JP2015070014A - Substrate holding method and device, and exposure method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize local lowering of the flatness even of a large substrate, when the substrate is mounted at a target position.SOLUTION: A wafer holding device 8 includes a wafer holder 54 on which a wafer W is mounted, a lift 47 provided to elevate and lower for the wafer holder 54 and suction holding the wafer W, a drive unit 56 for elevating and lowering the lift 47. The lift 47 has a body 46c in which a negative pressure space NP generating a negative pressure for suction is formed, and three branches branched from the body 46c. The branches have three suction holes 45Aa-45Ca communicating with the negative pressure space NP, respectively.

Description

  The present invention relates to a substrate holding technique for holding a substrate, an exposure technique using the substrate holding technique, and a device manufacturing technique using the exposure technique.

  In an exposure apparatus such as a so-called stepper or scanning stepper used in a photolithography process for manufacturing an electronic device (microdevice) such as a semiconductor element, for example, a disk-shaped semiconductor wafer (hereinafter, referred to as a substrate to be exposed) In order to hold the wafer), three lift pins (center pins) that can be moved up and down for wafer transfer are arranged at almost equal angular intervals between a large number of small pin-shaped protrusions. A so-called pin chuck type wafer holder is used. In addition, in order to increase the throughput (productivity) when manufacturing electronic devices, SEMI (Semiconductor Equipment and Materials International) standards (SEMI standards) of wafer diameters are almost 125 mm, 150 mm, 200 mm, and 300 mm every few years. It increases at a rate of 1.25 to 1.5 times.

  A lift pin provided in a conventional wafer holder is a rod-like member having a substantially the same size at the tip portion contacting the wafer and the lower portion thereof, and an exhaust hole for vacuum suction is formed at the center portion. (For example, refer to Patent Document 1).

US Pat. No. 6,590,633

  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. When the wafer is further increased in size in this way, the conventional method of simply lowering the three rod-shaped lift pins that hold the wafer and transferring the wafer to the mounting surface of the wafer holder (the upper surfaces of many protrusions) Further, the suction force to the wafer is not sufficient, and there is a possibility that local deformation (distortion) occurs in the wafer at the lift pin portion. When the wafer is locally deformed in this way, when the wafer is placed on the placement surface, a gap (space) is partially formed between the wafer and the placement surface due to residual distortion of the wafer or the like. May occur. If a partial gap is generated between the wafer and the mounting surface in this way, the flatness of the exposed area of the wafer may be reduced, and the exposure accuracy (resolution, etc.) may be partially reduced.

  In view of such circumstances, the aspect of the present invention suppresses a decrease in local flatness of the substrate even when the substrate to be held is placed at a target position even if the substrate is large. The purpose is to be able to.

  According to the first aspect of the present invention, there is provided a substrate holding device for holding a substrate, the substrate holding portion on which the substrate is placed, and the substrate holding portion which is provided so as to be movable up and down. A support member that sucks and supports the back surface, and a drive device that raises and lowers the support member, and the support member includes a main body portion in which a negative pressure space in which a negative pressure for suction is generated is formed And a plurality of branch portions branched from the main body portion, each of the branch portions has a plurality of support portions that support the back surface of the substrate, and at least one of the plurality of support portions, There is provided a substrate holding device provided with a suction port communicating with the negative pressure space.

According to the second aspect, in the exposure apparatus that illuminates the pattern with the exposure light and exposes the substrate through the pattern with the exposure light, the substrate holding according to the aspect of the present invention for holding the substrate to be exposed An exposure apparatus including an apparatus and a stage that moves while holding the substrate holding apparatus is provided.
According to the third aspect, there is provided a substrate holding method using the substrate holding apparatus according to the aspect of the present invention, wherein the end of the support member is raised with respect to the substrate holding part, and the substrate is formed at the end. Sucking and supporting the back surface of the substrate, lowering the support member relative to the substrate holding device, and from the end of the support member to the surface of the substrate holding portion on which the substrate is placed A substrate holding method comprising: delivering the substrate.

According to the fourth aspect, in an exposure method in which a pattern is illuminated with exposure light and the substrate is exposed through the pattern with the exposure light, the substrate is held using the substrate holding method of the aspect of the present invention. And moving the substrate to an exposure position.
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 back surface of the substrate is supported by the plurality of support portions respectively provided at the plurality of branch portions of the support member, when the substrate is supported, local deformation of the substrate is caused. It is suppressed. For this reason, when the substrate to be held is placed at a target position, even if the substrate is large, a decrease in local flatness of the substrate can be suppressed.

It is a figure which shows schematic structure of the exposure apparatus which concerns on 1st Embodiment. It is a top view which shows the wafer stage of FIG. 2 is a block diagram showing a control system and the like of the exposure apparatus of FIG. (A) is a top view which shows the wafer holding apparatus of FIG. 1, (B) is a figure which shows the cross section and control part which looked at FIG. 4 (A) from the front. FIG. 4A is a perspective view showing a lift part of the wafer holding device in FIG. 4B, FIG. 4B is a perspective view showing a lift part of a modified example, and FIG. It is an expanded sectional view. It is a flowchart which shows an example of the exposure method containing the holding method of a wafer. (A) is sectional drawing which shows the state which delivered the wafer to the support pin, (B) is sectional drawing which shows the state which the center part of the wafer contacted the wafer holder. (A) is a perspective view which shows the raising / lowering part of a modification, (B) is a perspective view which shows the raising / lowering part of another modification. (A) is a plan view showing a cross-sectional shape of a plurality of support pins of a modified example, (B) is a plan view showing a cross-sectional shape of a plurality of support pins of another modified example, (C) is a further modified example of It is a top view which shows the cross-sectional shape of a some support pin. (A) is a top view which shows arrangement | positioning of the some support pin of a modification, (B) is a top view which shows arrangement | positioning of the some support pin of another modification. (A) is a top view which shows the wafer holding apparatus which concerns on 2nd Embodiment, (B) is a figure which shows the cross section which looked at FIG. 11 (A) from the front, and a control part. 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 7B. FIG. 1 shows a schematic configuration of an exposure apparatus EX provided with a wafer holding device (substrate holding device) according to this embodiment. As an example, the exposure apparatus EX is a scanning exposure type projection exposure apparatus including 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, and the −Z direction is the direction of the vertical line.

  The exposure apparatus EX includes 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. It includes a reticle stage RST that holds a reticle R (mask) that is 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 holding apparatus 8 that holds the wafer W (see FIG. 3), A wafer stage WST that moves while supporting a mechanical portion of the wafer holding device 8, a control system, and the like (see FIG. 3) are provided.

  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 the reticle interferometer 24 is sent to the main controller 20 comprising a computer shown 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 conjugate to the illumination area IAR) of one shot area of W. As an example, the wafer W includes a wafer (photosensitive material) coated with a photoresist (photosensitive material) with a thickness of about several tens to 200 nm on a large disk-shaped substrate having a diameter of 300 mm or 450 mm made of a semiconductor such as silicon. The thickness of the substrate having a diameter of 300 mm is, for example, 775 μm, and the thickness of the substrate having a diameter of 450 mm is currently assumed to be, for example, about 900 to 1100 μm (for example, about 925 μm).

  Further, in the exposure apparatus EX, in order to perform exposure using the liquid immersion method, the lower end of the lens barrel 40 that holds the tip lens 91 that is an optical element on the most image plane side (wafer W side) constituting the projection optical system PL. A nozzle unit 32 constituting a part of the local liquid immersion device 38 is provided so as to surround the periphery of the part. 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.

  As an example, as shown in FIG. 2, the alignment system AL is arranged in an X-direction (non-scanning direction) in a region having a length of 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. A wafer transfer robot WLD (see FIG. 1) for loading the wafer W is installed near the loading position LP, and a wafer transfer robot (not shown) for loading the wafer W is installed near the unloading position UP. Yes.

  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. Efficiently measure the Z position distribution on the surface of the wafer W by the multi-point AF system 90 and position measurement of a plurality of wafer marks (marks attached to each shot area of the wafer W) by the alignment systems ALa to ALe. It can be carried out. The measurement result of the multipoint AF system 90 and the measurement result of 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 body 30 driven in the X direction and Y direction, wafer table WTB as a Z stage mounted on stage body 30, and wafer for stage body 30. And a Z stage driving unit that relatively finely drives the Z position of the table WTB and the tilt angles in the θx direction and the θy direction. Inside the opening at the center of wafer table WTB is provided a wafer holder 54 that holds wafer W on a mounting surface that is substantially parallel to the XY plane by vacuum suction or the like, and includes wafer holder 54 and a mechanical portion of wafer holding device 8. 50 (see FIG. 3) is configured. The wafer stage main body 30 itself may be configured to be driven in six degrees of freedom (X, Y, Z, θx, θy, θz directions) by a planar motor or the like.

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 member 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 liquid immersion device 38, the plate body 28 has a circular shape as shown in the plan view of the wafer stage WST in FIG. It has a plate part (liquid repellent plate) 28b that surrounds the opening 28a and has a liquid-repellent treatment on a surface having a rectangular outer shape (outline), and a peripheral part 28e that surrounds the plate part 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 is 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 the relative position in the direction and the Z direction (three-dimensional) are fixed (see FIG. 2). 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. 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 80A and 80B. In the measurement value switching units 80A and 80B, information on the relative position supplied from the measurement calculation unit 42 corresponding to the detection head 14 facing the diffraction gratings 12A to 12D 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 80A and 80B, 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 wafer holding device 8 of the present embodiment will be described in detail. Wafer holding device 8 has a mechanism unit 50 including a wafer holder 54 incorporated in wafer stage WST, and a wafer holder control system 51 that controls the operation of mechanism unit 50 under the control of main controller 20.
4A is a plan view showing the wafer holding device 8 of FIG. 1, FIG. 4B is a longitudinal sectional view (cross-sectional view seen from the front) in the substantially center portion in the X direction of FIG. 4A, and a wafer holder. A control system 51 is shown. In FIG. 4B, for example, a low expansion coefficient metal Z stage 53 is provided via, for example, voice coil motor type driving units 63A, 63B, 63C that are displaceable in three Z directions on the upper surface of the stage body 30. Is held. The Z stage 53 corresponds to the wafer table WTB in FIG.

The Z stage 53 is a rectangular box-like member with an open top, and a bottom surface 54 e of the wafer holder 54 is fixed to an inner surface 53 a substantially parallel to the XY plane in the central recess of the Z stage 53, and the upper surface of the wafer holder 54 is A wafer W is held on the substrate. The diffraction gratings 12 </ b> A to 12 </ b> D are fixed to the upper surface of the side wall portion of the Z stage 53 via the plate body 28.
The bottom of the wafer holder 54 has a circular flat plate shape, and a ring-shaped closed side wall 54c is integrally formed on the upper surface of the bottom. The size of the side wall part 54c is slightly smaller than the edge part of the peripheral edge of the wafer W to be held. The peripheral edge of the wafer W may be supported by the side wall 54c. If the diameter of the wafer W is 300 mm or 450 mm, the outer diameter of the side wall portion 54c is formed slightly smaller than 300 mm or 450 mm, respectively. For example, the wafer holder 54 is formed of a material having a very small coefficient of thermal expansion. Such materials include ultra-low expansion glass (eg Corning's ULE (trade name)), ultra-low expansion glass ceramics (eg Schott's Zerodur (trade name)), or silicon carbide (SiC). ) Etc. can be used.

  Further, as shown in FIG. 4A, in the region surrounded by the side wall portion 54c on the bottom of the wafer holder 54, as an example, a large number of positions are formed at each lattice point of a two-dimensional lattice having an equilateral triangle as a basic shape. A pin-shaped protrusion 54b is integrally formed. The interval between the plurality of adjacent protrusions 54b is, for example, several mm (for example, about 3 mm), and the upper surfaces of the numerous protrusions 54b and the side wall parts 54c are extremely high planes so that they are on the same plane (substantially parallel to the XY plane). Finished in degrees. An imaginary plane including the upper surfaces of the multiple protrusions 54b and the side wall portions 54c becomes the mounting surface 54a of the wafer W. The wafer W to be exposed is placed on the placement surface 54a so that gaps are not generated as much as possible between the back surface of the wafer W and the upper surfaces of the numerous protrusions 54b and the side wall portions 54Ac. The wafer holder 54 can be manufactured by, for example, polishing the surface of the protrusion 54b and the like after being integrally formed. For convenience of explanation, the wafer W is indicated by a two-dot chain line in FIG.

  Further, a vacuum suction hole (hereinafter referred to as a suction hole) 55 is formed almost at the center of the region surrounded by the side wall portion 54c on the upper surface of the wafer holder 54, and a first circumference C1 surrounding the suction hole 55 at the center. A plurality of suction holes 55 are formed at substantially equal angular intervals along the second circumference C2 and the third circumference C3. These suction holes 55 are formed in a region between a large number of protrusions 54b. It is not always necessary to provide the suction hole 55 at or near the center, and further, the location and number of suction holes 55 can be arbitrarily set as will be described later.

  In the present embodiment, in order to suck the back surface of the wafer W more uniformly and stably onto the mounting surface 54a, at least six suction holes 55 are formed as an example at substantially equal angular intervals along the circumferences C1 to C3. It is preferable to provide it. However, the number of suction holes 55 arranged along the respective circumferences C1 to C3 is arbitrary, and the number of suction holes 55 arranged along the respective circumferences C1 to C3 may be different from each other. The plurality of suction holes 55 may be provided along a plurality of straight lines set at substantially equal angular intervals around the center of the wafer holder 54, for example. As shown in FIG. 4B, the plurality of suction holes 55 are respectively flexible exhaust pipes 61B via an exhaust path a1 in the bottom of the wafer holder 54 and an exhaust path a2 in the Z stage 53. Communicating with The exhaust pipe 61B is connected to a vacuum pump 62 outside the wafer stage WST via an exhaust path 30a of the stage body 30 and a flexible exhaust pipe 61A.

  The exhaust pipe 61B has a valve (hereinafter referred to as an adsorption valve) V11 for starting vacuum adsorption and a valve (hereinafter referred to as an adsorption release valve) V2 for releasing the vacuum adsorption by communicating the inside of the exhaust pipe 61B with the atmosphere. Is installed. The opening and closing of the valves V1, V2 is controlled by the wafer holder control system 51. A suction mechanism for the wafer holder 54, which includes a bottom portion provided with a plurality of suction holes 55 of the wafer holder 54, exhaust pipes 61A and 61B, and a vacuum pump 62, and holds the wafer W on the mounting surface 54a of the wafer holder 54 by vacuum suction. (Second adsorption part) is configured. In addition, it is good also as a structure which can control mutually independently the timing of the vacuum suction with respect to the wafer W through the center suction hole and the suction hole 55 provided along several circumference C1-C3, and the cancellation | release of vacuum suction. Further, the suction to the wafer W through the suction hole 55 may be started after the wafer W is placed on the wafer holder 54, or may be started before the wafer W is placed. Further, the suction pressure on the wafer W may be varied. For example, the suction pressure may be gradually increased as the wafer W approaches the wafer holder 54.

Further, in the region surrounded by the side wall 54c of the wafer holder 54, for example, three positions CT1, 1 set at substantially equal angular intervals along the circumference CT between the first circumference C1 and the second circumference C2. CT2 and CT3 are set. A rod-like member elongated in the Z direction (hereinafter referred to as a support pin) that can be moved up and down in the Z direction while sucking and supporting the back surface of the wafer W so as to surround these three positions CT1, CT2, and CT3. 45A, 45B, 45C are arranged. The support pins 45 </ b> A to 45 </ b> C are inserted through through holes provided in the wafer holder 54 and the Z stage 53, respectively. The front ends (also referred to as “end portions” or “support portions”) of the support pins 45 </ b> A to 45 </ b> C are finished with high flatness so as to be the same XY plane. Note that the tips of the support pins 45A to 45C do not necessarily have to be on the same plane as when the support pins 45A to 45C can move up and down independently of each other. As an example, the three support pins 45A to 45C arranged so as to surround the positions CT1 to CT3 are arranged so as to be located at the vertices of a substantially equilateral triangle having the vertices toward the center of the wafer holder 54. As an example, the outer shapes of the three support pins 45A to 45C are the same. Moreover, as an example, the outer shape of the three support pins 45A to 45C is a small cylindrical shape having a diameter of about 3 to 5 mm. Further, in the center of the three support pins 45A, 45B, 45C, vacuum suction holes (hereinafter referred to as suction holes) 45Aa, 45Ba, 45Ca (hereinafter referred to as suction holes) for sucking (sucking) the wafer W with negative pressure, respectively. 5A) is formed. As an example, the suction holes 45Aa to 45Ca are circular with a diameter of about 1 to 2 mm. The negative pressures generated by the support pins 45A to 45C may be the same value, or the negative pressure of at least one of the support pins 45A to 45C may be different from the negative pressure of other support pins. . Further, the negative pressure generated by the support pins 45A to 45C can be set to an arbitrary value as long as the wafer W is not peeled off.
Further, the value of the negative pressure generated by the support pins 45 </ b> A to 45 </ b> C may be varied, for example, between holding the wafer W and placing it on the wafer holder 54. Further, it is not necessary that all of the support pins 45A to 45C are provided with the above-described vacuum suction holes, and at least one of the support pins 45A to 45C may be provided with a vacuum suction hole. .

  Furthermore, as an example, at least one protrusion 54b of the wafer holder 54 is disposed in a region surrounded by the three support pins 45A to 45C. With this arrangement, when the tip portions of the support pins 45A to 45C are retracted downward (−Z direction) from the mounting surface 54a, the protrusions 54b in the region surrounded by the support pins 45A to 45C are formed on the wafer W. Since the back surface is supported, the flatness of the wafer W can be maintained high. The support pins 45A to 45C can also be referred to as lift pins. Further, when the support pins 45A to 45C are arranged at positions close to the center of the wafer holder 54, the support pins 45A to 45C can be referred to as center pins, respectively.

  In order to stably support the wafer W, it is preferable that at least three sets of support pins 45A to 45C (around three positions CT1 to CT3) are arranged. FIG. 4B shows support pins 45A, 45C and 45A, 45B in the vicinity of positions CT1 and CT3 in FIG. 4A. The three support pins 45A to 45C may be arranged in the vicinity of the corresponding positions CT1 to CT3, for example, along a straight line extending in the radial direction from the center of the wafer holder 54.

  When the diameter of the wafer W is 450 mm, a plurality of sets of support pins 45A to 45C (position CT1) are used to stably support the wafer W with a plurality of sets (three sets in FIG. 4A) of support pins 45A to 45C. It is preferable that the diameter of the circumference CT in which .about.CT3) is arranged is, for example, 180 to 350 mm (about 2/5 to 7/9 of the diameter of the wafer W). When the diameter of the wafer W is 450 mm, the diameter of the circumference CT may be set to about 200 mm, for example. Further, the diameter of the circumference CT where the support pins 45A to 45C are arranged is such that when the wafer W is supported by a plurality of sets of support pins 45A to 45C, the amount of deflection of the wafer W is minimized, that is, the wafer W May be determined to be supported at a position corresponding to a so-called Bessel point. The diameter of the circumference CT indicating the position corresponding to the Bessel point when the diameter of the wafer W is 450 mm is about 280 to 310 mm.

  The lower ends of the support pins 45A to 45C arranged so as to surround the positions CT1 to CT3 are respectively connected to the upper connecting portions 44Aa of the lower end support portions 44A, 44B, and 44C arranged below the Z stage 53 (−Z direction). 44Ba and 44Ca (see FIG. 5A). As an example, the connecting portions 44Aa to 44Ca have a substantially circular (equilateral triangular shape or the like) flat plate shape. The lower end support portions 44A and 44C (the same applies to 44B) are respectively fixed to the tips of the upper column portions 46b (details will be described later) of the driven portion 46 by, for example, bolts B1 (see FIG. 4B).

  FIG. 5A is a perspective view showing a portion including the support pins 45A to 45C and the lower end support portions 44A to 44C of FIG. 5A, the lower end support portions 44A to 44C are fixed to a driven portion 46 that is driven in the Z direction by a drive portion (not shown). This driven portion 46 has a central rectangular flat plate-like main body portion 46c and three elongated branch portions branched from the main body portion 46c at substantially equal angular intervals (equal intervals of 120 ° in FIG. 5A). ing. This branch part has support | pillar part 46b1-46b3 (1st support | pillar), and the axially long shaft part 46a provided in the Z direction provided in the bottom face of the main-body part 46c. In order to avoid complication of the drawing, in FIG. 4B, the column portions 46b1 to 46b3 are collectively represented by the column portion 46b. The shaft portions 44Ab, 44Bb, 44Cb below the lower end support portions 44A, 44B, 44C are respectively attached to the tips of the three column portions 46b1, 46b2, 46b3 of the driven portion 46, for example, bolts B1 (see FIG. 4B). It is fixed by. Note that the lower end support portions 44A to 44C may be fixed to the tips of the three column portions 46b1 to 46b3 of the driven portion 46 by adhesion or welding, respectively. The first struts 46b1 to 46b3 do not necessarily have to be branched from the main body portion 46c at equal angular intervals. For example, the first struts 46b1 to 46b3 may have different intervals (unequal angular intervals) between adjacent first struts, or at least one part. May be branched so as to have the same interval.

  And three support pins 45A-45C (2nd support | pillar) are each connected with connection part 44Aa, 44Ca, 44Ba which is the upper part of lower end support part 44A, 44B, 44C. Note that these three support pins 45A to 45C are also included in the above-described branch portion. The wafer holder 54 includes three sets of support pins 45 </ b> A to 45 </ b> C, three lower end support portions 44 </ b> A to 44 </ b> C, and a driven portion 46, while supporting or holding the back surface of the wafer W by partial vacuum suction (suction). The raising / lowering part 47 (support member) which is a member which can be raised-lowered in the normal line direction (Z direction) of the mounting surface 54a of this is comprised. Further, the first branching portion 43A is constituted by the column portion 46b1, the lower end support portion 44A, and the support pins 45A to 45C, and the second branch portion 43B is formed from the column portion 46b2, the lower end support portion 44B, and the support pins 45A to 45C. The third branching portion 43A is constituted by the column portion 46b3, the lower end support portion 44C, and the support pins 45A to 45C.

  As an example, the support pins 45A to 45C and the lower end support portion 44A (or 44B, 44C) are integrally formed. The support pins 45A to 45C and the lower end support portion 44A are made of a material having a very low thermal expansion coefficient like the wafer holder 54, for example, silicon carbide (SiC), silicon carbide ceramics, ultra-low expansion glass, or ultra-low expansion glass. It is formed from materials such as ceramics. The support pins 45A to 45C and the lower end support portion 44A can be manufactured by, for example, integrally molding and then polishing the tips of the support pins 45A to 45C with high flatness. In addition, after manufacturing support pin 45A-45C and the lower end support part 44A separately, you may fix support pin 45A-45C to the lower end support part 44A by adhesion | attachment or welding.

  In the present embodiment, since the back surface of the wafer W is supported by the support pins 45A to 45C, the wafer W supported by the support pins 45A to 45C is not deformed such as local warping or bending. The surfaces of the tips of the support pins 45A to 45C (portions in contact with the wafer W) are preferably slippery. Therefore, as an example, the surface of the tip of the support pins 45A to 45C may be subjected to processing for reducing friction such as formation of a diamond-like carbon (DLC) film.

  In addition, as support pin 45A-45C, as shown by support pin 45A1 of FIG.5 (C), you may use the member with a large shape of a front-end | tip part. The support pin 45A1 has a cylindrical shaft portion 45A1a that is inserted through the wafer holder 54, and a cylindrical tip portion 45A1b that is integrally connected to the tip of the shaft portion 45A1a and has a larger cross-sectional shape than the shaft portion 45A1a. A suction hole 45A1c is provided at the center of the recess 45A1d surrounded by the outer periphery of the tip 45A1b. By using the support pins 45A1 having a large tip shape in this way, the wafer W may be supported more stably even if the wafer W is large.

The driven portion 46 is made of a material having a very low coefficient of thermal expansion like the wafer holder 54, such as silicon carbide (SiC), silicon carbide ceramics, ultra-low expansion glass, or ultra-low expansion glass ceramics. Can be formed from Furthermore, the driven part 46 can also be formed from a metal or alloy having a low coefficient of thermal expansion.
4B, the stage main body 30 is provided with a drive unit 56 for driving the shaft part 46a of the driven part 46 of the elevating part 47 in the Z direction. The drive unit 56 elevates and lowers the shaft portion 46a and consequently the elevating unit 47 in the Z direction by, for example, a voice coil motor method or a rack and pinion method. Further, a position sensor (not shown) such as an optical linear encoder for measuring the position of the shaft portion 46a in the Z direction is provided. The wafer holder control system 51 controls the position of the elevating unit 47 (three sets of support pins 45A to 45C) in the Z direction via the drive unit 56 based on the detection result of the position sensor.

  Further, when at least one tip of the support pins 45A to 45C comes into contact with the back surface of the wafer W while the support pins 45A to 45C are rising, the thrust of the drive unit 56 is increased, for example, the drive current is increased. Therefore, as an example, the wafer holder control system 51 monitors the drive current of the drive unit 56 and can recognize whether or not the support pins 45A to 45C are in contact with the wafer W from the change in the drive current. When the wafer W is placed on the placement surface 54a on the numerous protrusions 54b of the wafer holder 54 and the wafer W is exposed, the elevating part 47 is lowered to the lowest position (position in the -Z direction). In addition, the tips of the three support pins 45A to 45C of the elevating unit 47 are retracted to a position lower than the placement surface 54a. At the time of exposure of the wafer W, the heights of the tips of the support pins 45A to 45C are set to the same height as the mounting surface 54a, and the back surface of the wafer W is formed by the multiple protrusions 54b and the three sets of support pins 45A to 45C. May be supported.

  In FIG. 4B, the suction holes 45Aa to 45Ca of the three sets of support pins 45A to 45C (only some of them are shown in FIG. 4B) correspond to the driven parts 46, respectively. A sealed space that can be set to a negative pressure in the main body portion 46c of the driven portion 46 via the exhaust passage a3 in the supporting column portions 46b1 to 46b3 (represented by 46b in FIG. 4B). Hereinafter, it is referred to as negative pressure space.) It communicates with NP. The negative pressure space NP in the main body 46c communicates with the exhaust pipe 61C through the flexible exhaust pipe 60. The exhaust pipe 61C is connected to the vacuum pump 62 via the exhaust path 30a of the stage body 30 and the flexible exhaust pipe 61A. Also on the exhaust pipe 61C, an adsorption valve V3 for starting vacuum adsorption by the support pins 45A to 45C and an adsorption release valve V4 for releasing the vacuum adsorption are mounted. Wafer holder control system 51 controls the opening and closing of valves V3 and V4. A suction mechanism (first) that includes the exhaust pipes 60, 61A, 61C, valves V3, V4, and the vacuum pump 62, and holds the back surface of the wafer W by vacuum suction (suction) at the tips of the plurality of support pins 45A to 45C. (Adsorption part) is constituted.

Since the exhaust path a3 is provided in each of the column portions 46b1 to 46b3, the column portions 46b1 to 46b3 can be regarded as cylindrical (or cylindrical) members.
Further, the entire suction mechanism 52 is configured including the exhaust pipes 60, 61 </ b> A to 61 </ b> C, the valves V <b> 1 to V <b> 4, and the vacuum pump 62. A mechanism unit 50 (see FIG. 3) of the wafer holding device 8 is configured including the wafer holder 54, the elevating unit 47, the driving unit 56 of the elevating unit 47, and the suction mechanism 52. The second suction part that sucks the back surface of the wafer W with a negative pressure on the mounting surface 54a of the wafer holder 54 and the first suction part that sucks the back surface of the wafer W with a negative pressure on the tips of the support pins 45A to 45C, Each of them is a part of the entire suction mechanism 52. Note that a plurality of vacuum pumps may be prepared, and the first suction unit and the second suction unit may be provided with vacuum pumps independently.

  In the present embodiment, the plurality of suction holes 55 outside the center of the wafer holder 54 are provided at substantially the same angle in the circumferential direction. The centers (positions CT1 to CT3) of the three sets of support pins 45A to 45C are arranged between the plurality of suction holes 55 in the circumferential direction. With this arrangement, when the wafer W is transferred from the support pins 45A to 45C to the mounting surface 54a of the wafer holder 54, switching to the suction via the suction hole 55 of the wafer holder 54 can be performed smoothly. Distortion can be suppressed.

  Next, an example of a holding method for holding the wafer W using the wafer holding device 8 in the exposure apparatus EX of the present embodiment and an example of an exposure method using this holding method will be described with reference to the flowchart of FIG. The operation of this method is controlled by the main controller 20 and the wafer holder control system 51. First, in step 102 in FIG. 6, the reticle R is loaded onto the reticle stage RST in FIG. 1, and the alignment of the reticle R is performed. Thereafter, in a state where wafer W is not loaded, wafer stage WST moves to loading position LP in FIG. 2, and wafer transfer robot WLD (wafer loader system) in FIG. 1 performs unexposed wafer W coated with a photoresist. Is transferred onto wafer stage WST (step 104). At this time, the wafer W placed on the fork-type wafer arm WLDa (see FIG. 7A) at the tip of the wafer transfer robot WLD moves above the wafer holder 54 fixed to the wafer stage WST. At this stage, suction (including suction of the support pins 45A to 45C) by the suction mechanism 52 of the wafer holding device 8 is released, and the tips of the support pins 45A to 45C are positioned below the wafer W.

  Thereafter, as shown in FIG. 7A, the wafer holder control system 51 raises the elevating part 47 (support pins 45A to 45C) (moves in the + Z direction) while holding the suction holes of the three sets of support pins 45A to 45C. The vacuum suction operation via 45Aa to 45Ca is started (step 106). And after the front-end | tip of support pin 45A-45C contacts the back surface of the wafer W, the raising / lowering part 47 is further raised, Then, the raising / lowering part 47 is stopped (step 108). At this time, the wafer W is adsorbed to the tips of the support pins 45A to 45C, and the positional deviation between the wafer W and the support pins 45A to 45C does not occur. At this time, the wafer W is transferred from the wafer arm WLDa to the tips of the support pins 45A to 45C. In this state, the wafer arm WLDa is retracted in the −Y direction (step 110).

  Thereafter, with the wafer W being supported, the elevating unit 47 (support pins 45A to 45C) is lowered (step 112). Then, as shown in FIG. 7B, when the tips of the support pins 45A to 45C approach the placement surface 54a, the suction mechanism 52 starts vacuum suction via the suction holes 55 of the wafer holder 54, and the support pins When the tips of 45A to 45C reach the mounting surface 54a, the adsorption of the wafer W by the support pins 45A to 45C is released (step 114). The elevating unit 47 stops at a position where the tips of the support pins 45A to 45C are lower than the placement surface 54a. 4B, the back surface of the wafer W is placed on the placement surface 54a of the wafer holder 54, and the wafer W is transferred from the support pins 45A to 45C to the wafer holder 54 (step 116).

  At this time, in this embodiment, the back surface of the wafer W is supported by three sets of three support pins 45A to 45C arranged so as to surround the three positions CT1 to CT3 on the circumference CT with respect to the wafer holder 54. Thus, the support pins 45 </ b> A to 45 </ b> C are lowered to transfer the wafer W to the wafer holder 54. For this reason, even if the wafer W is a large substrate (450 mm wafer) such as a disk-shaped substrate having a diameter of 450 mm, for example, the local area of the wafer W is supported by the portions supported by the three sets of support pins 45A to 45C. This makes it difficult to deform. Therefore, when the wafer W is mounted on the mounting surface 54a of the wafer holder 54, the wafer W is less likely to be deformed, warped, or distorted, and the back surface of the wafer W and the mounting surface 54a (side wall portion 54c) are prevented. In addition, gaps (spaces) are less likely to be partially formed between the upper surface of the protrusions 54 b and the upper surface of the multiple protrusions 54 b, and the wafer W is held by the wafer holder 54 with high flatness. The support pins 45A to 45C at the respective locations may be raised or lowered in synchronization with the positions CT1 to CT3, or may be raised or lowered independently of each other.

  Furthermore, in the present embodiment, the back surface of the wafer W is sucked with negative pressure through the suction holes 45Aa to 45Ca of the three support pins 45A to 45C arranged so as to surround the three positions CT1 to CT3. The wafer W is lowered onto the mounting surface 54a. At this time, the wafer W tends to be placed on the placement surface 54a in a state of being convex toward the wafer holder 54 (hereinafter referred to as a downward convex shape). For this reason, when the wafer W is placed on the placement surface 54a and the wafer holder 54 starts to adsorb the wafer W, the residual distortion of the wafer W is further reduced, and the wafer W is held at a higher flatness. Can be retained. The support pins 45A to 45C at the positions CT1 to CT3 may be raised or lowered in synchronization with each other, or may be raised or lowered independently of each other.

  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, the wafer stage WST is moved to the unloading position UP, the suction of the wafer W via the wafer holder 54 by the suction mechanism 52 of the wafer holding device 8 is released, and the wafer is moved via the elevating unit 47 (support pins 45A to 45C). The wafer W is unloaded by raising W and delivering the wafer W to an unloading wafer transfer robot (not shown) (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.

  As described above, according to the exposure method of the present embodiment, the wafer W is sucked and supported by the three sets of the three support pins 45A to 45C. The wafer W can be stably supported without causing local deformation. For this reason, when the wafer W is transferred to the wafer holder 54, the flatness of the wafer W can be 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 wafer holding device 8 that holds the wafer W (substrate). The wafer holding device 8 includes a wafer holder 54 (substrate holding part) on which the wafer W is placed, and an elevating part that is provided so as to be movable up and down in the Z direction with respect to the wafer holder 54 and sucks and supports the back surface of the wafer W. 47 (supporting member) and a driving unit 56 (driving device) for moving the lifting unit 47 in the Z direction. The elevating part 47 includes a main body part 46c in which a negative pressure space NP in which a negative pressure for suction (vacuum suction) is generated is formed, and three branch parts 43A to 43C branched from the main body part 46c. Each of the branch portions 43A to 43C has three suction holes 45Aa to 45Ca (suction ports) that communicate with the negative pressure space NP.

  The wafer holding apparatus 8 holds the wafer W by raising the end of the elevating unit 47 (support member) (the tips of the support pins 45A to 45C) in the Z direction with respect to the wafer holder 54 (substrate holding unit). Step 106 for sucking and supporting the back surface of the wafer W by the suction holes 45Aa to 45Ca at the end, Step 112 for lowering the lifting unit 47 in the −Z direction with respect to the wafer holder 54, and an end of the lifting unit 47 A step 116 of delivering the wafer W from the (tips of the support pins 45A to 45C) to the mounting surface 54a on which the wafer W of the wafer holder 54 is mounted.

  According to the present embodiment, the back surface of the wafer W at the portion where the three suction holes 45Aa to 45Ca of the three branch portions 43A to 43C of the elevating portion 47 are provided (tip portions of the support pins 45A to 45C). Therefore, when the wafer W is supported by the elevating unit 47 (support member), local deformation of the wafer W is suppressed. For this reason, when the wafer W to be held is placed on the placement surface 54a (target position) of the wafer holder 54, even if the wafer W is large, such as a 450 mm wafer, a local plane of the wafer W is obtained. Degradation can be suppressed.

  Moreover, in this embodiment, the raising / lowering part 47 has the axial part 46a which receives the motive power of the drive part 56, three support | pillar parts 46b1-46b3 (1st support | pillar) branched from the main-body part 46c, and support | pillar part 46b1-46b3. Are provided with three support pins 45A to 45C (second support columns), and suction holes 45Aa to 45Ca are provided in these support pins 45A to 45C, and these three sets of support pins 45A to 45C are provided. The back surface of the wafer W is sucked and supported through the gap. For this reason, the local distortion of the wafer W can be further suppressed, and the wafer W can be stably supported.

  In the present embodiment, the back surface of the wafer W can be sucked (sucked) with a negative pressure through the suction holes 45Aa to 45Ca, so that the wafer W is received by the lift 47 (support pins 45A to 45C) from the wafer transfer robot WLD. While being transferred and further transferred to the wafer holder 54, the relative position between the wafer W and the wafer holder 54 does not change. For this reason, the subsequent alignment of the wafer W can be performed efficiently.

  The exposure apparatus EX of the present embodiment is an exposure apparatus that illuminates the pattern of the reticle R with exposure illumination light IL (exposure light) and exposes the wafer W with the illumination light IL through the pattern. A wafer holding device 8 for holding the wafer W to be exposed and a wafer stage WST that holds and moves the wafer holder 54 of the wafer holding device 8 are provided. The exposure method using the exposure apparatus EX includes steps 106 to 116 for holding the wafer W using the wafer holding device 8 and step 118 for moving the held wafer W to the exposure position.

  According to the exposure apparatus EX or the exposure method of the present embodiment, for example, high throughput can be obtained by increasing the size of the wafer W, and the wafer W can be stably moved when the wafer W is moved from the wafer transfer robot WLD to the wafer holder 54. When the wafer W is supported and placed on the wafer holder 54, the flatness of the wafer W can be maintained high. For this reason, high exposure accuracy can be obtained.

In the above embodiment, the following modifications are possible. In the following description of the modified examples, in FIGS. 5B and 8A to 10B, portions corresponding to FIGS. 4A, 4B, and 5A. Are denoted by the same or similar reference numerals, and detailed description thereof is omitted.
First, in the above-described embodiment, the suction holes 45Aa to 45Ca are provided in all of the plurality of support pins 45A to 45C of the wafer holding device 8. On the other hand, among the support pins 45A to 45C, it is sufficient that at least one support pin is provided, and it is not always necessary to provide suction holes in all the support pins 45A to 45C. At this time, the tip of the support pin not provided with the suction hole may be covered with the diamond-like carbon (DLC) film described above.

As an example, as shown by a lifting / lowering portion 47A of the modification of FIG. 5B, a plurality of (for example, three) branching portions 43A1, 43B1, and 43C1 are respectively provided on a plurality (for example, two) of support pins 45A and 45B. The suction holes 45Aa and 45Ba may be provided, and the support pins 45C may not be provided with the suction holes. Even in this case, the wafer W can be stably held at the tip of the elevating part 47A.
Further, in the above-described embodiment, as shown in FIGS. 4B and 5A, the support pins 45A to 45C of the elevating unit 47 of the wafer holding device 8 are supported through the lower end support units 44A to 44C. It is connected to the portions 46b1 to 46b3.

On the other hand, as shown by the lifting / lowering part 47B of another modified example of FIG. 8A, the tips of a plurality (here, three) of the column parts 46b1 to 46b3 branched from the main body part 46c of the driven part 46. In addition, the support pins 45A to 45C may be fixed by bolts (not shown) or adhesive. In this example, the branch portions 43A2, 43B2, and 43C2 are configured by the support pins 45A to 45C and the column portions 46b1, 46b2, and 46b3, respectively. And the some support | pillar part 46b1-46b3 has a structure which supports support pin 45A-45C (2nd support | pillar), respectively. For this reason, the structure of the raising / lowering part 47B may be simplified.
Note that the support pins 45A to 45C may be branched directly from the main body 46c without the support portions 46b1 to 46b3. In other words, the “branch portion” in the present embodiment includes support pins 45A to 45C branched from the main body portion 46c without the support portions 46b1 to 46b3.

  Further, as shown by a lifting / lowering portion 47C of the modified example of FIG. 8B, on the peripheral portion of the upper surface of the disk-shaped main body portion 46Ac (the shaft portion 46Aa is provided on the bottom surface) of the driven portion 46A. The support pillars 46Ab1 to 46Ab3 may be fixed, and the support pins 45A to 45C may be connected to the support pillars 46Ab1 to 46Ab3 via the lower end support parts 44A to 44C. In this modified example, branch portions 43A3, 43B3, and 43C3 are configured by the support pins 45A to 45C, the lower end support portions 44A to 44C, and the column portions 46b1, 46b2, and 46b3 extending in the Z direction, respectively. Also in this example, a plurality of sets of support pins 45A to 45C can be moved up and down in the Z direction.

  In the above-described embodiment, in the wafer holder 54, three sets of a plurality of supports arranged so as to surround the positions CT1 to CT3 (or in the vicinity of the positions CT1 to CT3) on the circumference CT in FIG. The shape and arrangement of the pins 45A to 45C are equal to each other. However, the shape and / or arrangement of the plurality of support pins may be different from each other. Further, the intervals between the three support pins 45A to 45C at the respective positions CT1 to CT3 can be arbitrarily set. For example, when the configuration shown in FIGS. 5 and 8 is used as a reference, the three support pins may be arranged so that the phases of the three support pins are shifted by an arbitrary angle between 0 ° and 180 °. FIGS. 9A to 10B referred to below are plan views showing the wafer holder 54, respectively, but the protrusion 54b, the side wall 54c, and the suction hole 55 of the wafer holder 54 are omitted. .

  For example, as shown in the modified example of FIG. 9A, regarding the three support pins 45A1, 45B1, and 45C1 of the wafer holding device disposed so as to surround the positions CT1 to CT3 in the wafer holder 54, for example, the support pins 45A1 are provided. The support pins 45B1 and 45C1 may be formed large and small. In this example, for example, a suction hole (not shown) may be formed in at least one of the large support pins 45B1 and 45C1.

  Further, as shown in the modified example of FIG. 9B, regarding the three support pins 45A1, 45B2, and 45C2 disposed so as to surround the positions CT1 to CT3 in the wafer holder 54, for example, the support pins 45A1 are formed in a columnar shape. The support pins 45B2 and 45C2 may be formed in a prismatic shape (for example, a quadrangular prism). Also in this example, for example, a suction hole (not shown) may be formed in at least one of the support pins 45B2 and 45C2.

  Further, as shown in the modification of FIG. 9C, regarding the three support pins 45A, 45B, and 45C disposed in the vicinity of the positions CT1 to CT3 in the wafer holder 54, for example, at the positions CT1 and CT2, the support pins 45A to 45A to 45C. 45C may be arrange | positioned in the position of each vertex of a triangle, and support pin 45A-45C may be arrange | positioned along the straight line which passes along position CT3 in position CT3. Further, for example, in the vicinity of the position CT3, instead of the columnar support pins 45A to 45C, as shown in the enlarged view D, the support pins 45A3.45B3.45C3 having an elliptical cross section are arranged along a straight line passing through the position CT3. May be arranged. Thus, the shapes of the support pins 45A to 45C may be different from each other, and the arrangement of the support pins 45A to 45C may be different between the positions CT1 to CT3.

  Further, as shown in the modification of FIG. 10A, for example, three supports are provided so as to surround, for example, five positions CT1 to CT5 set at substantially equal angular intervals along the same circumference in the wafer holder 54. The pins 45A1, 45B2, and 45C2 may be disposed. Thus, the place where the three support pins 45A to 45C are arranged is not limited to three places, and may be three or more places (for example, five places as in this example). Further, the interval / distance between the plurality of positions CT where the support pins 45A to 45C are arranged is arbitrary. For example, the three positions CT1 to CT3 may be arranged so as to be shifted by an arbitrary angle between 0 to 180 ° when the arrangement positions in FIGS. 5 and 8 are used as a reference. In this example, the support pins 45A1 are, for example, cylindrical, and the support pins 45B2, 45C2 are, for example, prismatic (eg, quadrangular), but support pins having the same shape are arranged instead of the support pins 45A1, 45B2, 45C2. Also good. Note that the plurality of (for example, three) support pins 45A to 45C are three or more arbitrary positions CT1 to CTn (n is 3) set at substantially equal angular intervals along the same circumference in the wafer holder 54. You may arrange | position so that the above integer) may be enclosed. The number of the positions CT1 to CTn may be a multiple of 3, for example (3, 6, or 9). Further, a plurality of support pins 45A to 45C are also arranged at the center portion of wafer holder 54 (in the vicinity of position CT0), and a plurality of support pins 45A to 45C at the center portion and a plurality around the circumference surrounding the center. The back surface of the wafer W may be supported by a set of support pins 45A to 45C.

  Further, the number of support pins 45A to 45C and the like disposed in the vicinity of each position CT0 to CTn may be two (for example, support pins 45A and 45B), or may be four or more. That is, the number of the support pins 45A and the like arranged in the vicinity of the positions CT0 to CTn may be at least two. Further, for example, two support pins 45A or the like may be disposed in the vicinity of the position CT1, and for example, three support pins 45A or the like may be disposed in the vicinity of the other position CT2.

Further, as shown in the modified example of FIG. 10B, a plurality (see FIG. 10) of at least three positions P1 to P5 (for example, five positions in FIG. 10B) arranged irregularly in the wafer holder 54, for example. (B) three) support pins 45A1, 45B2, 45C2 may be arranged.
In the above-described embodiment, when the wafer W is transferred from the support pins 45 </ b> A to 45 </ b> C to the mounting surface 54 a of the wafer holder 54, for example, vacuum suction is started in the order from the central opening 55 to the outer opening 55 of the wafer holder 54. May be. As a result, the wafer W is placed on the placement surface 54a so as to be convex toward the wafer holder 54, so that residual distortion is further reduced.

  In the above embodiment, the suction mechanism 52 holds the wafer W by vacuum suction on the wafer holder 54 via the suction hole 55, but the wafer W can also be held on the wafer holder 54 by electrostatic suction. . In the case of electrostatic attraction, it is possible to support the wafer W by this flat portion with the mounting surface of the wafer holder 54 as a flat portion without providing a large number of protrusions 54b on the upper surface of the wafer holder 54.

[Second Embodiment]
The second embodiment will be described with reference to FIGS. 11A and 11B. The basic configuration of the exposure apparatus of the present embodiment is the same as that of the exposure apparatus EX of FIG. 1, but the configuration of the lifting unit 47D of the wafer holding device is different from the lifting unit 47 of the above embodiment. 11A and 11B, portions corresponding to those in FIGS. 4A and 4B are denoted by the same or similar reference numerals, and detailed description thereof is omitted.

  FIG. 11A is a plan view showing a mechanism portion 50A (see FIG. 11B) of the wafer holding apparatus 8A according to this embodiment, and FIG. 11B is a substantially central portion in the X direction of FIG. 11A. The longitudinal cross-sectional view (cross-sectional view seen from the front) in FIG. 2 and the wafer holder control system 51 are shown. In FIG. 11B, a driven portion 46 is arranged on the upper surface of the stage main body 30 so as to be moved up and down in the Z direction by the driving portion 56. Further, the lower end support portions 74A, 74B, and 74C having the same shape are respectively attached to the tip portions of the three column portions 46b branched from the main body portion 46c including the negative pressure space NP of the driven portion 46 (see FIG. 11A). Is fixed by, for example, a bolt B1. Thus, in this embodiment, the support | pillar part 46b (1st support | pillar) and several lower end support part 74A-74C each connected to the front-end | tip of this support | pillar part 46b are disclosed as a branch part. For example, the lower end support portion 74A includes an elongated cylindrical shaft portion 74Ab inserted into a through hole provided in the wafer holder 54 and the Z stage 53, and a substantially triangular flat plate integrally provided at the upper end of the shaft portion 74Ab. Shaped connecting portion 74Aa. The region of the wafer holder 54 in which a large number of protrusions 54b are formed accommodates the connecting portions 74Aa and the like of the lower end support portions 74A to 74C around three positions set at substantially equal angular intervals along the circumference CT. A cutout portion (corner portion) 54f and the like are formed. For this reason, in a state where the wafer W is placed on the placement surface 54 a of the wafer holder 54, the connecting portions 74 </ b> Aa of the lower end support portions 74 </ b> A to 74 </ b> C are positioned between the placement surface 54 a and the bottom surface 54 e of the wafer holder 54. .

  Further, support pins 75A, 75B, and 75C (second shapes) in which the lengths in the Z direction of the support pins 45A to 45C in FIG. 4A are respectively shortened on the upper surfaces of the connecting portions 74Aa and the like of the lower end support portions 74A to 74C. For example, bonding or welding. The lengths of the support pins 75A, 75B, and 75C in the Z direction are such that the connection pins 74Aa and the like of the lower end support portions 74A to 74C are accommodated in the notches 54f and the like of the wafer holder 54 and the tips of the support pins 75A, 75B, and 75C. Is set to be lower than the placement surface 54a. In this embodiment, the tips of the support pins 75A, 75B, and 75C may be set at the same height as the placement surface 54a while the back surface of the wafer W is supported.

  Also in this embodiment, three sets of support pins 75A to 75C are disposed so as to surround three positions set at substantially equal angular intervals along the circumference CT in the wafer holder 54. As an example, suction holes 75Aa, 75Ba, and 75Ca for vacuum suction (suction) are respectively formed in the centers of the support pins 75A, 75B, and 75C, and these suction holes 75Aa to 75Ca are formed in exhaust holes inside the shaft portion 74Ab. Communicate. Note that the support pins 75A to 75C and the lower end support portion 74A (or 74B and 74C) can be formed by integrally forming by molding or the like and then polishing the tips of the support pins 75A to 75C. In this case, the suction holes 75Aa to 75Ca may be formed by, for example, forming holes penetrating the centers and side surfaces of the support pins 75A to 75C and then closing the bottom and side openings with a filler or the like. Also in this example, it is not necessary for all of the support pins 75A, 75B, and 75C to have a suction hole for vacuum suction, and at least one of the support pins 75A to 75C has a suction hole for vacuum suction. There may be.

  A lifting part 47D (supporting member) that includes three sets of support pins 75A to 75C, three lower end support parts 74A to 74C, and a driven part 46, supports the back surface of the wafer W and can be raised and lowered in the Z direction. It is configured. Moreover, the branch part is comprised from the support pins 75A-75C, the lower end support parts 74A-74C, and the corresponding support | pillar part 46b. The suction holes 75Aa to 75Ca of the support pins 75A to 75C communicate with the negative pressure space NP in the main body portion 46c via the exhaust passage a3 in the column portion 46b, and the negative pressure space NP is a flexible exhaust pipe 60. Is communicated with the exhaust pipe 61C. The other configuration is the same as that of the embodiment of FIGS. 4A and 4B, and the wafer holder control system 51 controls the opening and closing of the valves V3 and V4, so that the wafer W is formed by three sets of support pins 75A to 75C. It is possible to control the start and release of adsorption due to negative pressure. Furthermore, the back surface of the wafer W can be supported by the tips of the support pins 75A to 75C by raising the lift unit 47B in the + Z direction, and the support pins 75A to 75C can be supported by lowering the lift unit 47B in the -Z direction. The wafer W can be delivered from the tip to the mounting surface 54a of the wafer holder 54.

  According to this embodiment, a plurality of (three in FIG. 11 (A)) support pins 75A to 75C (second struts) connected to the three strut portions 46b branched from the main body portion 46c of the elevating / lowering portion 47D. Since the back surface of the wafer W is sucked and supported, local deformation of the wafer W is suppressed when the wafer W is supported by the elevating unit 47D. For this reason, when the wafer W to be held is placed on the placement surface 54a (target position) of the wafer holder 54, even if the wafer W is large, reduction in local flatness of the wafer W is suppressed. it can.

  Further, in the present embodiment, in a state in which the wafer W is placed on the placement surface 54a of the wafer holder 54 (a state in which the elevating part 47D is lowered to the lowest position), the connecting parts of the lower end support parts 74A to 74C of the elevating part 47D. 74Aa and the like are located between the mounting surface 54a and the bottom surface 54e of the wafer holder 54. For this reason, the wafer holder 54 and the Z stage 53 need only be provided with three through holes for the shaft portions 74Ab of the three lower end support portions 74A to 74C. Is easy to assemble.

  Also in the present embodiment, a film (for example, a diamond-like carbon film) for improving slippage may be formed on the surface of the support pins 75A to 75C made of, for example, silicon carbide ceramics, in contact with the wafer W. Further, the number, shape, and / or arrangement of the support pins 75A to 75C may be different from each other, and the positions where the support pins 75A to 75C and the like are arranged may be four or more.

In the above embodiment, the wafer W is circular with a diameter of 300 to 450 mm, but the size of the wafer W is arbitrary, and the wafer W may have a diameter smaller than 300 mm or larger than 450 mm.
Further, in the above embodiment, the main body 46 c of the driven unit 46 is disposed below the bottom surface of the wafer holder 54, but the main body 46 c is disposed in a recess (not shown) provided on the bottom surface of the wafer holder 54. May be.
Needless to say, it is also within the technical scope of the present invention to realize a wafer holding apparatus by appropriately combining the structure shown in the first embodiment and the structure shown in the second embodiment.

  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, the substrate can be held on the wafer stage with high flatness. Thus, it is possible to manufacture the electronic device with high accuracy while maintaining high exposure accuracy.

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, 8, 8A ... wafer holding apparatus, 43A-43C ... branch part, 44A-44C ... lower end support part, 45A-45C, 75A-75C ... support Pins 46... Driven parts 47, 47 A and 47 B. Elevating parts (support members) 50. Mechanism parts 51. Wafer holder control system 52. Adsorption mechanisms 54. Wafer holders 56.

Claims (23)

A substrate holding device for holding a substrate,
A substrate holder on which the substrate is placed;
A support member that is provided so as to be movable up and down with respect to the substrate holding portion and sucks and supports the back surface of the substrate;
A drive device for raising and lowering the support member,
The support member is
A main body part in which a negative pressure space in which a negative pressure for suction is generated is formed;
A plurality of branch parts branched from the main body part,
Each of the branch portions has a plurality of support portions for supporting the back surface of the substrate,
A substrate holding apparatus, wherein a suction port communicating with the negative pressure space is provided in at least one of the plurality of support portions.   2. The substrate holding apparatus according to claim 1, wherein the branch portion includes a first support column branched from the main body portion in a direction intersecting a direction in which the support member moves up and down.   The substrate holding apparatus according to claim 2, wherein at least two of the first support columns are branched from the main body.   The substrate holding apparatus according to claim 3, wherein the number of the first support columns is three.   The substrate holding apparatus according to claim 2, wherein the first support column is cylindrical.   The said branch part contains the 1st support | pillar branched from the said main-body part, and the some 2nd support | pillar which each has the said support part and branches from the said 1st support | pillar. Substrate holding device.   The substrate holding apparatus according to claim 6, wherein the substrate holding part is formed with a recess capable of accommodating the main body part.   2. The substrate holding apparatus according to claim 1, wherein the branch portion includes a plurality of second support columns each having the support portion and branching from the main body portion.   The substrate holding apparatus according to claim 6, wherein each of the branch portions has at least two second support columns.   The substrate holding apparatus according to claim 6, wherein each of the plurality of second support columns extends along a direction in which the support member moves up and down.   The substrate holding device according to any one of claims 6 to 10, wherein at least two of the plurality of second pillars included in each of the branch portions have different cross-sectional sizes.   The substrate holding device according to any one of claims 6 to 11, wherein at least two of the plurality of second pillars included in each of the branch portions have shapes different from each other.   The substrate holding device according to any one of claims 6 to 12, wherein an end of the plurality of second support columns that can contact at least one of the support portions has a circular shape.   The substrate holding apparatus according to any one of claims 6 to 12, wherein an end portion of the plurality of second support columns that can contact at least one of the support portions has a prismatic shape.   The substrate holding device according to claim 1, wherein the plurality of branch portions are branched from the main body portion so as to be substantially equiangularly spaced around the main body portion. The substrate has a disk shape with a diameter of about 450 mm,
The substrate holding device according to any one of claims 1 to 15, wherein each of the suction ports is disposed such that a distance from a center of the substrate holding unit is within a range of 90 mm to 175 mm. A plurality of protrusions are provided in a region of the substrate holding unit where the substrate is placed,
The substrate holding apparatus according to claim 6, wherein the plurality of second support columns are arranged between the plurality of protrusions.   The substrate holding device according to any one of claims 6 to 14 and claim 17, wherein the substrate holding portion is formed with a plurality of through holes into which the second support columns are respectively inserted. In an exposure apparatus that illuminates a pattern with exposure light and exposes the substrate through the pattern with the exposure light,
A substrate holding device according to any one of claims 1 to 18, for holding a substrate to be exposed,
A stage for holding and moving the substrate holding device;
An exposure apparatus comprising: A method for holding a substrate using the substrate holding apparatus according to claim 1,
Raising the end portion of the support member relative to the substrate holding portion and sucking and supporting the back surface of the substrate at the end portion;
Lowering the support member relative to the substrate holding device;
Delivering the substrate from the support portion of the support member to the substrate holding portion;
A substrate holding method. In an exposure method of illuminating a pattern with exposure light and exposing the substrate through the pattern with the exposure light,
Holding the substrate using the substrate holding method according to claim 20;
Moving the substrate to an exposure position;
An exposure method comprising: Forming a pattern of a photosensitive layer on a substrate using the exposure apparatus according to claim 19;
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 21;
Processing the substrate on which the pattern is formed;
A device manufacturing method including:

Images