JP5428671B2 - Exposure method, device manufacturing method, and exposure system - Google Patents

Description

  The present invention relates to an exposure method, a device manufacturing method, and an exposure system, and more specifically, for example, an object such as a wafer in a lithography process for manufacturing an electronic device (microdevice) such as a semiconductor element or a liquid crystal display element. The present invention relates to an exposure method for forming a pattern on an object by exposure, a device manufacturing method using the exposure method, and an exposure system including an exposure apparatus that exposes an object by the exposure method.

  In the manufacturing process of electronic devices such as semiconductor elements and liquid crystal display elements, step-and-repeat projection exposure apparatuses (steppers) or step-and-scan projection exposure apparatuses (scanners) are mainly used. Yes.

  In this type of exposure apparatus, a reticle is irradiated by irradiating illumination light onto a wafer or a glass plate or the like (hereinafter collectively referred to as a wafer) coated with a sensitive agent (photoresist) via a reticle and a projection optical system. The pattern formed on the (mask) is transferred to each of a plurality of shot areas arranged on the wafer. In particular, in the case of a semiconductor element, since dozens of layers of patterns are formed on a wafer in a superimposed manner, high overlay accuracy (positioning accuracy) between the respective layers is required.

  Therefore, in the exposure process, in order to align the wafer (wafer alignment), in recent years, predetermined statistical calculation is performed using the detection result of the position information of some of the plurality of alignment marks, Alternatively, an enhanced global alignment (EGA) system that obtains wafer distortion (in-shot error) in a shot area with high accuracy in addition to the arrangement of shot areas is widely adopted (for example, Patent Document 1 and Patent Document 1). (See 2nd grade).

  However, during the exposure process (lot processing), the reticle (mask) is deformed by heat generated by absorbing the illumination light. In addition, since lots of wafers (one lot is 25 or 50) are continuously exposed using the same reticle (mask), the degree of deformation of the reticle (mask) increases each time the wafer is exposed. That is, the distortion of the projected image of the pattern is enlarged. Therefore, in the past, in addition to the above-mentioned EGA wafer alignment, the amount of illumination light applied to the reticle is used to predict thermal deformation of the reticle by a predetermined calculation. Adjustment of the distortion of the projection optical system has been performed. However, the overlay accuracy required for the exposure apparatus becomes strict as semiconductor elements are highly integrated, and now it is becoming difficult to ensure sufficient overlay accuracy (positioning accuracy) even by the above-described predictive control.

US Pat. No. 4,780,617 US Pat. No. 6,876,946

The present invention has been made under the circumstances described above. From a first viewpoint, the present invention is an exposure method for sequentially transferring a pattern formed on a mask onto a plurality of objects, and among the plurality of objects, Detecting a plurality of first marks attached to at least a part of a plurality of partition areas arranged on one object, and using the detection result, the first pattern formed in the plurality of partition areas is detected. A first step of obtaining a position error; detecting a plurality of second marks attached to at least a part of the plurality of partitioned areas onto which the second pattern is transferred so as to overlap the first pattern, and using the detection result overlapping of the case where the overlay error is out of the allowable range, in the position error and the second pattern in the first pattern; second step and determining the overlay error of the second pattern with respect to the first pattern Te Misalignment By adding the correction amount during the exposure process to the sum of the, seek mask Shin shrinkage variation amount during the exposure process when the second pattern is formed which compensation using the mask stretching variation mask stretch correction model to verify the accuracy of the verification third that correct the mask Shin contraction correction parameter Osamu accordance with the results step and for, said using mask Shin contraction correction parameters correct Osamu second A fourth pattern in which a pattern overlay error is corrected, and the second pattern is transferred onto the first pattern formed in the plurality of partitioned regions arranged on the next object among the plurality of objects. And a first exposure method comprising:

According to this, the position error of the first pattern obtained from the detection results of the plurality of first marks and the plurality of second marks for one object among the plurality of objects, and the second pattern with respect to the first pattern A correction amount during the exposure process is added to the sum of the overlay error and a mask (reticle) expansion / contraction variation amount during the exposure process when the second pattern is formed, and the mask expansion / contraction variation amount is used. The parameters of the correction model for correcting this are corrected. The second pattern can be transferred onto the next object after correcting the alignment error using the corrected correction parameter. Therefore, even if the degree of deformation of the mask is enlarged when the second pattern is transferred to the previous object, sufficient overlay accuracy (positioning accuracy) is obtained when the second pattern is transferred to the next object. Is possible.

According to a second aspect of the present invention, there is provided an exposure method for sequentially transferring a pattern formed on a mask onto a plurality of objects, wherein the plurality of patterns on the object on which the second pattern is transferred over the first pattern. A first step of detecting a plurality of marks attached to at least a part of the partition area and determining an overlay error of the second pattern with respect to the first pattern using the detection result;
When the overlay error is outside an allowable range , information on an alignment condition and an alignment result corresponding to the alignment condition is acquired, and the second derived from deformation of the mask on which the second pattern is formed. Position for correcting a residual when a parameter included in a correction model for correcting a pattern overlay error is optimized and the correction model after the optimization is applied to correct the overlay error of the second pattern A second step of calculating an alignment condition; applying the optimized correction model ; and a plurality of partitioned regions arranged on a next object among the plurality of objects according to the calculated alignment condition And a third step of transferring the second pattern so as to overlap the first pattern already formed therein.

  According to this, when the overlay error is outside the allowable range, the parameter included in the mask deformation correction model for correcting the overlay error of the second pattern derived from the mask deformation is optimized, and the optimum The alignment conditions for correcting the residual when the overlay error of the second pattern is corrected by applying the corrected correction model are applied, and the mask deformation correction model with optimized parameters is applied and calculated. In accordance with the alignment conditions, the second pattern is transferred so as to overlap the first pattern already formed in the plurality of partitioned regions arranged on the next object among the plurality of objects.

  Therefore, even when the degree of deformation of the mask is enlarged when the second pattern is transferred to the previous object, sufficient overlay accuracy (positioning accuracy) is obtained when the second pattern is transferred to the next object. It becomes possible.

  According to a third aspect of the present invention, there is provided a step of forming a pattern on a plurality of objects using any one of the first and second exposure methods of the present invention; and the object on which the pattern is formed. And a developing process.

According to a fourth aspect of the present invention, there is provided at least one exposure apparatus that sequentially transfers a pattern formed on a mask onto a plurality of objects; and a first mark detection system that detects marks existing on the objects. And detecting a plurality of first marks attached to at least a part of a plurality of partitioned areas arranged on one of the plurality of objects using the first mark detection system, and detecting the result A first measuring device for obtaining a position error of the first pattern formed in the plurality of partitioned areas based on the first pattern; a second mark detection system for detecting a mark present on the object; and the first pattern Detecting a plurality of second marks attached to at least a part of the plurality of partitioned areas on the object, the second pattern being transferred by the exposure apparatus, and using the second mark detection system, In the detection result A second measuring device for determining an overlay error of the second pattern with respect to the first pattern; and a host computer for overall management of the exposure device and the first and second measuring devices. and any of the host computer, when said overlay error obtained by the second measurement device is outside the acceptable range, before Symbol overlay error at the position error and the second pattern in the first pattern by adding the correction amount during the exposure process to the sum of the obtains the mask stretching variation amount in the second pattern during the exposure process when that will be formed, in order to correct this by using the mask stretching variation to verify the accuracy of the mask stretching correction model, modifying the mask stretch correction parameter according to the verification result and (optimized), the exposure apparatus, the mask stretch correction parameter The second pattern is superimposed on the first pattern already formed in a plurality of partitioned areas arranged on the next object among the plurality of objects, by correcting an overlay error of the second pattern according to a result of use. Is an exposure system for transferring the image.

  According to this, the position error of the first pattern obtained from the detection results of the plurality of first marks and the plurality of second marks for one object among the plurality of objects, and the second pattern relative to the first pattern, respectively. The correction model parameters are corrected using the overlay error. The second pattern can be transferred onto the next object after correcting the overlay error using the corrected correction model. Therefore, even if the degree of deformation of the mask is enlarged when the second pattern is transferred to the previous object, sufficient overlay accuracy (positioning accuracy) is obtained when the second pattern is transferred to the next object. Is possible.

1 is a diagram showing a schematic configuration of a lithography system according to an embodiment. FIG. 2 is a view showing a schematic configuration of one exposure apparatus constituting the lithography system of FIG. 1. FIG. 3A is a diagram for explaining an example of the arrangement of sample shots of multi-point EGA in shot in advance measurement, and FIG. 3B is a sample of multi-point EGA in shot in alignment measurement during lot processing. It is a figure for demonstrating an example of arrangement | positioning of a shot. FIG. 4A is a diagram showing an example of the arrangement of alignment marks provided in sample shots on a wafer measured in the pre-measurement and post-measurement, and FIG. 4B is a diagram showing many shots in the shot during lot processing. It is a figure which shows an example of arrangement | positioning of the alignment mark provided in the sample shot measured by point measurement. It is a flowchart corresponding to the processing algorithm of the lot processing sequence performed by the host. It is a flowchart which shows an example of the subroutine of step 522 of FIG. FIGS. 7A and 7B show shot scaling before and after optimizing the reticle expansion / contraction correction parameter, which is obtained by calculating the reticle expansion / contraction variation amount and reticle expansion / contraction correction amount for each wafer in the lot. It is a figure which shows X and shot scaling Y.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 7B.

FIG. 1 schematically shows the configuration of a lithography system 100 according to an embodiment suitable for carrying out the exposure method according to the present invention. The lithography system 100 includes N exposure apparatuses 110 _{1 to} 110 _N , an overlay measurement apparatus (hereinafter simply referred to as “measurement apparatus”) 130, a storage device 140, a terminal server 150, and a host computer (hereinafter “host”). 160) and the like.

Exposure apparatuses 110 _{1 to} 110 _N , measurement apparatus 130, and terminal server 150 are connected to a local area network (LAN) 170. A host 160 is connected to the terminal server 150. A storage device 140 is connected to the host 160 via a communication path 180 such as a scuzzy (SCSI). That is, on the hardware configuration, communication paths among the exposure apparatuses 110 _{1 to} 110 _N , the measurement apparatus 130, the terminal server 150, and the host 160 (and the storage device 140) are secured.

The exposure apparatuses 110 _{1 to} 110 _N are at least one scanning exposure apparatus, for example, a step-and-scan type projection exposure apparatus (that is, a scanner), and has an ability to adjust distortion of a projected image. A projection exposure apparatus (hereinafter simply referred to as an exposure apparatus unless otherwise required) 110 _n (n is any one of 1 to N) is included.

FIG. 2 shows a schematic configuration of the exposure apparatus 110 _n . The exposure apparatus 110 _n includes an illumination system IOP, a reticle stage RST that holds the reticle R, a projection optical system PL, a wafer stage WST on which the wafer W is placed, a control system for these, and the like.

  The illumination system IOP includes a light source and an illumination optical system connected to the light source via a light transmission optical system. The illumination optical system includes, for example, an illumination uniformizing optical system including an optical integrator, a beam splitter, a reticle blind, and the like (all not shown) as disclosed in, for example, US Patent Application Publication No. 2003/0025890. . Illumination system IOP uses illumination light IL to illuminate a slit-like illumination area defined by a reticle blind on reticle R on which a circuit pattern or the like is drawn (a long and narrow rectangular shape extending in the X-axis direction (the direction perpendicular to the plane of FIG. 2)). Illuminate with almost uniform illumination. As the illumination light IL, for example, ArF excimer laser light (wavelength 193 nm) (or KrF excimer laser light (wavelength 248 nm)) is used.

  Reticle stage RST is arranged below illumination system IOP in FIG. 2 (on the −Z side). On reticle stage RST, reticle R on which a pattern is formed is fixed, for example, by vacuum suction. Here, reticle stage RST can be finely driven in a horizontal plane (XY plane) by a reticle stage drive system 22 including a linear motor and the like, and also has a scanning direction (here, the Y axis in the horizontal direction in FIG. 2). Driving at a scanning speed specified in a predetermined stroke range. Position information (including rotation information about the Z axis) of the reticle stage RST in the XY plane is, for example, about 0.25 nm by a reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 16 via a movable mirror 15. Is always detected with a resolution of. Position information of reticle stage RST from reticle interferometer 16 is sent to main controller 50, which drives reticle stage RST via reticle stage drive system 22 based on the position information of reticle stage RST. (Control.

  Projection optical system PL is arranged below reticle stage RST in FIG. 2 (on the −Z side), and the direction of optical axis AX is the Z-axis direction. The projection optical system PL includes, for example, a plurality of lens elements 27, 29, 30, 31,... Arranged at a predetermined interval along the Z-axis direction parallel to the optical axis AX. A telecentric refraction system is used. The lens elements 27, 29, 30, 31... Are held inside the lens barrel 32. The projection magnification of the projection optical system PL is, for example, 1/5 (or 1/4). For this reason, when the reticle R is illuminated by the illumination light IL from the illumination system IOP, the illumination light IL that has passed through the reticle R passes through the projection optical system PL and is within the illumination area (illumination area) of the illumination light IL. A reduced image (partially inverted image) of the reticle R pattern is formed in an area (exposure area) conjugate to the illumination area on the wafer W coated with a resist (sensitizer) on the surface (pattern latent in the resist). An image is formed).

The exposure apparatus 110 _n is provided with an imaging characteristic correction apparatus for correcting imaging characteristics of the projection optical system PL, for example, various aberrations. This imaging characteristic correction device corrects changes in imaging characteristics of the projection optical system PL itself due to changes in atmospheric pressure, absorption of illumination light, and the like, and shot regions (for example, the previous layer) of a preceding specific layer on the wafer W Hereinafter, the projection image of the pattern on the reticle R is distorted in accordance with the distortion of the pattern transferred to the shot). Imaging characteristics of the projection optical system PL include spherical aberration (aberration at the imaging position), coma aberration (magnification aberration), astigmatism, field curvature, distortion aberration (distortion), and the like. The imaging characteristic correction apparatus has a function of correcting these aberrations. In the following description, the imaging characteristic correction apparatus mainly expands and contracts a mask (reticle) by absorbing exposure power during lot processing. It is assumed that distortion (including magnification aberration) of the projected image (transfer image) due to fluctuation is corrected over time.

  In FIG. 2, the lens element 27 that is the closest to the reticle R constituting the projection optical system PL is fixed to the support member 28, and the lens elements 29, 30, 31,... Following the lens element 27 are lens mirrors of the projection optical system PL. It is fixed to the cylinder 32. The support member 28 is projected optically via a plurality of (three in this case) drive elements that can be expanded and contracted, for example, piezo elements 11a, 11b, and 11c (however, the drive element 11c on the back side of the paper is not shown in FIG. 2). It is connected to the lens barrel 32 of the system PL. The drive voltage applied to the drive elements 11a, 11b, and 11c is independently controlled by the imaging characteristic control unit 12, whereby the lens element 27 is arbitrarily inclined and optical axis with respect to the plane orthogonal to the optical axis AX. It is configured to be movable in a direction parallel to AX. The driving amount of the lens element 27 by each driving element is strictly measured by a position sensor (not shown), and the position is maintained at a target position by servo control. Note that the optical axis AX of the projection optical system PL indicates the common optical axis of a fixed lens element such as the lens element 29.

  In the above description, for the sake of convenience of explanation, it is assumed that only the lens element 27 is movable. However, actually, in the projection optical system PL, a plurality of lens elements or lens groups include the above lens. Like the element 27, it is configured to be movable. Further, in the imaging characteristic correction apparatus, in addition to the configuration for correcting distortion of the projection image by moving a part of the optical elements that constitute the projection optical system PL, A configuration in which the distortion of the projected image is corrected by controlling the gas pressure (adjusting the refractive index) may be employed.

  Wafer stage WST is arranged below projection optical system PL in FIG. 2 (on the −Z side). Wafer holder 9 is mounted on wafer stage WST. A wafer W is held on the wafer holder 9 by vacuum suction or the like.

  Wafer stage WST is driven with a predetermined stroke in the X-axis direction and Y-axis direction by wafer stage drive system 24 including a linear motor and the like, and also rotates in the Z-axis direction and the Z-axis rotation direction (θz direction). It is finely driven in a rotating direction (θx direction) around and a rotating direction around the Y axis (θy direction). That is, the wafer holder 9 can be tilted in any direction with respect to the best imaging plane of the projection optical system PL by the wafer stage drive system 24, and can be finely moved in the optical axis AX direction (Z-axis direction). It is configured to be rotatable around a Z axis parallel to the axis AX. In place of wafer stage WST, a stage that can move (including rotation in the θz direction) in the XY plane, and a wafer holder 9 held on the stage, can be finely moved in the Z-axis direction, θx direction, and θy direction. A table may be used.

  Position information (including yawing (rotation in the θz direction) information) and tilt information (pitching (rotation in the θx direction) information and rolling (rotation in the θy direction) information) of the wafer stage WST in the XY plane are the wafer laser. An interferometer (hereinafter abbreviated as a wafer interferometer) 18 is constantly detected through a movable mirror 17 with a resolution of, for example, about 0.25 nm. The position information (or speed information) of wafer stage WST is sent to main controller 50, and main controller 50 determines the position of wafer stage WST in the XY plane (in the θz direction) based on the position information (or speed information). (Including rotation) is controlled via the wafer stage drive system 24.

  Further, a reference mark plate FM having a surface set substantially at the same height as the surface of wafer W is fixed to the upper surface of wafer stage WST. On the surface of the fiducial mark plate FM, a first fiducial mark for reticle alignment and a second fiducial mark for baseline measurement of the alignment system 8 described later are formed in a predetermined positional relationship.

  On the side surface of the projection optical system PL, there is an off-axis alignment system 8 for detecting an alignment mark (wafer mark) attached to each shot on the wafer W and a second reference mark on the reference mark plate FM. Is provided. As the alignment system 8, for example, an FIA (Field Image Alignment) system of an image processing system is used. In addition to the FIA system, a target mark is irradiated with coherent detection light, and scattered light or diffracted light generated from the target mark is detected, or two diffracted lights (for example, of the same order) generated from the target mark. Of course, it is possible to use an alignment sensor that detects the interference by interfering with each other alone or in combination. The detection result of the alignment system 8 is sent to the main controller 50 via an alignment signal processing system (not shown).

  Further, in the vicinity of the lower end portion of the projection optical system PL, a multipoint focal position for detecting position information (surface position information) regarding the Z-axis direction of the surface of the wafer W at the plurality of detection points in the exposure area and in the vicinity thereof. A detection system (13, 14) is provided. As the multipoint focal position detection system, for example, an oblique incidence type detection system disclosed in US Pat. No. 5,448,332 is used. The multipoint focal position detection system includes an irradiation optical system 13 that emits an imaged light beam obliquely with respect to the optical axis AX toward the best image formation plane of the projection optical system PL, and a reflected light beam from the surface of the wafer W as a slit. And a light receiving optical system 14 for receiving light through The wafer surface position information detected by the multipoint focal position detection system (13, 14) is supplied to the main controller 50. Based on the supplied wafer surface position information, main controller 50 drives wafer stage WST (wafer holder 9) in the Z-axis direction and the tilt direction via wafer stage drive system 24 to focus / Perform leveling control.

In addition, the exposure apparatus 110 _n is provided with a pair of reticle alignment systems (not shown) as disclosed in, for example, US Pat. No. 5,646,413 above the reticle stage RST. . The reticle alignment system is composed of a TTR (Through The Reticle) alignment system using light having the same wavelength as the illumination light IL. The detection signal of the reticle alignment system is supplied to main controller 50 via an alignment signal processing system (not shown).

The main controller 50 is composed of, for example, a microcomputer (or workstation), and comprehensively controls each component of the exposure apparatus 110 _n . The main controller 50 also controls a coater / developer (not shown) (hereinafter referred to as “C / D”) provided in the exposure apparatus 110 _n . As shown in FIG. 2, the main controller 50 is connected to the LAN 170 and can communicate with main controllers of other exposure apparatuses 110 _{1 to} 110 _N (except 110 _n ) (FIG. 1). reference).

Next, the operation of the exposure process in the exposure apparatus 110 _n will be briefly described.

  Prior to exposure, main controller 50 causes wafer W to be loaded onto wafer holder 9 using a wafer transfer system (not shown), reticle alignment and baseline measurement of alignment system 8, and wafer alignment (for example, multiple points in a shot) EGA) and other preparatory work is performed. The above reticle alignment, baseline measurement, and the like are disclosed in detail in the aforementioned US Pat. No. 5,646,413. Subsequent multi-point EGA within a shot is disclosed in detail in US Pat. No. 6,876,946. Here, the in-shot multipoint EGA is a statistic using the least square method disclosed in, for example, the above-mentioned US Pat. No. 6,876,946 using position detection data of a plurality of wafer alignment marks in a shot. This means an alignment method (details will be described later) for obtaining a deformation amount including the arrangement coordinates of all shots on the wafer W and the magnification (scaling), rotation, and orthogonality of each shot using a geometric method.

  Main controller 50 sequentially transfers the pattern of reticle R to all shots on wafer W by scanning exposure based on the results of reticle alignment and baseline measurement described above and the results of wafer alignment.

  In scanning exposure for each shot on wafer W, main controller 50 scans reticle stage RST and wafer stage WST while monitoring measurement information (positional information) by reticle interferometer 16 and wafer interferometer 18. Move to the start position (acceleration start position). Then, main controller 50 relatively drives both stages RST and WST in the Y-axis direction, but in opposite directions. Here, when both stages RST and WST reach their respective target speeds, the pattern area of reticle R starts to be illuminated by illumination light IL, and scanning exposure is started.

  Main controller 50 determines that the speed Vr of reticle stage RST in the Y-axis direction and the movement speed Vw of wafer stage WST in the Y-axis direction at a speed ratio corresponding to the projection magnification of projection optical system PL, particularly during the above-described scanning exposure. The reticle stage RST and wafer stage WST are synchronously controlled so as to be maintained. At this time, main controller 50 adjusts the synchronous drive of both stages RST and WST or drives lens element 27 via the imaging characteristic correction device to project the pattern of reticle R onto the wafer W. Correct distortion. Here, the adjustment of the synchronous drive of both stages RST and WST means that reticle R (reticle stage RST) and wafer W (wafer stage WST) at the time of scanning exposure via reticle stage drive system 22 and wafer stage drive system 24. And adjusting the speed ratio in the scanning direction, and slightly shifting the scanning direction of both stages RST and WST. According to the former, the magnification of the projected image in the scanning direction can be corrected, and according to the latter, the projected image can be distorted.

  Then, different areas of the pattern area of the reticle R are sequentially illuminated with the illumination light IL, and the illumination of the entire pattern area is completed, thereby completing the scanning exposure of the first shot on the wafer W. Thereby, the circuit pattern of the reticle R is reduced and transferred to the first shot via the projection optical system PL.

  When the scanning exposure for the first shot is completed, main controller 50 moves (steps) wafer stage WST to the scanning start position (acceleration start position) for the next second shot. Then, similarly to the above, the scanning exposure for the second shot is performed. Thereafter, the same operation is performed for the third and subsequent shots. In this manner, the stepping operation between shots and the scanning exposure operation for the shots are repeated, and the pattern of the reticle R is transferred to all shots on the wafer W by the step-and-can method.

Among other exposure apparatuses, a projection exposure apparatus which is a scanning exposure apparatus is configured in the same manner as the projection exposure apparatus 110 _n . A projection exposure apparatus composed of a static exposure apparatus is basically configured in the same manner as the projection exposure apparatus 110 _n shown in FIG. However, in these static exposure apparatuses, the respective reticle stages are configured so that they can only be finely driven in the X, Y, and θz directions in the XY plane, and the illumination light within the circular field of the projection optical system PL. The irradiation area of IL (corresponding to the above-described illumination area and exposure area) is larger than that of the scanning exposure apparatus of FIG. 2, and is different in that, for example, it has the same size as the scanning exposure range of the scanning exposure apparatus. This is because these projection exposure apparatuses perform exposure with both the wafer stage and the reticle stage stationary.

Returning to FIG. 1, the measuring device 130 is in-line connected to the exposure devices 110 _{1 to} 110 _N (including the exposure device 110 _n ). The measurement device 130 measures the formation state and overlay state of the pattern formed on the wafer as described above. More specifically, the measurement device 130 detects the alignment mark formed on the wafer together with the pattern, as in the alignment measurement (EGA) described above. As a result, the absolute position (deviation from the design position) of the mark formed in the current process layer and the relative position (position deviation) between the marks formed in different layers are obtained as a formation error and an overlay error, respectively. It is done. The measurement result obtained by the measuring apparatus 130 is supplied to the host 160 or the main controller 50 of the exposure apparatus 110 _n . When the measurement apparatus 130 analyzes the overlay state of the patterns formed on the original process layer prior to exposure on the current process layer, the pattern formed on the wafer previously exposed prior to exposure of the target wafer. It is used when analyzing the thermal deformation of a reticle by measuring the formation state of the reticle.

The main control device and the measurement device 130 provided in each of the exposure devices 110 _{1 to} 110 _N are connected to the LAN 170 and communicate with the host 160 via the LAN 170 and the terminal server 150. Here, the terminal server 150 is configured as a gateway processor for absorbing differences in communication protocols between the LAN 170 and the host 160. The function of the terminal server 150 enables communication between the host 160 and the exposure apparatuses 110 _{1 to} 110 _N and the measurement apparatus 130 connected to the LAN 170.

The host 160 is a large computer that centrally manages the lithography system 100. The host 160 periodically exposes exposure histories (for example, lot names of wafers processed by the exposure apparatuses, process program names, and processing times) sent from the exposure apparatuses 110 _{1 to} 110 _N and exposures. Information relating to the distortion of the projected images of the devices 110 _{1 to} 110 _N is stored in the storage device 140. The host 160 schedules the operation of all exposure apparatuses in the exposure process (including all device processing processes) of all wafers (lots) based on the exposure history.

In addition, the host 160 uses the results of wafer alignment (EGA) performed prior to exposure in the exposure apparatuses 110 _{1 to} 110 _N , the results of formation errors and overlay errors measured by the measurement apparatus 130, and the like. At this time, correction information for eliminating the overlay error is created, and the created correction information is stored in the storage device 140. When the host 160 instructs the exposure apparatus 110 _n to expose the wafer, the host 160 reads out necessary correction information from the storage device 140 and transmits it to the exposure apparatus 110 _n . The creation of the correction information will be described later.

  The host 160 is provided with an input / output device 161 such as a display, which is a man-machine interface, a keyboard, and a mouse. The operator can also input the correction parameters described above via the input / output device 161.

  The LAN 170 can be either a bus type LAN or a ring type LAN. In this embodiment, the carrier type medium access / contention detection (CSMA / CD) type bus type LAN of the IEEE 802 standard is adopted. Yes.

In the lithography system 100 of the present embodiment, particularly when a semiconductor device is manufactured, patterns of as many as ten to twenty layers are formed on the wafer so as to overlap each other. Accuracy (positioning accuracy) is required. Therefore, in the exposure apparatus 110 _n , the control apparatus performs the above-described wafer alignment (for example, multi-shot EGA within a shot), and adjusts the synchronous drive of both stages RST and WST based on the result and necessary correction information. Then, the distortion of the projected image of the pattern is corrected using the imaging characteristic correction device, and the exposure process is executed.

  During the exposure process (lot processing), the reticle is thermally deformed by absorbing the illumination light, and the pattern image (projected image) projected on the wafer is distorted due to the thermal deformation of the reticle. Furthermore, since wafers are continuously exposed in units of lots (usually 25 or 50 for one lot) using the same reticle, reticle deformation (particularly expansion and contraction) increases each time the wafer is exposed. As a result, the distortion of the projected image of the pattern also increases.

  FIGS. 7A and 7B show, for each wafer in a lot, shot scaling that occurs due to the difference between the reticle expansion / contraction variation during lot processing and the expansion / contraction correction during exposure (before optimization). X (X scaling) and shot scaling Y (Y scaling) are shown using black circles. According to FIGS. 7A and 7B, it can be seen that each time the wafer is exposed, the shot scaling increases, that is, the reticle extends. For this reason, even if precise wafer alignment (for example, in-shot multi-point EGA wafer alignment) that considers even shot deformation prior to the start of wafer exposure, sufficient overlay accuracy (positioning accuracy) can be obtained. Absent.

  In view of this point, in the lithography system 100 of this embodiment, every time a wafer is exposed, a pattern overlay error (positioning error) resulting from reticle deformation (particularly expansion and contraction) is sequentially corrected to sequentially correct one lot. A lot processing sequence for continuously exposing the wafer is adopted.

  FIG. 5 shows a flowchart corresponding to the processing algorithm of the lot processing sequence performed by the host 160.

The flowchart (lot processing sequence) in FIG. 5 is started by an instruction from the host 160 (or an operator via the host 160). In giving the instruction, the host 160 designates the content of the exposure process, that is, the lot to be exposed, the exposure apparatus to be used (here, the exposure apparatus 110 _n ), the reticle to be used (here, the reticle R), and the like. At the same time, the designated lot is carried into the exposure apparatus 110 _n . One lot includes K wafers W _k (k = 1 to K, K = 25 as an example). In exposure apparatus 110 _n , designated reticle R is loaded onto reticle stage RST.

[Step 502]
In the first step 502, a counter k indicating the number of the wafer in the lot is initialized to 1 (k ← 1).

[Step 504]
In the next step 504, the wafer W _{k to be} exposed (here, the first wafer W ₁ ) is transferred to the overlay measurement device (measurement device) 130. Wafer W _k is a resist on the surface thereof by the in-line connected coater developer (C / D (not shown)) is conveyed to the measuring apparatus 130 in a state of being applied to the exposure apparatus 110 _n.

[Step 506]
In the next step 506, the measurement apparatus 130 is used to perform preliminary measurement on the wafer _Wk to be exposed.

  In the preliminary measurement, the host 160 optimizes the alignment processing conditions. Here, the alignment processing conditions include alignment mark (wafer mark) design conditions, alignment mark detection conditions, processing conditions for processing alignment mark detection results, alignment error correction methods, and the like. The alignment mark design conditions include the number, arrangement, and shape of alignment marks. The detection conditions include the wavelength and intensity of the detection light when detecting the alignment mark by irradiating the detection light, the width and shape of the illumination area, the phase difference, and the like. The processing conditions include an EGA calculation model, which will be described later, and the correction method includes a correction model for correcting distortion of the projected image of the pattern accompanying the expansion and contraction of the reticle.

In response to an instruction from the host 160, the measuring apparatus 130 performs wafer alignment (multi-point EGA within a shot) on the wafer Wk for each of the above alignment processing conditions. The wafer alignment result is transmitted from the measuring apparatus 130 to the host 160. The host 160 determines optimal alignment processing conditions using the received result. Note that an alignment process condition that gives the minimum alignment residual error described later is an optimum condition. The determined optimum alignment processing conditions are transmitted from the host 160 to the measuring apparatus 130 and the exposure apparatus 110 _n .

FIG. 3 (A), a plurality of shots arranged on the wafer W _k are shown. By optimizing the alignment processing conditions above, as an example, shots Sa1, Sa2, Sa3, Sa4, Sa5, Sa6, Sb1, Sb2, Sb3, Sb4, Sb5, Sb6, Sc1, Sc2, Sc3, Sc4, Sc5, Sc6, Sd1, Sd2, Sd3, Sd4, Sd5, and Sd6 are determined as shots (sample shots) in which alignment marks for multi-shot EGA within a shot are detected.

FIG. 4A shows an example of the arrangement of alignment marks M _ij (i, j = 1 to 8) provided in the sample shot. A total of 64 alignment marks M _ij (i, j = 1 to 8) are attached in the sample shot, 8 in the X-axis direction and 8 in the Y-axis direction. The interval between the X-axis direction and the Y-axis direction is ΔD. As an example, the positions of these alignment marks M _ij (i, j = 1 to 8) are measured in advance measurement and post-measurement (multi-point EGA in a shot) by optimization of the above alignment processing conditions. It is determined as a target mark (to be detected).

In the pre-measurement, an alignment mark for wafer alignment (multi-shot EGA in a shot) is detected for the wafer W _k under the optimum alignment processing conditions determined above. The measurement apparatus 130 is configured to use the sample shots Sa1, Sa2, Sa3, Sa4, Sa5, Sab1, Sb2, Sb3, Sb4, Sb5, Sb6, Sc1, Sc2, Sc3, Sc4, Sc5 shown in FIG. Alignment marks M _ij (i, j = 1 to 8) arranged as shown in FIG. 4A attached to each of Sc6, Sd1, Sd2, Sd3, Sd4, Sd5, and Sd6 are detected, and a wafer coordinate system ( Alternatively, the positions (X position, Y position) ξ _ij and ζ _ij of the alignment mark M _ij (i, j = 1 to 8) on the stage coordinate system) are measured. The measurement result is transferred from the measurement device 130 to the host 160.

The host 160 obtains shot scaling for the wafer W _k using the measurement results ξ _ij and ζ _ij of the alignment mark M _ij (i, j = 1 to 8). Here, the alignment mark M _ij (i, j = 1 to 8) is formed together with the pattern formed in the original process layer. Therefore, the required shot scaling corresponds to the formation error of the pattern formed in the original process layer. In practice, the alignment mark M _ij (i, j = 1 to 8) is formed on the street that partitions the shot in which the pattern is formed simultaneously with the pattern formed in the original process layer. Here, for convenience of explanation, it is assumed that they are arranged in the shot.

As an example of a calculation model (EGA calculation model) for numerically processing the measurement results ξ _ij and ζ _ij by optimizing the previous alignment processing conditions, the following third-order shot array deformation calculation model (including shot linear components) Assume that (1a) and (1b) are determined.

ΔX = Cx ₃₀ Wx ³ + Cx ₂₁ Wx ² Wy + Cx ₁₂ WxWy ² + Cx ₀₃ Wy ³
+ Cx ₂₀ Wx ² + Cx ₁₁ WxWy + Cx ₀₂ Wy ²
+ Cx ₁₀ Wx + Cx ₀₁ Wy + Cx ₀₀ + Cx _SX Sx + Cx _SY Sy (1a)
ΔY = Cy ₃₀ Wx ³ + Cy ₂₁ Wx ² Wy + Cy ₁₂ WxWy ² + Cy ₀₃ Wy ³
+ Cy ₂₀ Wx ² + Cy ₁₁ WxWy + Cy ₀₂ Wy ²
+ Cy ₁₀ Wx + Cy ₀₁ Wy + Cy ₀₀ + Cy _SX Sx + Cy _SY Sy (1b)

In the above EGA calculation models (1a) and (1b), (Wx, Wy) and (Sx, Sy) are design positions of the alignment mark with respect to the wafer center and the shot center, respectively. Also, (Cx ₁₀ , Cy ₀₁ ) is wafer scaling, (Cx ₀₁ , Cy ₁₀ ) is wafer rotation, (Cx ₀₀ , Cy ₀₀ ) is wafer offset, (Cx _SX , Cy _SY ) is shot scaling, (Cx _SY , Cy _SX ) is a shot rotation. These coefficients are collectively referred to as EGA parameters. In correspondence with EGA parameters disclosed in US Pat. No. 6,876,946, etc., wafer orthogonality Ω = − (Cx ₀₁ + Cy ₁₀ ), wafer rotation Θ = Cy ₁₀ , shot orthogonality ω = − (Cx _SY + Cy _SX ), shot rotation θ = Cy _SX

The host 160 uses the measurement results ξ _ij and ζ _ij to minimize the alignment residual error ε = Σ _{ij = 1 to 8} ((ξ _ij −ΔX _ij ) ² + (ζ _ij −ΔY _ij ) ² ). Next, the least square method is applied to determine EGA parameters and coefficients included in the model. Here, ΔX _ij and ΔY _ij (i, j = 1 to 8) are corrections of alignment marks M _ij (i, j = 1 to 8) calculated by applying the calculation models (1a) and (1b). Amount. That is, ΔX and ΔY on the left side obtained by substituting the design position into (Wx, Wy) and (Sx, Sy) on the right side of the calculation models (1a) and (1b).

The host 160 records the shot scaling Cx _SX and Cy _SY for the wafer W _k obtained as described above in the storage device 140. Thereby, preliminary measurement is completed.

[Step 508]
In the next step 508, the wafer W _k that has been pre-measured, is conveyed to the exposure apparatus 110 _n via the transport system (not shown). Wafer _{W k} that has been conveyed to the exposure apparatus 110 _n is loaded onto the wafer stage WST.

[Step 510]
In the next step 510, instruction is given to the exposure apparatus 110 _n, performs wafer alignment (shot Uchida point EGA) on the wafer _{W k} to be exposed. Similar to the previous measurement, the sample shot shown in FIG. 3A as a sample shot of EGA measurement is, for example, a third-order shot arrangement deformation calculation model (including a shot linear component) (1a), Assume that (1b) is selected.

  In addition, in the multipoint measurement in the shot immediately before exposure in this step 510, from the viewpoint of maintaining or improving the throughput, the number is less than 24 shown in FIG. For example, a part of 24 shots is measured. For example, as shown in FIG. 3B, eight shots of sample shots Sa1, Sa2, Sb1, Sb2, Sc1, Sc2, Sd1, and Sd2 are measured.

For the measurement target shot, a smaller number of alignment marks than 64 shown in FIG. 4A, for example, a part of the 64 alignment marks are detected. For example, as shown in FIG. 4B, a total of 16 alignment marks m _ij (i, j = 1 to 4) are detected, four in the X-axis direction and four in the Y-axis direction. Here, the interval Δd in the X-axis direction and the Y-axis direction of the alignment mark m _ij (i, j = 1 to 4) is the alignment mark M _ij (i, j = 1 to 8) used in the previous preliminary measurement. Is larger than the interval ΔD (Δd> ΔD).

The main controller 50 of the exposure apparatus 110 _n performs, as shown in FIG. 3B, the wafer W _k under the optimal alignment processing conditions determined in advance as multipoint measurement in the shot immediately before exposure in step 510. 16 alignment marks m _ij (i, j = 1 to 4) shown in FIG. 4B, which are given in the sample shots Sa1, Sa2, Sb1, Sb2, Sc1, Sc2, Sd1, Sd2 shown in FIG. ) And the positions (X position, Y position) ξ _ij and ζ _ij of the alignment mark m _ij (i, j = 1 to 4) on the wafer coordinate system (or stage coordinate system).

The main controller 50 applies the shot arrangement deformation calculation model (including the shot linear component) (1a) and (1b), and calculates the wafer component (shot) from the measurement results ξ _ij and ζ _ij (i, j = 1 to 4). Array error) and shot linear components are removed. The main controller 50 uses the measurement results ξ _ij and ζ _ij to minimize the alignment residual error ε = Σ _{ij = 1 to 4} ((ξ _ij −ΔX _ij ) ² + (ζ _ij −ΔY _ij ) ² ). As such, the least squares method is applied to determine EGA parameters and coefficients included in the model. ΔX _ij , ΔY _ij (i, j = 1 to 4) are correction amounts of the alignment mark m _ij (i, j = 1 to 4) converted by applying the calculation models (1a) and (1b). It is. That is, ΔX and ΔY on the left side obtained by substituting the design position into (Wx, Wy) and (Sx, Sy) on the right side of the calculation models (1a) and (1b).

The main controller 50 uses the determined EGA parameters and coefficients to remove the wafer components (shot alignment error) and the shot linear components from the measurement results ξ _ij and ζ _ij (i, j = 1 to 4), thereby remaining. An error (that is, an error in a shot) dξ _ij = ξ _ij −ΔX ′ _ij , dζ _ij = ζ _ij −ΔY ′ _ij (i, j = 1 to 4) is obtained. Here, ΔX ′ _ij and ΔY ′ _ij are correction amounts of the alignment mark m _ij (i, j = 1 to 4) calculated by applying the EGA calculation models (1a) and (1b).

  If a higher-order component is included in the wafer component (shot arrangement error), it is similarly removed. Details of handling higher order components are disclosed, for example, in US 2006/0040191.

[Step 512]
In the next step 512, the exposure apparatus 110 _n exposes the wafer W _k by the above-described scanning exposure in accordance with an instruction from the host 160. Here, main controller 50 of exposure apparatus 110 _n uses EGA parameters and coefficients obtained in wafer alignment (multi-point EGA within a shot) executed based on the optimum alignment processing conditions determined in advance measurement. The position coordinates on the stage coordinate system of the shot to be processed on the wafer are calculated. Main controller 50 drives lens element 27 via the imaging characteristic correction device and synchronizes reticle stage RST and wafer stage WST based on this calculation result and the results of reticle alignment and baseline measurement. The above-described scanning exposure is executed while finely correcting the driving. Then, the pattern of the reticle R is sequentially transferred to all shots on the wafer W. The details of driving the lens element for correcting the distortion of the projected image are described in, for example, US Pat. No. 5,117,255, and the details of the stage driving for correcting the distortion of the projected image are, for example, For example, it is disclosed in US Pat. No. 6,235,438. When the exposure for all shots on the wafer is completed, the process proceeds to step 514.
[Step 514]
In step 514, it is determined whether or not k <K is satisfied, thereby determining whether or not the exposure of all wafers W _k (k = 1 to K) in the lot has been completed. In this case, since k = 1, the determination here is affirmed, and the routine proceeds to the next Step 516.

[Step 516]
In step 516, the exposed wafer W _k is transferred from the exposure apparatus 110 _n to the overlay measurement apparatus (measurement apparatus) 130. However, the wafer W _k is transferred to the measuring device 130 in a state where a resist pattern is formed by being developed by a coater / developer (C / D (not shown)) connected inline to the exposure device 110 _n. .

[Step 518]
In the next step 518, post measurement is performed on the exposed wafer W _k using the measurement device 130. In the post-measurement, a shift (overlay) between the alignment mark newly formed by the exposure in step 512 and the mark of the original process layer is measured under the optimum alignment processing conditions determined in the pre-measurement. Here, the measuring device 130 is configured to use the sample shots Sa1, Sa2, Sa3, Sa4, Sa5, Sa6, Sb1, Sb2, Sb3, Sb4, Sb5, Sb6, Sc1, Sc2, Sc3, Sc4 shown in FIG. , Sc5, Sc6, Sd1, Sd2, Sd3, Sd4, Sd5, and Sd6, the alignment mark M _ij (i, j = 1 to 8) of the arrangement shown in FIG. X and Y relative positions (X and Y position shifts) Δξ _ij and Δζ _ij from the alignment marks already formed in the process layer are measured. The measurement result is transferred from the measurement device 130 to the host 160.

The host 160 uses the measurement results Δξ _ij and Δζ _ij of the alignment mark M _ij (i, j = 1 to 8), and similarly uses the shot arrangement deformation calculation model (including the shot linear component) (1a), ( shot scaling? Cx _SX to wafer _{W k} using 1b), obtains the cy _SY. However, the shot scaling Cx _SX and Cy _SY are determined so that the alignment residual error ε = Σ _{ij = 1 to 8} ((Δξ _ij −ΔX _ij ) ² + (Δζ _ij −ΔY _ij ) ² ) is minimized. Determined shot scaled _Cx SX, the _{Cy SY,} pre-measurement, or, wafer alignment measurement (shot Uchida point EGA) shot scaling _Cx SX determined in order to distinguish it from _{Cy SY,} respectively? Cx _SX, and cy _SY write. The required shot scaling ΔCx _SX , ΔCy _SY is the difference between the formation error of the pattern formed in the original process layer and the formation error of the pattern formed in the current process layer, that is, the overlay error of both patterns (formed in the original process layer) This corresponds to the overlay error of the pattern formed in the current process layer with respect to the formed pattern).

The host 160 records the shot scalings ΔCx _SX and ΔCy _SY obtained for the wafer W _k in the storage device 140. Thereby, the post measurement is completed.

[Step 520]
In the next step 520, the wafer W _k is unloaded from the measuring apparatus 130 via a transfer system (not shown), and then the process proceeds to step 521, where shot scaling ΔCx _SX , ΔCy _SY obtained in the post measurement (step 518). That is, it is determined whether or not the overlay error between the pattern formed in the original process layer and the pattern formed in the current process layer exceeds a predetermined threshold. When the judgment is affirmative, that is, the overlay error exceeds the threshold, the reticle R is stretchable (thermal expansion), whereby the image of the pattern of the reticle R to be transferred to the wafer W _k is deformed It can be determined that In this case, the process proceeds to a subroutine for reticle expansion correction & alignment processing condition optimization in step 522. On the other hand, if this determination is negative, that is, if the overlay error does not exceed the threshold value, step 522 is skipped and the process proceeds to step 524.
[Step 522]
In step (a subroutine) 522, first, in step 602 of FIG. 6, for each wafer _{W k,} the actual expansion variation E _X of the reticle _{R, k = E MX, k} + E LX, k + B X, k -S SX _{, k} , E _{Y, k} = E _{MY, k} + E _{LY, k} + B _{Y, k} −S _{SY, k} . Here, for each wafer W _k , shot scaling Cx _{SX, k} , Cy _{SY, k} obtained in the pre-measurement (step 506) and shot scaling ΔCx _{SX ,, k} , ΔCy _SY obtained in the post-measurement (step 518). _{, k} , the pattern formation error E _{MX, k} = Cx _{SX, k} + ΔCx _{SX, k} , E _{MY, k} = Cx _{SY, k} + ΔCx _{SY, k} is obtained in the current process layer.

Further, the shot scaling Cx _{SX, k} , Cy _{SY, k} obtained in alignment measurement (multi-point EGA in shot) (step 510) and the shot scaling ΔCx _{SX ,, k} , ΔCy obtained in post-measurement (step 518). _{Even if} the formation error E _{MX, k} = Cx _{SX, k} + ΔCx _{SX, k} , E _{MY, k} = Cx _{SY, k} + ΔCx _{SY, k} of the pattern formed in the current process layer is obtained from the sum of _{SY, k.} good.

In the above equation, E _{LX, k} , E _{LY, k} are lens control trace amounts (amount corrected by the imaging characteristic correction device), and B _{X, k} , _{BY, k} are magnification corrections by baseline measurement. The quantities S _{SX, k} and S _{SY, k} are preset fixed magnification offsets. These correction amounts are given from the exposure history for the wafer W _k transmitted from the main controller 50.

In the next step 603, using the following equation, in lot processing, obtaining the exposure power P _k that is absorbed by the reticle for each wafer W _k.

上式（２）において、Ｐ_kは１つ手前のウエハＷ_k-1からウエハＷ_ｋの露光処理かけてレチクルに吸収される露光パワー、Ｅ_L,k はウエハＷ_kにおけるレンズ制御トレース量、Ｅ_L,k-1,m は１つ手前のウエハＷ_k-1におけるレンズ制御トレース量（mは各成分）、ΔｔはウエハＷ_ｋ−１の露光とウエハＷ_ｋの露光との時間間隔、Ｔ_mとＳ_mはそれぞれレチクル伸縮の時定数と飽和値（mは各成分）である。

In the above equation (2), P _k is the exposure power absorbed by the reticle from the previous wafer W _k-1 to the wafer W _k , E _{L, k} is the lens control trace amount on the wafer W _k , E _{L, k-1, m} lens control trace amount (m each component) in the wafer W _k-1 in the immediately preceding is, Delta] t is the time interval between the exposure of the wafer W _k-1 of the exposure and the wafer W _k, T _m and S _m are the reticle expansion time constant and saturation value (m is each component), respectively.

In the next step 604, the reticle R expansion / contraction correction amount E _{X0, k,} E _{Y0, k} at the time of exposure of the wafer W _k is calculated from the next reticle expansion / contraction correction model.

ここで、Ｅ_X0,k-1,m は、１つ手前のウエハＷ_k-1におけるＸ方向のレチクル伸縮変動量、ΔｔはウエハＷ_ｋ−１の露光とウエハＷ_ｋの露光との時間間隔、Ｐ_ｋは１つ手前のウエハＷ_k-1からウエハＷ_ｋの露光処理かけてレチクルＲに吸収される露光パワー、Ｔ_XmとＳ_XmはそれぞれレチクルＲのＸ方向の伸縮の時定数と飽和値である。

Here, E _{X0, k-1, m} is one reticle telescopic variation in the X direction of the wafer W _k-1 in front, Delta] t is the time interval between the exposure of the wafer W _k-1 of the exposure and the wafer W _k , P _k is the exposure power absorbed by the reticle R from the previous wafer W _k-1 to the wafer W _k , T _Xm and S _Xm are the time constant and saturation of the reticle R in the X direction, respectively. Value.

ここで、Ｅ_Y0,k-1,m は、１つ手前のウエハＷ_k-1におけるＹ方向のレチクル伸縮変動量、ΔｔはウエハＷ_ｋ−１の露光とウエハＷ_ｋの露光との時間間隔、Ｐ_ｋは１つ手前のウエハＷ_k-1からウエハＷ_ｋの露光処理かけてレチクルＲに吸収される露光パワー、Ｔ_YmとＳ_YmはそれぞれレチクルＲのＹ方向の伸縮の時定数と飽和値である。なお、ここでは、レチクルＲの収縮と伸長の時定数は同じ値を用いている。

Here, E _{Y0, k-1, m} is one reticle telescopic variation in the Y direction of the wafer W _k-1 in front, Delta] t is the time interval between the exposure of the wafer W _k-1 of the exposure and the wafer W _k , P _k is the exposure power absorbed by the reticle R from the previous wafer W _k-1 to the wafer W _k , and T _Ym and S _Ym are the time constant and saturation of the reticle R in the Y direction, respectively. Value. Here, the same value is used for the time constant of contraction and expansion of reticle R.

  When calculating the reticle expansion / contraction correction amount at the time of exposure, the time constant and saturation value applied to the imaging characteristic correction device at the time of exposure are set.

  The first term in parentheses on the right side of the equations (3) and (4) represents the contraction of the reticle R due to heat release, and the second term represents the expansion of the reticle R due to heat absorption. Assuming that a plurality of mechanisms contribute to the expansion / contraction of the reticle R, the amount of correction for the expansion / contraction of the reticle R is obtained from the sum of the components of the plurality of m. In this embodiment, m = 3 is selected empirically.

Next, in step 608, the X-direction expansion / contraction correction amount E _{X0, k and} Y-direction expansion / contraction correction amount E _{Y0, k of} the reticle R obtained above are respectively measured in advance in advance (or alignment measurement). It is determined whether or not the reticle R is actually deviated from the actual X direction expansion / contraction variation amount E _{X, k and} Y direction expansion / contraction variation amount E _XYk obtained from the measurement result of the post measurement. If this determination is affirmative, that is, if the difference is larger than a predetermined threshold value, the process proceeds to step 610 to optimize the reticle expansion / contraction correction parameters (time constant and saturation value).

Specifically, when the X direction of the reticle telescopic, one before the wafer W actual expansion variation E _{X0, k-1,} and _m for _k-1, one in front of the wafer from the wafer W _k-1 W _k exposure power P _k absorbed in the reticle R by multiplying the exposure _process, and, the time interval Δt between the exposure of a front of the wafer W _k-1 of the exposure and the wafer W _k, respectively, the reticle stretch correction Substituting into the model (3), the reticle expansion / contraction correction amount at the time of wafer _Wk exposure is calculated. This is sequentially performed on the wafers W _{1 to} W _k , and the least square method is performed so that the residual sum of squares of the left side E _{X0, k} and the actual reticle expansion / contraction variation E _{X, k} is minimized. Apply to optimize T _Xm and S _Xm in the correction model (3).

If Y direction of the reticle telescopic, one and before the wafer W actual expansion variation E _Y0 for _{k-1, k-1, m,} the exposure process of the wafer W _k of the immediately preceding the wafer W _k-1 And the exposure power P _k absorbed by the reticle R and the time interval Δt between the exposure of the previous wafer W _{k-1 and} the exposure of the wafer W _k are respectively expressed in the reticle expansion / contraction correction model (4). By substituting, the reticle expansion / contraction correction amount at the time of wafer _Wk exposure is calculated. This is sequentially performed on the wafers W _{1 to} W _k , and the least square method is performed so that the residual sum of squares of the left side E _{Y0, k} and the actual reticle expansion / contraction variation E _{Y, k} is minimized. Apply to optimize T _Ym and S _Ym in the correction model (4).

7A and 7B, for each of the wafers W _k (k = 1 to 25), the actual expansion / contraction variation amount EX _{, k} when the reticle R is exposed and the time when the reticle R is exposed ( The difference between the expansion correction amount E _{X0, k} before the optimization) and the actual expansion variation amount E _{Y, k} when the reticle R is exposed and the expansion correction amount E _Y0, when the reticle R is exposed (before the optimization) _{The k} difference is shown using a black circle. Further, the difference between the actual expansion variation E _{X, k} and expansion correction amount E _{X0, k} optimized expected reticle R during exposure of the reticle R, and the actual expansion and contraction variation in exposure of the reticle R The difference between the predicted expansion / contraction correction amount E _{Y0, k} optimized for E _{Y, k} and reticle R is shown using white circles.

  It can be seen that by optimizing the reticle expansion / contraction correction parameters (saturation value and time constant) as described above, the reticle R expansion / contraction correction is optimized and the pattern overlay error is improved. Here, the reticle expansion / contraction fluctuation amount and correction amount are calculated for each wafer, but it is desirable in terms of overlay accuracy to calculate the reticle expansion / contraction variation amount and correction amount for each wafer shot.

  As described above, after optimizing the reticle expansion / contraction correction parameters (saturation value and time constant) in step 610, the process proceeds to step 612.

In step 612, the expected expansion / contraction correction amounts E _{X0, k} and E _{Y0, k} of the reticle R are obtained using the reticle expansion / contraction correction model equations (3) and (4), and the results are transmitted to the main controller 50. To do.

In the next step 614, the amount of change in the expansion / contraction correction before optimization and the expansion / contraction correction after optimization, that is, the predicted predicted X-direction expansion / contraction correction amount E _{X0, k} of the reticle R and the exposure of the reticle R are optimized. when the change amount of expansion and contraction correction amount E _{X0, k} in the X direction (before optimization) (difference), to be reflected in the superposition for each wafer W _k of X-direction measurement result. Similarly, the expansion and contraction correction amount E _{Y0, k} in the Y direction predicted optimized reticle R, the time of exposure of the reticle R variation of expansion and contraction correction amount E _{Y0, k} in the Y direction (before optimization) ( the difference) causes each wafer W _k are reflected in the Y direction overlay measurement result. As a result, if the pattern overlay error is smaller than the overlay threshold, the correction process is terminated, and if the pattern overlay error is larger than the overlay threshold, there is a factor of deterioration of overlay error in addition to reticle expansion / contraction correction. In step 616, the alignment processing conditions are further optimized.

Specifically, in step 616, the host 160 calculates the expansion / contraction correction in the X direction after optimizing the reticle R from the post-measurement results (superposition errors) Δξ _ij and Δζ _ij (i, j = 1 to 8). deviation amount corresponding to the amount E _{X0, k} and optimization prior to the difference between expansion and contraction correction amount E _{X0, k} in the X direction (scaling X variation), and expansion and contraction correction amount in the Y direction after optimization of the reticle R Is the difference between E _{Y0, k} and the Y-direction expansion / contraction correction amount E _{Y0, k} before optimization equivalent to the difference (scaling Y change) subtracted from the difference between the sample shots? Judge whether or not. If the variation between the residual sample shots is negligibly small (less than a predetermined threshold value), the host 160 uses the residual sample shot average to calculate the shot distortion correction amount (shot scaling, shot rotation, shot). The higher order correction coefficient and the like are obtained, and the result is transmitted to the main controller 50.

  If the variation in the residual sample shots cannot be ignored (greater than a predetermined threshold), the sample shots are not averaged, and the shot distortion correction amount (shot scaling, shot rotation, high-order correction coefficient, etc.) for each shot ) And the result is transmitted to the main controller 50.

  As an example of the shot distortion correction calculation model, the third-order calculation models (5a) and (5b) are shown below.

^{_{Δx = C SX30 Sx 3 + C}} SX21 Sx 2 Sy + C SX12 SxSy 2 + C SX03 Sy 3
+ C _SX20 Sx ² + C _SX11 SxSy + C _SX02 Sy ²
_{+ C SX10 Sx + C SX01 Sy} + C SX00 ... (5a)
Δy = C _SY30 Sx ³ + C _SY21 Sx ² Sy + C _SY12 SxSy ² + C _SY03 Sy ³
+ C _SY20 Sx ² + C _SY11 SxSy + C _SY02 Sy ²
+ C _SY10 Sx + C _SY01 Sy + C _SY00 (5b)

  When the optimization of the alignment process conditions is completed, the process of the subroutine at step 522 is terminated, and the process returns to step 524 of the main routine.

On the other hand, if the determination in step 614 is negative, that is, when the deviation between the predicted deformation amount E _{X0, k} and the measured deformation amount E _X is negligible (if the difference is below a predetermined threshold), Step 616 is skipped, the processing of the subroutine of step 522 is terminated, and the process returns to step 524 of the main routine.

  On the other hand, if the determination in step 608 is negative, that is, if the difference is equal to or smaller than a predetermined threshold, the process proceeds to step 616 to optimize the alignment processing conditions.

[Step 524]
In step 524, the value of the counter k is incremented by 1, and then the process returns to step 504. Thereafter, the processes in and after step 504 are repeated until the determination in step 514 is denied.

When the above steps are repeated and exposure of all wafers W _k (k = 1 to K) in the lot is completed, the determination in step 514 is denied and the process proceeds to step 530.

In step 530, after unloading the wafer W _K from the exposure apparatus 110 _n, and ends the series of processing of this routine (lot processing sequence).

  As described above in detail, according to the lithography system 100 according to the present embodiment, pre-measurement and post-measurement are performed for one wafer in a lot. In the pre-measurement, the first alignment mark formed together with the first pattern in the original process layer is detected, and the position error of the first pattern is obtained from the result. Here, a position error obtained from alignment measurement (multiple points in a shot) may be used instead of the preliminary measurement. In the post measurement, the second alignment mark formed together with the second pattern in the current process layer is detected, and the overlay error of the second pattern with respect to the first pattern is obtained from the result. Then, using these results, the reticle expansion / contraction correction parameters (saturation value, time constant) are optimized, and the second pattern is transferred onto the next wafer to be exposed using the optimized reticle expansion / contraction correction parameters. The Accordingly, even when the degree of deformation of the reticle is increased when the second pattern is transferred to the previous wafer, sufficient overlay accuracy (positioning accuracy) is obtained when the second pattern is transferred to the next wafer. It becomes possible.

  Further, according to the lithography system 100 according to the present embodiment, the reticle for correcting the alignment error of the second pattern resulting from the deformation of the reticle R when the overlay error obtained by the post measurement is out of the allowable range. When the parameters (saturation value and time constant) included in the expansion / contraction correction model are optimized, there is an alignment condition for correcting the residual when the reticle expansion / contraction correction model is applied to correct the alignment error of the second pattern. Calculated (alignment process conditions are optimized), a reticle expansion / contraction correction model with optimized saturation values and time constants is applied, and the next exposure target of a plurality of wafers according to the optimized alignment process conditions The second pattern is transferred so as to overlap the first pattern already formed in the plurality of shot areas arranged on the wafer. Therefore, even in this respect, even when the degree of deformation of the reticle is increased when the second pattern is transferred to the previous wafer, sufficient overlay accuracy (position is sufficient when the second pattern is transferred to the next wafer. Alignment accuracy) can be obtained.

  In the lithography system 100 of the present embodiment, the reticle expansion / contraction correction and the pre-measurement and post-measurement for each are performed each time the wafer in the lot is exposed. However, the present invention is not limited to this. In the case where the angle is moderate, the reticle expansion / contraction correction and the pre-measurement and post-measurement may be performed for each of a plurality of wafers. In addition to this, a threshold value for determining the degree of deviation between the actual expansion / contraction variation amount of the reticle R obtained from the measurement results of the pre-measurement and the post-measurement and the expected expansion / contraction correction amount obtained using the reticle expansion / contraction correction model is set. It is good to decide.

In addition, after the pre-measurement for the wafer W _k to be exposed by the overlay measurement device 130 is completed, the next exposure by the measurement device 130 is performed in parallel with the alignment measurement and exposure for the wafer W _k by the exposure device 110 _n. Prior measurement may be performed on the target wafer W _{k + 1} . Thereby, since the alignment measurement and exposure can be performed on the wafer W _{k + 1} immediately after the post-measurement on the wafer W _k after the exposure is completed, the throughput is improved. Alternatively, the position error of the first pattern may be obtained using the result of alignment measurement (multiple points in a shot) without performing preliminary measurement.

  In addition, although only one measurement apparatus 130 is introduced into the lithography system 100 of the present embodiment, a plurality of measurement apparatuses may be introduced. However, pre-measurement and post-measurement for one wafer are performed using the same measuring device.

In the above-described embodiment, the lot processing sequence corresponding to the flowcharts of FIGS. 5 and 6 is performed by the host 160. However, the present invention is not limited to this, and at least a part of the functions of the host 160 may 110 _n of the main control unit 50, may be provided to other control devices can, of course.

  In the above-described embodiment, the case where the present invention is applied to a dry type exposure apparatus that exposes the wafer W without using liquid (water) has been described. No. 99/49504, European Patent Application Publication No. 1,420,298, International Publication No. 2004/055803, US Pat. No. 6,952,253, etc. The present invention is also applied to an immersion exposure apparatus that forms an immersion space including an optical path of illumination light between the wafer and the wafer, and exposes the wafer with illumination light through the liquid in the projection optical system and immersion space. Can do.

  In the above embodiment, the case where the present invention is applied to a step-and-scan type scanning exposure apparatus has been described. However, the present invention is not limited to this, and the present invention is applied to a stationary exposure apparatus such as a stepper. Also good. The present invention can also be applied to a step-and-stitch type reduction projection exposure apparatus, a proximity type exposure apparatus, or a mirror projection aligner that combines shots. Further, as disclosed in, for example, US Pat. No. 6,590,634, US Pat. No. 5,969,441, US Pat. No. 6,208,407, etc. The present invention can also be applied to a multi-stage type exposure apparatus provided with a stage. In addition, as disclosed in, for example, US Patent Application Publication No. 2007/0127006, etc., an exposure including a measurement stage including a measurement member (for example, a reference mark and / or a sensor) separately from the wafer stage. The present invention can also be applied to an apparatus.

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

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

  In the above embodiment, it is needless to say that the illumination light IL of the exposure apparatus is not limited to light having a wavelength of 100 nm or more, and light having a wavelength of less than 100 nm may be used. For example, in recent years, in order to expose a pattern of 70 nm or less, EUV (Extreme Ultraviolet) light in a soft X-ray region (for example, a wavelength region of 5 to 15 nm) is generated using an SOR or a plasma laser as a light source, and its exposure wavelength Development of an EUV exposure apparatus using an all-reflection reduction optical system designed under (for example, 13.5 nm) and a reflective mask is underway. In this apparatus, since a configuration in which scanning exposure is performed by synchronously scanning the mask and the wafer using arc illumination is conceivable, the present invention can also be suitably applied to such an apparatus. In addition, the present invention can be applied to an exposure apparatus using a charged particle beam such as an electron beam or an ion beam.

  Further, as disclosed in, for example, US Pat. No. 6,611,316, two reticle patterns are synthesized on a wafer via a projection optical system, and one scan exposure is performed on one wafer. The present invention can also be applied to an exposure apparatus that performs double exposure of shots almost simultaneously.

  Note that the object on which the pattern is to be formed in the above embodiment (the object to be exposed to the energy beam) is not limited to the wafer, but other objects such as a glass plate, a ceramic substrate, a film member, or a mask blank. But it ’s okay.

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

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

  The exposure method of the present invention is suitable for accurately forming a pattern on an object. The device manufacturing method and the exposure system of the present invention are suitable for manufacturing an electronic device such as a semiconductor element or a liquid crystal display element.

100 ... lithography _{system, 110 1 ~110 N (110 n} ) ... exposure apparatus, 130 ... measuring device, 160 ... host computer, W ... wafer, R ... reticle.

Claims (25)

An exposure method for sequentially transferring a pattern formed on a mask onto a plurality of objects,
A plurality of first marks attached to at least a part of a plurality of partitioned areas arranged on one object among the plurality of objects are detected, and formed in the plurality of partitioned areas using the detection result A first step for determining a position error of the completed first pattern;
A plurality of second marks attached to at least a part of the plurality of partitioned areas onto which the second pattern is transferred so as to be superimposed on the first pattern are detected, and the second result for the first pattern is detected using the detection result. A second step of determining a pattern overlay error;
When the overlay error is outside the allowable range,
Mask expansion variation during exposure processing when the second pattern is formed by adding a correction amount during exposure processing to the sum of the position error in the first pattern and the overlay error in the second pattern Ask for quantity
Verify the accuracy of the mask stretch correction model for correcting this using the mask stretch variation amount ,
A third step of correcting the mask expansion / contraction correction parameter according to the verification result;
The first pattern already formed in a plurality of partitioned regions arranged on a next object among the plurality of objects by correcting the overlay error of the second pattern using the corrected mask expansion / contraction correction parameter. A fourth step of transferring the second pattern over the pattern;
An exposure method comprising: The exposure method according to claim 1 , wherein in the third step, a parameter included in the mask expansion / contraction correction model is optimized using the mask expansion / contraction variation amount. Wherein in the third step, if the reduction in the precision than the precision of the verification result of said mask stretching correction model are observed, exposure method according to claim 1 or 2 to modify the mask stretch correction parameter. Allowable deviation between the mask expansion / contraction variation amount obtained by adding the correction amount during the exposure process to the sum of the position error and the overlay error and the mask expansion / contraction correction amount obtained using the mask expansion / contraction correction model. The method according to any one of claims 1 to 3 , further comprising a step of correcting the overlay error using the shift and optimizing the alignment condition prior to the fourth step when the position is out of the range. The exposure method as described. A step of optimizing an alignment condition using the overlay error prior to the fourth step when the decrease in accuracy is not recognized from the verification result of the mask expansion / contraction correction accuracy in the third step; Furthermore, the exposure method as described in any one of Claims 1-4 further included. The exposure method according to claim 4 or 5 , wherein in the third step, the accuracy of the correction model is verified by further using the alignment condition. The alignment condition includes a design condition for a plurality of marks provided on the object, a detection condition for detecting the plurality of marks, and a process condition for processing the detection results of the plurality of marks. The exposure method according to any one of claims 4 to 6 , comprising at least one of a correction method for the alignment error. The exposure method according to claim 7 , wherein the design condition includes at least one of the number, arrangement, and shape of the plurality of marks. The detection condition is, the wavelength of the illumination light when illuminated with illumination light the plurality of marks, strength, size and shape of the illumination area, and from the claims 7 or comprises at least one of the phase difference 9. The exposure method according to 8 . 10. The exposure method according to claim 4 , wherein in the fourth step, the second pattern is sequentially transferred under the optimized alignment condition. The exposure method according to claim 1 , wherein in the fourth step, the alignment error derived from the magnification of the plurality of partitioned regions is corrected using the correction model. In the fourth step, a plurality of first marks attached to at least a part of the plurality of partitioned regions arranged on the next object are detected, and the second pattern is transferred using the detection result. The exposure method according to any one of claims 1 to 11 . The pattern is transferred onto the object via an optical system,
The exposure method according to any one of claims 1 to 12 , wherein in the fourth step, the alignment error is corrected by driving and controlling an optical element constituting the optical system. The pattern is transferred onto the object by relatively driving the mask and the object,
The exposure method according to claim 1 , wherein in the fourth step, the alignment error is corrected by controlling the relative drive. Wherein by repeating the first to fourth steps, an exposure method according to any one of claims 1 to 14 for sequentially transferring the second pattern to said plurality of the objects. The exposure method according to claim 15 , wherein the first and second steps are performed only on a predetermined number of objects according to the degree of the overlay error. An exposure method for sequentially transferring a pattern formed on a mask onto a plurality of objects,
A plurality of marks attached to at least a part of a plurality of partitioned areas on the object, onto which the second pattern is transferred over the first pattern, are detected, and the second result for the first pattern is detected using the detection result. A first step for determining a pattern overlay error;
When the overlay error is outside an allowable range, information on an alignment condition and an alignment result corresponding to the alignment condition is acquired, and the second derived from deformation of the mask on which the second pattern is formed. Position for correcting a residual when a parameter included in a correction model for correcting a pattern overlay error is optimized and the correction model after the optimization is applied to correct the overlay error of the second pattern A second step of calculating the matching conditions;
Applying the optimized correction model and applying the corrected pattern to the first pattern formed in a plurality of partitioned regions arranged on a next object among the plurality of objects according to the calculated alignment condition A third step of transferring the second pattern in an overlapping manner;
An exposure method comprising: Forming a pattern on a plurality of objects using the exposure method according to any one of claims 1 to 17 ;
Developing the object on which the pattern is formed;
A device manufacturing method including: At least one exposure apparatus for sequentially transferring a pattern formed on the mask onto a plurality of objects;
A plurality of first marks attached to at least a part of a plurality of partition regions arranged on one of the plurality of objects, the first mark detection system detecting a mark present on the object; A first measuring device that detects a mark using the first mark detection system, and obtains a position error of the first pattern formed in the plurality of partitioned regions based on the detection result;
A second mark detection system configured to detect a mark present on the object, wherein at least a part of the plurality of partitioned regions on the object on which the second pattern is transferred by the exposure apparatus so as to overlap the first pattern; A second measuring device that detects a plurality of second marks attached to the second pattern using the second mark detection system and obtains an overlay error of the second pattern with respect to the first pattern based on the detection result;
A host computer that collectively manages the exposure apparatus and the first and second measurement apparatuses;
With
When either the exposure apparatus or the host computer has the overlay error determined by the second measurement apparatus is outside an allowable range,
Add the correction amount during the exposure process to the sum of the position error in the first pattern and the overlay error in the second pattern,
Obtaining the mask expansion / contraction variation amount during the exposure process when the second pattern is formed,
Verify the accuracy of the mask stretch correction model for correcting this using the mask stretch variation amount ,
Modify (optimize) the mask stretch correction parameter according to the verification result,
The exposure apparatus corrects an overlay error of the second pattern according to an application result of the mask expansion / contraction correction parameter;
An exposure system for transferring the second pattern so as to overlap the first pattern formed in a plurality of partitioned regions arranged on a next object among the plurality of objects. The exposure system according to claim 19 , wherein the first mark detection system and the second mark detection system are the same mark detection system. 21. The exposure system according to claim 19 or 20 , wherein either the exposure apparatus or the host computer corrects the alignment error derived from the magnification of the plurality of partitioned regions in accordance with an application result of the correction model. The exposure apparatus includes a detection system that detects a mark existing on each of the plurality of objects, and at least a part of the plurality of partitioned regions arranged on the next object using the detection system. The attached first mark is detected, and based on the detection result, the second pattern is transferred so as to overlap the first pattern already formed in a plurality of partitioned areas arranged on the next object. The exposure system according to any one of claims 19 to 21 . The exposure system according to any one of claims 19 to 22 , wherein the exposure apparatus includes a correction system that corrects the alignment error. The exposure apparatus includes a plurality of lens elements, and includes an optical system that projects a pattern formed on the mask onto the object,
24. The exposure system according to claim 23 , wherein the correction system includes a lens driving device that drives at least a part of the plurality of lens elements. The exposure apparatus measures position information of a first moving body that moves while holding the mask, a second moving body that moves while holding each of the plurality of objects, and the first and second moving bodies. With a measuring system
The exposure system according to claim 23 or 24 , wherein the correction system corrects the alignment error by driving the first and second moving bodies based on a measurement result of the measurement system.

Images