JPWO2005124832A1 - Exposure equipment - Google Patents

Abstract

A plurality of measurement points of the off-axis surface position measurement apparatus are arranged in the frame-shaped region MA so as to surround the exposure region IA in a single layer. In this way, the area on the wafer W that reaches the exposure area IA passes through the frame-shaped area MA, and when the area is exposed, a surface shape map of the area is created. It is in a state. Therefore, by adjusting the surface position of the wafer W based on the surface shape map, high-precision exposure can be performed without arranging measurement points for measuring the surface position of the wafer W in the exposure region.

Description

  The present invention relates to an exposure apparatus, and more particularly to an exposure apparatus that irradiates exposure light onto the surface of an object via a projection optical system.

  Conventionally, in a lithography process for manufacturing an electronic device such as a semiconductor element (integrated circuit) or a liquid crystal display element, an image of a pattern of a mask or a reticle (hereinafter collectively referred to as “reticle”) is transmitted via a projection optical system. 2. Description of the Related Art A projection exposure apparatus is used that transfers to each shot area on a photosensitive substrate (hereinafter referred to as “substrate” or “wafer”) such as a wafer or glass plate coated with a resist (photosensitive agent). As this type of projection exposure apparatus, a step-and-repeat type reduction projection exposure apparatus (so-called stepper) has been conventionally used, but recently, a step-and-repeat that performs exposure while synchronously scanning a reticle and a wafer. A scanning projection exposure apparatus (so-called scanning stepper) is also attracting attention.

  When performing exposure using this type of exposure apparatus, the position of the substrate with respect to the optical axis direction of the projection optical system is set to a focus position detection system (focus) in order to suppress the occurrence of exposure failure due to defocus as much as possible. A detection system), and based on the detection result, the surface of the substrate corresponding to the exposure area (area irradiated with the exposure light) is adjusted to the best imaging plane of the projection optical system within the range of the depth of focus. Auto focus / leveling control is performed. Usually, as such a focus position detection system, an oblique incidence type multi-point focus position detection system (hereinafter referred to as a “multi-point AF system”) that detects a surface position of an area on a substrate corresponding to an exposure area. (For example, refer to Patent Documents 1 and 2).

  However, in the above projection exposure apparatus, the numerical aperture (NA) of the projection optical system has been increased in order to improve the resolution. As the numerical aperture is increased, the projection optical system and the wafer are increased in number. Therefore, it has become difficult to place the measurement points of the multi-point AF system in the exposure area.

In order to solve such inconveniences, recently, an exposure apparatus including an off-axis type wafer W surface position measuring apparatus that does not arrange measurement points in an exposure area has also been proposed (see, for example, Patent Documents 3 and 4). ). However, since this type of off-axis measuring apparatus cannot measure the actual exposure area, further improvement in the measurement accuracy of the surface position of the wafer W is desired.
JP-A-6-283403 US Pat. No. 5,448,332 JP-A-10-154659 US Pat. No. 5,825,043

  The present invention made under the above circumstances is an exposure apparatus that irradiates the surface of an object with exposure light via a projection optical system, and holds the object and is orthogonal to the optical axis of the projection optical system. A stage movable in a dimension plane; and a plurality of measurement points arranged at least in a part around a predetermined area irradiated with the exposure light via the projection optical system, A first measuring device that measures surface position information of the object with respect to the optical axis of the projection optical system; a calculation device that calculates surface shape information of the object based on a measurement result of the first measuring device; A second measurement device that measures position information of the stage; and a control device that controls the surface position of the object with respect to the predetermined region based on the calculation result of the calculation device and the measurement result of the second measurement device. It is an exposure apparatus.

  According to this, the plurality of measurement points of the first measurement device for measuring the surface position information of the object with respect to the optical axis direction of the projection optical system are around a predetermined region irradiated with the exposure light via the projection optical system. Is arranged at least in part. Therefore, before performing exposure on a certain area on the object, the area always passes through the location where the surface position of the object can be measured by multiple measurement points, and the surface shape information of that area is always calculated. Therefore, based on the surface shape information, the area can be matched with the best imaging plane of the projection optical system within the depth of focus during the exposure. As a result, highly accurate exposure can be realized.

1 is a drawing schematically showing a configuration of an exposure apparatus according to a first embodiment of the present invention. It is a figure which shows arrangement | positioning of the measurement point of the surface position measuring apparatus which concerns on the 1st Embodiment of this invention. It is a figure which expands and shows a part of measurement point area | region. It is a figure which shows the relationship between the position of wafer stage WST, and arrangement | positioning of the measurement point of a surface position measuring apparatus. 3 is a diagram illustrating position coordinates of a point to be measured on a wafer W. FIG. It is a figure which shows the area | region of the wafer which measures by a surface position measuring apparatus. It is a figure which shows an example of the position of the wafer stage at the time of wafer loading. It is a figure which shows an example of the position of the wafer stage in search alignment (or wafer alignment). It is a figure which shows the other example of the position of the wafer stage in search alignment (or wafer alignment). It is a figure (the 1) which shows the mode of measurement in three measurement points. It is FIG. (2) which shows the mode of measurement in three measurement points. It is FIG. (3) which shows the mode of measurement in three measurement points. It is a figure which shows measurement error distribution when the movement acceleration of a wafer stage is large. It is a figure which shows measurement error distribution when the movement acceleration of a wafer stage is small. It is a control block diagram which shows the control system of exposure apparatus. It is a figure which shows arrangement | positioning of the measurement point of the surface position measuring apparatus which concerns on the 2nd actual form of this invention. FIG. 4 is a diagram illustrating a relationship between a measurement point region and a region on a wafer W. FIG. 11 is a diagram (No. 1) illustrating a state in which wafer stage WST is moved so that an exposure target area is directed to exposure area IA. FIG. 11 is a diagram (No. 2) illustrating a state in which wafer stage WST is moved so that an exposure target area is directed to exposure area IA. FIG. 11 is a diagram (No. 3) illustrating a state in which wafer stage WST is moved so that an exposure target area is directed to exposure area IA. It is a figure which shows a state when the area | region of exposure object on a wafer is located ranging over a measurement point area | region. It is a figure which shows the plane formed by the surface position measured by area | region MA1-MA3. It is a figure which shows the measured value of the surface position measured by area | region MA2. It is a figure which shows the difference between the plane formed by the surface position measured by area | region MA1-MA3, and the measured value of the surface position measured by area | region MA2. It is a figure which shows a state when the area | region of exposure object on a wafer is located in an exposure area | region. It is a figure which shows the plane formed by the surface position measured by area | region MA1. It is a figure which shows Z position in the center of the exposure area | region of the plane formed by the surface position measured by area | region MA1. It is a figure which shows the estimated surface position in the center of exposure area | region IA. It is a figure which shows the measurement result of the surface shape in points other than the center of exposure area | region IA. It is a figure which shows the estimated surface position in exposure in points other than the center of exposure area IA. It is FIG. (1) which shows the other example of arrangement | positioning of the measurement point of the surface position measuring apparatus in the 2nd Embodiment of this invention. It is a figure which shows the example of arrangement | positioning of the measurement point applied to the exposure apparatus of a step and repeat system. It is FIG. (2) which shows the other example of arrangement | positioning of the measurement point of the surface position measuring apparatus in the 2nd Embodiment of this invention. It is a figure which shows the mode of measurement in the one part measurement point of a surface position measuring apparatus. It is a figure which shows the mode of a measurement in the one part measurement point when a wafer stage moves only the predetermined space | interval from the position shown by FIG. 21 (A). It is a figure which shows typically the connection of a measurement result. It is a figure which shows an example of the surface shape map produced. It is a figure which shows the other example of arrangement | positioning of the measurement point of a surface position measuring apparatus. It is a figure which shows a state when the area | region where the surface shape was measured arrived at the exposure area | region. It is a figure which shows typically the measurement result in the state shown by FIG. It is a figure which shows typically the measurement result in the state shown by FIG. It is a figure which shows the other example of arrangement | positioning of the measurement point of a surface position measuring apparatus. It is a figure which shows typically the connection of the measurement result of a surface position measuring apparatus. It is a figure which shows the other example of arrangement | positioning (single) of the measurement point of a surface position measuring device. It is a figure which shows the example of arrangement | positioning in which the measurement point area | region partially protrudes. It is a figure which shows a state when the area | region where the surface position was measured moved to the exposure area | region. It is a figure (the 1) which shows the example of arrangement | positioning of a measurement point. It is a figure (the 2) which shows the example of arrangement | positioning of a measurement point. It is FIG. (3) which shows the example of arrangement | positioning of a measurement point. It is FIG. (4) which shows the example of arrangement | positioning of a measurement point. It is the example of arrangement when the measurement point area is arranged in the exposure area (part 1). It is the example of arrangement when the measurement point area is arranged in the exposure area (part 2).

<< First Embodiment >>
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 schematically shows the overall configuration of an exposure apparatus 100 according to the first embodiment of the present invention. The exposure apparatus 100 is a step-and-scan projection exposure apparatus (also called a scanning stepper (scanner)).

  The exposure apparatus 100 includes a light source and an illumination optical system, and includes an illumination system 10 that illuminates a reticle R with illumination light (exposure light) IL as an energy beam, a reticle stage RST that holds the reticle R, and a reticle R. A projection unit PU that projects the illumination light IL onto the wafer W, a wafer stage WST on which the wafer W is placed, and a control system thereof.

  The illumination system 10 includes, for example, an illuminance uniformizing optical system including a light source, an optical integrator, and a beam splitter as disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-313250 (corresponding US Patent Application Publication No. 2003/0025890) The slit-shaped illumination area on the reticle R defined by the relay lens, the variable ND filter, and the reticle blind is illuminated with substantially uniform illuminance by the illumination light IL. Here, as the illumination light IL, for example, ArF excimer laser light (wavelength 193 nm) is used. As the optical integrator, a fly-eye lens, a rod integrator (an internal reflection type integrator), a diffractive optical element, or the like can be used. The illumination system 10 may be configured similarly to an illumination system as disclosed in, for example, JP-A-6-349701 and US Pat. No. 5,534,970 corresponding thereto. To the extent permitted by national legislation in the designated country (or selected selected country) designated in this international application, the disclosure in this specification shall be incorporated with the disclosure of each of the above publications and the corresponding published US patent application or US patent. Part.

  The reticle stage RST is levitated and supported on a reticle base (not shown) by an air bearing (not shown) provided on the bottom surface of the reticle stage RST via a clearance of about several μm, for example. On reticle stage RST, reticle R is fixed by, for example, vacuum suction (or electrostatic suction). Here, the reticle stage RST is two-dimensionally within an XY plane perpendicular to the optical axis AX of the projection optical system PL described later by a reticle stage drive unit RSC (not shown in FIG. 1, see FIG. 9) including a linear motor or the like. (In the X-axis direction, the Y-axis direction, and the rotation direction (θz direction) around the Z-axis orthogonal to the XY plane) and a predetermined scanning direction (here, It is possible to drive at a scanning speed designated in the Y-axis direction which is the direction perpendicular to the paper surface in FIG.

  The end surface of the reticle stage RST is mirror-finished, and the position of the reticle stage RST in the stage moving surface is a reticle laser interferometer that irradiates a length measuring beam to the end surface (hereinafter referred to as “reticle interferometer”). 16 is always detected with a resolution of about 0.5 to 1 nm, for example, with a fixed mirror (not shown) fixed to the side surface of the lens barrel 40 constituting the projection unit PU. Actually, an end surface orthogonal to the Y-axis direction and an end surface orthogonal to the X-axis direction are provided on the reticle stage RST, and a corresponding fixed mirror for measuring the position in the X-axis direction and the position in the Y-axis direction are correspondingly provided. A fixed mirror for measurement is provided, and a laser interferometer in the X-axis direction and the Y-axis direction is shown integrated as a reticle interferometer 16 in FIG.

  The interferometers on each axis of the reticle interferometer 16 are a reticle Y interferometer and a reticle X interferometer, respectively. One of the reticle Y interferometer and the reticle X interferometer, for example, the reticle Y interferometer is an interferometer having a measuring axis of two axes. Based on the measurement value of the reticle Y interferometer, in addition to the Y position of the reticle stage RST, the θz direction The rotation of can also be measured. For example, a moving mirror may be provided on the reticle stage RST, and the reflection surface may be used instead of the end surface. Further, at least one corner cube type mirror (for example, a retro reflector) is used instead of the end surface extending in the X-axis direction used for detecting the position of the reticle stage RST in the scanning direction (Y-axis direction in the first embodiment). May be.

  The measurement value of reticle interferometer 16 is sent to main controller 20. Main controller 20 drives and controls reticle stage RST via reticle stage drive unit RSC (not shown in FIG. 1, refer to FIG. 9) based on the measurement value of reticle interferometer 16.

  The projection unit PU is composed of a cylindrical lens barrel 40 and a projection optical system PL composed of a plurality of optical elements held by the lens barrel 40.

  As the projection optical system PL, for example, a refractive optical system including a plurality of lenses (lens elements) having a common optical axis AX in the Z-axis direction is used. Among these lens elements, the lens 91 is arranged closest to the image plane side. The projection optical system PL is, for example, a double-sided telecentric optical system and has a predetermined projection magnification (for example, 1/4 times or 1/5 times). For this reason, when the illumination area of the reticle R is illuminated by the illumination light IL from the illumination system 10, the illumination light IL that has passed through the reticle R passes, for example, the reticle R in the illumination area via the projection optical system PL. A reduced image of the circuit pattern (a reduced image of a part of the circuit pattern) is formed on the wafer W whose surface is coated with a resist (photosensitive agent).

  Note that, in the exposure apparatus 100 of the first embodiment, since exposure using a liquid immersion method is performed, the opening on the reticle side increases as the numerical aperture NA substantially increases. For this reason, in a refractive optical system composed only of lenses, it is difficult to satisfy Petzval's condition, and the projection optical system tends to be enlarged. In order to avoid such an increase in the size of the projection optical system, a catadioptric system (catadioptric system) including a mirror and a lens may be used.

  A liquid supply nozzle 51A and a liquid recovery nozzle 51B constituting the liquid supply / discharge system 32 are located in the vicinity of the lens (hereinafter also referred to as a front lens) 91 on the most image plane side (wafer W side) constituting the projection optical system PL. And are provided. The liquid supply nozzle 51A and the liquid recovery nozzle 51B are held, for example, on a surface plate on which the lens barrel 40 is supported, and are arranged so that the tips thereof face a wafer stage WST described later. In FIG. 1, in order to illustrate the liquid supply / discharge system 32, a part of an alignment detection system AS and a surface position measuring device 60 described later is shown in a crushed state.

  One end of the liquid supply nozzle 51A is connected to a supply pipe (not shown) connected to a liquid supply device 31A (not shown in FIG. 1, refer to FIG. 9). One end of the liquid recovery nozzle 51B is connected to the liquid supply nozzle 51A. Is connected to a recovery pipe (not shown) connected to the liquid recovery device 31B (not shown in FIG. 1, see FIG. 9).

  The liquid supply device 31A includes a liquid tank, a pressure pump, a temperature control device, a valve for controlling supply / stop of the liquid to the supply pipe, and the like. As this valve, for example, it is desirable to use a flow rate control valve so that not only the supply / stop of the liquid but also the flow rate can be adjusted. The temperature control device adjusts the temperature of the liquid in the liquid tank to be approximately the same as the temperature in a chamber (not shown) in which the exposure apparatus 100 is housed.

  The liquid recovery apparatus 31B includes a liquid tank, a suction pump, and a valve for controlling recovery / stop of the liquid via a recovery pipe. As this valve, it is desirable to use a flow rate control valve corresponding to the valve on the liquid supply device 31A side described above.

  Here, as the liquid, ultrapure water (hereinafter simply referred to as “water” unless otherwise required) through which ArF excimer laser light (light having a wavelength of 193 nm) passes is used. Ultrapure water has the advantage that it can be easily obtained in large quantities at a semiconductor manufacturing plant or the like and has no adverse effect on the photoresist, optical lens, etc. on the wafer. In addition, since the ultrapure water has no adverse effect on the environment and the content of impurities is extremely small, it can be expected to clean the surface of the wafer W and the surface of the tip 91.

  The refractive index n of water is approximately 1.44. In this water, the wavelength of the illumination light IL is shortened to 193 nm × 1 / n = about 134 nm.

  Each of the liquid supply device 31A and the liquid recovery device 31B includes a controller, and each controller is controlled by the main controller 20 (see FIG. 9). In response to an instruction from the main controller 20, the controller of the liquid supply device 31A opens a valve connected to the supply pipe at a predetermined opening degree, and water between the leading ball 91 and the wafer W via the liquid supply nozzle 51A. Supply. At this time, the controller of the liquid recovery apparatus 31B opens a valve connected to the recovery pipe at a predetermined opening degree in response to an instruction from the main control apparatus 20, and moves the front ball 91 and the wafer W through the liquid recovery nozzle 51B. Water is recovered in the liquid recovery device 31B (liquid tank) from between the two. At this time, the main controller 20 always makes the amount of water supplied from the liquid supply nozzle 51 </ b> A between the front lens 91 and the wafer W equal to the amount of water recovered through the liquid recovery nozzle 51 </ b> B. Thus, a command is given to the controller of the liquid supply device 31A and the controller of the liquid recovery device 31B. Therefore, a constant amount of water Lq (see FIG. 1) is always held between the front ball 91 and the wafer W. In this case, the water Lq held between the leading ball 91 and the wafer W is always replaced.

  As apparent from the above description, the liquid supply / discharge system 32 of the first embodiment includes the liquid supply device 31A, the liquid recovery device 31B, the supply tube, the recovery tube, the liquid supply nozzle 51A, the liquid recovery nozzle 51B, and the like. It is the liquid supply / drainage system of the local immersion comprised including. In the above description, in order to simplify the description, one liquid supply nozzle and one liquid recovery nozzle are provided. However, the present invention is not limited to this, for example, International Publication No. 99/49504. It is good also as employ | adopting the structure which has many nozzles so that it may be disclosed by number pamphlet. In short, as long as the liquid can be supplied between the optical member (tip lens) 91 of the projection optical system PL arranged closest to the image plane and the wafer W, any configuration is possible. good.

  Note that the distance between the front lens 91 and the wafer W, that is, the working distance is about 1 mm, for example, and is defined very narrowly.

  As shown in FIG. 1, the wafer stage WST is supported in a non-contact manner on a top surface of a stage base BS disposed horizontally below the projection unit PU through a plurality of air bearings provided on the bottom surface thereof. Has been. On wafer stage WST, wafer W is fixed by vacuum chucking (or electrostatic chucking) via wafer holder 70. The surface (upper surface) on the + Z side of the stage base BS is processed so as to have a very high flatness, and this surface serves as a guide surface that is a movement reference surface of the wafer stage WST.

  Wafer stage WST includes an XY stage WS1 that is driven in an XY two-dimensional plane by a drive system such as a linear motor or a planar motor, and a Z / leveling stage WS2 that holds the wafer. The Z-leveling stage WS2 is provided on three actuators 41A to 41C arranged so as not to be aligned on the same line on the XY stage WS1, and the Z-axis direction of the three actuators 41A to 41C is provided. The stage is capable of adjusting the Z position and the inclination with respect to the XY plane by cooperative operation. In FIG. 9, a drive system configured to drive the XY stage WS1 in the XY two-dimensional plane and actuators 41A to 41C is shown integrated as a wafer stage drive unit WSC. That is, the wafer stage WST is driven in the XY plane (including θz) along the guide surface by the wafer stage driving unit WSC below the projection optical system PL in FIG. 1, and the Z-axis direction, θx direction (X It is finely driven in directions of three degrees of freedom: a rotation direction around the axis) and a θy direction (a rotation direction around the Y axis).

  The wafer holder 70 includes a plate-shaped main body and an auxiliary plate (not shown) that is fixed to the upper surface of the main body and has a circular opening having a diameter of about 0.1 to 1 mm larger than the diameter of the wafer W at the center. I have. A large number of pins are arranged in a region inside the circular opening of the auxiliary plate, and the wafer W is vacuum-sucked while being supported by the large number of pins. In this case, when the wafer W is vacuum-sucked, the surface of the wafer W and the surface of the auxiliary plate are set to have almost the same height.

  In addition, a rectangular opening is formed in a part of the auxiliary plate, and a reference mark plate (not shown) is fitted in the opening. The surface of the reference mark plate is flush with the auxiliary plate. On the surface of the reference mark plate, there are at least a pair of reticle alignment first reference marks and an off-axis alignment system (alignment detection system AS described later) having a known positional relationship with respect to the first reference marks. A second reference mark for baseline measurement is formed.

  Position information regarding the XY plane of the wafer stage WST is, for example, 0 by a wafer laser interferometer (hereinafter referred to as “wafer interferometer”) 18XY that irradiates a length measuring beam to the movable mirror 17XY fixed to the Z-leveling stage WS2. It is always detected with a resolution of about 5 to 1 nm. For example, the wafer interferometer 18XY is fixed in a suspended state to a surface plate (not shown) on which the lens barrel 40 is supported, and is fixed to a side surface of the lens barrel 40 constituting the projection unit PU (not shown). The position information of the reflecting surface of the movable mirror 17XY with reference to the reflecting surface is measured as position information in the XY plane of the wafer stage WST.

  Actually, on the wafer stage WST, as shown in FIG. 3, the Y movable mirror 17Y having a reflecting surface orthogonal to the Y-axis direction that is the scanning direction and the reflection orthogonal to the X-axis direction that is the non-scanning direction. An X moving mirror 17X having a surface is provided, and a laser interferometer for measuring an X-axis direction position and a Y-axis direction position is respectively provided correspondingly. In FIG. 1, these are typically shown as a movable mirror 17XY and a wafer interferometer 18XY. For example, the end surface of wafer stage WST may be mirror-finished to form a reflecting surface (corresponding to the reflecting surface of movable mirror 17XY). Of the wafer interferometers 18XY, a laser interferometer for measuring the position in the X-axis direction and a laser interferometer for measuring the position in the Y-axis direction are both multi-axis interferometers having a plurality of measurement axes, and the wafer stage WST In addition to the X and Y positions, rotation (yawing amount (rotation in the θz direction), pitching amount (rotation in the θx direction), and rolling amount (rotation in the θy direction)) can also be measured.

  Position information regarding the Z-axis direction of the Z / leveling stage WS2 constituting the wafer stage WST is always detected by a wafer laser interferometer (hereinafter referred to as “wafer interferometer”) 18Z with a resolution of, for example, about 0.5 to 1 nm. ing. Reflecting mirrors 66A and 66B extend in the Y-axis direction at the −X side end of the XY stage WS1 so that the reflecting surfaces thereof face each other at a predetermined angle. When the wafer interferometer 18Z irradiates two measurement beams parallel to the X-axis direction toward the reflection mirror 66A, the reflection mirror 66A reflects the two measurement beams toward the reflection mirror 66B and reflects them. The mirror 66B reflects the laser beam reflected by the reflection mirror 66A to the + Z side. One of the two length measuring beams reflected by the reflecting mirror 66B reaches, for example, a reference mirror 29Z extending horizontally in the X-axis direction on a surface plate that supports the barrel 40, and the other beam is , Z is set to reach the reflection mirror 67 provided on the bottom surface of the leveling stage WS2. The length measurement beam reflected by the reference mirror 29Z and the reflection mirror 67 travels back in the optical path (that is, through the reflection mirrors 66B and 66A) and returns to the wafer interferometer 18Z. Therefore, in the wafer interferometer 18Z, if the length measurement beam reflected by the reference mirror 29Z is used as reference light and the length measurement beam reflected by the reflection mirror 67 is used as measurement light, the displacement of the Z-leveling stage WS2 in the Z-axis direction can be reduced. It becomes possible to detect.

  In the first embodiment, reference is made so that the wafer interferometer 18Z can always monitor the Z position of the wafer stage WST even while moving between the position below the projection optical system PL and the load position of the wafer W. The length of the mirror 29Z in the X-axis direction is defined. Thus, regardless of the XY position of the Z / leveling stage WS2, the Z position of the Z / leveling stage WS2 of the wafer stage WST can always be detected by the wafer interferometer 18Z.

  Position information (or speed information) of wafer stage WST measured by wafer interferometers 18XY and 18Z is sent to main controller 20. Based on the position information (or speed information) of wafer stage WST, main controller 20 has six degrees of freedom including the XY plane and Z position of wafer stage WST via wafer stage drive unit WSC (see FIG. 9). Control the position of the. In particular, the position control of wafer stage WST in the Z, θx, and θy directions is realized by main controller 20 cooperatively operating actuators 41A, 41B, and 41C that constitute wafer stage drive unit WSC.

  On the −Y side of the projection unit PU, an off-axis alignment detection system AS is installed so as to be supported by a surface plate (not shown) that supports the lens barrel 40. As this alignment detection system AS, for example, the target mark is irradiated with a broadband detection light beam that does not sensitize the resist on the wafer W, and the image of the target mark formed on the light receiving surface by the reflected light from the target mark is not detected. An image processing type FIA (Field Image Alignment) type alignment sensor that captures an image of an index shown in the drawing using an image sensor (CCD) or the like and outputs an image pickup signal thereof is used. The imaging result of the alignment detection system AS is sent to the main controller 20.

≪Surface position measuring device≫
In the first embodiment, the surface position measuring device 60 is provided so as to surround the projection optical system PL. The surface position measuring device 60 may be configured to surround the liquid supply nozzle 51A and the liquid recovery nozzle 51B without surrounding the projection optical system PL. This surface position measuring device 60 is a surface of the wafer W with respect to the direction of the optical axis AX (Z-axis direction) of the projection optical system PL when the wafer W on the wafer stage WST is positioned below the projection optical system PL. It has a plurality of measurement points that can measure the position. FIG. 2A shows an arrangement diagram of the plurality of measurement points. In FIG. 2A, an X′Y ′ coordinate system parallel to the XY coordinate system is set, and the origin of the X′Y ′ coordinate system is set to the position of the optical axis AX of the projection optical system PL. .

  In FIG. 2A, the portion corresponding to the front lens 91 of the projection optical system PL, that is, the field of view PLA of the projection optical system PL is indicated by a one-dot chain line. In the field of view PLA, an exposure area IA in which a partial projection image of a circuit pattern on the reticle R is formed around the origin of the X′Y ′ coordinate system, that is, the optical axis AX of the projection optical system PL is shown. . Since the exposure apparatus 100 is a step-and-scan exposure apparatus, the width of the exposure area IA in the Y-axis direction, which is the scanning direction, is short. This exposure area IA is defined by a reticle blind (movable reticle blind) constituting the illumination system 10.

  Since exposure apparatus 100 is a local liquid immersion type exposure apparatus, exposure area IA is entirely covered with water Lq during exposure. In FIG. 2A, the area immersed in the water Lq covers only a partial area of the field of view PLA of the projection optical system PL, but the field of view PLA of the projection optical system PL is entirely covered with the water Lq. You may make it cover.

Measurement point of the surface position measuring unit 60, around the optical axis AX of the projection optical system PL, on the outside of the field of view PLA of front lens _{91, (+ X 1, +} Y 1), (+ X 1, -Y 1), ( _{-X 1, + Y 1),} (- X 1, on side of the rectangle as vertices -Y ₁₎ (i.e. on the frame-like area), are arranged at a predetermined interval. This frame-like region (measurement point region) is MA, and a predetermined interval is D (see FIG. 2B). Since D is a very short interval, in FIG. 2A, the measurement point area MA composed of the plurality of measurement points is regarded as a continuous area and is indicated by a thick line. In FIG. 2B, a part of the area MA near the position coordinates (+ X ₁ , + Y ₁ ) is shown, and some measurement points included in the part are shown. Here, formed in the measurement points in the area MA are measurement points, respectively, and S _{n (n} = 1~N). That, in the first embodiment, a plurality of measurement points S _n of the surface position measuring device 60 for measuring the surface position of the wafer W, the exposure area IA, are arranged to substantially enclose the XY plane Yes.

The distance D between the measurement points can be set to an arbitrary length, but is preferably set based on the relationship between the depth of focus of the projection optical system PL and the empirical unevenness of the wafer W. Detection principle of the surface position of the wafer W at each measurement point S _n at the surface position measuring unit 60, can be applied to any principle, when employing the detection method using the oblique incident light, for example, Since it can be the same as that disclosed in Japanese Patent Application Laid-Open No. 10-154659, detailed description thereof is omitted. In addition, as long as national laws and regulations of the designated country (or selected selected country) designated in this international application permit, the disclosure in the above-mentioned gazette and the corresponding US patent is incorporated as a part of the description of this specification.

In the first embodiment, using the surface position measuring unit 60 measures the surface position of the point of the wafer W coincides with the plurality of measurement points S _n arranged in the measurement point region MA. FIG. 3 shows a relationship between the measurement point area MA of the surface position measurement device 60 and the XY coordinate system, that is, the wafer stage coordinate system. As shown in FIG. 3, the wafer stage WST (moving mirrors 17X and 17Y constituting the moving mirror 17XY in FIG. 1) is arranged on the X axis arranged at a predetermined distance from the wafer interferometer 18XY in the Y axis direction. Two parallel measuring beams LX1 and LX2 and two measuring beams LY1 and LY2 parallel to the Y axis, which are arranged at a predetermined interval in the X axis direction, are irradiated.

  The measuring beams LX1, LX2 are arranged symmetrically with respect to a straight line passing through the optical axis AX and parallel to the X axis, and the measuring beams LY1, LY2 are arranged in a straight line passing through the optical axis AX and parallel to the Y axis. On the other hand, they are arranged in line symmetry. Therefore, in the first embodiment, the average of the X positions measured by the length measuring beams LX1, LX2 is set as the X position of the wafer stage WST, and the average of the Y positions measured by the length measuring beams LY1, LY2 is the wafer. The Y position of the stage WST can be set.

  That is, in the exposure apparatus 100, the XY position of the wafer stage WST is measured by the wafer interferometer 18XY. In the first embodiment, when the XY position of the wafer stage WST is (X, Y), The position coordinate of the position (point) on the wafer W that coincides with the optical axis AX of the projection optical system PL is (X, Y), and the wafer at that point (X, Y) measured by the surface position measuring device 60 is used. A surface position of W in the Z-axis direction is h (X, Y). That is, h (X, Y) means a measured value of the surface position of a point on the wafer W on the optical axis AX when the XY position of wafer stage WST is (X, Y).

However, the surface position measuring device 60 is an off-axis measuring device, and the surface position of a measuring point having an offset of ± X _{1 in} the X-axis direction and ± Y _{1 in} the Y-axis direction from the optical axis AX of the projection optical system PL. Is to measure. In the first embodiment, it is necessary to measure the surface position of each point on the wafer W in consideration of these offsets.

For example, the wafer W corresponding to the measurement point located at (+ X ₁ , + Y ₁ ) in the X′Y ′ coordinate system among the measurement points respectively arranged at the four corners of the surface position measurement device 60 is the wafer. This is a point located on the optical axis AX when the stage WST moves by −X _{1 in} the X-axis direction and −Y _{1 in the} Y-axis direction. Therefore, at this measurement point, when the XY position of wafer stage WST is (X, Y), the surface of wafer W at the position coordinates (X-X ₁ , Y-Y ₁ ) in the XY coordinate system. The position h (X−X ₁ , Y−Y ₁ ) is measured.

Similarly, when the XY position of wafer stage WST is located at (X, Y), the measurement point located at (+ X ₁ , −Y ₁ ) in the X′Y ′ coordinate system is the position in the XY coordinate system. becomes the coordinates _{(X-X 1, Y +} Y 1) surface position of the wafer W with _{h (X-X 1, Y} + Y 1) is measured, - the (X _1, Y ₁₎ measurement points located, XY It becomes the position coordinate in a coordinate system _{(X + X 1, Y-} Y 1) surface position of the wafer W with _{h (X + X 1, Y} -Y 1) is measured, - located (X _1, -Y ₁₎ At the measurement point, the surface position h (X + X ₁ , Y + Y ₁ ) of the wafer W at the position coordinates (X + X ₁ , Y + Y ₁ ) in the XY coordinate system is measured.

Therefore, as a whole, this surface position measuring apparatus 60 is configured such that (X + X ₁ , Y−Y ₁ ) to (X−X ₁ , Y) when the XY position of wafer stage WST is (X, Y). line segment connecting the _{-Y 1), (X + X} 1, Y-Y 1) a line segment connecting - the _{(X-X 1, Y +} Y 1), (X + X 1, Y-Y 1) ~ (X + X 1, Y-Y line connecting the _1), with _{(X-X 1, Y-} Y 1) ~ (X-X 1, Y + Y 1) interval D surface position predetermined on the wafer W on the four sides corresponding to the line connecting the Measurement is performed at a plurality of arranged measurement points.

FIG. 4 shows a state when the surface area of the wafer W is divided into a lattice pattern at a predetermined interval D. In FIG. 4, in order to illustrate the lattice, the predetermined interval D is enlarged, but this lattice is actually more finely defined with respect to the size of the wafer W. In the first embodiment, the main controller 20 determines the position of the wafer W corresponding to the intersection of the straight lines constituting the lattice (the position coordinates of this point are (x _i , y _i ) (i = 1, 2). ,..., And this point (x _i , y _i )) is a surface shape map of the wafer W using the measurement result of the surface position of the wafer W when it coincides with the measurement point of the surface position measuring device 60. Create

Further, when in this first embodiment, at least one point of the wafer W to the measurement point (x _i, y _i) of the plurality of measurement points S _n of surface position measuring unit 60 are coincident, The surface position of the point (x _i , y _i ) is measured at the measurement point. Each measurement point S _n is the point (x _i, y _i) whether corresponds to may be determined by the XY position of wafer stage WST measured by wafer interferometer 18XY.

The main control unit 20, when the XY position of wafer stage WST measured by the wafer interferometer 18XY is in the range B as shown by hatching in FIG. 5, on the wafer W to coincide with the measurement point S _n A measurement value of the surface position of the point (x _i , y _i ) is acquired as an effective measurement value. This range B is a range within a distance corresponding to the radius r of the wafer W from any one measurement point. If the XY position of wafer stage WST is within this range B, the center of wafer W will be located within this range B. Therefore, as shown by dotted lines in FIG. The surface of the wafer W can be captured at at least one measurement point among the measurement points, and the main controller 20 determines the measurement result at the measurement point of the surface position measurement device 60 as the surface position of the wafer W. It can be acquired as an effective measurement value.

  Note that the point FX shown in FIG. 5 indicates the center (detection center) of the detection field of the alignment detection system AS. As shown in FIG. 5, the detection (detection center) FX of the alignment detection system AS is located within the range B. This means that even when a mark or the like on the wafer W is detected by the alignment detection system AS, at least one measurement point of the plurality of measurement points of the surface position measurement device 60 can measure the surface position of the wafer W. It means that there is.

  The main control unit 20 includes a so-called microcomputer (or workstation) including a CPU (central processing unit) (not shown), a main memory, a storage device, and the like, and executes a predetermined program and the like by this CPU. Thus, as shown in FIG. 9, the entire apparatus is controlled in an integrated manner. In other words, measurement of the surface shape of wafer W, position control of wafer stage WST, and the like are realized by the processing of main controller 20.

  Next, an exposure operation in the exposure apparatus 100 will be described. As a premise, it is assumed that reticle R is already loaded on reticle stage RST, and predetermined preparatory work such as reticle alignment and baseline measurement has been completed. In such an exposure apparatus 100, first, a wafer W to be exposed is loaded on wafer stage WST. This wafer W is not a so-called bare wafer, but is a wafer in which one or more shot regions are already formed. During this loading, as shown in FIG. 6A, the wafer stage WST is -Y from below the projection optical system PL under the control of the main controller 20 via the wafer stage drive unit WSC. The wafer W is moved to the loading position on the side, and the wafer W is loaded by a wafer loader (not shown) at the loading position. In this loading position, the center of the wafer W is assumed to be located outside the range B in FIG. That is, at the time of wafer loading, the wafer W is located outside the measurement range of the surface position measurement device 60 (outside the measurement point area MA).

  Subsequently, main controller 20 moves wafer stage WST holding wafer W by suction downward to alignment detection system AS via wafer stage drive unit WSC, and performs search alignment, wafer alignment, and the like. The search alignment and wafer alignment processes are disclosed in, for example, Japanese Patent Application Laid-Open No. 61-44429 and US Pat. No. 4,780,617 corresponding thereto. In this search alignment and wafer alignment, position information in the XY coordinate system of various alignment marks formed on the wafer W is detected using the alignment detection system AS. For this detection, the wafer stage WST is placed, for example, in FIGS. 6B and 6C, in order to position a plurality of shot regions (sample shots) provided with the marks below the alignment detection system AS. As shown in FIG. In addition, as long as national laws and regulations of the designated country (or selected selected country) designated in this international application permit, the disclosure in the above-mentioned gazette and the corresponding US patent is incorporated as a part of the description of this specification.

In the first embodiment, during the search alignment or wafer alignment, the surface position of the wafer W is measured by the surface position measuring device 60 if possible. For example, when wafer stage WST is located at a position as shown in FIG. 6B, that is, when the center of wafer W is not within range B in FIG. since the wafer W to a position corresponding to S _n does not exist, it does not perform the surface position measurement of the wafer W. When wafer stage WST is located at the position shown in FIG. 6C, that is, when the center of wafer W is within range B in FIG. 5, out of the plurality of measurement points of surface position measurement device 60. Since the wafer W corresponds to at least one measurement point, the surface position of the wafer W is measured at the measurement point.

As described above, the surface position measurement apparatus 60 is configured such that at least one measurement point among the plurality of measurement points coincides with the point (x _i , y _i ) on the wafer W during the search alignment and the wafer alignment. First, the surface position of the wafer W is measured using the measurement point as an effective measurement point. That is, since the wafer stage WST moves in the XY plane from when the wafer W is loaded to when exposure is started, the surface position at the point (x _i , y _i ) on the wafer W is the surface position. Measurement is performed at a plurality of different measurement points of the measurement device 60. For example, FIG. 7A schematically shows three measurement points _Sn , _{Sn + 1} , _{Sn + 2} continuously arranged in the measurement point area MA, and below that, A sectional view of a part of the surface of the wafer W measured by the measurement points S _n , S _{n + 1} and S _{n + 2} is shown. Originally, the surface of the wafer W is under the measurement points S _n , S _{n + 1} , and S _{n + 2} , but for the sake of convenience, description will be given below with reference to FIGS. 7A to 7C. In this case, the surface position measurement apparatus 60 measures the surface position of the point (x _i , y _i ) on the surface of the wafer W that coincides with the measurement points _Sn , _{Sn + 1} , _{Sn + 2.} A point on the surface of the wafer W that coincides with the measurement point _Sn is defined as A (x _A , y _A ). A (x _A , y _A ) is one of the points (x _i , y _i ) on the surface of the wafer W. Next, when wafer stage WST moves to the left side of the paper by distance D, point A on wafer W that was located at measurement point S _{n + 2} comes to be located at measurement point S _{n + 1} . Even at this time, the surface position measuring apparatus 60 measures the surface position of the wafer W at the measurement points _Sn , _{Sn + 1} , _{Sn + 2} . Here, the surface position of the point A is measured at the measurement point _{Sn + 1} . Then, further when the wafer stage WST is moved by a distance D to the left side, point A, which was consistent to the measurement point S _{n + 1} will be positioned on the measurement point S _n. Even at this time, the surface position measuring apparatus 60 measures the surface position of the wafer W at the measurement points _Sn , _{Sn + 1} , _{Sn + 2} . Here, the surface position of the point A is measured at the measurement point S _n.

Thus, when the wafer stage WST is sequentially moved to the left side, the point A is measured at the measurement point _{S n + 2, S n +} 1, S n. That is, as represented by the point A, the surface position of each point (x _i , y _i ) on the surface of the wafer W is moved a plurality of times at different measurement points of the surface position measuring device 60 by the movement of the wafer stage WST. It is measured. Therefore, in the first embodiment, in the main controller 20, at a plurality of measurement points that coincide with the point (x _i , y _i ) on the surface of the wafer W as the wafer stage WST moves. The surface position of the point (x _i , y _i ) is calculated in consideration of the measured value to be measured.

Therefore, in the first embodiment, the main controller 20 applies the measurement value h (x _i , y _i ) of the surface position of the wafer W measured at a predetermined point (x _i , y _i ) A counter t indicating the sampling time t at which the measurement value is obtained is assigned, and the measurement value of the surface position measured at the sampling time t is set to h _t (x _i , y _i ). For example, the measurement value of the surface position at the point A measured at the measurement points S _{n + 2} , S _{n + 1} , and S _n shown in FIGS. 7A to 7C is h ₁ (x _{a, y a), h 2} (x a, y a), h 3 (x a, the y _a).

  In the first embodiment, the surface position of the wafer W is measured by the surface position measuring device 60 regardless of whether the wafer stage WST is stationary or moving. In such a case, the measurement value when wafer stage WST is stationary is different from the measurement value when wafer stage WST is moving, and the tendency of errors included in the measurement value is different. It will fluctuate. In the first embodiment, the surface position of the wafer W is measured in consideration of the reliability of the measurement value under such measurement conditions.

In the first embodiment, the reliability depending on the measurement state of the measurement value h _t (x _i , y _i ) of the wafer W is assumed to be c _t (x _i , y _i ). The possible range of c _t (x _i , y _i ) is 0 <c _t (x _i , y _i ) ≦ 1, and the value when the reliability is highest is 1. In main controller 20, the surface position measurement device 60 responds to the measurement conditions when the surface position h _t (x _i , y _i ) at a certain point (x _i , y _i ) on the surface of the wafer W is measured. To set the value of reliability c _t (x _i , y _i ). As this reliability c _t (x _i , y _i ), a value corresponding to the moving acceleration of wafer stage WST at the time of measurement can be set. For example, when the movement acceleration of wafer stage WST being measured is 0, the reliability of the measurement value can be set to 1, and when the movement acceleration is the maximum, the reliability of the measurement value can be minimized.

8A and 8B show an example of the relationship between the movement acceleration of wafer stage WST and the reliability of the measurement value. 8A and 8B show a probability density function indicating an error distribution occurring in the measurement value. FIG. 8A shows the probability distribution of error ε that occurs in the measured value when the movement acceleration of wafer stage WST is relatively large α _H. FIG. 8B shows a probability distribution of an error ε that occurs in the measured value when the movement acceleration of wafer stage WST is relatively small α _L. As shown in FIGS. 8A and 8B, it can be considered that the error ε generated in the measurement value is generated according to a normal distribution. However, as the moving acceleration of wafer stage WST increases, the error distribution is increased. The standard deviation at is large (σ _H > σ _L ).

Therefore, in the first embodiment, the reliability c _t (x _i , y _i ) is set to a value according to the standard deviation σ of the probability distribution of the error ε according to the movement acceleration of the wafer stage WST, and c _t ( x _i , y _i ) = 1 / σ ² . For example, when the movement acceleration of the wafer stage WST is alpha _H is reliable _{c t (x i, y i} ) , and a 1 / sigma _H ^2, when the moving acceleration of the wafer stage WST is alpha _L The reliability c _t (x _i , y _i ) is 1 / σ _L ² . In the first embodiment, the standard deviation σ of the probability density function of reliability of c _t (x _i , y _i ) approaches 1 as the moving acceleration of wafer stage WST approaches 0. And it is set to be 1 when the movement acceleration is 0.

When the error of the measurement value occurs in accordance with the normal distribution, a value based on the measurement time required for measurement (that is, the time when the measurement point captured the point (x _i , y _i ) on the wafer W) is The reliability c _t (x _i , y _i ) may be used. That is, the longer the measurement time, the more reliable the measurement value, and the shorter the measurement time, the lower the reliability. Therefore, the reliability c _t (x _i , y _i ) is set according to the measurement time. do it.

If a specific relationship not limited to the normal distribution as shown in FIGS. 8A and 8B can be found between the movement acceleration of wafer stage WST and the measurement value error, the relationship is found. Of course, it is also possible to set the reliability c _t (x _i , y _i ) of the measurement value by a method different from the method described above.

With reference to an example of the measurement shown in FIGS. 7A to 7C, the surface position H _t (x _i ) of the point (x _i , y _i ) on the surface of the wafer W in the main controller 20. , Y _i ) will be described. First, as shown in FIG. 7A, when the sampling time t = 1, the surface position of the point A is measured at the measurement point _{Sn + 2} of the surface position measuring device 60, and the measured value is the main control. Acquired by the device 20. This measured value is h ₁ (x _A , y _A ). At this time, since the surface position of the point A has only been measured once, H ₁ (x _A , y _A ) = h ₁ (x _A , y _A ) is set. In the first embodiment, here, the sum C ₁ (x _A , y _A ) of the reliability of the measurement value at the point A is also calculated. C ₁ (x _A , y _A ) is initialized to 0, and c ₁ (x _A , y _A ) is added to C ₁ (x _A , y _A ) (= 0) to obtain C ₁ ( x _A , y _A ) = c ₁ (x _A , y _A ). The calculated H ₁ (x _A , y _A ) and the reliability sum C ₁ (x _A , y _A ) are stored in a storage device (not shown).

Next, as shown in FIG. 7B, at the sampling time t = 2, the surface position measurement device 60 measures the measurement value of the surface position of the point A at the measurement point _{Sn + 1} , and the main control device 20 It is assumed that the measured value is acquired by. Here, the counter value t is incremented by 1 to t = 2, and this measured value is h ₂ (x _A , y _A ).

At this point, the surface position of the point A, which is measured by the measurement point _{S n + 2 h 1 (x} A, y A) and surface position of the point A, which is measured by the measurement point _{S n + 1 h 2 (x} A , Y _A ). The main control device 20 calculates the weighted average of the measured values at the point A so far as the surface position H ₂ (x _A , y _A ) of the point A. As the weight for each measured value, the reliability c _t (x _A , y _A ) (t = 1, 2) of the measured value is used. Therefore, here, {c ₁ (x _A , y _A ) · h ₁ (x _A , y _A ) + c ₂ (x _A , y _A ) · h ₂ (x _A , y _A )} / (c ₁ ( _A value corresponding to x _A , y _A ) + c ₂ (x _A , y _A )) is calculated as the surface position H ₂ (x _A , y _A ).

Note that what is actually stored in the storage device is the sum C _t (x _A , y _A ) of the surface position H ₁ (x _A , y _A ) and the previous reliability c _t (x _A , y _A ). _A ), but as described above, H ₁ (x _A , y _A ) = h ₁ (x _A , y _A ) and C ₁ (x _A , y _A ) = c ₁ (x _A , y _A )), the value of H ₁ (x _A , y _A ) and the value of C ₁ (x _A , y _A ) are read from the storage device and {C ₁ (x _A , y _A ) H ₁ (x _A , y _A ) + c ₂ (x _A , y _A ) h ₂ (x _A , y _A )} / (C ₁ (x _A , y _A ) + c ₂ (x _A , y _A ) ) May be calculated as the surface position H ₂ (x _A , y _A ) of the point A. Further, here, the sum of reliability of measured values C ₂ (x _A , y _A ) = C ₁ (x _A , y _A ) + c ₂ (x _A , y _A ) is also calculated. The calculated H ₂ (x _A , y _A ), C ₂ (x _A , y _A ) is stored as a value of H _t (x _A , y _A ), C _t (x _A , y _A ) (not shown). Store in the device.

Next, as shown in FIG. 7 (C), when the sampling time t = 3, the surface position of the point A at the measurement point S _n of the surface position measuring device 60 is measured, the measurement by the main controller 20 Suppose that a value is obtained. This measured value is assumed to be h ₃ (x _A , y _A ). At this point, the surface position of the point A, which is measured by the measurement point _{S n + 2 h 1 (x} A, y A) and surface position of the point A, which is measured by the measurement point _{S n + 1 h 2 (x} A , and y _a), the surface position h ₃ (x _a of point a which is measured by the measurement point S _n, since y _a) and is _{measured, {c 1 (x a,} y a) · h 1 ( _{x A, y A) + c} 2 (x A, y A) · h 2 (x A, y A) + c 3 (x A, y A) · h 3 (x A, y A)} / (c 1 ( _A value corresponding to x _A , y _A ) + c ₂ (x _A , y _A ) + c ₃ (x _A , y _A )) may be calculated as the surface position H ₃ (x _A , y _A ) of the point A. . However, only the weighted average H ₂ (x _A , y _A ) of each measurement value at t = 1, ₂ and the sum C ₂ (x _A , y _A ) of the reliability of the measurement value are stored in the storage device. Therefore, {C ₂ (x _A , y _A ) · H ₂ (x _A , y _A ) + c ₃ (x _A , y _A ) · h ₃ (x _A , y _A )} / (C ₂ (x _A , Y _A ) + c ₃ (x _A , y _A )) may be calculated as the surface position H ₃ (x _A , y _A ) of the point A. Further, main controller 20 calculates C ₂ (x _A , y _A ) + c ₃ (x _A , y _A ) and calculates the sum C ₃ (x _A , y _A ) of the measured values. The main controller 20 stores the calculated H ₃ (x _A , y _A ) and C ₃ (x _A , y _A ) in a storage device (not shown).

Thus, in the first embodiment, the reliability of the measurement value h _t (x _i , y _i ) at the point (x _i , y _i ) measured at a plurality of different measurement points during the measurement. The weighted average value based on the property c _t (x _i , y _i ) is defined as the surface position H _t (x _i , y _i ) at that point.

The weighted average value H _t (x _i , y _i ) at each point (x _i , y _i ) on the surface of the wafer W can be calculated by sequential calculation. That is, the surface position H _t (x _i , y _i ) at that point is the surface position H _t-1 (x _i , y _i ) calculated up to the previous time and the sum C _t− of the reliability so far. _{From 1} (x _i , y _i ), the surface position h _t (x _i , y _i ) measured this time, and the reliability c _t (x _i , y _i ) at that time, the following equation is obtained. It is done.

また、Ｃ_t（ｘ_i，ｙ_i）は、次式のようになる。

Further, C _t (x _i , y _i ) is expressed by the following equation.

なお、サンプリング時点ｔで、地点（ｘ_i，ｙ_i）が計測点と一致していない場合には、記憶装置に格納されている、その地点での面位置ｈ_t（ｘ_i，ｙ_i）は計測されないので、格納された面位置Ｈ_t-1（ｘ_i，ｙ_i）、信頼性の和Ｃ_t-1（ｘ_i，ｙ_i）が、そのまま、面位置Ｈ_t（ｘ_i，ｙ_i）、信頼性の和Ｃ_t（ｘ_i，ｙ_i）となる。

If the point (x _i , y _i ) does not coincide with the measurement point at the sampling time t, the surface position h _t (x _i , y _i ) at that point stored in the storage device is stored. Is not measured, the stored surface position H _t-1 (x _i , y _i ) and the reliability sum C _t-1 (x _i , y _i ) remain as they are, and the surface position H _t (x _i , y _i ) _i ), the sum of reliability C _t (x _i , y _i ).

  In the first embodiment, the wafer stage is set so that the Z position is always constant and the rolling amount θy and the pitching amount θx are always 0 during the measurement by the surface position measuring device 60. WST control is performed. Therefore, it is assumed that main controller 20 can measure the surface position of wafer W without considering such a Z position and inclination of wafer stage WST. In the above-described example, wafer stage WST is moved by measurement point interval D for each sampling period. Actually, the speed of wafer stage WST varies, and for each sampling period, It is not possible to measure the surface position of an adjacent measurement point. In main controller 20, it is necessary to determine from the measurement values (X, Y) of wafer interferometer 18XY at each sampling period whether each measurement point is captured on wafer W or not.

The method for calculating the surface shape of the wafer W in the first embodiment will be summarized. The main controller 20 has the center of the wafer W located in a range B indicated by the oblique lines in FIG. 5, and the grid intersection (x _i , y _i ) in FIG. When at least one of the measurement points coincides with the measurement point that captures the surface on the wafer W as an effective measurement point, the effective measurement measured by the surface position measurement device 60. The surface position of the wafer W at the point is acquired. Then, main controller 20 determines which point (for example, point A) on the surface of wafer W coincides with the effective measurement point, measurement value (X, Y) of wafer interferometer 18XY, and measurement point. It derived based on the location of S _n. Then, it is determined whether the derived point (x _i , y _i ) is a point where the surface position has already been measured. If the surface position has not yet been measured, The surface position H _t (x _i , y _i ) and the measurement reliability sum C _t (x _i , y _i ) are respectively initialized, and the above equations (1) and (2) are calculated. The surface position H _t (x _i , y _i ) at the point and the measurement reliability sum C _t (x _i , y _i ) are calculated, and if the surface position has already been measured, The surface position H _t-1 (x _i , y _i ) at the point (x _i , y _i ) and the measurement reliability sum C _t-1 (x _i , y _i ) are read from a storage device (not shown). Then, the above formulas (1) and (2) are calculated using the read values, the surface position H _t (x _i , y _i ) at the point (x _i , y _i ), and the sum of the measurement reliability Calculate C _t (x _i , y _i ) And stored in a storage device (not shown).

In the first embodiment, the surface position of the same point on the wafer W is measured a plurality of times. The surface position H _t (x _i , y _i ) calculated so far and The measurement value h _t (x _i , y _i ) of the surface position may be “fooled” to erroneously recognize the Z position measurement result due to some cause, for example, deformation of the detection beam reflected by the circuit pattern on the wafer W, In the case where there is a great difference due to the “water pool” of the water Lq that has not been completely drained, the measurement value h _t (x _i , y _i ) of the current surface position may be rejected. For example, the difference between the measured value h _t (x _i , y _i ) of the surface position measured this time and the weighted average value H _t-1 (x _i , y _i ) at this point until the previous time is greater than or equal to a predetermined threshold value. If so, the measured value h _t (x _i , y _i ) can be rejected.

  In the first embodiment, the surface position of each point on the wafer W is simultaneously measured at a plurality of measurement points arranged at intervals that can be regarded as being substantially continuous. However, a plurality of different measurement points that are simultaneously measured are measured. It is expected that the measured values measured in each will be close to each other. Therefore, the measurement values of a plurality of different measurement points measured simultaneously by performing a predetermined filtering process on the measurement point sequence may be smoothed.

  In the first embodiment, the surface position of the wafer W is measured a plurality of times at a predetermined sampling interval at a certain measurement point. The time-series measurement values measured at this measurement point are subjected to predetermined filtering. You may make it smooth by performing a process.

If the moving speed of wafer stage WST is very high, a certain point (x _i , y _i ) on wafer W moves across a plurality of different measurement points during the sampling period, and these measurement points It may be measured by. In this case, the measurement value of the surface position at the point (x _i , y _i ) at the sampling time t may be, for example, the average value of the measurement values at those measurement points.

In the measurement of the surface position of the wafer W by the surface position measurement device 60, the surface at each measurement point of the surface position measurement device 60 when the wafer stage WST is stationary, such as when a wafer mark is detected by the alignment detection system AS. The position measurement value is preferably the first measurement value. In this way, the time (when the surface position H _t (x _i , y _i ) of each point (x _i , y _i ) of the wafer W converges to a true value that is not affected by the movement of the wafer stage WST ( (Setting time) can be shortened.

≪Calibration between measurement points≫
As described above, the surface position measuring apparatus 60 includes a plurality of measurement points S _{1 to} S _N , and an arbitrary point (x _i) on the surface of the wafer W at the plurality of measurement points S _{1 to} S _N. , Y _i ) are measured. However, the measurement value h (x _i , y _i ) at each measurement point varies depending on the characteristics of the displacement sensor corresponding to each measurement point. Therefore, it is necessary to perform so-called calibration (calibration) for correcting variation (offset) between measurement points of output between the displacement sensors. Hereinafter, this calibration method will be described.

In the first embodiment, as described above, the surface position of each point (x _i , y _i ) on the surface of the wafer W is measured at each measurement point _Sn , and the reliability of the measurement value is weighted. The surface position of each point (x _i , y _i ) on the surface of the wafer W is calculated by averaging. In this calibration method, the surface position obtained from the measurement result of only the measurement point (this measurement point is S _s (s is any one of 1 to N)) at a certain point (x _i , y _i ). Is compared with the surface position obtained from all the measurement results at that point including the measurement value of the surface position at that point measured at another measurement point, and the calibration information at that measurement point is detected .

For example, the main controller 20 measures the measured value h _{s, t} (x _i , y _i ) (for example, the point A) at an arbitrary point (x _i , y _i ) on the surface of the wafer W measured at the measurement point S _s. Measured value h _{s, t} (x _A , y _A )) is obtained, and based on the reliability of the measured value (for example, c _{s, t} (x _i , y _i )), The surface position of the point A measured only at the measurement point S _s is calculated.

なお、Ｃ_s,t-1（ｘ_i，ｙ_i）は、次式で示されるように、ｔ−１回目の計測点Ｓ_sでの計測値の信頼性ｃ_s,t（ｘ_i，ｙ_i）の和Ｃ_s,t（ｘ_i，ｙ_i）である。

Note that C _{s, t-1} (x _i , y _i ) is the reliability c _{s, t} (x _i , y) of the measured value at the t−1th measurement point S _s , as shown in the following equation. _i ) is the sum C _{s, t} (x _i , y _i ).

上述したように、ウエハＷの表面上の地点（ｘ_i，ｙ_i）の面位置Ｈ_t（ｘ_i，ｙ_i）は、ウエハステージＷＳＴの移動により、面位置計測装置６０の複数の異なる計測点での計測値ｈ_t（ｘ_i，ｙ_i）の重み付け平均であるので、この面位置Ｈ_t（ｘ_i，ｙ_i）は、その面位置の計測を行った複数の計測点でのセンサ出力のばらつき（オフセット）が平均化された値となっている。したがって、この較正方法では、この複数の異なる計測点で計測されたウエハＷの表面上の地点の面位置Ｈ_t（ｘ、ｙ）を基準とする、上記式（３）によって検出される、ある計測点Ｓ_sでの所定の地点（ｘ_i，ｙ_i）での面位置Ｈ_s,t（ｘ_i，ｙ_i）のバイアスに基づいて、その計測点Ｓ_sの計測値を補正する補正量を算出する。すなわち、計測点Ｓ_Sの計測値の補正量Ｄ_s,tを、次式を用いて算出する。

As described above, the surface position H _t (x _i , y _i ) of the point (x _i , y _i ) on the surface of the wafer W is measured by a plurality of different measurements by the surface position measuring device 60 by the movement of the wafer stage WST. Since this is a weighted average of the measurement values h _t (x _i , y _i ) at the point, this surface position H _t (x _i , y _i ) is a sensor at a plurality of measurement points at which the surface position was measured. The output variation (offset) is an averaged value. Therefore, in this calibration method, it is detected by the above equation (3) based on the surface position H _t (x, y) of the point on the surface of the wafer W measured at the plurality of different measurement points. predetermined point at the measurement point _{S s (x i, y i} ) surface position H _{s at, t (x i, y i} ) on the basis of the bias correction amount for correcting the measured value of the measurement point S _s Is calculated. That is, the correction amount D _{s, t} of the measurement value at the measurement point S _S is calculated using the following equation.

ここで、Ｄ_s,0＝０としている。すなわち、計測点Ｓ_sの計測値の補正量Ｄ_s,tは、その計測点で計測されたウエハＷの全ての地点における、その計測点での計測値のみで算出された面位置Ｈ_s,t（ｘ_i，ｙ_i）と、他の計測点を含む複数の計測点で計測された地点（ｘ_i，ｙ_i）の面位置Ｈ_t（ｘ_i，ｙ_i）との差分の重み付け平均に応じて決定される。

Here, D _{s, 0} = 0. That is, the correction amount D _{s, t} of the measurement value at the measurement point S _s is the surface position H _s, calculated from only the measurement value at the measurement point at all points of the wafer W measured at the measurement point _{. t} (x _i, y _i) and a plurality of points measured by the measurement point (x _i, y _i) surface position H _t (x _i, y _i) of the difference weighted average of the containing other measurement points It is decided according to.

According to the above equation (5), the sum of the correction amount change amount (D _{s, t} −D _{s, t−1} ) at all measurement points is always 0, and the entire correction amount of the measurement value is There is no shift.

That is, the main control device 20 corrects the measurement value measured at the measurement point S _s of the surface position measurement device 60 with the correction amount D _{s, t} . In this way, the process of measuring the surface position of the wafer W without performing a special operation of measuring variations in sensor output between the measurement points at the plurality of measurement points in the surface position measurement apparatus 60. Can realize calibration. Therefore, it is advantageous in terms of throughput, and the calibration calculation is performed at any time during the measurement of the surface position of the wafer W, so that it is possible to cope with the drift of the sensor output at each measurement point. Further, a reference plane plate having a large area that covers all measurement points of the surface position measurement device 60 and extremely high flatness is provided, and the reference plane plate is provided at all measurement points of the surface position measurement device 60. By measuring the surface position, it is not necessary to perform an operation such as measuring an offset based on the measurement result of the surface position at the measurement point. Therefore, it is not necessary to provide such a reference plane plate on the wafer stage WST. This also has the effect of reducing hardware constraints.

  However, the offset of each measurement point may be obtained in advance by measuring the surface position of such a reference flat plate at a plurality of measurement points.

In the first embodiment, if there is a point on the surface of the wafer W measured by all the measurement points S _{1 to} S _N of the surface position measuring device 60, the surface position of that point only (that is, a predetermined position). The correction amount D _{s, t} is calculated based on the weighted average of the bias at the surface position measured at the measurement point S _S and the surface position measurement value at the entire measurement point). May be requested.

  In the first embodiment, the offset of the sensor output between the measurement points is detected in this way, and the relative relationship between them is obtained. Therefore, the surface position measuring device 60 with respect to the best imaging plane of the projection optical system PL is obtained. When performing calibration, if calibration is performed with some measurement points of the surface position measurement device 60, the best imaging plane of the projection optical system PL and all measurement points of the surface position measurement device 60 are used. This is the same as performing the calibration.

In the first embodiment, the sensor output between the measurement points of the surface position measuring device 60 is calibrated. However, the calibration related to the deformation (distortion) of the wafer stage WST itself accompanying the acceleration / deceleration of the wafer stage WST. May be performed. Specifically, when the movement acceleration of wafer stage WST has a predetermined magnitude, a predetermined point (x _i , y _i ) on the surface of wafer W at predetermined measurement point S _S of surface position measuring device 60 is detected. According to the difference between the measured value of the surface position and the measured value of the surface position of the same point (x _i , y _i ) on the surface of the wafer W at the measurement point when the movement acceleration of wafer stage WST is zero This value may be used as the correction amount of the measured value of the surface position at the moving acceleration.

In the first embodiment, in this way, the output difference between the measurement points of the surface position measurement device 60 is calibrated, and the influence of the drift of the output of each measurement point is canceled, while the surface of the wafer W is corrected. The surface positions H _t (x _i , y _i ) of a plurality of points (x _i , y _i ) are calculated, and the surface shape map of the wafer W (that is, H (x at the measured points (x _i , y _i )) A set of _i , y _i ) is created. When actually performing the scanning exposure, based on the surface shape map, the wafer W is inserted through the wafer stage driving unit WSC so that the surface of the wafer W falls within the focal depth of the best imaging plane of the projection optical system PL. To control wafer stage WST. Specifically, main controller 20 extracts the surface shape at the point on the surface of wafer W corresponding to exposure area IA from the surface shape map from the measured values (X, Y) of wafer interferometer 18XY. Then, a command value corresponding to the extracted surface shape is created, and the command value is used as a feedforward command value for a servo control system that controls the position of wafer stage WST. In this servo control system, feedforward control is performed based on this feedforward command value, and current commands for the actuators 41A to 41C are created. The actuators 41A to 41C each drive the Z / leveling stage WS2 based on the current command, and as a result, the exposure target surface on the wafer W matches the best imaging surface of the projection optical system PL within the depth of focus. To be controlled. During the exposure for performing the surface position control of the wafer W, the Z position measured by the wafer interferometer 18Z is kept constant, and the stage control for setting the pitching amount θx and the rolling amount θy measured by the wafer interferometer 18XY to zero. Shall not be performed.

  During the scan exposure, the water Lq is supplied to the exposure area IA by the liquid supply / discharge unit 32 having the above-described configuration under the control of the main controller 20.

  Needless to say, the surface position of the wafer W can be measured by a plurality of measurement points of the surface position measuring device 60 also when performing this feedforward control. However, during exposure, the Z position of wafer stage WST based on the measurement value of the interferometer and the control for making the tilt constant are not performed, so the Z position of wafer stage WST measured by wafer interferometers 18XY and 18Z, It is necessary to measure the surface position of the wafer W in consideration of the inclination.

  In the first embodiment, during the exposure, the surface position of the wafer W is controlled using only the surface shape map of the wafer W that has been measured in advance. 60, the surface position of the wafer W is measured at a part of the measurement points 60, and the surface position of the wafer W corresponding to the exposure area IA is estimated based on the deviation between the measured value and the surface shape map measured in advance. The surface position of the wafer W may be controlled using the estimated surface position. Also, the measurement value of the surface position measuring device 60 during exposure may be weighted according to the reliability of the measurement value.

As described above in detail, according to the first embodiment, in the surface position measurement apparatus 60, a plurality of measurements for measuring the surface position of the wafer W with respect to the direction of the optical axis AX of the projection optical system PL. The points (S _{1 to} S _N ) are arranged so as to substantially surround the exposure area IA where the pattern image is formed via the projection optical system PL. Therefore, when a pattern is transferred to a certain area on the wafer W, the area is a place where the surface position can be measured by a plurality of measurement points of the surface position measuring device 60 regardless of the traveling direction of the wafer W. Will surely pass. As a result, the main controller 20 can always obtain the surface shape of the area before the exposure of the area, so that the projection optics can be used without directly measuring the surface position of the wafer W in the exposure area IA. The region can be adjusted within the focal depth of the system PL. As a result, highly accurate exposure can be realized.

In the first embodiment, main controller 20 determines a predetermined point (x _i , y on the surface of wafer W at a plurality of different measurement points of surface position measurement device 60 as wafer stage WST moves. _i ) the surface position is measured, and further, it is determined which point on the surface of the wafer W each measurement point captures based on the measurement result (XY position) of the wafer interferometer 18XY when the measurement is performed. Then, the surface position H _t (x _i , y _i ) at the point (x _i , y _i ) in the surface shape map of the wafer W is calculated. In this way, since the surface position of the predetermined point (x _i , y _i ) on the surface of the wafer W can be measured at a plurality of different measurement points, variations in sensor output at each measurement point, etc. Regardless, statistically reasonable surface positions can be calculated. As a result, a highly accurate surface shape map of the wafer W can be created.

In the first embodiment, the main controller 20 determines the weighted average value based on the reliability of the measurement result of the surface position measuring device 60 at a predetermined point on the surface of the wafer W as the surface shape of the wafer W. It is calculated as the surface position H _t (x _i , y _i ) of the wafer W at a predetermined point (x _i , y _i ) in the map. In this way, for example, the surface position can be accurately measured regardless of the measurement conditions when the measurement value is obtained.

  In the first embodiment, the weighted average of the measured values is calculated. Since this calculation formula is a sequential calculation formula for obtaining the current weighted average from the previous weighted average, the past measured values are calculated. Even if not all of them are stored, the above weighted average calculation can be executed. Accordingly, since it is not necessary to store all past measurement values, the storage capacity of the storage device can be reduced.

In the first embodiment, when a predetermined point (x _i , y _i ) on the surface of the wafer W coincides with at least one of the plurality of measurement points of the surface position measurement device 60. First, surface position information of the wafer W at the measurement point is measured. In this way, even if the process of only measuring the surface position of the wafer W is not performed, if the predetermined point of the wafer W happens to be located at the measurement point, the predetermined point (x _i , y _Since the surface position can be measured in _i ), it is advantageous in terms of throughput. In addition, since the surface position of the same point is measured a plurality of times, an appropriate surface position can be calculated from a statistical point of view.

  In particular, the surface position measuring device 60 uses the alignment detection system AS to detect the position information of the wafer mark and the like when detecting the position information of the wafer mark formed on the wafer W, that is, when measuring the search alignment and the wafer alignment. Also at the time of detection, the surface position of the wafer W is measured. In this way, the surface shape of the wafer W can be measured in advance without reducing the throughput, and the surface position of the wafer W can be accurately measured based on the measurement result when the wafer stage WST is stationary. it can. In particular, if measurement of the surface position of wafer W is started while wafer stage WST is stationary during measurement of search alignment and wafer alignment, a highly reliable measurement value is used as an initial value of the measurement value of surface position. Therefore, the convergence of the calculated surface position can be improved.

  In the first embodiment, when the direct relationship between the acceleration of wafer stage WST and the measurement error of surface position measurement device 60 is known, each measurement of surface position measurement device 60 is performed with the measurement error. You may make it correct | amend the measured value in a point.

  In the first embodiment, since the surface position of the outer edge portion of the wafer W is also measured in advance, high-precision focus / leveling control can be performed even when an edge shot is exposed.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described with reference to FIG. The exposure apparatus 100 according to the second embodiment differs from the first embodiment in the arrangement of a plurality of measurement points and the calculation of the surface shape information of the wafer W and the leveling control method in the surface position measurement apparatus 60. In the following, the description will be focused on differences from the exposure apparatus according to the first embodiment.

  FIG. 10 shows the arrangement of measurement points in the surface position measurement device 60. As shown in FIG. 10, in the second embodiment, the plurality of measurement points of the surface position measurement device 60 are arranged so as to surround the periphery of the exposure area IA in a triple manner. That is, the plurality of measurement points are a frame-shaped area MA1 as a first frame-shaped area surrounding the exposure area IA, a frame-shaped area MA2 as a second frame-shaped area surrounding the outside of the frame-shaped area MA1, and a frame-shaped area. Arranged in a frame-like region MA3 as a third frame-like region surrounding the outside of MA2. In the frame-like areas MA1 and MA3, the measurement points are arranged so as to surround the exposure area IA at a predetermined interval D in the same manner as the measurement point area MA shown in FIGS. 2 (A) and 2 (B). However, the frame-shaped region MA2 has a certain width, and within the frame-shaped region MA2, the measurement points are evenly arranged in a matrix. In the frame-like region MA2, the predetermined interval between the measurement points may be different from D. Here, the frame-like region means not a rectangular region surrounded by the frame but an outer edge region of the rectangular region surrounded by the frame.

  Further, the width of the frame of the frame-shaped area MA2 corresponds to the size of the exposure area IA. That is, when viewed from the exposure area IA, the width of the side located on the + X side and the −X side of the rectangular frame area MA2 in the X axis direction is equal to or larger than the width of the exposure area IA in the X axis direction. As viewed from IA, the width in the Y-axis direction of the sides located on the + Y side and the −Y side of the rectangular frame area MA2 is equal to or greater than the width of the exposure area IA in the Y-axis direction. That is, the frame-like area MA2 is an arbitrary direction in the XY plane with respect to the exposure area IA so that the size of the frame-like area MA2 in that direction is greater than or equal to the magnitude of the exposure area IA in that direction. Is set. By defining in this way, no matter which direction the wafer stage WST moves, the area on the wafer W that reaches the exposure area IA is always included in the frame area MA2 before the movement. Become.

  As shown in FIG. 10, the distances from the center of the exposure area IA to the frame-like areas MA1 and MA2 (center lines passing through the center of the frame) and MA3 are a1, a2, a3, and Y-axis in the X-axis direction, respectively. The directions are b1, b2, and b3. The a1, a2 and a3 are defined to be a2 = 2 · a1 and a3 = 3 · a1, and the distances b1, b2 and b3 are defined as b2 = 2 · b1 and b3 = 3 · b1. It is prescribed to be. Due to these relationships, the following relationship occurs between the frame-shaped regions MA1 to MA3 and the exposure region IA.

  In FIG. 11, the frame-shaped area WA1 on the wafer W having the same size as the frame-shaped area MA1 is shown by a dotted line across a part of the frame-shaped areas MA1 and MA3. As shown in FIG. 11, when the frame-shaped area WA1 is arranged so as to extend over a part of the frame-shaped areas MA1 and MA3, a part of the frame-shaped area WA1 includes the upper right apex and the frame shape of the frame-shaped area MA1. It is defined to coincide with a part of the upper right side of the area MA2. That is, the surface position of a point on the frame-shaped area WA1 on the wafer W can be measured at the measurement point of the surface position measuring device 60 arranged at the apex of the frame-shaped area MA1. It becomes possible to measure the surface position of a point on the frame-like area WA1 at a measurement point at a part of the upper right side of the paper.

  Further, it is assumed that the region IA ′ with respect to the frame-shaped region WA1 has the same positional relationship as that of the exposure region IA with respect to the frame-shaped region MA1. In FIG. 11, the region IA ′ is indicated by a one-dot chain line. As shown in FIG. 11, when the frame-shaped area WA1 is arranged so as to extend over a part of the frame-shaped areas MA1 and MA3, the area IA ′ is completely contained in the frame-shaped area MA2. This is the same even when the frame-shaped area WA1 is arranged to extend over a part of the frame-shaped areas MA1 and MA3 other than the position shown in FIG. That is, if the frame-shaped area WA1 is arranged so as to extend over a part of the frame-shaped areas MA1 and MA3, the area IA ′ is included in the frame-shaped area MA2. In other words, in the second embodiment, when a part of the frame-shaped area MA2 and the exposure area IA are overlapped, some measurement points (at least 3 not on the same straight line) of the frame-shaped areas MA1 and MA3. A plurality of measurement points are arranged so that one measurement point) overlaps the measurement point of the frame-shaped area WA1.

  12A to 12C show how the area IA ′ moves to the exposure area IA by the movement of the wafer stage WST.

  As shown in FIG. 12A, the area IA ′ on the wafer W located outside the frame-shaped area MA3 is changed to the exposure area IA in the lower left direction of the drawing by the movement of the wafer stage WST indicated by the arrow. Proceed toward. Then, as indicated by a dotted line in FIG. 12B, the area IA ′ on the wafer W coincides with a part of the frame-shaped area MA2 of the measurement point, and the frame-shaped area WA1 on the wafer W becomes the same. Then, it is located at a position (same position as the frame-shaped area WA1 shown in FIG. 11) over a part of the frame-shaped areas MA1 and MA3.

  Then, by further movement of wafer stage WST, area IA ′ on wafer W reaches exposure area IA as shown in FIG. 12C, and frame-shaped area MA1 and frame-shaped area WA1 on wafer W are reached. Will match.

  Thus, before the area IA ′ on the wafer W reaches the exposure area IA due to the movement of the wafer stage WST, the frame-shaped area WA1 and the area IA ′ always pass through the areas MA1 to MA3. In the second embodiment, when the frame-shaped region WA1 and the region IA ′ pass through the frame-shaped regions MA1, MA2, and MA3, the relationship between the relative surface positions of the frame-shaped region WA1 and the region IA ′ is measured. Then, from the measurement result, the surface position of the wafer W when the area IA ′ reaches the exposure area IA is controlled. Below, the control method is demonstrated.

As shown in FIG. 13, when the frame-shaped area WA1 on the wafer W is located across the frame-shaped areas MA1 and MA3, the measurement included in the set of measurement points on the frame-shaped area WA1. Let the point be S _s '. In FIG. 13, among the measurement points S _s ′, the measurement point at the upper right vertex of the frame-like region MA1 (referred to as measurement point S ₁ ′) and the measurement point at the upper side of the frame-like region MA3 (measurement point S _2). 'And a measurement point (measurement point S ₃ ') on the right side of the frame-like region MA3 are representatively shown. When the position coordinates of the center point of the area IA ′ at this time are (x, y), the position coordinates of the respective measurement points S ₁ ′ to S ₃ ′ are (x + x _s1 ′, y + y _s1 ′), ( x + _xs2 ′, y + _ys2 ′) and (x + _xs3 ′, y + _ys3 ′).

FIG. 14A schematically shows an example of measurement values of the surface position of the wafer W at the measurement points S ₁ ′, S ₂ ′, S ₃ ′. The measured values of the surface position of the wafer W at the measurement points S ₁ ′, S ₂ ′, S ₃ ′ are h _{s1 ′} (x + x _s1 ′, y + y _s1 ′) and h _{s2 ′} (x + x _s2 ′, y + y _s2 ′), respectively. ), H _{s3 ′} (x + x _s3 ′, y + y _s3 ′). FIG. 14A shows the measured values h _{s1 ′} (x + x _s1 ′, y + y _s1 ′) and h _{s2 ′} of the surface position at the _three measurement points S ₁ ′, S ₂ ′, S _{3 ′.} (X + x _s2 ′, y + y _s2 ′), h _{s3 ′} (x + x _s3 ′, y + y _s3 ′), the plane p (x, y; h _sj ′ (x + x _sj ′, y + y _sj ′)) is also shown. ing.

FIG. 14B shows the surface position h _s (x, y) of the wafer W measured at the measurement point of the frame-shaped region MA2 corresponding to the center of the region IA ′ on the wafer W. FIG. 14C shows the difference T (x, y) between the surface position h _s (x, y) and the plane p at that point. This difference T (x, y) is expressed by the following equation.

本第２の実施形態では、平面ｐを算出して、上記式（６）を用いてＴ（ｘ，ｙ）を算出し、その計測点Ｓ₁’、Ｓ₂’、Ｓ₃’の位置座標（ｘ＋ｘ_s1’，ｙ＋ｙ_s1’）、（ｘ＋ｘ_s2’，ｙ＋ｙ_s2’）、（ｘ＋ｘ_s3’，ｙ＋ｙ_s3’）とともに、このＴ（ｘ、ｙ）を、不図示の記憶装置に格納しておく。

In the second embodiment, the plane p is calculated, T (x, y) is calculated using the above equation (6), and the position coordinates of the measurement points S ₁ ′, S ₂ ′, S ₃ ′ are calculated. Along with (x + x _s1 ′, y + y _s1 ′), (x + x _s2 ′, y + y _s2 ′), (x + x _s3 ′, y + y _s3 ′), this T (x, y) is stored in a storage device (not shown). .

Consider the case where wafer stage WST further moves and frame-like area WA1 on wafer W coincides with frame-like area MA1 as shown in FIG. A set of measurement points in the frame-like region MA1 is set as S _sj ″. When the position coordinate of the center of the exposure area IA at this time is (x, y), the main control apparatus 20 has position coordinates (x + x _s1 ′, y + y _s1 ′), ( x + x _s2 ′, y + y _s2 ′) and (x + x _s3 ′, y + y _s3 ′) are searched for measurement points S ₁ ″, S ₂ ″, S ₃ ″. Then, the surface position h _{s1 ″} (x + x _s1 ′, y + y _s1 ′), h of the wafer W at the measurement points S ₁ ″, S ₂ ″, S ₃ ″ sent from the surface position measuring device 60. _{s2 ″} (x + _xs2 ′, y + _ys2 ′) and _{hs3 ″} (x + _xs3 ′, y + _ys3 ′) are acquired. FIG. 16A shows a schematic plane q (x, y; h) of the wafer W formed by the measurement values of the surface positions at these three measurement points S ₁ ″, S ₂ ″, S ₃ ″. _sj '' (x + _xsj ', y + _ysj ')) is shown. The main controller 20 calculates the plane q from the measured values at these three measurement points S ₁ ″, S ₂ ″, and S ₃ ″.

  Since the planes p and q are measured values of the surface position of the wafer W measured at three identical points on the wafer W, the surface position of the wafer W at the center of the exposure area IA is to be estimated. The planes p and q may be superposed. Specifically, if the difference T (x, y) from the plane p at the center of the area IA ′ on the wafer W is added to the plane q using the following equation, the position indicated by the value is the surface of the wafer W. It can be an estimated value of the position.

図１６（Ｂ）には、このときの露光領域ＩＡの中心（ｘ，ｙ）における平面ｑ（ｘ，ｙ）の値が示されている。この場合、図１６（Ｃ）に示されるように、この露光領域ＩＡの中心（ｘ，ｙ）における平面ｑ（ｘ，ｙ）を基準として、Ｔ（ｘ，ｙ）が加算されることにより、露光領域ＩＡの中心（ｘ，ｙ）におけるウエハＷの面位置が推定される。

FIG. 16B shows the value of the plane q (x, y) at the center (x, y) of the exposure area IA at this time. In this case, as shown in FIG. 16C, T (x, y) is added with reference to the plane q (x, y) at the center (x, y) of the exposure area IA. The surface position of the wafer W at the center (x, y) of the exposure area IA is estimated.

In the second embodiment, since leveling control of the wafer W is also performed, not only the surface position of the center of the exposure area IA (the center of the area IA ′) but also the wafer W at other points in the exposure area IA. The surface position is also estimated. FIG. 17A shows the measurement value h _s (x + Δx, y + Δy) at a measurement point corresponding to one point (x + Δx, y + Δy) among the four corner points of the exposure area IA. The main controller 20 calculates the difference T (x, y, Δx, Δy) between the plane p and the measurement value h _s (x + Δx, y + Δy) at the point of the area IA ′ on the wafer W using the following equation. And stored in a storage device (not shown).

図１７（Ｂ）には、平面ｑ（ｘ＋Δｘ，ｙ＋Δｙ）を基準として、この露光領域ＩＡ内の地点（ｘ＋Δｘ，ｙ＋Δｙ）におけるＴ（ｘ＋Δｘ，ｙ＋Δｙ）が加算され、露光領域ＩＡの中心（ｘ＋Δｘ，ｙ＋Δｙ）におけるウエハＷの推定面位置の一例が示されている。

In FIG. 17B, T (x + Δx, y + Δy) at a point (x + Δx, y + Δy) in the exposure area IA is added with reference to the plane q (x + Δx, y + Δy), and the center (x + Δx, An example of the estimated surface position of the wafer W at y + Δy) is shown.

  The main controller 20 also estimates the surface position of the wafer W using the above formula (8) for the other three points of the four corners of the exposure area IA, and the center of the exposure area IA and the wafer W at the four corners. Wafer W (wafer stage WST) is driven by driving actuators 41A-41C constituting wafer stage drive unit WSC so that the estimated surface position matches the best imaging plane of projection optical system PL within the depth of focus. Autofocus / leveling control.

  In the second embodiment, the calculation of the planes p and q has been described as if they were obtained from the measurement results at three measurement points. However, in reality, the planes are measured using four or more measurement points. p and q may be calculated. In this case, the planes p and q may be obtained statistically (for example, by a method such as least square approximation) based on the measurement results of those measurement points. The same applies to the case where the estimated surface position of the wafer W corresponding to the exposure area IA is calculated based on T (x, y) and T (x + Δx, y + Δy).

  As described above in detail, according to the second embodiment, the plurality of measurement points of the surface position measuring device 60 surround the exposure area IA in triplicate, and the wafer is formed by the measurement points arranged in triplicate. Since the surface positions at different positions of W can be simultaneously measured, three-dimensional data of the surface of the wafer W can be acquired. Accordingly, unlike the first embodiment, the rigidity of wafer stage WST is relatively weak and its distortion is large, and the measurement points of wafer interferometers 18XY and 18Z, the measurement points of surface position measurement device 60, That is, even if the positional relationship with the surface of the wafer W cannot be ignored, the surface shape of the wafer W can be accurately measured.

  Further, according to the second embodiment, the plurality of measurement points of the surface position measuring device 60 include the frame-shaped area MA1 that surrounds the outside of the exposure area IA, and the frame-shaped area MA2 that surrounds the outside of the frame-shaped area MA1. And a frame-shaped region MA3 that surrounds the outside of the frame-shaped region MA2. Then, in any direction in the XY plane with reference to the exposure area IA, the size of the frame-shaped area MA2 in the direction is equal to or larger than the size of the exposure area IA in the direction, and a part of the frame-shaped area MA2 and the exposure area When the IA is overlapped, the surface position measuring device 60 is arranged such that at least three measurement points that are not on the same straight line included in the frame-like region MA1 and the frame-like region MA3 overlap with the measurement points of the frame-like region MA1. A plurality of measurement points are arranged. In this way, the three-dimensional surface shape around a certain area on the wafer W that reaches the exposure area IA can always be obtained from the measurement results of the measurement points of the frame-shaped areas MA1, MA2, and MA3. Therefore, the surface position of the area on the wafer W that coincides with the exposure area IA can be estimated from the measurement value of the surface position of the wafer W measured at the current measurement point of the frame-shaped area MA1.

  Also in the second embodiment, the measurement result of the surface position measurement device 60 is corrected in consideration of the reliability of the acceleration of the wafer stage WST at the time of measurement and the time required for the measurement. Of course, it is also good. For example, when the same point on the wafer W is measured at a plurality of different measurement points, the surface position of the point can be calculated by a weighted average based on the reliability of the measurement value.

  In the second embodiment, the arrangement interval of the measurement points in the frame-like regions MA1 and MA3 is the same D. However, for example, the arrangement of the measurement points may be as shown in FIG. In FIG. 18, the measurement points in the frame-shaped region MA3 are indicated by white circles and black circles. That is, in this example, the arrangement density of the measurement points in the frame-shaped region MA3 is sparse, and the measurement points are arranged so that they are not substantially continuous but isolated. Even in such an arrangement, when the exposure area IA and a part of the frame-shaped area MA2 are overlapped with each other, the frame-shaped pattern coincides with at least three measurement points on the frame-shaped area MA1 that are not on the same straight line. There are at least three measurement points on the area MA1 and the frame-shaped area MA3. From this point of view, measurement points indicated by white circles in FIG. 18 can also be omitted. However, it is not desirable to arrange the measurement points of the frame-like region MA1 sparsely like the frame-like region MA3. Since the measurement points for calculating the plane q vary depending on the moving direction of the wafer stage WST, it is desirable to arrange the measurement points substantially continuously in the frame-like region MA1.

  As shown in FIG. 19, when the exposure apparatus 100 is a step-and-repeat type exposure apparatus that performs batch exposure instead of the step-and-scan type, the exposure area IA has a large area. Therefore, it is necessary to further increase the width of the frame-shaped region MA2.

  As described above, by arranging a plurality of measurement points so as to surround the exposure area IA in a triple manner, it is possible to pre-read the surface shape of the wafer W and control the surface position of the wafer. Various modifications can be made to the triple arrangement of measurement points. FIG. 20 shows a modification of the triple arrangement of the measurement points. In this arrangement, the size of the second largest frame-shaped area MA2 is not such that the exposure area IA is completely included. Like the frame-shaped areas MA1 and MA3, the exposure area IA is not formed. Measurement points are arranged so as to surround them in a single layer. In this way, since the area of the region where the measurement points are arranged can be reduced, the surface position measuring device 60 can be downsized and hardware restrictions can be reduced.

Relates the X-axis direction, with respect to the center of exposure area IA, the distance to the frame-shaped area MA1 and a _1, a distance to the frame-shaped area MA2 as a _2, a distance to the frame-like area MA3 with a ₃ . Also relates to the Y-axis direction, with respect to the center of exposure area IA, the distance to the frame-shaped area MA1 and b _1, a distance to the frame-shaped area MA2 and b _2, the distance to the frame-like area MA3 b ₃ And In this case, the relationship between a _{1 to} a ₃ and b _{1 to} b ₃ is defined as follows:

すなわち、Ｘ軸方向に関して隣接する領域の間隔はＴ_aであり、Ｙ軸方向に関して隣接する領域の間隔はＴ_bとなっている。また、Ｘ軸方向に関する露光領域ＩＡの中心から領域ＭＡ１までの距離ａ₁は、Ｔ_aの整数倍に規定されており、Ｙ軸方向に関する露光領域ＩＡの中心から領域ＭＡ１までの距離ｂ₂は、Ｔ_bの整数倍に規定されている。

That is, the interval of the regions adjacent in the X-axis direction is T _a, the interval between areas adjacent in the Y-axis direction is a T _b. The distance a ₁ from the center of exposure area IA in the X-axis direction to the region MA1 is defined to an integral multiple of T _a, the distance b ₂ from the center of exposure area IA in the Y-axis directions to an area MA1 is , _Tb is an integral multiple of Tb.

As the wafer stage WST moves under the plurality of measurement points arranged in this manner, the point (x _i , y _i ) of the wafer W coincides with the measurement point as in the first embodiment. In this case, the surface position of the point (x _i , y _i ) is measured. The measured values of the surface positions at a plurality of points on the wafer W that are simultaneously measured at this time are represented by h _t (x _i , y _i ), respectively. The main controller 20 stores such a plurality of points (x _i, y _i) which is measured simultaneously with the measurement values h _t (x _i, y _i) of the surface position of the the storage device (not shown).

  However, unlike the first embodiment, when the surface position of the wafer W cannot be measured at the same time at at least four measurement points, the main controller 20 converts the measurement value to the surface shape of the wafer W. It is not used for calculation. This is because when only three measurement points are obtained at the same time, measurement results described later cannot be connected. For example, in the case of the arrangement of measurement points as shown in FIG. 20, at the time when measurement of the wafer surface position is possible at one measurement point on one side of the area MA3 and at least one measurement point on the area MA2. If measurement is started, it is possible to obtain measurement values of the surface positions of four or more measurement points without fail.

21A and 21B show a part of the frame-like areas MA1 to MA3 among a plurality of measurement points in an enlarged manner, and three measurement points are shown for each of the areas MA1 to MA3. Has been. In FIG. 21A, when the wafer stage WST is located at a certain position, the points (x _i , y _i ) of the wafer W measured at the three measurement points in the areas MA1 to MA3 are indicated by white circles. ing. The position coordinates of these points are assumed to be (x _i , y _i ) (i is a natural number). The main controller 20 stores the measured value h _t (x _i , y _i ) of the surface position of the point indicated by the white circle in a storage device (not shown). FIG. 22 shows an example of a surface formed by the measurement values h _t (x _i , y _i ) of the surface position.

Thereafter, the wafer stage WST is to moved by T _b in the -Y direction. In FIG. 21B, points on the wafer W measured at three measurement points in the frame-like regions MA1 to MA3 after the movement of the wafer stage WST are indicated by x. Let this point be (x _i ', y _i '). Main controller 20 stores the measured value h _{t + 1} (x _i ′, y _i ′) of the surface position of the point indicated by × in the storage device.

Note that in FIG. 21B, the points (x _i , y _i ) measured in FIG. 21A are indicated by circles as they are. As shown in FIG. 22 (B), since the wafer stage WST is moved in the Y-axis direction interval T _b in the Y-axis direction between are arranged measurement points region, indicated by both the circle and × There is a point. That is, a common point exists between the point (x _i , y _i ) and the point (x _i ′, y _i ′). Moreover, these points include at least three points that are not on a straight line. Therefore, the measurement result of the surface position of the point (x _i , y _i ) measured in FIG. 21A and the surface position of the point (x _i ′, y _i ′) measured in FIG. Measurement results can be connected and linked as a measurement result of one surface position. In FIG. 22, the surface formed by the measured values h _t (x _i , y _i ) at the point (x _i , y _i ) shown in FIG. 21A and the point ( x _i ', y _i') measured value at _{h t + 1 (x i '} , y i' is the plane formed by) are shown schematically. As shown in FIG. 22, the measurement values of the surface positions measured at a common point among the point (x _i , y _i ) and the point (x _i ′, y _i ′) are the same. For example, the connecting surfaces can be formed by matching the surface formed by the dots with the surface formed by the round dots.

  As described above, as the wafer stage WST moves, the surface position at the same point is measured at a plurality of different measurement points. Therefore, when there are measurement results at at least three points that are not on the same straight line. Can connect and link those measurement results. If the connecting surface obtained as a result of this connection is a surface shape map of the wafer W, a surface shape map of the region of the wafer W that has passed through the region where the measurement points are arranged can be created.

  The processing procedure of the main controller 20 when creating this surface shape map will be described. When main controller 20 acquires the measurement results of the surface positions of four or more wafers W measured simultaneously, a map including the measurement results of the surface positions at at least three common points is stored in the storage device. Check whether it is already stored. When there is no such map, main controller 20 stores the set of measurement results acquired this time (this is a small map) as a new map, but at least three common points. If there is a map containing the measurement result of the surface position at, read the map, connect the map and the small map acquired this time, and store the surface shape map of the wafer W created by the connection Store in the device.

FIG. 23 shows an example of the surface shape maps H (x _i , y _i ) and H ′ (x _i ′, y _i ′) of the wafer W created by connecting the surfaces of such measurement results. Yes. The intervals in the X-axis and Y-axis directions at the points of the two surface shape maps H (x _i , y _i ) and H ′ (x _i ′, y _i ′) It depends on the axial distances T _a and T _b . As described above, if the entire surface of the wafer W is measured by the surface position measuring device 60, several surface shape maps can be created. As a result, these surface shape maps are obtained from the measurement point regions MA1 to MA3. The surface shape map is defined by the intervals T _a and T _b .

FIG. 23 also shows a measurement point area MA1 of the surface position measurement device 60. In FIG. 23, the point measured in the area MA1 corresponds to the surface shape map H (x _i , y _i ) instead of the surface shape map H ′ (x _i ′, y _i ′). The apparatus 20 reads the surface shape map H (x _i , y _i ) from the storage device, estimates the surface position of the wafer W using the surface shape map H (x _i , y _i ), and determines the surface position. Perform focus / leveling control. If the wafer W moves and the point corresponding to the measurement point region MA1 is a point on the surface shape map H ′ (x _i ′, y _i ′), this time, the surface shape map H ′ (x _i ′, y _i ′) may be read and used.

  Also in this case, since the measurement points of the surface position measuring device are arranged so as to surround the exposure travel area IA, a surface shape map (small map) is connected along the traveling direction of the wafer stage WST. I can go. Therefore, the surface position of the wafer W to be exposed can always be estimated before the exposure regardless of the traveling direction of the wafer stage WST.

Note that the smaller the distances T _a and T _b between the measurement point regions, the smaller the size of the surface position measuring device 60, which is advantageous in terms of hardware configuration and provides a fine surface shape map. Will be able to create. However, in the method of creating a surface shape map by connecting small maps as described above, errors due to the connection may be accumulated, so the measurement point region is considered in consideration of the tolerance of these errors. It is desirable to determine the distance.

  As described above, the surface position measurement apparatus having the measurement point arrangement as shown in FIG. 20 can accurately measure the surface shape of wafer W regardless of the rigidity of wafer stage WST. This is because the surface shape map is created by connecting the measurement results using the measurement values of three measurement points that are not on the same straight line, so that the Z position and pitching of the wafer stage WST are generated. This is because it is not necessary to consider the amount and rolling amount.

  However, when determining the surface shape map, if the pitching amount and rolling amount of wafer stage WST are controlled and the inclination of wafer stage WST (Z / leveling stage WS2) is zero, the surface position measuring device It is also possible to reduce the number of 60 measurement points.

  FIG. 24A shows the arrangement of measurement points of the surface position measurement device 60 that is possible in such a case. As shown in FIG. 24A, the plurality of measurement points of the surface position measurement device 60 are arranged so as to double surround the exposure area IA. That is, the plurality of measurement points are a frame-shaped area MA1 ′ as a first frame-shaped area surrounding the exposure area IA, and a frame-shaped area MA2 ′ as a second frame-shaped area surrounding the outside of the frame-shaped area MA1 ′. Respectively. In the frame-shaped region MA2 ′, the measurement points are arranged in one row at a predetermined interval D, as in the measurement point region MA shown in FIG. 2A, but the frame-shaped region MA1 ′ Since it has a width, a plurality of measurement points are evenly arranged in a matrix within the region. The predetermined interval between the measurement points in the frame-shaped region MA1 'may not be D.

  Further, the frame width of the frame-shaped area MA1 'corresponds to the size of the exposure area IA. That is, when viewed from the exposure area IA, the width in the X-axis direction of the side located on the + X side and the −X side of the frame-shaped area MA1 ′ is equal to or larger than the width in the X-axis direction of the exposure area IA. As viewed from IA, the width of the side located on the + Y side and the −Y side of the frame-shaped region MA1 ′ in the Y-axis direction is equal to or greater than the width of the exposure region IA in the Y-axis direction. That is, the frame-shaped area MA1 ′ is an arbitrary direction in the XY plane with the exposure area IA as a reference, and the size of the frame-shaped area MA1 ′ in the direction is greater than or equal to the size of the exposure area IA in the direction. Is set to By defining in this way, regardless of the direction of wafer stage WST, the area on wafer W that reaches exposure area IA is always included in frame-shaped area MA1 '.

  In FIG. 24A, the frame-shaped area WA1 of the wafer W that coincides with a part of the frame-shaped area MA2 'and has the same size as the frame-shaped area MA1' is indicated by a thick dotted line. Further, it is assumed that the area IA ′ on the wafer W has the same positional relationship as that of the exposure area IA with respect to the frame-shaped area MA1 ′. In FIG. 24A, this region IA 'is indicated by a thin dotted line. As shown in FIG. 24A, when the area IA 'and the frame-shaped area MA1' are overlapped, the frame-shaped area WA1 coincides with a part of the frame-shaped area MA1 '. This is the same even when the region IA 'is included in a part of the frame-shaped region MA1' other than the position shown in FIG. That is, if the region IA ′ is arranged so as to coincide with a part of the frame-like region MA1 ′, the measurement points on the frame-like region MA2 ′ may coincide with some measurement points of the frame-like region MA1 ′. become.

Therefore, here, when the region IA ′ is located at the position shown in FIG. 24A, the measurement point on the frame-like region MA2 ′ and the region IA ′ included in the frame-like region MA1 ′. The surface position of the wafer W at the measurement point coinciding with is measured. FIG. 24C shows the measurement value h _{s ′} (x + x _{s ′,} y + y _{s ′} ) at the measurement point S _s ′ on the frame-shaped region MA1 ′. The main control device 20 acquires the measurement value h _s (x, y) of the surface position at the measurement point in the frame-like area MA1 ′ corresponding to the center of the area IA ′, and h _{s ′} (x + x _{s ′,} y + y). _{s ′} ) and h _s (x, y) are determined as T (x, y).

FIG. 24D shows a state where the area IA ′ on the wafer W has moved to the exposure area IA. Main controller 20 searches for measurement point S _{s ″} on frame-like region MA1 ′ corresponding to measurement point S _{s ′} at which the measurement value shown in FIG. 24C is measured, and the surface position at the measurement point. Measured value h _{s ″} (x + x _{s ′,} y + y _{s ′} ) is acquired. Then, main controller 20 estimates the surface position of wafer W at the center of exposure area IA by adding this measured value h _{s ″} (x + x _{s ′,} y + y _{s ′} ) to T (x, y). can do.

  FIG. 25A shows a modification of the double arrangement of measurement points. In this measurement point arrangement, the inner frame-shaped measurement point area MA1 ′ does not have a size that covers the entire exposure area IA, and, like the frame-shaped measurement point area MA2 ′, the exposure area IA is single-layered. Measurement points are arranged to surround

  With respect to the X-axis direction, with reference to the center of the exposure area IA, the distance to the frame-shaped area MA1 'is a1, and the distance to the frame-shaped area MA2' is a2. Further, with respect to the Y-axis direction, the distance to the frame-shaped area MA1 'is b1, and the distance to the frame-shaped area MA2' is b2, with the center of the exposure area IA as a reference. It is defined that a1 is an integer multiple of a2-a1, and b1 is an integer multiple of b2-b1.

  Even if a plurality of measurement points are arranged in this way, if it is guaranteed that the inclination of wafer stage WST (Z / leveling stage WS2) is zero, wafer W can be obtained by connecting measurement results. A surface shape map can be created. For example, as shown in FIG. 25 (B), when there are two measurement results including surface position information of at least one same point, the two measurement values at that point are matched to each other. Measurement results can be connected.

  Further, in each of the above-described actual embodiments, the measurement device that measures the surface position of the wafer W for creating the surface shape map of the wafer W has a plurality of measurement points arranged so as to surround the field of view of the projection optical system PL. Although only the surface position measuring device 60 is provided, a measuring device for measuring the surface position of the wafer W may be provided. For example, a measurement apparatus in which a plurality of measurement points are arranged so as to surround the alignment detection system AS or a measurement apparatus that measures the surface shape of the wafer W with a Fizeau interferometer is provided. The shape may be measured. In this case, the measurement point arrangement of the surface position measurement device 60 surrounding the field of the projection optical system PL can be as shown in FIG. According to this, a plurality of measurement points of the surface position measuring device 60 are arranged radially with the exposure area IA as the center. If the surface shape of the wafer W has already been measured by another measuring device and a surface shape map has been created, the surface position corresponding to the measurement point of the surface position measuring device 60 and the point corresponding to the exposure area IA Since the positional relationship between the surface positions of the wafers W is known, the surface position of the wafer W coincident with the exposure area IA is determined from the measurement result of the surface position of the wafer W measured at each measurement point of the surface position measuring device 60 during exposure. The surface of the wafer W can be adjusted within the depth of focus to the best imaging plane of the projection optical system PL. The method for estimating the surface position of the wafer W corresponding to the exposure area IA can be the same as the method for estimating the surface position in the second embodiment.

  By the way, in the step-and-scan type exposure apparatus, since the width of the exposure area IA is short in the scanning direction (Y-axis direction), the leveling requirement accuracy in this direction may not be higher than that in the non-scanning direction. Therefore, in this case, it is possible to perform only leveling control of the surface position of the wafer W in the X-axis direction during exposure.

  FIG. 27A shows an arrangement example of measurement points of the surface position measurement device 60 at this time. As shown in FIG. 27A, these measurement points are arranged on a frame-shaped measurement point area MA that substantially surrounds the exposure area IA. In this measurement point area MA, two areas (MAY1 and MAY2) in which measurement point sequences along the scanning direction (Y′-axis direction) are formed, and measurement point sequences along the X′-axis direction are formed. The two areas (MAX1 and MAX2) substantially surround the exposure area IA. The areas MAY1 and MAY2 are arranged at a distance a in the X-axis direction with respect to the center of the exposure area IA, and the areas MAX1 and MAX2 have a distance b with respect to the center of the exposure area IA. It is arranged at each position.

  A method of measuring the surface shape of the wafer W and adjusting the surface position in this arrangement will be described. In FIG. 27A, the next shot area SA to be exposed is indicated by a dotted line. That is, here, in order to expose the shot area SA, a surface shape map of the wafer W is created based on the measurement results of the measurement points in the areas MAX1 and MAX2.

  The lengths of the regions MAX1 and MAX2 in the X-axis direction are 2a ′ (a ′> a), and are arranged in line symmetry with respect to the Y ′ axis. Assuming that the center position of the areas MAX1 and MAX2 is (x ′, y ′), the position coordinates (x, y) of the measurement points in the areas MAX1 and MAX2 are x∈ (x′−a ′ + a, x ′ + a). '-A), y = y'.

  In the state shown in FIG. 27A, since a part of the shot area SA is on the area MAX1, the surface position of the part can be measured by a plurality of measurement points on the area MAX1. . In FIG. 27A, a point on the wafer W that is on the area MAX1 and passes through the center of the exposure area IA in a part of the shot area SA is indicated by a black circle. In addition, two points on the region MAX1 that are separated from this point by a distance a in the X-axis direction are indicated by white circles. The main controller 20 measures the measured value h (x, y) of the surface position of the wafer W at the measurement point indicated by the black circle and the surface position of the wafer W at the two measurement points indicated by the white circle. The values h (x−a, y) and h (x + a, y) are acquired and the following equation is calculated.

すなわち、主制御装置２０は、黒丸で示される計測点での面位置の計測値と、白丸で示される計測点での面位置の計測値の平均との差Ｔ（ｘ，ｙ）を算出する。

That is, main controller 20 calculates a difference T (x, y) between the measurement value of the surface position at the measurement point indicated by the black circle and the average of the measurement values of the surface position at the measurement point indicated by the white circle. .

  Note that in order to perform leveling control in the X-axis direction of the wafer surface that coincides with the exposure area IA, the surface position at a point separated by Δx in the X-axis direction from the point (x, y) indicated by the black circle is also measured. Then, using the following equation, the difference T (x, y, Δx) between the measured value h (x + Δx) of the surface position at the measurement point and the average of the measured values of the surface position at the measurement points indicated by white circles. Also calculate.

  Then, it is assumed that the measured area on the wafer W reaches the exposure area IA as shown in FIG. 27B due to the movement of the wafer stage WST. At this time, main controller 20 measures the surface position of wafer W at the measurement points on areas MAY1 and MAY2 where the Y (Y ′) position is the same as exposure area IA, and T (( x, y) and T (x, y, Δx) are added to estimate the surface position of the wafer W at each point (x, y), (x + Δx, y), and this estimated surface position is used. Then, leveling control of the surface position of the wafer W in the X-axis direction is performed.

  Similarly, when the advancing direction of wafer stage WST is the + Y direction and shot area SA enters exposure area IA from the −Y direction, in measurement point area MAX2, the X-axis direction in the shot area If the surface shape is measured, the same surface position control of the wafer W as described above can be realized.

  By the way, in this arrangement, the distance b from the center of the exposure area IA to the side parallel to the X axis of the measurement point area MA is defined to be shorter than the run distance of the wafer stage WST at the time of scan exposure. In this way, when scanning and exposing one shot area, the shot area SA to be exposed is positioned outside the measurement point area MA with the wafer stage WST positioned at the scanning start position. Therefore, it becomes possible to always measure the inclination of the surface position of the wafer W in the shot area SA in the X-axis direction in either of the areas MAX1 and MAX2.

  Further, for example, a plurality of shot areas are alternately scanned (for example, after scanning exposure of a shot area in which the wafer stage WST is scanned in the + Y direction), the wafer stage WST is moved in the −Y direction in the adjacent shot area. When performing the scanning exposure), the wafer stage WST may enter the exposure area IA from an oblique direction after the start of acceleration, but the measurement point areas MAX1 and MAX2 are in the X-axis direction. Since it is expanded, the shot area can be reliably captured, and the surface shape in the X-axis direction of the wafer W in the shot area can be measured.

  If the areas MAX1 and MAX2 are expanded in the X-axis direction in this way, the surface shape in the shot area adjacent to the shot area SA can be measured in advance during the scan exposure of the shot area SA. it can. In particular, if a′-a is made the same as the width of the shot area in the X-axis direction, the surface shape of the entire adjacent shot area can be measured in advance. In that sense, the larger a ', the better. In addition, when performing such prior measurement, it is possible to consider the reliability of the measurement value and the like as in the first embodiment.

  In parallel with the areas MAX1 and MAX2, three measurement point areas capable of measuring the surface position are arranged at regular intervals (6 in total, three at each end in the Y-axis direction). For example, similarly to the second embodiment, leveling control of the surface position of the wafer W in the Y-axis direction can be performed.

In the above-described first and second embodiments, so as to completely surround the exposure area IA, it was arranged measurement points S ₁ to S _n, the present invention is not limited thereto. For example, as shown in FIGS. 28A and 28B, measurement points may be arranged on two sides facing each other across the exposure area IA. In the arrangement example shown in FIG. 28A, a measurement point area MA extending in the X ₁ (hereinafter referred to as X) axial direction is viewed in the scanning direction (that is, the direction in which the wafer W moves) as viewed from the exposure area IA. They are arranged on both sides in a certain Y ₁ (Y) axis direction (that is, on the + Y side and the −Y side across the exposure area IA). In the arrangement example shown in FIG. 28B, the measurement point area MA extending in the Y-axis direction is viewed from the exposure area IA so that the exposure area IA is sandwiched in the X-axis direction. It is arranged on each side.

Thus, the measurement points S ₁ to S _n, FIG. 28 (A), be arranged as shown in FIG. 28 (B), similarly to the embodiment described above, from the measurement results of the surface position measuring device Of course, a surface shape map of the wafer W can be created. 2A, the measurement point arrangement shown in FIG. 28A and FIG. 28B is a rectangular frame (measurement point region MA in FIG. 2A). Of these four sides, it can also be regarded as measurement points arranged on two opposite sides.

  Further, as representatively shown in FIG. 29A, measurement points may be arranged on three sides of the four sides of the rectangular frame (measurement point region MA in FIG. 2A). . Note that, as shown in FIG. 29A, measurement point sequences are not provided on the + Y side, −Y side, and + X side of the exposure area IA, but on the + Y side, −Y side, −X side of the exposure area IA, It goes without saying that measurement point sequences may be provided on the + Y side, −Y side, + X side of the exposure area IA, and on the −Y side, + X side, and −X side of the exposure area IA.

  As another example, measurement points may be arranged on two sides orthogonal to each other among four sides of a rectangular frame (measurement point region MA in FIG. 2A).

In the example shown in FIG. 29B, measurement points are arranged on three X-ray segments arranged at equal intervals in the Y-axis direction on the −Y (−Y ₁ ) side with respect to the exposure area IA. Yes. The reason why the measurement point sequence is arranged on the −Y side of the exposure area IA is that the detection center FX of the alignment system AS is positioned in this direction, and + Y of the exposure area IA is performed during the alignment operation and the exposure operation. This is because the probability that each measurement point captures the surface of the wafer W is higher than the arrangement of measurement point sequences on the side, + X side, and −X side. This does not prevent the arrangement of a plurality of measurement point sequences on the + Y side, + X side, and −X side of the exposure area IA. Further, the number of measurement point sequences may be more than three, or may be one or two. The intervals between the measurement point sequences need not be equal.

  In each of the above embodiments, the working distance is short, and the case where the surface position of the wafer W that coincides with the field of view of the projection optical system PL and the exposure area IA cannot be directly measured has been described. In the case where the surface position of the positioned wafer W can be directly measured, a plurality of measurement points can be arranged as shown in FIGS. 30 (A) and 30 (B).

  In FIG. 30A, five measurement point arrangement areas extending in the X-axis direction are provided. These five measurement point regions are designated as MA1 to MA5, respectively. In this way, for example, when the advancing direction of wafer stage WST being scanned is the -Y direction, for example, the surface positions of wafer W are measured in areas MA1, MA2, and MA3, and measurement point areas MA1 and MA3 are measured. The relative relationship of the measurement result in the measurement point area MA2 with respect to the measurement result in is detected. When the area of the wafer W on which the surface shape is measured proceeds to the measurement point areas MA1, MA2, and MA3, the relative relationship between the measurement results described above and the measurement results of the measurement point areas MA2 and MA4 at this time. Can be used to estimate the surface position of the wafer W corresponding to the area MA3, that is, corresponding to the exposure area IA, and the surface position can be adjusted based on the estimation result.

Incidentally, FIG. 30 in the arrangement shown in (A), Y-axis direction the three placement area MA2~MA4 excluding the measurement point arrangement region of both ends, the shot area SA _n-1 adjacent to the shot area SA _n subject to exposure , SA _{n + 1} is extended in the X-axis direction. In this way, the surface shape of the wafer W corresponding to the next shot areas SA _n−1 and SA _{n + 1} to be exposed can be measured during the exposure of the shot area SA. As shown in FIG. 30B, when the measurement results of the wafer interferometers 18XY and 18Z are taken into consideration, it is a matter of course that only the area MA3 may cover the adjacent shot area.

  In each of the above-described embodiments, the frame-shaped measurement point arrangement region is an all-outer rectangular frame shape, but is not limited to this, and any shape can be used as long as it substantially surrounds the exposure region. It may be a frame, for example, a ring shape or a polygonal shape. However, selecting the rectangular frame supported by the side has various advantages such as easier calculation in the main controller 20.

  In the first embodiment, during the measurement of the surface position of the wafer W, the Z position of the wafer stage WST is constant, and both the pitching amount θx and the rolling amount θy are controlled to 0. The deviation from the reference Z position measured by the wafer interferometers 18XY and 18Z, the pitching amount θx, the rolling amount θy, and the like may be canceled.

  Various arrangements of measurement points of the surface position measurement device 60 are possible as described in the above embodiments. This arrangement depends on the wafer interferometer 18XY, depending on the rigidity of the wafer stage WST. It is desirable to select as appropriate according to the relationship between the wafer stage WST measured at 18Z and the surface position of the wafer W measured by the surface position measuring device 60. Here, an error model of measurement values measured by the wafer interferometers 18XY and 18Z can be expressed as the following equation.

ここで、ｗ_t（ｘ，ｙ）の地点（ｘ、ｙ）における計測誤差を示す。また、η₀は、この計測誤差に含まれる０次成分であり、η_x，η_yは、１次成分の係数を示し、ｒ（ｘ，ｙ）は、計測誤差に含まれる２次以上の成分を示す。

Here, the measurement error at the point (x, y) of w _t (x, y) is shown. Η ₀ is a zero-order component included in this measurement error, η _x , η _y indicates a coefficient of the first-order component, and r (x, y) is a second or higher order included in the measurement error. Ingredients are shown.

  Here, the second-order or higher-order component r (x, y) can be regarded as 0, but the other components cannot be regarded as 0, the arrangement of the surface position measuring device will be described in the second embodiment. Such a triple arrangement is desirable. Further, when the first-order or higher order component can be regarded as 0 but the 0th-order component cannot be regarded as 0, it is desirable to arrange as shown in FIGS. 24 (A) and 24 (B). In addition, when even the 0th-order component can be regarded as 0, it is desirable to arrange as shown in the first embodiment.

  Regardless of the measurement point arrangement, it is preferable to perform pre-measurement as long as the surface position of the wafer W can be measured. In this way, since a predetermined point on the wafer W can be measured a plurality of times, the surface position measurement accuracy is improved, and the weighted average based on reliability as described in the first embodiment is used. Surface position calculation and calibration are possible.

  In the above embodiments, the surface position of the wafer W is controlled by the attitude control of the Z / levelin stage WS2 by driving the actuators 41A to 41C. However, the present invention is not limited to this, and the position of the projection optical system PL is controlled. Anyway.

  In each of the above-described embodiments, the exposure apparatus employing the local liquid immersion method has been described. However, the present invention is also applicable to a standard exposure apparatus that does not immerse the front lens and the exposure surface with liquid. Of course you can. The present invention can be suitably applied to any exposure apparatus that requires a large projection optical system NA and requires a small working distance.

Further, in each of the above embodiments, the surface position of the wafer W is controlled based on the discrete surface shape map H (x _i , y _i ) as the surface shape information of the wafer W. By interpolating between (x _i , y _i ), a continuous value surface shape map H (x, y) in the XY plane is created, and based on the surface shape map H (x _i , y _i ) The surface position of the wafer W may be controlled.

In each of the above embodiments, ultrapure water (water) is used as the liquid, but the present invention is not limited to this. As the liquid, a safe liquid that is chemically stable and has a high transmittance of the illumination light IL, such as a fluorine-based inert liquid, may be used. As this fluorinated inert liquid, for example, Fluorinert (trade name of 3M, USA) can be used. This fluorine-based inert liquid is also excellent in terms of cooling effect. In addition, a liquid that is transmissive to the illumination light IL and has a refractive index as high as possible, and is stable with respect to the projection optical system and the photoresist applied to the wafer surface (eg, cedar oil) is used. You can also. Further, when the F ₂ laser is used as the light source, fomblin oil may be selected.

  In each of the above embodiments, the recovered liquid may be reused. In this case, a filter that removes impurities from the recovered liquid may be provided in the liquid recovery device, the recovery pipe, or the like. desirable.

  In each of the embodiments described above, the optical element closest to the image plane of the projection optical system PL is the front lens 91. However, the optical element is not limited to the lens, but the optical element of the projection optical system PL. It may be an optical plate (parallel plane plate or the like) used for adjusting characteristics such as aberrations (spherical aberration, coma aberration, etc.), or a simple cover glass. The optical element on the most image plane side of the projection optical system PL (the front lens 91 in each of the above embodiments) is a liquid (due to scattering particles generated from the resist by irradiation of the illumination light IL or adhesion of impurities in the liquid, etc. In each of the embodiments described above, the surface may become soiled by contact with water. For this reason, the optical element may be fixed to the lowermost part of the lens barrel 40 so as to be detachable (replaceable), and may be periodically replaced.

  In such a case, if the optical element in contact with the liquid is a lens, the cost of the replacement part is high and the time required for the replacement becomes long, leading to an increase in maintenance cost (running cost) and a decrease in throughput. . Therefore, the optical element that comes into contact with the liquid may be a plane parallel plate that is cheaper than the front lens 91, for example.

  In each of the above embodiments, the range in which the liquid (water) flows may be set so as to cover the entire projection area of the reticle pattern image (irradiation area of the illumination light IL), and the size thereof is arbitrary. Although it is good, in controlling the flow velocity, flow rate, etc., it is desirable to make the range as small as possible by making it slightly larger than the irradiation region.

  A projection optical system composed of a plurality of lenses and a projection unit PU are incorporated in the exposure apparatus main body, and the liquid supply / discharge unit 32 and the surface position measuring device 60 are attached to the projection unit PU. After that, by making optical adjustments, attaching a reticle stage and wafer stage WST consisting of a large number of machine parts to the exposure apparatus body, connecting wiring and piping, and further making general adjustments (electrical adjustment, operation check, etc.) The exposure apparatus of each of the above embodiments can be manufactured. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  In each of the above embodiments, 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 scope of the present invention is of course not limited thereto. That is, the present invention can be suitably applied to a step-and-repeat reduction projection exposure apparatus. The present invention can also be suitably applied to exposure in a step-and-stitch reduction projection exposure apparatus that combines a shot area and a shot area. The present invention can also be applied to a twin stage type exposure apparatus having two wafer stages.

  The use of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, but for example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern to a square glass plate, an organic EL, a thin film magnetic head, an image sensor (CCD, 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.

The light source of the exposure apparatus of each of the above embodiments is not limited to an ArF excimer laser light source, but a pulse laser light source such as a KrF excimer laser light source or an F ₂ laser light source, g-line (wavelength 436 nm), i-line (wavelength 365 nm). It is also possible to use an ultra-high pressure mercury lamp that emits such bright lines. In addition, a single wavelength laser beam oscillated from a DFB semiconductor laser or fiber laser is amplified by a fiber amplifier doped with, for example, erbium (or both erbium and ytterbium), and a nonlinear optical crystal is obtained. It is also possible to use harmonics that have been converted into ultraviolet light. The magnification of the projection optical system may be not only a reduction system but also an equal magnification or an enlargement system.

  In each of the above embodiments, the illumination light IL of the exposure apparatus is not limited to light with a wavelength of 100 nm or more, and it is needless to say that light with 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, a configuration in which scanning exposure is performed by synchronously scanning a mask and a wafer using arc illumination is conceivable.

  The present invention can also be applied to an exposure apparatus that uses a charged particle beam such as an electron beam or an ion beam. The electron beam exposure apparatus may be any of a pencil beam method, a variable shaped beam method, a cell projection method, a blanking aperture array method, and a mask projection method. For example, in an exposure apparatus that uses an electron beam, an optical system including an electromagnetic lens is used.

  For semiconductor devices, the step of designing the function and performance of the device, the step of manufacturing a reticle based on this design step, the step of manufacturing a wafer from a silicon material, and transferring the reticle pattern to the wafer by the exposure apparatus of the above-described embodiment And a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like.

  As described above, the exposure apparatus of the present invention is suitable for a lithography process for manufacturing semiconductor elements, liquid crystal display elements, and the like.

Claims (28)

An exposure apparatus that irradiates exposure light onto the surface of an object via a projection optical system,
A stage capable of holding the object and moving in a two-dimensional plane perpendicular to the optical axis of the projection optical system;
A plurality of measurement points arranged in at least a part of the periphery of the predetermined area irradiated with the exposure light via the projection optical system, and each of the plurality of measurement points relates to an optical axis of the projection optical system; A first measuring device for measuring surface position information of the object;
A calculation device that calculates surface shape information of the object based on a measurement result of the first measurement device;
A second measuring device for measuring position information of the stage;
An exposure apparatus comprising: a control device that controls a surface position of the object with respect to the predetermined region based on a calculation result of the calculation device and a measurement result of the second measurement device. The exposure apparatus according to claim 1,
The calculation device includes:
In accordance with movement of the stage, based on surface position information at a predetermined point on the object measured at different measurement points, a surface position at that point in the surface shape information of the object is calculated. Exposure equipment. The exposure apparatus according to claim 2, wherein
The calculation device includes:
An exposure characterized in that a weighted average value based on the reliability of the measurement result of the first measuring device at a predetermined point on the object is calculated as a surface position at that point in the surface shape information of the object. apparatus. In the exposure apparatus according to claim 3,
The calculation device includes:
An exposure apparatus, wherein the weight of the measurement result of the first measurement apparatus is changed according to the time required for the measurement. In the exposure apparatus according to claim 3,
The calculation device includes:
An exposure apparatus, wherein the weight of the measurement result of the first measurement apparatus is changed according to the moving acceleration of the stage at the time of the measurement. The exposure apparatus according to claim 1,
The first measuring device includes:
When a predetermined point of the object is located at at least one of the plurality of measurement points, surface position information of the object is measured at the at least one measurement point. An exposure apparatus. The exposure apparatus according to claim 6, wherein
The first measuring device includes:
An exposure apparatus that measures surface position information of an object when detecting position information of an alignment mark for the object formed on the object. The exposure apparatus according to claim 1,
Obtained from a plurality of measurement results including the surface position information of a predetermined point on the object measured at a predetermined measurement point of the plurality of measurement points and the measurement results at that point at other measurement points. An exposure apparatus, further comprising a calibration device that calculates calibration information at the predetermined measurement point based on a difference from the surface position information to be obtained. The exposure apparatus according to claim 8, wherein
The calibration device comprises:
The exposure is characterized in that the calibration information is calculated in consideration of the reliability of the measurement result when the surface position of the predetermined point of the object is measured at the predetermined measurement point by the first measurement device. apparatus. The exposure apparatus according to claim 1,
The plurality of measurement points are:
An exposure apparatus comprising measurement points arranged to triple surround the predetermined area. The exposure apparatus according to claim 10, wherein
The plurality of measurement points include a first frame-like region surrounding the outside of the predetermined region, a second frame-like region surrounding the outside of the first frame-like region, and the outside of the second frame-like region And a third frame-like region surrounding each,
In any direction within the two-dimensional plane with respect to the predetermined area,
The size of the second frame-shaped region in the direction is not less than the size of the predetermined region in the direction;
When a part of the second frame-shaped region and the predetermined region are overlapped, at least three measurement points that are not on the same straight line included in the first frame-shaped region and the third frame-shaped region However, the exposure apparatus is characterized in that the plurality of measurement points are arranged so as to overlap with the measurement points of the first frame-like region. The exposure apparatus according to claim 11, wherein
The first measuring device includes:
The surface position information of the object is simultaneously measured at the at least three measurement points and at least one measurement point of the second frame-shaped region,
The calculation device includes:
Based on the measurement result of the first measurement device, calculate surface shape information of a partial region of the object,
The controller is
Measurements corresponding to the at least three measurement points of the measurement points of the first frame-shaped region when a partial region of the object approaches the first frame-shaped region due to the movement of the stage. An exposure apparatus that controls a surface position of the object based on a measurement result at a point and surface shape information of a partial region of the object. The exposure apparatus according to claim 10, wherein
Each of the frame regions is
The exposure is characterized in that the intervals between adjacent frame regions are the same, and the distance between the center of the predetermined region and the first frame region is an integral multiple of the interval. apparatus. The exposure apparatus according to claim 13, wherein
The calculation device includes:
Among the measurement results at the at least four measurement points before the movement of the stage and the measurement results at the at least four measurement points after the movement of the stage, at least 3 that are not on the same straight line on the object When the surface position information at one point is included, the surface shape information of the object is calculated by connecting the two measurement results on the basis of the surface position information of the at least three points. An exposure apparatus. The exposure apparatus according to claim 1,
The plurality of measurement points include measurement points arranged so as to double surround the predetermined area,
The calculation device includes:
An exposure apparatus that calculates surface shape information of the object based on a measurement result of the first measurement device and tilt information of the stage with respect to the two-dimensional surface measured by the second measurement device. . The exposure apparatus according to claim 15, wherein
The plurality of measurement points are respectively arranged in a first frame-shaped region surrounding the outside of the predetermined region and a second frame-shaped region surrounding the outside of the first frame-shaped region,
In any direction within the two-dimensional plane with respect to the predetermined area,
The size of the first frame-shaped region in the direction is equal to or larger than the size of the predetermined region in the direction;
When the first frame-like region and the predetermined region are overlapped, the at least one measurement point in the second frame-like region overlaps with the measurement point of the first frame-like region. An exposure apparatus comprising a plurality of measurement points. The exposure apparatus according to claim 16, wherein
The first measuring device includes:
The surface position information of the object is simultaneously measured at at least one measurement point of the third frame-shaped region and at least one measurement point of the first frame-shaped region,
The calculation device includes:
Based on the measurement result of the first measurement device, calculate surface shape information of a partial region of the object,
The controller is
Measurements corresponding to the at least one measurement point among the measurement points of the first frame-shaped region when a partial region of the object approaches the first frame-shaped region due to the movement of the stage. An exposure apparatus that controls a surface position of the object based on a measurement result at a point and surface shape information of a partial region of the object. The exposure apparatus according to claim 15, wherein
The distance from the center of the predetermined region to the first frame-like region is arranged so as to be an integral multiple of the interval between the first frame-like region and the second frame-like region. An exposure apparatus. The exposure apparatus according to claim 18, wherein
The calculation device includes:
Surface position information at at least one point on the object is included in the measurement results at the plurality of measurement points before the movement of the stage and the measurement results at the plurality of measurement points after the movement of the stage. In the exposure apparatus, the surface shape information of the object is calculated by connecting two measurement results based on the surface position information of the at least one point. The exposure apparatus according to claim 1,
The plurality of measurement points are:
Two rows of first measurement point rows along a first direction parallel to the moving direction of the stage when the exposure light is irradiated onto the object, and a second direction perpendicular to the first direction It is arranged so as to substantially surround the predetermined area with two rows of second measurement point rows,
The calculation device includes:
Calculating surface shape information of the object based on surface position information of the object in the second measurement point sequence;
The controller is
When the region corresponding to the surface shape information approaches the predetermined region due to the movement of the stage, the surface shape information and the position of the first measurement point sequence having the same position in the first direction as the center of the predetermined region An exposure apparatus that controls the surface position of the object based on surface position information at a measurement point. The exposure apparatus according to claim 20, wherein
Regarding the second direction,
The difference between the distance from the center of the predetermined region to the measurement point at the end of the first measurement point sequence and the distance from the center of the predetermined region to the second measurement point sequence is the same as the length of the predetermined region. An exposure apparatus characterized by comprising: The exposure apparatus according to claim 1,
A detector for detecting surface shape information of the object;
The plurality of measurement points are arranged so as to surround the predetermined region in a single layer,
The controller is
The exposure apparatus according to claim 1, wherein the surface position of the object with respect to the predetermined area is controlled based on a calculation result of the calculation apparatus and a detection result of the detection apparatus. The exposure apparatus according to claim 1,
The plurality of measurement points are:
An exposure apparatus comprising measurement points arranged on two opposite sides of four sides of a rectangle including the predetermined area. The exposure apparatus according to claim 23, wherein
The two opposite sides are
An exposure apparatus, wherein the exposure apparatus is a side arranged in the traveling direction of the object when the exposure light is irradiated as viewed from the predetermined area. The exposure apparatus according to claim 23, wherein
The plurality of measurement points are:
An exposure apparatus, wherein the exposure apparatus is a side arranged in a direction orthogonal to a traveling direction of the object when the exposure light is irradiated as viewed from the predetermined area. The exposure apparatus according to claim 23, wherein
The plurality of measurement points are:
An exposure apparatus, wherein the exposure apparatus is arranged on three sides of the four sides of the rectangle. The exposure apparatus according to claim 1,
The plurality of measurement points are:
An exposure apparatus comprising measurement points arranged in a plurality of rows arranged in one direction and in parallel as viewed from the predetermined region. The exposure apparatus according to claim 27, wherein
A detection system for detecting a mark for alignment of the object formed on the object;
The exposure apparatus, wherein the plurality of measurement point rows are arranged between the predetermined region and a detection visual field of the detection system.

Images