JP2015018903A - Mark detection method and device, and exposure method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively detect a mark when the mark is provided on a rear surface of a substrate.SOLUTION: A mark detection device 8 for detecting a mark 46 formed on a rear surface of a wafer W, comprises: a wafer stage WST for holding a wafer W when the wafer W is irradiated with an exposure light; a wafer transfer device 66 for temporarily holding the wafer W before the wafer W is placed on the wafer stage WST; and a mark detection part 52 for detecting location information of the mark 46 on the rear surface of the wafer W in a state that the wafer W is held on the wafer transfer device 66.

Description

  The present invention relates to a mark detection technique for detecting a mark provided on a substrate, an exposure technique using the mark detection technique, and a device manufacturing technique using the exposure technique.

  As a substrate to be exposed by an exposure apparatus such as a so-called stepper or scanning stepper used in a photolithography process for producing an electronic device (microdevice) such as a semiconductor element, a disk-shaped semiconductor wafer (hereinafter simply referred to as a wafer) There is.) In order to increase the throughput (productivity) when manufacturing electronic devices, the SEMI (Semiconductor Equipment and Materials International) standard (SEMI standards) of the diameter of the wafer is almost 125 mm, 150 mm, 200 mm, and 300 mm every few years. It is increasing at a rate of 1.25 to 1.5 times.

  Further, a notch or an orientation flat as a notch for detecting the rotation angle on the basis of the outer shape is formed at the edge portion of the conventional wafer. When the wafer is loaded into the exposure apparatus, the position of the notch portion of the wafer is detected in advance by a pre-alignment system, and rough adjustment of the rotation angle of the wafer is performed based on this result ( For example, see Patent Document 1).

U.S. Patent No. 6225012

  Recently, in order to further increase the throughput when manufacturing electronic devices, the SEMI standard has standardized a wafer having a diameter of 450 mm. In addition to the wafer having a diameter of 450 mm, it has been conventionally known that if a notch for detecting the rotation angle of the wafer is provided at the edge, the wafer may be distorted. Therefore, in order to detect the rotation angle of the wafer having a diameter of 450 mm, it is considered to provide a small mark made of, for example, a recess on the back surface.

  In this regard, the wafer is conventionally transported to the exposure apparatus with the back surface supported, and the pre-alignment system detects the notch of the wafer from the front surface (surface on which the device pattern is formed) side of the wafer. For this reason, it is difficult to detect the mark provided on the back surface of the wafer with the conventional technique. Furthermore, in order to increase the throughput, it is necessary to detect such marks as efficiently as possible.

  In view of such circumstances, an aspect of the present invention aims to enable efficient detection of a mark when the mark is provided on the back surface of the substrate.

  According to the first aspect, there is provided a mark detection device for detecting a first mark formed on the back surface of a substrate, the substrate stage holding the substrate when the substrate is irradiated with exposure light, and the substrate Before the substrate is placed on the stage, the substrate holding unit that temporarily holds the substrate, and the position information of the first mark is detected while the substrate is held by the substrate holding unit. And a mark detection device including the detection unit.

  According to the second aspect, in the exposure apparatus that illuminates the pattern with the exposure light and exposes the substrate with the exposure light through the pattern and the projection optical system, the mark detection apparatus according to the first aspect and the mark detection thereof An exposure apparatus is provided that includes a control unit that corrects at least one of the position and rotation angle of the substrate based on the position information of the first mark formed on the back surface of the substrate detected by the apparatus.

  According to the third aspect, there is provided a mark detection method for detecting a first mark formed on the back surface of a substrate, wherein the substrate is placed on a substrate stage that holds the substrate before exposure light is irradiated. Before holding the substrate temporarily by the substrate holding unit, and detecting the position information of the first mark in a state where the substrate is held by the substrate holding unit. A detection method is provided.

  According to the fourth aspect, in the exposure method of illuminating the pattern with the exposure light and exposing the substrate through the pattern with the exposure light, the pattern is formed on the back surface of the substrate using the mark detection method of the third aspect. Detecting the position information of the first mark, placing the substrate on the substrate stage, and at least the position and rotation angle of the substrate based on the position information detected by the mark detection method. An exposure method is provided that includes correcting one.

  According to a fifth aspect, the method includes forming a pattern of a photosensitive layer on a substrate using the exposure apparatus or the exposure method according to the aspect of the present invention, and processing the substrate on which the pattern is formed. A device manufacturing method is provided.

  According to the aspect of the present invention, since the position information of the mark (first mark) on the back surface of the substrate is detected while the substrate is held by the substrate holder, the mark can be detected efficiently. .

It is the figure which represented a part showing schematic structure of the exposure apparatus which concerns on 1st Embodiment in the cross section. It is a top view which shows the wafer stage in FIG. 2 is a block diagram showing a control system and the like of the exposure apparatus of FIG. (A) is a plan view showing the surface of the wafer, (B) is an enlarged view showing a mark on the back surface of the wafer, (C) is a cross-sectional view of FIG. 4 (B), and (D) is an enlarged view showing a mark of a modification. (E) is an enlarged view showing a mark of another modified example, (F) is a plan view showing a notch of the wafer of the first conventional example, and (G) is a notch of the wafer of the second conventional example. It is a top view which shows a part. (A) is a top sectional view showing a mechanism part of the mark detection device in FIG. 1, and (B) is a sectional view taken along line BB in FIG. 5 (A). It is a figure which shows the mark detection part in FIG.5 (B). It is a flowchart which shows an example of the exposure method containing the mark detection method. (A) is a top view which shows the state which transferred the wafer from the transfer arm to the wafer delivery apparatus, (B) is sectional drawing which follows the BB line of FIG. 8 (A). (A) is a plan view showing another arrangement example of the mark detection unit, (B) is a plan view showing yet another arrangement example of the mark detection unit, and (C) is another configuration example of the drive mechanism of the mark detection unit. FIG. (A) is a diagram showing a mark detection unit of the first modification, (B) is a partially enlarged view showing the vicinity of the edge portion of the wafer in FIG. 10 (A), (C) is in FIG. 10 (B). It is a bottom view which shows a partial reflection mirror. (A) is a figure which shows the mark detection part of a 2nd modification, (B) is the elements on larger scale which show the image pick-up element and glass plate for optical path length correction | amendment in FIG. 11 (A). (A) is a diagram showing a mark detection unit of the third modification, (B) is a partially enlarged view showing the vicinity of the edge portion of the wafer in FIG. 12 (A), (C) is in FIG. 12 (B). It is a top view which shows the surface of a prism. (A) is a diagram showing a part of the mechanism portion of the mark detection apparatus according to the second embodiment in section, (B) is a diagram showing a state where the wafer stage is moved from the state of FIG. 13 (A). is there. It is the figure which represented in part the section which shows the mechanism part of the mark detection apparatus of a modification. It is a flowchart which shows an example of the manufacturing method of an electronic device.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS. 1 to 8B. FIG. 1 shows a schematic configuration of an exposure apparatus EX provided with a mark detection apparatus according to the present embodiment. The exposure apparatus EX is a scanning exposure type projection exposure apparatus composed of a scanning stepper (scanner). The exposure apparatus EX includes a projection optical system PL (projection unit PU). Hereinafter, the Z axis is taken in parallel to the optical axis AX of the projection optical system PL, the Y axis is set in the direction in which the reticle R and the wafer (semiconductor wafer) W are relatively scanned in a plane orthogonal to the Z axis, the Z axis and the Y axis. The description will be made by taking the X axis in a direction perpendicular to the axis. In addition, the rotation directions around the axes parallel to the X axis, the Y axis, and the Z axis are also referred to as θx, θy, and θz directions. In the present embodiment, the plane orthogonal to the Z axis (XY plane) is substantially parallel to the horizontal plane.

  The exposure apparatus EX includes, for example, an illumination system ILS disclosed in, for example, US Patent Application Publication No. 2003/0025890, and illumination light (exposure light) IL (for example, an ArF excimer laser having a wavelength of 193 nm) from the illumination system ILS. A reticle stage RST that holds and moves a reticle R (mask) illuminated by light or a harmonic of a solid-state laser (such as a semiconductor laser). Further, the exposure apparatus EX includes a projection unit PU including a projection optical system PL that exposes the wafer W (substrate) with the illumination light IL emitted from the reticle R, a wafer stage WST that holds and moves the wafer W, and a wafer. A main control device 20 comprising a mark detection device 8 as a pre-alignment system for detecting the position information of the wafer W including the position information of the W mark (including angle information, the same applies hereinafter), and a computer for controlling the operation of the entire device. (See FIG. 3). Further, since the positions of reticle stage RST and wafer stage WST are defined by the coordinate system (X, Y, Z) composed of the X axis, Y axis, and Z axis, this coordinate system (X, Y, Z). ) Is also referred to as a stage coordinate system.

  The reticle R is held on the upper surface of the reticle stage RST by vacuum suction or the like, and a circuit pattern or the like is formed on the pattern surface (lower surface) of the reticle R. The reticle stage RST can be finely driven in an XY plane on a reticle base (not shown) by a reticle stage drive system 25 shown in FIG. 3 including, for example, a linear motor and the like, and scanning designated in the scanning direction (Y direction). It can be driven at speed.

  Position information within the moving surface of the reticle stage RST (including the position in the X direction, the Y direction, and the rotation angle in the θz direction) is transferred to the moving mirror 22 (or mirror-finished) by the reticle interferometer 24 including a laser interferometer. For example, it is always detected with a resolution of about 0.5 to 0.1 nm via the stage end face. The measurement value of reticle interferometer 24 is sent to main controller 20 in FIG. Main controller 20 controls reticle stage drive system 25 based on the measurement value, thereby controlling the position and speed of reticle stage RST.

  In FIG. 1, the projection unit PU disposed below the reticle stage RST includes a lens barrel 40 and a projection optical system PL having a plurality of optical elements held in a predetermined positional relationship within the lens barrel 40. A flat frame (hereinafter referred to as a measurement frame) 16 is supported by a frame mechanism (not shown) via a plurality of vibration isolation devices (not shown), and the projection unit PU is formed on the measurement frame 16. It is installed in the opening via a flange portion FL. The projection optical system PL is, for example, telecentric on both sides (or one side on the wafer side) and has a predetermined projection magnification β (for example, a reduction magnification such as 1/4 or 1/5).

  When the illumination area IAR of the reticle R is illuminated by the illumination light IL from the illumination system ILS, the image of the circuit pattern in the illumination area IAR is projected via the projection optical system PL by the illumination light IL that has passed through the reticle R. It is formed in an exposure area IA (an area optically conjugate with the illumination area IAR) of one shot area of W. For example, the wafer W is obtained by applying a photoresist PR (photosensitive material) with a thickness of about several tens to 200 nm to a large disk-shaped substrate SU made of a semiconductor such as silicon and having a diameter of 450 mm (FIG. 10). 4 (C)). That is, as an example, the wafer W is a 450 mm wafer. The thickness of a substrate having a diameter of 450 mm is currently assumed to be, for example, about 900 to 1100 μm (for example, about 925 μm).

  When the wafer W is a 450 mm wafer, as shown in FIG. 4A, a form in which a notch portion is not provided in the circular edge portion of the wafer W has been studied. That is, in the wafer W shown in FIG. 4A, notches such as notches and orientation flats are not provided in the edge portions described above. In this case, the surface Wa of the wafer W (the surface on which the photoresist PR of the substrate SU is applied) is regularly divided into a large number of shot areas SA vertically and horizontally, and a device pattern DP is formed in each shot area SA. The If the shot area SA is about 26 mm wide and about 33 mm long, for example, about 180 shot areas SA are formed on the surface Wa of the wafer W, for example. In the first exposure of the wafer W, the surface Wa of the wafer W is not partitioned into the shot area SA.

  Further, a surface facing the front surface Wa of the wafer W or a surface of the base material SU of the wafer W on which the photoresist PR is not applied is referred to as a back surface Wb of the wafer W. 4B shows a part of the back surface Wb of the wafer W, and FIG. 4C is a cross-sectional view of FIG. As shown in FIGS. 4B and 4C, when the wafer W is a 450 mm wafer, the wafer W is located within the peripheral region 47 from the edge Wf of the back surface Wb of the wafer W to, for example, about 1 mm to several mm. A mark 46 composed of a plurality of small recesses 46a in a row is formed along the radial direction of W. As an example, the recess 46a has a circular shape with a diameter of about 100 μm and a depth of about 20 to 70 μm. In FIG. 4C, the recess 46a is cylindrical, but the recess 46a may be hemispherical. As an example, the direction of the mark 46 (the direction along a straight line passing through the centers of the plurality of recesses 46a) is set to a predetermined angle, for example, parallel to the direction of one crystal axis of the substrate SU of the wafer W. May be. Further, the shot area SA may be formed so that the direction of the mark 46 and the longitudinal direction (or short direction) of the shot area SA on the surface of the wafer W are parallel to each other.

  As an example, the mark 46 can be formed by cutting with a fine drill or irradiation with a processing laser beam. Further, the mark 46 can be formed by a lithography process including partial photoresist coating on the back surface Wb of the wafer W, exposure of the mark pattern, development, etching, and resist stripping. In the mark 46, a plurality of concave portions 46a may be formed in a plurality of rows in the radial direction. Further, the mark 46 may be formed by forming a plurality of recesses 46 a in a single row or in a plurality of rows in a circumferential direction parallel to the edge portion of the wafer W. Also, instead of the mark 46, as shown in FIG. 4D, a plurality of rows (or even one row) of partial marks 46A1 and 46A2 in which a plurality of recesses are arranged in the radial direction of the wafer W, and a plurality of recesses are formed on the wafer. A mark 46A including one row (or a plurality of rows) of mark portions 46A3 arranged in the circumferential direction of W may be used. Further, instead of the mark 46, as shown in FIG. 4E, a mark 46B made up of one or a plurality of elongated concave portions arranged along the radial direction (or circumferential direction) of the wafer W is used. Also good.

  In this embodiment, the mark 46 is formed at one place on the back surface Wb of the wafer W, but the number of the mark 46 is not particularly limited, and a plurality of marks 46 such as three may be formed. In addition, when a plurality of marks 46 are formed on the back surface Wb, it is preferable that the shapes are different in order to distinguish each mark. For example, in the case where a plurality of marks 46 shown in FIG. 4D are provided on the back surface Wb, the height of the mark portion 46A3 (the distance from the edge of the wafer W) among the marks 46 may be varied. As a result, the marks 46 formed on the back surface Wb of the wafer W can be individually identified. For example, in the case where a plurality of marks having a shape in which the mark portion 46A3 shown in FIG. 4D is added to the mark 46 in FIG. It is desirable to vary the height of the mark portion 46A3 (distance from the edge of the wafer W).

  In the exposure apparatus EX of FIG. 1, in order to perform exposure using the liquid immersion method, the lens barrel 40 that holds the tip lens 91 that is the optical element on the most image plane side (wafer W side) constituting the projection optical system PL is used. A nozzle unit 32 that constitutes a part of the local liquid immersion device 38 is provided so as to surround the lower end portion. The nozzle unit 32 is connected to a liquid supply device 34 and a liquid recovery device 36 (see FIG. 3) via a supply tube 31A and a recovery tube 31B for supplying an exposure liquid Lq (for example, pure water). . If the immersion type exposure apparatus is not used, the local immersion apparatus 38 may not be provided.

  The exposure apparatus EX also aligns the wafer W with an aerial image measurement system (not shown) that measures the position of the image of the alignment mark (reticle mark) of the reticle R by the projection optical system PL in order to align the reticle R. For example, an image processing system (FIA system) alignment system AL, an irradiation system 90a and a light receiving system 90b, and a multi-point oblique incidence system that measures Z positions at a plurality of locations on the surface of the wafer W. An autofocus sensor (hereinafter referred to as a multi-point AF system) 90 (see FIG. 3) and an encoder 6 (see FIG. 3) for measuring position information of wafer stage WST are provided. The aerial image measurement system is provided in, for example, wafer stage WST. The alignment system AL is a predetermined wafer mark selected from the alignment marks (wafer marks) attached to each shot area SA on the surface Wa of the wafer W when the second and subsequent layers of the wafer W are exposed. Used to detect the position of

  As shown in FIG. 2, the alignment system AL is, for example, in the X direction (non-scanning direction) in a region about the diameter of the wafer W arranged away from the projection optical system PL in the −Y direction. Consists of five-lens alignment systems ALc, ALb, ALa, ALd, and ALe arranged at approximately equal intervals, and is configured so that wafer marks at different positions on the wafer W can be detected simultaneously by the five-lens alignment systems ALa to ALe. ing. In addition, the loading that is the center position of wafer stage WST when loading wafer W at a position away from −Y direction with respect to alignment systems ALa to ALe and shifted to −X direction and + X direction to some extent. The position LP and the unloading position UP, which is the center position of the wafer stage WST when the wafer W is unloaded, are set. As shown in FIG. 1, a wafer transfer device 66 is arranged above the loading position LP (+ Z direction).

  As an example, the main body 67 of the wafer transfer device 66 is supported by a frame member FR1 supported independently of the measurement frame 16 so as to be movable in the Z direction. Further, near the loading position LP, a wafer transfer robot WLD for loading the wafer W into the exposure apparatus EX from the coater / developer (not shown) side is installed. As an example, the wafer transfer robot WLD includes a main body portion 64 installed on a floor surface, first and second intermediate arms 63 and 62 provided so as to be sequentially rotatable with respect to the main body portion 64, and a second intermediate portion. A fork-shaped transfer arm 61 (see FIG. 8A) is provided rotatably at the tip of the arm 62 and holds and transfers the wafer W by vacuum suction. The transfer arm 61 of the wafer transfer robot WLD transfers the wafer W placed on a rotary table (not shown) installed on the −Y direction side to below the wafer transfer device 66. The operations of the wafer transfer device 66 and the wafer transfer robot WLD are controlled by the transfer control system 50 (see FIG. 3).

  Further, the mark 46 (see FIG. 4B) formed on the back surface of the wafer W around the main body 67 of the wafer transfer device 66 and the position information of the edge portion in the vicinity thereof (including angle information, the same applies hereinafter). A mark detection unit 52 that detects the position of the wafer W and two edge detection units 53A and 53B that detect position information of two different edge portions of the wafer W are disposed. As an example, the mark detection unit 52 captures an image of the mark 46 in the test region on the back surface of the wafer W shown in FIGS. 4A and 4B, and at the same time, an image of the edge portion of the wafer W near the mark 46. Image. The test area FVB by the mark detection unit 52 in FIG. 4A is substantially the first test area (first field of view) including the mark 46 on the back surface of the wafer W, and the edge near the mark 46. This is a region combining the second region to be examined (second visual field) including the portion. The edge detection units 53A and 53B capture the image of the edge portion of the wafer W with the two test regions (fields of view) FVA2 and FVA1 at positions obtained by dividing the edge portion of the wafer W together with the test region FVB at substantially equal angular intervals. To do. Detection signals from the mark detection unit 52 and the edge detection units 53A and 53B are supplied to the calculation unit 55 (see FIG. 3). The computing unit 55 processes these detection signals to position the center of the wafer W in the X and Y directions, and the rotation angle of the wafer W (for example, the direction parallel to the mark 46 on the wafer W and the stage coordinate system (X , Y, Z) is calculated and an angle formed by an axis parallel to the Y axis is supplied to the main controller 20. A storage unit 56 such as a magnetic storage device is connected to the calculation unit 55.

  The mark detection device 8 includes the wafer stage WST, wafer transfer device 66, transfer control system 50, mark detection unit 52, edge detection units 53A and 53B, calculation unit 55, and storage unit 56. The main controller 20 can perform pre-alignment, for example, correction of the rough position and rotation angle of the wafer W, using the center position and rotation angle of the wafer W supplied from the calculation unit 55. The detailed configuration and operation of the mark detection device 8 will be described later. The transport control system 50 and the calculation unit 55 may have different functions on the software of the computer that constitutes the main control device 20.

  Further, another wafer delivery device (not shown) used when unloading the wafer W is disposed above the unloading position UP in FIG. 2, and unloaded near the unloading position UP. Another wafer transfer robot (not shown) for unloading the wafer W to the coater / developer side is arranged. The wafer transfer device 66 can also be used as the wafer transfer device for unloading.

  In FIG. 2, the irradiation system 90 a and the light receiving system 90 b of the multipoint AF system 90 are arranged along a region between the alignment systems ALa to ALe and the projection optical system PL as an example. With this configuration, after loading the wafer W onto the wafer stage WST at the loading position LP, the wafer stage WST is driven to move the wafer W from the exposure start position below the projection optical system PL substantially in the Y direction. In addition, the measurement of the Z position distribution on the wafer surface by the multi-point AF system 90 and the position measurement of a plurality of wafer marks on the wafer surface by the alignment systems ALa to ALe can be efficiently performed. The measurement results of the multipoint AF system 90 and the alignment system AL are supplied to the main controller 20.

  In FIG. 1, wafer stage WST is supported in a non-contact manner on an upper surface WBa parallel to the XY plane of base board WB via a plurality of unillustrated vacuum preload type static air bearings (air pads), for example. Wafer stage WST can be driven in the X and Y directions by a stage drive system 18 (see FIG. 3) including, for example, a planar motor or two sets of orthogonal linear motors. Wafer stage WST is provided in stage main body 30 driven in X and Y directions, wafer table WTB as a Z stage portion mounted on stage main body 30, and in stage main body 30. A Z stage drive unit that relatively finely drives the Z position of wafer table WTB and the tilt angles in the θx direction and θy direction is provided. A wafer holder 44 for holding the wafer W on a mounting surface substantially parallel to the XY plane by vacuum suction or the like is provided inside the central opening of the wafer table WTB.

In addition, a large number of protrusions are formed on the upper surface of the wafer holder 44 in an area surrounded by a ring-shaped side wall, and as an example, an approximately equal angle along a circumference set to surround the center in the area. Bar-shaped members (hereinafter referred to as center pins) CP1, CP2, CP3 (see FIG. 5B) that can be moved up and down in the Z direction to deliver the wafer W to three locations (or 6 locations, etc.) at intervals. Is provided. In a state where the wafer W is placed on the placement surface (the surface of many protrusions) of the wafer holder 44, the tip portions of the center pins CP1 to CP3 are retracted to the back side of the wafer W.
In the present embodiment, a portion (Z stage portion) including wafer table WTB and wafer holder 44 of wafer stage WST is configured to be rotatable with respect to stage main body 30 by an angle designated in the θz direction. The main controller 20 controls the rotation angle in the θz direction of the Z stage portion via the stage drive system 18. Instead of rotating only the Z stage part, the stage body 30 and the Z stage part as a whole may be rotated in the θz direction.

Further, the upper surface of wafer table WTB has a surface that is substantially flush with the surface of wafer W and has been subjected to a liquid repellency treatment with respect to liquid Lq, and has a rectangular outer shape (contour) and a central portion of wafer W. A flat plate-like plate body 28 having a high flatness in which a circular opening that is slightly larger than the mounting area is formed.
In the configuration of the so-called immersion type exposure apparatus provided with the above-mentioned local immersion apparatus 38, the plate body 28 further has an outer shape (see FIG. 2) surrounding the circular opening 28a. It has a rectangular (contour) and a plate portion (liquid repellent plate) 28b whose surface has been subjected to a liquid repellent treatment, and a peripheral portion 28e surrounding the plate portion 28b. A pair of two-dimensional diffraction gratings 12A and 12B elongated in the X direction so as to sandwich the plate portion 28b in the Y direction are fixed on the upper surface of the peripheral portion 28e, and elongated in the Y direction so as to sandwich the plate portion 28b in the X direction. A pair of two-dimensional diffraction gratings 12C and 12D is fixed. The diffraction gratings 12 </ b> A to 12 </ b> D are reflection type diffraction gratings on which a two-dimensional grating pattern having a period of about 1 μm with the X direction and the Y direction as periodic directions is formed.

  In FIG. 1, the measurement grating 16 is irradiated with measurement laser light (measurement light) on the diffraction gratings 12 </ b> C and 12 </ b> D so that the projection optical system PL is sandwiched in the X direction on the bottom surface of the measurement frame 16. A plurality of triaxial detection heads 14 for measuring a three-dimensional relative position in the direction and the Z direction are fixed. Further, the measurement laser beam is irradiated to the diffraction gratings 12A and 12B so that the projection optical system PL is sandwiched in the Y direction on the bottom surface of the measurement frame 16, and the three-dimensional relative position with respect to the diffraction grating is measured. A plurality of triaxial detection heads 14 are fixed (see FIG. 2). Furthermore, one or a plurality of laser light sources (not shown) for supplying laser light (measurement light and reference light) to the plurality of detection heads 14 are also provided.

  In FIG. 2, during the period in which the wafer W is exposed through the projection optical system PL, any two detection heads 14 in the line A1 in the Y direction irradiate the diffraction grating 12A or 12B with measurement light, and perform diffraction. A detection signal of interference light between the diffracted light generated from the gratings 12A and 12B and the reference light is supplied to the corresponding measurement calculation unit 42 (see FIG. 3). In parallel with this, any two detection heads 14 in one row A2 in the X direction irradiate measurement light to the diffraction grating 12C or 12D, and interference light between the diffraction light generated from the diffraction gratings 12C and 12D and the reference light. Is supplied to the corresponding measurement calculation unit 42 (see FIG. 3). In the measurement calculation unit 42 for the detection heads 14 in one column A1 and one row A2, the relative positions of the wafer stage WST (wafer W) and the measurement frame 16 (projection optical system PL) in the X, Y, and Z directions ( Relative movement amount) is obtained with a resolution of 0.5 to 0.1 nm, for example, and the obtained measurement values are supplied to the switching units 92A and 92B. In the measurement value switching units 92 </ b> A and 92 </ b> B, information on the relative position supplied from the measurement calculation unit 42 corresponding to the detection head 14 facing the diffraction gratings 12 </ b> A to 12 </ b> D is supplied to the main controller 20.

  A plurality of detection heads 14 in one column A1 and one row A2, a laser light source (not shown), a plurality of measurement calculation units 42, switching units 92A and 92B, and diffraction gratings 12A to 12D constitute a three-axis encoder 6. . The detailed configuration of such an encoder and the above-described five-eye alignment system is disclosed in, for example, US Patent Application Publication No. 2008/094593. Based on the relative position information supplied from encoder 6, main controller 20 determines the position of wafer stage WST (wafer W) in the X, Y, and Z directions with respect to measurement frame 16 (projection optical system PL), and Information such as the rotation angle in the θz direction is obtained, and wafer stage WST is driven via stage drive system 18 based on this information.

A laser interferometer that measures the three-dimensional position of wafer stage WST is provided in parallel with encoder 6 or instead of encoder 6, and wafer stage WST is driven using the measured value of this laser interferometer. May be.
Then, at the time of exposure of the exposure apparatus EX, the reticle R and the wafer W are first aligned as a basic operation. Thereafter, irradiation of the reticle R with the illumination light IL is started, and an image of a part of the pattern of the reticle R is projected onto one shot area on the surface of the wafer W via the projection optical system PL, while the reticle stage RST. The pattern image of the reticle R is transferred to the shot area by a scanning exposure operation that moves the wafer stage WST in synchronization with the Y direction using the projection magnification β of the projection optical system PL as a speed ratio (synchronous scanning). Thereafter, by repeating the operation (step movement) of moving the wafer W in the X and Y directions via the wafer stage WST and the above scanning exposure operation, for example, by the immersion method and the step-and-scan method. The pattern image of the reticle R is transferred to the entire shot area of the wafer W.

  At this time, in the detection head 14 of the encoder 6, since the optical path lengths of the measurement light and the diffracted light are shorter than those of the laser interferometer, the influence of the air fluctuation on the measurement value is very small as compared with the laser interferometer. Therefore, the pattern image of the reticle R can be transferred to the wafer W with high accuracy. In the present embodiment, the detection head 14 is disposed on the measurement frame 16 side, and the diffraction gratings 12A to 12D are disposed on the wafer stage WST side. As another configuration, the diffraction gratings 12A to 12D may be disposed on the measurement frame 16 side, and the detection head 14 may be disposed on the wafer stage WST side.

Next, the configuration and operation of the mark detection apparatus 8 of this embodiment for detecting the position information of the wafer W including the position information of the mark 46 on the back surface of the wafer W will be described in detail.
5A is a plan view showing a mechanism part of the mark detection device 8 in FIG. 1, and FIG. 5B is a cross-sectional view taken along line BB in FIG. 5A. Note that FIG. 5A is also a cross-sectional view taken along the line AA in FIG. The mechanism unit of the mark detection device 8 includes a wafer stage WST, a wafer transfer device 66, a mark detection unit 52, and edge detection units 53A and 53B. In FIG. 5B, the wafer transfer device 66 is fixed to the disc-shaped main body 67 and the upper surface of the main body 67, and is disposed so as to be movable in the Z direction within the opening formed in the frame member FR1. The columnar slide member 69, a flange portion 69F fixed to the upper end of the slide member 69, and a plurality of actuators 70 for controlling the position of the flange portion 69F in the Z direction with respect to the frame member FR1. As the actuator 70, for example, a direct-acting screw mechanism or an air cylinder can be used, and a sensor (not shown) for measuring the Z position of the flange portion 69F is also mounted. The conveyance control system 50 in FIG. 3 drives the actuator 70 based on the measurement value of the sensor, so that the Z position of the main body 67 connected to the flange 69F via the slide member 69 can be controlled. An arbitrary mechanism other than the mechanism using the actuator 70 can be used as a mechanism for controlling the Z position of the main body 67.

  The main body 67 has a circular shape slightly larger than the wafer W. The wafer transfer device 66 includes a plurality of short columnar non-contact suction devices (hereinafter referred to as suction cups) 68 fixed to the bottom surface of the main body 67 and a side surface of the main body 67 at substantially equal angular intervals ( Here, the connecting members 71A, 71B, 71C (see FIG. 5A) fixed at intervals of 120 degrees (see FIG. 5A) and the rotating members 71Am, 71Bm, etc. are attached to the connecting members 71A, 71B, 71C so as to be rotatable. L-shaped suction portions 72A, 72B, 72C. The suction cup 68 can also be called a Bernoulli cup or a Bernoulli chuck. The tip portions of the suction portions 72A to 72C can be retracted in the side surface direction of the main body portion 67 by the corresponding motors 71Am and the like, as typically indicated by the dotted line position B5. Furthermore, the tip portions of the suction portions 72A to 72C can be rotated by the corresponding motors 71Am and the like until they are parallel to the bottom surface of the main body portion 67, and the wafer W is supported on the tip portions of the suction portions 72A to 72C in this state. Is possible. A vacuum suction hole (not shown) is provided at the tip of the suction parts 72A to 72C, and a gas is sucked from the hole by a vacuum pump (not shown) through a flexible pipe (not shown). Thus, the wafer W can be sucked and held.

  FIG. 5B shows a state in which the wafer W is held by the tip portions of the suction portions 72A to 72C so as to face the plurality of suction cups 68 on the bottom surface of the main body portion 67 with a predetermined interval. As shown in FIG. 5A, as an example, the plurality of suction cups 68 are arranged so as to face the center of the surface of the wafer W and a plurality of concentrically arranged positions. In FIG. 5A, the main body 67 is represented by a two-dot chain line.

  As indicated by an arrow B1, the suction cup 68 ejects clean gas at a variable flow rate substantially radially along the surface facing the wafer W. When the distance between the surface and the wafer W increases, Bernoulli increases. When the negative pressure due to the effect is generated and the wafer W is sucked to the suction cup 68 side and the distance between the surface and the wafer W is reduced, a force that separates the wafer W from the suction cup 68 is exerted by the pressure air cushion effect. As a result, the distance between the suction cup 68 and the wafer W can be maintained at a value corresponding to the flow rate of the gas without contact. Then, the transfer control system 50 controls the distance between the plurality of suction cups 68 and the wafer W independently of each other, so that the shape of the wafer W held in a substantially non-contact manner protrudes toward the wafer stage WST, for example. Can be set to any shape including a shape (hereinafter referred to as a downward convex shape). For example, the plurality of suction cups 68 hold the wafer W in a downward convex shape and hold it in a non-contact manner, move the wafer holder 44 of the wafer stage WST to the lower side of the wafer W, and move the tips of the suction portions 72A to 72C to the side surfaces of the main body 67. By retracting in the direction and driving the actuator 70 to lower the main body 67 toward the wafer holder 44, the large wafer W can be placed on the upper surface of the wafer holder 44 without being deformed.

  Further, the mark detection unit 52 includes a first optical system 54A fixed to the main body 67 in the vicinity of the connecting member 71A (adsorption unit 72A), and a Z direction along the −Y direction end of the first optical system 54A. The second optical system 54B is mounted so as to be movable, and the third optical system 54C is mounted on the suction portion 72A. The second optical system 54B can be moved in the Z direction between a position indicated by a solid line and a retracted position B2 indicated by a dotted line in FIG. Moreover, the edge detection parts 53A and 53B are being fixed to the main-body part 67 in the vicinity of the connection members 71B and 71C, respectively. Note that the first optical system 54A and the edge detection units 53A and 53B of the mark detection unit 52 may be fixed to the frame member FR1.

  FIG. 6 shows the mark detection unit 52 in FIG. In FIG. 6, a suction hole (not shown) is formed at the tip 72Ab of the suction part 72A, and the wafer W is placed on the tip 72Ab. In the present embodiment, the mark 46 is formed on the back surface of the wafer W between the front end portion 72Ab of the suction portion 72A and the edge portion of the wafer W. In addition, in FIG. 6, the shape of the adsorption | suction part 72A is simplified and represented. Further, the first optical system 54A of the mark detection unit 52 converts, for example, visible light (hereinafter referred to as detection light) DL, which is a wavelength region having low photosensitivity with respect to the photoresist on the wafer W, substantially in the −Z direction. It has a light source 73 that emits light. As an example, the light source 73 is a light emitting diode (LED), but a combination of a lamp and a light guide can be used as the light source 73.

  The first optical system 54A includes a first lens system 74A and a second lens system 74B for illumination for condensing and collimating the detection light DL emitted from the light source 73, and the collimated detection light DL is substantially −Y. A mirror M1 that reflects in the direction, and a half prism 76 that splits the detection light DL reflected by the mirror M1 into a first detection light DL1 that is substantially in the −Z direction and a second detection light DL2 that is substantially in the −Y direction. Have. Further, the first optical system 54A includes a first objective lens system 77A that condenses the first detection light DL1 in a region including the edge portion of the wafer W supported by the suction unit 72A, and the first objective lens system 77A. It has the 2nd objective lens 77B which forms an image formation optical system, and the two-dimensional image pick-up element 79, such as CCD type or CMOS type.

  The first optical system 54A includes an illumination aperture stop (hereinafter referred to as illumination σ stop) 75A disposed between the mirror M1 and the half prism 76, and the half prism 76 and the second objective lens system 77B. An imaging aperture stop 75B disposed therebetween, a third objective lens system 77C that condenses the second detection light DL2, and a mirror M2 that reflects the collected detection light DL2 substantially in the −Z direction. Have The first optical system 54A is supported by a lens barrel member (not shown). The second optical system 54B of the mark detection unit 52 includes a mirror M3 that reflects the second detection light DL2 reflected by the mirror M2 substantially in the + Y direction, and a support member (not shown) that supports the mirror M3. Have

  The third optical system 54C of the mark detection unit 52 includes a right-angle prism type reflection member 78 provided in a recess 72Ac formed adjacent to the distal end portion 72Ab of the suction portion 72A. An opening 72Aa for passing light passing between the mirror M3 and the reflecting member 78 is formed in the adsorption portion 72A. The reflecting member 78 reflects the second detection light DL2 reflected by the mirror M3 and passed through the opening 72Aa in a substantially + Z direction toward a region including the mark 46 on the back surface of the wafer W (total reflection surface) 78a. , And a partial reflection surface 78b substantially parallel to the XY plane. The partial reflection surface 78b reflects the first detection light DL1 incident from the first objective lens system 77A, and the second detection light DL2 reflected by the reflection surface 78a and directed to the region including the mark 46. It has a transmission surface 78d. In the present embodiment, the first imaging optical system including the objective lens systems 77A and 77B in the mark detection unit 52 in FIG. 6 with the wafer W held by the suction units 72A to 72C in FIG. The surface Wa of the wafer W and the light receiving surface of the image sensor 79 are optically conjugate. In the second imaging optical system including the objective lens systems 77C and 77B, the back surface Wb (the surface on which the mark 46 is formed) of the wafer W and the light receiving surface of the image sensor 79 are optically conjugate.

  In the mark detection unit 52, the first detection light DL1 branched by the half prism 76 passes outside the edge portion of the wafer W via the first objective lens system 77A and is reflected by the partial reflection surface 78b of the reflection member 78. Reflected by the surface 78c. The first detection light DL1 reflected by the reflection surface 78c passes outside the edge portion of the wafer W, and passes through the first objective lens system 77A, the half prism 76, and the second objective lens system 77B, and the image sensor 79. An image of the edge portion in the test area FVB of the wafer W is formed on the light receiving surface.

  On the other hand, the second detection light DL2 branched by the half prism 76 is reflected by the mirrors M2 and M3, the opening 72Aa of the suction portion 72A, and the reflection surface 78a of the reflection member 78, and passes through the transmission surface 78d of the partial reflection surface 78b. Then, the light enters the test region (part of the test region FVB) including the mark 46 on the back surface Wb of the wafer W. The second detection light DL2 reflected by the test region including the mark 46 returns to the half prism 76 via the transmission surface 78d, the reflection surface 78a, the opening 72Aa, the mirror M3, and the mirror M2. Then, the second detection light DL2 returned to the half prism 76 passes through the second objective lens system 77B and is adjacent to the image of the edge portion of the wafer W on the light receiving surface of the image sensor 79. An image of the mark 46 is formed. The image sensor 79 captures the image of the edge portion and the image of the mark 46 as one image. A detection signal (here, an imaging signal) of the imaging element 79 is supplied to the calculation unit 55 in FIG.

  Note that detection light having a wide wavelength band may be employed as the second detection light DL2. Specifically, a light source for irradiating the second detection light DL2 for detecting the mark 46 on the wafer W, an optical system such as a mirror, and a light source for irradiating the first detection light DL1 for detecting the edge of the wafer W And an optical system such as a mirror may be provided, and at least the second detection light DL2 may be configured to be detection light having a wide wavelength band. Thereby, for example, even when a foreign matter or the like adheres to the mark 46 of the wafer W and is contaminated, the mark 46 can be detected. Further, when the mark 46 on the wafer W is contaminated with foreign matter or the like, for example, the mark 46 may be cleaned. Examples of the cleaning treatment include optical cleaning using ultraviolet light, chemical cleaning using a predetermined chemical, physical polishing using a grindstone, and the like.

Further, the edge detectors 53A and 53B in FIG. 5A have the same configuration as the optical system in which the third objective lens system 77C and the mirror M2 are removed from the first optical system 54A of the mark detector 52 in FIG. is there. The edge detection units 53A and 53B capture images of the edge portions of the wafer W in the corresponding test regions FVA2 and FVA1, and supply detection signals to the calculation unit 55.
Next, in the exposure apparatus EX of the present embodiment, a detection method for detecting position information and the like of the mark 46 on the back surface of the wafer W using the mark detection apparatus 8 and an example of an exposure method using this detection method are shown in FIG. This will be described with reference to a flowchart. The operation of this method is controlled by the main controller 20 and the conveyance control system 50. First, in step 102 in FIG. 7, the reticle R is loaded onto the reticle stage RST in FIG. 1, and the alignment of the reticle R is performed. Thereafter, the wafer W coated with the photoresist is transferred from the coater / developer (not shown) to the transfer arm 61 of the wafer transfer robot WLD, and the tip of the transfer arm 61 holding the wafer W is shown in FIG. As shown in FIG. 4, the wafer transfer device 66 moves below the plurality of suction cups 68 (step 104). 8B is a cross-sectional view taken along line BB in FIG. 8A, and FIG. 8A corresponds to a cross-sectional view taken along line AA in FIG.

  At this time, the second optical system 54 </ b> B of the mark detection unit 52 is retracted to the position B <b> 2 so as not to contact the transport arm 61, and the three suction units 72 </ b> A to 72 </ b> C attached to the main body 67 are representative. As shown by dotted line positions B4 and B5 in FIG. 8B, the wafer is retracted to a position where it does not collide with the wafer W moving in the Y direction. A gap is secured between the two arm portions 61a and 61b of the transfer arm 61 so that the suction portion 72A can pass therethrough. Thereafter, as shown by a solid line in FIG. 8B, the suction portions 72A to 72C are rotated to hold the wafer W at the front ends of the suction portions 72A to 72C, and the main body portion 67 of the wafer transfer device 66 is slightly moved. Then, the wafer W is transferred from the transfer arm 61 to the wafer transfer device 66 (step 106). Substantially in parallel with this operation, wafer stage WST moves to wafer loading position LP below wafer transfer device 66. Then, the transfer arm 61 moves in the −Y direction as indicated by an arrow B8.

  Thereafter, as shown in FIGS. 5A and 5B, the second optical system 54B of the mark detection unit 52 is positioned on the −Y direction side of the third optical system 54C (reflection member 78) in the suction unit 72A. The second detection light DL2 of the mark detection unit 52 is irradiated onto the test region including the mark 46 on the back surface of the wafer W via the mirrors M2 and M3 and the third optical system 54C, and the reflected light from the mark 46 An image of the mark 46 is formed on the light receiving surface of the image sensor 79 (see FIG. 6). At the same time, the first detection light DL1 from the first optical system 54A is irradiated to the test region including the edge portion of the wafer W in the vicinity of the mark 46, and in the vicinity of the image of the mark 46 on the light receiving surface of the image sensor 79. An image of the edge portion is formed, and a detection signal obtained by capturing the image of the mark 46 and the image of the edge portion with the image sensor 79 is supplied to the arithmetic unit 55. The calculation unit 55 processes the detection signal, and as an example, with reference to a predetermined pixel (or index mark) in the image sensor 79, the position of the image of the edge portion of the wafer W in the X and Y directions, the mark 46 The position of the center of the image in the X direction and the Y direction and the rotation angle of the image of the mark 46 are obtained (step 108). As the rotation angle of the image of the mark 46, for example, an inclination angle with respect to the Y axis of the stage coordinate system (X, Y, Z) is obtained. Thereafter, the second optical system 54B of the mark detection unit 52 is retracted to the position B2.

  Substantially in parallel with step 108, detection light is irradiated from the edge detectors 53A and 53B into the test areas FVA2 and FVA1 including the edge part of the wafer W, and images of two edge parts are taken. The detection signal obtained in this way is supplied to the calculation unit 55. The computing unit 55 obtains the positions in the X and Y directions of the corresponding two edge portions from the detection signal (step 110). Further, the calculation unit 55 determines the X and Y directions in the stage coordinate system at the center of the wafer W from the position of the image of the three edge portions of the wafer W and the rotation angle of the image of the mark 46 on the back surface of the wafer W. The rotation angle of the position and the mark 46 (and consequently the wafer W itself) with respect to an axis parallel to the Y axis of the stage coordinate system is calculated, and the calculation result is stored in the storage unit 56 and supplied to the main controller 20 (step 112). ).

  5B, as an example, the center pins CP1 to CP3 are lifted from the wafer holder 44 side, and the suction of the wafer W by the suction portions 72A to 72C is released, and the tips of the center pins CP1 to CP3 are released. The wafer W is transferred to the part, and the suction parts 72A to 72C are retracted to the outside. Further, the main body 67 and the center pins CP1 to CP3 of the wafer transfer device 66 are moved in the −Z direction in a state where the wafer W is held in a non-contact manner so as to have a downward convex shape by the plurality of suction cups 68 of the wafer transfer device 66. Lower. Then, the wafer W is further lowered, and when the central portion of the wafer W comes into contact with the surface of the wafer holder 44 of the wafer stage WST, vacuum suction on the wafer holder 44 side is started and the holding of the plurality of suction cups 68 is released. As a result, the entire back surface of the wafer W is placed on the wafer holder 44 and sucked (step 114). Thereafter, the main body 67 of the wafer transfer device 66 is raised.

  Then, as an example, main controller 20 uses stage drive system 18 to set wafer stage WST (or wafer holder 44) so that the rotation angle of mark 46 (wafer W) obtained in step 112 becomes a known target value. ) Is corrected, and wafer stage WST is moved in the X and Y directions so that the center position of wafer W obtained in step 112 is at the target position (step 116). As a result, the pre-alignment of the wafer W is performed. When the first layer of the wafer W is exposed by performing pre-alignment, the arrangement direction of the many shot areas SA of the wafer W is set in accordance with the direction defined by the mark 46 of the wafer W, for example. Is done. Further, when the second and subsequent layers of the wafer W are exposed, since pre-alignment has been performed, the wafer mark attached to the shot area SA to be detected on the surface of the wafer W is quickly moved to the alignment system AL. Thus, the final alignment (fine alignment) of the wafer W can be efficiently performed.

  Thereafter, in the process of driving wafer stage WST to move wafer W below projection optical system PL (exposure position), alignment of wafer W is performed using alignment system AL (step 118). Is used to drive the wafer W, and an image of the pattern of the reticle R is scanned and exposed on each shot area of the wafer W (step 120). Thereafter, wafer stage WST is moved to unloading position UP, for example, another wafer transfer device is lowered, and wafer W is transferred from wafer holder 44 to the wafer transfer device, thereby unloading wafer W (step 122). ). The unloaded wafer W is transferred to a coater / developer (not shown) and developed. When the next wafer is exposed (step 124), the operations of steps 104 to 122 are repeated.

  According to this exposure method, when there is no notch on the outer shape of the wafer W and the mark 46 is formed on the back surface of the wafer W, the mark detection device 8 causes the mark 46 and the three edge portions of the wafer W to be formed. By detecting the position information and obtaining the center position of the wafer W and the rotation angle of the mark 46 (wafer W) from the detection result, the wafer W can be pre-aligned. Therefore, when the second and subsequent layers of the wafer W are exposed, the final alignment of the wafer W can be performed efficiently, and each shot area of the wafer W can be formed with high overlay accuracy with the pattern image of the reticle R. Can be exposed.

  As shown in FIG. 4F, when a conventional wafer W1 having a diameter of 300 mm or the like and provided with a notch portion NT as a notch portion is used, for example, two test regions (fields of view) are used. The position of the edge portion of the wafer W1 is detected by the FVA1 and FVA2, the position and direction of the notch portion NT is detected in the test region FVA3, and the center and rotation angle of the wafer W1 are obtained from these detection results. On the other hand, as shown in FIG. 4G, when using a wafer W2 having a diameter of 300 mm or the like and provided with an orientation flat portion OF as a notch, for example, in two test regions FVA2 and FVA3 The position and angle of the orientation flat portion OF are detected, the position of the edge portion of the wafer W2 is detected in the test area FVA1, and the center and rotation angle of the wafer W2 are obtained from these detection results. Based on the centers and rotation angles of the wafers W1 and W2 thus obtained, the wafers W1 and W2 are pre-aligned.

On the other hand, when using a wafer W having no cutout in the outer shape and having the mark 46 formed on the back surface as in the present embodiment, the mark 46 on the back surface of the wafer is used by using the mark detection device 8. The wafer W can be pre-aligned by detecting the position information.
Further, according to the exposure apparatus of the present embodiment, the wafer W is placed in the downward convex shape in a substantially non-contact state using the wafer delivery device 66, and the wafer W is placed on the wafer holder 44 of the wafer stage WST. . For this reason, even if the wafer W is large like a 450 mm wafer, the wafer W can be held on the wafer holder 44 in a state where the flatness of the wafer W is maintained high. Accordingly, high throughput can be obtained using the large wafer W, and the exposure accuracy (resolution, etc.) can be kept high on the entire surface of the wafer W, and the pattern image of the reticle R can be exposed with high accuracy.

  As described above, the exposure apparatus EX of the present embodiment includes the mark detection apparatus 8 that detects position information (including angle information) of the mark 46 (first mark) formed on the back surface of the wafer W (substrate). Yes. The mark detection apparatus 8 includes a wafer stage WST (substrate stage) that holds the wafer W when the wafer W is irradiated with exposure illumination light IL (exposure light), and the wafer W placed on the wafer stage WST. Before the wafer transfer is performed, the wafer transfer device 66 (substrate holding unit) that temporarily holds the wafer W and the position information of the mark 46 on the back surface of the wafer W in the state where the wafer W is held by the wafer transfer device 66 are obtained. And a mark detection unit 52 for detection.

In the mark detection method for detecting the position information of the mark 46 on the back surface of the wafer W according to the present embodiment, the wafer W is temporarily held by the wafer transfer device 66 before the wafer W is placed on the wafer stage WST. And step 108 for detecting the position information of the mark 46 in a state where the wafer W is held by the wafer transfer device 66.
According to the present embodiment, the position information of the mark 46 on the back surface of the wafer W is detected while the wafer W is held by the wafer delivery device 66. That is, since the mark 46 is detected during the transfer until the wafer W is placed on the wafer stage WST, the wafer W is large like a 450 mm wafer and the mark 46 is formed on the back surface. However, the position information of the mark 46 can be detected efficiently.

  The exposure apparatus EX of the present embodiment is an exposure apparatus that illuminates the pattern of the reticle R with the illumination light IL for exposure and exposes the wafer W through the pattern with the illumination light IL. And a main controller 20 (control unit) that corrects the position and rotation angle of the center of the wafer W based on the position information of the mark 46 on the back surface of the wafer W detected by the mark detection device 8. . In the exposure method using the exposure apparatus EX, the step 108 of detecting the position information of the mark 46 formed on the back surface of the wafer W using the mark detection method of the present embodiment and the wafer W are placed on the wafer stage WST. Step 114, and Step 116 for correcting the position and rotation angle of the center of the wafer W based on the position information detected by the mark detection method.

  According to the exposure apparatus or the exposure method of this embodiment, high throughput can be obtained by using a large wafer W. Further, even if the mark 46 is formed on the back surface of the wafer W, the position information of the mark 46 can be detected efficiently, and pre-alignment is performed by correcting the position and rotation angle of the wafer W using this detection result. Since this is performed, the final alignment of the subsequent wafer W can be efficiently performed, and higher throughput can be obtained.

In the above embodiment, the following modifications are possible.
First, in the above-described embodiment, the position and rotation angle of the center of the wafer W are corrected in step 116. However, at least one of the position and rotation angle may be corrected.
In FIG. 8, for example, the conveyance arm 61 is configured to pass between the mark detection unit 52 and the edge detection unit 53 </ b> A so that the second optical system 54 </ b> B of the mark detection unit 52 does not interfere with the movement of the conveyance arm 61. Also good. Accordingly, the position of the second optical system 54B of the mark detection unit 52 can be fixed to the position B without being retracted regardless of the position of the transport arm 61.

Further, in the above-described embodiment, the direction of one suction part 72A with respect to the center of the main body part 67 of the wafer transfer device 66 is the same as the direction of the mark detection part 52, and the first detection part 52 of the mark detection part 52 is connected to the suction part 72A. Since the three optical systems 54C (reflection members 78) are arranged, the configuration of the wafer transfer device 66 and the mark detection unit 52 can be simplified as a whole.
On the other hand, as shown in another arrangement example in FIG. 9A, the installation position of the suction units 72A to 72C of the wafer transfer device 66 and the installation position of the mark detection unit 52 may be changed. In FIG. 9A and later-described FIGS. 9B and 9C, portions corresponding to FIG. 5A are denoted by the same or similar reference numerals, and detailed description thereof is omitted.

  In the outer peripheral portion of the main body portion 67 of the wafer delivery device 66 shown in FIG. 9A, the connecting member 71D is displaced in the direction (-X direction in FIG. 9A) that is substantially 30 degrees counterclockwise with respect to the connecting member 71C. Is supported, and a rotating member 72D having substantially the same L shape as the suction portion 72A and not provided with a suction mechanism is supported so as to be rotatable by the motor 71Dm with respect to the connecting member 71D. The mark detection unit 52 includes a first optical system 54A provided in the vicinity of the connecting member 71D, a second optical system 54B provided movably at the end, and a reflecting member fixed to the rotating member 72D. 78 (third optical system 54C). In this case, a mark 46 (see FIG. 5B) is formed in the test region FVB (the back surface of the end portion in the −X direction of the wafer W) facing the reflecting member 78 on the back surface of the wafer W. An image of the mark 46 and an edge portion in the vicinity thereof is picked up using the mark detection unit 52.

  Further, the edge detection units 53A and 53B are fixed to the side surface of the main body 67 in a direction different by about ± 120 degrees with respect to the mark detection unit 52, for example, and the installation positions of the edge detection units 53A and 53B are It is different from the installation position. Also in this arrangement example, images of two edge portions of the wafer W are taken by the edge detection portions 53A and 53B. The subsequent processing is the same as in the above embodiment.

  Further, as shown in still another arrangement example in FIG. 9B, the mark detection unit 52 may be arranged so as to be substantially adjacent to the adsorption unit 72A. In FIG. 9B, an adsorbing portion 72A and a rotating member 72D are attached to the side surface of the main body 67 via a connecting member 71E so as to be rotatable. The reflecting member 78 as the third optical system 54C of the mark detection unit 52 is fixed to the rotation member 72D, and the first optical system 54A and the second optical system 54B of the mark detection unit 52 are arranged in the same direction as the rotation member 72. Is provided. Further, the suction portion 72A and the rotating member 72D are simultaneously driven to rotate by a common motor 71Em. In this arrangement example, the mark 46 (in FIG. 5 (FIG. 5 (FIG. 5)) is located in the test area FVB facing the reflecting member 78 on the back surface of the wafer W (a direction rotated slightly clockwise from the −Y direction end of the wafer W). B) is formed, and the mark 46 and the image of the edge portion in the vicinity thereof are picked up using the mark detection unit 52. The other edge detection units 53A and 53B are provided in the same direction as the suction units 72B and 72C, respectively, when the center of the wafer W is used as a reference. Note that the edge detection units 53A and 53B may be disposed adjacent to the suction units 72B and 72C, respectively.

Further, in this arrangement example, as shown in FIG. 9C, the suction portion 72A and the rotation member 72D are attached to the main body portion 67 through mutually different connecting members 71A and 71D, and the suction portion 72A and the rotation member 72D are attached. You may rotationally drive by motor 71Am and 71Dm which are mutually different.
Next, in the above embodiment, in order to guide the detection light from the light source 73 to the back surface of the wafer W, the mark detection unit 52 having the second optical system 54B for bypassing the detection light is used. On the other hand, the detection light that has passed through the first objective lens system 77A may be guided to the back surface of the wafer W, as shown by the mark detection unit 52A of the first modified example of FIG. 10A, parts corresponding to those in FIG. 6 are denoted by the same or similar reference numerals, and detailed description thereof is omitted.

  In FIG. 10A, among the detection lights emitted from the light source 73, the first detection light DL1 used for detection of the edge portion of the wafer W is indicated by a dotted line and used for detection of the mark 46 on the back surface of the wafer W. The second detection light DL2 is indicated by a solid line. As an example, since the edge portion of the wafer W is in the center of the test region (field of view) and the mark 46 is in the peripheral portion of the test region, the first detection light DL1 is substantially on the optical axis in the illumination σ stop 75A. They are parallel and the second detection light DL2 is relatively inclined with respect to the optical axis. Further, the wafer W on which the mark 46 is formed on the back surface is held on the upper surface of the tip portion of the suction portion 72A (not shown in FIG. 10A) of the wafer transfer device 66 shown in FIG.

  Further, a partial reflection mirror 81 is disposed so as to be close to the mark 46 on the back surface of the wafer W, and a right-angle prism-shaped reflection member 82 is disposed on the bottom surface side of the partial reflection mirror 81. In this modification, as an example, the partial reflection mirror 81 is fixed to the suction portion 72A, and the reflection member 82 is a transfer arm of the wafer transfer robot WLD shown in FIG. 1 for transferring the wafer W to the bottom surface of the wafer transfer device 66. 61 is fixed.

  As shown in the partially enlarged view of FIG. 10B, in the partial reflection mirror 81, a portion facing the edge portion of the wafer W and a region in the vicinity thereof becomes a reflection surface 81b, and a portion (in contact with the reflection surface 81b in the Y direction). (Including a portion facing the mark 46) are the transmission surfaces 81a and 81c. FIG. 10C is a bottom view of the partial reflection mirror 81 in FIG. As shown in FIG. 10C, portions adjacent to the transmission surface 81c of the partial reflection mirror 81 in the X direction become reflection surfaces 81d and 81e, and line-shaped index marks 83A elongated in the Y direction in the reflection surfaces 81d and 81e. , 83B (second mark) are formed. As an example, the index marks 83A and 83B are regions (black portions) having a lower reflectance than the other regions of the reflecting surfaces 81d and 81e. However, the index marks 83A and 83B are regions having a higher reflectance than the other regions. Also good.

  In FIG. 10A, the detection lights DL1 and DL2 emitted from the light source 73 are incident on the first half prism 76A via the first lens system 74A and the second lens system 74B for illumination and the mirror M1. The detection lights DL1 and DL2 branched by the half prism 76A are incident on the first objective lens system 77A. Then, the first detection light DL1 emitted from the first objective lens system 77A passes the outside of the edge portion of the wafer W and is reflected by the reflection surface 81b (see FIG. 10B) of the partial reflection mirror 81. . The first detection light DL1 reflected by the reflecting surface 81b passes outside the edge portion of the wafer W, and the first objective lens system 77A, the half prism 76A, the second objective lens system 77B, and the second half prism 76B. Then, an image of the edge portion of the wafer W is formed on the light receiving surface of the first image sensor 79A.

  On the other hand, the second detection light DL2 emitted from the first objective lens system 77A passes through the transmission surface 81a (see FIG. 10C) of the partial reflection mirror 81, the reflection member 82, and the transmission surface 81c of the partial reflection mirror 81. Then, the light enters the test region including the mark 46 on the back surface of the wafer W. Further, part of the second detection light DL2 reflected by the reflecting member 82 illuminates two index marks 83A and 83B provided so as to sandwich the transmission surface 81c of FIG. The second detection light DL2 including the light beam reflected by the test region including the mark 46 and passing through the transmission surface 81c of the partial reflection mirror 81 and the light beam reflected by the region including the index marks 83A and 83B is reflected by the reflecting member 82. , And the first objective lens system 77A through the transmission surface 81a of the partial reflection mirror 81. The second detection light DL2 returned to the first objective lens system 77A passes through the half prism 76A, the second objective lens system 77B, the second half prism 76B, and the glass plate 80 for correcting the optical path length. The image of the mark 46 on the wafer W and the images of the index marks 83A and 83B are formed on the light receiving surface of the image sensor 79B.

  As described above, the mark detection unit 52A receives the partial reflection mirror 81, the reflection member 82, the edge portions of the wafer W and the objective lens systems 77A and 77B that form the image of the mark 46, the image of the edge portion, and the image of the mark 46, respectively. The image sensors 79A and 79B to be imaged, and an optical path length correcting glass plate 80 for conjugating the formation surface of the mark 46 and the light receiving surface of the image sensor 79B are provided. In this modified example, the surface of the wafer W and the first imaging element are related to the first imaging optical system including the objective lens systems 77A and 77B in the mark detection unit 52A while the wafer W is held by the suction unit 72A and the like. The light receiving surface of 79A is optically conjugate. Further, regarding the second imaging optical system including the objective lens systems 77A and 77B and the optical path length correcting glass plate 80, the back surface of the wafer W (the surface on which the mark 46 is formed) and the light receiving surface of the second image sensor 79B. Is optically conjugate. The surface of the partial reflection mirror 81 on which the index marks 83A and 83B are formed is substantially within the depth of focus with respect to the back surface of the wafer W.

  Therefore, an image of the edge portion of the wafer W is formed with high contrast at the center of the light receiving surface of the first image sensor 79A, and the mark 46 and the index marks 83A, 83B are formed at the periphery of the light receiving surface of the second image sensor 79B. The 83B image is formed with high contrast. The image of the mark 46 is formed in a defocused state around the light receiving surface of the image sensor 79A, and the image of the edge portion of the wafer W is formed in a defocused state at the center of the light receiving surface of the image sensor 79B. However, these defocused images are not used.

  The first image sensor 79A supplies the detection signal of the image of the edge portion of the wafer W to the calculation unit 55 of FIG. 3, and the second image sensor 79B calculates the detection signal of the image of the mark 46 and the index marks 83A and 83B. To the unit 55. The arithmetic unit 55 processes the detection signals (here, the imaging signals) of the image sensors 79A and 79B to obtain the positional information of the image of the mark 46 on the edge portion of the wafer W and the back surface of the wafer W. The position information of the image of the mark 46 includes an inclination angle in the arrangement direction of the image of the mark 46 with respect to the longitudinal direction of the image of the index marks 83A and 83B. Further, the angle formed by the longitudinal direction of the index marks 83A and 83B and the axis parallel to the Y axis of the stage coordinate system (X, Y, Z) is known. For this reason, the wafer W can be pre-aligned similarly to the above-described embodiment by using the mark 46 of the wafer W obtained by using the mark detection unit 52A and the position information of the edge portion.

Since the mark detection unit 52A of this modification includes the partial reflection mirror 81 and the reflection member 82, the first objective lens system 77A can be used in common with respect to the detection lights DL1 and DL2. Can be simplified.
In this modification, both the partial reflection mirror 81 and the reflection member 82 may be fixed to the suction portion 72A, or both the partial reflection mirror 81 and the reflection member 82 may be fixed to the transport arm 61.

  Next, a second modification will be described with reference to FIGS. 11 (A) and 11 (B). In the first modification, the image of the edge portion of the wafer W and the image of the mark 46 are picked up by different image pickup elements 79A and 79B. In the second modification, the edge portion and the mark of the wafer W are marked. 46 images are captured by a common image sensor. Note that in FIG. 11A, portions corresponding to those in FIG. 10A are denoted by the same or similar reference numerals, and detailed description thereof is omitted.

  FIG. 11A shows a mark detector 52B of the second modification. In FIG. 11A, the first detection light DL1 reflected by the reflection surface 81b of the partial reflection mirror 81 passes outside the edge portion of the wafer W, and the first objective lens system 77A, the half prism 76A, and the first The image of the edge portion of the wafer W is formed at the center of the light receiving surface of the image sensor 79A via the two objective lens system 77B. In addition, an optical path length correcting glass plate 80A for conjugating the formation surface of the mark 46 of the wafer W and the light receiving surface of the image sensor 79A is disposed in front of the peripheral region of the light receiving surface of the image sensor 79A. Yes. As shown in an enlarged view in FIG. 11B, the optical path length correcting glass plate 80A is disposed in the optical path of the second detection light DL2 for detecting the mark 46 on the back surface of the wafer W.

  In FIG. 11A, a light beam that has been reflected by the test region including the mark 46 on the wafer W and passed through the transmission surface 81c of the partial reflection mirror 81 (see FIG. 10C), and the partial reflection mirror 81 are provided. The second detection light DL2 including the light beam reflected in the region including the index marks 83A and 83B (see FIG. 10C) is reflected through the reflection member 82 and the transmission surface 81a of the partial reflection mirror 81 to the first objective. Returned to the lens system 77A. The second detection light DL2 returned to the first objective lens system 77A passes through the half prism 76A, the second objective lens system 77B, and the optical path length correction glass plate 80A to the periphery of the light receiving surface of the image sensor 79A. Then, an image of the mark 46 on the wafer W and an image of the index marks 83A and 83B are formed. By processing the detection signal of the image sensor 79A, the position information of the image of the mark 46 on the edge portion of the wafer W and the back surface of the wafer W can be obtained efficiently.

In the mark detection unit 52B of this modification, the glass plate 80A that corrects the optical path length of the second detection light DL2 is disposed in front of the light receiving surface of the image sensor 79A, so that the edge of the wafer W is simultaneously performed by the common image sensor 79A. The image of the part and the image of the mark 46 on the back surface of the wafer W are taken. For this reason, the configuration of the mark detection unit 52B is further simplified.
Next, a third modification will be described with reference to FIGS. In the mark detection units 52 </ b> A and 52 </ b> B of the above modification, a partial reflection mirror 81 and a reflection member 82 are provided on the back side of the wafer W. In the third modification, the optical member on the back surface side of the wafer W is combined into one. 12A to 12C, the portions corresponding to those in FIGS. 11A, 10B, and 10C are denoted by the same or similar reference numerals, and detailed description thereof is omitted.

  FIG. 12A shows a mark detection unit 52C of a third modification. In FIG. 12 (A), it faces the mark 46 on the back surface of the wafer W held by the suction portions 72A to 72C (not shown in FIG. 12 (A)) of the wafer transfer device 66 of FIG. 5 (A). A right-angle prism-shaped optical member 82A is disposed. As an example, the optical member 82A is fixed to the suction portion 72A. The optical member 82A has an incident surface parallel to the back surface of the wafer W and two reflecting surfaces that intersect the incident surface at 45 degrees and are orthogonal to each other.

  As shown in the partially enlarged view of FIG. 12B, on the incident surface of the optical member 82A, the portion facing the edge portion of the wafer W and the region in the vicinity thereof becomes the reflecting surface 82Ab, and is in contact with the reflecting surface 82Ab in the Y direction. Portions (including a portion facing the mark 46) are transmission surfaces 82Aa and 82Ac (see FIG. 12C). FIG. 12C is a plan view of the optical member 82A in FIG. 12B and a plan view of an optical member 82B that can be used in place of the optical member 82A. As shown in FIG. 12C, the portions adjacent to the transmission surface 82Ac of the incident surface of the optical member 82A in the X direction become the reflection surfaces 82Ad, 82Ae, and the line-shaped index elongated in the Y direction in the reflection surfaces 82Ad, 82Ae. Marks 83A and 83B are formed. As an example, the index marks 83A and 83B are regions (black portions) having a lower reflectance than the other regions of the reflecting surfaces 82Ad and 82Ae, but the index marks 83A and 83B are regions having a higher reflectance than the other regions. Also good.

As shown by the optical member 82B, the width of the reflective surface 82Ad and the width of the region 82Af where the transmission surface 82Ac and the like are formed may be the same. Further, in the optical member 82B, the transmission surface on the −Y direction side of the reflection surface 82Ab is not shown. Other configurations are the same as those of the mark detection unit 52B of the second modified example of FIG.
In FIG. 12A, the first detection light DL1 emitted from the first objective lens system 77A is incident on the reflecting surface 82Ab (see FIG. 12B) of the optical member 82A. The first detection light DL1 reflected by the reflection surface 82Ab passes outside the edge portion of the wafer W, and passes through the first objective lens system 77A, the half prism 76A, and the second objective lens system 77B. An image of the edge portion of the wafer W is formed at the center of the light receiving surface of 79A.

  On the other hand, the second detection light DL2 emitted from the first objective lens system 77A includes a transmission surface 82Aa (see FIG. 12C) of the optical member 82A, two orthogonal reflection surfaces of the optical member 82A, and the optical member 82A. Is incident on the test region including the mark 46 on the back surface of the wafer W through the transmission surface 82Ac. Further, a part of the second detection light DL2 reflected by the two orthogonal reflecting surfaces of the optical member 82A has two index marks 83A and 83B provided so as to sandwich the transmitting surface 82Ac of FIG. Illuminate. The second detection light DL2 including the light beam reflected by the test region including the mark 46 and passing through the transmission surface 82Ac of the optical member 82A and the light beam reflected by the region including the index marks 83A and 83B is transmitted from the optical member 82A. The light is returned to the first objective lens system 77A via two orthogonal reflecting surfaces and the transmitting surface 82Aa of the optical member 82A. The second detection light DL2 returned to the first objective lens system 77A passes through the half prism 76A, the second objective lens system 77B, and the glass plate 80A for optical path length correction, and the periphery of the light receiving surface of the image sensor 79A. Then, an image of the mark 46 on the wafer W and an image of the index marks 83A and 83B are formed. By processing the detection signal of the image sensor 79A, the position information of the image of the mark 46 on the edge portion of the wafer W and the back surface of the wafer W can be obtained efficiently.

The mark detection unit 52C according to this modification simultaneously captures an image of the edge portion of the wafer W and an image of the mark 46 on the back surface of the wafer W by using a common image sensor 79A, and an optical member 82A is provided on the back surface side of the wafer W. Since only the arrangement is required, the configuration of the mark detection unit 52C is further simplified.
In the above embodiment, the wafer W is supported by the center pins CP <b> 1 to CP <b> 3 when the wafer W is moved up and down by the wafer transfer device 66. However, when the wafer W can be moved up and down stably by the wafer transfer device 66, the center pins CP1 to CP3 may be omitted.

[Second Embodiment]
A second embodiment will be described with reference to FIGS. 13 (A) and 13 (B). The basic configuration of the exposure apparatus of the present embodiment is substantially the same as that of the exposure apparatus EX of FIG. 1, but the configuration of the mark detection apparatus and the configuration of a part of the position measurement mechanism of wafer stage WST are different. 13A and 13B, parts corresponding to those in FIGS. 5A, 5B, and 11A are denoted by the same or similar reference numerals, and detailed description thereof is omitted. .

  FIGS. 13A and 13B show the mechanical part of the mark detection apparatus 8A according to this embodiment. The mark detection device 8A includes a wafer stage WST, a wafer transfer device 66 that temporarily holds the wafer W, a mark detection unit 52D that detects a mark 46 on the back surface of the wafer W, and edge portions at two locations on the wafer W. It has two edge detection parts 53A and 53B (53B is not shown) to detect. In FIG. 13A, the wafer W is held by suction portions 72A, 72B, 72C (72C not shown) of the wafer transfer device 66, and a mark 46 is formed on the back surface of the wafer W at a position close to the suction portion 72A. Is formed. FIG. 13A shows a state in which wafer stage WST on base board WB is moving in the −Y direction toward loading position LP below main body 67 of wafer transfer device 66. An opening 30a is formed in the bottom surface of the stage main body 30 of the wafer stage WST of the exposure apparatus of the present embodiment so as to penetrate in the Y direction, and the diffraction gratings 12A to 12D in FIG. A similar two-dimensional diffraction grating 12E is fixed.

  Further, independent of the frame member FR1 that supports the wafer transfer device 66, another frame member FR2 is stably supported on the floor surface via a vibration isolator (not shown). An L-shaped branch frame FR3 is fixed to the bottom surface of the frame member FR2. Similar to the detection head 14 in FIG. 2, the measurement beam is irradiated to the diffraction grating 12E on the end of the elongated flat plate rod portion FR3a parallel to the Y direction of the branch frame FR3 on the + Y direction side, and the diffraction grating 12E (and thus A detection head 14A for measuring relative displacement in the X and Y directions with respect to wafer stage WST) is fixed. That is, when wafer stage WST is moved in the −Y direction, rod portion FR3a of branch frame FR3 is inserted into opening portion 30a of stage body 30, and is provided on stage body 30 by detection head 14A provided on rod portion FR3a. The diffraction grating 12E can be detected. As described above, the exposure apparatus of this embodiment includes an additional encoder including the diffraction grating 12E and the detection head 14A in addition to the encoder 6 of FIG. With this additional encoder, the position of wafer stage WST in the X and Y directions can be measured in the vicinity of loading position LP.

  Further, the mark detection unit 52D of the present embodiment includes a first optical system 54D provided on the upper surface of the frame member FR2, and a bottom surface of the frame member FR2 with the opening FR2a of the frame member FR2 sandwiched from the first optical system 54D. And a third optical system 54F provided on the branch frame FR3. In the first optical system 54D, the detection light DL emitted from the light source 73 enters the half prism 76A via the illumination lens systems 74A and 74B and the mirror M1, and is detected by the half prism 76A. Passes through the aperture FR2a and enters the third optical system 54F via the first objective lens system 77A of the second optical system 54E and the mirror M4.

  In the third optical system 54F, the detection light DL incident from the mirror M4 passes through the mirror M5, the first lens system 77D of the relay optical system, the mirror M6, the second lens system 77E of the relay optical system, and the mirror M7. The light enters the test region including the mark 46 on the back surface of the wafer W held by the wafer transfer device 66. It is also possible to include the edge portion of the wafer W in this test region. In the present embodiment, the relative positions of the wafer transfer device 66 and the optical systems 54D to 54F (including the mirror M7) of the mark detection unit 52D are fixed, and the mirror M7 is in the Y direction of the rod portion FR3a of the branch frame FR3. It is fixed to the upper surface of almost the center.

  The detection light DL reflected by the test area on the back surface of the wafer W is passed through the mirror M7, the lens system 77E, the mirror M6, the lens system 77D, the mirrors M5 and M4, and the first objective lens system 77A. It is returned to the 54D half prism 76A. Then, the detection light DL returned to the half prism 76A forms an image of the mark 46 on the wafer W on the light receiving surface of the image sensor 79A via the second objective lens system 77B.

  In the present embodiment, the back surface of the wafer W is related to the imaging optical system including the objective lens systems 77A and 77B and the relay optical system including the lens systems 77D and 77E while the wafer W is held by the wafer transfer device 66. And the light receiving surface of the image sensor 79A are conjugate to the optical system, and the image of the mark 46 on the back surface of the wafer W is formed with high contrast on the light receiving surface of the image sensor 79A. When the edge portion of the wafer W is included in the test region, an image of the edge portion is formed along with the image of the mark 46 on the light receiving surface of the image sensor 79A. The image sensor 79A captures an image of the mark 46 (or the edge portion and the mark 46), and supplies a detection signal to the calculation unit 55 in FIG. Further, the edge detection units 53A and 53B (53B is not shown) capture images of two edge portions of the wafer W, and supply detection signals to the calculation unit 55. The calculation unit 55 processes these detection signals to determine the center position and rotation angle of the wafer W.

Thereafter, as shown in FIG. 13B, wafer stage WST is moved below wafer transfer device 66 (loading position LP), and wafer W is transferred from wafer transfer device 66 to wafer holder 44 of wafer stage WST. The wafer W is pre-aligned by correcting the position and rotation angle of the wafer W.
According to this embodiment, since the mark detection unit 52D is provided in the frame member FR2 (branch frame FR3), the suction unit 72A of the wafer transfer device 66 and the like are not provided with an optical system, and the wafer W can be stably formed. The position information of the mark 46 on the back surface can be detected efficiently.

In the above embodiment, the following modifications are possible.
In the above embodiment, the mark 46 on the back surface of the wafer W is detected while the wafer W is held by the wafer transfer device 66. On the other hand, as shown by the mark detection device 8B of the modified example of FIG. 14, the mark 46 on the back surface of the wafer W is marked with the wafer W held by the transfer arm 61 of the wafer transfer robot WLD of FIG. It may be detected. In FIG. 14, parts corresponding to those in FIGS. 5A, 5B, and 13A are denoted by the same or similar reference numerals, and detailed description thereof is omitted.

  FIG. 14 shows a main part of the mark detection device 8B of this modification. The mark detection device 8B includes a wafer stage WST, a wafer transfer robot WLD (substrate holding device) having a transfer arm 61 that temporarily holds the wafer W, and a mark detection unit 52E that detects a mark 46 on the back surface of the wafer W. And two edge detectors 53A1 and 53B1 that detect edge portions at two locations on the wafer W. The configuration of the edge detectors 53A1 and 53B1 is the same as that of the edge detectors 53A and 53B in FIG. 5A, but the edge detectors 53A1 and 53B1 of this modification are fixed to the frame member FR2A. FIG. 14 shows a state where wafer stage WST on base plate WB of the exposure apparatus is moving in the −Y direction toward loading position LP below transfer arm 61.

  In this modified example, a plurality of bar-shaped members (center pins) that can be vacuum-sucked so as to be movable in the Z direction are arranged in wafer holder 44 of wafer stage WST, and transfer arm 61 is connected to wafer holder 44 via these bar-shaped members. The wafer W is configured to be delivered. Therefore, in this modification, the wafer transfer device 66 of FIG. 5A is not necessarily required. In addition, an opening 30a is formed in the bottom surface of stage main body 30 of wafer stage WST so as to penetrate in the Y direction, and a two-dimensional diffraction grating 12E is fixed to the upper surface of opening 30a.

  Further, the frame member FR2A is stably supported on the floor surface via a vibration isolator (not shown). An L-shaped branch frame FR3A is fixed to the bottom surface of the frame member FR2A, and the transfer arm 61 and the like pass through a notch FR3Ab provided in the branch frame FR3A. The detection head 14A is fixed to the end of the elongated flat plate rod portion FR3Aa parallel to the Y direction of the branch frame FR3A on the + Y direction side, and the position of the wafer stage WST can be measured by the diffraction grating 12E and the detection head 14A.

  The mark detection unit 52E of this modification includes a first optical system 54G provided on the frame member FR2A and a second optical system 54H provided on the rod portion FR3Aa of the branch frame FR3A. In the second optical system 54H, the detection light DL emitted from the light source 73A enters the half prism 76B via the illumination lens system 74A, and the first detection light DL1 branched in the + Z direction by the half prism 76B is generated. Then, the light passes through the side surface of the edge portion of the wafer W and enters the first optical system 54G. In the first optical system 54G, the incident first detection light DL1 is received by the first imaging element 79A (for example, a CCD or a CMOS image sensor) via the objective lens systems 77A and 77B (first imaging optical system). An image of the edge portion of the wafer W is formed on the surface.

  On the other hand, the second detection light DL2 branched in the + Y direction by the half prism 76B enters the half prism 76C, and the second detection light DL2 branched in the + Z direction by the half prism 76C passes the mark 46 on the back surface of the wafer W. Illuminate the area to be examined. The second detection light DL2 reflected by the test region passes through the half prism 76C, passes through an opening (not shown) provided in the rod portion FR3Aa, and is reflected by the mirror M8 on the bottom surface side of the rod portion FR3Aa. The The reflected second detection light DL2 passes through the objective lens systems 77D and 77E (second imaging optical system) to the light receiving surface of the second imaging element 79B (for example, a CCD or CMOS image sensor) and the back surface of the wafer W. An image of the mark 46 is formed. The imaging elements 79A and 79B respectively capture the edge portion of the wafer W and the image of the mark 46, and supply a detection signal to the calculation unit 55 in FIG. Further, the edge detection units 53A1 and 53B1 capture images of two edge portions of the wafer W, and supply detection signals to the calculation unit 55. The calculation unit 55 processes these detection signals to determine the center position and rotation angle of the wafer W.

Thereafter, wafer stage WST is moved below transfer arm 61 (loading position LP), wafer W is transferred from transfer arm 61 to wafer holder 44 of wafer stage WST, and then the position and rotation angle of wafer W are corrected. Thus, pre-alignment of the wafer W is performed.
According to this modification, since the mark detection unit 52E is provided on the frame member FR2A (branch frame FR3A), the position of the mark 46 on the back surface of the wafer W can be stably provided without providing the transfer arm 61 with an optical system. Information can be detected efficiently.

  In each of the above embodiments, the imaging type edge detection units 53A and 53B are used to detect the edge portion of the wafer W. As another configuration, for example, a parallel light beam is irradiated so as to pass through the edge portion of the wafer W, and the light passing through the edge portion is detected by a photoelectric detector such as a photomultiplier or a photodiode via a condensing optical system. The position of the edge portion may be detected from the received light amount (detection signal).

  Further, in each of the above-described embodiments, in order to detect the position of the mark 46 on the back surface of the wafer W, the mark detection units 52 to 52D of the imaging method are used. As another configuration, for example, a detection unit that detects position information of the mark 46 by irradiating the mark 46 with a coherent light beam and detecting diffracted light generated from the mark 46 may be used. As another configuration, for example, a detection unit that detects position information of the mark 46 may be configured by using a laser displacement meter that can detect a step on the back surface of the wafer W due to the mark 46.

  Further, when an electronic device (or microdevice) such as a semiconductor device is manufactured using the exposure apparatus EX or the exposure method of each of the above embodiments, the electronic device has functions and performances of the electronic device as shown in FIG. Step 221 for performing design, Step 222 for manufacturing a reticle (mask) based on this design step, Step 223 for manufacturing a substrate (wafer) as a base material of the device and applying a resist, and the exposure apparatus of the above-described embodiment Substrate processing step 224 including a step of exposing a reticle pattern to the substrate (photosensitive substrate) by (exposure method), a step of developing the exposed substrate, a heating (curing) and etching step of the developed substrate, and a device assembly step ( (Including processing processes such as dicing, bonding, and packaging) 5, and an inspection step 226, and the like.

  In other words, in this device manufacturing method, the pattern of the photosensitive layer is formed on the substrate using the exposure apparatus EX or the exposure method of the above embodiment, and the substrate on which the pattern is formed is processed (development, etc.). And doing. At this time, according to the exposure apparatus EX or the exposure method of the above embodiment, even if the substrate is large and a mark is formed on the back surface, the mark on the substrate is efficiently detected, and the alignment of the substrate is efficiently performed. Therefore, an electronic device can be manufactured with high accuracy with extremely high throughput (productivity).

The present invention can be applied to a step-and-repeat type projection exposure apparatus (stepper or the like) in addition to the above-described scanning exposure type projection exposure apparatus (scanner). Furthermore, the present invention can be similarly applied to a dry exposure type exposure apparatus other than an immersion type exposure apparatus.
In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an image sensor (CCD or the like), a micromachine, a thin film magnetic head, and a DNA chip. Furthermore, the present invention can also be applied to an exposure apparatus when manufacturing a mask (photomask, reticle, etc.) on which a mask pattern of various devices is formed using a photolithography process.

  In addition, this invention is not limited to the above-mentioned embodiment, Of course, a various structure can be taken in the range which does not deviate from the summary of this invention.

  EX ... Exposure apparatus, R ... Reticle, W ... Wafer, WST ... Wafer stage, WLD ... Wafer transfer robot, 8, 8A ... Mark detection device, 44 ... Wafer holder, 46 ... Mark on wafer back surface, 52 ... Mark detection section, 53A , 53B ... Edge detection unit, 55 ... Calculation unit, 66 ... Wafer transfer device, 67 ... Main unit, 68 ... Suction cup, 72A to 72C ... Adsorption unit

Claims (26)

A mark detection device for detecting a first mark formed on the back surface of a substrate,
A substrate stage for holding the substrate when the substrate is irradiated with exposure light;
A substrate holding unit for temporarily holding the substrate before the substrate is placed on the substrate stage;
A detection unit that detects position information of the first mark in a state where the substrate is held by the substrate holding unit;
A mark detection apparatus comprising: The substrate holder is
A main body supported to be movable in the normal direction of the substrate;
A plurality of spacing control units that are supported by the main body in a state of being capable of facing the surface of the substrate and capable of controlling the spacing with the surface of the substrate, respectively.
A front end portion capable of supporting a part of the back surface of the substrate; and a support portion provided on the main body portion so that the front end portion can be inserted into and removed from the back surface side of the substrate.
The detector is
A transflective member having a reflective surface and a transmissive surface provided on the front end of the support portion so as to face the back surface of the substrate;
A first imaging unit that illuminates an edge portion of the substrate from the back surface side of the substrate through the reflective surface of the semi-transmissive member and captures an image of the edge portion;
An image of the first mark is received by illuminating the first mark on the back surface of the substrate through the transmission surface of the semi-transmissive member and receiving reflected light reflected by the back surface and returned through the transmission surface. The mark detection apparatus according to claim 1, further comprising: a second imaging unit that images The detector is
An optical path bending member that is provided at the distal end portion of the support portion so as to overlap the semi-transmissive member and folds an optical path of light passing through the transmission surface of the semi-transmissive member;
The second imaging unit illuminates the first mark on the back surface of the substrate through the transmission surface of the optical path bending member and the semi-transmissive member, and reflects the transmission surface and the optical path bending member reflected on the back surface. The mark detection apparatus according to claim 2, wherein the mark detection apparatus receives reflected light returned through the first mark and picks up an image of the first mark. A reflection surface and a transmission surface are formed on one surface of the optical path bending member,
The mark detection apparatus according to claim 3, wherein the optical path bending member also serves as the semi-transmissive member. A substrate transfer unit that transfers the substrate to a holding position by the substrate holding unit;
The detector is
An optical path bending member that is provided at a position that can be positioned so as to overlap the semi-transmissive member of the substrate transport unit, and that bends an optical path of light that passes through the transmission surface of the semi-transmissive member;
The second imaging unit illuminates the first mark on the back surface of the substrate through the transmission surface of the optical path bending member and the semi-transmissive member, and reflects the transmission surface and the optical path bending member reflected on the back surface. The mark detection apparatus according to claim 2, wherein the mark detection apparatus receives reflected light returned through the first mark and picks up an image of the first mark. The semi-transmissive member has a reflective portion provided in the vicinity of the transmissive surface, and a second mark provided in the reflective portion,
The second imaging unit illuminates the first mark on the back surface of the substrate through the transmissive surface of the semi-transmissive member and illuminates the second mark in the reflective portion of the semi-transmissive member, Receiving reflected light that is reflected by and reflected back through the transmitting surface, picks up an image of the first mark, and receives reflected light returned through the reflecting portion of the semi-transmissive member, The mark detection apparatus according to claim 2, wherein an image of the second mark is picked up.   The said 1st imaging part and the said 2nd imaging part share the image pick-up element which can image the image of the edge part of the said board | substrate, and the image of the said 1st mark of the back surface of the said board | substrate within the same visual field. The mark detection device according to any one of the above. The substrate holder is
A main body supported to be movable in the normal direction of the substrate;
A plurality of spacing control units that are supported by the main body in a state of being capable of facing the surface of the substrate and capable of controlling the spacing with the surface of the substrate, respectively.
A front end portion capable of supporting a part of the back surface of the substrate; and a support portion provided on the main body portion so that the front end portion can be inserted into and removed from the back surface side of the substrate.
A frame member having a front end portion disposed at a position facing the back surface of the substrate in a state where the substrate is held by the substrate holding portion and supported independently from the main body portion of the substrate holding portion. With
The detector is
A reflective member provided at the tip of the frame member;
Illuminating the first mark on the back surface of the substrate from the back surface side of the substrate through the reflecting member, receiving reflected light reflected by the back surface and returned through the reflecting member, and The mark detection apparatus according to claim 1, further comprising: an imaging unit that captures an image.   The said imaging part receives the reflected light reflected on the said back surface of the said board | substrate, and returns via the said reflection member, The image of the said 1st mark and the said edge part of the said board | substrate is imaged. Mark detection device.   The said 1st mark formed in the back surface of the said board | substrate is a mark detection apparatus as described in any one of Claims 1-9 which has several recessed part arrange | positioned along the straight line in the said back surface.   The mark detection apparatus according to claim 1, wherein the substrate has a disk shape with a diameter of 300 to 450 mm. In an exposure apparatus that illuminates a pattern with exposure light and exposes the substrate through the pattern and the projection optical system with the exposure light,
The mark detection device according to any one of claims 1 to 11,
A controller that corrects at least one of the position and the rotation angle of the substrate based on the position information of the first mark formed on the back surface of the substrate detected by the mark detection device;
An exposure apparatus comprising: A mark detection method for detecting a first mark formed on a back surface of a substrate,
Temporarily holding the substrate by a substrate holding unit before the substrate is placed on a substrate stage that holds the substrate when exposure light is irradiated;
Detecting position information of the first mark in a state where the substrate is held by the substrate holding unit;
Mark detection method including Disposing a transflective member having a reflective surface and a transmissive surface so as to face the back surface of the substrate,
Detecting the position information of the first mark
Illuminating an edge portion of the substrate from the back surface side of the substrate through the reflective surface of the semi-transmissive member, and capturing an image of the edge portion;
An image of the first mark is received by illuminating the first mark on the back surface of the substrate through the transmission surface of the semi-transmissive member and receiving reflected light reflected by the back surface and returned through the transmission surface. The mark detection method according to claim 13, further comprising: Disposing an optical path bending member that bends an optical path of light passing through the transmission surface of the semi-transmissive member so as to face the back surface of the substrate and to overlap the semi-transmissive member;
Taking an image of the first mark illuminates the first mark on the back surface of the substrate through the transmission surface of the optical path bending member and the semi-transmissive member, and is reflected by the back surface and the transmission surface and The mark detection method according to claim 14, further comprising: receiving reflected light returned through the optical path bending member and capturing an image of the first mark. A reflection surface and a transmission surface are formed on one surface of the optical path bending member,
The mark detection method according to claim 15, wherein the optical path bending member also serves as the semi-transmissive member. Including transporting the substrate to a holding position by the substrate holder, and disposing an optical path bending member that bends an optical path of light passing through the transmission surface of the semi-transmissive member so as to overlap the semi-transmissive member,
Taking an image of the first mark illuminates the first mark on the back surface of the substrate through the transmission surface of the optical path bending member and the semi-transmissive member, and is reflected by the back surface and the transmission surface and The mark detection method according to claim 14, wherein reflected light returned through the optical path bending member is received to capture an image of the first mark. The semi-transmissive member has a reflective portion provided in the vicinity of the transmissive surface, and a second mark provided in the reflective portion,
Taking an image of the first mark
The first mark on the back surface of the substrate is illuminated through the transmissive surface of the semi-transmissive member and the second mark in the reflective portion of the semi-transmissive member is illuminated, and is reflected on the back surface to reflect the transmissive surface. And receiving the reflected light returned through the reflecting portion of the translucent member and receiving the reflected light returned through the reflecting portion of the semi-transmissive member to capture the image of the second mark. The mark detection method according to any one of claims 14 to 17, further comprising: Taking an image of the edge portion and taking an image of the first mark are:
19. The mark detection method according to claim 14, comprising capturing an image of an edge portion of the substrate and an image of the first mark on the back surface of the substrate with the same image sensor. Holding the substrate by the substrate holding portion so that the back surface of the substrate faces the front end portion of the frame member supported independently of the substrate holding portion,
Detecting the position information of the first mark
Reflected light that illuminates the first mark on the back surface of the substrate from the back surface side of the substrate through a reflective member provided at the tip of the frame member and is reflected by the back surface and returned through the reflective member. The mark detection method according to claim 13, further comprising: picking up an image of the first mark. In parallel with detecting the position information of the first mark,
21. The mark detection according to claim 20, further comprising: receiving reflected light that is reflected from the back surface of the substrate and returned through the reflecting member to capture an image of the first mark and the edge portion of the substrate. Method.   The said 1st mark formed in the back surface of the said board | substrate is a mark detection method as described in any one of Claims 13-21 which has a some recessed part arrange | positioned along the straight line in the said back surface.   The mark detection method according to any one of claims 13 to 22, wherein the substrate has a disk shape with a diameter of 300 to 450 mm. In an exposure method of illuminating a pattern with exposure light and exposing the substrate through the pattern with the exposure light,
Using the mark detection method according to any one of claims 13 to 23 to detect positional information of the first mark formed on the back surface of the substrate;
Placing the substrate on a substrate stage;
Correcting at least one of the position and rotation angle of the substrate based on the position information detected by the mark detection method;
An exposure method comprising: Forming a pattern of a photosensitive layer on a substrate using the exposure apparatus according to claim 12;
Processing the substrate on which the pattern is formed;
A device manufacturing method including: Forming a pattern of a photosensitive layer on a substrate using the exposure method according to claim 24;
Processing the substrate on which the pattern is formed;
A device manufacturing method including:

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