JP2008042027A - Exposure apparatus, method for exposure, and method for manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve throughput and exposure accuracy. <P>SOLUTION: The exposure apparatus is provided with a control device capable of switching first exposure control and second exposure control. The first exposure control is performed while reversing the moving direction of a wafer stage in each transfer of a reticle pattern to each of shot areas SA1 to SAn of a wafer W; and the second exposure control is performed for continuously transferring reticle patterns to a plurality of adjacent shot areas SA1 to SAn on the wafer during the movement of the wafer stage to a fixed direction without inverting the moving direction of the wafer stage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exposure apparatus and method for exposing and transferring a pattern formed on a mask onto a substrate, and a device manufacturing method.

  In the manufacture of microdevices such as semiconductor elements, liquid crystal display elements, imaging devices (CCD (Charge Coupled Device), etc.), thin film magnetic heads, etc., step-and-scan type exposure apparatuses (so-called scanning steppers) are frequently used. Yes. In the scanning stepper, every time exposure of one shot area is completed, the scanning process of the mask stage and the substrate stage is reversed and the exposure process is sequentially performed. For this reason, in the scanning stepper, the mask stage and the substrate stage are accelerated and decelerated each time a shot area is exposed, which directly leads to a decrease in throughput (the number of wafers that can be processed per unit time).

  In Patent Document 1 below, a reticle in which a plurality of patterns to be transferred to different shot areas is used, and the reticle is synchronously moved in the pattern arrangement direction to expose a plurality of shot areas in one scan. An exposure apparatus is disclosed. In such an exposure apparatus, the number of stages of acceleration / deceleration of the stage can be reduced to a fraction of the number of patterns formed on the reticle (for example, 1/2 when two patterns are formed). A decrease in synchronization accuracy due to acceleration / deceleration can be reduced, and the throughput can be improved.

Further, in Patent Document 2 below, first and second reticle stages are provided, and the first reticle stage is moved in the opposite direction while the first reticle stage is scanning, so that the first reticle stage An exposure method is disclosed in which exposure using a second reticle stage is performed in conjunction with continuous movement of the wafer stage after scanning is completed. In such an exposure method, it is possible to expose one row of shot areas among shot areas set on the wafer without acceleration / deceleration of the wafer stage.
JP-A-10-284411 Japanese Patent No. 353297

  By the way, in recent years, in order to form a fine pattern, an opportunity to use a multiple exposure technique is increasing. Here, the multiple exposure technique is a technique for performing an exposure process a plurality of times before performing a development process or the like. In other words, this is a technique in which after exposing a substrate using a certain mask, the substrate is exposed using a different mask without performing development processing or the like. In this multiplex optical technology, a decrease in throughput becomes significant, and measures to prevent this are necessary. Further, the multiple exposure technique is used to form a fine pattern, and if the exposure accuracy is reduced as the throughput is improved, the meaning of using the multiple exposure technique is diminished.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an exposure apparatus and method capable of improving throughput and exposure accuracy, and a device manufacturing method using the exposure apparatus or method.

The present invention adopts the following configuration associated with each figure shown in the embodiment. However, the reference numerals in parentheses attached to each element are merely examples of the element and do not limit each element.
In order to solve the above problems, an exposure apparatus of the present invention includes a substrate stage (WST) that can move while holding a substrate (W), and the mask (R) and the substrate stage are moved synchronously while the mask is being moved. In the exposure apparatus (EX) for transferring the pattern formed on the substrate to the plurality of partitioned areas (SA1 to SAn) on the substrate, the substrate stage is transferred each time the mask pattern is transferred to each of the partitioned areas on the substrate. First exposure control performed while reversing the moving direction of the substrate, and continuously moving to the adjacent partitioned areas on the substrate while moving the substrate stage in a certain direction without reversing the moving direction of the substrate stage. A control device (MC) capable of switching between the second exposure control for transferring the mask pattern is provided.
According to the present invention, the pattern of the mask is transferred to each of the partitioned areas on the substrate while the moving direction of the substrate stage is reversed by the first exposure control by the control device, or the substrate by the second exposure control by the control device. While moving the substrate stage in a certain direction without reversing the moving direction of the stage, the mask pattern is continuously transferred to a plurality of adjacent divided regions on the substrate. R) and a substrate (W), wherein the pattern formed on the mask is transferred to a plurality of partitioned areas (SA1 to SAn) on the substrate while the substrate (W) is moved synchronously. First exposure control performed while reversing the moving direction of the substrate each time it is transferred to each of the partitioned areas, and the substrate without reversing the moving direction of the substrate While moving in a certain direction, switching from one to the other is performed with the second exposure control for continuously transferring the mask pattern to a plurality of adjacent divided areas on the substrate.
The device manufacturing method of the present invention includes a step (S46) of exposing a device pattern (P1, P2) onto a substrate (W) using the above exposure apparatus or the above exposure method.

  According to the present invention, the first exposure control is performed while reversing the moving direction of the substrate stage each time the mask pattern is transferred to each of the partitioned areas on the substrate, and the substrate stage without reversing the moving direction of the substrate stage. The second exposure control for continuously transferring the mask pattern to a plurality of adjacent divided areas on the substrate can be switched while moving the substrate in a certain direction, and the layout of the divided areas set on the substrate can be changed. Accordingly, the first exposure control and the second exposure control can be switched according to the exposure time required for exposure or the required exposure accuracy, so that the throughput and the exposure accuracy can be improved.

  Hereinafter, an exposure apparatus and method and a device manufacturing method according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view showing a schematic configuration of an exposure apparatus according to an embodiment of the present invention. As shown in FIG. 1, the exposure apparatus EX of the present embodiment includes a reticle stage RST that holds a reticle R as a mask, a wafer stage WST that holds a wafer W as a substrate, and illumination optics that illuminates the reticle R with exposure light EL. Main control system MC for overall control of the operation of the entire system ILS, the projection optical system PL for projecting the pattern image of the reticle R illuminated by the exposure light EL onto the wafer W held on the wafer stage WST, and the exposure apparatus EX It is comprised including.

  In addition, the exposure apparatus EX of the present embodiment is an immersion type exposure apparatus to which an immersion method is applied in order to improve the resolution by substantially shortening the exposure wavelength and substantially increase the depth of focus. The liquid supply mechanism SW for supplying the liquid Lq onto the wafer W and the liquid recovery mechanism CW for recovering the liquid Lq on the wafer W are provided. The exposure apparatus EX is on the wafer W including the projection region PR of the projection optical system PL by the liquid Lq supplied from the liquid supply mechanism SW during at least the exposure operation for transferring the pattern of the reticle R onto the wafer W. A liquid immersion region WR is formed in a part. Specifically, the exposure apparatus EX fills the space between the optical element 1 at the front end (end portion) of the projection optical system PL and the surface of the wafer W with the liquid Lq, and the reticle via the projection optical system PL and the liquid Lq. The R pattern image is projected onto the wafer W to expose the wafer W.

  An exposure apparatus EX shown in FIG. 1 is a scanning exposure apparatus (a so-called scanning stepper) that transfers a pattern formed on a reticle R onto a wafer W while moving the reticle R and the wafer W synchronously. Although details will be described later, the exposure apparatus EX of the present embodiment includes two reticle stages RST. In the following description, when two reticle stages RST are distinguished, they are referred to as “reticle stage RST1” and “reticle stage RST2”, respectively. In the following description, an XYZ orthogonal coordinate system is set in the drawing as needed, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. The direction that coincides with the optical axis AX of the projection optical system PL is the Z-axis direction, and the synchronous movement direction (scanning direction) between the reticle R and the wafer W in the plane perpendicular to the Z-axis direction is the Y-axis direction, Z-axis direction, and Y A direction (non-scanning direction) perpendicular to the axial direction is set as the X-axis direction. Further, the rotation (inclination) directions around the X, Y, and Z axes are set to the θX, θY, and θZ directions, respectively.

  The exposure apparatus EX includes a main column 2 that supports the reticle stage RST and the projection optical system PL. The main column 2 is installed on a base plate 3 placed horizontally on the floor surface. The main column 2 is formed with an upper step 2a and a lower step 2b that protrude inward. The illumination optical system ILS is supported by a support column 4 fixed to the upper part of the main column 2. The illumination optical system ILS illuminates the reticle R with the exposure light EL, an optical integrator that equalizes the illuminance of the light beam emitted from the exposure light source, a condenser lens that collects the exposure light EL from the optical integrator, A relay lens system and a variable field stop for setting the illumination area on the reticle R by the exposure light EL to a long and narrow rectangular shape (slit shape) are provided.

  FIG. 2 is a side view showing a reticle individual optical system that guides the exposure light EL through the illumination optical system ILS and the reticle R to the projection optical system PL provided in the exposure apparatus EX according to the embodiment of the present invention. As shown in FIG. 2, the illumination optical system ILS includes a transmission illumination system 40a that transmits and illuminates the reticle R1 using the exposure light EL1 from the exposure light source LS1, and a reticle R2 that uses the exposure light EL2 from the exposure light source LS2. And a transmission illumination system 40b for transmitting illumination. In addition, a reticle individual optical system 41 that guides the exposure light beams EL1 and EL2 via the reticles R1 and R2 to the projection optical system PL is provided.

  The transmission illumination system 40a includes a correction lens 42a and a reflection mirror 43a. The correction lens 42a corrects the irradiation position and irradiation shape of the exposure light EL1 that is irradiated onto the reticle R1. Here, the exposure light EL1 is formed into a slit extending in the X direction by a variable field stop (not shown) included in the illumination optical system ILS before entering the correction lens 42a. The reflection mirror 43a is disposed above (+ Z direction) the reticle stay RST1, and deflects the exposure light EL1 transmitted through the correction lens 42a downward (−Z direction).

  The transmission illumination system 40b includes a correction lens 42b and a reflection mirror 43b. The correction lens 42b corrects the irradiation position and irradiation shape of the exposure light EL2 that is irradiated onto the reticle R2. Note that, similarly to the exposure light EL1, the exposure light EL2 is formed into a slit extending in the X direction by a variable field stop (not shown) included in the illumination optical system ILS before entering the correction lens 42b. The reflection mirror 43b is disposed above the reticle stage RST2, and deflects the exposure light EL2 transmitted through the correction lens 42b downward (−Z direction).

  In the present embodiment, it is assumed that the exposure light EL1 emitted from the exposure light source LS1 and the exposure light EL2 emitted from the exposure light source LS2 have different polarization states. For example, it is assumed that the exposure light EL1 is s-polarized light and the exposure light EL2 is p-polarized light. Further, in the present embodiment, an example in which two exposure light sources LS1 and LS2 that emit exposure light EL1 and EL2 having different polarization states are provided will be described. For example, exposure light in a random polarization state is emitted. The exposure light EL1, EL2 may be generated as a configuration including one exposure light source and a polarization beam splitter.

  The reticle individual optical system 41 includes reticle individual imaging optical systems 44 a and 44 b, reflection mirrors 45 a and 45 b, a reflection mirror 46, and a polarization beam splitter 47. The reticle individual imaging optical system 44a is disposed below the reticle stage RST1, and corrects the shape of the slit-shaped exposure light EL1 that has passed through the reticle R1. The reflection mirror 45a is disposed below the reticle individual imaging optical system 44a, and deflects the exposure light EL1 that passes through the reticle individual imaging optical system 44a in the + Y direction. The reticle individual imaging optical system 44b is disposed below the reticle stage RST2, and corrects the shape of the slit-shaped exposure light EL2 transmitted through the reticle R2. The reflection mirror 45b is disposed below the reticle individual imaging optical system 44b, and deflects the exposure light EL2 that passes through the reticle individual imaging optical system 44b in the -Y direction.

  The reflection mirror 46 is disposed above the polarization beam splitter 47 and in the −Y direction of the reflection mirror 45b, and deflects the exposure light EL1 reflected in the −Y direction by the reflection mirror 45b in the −Z direction. The polarization beam splitter 47 is disposed on the optical axis AX above the projection optical system PL and in the + Y direction of the reflection mirror 45b. The polarization beam splitter 47 transmits the exposure light EL1 deflected in the −Z direction by the reflection mirror 46 and deflects the exposure light EL2 deflected in the + Y direction by the reflection mirror 45b in the −Z direction. With the above-described reticle individual optical system 41, it is possible to individually correct the imaging system for each illumination region set on the reticles R1 and R2. Further, here, without using the polarization beam splitter 47, the reflected light from the reflecting mirrors 45a and 45b is individually incident with a slight shift from the optical axis of the projection optical system PL, and the exposure slit is formed on the wafer surface. It may be separated with.

  The focal position on the object side of the projection optical system PL and the illumination area on the reticles R 1 and R 2 may be optically conjugated by the reticle individual optical system 41. As shown in FIG. 2, the surface of the wafer W is disposed at the focal position on the image side of the projection optical system PL. Therefore, the illumination area on reticles R1 and R2 is conjugate with the surface of wafer W with respect to projection optical system PL. In the present embodiment, an ArF excimer laser (wavelength 193 nm) is provided as the exposure light sources LS1 and LS2. Further, as the liquid Lq supplied between the projection optical system PL and the wafer W, pure water that absorbs less ArF excimer laser light is used.

  In FIG. 2, the reticle R1 is held on the reticle stage RST1, and the reticle R2 is held on the reticle stage RST2, but the same kind of reticle (on the reticle stages RST1 and RST2 ( Reticles on which the same pattern is formed may be held, or different types of reticles (reticles on which different patterns are formed) may be held. Details of the reticles held on these reticle stages RST1 and RST2 will be described later.

  Returning to FIG. 1, reticle stage RST (RST 1, RST 2) is supported on upper step 2 a of main column 2. An opening 5a through which a pattern image of reticle R (reticles R1, R2) passes is formed at the center of reticle stage RST. A reticle surface plate 5c is supported on the upper step 2a of the main column 2 via a vibration isolation unit 5b. An opening 5d through which the pattern image of the reticle R passes is also formed at the center of the reticle surface plate 5c. A plurality of gas bearings (air bearings) 5e that are non-contact bearings are provided on the lower surface of the reticle stage RST.

  Reticle stage RST is supported in a non-contact manner on the upper surface (guide surface) of reticle surface plate 5c by air bearing 5e, and is a plane perpendicular to optical axis AX of projection optical system PL by a mask stage driving mechanism such as a linear motor. In other words, it can move two-dimensionally in the XY plane and can rotate in the θZ direction. A movable mirror 5f is provided on the reticle stage RST. A laser interferometer 5g is provided at a position facing the movable mirror 5f. The position of the reticle R on the reticle stage RST in the two-dimensional direction and the rotation angle in the θZ direction (including rotation angles in the θX and θY directions in some cases) are measured in real time by the laser interferometer 5g, and the measurement result is the main control. It is output to the system MC. The main control system MC controls the position of the reticle R supported by the reticle stage RST by driving the mask stage driving mechanism based on the measurement result of the laser interferometer 5g.

  The projection optical system PL projects the pattern image of the reticle R (reticles R1, R2) onto the wafer W at a predetermined projection magnification β, and is an optical element (lens) provided at the front end portion on the wafer W side. A plurality of optical elements including 1 are supported by a lens barrel PK. In the present embodiment, the projection optical system PL is a reduction system having a projection magnification β of, for example, 1/4 or 1/5. Note that the projection optical system PL may be either an equal magnification system or an enlargement system. A flange portion FLG is provided on the outer peripheral portion of the lens barrel PK. A lens barrel surface plate 7 is supported on the lower step 2 b of the main column 2 via a vibration isolation unit 6. The projection optical system PL is supported by the lens barrel base plate 7 by engaging the flange portion FLG of the projection optical system PL with the lens barrel base plate 7. In the present embodiment, it is assumed that the projection optical system PL projects an inverted image of the pattern formed on the reticle R onto the wafer W.

The optical element 1 provided at the tip of the projection optical system PL is detachably attached to the lens barrel PK. The optical element 1 with which the liquid Lq in the immersion area WR comes into contact is formed of meteorite (calcium fluoride: CaF ₂ ). Since meteorite has high affinity with water, the liquid Lq can be brought into close contact with almost the entire liquid contact surface of the optical element 1. Thereby, the optical path of the exposure light EL between the optical element 1 and the wafer W can be reliably filled with the liquid Lq. The optical element 1 may be quartz having high affinity with pure water. Further, the liquid contact surface of the optical element 1 may be subjected to a hydrophilization (lyophilic process) to further increase the affinity with the liquid Lq.

  A plate member 8 is provided around the optical element 1 so as to surround the optical element 1. The plate member 8 is provided in order to satisfactorily form the liquid immersion region WR over a wide range, and the surface (that is, the lower surface) facing the wafer W is a flat surface. The lower surface (liquid contact surface) of the optical element 1 provided at the distal end portion of the projection optical system PL is also a flat surface, and is arranged so that the lower surface of the plate member 8 and the lower surface of the optical element 1 are substantially flush. . Similar to the optical element 1, the lower surface of the plate member 8 can be subjected to surface treatment (lyophilic treatment).

  Wafer stage WST is configured to be movable while adsorbing and holding wafer W via substrate holder 9, and a plurality of gas bearings (air bearings) 10 which are non-contact bearings are provided on the lower surface thereof. A substrate surface plate 12 is supported on the base plate 3 via a vibration isolation unit 11. Air bearing 10 has an air outlet that blows out gas (air) to the upper surface (guide surface) of substrate surface plate 12, and an air inlet that sucks gas between the lower surface of wafer stage WST (bearing surface) and the guide surface. And a constant gap is maintained between the lower surface of wafer stage WST and the guide surface by a balance between the repulsive force caused by blowing out the gas from the blower outlet and the suction force caused by the intake port.

  That is, wafer stage WST is supported in a non-contact manner on the upper surface (guide surface) of substrate surface plate (base member) 12 by air bearing 10, and light from projection optical system PL is received by a substrate stage drive mechanism such as a linear motor. It can move two-dimensionally in a plane perpendicular to the axis AX, that is, in the XY plane, and can rotate in the θZ direction. Further, the substrate holder 9 is provided so as to be movable in the Z-axis direction, the θX direction, and the θY direction with respect to the wafer stage WST. The substrate stage drive mechanism is controlled by the main control system MC. That is, the main control system MC controls the substrate holder 9 via the substrate stage drive mechanism, controls the focus position (Z position) and the tilt angle of the wafer W, and controls the surface of the wafer W by the autofocus method and autoleveling. To match the image plane of the projection optical system PL.

  A movable mirror 13 is provided on wafer stage WST (substrate holder 9), and a laser interferometer 14 is provided at a position facing movable mirror 13. The two-dimensional position and rotation angle of wafer W on wafer stage WST are measured in real time by laser interferometer 14, and the measurement result is output to main control system MC. The main control system MC positions the wafer W supported by the wafer stage WST by driving a substrate stage driving mechanism including a linear motor based on the measurement result of the laser interferometer 14.

  An auxiliary plate 15 is provided on wafer stage WST (substrate holder 9) so as to surround wafer W. The auxiliary plate 15 has a flat surface substantially the same height as the surface of the wafer W held by the substrate holder 9. By providing the auxiliary plate 15, even when the edge region of the wafer W is exposed, the liquid Lq is held under the projection optical system PL by the auxiliary plate 15 and the wafer W. Further, a recovery port 16 connected to a recovery device (not shown) that recovers the liquid Lq that has flowed out of the wafer W is provided outside the auxiliary plate 15 on the upper surface of the substrate holder 9. The recovery port 16 is an annular groove formed so as to surround the auxiliary plate 15, and a liquid absorbing member made of a sponge-like member, a porous body, or the like is disposed therein.

  Wafer stage WST is supported by X guide stage 17 so as to be movable in the X-axis direction. Wafer stage WST is movable with a predetermined stroke in the X-axis direction by X linear motor 18 while being guided by X guide stage 17. At both ends of the X guide stage 17 in the longitudinal direction, a pair of Y linear motors 19 capable of moving the X guide stage 17 along with the wafer stage WST in the Y axis direction are provided. A gas bearing (air bearing) that is a non-contact bearing is interposed between the stator of the Y linear motor 19 and the flat portion of the guide portion 20, and the stator of the Y linear motor 19 is guided by the air bearing. It is supported in a non-contact manner with respect to the flat portion.

  Further, on both sides of the substrate surface plate 12 in the X-axis direction, guide portions 20 that are formed in an L shape in front view and guide the movement of the X guide stage 17 in the Y-axis direction are provided. The guide part 20 is supported on the base plate 3. On the other hand, a concave guided member 21 is provided at each of both longitudinal ends of the lower surface of the X guide stage 17. The guide portion 20 is engaged with the guided member 21 and is provided so that the upper surface (guide surface) of the guide portion 20 and the inner surface of the guided member 21 face each other. A gas bearing (air bearing), which is a non-contact bearing, is provided on the guide surface of the guide portion 20, and the X guide stage 17 is supported in a non-contact manner with respect to the guide surface.

  The liquid supply mechanism SW supplies the liquid Lq between the projection optical system PL and the wafer W, and includes an ultrapure water production apparatus 30, a temperature adjustment apparatus 31, and a supply nozzle 32. The ultrapure water production apparatus 30 is an apparatus that produces ultrapure water with high purity. The temperature control device 31 includes a temperature control unit that controls the temperature of the ultrapure water produced by the ultrapure water production device 30 at a constant level, a deaeration unit that degass the ultrapure water, and temperature control and deaerated ultrapure water And a pressure pump for delivering ultrapure water. The supply nozzle 32 is disposed close to the surface of the wafer W and is connected to the temperature adjustment device 31 via the supply pipe 33, and the ultrapure water delivered from the temperature adjustment device 31 is projected as the liquid Lq. It is supplied between the optical system PL and the wafer W.

  In the middle of the supply pipe 33, a flow meter 34 for measuring the amount of liquid Lq (liquid supply amount per unit time) supplied from the temperature adjustment device 31 onto the wafer W is provided. The flow meter 34 monitors the amount of the liquid Lq supplied onto the wafer W and outputs the measurement result to the main control system MC. The main control system MC controls the liquid supply operation of the temperature control device 31 according to the monitoring result of the flow meter 34, and controls the supply amount of the liquid Lq per unit time supplied between the projection optical system PL and the wafer W. To do. A valve (not shown) for opening and closing the flow path of the supply pipe 33 is provided between the flow meter 34 and the supply nozzle 32 in the supply pipe 33. The opening / closing operation of the valve is controlled by the main control system MC.

  The liquid recovery mechanism CW recovers the liquid Lq on the wafer W (or the substrate holder 9) supplied by the liquid supply mechanism SW, and includes a recovery nozzle 35, a vacuum system 36, a flow meter 37, and a recovery tank. 38 etc. are comprised. The recovery nozzle 35 is disposed close to the surface of the wafer W and is connected to a recovery tank 38 via a recovery tube 39. The vacuum system 36 includes a vacuum pump, and its operation is controlled by the main control system MC. When the vacuum system 36 is driven, the liquid Lq on the wafer W is recovered through the recovery nozzle 35.

  The liquid Lq recovered by the recovery nozzle 35 is guided to the recovery tank 38 via the recovery pipe 39. In the middle of the recovery pipe 39, a flow meter 37 for measuring the amount of the recovered liquid Lq (liquid recovery amount per unit time) is provided. The flow meter 37 monitors the amount of the liquid Lq collected from the wafer W through the collection nozzle 35, and outputs the measurement result to the main control system MC. The main control system MC controls the operation of the vacuum system 36 according to the monitoring result of the flow meter 37, and controls the recovery amount per unit time of the liquid Lq recovered from between the projection optical system PL and the wafer W.

  The recovery tank 38 temporarily stores the liquid Lq recovered via the recovery nozzle 35, and a discharge pipe for discharging the stored liquid Lq is provided at the bottom of the recovery tank 38. The liquid Lq discharged from the discharge pipe is discarded or cleaned, for example, and returned to the ultrapure water production apparatus 30 or the like for reuse.

  As shown in the partial sectional view of FIG. 1, the liquid supply mechanism SW and the liquid recovery mechanism CW are separated and supported with respect to the lens barrel surface plate 7. Thereby, the vibration generated by the liquid supply mechanism SW and the liquid recovery mechanism CW is not transmitted to the projection optical system PL via the lens barrel surface plate 7.

  The main control system MC performs overall exposure processing of the exposure apparatus EX to perform exposure processing of the wafer W. As described above, the exposure apparatus EX of the present embodiment is a scanning type exposure apparatus that transfers the pattern formed on the reticle R to the wafer W while moving the reticle R and the wafer W synchronously. A plurality of exposure control methods) are prepared. Specifically, the main control system MC performs the first operation while reversing the moving direction of the wafer stage WST every time the pattern of the reticle R is transferred to each of the shot areas (partition areas) set on the wafer W. The exposure control method and a second method in which the pattern of the reticle R is continuously transferred to a plurality of adjacent shot areas on the wafer W while moving the wafer stage WST in a certain direction without reversing the moving direction of the wafer stage WST. Exposure control methods are prepared, and these exposure control methods can be switched.

  FIG. 3 is a diagram for explaining the first exposure control and the second exposure control performed by the main control system MC. FIG. 3A is a diagram showing the movement trajectory of the wafer W during the first exposure control. (B) is a diagram showing a movement locus of the wafer W during the second exposure control. As shown in FIG. 3, it is assumed that a plurality of shot areas SA1 to SAn (n is an integer of 2 or more) are arranged on the wafer W in the X direction and the Y direction. In FIG. 3, the maximum number of shot areas in the X direction (non-scanning direction) is set to 6 and the maximum number of shot areas in the Y direction (scanning direction) is set to 4 for simplicity of explanation. 3 indicates a trajectory through which the exposure slit (the exposure area on the wafer W on which the pattern of the reticle R is projected) passes on the wafer W, and the broken line indicates the exposure of one shot area. The movement trajectory at the time of the stepping movement of wafer stage WST performed to expose the next shot area after completion is shown.

  In the example shown in FIG. 3A, the vicinity of the + Y side end of the shot area SA3 on the wafer W is set to the exposure start position ST, and the vicinity of the + Y side end of the shot area SA6 is set to the exposure end position EN. Has been. The pattern of the reticle R is transferred to all shot areas from the exposure start position ST to the exposure end position EN. As shown in FIG. 3A, in the first exposure control, the shot area Each time the pattern of the reticle R is transferred to each of these, the moving direction of the wafer stage WST (the method of moving the exposure slit) is reversed.

  On the other hand, in the example shown in FIG. 3B, the vicinity of the + Y side end of the shot area SA1 on the wafer W is set to the exposure start position ST, and the vicinity of the + Y side end of the shot area SAn-1 is set. The exposure end position EN is set. In the second exposure control, as in the first exposure control, the pattern of the reticle R is transferred to all shot areas from the exposure start position ST to the exposure end position EN. ), In the second exposure control, the reticle R is continuously applied to a plurality of adjacent shot regions on the wafer W while moving the wafer stage WST in a certain direction without reversing the moving direction of the wafer stage WST. The pattern is transferred. For example, the pattern of the reticle R is continuously transferred to the shot areas SA1 and SA2, and then the shot areas SA6, SA5, SA4, and SA3 after the moving direction of the wafer stage WST (moving direction of the exposure slit) is reversed. On the other hand, the pattern of the reticle R is continuously transferred.

  Further, when performing the first exposure control, the main control system MC holds the reticle R1 shown in FIG. 2 on the reticle stage RST1, and holds the reticle R2 different from the reticle R1 on the reticle RST2. Then, control is performed to transfer the pattern formed on the reticle R1 and the pattern formed on the reticle R2 to each of the shot areas almost simultaneously. That is, in the first exposure control, simultaneous double exposure of the pattern is performed while the moving direction of wafer stage WST is reversed for each shot area.

  Here, the simultaneous double exposure performed by the first exposure control will be described in detail. 4 and 5 are diagrams for explaining the movement of the reticle and the wafer when simultaneous double exposure is performed by the first exposure control. As shown in FIGS. 4 and 5, the reticle R1 on which the pattern P1 having the shape of the letter “A” is formed is held on the reticle stage RST1, and the shape of the letter “B” is held on the reticle stage RST2. It is assumed that reticle R2 on which a certain pattern P2 is formed is held.

  When performing simultaneous double exposure in the first exposure control, it is necessary to superimpose the image of the pattern P1 formed on the reticle R1 and the image of the pattern P2 formed on the reticle R2, so that the main control system MC Then, control is performed to synchronously move reticle stage RST1 and reticle stage RST2 in the same direction. That is, when the reticle stage RST1 is moved in the + Y direction, the reticle stage RST2 is also moved in the + Y direction in synchronization with the reticle stage RST1, and when the reticle stage RST1 is moved in the -Y direction, In synchronization with reticle stage RST1, reticle stage RST2 is also controlled to move in the -Y direction.

  Specifically, consider a case where the shot areas SA7 and SA11 adjacent in the X direction on the wafer W are sequentially double-exposed by the first exposure control. As shown in FIG. 4, when the shot area SA7 is subjected to simultaneous double exposure, the reticles R1 and R2 are moved in the + Y direction and the wafer W is moved in the -Y direction. Then, after the reticles R1, R2 and the wafer W are synchronized, the illumination area IA1 on the reticle R1 is illuminated with the exposure light EL1, and the illumination area IA2 on the reticle R2 is illuminated with the exposure light EL2, as shown in FIG. ), The transfer of the patterns P1 and P2 is started.

  Here, by the reticle individual optical system 41 shown in FIG. 2, the image of the pattern P1 formed on the reticle R1 and the image of the pattern P2 formed on the reticle R2 are exposed on the wafer W (on the shot area SA7). Projected to overlap SL. Note that an inverted image of the patterns P1 and P2 is projected onto the wafer W by the projection optical system PL. As the reticles R1 and R2 move in the + Y direction and the wafer W moves in the -Y direction, the patterns P1 and P2 are sequentially transferred onto the shot area SA7. Then, as shown in FIG. 4B, the entire surface of the reticle R1 (the entire surface of the pattern formation region on which the pattern P1 is formed) crosses the illumination region IA1 (the illumination region IA1 scans the entire surface of the pattern formation region). When the entire surface of the reticle R2 (the entire surface of the pattern formation region on which the pattern P2 is formed) crosses the illumination region IA2 (the illumination region IA2 scans the entire surface of the pattern formation region), the simultaneous double exposure of the shot region SA7 is completed.

  Next, when simultaneous double exposure is performed on the shot area SA11, first, the wafer stage WST is stepped in the X direction, and the wafer W is moved in the -X direction. Next, the reticles R1 and R2 are moved in the −Y direction, and the wafer W is moved in the + Y direction. Then, after the reticles R1, R2 and the wafer W are synchronized, the illumination area IA1 on the reticle R1 is illuminated with the exposure light EL1, and the illumination area IA2 on the reticle R2 is illuminated with the exposure light EL2, as shown in FIG. ), The transfer of the patterns P1 and P2 is started. As the reticles R1 and R2 move in the -Y direction and the wafer W moves in the + Y direction, the patterns P1 and P2 are sequentially transferred onto the shot area SA11.

  Then, as shown in FIG. 5B, the entire surface of the reticle R1 (the entire surface of the pattern formation region on which the pattern P1 is formed) crosses the illumination region IA1 (the illumination region IA1 scans the entire surface of the pattern formation region). When the entire surface of the reticle R2 (the entire surface of the pattern formation region on which the pattern P2 is formed) crosses the illumination region IA2 (the illumination region IA2 scans the entire surface of the pattern formation region), the simultaneous double exposure of the shot region SA11 is completed. As described above, in the first exposure control, the pattern is transferred on both the forward path (moving path in the + Y direction) and the returning path (moving path in the -Y direction) of the reticle R.

  On the other hand, when performing the second exposure control, the main control system MC holds the reticle (for example, the reticle R1) on which the same pattern is formed on both the reticle stages RST1 and RST2, and holds the wafer W. After the reticle pattern is transferred to all the upper shot areas, the reticle is exchanged to hold a reticle (for example, reticle R2) in which a pattern different from the previous reticle is formed on both reticle stages RST1 and RST2. The reticle pattern is transferred to all shot areas on the wafer W. Alternatively, the reverse control, that is, the control of transferring the pattern of the reticle R1 after the pattern of the reticle R2 is transferred.

  That is, after a pattern is transferred to all shot areas on the wafer W by transferring the pattern to a plurality of adjacent shot areas without reversing the moving direction of wafer stage WST, the same method is used first. Double exposure is performed by transferring a pattern different from the transferred pattern to all of the shot areas. The pattern transfer order may be such that the pattern of reticle R2 is transferred after the pattern of reticle R1 is transferred, or the pattern of reticle R1 may be transferred after the pattern of reticle R2 is transferred. Further, the pattern transfer order may be changed for each wafer W.

  Here, the second exposure control will be described in detail. 6 to 8 are diagrams for explaining the movement of the reticle and the wafer when exposure is performed by the second exposure control. As shown in FIGS. 6 to 8, reticle R1 on which pattern P1 having the shape of the letter “A” is formed is held on reticle stage RST1, and the same as pattern P1 of reticle R1 is held on reticle stage RST2. It is assumed that reticle R3 on which pattern P1 is formed is held.

  Here, in the second exposure control, since it is necessary to expose a plurality of shot areas with the wafer W moved in one direction, both in the forward path and the return path of the reticle stage RST1 as in the first exposure control. The pattern cannot be transferred. Therefore, for example, when the pattern of the reticle R1 on the reticle stage RST1 is transferred to one shot area on the forward path of the reticle stage RST1, when transferring the pattern to the next shot area, the reticle is transferred on the forward path of the reticle stage RST2. It is necessary to transfer the pattern of reticle R3 on stage RST2. Therefore, the main control system MC performs control to synchronize the reticle stage RST1 and the reticle stage RST2 and move them in opposite directions.

  Specifically, consider a case where the shot areas SA6, SA5, and SA4 adjacent in the Y direction on the wafer W are sequentially exposed by the second exposure control. As shown in FIG. 6, when the shot area SA6 is exposed, the reticle R1 is moved in the + Y direction and the wafer W is moved in the -Y direction. Then, after the reticle R1 and the wafer W are synchronized, the illumination area IA1 on the reticle R1 is illuminated with the exposure light EL1, and the transfer of the pattern P1 is started as shown in FIG. 6A. Here, the illumination light EL2 is not illuminated on the illumination area IA2 on the reticle R3.

  The image of the pattern P1 formed on the reticle R1 is projected onto the exposure slit SL on the wafer W (on the shot area SA6). Note that an inverted image of the pattern P1 is projected onto the wafer W by the projection optical system PL. As the reticle R1 moves in the + Y direction and the wafer W moves in the -Y direction, the pattern P1 is sequentially transferred onto the shot area SA6. Then, as shown in FIG. 6B, the entire surface of the reticle R1 (the entire surface of the pattern formation region on which the pattern P1 is formed) crosses the illumination region IA1 (the illumination region IA1 scans the entire surface of the pattern formation region). The exposure of the area SA6 is finished. In the second exposure control, even if the exposure of the shot area SA6 is completed, the moving direction of the wafer W is not reversed and the wafer W is continuously moved in the −Y direction at the same speed.

  Next, the reticle R3 is moved in the + Y direction, and after the reticle R3 and the wafer W are synchronized, the illumination area IA2 on the reticle R3 is illuminated with the exposure light EL2, and as shown in FIG. Transfer of the pattern P1 formed on R3 to the shot area SA5 is started. Since shot area SA6 and shot area SA5 are adjacent to each other, reticle stage RST2 prior to the end of exposure of shot area SA6 so that exposure of shot area SA5 can be performed immediately after the exposure of shot area SA6 is completed. Start accelerating. Further, during exposure of the shot area SA5, irradiation of the exposure light EL1 to the reticle R1 is stopped.

  As the reticle R3 moves in the + Y direction and the wafer W moves in the -Y direction, the pattern P1 is sequentially transferred onto the shot area SA5. Here, during the exposure of the shot area SA5, the reticle R1 is moved in the -Y direction. This is because the wafer W continues to move in the -Y direction during exposure of the shot areas SA6, SA5, and SA4, and exposure is possible on the forward path of the reticle R1, but exposure cannot be performed on the return path. This is because it is necessary to return to the initial position (the starting point of the outward path). Then, as shown in FIG. 7B, the entire surface of the reticle R3 (the entire surface of the pattern formation region on which the pattern P1 is formed) crosses the illumination region IA2 (the illumination region IA2 scans the entire surface of the pattern formation region). The exposure of the area SA5 is finished. Even if the exposure of the shot area SA5 is completed, the moving direction of the wafer W is not reversed and the wafer W is continuously moved in the -Y direction at the same speed.

  Next, the reticle R1 is moved again in the + Y direction, and after the reticle R1 and the wafer W are synchronized, the illumination area IA1 on the reticle R1 is illuminated with the exposure light EL1, and as shown in FIG. Transfer of the pattern P1 formed on the reticle R1 to the shot area SA4 is started. Note that acceleration of reticle stage RST1 is started prior to the end of exposure of shot area SA65 so that exposure of shot area SA4 can be performed immediately after the exposure of shot area SA5 is completed. Further, during exposure of the shot area SA4, irradiation of the exposure light EL2 to the reticle R3 is stopped.

  As the reticle R1 moves in the + Y direction and the wafer W moves in the -Y direction, the pattern P1 is sequentially transferred onto the shot area SA4. Here, during the exposure of the shot area SA4, the reticle R3 is moved in the -Y direction. This is because the reticle R3 can also be exposed on the forward path, but cannot be exposed on the return path, so the reticle R3 needs to be returned to the initial position (starting point of the forward path). Then, as shown in FIG. 8B, a shot is made when the entire surface of the reticle R1 (the entire surface of the pattern formation region on which the pattern P1 is formed) crosses the illumination region IA1 (the illumination region IA1 scans the entire surface of the pattern formation region). The exposure of the area SA4 ends.

  Thus, in the second exposure control, while the pattern is transferred on the forward path of one reticle stage (for example, reticle stage RST1), the other stage (for example, reticle stage RST2) is moved to the initial position via the return path. While the pattern is being transferred on the forward path of the other reticle stage, control is performed to return one stage to the initial position via the backward path, and on the forward path (moving path in the + Y direction) of reticles R1 and R3. Only the pattern is transferred. In order to perform double exposure in the second exposure control, after transferring one pattern (for example, the pattern P1) by performing the above control, the reticle on the reticle stage RST1, RST2) is exchanged. Then, the same control as described above is performed to transfer another pattern (for example, pattern P2).

  In addition, the main control system MC calculates an exposure time calculation unit that calculates a time required to expose the wafer W by performing the first exposure control and a time required to expose the wafer W by performing the second exposure control, respectively. 25. In exposure processing of wafer W, reticle stage RST and wafer stage WST are accelerated until they reach a constant speed, and after acceleration, the vibrations of reticle stage RST and wafer stage WST are converged to scan at a constant speed, and thereafter reticle stage RST. The operation of decelerating wafer stage WST is repeated.

  FIG. 9 is a graph showing an example of a change in the moving speed of wafer stage WST during exposure. FIG. 9 illustrates the change in the moving speed of wafer stage WST when the first exposure control described above, that is, the control of reversing the moving direction of wafer stage WST every time the exposure process is performed for each shot area. ing. Further, only the speed change when moving in the scanning direction (Y direction) is shown, and the non-scanning direction (X direction) is not shown.

  As shown in FIG. 9, when performing the exposure process while moving wafer stage WST in the + Y direction, wafer stage WST is accelerated in the + Y direction (acceleration period T1), and after a certain settling period T2 has passed, reticle R Scanning is performed to transfer the pattern to the shot area (scanning period T3). Then, after the scanning period T3 has elapsed, wafer stage WST is decelerated and stopped (deceleration period T4). When exposure of one shot area is completed, wafer stage WST moves stepwise in the X direction (step movement period T5). Subsequently, the exposure process is performed while the wafer stage WST is moved in the −Y direction. The wafer stage WST shows the same speed change as when moving in the + Y direction only in the opposite direction.

Wafer stage WST acceleration period T1, settling period T2, scanning period T3, and deceleration period T4 are substantially the same regardless of whether the first exposure control or the second exposure control described above is performed. For this reason, the exposure time calculation unit 25 calculates the time required to expose the wafer W by the first exposure control and the second exposure control using each of the above periods. In the first exposure control, since acceleration / deceleration is performed for each shot area, the time Ta required to expose the wafer W having the layout shown in FIG. 3A is approximately expressed by the following equation (1). . In the following equation (1), it is assumed that the number of shot areas is n and that the lengths of all the step movement periods T5 are the same.
Ta = (T1 + T2 + T3 + T4) × n + T5 × (n−1) (1)

On the other hand, in the second exposure control, since acceleration / deceleration of wafer stage WST is omitted in the adjacent shot region, time Tb required to expose wafer W having the layout shown in FIG. It is represented by the following formula (2). In the following formula (2), it is assumed that the number of shot areas is n, the number of rows in the shot area is i, the number of columns in the shot area is j, and the length of all the step movement periods T5 is the same. is doing.
Tb = (T1 + T2 + T4) × j + T5 (j−1) + T3 × n (2)
The above formulas (1) and (2) are formulas for calculating the time required for exposure when the layout of the wafer W is the layout shown in FIG. 3, and are used for all layouts. Note that this is not a general formula that can be made.

Here, when performing the first exposure control, simultaneous double exposure can be performed by using the reticles R1 and R2 on the reticle stages RST1 and RST2. However, since the simultaneous double exposure cannot be performed in the second exposure control, for example, after the pattern of the reticle R1 held on the reticle stages RST1 and RST2 is transferred to all shot areas on the wafer W, It is necessary to exchange the reticle R1 held on the stage together with the reticle R2 and transfer the pattern of the reticle R2 to the entire shot area on the wafer W. Therefore, the time Tc required for double exposure of the wafer W by the second exposure control is approximately expressed by the following equation (3). In the following formula (3), the time required for exchanging the reticle (reticle exchange time) is T6.
Tc = Tb × 2 + T6 (3)

  For example, an acceleration period T1 and a deceleration period T4 are set to 100 msec, a settling period T2 is set to 15 msec, a scanning period T3 is set to 60 msec, a stepping period T5 is set to 0 msec, a reticle exchange time T6 is set to 6 seconds, and 100 shots (n = 100) are performed on a 300 mm wafer. = 9, j = 15, Ta≈27.5 sec is obtained from the above equation (1), Tb≈9.2 sec is obtained from the above equation (2), and Tc≈24.5 sec from the above equation (3). Is required. The exposure time calculation unit 25 performs such calculation and calculates the time required to expose the wafer W by the first and second exposure controls. Here, the above stepping period T5 is assumed to be included in the deceleration period T4 and the acceleration period T1 in parallel operation, and is set to 0 msec.

  In the above example, the time Tb required for exposing the wafer W by the second exposure control is about 33% of the time Ta required for double exposure of the wafer W by the first exposure control. Therefore, the total time (Tb × 2) required only for double exposure by transferring the pattern of the reticle R1 and the pattern of the reticle R2 onto the wafer W by the second exposure control is the wafer by the first exposure control. This is about 67% of the time Ta required for double exposure of W.

  Here, when double exposure is performed by the second exposure control, the reticle needs to be replaced. Therefore, the time Tc required for double exposure of the wafer W by the second exposure control is determined by the first exposure control. This is about 89% of the time Ta required for double exposure of W. Therefore, it can be seen that performing double exposure by the second exposure control is advantageous from the viewpoint of throughput. As the number of shots increases, it is more advantageous to perform the second exposure control.

  Next, an exposure method for transferring the pattern of the reticle R onto the wafer W using the exposure apparatus EX configured as described above will be described. In the following description, an exposure method for double exposure of the patterns (patterns P1, P2) of the reticle R1 and the reticle R2 will be described as an example. FIG. 10 is a flowchart showing an exposure method according to an embodiment of the present invention. When the exposure process is started, the main control system MC first reads an exposure recipe (control command group that defines the operation of the exposure apparatus) stored in advance (step S11). This recipe includes information indicating the layout of the shot area on the wafer W. Here, in order to calculate the time required for exposure from the above equations (1) to (3), in addition to information indicating the layout of the shot area, information indicating the acceleration of the reticle stage RST and wafer stage WST is required. These are also stored in the main control system MC in advance.

  Next, the exposure time calculation unit 25 of the exposure apparatus MC includes information indicating the layout of the shot area on the wafer W included in the read recipe, and the reticle stage RST and wafer stage WST stored in advance in the main control system MC. Using the information indicating the acceleration and the like, the time required for exposure is calculated by the first exposure control and the second exposure control from the above-described equations (1) to (3) (step S12). Next, the main control system MC determines whether to perform exposure control by the first exposure control based on the calculation result of the exposure time calculation unit 25 (step S13). Here, for example, when the time required for exposure by the first exposure control is shorter than the time required for exposure by the second exposure control, the determination result is “YES”.

  If the determination result in step S13 is “YES”, the main control system MC controls a reticle loader (reticle transfer device) (not shown) to hold the reticle R1 on the reticle stage RST1 and also to the reticle R2. Is held on reticle stage RST2 (step S14). On the other hand, if the determination result in step S13 is “NO”, the main control system MC controls the reticle loader to hold the reticle R1 on the reticle stage RST1, and the same pattern as the reticle R1. The reticle R3 on which P1 is formed is held on the reticle stage RST2 (step S15).

  Next, wafer W is loaded onto wafer stage WST (step S16). In order to improve throughput, it is desirable to load the reticle (steps S14 and S15) and load the wafer W in parallel. Next, EGA (enhanced global alignment) measurement is performed (step S17). Here, the EGA measurement refers to position information of marks (alignment marks) formed on each of a part of typical (for example, 3 to 9) shot areas preset on the wafer W. The calculation method is to determine the regularity of the arrangement of all shot areas set on the wafer W based on the design information by a statistical method. Specifically, position information of several representative marks formed on the wafer W loaded on the wafer stage WST is measured using an alignment sensor, and the main control system MC performs EGA calculation based on the measurement result. To determine the regularity of the arrangement of all shot areas set on the wafer W.

  Next, the main control system MC outputs a control signal to the temperature control device 31 provided in the liquid supply mechanism SW to make the temperature of the ultrapure water produced by the ultrapure water production device 30 constant, Ultrapure water with a constant temperature is delivered at a predetermined rate per unit time. The ultrapure water delivered from the temperature control device 31 is supplied as a liquid Lq between the optical element 1 provided at the tip of the projection optical system PL and the wafer W via the supply pipe 33 and the supply nozzle 32. Further, the main control system MC drives the vacuum system 38 of the liquid recovery mechanism CW in accordance with the supply of the liquid Lq by the liquid supply mechanism SW, and a predetermined amount of the liquid Lq per unit time via the recovery nozzle 35 and the recovery pipe 39. Is recovered in the recovery tank 38. Thereby, an immersion region WR of the liquid Lq is formed between the optical element 1 at the tip of the projection optical system PL and the wafer W (step S18). Here, in order to form the liquid immersion region WR, the main control system MC, for example, sets the liquid supply mechanism SW so that the liquid supply amount on the wafer W and the liquid recovery amount from the wafer W are substantially the same. And the liquid recovery mechanism CW.

  The main control system MC drives the wafer stage WST and moves the wafer W stepwise to the first exposure start position in a state where a constant amount of liquid Lq is constantly supplied between the projection optical system PL and the wafer W. . Specifically, if the main control system MC determines in step S13 that exposure is to be executed by the first exposure control, the main control system MC arranges the vicinity of the exposure start position ST shown in FIG. 3A below the projection optical system PL. If it is determined in step S13 that the exposure is performed by the second exposure control, the vicinity of the exposure start position ST shown in FIG. 3B is arranged below the projection optical system PL. Then, the first exposure control or the second exposure control is performed to expose the shot areas in order from the exposure start position ST to the exposure end position EN shown in FIG. 3A or 3B (step S19). .

  In the case where a plurality of wafers W (for example, one lot of wafers) having the same layout are exposed by the first exposure control, steps S16 to S19 in FIG. 10 are repeated. That is, the pattern P1 of the reticle R1 and the pattern P2 of the reticle R2 are simultaneously double-exposed on each shot area of the plurality of wafers W by the first exposure control. On the other hand, when a plurality of wafers W having the same layout are exposed by the second exposure control, first, the pattern P1 formed on the reticles R1 and R3 is transferred to each shot area of the plurality of wafers W. Thereafter, the reticles on reticle stages RST1 and RST2 are replaced with reticles R2 and R4 (reticle R4 is a reticle in which the same pattern as pattern P2 formed on reticle R2 is formed), and these reticles R2 and R4 are exchanged. Double exposure is performed by transferring the pattern P <b> 2 formed in (1) to each shot region of the plurality of wafers W.

  As described above, in the present embodiment, the first exposure control performed while reversing the moving direction of wafer stage WST each time the pattern of reticle R is transferred to each shot area on wafer W, and the movement of the wafer stage The second exposure control for continuously transferring the pattern of the reticle R to a plurality of adjacent shot areas on the wafer W can be switched while moving the wafer stage in a certain direction without reversing the direction. Since the first exposure control and the second exposure control can be switched according to the exposure time required for the exposure according to the layout of the shot area set on the wafer W, the throughput and the exposure accuracy are improved. be able to.

  In the second exposure control described above, a plurality of shot areas arranged in the scanning direction (Y direction) are continuously exposed without changing the scanning direction of wafer stage WST. Therefore, the immersion region WR between the optical element 1 of the projection optical system PL and the wafer W can be stabilized, and the exposure accuracy can be improved. Further, for example, when the scanning direction is frequently changed, there is a possibility that bubbles may enter the liquid immersion region WR and cause defects. However, by using the second exposure control, the probability of occurrence of such defects can be increased. Can be reduced.

  In the above embodiment, the time required for the first exposure control and the time required for the second exposure control are respectively calculated according to the layout of the shot area on the wafer W, and a plurality of exposure controls with the shorter exposure time are performed. The case where a wafer (for example, one lot of wafers W) is exposed has been described as an example. However, when exposing a plurality of wafers W, switching between the first exposure control and the second exposure control may be performed for each wafer W or for each lot. That is, the main control system MC does not switch between the first exposure control and the second exposure control until the exposure of one wafer W starts and ends, or the exposure of the wafer W for one lot. Do not perform (prohibit) from starting to ending.

  Further, the first exposure control and the second exposure control may be switched between the start and end of exposure of one wafer W. For example, in the above-described embodiment, the case where each shot area on the wafer W is double-exposed has been described as an example. However, in the case of an odd multiple exposure more than triple exposure, in addition to simultaneous double exposure, be sure to Only one type of pattern needs to be transferred to each shot area. For this reason, for example, in the case of triple exposure, it is desirable that two types of patterns are first subjected to simultaneous double exposure on each shot region by first exposure control, and the third type of pattern is transferred by second exposure control.

  In the above embodiment, the wafer W is exposed using the reticle R1 (and reticle R3) on which the pattern P1 is formed and the reticle R2 (and reticle R4) on which the pattern P2 is formed. You may perform exposure using the reticle in which the pattern P1 and the 2nd pattern P2 were formed. In this case, it is necessary to provide a reticle stage (reticle stages RST3, RST4) for holding a reticle on which a plurality of patterns are formed instead of the reticle stages RST1, RST2.

  When exposure is performed using a reticle on which a plurality of patterns are formed, when performing the above-described first exposure control, for example, on the reticle pattern P1 held on the reticle stage RST3 and on the reticle stage RST4. Simultaneous double exposure is performed using the reticle pattern P2 held in step S2. Further, when performing the second exposure control, the reticle pattern P1 held on the reticle stage RST3 and the reticle pattern P1 held on the reticle stage RST4, or the reticle held on the reticle stage RST3. The wafer W is exposed using the pattern P2 and the reticle pattern P2 held on the reticle stage RST4.

  In the above-described embodiment, an immersion exposure apparatus that locally fills the space between the projection optical system PL and the wafer W with a liquid is employed. However, as disclosed in JP-A-6-124873. An immersion exposure apparatus for moving a stage holding a substrate to be exposed in the liquid tank, and a liquid tank having a predetermined depth on the stage as disclosed in JP-A-10-303114, The present invention can also be applied to an immersion exposure apparatus that holds a substrate therein. The present invention is not limited to an immersion exposure apparatus, and can also be applied to an exposure apparatus that does not use an immersion method.

  Further, the present invention separately mounts a substrate to be processed such as a wafer as disclosed in JP-A-10-163099, JP-A-10-214783, JP-T 2000-505958, and the like. The present invention can also be applied to a twin stage type exposure apparatus having two stages that can move independently in the XY directions.

  Next, an embodiment of a method of manufacturing a micro device using the exposure apparatus according to the embodiment of the present invention in a lithography process will be described. FIG. 11 is a flowchart showing an example of a manufacturing process of a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). As shown in FIG. 11, a microdevice such as a semiconductor device includes a step (S31) for designing a function / performance of the microdevice, a step (S32) for producing a mask (reticle) based on the design step, and a substrate (device substrate). Wafer), exposure processing step S34 for transferring the mask pattern onto the substrate by the exposure apparatus EX of the above-described embodiment, device assembly step (including dicing process, bonding process, and packaging process) S35, and inspection step S36. And so on.

It is a front view which shows schematic structure of the exposure apparatus by one Embodiment of this invention. It is a side view showing a reticle individual optical system that guides exposure light EL through illumination optical system ILS and reticle R to projection optical system PL provided in exposure apparatus EX according to an embodiment of the present invention. It is a figure for demonstrating the 1st exposure control and 2nd exposure control which main control system MC performs. It is a figure explaining the motion of a reticle and a wafer in the case of performing simultaneous double exposure by 1st exposure control. It is a figure explaining the motion of a reticle and a wafer in the case of performing simultaneous double exposure by 1st exposure control. It is a figure explaining the movement of a reticle and a wafer in the case of performing exposure by the second exposure control. It is a figure explaining the movement of a reticle and a wafer in the case of performing exposure by the second exposure control. It is a figure explaining the movement of a reticle and a wafer in the case of performing exposure by the second exposure control. It is a graph which shows an example of a change of movement speed of wafer stage WST at the time of exposure. 5 is a flowchart showing an exposure method according to an embodiment of the present invention. It is a flowchart which shows an example of the manufacturing process of a microdevice.

Explanation of symbols

25 exposure time calculation unit EX exposure apparatus MC main control system P1, P2 pattern R, R1, R2 reticle RST, RST1, RST2 reticle stage SA1 to SAn shot area W wafer WST wafer stage

Claims (19)

In an exposure apparatus comprising a substrate stage movable while holding a substrate, and transferring a pattern formed on the mask to a plurality of partitioned regions on the substrate while moving the mask and the substrate stage synchronously,
First exposure control performed while reversing the moving direction of the substrate stage each time the pattern of the mask is transferred to each of the partitioned areas on the substrate, and the substrate stage is moved without reversing the moving direction of the substrate stage. An exposure apparatus comprising: a control device capable of switching between second exposure control for continuously transferring the mask pattern to a plurality of adjacent divided regions on the substrate while moving in a certain direction. The control device, when performing the first exposure control, performs a control to transfer the first pattern and a second pattern different from the first pattern to each of the partition regions on the substrate,
When performing the second exposure control, one of the first pattern and the second pattern is transferred to each of the partitioned areas on the substrate, and the other pattern is transferred after the transfer of one of the patterns. The exposure apparatus according to claim 1, wherein control is performed to transfer to each of the partitioned areas on the substrate.   The control device includes an exposure time calculation unit that calculates the time required to expose the substrate by performing the first and second exposure controls, and based on the calculation result of the exposure time calculation unit, 3. An exposure apparatus according to claim 2, wherein the first and second exposure controls are switched.   The said control apparatus exposes the said board | substrate using either one, without switching between the said 1st exposure control and the said 2nd exposure control during a predetermined period. The exposure apparatus according to any one of the above.   The predetermined period is a period from the start of the transfer of the mask pattern to a plurality of partitioned regions on one substrate to the end of the transfer of the mask pattern to all of the plurality of partitioned regions on the one substrate. The exposure apparatus according to claim 4, wherein the exposure apparatus is provided.   The predetermined period is from the start of the transfer of the mask pattern to the plurality of partitioned regions of each of the predetermined number of substrates to the end of the transfer of the mask pattern to all of the plurality of partitioned regions of the predetermined number of substrates. The exposure apparatus according to claim 4, wherein the exposure period is a period.   From the start of the transfer of the mask pattern to a plurality of partitioned areas on one substrate to the end of the transfer of the mask pattern to all of the plurality of partitioned areas on the one substrate. The exposure apparatus according to any one of claims 1 to 3, wherein the first exposure control and the second exposure control can be switched in between. A first stage movable while holding a first mask on which the first pattern is formed or a second mask on which the second pattern is formed;
8. A second stage capable of holding and moving the first mask on which the first pattern is formed or the second mask on which the second pattern is formed. An exposure apparatus according to claim 1. The control device, when performing the first exposure control, holds the first mask on the first stage and holds the second mask on the second stage,
9. The exposure apparatus according to claim 8, wherein when performing the second exposure control, one of the first mask and the second mask is held by each of the first and second stages. A third stage movable while holding a third mask in which the first and second patterns are integrally formed;
The exposure apparatus according to any one of claims 2 to 7, further comprising a fourth stage that holds and moves the third mask. The control device, when performing the first exposure control, the first pattern formed on the third mask on the third stage and the first pattern formed on the third mask on the fourth stage. Exposure of the substrate using two patterns,
When performing the second exposure control, the first pattern formed on the third mask on the third stage and the first pattern formed on the third mask on the fourth stage are used. Or exposing the substrate using the second pattern formed on the third mask on the third stage and the second pattern formed on the third mask on the fourth stage. The exposure apparatus according to claim 10, wherein: In an exposure method for transferring a pattern formed on the mask to a plurality of partitioned regions on the substrate while synchronously moving the mask and the substrate,
A first exposure control performed by reversing the moving direction of the substrate each time the pattern of the mask is transferred to each of the partitioned areas on the substrate; An exposure method comprising: performing switching from one to the other of the second exposure control for continuously transferring the pattern of the mask to a plurality of adjacent divided areas on the substrate during the movement. In the first exposure control, the first pattern and a second pattern different from the first pattern are transferred to each of the partitioned areas on the substrate almost simultaneously,
In the second exposure control, one of the first pattern and the second pattern is transferred to each of the partition regions on the substrate, and the other pattern is transferred onto the substrate after the transfer of one of the patterns. The exposure method according to claim 12, wherein the exposure is performed on each of the partitioned areas. Calculating each of a time required for exposure of the substrate in the first exposure control and a time required for exposure of the substrate in the second exposure control;
14. The exposure method according to claim 13, wherein switching from one of the first exposure control and the second exposure control to the other is performed based on the calculation result.   The exposure method according to any one of claims 12 to 14, wherein switching from one of the first exposure control and the second exposure control to the other during a predetermined period is prohibited.   The predetermined period is a period from the start of transfer of the mask pattern to a plurality of partitioned areas on one substrate to the end of transfer of the mask pattern to all of the plurality of partitioned areas on the one substrate. The exposure method according to claim 15, wherein:   The predetermined period is from the start of the transfer of the mask pattern to the plurality of partitioned regions of each of the predetermined number of substrates to the end of the transfer of the mask pattern to all of the plurality of partitioned regions of the predetermined number of substrates. 16. The exposure method according to claim 15, wherein the exposure period is a period.   From the start of the transfer of the mask pattern to a plurality of partitioned areas on one substrate to the end of the transfer of the mask pattern to all of the plurality of partitioned areas on the one substrate. The exposure method according to any one of claims 12 to 14, wherein switching from one of the exposure control and the second exposure control to the other is executed. The process of exposing a device pattern on a board | substrate using the exposure apparatus as described in any one of Claims 1-11, or the exposure method as described in any one of Claims 12-18. A device manufacturing method comprising:

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