JP2005340315A - Alignment device, exposure apparatus, alignment method and exposure method, and device manufacturing method and (tool) reticle for calibration - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make an accurate alignment of an object. <P>SOLUTION: A tool reticle is loaded onto a pre-alignment stage 110, and positional information of a mark on the tool reticle is detected by a pre-alignment system 45. Then, the tool reticle is loaded onto a reticle stage RST via an exchange arm 120, and positional information of the reticle is detected by a reticle alignment system 22. From these detection results, a deviation is calculated between the pre-alignment detection system and the RA coordinate system. When actually making a pre-alignment of the reticle on the reticle pre-alignment stage 110, the calculated deviation is taken into consideration. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an alignment apparatus, an exposure apparatus, an alignment method and an exposure method, a device manufacturing method, and a calibration (tool) reticle, and more particularly, an alignment apparatus that aligns an object, and the alignment apparatus , An alignment method for aligning an object, an exposure method using the alignment method, a device manufacturing method using the exposure apparatus, and a stage movable in a two-dimensional plane A first coordinate system defined by detection results of a plurality of first detection systems that respectively detect position information in the two-dimensional plane of at least two marks on the pattern forming reticle, and is conveyed from the stage. Position information in the two-dimensional plane of each mark on the pattern forming reticle held by the holding device is detected. Calibration that is used to determine the information about the deviation between the second coordinate system defined by the detection results of the plurality of second detection systems for (tool) reticle.

  Conventionally, in a lithography process for manufacturing a semiconductor element, a liquid crystal display element, etc., a pattern (hereinafter also referred to as “reticle pattern”) formed on a mask or reticle (hereinafter also referred to as “reticle”) is projected. 2. Description of the Related Art An exposure apparatus that uses a wafer or a substrate such as a glass plate (hereinafter referred to as “wafer” as appropriate) coated with a resist or the like through an optical system is used. As such an exposure apparatus, a static exposure type exposure apparatus such as a so-called stepper and a scanning exposure type exposure apparatus such as a so-called scanning stepper are mainly used.

  In such an exposure apparatus, alignment between a reticle on a reticle stage and a wafer (reticle alignment) is performed by detecting position information of an alignment mark (reticle alignment mark) on the reticle by some detection system. Therefore, on the reticle stage, it is necessary to hold the reticle at an appropriate position so that the alignment mark falls within the detection field of the detection system. For this reason, so-called pre-alignment is performed in which the reticle is roughly aligned before the reticle is held on the reticle stage.

  In such pre-alignment, for example, the position of the reticle before being placed on the reticle stage is mechanically adjusted with a pin or the like, or by a detection system including an imaging device that images a reticle alignment mark formed on the reticle. The position information of the reticle is detected, and the position of the reticle is adjusted based on the detection result (see, for example, Patent Document 1). In the pre-alignment method described in Patent Document 1 or the like, the reticle is temporarily held on the pre-alignment stage before being loaded onto the reticle stage, and the position information of the reticle alignment mark formed on the reticle in this state is detected by a detection system. By detecting and adjusting the position of the pre-alignment stage based on the detection result, the position of the reticle before being loaded onto the reticle stage is adjusted.

However, in the pre-alignment performed by detecting the position information of the reticle described in Patent Document 1 or the like, it is desirable to calibrate the detection system in order to maintain the alignment accuracy. It is difficult to say that is sufficiently provided.
Japanese Patent Laid-Open No. 9-8103

  In view of the first aspect, the present invention made under the circumstances described above is an alignment apparatus for aligning an object (R1, R2, etc.), and is for detecting at least two positions within a predetermined two-dimensional plane. A stage (110) capable of holding an object in which two marks are respectively formed at predetermined positions and movable in the two-dimensional plane; and in the two-dimensional plane of each mark on the object held on the stage A first detection system (45) for detecting position information at; a transport device (120) for receiving and transporting the object held on the stage; and the object transported from the stage by the transport device; A holding device (RST) that receives and holds from the transport device; and detects position information of each mark in the two-dimensional plane in a state where the object is held by the holding device. A second detection system (22) for detecting position information of the object in the two-dimensional plane based on the detection result; and before and after attempting to convey the object from the stage to the holding device at least once Based on the detection result of the first detection system and the detection result of the second detection system, the first coordinate system defined by the detection result of the first detection system and the detection of the second detection system are obtained. And a calculation device (20) that calculates information related to a deviation from the second coordinate system defined by the result.

  According to this, the object is held by the calculation device and the first coordinate system defined by the detection result of the first detection system that detects the position information of the mark on the object when the object is held on the stage. Information relating to the shift of the second coordinate system defined by the detection result of the second detection system that detects the position information of the mark when held in the apparatus is calculated based on each detection result. Therefore, based on this calculation result, it is possible to accurately align the object when the object is transported in consideration of information regarding the deviation.

  According to a second aspect of the present invention, there is provided an alignment apparatus for aligning an object (R1, R2, etc.), wherein at least one mark for position detection in a predetermined two-dimensional plane is set at a predetermined position. A stage (110) capable of holding the formed object and movable in the two-dimensional plane; and detecting for detecting position information in the two-dimensional plane of the marks on the object held on the stage A system (45); a transport device (120) for receiving and transporting the object held on the stage; and a holder for receiving and holding the object transported from the stage by the transport device from the transport device An apparatus (RST); with the object held, the stage is moved a predetermined distance in at least one predetermined direction in the two-dimensional plane, and before and after the movement The position information of the mark is detected by the detection system, and based on the detection result, the rotational deviation between the detection coordinate system defined by the detection result of the detection system and the stage coordinate system defined by the movement of the stage A calculation device (20) for calculating information related to the stage; when transferring a new object from the stage to the holding device, based on the calculation result, the stage in the two-dimensional plane of the stage holding the object A second alignment device comprising: an adjustment device (20) for adjusting the position;

  According to this, the stage is moved by a predetermined distance in at least one predetermined direction in the two-dimensional plane by the calculation device, the position information of the mark on the object before and after the movement is detected by the detection system, and the detection result is Based on the actual movement of the stage, the information on the rotational deviation between the detection coordinate system defined by the detection result of the detection system and the stage coordinate system defined by the movement of the stage is calculated. The deviation can be obtained with high accuracy. Therefore, if the position of the stage is adjusted by the adjustment device based on the calculation result, the object can be aligned with high accuracy.

  From a third viewpoint, the present invention irradiates a mask (R2 or the like) with an energy beam, and transfers a pattern formed on the mask onto a photosensitive object (W) via a projection optical system (PL). An exposure apparatus (100), wherein at least one of the mask and the photosensitive object is the object, the first and second alignment apparatuses of the present invention; and the holding device of the alignment apparatus and the mask and the And a transfer device (20) for transferring a pattern formed on the mask onto the photosensitive object via the projection optical system in a state where at least one of the photosensitive object is held. In such a case, the object can be accurately aligned using the first and second alignment apparatuses of the present invention, so that highly accurate exposure can be realized.

  From a fourth viewpoint, the present invention is an alignment method for aligning an object (R1, R2, etc.), and includes at least two marks (L, R) for position detection in a predetermined two-dimensional plane. Holding the objects respectively formed at predetermined positions on a stage (110) movable in the two-dimensional plane; and the two-dimensional plane of each mark on the object held on the stage A second step of detecting position information in the interior by a first detection system (45); a third step of receiving the object from the stage, transporting it to a holding device (RST), delivering it, and holding the object on the holding device; A step of detecting position information of each mark in the two-dimensional plane in a state where the object is held by the holding device, and a position of the object in the two-dimensional plane based on the detection result A fourth step of detecting information by a second detection system (22); obtained before and after trying the first step, the second step, the third step, and the fourth step at least once. Based on the relationship between the detection result of the first detection system and the detection result of the second detection system, the first coordinate system defined by the detection result of the first detection system and the detection of the second detection system A fifth step of calculating information relating to a deviation from the second coordinate system defined by the result; when carrying a new object from the stage to the holding device, the object is based on the calculation result; And a sixth step of adjusting the position of the stage holding the two-dimensional plane in the two-dimensional plane.

  According to this, in the fifth step, the first coordinate system defined by the detection result of the first detection system that detects the position information of the mark when the object is held on the stage, and the object is held by the holding device. The information about the deviation of the second coordinate system defined by the detection result of the second detection system that detects the position information of the mark when being performed is calculated based on each detection result. Therefore, based on this calculation result, it is possible to accurately align the object when the object is transported in consideration of information regarding the deviation.

  According to a fifth aspect of the present invention, there is provided an alignment method for aligning an object (R1, R2), wherein at least one mark (L, R) for position detection in a predetermined two-dimensional plane is provided. A first step of holding an object formed at a predetermined position on a stage (110) movable in the two-dimensional plane; and in the two-dimensional plane of each mark on the object held on the stage A second step of detecting position information at the detection system (45); with the object held on the stage, the stage is moved a predetermined distance in at least one predetermined direction in the two-dimensional plane, and the movement Position information of the front and rear marks is detected by the detection system, and based on the detection result, the coordinate system defined by the detection result of the detection system and the movement of the stage are defined. A third step of calculating information on rotational deviation with respect to the coordinate system; when carrying a new object from the stage to a holding device (RST) capable of holding the object, based on the calculation result, And a fourth step of adjusting the position of the stage in the two-dimensional plane.

  According to this, in the third step, the stage is moved by a predetermined distance in at least one predetermined direction in the two-dimensional plane, the position information of the mark on the object before and after the movement is detected by the detection system, and the detection result Based on the detection result of the detection system, and information on the rotational deviation between the stage coordinate system defined by the movement of the stage is calculated. Can be obtained with high accuracy. Therefore, in the fourth step, the object can be accurately aligned by adjusting the position of the stage based on the calculation result.

  From the sixth aspect, the present invention irradiates a mask (R1, R2) with an energy beam, and transfers a pattern formed on the mask onto a photosensitive object (W) via a projection optical system (PL). A method of aligning at least one of the mask and the photosensitive object using the first and second alignment methods of the present invention; and at least one of the mask and the photosensitive object is positioned. And transferring the pattern formed on the mask after the alignment onto the photosensitive object via the projection optical system. In such a case, since the alignment of at least one of the mask and the photosensitive object is performed using the first and second alignment methods of the present invention, highly accurate exposure can be realized.

  According to a seventh aspect of the present invention, there is provided a device manufacturing method including a lithography process, wherein in the lithography process, exposure is performed using the exposure method of the present invention. In such a case, since the exposure is performed using the exposure method of the present invention, the productivity of highly integrated devices can be improved.

  According to an eighth aspect of the present invention, positional information in the two-dimensional plane of at least two marks on the pattern forming reticles (R1, R2) held on a stage movable in the two-dimensional plane. And a first coordinate system (45 / reticle PRE2) defined by detection results of a plurality of first detection systems that respectively detect the first detection system and the pattern forming reticle carried by the stage and held by a holding device. It is used to obtain information relating to a deviation from the second coordinate system (22 / VRA) defined by detection results of a plurality of second detection systems that detect position information of each mark in the two-dimensional plane. A calibration reticle (RT), which has at least two mark areas (L, R), and each of the mark areas includes a calibration reticle (ST). Are arranged within the detection field of view of the plurality of first detection systems, and when the calibration reticle is held on the holding device, the plurality of second detection systems. The first mark having the same shape as the mark formed on the pattern forming reticle is formed on the calibration reticle so as to be placed within the detection field of view. (L0) and at least three calibration marks (L1 to L4) for two-dimensional position detection arranged with the first mark as a reference.

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

  FIG. 1 schematically shows a perspective view of an exposure apparatus 100 according to an embodiment capable of suitably performing the alignment method and the exposure method of the present invention. In FIG. 1, among the components of the exposure apparatus 100, the exposure apparatus main body and the reticle transport system for transporting the reticle to the exposure apparatus main body are shown centering on the reticle transport system.

  In this exposure apparatus 100, the exposure apparatus main body is configured with the projection optical system PL as the center, and performs exposure by a step-and-scan method. In FIG. 1, the direction of the optical axis AX of the projection optical system PL is the Z-axis direction, the scanning direction in which the reticle and wafer are synchronously moved in a plane orthogonal to the Z-axis direction is the Y-axis direction, and Y The non-scanning direction orthogonal to the axis is the X-axis direction.

  The exposure apparatus 100 includes, as an exposure apparatus main body, an illumination system (not shown), a reticle stage RST that holds a reticle (reticle RE2 in FIG. 1), and a projection optical system that projects illumination light through the reticle onto a wafer W as a photosensitive object. PL, wafer stage WST for holding wafer W, reticle alignment detection system 22, and main control device 20 (not shown in FIG. 1, refer to FIG. 2) as a control system thereof.

  The illumination system (not shown) has a slit-like illumination area that is elongated in the X-axis direction on the reticle RE2 on which a circuit pattern or the like is drawn by illumination light that is an ultraviolet line, far ultraviolet light, or vacuum ultraviolet light. Illuminate with illuminance.

  The reticle stage RST can be slightly driven in the XY plane (in the rotation direction θz around the Z axis) by a reticle stage drive system 25 (not shown in FIG. 1, see FIG. 2) including a linear motor, a voice coil motor, and the like. Is also possible to move at a set scanning speed in the Y-axis direction.

  The position of reticle stage RST in the XY plane is always measured with a laser interferometer (hereinafter referred to as “reticle interferometer”) 16 (not shown in FIG. 1, see FIG. 2) with a resolution of, for example, about 0.5 to 1 nm. Has been. Here, actually, as the reticle interferometer 16, a reticle X interferometer having the X axis as the measurement axis and a reticle Y interferometer having the Y axis as the measurement axis are provided. At least one of them is provided. For example, the reticle Y interferometer is a two-axis interferometer having two measurement axes. Based on the measurement value of the reticle Y interferometer, in addition to the Y position of the reticle stage RST, the θz direction (around the Z axis) The amount of rotation (the amount of yawing) in the direction of rotation) can also be measured. Here, the reticle Y interferometer is a two-axis interferometer.

  Position information (including the yawing amount) of reticle stage RST from reticle interferometer 16 is supplied to main controller 20 (see FIG. 2). Main controller 20 drives and controls reticle stage RST via reticle stage drive system 25 (see FIG. 2) based on the position information of reticle stage RST, and a reticle (FIG. 1) held on reticle stage RST. Then, the position of the reticle RE2) is controlled.

  The projection optical system PL is disposed below the reticle stage RST in FIG. 1 (on the −Z side). The projection optical system PL is composed of a plurality of lens elements (not shown) having a common optical axis AX in the Z-axis direction, and both the object plane (reticle RE2) side and the image plane (wafer W) side are telecentric. This is a reduction refractive optical system having a circular projection field (so-called bilateral telecentric). For this reason, when the illumination area of reticle RE2 is illuminated by illumination light from an illumination system (not shown), the imaging light beam from the portion illuminated by pulsed ultraviolet light in the circuit pattern of reticle RE2 is projected into the projection optical system. The light is incident on the PL, and a reduced image (partial inverted image) of the circuit pattern is formed in a slit-like shape at the center of the circular field on the image plane side of the projection optical system PL for each pulse irradiation. As a result, the projected image of the circuit pattern is reduced and transferred to the resist layer on the wafer W arranged on the imaging plane of the projection optical system PL.

  Wafer stage WST is disposed on a base (not shown) below projection optical system PL in FIG. 1 (on the −Z side). Wafer stage WST is driven by wafer stage drive system 24 (not shown in FIG. 1, see FIG. 2), X, Y, Z, θz (rotation direction around Z axis), θx (rotation direction around X axis), and This is a single stage that can be driven in the direction of 6 degrees of freedom of θy (rotation direction about the Y axis). Wafer W is held on wafer stage WST by, for example, vacuum suction or the like via a wafer holder (not shown).

  The position of wafer stage WST is always measured by a laser interferometer (hereinafter referred to as “wafer interferometer”) 18 (not shown in FIG. 1, see FIG. 2) with a resolution of about 0.5 to 1 nm, for example. Yes. In practice, a wafer X interferometer having a length measuring axis in the X axis direction and a wafer Y interferometer having a length measuring axis in the Y axis direction are provided. In FIG. A total of 18 is shown. These interferometers are composed of multi-axis interferometers having a plurality of measurement axes, and in addition to the X and Y positions of wafer stage WST, rotation (yawing (θz rotation that is rotation around the Z axis)), pitching (X axis) Rotation around (θx rotation) and rolling (θy rotation around Y axis)) can also be measured. Main controller 20 drives and controls wafer stage WST via wafer stage drive system 24 (see FIG. 2) based on the position information of wafer stage WST, and determines the position of wafer W held on wafer stage WST. Control.

  A reference mark plate FM is fixed in the vicinity of wafer W on wafer stage WST. The surface of the reference mark plate FM is set to substantially the same height as the surface of the wafer W, and various marks such as at least a pair of reticle alignment reference marks are formed on the surface.

  Although not shown, in the vicinity of the projection optical system PL, the off-axis alignment system is separated by a predetermined distance from the optical axis of the projection optical system PL (almost coincident with the projection center of the reticle pattern image). Placed in position. This alignment system is used for measuring the position information of the reference mark on the reference mark plate FM on the wafer stage WST or the alignment mark on the wafer W.

The reticle alignment detection system 22 is a VRA (Visual Reticle Alignment) type detection system that performs image processing on image data of an alignment mark imaged by an image sensor such as a CCD camera and measures the mark position, and is the same as the exposure light. An epi-illumination system (not shown) for irradiating the alignment mark with illumination light of a wavelength, imaging devices 22L and 22R for capturing an image of the alignment mark, and a detection device 22D (not shown in FIG. 1) 2). Illumination light from an epi-illumination system (not shown) is guided onto a reticle (reticle RE2 in FIG. 1) by a mirror (not shown), and a pair of reticle alignment marks on the reticle and a reference mark plate FM on wafer stage WST. Illuminate the upper reticle alignment reference mark. The reticle alignment mark illuminated with the illumination light and the reference mark on the reference mark plate FM are imaged by the imaging devices 22L and 22R of the reticle alignment detection system 22. The imaging data of the imaging devices 22L and 22R is sent to the detection device 22D. The detection device 22D detects position information of each mark in the imaging field of the imaging devices 22L and 22R based on the imaging data. For example, when detecting the position of the pair of reticle alignment marks, the detection device 22D detects the position of one reticle alignment mark detected from the imaging result of the imaging device 22L and the other detected from the imaging result of the imaging device 22R. The reticle RE2 on the two-dimensional coordinate system (hereinafter referred to as “RA coordinate system”) defined by the imaging devices 22L and 22R, that is, defined by the reticle alignment detection system 22, from the detection position of the reticle alignment mark. The center position (dX _RS , dY _RS ) and the rotation component θ _RS are calculated, and the calculation result is supplied to the main controller 20. In the reticle alignment detection system 22, the midpoint of the line segment connecting the center of the imaging field of the imaging device 22L and the center of the imaging field of the imaging device 22R coincides with the optical axis of the projection optical system PL. When the imaging devices 22L and 22R are arranged and the center of the imaging field of the imaging devices 22L and 22R and the reticle alignment mark coincide with each other, the center position (dX _RS , dY _RS ) of the reticle RE2 is ( 0, 0) and the rotation component θ _RS is also set to 0.

  Although not shown, an oblique incidence type focus detection system (focus detection system) for detecting the position in the Z-axis direction (the direction of the optical axis AX) in the exposure area on the surface of the wafer W and in the vicinity thereof. One multi-point focus position detection system is provided. During the exposure, main controller 20 determines the wafer stage so that the best imaging plane of projection optical system PL and the surface of wafer W coincide with each other within the depth of focus based on the detection result of the multipoint focus position detection system. Control WST. The detailed configuration of this multipoint focus position detection system is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 6-283403, and thus detailed description thereof is omitted.

  Next, the configuration of the reticle transport system for transporting the reticle to the exposure apparatus main body will be described. The reticle transport system includes a storage shelf 150, a transport robot 51, a pre-alignment stage 110, a pre-alignment system 45, and an exchange arm 120.

  The storage shelf 150 is a shelf that can store a plurality of reticles used in the exposure apparatus 100. The reticles RE1 and RE2 shown in FIG. 1 are the reticles stored in the storage shelf 150. In this embodiment, the later-described tool reticle used for calibration of the pre-alignment system 45 is also stored in the storage shelf 150. It shall be.

  The transfer robot 51 is a horizontal articulated robot (scalar robot), which can freely move the posture of the arm tip in the horizontal direction and can be driven in the vertical direction. The tip of the arm of the transfer robot 51 can suck the reticle by vacuum suction or electrostatic suction. The posture of the transfer robot 51 is detected by an encoder that detects the rotation of a motor that drives each joint of the robot and a position sensor that detects the position of the arm (the encoder and the position sensor 11 in FIG. 2). Information detected by the encoder and the position sensor 11 is sent to the main control device 20, and the transfer robot 51 performs reticle control on the tip of the arm under posture control by the main control device 20 (see FIG. 2) based on the information. The reticle is taken out from the storage shelf 150 and transported to a pre-alignment stage 110 described later, or the reticle held on the pre-alignment stage 110 is returned to the storage shelf 150.

  The pre-alignment stage 110 is disposed on the −Y side of the reticle stage RST on a surface plate on which the reticle stage RST is placed. The pre-alignment stage 110 is a stage for performing pre-alignment on the reticle before being held on the reticle stage RST. On the pre-alignment stage 110, the reticle carried in by the carrying robot 51 as described above is placed. The pre-alignment stage 110 sucks and holds the reticle placed in this way by vacuum suction or electrostatic suction. The pre-alignment stage 110 is a table that can move in the XY plane (including the θz direction), and is controlled by the main controller 20 via a pre-alignment stage drive system 31 (see FIG. 2) such as a linear motor. The position is controlled.

  The pre-alignment system 45 includes imaging devices 45L and 45R such as a CCD camera disposed above (+ Z side) the pre-alignment stage 110. The imaging devices 45L and 45R are arranged so that the vicinity of the reticle alignment mark formed on the reticle (reticle RE1 in FIG. 1) held on the pre-alignment stage 110 can be imaged. The imaging results obtained by the imaging devices 45L and 45R are sent to the main control device 20, and the main control device 20 detects the position information of the reticle alignment mark based on the imaging results. The detection result is used for reticle alignment before the reticle is placed on the reticle stage RST, so-called pre-alignment (reticle pre-alignment).

  The exchange arm 120 is provided on the drive shaft 104 of the vertical movement / rotation mechanism, the arm drive unit 102 fixed to the lower end of the drive shaft 104, and one side and the other side of the arm drive unit 102, respectively. Each pair of arms 106 and 108 is provided.

  As shown in the plan view of FIG. 3, with the rotation of the drive shaft 104, the arm drive unit 102 rotates about the drive shaft 104, and the arms 106 and 108 turn in the XY plane. ing. Further, as the drive shaft 102 is driven in the vertical direction (Z-axis direction, the direction perpendicular to the paper surface in FIG. 3), the arm drive unit 102 and the arms 106 and 108 are movable in the Z-axis direction. The arms 106 and 108 are opened and closed by the arm drive unit 102.

  FIGS. 1 and 3 show a state in which reticle RE1 is held on pre-alignment stage 110 and reticle RE2 is held on reticle stage RST. From this state, when reticle exchange is performed by the exchange arm 120, the reticle RE1 is conveyed to the reticle stage RST, the reticle RE2 is conveyed to the pre-alignment stage 110, and both reticles are exchanged.

  In each of reticles RE1 and RE2, a pattern surface to be exposed is formed on the −Z side, and reticle alignment marks are formed on both sides of the pattern surface in the X-axis direction. On the pattern surface side (−Z side) of the reticles RE1 and RE2, a pellicle is provided as a transparent protective film for protecting the pattern surface and the reticle alignment mark. The pre-alignment stage 110 and the reticle stage RST respectively hold the reticles RE1 and RE2 by suction through the pellicle, and the outer peripheral portions of the reticles RE1 and RE2 are in a state of being separated from both the stages 110 and RST. As shown in FIG. 3, the exchange arm 120 closes the arms 106 and 108 at an appropriate timing while lowering the arms 106 and 108 with the arms 106 and 108 opened from the state shown in FIG. In addition, by setting the arms 106 and 108 between the stages 110 and RST and the outer peripheral portions of the reticles RE1 and RE2, the reticles RE1 and RE2 are supported from below. The rotational position of the exchange arm 120 is detected by a rotational position sensor 46 (see FIG. 2). The main controller 20 controls the drive shaft 104 and the arm drive unit 102 of the exchange arm 120 based on the rotation position of the exchange arm 120 from the rotation position sensor 46.

  As shown in FIG. 2, the control system in the exposure apparatus 100 of the present embodiment is configured with a main controller 20 including a workstation (or a microcomputer) as the center, and the main controller 20 is not shown. A CPU, a main memory, and a storage device are provided. The main control device 20 performs various controls as described above and executes overall control of the entire device by the CPU executing a program read from the storage device into the main memory. That is, the main control device 20 executes a program corresponding to the control algorithm on the CPU, thereby detecting information related to the transfer robot 51 that transfers the reticle and information related to the posture related to the transfer robot 51 sent from the position sensor 11. Based on this, the transport robot 51 is driven and controlled, and the prealignment stage 110 is driven and controlled via the prealignment stage drive system 31 based on the detection result of the prealignment system 45. Then, main controller 20 controls drive shaft 104 and arm drive unit 102 based on the rotation of exchange arm 120 detected from rotational position sensor 46.

  As described above, in exposure apparatus 100, the reticle is transported onto reticle stage RST by the reticle transport system. More specifically, the reticle stored in the storage shelf 150 is transported to the pre-alignment stage 110 by the transport robot 51, and reticle pre-alignment based on the detection result of the pre-alignment system 45 is performed on the pre-alignment stage 110. After being broken, it is held on the reticle stage RST by the exchange arm 120. Main controller 20 performs reticle alignment on the reticle held on reticle stage RST using reticle alignment system 22 and performs scanning exposure using the result of the reticle alignment.

  By the way, in order to perform reticle pre-alignment accurately, it is necessary to calibrate the pre-alignment system 45 and the pre-alignment stage 110 that perform pre-alignment in advance. Therefore, regarding the reticle pre-alignment calibration operation in the exposure apparatus 100, the plan view of the tool reticle shown in FIGS. 4A to 4C, FIGS. 5A to 5D, and FIG. ) To FIG. 6C and the like, and a flowchart showing the algorithm of the main controller 20 shown in FIGS. 7 to 11 will be described with reference to other drawings as appropriate.

  In the pre-alignment calibration operation of the present embodiment, a tool reticle RT as shown in FIG. FIG. 4A is a plan view of the tool reticle RT viewed from the pattern surface side (−Z side). As shown in FIG. 4A, the tool reticle RT is configured around a substantially rectangular glass substrate, and its structure is substantially the same as that of the reticles RE1 and RE2, and is on the reticles RE1 and RE2. A pair of marks L and R corresponding to the pair of reticle alignment marks is formed. RC indicates the center of the tool reticle RT.

FIG. 4B shows an enlarged view of the mark L, and FIG. 4C shows an enlarged view of the mark R. As shown in FIG. 4B, the mark L includes a search mark L0 formed at the center and calibration marks L1 to L4 formed at the four corners. The search mark L0 includes a box mark and a line pattern formed along the four sides thereof, and is the same mark as the reticle alignment mark formed on the reticles RE1 and RE2. Calibration marks L1 to L4 are box marks. That is, the search mark L0 and the calibration marks L1 to L4 are two-dimensional position detection marks that can detect the two-dimensional positions of the marks. The calibration marks L1 to L4 are set to be larger than the search mark L0. The design center position of the search mark L0 on the tool reticle RT is (X _L0 , Y _LO ), and the design center positions of the calibration marks L1 to L4 are (X _L1 , Y _L1 ), (X _L2 , _YL2 ), ( _XL3 , _YL3 ), and ( _XL4 , _YL4 ). The calibration marks L1 to L4 are formed so that the average of the center positions of the calibration marks L1 to L4 matches the center position of the search mark L0.

As shown in FIG. 4C, the mark R is the same mark as the mark L, and includes a search mark R0 and calibration marks R1 to R4. Here, the design center position of the search mark R0 on the tool reticle is (X _R0 , Y _RO ), and the design center position of each calibration mark R1 to R4 is (X _R1 , Y _R1 ), ( X _R2 , Y _R2 ), (X _R3 , Y _R3 ), and (X _R4 , Y _R4 ).

  The marks R and L are different from the reticle alignment marks of the reticles RE1 and RE2 in that they include calibration marks.

  In the present embodiment, it is assumed that the tool reticle RT is stored in the storage shelf 150. The design center positions of the marks L and R are stored in a storage device (not shown) of the main controller 20.

<Camera calibration>
One of the reticle pre-alignment calibration operations of the present embodiment is camera calibration, that is, calibration processing of the cameras (imaging devices 45L and 45R) of the pre-alignment system 45. FIG. 5A shows a tool reticle defined by the in-camera coordinate system (X _CLS , Y _CLS ) and (X _CRS , Y _CRS ) defined by the imaging results of the imaging devices 45L and 45R and the tool reticle RT. The relationship with the coordinate system (X _P , Y _P ) is shown. As shown in FIG. 5 (A), the tool reticle coordinate system is a coordinate system having an origin O _P the center RC of the tool reticle RT. The in-camera coordinate systems (X _CLS , Y _CLS ) and (X _CRS , Y _CRS ) are coordinate systems defined by the respective imaging fields. The deviation between the tool reticle coordinate system and the coordinate systems in both cameras is the origin position deviation (X _L , Y _L ), (X _R , Y _R ), rotational deviation θ _L , θ _R , and imaging magnification (MX _L , MY _L ), (MX _R , MY _R ). In the calibration process of this embodiment, the tool reticle RT is actually loaded on the pre-alignment stage 110, and the calibration marks L1 to L of the marks L and R formed on the tool reticle RT held on the pre-alignment stage 110 are used. By detecting the position information of L4, R1 to R4, information relating to the deviation between the two coordinate systems is obtained.

  Note that when pre-aligning an actual reticle, this tool reticle coordinate system serves as a reference coordinate system for pre-alignment. Therefore, this coordinate system is also referred to as a pre-alignment coordinate system. This pre-alignment coordinate system is a coordinate system different from the pre-alignment stage coordinate system defined by the movement of the pre-alignment stage 110 described later.

  Hereinafter, steps 701 to 717 in FIG. 7 show the calibration processing of the imaging devices 45L and 45R. First, it is assumed that no reticle is held on the pre-alignment stage 110 and the reticle stage RST.

  First, as shown in FIG. 7, in step 701, the tool reticle RT stored in the storage shelf 150 is taken out by the transfer robot 51 and loaded onto the pre-alignment stage 110.

  In the next step 703, it is determined whether or not the search marks L0 and R0 of the tool reticle RT are in the vicinity of the visual field center of the imaging devices 45L and 45R, that is, within a range based on the visual field center (for example, within ± 8 pixels). To do. If this determination is affirmed, the process proceeds to step 705, and if not, the process proceeds to step 707. It is assumed that the imaging data captured by the imaging devices 45L and 45R is always transmitted to the main control device 20, and the image is displayed on the display device of the main control device 20. The operator looks at this image and confirms whether or not the search mark L0 of the mark L and the search mark R0 of the mark R are within the center of the image (for example, within ± 8 pixels from the center of the image). The confirmation result is input to the main controller 20 through the input device. Main controller 20 makes the above determination based on the input confirmation result. However, the image of the search marks L0 and R0 is processed by performing image processing such as template matching between the imaging result and the pattern corresponding to the search marks L0 and R0 in the main controller 20 without confirmation by the operator. The position information may be detected to make the above determination automatically.

  In step 705, it is determined whether or not four calibration marks (C marks in FIG. 7) L1 to L4 and R1 to R4 are included in the imaging field of view of the imaging devices 45L and 45R, respectively. If this determination is affirmed, the process proceeds to step 709, and if not, the process proceeds to step 707. Here again, the operator looks at the images captured by the imaging devices 45L and 45R displayed on the display device, the calibration marks L1 to L4 are in the imaging device 45L, and the calibration marks R1 to R4 are captured. It is confirmed whether or not it is in the device 45R, and the confirmation result is input to the main controller 20 through the input device. Main controller 20 makes the above determination based on the input confirmation result. In this case as well, without the confirmation by the operator, image processing such as template matching is performed in the main controller 20 to detect the position information of the calibration marks L1 to L4 and R1 to R4, and the above determination is made. May be automatically performed.

  In Step 707, the four calibration marks L1 to L4 and R1 to R4 are included in the imaging device so that the search marks L0 and R0 are within a predetermined range based on the center of the imaging field of the imaging devices 45L and 45R. The position of the pre-alignment stage 110 is finely adjusted so as to enter the imaging fields of 45L and 45R, respectively. The adjustment of the stage position of the pre-alignment stage 110 can be manually performed by an operator's operation via an input device. That is, main controller 20 finely adjusts the position of pre-alignment stage 110 via pre-alignment stage drive system 31 according to an instruction input from the input device. After step 707 is completed, the process returns to step 703.

  As described above, when the main control device 20 automatically makes the determinations in step 703 and step 705 by image processing, in step 707, the main control device 20 performs pre-processing based on the image processing result. Fine adjustment of the position of the alignment stage 110 may be automatically performed via the pre-alignment stage drive system 31.

  Thereafter, the position of the pre-alignment stage 110 is finely adjusted in step 707 until the determination in step 703 and step 705 is affirmed. Finally, the search marks L0 and R0 are displayed in the imaging field of view of the imaging devices 45L and 45R. The calibration marks L1 to L4 and R1 to R4 are located near the center so that they are within the imaging field of view of the imaging devices 45L and 45R. If all the above determinations are not affirmed even if the position of the pre-alignment stage 110 is finely adjusted several times, the tool reticle RT on the pre-alignment stage 110 is replaced by the transfer arm 51. Also good.

  Hereinafter, what is executed in steps 709 to 717 is a calibration process for the imaging devices 45L and 45R of the pre-alignment system 45. In step 709, images taken by the imaging devices 45L and 45R are acquired. That is, the imaging data sent from the imaging devices 45L and 45R is stored in a main memory (not shown).

  In the next step 711, design coordinate values of the calibration marks L1 to L4 and R1 to R4 and the search marks L0 and R0 are set on the tool reticle RT. That is, the design coordinate values of the calibration marks L1 to L4 and R1 to R4 and the design coordinate values of the search marks L0 and R0 are read from a storage device (not shown) into the main memory.

In the next step 713, based on the captured imaging data, a coordinate system (in-camera coordinate system (X _CLS , Y _CLS ) shown in FIG. X _CRS , Y _CRS )), the center positions of the calibration marks L1 to L4 and R1 to R4 are detected. This detection is performed on each calibration mark L1 to L4 and R1 to R4 obtained from the imaging data, based on the feature that the pattern of the four sides is symmetric with respect to the center. This is performed by detecting a position where the mirror symmetry of the luminance distribution of the portions corresponding to the action marks L1 to L4 and R1 to R4 is maximum. Here, the detected calibration mark L1 to L4, the center position of the R1 to R4, respectively _{CL1 (X CL1, Y CL1)} ~CL4 (X CL4, Y CL4), CR1 (X CR1, Y CR1) ~CR4 and (X _CR4, Y _CR4).

  In the next step 715, based on the coordinate values of the calibration marks L1 to L4 and R1 to R4 obtained in step 713, the camera coordinate system of the imaging devices 45L and 45R of the search marks L0 and R0 is calculated using the following equation. The positions CL0 and CR0 are calculated.

なお、上記式（１）における、（Ｘ_CLi，Ｙ_CLi）（Ｘ_CRi，Ｙ_CRi）は、検出されたキャリブレーションマークＬ１〜Ｌ４，Ｒ１〜Ｒ４の中心位置ＣＬ１（Ｘ_CL1，Ｙ_CL1）〜ＣＬ４（Ｘ_CL4，Ｙ_CL4）、ＣＲ１（Ｘ_CR1，Ｙ_CR1）〜ＣＲ４（Ｘ_CR4，Ｙ_CR4）を示している。なお、以降では、説明を簡略化するため、キャリブレーションマークＬ１〜Ｌ４，Ｒ１〜Ｒ４の中心位置の座標に対し、適宜、マークの識別するための番号を示す添え字としてｉ（ｉ＝１〜４）を用いることとする。なお、算出した位置ＣＬ０、ＣＲ０の位置座標は、記憶装置に記憶される。

In the above formula (1), (X _CLi , Y _CLi ) (X _CRi , Y _CRi ) are the center positions CL1 (X _CL1 , Y _CL1 ) to the detected calibration marks L1 to L4, R1 to R4. _{CL4 (X CL4, Y CL4)} , shows the _{CR1 (X CR1, Y CR1)} ~CR4 (X CR4, Y CR4). In the following, for simplification of explanation, i (i = 1 to 1) is used as a subscript indicating a number for identifying the mark as appropriate with respect to the coordinates of the center positions of the calibration marks L1 to L4 and R1 to R4. 4) is used. The calculated position coordinates of the positions CL0 and CR0 are stored in the storage device.

Here, the relationship between the in-camera coordinate systems ((X _CLS , Y _CLS ), (X _CRS , Y _CRS )) of the imaging devices 45L and 45R and the tool reticle coordinate system (X _P , Y _P ) will be described. FIG. 5A shows the in-camera coordinate systems ((X _CLS , Y _CLS ), (X _CRS , Y _CRS )) of the imaging devices 45L and 45R and the tool reticle coordinate system (X _P , Y _P ). The relationship is shown. The position offsets at the origins of the tool reticle coordinate system and the in-camera coordinate system are L (X _L , Y _L ) and R (X _R , Y _R ), respectively, and the imaging magnification in each axial direction of the imaging devices 45L and 45R is M. Calibration on each in-camera coordinate system, where _XL , M _YL , M _XR , and M _YR are the rotation components of the imaging device 45L and 45R and the tool reticle coordinate system are θ _L and θ _R The relationship between the measured values of the marks L1 to L4 and R1 to R4 and the positions of the calibration marks L1 to L4 and R1 to R4 on the tool reticle coordinate system is as follows.

ここで、上記（２）における（Ｘ_Li，Ｙ_Li）、（Ｘ_Ri，Ｙ_Ri）は、各キャリブレーションマークＬ１〜Ｌ４の設計上の中心位置（Ｘ_L1，Ｙ_L1）、（Ｘ_L2，Ｙ_L2）、（Ｘ_L3，Ｙ_L3）、（Ｘ_L4，Ｙ_L4）、（Ｘ_R1，Ｙ_R1）、（Ｘ_R2，Ｙ_R2）、（Ｘ_R3，Ｙ_R3）、（Ｘ_R4，Ｙ_R4）を示している。

Here, (X _Li , Y _Li ) and (X _Ri , Y _Ri ) in the above (2) are design center positions (X _L1 , Y _L1 ), (X _L2 , _{Y L2), (X L3,} Y L3), (X L4, Y L4), (X R1, Y R1), (X R2, Y R2), (X R3, Y R3), (X R4, Y R4 ).

Here, when the design value of the imaging magnification of the imaging devices 45L and 45R is M, the imaging magnifications M _XL , M _YL , M _XR , and M _YR can be converted as follows.

上記式（３）を用いれば、上記式（２）を、次式に変換することができる。

If the said Formula (3) is used, the said Formula (2) can be converted into following Formula.

さらに、上記式（４）を展開し、１次の微少量だけとると、次式が得られる。

Further, when the above equation (4) is developed and only a first-order minute amount is taken, the following equation is obtained.

ここで、ｉ＝１、２、３、４として、上記式（５）を展開すると、次式のようになる。

Here, when i = 1, 2, 3, 4 and the above equation (5) is expanded, the following equation is obtained.

上記式（６）は、次式のようにまとめることができる。

The above equation (6) can be summarized as the following equation.

ここで、Ｓ_L、Ｓ_Rは、次式のようになる。

Here, S _L and S _R are expressed by the following equations.

Ｐ_L ^T等、上付きのＴがついている行列は、その行列の転置行列である。次のステップ７１７では、最小二乗法を用いて上記式（８）を解き、（Ｘ_L，Ｙ_L）、（Ｘ_R，Ｙ_R）、（ｄＭ_XL，ｄＭ_YL）、（ｄＭ_XR，ｄＭ_YR）、θ_L，θ_Rの値を求め、カメラ位置（（Ｘ_L，Ｙ_L）、（Ｘ_R，Ｙ_R））、撮像倍率（（Ｍ_XL，Ｍ_YL）、（Ｍ_XR，Ｍ_YR））、回転θ_L，θ_Rを算出する。そして、求められたカメラ位置、倍率、回転は、装置パラメータとして主制御装置２０の不図示の記憶装置に記憶される。ステップ７１７終了後は、図８のステップ８０１に進む。

P _L ^T, etc., is a matrix that is with a superscript T is a transposed matrix of the matrix. In the next step 717, the above equation (8) is solved using the least square method, and (X _L , Y _L ), (X _R , Y _R ), (dM _XL , dM _YL ), (dM _XR , dM _YR). ), Θ _L , θ _R are obtained, camera position ((X _L , Y _L ), (X _R , Y _R )), imaging magnification ((M _XL , M _YL ), (M _XR , M _YR )) ), Rotations θ _L and θ _R are calculated. The obtained camera position, magnification, and rotation are stored in a storage device (not shown) of the main controller 20 as device parameters. After step 717, the process proceeds to step 801 in FIG.

That is, when the position of the mark is detected from the images captured from the imaging devices 45L and 45R, the position of the mark in the camera coordinate system is (X _CLS , Y _CLS ) (X _CLS , Y _CLS ), respectively. The position of the mark in the pre-alignment coordinate system is calculated using the following equation.

ここで、各マークのプリアライメント座標系の位置座標を（Ｘ_LS，Ｙ_LS）、（Ｘ_RS，Ｙ_RS）としている。

Here, the position coordinates of each mark in the pre-alignment coordinate system are (X _LS , Y _LS ) and (X _RS , Y _RS ).

《Pre-alignment stage axial calibration》
In steps 701 to 717 described above, the imaging devices 45L and 45R of the pre-alignment system 45 are calibrated and the deviation between the in-camera coordinate system and the pre-alignment coordinate system is obtained. This is determined by the holding state of the tool reticle RT and is different from the pre-alignment stage coordinate system defined by the actual movement of the pre-alignment stage 110. In pre-alignment, since the pre-alignment stage 110 is moved to adjust the position of the reticle, it is necessary to obtain the relationship between the pre-alignment coordinate system and the pre-alignment stage coordinate system. Therefore, in steps 801 to 823 in FIG. 8 below, a rotational deviation between both coordinate systems is detected.

FIG. 5B shows the relationship between the pre-alignment coordinate system (X _P , Y _P ) and the pre-alignment stage coordinate system (X _S , Y _S ). As shown in FIG. 5 (B), and X _P axis of the pre-alignment coordinate system, the angle between the X _S axis of the prealignment stage coordinate system and alpha, and the Y _P axis of the ply alignment coordinate system, pre-alignment _Let β be the angle formed with the Y _S axis of the stage coordinate system. The pre-alignment stage coordinate system is determined by the direction of each drive axis of the pre-alignment stage 110 (the drive direction of each motor of the pre-alignment stage drive system 31), and the directions of the drive axes are not necessarily perpendicular to each other. Not necessarily. For this reason, the deviation angle in the X-axis direction is designated as α, and the deviation angle in the Y-axis direction is designated as β. In steps 801 to 823 in FIG. 8, the deviation angles α and β are obtained.

  First, in step 801, the pre-alignment stage 110 is moved by a predetermined distance (for example, +1 mm) in the X-axis direction (see FIG. 5B). Then, in step 803, images captured by the imaging devices 45L and 45R are acquired. In step 805, the center positions of the calibration marks L1 to L4 and R1 to R4 are detected from the acquired images. , The positions L0a and R0a of the search marks L0 and R0 are calculated from the positions of the calibration marks L1 to L4 and R1 to R4 detected in step 805. Since the positions L0a and R0a need to be position coordinates on the pre-alignment coordinate system, they are assumed to be position coordinates converted from the in-camera coordinate system using the above equation (9).

FIG. 5C shows the position L0 (X _L0 , Y _LO ) of the search mark L0 before the movement on the design (that is, on the pre-alignment coordinate system) and the calculated search mark L0 after the movement. The relationship with the position L0a is shown. As shown in FIG. 5 (C), the line segment connecting the position L0 and the position L0a is will have an angle of rotation α with respect to the coordinate axes X _P prealignment coordinate system. Therefore, in step 809, the rotation angle α between the pre-alignment stage coordinate system defined by the movement of the pre-alignment stage 110 and the pre-alignment coordinate system defined by the imaging results of the imaging devices 45L and 45R is calculated using the following equation. Ask for.

ここで、（Ｘ_L0，Ｙ_L0）、（Ｘ_R0，Ｙ_R0）は、この移動前のプリアライメント座標系上のサーチマークＬ０，Ｒ０の中心位置であり、（Ｘ_L0a，Ｙ_L0a）、（Ｘ_R0a，Ｙ_R0a）は、移動後のプリアライメント座標系上のサーチマークＬ０，Ｒ０の中心位置である。なお、求められた回転角αは、不図示の記憶装置に記憶される。

Here, (X _L0 , Y _L0 ), (X _R0 , Y _R0 ) are the center positions of the search marks L 0, R 0 on the pre-alignment coordinate system before the movement, and (X _L0a , Y _L0a ), ( X _R0a , Y _R0a ) are the center positions of the search marks L0, R0 on the pre-alignment coordinate system after movement. The obtained rotation angle α is stored in a storage device (not shown).

  In the next step 811, the pre-alignment stage 110 is moved a predetermined distance (for example, −1 mm) in the X-axis direction, and the position is returned to the original position. In step 813, the pre-alignment stage 110 is further moved by a predetermined distance (for example, 1 mm) in the Y-axis direction. In step 815, images captured by the imaging devices 45L and 45R are acquired in this state, and in step 817. The positions of the calibration marks L1 to L4 and R1 to R4 are detected from the acquired image. In step 819, the positions of the calibration marks L1 to L4 and R1 to R4 detected in step 817 are used to search the search mark L0. , R0, the center position L0b of the pre-alignment coordinate system is calculated. In step 821, the rotation angle β between the pre-alignment stage coordinate system defined by the movement of the pre-alignment stage 110 and the pre-alignment coordinate system is obtained using the following equation.

ここで、（Ｘ_L0，Ｙ_L0）、（Ｘ_R0，Ｙ_R0）は、この移動前のプリアライメント座標系上のサーチマークＬ０，Ｒ０の中心位置であり、（Ｘ_L0a，Ｙ_L0a）、（Ｘ_R0a，Ｙ_R0a）は、移動後のプリアライメント座標系上のサーチマークＬ０，Ｒ０の中心位置である。なお、求められた回転角βは不図示の記憶装置に記憶される。

Here, (X _L0 , Y _L0 ), (X _R0 , Y _R0 ) are the center positions of the search marks L 0, R 0 on the pre-alignment coordinate system before the movement, and (X _L0a , Y _L0a ), ( X _R0a , Y _R0a ) are the center positions of the search marks L0, R0 on the pre-alignment coordinate system after movement. The obtained rotation angle β is stored in a storage device (not shown).

  In the next step 823, the rotation angle Φ between the pre-alignment stage coordinate system and the pre-alignment coordinate system is obtained using the following equation.

求められた回転角Φは、不図示の記憶装置に記憶され、ステップ８２３終了後、図９のステップ９０１に進む。

The obtained rotation angle Φ is stored in a storage device (not shown), and after step 823, the process proceeds to step 901 in FIG.

  If the orthogonality of the coordinate axes of the pre-alignment stage 110 is sufficiently ensured, Φ = α = β, so that the processing of Step 811 to Step 821 or the processing of Step 801 to Step 811 is not performed. Alternatively, β may be used as the rotational deviation amount of both coordinate systems as it is. Alternatively, step 823 may not be performed, and α and β may be stored in the storage device as they are as rotational deviation amounts of both coordinate systems. Further, the amount of movement of the pre-alignment stage 110 in the X-axis direction and the amount of movement in the Y-axis direction do not have to be the same ± 1 mm, and it is only necessary to calculate according to the amount of movement. Further, step 811 is not necessarily performed.

《Pre-alignment stage rotation axis calibration》
In steps 901 to 923 in FIG. 9, the rotation axis of the pre-alignment stage 110 is calibrated. As described above, the pre-alignment stage 110 is rotatable in the θz direction. In this embodiment, the pre-alignment is performed by adjusting the rotation amount of the stage in the θz direction. The rotation center of the pre-alignment stage 110 is not always coincident. Therefore, in steps 901 to 923, the rotation center position of the pre-alignment stage 110 on the pre-alignment coordinate system is calculated. Here, as shown in FIG. 6A, the pre-alignment stage 110 holding the tool reticle RT is rotated by a predetermined angle, for example, ± 1 mrad, and the centers of the search marks L0 and R0 on the tool reticle RT at that time Based on the change in position, the rotational center position T of the pre-alignment stage 110 is detected. In the following description, the counterclockwise (counterclockwise) rotation is positive and the clockwise (counterclockwise) rotation is negative.

First, in step 901 of FIG. 9, the pre-alignment stage 110 is rotated by a predetermined angle (for example, −1 mrad), and in step 903, images captured by the imaging devices 45L and 45R in that state are acquired. In step 905, the center positions of the calibration marks L1 to L4 and R1 to R4 in the pre-alignment coordinate system defined by the imaging results of the imaging devices 45L and 45R are detected. In step 907, the center positions are obtained in step 905. From the center positions of the calibration marks L1 to L4 and R1 to R4, the center positions TL ₂ (X _TL2 , Y _TL2 ) and TR ₂ (X _TR2 , Y _TR2 ) of the search marks L0 and R0 on the pre-alignment coordinate system. Is calculated (see FIG. 6B).

In step 909, the pre-alignment stage 110 is rotated by a predetermined angle (for example, +1 mrad) to return its position to the original position. In the next step 911, images captured by the imaging devices 45L and 45R in that state are acquired. In step 913, the center positions of the calibration marks L1 to L4 and R1 to R4 in the pre-alignment coordinate system defined by the imaging results of the imaging devices 45L and 45R are detected. In step 915, the center positions are obtained in step 913. From the center positions of the calibration marks L1 to L4 and R1 to R4, the center positions TL ₀ (X _TL0 , Y _TL0 ), TR ₀ (X _TR0 , Y _TR0 ) of the search marks L0 and R0 on the pre-alignment coordinate system. Is calculated (see FIG. 6B).

In the next step 917, the pre-alignment stage 110 is further rotated by a predetermined angle (for example, +1 mrad), and in step 919, images captured by the imaging devices 45L and 45R in that state are acquired. In step 921, the center positions of the calibration marks L1 to L4 and R1 to R4 in the camera coordinate system of the imaging devices 45L and 45R are detected, and in step 923, the calibration marks L1 to L1 obtained in step 921 are detected. The center positions TL ₁ (X _TL1 , Y _TL1 ) and TR ₁ (X _TR1 , Y _TR1 ) of the search marks L0, R0 on the pre-alignment coordinate system are calculated from the center positions of L4, R1 to R4 (FIG. 6 ( B)).

  Here, the positional relationship of the search mark R0 before and after the rotation in step 917 is expressed by the following equation.

（Ｘ_T，Ｙ_T）は、プリアライメントステージ１１０の回転中心位置Ｔの位置座標である。上記式（１３）を、次式のように変換することができる。

(X _T , Y _T ) are position coordinates of the rotation center position T of the pre-alignment stage 110. The above equation (13) can be converted into the following equation.

同様に、上記ステップ９１７の回転前後におけるサーチマークＬ０の位置関係は次式に示されるようになる。

Similarly, the positional relationship of the search mark L0 before and after the rotation of step 917 is expressed by the following equation.

また、上記ステップ９０９の回転前後におけるサーチマークＲ０の位置関係は次式に示されるようになる。

Further, the positional relationship of the search mark R0 before and after the rotation of step 909 is expressed by the following equation.

また、上記ステップ９０９の回転前後におけるサーチマークＬ０の位置関係は次式に示されるようになる。

Further, the positional relationship of the search mark L0 before and after the rotation of step 909 is expressed by the following equation.

上記式（１４）〜式（１７）をまとめると、次式のようになる。

The above formulas (14) to (17) are summarized as follows.

ここで、上記式（１８）は、次式のようにまとめられる。

Here, the above equation (18) is summarized as the following equation.

そこで、次のステップ９２５では、最小二乗法によって次式を用いて、プリアライメントステージ１１０の回転中心位置Ｔの位置座標（Ｘ_T，Ｙ_T）を算出する。

Therefore, in the next step 925, the position coordinates (X _T , Y _T ) of the rotation center position T of the pre-alignment stage 110 are calculated using the following equation by the least square method.

ステップ９２５終了後は、図１０のステップ１００１に進む。

After step 925 is completed, the process proceeds to step 1001 in FIG.

  In Steps 901 to 925, the pre-alignment stage 110 is rotated clockwise by a predetermined angle and then counterclockwise twice, by a predetermined angle. However, the present invention is not limited to this. Of course, it is good, and you may make it rotate to either one 3 times. Moreover, each rotation angle does not need to be the same, and the calculation according to the rotation angle should just be made.

Further, before the pre-alignment stage 110 is rotated in step 901, the center positions TL ₀ (X _TL0 , Y _TL0 ) and TR ₀ (X _TR0 , Y _TR0 ) of the search marks L0 and R0 on the pre-alignment coordinate system are measured. Steps 911 to 915 may be omitted. In this embodiment, the number of measurement points is three for each camera. However, the number of rotations of the pre-alignment stage 110 may be increased so that the number of measurement points is four or more.

≪Calibration of deviation between pre-alignment coordinate system and RA coordinate system≫
In Step 1001 to Step 1011 of FIG. 10, calibration of deviation between the pre-alignment coordinate system and the RA coordinate system is performed. As described above, the pre-alignment coordinate system is a coordinate system determined by the position of the tool reticle RT. Even if the tool reticle RT is loaded onto the reticle stage RST by the exchange arm 120, the tool reticle at that time is loaded. The coordinate system does not necessarily match the RA coordinate system. Therefore, here, information relating to the deviation between the pre-alignment coordinate system and the RA coordinate system is detected by measuring the position of the mark on the tool reticle RT after being loaded on the reticle stage RST.

  In step 1001 of FIG. 10, the tool reticle RT is loaded on the reticle stage RST. In step 1003, the reticle alignment system 22 is instructed to detect the position of the tool reticle RT held on the reticle stage RST. After execution of step 1003, the process proceeds to step 1005 and waits until the detected reticle position is sent from the detection device 22D (FIG. 2).

The detection device 22D of the reticle alignment system 22 calculates the center positions of the search marks L0 and R0 in the RA coordinate system based on the imaging result of the tool reticle RT imaged by the imaging devices 22L and 22R. Then, based on the calculated center positions of the search marks L0 and R0, the center position (dX _RS , dY _RS ) of the tool reticle RT and the rotation component θ _RS are calculated and supplied to the main controller 20. . After acquiring the reticle position of the tool reticle RT, the process proceeds to Step 1007.

Here, the relationship between the pre-alignment coordinate system and the RA coordinate system will be described. FIG. 6C shows the relationship between both coordinate systems. FIG. 6C shows a pre-alignment coordinate system (X _P , Y _P ) and an RA coordinate system (X _R , Y _R ), and the positional deviation of the origin of both coordinate systems is (dX, dY). ) And the rotational deviation of both coordinate systems is shown as dθ.

If the relationship between the two coordinate systems is as shown in FIG. 6C, the position coordinates (x _P , y _P ) of a point on the pre-alignment coordinate system are converted to the position coordinates (x _The conversion formula for converting to _{R 1} , y _R ) is expressed by the following formula.

ここで、ｄθ＜＜１であるとすると、上記式（２１）を、次式に変換することができる。

Here, when dθ << 1, the above equation (21) can be converted into the following equation.

さらに、１次の微小量をとると、上記式（２２）を、次式に変換することができる。

Furthermore, when the first minute amount is taken, the above equation (22) can be converted into the following equation.

ここで、未知数が（ｄＸ，ｄＹ，ｄθ）であることを考慮して、上記式（２３）を変形すると、次式が得られる。

Here, taking into account that the unknown is (dX, dY, dθ), the above equation (23) is transformed to obtain the following equation.

なお、レチクルアライメント検出系２２の検出装置２２Ｄからは、レチクル中心位置ずれ量（ｄＸ_RS，ｄＹ_RS）とレチクル回転θ_RSが出力されるので、工具レチクルＲＴの中心からサーチマークＬ０，Ｒ０までの距離をＬＸ_RSとすると、ＲＡカメラ座標系での工具レチクルＲＴ上のサーチマークＬ０，Ｒ０の座標値は、次式に示される（ｘ_RL，ｙ_RL）、（ｘ_RR，ｙ_RR）となる。

The detection device 22D of the reticle alignment detection system 22 outputs the reticle center position shift amount (dX _RS , dY _RS ) and the reticle rotation θ _RS, and therefore, from the center of the tool reticle RT to the search marks L0, R0. When the distance is LX _RS , the coordinate values of the search marks L0 and R0 on the tool reticle RT in the RA camera coordinate system are (x _RL , y _RL ) and (x _RR , y _RR ) shown in the following equations. .

また、プリアライメント座標系での工具レチクルＲＴ上のサーチマークＬ０，Ｒ０の中心位置を、それぞれ（ｘ_PL、ｙ_PL）、（ｘ_PR，ｙ_PR）とすると、プリアライメント座標系と、ＲＡ座標系でのサーチマークＬ０，Ｒ０の位置の関係を、次式のように表すことができる。

If the center positions of the search marks L0 and R0 on the tool reticle RT in the pre-alignment coordinate system are (x _PL , y _PL ) and (x _PR , y _PR ), respectively, the pre-alignment coordinate system and the RA coordinate The relationship between the positions of the search marks L0 and R0 in the system can be expressed as follows:

さらに、上記式（２６）を、次式のようにまとめることができる。

Furthermore, the above equation (26) can be summarized as the following equation.

そこで、ステップ１００７において、最小二乗法を用いて次式を解けば、図６（Ｃ）に示される両座標系のずれ（ｄＸ，ｄＹ，ｄθ）を求めることができる。

Therefore, in step 1007, by solving the following equation using the least square method, the deviation (dX, dY, dθ) between the two coordinate systems shown in FIG. 6C can be obtained.

ステップ１００７終了後は、ステップ１００９に進む。ステップ１００９では、交換アーム１２０を用いて工具レチクルＲＴをレチクルステージＲＳＴからアンロードし、プリアライメントステージ１１０に搬送する。ステップ１０１１では、搬送ロボット５１により、工具レチクルＲＴをプリアライメントステージ１１０からアンロードし、収納棚１５０に収納する。

After step 1007, the process proceeds to step 1009. In step 1009, the tool reticle RT is unloaded from the reticle stage RST using the exchange arm 120 and conveyed to the pre-alignment stage 110. In step 1011, the tool reticle RT is unloaded from the pre-alignment stage 110 by the transfer robot 51 and stored in the storage shelf 150.

  In this embodiment, the deviation between the RA coordinate system and the pre-alignment coordinate system is detected by executing Step 1001 to Step 1009 once. However, the present invention is not limited to this, and Step 1001 to Step 1009 are executed a plurality of times. Thus, the deviation between the two coordinate systems may be obtained using the following equation as a basic equation.

ここで、上記式（２９）のマトリクスの各要素における添え字Ｎは、その要素の値が、工具レチクルＲＴのレチクルステージＲＳＴ上へのＮ回目のロード時に検出されたデータであることを示している。上記式（２９）を、次式のようにまとめることができる。

Here, the subscript N in each element of the matrix of the above formula (29) indicates that the value of the element is data detected at the time of the Nth loading on the reticle stage RST of the tool reticle RT. Yes. The above equation (29) can be summarized as the following equation.

そして、この場合も、同様に次式を用いて、最小二乗法により、両座標系のずれ（ｄＸ，ｄＹ，ｄθ）を求めることができる。

In this case as well, the deviation (dX, dY, dθ) between the two coordinate systems can be obtained by the least square method using the following equation.

このようにすれば、交換アーム１２０によるレチクル交換の再現性を考慮して両座標系のずれを検出することができるようになり、最小二乗法により導きだされる解の信頼性を向上させることができる。

By doing so, it becomes possible to detect the deviation of both coordinate systems in consideration of the reproducibility of reticle exchange by the exchange arm 120, and to improve the reliability of the solution derived by the least square method. Can do.

  Thus, the reticle pre-alignment calibration operation using the tool reticle RT is completed. By the calibration operation described above, values as shown in Tables 1 to 3 below are stored in the storage device of the main controller 20. Main controller 20 stores the data shown in Table 1 as reticle pre-alignment camera constants (camera magnification, camera rotation, camera position), and the data shown in Table 2 as reticle pre-alignment stage constants (rotation center position). , Tool reticle rotation amount with respect to the pre-alignment stage), and data shown in Table 3 is stored in the storage device as a constant between the RA coordinate system and the pre-alignment coordinate system.

  Next, an exposure operation in the exposure apparatus 100 will be described. In the following description, it is assumed that the reticle is not loaded in the exposure apparatus 100 yet. FIG. 11 is a flowchart showing the pre-alignment operation of the reticle.

As shown in FIG. 11, first, in step 301, a reticle (reticle RE <b> 2) is loaded onto the pre-alignment stage 110. In step 303, the pre-alignment stage 110 is moved to the origin position. In step 305, images captured by the imaging devices 45L and 45R are acquired in this state. In step 307, the reticle is obtained based on the images. The positions CLS (X _CLS , Y _CLS ) and CRS (X _CRS , Y _CRS ) of the reticle alignment mark on RE2 on the in-camera coordinate system are detected.

In the next step 309, the reticle alignment mark on the pre-alignment coordinate system is calculated from the position CLS (X _CLS , Y _CLS ) and CRS (X _CRS , Y _CRS ) of the reticle alignment mark in the in-camera coordinate system using the following equation. Positions LS (X _LS , Y _LS ) and RS (X _RS , Y _RS ) are calculated.

さらに、ステップ３１１において、プリアライメント座標系におけるレチクルアライメントマークの位置ＬＳ（Ｘ_LS，Ｙ_LS）、ＲＳ（Ｘ_RS，Ｙ_RS）に基づいて、次式を用いて、プリアライメント座標系上のレチクルＲＥ２の中心位置の座標Ｃ（Ｘ_C，Ｙ_C）と、レチクル回転ずれθ_Cを算出する。図１２には、プリアライメント座標系上のレチクルＲＥ２の中心位置Ｃ（Ｘ_C，Ｙ_C）の一例が示されている。

Further, in step 311, based on the reticle alignment mark positions LS (X _LS , Y _LS ) and RS (X _RS , Y _RS ) in the pre-alignment coordinate system, the reticle on the pre-alignment coordinate system is calculated using the following equation. The coordinates C (X _C , Y _C ) of the center position of RE2 and the reticle rotational deviation θ _C are calculated. FIG. 12 shows an example of the center position C (X _C , Y _C ) of the reticle RE2 on the pre-alignment coordinate system.

次のステップ３１３では、プリアライメントステージ１１０を−θ_C＋ｄθ分だけ回転補正する。プリアライメントステージ１１０の回転中心Ｔ（Ｘ_T，Ｙ_T）とレチクルＲＥ２の中心位置Ｃとがずれているため、この回転により、レチクルＲＥ２の中心位置が移動する。プリアライメント座標系上の移動後のレチクル中心位置の位置座標は、次式に示される、Ｃ’（Ｘ_C’，Ｙ_C’）となる（図１２参照）。

In the next step 313, the rotation of the pre-alignment stage 110 is corrected by −θ _C + dθ. Since the rotation center T (X _T , Y _T ) of the pre-alignment stage 110 and the center position C of the reticle RE2 are deviated, this rotation moves the center position of the reticle RE2. The position coordinate of the reticle center position after movement on the pre-alignment coordinate system is C ′ (X _C ′, Y _C ′) represented by the following equation (see FIG. 12).

そして、次のステップ３１５で、次式を計算して、プリアライメント座標系上の位置補正量ｄｘ（Ｘ_M，Ｙ_M）を算出する。図１２に示されるように、プリアライメント座標系とＲＡ座標系とは（ｄＸ，ｄＹ）だけずれているため、次式では、そのオフセット分が考慮されている。

In the next step 315, the following equation is calculated to calculate a position correction amount dx (X _M , Y _M ) on the pre-alignment coordinate system. As shown in FIG. 12, since the pre-alignment coordinate system and the RA coordinate system are shifted by (dX, dY), the offset is taken into consideration in the following equation.

そして、この位置補正量Ｄを、次式を用いて、プリアライメントステージ座標系での移動量Ｄ’（Ｘ’_M，Ｙ’_M）に変換する。

Then, the position correction amount D is converted into a movement amount D ′ (X ′ _M , Y ′ _M ) in the pre-alignment stage coordinate system using the following equation.

次のステップ３１７では、位置補正量Ｄ’だけ、プリアライメントステージ１１０を移動して、レチクルＲＥ２に対するプリアライメント動作を終了する。

In the next step 317, the pre-alignment stage 110 is moved by the position correction amount D ′, and the pre-alignment operation for the reticle RE2 is completed.

  Then, the exchange arm 120 loads the reticle RE2 onto the reticle stage RST. Then, wafer stage WST is moved below projection optical system PL, and a pair of reticle alignment marks formed on reticle RE2 on reticle stage RST and a pair of first reference marks on the reference mark plate corresponding thereto are provided. The positional relationship is detected using the reticle alignment system 22, and thereby the relative position of the projection center of the reticle pattern with respect to the pair of first reference marks is detected.

  Further, the baseline measurement of the center of the field of view of the off-axis alignment detection system (not shown) and the projection center of the reticle pattern is also performed.

  After such measurement is performed, the wafer W is loaded on the wafer stage WST, and the shot area of the previous layer is already formed on the wafer W, and the overlay exposure is performed on the shot area of the layer. Prior to the start of exposure, wafer alignment of an EGA (Enhanced Global Alignment) system using an alignment detection system is performed on the wafer W, and array coordinates (a pair of the above-described pairs) of shot areas on the wafer W are performed. Of the second reference mark whose positional relationship with the first reference mark is known).

  Then, based on the measured baseline and the result of wafer alignment, the operation of moving wafer stage WST to the scanning start position (acceleration start position) for exposure of each shot area on wafer W, and reticle RE2 A step-and-scan exposure operation is performed in which a scanning exposure operation in which (reticle stage RST) and wafer W (wafer stage WST) are synchronously scanned in the Y-axis direction is repeated. As a result, the pattern of the reticle R is sequentially transferred to each of a plurality of shot areas on the wafer W.

  Then, when the exposure of wafer W is completed, wafer stage WST is moved to the wafer exchange position and the wafer is exchanged. When the wafer exchange is completed, EGA measurement and exposure operations are performed in the same manner as described above.

  During this series of operations, the reticle RE1 used for the next exposure is transported and held on the reticle prestage 110. Then, the pre-alignment shown in steps 301 to 317 is also performed on the reticle RE1.

  Then, when the necessity for exchanging the reticle arises, the exchanging operation of the exchanging arm 120 causes the reticle RE1 waiting on the pre-alignment stage 110 to be exchanged with the reticle RE2 on the reticle stage RST. Then, during exposure using the reticle RE1 after the replacement, the reticle RE2 on the pre-alignment stage 110 is stored in the storage shelf 150 by the transfer arm 51, and a new reticle to be used next is pre-aligned. The pre-alignment operation in steps 301 to 317 is performed on the reticle loaded on the stage 110.

  As is clear from the above description, in the present embodiment, the main control device 20 corresponds to the calculation device and adjustment device of the exposure apparatus of the present invention. That is, steps 701 to 717 (FIG. 7), steps 801 to 823 (FIG. 8), steps 901 to 925 (FIG. 9), and steps 1001 to 1011 (FIG. 10) performed by the CPU of the main controller 20. The function of the calculation device is realized by the processing of step 301, and the function of the adjustment device is realized by the processing of step 301 to step 317 (FIG. 11).

  As described above in detail, according to the present embodiment, detection of the pre-alignment system 45 (first detection system) that detects the position information of the mark on the reticle when the reticle is held on the pre-alignment stage 110. A pre-alignment coordinate system (first coordinate system) defined by the result and a reticle alignment system 22 (second detection system) that detects position information of a mark on the reticle when the reticle is held on the reticle stage RST. Information about the shift of the RA coordinate system (second coordinate system) defined by the detection result is calculated based on each detection result. Therefore, based on this calculation result, it is possible to accurately align the reticle in consideration of the information regarding the deviation when transporting the reticle (positioning reproducibility when the reticle is loaded on the reticle stage). For example, it can be realized at about 285 μm or less).

  That is, according to the present embodiment, when a new reticle is transferred from the pre-alignment stage 110 to the reticle stage RST, the main controller 20 controls the reticle based on the information on the deviation between the two coordinate systems. The position in the XY plane of the pre-alignment stage 110 to be held can be adjusted with high accuracy. In other words, using the information regarding this deviation, when trying to align the reticle before conveyance so that the position of the reticle after conveyance becomes a desired position, the reticle can be aligned with the deviation canceled. It can be done.

  In this embodiment, the information regarding the deviation between the pre-alignment coordinate system and the RA coordinate system includes the positional deviation amount (dX, dY) and the rotational deviation amount (dθ) of the origin between the pre-alignment coordinate system and the RA coordinate system. Contains.

  In this embodiment, the main controller 20 moves the pre-alignment stage 110 holding the reticle by +1 mm in the X-axis direction and the Y-axis direction, and position information of at least one mark on the reticle before and after the movement. Is detected by the pre-alignment system 45, and information on the rotational deviation between the pre-alignment coordinate system and the pre-alignment stage coordinate system defined by the movement of the pre-alignment stage 110 is calculated based on the detection result, and the main controller No. 20 considers information about rotational deviation between the pre-alignment coordinate system and the pre-alignment stage coordinate system when adjusting the position of the pre-alignment stage 110 in the XY plane. In this way, since the shift between the two coordinate systems can be accurately obtained based on the actual movement of the pre-alignment stage 110, the reticle can be adjusted by adjusting the position of the pre-alignment stage 110 based on the calculation result. Can be accurately aligned. Note that the amount of movement of the pre-alignment stage 110 is not limited to 1 mm, and may be within the range of the imaging field of view of the imaging devices 45L and 45R.

  In this embodiment, the pre-alignment stage 110 holding the reticle is sequentially moved in the X-axis direction and the Y-axis direction, and the position information of the reticle alignment mark before and after the movement is detected by the pre-alignment system 45. Based on the detection result, the average rotational deviation between the pre-alignment coordinate system and the pre-alignment stage coordinate system calculated for the movement in each coordinate axis direction can be detected with high accuracy as information on the rotational deviation. In this case, the movement direction of the pre-alignment stage 110 is not limited to the X-axis direction and the Y-axis direction, and any direction in the XY plane can be selected.

  In this case, the position information of the mark on the reticle before and after the movement of the pre-alignment stage 110 in the X-axis direction and the Y-axis direction is detected by the pre-alignment system 45, and based on the detection result, the pre-alignment stage coordinate system Therefore, when adjusting the position of the pre-alignment stage 110 in the XY plane, the orthogonality of the coordinate axes of the pre-alignment stage coordinate system can be taken into consideration.

  As described above, in the present embodiment, the pre-alignment stage 110 is moved in the X-axis direction and the Y-axis direction, respectively, and the information regarding the rotational deviation between the pre-alignment coordinate system and the pre-alignment stage coordinate system is calculated. In the case where the orthogonality of the coordinate axes of the pre-alignment stage coordinate system is guaranteed, information on the rotational deviation of both coordinate systems may be calculated by only moving in either the X-axis direction or the Y-axis direction.

  In the present embodiment, the pre-alignment stage 110 that holds the tool reticle RT reticle is rotated around the predetermined reference point T by a predetermined angle (for example, ± 1 mrad) in the XY plane, and the reticle alignment marks before and after the rotation are rotated. The position information of L and R is detected by the pre-alignment system 45, the position coordinate of the reference point T on the pre-alignment coordinate system is calculated based on the detection result, and the position of the pre-alignment stage 110 in the XY plane is adjusted. In doing so, the deviation between the center position of the reticle calculated from the position information of each mark and the reference point T is taken into consideration. In this way, the reticle can be accurately aligned regardless of the positional deviation between the center of the reticle and the rotation reference point T of the pre-alignment stage 110. In this case, the rotation amount of the pre-alignment stage 110 is not limited to ± 1 mrad, and may be within the range of the imaging field of view of the imaging devices 45L and 45R.

  In the present embodiment, the pre-alignment system 45 includes a plurality of imaging devices 45L and 45R that respectively image the alignment marks on the reticle, and based on the imaging results of the imaging devices 45L and 45R, This is a detection system for detecting position information. Then, main controller 20 holds tool reticle RT including reticle alignment marks L, R including four XY position detection calibration marks L1-L4, R1-R4 on pre-alignment stage 110. The position information of the calibration marks L1 to L4 and R1 to R4 is simultaneously detected by the pre-alignment system 45, and the detection results and the design formation positions of the calibration marks L1 to L4 and R1 to R4 Based on the above, the calibration information of the imaging devices 45L and 45R is calculated. Then, main controller 20 considers the calibration information of imaging devices 45L and 45R when adjusting the position of pre-alignment stage 110 in the XY plane (specifically, using the above equation (9)). , Convert the position information of each mark). As described above, the tool reticle RT is arranged so that the four calibration marks (L1 to L4 or R1 to R4) detected at the same time can be detected by the prealignment system 45, and the calibration marks 45 are simultaneously detected by the prealignment system 45. By using the position information of the four marks, it is possible to accurately calculate the calibration information of the imaging devices of those detection systems without moving the pre-alignment stage 110.

  Note that the reticle alignment marks L and R have four calibration marks L1 to L4 and R1 to R4, but are not limited thereto. The reticle alignment mark only needs to be provided with at least three calibration marks that are not on the same straight line so as to be within the imaging field of view of each camera.

  At this time, the calibration information of the imaging devices 45L and 45R includes the imaging magnification of the imaging devices 45L and 45R and the origin position of the camera coordinate system and the pre-alignment coordinate system defined by the imaging results of the imaging devices 45L and 45R. The shift amount and the rotation shift amount can be included, and the shift between both coordinate systems in the XY plane can be completely grasped.

  Further, in this embodiment, after performing Step 801 to Step 823 in FIG. 8, Step 901 to Step 925 in FIG. 9 are performed, but these may be reversed.

  Further, in the present embodiment, the swing type exchange arm 120 is used as the transfer device, but the present invention is not limited to this, and a translational slider type may be used. In the present embodiment, the transport system transports a rectangular reticle. However, the present invention is not limited to this, and the reticle may be circular.

  Further, according to the present embodiment, a pattern formed on the reticle is passed through the projection optical system PL in a state where the reticle transported using the reticle transport system as described above is held on the reticle stage RST. Since it is transferred onto the wafer, highly accurate exposure can be realized. However, in the present embodiment, the present invention is applied only to the alignment of the reticle, but the present invention can of course be applied to the alignment of the wafer or the alignment of both the reticle and the wafer.

  In the above embodiment, the case where the present invention is applied to a scanning stepper of a single wafer stage type has been described. However, the present invention is not limited to this, and a double processing that realizes high throughput by parallel processing on two wafer stages. The present invention can also be applied to a wafer stage type scanning stepper. The present invention can also be suitably applied to a step-and-repeat type exposure apparatus that transfers a mask pattern to a substrate while the mask and wafer (substrate) are stationary. The present invention can also be applied to a proximity exposure apparatus that transfers a mask pattern onto a substrate by bringing the mask and the substrate into close contact with each other without using a projection optical system. Further, it can be a reduction projection exposure apparatus of a step and stitch system, and the present invention can be applied to a mirror projection aligner and a photo repeater.

The present invention is not limited to the exposure light source. As a light source of an illumination system (not shown) that emits the exposure light IL, far ultraviolet light such as KrF excimer laser light source (oscillation wavelength 248 nm), ArF excimer laser light source (oscillation wavelength 193 nm), or F ₂ laser light source (oscillation wavelength 157 nm). Those emitting light such as vacuum ultraviolet light can be used. It is also possible to use an ultra-high pressure mercury lamp that generates ultraviolet emission lines (g-line, i-line, etc.). Further, it may be used other vacuum ultraviolet light source such as Ar ₂ laser light source (output wavelength 126 nm). Further, for example, not only laser light sources output from the above light sources as vacuum ultraviolet light, but also infrared or visible single wavelength laser light oscillated from DFB (Distributed FeedBack) semiconductor lasers or fiber lasers. A light source that irradiates, as illumination light, harmonics that are amplified with a fiber amplifier doped with erbium (Er) (or both erbium and ytterbium (Yb)) and converted into ultraviolet light using a nonlinear optical crystal. It may be used. In addition, the present invention may be applied to an exposure apparatus that uses EUV light, X-rays, or charged particle beams such as electron beams and ion beams as exposure beams. Furthermore, the present invention may be applied to an immersion type exposure apparatus disclosed in, for example, International Publication WO99 / 49504 and the like, in which a liquid is filled between the projection optical system PL and the wafer W.

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

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

  The present invention is not limited to an exposure apparatus for manufacturing a semiconductor, but is used for manufacturing a display including a liquid crystal display element. An exposure apparatus for transferring a device pattern onto a glass plate and a device used for manufacturing a thin film magnetic head. The present invention can also be applied to an exposure apparatus that transfers a pattern onto a ceramic wafer, and an exposure apparatus that is used for manufacturing an imaging device (CCD or the like), micromachine, organic EL, DNA chip, and the like.

  An illumination optical system and projection optical system composed of a plurality of lenses are incorporated into the exposure apparatus body for optical adjustment, and a reticle stage and wafer stage made up of a number of mechanical parts are attached to the exposure apparatus body to provide wiring and piping. , And further performing general adjustment (electrical adjustment, operation check, etc.), the exposure apparatus of the above embodiment can be manufactured. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  Furthermore, the alignment method of the present invention can be suitably applied to an apparatus such as an inspection apparatus or a processing apparatus other than the exposure apparatus as long as it is an apparatus that requires positioning accuracy of an object after conveyance.

<Device manufacturing method>
Next, an embodiment of a device manufacturing method using the exposure apparatus 100 described above in a lithography process will be described.

  FIG. 13 shows a flowchart of a manufacturing example of a device (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). As shown in FIG. 13, first, in step 201 (design step), device function / performance design (for example, circuit design of a semiconductor device) is performed, and pattern design for realizing the function is performed. Subsequently, in step 202 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

  Next, in step 204 (wafer processing step), using the mask and wafer prepared in steps 201 to 203, an actual circuit or the like is formed on the wafer by lithography or the like as will be described later. Next, in step 205 (device assembly step), device assembly is performed using the wafer processed in step 204. Step 205 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary.

  Finally, in step 206 (inspection step), inspections such as an operation confirmation test and durability test of the device created in step 205 are performed. After these steps, the device is completed and shipped.

  FIG. 14 shows a detailed flow example of step 204 in the semiconductor device. In FIG. 14, in step 211 (oxidation step), the surface of the wafer is oxidized. In step 212 (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode formation step), an electrode is formed on the wafer by vapor deposition. In step 214 (ion implantation step), ions are implanted into the wafer. Each of the above-described steps 211 to 214 constitutes a pre-processing process at each stage of wafer processing, and is selected and executed according to a necessary process at each stage.

  At each stage of the wafer process, when the above pre-process is completed, the post-process is executed as follows. In this post-processing process, first, in step 215 (resist formation step), a photosensitive agent is applied to the wafer. Subsequently, in step 216 (exposure step), the circuit pattern of the mask is transferred to the wafer using the exposure apparatus 100 of the above embodiment. Next, in step 217 (development step), the exposed wafer is developed, and in step 218 (etching step), the exposed members other than the portion where the resist remains are removed by etching. In step 219 (resist removal step), the resist that has become unnecessary after the etching is removed.

  By repeatedly performing these pre-processing steps and post-processing steps, multiple circuit patterns are formed on the wafer.

  If the device manufacturing method of this embodiment described above is used, the exposure apparatus 100 of the above embodiment is used in the exposure step (step 216), so that highly accurate exposure can be realized. As a result, it becomes possible to produce a device with a higher degree of integration.

  The alignment apparatus and method of the present invention are suitable for aligning an object. The exposure apparatus and method of the present invention are suitable for performing an exposure processing operation including mask exchange or wafer exchange. The device manufacturing method of the present invention is suitable for the production of microdevices, and the calibration reticle of the present invention is suitable for calibration of an apparatus for aligning an object.

1 is a perspective view showing an exposure apparatus according to an embodiment of the present invention. 2 is a block diagram showing a configuration of a control system of exposure apparatus 100. FIG. It is a top view which shows a reticle exchange mechanism. 4A is a plan view illustrating an example of a tool reticle, FIG. 4B is a diagram illustrating an example of an alignment mark L, and FIG. 4C illustrates an example of an alignment mark R. FIG. FIG. 5A is a diagram showing the relationship between the pre-alignment coordinate system and the camera coordinate system, and FIG. 5B is a diagram showing the relationship between the pre-alignment coordinate system and the pre-alignment stage coordinate system. FIG. 5C is a diagram showing how the mark L moves when moved in the X-axis direction, and FIG. 5D shows the movement of the mark R when moved in the Y-axis direction. It is a figure which shows a mode. 6A is a diagram showing the rotation center of the pre-alignment stage, FIG. 6B is a diagram showing the rotation of the mark accompanying the rotation of the pre-alignment stage, and FIG. 6C is the diagram showing the pre-alignment stage. It is a figure which shows the shift | offset | difference of an alignment coordinate system and RA coordinate system. It is a flowchart (the 1) which shows the calibration operation | movement of the reticle conveyance system of the exposure apparatus 100 which concerns on one Embodiment of this invention. It is a flowchart (the 2) which shows the calibration operation | movement of the reticle conveyance system of the exposure apparatus 100 which concerns on one Embodiment of this invention. It is a flowchart (the 3) which shows the calibration operation | movement of the reticle conveyance system of the exposure apparatus 100 which concerns on one Embodiment of this invention. It is a flowchart (the 4) which shows the calibration operation | movement of the reticle conveyance system of the exposure apparatus 100 which concerns on one Embodiment of this invention. It is a flowchart which shows the operation | movement of the reticle pre-alignment of the exposure apparatus 100 which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the center position of the reticle in a pre-alignment coordinate system. It is a flowchart for demonstrating embodiment of the device manufacturing method which concerns on this invention. It is a flowchart which shows the detail of step 204 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Main-control apparatus (calculation apparatus, adjustment apparatus), 22 ... Reticle alignment system (2nd detection system), 45 ... Pre-alignment system (1st detection system), 45L, 45R ... Imaging apparatus, 100 ... Exposure apparatus, 110 ... pre-alignment stage (stage), 120 ... exchange arm (conveying device), R ... reticle, RST ... reticle stage (holding device), RT ... tool reticle, W ... wafer.

Claims (18)

An alignment device for aligning an object,
A stage capable of holding an object on which at least two marks for position detection in a predetermined two-dimensional plane are respectively formed at predetermined positions and movable in the two-dimensional plane;
A first detection system for detecting position information in the two-dimensional plane of each mark on the object held on the stage;
A transport device that receives and transports the object held on the stage;
A holding device that receives and holds the object conveyed from the stage by the conveying device from the conveying device;
Second position detecting position information of each mark in the two-dimensional plane with the object held by the holding device, and detecting position information of the object in the two-dimensional plane based on the detection result. A detection system;
Based on the detection result of the first detection system and the detection result of the second detection system obtained before and after trying to convey the object from the stage to the holding device at least once, the first detection system And a calculation device that calculates information relating to a deviation between the first coordinate system defined by the detection result and the second coordinate system defined by the detection result of the second detection system.   When a new object is transported from the stage to the holding device, an adjustment device is further provided that adjusts the position of the stage that holds the object in the two-dimensional plane based on the calculation result of the calculation device. The alignment apparatus according to claim 1.   3. The information on the deviation between the first coordinate system and the second coordinate system includes a positional deviation amount and a rotational deviation amount of the origin between the first coordinate system and the second coordinate system. The alignment device described in 1. The calculation device includes:
The stage holding the object is moved a predetermined distance in at least one predetermined direction in the two-dimensional plane, and position information of at least one mark on the object before and after the movement is detected by the first detection system. And based on the detection result, calculate information on rotational deviation between the first coordinate system and the third coordinate system defined by the movement of the stage,
The adjusting device is
4. The position according to claim 2, wherein information on a rotational deviation between the first coordinate system and the third coordinate system is taken into account when adjusting the position of the stage in the two-dimensional plane. Alignment device. The calculation device includes:
The stage holding the object is sequentially moved in a plurality of directions in the two-dimensional plane, the position information of the mark before and after the movement is detected by the first detection system, and based on the detection result, 5. The alignment according to claim 4, wherein an average of rotational deviation amounts of the first coordinate system and the third coordinate system respectively calculated for movement in each direction is calculated as information on the rotational deviation. apparatus. The plurality of directions include the axial direction of each coordinate axis of the third coordinate system defined by the movement of the stage,
The calculation device includes:
The position information of the mark before and after the movement of the stage in each axial direction is detected by the first detection system, and based on the detection result, the orthogonality of the coordinate axes of the third coordinate system is calculated,
The adjusting device is
The alignment apparatus according to claim 5, wherein when adjusting the position of the stage in the two-dimensional plane, the orthogonality of the coordinate axes of the third coordinate system is taken into consideration. The calculation device includes:
The stage holding the object is rotated by a predetermined angle in the two-dimensional plane around a predetermined reference point, and the position information of the mark before and after the rotation is detected by the first detection system. On the basis of the position coordinates of the reference point on the first coordinate system,
The adjusting device is
The adjustment of the position of the stage in the two-dimensional plane takes into account the deviation between the center position of the object calculated from the position information of each mark and the reference point. The alignment apparatus as described in any one of 2-6. The first detection system is a detection system that includes a plurality of imaging devices that respectively capture the marks, and detects position information of the marks based on imaging results of the imaging devices.
The calculation device includes:
The position information of each calibration mark is simultaneously detected by the first detection system in a state where the object including at least three calibration marks for two-dimensional position detection is held on the stage, and the detection is performed. Based on the result and the design formation position of each calibration mark, the calibration information of each imaging device is calculated,
The adjusting device is
8. The alignment apparatus according to claim 2, wherein calibration information of each imaging apparatus is taken into account when adjusting the position of the stage in the two-dimensional plane.   The calibration information of each imaging device includes an imaging magnification of the imaging device, a positional deviation amount and a rotational deviation amount of the origin between the coordinate system defined by the imaging result of the imaging device and the first coordinate system. The alignment apparatus according to claim 8, wherein the alignment apparatus is characterized in that: An alignment device for aligning an object,
A stage capable of holding an object on which at least one mark for position detection in a predetermined two-dimensional plane is formed at a predetermined position and movable in the two-dimensional plane;
A detection system for detecting position information in the two-dimensional plane of each mark on the object held on the stage;
A transport device that receives and transports the object held on the stage;
A holding device that receives and holds the object conveyed from the stage by the conveying device from the conveying device;
With the object held, the stage is moved a predetermined distance in at least one predetermined direction in the two-dimensional plane, and the position information of the mark before and after the movement is detected by the detection system, and the detection result And a calculation device for calculating information on rotational deviation between the detection coordinate system defined by the detection result of the detection system and the stage coordinate system defined by the movement of the stage;
An adjustment device that adjusts the position of the stage that holds the object in the two-dimensional plane based on the calculation result when carrying a new object from the stage to the holding device. apparatus. The calculation device includes:
The stage holding the object is sequentially moved in a plurality of directions in the two-dimensional plane, and the position information of the mark before and after the movement is detected by the detection system, and each movement is performed based on the detection result. 11. The alignment apparatus according to claim 10, wherein an average of rotational deviation amounts of the detection coordinate system and the stage coordinate system calculated for each of the information is calculated as information related to the rotational deviation. The plurality of directions include the axial direction of each coordinate axis of the stage coordinate system defined by the movement of the stage,
The calculation device includes:
The position information of the mark before and after the movement of the stage in each axial direction is detected by the detection system, and based on the detection result, the orthogonality of the coordinate axes of the stage coordinate system is calculated,
The adjusting device is
The alignment apparatus according to claim 11, wherein when the position of the stage in the two-dimensional plane is adjusted, the orthogonality of the coordinate axes of the stage coordinate system is taken into consideration. An exposure apparatus that irradiates a mask with an energy beam and transfers a pattern formed on the mask onto a photosensitive object via a projection optical system,
The alignment apparatus according to any one of claims 1 to 12, wherein at least one of the mask and the photosensitive object is the object.
A transfer device for transferring a pattern formed on the mask onto the photosensitive object via the projection optical system in a state where at least one of the mask and the photosensitive object is held by the holding device of the alignment device; An exposure apparatus. An alignment method for aligning an object,
A first step of holding an object on which at least two marks for position detection in a predetermined two-dimensional plane are respectively formed at predetermined positions on a stage movable in the two-dimensional plane;
A second step of detecting position information in the two-dimensional plane of each mark on the object held on the stage by a first detection system;
A third step of receiving the object from the stage, transporting and delivering the object to a holding device, and holding the object on the holding device;
The position information of each mark in the two-dimensional plane is detected in a state where the object is held by the holding device, and the position information of the object in the two-dimensional plane is detected based on the detection result. A fourth step of detecting by:
Detection result of the first detection system and detection of the second detection system obtained before and after trying the first step, the second step, the third step, and the fourth step at least once. Based on the relationship with the result, information on a deviation between the first coordinate system defined by the detection result of the first detection system and the second coordinate system defined by the detection result of the second detection system is calculated. The fifth step;
A sixth step of adjusting the position of the stage holding the object in the two-dimensional plane based on the calculation result when carrying a new object from the stage to the holding device; Including alignment method. An alignment method for aligning an object,
A first step of holding an object on which at least one mark for position detection in a predetermined two-dimensional plane is formed at a predetermined position on a stage movable in the two-dimensional plane;
A second step of detecting position information in the two-dimensional plane of each mark on the object held on the stage by a detection system;
With the object held on the stage, the stage is moved a predetermined distance in at least one predetermined direction in the two-dimensional plane, and the position information of the mark before and after the movement is detected by the detection system, and the detection is performed. A third step of calculating information on rotational deviation between the coordinate system defined by the detection result of the detection system and the coordinate system defined by the movement of the stage based on the result;
A fourth step of adjusting the position of the stage in the two-dimensional plane based on the calculation result when transporting a new object from the stage to a holding device capable of holding the object; Including alignment method. An exposure method for irradiating a mask with an energy beam and transferring a pattern formed on the mask onto a photosensitive object via a projection optical system,
A step of aligning at least one of the mask and the photosensitive object using the alignment method according to claim 14 or 15;
And transferring the pattern formed on the mask onto the photosensitive object via the projection optical system after at least one of the mask and the photosensitive object is aligned. In a device manufacturing method including a lithography process,
In the lithography process, exposure is performed using the exposure method according to claim 16. It is defined by detection results of a plurality of first detection systems that respectively detect position information in the two-dimensional plane of at least two marks on a pattern forming reticle held on a stage movable in the two-dimensional plane. And a plurality of second detection systems for detecting position information in the two-dimensional plane of the marks on the pattern forming reticle carried from the stage and held by a holding device. A calibration reticle used to determine information about deviations from the second coordinate system defined by the results,
Having at least two mark areas,
Each of the mark areas has an arrangement relationship such that when the calibration reticle is held on the stage, each mark area is within the detection field of view of the plurality of first detection systems, and the calibration reticle is the holding device. Formed on the calibration reticle in an arrangement relationship so as to be within the detection field of view of the plurality of second detection systems when held on
Each of the plurality of mark regions includes a first mark having the same shape as the mark formed on the pattern forming reticle, and at least three calibration marks for detecting a two-dimensional position arranged with reference to the first mark. And a calibration reticle.

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