Measurement device, lithography system and exposure device, and management method, superposition measurement method and device manufacturing method

Abstract

A measuring device (100) comprises a slider (10) capable of moving parallel to the XY plane while holding a substrate (W), a driving system for driving the slider, a position measuring system (30) capable of measuring position information in at least three degrees of freedom including absolute position coordinates of the slider by irradiating a plurality of beams from a head portion (32) onto a measuring surface having a grid portion (RG1) formed on the slider and receiving a return beam from each of the plurality of beams on the measuring surface, a mark detection system (MDS) for detecting marks on the substrate, and a control device that detects a plurality of marks on the substrate using the mark detection system while controlling the driving of the slider, and obtains the absolute position coordinates of each mark based on the detection result of each mark and the measurement information of the position measuring system at the time of detection.

Description

Technology Field

[0001] The present invention relates to a measuring device, a lithography system and an exposure device, and to a management method, an overlapping measuring method and a method for manufacturing a device, and in particular to a measuring device for measuring position information of a plurality of marks formed on a substrate, and an exposure device having a substrate stage on which the measurement of position information of a plurality of marks by the measuring device is completed, a lithography system having said measuring device, an exposure device having said measuring device, a management method for managing a variation in the arrangement of a plurality of partitioned regions on a substrate, an overlapping measuring method having the substrate as a measurement target, and a method for manufacturing a device using said lithography system or exposure device. Background Technology

[0002] In a lithography process for manufacturing semiconductor devices, multilayer circuit patterns are formed by overlapping on a substrate such as a wafer or a glass plate (hereinafter collectively referred to as a wafer). However, if the precision of overlap between layers is poor, the semiconductor device cannot exhibit the desired circuit characteristics and, in some cases, may become a defective product. Therefore, a mark (alignment mark) is typically formed in advance on each of the multiple shot regions on the wafer, and the position (coordinate value) of the mark on the stage coordinate system of the exposure device is detected. Subsequently, wafer alignment is performed to align a single shot region on the wafer with respect to the pattern based on this mark position information and the already known position information of a newly formed pattern (e.g., a reticle pattern).

[0003] As a wafer alignment method, Enhanced Global Alignment (EGA) has become the mainstream approach in balance with throughput, as it detects alignment marks in only a few short regions (also called sample short regions or alignment short regions) on the wafer and calculates the arrangement of short regions on the wafer using statistical methods.

[0004] However, in a lithography process, when superimposing exposure is performed on a wafer, the wafer that has undergone process treatments such as resist coating, development, etching, CVD (chemical vapor deposition), and CMP (chemical mechanical polishing) may have deformation in the arrangement of the shot regions of the entire layer due to the process, and such deformation can be a factor in the reduction of superposition precision. Taking this into account, recent exposure devices have a grid correction function that corrects not only the primary component of wafer deformation but also the non-linear component of the shot arrangement caused by the process (see, for example, Patent Document 1).

[0005] Conventionally, for example, the management of wafer grid variations caused by a device is performed by overlapping exposure using a dedicated reticle for grid management on a reference wafer marked with a mark. Here, a wafer grid refers to a grid formed by connecting the centers of shot areas on a wafer arranged according to a shot map (data regarding the arrangement of shot areas formed on a wafer). In this specification, the wafer grid is abbreviated as "grid" or described as "arrangement of shot areas (or shots)."

[0006] Ideally, grid management should be performed for every short map, but since this would require countless reticles and wafers, a reference wafer and the aforementioned dedicated reticles are used.

[0007] However, since the marks that can be engraved on a reference wafer are finite and discrete no matter how finely they are assigned, it is difficult to manage the wafer grid using the product shot map of the user of the exposure device itself. Furthermore, grid management using a reference wafer is typically based on the following premises (assumptions) and involves a kind of compromise.

[0008] a. Grid error is coordinate-dependent, and identical locations have the same error. If the position of a mark is measured and the grid error is corrected near that point, the error is considered to be small.

[0009] b. Errors such as scan speed or scan acceleration do not cause grid error. Even if grid error were to occur, since the error does not change with every scan, a single adjustment is sufficient, and regular maintenance is not required. Prior art literature

[0010] Specification of U.S. Application Publication No. 2002 / 0042664 means of solving the problem

[0011] According to a first embodiment, a measuring device for measuring position information of a plurality of marks formed on a substrate is provided, comprising: a stage that moves while holding the substrate; a driving system that drives the stage; an absolute position measuring system in which one of a measuring surface having a grid portion and a head portion that irradiates a beam onto the measuring surface is formed on the stage, and which can acquire position information of the stage by receiving a return beam from the measuring surface of the beam irradiating the beam from the head portion onto the measuring surface; a mark detection system that detects a mark formed on the substrate; and a control device that controls the driving of the stage by the driving system, detects each of the plurality of marks formed on the substrate using the mark detection system, and obtains the absolute position coordinates of each of the plurality of marks based on the detection result of each of the plurality of marks and the position information of the stage obtained using the absolute position measuring system at the time of detection of each of the plurality of marks.

[0012] According to a second embodiment, a lithography system is provided having a measuring device related to a first embodiment and a substrate stage on which the substrate, on which the measurement of position information of a plurality of marks by the measuring device is completed, is placed, and an exposure device that performs alignment measurement for measuring position information of a selected portion of a plurality of marks on the substrate and exposure of the substrate with an energy beam for exposure of the substrate with respect to the substrate placed on the substrate stage.

[0013] According to a third embodiment, a method for manufacturing a device is provided, comprising exposing a substrate using a lithography system related to a second embodiment and developing the exposed substrate.

[0014] According to the fourth embodiment, an exposure device is provided that includes a measuring device related to the first embodiment and exposes a substrate, on which position information of a plurality of marks has been acquired using the measuring device, to an energy beam.

[0015] According to the fifth embodiment, a method for manufacturing a device is provided, comprising exposing a substrate using an exposure device related to the fourth embodiment and developing the exposed substrate.

[0016] According to a sixth embodiment, a management method for managing a variation of an arrangement of a plurality of partitioned regions arranged in a matrix on a substrate is provided, comprising: sequentially transferring a pattern and a mark formed on a mask onto a substrate by an exposure device, and forming a plurality of partitioned regions together with the mark on the substrate; mounting the substrate having the plurality of partitioned regions formed thereon onto a stage that moves within a predetermined plane, and positioning information of the stage by irradiating a beam through a measuring surface having a grid portion formed on the stage with a head portion interposed therein, and receiving a return beam from the measuring surface of the beam, and measuring position information including absolute position coordinates within the predetermined plane of the stage using an absolute position measuring system, and detecting each of the plurality of marks corresponding to each of the plurality of partitioned regions on the substrate using a mark detection system, and obtaining the absolute position coordinates within the predetermined plane of each of the plurality of marks corresponding to each of the plurality of partitioned regions on the substrate based on the detection result of each of the plurality of marks and the measurement information of the absolute position measuring system at the time of detection of each of the plurality of marks, and obtaining arrangement information of the plurality of partitioned regions based on the obtained absolute position coordinates of the plurality of marks.

[0017] According to the seventh embodiment, a superposition measurement method is used to measure a substrate in which a set of second mark images corresponding to a first mark image is formed in a plurality of predetermined positional relationships by exposure of a first layer and exposure of a second layer having the first layer as an underlayer, wherein the substrate to be measured is mounted on a stage having a measurement surface having a grid portion and one side of a head portion that irradiates a beam onto the measurement surface, and the position information of the stage is measured using a position measurement system capable of measuring position information in at least three degrees of freedom directions including absolute position coordinates within the predetermined plane of the stage by irradiating a plurality of beams onto the measurement surface with the head portion interposed therein and receiving the return beam from the measurement surface of each of the plurality of beams, while detecting the first mark image and the second mark image of the plurality of sets on the substrate using a mark detection system, and based on the detection results of each of the first mark image and the second mark image of the plurality of sets and the measurement information of the position measurement system at the time of detection of each mark image, the first mark image of the plurality of sets on the substrate and the A method for measuring overlap is provided, comprising obtaining the absolute position coordinates within a predetermined plane for each of the two mark images, and obtaining an overlap error based on the absolute position coordinates of the first mark image and the second mark image that form a set with each other. Brief explanation of the drawing

[0018] FIG. 1 is a perspective view schematically showing the configuration of a measuring device related to a first embodiment. FIG. 2(A) is a partially omitted front view (viewed from the -Y direction) of the measuring device of FIG. 1, and FIG. 2(B) is a partially omitted cross-sectional view of the measuring device taken in the XZ plane passing through the optical axis (AX1) of the mark detector system. FIG. 3 is a cross-sectional view of a measuring device with some parts omitted, taken in the YZ plane passing through the optical axis (AX1) of the mark detector. FIG. 4(A) is a perspective view showing the head portion of the first position measuring system, and FIG. 4(B) is a plan view (viewed from the +Z direction) of the head portion of the first position measuring system. Figure 5 is a diagram illustrating the configuration of a second position measurement system. FIG. 6 is a block diagram showing the input-output relationship of a control device that primarily constitutes the control system of a measuring device related to the first embodiment. Figure 7 is a flowchart corresponding to the processing algorithm of the control device when processing one lot of wafers. FIG. 8 is a diagram schematically showing the overall configuration of a lithography system related to a second embodiment. FIG. 9 is a schematic diagram showing the configuration of the exposure device shown in FIG. 8. FIG. 10 is a block diagram showing the input-output relationship of an exposure control device equipped with an exposure device. FIG. 11 is a diagram schematically showing the flow of processing when a method for managing a wafer grid of an exposure device using a measuring device (100) is applied to a lithography system (1000). FIG. 12 is a diagram schematically showing the flow of processing when an overlapping measurement method using a measuring device (100) is applied to a lithography system (1000). FIG. 13 is a diagram schematically showing the overall configuration of a lithography system related to a modified example. Specific details for implementing the invention

[0019] 《First Embodiment》

[0020] Hereinafter, a first embodiment is described based on FIGS. 1 to 7. FIG. 1 schematically shows the configuration of a measuring device (100) related to the first embodiment in a perspective view. In addition, the measuring device (100) shown in FIG. 1 is actually composed of a chamber and a component housed inside the chamber, but in this embodiment, the description regarding the chamber is omitted. In this embodiment, a mark detection system (MDS) is formed as described below, and below, the direction of the optical axis (AX1) of the mark detection system (MDS) is set as the Z-axis direction, and the direction in which the movable stage described below moves in a long stroke within a plane orthogonal to this is set as the Y-axis direction, the direction orthogonal to the Z-axis and Y-axis is set as the X-axis direction, and the directions of rotation (inclination) around the X-axis, Y-axis, and Z-axis are set as θx, θy, and θz directions, respectively, for the description. Here, the mark detection system (MDS) has an L-shaped external shape when viewed from the side (e.g., when viewed from the +X direction), and a cylindrical barrel portion (41) is formed at the bottom (tip) of the mark detection system (MDS). Inside the barrel portion (41), an optical system (refractive optical system) consisting of a plurality of lens elements having an 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 barrel portion (41) is referred to as the optical axis (AX1) of the mark detection system (MDS).

[0021] In FIG. 2(A), a front view (viewed from the -Y direction) of the measuring device (100) of FIG. 1 is shown with some omissions, and in FIG. 2(B), a cross-sectional view of the measuring device (100) taken in the XZ plane passing through the optical axis (AX1) is shown with some omissions. Also, in FIG. 3, a cross-sectional view of the measuring device (100) taken in the YZ plane passing through the optical axis (AX1) is shown with some omissions.

[0022] As shown in FIG. 1, the measuring device (100) comprises a fixed plate (12) having an upper surface nearly parallel to the XY plane orthogonal to the optical axis (AX1), a wafer slider (hereinafter abbreviated as slider) (10) disposed on the fixed plate (12) and capable of holding a wafer (W) and moving in a predetermined stroke in the X-axis and Y-axis directions relative to the fixed plate (12), and also capable of micro-movement (micro-displacement) in the Z-axis, θx, θy, and θz directions, a driving system (20) for driving the slider (10) (not shown in FIG. 1, see FIG. 6), and a first position measuring system (30) for measuring position information of the slider (10) in each direction of the X-axis, Y-axis, Z-axis, θx, θy, and θz relative to the fixed plate (12) (hereinafter referred to as 6 degrees of freedom directions) (not shown in FIG. 1). (Omitted, see FIG. 3 and FIG. 6) and a measuring unit (40) having a mark detection system (MDS) that detects a mark on a wafer (W) mounted (held) on a slider (10), a second position measuring system (50) that measures relative position information between the mark detection system (MDS) (measuring unit (40)) and the platen (12) (not shown in FIG. 1, see FIG. 6), and a control device (60) that controls the driving of the slider (10) by a driving system (20), acquires measurement information by the first position measuring system (30) and measurement information by the second position measuring system (50), and obtains position information of a plurality of marks on the wafer (W) held on the slider (10) using the mark detection system (MDS) (not shown in FIG. 1, see FIG. 6).

[0023] The platen (12) is made of a rectangular (or square) member when viewed from a flat plane, and its upper surface is finished to have a very high degree of flatness and a guide surface is formed for the movement of the slider (10). As the material for the platen (12), a material with a low thermal expansion rate, also called a zero expansion material, such as an Invar-type alloy, ultra-low expansion cast steel, or ultra-low expansion glass ceramics is used.

[0024] In the platen (12), a cut-out void (12a) is formed with a bottom opening at a total of three points: one point in the center of the X-axis direction of the -Y side surface, and one point each at both ends of the X-axis direction of the +Y side surface. In FIG. 1, among the three voids (12a), the void (12a) formed on the -Y side surface is shown. A vibration damping device (14) is disposed inside each void (12a). The platen (12) is supported at three points by three vibration damping devices (14) so ​​that the top surface is nearly parallel to the XY plane when viewed from a plane installed on the floor (F), on the top surface of a rectangular base frame (16) that is parallel to the XY plane. Additionally, the number of vibration damping devices (14) is not limited to three.

[0025] As shown in FIG. 3, the slider (10) is mounted with one air hydrostatic bearing (air bearing) (18) at each of the four corners of the bottom surface, for a total of four, with each bearing surface being nearly identical to the bottom surface of the slider (10). The slider (10) is supported by the hydrostatic pressure (pressure within the gap) between the bearing surface of the pressurized air ejected from these four air bearings (18) toward the platen (12) and the upper surface (guide surface) of the platen (12), so that the slider (10) is supported by floating above the upper surface of the platen (12) with a predetermined clearance (gap), for example, a clearance of about a few micrometers. In this embodiment, the slider (10) is made of zero-expansion glass (e.g., Schott's Zerodur, etc.), which is a type of zero-expansion material.

[0026] On the upper part of the slider (10), a circular concave portion (10a) of a predetermined depth is formed when viewed from a flat plane with an inner diameter slightly larger than the diameter of the wafer (W), and a wafer holder (WH) with a diameter almost identical to the diameter of the wafer (W) is disposed inside the concave portion (10a). As the wafer holder (WH), a vacuum chuck, an electrostatic chuck, or a mechanical chuck can be used, but as an example, a pin chuck type vacuum chuck is used. The wafer (W) is held by suction by the wafer holder (WH) in a state where its upper surface is almost identical to the upper surface of the slider (10). A plurality of suction ports are formed in the wafer holder (WH), and these plurality of suction ports are connected to a vacuum pump (11) (see FIG. 6) via a vacuum piping system that is not shown. And, the on / off of the vacuum pump (11) is controlled by the control device (60). Also, either or both of the slider (10) and the wafer holder (WH) may be referred to as the "first substrate holding member."

[0027] Additionally, the slider (10) has an up-and-down movement member (not shown) formed therein that moves up and down through, for example, three circular openings formed in the wafer holder (WH) and works in cooperation with a wafer transport system (70) (not shown in FIG. 1, see FIG. 6) to load a wafer onto the wafer holder (WH) and unload the wafer from the wafer holder (WH). A driving device (13) that drives the up-and-down movement member is controlled by a control device (60) (see FIG. 6).

[0028] In this embodiment, as a wafer holder (WH), a size capable of adsorbing and holding a 300 mm wafer with a diameter of 300 mm is used as an example. Additionally, if the wafer transport system (70) has a non-contact holding member, such as a Bernoulli chuck, that sucks and holds the wafer on the wafer holder (WH) from above without contact, there is no need to form an up-and-down movement member on the slider (10), nor is there a need to form a circular opening for the up-and-down movement member on the wafer holder (WH).

[0029] As shown in FIG. 2(B) and FIG. 3, a two-dimensional grating (hereinafter simply called grating) (RG1) is arranged horizontally (parallel to the surface of the wafer (W)) in an area larger than the wafer (W) on the lower surface of the slider (10). The grating (RG1) includes a reflective diffraction grating (X diffraction grating) with the X-axis direction as the periodic direction and a reflective diffraction grating (Y diffraction grating) with 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.

[0030] The vibration isolation device (14) is an active vibration isolation system (so-called AVIS (Active Vibration Isolation System)) and is equipped with an accelerometer, a displacement sensor (e.g., a capacitive sensor, etc.), an actuator (e.g., a voice coil motor, etc.), and an air mount that functions as an air damper. The vibration isolation device (14) can dampen relatively high-frequency vibrations by the air mount (air damper) and can also dampen vibrations (vibration control) by the actuator. Therefore, the vibration isolation device (14) can avoid the transmission of vibrations between the base plate (12) and the base frame (16). In addition, a hydraulic damper may be used instead of the air mount (air damper).

[0031] Here, the reason an actuator is formed in addition to the air mount is that, since the internal pressure of the gas inside the gas chamber of the air mount is high, the control response can only be secured at about 20 Hz; therefore, when high-response control is required, it is necessary to control the actuator according to the output of an accelerometer, etc., which is not shown. However, fine vibrations such as floor vibration are dampened by the air mount.

[0032] The upper surface of the vibration damping device (14) is connected to the platen (12). It is possible to supply gas (e.g., compressed air) to the air mount through a gas supply port (not shown in the illustration), and the air mount extends and retracts in the Z-axis direction by a predetermined stroke (e.g., about 1 mm) according to the amount of gas filled inside (change in the pressure of the compressed air). Because of this, by using the air mounts of each of the three vibration damping devices (14) to individually move three points of the platen (12) up and down from below, the positions of the platen (12) and the slider (10) supported on it can be arbitrarily adjusted in the Z-axis direction, the θx direction, and the θy direction, respectively. In addition, the actuator of the vibration damping device (14) can drive the platen (12) not only in the Z-axis direction but also in the X-axis direction and the Y-axis direction. Furthermore, the amount of driving in the X-axis direction and the Y-axis direction is smaller than the amount of driving in the Z-axis direction. Three vibration damping devices (14) are connected to a control device (60) (see FIG. 6). Additionally, each of the three vibration damping devices (14) may be equipped with an actuator capable of moving the platen (12) in, for example, six degrees of freedom directions, not limited to the X-axis, Y-axis, and Z-axis directions. The control device (60) always controls the actuators of the three vibration damping devices (14) in real time so that the position of the platen (12), to which the head part (32) of the first position measurement system (30) described later is fixed, maintains a desired positional relationship with the mark detection system (MDS), based on the relative position information of the mark detection system (MDS) (measurement unit (40)) and the platen (12) measured by the second position measurement system (50). In addition, each of the three vibration damping devices (14) may be fed forward controlled.For example, the control device (60) may feed-forward control each of the three vibration damping devices (14) based on the measurement information of the first position measurement system (30). Additionally, the control of the vibration damping devices (14) by the control device (60) will be described further later.

[0033] The driving system (20) includes a first driving device (20A) that drives the slider (10) in the X-axis direction, as shown in FIG. 6, and a second driving device (20B) that drives the slider (10) in the Y-axis direction in conjunction with the first driving device (20A).

[0034] As can be seen from FIGS. 1 and FIGS. 3, on the side of the slider (10) on the -Y side, a pair of movables (22a) made of a magnet unit (or coil unit) and shaped like an inverted L when viewed from the side are fixed at predetermined intervals in the X-axis direction. On the side of the slider (10) on the +Y side, as shown in FIG. 3, a pair of movables (22b) made of a magnet unit (or coil unit) (where the movables (22b) on the +X side are omitted from the drawing) are fixed at predetermined intervals in the X-axis direction. The pair of movables (22a) and the pair of movables (22b) are arranged symmetrically on the left and right sides, but are configured identically to each other.

[0035] As shown in FIGS. 1 to 3, the movable members (22a, 22b) are arranged at a predetermined distance in the Y-axis direction, forming part of the movable stage (24) on a rectangular frame when viewed from a planar view, and are supported non-contactually on an upper surface substantially parallel to the XY plane of a pair of plate members (24a, 24b) that extend in the X-axis direction. That is, an air bearing (not shown) is formed on the lower surface of the movable members (22a, 22b) (the surface facing each of the plate members (24a, 24b)), and the movable members (22a, 22b) are supported non-contactually from below by the movable stage (24) by the buoyancy force (static pressure of pressurized air) generated by these air bearings against the plate members (24a, 24b). In addition, the self-weight of the fixed slider (10), with each pair of actuators (22a, 22b) attached, is supported by the buoyancy force generated by the four air bearings (18) against the platen (12), as described above.

[0036] On the upper surface of each of the pair of plate members (24a, 24b), as shown in FIGS. 1 to 3, a stator (26a, 26b) consisting of a coil unit (or magnet unit) is disposed in an area excluding both ends in the X-axis direction.

[0037] By the electronic interaction between a pair of movers (22a) and a stator (26a), a driving force (electromagnetic force) that drives a pair of movers (22a) in the X-axis direction and a driving force (electromagnetic force) that drives a pair of movers (22b) in the Y-axis direction is generated, and by the electronic interaction between a pair of movers (22b) and a stator (26b), a driving force (electromagnetic force) that drives a pair of movers (22b) in the X-axis direction and a driving force (electromagnetic force) that drives a pair of movers (22b) in the Y-axis direction is generated. That is, an XY linear motor (28A) is configured to generate driving force in the X-axis direction and Y-axis direction by means of a pair of actuators (22a) and a stator (26a), and an XY linear motor (28B) is configured to generate driving force in the X-axis direction and Y-axis direction by means of a pair of actuators (22b) and a stator (26b), and a first driving device (20A) is configured to drive the slider (10) with a predetermined stroke in the X-axis direction and drive it with a small force in the Y-axis direction by means of the XY linear motor (28A) and the XY linear motor (28B) (see FIG. 6). The first driving device (20A) can drive the slider (10) in the θz direction by making the magnitude of the driving force in the X-axis direction generated by the XY linear motor (28A) and the XY linear motor (28B) different. The first driving device (20A) is controlled by a control device (60) (see FIG. 6). In this embodiment, the first driving device (20A) and the second driving device described later form a coarse-motion driving system that drives the slider (10) in the Y-axis direction. In this relationship, the first driving device (20A) generates driving force in the Y-axis direction as well as driving force in the X-axis direction, but the first driving device (20A) does not necessarily need to generate driving force in the Y-axis direction.

[0038] The movable stage (24) has a pair of plate members (24a, 24b) and a pair of connecting members (24c, 24d) arranged at a predetermined distance apart in the X-axis direction and each extending in the Y-axis direction. At both ends of the connecting members (24c, 24d) in the Y-axis direction, a step is formed. Then, with the longitudinal end and the other end of the plate member (24a) placed on the -Y-side end of each connecting member (24c, 24d), the connecting members (24c, 24d) and the plate member (24a) are integrated. In addition, with the longitudinal end and the other end of the plate member (24b) placed on the +Y side end of each connecting member (24c, 24d), the connecting member (24c, 24d) and the plate member (24b) are integrated (see FIG. 2(B)). That is, in this way, a pair of plate members (24a, 24b) are connected by a pair of connecting members (24c, 24d), and a movable stage (24) on a rectangular frame is formed.

[0039] As shown in FIGS. 1 and 2(A), a pair of linear guides (27a, 27b) extending in the Y-axis direction are fixed near both ends in the X-axis direction of the upper surface of the base frame (16). Inside one linear guide (27a) located on the +X side, a stator (25a) of a Y-axis linear motor (29A) (see FIG. 2(B)) consisting of a coil unit (or magnet unit) extending nearly the entire length in the Y-axis direction is housed near the upper surface and the surface on the -X side. Opposite the upper surface and the surface on the -X side of the linear guide (27a), a movable member (23a) consisting of a magnet unit (or coil unit) with an L-shaped cross section and constituting the Y-axis linear motor (29A) together with the stator (25a) is disposed. Air bearings that spray pressurized air are fixed to the lower surface and the +X side surface of the movable member (23a), which respectively face the upper surface and the -X side surface of the linear guide (27a). In particular, a vacuum preload type air bearing is used as the air bearing fixed to the +X side surface of the movable member (23a). This vacuum preload type air bearing maintains the clearance (gap) in the X-axis direction between the movable member (23a) and the linear guide (27a) at a constant value by balancing the static pressure of the pressurized air between the bearing surface and the -X side surface of the linear guide (27a) and the vacuum preload force.

[0040] On the upper surface of the movable member (23a), a plurality of X guides (19), each consisting of, for example, two rectangular members, are fixed at a predetermined distance in the Y-axis direction. On each of the two X guides (19), a slide member (21) with an inverted U-shaped cross section, which together with the X guide (19) constitutes a 1-axis guide device, is non-contactfully engaged. On the three surfaces of the slide member (21) facing the X guide (19), air bearings are formed.

[0041] Two slide members (21) are each fixed to the lower surface (-Z side surface) of the connecting member (24c), as shown in FIG. 1.

[0042] The other linear guide (27b) located on the -X side houses the stator (25b) of the Y-axis linear motor (29B), which is made of a coil unit (or magnet unit) inside, and is symmetrical to the left and right but configured in the same way as the linear guide (27a) (see FIG. 2(B)). Opposite the upper surface of the linear guide (27b) and the surface on the +X side, the movable member (23b) is arranged to form the Y-axis linear motor (29B) together with the stator (25b), and is made of a magnet unit (or coil unit) with an L-shaped cross section identical to the movable member (23a), which is symmetrical to the left and right. Air bearings are respectively fixed to the upper surface and the +X side surface of the linear guide (27b), and to the lower surface and the -X side surface of the movable member (23b). In particular, a vacuum preloaded air bearing is used as the air bearing fixed to the -X side surface of the movable member (23b). By this vacuum preloaded air bearing, the clearance (gap) in the X-axis direction between the movable member (23b) and the linear guide (27b) is maintained at a constant value.

[0043] Between the upper surface of the movable member (23b) and the lower surface of the connecting member (24d), two 1-axis guide devices are formed, each consisting of an X guide (19) and a slide member (21) that engages with the X guide (19) in a non-contact manner, just as in the previous example.

[0044] The movable stage (24) is supported from below by movable members (23a, 23b) via 2 1-axis guide devices each on the +X side and -X side (total 4), and is movable in the X-axis direction on the movable members (23a, 23b). Because of this, when the slider (10) is driven in the X-axis direction by the first driving device (20A) described above, the reaction force of the driving force acts on the movable stage (24) on which the stator (26a, 26b) is formed, and the movable stage (24) moves in the opposite direction to the slider (10) according to the law of conservation of momentum. That is, the occurrence of vibration caused by the reaction force of the driving force in the X-axis direction relative 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 necessary to make the movable stage (24) function as a counter mass. Also, since the slider (10) only moves slightly in the Y-axis direction relative to the movable stage (24), it is not specifically formed, but a counter mass may be formed to prevent (or effectively suppress) the occurrence of vibration caused by the driving force driving the slider (10) in the Y-axis direction relative to the movable stage (24).

[0045] The Y-axis linear motor (29A) generates a driving force (electromagnetic force) that drives the actuator (23a) in the Y-axis direction by means of an electromagnetic interaction between the actuator (23a) and the stator (25a), and the Y-axis linear motor (29B) generates a driving force (electromagnetic force) that drives the actuator (23b) in the Y-axis direction by means of an electromagnetic interaction between the actuator (23b) and the stator (25b).

[0046] The driving force in the Y-axis direction generated by the Y-axis linear motors (29A, 29B) acts on the movable stage (24) through two 1-axis guide devices on the +X side and -X side, respectively. As a result, the slider (10) is driven in the Y-axis direction integrally with the movable stage (24). That is, in this embodiment, a second driving device (20B) (see FIG. 6) that drives the slider (10) in the Y-axis direction is configured by the movable stage (24), four 1-axis guide devices, and one pair of Y-axis linear motors (29A, 29B).

[0047] In this embodiment, a pair of Y-axis linear motors (29A, 29B) are physically separated from the platen (12) and are also vibrationally separated by three vibration damping devices (14). Additionally, linear guides (27a, 27b), each having a stator (25a, 25b) formed therein for a pair of Y-axis linear motors (29A, 29B), may be configured to be movable in the Y-axis direction relative to the base frame (16) and may function as a counter mass when the slider (10) is driven in the Y-axis direction.

[0048] As shown in FIG. 1, the measuring unit (40) has a unit body (42) having a cut-out opening (42a) formed on the -Y side with the bottom open, a aforementioned mark detection system (MDS) connected to the unit body (42) with the base inserted into the opening (42a), and a connection mechanism (43) connecting the tip of the mark detection system (MDS) to the unit body (42).

[0049] The connecting mechanism (43) includes a support plate (44) that supports the barrel portion (41) on the back side (+Y side) via a mounting member that is not shown, and a pair of support arms (45a, 45b) that support the support plate (44) at one end and have the other end fixed to the bottom surface of the unit body (42).

[0050] In this embodiment, corresponding to the fact that a sensitizing agent (resist) is applied to the upper surface of the wafer held on the slider (10), a detection beam of a wavelength that does not sensitize the resist is used as a mark detection system (MDS). As a mark detection system (MDS), for example, a broadband detection beam that does not sensitize the resist applied on the wafer is irradiated onto a 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 indicator (indicator pattern on an indicator plate formed internally) are captured using an imaging element (CCD, etc.), and an image of the indicator (indicator pattern on an indicator plate formed internally) are captured, and the captured signals are output. The captured signals from the mark detection system (MDS) are supplied to a control device (60) through a signal processing device (49) (not shown in FIG. 1, see FIG. 6) (see FIG. 6). The Mark Detection System (MDS) has an alignment autofocus function that adjusts the focal position of the optical system.

[0051] Between the barrel portion (41) and the support plate (44), a head mounting member (51) in the shape of a roughly isosceles triangle is disposed as shown in FIG. 1. An opening is formed in the head mounting member (51) that penetrates in the direction of the Y-axis of FIG. 1, and the barrel portion (41) is mounted (fixed) to the support plate (44) by means of a mounting member (not shown) inserted into the opening. Also, the back surface of the head mounting member (51) is fixed to the support plate (44). In this way, the barrel portion (41) (mark detection system (MDS)), the head mounting member (51), and the support plate (44) are integrated with the unit body (42) by means of a pair of support arms (45a, 45b).

[0052] Inside the unit body (42), the aforementioned signal processing device (49) is arranged to process the imaging signal output as a detection signal from the mark detection system (MDS), calculate position information of the target mark relative to the detection center, and output it to the control device (60). The unit body (42) is supported at three points from below by interposing a plurality, for example, three vibration damping devices (48), on a gate-shaped support frame (46) that is installed on the base frame (16) when viewed from the -Y side. Each vibration isolation device (48) is an active vibration isolation system (so-called AVIS (Active Vibration Isolation System)) and is equipped with an accelerometer, a displacement sensor (e.g., a capacitive sensor, etc.), an actuator (e.g., a voice coil motor, etc.), and a mechanical damper such as an air damper or a hydraulic damper, and the vibration isolation device (48) can dampen relatively high frequency vibrations by the mechanical damper and also dampen (control vibration) by the actuator. Accordingly, each vibration isolation device (48) can avoid the transmission of relatively high frequency vibrations between the support frame (46) and the unit body (42).

[0053] In addition, the mark detection system (MDS) is not limited to an FIA system, and instead of an FIA system, a diffraction light interference type alignment detection system may be used, for example, to irradiate a target mark with coherent detection light and detect two diffraction lights (for example, diffraction lights of the same order or diffraction lights diffracted in the same direction) generated from the target mark by interfering them and outputting a detection signal. Alternatively, a diffraction light interference type alignment system may be used together with an FIA system to detect two target marks simultaneously. In addition, as the mark detection system (MDS), a beam scan type alignment system may be used to scan the target mark with a measurement light in a predetermined direction while the slider (10) is moving in a predetermined direction. In addition, in this embodiment, the mark detection system (MDS) is configured to have an alignment autofocus function, but instead of this, or in addition to this, the measurement unit (40) may be equipped with a focus position detection system, for example, a multi-point focus position detection system of the light incident type having the same configuration as disclosed in U.S. Patent No. 5,448,332, etc.

[0054] As shown in FIG. 2(B) and FIG. 3, the first position measuring system (30) has a head portion (32) fixed to the platen (12) and disposed within a concave portion formed on the upper surface of the platen (12). The upper surface of the head portion (32) faces the lower surface of the slider (10) (the surface formed by the grating (RG1)). A predetermined clearance (gap), for example, a clearance of several mm, is formed between the upper surface of the head portion (32) and the lower surface of the slider (10).

[0055] As shown in FIG. 6, the first position measurement system (30) is equipped with an encoder system (33) and a laser interferometer system (35). The encoder system (33) can obtain position information of the slider (10) by irradiating a plurality of beams from the head part (32) onto the measurement part (forming surface of the grating (RG1)) on the lower surface of the slider (10) and receiving a plurality of return beams (e.g., a plurality of diffracted beams from the grating (RG1)) from the measurement part on the lower surface of the slider (10). The encoder system (33) includes an X linear encoder (33x) for measuring the position of the slider (10) in the X-axis direction and a pair of Y linear encoders (33ya, 33yb) for measuring 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 the encoder head (hereinafter appropriately abbreviated as head) disclosed, for example, in U.S. Patent No. 7,238,931 and U.S. Patent Application Publication No. 2007 / 288,121, etc. is used. In addition, the head includes a light source and a light receiving system (including a light detector) and an optical system, but in the present embodiment, at least the optical system among these may be disposed inside the casing of the head part (32) facing the grating (RG1), and at least one of the light source and the light receiving system may be disposed outside the casing of the head part (32).

[0056] In FIG. 4(A), a head portion (32) is shown in a perspective view, and in FIG. 4(B), a top surface of the head portion (32) is shown in a plan view 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 in the Y-axis direction with one pair of Y heads (37ya, 37yb) (see FIG. 4(B)). That is, the aforementioned X linear encoder (33x) is configured by an X head (37x) that measures the X-axis position of the slider (10) using the X diffraction grating of the grating (RG1), and a pair of Y linear encoders (33ya, 33yb) are configured by a pair of Y heads (37ya, 37yb) that measure the Y-axis position of the slider (10) using the Y diffraction grating of the grating (RG1).

[0057] As shown in FIGS. 4(A) and FIGS. 4(B), the X head (37x) irradiates measurement beams (LBx1, LBx2) (shown as solid lines in FIG. 4(A)) to the same irradiation point on the grating (RG1) from two points (see white circles in FIG. 4(B)) that are equidistant from the line (CL) parallel to the Y-axis passing through the center of the head part (32) and from the line (LX) parallel to the X-axis passing through the center of the head part (32). The irradiation point of the measurement beams (LBx1, LBx2), that is, the detection point of the X head (37x) (see symbol (DP) in FIG. 4(B)), is positioned in the X-axis direction and Y-axis direction at the detection center of the mark detection system (MDS).

[0058] Here, the measurement beams (LBx1, LBx2) are polarized separated by a polarizing beam splitter from a light source, and when the measurement beams (LBx1, LBx2) are irradiated onto the grating (RG1), the X-order diffracted beams (first diffracted beams) of a predetermined order, for example, the first diffracted beam (first diffracted beam), which are diffracted by the X-order diffracted grating of these measurement beams (LBx1, LBx2), are each folded back and bent at a reflecting mirror through a lens (not shown) and a quarter-wave plate, and by passing through the quarter-wave plate twice, the polarization direction is rotated by 90 degrees, and then pass through the original optical path and are incident again on the polarizing beam splitter, and after being combined coaxially, the interference light between the first diffracted beams of the measurement beams (LBx1, LBx2) is received by a photodetector (not shown), thereby measuring the X-axis position of the slider (10).

[0059] As shown in FIG. 4(B), each of the pair of Y heads (37ya, 37yb) is positioned on the +X side and -X side of the straight line (CL). As shown in FIG. 4(A) and FIG. 4(B), the Y head (37ya) irradiates measurement beams (LBya1, LBya2), indicated by dashed lines in FIG. 4(A), to a common irradiation point on the grating (RG1) from two points (see white circles in FIG. 4(B)) that are equidistant from the straight line (LX) on the straight line (LYa). The irradiation point of the measurement beams (LBya1, LBya2), i.e., the detection point of the Y head (37ya), is indicated by the symbol (DPya) in FIG. 4(B).

[0060] The Y head (37yb) irradiates the measurement beams (LByb1, LByb2) from two points (see white circles in FIG. 4(B)) symmetric to the injection points of the measurement beams (LBya1, LBya2) of the Y head (37ya) with respect to the straight line (CL) onto a common irradiation point (DPyb) on the grating (RG1). As shown in FIG. 4(B), the detection points (DPya, DPyb) of each Y head (37ya, 37yb) are positioned on a straight line (LX) parallel to the X-axis.

[0061] Measurement beams (LBya1, LBya2) are also the same beams that have been polarized by a polarizing beam splitter, and the interference light between the first-order diffraction beams (second-order diffraction beams) of a predetermined order by the Y-diffraction grating of these measurement beams (LBya1, LBya2) is photoelectrically detected by a photodetector not shown in the same manner as described above, thereby measuring the position of the slider (10) in the Y-axis direction. For measurement beams (LByb1, LByb2) as well, the interference light between the first-order diffraction beams (second-order diffraction beams) is photoelectrically detected by a photodetector not shown in the same manner as the measurement beams (LBya1, LBya2), thereby measuring the position of the slider (10) in the Y-axis direction.

[0062] Here, the control device (60) determines the position of the slider (10) in the Y-axis direction based on the average of the measurement values ​​of two Y heads (37ya, 37yb). Accordingly, in this embodiment, the position of the slider (10) in the Y-axis direction is measured using the midpoint (DP) of the detection points (DPya, DPyb) as the actual measurement point. The midpoint (DP) coincides with the irradiation point on the grating (RG1) of the measurement beams (LBx1, LBx2).

[0063] That is, in this embodiment, regarding the measurement of position information in the X-axis and Y-axis directions of the slider (10), there is a common detection point, and the actuators of the three vibration damping devices (14) are always controlled in real time by the control device (60) based on the relative position information of the mark detection system (MDS) (measurement unit (40)) and the platen (12) measured by the second position measurement system (50), so that the position of the detection point in the XY plane coincides with the detection center of the mark detection system (MDS). Accordingly, in this embodiment, the control device (60) can always measure the position information in the XY plane of the slider (10) directly below the detection center of the mark detection system (MDS) (on the back side of the slider (10)) by using the encoder system (33) when measuring the alignment mark on the wafer (W) placed on the slider (10). Also, the control device (60) measures the amount of rotation in the θz direction of the slider (10) based on the difference in the measured values ​​of a pair of Y heads (37ya, 37yb).

[0064] A laser interferometer (35) can obtain position information of the slider (10) by irradiating a measurement beam onto the lower surface of the slider (10) (the surface on which the grating (RG1) is formed) and receiving the return beam (e.g., reflected light from the surface on which the grating (RG1) is formed). As shown in FIG. 4(A), the laser interferometer system (35) irradiates four measurement beams (LBz1, LBz2, LBz3, LBz4) onto the lower surface of the slider (10) (the surface on which the grating (RG1) is formed). The laser interferometer system (35) is equipped with laser interferometers (35a to 35d) (see FIG. 6) that irradiate each of these four measurement beams (LBz1, LBz2, LBz3, LBz4). In this embodiment, four Z heads are configured by laser interferometers (35a to 35d).

[0065] In the laser interferometer system (35), as shown in FIG. 4(A) and FIG. 4(B), four measurement beams (LBz1, LBz2, LBz3, LBz4) are emitted parallel to the Z-axis from four points corresponding to each vertex of a square having two sides parallel to the X-axis and two sides parallel to the Y-axis, centered on the detection point (DP). In this case, the emission points (irradiation points) of the measurement beams (LBz1, LBz4) are equidistant from the straight line (LX) on the straight line (LYa), and the emission points (irradiation points) of the remaining measurement beams (LBz2, LBz3) are equidistant from the straight line (LX) on the straight line (LYb). In this embodiment, the surface on which the grating (RG1) is formed also serves as the reflection surface for each measurement beam from the laser interferometer system (35). The control device (60) measures information regarding the position of the slider (10) in the Z-axis direction and the amount of rotation in the θx and θy directions using a laser interferometer system (35). Additionally, as is evident from the description above, the slider (10) is not actively driven by the aforementioned drive system (20) with respect to the Z-axis, θx and θy directions, but is supported by floating on the platen (12) by four air bearings (18) placed at the four corners of the bottom surface, so in reality, the position of the slider (10) changes with respect to the Z-axis, θx and θy directions on the platen (12). That is, the slider (10) is actually movable with respect to the platen (12) with respect to the Z-axis, θx and θy directions. In particular, the displacement of the slider (10) in each direction of θx and θy causes a measurement error (Abbe error) of the encoder system (33). Taking this into consideration, the position information of the slider (10) in each direction of the Z-axis, θx, and θy is measured by the first position measurement system (30) (laser interferometer system (35)).

[0066] Additionally, for measuring information on the position of the slider (10) in the Z-axis direction and the amount of rotation in the θx and θy directions, it is sufficient to be able to incident a beam on three different points on the surface where the grating (RG1) is formed, so three Z heads, for example, laser interferometers, are required. Additionally, a protective glass may be formed on the lower surface of the slider (10) to protect the grating (RG1), and a wavelength selection filter may be formed on the surface of the protective glass to transmit each measurement beam from the encoder system (33) and to block the transmission of each measurement beam from the laser interferometer system (35).

[0067] As can be seen from the above description, the control device (60) can measure the position of the slider (10) in six degrees of freedom directions 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), the optical path length of the measurement beam in the air is extremely short and also almost identical, so the effect of air vibration can be almost ignored. Therefore, the position information of the slider (10) within the XY plane (including the θz direction) can be measured with high precision by the encoder system (33). Additionally, the detection points on the actual grating (RG1) in the X-axis direction and Y-axis direction by the encoder system (33), and the detection points on the lower surface of the slider (10) in the Z-axis direction by the laser interferometer system (35) each coincide with the detection center of the mark detection system (MDS) in the XY plane, so the occurrence of so-called Abbe error caused by the misalignment between the detection points and the detection center of the mark detection system (MDS) in the XY plane is suppressed to the extent that it can be substantially ignored. Accordingly, the control device (60) can measure the positions of the slider (10) in the X-axis direction, Y-axis direction, and Z-axis direction with high precision without Abbe error caused by the misalignment between the detection points and the detection center of the mark detection system (MDS) in the XY plane by using the first position measurement system (30).

[0068] However, regarding the Z-axis direction parallel to the optical axis (AX1) of the mark detection system (MDS), the position information within the XY plane of the slider (10) is not measured by the encoder system (33) at the position on the surface of the wafer (W), that is, the Z position of the arrangement plane of the grating (RG1) and the surface of the wafer (W) do not coincide. 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 measurement value of each encoder of the encoder system (33), as a result, a positioning error (a type of Abbe error) occurs due to the inclination of the grating (RG1) with respect to the XY plane, which is caused by the difference (ΔZ) in the Z position between the placement plane of the grating (RG1) and the surface of the wafer (W) (i.e., the misalignment 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)). However, this positioning error (position control error) can be obtained by a simple calculation using the difference (ΔZ), pitching amount (θx), and rolling amount (θy), and by using this as an offset and correcting the measured value of the encoder system (33) (each encoder) by the amount of the offset, the slider (10) is positioned based on the corrected position information, thereby avoiding the influence of the above-mentioned type of Abbe error. Alternatively, instead of correcting the measured value of the encoder system (33) (each encoder), one or more pieces of information for moving the slider, such as the target position to which the slider (10) is to be positioned, may be corrected based on the above-mentioned offset.

[0069] Additionally, if the grating (RG1) (i.e., the slider (10)) is inclined with respect to the XY plane, the head portion (32) may be moved so as not to cause a positioning error resulting from the inclination. That is, if the grating (RG1) (i.e., the slider (10)) is measured to be inclined with respect to the XY plane by the first position measuring system (30) (e.g., the interferometer system (35)), the platen (12) holding the head portion (32) may be moved based on the position information obtained using the first position measuring system (30). The platen (12) may be moved using the vibration damping device (14) as described above.

[0070] In addition, if 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.

[0071] As shown in FIG. 1, FIG. 2(A) and FIG. 2(B), the second position measurement system (50) has a pair of head portions (52A, 52B) formed on the lower surface of one end and the other end in the longitudinal direction of the head mounting member (51) described above, and scale members (54A, 54B) positioned opposite to the head portions (52A, 52B). The upper surface of the scale members (54A, 54B) is at the same height as the surface of the wafer (W) held in the wafer holder (WH). On the upper surface of each scale member (54A, 54B), a reflective two-dimensional grating (RG2a, RG2b) is formed. The two-dimensional gratings (hereinafter abbreviated as gratings) (RG2a, RG2b) both include a reflective diffraction grating (X diffraction grating) with the X-axis direction as the periodic direction and a reflective diffraction grating (Y diffraction grating) with 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.

[0072] The scale members (54A, 54B) are made of a material with a low thermal expansion coefficient, for example, the aforementioned zero expansion material, and are fixed on the platen (12) with a support member (56) interposed therebetween, as shown in FIG. 2(A) and FIG. 2(B). In this embodiment, the dimensions of the scale members (54A, 54B) and the support member (56) are determined such that the grating (RG2a, RG2b) and the head part (52A, 52B) face each other with a gap of about a few millimeters.

[0073] As shown in FIG. 5, one head part (52A) fixed to the lower surface of the +X side end of the head mounting 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, which are housed inside the same casing. The XZ head (58X1) (more precisely, the point of irradiation on the grating (RG2a) of the measurement beam emitted by the XZ head (58X1)) and the YZ head (58Y1) (more precisely, the point of irradiation 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.

[0074] The other head unit (52B) is arranged symmetrically with respect to the head unit (52A) with respect to a straight line parallel to the Y-axis (hereinafter referred to as the reference axis) (LV) passing through the optical axis (AX1) of the mark detection system (MDS), but is configured identically to the head unit (52A). That is, the head unit (52B) has an XZ head (58X2) and a YZ head (58Y2) arranged symmetrically with respect to the reference axis (LV) with respect to the XZ head (58X1) and YZ head (58Y1), and the irradiation points of the measurement beams irradiated onto the grating (RG2b) from each of the XZ head (58X2) and YZ head (58Y2) are set on a straight line parallel to the same Y-axis. Here, the reference axis (LV) coincides with the aforementioned straight line (CL).

[0075] For 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 may be used.

[0076] The head portions (52A, 52B) each use scale members (54A, 54B) to form an XZ linear encoder that measures the X-axis position (X position) and Z-axis position (Z position) of the grating (RG2a, RG2b), and a YZ linear encoder that measures the Y-axis position (Y position) and Z position. Here, the grating (RG2a, RG2b) is formed on the upper surface of the scale members (54A, 54B) fixed by interposing a support member (56) on the surface plate (12), and the head portions (52A, 52B) are formed on a head mounting member (51) that is integral with the mark detection system (MDS). As a result, the head unit (52A, 52B) measures the position of the platen (12) relative to the mark detection system (MDS) (the positional relationship between the mark detection system (MDS) and the platen (12)). Hereinafter, for convenience, the XZ linear encoder and the YZ linear encoder are referred to as the XZ linear encoder (58X1, 58X2) and the YZ linear encoder (58Y1, 58Y2), respectively, using the same symbols as the XZ head (58X1, 58X2) and the YZ head (58Y1, 58Y2) (see FIG. 6).

[0077] In this embodiment, a 4-axis encoder (581) is configured by an XZ linear encoder (58X1) and a YZ linear encoder (58Y1) to measure position information regarding each direction of the X-axis, Y-axis, Z-axis, and θx for the mark detection system (MDS) of the platen (12) (see FIG. 6). Likewise, a 4-axis encoder (582) is configured by an XZ linear encoder (58X2) and a YZ linear encoder (58Y2) to measure position information regarding each direction of the X-axis, Y-axis, Z-axis, and θx for the mark detection system (MDS) of the platen (12) (see FIG. 6). In this case, based on position information regarding the Z-axis direction of the mark detection system (MDS) of the platen (12) measured by each of the 4-axis encoders (581, 582), position information regarding the θy direction of the mark detection system (MDS) of the platen (12) is obtained (measured), and based on position information regarding the Y-axis direction of the mark detection system (MDS) of the platen (12) measured by each of the 4-axis encoders (581, 582), position information regarding the θz direction of the mark detection system (MDS) of the platen (12) is obtained (measured).

[0078] Accordingly, a second position measurement system (50) is configured to measure position information in the 6 degrees of freedom direction for the mark detection system (MDS) of the platen (12), that is, information on the relative position of the mark detection system (MDS) and the platen (12) in the 6 degrees of freedom direction by means of a 4-axis encoder (581) and a 4-axis encoder (582). Information regarding the relative position of the mark detection system (MDS) and the platen (12) in the 6 degrees of freedom direction, measured by the second position measurement system (50), is always supplied to the control device (60), and the control device (60), based on this relative position information, controls the actuators of the three vibration damping devices (14) in real time so that the detection point of the first position measurement system (30) becomes in a desired positional relationship with respect to the detection center of the mark detection system (MDS), specifically, so that the position of the detection point of the first position measurement system (30) in the XY plane with respect to the detection center of the mark detection system (MDS) coincides, for example, at the nm level, and also so that the surface of the wafer (W) on the slider (10) coincides with the detection position of the mark detection system (MDS). At this time, for example, the aforementioned straight line (CL) coincides with the reference axis (LV). Additionally, 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 need to be able to measure relative position information in all directions of the 6 degrees of freedom.

[0079] FIG. 6 shows a block diagram illustrating the input-output relationship of a control device (60) that primarily constitutes the control system of a measuring device (100) related to the present embodiment. The control device (60) includes a workstation (or microcomputer), etc., and comprehensively controls each component of the measuring device (100). As shown in FIG. 6, the measuring device (100) is equipped with a wafer transport system (70) disposed within a chamber together with the component shown in FIG. 1. The wafer transport system (70) is, for example, composed of a horizontal multi-joint robot.

[0080] Next, regarding the measurement device (100) related to the present embodiment configured as described above, a series of operations when processing one lot of wafers will be explained based on the flowchart of FIG. 7 corresponding to the processing algorithm of the control device (60).

[0081] As a premise, the wafer (W) to be measured by the measuring device (100) is a 300 milli wafer, and on the wafer (W), by exposure prior to the entire layer, a plurality of partitioned regions called shot regions (hereinafter also referred to as shots) are formed in a matrix arrangement, for example, I (for example, I = 98), and on the street line surrounding each shot or the street line inside each shot (in the case of acquiring multiple chips in one shot), a plurality of types of marks, for example, a search alignment mark for search alignment (search mark), a wafer alignment mark for fine alignment (wafer mark), etc. are formed. These plurality of types of marks are formed together with the partitioned regions. In this embodiment, two-dimensional marks are used as search marks and wafer marks.

[0082] Additionally, the measuring device (100) is capable of setting multiple measuring modes in which the mark detection conditions by the mark detection system (MDS) are different from each other. As for the multiple measuring modes, as an example, mode A is capable of detecting one wafer mark for each shot for all wafers, and mode B is capable of detecting multiple wafer marks for all shots for the first predetermined number of wafers in the lot, and determining the wafer mark to be detected for each shot for the remaining wafers in the lot according to the detection result of the wafer marks, and detecting the determined wafer marks.

[0083] Additionally, information required for alignment measurement of a wafer (W) is input in advance by an operator of the measuring device (100) through an input device not shown and stored in the memory of the control device (60). Here, the information required for alignment measurement includes various information such as thickness information of the wafer (W), flatness information of the wafer holder (WH), and design information of the arrangement of the short area and alignment mark on the wafer (W). In addition, setting information for the measurement mode is input in advance, for example, by an operator through an input device not shown.

[0084] The processing algorithm corresponding to the flowchart of FIG. 7 starts when, for example, the start of measurement is instructed by an operator. At this time, the wafer of lot 1 is contained within a wafer carrier at a predetermined location. It is not limited thereto, for example, when the measurement device (100) is connected inline to a substrate processing device (e.g., a coater / developer, etc.), the algorithm may start when there is a request for permission to start transporting the wafer of lot 1 from the control system of the substrate processing device, and in response to that request, the first wafer is brought into a predetermined receiving location. Furthermore, being connected inline means that different devices are connected while the transport path of the wafer (substrate) is connected, and in this specification, the terms "inline connection" or "inline connection" are used in this sense.

[0085] First, in step S102, the counter value i representing the wafer number in the lot is initialized to 1 (i ← 1).

[0086] In the next step S104, a wafer (W) is loaded onto a slider (10). The loading of the wafer (W) is carried out by a wafer transport system (70) and an up-and-down moving member on the slider (10) under the management of a control device (60). Specifically, the wafer (W) is transported by the wafer transport system (70) from a wafer carrier (or receiving position) to the upper side of the slider (10) in the loading position, and the wafer (W) is transferred to the up-and-down moving member by driving the up-and-down moving member by a predetermined amount by a driving device (13). Then, after the wafer transport system (70) is withdrawn from the upper side of the slider (10), the wafer (W) is placed on a wafer holder (WH) on the slider (10) by driving the up-and-down moving member downward by the driving device (13). Then, the vacuum pump (11) is turned on, and the wafer (W) loaded on the slider (10) is vacuum-adsorbed to the wafer holder (WH). Also, if the measuring device (100) is connected in-line to the substrate processing device, sequential wafers are brought in from the wafer transport system on the substrate processing device side and placed at the receiving position.

[0087] In the next step S106, the position (Z position) of the wafer (W) in the Z-axis direction is adjusted. Prior to this adjustment of the Z position, the internal pressure of the air mounts of the three vibration damping devices (14) (the driving force in the Z-axis direction generated by the vibration damping devices (14)) is controlled by the control device (60) based on relative position information regarding the Z-axis direction, θy direction, and θx direction of the mark detection system (MDS) measured by the second position measurement system (50), and the upper surface of the platen (12) is set so that the Z position becomes a predetermined reference position. The wafer (W) is thought to have a uniform thickness. Accordingly, in step S106, the control device (60) adjusts the Z-axis driving force generated by three vibration damping devices (14), for example, the internal pressure (amount of compressed air) of the air mount, by driving the surface plate (12) in the Z-axis direction so that the surface of the wafer (W) is set to an adjustable range for the focal position of the optical system by the autofocus function of the mark detection system (MDS) based on the thickness information of the wafer (W) in the memory, thereby adjusting the Z-axis position of the wafer (W) surface. Additionally, if the measurement unit (40) is equipped with a focal position detection system, the control device (60) may perform Z-axis position adjustment of the wafer surface based on the detection result (output) of the focal position detection system. For example, the mark detection system (MDS) may be equipped with a focal position detection system that detects the position in the Z-axis direction of the wafer (W) surface by interposing an optical element (objective optical element) at the leading edge. Additionally, the adjustment of the Z position of the wafer (W) surface based on the detection result of the focus position detection system can be performed by moving the platen (12) using the vibration damping device (14) and moving the slider (10) together with the platen (12).Additionally, a driving system (20) configured 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 driving system (20). Additionally, the Z-position adjustment of the wafer surface may include the tilt adjustment of the wafer surface. If there is a possibility that an error (a type of Abbe error) may occur due to the difference (ΔZ) between the Z-position of the arrangement surface of the grating (RG1) and the wafer (W) surface when using the driving system (20) to adjust the tilt of the wafer surface, at least one of the countermeasures described above may be implemented.

[0088] In the following step S108, search alignment of the wafer (W) is performed. Specifically, for example, at least two search marks located in the periphery, which are nearly symmetric with respect to the center of the wafer (W), are detected using a mark detection system (MDS). The control device (60) controls the driving of the slider (10) by the driving system (20) to position each search mark within the detection area (detection field of view) of the mark detection system (MDS), acquires measurement information from the first position measurement system (30) and measurement information from the second position measurement system (50), and obtains position information of each search mark 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 from the first position measurement system (30) (and measurement information from the second position measurement system (50)).

[0089] More specifically, the control device (60) obtains the position coordinates of two search marks on a reference coordinate system based on the detection result of the mark detection system (MDS) output from the signal processing device (49) (the detection center (index center) of the mark detection system (MDS) obtained from the detection signal and the relative position relationship of each search mark), the measurement value of the first position measurement system (30) and the measurement value of the second position measurement system (50) at the time of each search mark detection. Here, the reference coordinate system is an orthogonal coordinate system defined by the measurement axis of the first position measurement system (30).

[0090] Then, the residual rotation error of the wafer (W) is calculated from the position coordinates of the two search marks, and the slider (10) is rotated slightly so that this rotation error becomes nearly zero. With this, the search alignment of the wafer (W) is completed. In addition, since the wafer (W) is actually loaded onto the slider (10) in a state where pre-alignment has been performed, the center position misalignment of the wafer (W) is small enough to be negligible, and the residual rotation error is very small.

[0091] In the next step S110, it is determined whether the set measurement mode is mode A. Then, if the determination in step S110 is positive, that is, if mode A is set, the process proceeds to step S112.

[0092] In step S112, alignment measurement for the entire wafer (one-point measurement of the entire short, in other words, one-point measurement of the entire short EGA), that is, one wafer mark is measured for each of the 98 shorts. Specifically, the control device (60) obtains the position coordinates of the wafer marks on the wafer (W) in the reference coordinate system, i.e., the position coordinates of the short, in the same way as the measurement of the position coordinates of each search mark during the search alignment described above. However, in this case, unlike during the search alignment, the measurement information of the second position measurement system (50) must be used when calculating the position coordinates of the short. The reason is that, as described above, the actuators of three vibration damping devices (14) are controlled in real time by the control device (60) based on the measurement information of the second position measurement system (50) so that the detection point of the first position measurement system (30) matches the position in the XY plane with the detection center of the mark detection system (MDS) at, for example, at the nm level, and also so that the surface of the wafer (W) on the slider (10) matches the detection position of the mark detection system (MDS). However, when detecting a wafer mark, there is no guarantee that the detection point of the first position measurement system (30) matches the position in the XY plane with the detection center of the mark detection system (MDS) at, for example, at the nm level, so it is necessary to calculate the position coordinates of the shot by taking into account the amount of positional misalignment 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 measurement value of the first position measurement system (30), the position coordinates of the wafer mark on the wafer (W) in the reference coordinate system can be corrected.

[0093] Here, when measuring one point of the entire shot, 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 driving system (20) to position the wafer mark within the detection area 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 one point of the entire shot is measured.

[0094] In addition, if the measurement unit (40) is equipped with a focus position detection system, 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, just as described in step S106.

[0095] When the slider (10) moves within the XY plane during the alignment measurement (one-point measurement of the entire wafer) of step S112, an uneven load is applied to the platen (12) in conjunction with the movement. However, in this embodiment, the control device (60) individually feed-forward controls three vibration damping devices (14) according to the X and Y coordinate positions of the slider included in the measurement information of the first position measurement system (30) so that the effect of the uneven load is offset, and individually controls the driving force in the Z-axis direction generated by each vibration damping device (14). Additionally, the control device (60) may predict the uneven load acting on the platen (12) based on information of the already known movement path of the slider (10) without using the measurement information of the first position measurement system (30), and individually feed-forward controls the three vibration damping devices (14) so ​​that the effect of the uneven load is offset. In addition, in this embodiment, since the information on the irregularities of the wafer holding surface of the wafer holder (WH) (a surface defined from the upper surface of a plurality of pins of the pin chuck) (hereinafter referred to as holder flatness information) is obtained in advance through experiments, when moving the slider (10) during alignment measurement (e.g., total shot 1-point measurement), the control device (60) finely adjusts the Z position of the platen (12) by feed-forward controlling three vibration damping devices (14) based on the holder flatness information so that the area containing the wafer mark to be measured on the surface of the wafer (W) is quickly positioned within the range of the depth of focus of the optical system of the mark detection system (MDS). Furthermore, either or both of the feed-forward control to offset the effect of the uneven load acting on the platen (12) described above and the feed-forward control based on the holder flatness information do not need to be performed.

[0096] In addition, if the magnification of the mark detection system (MDS) can be adjusted, it may be set to a low magnification during search alignment and to a high magnification during alignment measurement. Also, if the center position misalignment and residual rotation error of the wafer (W) loaded on the slider (10) are small enough to be ignored, step S108 may be omitted.

[0097] In the total shot one-point measurement in step S112, the actual value of the position coordinates of the sample shot area (sample shot) in the reference coordinate system used in the EGA calculation described later is detected. A sample shot refers to a predetermined specific plurality (at least 3) of shots among all shots on the wafer (W) that are used in the EGA calculation described later. In addition, in the total shot one-point measurement, all shots on the wafer (W) become sample shots. After step S112, proceed to step S124.

[0098] Meanwhile, if the judgment in step S110 is denied, that is, if mode B is set, proceed to step S114 and determine whether the count value i is smaller than a predetermined number K (where K is a natural number satisfying 1 < K < I and is a predetermined number, for example, 4). Additionally, the count value i is increased in step S128, which is described later. Then, if the judgment in step S114 is affirmed, proceed to step S120 and perform total shot multi-point measurement. Here, total shot multi-point measurement means measuring multiple wafer marks for each of all shots on the wafer (W). The multiple wafer marks to be measured are predetermined. For example, multiple wafer marks of a batch for which the shape of the shot (shape error from the ideal grid) can be obtained by statistical calculation may be the measurement targets. The measurement sequence is the same as the one-point measurement of the entire shot in step S112, except that the number of marks of the measurement target is different, so a detailed description is omitted. After step S120, proceed to step S124.

[0099] Meanwhile, if the judgment in step S114 is denied, proceed to step S116 and determine whether the count value i is less than K + 1. Here, the judgment in step S116 is affirmed because the count value i is i ≥ K and i < k + 1, so it becomes the case where i = K.

[0100] If the judgment of step S116 is affirmed, proceed to step S118, and based on the detection results of wafer marks for K - 1 wafers (e.g., 3 wafers in the case of K = 4) that have been measured up to that point, determine the wafer marks to be measured for each shot. Specifically, determine whether it is sufficient to detect one wafer mark for each shot or to detect multiple wafer marks. In the latter case, determine which wafer marks to be detected. For example, for each shot, calculate the difference (absolute value) between the actual position and the design position of each of the multiple wafer marks, and determine whether it is sufficient to detect multiple wafer marks or one wafer mark for each shot based on whether the difference between the maximum and minimum values ​​of that difference exceeds a certain threshold value. In the former case, for example, the wafer marks to be detected are determined such that the wafer mark where the difference (absolute value) between the actual position and the design position is maximum and the wafer mark where it is minimum are included. After Step S118, proceed to Step S122.

[0101] Meanwhile, if the judgment in step S116 is denied, proceed to step S122. Here, the judgment in step S116 is denied when the count value i satisfies K + 1 ≤ i, and before that, the count value i = K and the wafer mark to be measured for each shot is determined in step S118.

[0102] In step S122, the wafer marks to be measured, determined for each shot in step S118, are measured. The measurement sequence is the same as the one-point measurement of the entire shot in step S112, except that the number of marks to be measured is different, so a detailed description is omitted. After step S122, proceed to step S124.

[0103] As can be seen from the explanation so far, in the case of B mode, for the wafers from the 1st to the K-1st (e.g., the 3rd) in the lot, total shot multi-point measurement is performed, and for the wafers from the Kth (e.g., the 4th) to the 1st (e.g., the 25th), measurement of wafer marks determined for each shot is performed based on the result of total shot multi-point measurement of the first K-1st (e.g., the 3rd) wafer.

[0104] In step S124, an EGA operation is performed using the wafer mark position information measured in any of steps S112, S120, and S122. An EGA operation refers to a statistical operation that, after the measurement of the wafer mark described above (EGA measurement), uses statistical operations such as the least squares method based on the data of the difference between the design value and the actual value of the sample shot position coordinates to obtain the coefficients of a model equation that express the relationship between the shot position coordinates and the correction amount of the shot position coordinates.

[0105] In this embodiment, as an example, the following model formula is used to calculate the correction amount from the design value of the shot position coordinates.

[0106]

[0107] Here, dx and dy are correction amounts in the X-axis and Y-axis directions from the design values ​​of the position coordinates of the shot, and X and Y are the design position coordinates of the shot in the wafer coordinate system with the center of the wafer (W) as the origin. That is, the above equation (1) is a polynomial relating to the design position coordinates (X, Y) of each shot in the wafer coordinate system with the center of the wafer as the origin, and is a model equation expressing the relationship between the position coordinates (X, Y) and the correction amount (alignment correction component) (dx, dy) of the position coordinates of the shot. Furthermore, in this embodiment, since the rotation of the reference coordinate system and the wafer coordinate system is canceled by the aforementioned search alignment, the reference coordinate system and the wafer coordinate system will not be specifically distinguished below, and both will be described as the reference coordinate system.

[0108] Using model equation (1), the correction amount of the position coordinates of the short on the wafer (W) can be obtained from the position coordinates (X, Y) of the short. However, to calculate this correction amount, it is necessary to obtain coefficients (a0, a1, …, b0, b1, …). After EGA measurement, based on the data of the difference between the design value and the actual value of the sample short's position coordinates, statistical operations such as the least squares method are used to obtain the coefficients (a0, a1, …, b0, b1, …) of equation (1).

[0109] After determining the coefficients (a0, a1, …, b0, b1, …) of model equation (1), the design position coordinates (X, Y) of each shot (partition area) in the wafer coordinate system are substituted into model equation (1) after determining the coefficients, and by calculating the correction amount (dx, dy) of the position coordinates of each shot, the true arrangement of multiple shots (partition areas) on the wafer (W) (including not only linear components but also non-linear components as deformation components) can be obtained.

[0110] However, in the case of a wafer (W) that has already been exposed, the waveform of the detection signal obtained as a measurement result cannot be said to be good for all wafer marks due to the influence of the process so far. If the location of the wafer mark with a defective measurement result (waveform of the detection signal) is included in the above EGA calculation, the position error of the wafer mark with a defective measurement result (waveform of the detection signal) has an adverse effect on the calculation result of the coefficients (a0, a1, …, b0, b1, …).

[0111] Therefore, in this embodiment, the signal processing device (49) sends only the measurement results of wafer marks with good measurement results to the control device (60), and the control device (60) executes the EGA calculation described above using the locations of all wafer marks that received the measurement results. In addition, there is no particular limit on the degree of the polynomial of the above equation (1). The control device (60) creates an alignment history data file by matching the result of the EGA calculation with wafer identification information (e.g., wafer number, lot number) along with information regarding the mark used in the calculation, and stores it in an internal or external memory device.

[0112] When the EGA operation of step S124 is completed, the process proceeds to step S126, and the wafer (W) is unloaded from the slider (10). This unloading is carried out by the wafer transport system (70) and the up-and-down moving member on the slider (10) in the reverse order of the loading in step S104, under the management of the control device (60).

[0113] In the following step S128, the counter value i is increased by 1 (i ← i + 1), and then the process proceeds to step S130, where it is determined whether the counter value i is greater than the total number of wafers I in the lot. Then, if the determination in step S130 is denied, it is determined that the processing for all 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 affirmed.

[0114] And, if the judgment in step S130 is affirmed, it is determined that processing is completed for all wafers in the lot, and the series of processing of this routine is terminated.

[0115] As described in detail above, according to the measuring device (100) related to the present embodiment, the first position measuring system (30) for measuring position information in the 6 degrees of freedom direction of the slider (10) on which the wafer (W) is placed and maintained detects at least the wafer mark on the wafer (W) using a mark detection system (MDS), so that the measuring beam from the head part (32) can be continuously irradiated onto the grating (RG1) within the range in which the slider (10) moves. Therefore, the first position measuring system (30) can continuously measure the position information within the entire range within the XY plane in which the slider (10) moves for mark detection. Accordingly, for example, in the manufacturing stage of the measuring device (100) (including the starting stage of the device within the semiconductor manufacturing plant), by forming the origin of an orthogonal coordinate system (reference coordinate system) defined by the measurement axis of the first position measuring system (30), that is, by the grid of the grating (RG1), it becomes possible to obtain the absolute coordinate position of the slider (10) within the XY plane, and furthermore, it becomes possible to obtain the absolute position within the XY plane of a mark on the wafer (W) maintained on the slider (10) (not limited to search marks and wafer marks, but also includes other marks, such as overlapping measurement marks (registration marks), etc.) obtained from the position information of the slider (10) measured by the first position measuring system (30) and the detection result of the mark detection system (MDS). In addition, in this specification, "absolute position coordinate" means the position coordinate on the above reference coordinate system.

[0116] In addition, according to the measuring device (100) related to the present embodiment, since the position coordinates of a mark on a wafer within the XY plane can be measured, exposure is performed on a bare wafer in a step-and-scan or step-and-repeat manner using a product reticle formed with an alignment mark that has a known positional relationship with the pattern area along with a rectangular pattern area, for example, by an exposure device such as a scanner or a stepper, and the absolute coordinates of the alignment mark image on the wafer after exposure are measured by the measuring device (100), thereby making it possible to manage wafer grid variation (for example, variation from the design wafer grid) without using a reference wafer. Furthermore, the management of wafer grid variation caused by the device will be described in detail later.

[0117] In addition, according to the measuring device (100) related to the present embodiment, the control device (60) controls the movement of the slider (10) by the driving system (20) and uses the first position measuring system (30) and the second position measuring system (50) to obtain position information of the slider (10) relative to the platen (12) and relative position information of the mark detection system (MDS) and the platen (12), and also uses the mark detection system (MDS) to obtain position information of a plurality of marks formed on the wafer (W). Accordingly, according to the measuring device (100), position information of a plurality of marks formed on the wafer (W) can be obtained with good precision.

[0118] In addition, according to the measuring device (100) related to the present embodiment, the control device (60) always acquires measurement information (relative position information of the platen (12) and the mark detection system (MDS)) by the second position measuring system (50), and controls the position of the platen (12) in the 6 degrees of freedom direction in real time through three vibration damping devices (14) (actuators) so that the position relationship of the measurement point of the first position measuring system, which detects the position information of the slider (10) in the 6 degrees of freedom direction with respect to the platen (12) and the detection center of the mark detection system (MDS), is maintained at a desired relationship at the nm level. Additionally, the control device (60) controls the driving of the slider (10) by the driving system (20), acquires measurement information (position information of the slider (10) relative to the platen (12)) by the first position measurement system (30) and measurement information (relative position information of the platen (12) and the mark detection system (MDS)) by the second position measurement system (50), and obtains position information of a plurality of wafer marks based on the detection signal when a mark formed on the wafer (W) is detected using the mark detection system (MDS), the measurement information by the first position measurement system (30) obtained when a mark formed on the wafer (W) is detected using the mark detection system (MDS), and the measurement information by the second position measurement system (50) obtained when a mark formed on the wafer (W) is detected using the mark detection system (MDS). Accordingly, according to the measuring device (100), position information of a plurality of marks formed on the wafer (W) can be obtained with good precision.

[0119] In addition, for example, when EGA calculation is not performed using the position information of the measured mark, and position control of the wafer (W) (wafer stage (WST)) described later is performed based on the position information of the measured mark, the measurement information by the second position measurement system (50) described above does not need to be used for the calculation of the position information of the mark. However, in this case, the measurement information by the second position measurement system (50) obtained when a mark formed on the wafer (W) is detected using a mark detection system (MDS) is offset and used to correct information for moving the wafer (W), such as the target value for determining the position of the wafer (W) (wafer stage (WST)). Alternatively, the movement of the reticle (R) (reticle stage (RST) described later during exposure may be controlled by taking into account the offset above.

[0120] In addition, according to the measuring device (100) related to the present embodiment, during alignment measurement, for each of the I (e.g. 98) shots on the wafer (W), position information of at least one wafer mark is measured, and using this position information, the coefficients (a0, a1, …, b0, b1, …) of the above equation (1) are obtained by statistical calculation such as the least squares method. Therefore, it is possible to accurately obtain the deformation components of the wafer grid, including not only linear components but also non-linear components.

[0121] The correction amount of the position coordinates of the shot of the wafer (W) obtained by the measuring device (100) (the coefficients of the above equation (1) (a0, a1, …, b0, b1, …)) is thought to be used for position alignment of the wafer with respect to the exposure position when the wafer (W) is exposed by the exposure device, for example. However, in order to expose the wafer (W) for which the correction amount of the position coordinates has been measured by the measuring device (100) by the exposure device, it is necessary to unload the wafer (W) from the slider (10) and then load it onto the wafer stage of the exposure device. Even if the same type of wafer holder is used, the wafer holder (WH) on the slider (10) and the wafer holder on the wafer stage of the exposure device have different holding states of the wafer (W) due to individual differences in the wafer holders. For this reason, even if the correction amount of the position coordinates of the short of the wafer (W) (coefficients of the above equation (1) (a0, a1, …, b0, b1, …)) is obtained using the measuring device (100), not all of the coefficients (a0, a1, …, b0, b1, …) can be used as is. However, it is thought that the lower-order components (linear components) of the correction amount of the position coordinates of the short, which are affected by the different holding conditions of the wafer (W) for each wafer holder, are of the first order or lower, and the higher-order components of the second order or higher are hardly affected. This is because the higher-order components of the second order or higher are thought to be components that arise mainly from the deformation of the wafer (W) caused by the process, and it is not difficult to think that they are components unrelated to the holding condition of the wafer by the wafer holder.

[0122] Based on this idea, the coefficients of higher-order components (a3, a4, ……, a9, ……, and b3, b4, ……, b9, ……) obtained for the wafer (W) over time by the measuring device (100) can be used as is as the coefficients of higher-order components of the correction amount of the position coordinates of the wafer (W) in the exposure device. Therefore, on the wafer stage of the exposure device, it is sufficient to perform simple EGA measurement (e.g., 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). Since the measuring device (100) is a different device from the exposure device, it is possible to obtain position information of more marks on the substrate without causing a decrease in throughput during the exposure processing of the substrate.

[0123] In addition, if alignment measurement is performed on another wafer using a measurement device (100) in parallel with the wafer processing using the aforementioned simple EGA measurement and exposure device, efficient processing is possible without significantly reducing the throughput of the wafer processing.

[0124] In addition, in the above embodiment, for the sake of simplification of the explanation, either Mode A or Mode B is set as the measurement mode, but it is not limited thereto, and Mode C, which detects two or more first wafer marks for all shots on all wafers in the lot, and Mode D, which detects two or more second wafer marks for some shots, for example, predetermined shots located at the periphery of the wafer, and detects one wafer mark for each of the remaining shots, may be formed. In addition, Mode E, which selects either Mode A, Mode C, or Mode D for the remaining wafers in the lot based on the detection result of wafer marks for the first predetermined number of wafers in the lot, may be formed.

[0125] Also, as a measurement mode of the measurement device (100), for all wafers in the lot, one or more wafer marks of some shots, for example, 90% or 80% of the number of shots, may be measured, or for shots located in the center of the wafer, one or more wafer marks of shots spaced apart may be measured.

[0126] In addition, in the above embodiment, although the case where each of the gratings (RG1, RG2a, RG2b) has the X-axis direction and the Y-axis direction as periodic directions was described, it is not limited to this, and the grating portion (2D grating) provided by each of the first position measuring system (30) and the second position measuring system (50) may have two directions intersecting each other within the XY plane as periodic directions.

[0127] Furthermore, the configuration of the head portion (32) of the first position measurement system (30) described in the above embodiment, and the arrangement of the detection points, etc., are merely examples. For instance, the detection point of the mark detection system (MDS) and the detection center of the head portion (32) do not need to coincide in at least one of the X-axis direction and the Y-axis direction. Also, the arrangement of the head portion of the first measurement system (30) and the grating (RG1) (grid portion) may be opposite. That is, the head portion may be formed on the slider (10) and the grating portion may be formed on the surface plate (12). Also, the first position measurement system (30) does not necessarily need to be equipped with an encoder system (33) and a laser interferometer system (35), and the first position measurement system (30) may be configured using only the encoder system. A first position measurement system may be configured by an encoder system that irradiates a beam from the head unit onto the grating (RG1) of the slider (10), receives a return beam (diffracted beam) from the grating, and measures the position information of the slider (10) in the 6 degrees of freedom direction relative to the platen (12). In this case, the configuration of the head of the head unit does not particularly matter. For example, a pair of XZ heads that irradiate a detection beam to two points equidistant in the X-axis direction relative to a predetermined point on the grating (RG1) and a pair of YZ heads that irradiate a detection beam to two points equidistant in the Y-axis direction relative to the predetermined point may be formed, or a pair of 3D heads that irradiate a detection beam to each of two points equidistant in the X-axis direction relative to the grating (RG1) may be formed, and XZ heads or YZ heads that irradiate a detection beam to points that are different in position in the Y-axis direction relative to the two points may be formed. The first position measuring system (30) does not necessarily need to be able to measure position information in the 6 degrees of freedom directions of the slider (10) relative to the platen (12), and may only be able to measure position information in the X, Y, and θz directions, for example.Additionally, a first position measuring system for measuring position information of the slider (10) relative to the plate (12) may be placed between the plate (12) and the slider (10).

[0128] Likewise, the configuration of the second position measurement system (50) described in the above embodiment is merely an example. For example, the head portions (52A, 52B) may be fixed to the side of the platen (12), and the scales (54A, 54B) may be formed integrally with the mark detection system (MDS). Also, although the case where the second measurement system (50) is equipped with a pair of head portions (52A, 52B) has been exemplified, it is not limited to this, and the second measurement system (50) may be equipped with only one head portion or with three or more. In either case, it is preferable that the second position measurement system (50) can measure the positional relationship of the platen (12) and the mark detection system (MDS) in the six degrees of freedom directions. However, the second measurement system (50) does not necessarily have to be able to measure all positional relationships in the six degrees of freedom directions.

[0129] Additionally, in the above embodiment, a case was described in which a slider (10) is supported by floating on a platen (12) by a plurality of air bearings (18), and a drive system (20) is configured to drive the slider (10) in a non-contact state with respect to the platen (12), comprising 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). However, this is not limited to this, and as the drive system (20), a drive system configured to drive the slider (10) in six degrees of freedom directions on the platen (12) may be adopted. As an example, such a drive system may be configured by a magnetic levitation type planar motor. In this case, air bearings (18) are not required. In addition, the measuring device (100) may be equipped with a driving system that drives the platen (12) separately from the vibration damping device (14).

[0130] In addition, a configuration may be adopted in which the slider (10) can be driven in the X, Y, and θz directions relative to the platen (12) by a magnetic levitation or air levitation type planar motor, and in that case, the aforementioned second position measuring system (50) does not necessarily have to be formed.

[0131] 《Second Embodiment》

[0132] Next, a second embodiment of a lithography system including the measuring device (100) described above will be explained based on FIGS. 8 to 10.

[0133] The lithography system (1000) related to the second embodiment comprises an exposure device (200), a measuring device (100), and a substrate processing device (300) connected in-line to each other, as shown in FIG. 8. Here, since a coater developer (C / D) is used as the substrate processing device (300), it will also be appropriately referred to as C / D (300) below. The lithography system (1000) is installed in a clean room.

[0134] In a conventional lithography system, for example as disclosed in U.S. Patent No. 6,698,944, an inline interface unit is disposed having a wafer transport system inside the chamber to connect the two inline between an exposure device and a substrate processing device (C / D). Meanwhile, as can be seen from FIG. 8, in the lithography system (1000) related to the second embodiment of the present invention, instead of an inline interface unit, a measuring device (100) is disposed between the exposure device (200) and the C / D (300).

[0135] The exposure device (200), C / D (300), and measuring device (100) provided by the lithography system (1000) all have chambers, and the chambers are arranged adjacent to each other. The exposure control device (220) of the exposure device (200), the coating development control device (320) of the C / D (300), and the control device (60) of the measuring device (100) are connected to each other through a local area network (LAN) (500) and communicate between the three parties. A memory device (400) is also connected to the LAN (500).

[0136] The exposure device (200) is, for example, a step-and-scan type projection exposure device (scanner). In FIG. 9, the components inside the chamber of the exposure device (200) are partially omitted.

[0137] As shown in FIG. 9, the exposure device (200) is equipped with 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 sensitizer (resist), a wafer stage (WST) that holds the wafer (W) and moves within the XY plane, and a control system thereof. The exposure device (200) is equipped with 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).

[0138] The illumination system (IOP) includes a light source and an illumination optical system connected to the light source via a transmitting optical system, and illuminates a slit-shaped illumination region (IAR) that extends thinly and elongatedly in the X-axis direction (orientation to the ground in FIG. 9) on a reticle (R) set (limited) by a reticle blind (masking system) with an almost uniform illuminance by an illumination light (exposure light) (IL). The configuration of the illumination system (IOP) is disclosed, for example, in the specification of U.S. Patent Application Publication No. 2003 / 0025890, etc. Here, as an example, ArF excimer laser light (wavelength 193 nm) is used as the illumination light (IL).

[0139] The reticle stage (RST) is positioned below the illumination system (IOP) in FIG. 9. The reticle stage (RST) is driven by a reticle stage drive system (211) (not shown in FIG. 9, see FIG. 10), which includes, for example, a linear motor, so that the reticle stage plate (not shown) can be driven in a microscopic manner within a horizontal plane (XY plane) and driven within a predetermined stroke range in the scanning direction (the Y-axis direction, which is the left-right direction within the plane in FIG. 9).

[0140] On the reticle stage (RST), a reticle (R) is placed, having a pattern area on the -Z side (pattern surface) and a plurality of marks with a known positional relationship to the pattern area. Position information (including rotation information in the θz direction) within the XY plane of the reticle stage (RST) is always detected by a reticle laser interferometer (hereinafter referred to as "reticle interferometer") (214) through a moving mirror (212) (or a reflective surface formed on the cross-section of the reticle stage (RST)) with a resolution of, for example, about 0.25 nm. The measurement information of the reticle interferometer (214) is supplied to an exposure control device (220) (see FIG. 10). Additionally, the position information within the XY plane of the reticle stage (RST) described above may be measured by an encoder instead of the reticle laser interferometer (214).

[0141] A projection unit (PU) is positioned below the reticle stage (RST) in FIG. 9. The projection unit (PU) includes a barrel (240) and a projection optical system (PL) maintained within the barrel (240). The projection optical system (PL) has a predetermined projection magnification (e.g., 1 / 4, 1 / 5, or 1 / 8, etc.), for example, with both sides telecentric. A reticle (R) is positioned so that the first surface (object surface) of the projection optical system (PL) and the pattern surface are nearly aligned, and a wafer (W) with a resist (sensor) applied to its surface is positioned on the second surface (image surface) of the projection optical system (PL). For this reason, when the illumination area (IAR) on the reticle (R) is illuminated by the illumination light (IL) from the illumination system (IOP), a reduced image (a reduced image of a part of the circuit pattern) of the circuit pattern of the reticle (R) within the illumination area (IAR) is formed through the projection optical system (PL) on the area on the wafer (W) conjugated to the illumination area (IAR) (hereinafter also referred to as the exposure area) (IA). Then, by synchronous driving of the reticle stage (RST) and the wafer stage (WST), the reticle (R) is moved relative to the illumination area (IAR) (illumination light (IL)) in the scanning direction (Y-axis direction), and the wafer (W) is moved relative to the exposure area (IA) (illumination light (IL)) in the scanning direction (Y-axis direction), thereby performing scanning exposure of one shot area (partition area) on the wafer (W), and the pattern of the reticle (R) is transferred to the shot area.

[0142] As a projection optical system (PL), a refractometer consisting of multiple refractive optical elements (lens elements), for example, about 10 to 20, arranged along an optical axis (AX) parallel to the Z-axis direction is used. Among the multiple lens elements constituting this projection optical system (PL), the multiple lens elements on the object plane side (reticle (R) side) are movable lenses that can be shifted driven in the Z-axis direction (the optical axis direction of the projection optical system (PL)) and driven in the inclined direction with respect to the XY plane (i.e., the θx direction and the θy direction) by a driving element, for example, a piezo element, which is not shown. In addition, an image characteristic correction controller (248) (not shown in FIG. 9, see FIG. 10) independently adjusts the applied voltage to each driving element based on instructions from the exposure control device (220), thereby driving each movable lens individually and adjusting various image characteristics (magnification, distortion aberration, astigmatism, coma aberration, image plane curvature, etc.) of the projection optical system (PL). Furthermore, instead of moving the movable lens, or in addition to this, a sealed chamber may be formed between adjacent specific lens elements inside the lens barrel (240), and the image characteristic correction controller (248) may control the pressure of the gas inside the sealed chamber, or a configuration may be adopted in which the image characteristic correction controller (248) can shift the center wavelength of the illumination light (IL). By such a configuration, the image characteristics of the projection optical system (PL) can also be adjusted.

[0143] A wafer stage (WST) is driven by a stage drive system (224) (shown as a block for convenience in FIG. 9), which includes a planar motor or a linear motor, etc., to move on a wafer stage plate (222) in the X-axis direction and Y-axis direction with a predetermined stroke, and is also driven in the Z-axis direction, θx direction, θy direction, and θz direction. On the wafer stage (WST), a wafer (W) is held by vacuum suction, etc., through a wafer holder (not shown). In this second embodiment, the wafer holder is configured to be able to hold a 300 mm wafer by suction. In addition, instead of a wafer stage (WST), a stage device may be used that has a first stage that moves in the X-axis direction, Y-axis direction, and θz direction, and a second stage that moves in the Z-axis direction, θx direction, and θy direction on the first stage. In addition, either 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.”

[0144] Position information within the XY plane of the wafer stage (WST) (including rotation information (amount of yawing (amount of rotation in the θz direction θz), a amount of pitching (amount of rotation in the θx direction θx), and a amount of rolling (amount of rotation in the θy direction θy)) is always detected by a laser interferometer system (hereinafter abbreviated as interferometer system) (218) through a moving mirror (216) (or a reflective surface formed on the cross-section of the wafer stage (WST)) with a resolution of, for example, about 0.25 nm. Additionally, position information within the XY plane of the wafer stage (WST) may be measured by an encoder system instead of the interferometer system (218).

[0145] 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) of the wafer stage (WST) within the XY plane through the stage drive system (224).

[0146] Also, although the illustration is omitted in FIG. 9, the position and inclination amount in the Z-axis direction of the wafer (W) surface are measured by a focus sensor (AFS) (see FIG. 10) comprising a light-incident multi-point focus position detection system, for example, as disclosed in U.S. Patent No. 5,448,332. The measurement information of this focus sensor (AFS) is also supplied to an exposure control device (220) (see FIG. 10).

[0147] Additionally, a reference plate (FP) is fixed on the wafer stage (WST), the surface of which is at the same height as the surface of the wafer (W). On the surface of this reference plate (FP), a first reference mark used for baseline measurement of an alignment detection system (AS), and a pair of second reference marks detected by a reticle alignment detection system described later are formed.

[0148] On the side of the tube (240) of the projection unit (PU), an alignment detection system (AS) is formed to detect an alignment mark or a first reference mark formed on a wafer (W). As an alignment detection system (AS), for example, a Field Image Alignment (FIA) system, which is a type of image processing type alignment sensor that illuminates the mark with broadband light such as a halogen lamp and measures the mark position by image processing of the mark, is used. In addition, a diffracted light interferometric alignment system may be used instead of or together with the image processing type alignment detection system (AS).

[0149] In the exposure device (200), additionally, a pair of reticle alignment detectors (213) (not shown in FIG. 9, see FIG. 10) capable of simultaneously detecting a pair of reticle marks located at the same Y position on a reticle (R) placed on the reticle stage (RST) are formed above the reticle stage (RST) at a predetermined distance interval in the X-axis direction. The result of the detection of marks by the reticle alignment detectors (213) is supplied to the exposure control device (220).

[0150] In FIG. 10, the input-output relationship of the exposure control device (220) is shown as a block diagram. As shown in FIG. 10, the exposure device (200) is equipped with, in addition to the above-mentioned components, a wafer transport system (270) for transporting wafers connected to the exposure control device (220). The exposure control device (220) includes a microcomputer or a workstation, etc., and comprehensively controls the entire device including the above-mentioned components. The wafer transport system (270) is, for example, composed of a horizontal multi-joint robot.

[0151] Returning to FIG. 8, the C / D (300), although not explicitly shown, is equipped with, for example, a coating section for applying a sensitizer (resist) to a wafer, a developing section capable of developing the wafer, a baking section for performing a pre-bake (PB) and a post-exposure bake (PEB), and a wafer transport system (hereinafter referred to as the transport system within the C / D for convenience). The C / D (300) is further equipped with a temperature section (330) capable of heating the wafer. The temperature section (330) is typically a cooling section and is equipped with a flat plate (temperature device) called, for example, a cool plate. The cool plate is cooled, for example, by the circulation of cooling water. In addition, electronic cooling based on the Peltier effect may be used.

[0152] The memory device (400) includes a management device connected to a LAN (500) and a storage device connected to the management device via a communication path such as SCSI.

[0153] In the lithography system (1000) related to the second embodiment, the measuring device (100), the exposure device (200), and the C / D (300) are all equipped with a barcode reader (not shown), and during the transport of wafers by each of the wafer transport system (70) (see FIG. 6), the wafer transport system (270) (see FIG. 10), and the transport system within the C / D (not shown), the identification information of each wafer, such as wafer number and lot number, is appropriately read by the barcode reader. For the sake of brevity, the description regarding the reading of identification information of each wafer using the barcode reader is omitted below.

[0154] In a lithography system (1000), a number of wafers are processed sequentially by each of an exposure device (200), a C / D (300), and a measuring device (100) (hereinafter appropriately referred to as three devices (100, 200, 300)). In the lithography system (1000), the entire processing sequence is determined so that the throughput of the system as a whole is maximized, that is, for example, so that the processing time of the device requiring the most time for processing completely overlaps with the processing time of another device.

[0155] Below, the flow of operation for processing multiple wafers continuously by a lithography system (1000) will be described.

[0156] First, a first wafer (let's call it W1) is removed from a wafer carrier placed inside the chamber of the C / D (300) by a conveying system (e.g., a SCARA robot) within the C / D and brought into the coating section. Thereby, the coating of the resist is initiated by the coating section. When the coating of the resist is finished, the conveying system within the C / D removes the wafer (W1) from the coating section and brings it into the baking section. Thereby, the heat treatment (PB) of the wafer (W1) is initiated in the baking section. Then, when the PB of the wafer is finished, the wafer (W1) is removed from the baking section by the conveying system within the C / D and brought into the temperature control section (330). Thereby, the cooling of the wafer (W1) is initiated on a cool plate inside the temperature control section (330). This cooling is performed with the target temperature of the air conditioning system of the exposure device (200), which is set to a temperature that has no effect within the exposure device (200), typically in the range of, for example, 20 to 25°C. Typically, when the wafer is introduced into the temperature control unit (330), the wafer temperature is within the range of ±0.3 [°C] relative to the target temperature, but is heated to the range of ±10 [mK] relative to the target temperature by the temperature control unit (330).

[0157] And, when cooling (heating) in the temperature control unit (330) is finished, the wafer (W1) is placed on the first substrate receiving unit formed between the C / D (300) and the measuring device (100) by the carrier system in the C / D.

[0158] In the C / D (300), the resist coating, PB, cooling, and the transfer operation of the wafer accompanying the series of processes for the same series of wafers as described above are repeated sequentially, and the wafer is sequentially placed on the first substrate receiving section. In addition, in practice, by forming two or more coating sections and a transfer system within the C / D (300) chamber, parallel processing of multiple wafers is possible, thereby enabling a reduction in the time required for pre-exposure processing.

[0159] In the measuring device (100), a wafer (W1) before exposure, which is sequentially placed on the first substrate receiving part by the C / D internal transport system, is loaded onto the slider (10) in the order described in the first embodiment by the joint operation of the wafer transport system (70) and the upper and lower moving member on the slider (10). After loading, the measuring device (100) performs alignment measurement of the wafer in a set measurement mode, and the control device (60) obtains the correction amount of the position coordinates of the shot of the wafer (W) (the coefficient (a0, a1, …, b0, b1, …)) of the above equation (1).

[0160] The control device (60) creates alignment history data (file) by associating the correction amount of the obtained position coordinates (coefficients of the above equation (1) (a0, a1, …, b0, b1, …)), the information of the wafer mark used in the calculation of the correction amount, the information of the measurement mode, and the information of all wafer marks with good detection signals with the identification information of the wafer (W1) (wafer number, lot number), and stores it in the memory device (400).

[0161] After that, the wafer (W1) for which alignment measurement has been completed is placed by the wafer transport system (70) in the load-side substrate placement section of the second substrate receiving section formed near the measuring device (100) inside the chamber of the exposure device (200). Here, the second substrate receiving section has a load-side substrate placement section and an unload-side substrate placement section formed therein.

[0162] Afterwards, in the measuring device (100), alignment measurement, creation of alignment history data (file), and transfer of the wafer are repeated for the second and subsequent wafers in the same order as for the wafer (W1).

[0163] The wafer (W1) placed on the aforementioned loading-side substrate mounting section is transported by the wafer transport system (270) to a predetermined waiting position inside the exposure device (200). However, the first wafer (W1) does not wait at the waiting position but is immediately loaded onto the wafer stage (WST) by the exposure control device (220). The loading of this wafer is carried out by the exposure control device (220) using the wafer transport system (270) and the vertically moving member (not shown) on the wafer stage (WST), in the same manner as carried out by the aforementioned measuring device (100). After loading, search alignment in the same manner as above and an EGA-type wafer alignment in which, for example, 3 to 16 shots are aligned shots are performed on the wafer on the wafer stage (WST) using an alignment detection system (AS). During wafer alignment using this EGA method, the exposure control device (220) of the exposure device (200) searches for an alignment history data file stored in a memory device (400) using identification information (e.g., wafer number, lot number) of the wafer (target wafer) to be aligned and exposed as a key, and obtains the alignment history data of the target wafer. Then, after a predetermined preparation operation, the exposure control device (220) performs the following wafer alignment according to the measurement mode information included in the obtained alignment history data.

[0164] First, the case in which information of Mode A is included is explained. In this case, among the wafer marks included in the alignment history data, the position information is measured by the measuring device (100) (the position information of the mark is used to calculate the correction amount), and a number of wafer marks corresponding to the number of alignment shots are selected and set as detection targets. The wafer marks of the detection targets are detected using an alignment detection system (AS), and based on the detection result 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 wafer mark of the detection targets is obtained, and using the position information, an EGA calculation is performed and each coefficient of the following equation (2) is obtained.

[0165]

[0166] Then, the exposure control device (220) substitutes 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 design position coordinates (X, Y) of each shot in a wafer coordinate system with the center of the wafer as the origin, represented by the following equation (3) containing the coefficients after substitution, to obtain the correction amount (alignment correction component) (dx, dy) of the position coordinates of each shot, and based on this correction amount, determines a target position (hereinafter referred to as the position determination target position) for position alignment with the exposure position (projection position of the reticle pattern) during exposure of each shot to correct the wafer grid. In addition, in this embodiment, exposure is performed using a scanning exposure method rather than a static exposure method, but for convenience, it is referred to as the position determination target position.

[0167]

[0168] In addition, in the exposure device (200), since the rotation of the reference coordinate system (stage coordinate system) and the wafer coordinate system that define the movement of the wafer stage (WST) is canceled by search alignment, there is no need to specifically distinguish between the reference coordinate system and the wafer coordinate system.

[0169] Next, the case where mode B is set is described. In this case, the exposure control device (220) determines the target position for positioning each shot to correct the wafer grid in the same order as in the case of mode A described above. However, in this case, the alignment history data includes a plurality of wafer marks for several shots and one wafer mark for each of the remaining shots, and among them, 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.

[0170] Thus, the exposure control device (220), in addition to determining the positioning target position of each shot described above, selects a number of wafer marks necessary to obtain the shot shape from among a plurality of wafer marks for the several shots, and uses the position information (measured value) of those wafer marks to perform a statistical operation (also called a multi-point EGA operation within the shot) by applying the least squares method to the model equation [Equation 7] disclosed in, for example, U.S. Patent No. 6,876,946, to obtain the shot shape. Specifically, among the 10 parameters of the model equation [Equation 7] disclosed in, U.S. Patent No. 6,876,946, chip rotation (θ), chip orthogonality error (w), and chip scaling in the x direction (rx) and chip scaling in the y direction (ry) are obtained. In addition, regarding multi-point EGA operations within a short, a detailed description is omitted as they are disclosed in detail in the aforementioned U.S. patent.

[0171] Then, the exposure control device (220) performs exposure on each shot on the wafer (W1) in a step-and-scan manner while controlling the position of the wafer stage (WST) according to the position determination target position. Here, if the shot shape is also obtained by multi-point EGA measurement within the shot, during scanning exposure, at least one of the relative scanning angle of the reticle stage (RST) and the wafer stage (WST), the scanning speed ratio, the relative position of at least one of the projection optical system of the reticle stage (RST) and the wafer stage (WST) with respect to the projection optical system, the imaging characteristic (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) 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 center wavelength of the illumination light (IL) are carried out by the exposure control device (220) through the imaging characteristic correction controller (248).

[0172] In parallel with the EGA wafer alignment and exposure being performed on the wafer (in this case, wafer (W1)) on the wafer stage (WST) above, the wafer alignment measurement in a set mode and the creation of alignment history data are performed on the second wafer (let's call it wafer (W2)) by the measuring device (100) in the order described above.

[0173] Then, before the exposure of the wafer (in this case, wafer (W1)) on the wafer stage (WST) is finished, the measurement processing of the measurement device (100) is finished, and the second wafer (W2) is placed on the load-side substrate placement section by the wafer transport system (70), and is transported by the wafer transport system (270) to a predetermined waiting position inside the exposure device (200), and waits at that waiting position.

[0174] Then, when the exposure of the wafer (W1) is finished, the wafer (W1) and the wafer (W2) are exchanged on the wafer stage, and the same wafer alignment and exposure as described above are performed on the wafer (W2) after the exchange. In addition, if the transport of the wafer (W2) to the waiting position is not finished until the exposure of the wafer (in this case, wafer (W1)) on the wafer stage is finished, the wafer stage waits near the waiting position while holding the wafer that has finished exposure.

[0175] In parallel with the wafer alignment for the wafer (W2) after the exchange above, the wafer (W1) that has finished exposure is returned to the unload side substrate placement section of the second substrate receiving section by the wafer transport system (270).

[0176] After this, the wafer transport system (70) performs the operation of transporting and placing the wafer that has finished exposure from the unload side substrate placement section to the first substrate receiving section in parallel with the wafer alignment measurement being performed by the measuring device (100) as described above, and the operation of taking out the wafer that has not been exposed after the measurement is finished from the slider (10) and transporting it to the load side substrate placement section in a predetermined order.

[0177] As described above, the exposed wafer that has been transported and placed on the first substrate receiving section by the wafer transport system (70) is brought into the bake section by the transport system within the C / D, and PEB is performed by the baking device in the bake section. Multiple wafers can be accommodated simultaneously in the bake section.

[0178] Meanwhile, the wafer from which the PEB has finished is removed from the bake section by a transport system within the C / D and introduced into the developing section, and development is initiated by a developing device within the developing section.

[0179] Then, when the development of the wafer is finished, the wafer is removed from the development section by a transport system within the C / D and brought into a designated storage section within the wafer carrier. Afterwards, within the C / D (300), for the second and subsequent wafers after the exposure is finished, PEB, development, and wafer transport are repeated in the same order as wafer (W1).

[0180] As described above, according to the lithography system (1000) related to the second embodiment, alignment measurement of a wafer can be performed by a measuring device (100) in parallel with the operation of an exposure device (200), and an entire shot EGA in which the entire shot is a sample shot can be performed in parallel with the wafer alignment and exposure operation of the exposure device (200). In addition, since the coefficients of the higher-order components in the model equation obtained from the entire shot EGA can be adopted as is in the exposure device (200), the exposure device (200) only needs to perform alignment measurement with several shots as alignment shots to obtain the coefficients of the lower-order components of the above model equation, and by using these coefficients of the lower-order components and the coefficients of the higher-order components obtained from the measurement device (100), it becomes possible to calculate the target position for position determination during exposure of each shot with the same good precision as when the coefficients of the lower and higher-order components of the model equation (1) are obtained in the exposure device (200). Therefore, it is possible to improve the superposition precision of the pattern image of the reticle during exposure and the pattern formed in each shot area on the wafer without reducing the throughput of the exposure device (200).

[0181] In addition, in the lithography system (1000) related to the second embodiment above, the exposure device (200) has obtained coefficients of lower-order components of the model equation of the first order or lower, and has described a case where these coefficients of lower-order components and coefficients of higher-order components of the model equation of the second order or higher obtained from the measuring device (100) are used. However, this is not limited to this, and for example, coefficients of lower-order components of the model equation of the second order or lower may be obtained from the detection result of alignment marks within the exposure device (200), and these coefficients of lower-order components and coefficients of higher-order components of the model equation of the third order or higher obtained from the measuring device (100) may be used. Alternatively, for example, coefficients of lower-order components of the model equation of the third order or lower may be obtained from the detection result of alignment marks within the exposure device (200), and these coefficients of lower-order components and coefficients of higher-order components of the model equation of the fourth order or higher obtained from the measuring device (100) may be used. That is, the coefficient of the component of the above model formula of order (N - 1) (N is an integer greater than or equal to 2) or lower is obtained from the detection result of the alignment mark in the exposure device (200), and the coefficient of the component of order (N - 1) or lower and the coefficient of the higher-order component of the above model formula of order N or higher obtained from the measuring device (100) may be used.

[0182] In addition, in the lithography system (1000), if the measurement unit (40) of the measurement device (100) is equipped with the aforementioned multi-point focus position detection system, the flatness measurement (also called focus mapping) of the wafer (W) may be performed together with the wafer alignment measurement by the measurement device (100). In this case, by using the result of the flatness measurement, the focus leveling control of the wafer (W) during exposure is possible without performing flatness measurement by the exposure device (200).

[0183] In addition, in the second embodiment above, the target is a 300 mm wafer, but it is not limited to this and 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 if it is a 450 mm wafer, it is possible to perform, for example, full-point EGA measurement without causing a decrease in the throughput of the exposure process.

[0184] Additionally, although omitted, in a lithography system (1000), an exposure device (200) and a C / D (300) may be connected in-line, and a measuring device (100) may be placed on the opposite side of the exposure device (200) of the C / D (300). In this case, the measuring device (100) may be used for alignment measurement (hereinafter referred to as pre-measurement) identical to the above, for example, targeting a wafer before resist coating. Alternatively, the measuring device (100) may be used for position misalignment measurement of an overlapping misalignment measurement mark (overlapping misalignment measurement) for a wafer after development is finished, or it may be used for both pre-measurement and overlapping misalignment measurement.

[0185] Wafer Grid Variation Management

[0186] Next, a method for managing a wafer grid originating from an exposure device using a measuring device (100) is explained as an example when applied to a lithography system (1000). FIG. 11 schematically shows the flow of processing in the method for managing a wafer grid in this case.

[0187] First, in step S202, exposure is performed on a bare wafer (for convenience, referred to as wafer (W0)) by an exposure device (200) using a product reticle (R) in a step-and-scan manner. Here, the reticle (R) is configured to have a rectangular pattern area on its pattern surface, along with a mark (which becomes a wafer mark when transferred onto the wafer) formed in the surrounding area or inside the pattern area (in the case of acquiring multiple chips in one shot). Here, the wafer (W0) is an unexposed wafer, and a resist is applied to its surface by a C / D (300). Therefore, during the exposure of the wafer (W0), alignment is not performed, and the reticle stage (RST) and wafer stage (WST) are driven and controlled by an exposure control device (220) based on design values. By exposure in this step S202, a transfer image (latent image) of a mark corresponding to each shot, in which the positional relationship between each shot and the square pattern area (e.g. 98) arranged on the matrix is ​​already known in the design, is formed on the resist layer on the surface of the wafer (W0).

[0188] Next, in step S204, the wafer (W0) that has finished exposure is unloaded from the wafer stage (WST) and brought into the developing section of the C / D (300). Specifically, the wafer (W0) is transported by the wafer transport system (270) and the wafer transport system (70) and placed on the first substrate receiving section formed between the C / D (300) and the measuring device (100). Then, the wafer (W0) is brought into the developing section of the C / D (300) by the transport system within the C / D.

[0189] Next, in step S206, the wafer (W0) is developed by a developing device of the developing section of the C / D (300). After this development, on the wafer (W0), a resist image (hereinafter appropriately abbreviated as wafer mark) is formed, in which I (e.g. 98) square shots arranged in a matrix and the positional relationship of each shot is already known in the design and each shot corresponds to a wafer mark.

[0190] Next, in step S208, the wafer (W0) that has finished developing is removed from the C / D (300) and loaded onto the slider (10) of the measuring device (100). Specifically, the wafer (W0) is removed from the developing section by a conveying system within the C / D and placed on the first substrate receiving section. Then, the wafer (W0) is conveyed from the first substrate receiving section to the upper side of the slider (10) in the loading position by the wafer conveying system (70) of the measuring device (100) and loaded onto the slider (10).

[0191] Next, in step S210, the control device (60) performs the aforementioned total shot point measurement on the wafer (W0) that has finished developing, and obtains the absolute position coordinates of each wafer mark. That is, the control device (60) measures the position information of the slider (10) using the first position measurement system (30) (and the second position measurement system (50)), and uses the mark detection system (MDS) to detect each of the I wafer marks corresponding to each of the I (e.g., 98) shots, and obtains the absolute position coordinates (X, Y) of the I wafer marks corresponding to each of the I shots on the wafer (W0) based on the detection result of each of the I wafer marks and the absolute position coordinates (X, Y) of the slider (10) at the time of detection of each of the I wafer marks. At this time, the control device (60) obtains the absolute position coordinates (X, Y) of I wafer marks by using the X-axis and Y-axis direction Abbe error of the first position measurement system (30) and the X-axis and Y-axis direction measurement value of the second position measurement system (50) as offsets, based on the measurement values ​​of the slider (10) in the θx and θy directions measured by the first measurement system (30).

[0192] Next, in step S212, the control device (60) obtains information on the variation of the arrangement (wafer grid) of I shots on the wafer (W0) using the absolute position coordinates of I shots obtained by the control device (60). For example, the control device (60) obtains the measured value of the absolute position coordinate (XY) of each of the I shots from the absolute position coordinates of the I wafer marks based on the already known positional relationship between the wafer marks and the center of the shots, and obtains the coefficients (a0, a1, …, b0, b1, …) of the aforementioned equation (1) by using statistical operations such as the least squares method based on the data of the difference between the measured value of the absolute position coordinate (XY) of each of the I shots and the design value of the position coordinate (XY) of each shot. Here, the calculated coefficients (a0, a1, …, b0, b1, …) are substituted into Equation (1), and the Equation (1) after the coefficients are determined is stored in an internal memory (or memory device (400)) as the wafer grid variation information.

[0193] Alternatively, the control device (60) may obtain the actual value of the absolute position coordinate (XY) of each of the I shots from the absolute position coordinates of the I wafer marks based on the known positional relationship between the wafer marks and the shot center, create a map consisting of the data of the difference between the actual value of the absolute position coordinate (XY) of each of the I shots and the design value of the position coordinate (XY) of each shot, and store this map in memory (or storage device (400)) as wafer grid variation information.

[0194] Thus, it becomes possible to calculate the amount of variation from the wafer grid design value at any time and manage that amount of variation.

[0195] The following step S214 is performed as necessary. In step S214, the control device (60) compares the variation information from the wafer grid design value obtained in step S210 with the variation information of a reference wafer grid that is previously stored in memory (or storage device (400)), and calculates the amount of variation of the wafer grid from the variation of the reference wafer grid. By processing this step S214, it becomes possible to manage the shot arrangement error caused by the error in the stage grid between different exposure devices, or the shot arrangement error caused by the error in the stage grid between different time points of the same exposure device.

[0196] In the former case, prior to the processing of step S214, exposure is performed on a bare wafer different from the wafer (W0) using a scanning stepper different from the exposure device (200) in the same manner as the aforementioned step S202, and on the wafer that has been exposed, processing in the same manner as steps S204 to S212 is performed so that information on the variation of the reference wafer grid is obtained and stored in memory (or storage device (400)).

[0197] In the latter case, prior to the processing of step S214, the same processing as steps S202 to S208 is performed on a wafer different from wafer (W0) so that information on the variation of the reference wafer grid is obtained and stored in memory (or storage device (400)).

[0198] As is evident from the description above, the management method related to the present embodiment can manage variations in the wafer grid caused by the device without using a reference wafer. Therefore, it is possible to avoid the following problems that occur when a reference wafer is used.

[0199] In other words, operation using a reference wafer becomes a competition for resources because the reference wafer is reused in multiple exposure devices. Since reference wafers are typically manufactured in multiple copies rather than just one, it is necessary to ensure individual differences between them. Additionally, reference wafers may break or degrade during use. Furthermore, in the management method for wafer grids using reference wafers, a resist is applied to the surface of the reference wafer for exposure, and after the necessary processing is completed, the resist is peeled off to clean the reference wafer. Repeating this process can sometimes damage the surface. Moreover, marks from chuck components (such as pin chucks) of the wafer holder remain on the back side of the reference wafer, causing adsorption deformation of the reference wafer and deforming the wafer grid.

[0200] Meanwhile, by not using a reference wafer, the following advantages are available.

[0201] a. When measuring (performing correction) variations in the wafer grid without regard to the beam or serial number of the reference wafer, measurement (correction) can be performed.

[0202] b. Since bare wafers can be used instead of reference wafers, quality control can be easily implemented.

[0203] c. Wafer grid management becomes possible using product short maps and product reticles. In other words, it becomes possible to manage the wafer grid by utilizing the overlay measurement marks or alignment marks assigned to the product reticle. As a result, a dedicated reticle for quality control is no longer required. Furthermore, quality control can be performed using the product short map itself; additionally, since it is possible to measure not only location-dependent errors but also the amount of wafer grid variation caused by scan speed, acceleration, and all other error factors arising from the product exposure operation, it becomes possible to eliminate all types of compromises described earlier by performing corrections based on these measurement results.

[0204] In the lithography system (1000) related to the second embodiment, for example, if the throughput of the entire wafer processing of the lithography system (1000) is not reduced more than necessary, the wafer that has finished developing may be loaded onto the slider (10) of the measuring device (100) again in the same order as the wafer before exposure after the aforementioned PB, and the positional misalignment of the overlapping misalignment measuring mark (e.g., box-in-box mark, etc.) formed on the wafer may be measured. That is, since the measuring device (100) can measure the absolute value of the mark on the wafer (on the reference coordinate system by the first position measuring system (30), it is desirable not only as a measuring device for wafer alignment measurement but also as a measuring device for measuring the positional misalignment of the overlapping misalignment measuring mark, which is a type of relative position measurement.

[0205] Superposition Measurement

[0206] Next, an overlapping measurement method using a measuring device (100) is explained as an example when applied to a lithography system (1000). FIG. 12 schematically shows the flow of processing in the overlapping measurement method in this case.

[0207] First, in step S302, in the coating portion of the C / D (300), a wafer (wafer (W) in which the first layer (underlayer) is exposed by an exposure device different from the exposure device (200), such as a scanner or a stepper. 11 The resist is applied to the wafer (W) before the resist application. 11 In the case of the wafer mark and the first mark for overlap misalignment measurement (more precisely, the resist image of the first mark (appropriately also referred to as the first mark image)) are formed corresponding to each shot, along with a plurality of, for example, I shots (I is, for example, 98), by exposure of the underlayer. In this case, the design positional relationship of each of the I first mark images is also known.

[0208] Next, in step S304, the wafer (W) coated with resist 11 ) undergoes the same predetermined processing steps as the aforementioned wafer (W1) and is loaded onto the wafer stage (WST) of the exposure device (200). Specifically, the wafer (W 11 After heat treatment (PB) in the bake section, temperature control in the temperature control section (330), and alignment measurement by the measuring device (100) (here, measurement in A mode) are performed, the wafer is loaded onto the wafer stage (WST).

[0209] Next, in step S306, by the exposure control device (220) of the exposure device (200), the wafer (W) on the wafer stage (WST) 11 Regarding ), an alignment detection system (AS) is used to perform search alignment identical to that of the tactical method, and wafer alignment using the EGA method, with, for example, 3 to 16 shots as alignment shots.

[0210] Next, in step S308, the correction amount (alignment correction component) (dx, dy) of the position coordinates of each shot represented by the aforementioned equation (3) is obtained by the exposure control device (220) based on the result of wafer alignment, and based on this correction amount, the target position for position determination during exposure of each shot is determined for correcting the wafer grid.

[0211] Next, in step S310, while positioning the wafer stage (WST) according to the positioning target position by the exposure device (200), the wafer (W 11 For each shot on the ), exposure of the second layer (an upper layer having the first layer as the lower layer) is performed using a step-and-scan method. At this time, the exposure device (200) is a wafer (W 11 A reticle (for convenience, reticle (R) having a second mark formed corresponding to a first mark image on it 11 Exposure is performed using ). Therefore, by the exposure of this second layer, the wafer (W 11 For I shots on ) Reticle (R 11 Along with the pattern area of ​​) being superimposed and transferred, a transfer image of I second marks is formed, which is arranged in a positional relationship corresponding to the positional relationship of I first marks.

[0212] Next, in step S312, the wafer (W) for which the exposure of the second layer has been completed. 11 ) undergoes the same processing as the aforementioned exposed wafer (W1) and is introduced into the developing section of the C / D (300). Specifically, the wafer (W 11The wafer (W) is returned to the unload-side substrate placement section of the second substrate receiving section by the wafer transport system (270), returned from the unload-side substrate placement section to the first substrate receiving section by the wafer transport system (70), brought into the bake section of the C / D (300) by the transport system within the C / D, and PEB is performed by the baking device within the bake section. The wafer (W) after the PEB is completed 11 ) is taken out of the bake section by the conveying system within the C / D and brought into the developing section.

[0213] Next, in step S314, a wafer (W) in which a transfer image of a plurality of second marks is formed by a developing device within the developing section. 11 ) is developed. Due to this phenomenon, the wafer (W 11 On the ) set of 1 second mark images corresponding to the first mark image is formed with 1 shots together in a predetermined positional relationship and becomes a substrate to be measured during superposition measurement. That is, in this way, a substrate to be measured during superposition measurement (substrate to be measured during superposition measurement) is manufactured. Here, as a set of second mark images corresponding to the first mark image, for example, a resist image of a box-in-box mark consisting of an outer box mark and an inner box mark placed inside it can be used.

[0214] Next, in step S316, the wafer (W) that has finished developing 11 ) (substrate of the superimposed measurement target) is ejected from the developing section by a carrier system within the C / D and placed on the first substrate receiving section.

[0215] Next, in step S318, the wafer (W) that has finished developing and is placed on the first substrate receiving portion is controlled by the control device (60) of the measuring device (100). 11) (substrate to be superimposed for measurement) is loaded onto the slider (10) in the order described above, and the absolute position coordinates within the XY plane of each of the first mark image and the second mark image of the I set can be obtained as follows. That is, the control device (60) measures the position information of the slider (10) using the first position measurement system (30) (and the second position measurement system (50)), and uses the mark detection system (MDS) to measure the wafer (W 11 ) detects the first mark image and the second mark image of set I respectively, and based on the detection results of the first mark image and the second mark image of set I respectively and the absolute position coordinates (X, Y) of the slider (10) at the time of detection of each mark image, the wafer (W 11 The absolute position coordinates within the XY plane of each of the first mark image and the second mark image of the set of I are obtained. At this time, the control device (60) obtains the absolute position coordinates within the XY plane of each of the first mark image and the second mark image of the set of I by using the X-axis direction and Y-axis direction Abbe error of the first position measurement system (30) and the X-axis direction and Y-axis direction measurement value of the second position measurement system (50) as offsets, based on the measurement values ​​of the slider (10) in the θx direction and θy direction measured by the first measurement system (30).

[0216] Next, in step S320, the control device (60) calculates the overlap error (overlap misalignment) between the first layer and the second layer based on the absolute position coordinates of the first mark image and the second mark image that form a set with each other.

[0217] Next, in step S322, the control device (60) determines, based on the absolute position coordinates of I first mark images and the absolute position coordinates of I second mark images, whether the overlap error is mainly caused by the exposure of the first layer or the exposure of the second layer, for example, as follows. That is, the control device (60) determines the amount of deviation (ΔX1) from the design position coordinates of the absolute position coordinates of the first mark images. i , ΔY1 i ) (i = 1 ∼ I) and the amount of deviation (ΔX2) of the absolute position coordinates of the second mark image from the design position coordinates. i , ΔY2 i Calculate ) (i = 1 ∼ I), and ΔX1 i , ΔX2 i , ΔY1 i , ΔY2 i For each, the sum of i = 1 ∼ I ΣX1 i , ΣX2 i , ΣY1 i , ΣY2 i Calculate . And, the control device (60) is ΣX1 i ΣX2 i Also ΣY1 i ΣY2 i In this case, the overlap error is determined to be primarily caused by the exposure of the first layer in either the X-axis direction or the Y-axis direction, and ΣX1 i < ΣX2 i Also ΣY1 i < ΣY2 i In this case, the overlap error is determined to be mainly caused by the exposure of the second layer in either the X-axis direction or the Y-axis direction. Also, the control device (60) is ΣX1 i ΣX2 i Also ΣY1 i < ΣY2 iIn this case, it is determined that the overlap error is mainly caused by the exposure of the first layer in the X-axis direction and mainly caused by the exposure of the second layer in the Y-axis direction, and ΣX1 i < ΣX2 i Also ΣY1 i ΣY2 i In this case, the overlap error is determined to be mainly caused by the exposure of the second layer in the X-axis direction and mainly caused by the exposure of the first layer in the Y-axis direction.

[0218] In addition, the above method of judgment is an example, and the point is that if the control device (60) determines whether the overlap error is mainly caused by the exposure of the first layer or the exposure of the second layer based on the absolute position coordinates of the first mark images and the absolute position coordinates of the second mark images, the specific method of judgment does not particularly matter.

[0219] As is evident from the description above, according to the superposition measurement method related to the present embodiment, the control device (60) of the measurement device (100) can measure the absolute position coordinates of the first mark image and the absolute position coordinates of the second mark image, respectively, and based on these absolute position coordinates, can determine whether the superposition error is mainly caused by the exposure of the lower layer or mainly caused by the exposure of the upper layer, thereby obtaining an excellent effect that is unprecedented.

[0220] In addition, although the above description explains cases where the exposure device used for the exposure of the lower layer and the exposure device used for the exposure of the upper layer are different, it is not limited to this, and even when the exposure of the lower layer and the upper layer is performed by, for example, an exposure device (200), the overlap precision can be managed with high precision by the series of processes described above in steps S302 to S322.

[0221] In addition, in step S320 above, since the overlap error (overlap misalignment) of the first layer and the second layer is calculated, step S322 can be executed as needed.

[0222] In addition, in the lithography system (1000) of FIG. 8, only one measuring device (100) is formed, but as in the following modified example, multiple measuring devices, for example, two, may be formed.

[0223] Variation Example

[0224] FIG. 13 schematically shows the configuration of a lithography system (2000) related to a modified example. The lithography system (2000) is equipped with an exposure device (200), a C / D (300), and two measuring devices (100a, 100b) configured in the same way as the measuring device (100) described above. The lithography system (2000) is installed in a clean room.

[0225] In the lithography system (2000), two measuring devices (100a, 100b) are arranged in parallel between the exposure device (200) and the C / D (300).

[0226] The exposure device (200), C / D (300), and measuring device (100a, 100b) provided by the lithography system (2000) are arranged with chambers adjacent to each other. The exposure control device (220) of the exposure device (200), the coating development control device (320) of the C / D (300), and the control device (60) of each of the measuring devices (100a, 100b) are connected to each other via a LAN (500) and communicate with each other. A memory device (400) is also connected to the LAN.

[0227] In the lithography system (2000) related to this variant example, since it is possible to set the same operation sequence as the aforementioned lithography system (1000), an effect equivalent to that of the lithography system (1000) can be obtained.

[0228] In addition, in the lithography system (2000), it is possible to employ a sequence in which the measurement devices (100a, 100b) are both used for alignment measurement targeting the wafer after the aforementioned PB (hereinafter referred to as post-measurement) and for the same alignment measurement targeting the wafer before the resist coating (pre-measurement). In this case, the pre-measurement targeting a particular wafer is performed in parallel with the aforementioned series of wafer processing targeting a wafer different from that wafer, so the throughput of the entire system is hardly reduced. However, for the first wafer, the time for the pre-measurement cannot be overlapped with the time for the series of wafer processing.

[0229] By comparing the position measured by prior measurement and the position measured by subsequent measurement for the same wafer mark on the same wafer, the position measurement error of the wafer mark caused by the resist coating can be obtained. Accordingly, by correcting the position of the same wafer mark measured during wafer alignment targeting the same wafer by the exposure device (200) by the amount of the wafer mark position measurement error caused by the resist coating obtained above, high-precision EGA measurement is possible by canceling the measurement error of the wafer mark position caused by the resist coating.

[0230] In this case, since the measurement result of the wafer mark position in either the pre-measurement or the post-measurement is affected by the holding condition of the wafer holder, it is preferable to adopt a sequence in which the pre-measurement and the post-measurement are performed on the same wafer by the same measuring device (100a or 100b).

[0231] However, one of the measuring devices (100a and 100b) may be used exclusively for pre-measurement and the other for post-measurement. In this case, at the start of each of the measuring devices (100a and 100b), a reference wafer is mounted on each slider (10), and while measuring the position of the slider (10) with the first position measuring system (30), a mark on the reference wafer is detected by a mark detection system (MDS), and based on the detection result, the grid of the reference wafer is obtained by each of the measuring devices (100a and 100b) in the same way as in the case of the wafer (W0) described above. In this case, as the reference wafer, a wafer may be used in which a mark (which may be any of a line and space mark, a two-dimensional well mark, and a box mark) that can be measured at the resolution of the mark detection system (MDS) is formed on the entire surface by etching, etc., at a specific pitch, for example, a pitch of 1 mm.

[0232] Then, the coordinate systems of each first position measurement system (30) are aligned so that the difference between the grids of the obtained reference wafers disappears. This is because, since the grids of the same reference wafers are fundamentally identical, if there is an error between the grids of the obtained reference wafers, the cause is that there is an error between the reference coordinate systems that define the movement of the slider (10) of each measurement device (100a, 100b).

[0233] In this case, since the reference wafer is required for the calibration between coordinate systems that define the movement of the slider of the measuring device, it is needed only at the start of each measuring device; therefore, the number and frequency required are overwhelmingly smaller compared to conventional technology. Furthermore, it is sufficient to simply measure the marks on the reference wafer with each measuring device, and there is no need to perform exposure on the reference wafer. In other words, since the resist is not applied or peeled off, the reference wafer is not damaged. The reference wafer only needs to be carefully stored as a prototype. Additionally, once each measuring device has started, the reference wafer is, in principle, unnecessary.

[0234] In the lithography system (2000), instead of the prior measurement described above, the aforementioned superimposed misalignment measurement may be performed on the wafer after development is finished. In this case, one of the measurement devices (100a and 100b) may be dedicated to the aforementioned post-measurement, and the other may be dedicated to the superimposed misalignment measurement. Alternatively, for the same wafer, a sequence may be adopted in which the post-measurement and the superimposed misalignment measurement are performed by the same measurement device (100a or 100b). In the latter case, for the same wafer, the prior measurement may also be performed by the same measurement device.

[0235] Although omitted, in the lithography system (2000), one of the measuring devices (100a and 100b), for example, the measuring device (100a), may be placed on the opposite side of the exposure device (200) of the C / D (300). In this case, the measuring device (100a) is suitable for performing the aforementioned overlapping misalignment measurement on the wafer after development is finished, considering the flow of wafer transport. Additionally, if the individual difference in the holder holding state between the measuring devices (100a, 100b) is not a problem, the measuring device (100a) may be used for preliminary measurement instead of overlapping misalignment measurement, or may be used for both overlapping misalignment measurement and preliminary measurement.

[0236] In addition, three or more measuring devices (100) may be formed in addition to the exposure device (200) and C / D (300), and all devices may be connected inline, and two of the three measuring devices (100) may be used for pre-measurement and post-measurement, and the remaining one measuring device may be used exclusively for superposition misalignment measurement. The former two may each be used exclusively for pre-measurement and post-measurement.

[0237] In addition, in the second embodiment and the modified example above, a signal processing device (49) that processes the detection signal of the mark detection system (MDS) provided by the measurement device (100, 100a, 100b) sends only the measurement results of wafer marks with good waveforms of the detection signal obtained as a detection result of the mark detection system (MDS) to the control device (60), and as a result of the EGA calculation being performed by the control device (60) using the measurement results of those wafer marks, the exposure control device (220) has described a case in which the EGA calculation is performed using part of the position information of the wafer marks selected from among a plurality of wafer marks with good waveforms of the detection signal obtained as a detection result by the mark detection system (MDS). However, it is not limited to this, and 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 signal obtained as a detection result of the mark detection system (MDS), to the control device (60). Additionally, the control device (60) may perform the determination of whether the detection signal obtained as a detection result by the mark detection system (MDS) is good, instead of the signal processing device. In this case, the control device (60) performs the aforementioned EGA calculation using only the measurement results of the remaining wafer marks, excluding the wafer mark for which the detection signal is determined to be good or the wafer mark for which the detection signal is determined to be defective. Furthermore, it is preferable for the exposure control device (220) to perform the aforementioned EGA calculation using the measurement results of a portion of the wafer marks selected from the measurement results of the wafer marks used in the EGA calculation by the control device (60).

[0238] Additionally, in the above second embodiment and variant, the case in which the measuring device (100, 100a, 100b) is placed between the exposure device (200) and the C / D (300) instead of the inline interface part was exemplified, but is not limited thereto, and the measuring device (100, 100a, 100b) may be part of the exposure device. For example, it may be installed in the receiving part of the exposure device (200) where the wafer before exposure is introduced. Also, when the measuring device (100, 100a, 100b) is installed inside the chamber of the exposure device (200) as part of the exposure device (200), the measuring device may or may not have a chamber. In addition, when the measuring device (100, 100a, 100b) is part of the exposure device, the measuring device may be equipped with a control device, or it may not be equipped with a control device and be controlled by the control device of the exposure device. In either case, the measuring device is connected inline to the exposure device.

[0239] In addition, although the above embodiment describes the case where the substrate processing device is C / D, the substrate processing device is sufficient if it is a device connected inline to the exposure device and the measuring device, and it may be a coating device (coater) that applies a sensitizer (resist) on a substrate (wafer) or a developing device (developer) that develops the substrate (wafer) after exposure, or it may be a coating device (coater) and a developing device (developer) that are connected inline to the exposure device and the measuring device, respectively.

[0240] If the substrate processing device is a coating device (coater), the measuring device may be used for only the aforementioned post-measurement or for both pre-measurement and post-measurement. In this case, the wafer after exposure is fed into a developing device that is not in-line connected to the exposure device.

[0241] If the substrate processing device is a developing device (developer), the measuring device may be used for only the aforementioned post-measurement or for post-measurement and superposition misalignment measurement. In this case, a wafer with a resist applied in advance at another location is introduced into the exposure device.

[0242] In the above second embodiment and the above modified example (hereinafter referred to as the second embodiment, etc.), the case where the exposure device is a scanning stepper was described, but it is not limited thereto. The exposure device may be a stationary exposure device such as a stepper, or a step-and-stitch type reduction projection exposure device that combines shot areas and shot areas. In addition, the second embodiment, etc. can also be applied to a multi-stage type exposure device equipped with a plurality of wafer stages, as disclosed, for example, in U.S. Patent No. 6,590,634, U.S. Patent No. 5,969,441, U.S. Patent No. 6,208,407, etc. In addition, the exposure device is not limited to a dry-type exposure device that performs exposure of a wafer (W) without passing through the aforementioned liquid (water), and may be an immersion-type exposure device that exposes a substrate through a liquid, such as described in, 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. In addition, the exposure device is not limited to an exposure device for semiconductor manufacturing, and may be, for example, an exposure device for liquid crystal that transfers a liquid crystal display element pattern onto a rectangular glass plate.

[0243] In addition, all publications, international publications, U.S. patent application publications, and U.S. patent specifications relating to the exposure apparatus, etc. cited in the above embodiments shall be incorporated by reference into the description of this specification.

[0244] A semiconductor device is manufactured by undergoing a lithography step in which a photosensitive object is exposed using a patterned reticle (mask) and the exposed photosensitive object is developed, using an exposure device that constitutes a lithography system related to the above embodiment. In this case, a device of high integration density can be manufactured with a good yield.

[0245] In addition, the manufacturing process of a semiconductor device may include, in addition to the lithography step, a step for designing the function and performance of the device, a step for manufacturing a reticle (mask) based on the design step, a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, etc. Explanation of the symbols

[0246] 10… Slider 12… opposite 14… Vibration damping device 16… Base frame 18… Air bearings 20… drive system 20A… 1st driving device 20B… Second driving device 22a, 22b… operator 23a, 23b… Operator 24… Operating stage 25a, 25b… stator 26a, 26b… stator 28A, 28B… X-axis linear motor 29A, 29B… Y-axis linear motor 30… 1st position measurement system 32… Head section 33… Encoder System 35a ~ 35d… Laser Interferometer 37x… X head 37ya, 37yb… Y head 40… Measurement unit 48… Vibration damping device 50… Second position measurement system 52A, 52B… Head section 58X1, 58X2… XZ Head 58Y1, 58Y2… YZ Head 60… control device 100… measuring device 100a, 100b… measuring device 200… exposure device 300… C / D 330… Onjoba 1000… Lithography System MDS… Mark detector RG1… Grating RG2a, RG2b… Grating W… wafer WST… Wafer Stage

Claims

Claim 1 A measuring device described in the description of the present invention.

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