ₁ face _each other and the section of the Y coordinate of the stage WST where the X head 66 ₄ and the X scale 39X ₂ face each other. Since they are almost the same, there is also an advantage that sufficient connection accuracy can be ensured in the switching process between the X encoders 70B and 70D.

Further, instead of providing an additional head, the arrangement interval in the Y-axis direction of the X encoders 70B and 70D is narrowed to the Y interval of the X heads 66 ₀ and 66 ₅ in this embodiment, and the X heads 66 ₀ and 66 ₅ Instead, the X encoders 70B and 70D may be calibrated using the X heads 66 ₄ and 66 ₅ . When this X head arrangement is adopted, the Y coordinate section of the stage WST where the X head 66 ₄ and the X scale 39X ₂ face each other, and the stage WST where the X head 66 ₅ and the X scale 39X ₁ face _{each other} , as described above. Therefore, there is an advantage that sufficient connection accuracy can be secured in the switching process between the X encoders 70B and 70D.

  Note that the configuration of each measuring apparatus such as the encoder system described in the above embodiment is merely an example, and the present invention is of course not limited thereto. For example, in the above-described embodiment, an encoder system having a configuration in which a lattice unit (Y scale, X scale) is provided on a wafer table (wafer stage), and an X head and a Y head are arranged outside the wafer stage so as to face the lattice unit. Although the case where it is adopted has been exemplified, the present invention is not limited to this, and as disclosed in, for example, US Patent Application Publication No. 2006/0227309, an encoder head is provided on the wafer stage, and this is opposed to the outside of the wafer stage. You may employ | adopt the encoder system of the structure which arrange | positions a grating | lattice part (For example, a two-dimensional grating | lattice or a two-dimensionally arranged one-dimensional grating | lattice part). In this case, the Z head may also be provided on the wafer stage, and the surface of the lattice portion may be a reflective surface to which the measurement beam of the Z head is irradiated.

  Further, in the above-described embodiment, the present invention forms an immersion space including an optical path of illumination light between the projection optical system and the plate, and the plate is illuminated with illumination light through the liquid in the projection optical system and the immersion space. However, the present invention can also be applied to an exposure apparatus of a non-immersion exposure system.

  In the above embodiment, the case where the present invention is applied to a scanning exposure apparatus such as a step-and-scan method has been described. However, the present invention is not limited to this, and the present invention is applied to a stationary exposure apparatus such as a stepper. May be. Even in the case of a stepper or the like, the same effect can be obtained because the position of the stage on which the object to be exposed is mounted can be measured using the encoder as in the above embodiment. The present invention can also be applied to a step-and-stitch reduction projection exposure apparatus, a proximity exposure apparatus, or a mirror projection aligner that synthesizes a shot area and a shot area. Further, as disclosed in, for example, US Pat. No. 6,590,634, US Pat. No. 5,969,441, US Pat. No. 6,208,407, etc. The present invention can also be applied to a multi-stage type exposure apparatus provided with a stage. Further, as disclosed in, for example, WO 2005/074014 pamphlet, an exposure apparatus including a measurement stage including a measurement member (for example, a reference mark and / or a sensor) is provided separately from the wafer stage. The present invention is applicable.

  In addition, the projection optical system in the exposure apparatus of the above embodiment may be not only a reduction system but also an equal magnification and an enlargement system, and the projection optical system PL may be not only a refraction system but also a reflection system or a catadioptric system. The projected image may be either an inverted image or an erect image. In addition, the illumination area and the exposure area described above are rectangular in shape, but the shape is not limited to this, and may be, for example, an arc, a trapezoid, or a parallelogram.

The light source of the exposure apparatus of the above embodiment is not limited to the ArF excimer laser, but is a KrF excimer laser (output wavelength 248 nm), F ₂ laser (output wavelength 157 nm), Ar ₂ laser (output wavelength 126 nm), Kr ₂ laser ( It is also possible to use a pulse laser light source with an output wavelength of 146 nm, an ultrahigh pressure mercury lamp that emits a bright line such as g-line (wavelength 436 nm), i-line (wavelength 365 nm), and the like. A harmonic generator of a YAG laser or the like can also be used. In addition, as disclosed in, for example, U.S. Pat. No. 7,023,610, a single wavelength laser beam in an infrared region or a visible region oscillated from a DFB semiconductor laser or a fiber laser as vacuum ultraviolet light, For example, a harmonic which is amplified by a fiber amplifier doped with erbium (or both erbium and ytterbium) and wavelength-converted into ultraviolet light using a nonlinear optical crystal may be used.

  In the above embodiment, it is needless to say that the illumination light IL of the exposure apparatus is not limited to light having a wavelength of 100 nm or more, and light having a wavelength of less than 100 nm may be used. For example, in recent years, in order to expose a pattern of 70 nm or less, EUV (Extreme Ultraviolet) light in a soft X-ray region (for example, a wavelength region of 5 to 15 nm) is generated using an SOR or a plasma laser as a light source, and its exposure wavelength Development of an EUV exposure apparatus using an all-reflection reduction optical system designed under (for example, 13.5 nm) and a reflective mask is underway. In this apparatus, since a configuration in which scanning exposure is performed by synchronously scanning the mask and the wafer using arc illumination is conceivable, the present invention can also be suitably applied to such an apparatus. In addition, the present invention can be applied to an exposure apparatus using a charged particle beam such as an electron beam or an ion beam.

  In the above-described embodiment, a light transmission mask (reticle) in which a predetermined light-shielding pattern (or phase pattern / dimming pattern) is formed on a light-transmitting substrate is used. Instead of this reticle, For example, as disclosed in US Pat. No. 6,778,257, an electronic mask (variable shaping mask, which forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed, as disclosed in US Pat. No. 6,778,257. For example, a non-light emitting image display element (spatial light modulator) including a DMD (Digital Micro-mirror Device) may be used.

  Further, for example, the present invention can be applied to an exposure apparatus (lithography system) that forms line and space patterns on a wafer by forming interference fringes on the wafer.

  Further, as disclosed in, for example, US Pat. No. 6,611,316, two reticle patterns are synthesized on a wafer via a projection optical system, and one scan exposure is performed on one wafer. The present invention can also be applied to an exposure apparatus that performs double exposure of shot areas almost simultaneously.

  The apparatus for forming a pattern on an object is not limited to the above-described exposure apparatus (lithography system), and the present invention can also be applied to an apparatus for forming a pattern on an object by, for example, an inkjet method.

  Note that the object on which the pattern is to be formed in the above embodiment (the object to be exposed to the energy beam) is not limited to the wafer, but other objects such as a glass plate, a ceramic substrate, a film member, or a mask blank. But it ’s okay.

  The use of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing. For example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern onto a square glass plate, an organic EL, a thin film magnetic head, an image sensor ( CCDs, etc.), micromachines, DNA chips and the like can also be widely applied to exposure apparatuses. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates or silicon wafers, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern.

  An electronic device such as a semiconductor element includes a step of designing a function / performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and the exposure apparatus (pattern forming apparatus) of the above-described embodiment. ), A lithography step for transferring a reticle (mask) pattern to the wafer, a development step for developing the exposed wafer, an etching step for removing the exposed member other than the portion where the resist remains by etching, and etching. It is manufactured through a resist removal step for removing unnecessary resist, a device assembly step (including a dicing process, a bonding process, and a package process), an inspection step, and the like. In this case, in the lithography step, the exposure method described above is executed using the exposure apparatus of the above embodiment, and a device pattern is formed on the wafer. Therefore, a highly integrated device can be manufactured with high productivity.

  The calibration method of the present invention, and the mobile object driving method and apparatus for driving the mobile object by applying the calibration method are suitable for driving the mobile object. The exposure method and apparatus of the present invention are suitable for forming a pattern on an object by irradiating an energy beam. The pattern forming method and apparatus of the present invention are suitable for forming a pattern on an object. The device manufacturing method of the present invention is suitable for manufacturing an electronic device such as a semiconductor element or a liquid crystal display element.

It is a figure which shows schematically the structure of the exposure apparatus which concerns on one Embodiment. 2A is a plan view showing the wafer stage, and FIG. 2B is a plan view showing the measurement stage. It is a top view which shows arrangement | positioning of the stage apparatus with which the exposure apparatus of FIG. 1 is equipped, and an interferometer. It is a top view which shows arrangement | positioning of the stage apparatus and sensor unit with which the exposure apparatus of FIG. 1 is provided. It is a top view which shows arrangement | positioning of an encoder head (X head, Y head) and an alignment system. It is a top view which shows arrangement | positioning of Z head and a multipoint AF system. It is a block diagram which shows the main structures of the control system of the exposure apparatus which concerns on one Embodiment. FIGS. 8A and 8B are views for explaining wafer table position measurement and switching between heads using an encoder composed of a plurality of heads. It is a figure for demonstrating switching between the X head which belongs to the head unit 62B, and the X head which belongs to the head unit 62D. It is FIG. (1) for demonstrating the method to produce the calibration data for calibrating X encoder 70B, 70D. It is FIG. (2) for demonstrating the method to produce the calibration data for calibrating X encoder 70B, 70D.

Explanation of symbols

20 ... main control unit, 39X _1, 39X ₂ ... X scales 39Y _1, 39Y ₂ ... Y scale, 50 ... stage device, 62a to 62f ... head unit, 64 and 65 ... Y head, 66 ... X heads 67, 68 ... Y head, 70A, 70C ... Y encoder, 70B, 70D ... X encoder, 100 ... exposure apparatus, 118 ... interferometer system, 124 ... stage drive system, 150 ... encoder system, 200 ... measuring system, W ... wafer, WST ... wafer stage, WTB ... wafer table.

Claims (21)

A calibration method for calibrating the accuracy of driving a moving body along a predetermined plane,
The moving body is driven in a first direction parallel to one axis in the predetermined plane, and the first direction provided on one surface substantially parallel to the predetermined plane of the moving body is set as a periodic direction. , the second grating, by a pair of opposed encoder heads respectively, a step of measuring the position of the movable body in the first direction;
Creating calibration data for calibrating measured values of at least one of the pair of encoder heads based on the measurement results of the pair of encoder heads;
A calibration method comprising:   2. The calibration method according to claim 1, wherein, in the creating step, calibration data for calibrating the other measurement value with reference to one measurement value of the pair of encoder heads is created.   The calibration method according to claim 1, wherein, in the creating step, calibration data for calibrating the measurement values of both of the pair of encoder heads based on an average of the measurement values is created. The calibration method according to any one of claims 1 to 3 , wherein the first and second gratings are spaced apart from each other in a second direction parallel to an axis orthogonal to the one axis within the predetermined plane. A moving body driving method for driving a moving body along a predetermined plane,
A plurality of first gratings that can be opposed to first and second gratings each having a periodic direction in a first direction parallel to one axis in the predetermined plane provided on one surface of the movable body substantially parallel to the predetermined plane. 1, measuring the position of the moving body in the first direction using at least one of the first and second head units including the second encoder head;
The step of driving the moving body based on the measurement result of the measuring step and the calibration data created using the calibration method according to any one of claims 1 to 4 ;
A moving body drive method including: The moving body drive method according to claim 5 , further comprising a step of switching an encoder head to be used between the first and second head units according to the position of the moving body. In the switching step, the moving body includes a first moving area of the moving body in which the first encoder head faces the first grating, and a moving body of the moving body in which the second encoder head faces the second grating. The second moving area is used after switching so that the measured value of the position of the moving body is maintained before and after switching while the two moving areas move through the overlapping area. The moving body drive method according to claim 6 , wherein the measurement value of the encoder head is reset. An exposure method for irradiating an energy beam to form a pattern on an object,
An exposure method including a step of driving a moving body that holds the object by using the moving body driving method according to any one of claims 5 to 7 , in order to form the pattern. A pattern forming method for forming a pattern on an object,
To form the pattern, using the movable body drive method according to any one of claims 5-7, a pattern forming method of the mobile includes the step of driving along a predetermined plane holding the object . The object has a sensitive layer;
The pattern forming method according to claim 9 , wherein the pattern is formed by irradiating the sensitive layer with an energy beam. The pattern forming method according to claim 10 , wherein the energy beam is irradiated through an optical system and a liquid supplied between the optical system and the object. Forming a pattern on an object using the pattern forming method according to any one of claims 9 to 11 ;
Processing the object on which the pattern is formed;
A device manufacturing method including: A moving body driving apparatus that drives a moving body along a predetermined plane,
A plurality of first gratings that can be opposed to first and second gratings each having a periodic direction in a first direction parallel to one axis in the predetermined plane provided on one surface of the movable body substantially parallel to the predetermined plane. A first and second head unit that includes a second encoder head and measures the position of the moving body in the first direction;
A storage device for storing calibration data created using the calibration method according to any one of claims 1 to 4 ;
A driving device for driving the moving body based on a measurement result of the position of the moving body obtained using at least one of the first and second head units and the calibration data;
A moving body drive apparatus comprising: 14. The moving body drive device according to claim 13 , wherein the first and second gratings are spaced apart from each other in a second direction parallel to an axis orthogonal to the one axis within the predetermined plane. Among the plurality of first and second encoder heads, at least a pair of the first and second encoder heads in the second direction has a separation distance in the second direction of the first and second gratings, and The moving body drive apparatus according to claim 13 or 14 , which is substantially equal. The mobile body drive device according to any one of claims 13 to 15 , further comprising a switching device that switches an encoder head to be used between the first and second head units according to the position of the mobile body. . In the switching device, the moving body includes a first moving area of the moving body in which the first encoder head faces the first grating, and a moving body of the moving body in which the second encoder head faces the second grating. The second moving area is used after switching so that the measured value of the position of the moving body is maintained before and after switching while the two moving areas move through the overlapping area. The movable body drive device according to claim 16 , wherein the measurement value of the encoder head is reset. An exposure apparatus that irradiates an energy beam to form a pattern on an object,
To form the pattern, to drive along a movable body that holds the object in a predetermined plane, an exposure apparatus including a movable body drive system according to any one of claims 13-17. A pattern forming apparatus for forming a pattern on an object,
A movable body that holds and moves the object;
A pattern generator for forming a pattern on the object;
The mobile body drive device according to any one of claims 13 to 17 , wherein the mobile body is driven along a predetermined plane;
A pattern forming apparatus comprising: The object has a sensitive layer;
The pattern forming apparatus according to claim 19 , wherein the pattern generating apparatus forms the pattern by irradiating the sensitive layer with an energy beam. The pattern generation apparatus includes an optical system,
21. The pattern forming apparatus according to claim 20 , further comprising a liquid supply device that supplies a liquid between the optical system and the object.

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