JP2010153407A - Cleaning method and device, and exposure method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device that hardly leaves foreign matter on an object to be cleaned. <P>SOLUTION: The cleaning device, which cleans a wafer holder WH capable of moving at least along an XY plane while holding a wafer, includes: a grinding stone 33 which can be placed on the wafer holder WH; a vertical moving mechanism 34 which places the grinding stone 33 on the wafer holder WH; and a wafer stage WST which continuously and relatively moves the grinding stone 33 and wafer holder WH in a period that the grinding stone 33 is placed on the wafer holder WH. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cleaning technique for cleaning a member holding an object such as a photosensitive substrate, an exposure technique using the cleaning technique, and a device manufacturing technique using the exposure technique.

For example, in an exposure apparatus such as a batch exposure type projection exposure apparatus such as a stepper or a scanning exposure type projection exposure apparatus such as a scanning stepper used in a lithography process for manufacturing an electronic device (microdevice) such as a semiconductor device If the exposure is continued, the resist residue peeled off from the photoresist applied to the wafer (or glass plate or the like) to be exposed may adhere to the wafer holder, and the local flatness of the wafer may be lowered. In such a case, in order to clean the wafer holder, an exposure apparatus having a cleaning device including a mechanism for effecting a cleaning member on the wafer holder has been proposed (see, for example, Patent Document 1). According to this cleaning device, the contact surface of the wafer holder with the wafer can be automatically cleaned by bringing the cleaning member into contact with the wafer holder and moving the wafer holder via the wafer stage.
JP 2008-166616 A

When the wafer holder is cleaned using a conventional cleaning device, there is a risk that a slight amount of foreign matter (a trace of the cleaning member) arranged in the shape of the cleaning member remains on the wafer holder.
Usually, a large number of pins are arranged on the contact surface of the wafer holder with the wafer, and the foreign matter removed from the pins by the cleaning device remains in the recesses between the pins on the upper surface of the wafer holder. There was a risk that the remaining foreign matter would adhere to the pins again.

  In view of such circumstances, it is an object of the present invention to provide a cleaning technique in which foreign matter hardly remains on an object to be cleaned, an exposure technique using the cleaning technique, and a device manufacturing method using the exposure technique.

  A first cleaning device according to the present invention is a cleaning device that cleans an object holding member that holds an object and is movable along at least a plane, and a cleaning member that can be placed on the object holding member; A movable member that places the cleaning member on the object holding member, and the cleaning member and the object holding member are continuously relative to each other within a period in which the cleaning member is placed on the object holding member. And a moving mechanism that moves.

  A second cleaning device according to the present invention is a cleaning device that cleans an object holding member that holds an object and is movable at least along a plane, and a cleaning member that can be placed on the object holding member; A movable member for placing the cleaning member on the object holding member, and a movement for relatively moving the cleaning member and the object holding member within a period in which the cleaning member is placed on the object holding member. A mechanism and a suction device that sucks foreign matter on the object holding member are provided.

A cleaning method according to the present invention is a cleaning method for cleaning an object holding member that holds an object and is movable at least along a plane, and the cleaning member is placed on the object holding member, and the cleaning is performed. During the period in which the member is placed on the object holding member, the cleaning member and the object holding member are moved relative to each other to suck the foreign matter on the object holding member.
Further, the exposure method according to the present invention includes a step of cleaning a contact surface of the object holding member with the object using the cleaning device of the present invention in the exposure method for forming a pattern on the object, and the object holding member. Placing the object thereon, moving the object holding member along a plane, and forming the pattern on the object.

An exposure apparatus according to the present invention is an exposure apparatus for forming a pattern on an object, an object holding member for holding the object, an optical system for forming a pattern on the object held by the object holding member, and the object holding And a cleaning device of the present invention for cleaning a member.
A device manufacturing method according to the present invention includes forming a pattern of a photosensitive layer on a substrate using the exposure method or exposure apparatus of the present invention, and processing the substrate on which the pattern is formed. .

  According to the present invention, the cleaning member and the object holding member are continuously moved relative to each other within the period in which the cleaning member is placed on the object holding member, or on the object holding member. By sucking in the foreign matter, it becomes difficult for the foreign matter to remain on the object holding member (cleaning target).

Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic block diagram that shows an exposure apparatus EX of the present embodiment. In FIG. 1, an exposure apparatus EX includes an illumination optical system IL that illuminates a mask M on which a transfer pattern is formed with exposure light EL, a mask stage MST that supports the mask M, and a mask that is illuminated with exposure light EL. A projection optical system PL that projects an image of an M pattern onto a projection area AR1 on the wafer W, a wafer stage WST that supports the wafer W, and a control device CONT that includes a computer that controls the overall operation of the exposure apparatus EX; A liquid supply mechanism 10 that supplies liquid Lq onto wafer W for application of the liquid immersion method, a liquid recovery mechanism 20 that recovers liquid Lq supplied onto wafer W, and wafer W of wafer stage WST are held. And a cleaning device 30 for cleaning the wafer holder WH.

  In the exposure apparatus EX, at least during transfer of the pattern image of the mask M onto the wafer W, the liquid Lq supplied from the liquid supply mechanism 10 causes the optical element at the image plane side end portion of the projection optical system PL (this embodiment). Then, a local space between the plano-convex lens 2 having a substantially flat bottom surface and the surface of the wafer W arranged on the image plane side is filled. The liquid Lq is supplied to the liquid immersion area AR2 including the projection area AR1 on the wafer W and collected.

  In the present embodiment, as the exposure apparatus EX, a scanning exposure apparatus (so-called scanning stepper) that exposes a pattern formed on the mask M onto the wafer W while moving the mask M and the wafer W synchronously in a predetermined scanning direction. The case of using is described as an example. Hereinafter, the Z-axis is taken in parallel to the optical axis AX of the projection optical system PL, and the X-axis is taken in the scanning direction along the synchronous movement direction (scanning direction) of the mask M and the wafer W in a plane perpendicular to the Z-axis. A description will be given by taking the Y axis along a direction perpendicular to (non-scanning direction). In the present embodiment, the XY plane is substantially parallel to the horizontal plane. In addition, the rotation (inclination) directions around the X axis, the Y axis, and the Z axis are the θx, θy, and θz directions, respectively. The wafer W of this embodiment includes, for example, a mask in which a resist, which is a photosensitive agent, is applied at a predetermined thickness (for example, about 200 nm) on a disk-shaped semiconductor wafer having a diameter of about 200 mm to 450 mm. Includes a reticle on which a device pattern to be reduced and projected on the wafer W is formed.

  First, the illumination optical system IL includes an exposure light source, an optical integrator for equalizing the illuminance of the exposure light EL emitted from the exposure light source, a condenser lens for condensing the exposure light EL from the optical integrator, and a relay. A lens system and a variable field stop for setting the illumination area on the mask M by the exposure light EL in a slit shape are provided. A predetermined illumination area on the mask M is illuminated with the exposure light EL having a uniform illuminance distribution by the illumination optical system IL. As the exposure light EL, ArF excimer laser light (wavelength 193 nm) is used. In addition, as the exposure light EL, vacuum ultraviolet light such as an ultraviolet line from a mercury lamp, far ultraviolet light (DUV light) such as KrF excimer laser light (wavelength 248 nm), or harmonics of a solid laser (semiconductor laser, etc.) (VUV light) or the like is used.

  Further, the mask stage MST can hold the mask M by suction, can move two-dimensionally in an XY plane on a mask base (not shown), and can be rotated slightly in the θz direction. Mask stage MST is driven by a mask stage driving device MSTD such as a linear motor. The laser interferometer 56A disposed opposite to the movable mirror 55A on the mask stage MST actually has a measurement beam having three or more axes, and is at least in the X direction of the mask stage MST (mask M) by the laser interferometer 56A. The position in the Y direction and the rotation angle in the θz direction are measured, and the measurement result is output to the control device CONT. The control device CONT moves or positions the mask stage MST (mask M) by driving the mask stage driving device MSTD based on the measurement result.

  The projection optical system PL projects and exposes the pattern of the mask M onto the wafer W at a predetermined projection magnification β (β is a reduction magnification such as 1/4, 1/5, etc.). It is composed of a plurality of optical elements including the optical element 2 provided at the terminal portion on the surface side. Note that the projection optical system PL is not limited to a reduction system, and may be any of an equal magnification system and an enlargement system. Further, the liquid Lq (for example, pure water) in the liquid immersion area AR2 is in contact with the optical element 2 at the tip of the projection optical system PL. For example, the resist applied to the wafer W has liquid repellency that repels the liquid Lq.

  Further, a wafer table WT is fixed to the upper part of wafer stage WST, and a wafer holder WH for holding wafer W by, for example, vacuum suction is fixed to the upper part of wafer table WT. As shown in FIG. 2A described later, on the upper surface of the wafer holder WH, a large number of pins (convex portions) 37 that support the back surface of the wafer W are formed so as to surround these pins 37. A side wall WHa having the same height as the pin 37 is formed. Further, a plurality of suction holes WHb are formed between a large number of pins 37 above the wafer holder WH, and these suction holes WHb are suctioned including an external vacuum pump or the like via the exhaust holes and the flexible piping 18. It is connected to the device 17. The wafer W is held on the wafer holder WH by evacuating the space inside the side wall WHa and the back surface of the wafer W through the suction hole WHb from the suction device 17 to a negative pressure.

  In FIG. 1, a wafer stage WST supports a Z stage portion that controls the position (focus position) in the Z direction of wafer table WT (wafer W) and the inclination angle in the θx and θy directions, and moves while supporting this Z stage portion. The XY stage portion is mounted on an air plane (gas bearing) so that the XY stage portion can move in the X direction and the Y direction on a surface parallel to the XY plane on the base 54. Wafer stage WST (Z stage portion and XY stage portion) is driven by a wafer stage drive device WSTD such as a linear motor.

  A laser interferometer 56B is provided at a position facing the reflecting surface (or moving mirror) on the side surface of wafer table WT on wafer stage WST. The laser interferometer 56B also has a plurality of measurement beams. The laser interferometer 56B measures at least the position in the X direction, the Y direction, and the rotation angle in the θz direction of the wafer table WT (wafer W). It is output to the control device CONT. The control device CONT is supported by the wafer stage WST by driving the wafer stage drive device WSTD based on the measurement result and the measurement result of an autofocus sensor (not shown) that measures the position of the surface of the wafer W in the Z direction. The wafer table WT (wafer W) is moved or positioned.

  A mask alignment system 90 that measures the position of the alignment mark of the mask M is arranged above the mask stage MST, and an alignment system 91 that measures the position of the alignment mark of the wafer W is arranged on the side surface of the projection optical system PL. These alignment systems 90 and 91 align the mask M and the wafer W. On wafer stage WST, a reference mark member (not shown) for measuring a base line (positional relationship between the pattern image of mask M and the detection center of alignment system 91) is provided. In addition to wafer stage WST, a measurement stage equipped with a measuring device or the like for measuring the imaging characteristics of projection optical system PL may be arranged.

  Further, an annular and flat liquid-repellent plate portion 97 is provided on the wafer table WT in FIG. 1 so as to surround the wafer W on the wafer holder WH. The upper surface of the plate portion 97 is a flat surface having substantially the same height as the surface of the wafer W held by the wafer holder WH. Although there is a gap of about 0.1 to 1 mm between the edge of the wafer W and the plate portion 97, the resist applied to the wafer W is usually liquid repellent and the liquid Lq has surface tension. Therefore, the liquid Lq hardly flows into the gap, and the liquid Lq can be held between the plate portion 97 and the projection optical system PL even when the vicinity of the periphery of the wafer W is exposed.

  Next, the configuration of the local liquid immersion mechanism including the liquid supply mechanism 10 and the liquid recovery mechanism 20 in FIG. 1 will be described. The liquid supply mechanism 10 includes a liquid supply unit 11 that can deliver the liquid Lq, and a supply pipe 12 that connects one end of the liquid supply unit 11 to the liquid supply unit 11. The liquid recovery mechanism 20 includes a liquid recovery unit 21 that can recover the liquid Lq, and a recovery pipe 22 that is connected to the liquid recovery unit 21 at one end thereof. A nozzle member (flow path forming member) 15 is disposed in the vicinity of the optical element 2 at the end of the projection optical system PL. The nozzle member 15 is an annular member provided so as to surround the tip of the optical element 2 above the wafer W (wafer stage WST). The nozzle member 15 constitutes a part of the liquid supply mechanism 10 and the liquid recovery mechanism 20.

  In a state where the projection area AR1 of the projection optical system PL is on the wafer W, the nozzle member 15 includes, for example, supply ports 13 and 14 disposed so as to face the side surface of the optical element 2, and an internal supply channel 82A. , 82B. One end of the supply channel 82A is connected to the supply port 13, and the supply port 14 is connected to the supply channel 82A through the supply channel 82B, and the other end of the supply channel 82A is connected to the supply pipe 12. To the liquid supply unit 11. Further, the nozzle member 15 includes a rectangular or circular frame-shaped recovery port 24 disposed so as to face the surface of the wafer W, and a large number of small holes are formed in a mesh shape so as to cover the recovery port 24. A mesh filter 25 that is a porous member is fitted. The recovery port 24 is connected to the liquid recovery unit 21 via the recovery flow path 84 and the recovery pipe 22 in the nozzle member 15. A region surrounded by the recovery port 24 is a liquid immersion region AR2 to which almost the liquid Lq is supplied.

  The detailed configuration of the local liquid immersion mechanism including the liquid supply mechanism 10 and the liquid recovery mechanism 20 is disclosed in, for example, International Publication No. 2004/019128 pamphlet. In addition, as the nozzle member 15 of the local liquid immersion mechanism, for example, members of various other configurations as disclosed in International Publication No. 99/49504 pamphlet or International Publication No. 2005/122218 pamphlet can be used. is there.

  In FIG. 1, the operations of the liquid supply unit 11 and the liquid recovery unit 21 are controlled by the control device CONT. The control device CONT can control the liquid supply amount per unit time on the wafer W by the liquid supply unit 11 and can control the liquid recovery amount per unit time by the liquid recovery unit 21. The liquid Lq delivered from the liquid supply unit 11 is supplied to the liquid immersion area AR2 on the wafer W via the supply pipes 12 and the supply channels 82A and 82B of the nozzle member 15 and the supply ports 13 and 14. Then, the liquid Lq in the liquid immersion area AR2 is recovered from the recovery port 24 of the nozzle member 15 via the mesh filter 25 and then to the liquid recovery part 21 via the recovery flow path 84 and the recovery pipe 22 of the nozzle member 15. Collected.

  When the exposure apparatus EX exposes the wafer W, a partial pattern image of the mask M is projected onto the projection area AR1 by the projection optical system PL via the projection optical system PL, and the mask is applied to the projection optical system PL. In synchronization with the movement of M in the X direction at a speed V, the wafer W moves in the X direction at a speed β · V (β is a projection magnification) via the wafer stage WST. Then, after the exposure of one shot area on wafer W is completed, the next shot area on wafer W is moved to the scanning start position by step movement of wafer stage WST. In this way, the pattern image of the mask M is exposed to all shot areas on the wafer W by the step-and-scan method.

  When performing this exposure process, the controller CONT drives the liquid supply mechanism 10 to start the liquid supply operation on the wafer W. The liquid Lq delivered from the liquid supply unit 11 of the liquid supply mechanism 10 flows through the supply pipe 12 and then is supplied onto the wafer W via the supply flow paths 82A and 82B and the supply ports 13 and 14 in the nozzle member 15. Is done. The liquid Lq supplied onto the wafer W flows under the projection optical system PL in accordance with the movement of the wafer W. For example, when the wafer W is moving in the + X direction during exposure of a certain shot area, the liquid Lq moves under the projection optical system PL in the + X direction, which is the same direction as the wafer W, at almost the same speed as the wafer W. Flowing. In this state, the exposure light EL emitted from the illumination optical system IL and passing through the mask M is irradiated to the image plane side of the projection optical system PL, and the pattern image of the mask M is liquid in the projection optical system PL and the liquid immersion area AR2. The wafer W is exposed through Lq.

  The controller CONT supplies the liquid Lq onto the wafer W by the liquid supply mechanism 10 when the exposure light EL is irradiated on the image plane side of the projection optical system PL, that is, during the exposure operation of the wafer W. . On the other hand, as an example, the controller CONT uses the liquid recovery mechanism 20 to apply the liquid Lq on the wafer W when the exposure light EL is irradiated on the image plane side of the projection optical system PL, that is, during the exposure operation of the wafer W. Is not collected. As an example, the control device CONT is a part of the period after the completion of exposure of one shot area on the wafer W until the start of exposure of the next shot area (at least part of the step movement period of the wafer W). Then, the liquid recovery unit 21 recovers the liquid Lq on the wafer W.

  Now, when a large number of wafers are exposed in this way, minute foreign matters such as resist residues gradually remain on a large number of pins 37 (see FIG. 2A) of the wafer holder WH. The local flatness (local flatness) of the wafer is lowered, and the resolution of the pattern image of the mask exposed on the wafer is partially degraded. Therefore, the exposure apparatus EX of the present embodiment includes a cleaning device 30 for removing foreign matter on the wafer holder WH.

  In order to detect foreign matter on the wafer holder WH, the cleaning device 30 moves the image pickup device 32 that picks up an image of the upper portion of the wafer holder WH, a disc-shaped grindstone 33 placed on the wafer holder WH, and the grindstone 33 in the Z direction. A vertical movement mechanism 34 that moves up and down (moves), a flexible pipe 35 through which foreign matter sucked through the opening of the grindstone 33 passes, a suction device 36 that performs suction through the pipe 35, and a cleaning device 30 And a cleaning control system 31 that performs overall control of the entire operation. The imaging device 32 and the vertical movement mechanism 34 are supported by a frame (not shown). In the cleaning control system 31, an image processing unit that processes an image captured by the imaging device 32 and analyzes the distribution and amount of foreign matter on the wafer holder WH, and a control unit are provided. The control unit in the cleaning control system 31 controls the operations of the vertical movement mechanism 34 and the suction device 36 based on the foreign substance information detected by the image processing unit, the control information from the control device CONT, and the like. In response, drive information for moving wafer stage WST (wafer holder WH) along a predetermined locus in the XY plane is supplied to control unit CONT. In this case, wafer stage WST is also a mechanism for relatively moving grindstone 33 and wafer holder WH in a plane parallel to the XY plane, and wafer stage WST can be regarded as a part of cleaning device 30.

  FIG. 2A is a cross-sectional view showing a state in which the wafer W is unloaded from the wafer holder WH of FIG. 1 and the wafer holder WH is moved below the vertical movement mechanism 34 of the cleaning device 30. In FIG. 2A, the vertical movement mechanism 34 is housed in a main body member 34a having a cylindrical guide portion at the lower end, and is accommodated inside the guide portion so as to be smoothly movable in the Z direction. It has a slide member 38 to be held, a drive shaft 39 arranged to be movable in the Z direction at the center of the main body member 34a, and a drive motor 40 for moving the drive shaft 39 in the Z direction. In this case, an opening 38a is formed at the center of the slide member 38, an opening 33a larger than the opening 38a is formed at the center of the grindstone 33, and the lower end of the drive shaft 39 is smaller than the opening 33a and larger than the opening 38a. The head part 39a is connected. A slide member 38 and a grindstone 33 are suspended from the lower end of the drive shaft 39 via a head portion 39a. The contact portion of the lower end of the grindstone 33 with the wafer holder WH is a ring-shaped plane.

  Further, an exhaust hole 39b is provided in the drive shaft 39 from the center of the head portion 39a, an exhaust hole 34b is also provided in the main body member 34a so that one end communicates with the exhaust hole 39b, and the other end of the exhaust hole 34b is provided. A pipe 35 connected to the suction device 36 of FIG. 1 is connected. An exhaust hole 34b in the main body member 34a is formed so that the exhaust hole 39b and the exhaust hole 34b always communicate with each other even when the drive shaft 39 moves in the Z direction.

  In the present embodiment, the grindstone 33 is formed of a conductive material having a certain degree of conductivity. For example, silicon carbide (SiC) can be used as the conductive material, and other ceramics such as Altic or zirconia can also be used. The grindstone 33 may be formed by laminating a conductive material on the surface of the high resistance body. When the grindstone 33 is formed of a conductive material in this way, static electricity is less likely to be charged in the wafer holder WH due to peeling charging and frictional charging when the grindstone 33 leaves the wafer holder WH. As a result, the foreign matter remaining between the pins 37 of the wafer holder WH after the cleaning is hardly moved onto the pins 37, so that the local flatness of the wafer on the wafer holder WH is hardly reduced after the cleaning. .

Moreover, it is preferable that the material of the grindstone 33 has smaller mechanical characteristics including at least one of bending strength, fracture toughness (hardness to crack), and hardness as compared with the material of the wafer holder WH. When the wafer holder WH is, for example, a cemented carbide (for example, cobalt 6.5%), the bending strength of the cemented carbide is 2000 (MPa) or more, and the fracture toughness is about 12 (MN / m ^3/2 ). Therefore, when paying attention to bending strength, silicon carbide (bending strength 350 MPa), zirconia (bending strength 1100 MPa), or the like can be used as the material of the grindstone 33. When attention is paid to fracture toughness, the material of the grindstone 33 is silicon carbide (fracture toughness 3 (MN / m ^3/2 ) or so) or zirconia (fracture toughness 6 (MN / m ^3/2 ) or so). Can be used. Similarly, when focusing on the hardness, it is preferable that the hardness of the material of the grindstone 33 is smaller than the hardness of the material of the wafer holder WH. Also in these cases, the grindstone 33 is formed by laminating or adding a material having at least one of such bending strength, fracture toughness, and hardness smaller than that of the wafer holder WH on a high resistance body, for example. May be. When the material is selected in this way, when the surface of the wafer holder WH is cleaned with the grindstone 33, the pins 37 of the wafer holder WH are not cracked due to contact with the grindstone 33.

  Next, the suction device 36 in FIG. 1 is connected to a compressed air pipe 42 to which compressed air is supplied, as shown in FIG. 3A as an example. 3A, the suction device 36 includes a regulator 36a that takes in the compressed air B1 from the compressed air pipe 42, a pressure gauge 36b that measures the pressure of the compressed air B1, a vacuum ejector 36c that is connected to the regulator 36a, A filter 36d that removes foreign matter from the air B2 sucked through the opening of the grindstone 33 and the pipe 35, and the air B2 that has passed through the filter 36d is supplied to the vacuum ejector 36c. In this case, since the compressed air B1 passes through the vacuum ejector 36c, a negative pressure is generated on the pipe 35 side. Therefore, the air B2 on the pipe 35 side is also exhausted as the mixed air B3 together with the compressed air B1. The suction device 36 includes a filter 36e that removes foreign matters from the mixed air B3, and a silencer 36f that exhausts the air that has passed through the filter 36e at a low pressure. In this case, since the compressed air pipe 42 is generally provided in a normal factory, it is not particularly necessary to provide a suction vacuum pump or the like.

  Instead of the suction device 36, for example, a suction device 36A shown in FIG. 3B can be used. In FIG. 3 (B), the suction device 36A removes foreign matter from the regulator 36a connected to the negative pressure vacuum exhaust pipe 43, the pressure gauge 36b, the opening of the grindstone 33 and the air B4 sucked through the pipe 35. The air B4 is sucked to the vacuum exhaust pipe 43 side through the regulator 36a. The suction device 36 </ b> A requires the vacuum exhaust pipe 43, but has a simpler configuration than the suction device 36.

Next, an example of the operation of cleaning the wafer holder WH using the cleaning device 30 in the exposure apparatus EX of FIG. 1 will be described with reference to the flowchart of FIG. This operation is controlled by the control device CONT and the cleaning control system 31.
First, in step 101 of FIG. 4, the wafer stage WST is moved to the loading position, and an unexposed wafer W coated with a resist is loaded on the wafer holder WH via a wafer loader system (not shown). The wafer W is vacuum-sucked by the suction device 17). In the next step 102, after the wafer W is aligned using the alignment system 91, an image of the pattern of the mask M is exposed to each shot area on the wafer W by the immersion method and the scanning exposure method as described above. To do. Thereafter, wafer stage WST is moved to the unloading position, and wafer W is unloaded from wafer holder WH via a wafer loader system (not shown).

  Next, it is determined whether or not the exposure is completed (step 104). If there is a wafer to be exposed, the process proceeds to step 105 to determine whether or not the wafer holder WH is to be cleaned. This determination can also be made based on unevenness information on the surface of the wafer W measured by an autofocus sensor (not shown) with respect to the previously exposed wafer W, or the upper surface of the wafer holder WH by the imaging device 32, for example. It is also possible to carry out based on the observation result. If it is determined in step 105 that the wafer holder WH is not to be cleaned, the operation returns to step 101 and the next wafer is exposed.

  On the other hand, if it is determined in step 105 that the wafer holder WH is to be cleaned, the operation shifts to step 106 to move the center of the wafer stage WST to a cleaning position below the vertical movement mechanism 34. As a result, the center of wafer holder WH on wafer stage WST moves substantially below the center of grindstone 33 supported by vertical movement mechanism 34 as shown in FIG. In subsequent step 107, the drive shaft 39 of the vertical movement mechanism 34 is lowered in the −Z direction (here, the vertical direction), and the grindstone 33 is positioned at a position where the bottom surface of the grindstone 33 is slightly higher than the top surface of the pins 37 of the wafer holder WH. Quiesce. From this state, wafer stage WST is moved in the −X direction at a low speed, and when there is a change in the thrust of wafer stage WST, wafer stage WST is stopped and controller CONT reads the coordinates of wafer stage WST. Thus, the thrust of wafer stage WST changes, as shown in FIG. 5, means that grindstone 33 has reached a position C1 that is relatively in contact with inner peripheral wall 97a of plate portion 97 on wafer stage WST. To do.

  Similarly, by moving wafer stage WST sequentially in the + X direction, the -Y direction, and the + Y direction at low speed, positions C2 and C3 at which grindstone 33 relatively contacts inner peripheral wall 97a of plate portion 97 in FIG. , C4, the coordinates of wafer stage WST are read by control unit CONT. In this way, the controller CONT reads the coordinates of the wafer stage WST when the grindstone 33 comes into contact with the X-direction and Y-direction ends of the inner peripheral wall 97a of the plate portion 97 on the wafer stage WST. The movable range in the X and Y directions of wafer stage WST is calculated within a range in which the side surface does not come into contact with inner peripheral wall 97a, which can be substantially regarded as a part of wafer table WT, with an interval of about 1 mm, for example ( measure. Thereafter, during cleaning of wafer holder WH, wafer stage WST moves within its movable range, so that grindstone 33 can be prevented from colliding with inner peripheral wall 97a during cleaning. Further, by storing the information of the movable range, the movable range can be used when the wafer holder WH is cleaned next time.

  In the next step 108, after the wafer stage WST is driven and the center of the wafer holder WH is moved below the center of the grindstone 33, the drive shaft 39 of the vertical movement mechanism 34 is moved to the arrow A1 as shown in FIG. As shown in FIG. 2, the bottom surface of the grindstone 33 is placed on (contacted with) the plurality of pins 37 at the center of the wafer holder WH. At this time, since the head portion 39a of the drive shaft 39 moves away from the slide member 38 and moves into the opening of the grindstone 33, the grindstone 33 is placed on the wafer holder WH by its own weight. Moreover, since the slide member 38 is accommodated in the guide part of the main body member 34a, the position of the grindstone 33 in the X direction and the Y direction is fixed.

  Immediately thereafter, the suction device 36 in FIG. 1 causes the upper portion of the wafer holder WH to pass through the opening of the grindstone 33 in FIG. 2B, the exhaust hole 39b in the drive shaft 39, the exhaust hole 34b in the main body member 34a, and the pipe 35. Start sucking air containing foreign material. With this operation, as shown by a dotted line locus ST1 starting from the starting point ST1a in FIG. 6A, the center of the grindstone 33 is continuously moved outward in a spiral relative to the wafer holder WH. Stage WST is continuously driven in the X and Y directions.

  Thereafter, in step 109, as indicated by the end point ST1b of the trajectory ST1 in FIG. 6A, when the grindstone 33 reaches the peripheral portion of the wafer holder WH, the grindstone 33 relatively moves around the periphery of the wafer holder WH. , The drive shaft 39 of the vertical movement mechanism 34 is raised in the + Z direction to raise the grindstone 33 away from the wafer holder WH, and the suction by the suction device 36 is stopped. As described above, when the grindstone 33 and the wafer holder WH are in contact with each other and moved relatively, the grindstone 33 is separated from the wafer holder WH so that a small amount of foreign matter on the pins 37 of the wafer holder WH follows the shape of the grindstone 33. It is prevented that it remains as a trace.

  In this case, in the middle of step 108, as shown in FIG. 2C, the wafer holder WH gradually moves inward as shown by, for example, an arrow A2 with respect to the grindstone 33. It is removed by the grindstone 33 and peeled between the plurality of pins 37. Further, as shown in FIG. 2D, when the wafer holder WH further moves as indicated by an arrow A3, the foreign matter 41 moves into the opening of the grindstone 33 and is discharged to the pipe 35 side together with the sucked air A5. The Thereafter, before the side surface of the grindstone 33 contacts the inner peripheral wall 97a of the plate portion 97, the drive shaft 39 rises in the direction of the arrow A4, and the grindstone 33 also rises to the position of FIG. Accordingly, the foreign matter remaining on the wafer holder WH is reduced, and the foreign matter remaining between the pins 37 of the wafer holder WH is less likely to move onto the pins 37 during exposure after cleaning. Flatness is kept flat.

  In subsequent step 110, for example, the wafer stage WST is driven, and the imaging device 32 images the upper surfaces of all the pins 37 of the wafer holder WH, thereby determining whether or not the foreign matter remains beyond the allowable range. If foreign matter remains beyond the allowable range, steps 108 and 109 are repeated and the upper surface of the wafer holder WH is cleaned again with the grindstone 33. In step 110, if the foreign matter is within the allowable range, the process proceeds to step 101, where the next wafer is exposed. As described above, according to the present embodiment, the foreign matter hardly remains after the cleaning of the wafer holder WH, so that the subsequent exposure can be performed with high accuracy.

Effects and the like of this embodiment are as follows.
(1) In a first aspect, the cleaning device 30 of the present embodiment is a cleaning device that cleans a wafer holder WH that holds a wafer and is movable at least along the XY plane, and is placed on the wafer holder WH. The grindstone 33 (cleaning member), the drive shaft 38 for placing the grindstone 33 on the wafer holder WH, and the grindstone 33 and the wafer holder WH are continuously placed within a period in which the grindstone 33 is placed on the wafer holder WH. And a wafer stage WST (moving mechanism) that relatively moves.

According to this cleaning device, a slight amount of foreign matter hardly remains on the wafer holder WH in the shape of the grindstone 33, so that the foreign matter hardly remains on the wafer holder WH. Therefore, it is possible to lengthen the period until the cleaning of the wafer holder WH starts thereafter, and to increase the throughput of the exposure process.
In this case, since the grindstone 33 is relatively moved relative to the wafer holder WH in a spiral manner via the wafer stage WST, the entire upper surface of the wafer holder WH is moved by the grindstone 33 while the grindstone 33 and the wafer holder WH are continuously moved. Can be cleaned.

  6B, the center of the grindstone 33 is relatively spirally and continuously from the peripheral position ST2a to the central position ST2b with respect to the wafer holder WH. Wafer stage WST may be driven so as to move. In this case, when the wafer holder WH and the grindstone 33 are relatively moved at the center position ST2b, the vertical movement mechanism 34 is driven so that the grindstone 33 is separated from the wafer holder WH. Further, the wafer holder WH and the grindstone 33 may move relatively so as to meander, for example.

Further, since the wafer stage WST continues the relative movement between the grindstone 33 and the wafer holder WH even when the grindstone 33 moves away from the wafer holder WH, it is further difficult for foreign matters to remain on the wafer holder WH.
In addition, the cleaning device 30 includes a suction device 36 that sucks, for example, foreign matter between the plurality of pins 37 on the wafer holder WH. Therefore, the foreign matter peeled off from the pin 37 by the grindstone 33 can be efficiently recovered.

In this case, since the suction device 36 sucks foreign matter through the opening 33a of the grindstone 33, the foreign matter scraped by the grindstone 33 can be efficiently collected.
However, in the cleaning device 30 of the first aspect, the suction device 36 is not necessarily provided.
(2) Moreover, the cleaning apparatus 30 of this embodiment is a cleaning apparatus which cleans the wafer holder WH which hold | maintains a wafer and can move along an XY plane at least on 2nd viewpoint, Comprising: On the wafer holder WH A whetstone 33 that can be placed, a drive shaft 39 for placing the grindstone 33 on the wafer holder WH, and a wafer that relatively moves the grindstone 33 and the wafer holder WH within a period in which the grindstone 33 is placed on the wafer holder WH. A stage WST and a suction device 36 for sucking foreign matter on the wafer holder WH are provided.

According to this cleaning device, since the foreign matter dropped from the pins 37 of the wafer holder WH by the grindstone 33 is discharged by suction, the foreign matter is unlikely to remain on the wafer holder WH. Therefore, it is possible to lengthen the period until the cleaning of the wafer holder WH starts thereafter, and to increase the throughput of the exposure process.
Further, since the suction device 36 sucks foreign matter through the opening 33a of the grindstone 33, the foreign matter scraped off by the grindstone 33 can be efficiently collected.

In addition, a large number of pins 37 (convex portions) are provided on the surface on which the grindstone 33 on the wafer holder WH is placed, and the suction device 36 sucks foreign matter between the plurality of pins 37. Accordingly, foreign matter between the pins 37 is prevented from reattaching on the pins 37.
However, in the cleaning device 30 of the second aspect, it is not always necessary to continuously move the grindstone 33 and the wafer holder WH relative to each other during cleaning.

(3) In the cleaning device 30 of the first and second aspects described above, the grindstone 33 is formed from a conductive material. Therefore, charging of the wafer holder WH is prevented during cleaning, and reattachment of foreign matter to the wafer holder WH is suppressed.
In addition, the grindstone 33 does not necessarily need to be formed from an electroconductive material, and can also be formed from a high resistance body.

  (4) Moreover, the cleaning method using the cleaning device 30 of the present embodiment is a cleaning method for cleaning the wafer holder WH that holds the wafer and can move at least along the XY plane, and has a grindstone on the wafer holder WH. 33 is placed (the beginning of step 108), and the grindstone 33 and the wafer holder WH are relatively moved during the period in which the grindstone 33 is placed on the wafer holder WH (steps 108 and 109), and the foreign matter on the wafer holder WH. (Steps 108 and 109).

According to this cleaning method, the foreign matter dropped from the pins 37 of the wafer holder WH by the grindstone 33 is discharged by suction, so that the foreign matter hardly remains on the wafer holder WH.
Further, when the grindstone 33 and the wafer holder WH are moving relative to each other, the grindstone 33 is separated from the wafer holder WH and suction of the foreign matter is stopped (step 108). Is less likely to remain, and foreign matter on the wafer holder WH can be efficiently recovered.

Even in this cleaning method, it is not always necessary to continuously move the grindstone 33 and the wafer holder WH relative to each other within the period in which the grindstone 33 is in contact with the wafer holder WH.
(5) Further, the exposure method of the present embodiment is an exposure method for forming a pattern (for example, a latent image of the pattern of the mask M) on the wafer W. The wafer of the wafer holder WH using the cleaning device 30 of the above embodiment. Steps 106 to 109 for cleaning the contact surface with W, Steps 101 and 102 for placing the wafer W on the wafer holder WH, moving the wafer holder WH along the XY plane, and forming the pattern on the wafer W And.

Further, the exposure apparatus EX of the present embodiment is an exposure apparatus that forms a pattern on a wafer W, a wafer holder WH that holds the wafer W, and a projection optical system PL that forms a pattern on the wafer W held by the wafer holder WH. And a cleaning device 30 for cleaning the wafer holder WH.
According to these exposure methods or exposure apparatuses, foreign matter on the wafer holder WH is reduced, so that the local flatness of the wafer W is maintained well, and the entire surface of the wafer W can be exposed with high accuracy. Further, the cleaning interval of the wafer holder WH can be extended, and the throughput of the exposure process is improved.

In the above embodiment, the following modifications are possible.
(1) In the above-described embodiment, when the foreign substance on the wafer holder WH is sucked by the suction device 36, the foreign substance is sucked from the opening 33a at the center of the grindstone 33, or alternatively, the grindstone 33 contacts the wafer holder WH. Foreign matter on the wafer holder WH may be sucked through a plurality of suction holes provided on the surface. The shape of the contact surface of the grindstone 33 with the wafer holder WH may be other shapes.

  FIGS. 7A to 7H show various grindstones 33A, 33, 33B, and 33C that can be used in place of the grindstone 33 of FIG. 2A. The grindstone 33A shown in FIGS. 7A and 7B has a narrow ring-shaped contact surface 33Ab with the wafer holder WH, and sucks foreign matter through a central opening 33Aa and a plurality of suction holes 33Ac in the contact surface 33Ab. To do. The grindstone 33 shown in FIGS. 7C and 7D is provided with a plurality of suction holes 33c in the contact surface 33b of the grindstone 33 in FIG.

  In the grindstone 33B shown in FIGS. 7E and 7F, the contact surface 33Bb with the wafer holder WH has a large number of rectangular lattices, and a plurality of openings 33Ba provided in the center and a part of the contact surface 33Bb are provided. Foreign matter is sucked through the suction hole 33Bc. In the grindstone 33C shown in FIGS. 7G and 7H, the contact surface 33Cb with the wafer holder WH is a large number of radial protrusions, and a plurality of central openings 33Ca and a plurality of contact surfaces 33Cb are provided. Foreign matter is sucked through the suction hole 33Cc.

  (2) In the cleaning device 30 of the above-described embodiment, when the foreign matter on the wafer holder WH is sucked, the foreign matter is sucked upward by the suction device 36 through the opening of the grindstone 33. Alternatively, during cleaning of the wafer holder WH, the suction device 17 for vacuum-sucking the wafer in FIG. 2A may be driven to suck (discharge) foreign matter through the exhaust hole WHb of the wafer holder WH.

(3) In the above embodiment, the wafer stage WST is driven to move the grindstone 33 and the wafer holder WH relative to each other. Instead, the grindstone 33 side may be moved with respect to the stationary wafer holder WH using, for example, a robot hand.
(4) In the above embodiment, the grindstone 33 is used to clean the wafer holder WH. However, a brush-like member or the like can be used instead of the grindstone 33.

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

  In other words, the device manufacturing method forms the pattern of the photosensitive layer on the substrate (wafer) using the exposure apparatus or the exposure method of the above-described embodiment, and processes the substrate on which the pattern is formed. (Step 224). At this time, according to the above embodiment, since exposure can be performed with high accuracy and high throughput, an electronic device can be manufactured with high throughput and high accuracy.

The present invention can be applied not only when the exposure is performed with the above-described scanning exposure type exposure apparatus but also when the exposure is performed with a batch exposure type exposure apparatus such as a stepper. Furthermore, the present invention can be similarly applied to exposure using a dry exposure type exposure apparatus or a proximity 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 imaging device (CCD or the like), a micromachine, a thin film magnetic head, a MEMS (Microelectromechanical Systems), and a DNA chip. Furthermore, the present invention can also be applied to an exposure process when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

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

1 is a partially cutaway view showing an exposure apparatus used in an example of an embodiment. FIG. 1A is a cross-sectional view showing the main part of the cleaning device 30 and the wafer holder WH in FIG. 1, FIG. 3B is a cross-sectional view showing a state where the grindstone 33 is in contact with the wafer holder WH, and FIG. (D) is sectional drawing which shows the state just before separating the grindstone 33 from the wafer holder WH. (A) is a block diagram showing a configuration example of the suction device 36, (B) is a block diagram showing another suction device. It is a flowchart which shows an example of the operation | movement which cleans the wafer holder WH during exposure. 4 is a plan view showing a relative positional relationship between a grindstone 33 and an inner peripheral wall 97a of a plate portion 97. FIG. (A) is a perspective view showing a main part in a state where the wafer holder WH and the grindstone 33 are relatively moved, and (B) is a plan view showing another example of the relative movement between the wafer holder WH and the grindstone 33. (A) is a perspective view showing the bottom surface of the grindstone 33A, (B) is a bottom view of the grindstone 33A, (C) is a perspective view showing the bottom surface of the grindstone 33, (D) is a bottom view of the grindstone 33, and (E) is The perspective view which shows the bottom face of the grindstone 33B, (F) is the bottom view of the grindstone 33B, (G) is the perspective view which shows the bottom face of the grindstone 33C, (H) is the bottom view of the grindstone 33C. It is a flowchart which shows an example of the manufacturing process of an electronic device.

Explanation of symbols

  M ... Mask, MST ... Mask stage, PL ... Projection optical system, W ... Wafer, WST ... Wafer stage, WT ... Wafer table, WH ... Wafer holder, CONT ... Control device, 30 ... Cleaning device, 31 ... Cleaning control system, 33 ... Grinding wheel, 34 ... Vertical movement mechanism, 35 ... Piping, 36 ... Suction device, 37 ... Pin, 39 ... Drive shaft

Claims (18)

A cleaning device for cleaning an object holding member that holds an object and is movable at least along a plane,
A cleaning member that can be placed on the object holding member;
A movable member for placing the cleaning member on the object holding member;
A moving mechanism that continuously and relatively moves the cleaning member and the object holding member within a period in which the cleaning member is placed on the object holding member;
A cleaning device comprising:   The cleaning device according to claim 1, wherein the moving mechanism relatively moves the cleaning member in a spiral shape with respect to the object holding member.   The cleaning device according to claim 2, wherein the moving mechanism continues relative movement between the cleaning member and the object holding member even when the cleaning member moves away from the object holding member.   The cleaning device according to claim 1, wherein the moving mechanism is a stage device that moves along the plane with the object holding member fixed.   The cleaning device according to claim 1, further comprising a suction device that sucks foreign matter on the object holding member. A cleaning device for cleaning an object holding member that holds an object and is movable at least along a plane,
A cleaning member that can be placed on the object holding member;
A movable member for placing the cleaning member on the object holding member;
A moving mechanism that relatively moves the cleaning member and the object holding member within a period in which the cleaning member is placed on the object holding member;
A suction device for sucking foreign matter on the object holding member;
A cleaning device comprising: An opening is provided in the cleaning member,
The cleaning device according to claim 5, wherein the suction device sucks foreign matter on the object holding member through the opening of the cleaning member. A plurality of suction holes are provided in a contact surface of the cleaning member with the object holding member,
The cleaning device according to claim 5, wherein the suction device sucks foreign matter on the object holding member through the plurality of suction holes of the cleaning member. A plurality of convex portions are provided on the object holding surface on which the cleaning member of the object holding member is placed,
The cleaning device according to claim 5, wherein the suction device sucks foreign matter between the plurality of convex portions of the object holding member.   The cleaning device according to claim 1, wherein the cleaning member is made of a conductive material.   The cleaning device according to any one of claims 1 to 10, wherein the cleaning member has a mechanical property including at least one of bending strength, fracture toughness, and hardness smaller than that of the object holding member. A cleaning method for cleaning an object holding member that holds an object and is movable at least along a plane,
Placing a cleaning member on the object holding member;
Within a period in which the cleaning member is placed on the object holding member, the cleaning member and the object holding member are relatively moved,
A cleaning method comprising sucking foreign matter on the object holding member. An opening is provided in the cleaning member,
The cleaning method according to claim 12, wherein when the foreign matter on the object holding member is sucked, the foreign matter is sucked through the opening of the cleaning member.   14. The suction of the foreign matter is stopped by separating the cleaning member from the object holding member when the cleaning member and the object holding member are moving relative to each other. Cleaning method. In an exposure method for forming a pattern on an object,
Cleaning the contact surface of the object holding member with the object using the cleaning device according to claim 1;
An exposure method comprising: placing the object on the object holding member; moving the object holding member along a plane; and forming the pattern on the object. In an exposure apparatus that forms a pattern on an object,
An object holding member for holding the object;
An optical system for forming a pattern on the object held by the object holding member;
The cleaning device according to any one of claims 1 to 11, for cleaning the object holding member;
An exposure apparatus comprising: Forming a pattern of a photosensitive layer on a substrate using the exposure method according to claim 15;
Processing the substrate on which the pattern is formed. Forming a pattern of a photosensitive layer on a substrate using the exposure apparatus according to claim 16;
Processing the substrate on which the pattern is formed.

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