Measurement device, mark position measurement method, substrate processing system, and exposure method

Abstract

To enable accurate exposure of a plurality of partitioned regions on a substrate without causing a decrease in throughput in exposure processing of the substrate.SOLUTION: A lithography system 1000 comprises: a measuring device 100 that acquires position information of a plurality of marks on a substrate held on a first stage; and an exposure device 200 that mounts, on a second stage, the substrate for which acquisition of the position information of the marks has been completed, and performs an exposure operation of exposing the plurality of partitioned regions on the substrate with an energy beam. The exposure device performs the exposure operation on the basis of shape information of each of the plurality of partitioned regions calculated using the position information acquired by the measuring device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a substrate processing system, a substrate processing method, and a device manufacturing method, and particularly to a substrate processing system and a substrate processing method for processing a substrate on which a partitioned region is formed together with at least one mark, and a device manufacturing method using the substrate processing system.

Background Art

[0002] In a lithography process for manufacturing semiconductor elements or the like, a multilayer circuit pattern is formed by overlapping on a substrate such as a wafer or a glass plate (hereinafter generally referred to as a wafer). However, if the overlay accuracy between layers is poor, the semiconductor elements or the like cannot exhibit predetermined circuit characteristics and may become defective products in some cases. For this reason, usually, marks (alignment marks) are formed in advance in each of a plurality of shot regions on the wafer, and the position (coordinate value) of the mark in the stage coordinate system of the exposure apparatus is detected. Thereafter, wafer alignment is performed to align one shot region on the wafer with the pattern based on the mark position information and the known position information of the newly formed pattern (for example, a reticle pattern).

[0003] As a method of wafer alignment, from the balance with throughput, enhanced global alignment (EGA) that detects alignment marks only in some shot regions (also called sample shot regions or alignment shot regions) on the wafer and calculates the arrangement of shot regions on the wafer by a statistical method has become mainstream.

[0004] However, in the lithography process, when performing overlay exposure on a wafer, the wafer that has undergone process steps such as resist coating, development, etching, CVD (Chemical Vapor Deposition), and CMP (Chemical Mechanical Polishing) may have distortion in the arrangement of the shot regions of the previous layer due to the process, and this distortion can be a factor in reducing the overlay accuracy. In view of this, recent exposure apparatuses have a grid correction function and the like that correct not only the primary components of the wafer but also non-linear components of the shot array caused by the process (see, for example, Patent Document 1).

[0005] However, as the miniaturization of integrated circuits progresses, the requirements for overlay accuracy are becoming increasingly strict. In order to perform more accurate correction, it is essential to increase the number of sample shot regions, that is, to increase the number of marks to be detected. Also, in a twin-stage type exposure apparatus equipped with two stages on which the wafer is placed, while exposure of the wafer is being performed on one stage, detection of marks on the wafer and the like can be executed on the other stage. Therefore, it is possible to increase the number of sample shot regions without significantly reducing the throughput.

[0006] However, the current requirements for overlay accuracy have become even more strict, and even in the case of a twin-stage type exposure apparatus, it has become difficult to detect a sufficient number of marks to achieve the required overlay accuracy without reducing the throughput.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Means for Solving the Problems

[0008] According to a first aspect, there is provided a substrate processing system for processing a substrate on which a plurality of partition regions are formed together with a plurality of marks, the system including: a first stage capable of holding the substrate; a measuring device configured to acquire position information of the plurality of marks on the substrate held on the first stage; a second stage on which the substrate is placed after the acquisition of the position information of the plurality of marks by the measuring device is completed; and an exposure device configured to perform an exposure operation of exposing the plurality of partition regions on the substrate placed on the second stage with an energy beam. The exposure device performs the exposure operation based on shape information of each of the plurality of partition regions calculated using the position information acquired by the measuring device.

[0009] According to a second aspect, there is provided a substrate processing method for processing a substrate on which a plurality of partition regions are formed together with a plurality of marks, the method including: acquiring position information of the plurality of marks on the substrate held on a first stage capable of holding the substrate; transferring the substrate, after the acquisition of the position information of the plurality of marks is completed, to a second stage different from the first stage; and performing an exposure operation of exposing the plurality of partition regions on the substrate placed on the second stage with an energy beam. The exposure operation is performed based on shape information of each of the plurality of partition regions calculated using the position information.

[0010] According to a third aspect, there is provided a device manufacturing method including: exposing a substrate using the substrate processing system according to the first aspect; and developing the exposed substrate.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, one embodiment will be described with reference to FIGS. 1 to 10. FIG. 1 schematically shows the configuration of a lithography system (substrate processing system) 1000 according to one embodiment.

[0013] As shown in FIG. 1, a lithography system 1000 includes a measurement device 100, an exposure device 200, and a substrate processing device 300 that are connected in-line with each other. Here, since a coater / developer (C / D) is used as the substrate processing device 300, it will be hereinafter referred to as C / D 300 as appropriate. The lithography system 1000 is installed in a clean room. Note that being connected in-line means that different devices are connected in a state where the transfer paths of wafers (substrates) are connected. In this specification, the terms "connected in-line" or "in-line connection" are used in this sense.

[0014] In a normal lithography system, for example, as disclosed in U.S. Patent No. 6,698,944, an in-line interface unit having a wafer transfer system for connecting an exposure device and a substrate processing device (C / D) in-line with each other inside a chamber is arranged. On the other hand, as can be seen from FIG. 1, in the lithography system 1000 according to the present embodiment, instead of the in-line interface unit, the measurement device 100 is arranged between the exposure device 200 and the C / D 300.

[0015] The exposure device 200, the C / D 300, and the measurement device 100 included in the lithography system 1000 all have chambers, and the chambers are arranged adjacent to each other. An exposure control device 220 included in the exposure device 200, a coating / development control device 320 included in the C / D 300, and a control device 60 included in the measurement device 100 are connected to each other via a local area network (LAN) 500 and communicate with each other among the three. A storage device 400 is also connected to the LAN 500.

[0016] First, the measuring device 100 will be described. In FIG. 2, the configuration of the measuring device 100 is schematically shown in a perspective view. Note that the measuring device 100 shown in FIG. 2 is actually composed of a chamber and components housed inside the chamber, but in the following, the description of the chamber will be omitted. In the measuring device 100 according to the present embodiment, a mark detection system MDS is provided as will be described later. In the following, the direction of the optical axis AX1 of the mark detection system MDS is defined as the Z-axis direction, and within the plane orthogonal to this, the direction in which the movable stage described later moves with a long stroke is defined as the Y-axis direction, the direction orthogonal to the Z-axis and the Y-axis is defined as the X-axis direction, and the rotation (tilt) directions around the X-axis, Y-axis, and Z-axis are defined as the θx, θy, and θz directions, respectively, for the description. Here, the mark detection system MDS has an L-shaped outer shape in a side view (for example, viewed from the +X direction), and a cylindrical lens barrel portion 41 is provided at its lower end (tip). Inside the lens barrel portion 41, an optical system (refractive optical system) composed of a plurality of lens elements having a common optical axis AX1 in the Z-axis direction is housed. In this specification, for convenience of explanation, the optical axis AX1 of the refractive optical system inside the lens barrel portion 41 is referred to as the optical axis AX1 of the mark detection system MDS.

[0017] FIG. 3(A) shows a partial omission of the front view of the measuring device 100 in FIG. 2 (viewed from the -Y direction), and FIG. 3(B) shows a partial omission of the cross-sectional view of the measuring device 100 taken along the XZ plane passing through the optical axis AX1. Also, FIG. 4 shows a partial omission of the cross-sectional view of the measuring device 100 taken along the YZ plane passing through the optical axis AX1.

[0018] As shown in Fig. 2, the measuring device 100 includes a surface plate 12 having an upper surface substantially parallel to the XY plane orthogonal to the optical axis AX1, a wafer slider (hereinafter abbreviated as slider) 10 disposed on the surface plate 12, holding the wafer W and movable in the X-axis and Y-axis directions with a predetermined stroke with respect to the surface plate 12, and capable of fine movement (fine displacement) in the Z-axis, θx, θy, and θz directions, a drive system 20 for driving the slider 10 (not shown in Fig. 2, see Fig. 7), a first position measurement system 30 for measuring the position information of the slider 10 in each direction of the X-axis, Y-axis, Z-axis, θx, θy, and θz with respect to the surface plate 12 (hereinafter referred to as six-degree-of-freedom directions) (not shown in Fig. 2, see Figs. 4 and 7), a measurement unit 40 having a mark detection system MDS for detecting marks on the wafer W mounted (held) on the slider 10, a second position measurement system 50 for measuring the relative position information between the mark detection system MDS (measurement unit 40) and the surface plate 12 (not shown in Fig. 2, see Fig. 7), and a control device 60 for obtaining the measurement information by the first position measurement system 30 and the measurement information by the second position measurement system 50 while controlling the driving of the slider 10 by the drive system 20, and obtaining the position information of a plurality of marks on the wafer W held by the slider 10 using the mark detection system MDS (not shown in Fig. 2, see Fig. 7).

[0019] The surface plate 12 is formed of a rectangular parallelepiped member having a rectangular (or square) shape in plan view, and its upper surface is finished to have a very high flatness, forming a guide surface when the slider 10 moves. As the material of the surface plate 12, a material having a low coefficient of thermal expansion, also called a zero-expansion material, such as an Invar-type alloy, an ultra-low expansion cast steel, or an ultra-low expansion glass ceramic, is used.

[0020] On the surface plate 12, notch-shaped cavities 12a with openings at the bottom are formed at a total of three locations: one at the center in the X-axis direction on the -Y side surface, and one at each of the both ends in the X-axis direction on the +Y side surface. In FIG. 2, among the three cavities 12a, the cavity 12a formed on the -Y side surface is shown. Inside each cavity 12a, a vibration damping device 14 is arranged. The surface plate 12 is three-point supported by three vibration damping devices 14 on the upper surface parallel to the XY plane of a rectangular base frame 16 installed on the floor F so that the upper surface is substantially parallel to the XY plane. Note that the number of the vibration damping devices 14 is not limited to three.

[0021] As shown in FIG. 4, the slider 10 has a total of four air static pressure bearings (air bearings) 18, one at each of the four corners of the bottom surface, and each bearing surface is attached in a state where it is substantially flush with the lower surface of the slider 10. The slider 10 is levitated and supported on the upper surface of the surface plate 12 with a predetermined clearance (gap), for example, a clearance of about several μm, by the static pressure (pressure within the gap) between the bearing surface of the pressurized air jetted from these four air bearings 18 toward the surface plate 12 and the upper surface (guide surface) of the surface plate 12. In this embodiment, the slider 10 is made of a zero-expansion glass (for example, Zero-Dura of Shot Co., Ltd.), which is a type of zero-expansion material.

[0022] On the upper part of the slider 10, a recess 10a with a circular shape in plan view and a predetermined depth, whose inner diameter is slightly larger than the diameter of the wafer W, is formed, and a wafer holder WH with a diameter approximately the same as that of the wafer W is disposed inside the recess 10a. As the wafer holder WH, a vacuum chuck, an electrostatic chuck, a mechanical chuck, or the like can be used. As an example, a pinch chuck type vacuum chuck is used. The wafer W is adsorbed and held by the wafer holder WH in a state where its upper surface is substantially flush with the upper surface of the slider 10. A plurality of suction ports are formed in the wafer holder WH, and the plurality of suction ports are connected to a vacuum pump 11 (see FIG. 7) via a vacuum piping system (not shown). Then, the on / off operation of the vacuum pump 11 is controlled by the control device 60. Note that either one or both of the slider 10 and the wafer holder WH may be referred to as the "first substrate holding member".

[0023] Further, the slider 10 is provided with a vertically moving member (not shown) that moves up and down through, for example, three circular openings formed in the wafer holder WH, and cooperates with the wafer transfer system 70 (not shown in FIG. 2, see FIG. 7) to load the wafer onto the wafer holder WH and unload the wafer from the wafer holder WH. A driving device 13 for driving the vertically moving member is controlled by the control device 60 (see FIG. 7).

[0024] In this embodiment, as an example, a wafer holder WH having a size capable of adsorbing and holding a 300 mm wafer with a diameter of 300 mm is used. Note that when the wafer transfer system 70 has a non-contact holding member, such as a Bernoulli chuck, that sucks and holds the wafer on the wafer holder WH in a non-contact manner from above, it is not necessary to provide a vertically moving member on the slider 10, nor is it necessary to form a circular opening for the vertically moving member in the wafer holder WH.

[0025] As shown in FIGS. 3(B) and 4, a two-dimensional grating (hereinafter simply referred to as a grating) RG1 is horizontally arranged (parallel to the surface of the wafer W) in a region on the lower surface of the slider 10 that is slightly larger than the wafer W. The grating RG1 includes a reflective diffraction grating (X diffraction grating) having the X-axis direction as the periodic direction and a reflective diffraction grating (Y diffraction grating) having the Y-axis direction as the periodic direction. The pitch of the grating lines of the X diffraction grating and the Y diffraction grating is set to, for example, 1 μm.

[0026] The vibration isolation device 14 is an active vibration isolation system (so-called AVIS (Active Vibration Isolation System)), and includes an accelerometer, a displacement sensor (such as a capacitance sensor), an actuator (such as a voice coil motor), and an air mount that functions as an air damper. The vibration isolation device 14 can attenuate relatively high-frequency vibrations by the air mount (air damper) and can perform vibration isolation (vibration control) by the actuator. Therefore, the vibration isolation device 14 can avoid the transmission of vibrations between the surface plate 12 and the base frame 16. Note that a hydraulic damper may be used instead of the air mount (air damper).

[0027] Here, an actuator is provided in addition to the air mount because the internal pressure of the gas in the gas chamber of the air mount is high, so the control response can only be ensured up to about 20 Hz. Therefore, when high-response control is required, it is necessary to control the actuator according to the output of an accelerometer (not shown). However, minute vibrations such as floor vibrations are isolated by the air mount.

[0028] The upper end surface of the vibration isolation device 14 is connected to the surface plate 12. Gas (e.g., compressed air) can be supplied to the air mount via a gas supply port (not shown), and the air mount expands and contracts in the Z-axis direction with a predetermined stroke (e.g., about 1 mm) according to the amount of gas filled inside (pressure change of compressed air). Therefore, by individually moving up and down three locations on the surface plate 12 from below using the air mounts of each of the three vibration isolation devices 14, the surface plate 12 and the slider 10 floatingly supported thereon can have their positions in the Z-axis direction, θx direction, and θy direction adjusted arbitrarily. Further, the actuator of the vibration isolation device 14 can drive the surface plate 12 not only in the Z-axis direction but also in the X-axis direction and the Y-axis direction. Note that the driving amounts in the X-axis direction and the Y-axis direction are smaller than the driving amount in the Z-axis direction. The three vibration isolation devices 14 are connected to a control device 60 (see FIG. 7). Note that each of the three vibration isolation devices 14 may be provided with an actuator that can move the surface plate 12 not only in the X-axis direction, Y-axis direction, and Z-axis direction but also, for example, in six degrees of freedom directions. The control device 60 always controls the actuators of the three vibration isolation devices 14 in real time so that the position of the surface plate 12 in the six degrees of freedom directions, where the head portion 32 of the first position measurement system 30 described later is fixed, maintains a desired positional relationship with respect to the mark detection system MDS (measurement unit 40) measured by the second position measurement system 50. Note that each of the three vibration isolation devices 14 may be subjected to feed-forward control. For example, the control device 60 may perform feed-forward control on each of the three vibration isolation devices 14 based on the measurement information of the first position measurement system 30. Note that the control of the vibration isolation device 14 by the control device 60 will be described in further detail later.

[0029] As shown in FIG. 7, the drive system 20 includes a first drive device 20A that drives the slider 10 in the X-axis direction and a second drive device 20B that drives the slider 10 in the Y-axis direction integrally with the first drive device 20A.

[0030] As can be seen from FIGS. 2 and 4, on the side surface of the slider 10 on the -Y side, there is a pair of rotors 22a formed of a magnet unit (or a coil unit), which are L-shaped in reverse in side view, and are fixed at a predetermined interval in the X-axis direction. On the side surface of the slider 10 on the +Y side, as shown in FIG. 4, there is a pair of rotors 22b (however, the rotor 22b on the +X side is not shown) formed of a magnet unit (or a coil unit), which are fixed at a predetermined interval in the X-axis direction. The pair of rotors 22a and the pair of rotors 22b are arranged symmetrically left and right, but are configured in the same manner as each other.

[0031] As shown in FIGS. 2 to 4, the rotors 22a and 22b are arranged at a predetermined distance apart in the Y-axis direction, which forms a part of the movable stage 24 in the shape of a rectangular frame in plan view, and are supported in a non-contact manner on the upper surfaces substantially parallel to the XY plane of a pair of plate members 24a and 24b extending in the X-axis direction. That is, air bearings (not shown) are respectively provided on the lower surfaces (the surfaces facing the plate members 24a and 24b) of the rotors 22a and 22b, and the rotors 22a and 22b are supported in a non-contact manner from below by the movable stage 24 by the levitation force (static pressure of pressurized air) generated by these air bearings against the plate members 24a and 24b. Incidentally, the self-weight of the slider 10 to which each pair of rotors 22a and 22b is fixed is supported by the levitation force generated by the four air bearings 18 against the surface plate 12, as described above.

[0032] On the upper surfaces of each of the pair of plate members 24a and 24b, as shown in FIGS. 2 to 4, stators 26a and 26b formed of a coil unit (or a magnet unit) are arranged in a region excluding both end portions in the X-axis direction.

[0033] Due to the electromagnetic interaction between a pair of movers 22a and a stator 26a, a driving force (electromagnetic force) for driving the pair of movers 22a in the X-axis direction and a driving force (electromagnetic force) for driving the pair of movers 22a in the Y-axis direction are generated. Due to the electromagnetic interaction between a pair of movers 22b and a stator 26b, a driving force (electromagnetic force) for driving the pair of movers 22b in the X-axis direction and a driving force (electromagnetic force) for driving the pair of movers 22b in the Y-axis direction are generated. That is, an XY linear motor 28A that generates driving forces in the X-axis direction and the Y-axis direction is constituted by the pair of movers 22a and the stator 26a, and an XY linear motor 28B that generates driving forces in the X-axis direction and the Y-axis direction is constituted by the pair of movers 22b and the stator 26b. The XY linear motor 28A and the XY linear motor 28B constitute a first driving device 20A that drives the slider 10 with a predetermined stroke in the X-axis direction and drives it slightly in the Y-axis direction (see FIG. 7). The first driving device 20A can drive the slider 10 in the θz direction by making the magnitudes of the driving forces in the X-axis direction generated by the XY linear motor 28A and the XY linear motor 28B different from each other. The first driving device 20A is controlled by a control device 60 (see FIG. 7). In the present embodiment, since the first driving device 20A and a second driving device, which will be described later, constitute a coarse and fine driving system for driving the slider 10 in the Y-axis direction, the first driving device 20A generates not only a driving force in the X-axis direction but also a driving force in the Y-axis direction. However, the first driving device 20A does not necessarily have to generate a driving force in the Y-axis direction.

[0034] The movable stage 24 has a pair of plate members 24a and 24b, and a pair of connecting members 24c and 24d that are arranged at a predetermined distance from each other in the X-axis direction and extend in the Y-axis direction respectively. Step portions are formed at both ends in the Y-axis direction of the connecting members 24c and 24d. And with one end and the other end in the longitudinal direction of the plate member 24a placed on the -Y side step portions of the connecting members 24c and 24d respectively, the connecting members 24c and 24d and the plate member 24a are integrated. Also, with one end and the other end in the longitudinal direction of the plate member 24b placed on the +Y side step portions of the connecting members 24c and 24d respectively, the connecting members 24c and 24d and the plate member 24b are integrated (see Fig. 3(B)). That is, in this way, the pair of plate members 24a and 24b are connected by the pair of connecting members 24c and 24d, and the rectangular frame-shaped movable stage 24 is formed.

[0035] As shown in Figs. 2 and 3(A), a pair of linear guides 27a and 27b extending in the Y-axis direction are fixed near both ends in the X-axis direction on the upper surface of the base frame 16. Inside one of the linear guides 27a located on the +X side, a stator 25a of a Y-axis linear motor 29A (see Fig. 3(B)) composed of a coil unit (or magnet unit) extending almost the entire length in the Y-axis direction is housed near the upper surface and the -X side surface. Opposite to the upper surface and the -X side surface of the linear guide 27a, a mover 23a that forms a Y-axis linear motor 29A together with the stator 25a and is composed of a magnet unit (or coil unit) with an L-shaped cross section is arranged. Air bearings that eject pressurized air against the opposing surfaces are fixed to the lower surface and the +X side surface of the mover 23a that are respectively opposite to the upper surface and the -X side surface of the linear guide 27a. Among them, in particular, a vacuum preload type air bearing is used as the air bearing fixed to the +X side surface of the mover 23a. This vacuum preload type air bearing maintains a constant value for the clearance (gap) in the X-axis direction between the mover 23a and the linear guide 27a by the balance between the static pressure of the pressurized air and the vacuum preload force between the bearing surface and the -X side surface of the linear guide 27a.

[0036] On the upper surface of the mover 23a, a plurality of, for example, two rectangular parallelepiped members, an X guide 19, are fixed at a predetermined interval in the Y-axis direction. To each of the two X guides 19, a slide member 21 having an inverted U-shaped cross-section that forms a uniaxial guide device together with the X guide 19 is engaged in a non-contact manner. Air bearings are respectively provided on three surfaces of the slide member 21 facing the X guide 19.

[0037] As shown in FIG. 2, the two slide members 21 are respectively fixed to the lower surface (-Z side surface) of the connecting member 24c.

[0038] The other linear guide 27b located on the -X side houses the stator 25b of the Y-axis linear motor 29B composed of a coil unit (or a magnet unit) inside, and is symmetric, but is configured in the same manner as the linear guide 27a (see FIG. 3(B)). Opposite to the upper surface and the +X side surface of the linear guide 27b, there is a mover 23b composed of a magnet unit (or a coil unit) having an L-shaped cross-section similar to that of the mover 23a, which is symmetric, and together with the stator 25b, constitutes the Y-axis linear motor 29B. Air bearings are respectively fixed to the lower surface and the -X side surface of the mover 23b facing the upper surface and the +X side surface of the linear guide 27b. In particular, as the air bearing fixed to the -X side surface of the mover 23b, a vacuum preloading type air bearing is used. By this vacuum preloading type air bearing, the clearance (gap) in the X-axis direction between the mover 23b and the linear guide 27b is maintained at a constant value.

[0039] Between the upper surface of the mover 23b and the bottom surface of the connecting member 24d, two uniaxial guide devices composed of an X guide 19 and a slide member 21 that engages with the X guide 19 in a non-contact manner are provided as described above.

[0040] The movable stage 24 is supported from below by the movers 23a and 23b via two (a total of four) uniaxial guide devices on each of the +X side and -X side, and is movable in the X-axis direction on the movers 23a and 23b. Therefore, when the slider 10 is driven in the X-axis direction by the first drive device 20A described above, the reaction force of the driving force acts on the movable stage 24 provided with the stators 26a and 26b, and the movable stage 24 moves in the direction opposite to the slider 10 in accordance with the law of conservation of momentum. That is, the generation of vibration caused by the reaction force of the driving force in the X-axis direction with respect to the slider 10 is prevented (or effectively suppressed) by the movement of the movable stage 24. That is, the movable stage 24 functions as a counter mass when the slider 10 moves in the X-axis direction. However, it is not always necessary to make the movable stage 24 function as a counter mass. Note that the slider 10 is not particularly provided because it only moves slightly in the Y-axis direction with respect to the movable stage 24, but a counter mass may be provided to prevent (or effectively suppress) the generation of vibration caused by the driving force for driving the slider 10 in the Y-axis direction with respect to the movable stage 24.

[0041] The Y-axis linear motor 29A generates a driving force (electromagnetic force) for driving the mover 23a in the Y-axis direction by the electromagnetic interaction between the mover 23a and the stator 25a, and the Y-axis linear motor 29B generates a driving force (electromagnetic force) for driving the mover 23b in the Y-axis direction by the electromagnetic interaction between the mover 23b and the stator 25b.

[0042] The driving forces in the Y-axis direction generated by the Y-axis linear motors 29A and 29B act on the movable stage 24 via two uniaxial guide devices on each of the +X side and -X side. Thereby, the slider 10 is driven in the Y-axis direction integrally with the movable stage 24. That is, in the present embodiment, the second drive device 20B (see FIG. 7) for driving the slider 10 in the Y-axis direction is configured by the movable stage 24, the four uniaxial guide devices, and the pair of Y-axis linear motors 29A and 29B.

[0043] In this embodiment, the pair of Y-axis linear motors 29A and 29B are physically separated from the surface plate 12 and are also vibrationally separated by the three vibration isolation devices 14. Note that the linear guides 27a and 27b provided with the stators 25a and 25b of the pair of Y-axis linear motors 29A and 29B may be configured to be movable in the Y-axis direction with respect to the base frame 16 and function as a counter mass during driving of the slider 10 in the Y-axis direction.

[0044] As shown in FIG. 2, the measurement unit 40 includes a unit main body 42 in which a notch-shaped cavity 42a with an open bottom is formed on the -Y side surface, the above-described mark detection system MDS connected to the unit main body 42 with its base end portion inserted into the cavity 42a, and a connection mechanism 43 that connects the lens barrel portion 41 at the tip of the mark detection system MDS to the unit main body 42.

[0045] The connection mechanism 43 includes a support plate 44 that supports the lens barrel portion 41 on the back side (+Y side) via a mounting member (not shown), and a pair of support arms 45a and 45b that support the support plate 44 at one end portion each and have the other end portions fixed to the bottom surface of the unit main body 42.

[0046] In this embodiment, corresponding to the fact that a sensitizer (resist) is applied to the upper surface of the wafer held on the slider 10, as the mark detection system MDS, one that uses a detection beam having a wavelength that does not expose the resist is used. As the mark detection system MDS, for example, a broadband detection light beam that does not expose the resist applied on the wafer is irradiated onto the target mark, and an image of the target mark formed on the light receiving surface by the reflected light from the target mark and an image of an index (index pattern on an index plate provided inside) (not shown) are imaged using an imaging device (such as a CCD), and an FIA (Field Image Alignment) system of an image processing method that outputs their imaging signals is used. The imaging signal from the mark detection system MDS is supplied to the control device 60 via a signal processing device 49 (not shown in FIG. 2, see FIG. 7) (see FIG. 7). The mark detection system MDS has an alignment autofocus function for adjusting the focal position of the optical system.

[0047] Between the lens barrel portion 41 and the support plate 44, as shown in FIG. 2, a head attachment member 51 having a substantially isosceles triangular shape is disposed. An opening penetrating in the Y-axis direction of FIG. 2 is formed in the head attachment member 51, and the lens barrel portion 41 is attached (fixed) to the support plate 44 via an attachment member (not shown) inserted into this opening. Also, the back surface of the head attachment member 51 is fixed to the support plate 44. In this way, the lens barrel portion 41 (mark detection system MDS), the head attachment member 51, and the support plate 44 are integrated with the unit main body 42 via a pair of support arms 45a and 45b.

[0048] Inside the unit main body 42, there are arranged the aforementioned signal processing device 49 and the like that processes the imaging signal output as a detection signal from the mark detection system MDS, calculates the position information of the target mark with respect to the detection center, and outputs it to the control device 60. The unit main body 42 is supported from below at three points via a plurality of, for example, three vibration isolation devices 48 on a portal-shaped support frame 46 when viewed from the -Y side installed on the base frame 16. Each vibration isolation device 48 is an active vibration isolation system (so-called AVIS (Active Vibration Isolation System)), and includes an accelerometer, a displacement sensor (for example, a capacitance sensor, etc.), and an actuator (for example, a voice coil motor, etc.), as well as a mechanical damper such as an air damper or a hydraulic damper. The vibration isolation device 48 can attenuate relatively high-frequency vibrations by the mechanical damper and can perform vibration isolation (vibration control) by the actuator. Therefore, each vibration isolation device 48 can avoid the transmission of relatively high-frequency vibrations between the support frame 46 and the unit main body 42.

[0049] Note that the mark detection system MDS is not limited to the FIA system. For example, instead of the FIA system, a diffraction light interference type alignment detection system that irradiates coherent detection light onto the target mark, interferes two diffraction lights (for example, diffraction lights of the same order or diffraction lights diffracted in the same direction) generated from the target mark, and outputs a detection signal may be used. Alternatively, a diffraction light interference type alignment system may be used together with the FIA system to simultaneously detect two target marks. Further, as the mark detection system MDS, a beam scan type alignment system that scans measurement light in a predetermined direction with respect to the target mark while moving the slider 10 in a predetermined direction may be used. In the present embodiment, the mark detection system MDS is assumed to have an alignment autofocus function. Instead of this, or in addition to this, the measurement unit 40 may be provided with a focus position detection system, for example, an oblique incidence type multi-point focus position detection system having the same configuration as that disclosed in U.S. Patent No. 5,448,332 etc.

[0050] As shown in FIGS. 3(B) and 4, the first position measurement system 30 is disposed in a recess formed on the upper surface of the surface plate 12 and has a head portion 32 fixed to the surface plate 12. The upper surface of the head portion 32 faces the lower surface (the surface on which the grating RG1 is formed) of the slider 10. A predetermined clearance (gap) of, for example, about several mm is formed between the upper surface of the head portion 32 and the lower surface of the slider 10.

[0051] As shown in FIG. 7, the first position measurement system 30 includes an encoder system 33 and a laser interferometer system 35. The encoder system 33 irradiates a plurality of beams from the head portion 32 to the measurement portion (the formation surface of the grating RG1) on the lower surface of the slider 10, and receives a plurality of return beams (for example, a plurality of diffracted beams from the grating RG1) from the measurement portion on the lower surface of the slider 10, and can acquire the position information of the slider 10. The encoder system 33 includes an X linear encoder 33x that measures the position of the slider 10 in the X-axis direction, and a pair of Y linear encoders 33ya and 33yb that measure the position of the slider 10 in the Y-axis direction. In the encoder system 33, a diffraction interference type head having the same configuration as an encoder head (hereinafter, appropriately abbreviated as a head) disclosed in, for example, U.S. Patent No. 7,238,931 and U.S. Patent Application Publication No. 2007 / 288,121 is used. The head includes a light source and a light receiving system (including a photodetector) and an optical system. In this embodiment, at least the optical system may be arranged inside the housing of the head portion 32 facing the grating RG1, and at least one of the light source and the light receiving system may be arranged outside the housing of the head portion 32.

[0052] FIG. 5(A) shows the head portion 32 in a perspective view, and FIG. 5(B) shows a plan view of the upper surface of the head portion 32 as viewed from the +Z direction. The encoder system 33 measures the position of the slider 10 in the X-axis direction with one X head 37x and measures the position of the slider 10 in the Y-axis direction with a pair of Y heads 37ya and 37yb (see FIG. 5(B)). That is, the aforementioned X linear encoder 33x is constituted by the X head 37x that measures the position of the slider 10 in the X-axis direction using the X diffraction grating of the grating RG1, and a pair of Y linear encoders 33ya and 33yb are constituted by a pair of Y heads 37ya and 37yb that measure the position of the slider 10 in the Y-axis direction using the Y diffraction grating of the grating RG1.

[0053] As shown in FIGS. 5(A) and 5(B), the X head 37x irradiates the same irradiation point on the grating RG1 with measurement beams LBx1 and LBx2 (shown by solid lines in FIG. 5(A)) from two points (see the white circles in FIG. 5(B)) that are equidistant from the straight line CL parallel to the Y axis passing through the center of the head portion 32 on a straight line LX parallel to the X axis passing through the center of the head portion 32. The irradiation points of the measurement beams LBx1 and LBx2, that is, the detection points of the X head 37x (see the reference symbol DP in FIG. 5(B)), coincide in position in the X-axis direction and the Y-axis direction with the detection center of the mark detection system MDS.

[0054] Here, the measurement beams LBx1 and LBx2 are those obtained by polarization separation of the beam from the light source by a polarization beam splitter (not shown). When the measurement beams LBx1 and LBx2 are irradiated on the grating RG1, the diffracted beams of a predetermined order, for example, the first-order diffracted beams (the first diffracted beams), of these measurement beams LBx1 and LBx2 by the X diffraction grating are respectively folded back by a reflection mirror via a lens and a quarter-wave plate (not shown), and the polarization direction is rotated by 90 degrees by passing through the quarter-wave plate twice, and then re-enters the polarization beam splitter through the original optical path and is coaxially combined. After that, the interference light between the first-order diffracted beams of the measurement beams LBx1 and LBx2 is received by a photodetector (not shown), thereby measuring the position of the slider 10 in the X-axis direction.

[0055] As shown in FIG. 5(B), each of the pair of Y heads 37ya and 37yb is arranged on the +X side and the -X side of the straight line CL. As shown in FIGS. 5(A) and 5(B), the Y head 37ya irradiates the common irradiation point on the grating RG1 with the measurement beams LBya1 and LBya2 (shown by broken lines in FIG. 5(A)) from two points (see the white circles in FIG. 5(B)) that are equidistant from the straight line LX on the straight line LYa. The irradiation points of the measurement beams LBya1 and LBya2, that is, the detection points of the Y head 37ya, are shown by the reference symbol DPya in FIG. 5(B).

[0056] The Y-head 37yb irradiates the measurement beams LByb1 and LByb2 from two points (see the white circles in Fig. 5(B)) that are symmetric with respect to the straight line CL to the injection points of the measurement beams LBya1 and LBya2 of the Y-head 37ya onto the common irradiation point DPyb on the grating RG1. As shown in Fig. 5(B), the detection points DPya and Dpyb of the Y-heads 37ya and 37yb are arranged on a straight line LX parallel to the X-axis.

[0057] The measurement beams LBya1 and LBya2 are also those in which the same beam is polarization-separated by a polarization beam splitter. The interference light between the diffraction beams of a predetermined order, for example, the first-order diffraction beams (second diffraction beams) of these measurement beams LBya1 and LBya2 by the Y diffraction grating is photoelectrically detected by a photodetector (not shown) in the same manner as described above, whereby the position of the slider 10 in the Y-axis direction is measured. Regarding the measurement beams LByb1 and LByb2, in the same manner as the measurement beams LBya1 and LBya2, the interference light between the first-order diffraction beams (second diffraction beams) is photoelectrically detected by a photodetector (not shown), whereby the position of the slider 10 in the Y-axis direction is measured.

[0058] Here, the control device 60 determines the position of the slider 10 in the Y-axis direction based on the average of the measured values of the two Y-heads 37ya and 37yb. Therefore, in the present embodiment, the position of the slider 10 in the Y-axis direction is measured with the midpoint DP of the detection points DPya and Dpyb as the substantial measurement point. The midpoint DP coincides with the irradiation point on the grating RG1 of the measurement beams LBx1 and LBX2.

[0059] That is, in this embodiment, regarding the measurement of the position information of the slider 10 in the X-axis direction and the Y-axis direction, a common detection point is provided, and the position of this detection point in the XY plane coincides with the detection center of the mark detection system MDS at the nm level, for example. Based on the relative position information between the mark detection system MDS (measurement unit 40) measured by the second position measurement system 50 and the surface plate 12, the actuators of the three vibration isolation devices 14 are always controlled in real time by the control device 60. Therefore, in this embodiment, the control device 60 can always measure the position information of the slider 10 in the XY plane directly below the detection center of the mark detection system MDS (on the back side of the slider 10) when measuring the alignment marks on the wafer W placed on the slider 10 by using the encoder system 33. In addition, the control device 60 measures the rotation amount of the slider 10 in the θz direction based on the difference between the measured values of the pair of Y heads 37ya and 37yb.

[0060] The laser interferometer 35 can obtain the position information of the slider 10 by irradiating a length measurement beam onto the measurement portion (the surface on which the grating RG1 is formed) on the lower surface of the slider 10 and receiving the return beam (for example, the reflected light from the surface on which the grating RG1 is formed). As shown in FIG. 5(A), the laser interferometer system 35 irradiates four length measurement beams LBz1, LBz2, LBz3, and LBz4 onto the lower surface of the slider 10 (the surface on which the grating RG1 is formed). The laser interferometer system 35 includes laser interferometers 35a to 35d (see FIG. 7) that irradiate each of these four length measurement beams LBz1, LBz2, LBz3, and LBz4. In this embodiment, four Z heads are configured by the laser interferometers 35a to 35d.

[0061] In the laser interferometer system 35, as shown in FIGS. 5(A) and 5(B), four length-measuring beams LBz1, LBz2, LBz3, and LBz4 are emitted parallel to the Z-axis from four points corresponding to the respective vertices of a square having two sides parallel to the X-axis and two sides parallel to the Y-axis, with the detection point DP as the center. In this case, the emission points (irradiation points) of the length-measuring beams LBz1 and LBz4 are equidistant from the straight line LX on the straight line LYa, and the emission points (irradiation points) of the remaining length-measuring beams LBz2 and LBz3 are equidistant from the straight line LX on the straight line LYb. In the present embodiment, the surface on which the grating RG1 is formed also serves as the reflection surface for each length-measuring beam from the laser interferometer system 35. The control device 60 measures information on the position of the slider 10 in the Z-axis direction and the rotation amounts in the θx direction and the θy direction using the laser interferometer system 35. As is clear from the above description, the slider 10 is not actively driven by the drive system 20 described above with respect to the surface plate 12 in the Z-axis, θx, and θy directions. However, since the slider 10 is levitated on the surface plate 12 by the four air bearings 18 arranged at the four corners of the bottom surface, in actuality, the position of the slider 10 changes on the surface plate 12 in the Z-axis, θx, and θy directions. That is, the slider 10 is actually movable with respect to the surface plate 12 in the Z-axis, θx, and θy directions. In particular, the displacements of the slider 10 in the θx and θy directions cause measurement errors (Abbe errors) in the encoder system 33. Considering this point, the first position measurement system 30 (laser interferometer system 35) measures the position information of the slider 10 in the Z-axis, θx, and θy directions.

[0062] Note that, for measuring the information on the position of the slider 10 in the Z-axis direction and the rotation amounts in the θx direction and the θy direction, it is sufficient to be able to make the beams incident on three different points on the surface on which the grating RG1 is formed. Therefore, three Z-heads, for example, laser interferometers, are sufficient. A protective glass for protecting the grating RG1 may be provided on the lower surface of the slider 10, and a wavelength selection filter that transmits each measurement beam from the encoder system 33 and blocks the transmission of each length-measuring beam from the laser interferometer system 35 may be provided on the surface of the protective glass.

[0063] As can be understood from the above description, the control device 60 can measure the position of the slider 10 in six degrees of freedom by using the encoder system 33 and the laser interferometer system 35 of the first position measurement system 30. In this case, in the encoder system 33, since the optical path lengths of the measurement beams in the air are extremely short and almost equal, the influence of air fluctuations can be almost ignored. Therefore, the encoder system 33 can measure the position information of the slider 10 in the XY plane (including the θz direction) with high accuracy. Further, the detection points on the substantial gratings RG1 in the X-axis direction and the Y-axis direction by the encoder system 33, and the detection point on the lower surface of the slider 10 in the Z-axis direction by the laser interferometer system 35 coincide with the detection center of the mark detection system MDS in the XY plane, respectively. Therefore, the occurrence of a so-called Abbe error caused by the deviation in the XY plane between the detection point and the detection center of the mark detection system MDS is suppressed to such an extent that it can be substantially ignored. Therefore, by using the first position measurement system 30, the control device 60 can accurately measure the positions of the slider 10 in the X-axis direction, the Y-axis direction, and the Z-axis direction without an Abbe error caused by the deviation in the XY plane between the detection point and the detection center of the mark detection system MDS.

[0064] However, regarding the Z-axis direction parallel to the optical axis AX1 of the mark detection system MDS, the position information of the slider 10 in the XY plane is not measured by the encoder system 33 at the position of the surface of the wafer W. That is, the Z positions of the arrangement plane of the grating RG1 and the surface of the wafer W do not match. Therefore, when the grating RG1 (i.e., the slider 10) is inclined with respect to the XY plane, if the slider 10 is positioned based on the measured values of the encoders of the encoder system 33, as a result, due to the difference ΔZ in the Z positions between the arrangement plane of the grating RG1 and the surface of the wafer W (i.e., the displacement in the Z-axis direction between the detection point by the encoder system 33 and the detection center (detection point) by the mark detection system MDS), a positioning error (a kind of Abbe error) corresponding to the inclination of the grating RG1 with respect to the XY plane will occur. However, this positioning error (position control error) can be obtained by a simple calculation using the difference ΔZ, the pitching amount θx, and the rolling amount θy. By using this as an offset and positioning the slider 10 based on the corrected position information obtained by correcting the measured values of the encoder system 33 (each encoder) by the offset amount, the slider 10 will not be affected by the above-mentioned kind of Abbe error. Alternatively, instead of correcting the measured values of the encoder system 33 (each encoder), one or more pieces of information for moving the slider, such as the target position where the slider 10 should be positioned, may be corrected based on the above offset.

[0065] In addition, when the grating RG1 (i.e., the slider 10) is inclined with respect to the XY plane, the head portion 32 may be moved so that no positioning error is caused due to the inclination. That is, when it is measured by the first position measurement system 30 (for example, the interferometer system 35) that the grating RG1 (i.e., the slider 10) is inclined with respect to the XY plane, the surface plate 12 holding the head portion 32 may be moved based on the position information obtained by using the first position measurement system 30. As described above, the surface plate 12 can be moved using the vibration isolation device 14.

[0066] Further, when the grating RG1 (i.e., the slider 10) is inclined with respect to the XY plane, the position information of the mark obtained using the mark detection system MDS may be corrected based on the positioning error caused by the inclination.

[0067] As shown in FIGS. 2, 3(A), and 3(B), the second position measurement system 50 includes a pair of head portions 52A and 52B respectively provided on the lower surfaces of one end portion and the other end portion in the longitudinal direction of the aforementioned head mounting member 51, and scale members 54A and 54B disposed opposite to the head portions 52A and 52B. The upper surfaces of the scale members 54A and 54B are at the same height as the surface of the wafer W held by the wafer holder WH. Reflection-type two-dimensional gratings RG2a and RG2b are formed on the upper surfaces of the scale members 54A and 54B respectively. The two-dimensional gratings (hereinafter abbreviated as gratings) RG2a and RG2b both include a reflection-type diffraction grating (X diffraction grating) having the X-axis direction as the periodic direction and a reflection-type diffraction grating (Y diffraction grating) having the Y-axis direction as the periodic direction. The pitch of the grating lines of the X diffraction grating and the Y diffraction grating is set to, for example, 1 μm.

[0068] The scale members 54A and 54B are made of a material with a low coefficient of thermal expansion, such as the aforementioned zero-expansion material, and are fixed on the surface plate 12 via support members 56 respectively as shown in FIGS. 3(A) and 3(B). In this embodiment, the dimensions of the scale members 54A and 54B and the support members 56 are determined such that the gratings RG2a and RG2b and the head portions 52A and 52B face each other with a gap of about several millimeters therebetween.

[0069] As shown in FIG. 6, one head portion 52A fixed to the lower surface of the +X side end of the head attachment member 51 includes an XZ head 58X1 with the X-axis and Z-axis directions as measurement directions and a YZ head 58Y1 with the Y-axis and Z-axis directions as measurement directions, both of which are housed inside the same housing. The XZ head 58X1 (more precisely, the irradiation point on the grating RG2a of the measurement beam emitted by the XZ head 58X1) and the YZ head 58Y1 (more precisely, the irradiation point on the two-dimensional grating RG2a of the measurement beam emitted by the YZ head 58Y1) are arranged on a straight line parallel to the same Y-axis.

[0070] The other head portion 52B is arranged symmetrically with respect to the head portion 52A with respect to a straight line (hereinafter referred to as the reference axis) LV parallel to the Y-axis passing through the optical axis AX1 of the mark detection system MDS, and has the same configuration as the head portion 52A. That is, the head portion 52B has an XZ head 58X2 and a YZ head 58Y2 arranged symmetrically with respect to the XZ head 58X1 and the YZ head 58Y1 with respect to the reference axis LV, and the irradiation points of the measurement beams irradiated onto the grating RG2b from the XZ head 58X2 and the YZ head 58Y2 respectively are set on a straight line parallel to the same Y-axis.

[0071] As each of the XZ heads 58X1 and 58X2 and the YZ heads 58Y1 and 58Y2, an encoder head having the same configuration as the displacement measurement sensor head disclosed in, for example, U.S. Patent No. 7,561,280 can be used.

[0072] The head portions 52A and 52B respectively constitute an XZ linear encoder that measures the X-axis position (X position) and Z-axis position (Z position) of the gratings RG2a and RG2b using scale members 54A and 54B, and a YZ linear encoder that measures the Y-axis position (Y position) and Z position. Here, the gratings RG2a and RG2b are formed on the upper surfaces of the scale members 54A and 54B respectively fixed on the surface plate 12 via support members 56, and the head portions 52A and 52B are provided on a head mounting member 51 integrated with the mark detection system MDS. As a result, the head portions 52A and 52B measure the position of the surface plate 12 relative to the mark detection system MDS (the positional relationship between the mark detection system MDS and the surface plate 12). Hereinafter, for convenience, the XZ linear encoder and the YZ linear encoder are denoted as XZ heads 58X1, 58X2, YZ heads 58Y1, 58Y2 respectively using the same reference numerals as the XZ linear encoders 58X1, 58X2, and the YZ linear encoders 58Y1, 58Y2 (see Fig. 7).

[0073] In this embodiment, an XZ linear encoder 58X1 and a YZ linear encoder 58Y1 constitute a four-axis encoder 581 that measures position information regarding the X-axis, Y-axis, Z-axis, and θx directions of the surface plate 12 relative to the mark detection system MDS (see Fig. 7). Similarly, an XZ linear encoder 58X2 and a YZ linear encoder 58Y2 constitute a four-axis encoder 582 that measures position information regarding the X-axis, Y-axis, Z-axis, and θx directions of the surface plate 12 relative to the mark detection system MDS (see Fig. 7). In this case, based on the position information regarding the Z-axis direction of the surface plate 12 relative to the mark detection system MDS measured by the four-axis encoders 581 and 582 respectively, position information regarding the θy direction of the surface plate 12 relative to the mark detection system MDS is obtained (measured), and based on the position information regarding the Y-axis direction of the surface plate 12 relative to the mark detection system MDS measured by the four-axis encoders 581 and 582 respectively, position information regarding the θz direction of the surface plate 12 relative to the mark detection system MDS is obtained (measured).

[0074] Therefore, the 4-axis encoder 581 and the 4-axis encoder 582 constitute a second position measurement system 50 that measures the position information in six degrees of freedom for the mark detection system MDS of the surface plate 12, that is, the information on the relative position between the mark detection system MDS and the surface plate 12 in six degrees of freedom. The information on the relative position between the mark detection system MDS and the surface plate 12 in six degrees of freedom measured by the second position measurement system 50 is constantly supplied to the control device 60. Based on this relative position information, the control device 60 makes the detection point of the first position measurement system 30 have a desired positional relationship with respect to the detection center of the mark detection system MDS. Specifically, the detection point of the first position measurement system 30 coincides with the detection center of the mark detection system MDS in the XY plane at a level of, for example, nm, and the surface of the wafer W on the slider 10 coincides with the detection position of the mark detection system MDS. The actuators of the three vibration isolation devices 14 are controlled in real time. At this time, for example, the aforementioned straight line CL coincides with the reference axis LV. Note that if the detection point of the first position measurement system 30 can be controlled to have a desired positional relationship with respect to the detection center of the mark detection system MDS, the second position measurement system 50 does not necessarily have to measure the relative position information in all six degrees of freedom.

[0075] As is clear from the description of the aforementioned first position measurement system 30 and the description of the above second position measurement system 50, in the measuring device 100, a position measurement system that measures the position information of the slider 10 in six degrees of freedom with respect to the mark detection system MDS is constituted by the first position measurement system 30 and the second position measurement system 50.

[0076] FIG. 7 shows a block diagram showing the input / output relationship of a control device 60 that centrally constitutes the control system of the measuring device 100 according to the present embodiment. The control device 60 includes a workstation (or a microcomputer) or the like and comprehensively controls each component of the measuring device 100. As shown in FIG. 7, the measuring device 100 includes a wafer transfer system 70 disposed in the chamber together with the components shown in FIG. 2. The wafer transfer system 70 is composed of, for example, a horizontal articulated robot.

[0077] Next, in the measuring device 100 according to the present embodiment configured as described above, a series of operations when processing one lot of wafers will be described based on the flowchart of FIG. 8 corresponding to the processing algorithm of the control device 60.

[0078] As a premise, the wafer W to be measured by the measuring device 100 is a 300-mm wafer. On the wafer W, a plurality of, for example, I (as an example, I = 98) partition regions called shot regions (hereinafter referred to as shots) are formed in a matrix arrangement by exposure before the previous layer. On the street line surrounding each shot or the street line inside each shot (in the case of multiple chips per shot), a plurality of types of marks are provided, such as search alignment marks (search marks) for search alignment and wafer alignment marks (wafer marks) for fine alignment. It is assumed that these multiple types of marks are formed together with the partition regions. In the present embodiment, 2D marks are used as the search marks and the wafer marks.

[0079] Also, it is assumed that the measuring device 100 can set a plurality of measurement modes in which the mark detection conditions by the mark detection system MDS are different from each other. As an example of the plurality of measurement modes, an A mode in which one wafer mark is detected for each shot of the entire wafer, and for the first predetermined number of wafers in the lot, a plurality of wafer marks are detected for all shots, and according to the detection results of the wafer marks, for the remaining wafers in the lot, the wafer mark to be detected is determined for each shot, and the determined wafer mark is detected, and a B mode can be set.

[0080] Also, it is assumed that information necessary for alignment measurement of the wafer W is input in advance by an operator of the measurement device 100 via an input device (not shown) and stored in the memory of the control device 60. Here, the information necessary for alignment measurement includes various information such as the thickness information of the wafer W, the flatness information of the wafer holder WH, and the design information of the arrangement of the shot regions and alignment marks on the wafer W. Note that the setting information of the measurement mode is assumed to be input in advance by an operator via an input device (not shown), for example.

[0081] The processing algorithm corresponding to the flowchart of FIG. 8 starts, for example, when the measurement device 100 receives a permission request for starting the transfer of one lot of wafers from the coating / development control device 320 of the C / D300 connected in-line, and the control device 60 responds to the request and the first wafer is carried into a predetermined transfer position (a first substrate transfer unit described later).

[0082] First, in step S102, the count value i of a counter indicating the number of the wafer in the lot is initialized to 1 (i←1).

[0083] In the next step S104, the wafer W is loaded onto the slider 10. This loading of the wafer W is performed by the wafer transfer system 70 and the vertical movement member on the slider 10 under the control of the control device 60. Specifically, the wafer W is transferred by the wafer transfer system 70 from the wafer carrier (or transfer position) above the slider 10 at the loading position, and the vertical movement member is driven to rise by a predetermined amount by the driving device 13, so that the wafer W is passed to the vertical movement member. Then, after the wafer transfer system 70 retreats from above the slider 10, the vertical movement member is driven to descend by the driving device 13, so that the wafer W is placed on the wafer holder WH on the slider 10. Then, the vacuum pump 11 is turned on, and the wafer W loaded on the slider 10 is vacuum-sucked by the wafer holder WH. When the measurement device 100 is connected in-line to a substrate processing device, wafers are sequentially carried in from the wafer transfer system on the substrate processing device side and placed at the transfer position.

[0084] In the next step S106, the position of the wafer W in the Z-axis direction (Z position) is adjusted. Prior to this adjustment of the Z position, based on the relative position information regarding the Z-axis direction, θy direction, and θx direction between the mark detection system MDS measured by the second position measurement system 50 and the surface plate 12 by the control device 60, the internal pressure of the air mounts of the three vibration isolation devices 14 (the driving force in the Z-axis direction generated by the vibration isolation device 14) is controlled, and the surface plate 12 is set such that its upper surface is parallel to the XY plane and the Z position becomes a predetermined reference position. The wafer W is considered to have a uniform thickness. Therefore, in step S106, the control device 60 adjusts the driving force in the Z-axis direction generated by the three vibration isolation devices 14, for example, the internal pressure of the air mounts (the amount of compressed air), based on the thickness information of the wafer W in the memory, so that the surface of the wafer W is set within the range where the focus position of the optical system can be adjusted by the autofocus function of the mark detection system MDS, drives the surface plate 12 in the Z-axis direction, and adjusts the Z position of the surface of the wafer W. When the measurement unit 40 is equipped with a focus position detection system, the control device 60 may also perform the Z position adjustment of the wafer surface based on the detection result (output) of the focus position detection system. For example, the mark detection system MDS may be equipped with a focus position detection system that detects the position of the wafer W surface in the Z-axis direction through the optical element (objective optical element) at the tip. Also, the adjustment of the Z position of the surface of the wafer W based on the detection result of the focus position detection system can be performed by moving the surface plate 12 using the vibration isolation device 14 and moving the slider 10 together with the surface plate 12. In addition, a drive system 20 configured to be able to drive the slider 10 not only in the direction within the XY plane but also in the Z-axis direction, θx direction, and θy direction may be adopted, and the slider 10 may be moved using the drive system 20. Note that the Z position adjustment of the wafer surface may include the adjustment of the inclination of the wafer surface. If there is a possibility of an error (a kind of Abbe error) caused by the difference ΔZ in the Z position between the arrangement surface of the grating RG1 and the surface of the wafer W when using the drive system 20 to adjust the inclination of the wafer surface, at least one of the above-mentioned countermeasures may be executed.

[0085] In the next step S108, search alignment of the wafer W is performed. Specifically, for example, at least two search marks located in the peripheral portion are detected using the mark detection system MDS, which are substantially symmetric with respect to the center of the wafer W. The control device 60 controls the driving of the slider 10 by the drive system 20 to position each search mark within the detection area (detection field of view) of the mark detection system MDS, while acquiring the measurement information by the first position measurement system 30 and the measurement information by the second position measurement system 50. Based on the detection signal when the search mark formed on the wafer W is detected using the mark detection system MDS and the measurement information (and the measurement information by the second position measurement system 50) by the first position measurement system 30, the position information of each search mark is obtained.

[0086] More specifically, the control device 60 determines the position coordinates of the two search marks in the reference coordinate system based on the detection result of the mark detection system MDS output from the signal processing device 49 (the relative positional relationship between the detection center (index center) of the mark detection system MDS obtained from the detection signal and each search mark) and the measurement values of the first position measurement system 30 (and the measurement values of the second position measurement system 50) at the time of detecting each search mark. Here, the reference coordinate system is a rectangular coordinate system defined by the measuring axis of the first position measurement system 30.

[0087] Thereafter, the residual rotation error of the wafer W is calculated from the position coordinates of the two search marks, and the slider 10 is slightly rotated so that this rotation error becomes substantially zero. Thereby, the search alignment of the wafer W is completed. Note that since the wafer W is actually loaded on the slider 10 in a pre-aligned state, the deviation of the center position of the wafer W is negligibly small, and the residual rotation error is extremely small.

[0088] In the next step S110, it is determined whether the set measurement mode is the A mode. If the determination in this step S110 is affirmative, that is, if the A mode is set, the process proceeds to step S112.

[0089] In step S112, alignment measurement for the entire wafer (measurement of one point for all shots, in other words, EGA measurement for all shots), that is, for each of the 98 shots, one wafer mark is measured. Specifically, the control device 60 obtains the position coordinates of the wafer mark on the reference coordinate system of the wafer W, that is, the position coordinates of the shot, in the same manner as the measurement of the position coordinates of each search mark during the search alignment described above. However, in this case, different from the search alignment, when calculating the position coordinates of the shot, the measurement information of the second position measurement system 50 is always used. The reason is that, as described above, based on the measurement information of the second position measurement system 50 by the control device 60, the detection point of the first position measurement system 30 coincides with the detection center of the mark detection system MDS in the XY plane at a level of, for example, nm, and the surface of the wafer W on the slider 10 coincides with the detection position of the mark detection system MDS. Thus, the actuators of the three vibration isolation devices 14 are controlled in real time. However, when detecting the wafer mark, there is no compensation for the coincidence of the detection point of the first position measurement system 30 and the detection center of the mark detection system MDS in the XY plane at a level of, for example, nm. Therefore, it is necessary to calculate the position coordinates of the shot by considering the amount of positional deviation between the two as an offset. For example, by using the above offset to correct the detection result of the mark detection system MDS or the measured value of the first position measurement system 30, the position coordinates of the wafer mark on the wafer W calculated on the reference coordinate system can be corrected.

[0090] Here, during this measurement of one point for all shots, the control device 60 moves the slider 10 (wafer W) in at least one of the X-axis direction and the Y-axis direction via the drive system 20 based on the measurement information of the first position measurement system 30 and the measurement information of the second position measurement system 50, and positions the wafer mark within the detection region of the mark detection system MDS. That is, the slider 10 is moved relative to the mark detection system MDS in the XY plane in a step-and-repeat manner, and the measurement of one point for all shots is performed.

[0091] In addition, when the measurement unit 40 includes a focus position detection system, similar to the description in step S106, the control device 60 may adjust the Z position of the wafer surface based on the detection result (output) of the focus position detection system.

[0092] During the alignment measurement for all wafers in step S112 (one-point measurement for all shots), when the slider 10 moves within the XY plane, an unbalanced load acts on the surface plate 12 as it moves. In this embodiment, the control device 60 individually performs feed-forward control on the three vibration isolation devices 14 so that the influence of the unbalanced load is canceled according to the X and Y coordinate positions of the slider included in the measurement information of the first position measurement system 30, and individually controls the driving force in the Z-axis direction generated by each vibration isolation device 14. Note that the control device 60 may predict the unbalanced load acting on the surface plate 12 based on the information on the known movement path of the slider 10 without using the measurement information of the first position measurement system 30, and individually perform feed-forward control on the three vibration isolation devices 14 so that the influence of the unbalanced load is canceled. Also, in this embodiment, since the information on the unevenness of the wafer holding surface of the wafer holder WH (the surface defined by the upper end surfaces of the many pins of the chuck) (hereinafter referred to as holder flatness information) has been obtained in advance through experiments or the like, when moving the slider 10 during alignment measurement (for example, one-point measurement for all shots), the control device 60 finely adjusts the Z position of the surface plate 12 by performing feed-forward control on the three vibration isolation devices 14 so that the region including the wafer mark to be measured on the surface of the wafer W is quickly positioned within the depth of focus range of the optical system of the mark detection system MDS. Note that either one or both of the feed-forward control for canceling the influence of the unbalanced load acting on the surface plate 12 described above and the feed-forward control based on the holder flatness information may not be executed.

[0093] In addition, when the magnification of the mark detection system MDS can be adjusted, it may be set to a low magnification during the search alignment and to a high magnification during the alignment measurement. Also, if the deviation of the center position of the wafer W loaded on the slider 10 and the residual rotational error are negligibly small, step S108 may be omitted.

[0094] In the measurement of one point per all shots in step S112, the measured values of the position coordinates of the sample shot area (sample shot) in the reference coordinate system, which are used in the EGA operation described later, will be detected. The sample shot refers to a plurality (at least three) of specific shots that are predetermined as those used in the EGA operation described later among all the shots on the wafer W. Note that in the measurement of one point per all shots, all the shots on the wafer W become sample shots. After step S112, the process proceeds to step S124.

[0095] On the other hand, if the determination in step S110 is negative, that is, when the B mode is set, the process proceeds to step S114, and it is determined whether the count value i is smaller than a predetermined number K (K is a natural number satisfying 1 < K < I, a predetermined number, for example, 4). Note that the count value i is incremented in step S128 described later. And if the determination in this step S114 is affirmative, the process proceeds to step S120, and the measurement of multiple points per all shots is performed. Here, the measurement of multiple points per all shots means measuring a plurality of wafer marks for each of all the shots on the wafer W. The plurality of wafer marks to be measured are predetermined. For example, a plurality of wafer marks arranged in such a way that the shape of the shot (shape error from the ideal lattice) can be obtained by statistical calculation may be used as the measurement targets. The measurement procedure is the same as that in the case of the measurement of one point per all shots in step S112 except for the difference in the number of marks to be measured, so the detailed description is omitted. After step S120, the process proceeds to step S124.

[0096] On the other hand, if the determination in step S114 is negative, the process proceeds to step S116 to determine whether the count value i is less than K + 1. Here, since the determination in this step S116 is affirmative when the count value i satisfies i ≧ K and i < K + 1, it is the case where i = K.

[0097] If the determination in step S116 is affirmative, the process proceeds to step S118, and based on the detection results of the wafer marks for the K - 1 wafers W (for example, 3 wafers when K = 4) that have been measured so far, the wafer mark to be measured for each shot is determined. Specifically, for each shot, it is determined whether the detection of one wafer mark is sufficient or whether a plurality of wafer marks should be detected. In the latter case, it is also determined which wafer mark should be the detection target. For example, for each shot, the difference (absolute value) between the actual measurement position and the design position of each of the plurality of wafer marks is obtained, and based on whether the difference between the maximum value and the minimum value of the difference exceeds a certain threshold, it is determined for each shot whether a plurality of wafer marks should be detected or whether the detection of one wafer mark is sufficient. In the former case, for example, the wafer marks to be detected are determined so as to include the wafer mark with the maximum difference between the actual measurement position and the design position (absolute value) and the wafer mark with the minimum difference. After step S118, the process proceeds to step S122.

[0098] On the other hand, if the determination in step S116 is negative, the process proceeds to step S122. Here, the determination in step S116 is negative when the count value i satisfies K + 1 ≦ i, and necessarily, before that, the count value i = K and the wafer mark to be measured for each shot has been determined in step S118.

[0099] In step S122, the wafer mark to be measured, which was determined for each shot in step S118, is measured. The measurement procedure is the same as that in the case of the one - point measurement for all shots in step S112, except for the difference in the number of marks to be measured, so the detailed description is omitted. After step S122, the process proceeds to step S124.

[0100] As can be seen from the above description, in the case of the B mode, for the wafers from the first to the (K - 1)-th (for example, the third) in the lot, full-shot multi-point measurement is performed. For the wafers from the K-th (for example, the fourth) to the I-th (for example, the 25-th), based on the results of the full-shot multi-point measurement of the first K - 1 (for example, 3) wafers, the measurement of the wafer marks determined for each shot will be performed.

[0101] In step S124, an EGA operation is performed using the position information of the wafer marks measured in any one of steps S112, S120, and S122. The EGA operation means a statistical operation that, after the above-described measurement of the wafer marks (EGA measurement), uses a statistical operation such as the least squares method based on the data of the difference between the designed value and the measured value of the position coordinates of the sample shot, and obtains the coefficients of the model formula that expresses the relationship between the position coordinates of the shot and the correction amount of the position coordinates of that shot.

[0102] In this embodiment, as an example, the following model formula is used to calculate the correction amount from the designed value of the position coordinates of the shot.

[0103]

Equation

[0104] Here, dx and dy are the correction amounts in the X-axis and Y-axis directions from the designed value of the position coordinates of the shot, and X and Y are the designed position coordinates of the shot in the wafer coordinate system with the center of the wafer W as the origin. That is, the above formula (1) is a polynomial regarding the designed position coordinates X and Y of each shot in the wafer coordinate system with the center of the wafer as the origin, and it is a model formula that expresses the relationship between the position coordinates X and Y and the correction amounts (alignment correction components) dx and dy of the position coordinates of that shot. In this embodiment, since the rotation between the reference coordinate system and the wafer coordinate system is canceled by the above-described search alignment, hereinafter, the reference coordinate system and the wafer coordinate system will not be particularly distinguished, and all will be described as the reference coordinate system.

[0105] Using the model formula (1), the correction amount of the position coordinates of the shot on the wafer W can be obtained from the position coordinates X and Y of the shot. However, in order to calculate this correction amount, it is necessary to obtain the coefficients a0, a1, …, b0, b1, …. After the EGA measurement, based on the data of the difference between the designed value and the measured value of the position coordinates of the sample shot, statistical operations such as the least squares method are used to obtain the coefficients a0, a1, …, b0, b1, … of the above formula (1).

[0106] After determining the coefficients a0, a1, …, b0, b1, … of the model formula (1), by substituting the designed position coordinates X and Y of each shot (section area) in the wafer coordinate system into the model formula (1) after coefficient determination, and obtaining the correction amounts dx and dy of the position coordinates of each shot, the true array (including not only the linear component but also the non-linear component as the deformation component) of a plurality of shots (section areas) on the wafer W can be obtained.

[0107] By the way, in the case of the wafer W on which exposure has already been performed, due to the influence of the previous processes, the waveforms of the detection signals obtained as the measurement results are not necessarily good for all wafer marks. If the positions of the wafer marks with such measurement results (waveforms of the detection signals) being poor are included in the above EGA operation, the position errors of the wafer marks with such measurement results (waveforms of the detection signals) will have an adverse effect on the calculation results of the coefficients a0, a1, …, b0, b1, ….

[0108] Therefore, in the present embodiment, the signal processing device 49 sends only the measurement results of the wafer marks with good measurement results to the control device 60, and the control device 60 executes the above-described EGA operation using the positions of all the wafer marks for which the measurement results have been received. Note that there is no particular limitation on the degree of the polynomial of the above formula (1). The control device 60 creates the result of the EGA operation as an alignment history data file in association with the information regarding the marks used in the operation and the identification information of the wafer (for example, wafer number, lot number), and stores it in an internal or external storage device.

[0109] When the EGA operation in step S124 is completed, the process proceeds to step S126, and the wafer W is unloaded from the slider 10. This unloading is performed by the wafer transfer system 70 and the vertical moving member on the slider 10 in a procedure opposite to the loading procedure in step S104 under the control of the control device 60.

[0110] In the next step S128, after incrementing the count value i of the counter by 1 (i←i + 1), the process proceeds to step S130 to determine whether the count value i is greater than the total number I of wafers in the lot. If the determination in this step S130 is negative, it is determined that the processing for all the wafers in the lot has not been completed, and the process returns to step S104, and the processing (including the determination) from step S104 to step S130 is repeated until the determination in step S130 is affirmative.

[0111] When the determination in step S130 is affirmative, it is determined that the processing for all the wafers in the lot has been completed, and a series of processes of this routine are terminated.

[0112] As can be seen from the above description, according to the measuring device 100, at the time of alignment measurement, for each of the I (for example, 98) shots on the wafer W, at least the position information of each one wafer mark is measured, and using this position information, the coefficients a0, a1,..., b0, b1,... of the above formula (1) are obtained by statistical operations such as the least squares method. Therefore, it becomes possible to accurately obtain the deformation component of the wafer grid not only for the linear component but also for the non-linear component. Here, the wafer grid means a grid formed by connecting the centers of the shots on the wafer W arranged according to the shot map (data regarding the arrangement of the shots formed on the wafer W). Obtaining the correction amounts (alignment correction components) dx and dy of the position coordinates of the shots for a plurality of shots is nothing but obtaining the deformation component of the wafer grid.

[0113] The exposure apparatus 200 is, as an example, a step-and-scan type projection exposure apparatus (scanner). In FIG. 9, the components inside the chamber of the exposure apparatus 200 are shown with some omissions.

[0114] As shown in FIG. 9, the exposure apparatus 200 includes an illumination system IOP, a reticle stage RST that holds a reticle R, a projection unit PU that projects an image of a pattern formed on the reticle R onto a wafer W coated with a photosensitive agent (resist), a wafer stage WST that holds the wafer W and moves within the XY plane, and a control system for these components. The exposure apparatus 200 includes a projection optical system PL having an optical axis AX in the Z-axis direction parallel to the optical axis AX1 of the aforementioned mark detection system MDS.

[0115] The illumination system IOP includes a light source and an illumination optical system connected to the light source via a light transmission optical system, and illuminates a slit-shaped illumination region IAR that extends longitudinally in the X-axis direction (the direction perpendicular to the plane of the paper in FIG. 9) on the reticle R set (restricted) by a reticle blind (masking system) with substantially uniform illuminance using illumination light (exposure light) IL. The configuration of the illumination system IOP is disclosed, for example, in U.S. Patent Application Publication No. 2003 / 0025890. Here, as the illumination light IL, for example, ArF excimer laser light (wavelength 193 nm) is used.

[0116]

[0117] The reticle stage RST is disposed below the illumination system IOP in FIG. 9. The reticle stage RST can be micro-driven within a horizontal plane (XY plane) on a reticle stage surface plate (not shown) by a reticle stage drive system 211 (not shown in FIG. 9, see FIG. 10) including, for example, a linear motor, and can be driven within a predetermined stroke range in the scanning direction (the Y-axis direction which is the left-right direction within the plane of the paper in FIG. 9).On the reticle stage RST, a reticle R is placed, on which a pattern region and a plurality of marks with a known positional relationship to the pattern region are formed on the -Z side surface (pattern surface). The position information (including the rotation information in the θz direction) in the XY plane of the reticle stage RST is constantly detected by a reticle laser interferometer (hereinafter referred to as "reticle interferometer") 214, via a moving mirror 212 (or a reflecting surface formed on the end face of the reticle stage RST), with a resolution of about 0.25 nm, for example. The measurement information of the reticle interferometer 214 is supplied to an exposure control device 220 (see FIG. 10). Note that the position information in the XY plane of the reticle stage RST described above may be measured by an encoder instead of the reticle laser interferometer 214.

[0118] The projection unit PU is disposed below the reticle stage RST in FIG. 9. The projection unit PU includes a lens barrel 240 and a projection optical system PL held within the lens barrel 240. The projection optical system PL is, for example, telecentric on both sides and has a predetermined projection magnification (such as 1 / 4 times, 1 / 5 times, or 1 / 8 times). The reticle R is arranged such that the first surface (object surface) of the projection optical system PL and the pattern surface substantially coincide, and the wafer W coated with a resist (sensitizer) on its surface is disposed on the second surface (image surface) side of the projection optical system PL. Therefore, when the illumination region IAR on the reticle R is illuminated by the illumination light IL from the illumination system IOP, the reduced image (reduced image of a part of the circuit pattern) of the circuit pattern of the reticle R within the illumination region IAR is formed, via the projection optical system PL, on the region (hereinafter also referred to as the exposure region) IA on the wafer W conjugate to the illumination region IAR by the illumination light IL that has passed through the reticle R. Then, by the synchronous driving of the reticle stage RST and the wafer stage WST, the reticle R is relatively moved in the scanning direction (Y-axis direction) with respect to the illumination region IAR (illumination light IL), and the wafer W is relatively moved in the scanning direction (Y-axis direction) with respect to the exposure region IA (illumination light IL), so that the scanning exposure of one shot region (section region) on the wafer W is performed, and the pattern of the reticle R is transferred to the shot region.

[0119] As an example of the projection optical system PL, a refractive system composed only of a plurality of, for example, about 10 to 20 refractive optical elements (lens elements) arranged along the optical axis AX parallel to the Z-axis direction is used. Among the plurality of lens elements constituting the projection optical system PL, a plurality of lens elements on the object plane side (reticle R side) are shift-driven in the Z-axis direction (the optical axis direction of the projection optical system PL) and driven in the tilt directions with respect to the XY plane (that is, the θx direction and the θy direction) by a driving element (not shown), such as a piezo element. Then, an imaging characteristic correction controller 248 (not shown in FIG. 9, see FIG. 10) independently adjusts the applied voltage to each driving element based on an instruction from the exposure control device 220, so that each movable lens is individually driven and various imaging characteristics (magnification, distortion aberration, spherical aberration, coma aberration, field curvature, etc.) of the projection optical system PL are adjusted. Instead of or in addition to the movement of the movable lens, an airtight chamber may be provided between specific adjacent lens elements inside the lens barrel 240, and the imaging characteristic correction controller 248 may control the pressure of the gas in the airtight chamber, or a configuration in which the imaging characteristic correction controller 248 can shift the center wavelength of the illumination light IL may be adopted. With these configurations, it is also possible to adjust the imaging characteristics of the projection optical system PL.

[0120] The wafer stage WST is driven on the wafer stage surface plate 222 in the X-axis direction and the Y-axis direction with a predetermined stroke by a stage drive system 224 (shown as a block for convenience in FIG. 9) including a planar motor or a linear motor, etc., and is also driven minutely in the Z-axis direction, the θx direction, the θy direction, and the θz direction. A wafer W is held on the wafer stage WST by vacuum adsorption or the like via a wafer holder (not shown). In this embodiment, it is assumed that the wafer holder can adsorb and hold a 300-mm wafer. Instead of the wafer stage WST, a stage device including a first stage that moves in the X-axis direction, the Y-axis direction, and the θz direction and a second stage that moves minutely in the Z-axis direction, the θx direction, and the θy direction on the first stage can also be used. Note that either one or both of the wafer stage WST and the wafer holder of the wafer stage WST may be referred to as the "second substrate holding member".

[0121] Position information within the XY plane of the wafer stage WST (including rotational information (yaw amount (rotation amount θz in the θz direction), pitching amount (rotation amount θx in the θx direction), rolling amount (rotation amount θy in the θy direction))) is constantly detected by a laser interferometer system (hereinafter abbreviated as the interferometer system) 218 with a resolution of about 0.25 nm, for example, via a movable mirror 216 (or a reflecting surface formed on the end face of the wafer stage WST). Note that the position information within the XY plane of the wafer stage WST may be measured by an encoder system instead of the interferometer system 218.

[0122] The measurement information of the interferometer system 218 is supplied to the exposure control device 220 (see FIG. 10). Based on the measurement information of the interferometer system 218, the exposure control device 220 controls the position (including rotation in the θz direction) within the XY plane of the wafer stage WST via the stage drive system 224.

[0123] Although not shown in FIG. 9, the position and tilt amount in the Z-axis direction of the surface of the wafer W are measured by a focus sensor AFS (see FIG. 10) composed of an oblique incidence type multi-point focus position detection system disclosed in, for example, U.S. Patent No. 5,448,332. The measurement information of this focus sensor AFS is also supplied to the exposure control device 220 (see FIG. 10).

[0124] A reference plate FP whose surface is at the same height as the surface of the wafer W is fixed on the wafer stage WST. On the surface of this reference plate FP, a first reference mark used for baseline measurement of the alignment detection system AS and a pair of second reference marks detected by a reticle alignment detection system described later are formed.

[0125] On the side of the lens barrel 240 of the projection unit PU, an alignment detection system AS for detecting the alignment marks or the first reference marks formed on the wafer W is provided. As the alignment detection system AS, for example, a type of imaging alignment sensor of the image processing method that illuminates the marks with broadband (wideband) light such as a halogen lamp and measures the mark positions by performing image processing on the images of the marks, namely, the FIA (Field Image Alignment) system, is used. Note that, instead of the alignment detection system AS of the image processing method, or together with the alignment detection system AS, a diffraction light interference type alignment system may be used.

[0126] In the exposure apparatus 200, further, above the reticle stage RST, a pair of reticle alignment detection systems 213 (not shown in FIG. 9, see FIG. 10) capable of simultaneously detecting a pair of reticle marks at the same Y position on the reticle R placed on the reticle stage RST are provided at a predetermined distance apart in the X-axis direction. The detection results of the marks by the reticle alignment detection systems 213 are supplied to the exposure control apparatus 220.

[0127] FIG. 10 shows the input / output relationship of the exposure control apparatus 220 in a block diagram. As shown in FIG. 10, the exposure apparatus 200 includes, in addition to each of the above-described components, a wafer transfer system 270 that transfers wafers and is connected to the exposure control apparatus 220. The exposure control apparatus 220 includes a microcomputer or a workstation, etc., and comprehensively controls the entire apparatus including each of the above-described components. The wafer transfer system 270 is composed of, for example, a horizontal articulated robot.

[0128] Returning to FIG. 1, although not shown, C / D 300 includes, for example, a coating unit that applies a sensitizer (resist) to a wafer, a developing unit capable of developing the wafer, a baking unit that performs pre-baking (PB) and post-exposure baking (PEB), and a wafer transfer system (hereinafter, referred to as the in-C / D transfer system for convenience). C / D 300 further includes a temperature control unit 330 capable of controlling the temperature of the wafer. The temperature control unit 330 is usually a cooling unit and includes, for example, a flat plate (temperature control device) called a cool plate. The cool plate is cooled, for example, by the circulation of cooling water. In addition, electronic cooling using the Peltier effect may also be used.

[0129] The storage device 400 includes a management device connected to the LAN 500 and a storage device connected to the management device via a communication path such as SCSI.

[0130] In the lithography system 1000 according to the present embodiment, the measurement device 100, the exposure device 200, and C / D 300 are all provided with barcode readers (not shown). During the transfer of each wafer by the wafer transfer system 70 (see FIG. 7), the wafer transfer system 270 (see FIG. 10), and the in-C / D transfer system (not shown), the barcode reader appropriately reads the identification information of each wafer, such as the wafer number, lot number, etc. Hereinafter, for the sake of simplicity of explanation, the description regarding the reading of the identification information of each wafer using the barcode reader will be omitted.

[0131] In the lithography system 1000, a large number of wafers are continuously processed by each of the exposure device 200, C / D 300, and measurement device 100 (hereinafter, also referred to as the three devices 100, 200, 300 as appropriate). In the lithography system 1000, the overall processing sequence is determined so that the throughput of the entire system is maximized, that is, for example, the processing times of other devices completely overlap with the processing time of the device that takes the most time for processing.

[0132] The following describes the operation flow when the lithography system 1000 continuously processes a large number of wafers.

[0133] First, the first wafer (referred to as W1) is taken out from the wafer carrier placed in the chamber of the C / D 300 by the in-C / D transfer system (e.g., a scalar robot) and carried into the coating section. Thereby, the coating of the resist is started by the coating section. When the coating of the resist is completed, the in-C / D transfer system takes out the wafer W1 from the coating section and carries it into the baking section. Thereby, the heat treatment (PB) of the wafer W1 is started in the baking section. Then, when the PB of the wafer is completed, the wafer W1 is taken out from the baking section by the in-C / D transfer system and carried into the temperature control section 330. Thereby, the cooling of the wafer W1 is started by the cooling plate inside the temperature control section 330. This cooling is performed with the target temperature being the target temperature of the air conditioning system of the exposure apparatus 200, which is a temperature range that has no influence in the exposure apparatus 200, generally, for example, in the range of 20 to 25°C. Usually, when the wafer is carried into the temperature control section 330, the temperature of the wafer is within the range of ±0.3 [°C] with respect to the target temperature, but the temperature is controlled to be within the range of the target temperature ±10 [mK] by the temperature control section 330.

[0134] Then, when the cooling (temperature control) is completed in the temperature control section 330, the wafer W1 is placed on the first substrate transfer section provided between the C / D 300 and the measuring device 100 by the in-C / D transfer system.

[0135] In the C / D 300, a series of resist coating, PB, cooling, and the above-described wafer transfer operations associated with these series of processes for the wafers are sequentially repeated in the same manner as above, and the wafers are sequentially placed on the first substrate transfer section. In practice, by providing two or more coating sections and in-C / D transfer systems in the chamber of the C / D 300, parallel processing of a plurality of wafers is possible, and the time required for the pre-exposure process can be shortened.

[0136] In the measuring device 100, the wafer W1 before exposure that is sequentially placed on the first substrate transfer section by the C / D internal transfer system is loaded onto the slider 10 in the procedure described in the first embodiment by the joint operation of the wafer transfer system 70 and the vertical movement member on the slider 10. After the loading, the measuring device 100 performs alignment measurement of the wafer in the set measurement mode, and the control device 60 obtains the correction amounts of the position coordinates of the shots of the wafer W (the coefficients a0, a1,..., b0, b1,... in the above formula (1)).

[0137] The control device 60 associates the obtained correction amounts of the position coordinates (the coefficients a0, a1,..., b0, b1,... in the above formula (1)), the information of the wafer marks in which the position information of the marks was used for the calculation of the correction amounts, the information of the measurement mode, and the history information such as the information of all the wafer marks for which the detection signals were good with the identification information (wafer number, lot number) of the wafer W1 to create alignment history data (file), and stores it in the storage device 400.

[0138] After that, the wafer W1 for which the alignment measurement has been completed is placed on the load-side substrate placement section of the second substrate transfer section provided near the measuring device 100 inside the chamber of the exposure device 200 by the wafer transfer system 70. Here, the second substrate transfer section is provided with a load-side substrate placement section and an unload-side substrate placement section.

[0139] Thereafter, in the measuring device 100, for the second and subsequent wafers, alignment measurement, creation of alignment history data (file), and wafer transfer are repeatedly performed in the same procedure as for the wafer W1.

[0140] The wafer W1 placed on the aforementioned load-side substrate placement unit is transported by the wafer transfer system 270 to a predetermined standby position inside the exposure apparatus 200. However, the first wafer W1 is directly loaded onto the wafer stage WST by the exposure control device 220 without waiting at the standby position. This wafer loading is performed by the exposure control device 220 using a vertical movement member (not shown) on the wafer stage WST and the wafer transfer system 270 in the same manner as performed by the measurement device 100 described above. After loading, the same search alignment as described above and wafer alignment of the EGA method with, for example, about 3 to 16 shots as alignment shots are performed on the wafer on the wafer stage WST using the alignment detection system AS. During this wafer alignment of the EGA method, the exposure control device 220 of the exposure apparatus 200 searches for the alignment history data file stored in the storage device 400 using the identification information (e.g., wafer number, lot number) of the wafer (target wafer) to be subjected to wafer alignment and exposure as a key, and acquires the alignment history data of the target wafer. Then, after performing a predetermined preparation operation, the exposure control device 220 performs wafer alignment as described below according to the measurement mode information included in the acquired alignment history data.

[0141] Here, prior to the specific description of wafer alignment, the reason why wafer alignment of the EGA method with about 3 to 16 shots as alignment shots is performed in the exposure apparatus 200 will be described.

[0142] The correction amounts of the position coordinates of the shots of the wafer W obtained by the measurement device 100 (the coefficients a0, a1, …, b0, b1, … in the above formula (1)) are used, for example, for wafer alignment with respect to the exposure position when the wafer W is exposed by the exposure device 200. However, the wafer W whose correction amount of the position coordinates is measured by the measurement device 100 by the exposure device 200 is unloaded from the slider 10 as described above for exposure and then loaded onto the wafer stage WST of the exposure device 200. In this case, even if the same type of wafer holder is used for the wafer holder WH on the slider 10 and the wafer holder on the wafer stage WST of the exposure device 200, the holding state of the wafer W is different due to individual differences in the wafer holders. Therefore, even if the correction amounts of the position coordinates of the shots of the wafer W (the coefficients a0, a1, …, b0, b1, … in the above formula (1)) are obtained by the measurement device 100, all of the coefficients a0, a1, …, b0, b1, … cannot be used as they are. However, it is considered that the low-order components (linear components) of the correction amounts of the position coordinates of the shots, which are affected by the different holding states of the wafer W for each wafer holder, are components of the first order or lower, and the higher-order components of the second order or higher are hardly affected. The reason is that the higher-order components of the second order or higher are considered to be components that occur mainly due to the deformation of the wafer W caused by the process, and can be considered as components independent of the holding state of the wafer by the wafer holder.

[0143] Based on such a consideration, the coefficients a3, a4, ……, a9, ……, and b3, b4, ……, b9, …… of the higher-order components obtained for the wafer W over time by the measurement device 100 can be used as they are also as the coefficients of the higher-order components of the correction amounts of the position coordinates of the wafer W in the exposure device 200. Therefore, on the wafer stage WST of the exposure device 200, it is sufficient to perform a simple EGA measurement (for example, measurement of about 3 to 16 wafer marks) to obtain the linear component of the correction amount of the position coordinates of the wafer W.

[0144] First, the case where the information of mode A is included will be described. In this case, from the wafer marks in the alignment history data for which the position information was measured by the measuring device 100 (the position information of the marks was used for calculating the correction amount), a number of wafer marks corresponding to the number of alignment shots are selected as detection targets, and the detection target wafer marks are detected using the alignment detection system AS. Based on the detection results and the position of the wafer stage WST at the time of detection (measurement information by the interferometer system 218), the position information of each detection target wafer mark is obtained. Using this position information, an EGA operation is performed to obtain each coefficient of the following formula (2).

[0145] [Number]

[0146] Then, the exposure control device 220 replaces the coefficients (c0, c1, c2, d0, d1, d2) obtained here with the coefficients (a0, a1, a2, b0, b1, b2) included in the alignment history data, and uses a polynomial regarding the designed position coordinates X, Y of each shot in the wafer coordinate system with the center of the wafer as the origin, which is represented by the following formula (3) including the replaced coefficients, to obtain the correction amounts (alignment correction components) dx, dy of the position coordinates of each shot. Based on this correction amount, for each shot when exposing the wafer grid, the target position (hereinafter, for convenience, referred to as the positioning target position) for alignment with respect to the exposure position (projection position of the reticle pattern) is determined. In this embodiment, exposure is performed using a scanning exposure method instead of a stationary exposure method, but it is referred to as the positioning target position for convenience.

[0147] [Number]

[0148] In the exposure apparatus 200 as well, since the rotation between the reference coordinate system (stage coordinate system) that defines the movement of the wafer stage WST and the wafer coordinate system is canceled by the search alignment, there is no need to particularly distinguish between the reference coordinate system and the wafer coordinate system.

[0149] Next, the case where the B mode is set will be described. In this case, the exposure control device 220 determines the positioning target position for each shot for correcting the wafer grid according to the same procedure as in the above-described A mode. However, in this case, among the multiple wafer marks for some shots and one wafer mark for each of the remaining shots in the alignment history data, the wafer mark with a good detection signal is included as the wafer mark for which the position information of the mark is used in the calculation of the correction amount.

[0150] Therefore, in addition to determining the positioning target position for each shot described above, the exposure control device 220 selects the number of wafer marks necessary for obtaining the shot shape from among the multiple wafer marks for some of the above-described shots, and uses the position information (measured values) of those wafer marks to perform a statistical operation (also called an in-shot multi-point EGA operation) in which the least squares method is applied to the model formula of [Equation 7] disclosed in, for example, U.S. Patent No. 6,876,946 to obtain the shot shape. Specifically, among the 10 parameters in the model formula of [Equation 7] disclosed in the above U.S. Patent No. 6,876,946, the chip rotation (θ), the chip orthogonality error (w), the chip scaling in the x direction (rx), and the chip scaling in the y direction (ry) are obtained. Note that since the in-shot multi-point EGA operation is disclosed in detail in the above U.S. Patent, a detailed description thereof will be omitted.

[0151] Then, while position - controlling the wafer stage WST according to the positioning target position, the exposure control device 220 performs exposure on each shot on the wafer W1 in a step - and - scan manner. Here, when the shot shape is also obtained by in - shot multi - point EGA measurement, during the scanning exposure, at least one of the relative scanning angle between the reticle stage RST and the wafer stage WST, the scanning speed ratio, the relative position of at least one of the reticle stage RST and the wafer stage WST with respect to the projection optical system, the imaging characteristics (aberration) of the projection optical system PL, and the wavelength of the illumination light (exposure light) IL is adjusted so that the projection image of the pattern of the reticle R by the projection optical system PL is deformed according to the obtained shot shape. Here, the adjustment of the imaging characteristics (aberration) of the projection optical system PL and the adjustment of the central wavelength of the illumination light IL are performed by the exposure control device 220 via the imaging characteristics correction controller 248.

[0152] In parallel with the EGA wafer alignment and exposure being performed on the wafer (in this case, wafer W1) on the wafer stage WST described above, the measuring device 100 performs wafer alignment measurement in the set mode, creates alignment history data, etc. on the second wafer (referred to as wafer W2) according to the procedures described above.

[0153] Before the exposure of the wafer (in this case, wafer W1) on the wafer stage WST is completed, the measurement process of the measuring device 100 is completed, and the second wafer W2 is placed on the load - side substrate placement portion by the wafer transfer system 70, transported to a predetermined standby position inside the exposure apparatus 200 by the wafer transfer system 270, and waits at that standby position.

[0154] When the exposure of the wafer W1 is completed, the wafers W1 and W2 are exchanged on the wafer stage, and the same wafer alignment and exposure as described above are performed on the exchanged wafer W2. If the transfer of the wafer W2 to the standby position is not completed by the time the exposure of the wafer (in this case, wafer W1) on the wafer stage is completed, the wafer stage will wait near the standby position while holding the exposed wafer.

[0155] In parallel with the wafer alignment for the wafer W2 after the above exchange, the exposed wafer W1 is transported by the wafer transfer system 270 to the unloading-side substrate placement section of the second substrate transfer section.

[0156] Thereafter, as described above, the wafer transfer system 70, in parallel with the alignment measurement of the wafer by the measurement device 100, transports and places the exposed wafer from the unloading-side substrate placement section onto the first substrate transfer section, and repeats, in a predetermined order, the operation of taking out the wafer before exposure after the measurement from the slider 10 and transporting it to the loading-side substrate placement section.

[0157] As described above, the exposed wafer transported and placed on the first substrate transfer section by the wafer transfer system 70 is carried into the baking section by the C / D internal transfer system, and PEB is performed by the baking device in the baking section. A plurality of wafers can be accommodated in the baking section simultaneously.

[0158] On the other hand, the wafer after the completion of PEB is taken out from the baking section by the C / D internal transfer system, carried into the developing section, and development is started by the developing device in the developing section.

[0159] When the development of the wafer is completed, the wafer is taken out from the developing section by the C / D internal transfer system and carried into a predetermined storage stage in the wafer carrier. Thereafter, in the C / D 300, for the exposed second and subsequent wafers, PEB, development, and wafer transfer are repeatedly performed in the same procedure as for the wafer W1.

[0160] As described above, according to the lithography system 1000 according to the present embodiment, while the wafer processing operation by the exposure apparatus 200 including the above-described simple EGA measurement and exposure is being performed, the alignment measurement of the wafer can be performed by the measurement apparatus 100, and efficient processing can be achieved with almost no reduction in the throughput of wafer processing. Moreover, in the measurement apparatus 100, the all-shot EGA with all shots as sample shots can be performed in parallel with the wafer alignment and exposure operations of the exposure apparatus 200. Further, since the coefficients of the higher-order components in the model formula obtained by the all-shot EGA can also be directly adopted in the exposure apparatus 200, in the exposure apparatus 200, only the alignment measurement with several shots as alignment shots is performed to obtain the coefficients of the lower-order components of the above model formula, and by using the coefficients of the lower-order components and the coefficients of the higher-order components acquired by the measurement apparatus 100, not only the coefficients (undetermined coefficients) of the lower-order components but also the coefficients (undetermined coefficients) of the higher-order components of the model formula (1) can be determined. Using the model formula (1) (i.e., the above formula (3)) in which these undetermined coefficients are determined and the design values (X, Y) of the arrangement of a plurality of shots on the wafer, the correction amount from the designed position of each shot can be obtained. As a result, it becomes possible to acquire a correction amount with the same high accuracy as when the coefficients of the lower-order and higher-order components of the model formula (1) are obtained in the exposure apparatus 200. Then, based on this correction amount and the design values of the arrangement of a plurality of shots on the wafer, it becomes possible to calculate the positioning target position at the time of exposure of each shot. Therefore, by controlling the position of the wafer stage WST according to this target position, each shot can be accurately aligned with the exposure position (projection position of the reticle pattern). As a result, it becomes possible to improve the overlay accuracy between the image of the pattern of the reticle at the time of exposure and the pattern formed in each shot region on the wafer without reducing the throughput of the exposure apparatus 200.

[0161] According to the measuring device 100 according to the present embodiment, while the control device 60 controls the movement of the slider 10 by the drive system 20, it uses the first position measurement system 30 and the second position measurement system 50 to obtain the position information of the slider 10 with respect to the surface plate 12 and the relative position information between the mark detection system MDS and the surface plate 12, and also obtains the position information of a plurality of marks formed on the wafer W using the mark detection system MDS. Therefore, according to the measuring device 100, the position information of a plurality of marks formed on the wafer W can be accurately obtained.

[0162] According to the measuring device 100 according to the present embodiment, the control device 60 constantly obtains the measurement information by the second position measurement system 50 (the relative position information between the surface plate 12 and the mark detection system MDS), and the position relationship between the detection center of the mark detection system MDS and the measurement points of the first position measurement system that detects the six-degree-of-freedom direction position information of the slider 10 with respect to the surface plate 12 is maintained in a desired relationship at the nm level. The position of the surface plate 12 in the six-degree-of-freedom direction is controlled in real time via three vibration isolation devices 14 (actuators). Also, while the control device 60 controls the driving of the slider 10 by the drive system 20, it obtains the measurement information by the first position measurement system 30 (the position information of the slider 10 with respect to the surface plate 12) and the measurement information by the second position measurement system 50 (the relative position information between the surface plate 12 and the mark detection system MDS), and based on the detection signal when detecting the marks formed on the wafer W using the mark detection system MDS, the measurement information by the first position measurement system 30 obtained when detecting the marks formed on the wafer W using the mark detection system MDS, and the measurement information by the second position measurement system 50 obtained when detecting the marks formed on the wafer W using the mark detection system MDS, it obtains the position information of a plurality of wafer marks. Therefore, according to the measuring device 100, the position information of a plurality of marks formed on the wafer W can be accurately obtained.

[0163] For example, when performing position control of the wafer W (wafer stage WST) during exposure based on the measured position information of the mark without performing EGA calculation using the measured position information of the mark, the measurement information by the second position measurement system 50 described above may not be used for calculating the position information of the mark. However, in this case, the measurement information by the second position measurement system 50 obtained when detecting the mark formed on the wafer W using the mark detection system MDS may be offset and used to correct information for moving the wafer W, such as the positioning target value of the wafer W (wafer stage WST). Alternatively, considering the above offset, it may be possible to control the movement of the reticle R (reticle stage RST) during exposure.

[0164] Further, according to the measuring apparatus 100 according to the present embodiment, the first position measurement system 30 for measuring the position information of the slider 10 in the six-degree-of-freedom direction on which the wafer W is placed and held detects at least the wafer mark on the wafer W by the mark detection system MDS. Therefore, within the range where the slider 10 moves, the measurement beam can be continuously irradiated from the head portion 32 to the grating RG1. Therefore, the first position measurement system 30 can continuously measure the position information within the entire range in the XY plane where the slider 10 moves for mark detection. Therefore, for example, at the manufacturing stage of the measuring apparatus 100 (including the start-up stage of the apparatus in the semiconductor manufacturing factory), by performing origin setting of the orthogonal coordinate system (reference coordinate system) defined by the measuring axis of the first position measurement system 30, the absolute position of the slider 10, and thus the absolute position of the mark on the wafer W held on the slider 10 (including not only the search mark and wafer mark but also other marks, such as the overlay measurement mark (registration mark), etc.) obtained from the position information of the slider 10 and the detection result of the mark detection system MDS can be managed on the reference coordinate system. In this specification, the "absolute position" means the coordinate position on the reference coordinate system.

[0165] In the lithography system 1000 according to the present embodiment, for example, when not reducing the throughput of wafer processing of the entire lithography system 1000 more than necessary, the developed wafer may be loaded again onto the slider 10 of the measuring device 100 in the same procedure as the wafer before exposure after the above-described PB, and the misalignment measurement of the overlay misalignment measurement marks (for example, box-in-box marks, etc.) formed on the wafer may be performed. That is, since the measuring device 100 can measure the absolute value of the marks on the wafer (in the reference coordinate system by the first position measurement system 30), it is suitable not only as a measuring device for wafer alignment measurement but also as a measuring device for measuring the misalignment of the overlay misalignment measurement marks, which is a kind of relative position measurement.

[0166] In the lithography system 1000 according to the above embodiment, the case where the exposure apparatus 200 obtains the coefficients of the lower-order components of the first order or less of the above model formula and uses the coefficients of the lower-order components and the coefficients of the higher-order components of the second order or more of the above model formula obtained by the measuring device 100 has been described. However, the present invention is not limited to this. For example, the coefficients of the components of the second order or less of the above model formula may be obtained from the detection result of the alignment marks in the exposure apparatus 200, and the coefficients of the components of the second order or less and the coefficients of the higher-order components of the third order or more of the above model formula obtained by the measuring device 100 may be used. Alternatively, for example, the coefficients of the components of the third order or less of the above model formula may be obtained from the detection result of the alignment marks in the exposure apparatus 200, and the coefficients of the components of the third order or less and the coefficients of the higher-order components of the fourth order or more of the above model formula obtained by the measuring device 100 may be used. That is, the coefficients of the components of the (N - 1)th order (N is an integer of 2 or more) or less of the above model formula may be obtained from the detection result of the alignment marks in the exposure apparatus 200, and the coefficients of the components of the (N - 1)th order or less and the coefficients of the higher-order components of the Nth order or more of the above model formula obtained by the measuring device 100 may be used.

[0167] In the above embodiment, the measuring device 100 determines the coefficients a3, a4, a5... and b3, b4, b5... of the higher-order components of the second order or higher and the coefficients a0, a1, a2, b0, b1, b2 of the lower-order components of the first order or lower in the model formula (1) that expresses the relationship between the designed position coordinates X, Y of each shot in the wafer coordinate system (coinciding with the reference coordinate system) and the correction amount (alignment correction component) dx, dy of the position coordinates of the shot. However, since the coefficients of the lower-order components are determined by the exposure device 200, the measuring device 100 does not necessarily have to determine the coefficients of the lower-order components.

[0168] In the above embodiment, when the B mode is set in the measuring device 100 and the position information of a plurality of wafer marks for some shots on the wafer is measured, the exposure device 200 obtains the chip rotation (θ), the chip orthogonality error (w), and the chip scaling in the x direction (rx) and the chip scaling in the y direction (ry) by performing the in-shot multi-point EGA operation, and thereby obtains the shape of the shot. However, it is not limited to this. For example, even when the A mode is set in the measuring device 100 and the position information of each one wafer mark is measured for all the shots on the wafer, the exposure device 200 can estimate the deformation of the shot (the shape change of the shot). This will be described below.

[0169] The wafer grid on the wafer W is deformed due to the process, and each individual shot is also slightly deformed by this process, but the deformation is considered to follow the deformation of the wafer grid. The variation components of the wafer grid can be divided into the following four independent variation components, and each variation component causes the following deformation of the shot. (1) Variation component of dx in the X-axis direction Change in magnification in the X-axis direction (2) Variation component of dx in the Y-axis direction Rotation with respect to the Y-axis (3) Variation component of dy in the X-axis direction Change in magnification in the Y-axis direction (4) Fluctuation component of dy in the Y-axis direction Rotation with respect to the X-axis

[0170] Therefore, in this embodiment, the fluctuation components of the above (1) to (4) are calculated, and based on the fluctuation components, the deformation of the shots on the wafer W is estimated.

[0171] By the way, there are roughly two methods for estimating the deformation of the shots, as shown below. (A) Deform the shot according to the values obtained by partially differentiating Equation (3) with respect to X and Y after determining the coefficients (undetermined coefficients). (B) Approximate the wafer grid with a first-order model equation and deform the shot according to the coefficients of the model equation. Here, for the wafer grid, the design position coordinates X and Y of each shot are substituted into Equation (3) after determining the coefficients (undetermined coefficients), and the correction amount (correction amounts dx and dy of the shot position coordinates) from the design values of the array of a plurality of shot regions on the wafer, that is, the deformation component of the wafer grid, is obtained, and it can be calculated using the correction amount and the design values of the shot position coordinates.

[0172] Hereinafter, the method of correcting the shape of the shot by the estimation method of (A) is called high-order partial differential correction, and the method of correcting the shape of the shot by the estimation method of (B) is called first-order approximation correction. Even for the same wafer grid, the deformed state of the shot is different when using the method of (A) and when using the method of (B).

[0173] In FIGS. 12(A) and 12(B), an example of the difference between high-order partial differential correction and first-order approximation correction is schematically shown. Here, for the sake of simplicity of explanation, it is assumed that the Y component dy = b6·X in the wafer grid 3 is the case. FIG. 12(A) shows three corrected shots by high-order partial differential correction. When performing high-order partial differential correction, the rotation of each shot with respect to the Y-axis is the partial differential of dy = b6·X 3 dy’ = 3b6·X 2It will come to follow this. In this case, among the three shots, the central shot has a deformation amount of 0. On the other hand, FIG. 12(B) shows the three corrected shots by the first-order approximation correction. In the first-order approximation correction, the alignment of the EGA method is performed again with a first-order model formula, and the shot shape is corrected using the first-order coefficient related to the rotation with respect to the Y-axis in the model formula. When this first-order approximation correction is performed, as shown in FIG. 12(B), among the three shots, the central shot is also linearly deformed, and as a whole, the deformation of each shot becomes uniform.

[0174] As shown in FIGS. 12(A) and 12(B), in the higher-order partial differential correction, the deformation of the shot is local along the wafer grid around the shot, whereas in the first-order approximation correction, the deformation of all the shots on the wafer W becomes uniform. For example, it may be possible to specify which method to select in the exposure recipe so that the user can appropriately select according to the required specifications of the semiconductor to be manufactured. Even when the deformation of such a shot is estimated, as described above, during the scanning exposure, the exposure control device 220 adjusts at least one of the relative scanning angle between the reticle stage RST and the wafer stage WST, the scanning speed ratio, the relative position of at least one of the reticle stage RST and the wafer stage WST with respect to the projection optical system, the imaging characteristics (aberration) of the projection optical system PL, and the wavelength of the illumination light (exposure light) IL so that the projection image of the pattern of the reticle R by the projection optical system PL is deformed according to the obtained shot shape (the shape of the shot obtained by estimating the deformation of the shot).

[0175] In the lithography system according to the present embodiment, when the measurement unit 40 of the measuring device 100 includes the above-described multi-point focus position detection system, the measuring device 100 may perform flatness measurement of the wafer W (also called focus mapping) together with wafer alignment measurement. In this case, by using the result of the flatness measurement, it is possible to perform focus and leveling control of the wafer W at the time of exposure without performing flatness measurement by the exposure device 200.

[0176] In the above embodiment, the target is assumed to be a 300 mm wafer, but it is not limited to this, and it may be a 450 mm wafer with a diameter of 450 mm. Since wafer alignment can be performed by the measuring device 100 separately from the exposure device 200, even for a 450 mm wafer, for example, full-point EGA measurement etc. can be performed without causing a reduction in the throughput of the exposure process.

[0177] Although not shown in the figure, in the lithography system 1000, the exposure device 200 and the C / D 300 may be connected in-line, and the measuring device 100 may be arranged on the side opposite to the exposure device 200 of the C / D 300. In this case, the measuring device 100 can be used for the same alignment measurement (hereinafter referred to as pre-measurement) as described above for a wafer before resist coating, for example. Alternatively, the measuring device 100 can also be used for the measurement of the positional deviation of the overlay misalignment measurement mark (overlay misalignment measurement) for a wafer after development, or can be used for both pre-measurement and overlay misalignment measurement.

[0178] In the above embodiment, for the sake of simplicity of explanation, it is assumed that either the A mode or the B mode is set as the measurement mode of the measuring device 100, but it is not limited to this. There are also provided a C mode for detecting two or more first numbers of wafer marks for all shots on all wafers in the lot, and for all wafers in the lot, for some shots, for example, for predetermined shots located at the peripheral part of the wafer, two or more second numbers of wafer marks are detected, and for the remaining shots, a mode (referred to as D mode) for detecting one wafer mark for each can be provided. Further, an E mode for selecting any one of the A mode, the C mode, and the D mode for the remaining wafers in the lot according to the detection result of the wafer marks for the first predetermined number of wafers in the lot may be provided.

[0179] In addition, as a measurement mode of the measuring device 100, for all the wafers in a lot, one or more wafer marks of some shots, for example, 90% or 80% of the number of shots, may be measured, or for the shots located at the center of the wafer, one or more wafer marks of every other shot may be measured.

[0180] In the measuring device 100 according to the above embodiment, the cases where the gratings RG1, RG2a, and RG2b each have the X-axis direction and the Y-axis direction as the periodic directions have been described. However, the present invention is not limited to this. As long as the grating portions (two-dimensional gratings) included in the first position measurement system 30 and the second position measurement system 50 each have two directions intersecting each other in the XY plane as the periodic directions.

[0181] In addition, the configuration of the measuring device 100 described in the above embodiment is merely an example. For example, the measuring device may have a stage (slider 10) movable with respect to a base member (surface plate 12), and may be configured to measure the position information of a plurality of marks on a substrate (wafer) held by the stage. Therefore, the measuring device does not necessarily have to include, for example, the first position measurement system 30 and the second position measurement system 50.

[0182] Also, it goes without saying that the configuration of the head portion 32 of the first position measurement system 30 and the arrangement of the detection points described in the above embodiment are merely examples. For example, the detection points of the mark detection system MDS and the detection center of the head portion 32 do not necessarily have to coincide in at least one of the X-axis direction and the Y-axis direction. Further, the arrangement of the head portion of the first measurement system 30 and the grating RG1 (lattice portion) may be reversed. That is, the head portion may be provided on the slider 10, and the lattice portion may be provided on the surface plate 12. Also, the first position measurement system 30 does not necessarily have to include the encoder system 33 and the laser interferometer system 35, and the first position measurement system 30 may be configured by the encoder system alone. The first position measurement system may be configured by an encoder system that irradiates a beam from the head portion to the grating RG1 of the slider 10 and receives the return beam (diffraction beam) from the grating to measure the position information of the slider 10 in the six-degree-of-freedom direction with respect to the surface plate 12. In this case, the configuration of the head of the head portion is not particularly limited. For example, a pair of XZ heads that irradiate detection beams at two points separated by the same distance in the X-axis direction with respect to a predetermined point on the grating RG1, and a pair of YZ heads that irradiate detection beams at two points separated by the same distance in the Y-axis direction with respect to the predetermined point may be provided, or a pair of three-dimensional heads that irradiate detection beams at two points separated in the X-axis direction of the grating RG1, and an XZ head or a YZ head that irradiates a detection beam at a point whose position in the Y-axis direction is different from the above two points may be provided. The first position measurement system 30 does not necessarily have to be able to measure the position information of the slider 10 in the six-degree-of-freedom direction with respect to the surface plate 12, and may be able to measure only the position information in the X, Y, and θz directions, for example. Also, the first position measurement system that measures the position information of the slider 10 with respect to the surface plate 12 may be disposed between the surface plate 12 and the slider 10.

[0183] Similarly, the configuration of the second position measurement system 50 described in the above embodiment is merely an example. For example, the head portions 52A and 52B may be fixed to the surface plate 12 side, and the scales 54A and 54B may be provided integrally with the mark detection system MDS. Further, although the case where the second position measurement system 50 includes a pair of head portions 52A and 52B has been illustrated, the present invention is not limited to this. The second position measurement system 50 may include only one head portion, or may include three or more head portions. In any case, it is desirable that the second position measurement system 50 can measure the positional relationship between the surface plate 12 and the mark detection system MDS in six degrees of freedom directions. However, the second position measurement system 50 does not necessarily have to measure all the positional relationships in six degrees of freedom directions.

[0184] In the above embodiment, the slider 10 is levitated and supported on the surface plate 12 by a plurality of air bearings 18, and the driving system 20 that drives the slider 10 in a non-contact state with respect to the surface plate 12 includes a first driving device 20A that drives the slider 10 in the X-axis direction and a second driving device 20B that drives the slider 10 in the Y-axis direction integrally with the first driving device 20A. However, the present invention is not limited to this, and as the driving system 20, a driving system configured to drive the slider 10 in six degrees of freedom directions on the surface plate 12 may be adopted. Such a driving system may be configured by a magnetic levitation type planar motor as an example. In such a case, the air bearings 18 become unnecessary. Note that the measuring device 100 may include a driving system that drives the surface plate 12 separately from the vibration isolation device 14.

[0185] In the lithography system 1000 of FIG. 1, only one measuring device 100 is provided. However, as in the following modification example, a plurality of measuring devices, for example, two measuring devices may be provided.

[0186] <<Modification Example>> FIG. 11 schematically shows the configuration of a lithography system 2000 according to a modified example. The lithography system 2000 includes an exposure apparatus 200, a C / D 300, and two measurement apparatuses 100a and 100b having the same configuration as the aforementioned measurement apparatus 100. The lithography system 2000 is installed in a clean room.

[0187] In the lithography system 2000, the two measurement apparatuses 100a and 100b are arranged in parallel between the exposure apparatus 200 and the C / D 300.

[0188] The exposure apparatus 200, the C / D 300, and the measurement apparatuses 100a and 100b included in the lithography system 2000 are arranged with their chambers adjacent to each other. The exposure control apparatus 220 of the exposure apparatus 200, the coating / development control apparatus 320 of the C / D 300, and the control apparatuses 60 of the measurement apparatuses 100a and 100b are connected to each other via a LAN 500 and communicate with each other. A storage apparatus 400 is also connected to the LAN.

[0189] In the lithography system 2000 according to this modified example, since the same operation sequence as that of the aforementioned lithography system 1000 can be set, the same effects as those of the lithography system 1000 can be obtained.

[0190] In addition, in the lithography system 2000, it is also possible to adopt a sequence in which both of the measurement apparatuses 100a and 100b are used for alignment measurement (hereinafter referred to as post-measurement) for the wafer after the aforementioned PB and the same alignment measurement (pre-measurement) for the wafer before resist coating. In this case, since the pre-measurement for a certain wafer is performed in parallel with the aforementioned series of wafer processes for a wafer different from that wafer, the throughput of the entire system is hardly reduced. However, for the first wafer, the time for pre-measurement cannot be overlapped with the time for the series of wafer processes.

[0191] By comparing the position measured in advance and the position measured after measurement for the same wafer mark on the same wafer, it is possible to obtain the position measurement error of the wafer mark due to resist coating. Therefore, when performing wafer alignment on the same wafer by the exposure apparatus 200, by correcting the position of the same wafer mark measured by the amount of the position measurement error of the wafer mark due to resist coating obtained above, it becomes possible to perform highly accurate EGA measurement in which the measurement error of the position of the wafer mark due to resist coating is canceled.

[0192] In this case, in both the pre-measurement and the post-measurement, the measurement result of the position of the wafer mark is affected by the holding state of the wafer holder. Therefore, it is desirable to adopt a sequence in which the same wafer is pre-measured and post-measured by the same measuring device 100a or 100b.

[0193] In the lithography system 2000, instead of the pre-measurement described above, the above-described overlay misalignment measurement may be performed on the wafer after development. In this case, one of the measuring devices 100a and 100b may be dedicated to the above-described post-measurement, and the other may be dedicated to the overlay misalignment measurement. Alternatively, for the same wafer, a sequence in which the post-measurement and the overlay misalignment measurement are performed by the same measuring device 100a or 100b may be adopted. In the latter case, for the same wafer, pre-measurement may be further performed by the same measuring device.

[0194] Although illustration is omitted, in the lithography system 2000, one of the measurement devices 100a and 100b, for example, the measurement device 100a, may be arranged on the side opposite to the exposure device 200 of the C / D 300. In this case, considering the flow of wafer transfer, the measurement device 100a is suitable for performing the above-described overlay deviation measurement on the wafer after development. If the individual differences in the holding state of the holders between the measurement devices 100a and 100b are hardly a problem, the measurement device 100a may be used for pre-measurement instead of overlay deviation measurement, or may be used for both overlay deviation measurement and pre-measurement.

[0195] In addition to this, in addition to the exposure device 200 and the C / D 300, three or more measurement devices 100 may be provided, all the devices may be connected in-line, and two of the three measurement devices 100 may be used for pre-measurement and post-measurement, and the remaining one measurement device may be dedicated to overlay deviation measurement. Each of the former two may be dedicated to pre-measurement and post-measurement, respectively.

[0196] In the above-described embodiments and modifications (hereinafter abbreviated as the above embodiments), the signal processing device 49 that processes the detection signals of the mark detection systems MDS included in the measurement devices 100, 100a, and 100b sends only the measurement results of the wafer marks with good waveforms of the detection signals obtained as the detection results of the mark detection systems MDS to the control device 60. As a result, the EGA calculation is performed by the control device 60 using the measurement results of those wafer marks. In the case where the EGA calculation is performed using a part of the position information of the wafer mark selected from a plurality of wafer marks with good waveforms of the detection signals obtained as the detection results by the mark detection system MDS by the exposure control device 220, it has been described. However, the present invention is not limited to this. The signal processing device 49 may send the measurement results of the remaining wafer marks excluding the wafer marks with poor waveforms of the detection signals obtained as the detection results of the mark detection system MDS to the control device 60. Further, the control device 60 may determine whether the detection signal obtained as the detection result by the mark detection system MDS is good or not instead of the signal processing device. Also in this case, the control device 60 performs the above-described EGA calculation using only the measurement results of the remaining wafer marks excluding the wafer marks for which the detection signal is determined to be good or the wafer marks for which the detection signal is determined to be bad. Then, it is desirable that the exposure control device 220 performs the above-described EGA calculation using the measurement results of a part of the wafer marks selected from the measurement results of the wafer marks used in the EGA calculation by the control device 60.

[0197] In the above-described embodiment, the case where the measurement devices 100, 100a, and 100b are arranged between the exposure apparatus 200 and the C / D 300 instead of the in-line interface unit has been exemplified. However, the present invention is not limited to this. The measurement device (100, 100a, 100b) may be a part of the exposure apparatus. For example, a measurement device may be installed in the loading unit of the exposure apparatus 200 where the wafer before exposure is loaded. Further, when the measurement device (100, 100a, 100b) is installed in the chamber of the exposure apparatus 200 as a part of the exposure apparatus, the measurement device may or may not include a chamber. Further, when the measurement device (100, 100a, 100b) is a part of the exposure apparatus, the measurement device may include a control device or may be controlled by the control device of the exposure apparatus without including a control device. In any case, the measurement device is in-line connected to the exposure apparatus.

[0198] In the above-described embodiment, the case where the substrate processing apparatus is the C / D has been described. However, the substrate processing apparatus only needs to be a device that is in-line connected to the exposure apparatus and the measurement device. It may be a coating device (coater) that applies a sensitizer (resist) onto the substrate (wafer), or a developing device (developer) that develops the substrate (wafer) after exposure. It may also be a coating device (coater) and a developing device (developer) that are respectively in-line connected to the exposure apparatus and the measurement device.

[0199] When the substrate processing apparatus is a coating device (coater), the measurement device can be used only for the post-measurement described above or for both the pre-measurement and the post-measurement. In this case, the wafer after exposure will be carried into a developing device that is not in-line connected to the exposure apparatus.

[0200] When the substrate processing apparatus is a developing device (developer), the measurement device can be used only for the post-measurement described above or for both the post-measurement and the overlay misalignment measurement. In this case, a wafer on which a resist has been previously applied at another location will be carried into the exposure apparatus.

[0201] In the above embodiment, the case where the exposure apparatus is a scanning stepper has been described. However, the exposure apparatus is not limited to this, and may be a static exposure apparatus such as a stepper, or may be a reduction projection exposure apparatus of a step-and-stitch method that synthesizes shot areas and shot areas. Further, for example, as disclosed in U.S. Patent No. 6,590,634, U.S. Patent No. 5,969,441, U.S. Patent No. 6,208,407, etc., the above embodiment can also be applied to a multi-stage exposure apparatus provided with a plurality of wafer stages. In addition, the exposure apparatus is not limited to a dry type exposure apparatus that exposes the wafer W without using the liquid (water) described above. For example, European Patent Application Publication No. 1420298, International Publication No. 2004 / 055803, International Publication No. 2004 / 057590, U.S. Patent Application Publication No. 2006 / 0231206, U.S. Patent Application Publication No. 2005 / 0280791, U.S. Patent No. 6,952,253, etc. It may be an immersion type exposure apparatus that exposes a substrate through a liquid described in the specification. Further, the exposure apparatus is not limited to an exposure apparatus for semiconductor manufacturing, and may be, for example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern to a rectangular glass plate.

[0202] Note that the disclosures of all gazettes, international publications, U.S. patent application publications, and U.S. patents related to the exposure apparatus and the like cited in the above embodiment are incorporated herein by reference and made part of the description of this specification.

[0203] A semiconductor device is manufactured through a lithography step of exposing a photosensitive object using a reticle (mask) on which a pattern is formed by an exposure apparatus constituting the lithography system according to the above embodiment, and developing the exposed photosensitive object. In this case, high-density devices can be manufactured with good yield.

[0204] Note that in addition to the lithography step, the manufacturing process of a semiconductor device may include steps for designing the functions and performance of the device, steps for fabricating a reticle (mask) based on this design step, a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like.

Description of Reference Numerals

[0205] 10…Slider, 12…Surface plate, 14…Vibration isolation device, 16…Base frame, 18…Air bearing, 20…Drive system, 20A…First drive device, 20B…Second drive device, 22a, 22b…Movables, 23a, 23b…Movables, 24…Movable stage, 25a, 25b…Stators, 26a, 26b…Stators, 28A, 28B…X-axis linear motors, 29A, 29B…Y-axis linear motors, 30…First position measurement system, 32…Head unit, 33…Encoder system, 35a~35d…Laser interferometers, 37x…X head, 37ya, 37yb…Y heads, 40…Measurement unit, 48…Vibration isolation device, 50…Second position measurement system, 52A, 52B…Head units, 58X1, 58X2…XZ heads, 58Y1, 58Y2…YZ heads, 60…Control device, 100…Measurement device, 100a, 100b…Measurement devices, 200…Exposure device, 300…C / D, 330…Temperature control unit, 1000…Lithography system, MDS…Mark detection system, RG1…Gratings, RG2a, RG2b…Gratings, W…Wafer, WST…Wafer stage.

Claims

1. A measuring device for measuring the positions of a plurality of marks formed on a substrate, comprising: a slider that holds the substrate and is movable on a moving plane; a mark detection system that detects the marks formed on the substrate held by the slider; a position measurement system that acquires position information and inclination information of the slider; and mark position information is acquired based on the detection result of the marks detected by the mark detection system and the position information of the slider acquired by the position measurement system, and the measuring device corrects the mark position information using the inclination information.

2. The position measurement system includes a first grating portion irradiated with a plurality of measurement beams, and a first head portion that irradiates the measurement beams to the first grating portion and receives the return beams from the first grating portion, wherein one of the first grating portion and the first head portion is provided on the slider, and the inclination information is an inclination of the slider with respect to the moving plane, which is acquired based on the plurality of return beams. The measuring device according to claim 1.

3. The slider is movable in a first direction along the moving plane, a second direction along the moving plane and intersecting the first direction, and a third direction intersecting the first direction and the second direction, the inclination information includes a rotation amount around the first direction and a rotation amount around the second direction, and the mark position information is corrected based on the inclination information of the slider and the distance between the surface on which the marks of the substrate are formed and the first grating portion. The measuring device according to claim 2.

4. further comprising a reference member, wherein the position measurement system includes a first position measurement system having the first grating portion and the first head portion and acquiring relative position information of the slider with respect to the reference member, and a second position measurement system acquiring relative position information of the mark detection system with respect to the reference member. The measuring device according to claim 2 or 3.

5. the reference member is provided with the other of the first grating portion and the first head portion, and one of a second grating portion and a second head portion included in the second position measurement system, and the mark detection system is provided with the other of the second grating portion and the second head portion. The measuring device according to claim 4.

6. The reference member is a surface plate having an upper surface portion that defines the moving plane. The measuring device according to claim 4 or 5.

7. a height detection system that detects the height of the surface of the substrate A drive system that adjusts the position of the slider in the third direction, the amount of rotation around the first direction, and the amount of rotation around the second direction based on the detection result of the height detection system. The measuring device according to claim 3, wherein the mark position information is corrected using the inclination information of the adjusted slider acquired by the position measuring system. **Claim 8** The measuring device according to claim 7, wherein height distribution information of the substrate is acquired from the detection result of the height detection system and the position information of the slider acquired by the position measuring system. **Claim 9** The position measuring system includes a first measuring system that measures the position of the slider in the third direction at at least three locations, and a second measuring system that measures the positions of the slider in the second direction and the third direction. The measuring device according to claim 3. **Claim 10** The first measuring system is a laser interferometer that measures the position in the third direction by reflecting the measurement beam from the first grating section. The measuring device according to claim 9, wherein the second measuring system is an encoder that measures the positions in the second direction and the third direction by diffracting the measurement beam from the first grating section. **Claim 11** The first grating section has a reflection layer that reflects the measurement beam of the first measuring system and a grating layer that diffracts the measurement beam of the second measuring system. The measuring device according to claim 10. **Claim 12** A mark position measuring method for measuring the positions of a plurality of marks formed on a substrate, comprising: detecting the mark formed on the substrate held by a slider movable on a moving plane; acquiring position information and inclination information of the slider; acquiring mark position information based on the detection result of the mark and the position information of the slider; A mark position measuring method for correcting the mark position information using the inclination information. **Claim 13** A measuring device according to any one of claims 1 to 11, and an exposure device for exposing the substrate, wherein the exposure device is a substrate processing system that exposes the substrate based on the position information of the mark measured and corrected by the measuring device. **Claim 14** Acquiring position information of a plurality of marks formed on a substrate by the mark position measuring method according to claim 12, and An exposure method for exposing the substrate based on the acquired position information of the plurality of marks.

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