JP2014003259A - Load method, substrate holding apparatus, and exposure apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To load a wafer without causing distortion.SOLUTION: A wafer stage includes: a wafer holder WH which holds a wafer W; multiple vertical motion pins 34a, 34b, 34b which support the wafer W through the wafer holder WH; and a driving device 94 which drives the multiple vertical motion pins 34a, 34b, 34c and pushes out/pulls in the vertical motion pins 34a, 34b, 34c from an upper surface of the wafer holder WH. At least one of the vertical motion pins 34a, 34b, 34c is formed so as to be shorter than the other vertical motion pins, and the wafer W held by the multiple vertical motion pins inclines relative to the upper surface of the wafer holder WH. This structure allows the wafer W to be loaded onto the wafer holder WH without causing the distortion.

Description

  The present invention relates to a loading method, a substrate holding apparatus, and an exposure apparatus, and in particular, includes a loading method for loading a substrate onto a substrate holding member, a substrate holding apparatus suitable for carrying out the loading method, and the substrate holding apparatus. The present invention relates to an exposure apparatus.

  In lithography processes for manufacturing electronic devices (microdevices) such as semiconductor elements and liquid crystal display elements, step-and-repeat type reduction projection exposure apparatuses (so-called steppers) or step-and-scan type reduction projection exposure are mainly used. An apparatus (a so-called scanning stepper (also called a scanner)) or the like is used.

  In this type of exposure apparatus, a substrate holding member (holder) that holds a substrate to be exposed is provided on a substrate stage, and a substrate is exchanged with respect to the holder using a substrate transport system. Substrate replacement is generally performed by the following procedure. That is, the exposed substrate held by the holder is lifted from below by the vertical movement member through the holder by the vertical movement member provided on the substrate stage, and the substrate is unloaded from the unload arm (part of the substrate transport system). ). Next, the unloaded arm is retracted from above the holder, whereby the exposed substrate is transported from the substrate stage (holder). Next, the load arm (a part of the substrate transport system) transports the substrate before exposure above the substrate stage (holder), and the vertical movement member rises to receive the substrate from the load arm and further rises. Next, after the load arm is retracted, the vertically moving member is lowered, so that the substrate is placed on the holder and is sucked and held by the holder (see, for example, Patent Document 1).

  However, wafers used in the manufacture of substrates, such as semiconductor devices, are becoming larger and the arrival of the 450 mm wafer age with a diameter of 450 mm is imminent. Even with the current 300 mm wafer, for example, after the load arm is retracted, the outer peripheral edge of the wafer supported by the vertical movement member hangs down, and when the wafer is vacuumed by the holder as the vertical movement member descends, suction starts from the peripheral edge of the wafer As a result, the distortion gradually remains in the center of the wafer after adsorption. This distortion at the center of the wafer is expected to be more likely to occur with a 450 mm wafer.

US Patent Application Publication No. 2009/0213347

  According to a first aspect of the present invention, there is provided a loading method for loading a substrate having a pattern forming surface on a surface thereof onto a substrate holding member, wherein a plurality of protruding members protruding from the substrate mounting surface of the substrate holding member. The back surface of the substrate is supported by the plurality of protruding members protruding from the substrate mounting surface in a first state in which each protruding amount gradually increases or decreases from one side of the substrate holding member toward the other side. And, in order from the protruding member having a small protruding amount from the substrate mounting surface among the plurality of protruding members, lowering the substrate mounting surface and placing the substrate on the substrate mounting surface And a loading method is provided.

  According to this, it is possible to load the substrate onto the substrate holding member without causing residual strain in the substrate.

  According to the second aspect of the present invention, there is provided a substrate holding device for holding a substrate, the placement surface on which the substrate is placed, the first position protruding from the placement surface, and the placement surface. A substrate holding member having a plurality of projecting members that move between a second position that does not project, and a plurality of projecting members and the substrate for adjusting a projecting amount of the plurality of projecting members from the mounting surface. When at least one of the holding members is driven and the substrate is loaded onto the substrate holding member, the protruding amount of each of the plurality of protruding members protruding from the mounting surface of the substrate holding member is equal to one of the substrate holding members. There is provided a substrate holding device comprising: a driving device that is set to a first state that gradually increases or decreases from the side toward the other side.

  According to this, it is possible to load the substrate onto the holding portion of the substrate holding member without causing residual strain in the substrate.

  According to a third aspect of the present invention, there is provided an exposure apparatus that exposes a substrate with an energy beam, the substrate holding apparatus on which the substrate is placed on the mounting surface, and the energy beam on the substrate. An exposure apparatus is provided that includes a pattern generation apparatus that irradiates and forms a pattern on the substrate.

  According to this, the exposure accuracy of the substrate can be improved.

It is a figure which shows schematically the structure of the exposure apparatus which concerns on one Embodiment. It is a top view which shows the wafer stage of FIG. FIG. 3 is a view partially showing a configuration of a wafer stage and omitting a part thereof. It is a block diagram which shows the input / output relationship of the main controller which mainly comprises the control system of the exposure apparatus of one Embodiment. FIGS. 5A and 5B are views (No. 1) for explaining loading of a wafer onto a wafer stage (wafer holder). 6A and 6B are views (No. 2) for explaining the loading of the wafer onto the wafer stage (wafer holder). FIGS. 7A and 7B are views for explaining the configuration of the wafer stage according to the first and second modifications, respectively. FIG. 8A is a view for explaining a basic configuration of a wafer stage according to a third modification example in which a gap sensor is provided in the wafer holder, and FIGS. 8B and 8C are respectively a first view. FIG. 10 is a diagram for explaining a wafer loading operation when a gap sensor is provided on a wafer stage according to a second modification. FIG. 9A is a plan view showing a wafer stage according to a fourth modification, and FIG. 9B is a view for explaining loading of the wafer onto the wafer stage (wafer holder). It is a top view which shows the wafer stage which concerns on a 5th modification. FIGS. 11A to 11C are views for explaining loading of a wafer onto a wafer stage (wafer holder) according to a fifth modification.

  Hereinafter, an embodiment will be described with reference to FIGS. 1 to 6B.

  FIG. 1 shows a schematic configuration of an exposure apparatus 100 according to an embodiment. The exposure apparatus 100 is a step-and-scan projection exposure apparatus, a so-called scanner. As will be described later, in the present embodiment, a projection optical system PL is provided. In the following description, a reticle and wafer are arranged in the Z-axis direction in a direction parallel to the optical axis AXp of the projection optical system PL and in a plane perpendicular to the Z-axis direction. And the direction perpendicular to the Z and Y axes is the X axis direction, and the rotation (tilt) directions around the X, Y, and Z axes are θx, θy, And the θz direction will be described.

  The exposure apparatus 100 includes an illumination system IOP, a reticle stage RST that holds a reticle R, a projection unit PU that projects a pattern image formed on the reticle R onto a wafer W coated with a sensitive agent (resist), and a wafer W. A wafer stage WST that holds and moves in the XY plane, a control system thereof, and the like are provided.

  The illumination system IOP includes a light source and an illumination optical system connected to the light source via a light transmission optical system, and is in the X-axis direction (in FIG. 1) on the reticle R limited (set) by the reticle blind (masking system). A slit-like illumination area IAR that is elongated in the direction perpendicular to the paper surface is illuminated with illumination light (exposure light) IL with substantially uniform illuminance. The configuration of the illumination system IOP is disclosed in, for example, US Patent Application Publication No. 2003/0025890. Here, as an example, ArF excimer laser light (wavelength 193 nm) is used as the illumination light IL.

  Reticle stage RST is arranged below illumination system IOP in FIG. On reticle stage RST, reticle R having a circuit pattern or the like formed on its pattern surface (lower surface in FIG. 1) is placed. The reticle R is fixed on the reticle stage RST, for example, by vacuum suction.

  The reticle stage RST can be finely driven in a horizontal plane (XY plane) by a reticle stage drive system 11 (not shown in FIG. 1, see FIG. 4) including a linear motor, for example, and also in a scanning direction (paper surface in FIG. 1). It can be driven in a predetermined stroke range in the Y axis direction which is the inner left / right direction. Position information of the reticle stage RST in the XY plane (including rotation information in the θz direction) is formed on the end face of the reticle stage RST by a reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 14. For example, with a resolution of about 0.25 nm. The measurement information of reticle interferometer 14 is supplied to main controller 20 (not shown in FIG. 1, see FIG. 4).

  Projection unit PU is arranged below reticle stage RST in FIG. The projection unit PU includes a lens barrel 45 and a projection optical system PL held in the lens barrel 45. As the projection optical system PL, for example, a refractive optical system including a plurality of optical elements (lens elements) arranged along the optical axis AXp parallel to the Z-axis direction is used. The projection optical system PL is, for example, both-side telecentric and has a predetermined projection magnification (for example, 1/4 times, 1/5 times, or 1/8 times). For this reason, when the illumination area IAR on the reticle R is illuminated by the illumination light IL from the illumination system IOP, the reticle R in which the first surface (object surface) of the projection optical system PL and the pattern surface are substantially coincided with each other is arranged. With the illumination light IL that has passed through the projection optical system PL (projection unit PU), a reduced image of the circuit pattern of the reticle R in the illumination area IAR (a reduced image of a part of the circuit pattern) is projected through the projection optical system PL (projection unit PU). Is formed in a region (hereinafter also referred to as an exposure region) IA that is conjugated to the illumination region IAR on the wafer W, which is disposed on the second surface (image surface) side of the wafer W, the surface of which is coated with a resist (sensitive agent). . Then, by synchronous driving of reticle stage RST and wafer stage WST, reticle R is moved relative to illumination area IAR (illumination light IL) in the scanning direction (Y-axis direction) and exposure area IA (illumination light IL). By moving the wafer W relative to the scanning direction (Y-axis direction), scanning exposure of one shot area (partition area) on the wafer W is performed, and a reticle pattern is transferred to the shot area. .

  As shown in FIG. 1, wafer stage WST includes a stage main body 52 and a wafer table WTB mounted on stage main body 52. Wafer stage WST is driven on stage base 22 with a predetermined stroke in the X-axis direction and Y-axis direction by stage drive system 24 including, for example, a linear motor and the like, and in Z-axis direction, θx direction, θy direction, and θz. Micro-driven in the direction. The stage drive system may be constituted by a magnetically levitated planar motor.

  Wafer W is fixed on wafer table WTB by, for example, vacuum suction via wafer holder WH (not shown in FIG. 1, refer to FIG. 2).

  FIG. 2 shows a plan view of wafer stage WST with no wafer W together with a supply / exhaust mechanism of wafer holder WH. Further, FIG. 3 shows the AA line sectional view of FIG.

  As shown in FIG. 2, a wafer holder WH having substantially the same size as wafer W is fixed to the upper surface of wafer stage WST, that is, the center of the upper surface of wafer table WTB.

  As shown in the plan view of FIG. 2, the wafer holder WH has a central portion excluding an annular region having a predetermined width near the outer periphery of the base portion 26 and the upper surface of the base portion 26 (the front surface in FIG. 2). A plurality of projecting pin portions 32 provided at predetermined intervals in a region of a predetermined area, and an annular convex portion (hereinafter referred to as an outer peripheral edge) provided in the vicinity of the outer periphery in a state surrounding the region where the plurality of pin portions 32 are disposed. , Generally referred to as “rim portion”) 28 and the like.

  The wafer holder WH is made of a material having a low expansion coefficient, for example, ceramics and the like, and by etching the surface of the material such as disk-shaped ceramics as a whole, a circular plate-like base portion 26 constituting the bottom surface portion, and this base portion 26. A rim portion 28 and a plurality of pin portions 32 that are projected on the upper surface are integrally formed. The outer diameter of the rim portion 28 is set to be slightly smaller than the outer diameter of the wafer W, for example, about 1 to 2 mm. The upper surface of the rim portion 28 is between the rear surface of the wafer W when the wafer W is placed. Are processed horizontally and flatly so that no gap is formed.

  As shown in FIG. 3, the pin portion 32 has a protrusion-like shape in which each tip portion is positioned on the same plane as the rim portion 28. These pin portions 32 are arranged along a plurality of concentric circles centering on a reference point on the base portion 26, here the center point.

  In the wafer holder WH configured as described above, in the manufacturing stage, as described above, after the base portion 26, the pin portion 32, and the rim portion 28 are integrally formed, a plurality of wafer holders WH that finally become contact surfaces with the wafer W are provided. The upper end surface of the pin portion 32 and the upper surface of the rim portion 28 are polished using a polishing device, abrasive grains, or the like. As a result, the upper end surfaces of the plurality of pin portions 32 and the upper surface of the rim portion 28 are located on substantially the same plane. In the present embodiment, a wafer placement surface WMS of the wafer holder WH is formed by a surface connecting the upper end surfaces of the plurality of pin portions 32 (coincident with the upper surface of the rim portion 28).

  Returning to FIG. 2, in the vicinity of the center of the base portion 26, three through holes 84 (not shown in FIG. 2, refer to FIG. 3) in the vertical direction (perpendicular to the plane of the drawing) at the positions of the respective apexes of the equilateral triangle, It is formed in a state that does not mechanically interfere with the pin portion 32. As shown in FIG. 3, these three through holes 84 are formed through the base portion 26 of the wafer holder WH and the wafer table WTB in the Z-axis direction (vertical direction). Vertical movement pins 34a, 34b, and 34c having a cylindrical shape are inserted into the three through holes 84, respectively. The three vertical movement pins 34a, 34b, and 34c are driven by a driving device 94 to be described later, so that the upper end portion of each of the three vertical movement pins 34a, 34b, and 34c passes through the through holes 84 and the wafer mounting surface WMS (that is, the plurality of pin portions 32). It can move up and down between a first position (upper limit movement position) that protrudes above the surface connecting the upper end surfaces and a second position (lower limit movement position) where the upper end portion does not protrude above the wafer placement surface WMS. It is. In the present embodiment, the lower limit movement position of each of the three vertical movement pins 34a, 34b, 34c is set to the same position as the upper surface of the base portion 26 or a position below the same. As shown in FIG. 3, the three vertical movement pins 34 a, 34 b, and 34 c are plate members 92 that are arranged in parallel to the XY plane and constitute a part of the drive device 94 (which will be described later). It is fixed to the upper surface of each. In the present embodiment, the lengths (heights) of the three vertical movement pins 34a, 34b, and 34c in the Z-axis direction are not uniform, and as an example, as shown in FIG. The vertical movement pin 34a is the lowest, the highest vertical movement pin 34c located on the -Y side is the highest, and the remaining vertical movement pins 34b are intermediate in height. More specifically, the upper end surfaces of the three vertical movement pins 34a, 34b, 34c are planes parallel to a plane in which the connecting surfaces are orthogonal to the YZ plane and form a predetermined angle θ with respect to the XY plane. Each height is set so that

  The three vertical movement pins 34a, 34b, and 34c are driven by the driving device 94 so that the vertical movement pins 34a, 34b, and 34c can move up and down by the same amount in the vertical direction (Z-axis direction) simultaneously. Therefore, in the present embodiment, the above-described first position and second position of the three vertical movement pins 34a, 34b, and 34c are different from each other.

  At the time of wafer loading and wafer unloading, which will be described later, the three vertical movement pins 34a, 34b, and 34c are driven by the driving device 94 so that the wafer W is supported from below by the three vertical movement pins 34a, 34b, and 34c. It can be moved up and down while the wafer W is supported. In addition, it is also possible to use a tubular member as each of the three vertical movement pins 34a, 34b, and 34c. In this case, the wafer W can be sucked and held by connecting the lower end of each vertical movement pin to a vacuum device (not shown) such as a vacuum pump and operating the vacuum device when supporting the wafer W.

  Returning to FIG. 2, a plurality of air supply / exhaust ports 36 are provided on the upper surface of the base portion 26 in the radial direction from the vicinity of the central portion of the upper surface of the base portion 26 (directions of three radii having a central angle interval of approximately 120 °). Are formed at predetermined intervals. These air supply / exhaust ports 36 are also formed at positions that do not mechanically interfere with the pin portion 32. The air supply / exhaust port 36 is in communication with the air supply / exhaust branch pipes 40a, 40b, 40c connected to the outer peripheral surface of the base portion 26 via supply / exhaust passages 38A, 38B, 38C formed inside the base portion 26, respectively. Has been. The air supply / exhaust branch pipes 40a, 40b, 40c constitute a part of an air supply / exhaust mechanism 80 described later.

  Each of the air supply / exhaust passages 38A, 38B, and 38C includes a main passage formed along the radial direction from the outer peripheral surface of the base portion 26 to the vicinity of the center portion of the base portion 26, and a predetermined interval in the radial direction from the main passage. And a plurality of branch paths each branched in the + Z direction. In this case, the opening end at the upper end of each of the plurality of branch paths is the aforementioned air supply / exhaust port 36.

  The wafer W mounted on the wafer holder WH and supported from below by the plurality of pin portions 32 and the rim portion 28 is placed on the wafer holder WH on the upper end surfaces (upper end portions) of the plurality of pin portions 32 and the rim portion 28. An air supply / exhaust mechanism 80 including a vacuum suction mechanism for sucking and holding is connected.

  As shown in FIG. 2, the air supply / exhaust mechanism 80 includes a vacuum pump 46A and an air supply device 46B, and an air supply / exhaust pipe 40 that connects the vacuum pump 46A and the air supply device 46B to the air supply / exhaust passages 38A to 38C, respectively. And.

  The supply / exhaust pipe 40 includes a supply / exhaust main pipe 40d, the above-described supply / exhaust branch pipes 40a, 40b, 40c branched from the one end of the supply / exhaust main pipe 40d, and two from the other end of the supply / exhaust main pipe 40d. The exhaust branch pipe 40e and the supply branch pipe 40f are branched into two.

  A vacuum pump 46A is connected to the end of the exhaust branch pipe 40e opposite to the supply / exhaust main pipe 40d. An air supply device 46B is connected to the end of the air supply branch pipe 40f opposite to the air supply / exhaust main pipe 40d.

  Further, a pressure sensor 97 (not shown in FIG. 2, see FIG. 4) for measuring the air pressure inside the supply / exhaust pipe 40 is connected to a part of the supply / exhaust main pipe 40d. The measured value of the pressure sensor 97 is supplied to the main controller 20, and the main controller 20 controls the vacuum pump 46A and the air supply device based on the measured value of the pressure sensor 97 and the control information for loading and unloading the wafer. 46B is controlled on / off (operation / non-operation). Instead of performing on / off control of the vacuum pump 46A and the air supply device 46B, the exhaust pump 40A and the air supply branch 40g are respectively connected to the vacuum pump 46A and the air supply via valves (not shown) such as electromagnetic valves. A device 46B may be connected to control the opening and closing of these valves. Further, in place of the air supply / exhaust mechanism 80 of the present embodiment, a first vacuum pump for normal vacuum exhaust as disclosed in, for example, US Pat. No. 6,710,857 is used at the time of wafer loading. A high-pressure exhaust vacuum chamber, a second vacuum pump, and an air supply / exhaust mechanism including an air supply device may be used.

  As shown in FIG. 3, the drive device 94 includes a drive shaft 93 having one end (upper end) fixed to the lower surface of the plate-like member 92, and a drive mechanism 95 that drives the drive shaft 93 in the vertical direction. ing. The drive mechanism 95 includes, for example, a motor (rotary motor or linear motor) as a drive source, and drives the drive shaft 93 in the vertical direction via the power transmission mechanism by the driving force of the motor. The drive mechanism 95 is fixed on the bottom wall 52 a of the stage main body 52.

  Returning to FIG. 1, position information (rotation information (yaw amount (rotation amount θz in θz direction), pitching amount (rotation amount θx in θx direction)), rolling amount (rotation amount θy direction in θy direction) of wafer stage WST in the XY plane. ))) Is always detected by a laser interferometer system (hereinafter abbreviated as “interferometer system”) 18 through the movable mirror 16 with a resolution of, for example, about 0.25 nm. Here, actually, as shown in FIG. 2, the wafer stage WST includes a Y moving mirror 16Y having a reflecting surface orthogonal to the Y axis and an X moving mirror 16X having a reflecting surface orthogonal to the X axis. It has been fixed. Correspondingly, an interferometer system 18 is configured including a Y interferometer and an X interferometer that irradiates a length measuring beam to each of the Y movable mirror 16Y and the X movable mirror 16X. In FIG. These are typically shown as moving mirror 16 and interferometer system 18.

  The measurement information of the interferometer system 18 is supplied to the main controller 20 (see FIG. 4). Main controller 20 controls the position (including rotation in the θz direction) of wafer stage WST in the XY plane via stage drive system 24 based on the measurement information of interferometer system 18.

  Although not shown in FIG. 1, the position and the amount of tilt in the Z-axis direction of the surface of the wafer W held by the wafer holder WH are disclosed in, for example, US Pat. No. 5,448,332. It is measured by a focus sensor AF (see FIG. 4) comprising an oblique incidence type multi-point focal position detection system. The measurement information of the focus sensor AF is also supplied to the main controller 20 (see FIG. 4).

  A reference plate FP (see FIG. 2) whose surface is the same height as the surface of wafer W is fixed on wafer stage WST. A plurality of reference marks including a pair of first marks detected by a reticle alignment detection system (to be described later) and a second mark used for baseline measurement of the alignment detection system AS are formed on the surface of the reference plate FP. ing.

  Further, an alignment detection system AS that detects an alignment mark and a reference mark formed on the wafer W is provided on the side surface of the lens barrel 45 of the projection unit PU. As an example of the alignment detection system AS, a mark is illuminated with broadband light such as a halogen lamp, and the mark position is measured by image processing of the mark image, which is a type of image-forming alignment sensor. An FIA (Field Image Alignment) system is used.

  In exposure apparatus 100, a pair of TTR (Through The Reticle) alignment systems using light having an exposure wavelength disclosed in, for example, US Pat. No. 5,646,413, for example, above reticle stage RST. A reticle alignment detection system 13 (not shown in FIG. 1, refer to FIG. 4) is provided. The detection signal of the reticle alignment detection system 13 is supplied to the main controller 20 (see FIG. 4).

  FIG. 4 is a block diagram showing the input / output relationship of the main controller 20 that centrally configures the control system of the exposure apparatus 100 and performs overall control of each component. The main controller 20 includes a workstation (or a microcomputer) and the like, and comprehensively controls each part of the exposure apparatus 100.

  Next, a series of operations performed by the exposure apparatus 100 configured as described above will be described with a focus on wafer exchange operations (wafer loading and unloading operations).

  For example, when processing the wafer at the head of the lot, the reticle R is first loaded on the reticle stage RST, and the main controller 20 causes the pair of reticle alignment detection systems 13 and the pair of first marks on the reference plate FP, Using the two marks, for example, reticle alignment and baseline measurement of the alignment detection system AS are performed according to the procedure disclosed in US Pat. No. 5,646,413.

  Next, at a wafer exchange position (not shown), a wafer W coated with a sensitive material (resist) is loaded onto wafer holder WH of wafer stage WST by a coater / developer (not shown) connected in-line to exposure apparatus 100, for example. The The loading of the wafer W is performed according to the following procedure. In the following description, the description of the wafer adsorption and desorption from the load arm, unload arm, vertical movement pins, etc. is omitted.

  First, as indicated by a white arrow in FIG. 5A, the wafer W is transferred above the wafer holder WH by the load arm 96A constituting a part of the wafer transfer system. Next, the main controller 20 causes the vertical movement pins 34a, 34b, 34c to move in the + Z direction toward the above-described upper limit movement position via the driving device 94, as indicated by black arrows in FIG. Driven. During this movement, the wafer W supported by the load arm 96A is supported from below by the vertical movement pins 34a, 34b, and 34c, and the vertical movement pins 34a, 34b, and 34c are further driven upward, whereby the wafer W is moved. The load arm 96A is transferred to the vertical movement pins 34a, 34b, 34c.

  In the present embodiment, the height of the upper end surfaces of the vertical movement pins 34a, 34b, and 34c is set so as to increase linearly in order, so that the wafer W is as shown in FIG. The wafer holder WH is supported by the vertical movement pins 34a, 34b, and 34c from below while forming an angle θ with respect to the upper surface (XY plane) of the wafer holder WH (the + Y side is inclined downward).

Next, as indicated by a white arrow in FIG. 5B, the load arm 96A is retracted from above the wafer holder WH. After the load arm 96A is retracted, the main control device 20 causes the vertical movement pins 34a, 34b, 34c to move to the above-described lower limit movement position via the drive device 94, as indicated by a solid arrow in FIG. It is driven in the −Z direction toward the vicinity. Accordingly, as shown in FIG. 6A, since the vertical movement pins 34a are lower than the other vertical movement pins 34b and 34c with respect to the upper surface of the wafer holder WH, the + Y side of the wafer W is the upper surface of the wafer holder WH. (The rim portion 28 and the upper surfaces of the plurality of pin portions 32) abut. Further, when the vertical movement pins 34a, 34b, and 34c are driven in the −Z direction by the driving device 94, the vertical movement pins 34a are moved to a position lower than the upper surface of the wafer holder WH as shown in FIG. 6B. In addition, since the vertical movement pins 34b are lower than the other vertical movement pins 34c with respect to the wafer holder WH, they contact the wafer mounting surface WMS of the wafer holder WH in order from the + Y side to the −Y side. The wafer W is loaded on the wafer holder WH. At this time, the above-described vacuum pump 46A is operated by the main controller 20, and the wafers W are vacuum-sucked to the wafer holder WH in order from the portion in contact with the wafer mounting surface WMS of the wafer holder WH. In this case, the wafer W is sucked and held by the wafer holder WH sequentially from the + Y side to the −Y side instead of from the peripheral part to the central part, and thus is held by the wafer holder WH without causing residual distortion.
In the present embodiment, as an example, the state in which the wafer W forms an angle θ with respect to the XY plane is a state in which the + Y side is inclined downward, that is, a state in which the height gradually increases from the + Y side to the −Y side. As described above, the wafer W can be loaded on the wafer holder WH in a state where the −Y side is inclined downward, that is, in a state where the height gradually decreases from the + Y side to the −Y side. Further, not limited to the + Y side and the −Y side, the wafer W may be tilted in the + X side, the −X side, or other directions as an angle θ with respect to the XY plane.

  After loading the wafer W, the main controller 20 performs alignment measurement (for example, EGA) for detecting a plurality of alignment marks on the wafer W using the alignment detection system AS. Thereby, arrangement coordinates of a plurality of shot areas on the wafer W are obtained. Details of alignment measurement (EGA) are disclosed in, for example, US Pat. No. 4,780,617.

  Next, the main controller 20 performs an inter-shot stepping operation for moving the wafer W to an acceleration start position for exposure of a plurality of shot areas on the wafer W based on the alignment measurement result, and the above-described scanning exposure operation. Step-and-scan exposure operations are repeated, and the pattern of the reticle R is sequentially transferred to all shot areas on the wafer W. The step-and-scan exposure operation is not different from the conventional one, and a detailed description thereof will be omitted.

  When the exposure is completed, the exposed wafer W is unloaded from wafer holder WH of wafer stage WST in the following procedure.

  That is, first, wafer stage WST moves to a predetermined wafer exchange position, and main controller 20 stops the operation of vacuum pump 46A and starts the operation of air supply device 46B, and air supply / exhaust from air supply device 46B. Pressurized air is ejected to the back side of the wafer W through the port 36. As a result, the vacuum suction of the wafer W by the wafer holder WH on which the wafer W is levitated from the wafer mounting surface WMS of the wafer holder WH is released. Next, the main controller 20 drives the vertical movement pins 34a, 34b, 34c via the drive device 94 in the + Z direction toward the aforementioned movement upper limit position. While the vertical movement pins 34a, 34b, and 34c are being raised, the wafer W is supported by the vertical movement pins 34a, 34b, and 34c from below and lifted to the upper limit movement position. When the vertical movement pins 34a, 34b, and 34c are raised, each of the vertical movement pins 34a, 34b, and 34c can hold the back surface of the wafer W by suction.

  Next, an unload arm (not shown) constituting a part of the transfer system is inserted below the wafer W supported by the vertical movement pins 34a, 34b, 34c. Next, the main control device 20 drives the vertical movement pins 34a, 34b, 34c to descend to a predetermined standby position (a predetermined position between the upper limit movement position and the lower limit movement position) (driven in the −Z direction). . During the downward movement of the vertical movement pins 34a, 34b, 34c, the wafer W is transferred from the vertical movement pins 34a, 34b, 34c to the unload arm. Thereafter, the unload arm holds and retracts the wafer W. Thereafter, the operations after the loading of the wafer W are repeatedly performed, and a plurality of wafers in the lot are sequentially processed. After the lot processing is completed, the same processing is repeatedly performed on the wafer of the next lot.

  As described above, in the exposure apparatus 100 according to the present embodiment, the wafer stage WST includes the rim portion 28 and the plurality of pin portions 32 that support the wafer W to be mounted, and the base on which these are provided. A wafer holder WH having a portion 26 and a wafer table WTB to which the wafer holder WH is fixed are provided. The base portion 26 and the wafer table WTB are formed with a plurality of (for example, three) through-holes 84 penetrating them vertically. Wafer stage WST has an upper limit movement position at which its upper end protrudes above wafer mounting surface WMS of wafer holder WH and a lower limit movement position that does not protrude above wafer mounting surface WMS via each of a plurality of through holes 84. In order to adjust the protrusion amount of the plurality of (for example, three) vertical movement pins 34a, 34b, 34c and the three vertical movement pins 34a, 34b, 34c from the wafer mounting surface WMS that can move vertically between And a drive device 94 that drives the three vertical movement pins 34a, 34b, and 34c. The three vertical movement pins 34a, 34b, and 34c are fixed to the upper surface of the plate-like member 92 parallel to the horizontal plane, and the height (Z position) of each upper end surface is increased in order.

  Then, the main controller 20 performs a loading method for loading the wafer W onto the wafer holder WH according to the following procedure. That is, when the wafer W is transported above the wafer holder WH by the load arm 96A, the three vertical movement pins 34a, 34b, and 34c are driven to rise through the through holes 84 formed in the wafer holder WH and the wafer table WTB. As a result, the amount of protrusion of the three vertical movement pins 34a, 34b, 34c from the wafer mounting surface WMS of the wafer holder WH gradually increases from the + Y side to the −Y side of the wafer holder WH. . The three vertical movement pins 34a, 34b, and 34c are further driven to rise, whereby the wafer W is supported from below by the three vertical movement pins 34a, 34b, and 34c protruding from the wafer mounting surface WMS. Then, after the load arm 96A is retracted, of the three vertical movement pins 34a, 34b, and 34c, the vertical movement pins 34a having a small protrusion amount from the wafer mounting surface WMS are sequentially lowered below the wafer mounting surface WMS. As a result, the wafer W is loaded on the wafer holder WH with the back surface thereof in contact with the wafer mounting surface WMS in the order from the + Y side to the −Y side. At this time, the wafer W starts to be sucked by the wafer holder WH in order from the portion where the back surface thereof is in contact with the wafer mounting surface WMS. As a result, it becomes possible to load the wafer W onto the wafer holder WH without causing residual distortion after holding.

  Further, according to the exposure apparatus 100 according to the present embodiment, since the wafer W can be loaded on the wafer holder WH without causing residual distortion, an improvement in exposure accuracy is expected.

  In the above embodiment, the lengths of the three vertical movement pins 34a, 34b, 34c are made different so that the amount of protrusion of the vertical movement pins 34a, 34b, 34c from the wafer mounting surface WMS of the wafer holder WH is different. By setting the wafer holder WH so as to gradually increase from the + Y side to the −Y side, the wafer W supported (held) by the plurality of vertical movement pins 34a, 34b, 34c is placed on the wafer mounting surface of the wafer holder WH. Although not limited to this, the wafer holder WH is integrated with the wafer table WTB (or like the wafer stage according to the first modification shown in FIG. 7A) (or, for example). The wafer holder WH alone) may be configured to be tiltable with respect to the stage main body 52 via a drive mechanism (not shown). In this case, the lengths of the three vertical movement pins 34a, 34b, 34c may be different as in the above embodiment, but may be the same length. Even in the latter case, as shown in FIG. 7A, the wafer holder WH is integrated with the wafer table WTB with respect to the wafer W supported by the three vertical movement pins 34a, 34b, 34c (or , Only the wafer holder WH), for example, by tilting the wafer holder WH by a predetermined angle in the θx direction so that the + Y side of the wafer holder WH is higher than the −Y side, the three vertical movement pins 34a, 34b, 34c are moved to the respective wafer holders WH. The amount of protrusion from the wafer placement surface WMS may be set to gradually increase from the + Y side to the −Y side of the wafer holder WH. In this case, while maintaining the inclination of the wafer holder WH (wafer table WTB) and driving the plurality of vertical movement pins 34a, 34b, and 34c in the −Z direction via the driving device 94, the wafer W is moved from the + Y side. The wafer W can be loaded on the wafer holder WH without causing residual strain by causing the wafer Y to contact the upper surface of the wafer holder WH sequentially in the −Y side.

  In the wafer stage according to the first modification, the gap between the through hole 84 for inserting the vertical movement pins 34a, 34b, 34c provided in the wafer holder WH (and the wafer table WTB) and the vertical movement pins 34a, 34b, 34c. The tiltable angle of wafer holder WH (and wafer table WTB) is determined by the dimensions. Therefore, it is desirable to determine the diameter of the through hole in consideration of the diameters of the vertical movement pins 34a, 34b, and 34c and the thickness of the wafer holder WH (and the wafer table WTB) so that a necessary inclination angle can be obtained. Since the wafer holder WH and the vertical movement pins 34a, 34b, 34c need only be relatively inclined, the vertical movement pins 34a, 34b, 34c can be inclined with respect to the wafer holder WH.

In addition, as the wafer stage according to a second modified example shown in FIG. 7 (B), a plurality of vertical movement pins 34a, 34b, respectively 34c supporting member 92 ₁ a plurality of driven individually via A driving device 94 may be provided. In such a case, the positions of the upper end surfaces of the plurality of vertical movement pins 34a, 34b, 34c are adjusted so as to gradually increase from the + Y side to the -Y side, for example, by each of the plurality of driving devices 94 ( That is, by adjusting the protrusion amount of the vertical movement pins 34a, 34b, 34c from the wafer mounting surface WMS), the wafer W held by the plurality of vertical movement pins 34a, 34b, 34c is mounted on the wafer holder WH. Tilt to the plane WMS. By maintaining the inclination and driving the vertical movement pins 34a, 34b, and 34c in the −Z direction by a plurality of driving devices 94 in synchronization with each other, the wafers W are loaded on the wafer holder WH in order from the + Y side to the −Y side. The wafer W can be loaded on the wafer holder WH without causing distortion by being brought into contact with the mounting surface WMS.

  Further, in the wafer stage according to the first and second modifications described above, as shown in FIG. 8A, the wafer holder WH (or wafer table WTB) supports a plurality of vertical movement pins 34a, 34b, 34c. A plurality of gap sensors 96 are provided for measuring the gap between the target wafer W and the upper surface of the base portion 26 of the wafer holder WH (a surface parallel to the wafer mounting surface WMS), and the surface shape of the wafer W is measured by the gap sensors 96. It is good also as comprising a surface shape measuring device. In this case, for example, when the plurality of vertical movement pins 34a, 34b, 34c are lifted to receive the wafer W supported by the load arm 96A, the main controller 20 determines the surface shape measuring instrument (gap). The surface shape (surface shape of the back surface) of the wafer W is measured by the sensor 96). The above measurement is preferably continued until the vertical movement pins 34a, 34b, 34c receive the wafer W from the load arm 96A and the load arm 96A is retracted. For example, in the case of the wafer stage according to the first modification described above (see FIG. 7A), based on the measurement result, as shown in FIG. 8B, a plurality of vertical movement pins 34a, By raising the + Y side and lowering the −Y side of the wafer holder WH (wafer table WTB) with respect to the wafer W held by 34b, 34c (see the black arrow in FIG. 8B), the vertical movement pins 34a, The protrusion amounts of the wafers 34b and 34c from the wafer placement surface WMS are varied, and the wafer W is tilted with respect to the wafer placement surface WMS of the wafer holder WH.

  Alternatively, for example, in the case of the wafer stage according to the second modification described above (see FIG. 7B), as shown in FIG. 8C based on the measurement result of the surface shape measuring instrument (gap sensor 96). In addition, the plurality of driving devices 94 drive the vertical movement pins 34a arranged on the + Y side in the −Z direction and the vertical movement pins 34c arranged on the −Y side in the + Z direction, respectively (in FIG. 8C). Thus, the amount of protrusion of the vertical movement pins 34a, 34b, 34c from the wafer mounting surface WMS is varied, and the wafer W is tilted with respect to the wafer mounting surface WMS of the wafer holder WH.

  8B and 8C, the plurality of vertical movement pins 34a, 34b, and 34c are driven in the −Z direction while maintaining the inclination of the wafer W, and the wafer W is moved to the + Y side. The wafer W can be loaded on the wafer holder WH without causing distortion by bringing it into contact with the upper surface of the wafer holder WH sequentially from -Y side.

  Further, by tilting the wafer W with respect to the upper surface of the wafer holder WH as described above, the position of the wafer W (the end thereof) in the XY plane is shifted. For example, as shown in FIG. 9B, when the wafer W is tilted around the X axis, the position in the Y axis direction is shifted. Let the deviation be ΔY. Therefore, by providing another driving device that finely drives the vertical movement pins 34a, 34b, and 34c in the Y-axis direction (and the X-axis direction), a plurality of pins are provided as shown by arrows in FIG. Each of the vertical movement pins 34a, 34b, 34c is configured so as to be minutely driven in the X-axis and Y-axis directions. Then, as shown in FIG. 9B, the positional deviation ΔY due to the tilt of the wafer W may be corrected by driving each of the plurality of vertical movement pins 34a, 34b, 34c by a distance ΔY in the + Y direction. good. The positional deviation ΔY can be obtained by measuring the tilt of the wafer W using the above-described surface shape measuring instrument (gap sensor 96) and calculating using the measurement result.

  In addition, as shown in the plan view of FIG. 10, the back surface of the wafer W is sucked and held by vacuum suction or the like via the wafer holder WH (and the wafer table WTB) separately from the plurality of vertical movement pins 34a, 34b and 34c. A plurality of support members 98 that can be independently driven in the Z-axis direction may be further provided. In wafer stage WST according to the modification shown in FIG. 10, a plurality of support members 98 are arranged radially about the center of wafer holder WH, specifically, on eight straight lines with a central angle of 45 °. The number and arrangement of the plurality of support members 98 are not limited to the number and arrangement shown in FIG. In such a case, as shown in FIG. 11A, main controller 20 uses a surface shape measuring instrument (gap sensor 96) to support the wafer W while supporting wafer W with a plurality of vertical movement pins 34a, 34b, 34c. The surface shape of W (surface shape of the back surface) is measured. Then, based on the measurement result, each of the plurality of support members 98 is driven in the + Z direction. The plurality of support members 98 suck and support the wafer W by vacuum suction or the like when the tips of the plurality of support members 98 contact the back surface of the wafer W. Then, as shown in FIG. 11 (B), the main controller 20 sets the plurality of support members 98 and the plurality of vertical movement pins 34a, 34b, 34c so that their upper end positions are the same. Drive in + Z direction or -Z direction. As a result, as shown in FIG. 11C, the wafer W is supported in parallel and flat with the wafer mounting surface WMS above the wafer holder WH. Then, by maintaining the state and driving the plurality of support members 98 and the plurality of vertical movement pins 34a, 34b, 34c in the -Z direction, the wafer W can be loaded on the wafer holder WH without causing distortion. it can.

In the above-described embodiment and modifications (hereinafter abbreviated as the above-described embodiment), the case where the exposure apparatus is a dry-type exposure apparatus that exposes the wafer W without using liquid (water) has been described. For example, as disclosed in European Patent Application Publication No. 1,420,298, International Publication No. 2004/055803, U.S. Patent No. 6,952,253, and the like, The above embodiment is also applied to an exposure apparatus that forms an immersion space including an optical path of illumination light between the projection optical system and the wafer, and exposes the wafer with illumination light through the liquid in the projection optical system and the immersion space. can do.
Further, when loading the wafer W onto the wafer holder W, a low friction material (for example, DLC (diamond-like) is applied to the surface of the rim portion 28 and / or the plurality of pin portions 32 of the wafer holder W in order to reduce residual strain generated in the wafer. Carbon) and the like).

  In the above-described embodiment, the case where the exposure apparatus is a scanning exposure apparatus such as a step-and-scan method has been described. However, the exposure apparatus is not limited to this, and may be a stationary exposure apparatus such as a stepper. The above-described embodiment can also be applied to a step-and-stitch reduction projection exposure apparatus, a proximity exposure apparatus, or a mirror projection aligner that synthesizes a shot area and a shot area.

  Further, the projection optical system in the exposure apparatus of the above embodiment may be not only a reduction system but also any of the same magnification and enlargement systems, and the projection optical system PL may be any of a reflection system and a catadioptric system as well as a refraction system. The projected image may be either an inverted image or an erect image. In addition, the illumination area and the exposure area described above are rectangular in shape, but the shape is not limited to this, and may be, for example, an arc, a trapezoid, or a parallelogram.

The light source of the exposure apparatus of the above embodiment is not limited to the ArF excimer laser, but is a KrF excimer laser (output wavelength 248 nm), F ₂ laser (output wavelength 157 nm), Ar ₂ laser (output wavelength 126 nm), Kr ₂ laser ( It is also possible to use a pulse laser light source with an output wavelength of 146 nm, an ultrahigh pressure mercury lamp that emits a bright line such as g-line (wavelength 436 nm), i-line (wavelength 365 nm), and the like. A harmonic generator of a YAG laser or the like can also be used. In addition, as disclosed in, for example, US Pat. No. 7,023,610, a single wavelength laser beam in an infrared region or a visible region oscillated from a DFB semiconductor laser or a fiber laser is used as vacuum ultraviolet light. For example, a harmonic that is amplified by a fiber amplifier doped with erbium (or both erbium and ytterbium) and wavelength-converted into ultraviolet light using a nonlinear optical crystal may be used.

  In the above embodiment, it is needless to say that the illumination light IL of the exposure apparatus is not limited to light having a wavelength of 100 nm or more, and light having a wavelength of less than 100 nm may be used. For example, the above embodiment can be applied to an EUV exposure apparatus that uses EUV (Extreme Ultraviolet) light in a soft X-ray region (for example, a wavelength region of 5 to 15 nm). In addition, the above embodiment can be applied to an exposure apparatus that uses charged particle beams such as an electron beam or an ion beam.

  Further, as disclosed in, for example, US Pat. No. 6,611,316, two reticle patterns are synthesized on a wafer via a projection optical system, and 1 on the wafer by one scan exposure. The above embodiment can also be applied to an exposure apparatus that performs double exposure of two shot areas almost simultaneously.

  In the above embodiment, the object on which the pattern is to be formed (the object to be exposed to which the energy beam is irradiated) is not limited to the wafer, but may be another object such as a glass plate, a ceramic substrate, a film member, or a mask blank. good.

  The use of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, but for example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern to a square glass plate, an organic EL, a thin film magnetic head, an image sensor (CCD, etc.), micromachines, DNA chips and the like can also be widely applied to exposure apparatuses. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates or silicon wafers, etc. The above embodiment can also be applied to an exposure apparatus that transfers a circuit pattern.

  An electronic device such as a semiconductor element includes a step of designing a function / performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and the exposure apparatus (pattern forming apparatus) of the above-described embodiment. And a lithography step for transferring the mask (reticle) pattern to the wafer by the exposure method, a development step for developing the exposed wafer, and an etching step for removing the exposed member other than the portion where the resist remains by etching, It is manufactured through a resist removal step for removing a resist that has become unnecessary after etching, a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like. In this case, in the lithography step, the exposure method described above is executed using the exposure apparatus of the above embodiment, and a device pattern is formed on the wafer. Therefore, a highly integrated device can be manufactured with high productivity.

  DESCRIPTION OF SYMBOLS 20 ... Main control apparatus, 24 ... Stage drive system, 34a, 34b, 34c ... Vertical movement pin, 94 ... Drive apparatus, 96 ... Gap sensor, 100 ... Exposure apparatus, IL ... Illumination light, IOP ... Illumination system, PL ... Projection Optical system, PU ... projection unit, W ... wafer, WH ... wafer holder, WMS ... wafer mounting surface, WST ... wafer stage, WTB ... wafer table.

Claims (13)

A loading method for loading a substrate having a pattern forming surface on a surface onto a substrate holding member,
In the first state, the amount of protrusion of each of the plurality of protruding members protruding from the substrate mounting surface of the substrate holding member gradually increases or decreases from one side to the other side of the substrate holding member. Supporting the back surface of the substrate on the plurality of protruding members protruding from the mounting surface;
Lowering the substrate placement surface in order from a projection member having a small projection amount from the substrate placement surface among the plurality of projection members, and placing the substrate on the substrate placement surface. Loading method. Prior to the supporting, raising the plurality of projecting members, and further measuring the distance between the back surface of the substrate and the reference surface parallel to the substrate mounting surface at a plurality of locations,
The loading method according to claim 1, wherein the first state is set based on a result of the measurement.   The plurality of protrusions in the first state based on an inclination angle determined by a positional relationship between two protrusion members of the plurality of protrusion members in the first state and a protrusion amount from the substrate placement surface. The loading method according to claim 1, further comprising: obtaining a shift amount of the substrate when the substrate is supported by a member.   The loading method according to claim 1, further comprising starting suction from a portion of the substrate placed on the substrate placement surface and in contact with the substrate placement surface. A substrate holding device for holding a substrate,
A substrate holding member having a mounting surface on which the substrate is mounted, and a plurality of protruding members that move between a first position protruding from the mounting surface and a second position not protruding from the mounting surface; ,
In order to adjust the amount of protrusion of the plurality of protruding members from the mounting surface, at least one of the plurality of protruding members and the substrate holding member is driven, and the substrate is loaded when the substrate is loaded onto the substrate holding member. A driving device configured to set a first state in which the protruding amount of each of the plurality of protruding members protruding from the mounting surface of the holding member gradually increases or decreases from one side of the substrate holding member toward the other side; A substrate holding apparatus comprising:   The projecting amount from the mounting surface parallel to the horizontal plane is set so that each of the plurality of projecting members is in the same state as the first state when each of the plurality of projecting members is in the first position. 5. The substrate holding device according to 5. Each of the plurality of projecting members is set to have the same length so that the projecting amounts from the placement surface set to be parallel to the horizontal plane are the same when each is in the first position. Has been
The substrate holding member is configured to be tiltable with respect to the horizontal plane, and the driving device tilts the substrate holding member with respect to the horizontal plane to bring the plurality of protruding members into the first state. The substrate holding device according to claim 5, wherein the substrate holding device is set. The plurality of projecting members can individually move up and down,
The substrate holding device according to claim 5, wherein the driving device drives the plurality of protruding members individually. A plurality of sensors that measure the distance between the mounting surface or the reference surface parallel to the mounting surface of the back surface of the substrate when the plurality of protruding members are raised;
The substrate holding device according to claim 8, wherein the driving device drives at least one of the plurality of protruding members and the substrate holding member based on measurement results of the plurality of sensors.   The substrate holding apparatus according to claim 5, wherein the plurality of projecting members are configured to be drivable even in a plane parallel to the placement surface of the substrate holding member.   The drive device is in the first state based on an inclination angle determined by a positional relationship between two of the plurality of protruding members in the first state and a protruding amount from the mounting surface. The plurality of projecting members are driven in a plane parallel to the mounting surface of the substrate holding member at a distance and a direction corresponding to a shift amount of the substrate when the substrate is supported by the plurality of projecting members. Item 11. The substrate holding device according to Item 10.   12. The substrate holding device according to claim 5, wherein each of the plurality of projecting members supports the substrate for delivery to and from a substrate transport system when in the first position. . An exposure apparatus that exposes a substrate with an energy beam,
The substrate holding device according to any one of claims 5 to 12, wherein the substrate is placed on the placement surface,
An exposure apparatus comprising: a pattern generation device that forms a pattern on the substrate by irradiating the energy beam on the substrate.

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