JP5120691B2 - Mark detection method and apparatus, exposure method and apparatus, and device manufacturing method - Google Patents

Description

  The present invention relates to a mark detection technique for detecting a mark placed on an object such as a semiconductor wafer or a glass substrate, a position control technique for performing position control of the object using the mark detection technique, an exposure technique, and It relates to device manufacturing technology.

Conventionally, in a lithography process for manufacturing electronic devices (microdevices) such as semiconductor elements (integrated circuits, etc.) and liquid crystal display elements, a step-and-repeat type projection exposure apparatus (so-called stepper) or a step-and-scan type is used. An exposure apparatus such as a projection exposure apparatus (a so-called scanning stepper (also called a scanner)) is used.
For example, in a lithography process for manufacturing a semiconductor element, a multilayer circuit pattern is superimposed on a wafer to form a desired element. However, if the overlay accuracy between layers is poor, the semiconductor element exhibits predetermined circuit characteristics. Cannot be achieved and the yield decreases. For this reason, usually, a mark (alignment mark) is attached in advance to each of a plurality of shot areas on the wafer, and the position (coordinate value) of the mark on the stage coordinate system of the exposure apparatus is measured using an alignment system. Then, wafer alignment is performed to obtain the array coordinates of each shot area on the wafer from the measurement result. Thereafter, each shot area on the wafer is sequentially patterned based on the arrangement coordinate information of each shot area on the wafer and the known (measured) position information of a newly formed pattern (for example, a reticle pattern). The pattern is transferred to the shot area while being aligned with respect to.

As a method of wafer alignment, in consideration of throughput, by detecting alignment marks in only a few shot areas (also called sample shots or alignment shots) on the wafer and obtaining the regularity of the shot area arrangement, The global alignment for obtaining the array coordinates of the shot area is mainly used. Among them, in particular, enhanced global alignment (EGA) that calculates the arrangement of shot areas on a wafer with high accuracy by a statistical method has become the mainstream (see, for example, Patent Document 1).
JP-A 61-44429

  In the conventional wafer alignment, a plurality of predetermined alignment marks on a wafer are measured using one alignment system (an alignment system having one detection area), and the array coordinates of all shot areas are obtained based on the result. It was. Therefore, in order to increase the alignment accuracy, when the number of alignment marks to be measured is increased, the alignment marks are repeatedly moved and measured one by one into the detection region of the alignment system. There is a problem that the time required for the measurement becomes longer and the throughput of the exposure process is lowered.

In particular, recent wafers have increased in area and the number of shot areas on a single wafer has increased, so in order to increase alignment accuracy, it is required to measure as many alignment marks as efficiently as possible. Yes.
The present invention has been made under the circumstances described above, and an object of the present invention is to provide a mark detection technique that can detect a plurality of marks on an object such as a semiconductor wafer with high accuracy without reducing throughput as much as possible. To do.

  Another object of the present invention is to provide an exposure technique using the mark detection technique and a device manufacturing technique using the exposure technique.

The first mark detection method according to the present invention is a plurality of mark detection systems (AL1, AL2 _{1 to} AL2 ₄ ) having different detection areas in at least one axial direction (X direction), and at least different positions in the one axial direction. A mark detection method for detecting a mark on an object arranged at a first position out of a plurality of marks arranged on a reference member (46) in a specific positional relationship where positions in one axial direction are different from each other. Detecting a set of marks (M1, M2 ₁ ) with a corresponding set of mark detection systems (AL1, AL2 ₁ ) (step 306); and the first set of marks among the plurality of marks step one mark (M1) is to detect the common second pair of marks (M1, M2 _2), with a corresponding set of the mark detection system (AL1, AL2 ₂₎ and (step 30 Obtaining the positional relationship information of the plurality of mark detection systems based on the detection result of the corresponding mark of the mark detection system and the specific positional relationship of the plurality of marks (step 308); It is what has.

A first mark detection apparatus according to the present invention is a plurality of mark detection systems (AL1, AL2 _{1 to} AL2 ₄ ) having different detection areas in at least one axial direction, and are arranged at positions different from each other in at least one axial direction. A mark detection device for detecting a mark on an object, a reference member (46) having a plurality of marks arranged at specific positional relationships different from each other in the position in one axial direction; and a plurality of members arranged on the reference member Among the plurality of marks, a first set of marks is detected by a corresponding set of mark detection systems, and the first set of marks and one mark among the plurality of marks are shared by a second A set of marks is detected through a corresponding set of the mark detection system, the detection result of the corresponding mark of the mark detection system, and the specific positional relationship of the plurality of marks Those comprising; based, the control unit for obtaining information on the positional relationship of the plurality of mark detection systems and (20, 20a).

The present invention also describes the following invention.
The second mark detection method according to the present invention is a plurality of mark detection systems (AL1, AL2 1 to AL2 4) having different detection areas in at least one axial direction (X direction), and arranged at positions different from each other at least in the one axial direction. A mark detection method for detecting a mark on an object (W), wherein marks (WMA to WME) at different positions on the object are moved to the detection areas of the plurality of mark detection systems, respectively, A step of detecting a mark (step 315); a step of measuring detection information of each of the plurality of mark detection systems and defocus information of the detection region while gradually changing at least one of the height and inclination angle of the object. (Step 316); information on the in-focus state obtained from the detection information of each of the plurality of mark detection systems and the detection thereof And a defocus information band, obtaining a correction information of the defocus information (step 317); and it has a.

A second mark detection apparatus according to the present invention is a plurality of mark detection systems (AL1, AL2 _{1 to} AL2 ₄ ) having different detection areas in at least one axial direction, and are arranged at positions different from each other in at least one axial direction. A mark detection apparatus for detecting a mark on an object, the attitude control mechanism (WST) for controlling at least one of the height and the inclination angle of the object; and defocus information of the detection region of the plurality of mark detection systems A defocus information measurement system (6A to 6E) for obtaining the image, and a control device (20, 132). The control device has different positions on the object in the detection areas of the plurality of mark detection systems, respectively. The mark (WMA to WME) is moved, the mark is detected using the plurality of mark detection systems, and the mark is detected via the attitude control device. While gradually changing at least one of the body height and inclination angle, the detection information of each of the plurality of mark detection systems and the defocus information by the defocus information measurement system are obtained, and the detection of each of the plurality of mark detection systems The correction information of the defocus information is obtained from the focus state information obtained from the information and the defocus information of the detection area.

The third mark detection method according to the present invention is a mark detection system (AL1, AL2 _{1 to} AL2 ₄ ) having a plurality of detection regions whose positions in at least one axial direction (X direction) are different from each other. A mark detection method for detecting marks on an object arranged at positions different from each other in the axial direction, wherein a reference member (46) in which a plurality of marks are arranged in a specific positional relationship in which the positions in one axial direction are different from each other, Positioned in two of the plurality of detection regions in a posture inclined with respect to the one axis, the reference member and the two detection regions are moved relative to each other in the direction of the one axis, and within the two detection regions. mark (M1, M2 ₁₎ substantially simultaneously detected (step 306), relating to the arrangement of a plurality of marks of the two results of detection of the mark in the detection region and the reference in the member The positional relationship information of the two detection regions is obtained from the information on the specific positional relationship of the two, and the two detection regions and the mark on the object are moved relative to each other in the one axis direction without relative movement. The mark (WMG, WMJ) on the object is detected substantially simultaneously (step 320), the result of detecting the mark on the object in the two detection areas substantially simultaneously, and the positional relationship between the two detection areas The position information of each mark on the object detected in each of the two detection areas is obtained from the information.

The third mark detection apparatus according to the present invention includes a plurality of detection regions (AL1f, AL2 ₁ f to AL2 ₄ f) having positions different from each other in at least one axis direction, and are arranged at positions different from each other at least in the one axis direction. A mark detection device for detecting marks on an object substantially simultaneously, wherein a reference member (46) in which a plurality of marks are arranged in a specific positional relationship in which the positions in one axial direction are different from each other, and the reference member, The two driving devices (MST) positioned in two of the plurality of detection regions in a posture inclined with respect to the one axis, the reference member, and the two detection regions without relative movement in the direction of the one axis. Based on the result of detecting the marks in the detection area substantially simultaneously and the information on the specific positional relationship regarding the arrangement of the marks in the reference member, the two detections are performed. And an arithmetic unit (20a) for obtaining positional relationship information of the area, and the two detection areas and the mark on the object are moved on the object in the two detection areas without relatively moving in the one axis direction. Are detected in each of the two detection areas from the result of detecting the marks on the object substantially simultaneously in the two detection areas and the positional relationship information of the two detection areas. The position information of each mark on the object is obtained.

A fourth mark detection method according to the present invention is a mark detection system (AL1, AL2 _{1 to} AL2 ₄ ) including a plurality of detection regions having positions different from each other in at least one axial direction (X direction). A mark detection method for detecting marks on an object arranged at different positions with respect to an axial direction, wherein the object is positioned in two of the plurality of detection areas, and the height direction position of the object and While gradually changing at least one of the inclination of the object, the first set of marks (WMC, WMD) located on each of the two detection areas is detected (steps 315, 316), and the two detection areas are detected. Each detected result is evaluated according to a predetermined evaluation standard, and the object is tilted based on the evaluation result at a position in the height direction based on the evaluation result. And location, a second set of marks differ from its first set of marks on the object (WMH, WMI) and detects in two detection regions thereof (step 320).

A fifth mark detection method according to the present invention is a mark detection system (AL1, AL2 _{1 to} AL2 ₄ ) having a plurality of detection regions whose positions in at least one axial direction (X direction) are different from each other. A mark detection method for detecting marks on an object arranged at positions different from each other with respect to the axial direction, wherein a plurality of the reference members (46) on which marks are formed are gradually changed in the height direction. A mark (M1, M2 ₁ ) on the reference member located in each of the detection areas is detected (step 302), each of the results detected in the plurality of detection areas is evaluated according to a predetermined evaluation criterion, and the object is Then, it is tilted based on the result of the evaluation at a position in the height direction based on the result of the evaluation, and is arranged in two of the plurality of detection regions (step 320). Of the detection area in the mark on the object (WMH, WMI) is used to detect substantially simultaneously.

  In addition, although the reference numerals in parentheses attached to the predetermined elements of the present invention correspond to members in the drawings showing an embodiment of the present invention, each reference numeral of the present invention is provided for easy understanding of the present invention. The elements are merely illustrative, and the present invention is not limited to the configuration of the embodiment.

  According to the present invention, a plurality of mark detection systems having different detection areas in at least one axial direction (or a mark detection system having a plurality of detection areas having different positions in at least one axial direction) is used. Since a plurality of different marks can be detected simultaneously by a plurality of mark detection systems (or two detection areas), a plurality of marks on the object can be detected efficiently.

Furthermore, according to the first mark detection method or apparatus of the present invention, the position of the reference member is detected by detecting a plurality (one set) of marks on the reference member with a corresponding plurality (one set) of mark detection systems. Even if fluctuates, the positional relationship between the plurality of mark detection systems can be measured with high accuracy, and the subsequent measurement accuracy is improved.
In addition, according to the second mark detection method or apparatus of the present invention, since a plurality of marks on the object are detected in parallel by a plurality of mark detection systems and defocus information is corrected, defocusing is efficiently performed. The information can be corrected, and the accuracy of focusing the marks on the subsequent objects is improved, thereby improving the measurement accuracy.

In addition, according to the third mark detection method or apparatus of the present invention, it is possible to improve focusing accuracy by detecting two marks on the reference member in two corresponding detection areas. Therefore, the positional relationship between the plurality of detection areas of the mark detection system can be measured with high accuracy, and the subsequent measurement accuracy is improved.
According to the fourth mark detection method of the present invention, two marks on an object are detected in two corresponding detection areas, and after defocus information is corrected, mark detection is performed in the focused state as it is. be able to. Therefore, a decrease in throughput based on the operation for correcting the defocus information is suppressed, and the focusing accuracy of the mark on the object thereafter is improved, thereby improving the measurement accuracy.

  Further, according to the fifth mark detection method of the present invention, it is possible to improve the focusing accuracy using the mark of the reference member, and to detect the mark by detecting the two marks on the object in the two detection areas. At the same time, it can be measured with high accuracy in a focused state.

Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of an exposure apparatus 100 according to the present embodiment. The exposure apparatus 100 is a so-called scanning stepper as a step-and-scan projection exposure apparatus (scanning exposure apparatus). As will be described later, in the present embodiment, the projection optical system PL is provided. In the following description, the Z-axis is taken in parallel to the optical axis AX of the projection optical system PL, and the reticle and wafer are aligned in a plane perpendicular to the Z-axis. The Y-axis is taken in the direction in which the image is relatively scanned, the X-axis is taken in the direction perpendicular to the Z-axis and the Y-axis, and the rotation (tilt) directions around the X-axis, Y-axis, and Z-axis are θx, θy, and θz, respectively. The direction is described.

  In FIG. 1, an exposure apparatus 100 includes an illumination system 10, a reticle stage RST that holds a reticle R illuminated by illumination light (exposure light) IL for exposure from the illumination system 10, and illumination light emitted from the reticle R. A projection unit PU including a projection optical system PL for projecting IL onto the wafer W, a stage device 50 having a wafer stage WST and a measurement stage MST, and a control system thereof are provided. Wafer W is placed on wafer stage WST.

The illumination system 10 includes a light source, an optical integrator (fly eye lens, rod integrator (inner surface), as disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-313250 (corresponding US Patent Application Publication No. 2003/0025890). And an illumination optical system having a reticle blind and the like (all not shown). The illumination system 10 illuminates the slit-shaped illumination area IAR on the reticle R defined by the reticle blind with illumination light IL with a substantially uniform illuminance. As the illumination light IL, for example, ArF excimer laser light (wavelength 193 nm) is used. Illumination light includes KrF excimer laser light (wavelength 247 nm), F ₂ laser light (wavelength 157 nm), harmonics of a YAG laser, harmonics of a solid-state laser (semiconductor laser, etc.), or bright lines (i-line) of a mercury lamp. Etc.) can also be used.

  On reticle stage RST, reticle R on which a circuit pattern or the like is formed on its pattern surface (lower surface) is fixed, for example, by vacuum suction. The reticle stage RST can be driven minutely in the XY plane by the reticle stage drive system 11 of FIG. 7 including a linear motor, for example, and can be driven at a scanning speed specified in the scanning direction (Y direction). Yes.

  Position information (including position information in the X direction, Y direction, and rotation information in the θz direction) in the movement plane of the reticle stage RST in FIG. 1 is transferred to the movable mirror 15 (stage by the reticle interferometer 116 made of a laser interferometer. For example, it may be detected with a resolution of about 0.5 to 0.1 nm through a reflection surface obtained by mirror-finishing the end surface of each other. The measurement value of reticle interferometer 116 is sent to main controller 20 in FIG. Main controller 20 calculates positions of reticle stage RST in at least the X direction, the Y direction, and the θz direction based on the measurement value of reticle interferometer 116, and controls reticle stage drive system 11 based on the calculation result. Thus, the position and speed of reticle stage RST are controlled.

  In FIG. 1, the projection unit PU disposed below the reticle stage RST includes a lens barrel 40 and a projection optical system PL having a plurality of optical elements held in the lens barrel 40 in a predetermined positional relationship. . As the projection optical system PL, for example, a refractive optical system including a plurality of lens elements arranged along the optical axis AX is used. The projection optical system PL is, for example, telecentric on both sides and has a predetermined projection magnification β (for example, a reduction magnification such as 1/4, 1/5, or 1/8). When the illumination area IAR is illuminated by the illumination light IL from the illumination system 10, the image of the circuit pattern of the reticle R in the illumination area IAR is projected via the projection optical system PL by the illumination light IL that has passed through the reticle R. It is formed in an exposure area IA (an area conjugate to the illumination area IAR) on one shot area of W. In the wafer W of this example, for example, a resist (photoresist) that is a photosensitive agent (photosensitive layer) is applied to a surface of a disk-shaped semiconductor wafer having a diameter of about 200 mm to 300 mm with a predetermined thickness (for example, about 200 nm). Including things. In each shot area of the wafer W of this example, a predetermined single layer or a plurality of layers of circuit patterns and corresponding alignment marks (wafer marks) are formed by the pattern forming process so far.

The exposure apparatus 100 performs exposure using a liquid immersion method. In this case, in order to avoid an increase in the size of the projection optical system, a catadioptric system including a mirror and a lens may be used as the projection optical system PL.
Further, in the exposure apparatus 100, the lower end of the lens barrel 40 that holds the tip lens 191 that is an optical element on the most image plane side (wafer W side) constituting the projection optical system PL is used to perform exposure using the liquid immersion method. A nozzle unit 32 constituting a part of the local liquid immersion device 8 is provided so as to surround the part periphery.

  In FIG. 1, the nozzle unit 32 has a supply port that can supply the exposure liquid Lq and a recovery port that can recover the liquid Lq. A porous member (mesh) is disposed at the recovery port. The lower surface of the nozzle unit that can face the surface of the wafer W includes a lower surface of the porous member and a flat surface disposed so as to surround an opening for allowing the illumination light IL to pass therethrough. Further, the supply port is connected to a liquid supply device 186 (see FIG. 7) capable of delivering the liquid Lq via a supply flow path formed inside the nozzle unit 32 and a supply pipe 31A. The recovery port is connected to a liquid recovery device 189 (see FIG. 7) capable of recovering at least the liquid Lq via a recovery flow path and a recovery pipe 31B formed inside the nozzle unit 32.

  The liquid supply device 186 includes a liquid tank, a pressure pump, a temperature control device, a flow rate control valve for controlling supply / stop of the liquid to the supply pipe 31A, etc. The liquid Lq can be delivered. The liquid recovery device 189 includes a liquid tank, a suction pump, and a flow rate control valve for controlling recovery / stop of the liquid via the recovery pipe 31B, and can recover the liquid Lq. Note that the liquid tank, the pressurization (suction) pump, the temperature control device, the control valve, and the like do not have to be all provided in the exposure apparatus 100, and at least a part thereof, such as a factory where the exposure apparatus 100 is installed It can be replaced by equipment.

  The operations of the liquid supply device 186 and the liquid recovery device 189 in FIG. 7 are controlled by the main controller 20. The exposure liquid Lq sent from the liquid supply device 186 in FIG. 7 flows through the supply pipe 31A and the supply flow path of the nozzle unit 32 in FIG. 1, and then is supplied from the supply port to the optical path space of the illumination light IL. Is done. Further, the liquid Lq recovered from the recovery port by driving the liquid recovery device 189 of FIG. 7 flows through the recovery flow path of the nozzle unit 32 of FIG. 1 and then passes through the recovery pipe 31B to the liquid recovery device 189. To be recovered. The main controller 20 in FIG. 7 performs the liquid supply operation from the supply port of the nozzle unit 32 and the liquid recovery operation by the recovery port of the nozzle unit 32 in parallel, so that the tip lens 191 and the wafer W in FIG. The liquid immersion space of the liquid Lq is formed so that the liquid immersion region 14 (see FIG. 4) including the optical path space of the illumination light IL between the liquid Lq is filled with the liquid Lq.

  Returning to FIG. 1, the stage apparatus 50 includes an interferometer including a wafer stage WST and a measurement stage MST disposed above the base board 12, and Y-axis interferometers 16 and 18 that measure positional information of these stages WST and MST. A system 118 (see FIG. 7), an encoder system (to be described later) used for measuring position information of wafer stage WST at the time of exposure, and a stage drive system for driving stages WST, MST and a Z / leveling mechanism (to be described later) 124 (see FIG. 7) and the like.

  On the bottom surfaces of wafer stage WST and measurement stage MST, non-contact bearings (not shown), for example, air pads constituting vacuum preload type aerostatic bearings are provided at a plurality of locations. Wafer stage WST and measurement stage MST are supported in a non-contact manner above base plate 12 through a clearance of about several μm by the static pressure of pressurized air ejected from the air pads toward the upper surface of base plate 12. ing. The stages WST and MST can be driven in a two-dimensional direction independently of the Y direction and the X direction by the stage drive system 124 of FIG.

  More specifically, on the floor surface, as shown in the plan view of FIG. 2, a pair of Y-axis stators extending in the Y direction on one side and the other side in the X direction across the base board 12. 86 and 87 are arranged, respectively. The Y-axis stators 86 and 87 are configured by, for example, a magnetic pole unit containing a permanent magnet group composed of a plurality of pairs of N-pole magnets and S-pole magnets arranged alternately at predetermined intervals along the Y direction. . The Y-axis stators 86 and 87 are provided with two Y-axis movers 82 and 84 and 83 and 85 in a non-contact state. That is, a total of four Y-axis movers 82, 84 and 83, 85 are inserted into the internal space of the U-shaped Y-axis stators 86 and 87 in the XZ cross section, and the corresponding Y-axis The stators 86 and 87 are supported in a non-contact manner through an air pad (not shown) with a clearance of about several μm, for example. Each of the Y-axis movers 82, 84, 83, 85 is configured by an armature unit that incorporates armature coils arranged at predetermined intervals along the Y direction, for example. That is, in the present embodiment, the moving-coil type Y-axis linear motor is constituted by the Y-axis movers 82 and 84 formed of armature units and the Y-axis stator 86 formed of a magnetic pole unit. Similarly, the Y-axis movers 83 and 85 and the Y-axis stator 87 constitute moving coil type Y-axis linear motors, respectively. In the following, each of the four Y-axis linear motors will be appropriately referred to as Y-axis linear motors 82, 84, 83, and 85 using the same reference numerals as the respective movers 82, 84, 83, and 85. And

  Among the four Y-axis linear motors, the movers 82 and 83 of the two Y-axis linear motors 82 and 83 are respectively fixed to one end and the other end of the X-axis stator 80 extending in the X direction. . Further, the movers 84 and 85 of the remaining two Y-axis linear motors 84 and 85 are fixed to one end and the other end of an X-axis stator 81 extending in the X direction. Accordingly, the X-axis stators 80 and 81 are driven along the Y-axis by the pair of Y-axis linear motors 82, 83, and 84, 85, respectively.

Each of the X-axis stators 80 and 81 is constituted by an armature unit that incorporates armature coils arranged at predetermined intervals along the X direction, for example.
One X-axis stator 81 is provided in an inserted state in an opening (not shown) formed in a stage main body 91 (see FIG. 1) constituting part of wafer stage WST. Inside the opening of the stage body 91, for example, a magnetic pole unit having a permanent magnet group composed of a plurality of pairs of N-pole magnets and S-pole magnets arranged alternately at predetermined intervals along the X direction is provided. ing. The magnetic pole unit and the X-axis stator 81 constitute a moving magnet type X-axis linear motor that drives the stage main body 91 in the X direction. Similarly, the other X-axis stator 80 is provided in an inserted state in an opening formed in the stage main body 92 constituting the measurement stage MST. Inside the opening of the stage main body 92, a magnetic pole unit similar to the wafer stage WST side (stage main body 91 side) is provided. The magnetic pole unit and the X-axis stator 80 constitute a moving magnet type X-axis linear motor that drives the measurement stage MST in the X direction.

  In the present embodiment, each of the linear motors constituting the stage drive system 124 is controlled by the main controller 20 shown in FIG. Each linear motor is not limited to either a moving magnet type or a moving coil type, and can be appropriately selected as necessary. Note that the yaw (rotation in the θz direction) of wafer stage WST (and measurement stage MST) can be controlled by making the thrust generated by the pair of Y-axis linear motors 84 and 85 (and 82 and 83) slightly different. Is possible.

  Wafer stage WST in FIG. 1 is provided in stage body 91 described above, wafer table WTB mounted on stage body 91, and stage body 91, and in the Z direction, θx direction, and stage body 91. and a Z-leveling mechanism that relatively finely drives the wafer table WTB (wafer W) in the θy direction. The Z / leveling mechanism includes, for example, a mechanism including a voice coil motor that applies displacement in the Z direction at three locations and sensors that measure the displacement in the Z direction at the three locations.

On wafer table WTB, a wafer holder (not shown) for holding wafer W by vacuum suction or the like is provided. Although the wafer holder may be formed integrally with wafer table WTB, in this embodiment, the wafer holder and wafer table WTB are separately configured, and the wafer holder is fixed in the recess of wafer table WTB by, for example, vacuum suction. In addition, the upper surface of wafer table WTB has a surface (liquid repellent surface) that has been subjected to a liquid repellent treatment with respect to liquid Lq and is substantially flush with the surface of the wafer placed on the wafer holder, and has an outer shape ( A plate (liquid repellent plate) 28 having a rectangular outline and a circular opening that is slightly larger than the wafer holder (wafer mounting region) is provided at the center thereof. The plate 28 is made of a material having a low coefficient of thermal expansion, such as glass, glass ceramics, or ceramics (Shot Corporation's Zerodur (trade name), Al ₂ O _3, TiC, or the like). The liquid repellent film is formed of a fluorine resin material such as tetrafluoroethylene (Teflon (registered trademark)), an acrylic resin material, or a silicon resin material.

  Further, as shown in the plan view of wafer table WTB (wafer stage WST) in FIG. 5A, plate 28 surrounds a first liquid repellent region 28a that surrounds a circular opening and has a rectangular outer shape (contour). A rectangular frame-shaped (annular) second liquid repellent area 28b disposed around the one liquid repellent area 28a. The first liquid repellent area 28a is formed, for example, at least part of the liquid immersion area 14 (see FIG. 4) that protrudes from the wafer surface during the exposure operation, and the second liquid repellent area 28b is used for an encoder system described later. A scale is formed. It should be noted that at least a part of the surface of the plate 28 may not be flush with the surface of the wafer, that is, it may have a different height. Further, the plate 28 may be a single plate, but in the present embodiment, a plurality of plates, for example, first and second liquid repellent plates corresponding to the first and second liquid repellent areas 28a and 28b, respectively, are combined. .

  In this case, the illumination light IL is irradiated to the inner first liquid repellent region 28a, whereas the illumination light IL is hardly irradiated to the outer second liquid repellent region 28b. In view of this, in the present embodiment, the surface of the first liquid repellent region 28a is provided with a water repellent coat that is sufficiently resistant to the illumination light IL (in this case, light in the vacuum ultraviolet region). The second liquid repellent area 28b is provided with a water repellent coat on its surface that is less resistant to the illumination light IL than the first liquid repellent area 28a.

  Further, as is apparent from FIG. 5A, a rectangular notch is formed in the central portion in the X direction at the end portion on the + Y direction side of the first liquid repellent region 28a. A measurement plate 30 is embedded in a rectangular space surrounded by the liquid repellent region 28b (inside the cutout). At the center of the measurement plate 30 in the longitudinal direction (on the center line LL of the wafer table WTB), a reference mark FM for baseline measurement is formed, and on one side and the other side of the reference mark in the X direction, A pair of aerial image measurement slit patterns (slit-shaped measurement patterns) SL is formed in a symmetrical arrangement with respect to the center of the reference mark FM. As each slit pattern SL, for example, an L-shaped slit pattern having sides along the Y direction and the X direction, or two linear slit patterns extending in the X axis and the Y direction, respectively, may be used. it can.

  Then, inside the wafer stage WST below each of the slit patterns SL, as shown in FIG. 5B, a light transmission system 36 including an optical system including an objective lens, a mirror, a relay lens, and the like is housed. An L-shaped housing is attached in a partially embedded state in a state of penetrating a part of the inside of the stage main body 91 from the wafer table WTB. Although not shown, a pair of light transmission systems 36 are provided corresponding to the pair of aerial image measurement slit patterns SL. The light transmission system 36 guides the illumination light IL transmitted through the aerial image measurement slit pattern SL along the L-shaped path and emits it in the Y direction.

Further, on the upper surface of the second liquid repellent region 28b, a large number of lattice lines 37 and 38 are directly formed at a predetermined pitch along each of the four sides. More specifically, Y scales 39Y ₁ and 39Y ₂ are formed in regions on both sides in the X direction of the second liquid repellent region 28b. Each of the Y scales 39Y ₁ and 39Y ₂ is formed, for example, by forming lattice lines 38 having the X direction as a longitudinal direction along a direction (Y direction) parallel to the Y axis at a predetermined pitch. And a reflection type grating (for example, a phase type diffraction grating).

Similarly, X scales 39X ₁ and 39X ₂ are respectively formed in regions on both sides in the Y direction of the second liquid repellent region 28b. Each of the X scales 39X ₁ and 39X ₂ is formed, for example, by forming lattice lines 37 having a longitudinal direction in the Y direction along a direction (X direction) parallel to the X axis at a predetermined pitch. And a reflection type grating (for example, a phase type diffraction grating).

As each of the scales _{39Y 1, 39Y 2, 39X 1} , 39X 2, which diffraction grating of the reflection type by the surface for example a hologram or the like of the second liquid repellent area 28b is created are used. In this case, each scale is provided with a grid made up of narrow slits or grooves as scales at a predetermined interval (pitch). The type of the diffraction grating used for each scale is not limited, and may be not only those in which grooves or the like are mechanically formed, but may also be created by baking interference fringes on a photosensitive resin, for example. . However, each scale is formed by, for example, engraving the scale of the diffraction grating on a thin glass plate at a pitch between 138 nm and 4 μm, for example, 1 μm pitch. These scales are covered with the liquid repellent film (water repellent film) described above. In FIG. 5A, for the convenience of illustration, the pitch of the lattice is shown to be much wider than the actual pitch. The same applies to the other drawings.

  Thus, in this embodiment, since the 2nd liquid repellent area | region 28b itself comprises a scale, we decided to use a low thermal expansion glass plate as a material of the 2nd liquid repellent area | region 28b. However, the present invention is not limited to this, and a scale member made of a low thermal expansion glass plate with a lattice formed thereon is placed on the upper surface of wafer table WTB by, for example, a leaf spring (or vacuum suction) so that local expansion and contraction does not occur. In this case, a water-repellent plate having the same water-repellent coating on the entire surface may be used in place of the plate 28.

  The -Y end surface and -X end surface of wafer table WTB are mirror-finished to form reflecting surfaces 17a and 17b shown in FIG. The Y-axis interferometer 16 and the X-axis interferometer 126 (see FIG. 2) of the interferometer system 118 (see FIG. 7) project interferometer beams (measurement beams) on these reflecting surfaces 17a and 17b, respectively. Each reflected light is received. Interferometers 16 and 126 measure the displacement of each reflecting surface from the reference position (for example, the reference mirror disposed on the side surface of projection unit PU), that is, the position information of wafer stage WST in the XY plane. Is supplied to the main controller 20. In the present embodiment, a multi-axis interferometer having a plurality of optical axes is used as the Y-axis interferometer 16 and the X-axis interferometer 126, and the main control is performed based on the measurement values of these interferometers 16 and 126. In addition to the position of wafer table WTB in the X and Y directions, apparatus 20 can also measure θx direction rotation information (pitching), θy direction rotation information (rolling), and θz direction rotation information (yawing).

  However, in the present embodiment, position information (including rotation information in the θz direction) in the XY plane of wafer stage WST (wafer table WTB) mainly includes the Y scale, X scale, and the like described later. The measurement values of the interferometers 16 and 126 are used supplementarily when correcting (calibrating) long-term fluctuations in the measurement values of the encoder system (for example, due to temporal deformation of the scale). . The Y-axis interferometer 16 is used for measuring the position in the Y direction of the wafer table WTB in the vicinity of an unloading position, which will be described later, and the loading position, for wafer replacement. Also, for example, in the movement of wafer stage WST between the loading operation and the alignment operation and / or between the exposure operation and the unloading operation, the measurement information of interferometer system 118, that is, the direction of 5 degrees of freedom (X direction) , Y direction, θx, θy, and θz directions). Note that the Y-axis interferometer 16, the X-axis interferometer 126, the Y-axis interferometer 18 for the measurement stage MST described later, and the X-axis interferometer 130 of the interferometer system 118 are, for example, a main frame that holds the projection unit PU. Is provided.

  Further, in the present embodiment, the position information of wafer stage WST measured by interferometer system 118 is not used in the exposure operation and alignment operation described later, and mainly the calibration operation of the encoder system (that is, the calibration of the measurement value). However, the measurement information of the interferometer system 118 (that is, at least one of position information in the direction of 5 degrees of freedom) may be used in, for example, an exposure operation and / or an alignment operation. In this case, the measurement information of the interferometer system 118 is also supplied to the alignment calculation system 20a. In the present embodiment, the encoder system measures position information of wafer stage WST in three degrees of freedom, that is, in the X axis, Y axis, and θz directions. Therefore, in an exposure operation or the like, out of the measurement information of the interferometer system 118, a direction different from the measurement direction (X direction, Y direction, and θz direction) of the position information of the wafer stage WST by the encoder system, for example, the θx direction and / or Only position information regarding the θy direction may be used, or in addition to position information regarding the different directions, a position regarding the same direction as the measurement direction of the encoder system (ie, at least one of the X direction, the Y direction, and the θz direction). Information may be used. Further, interferometer system 118 may be capable of measuring position information of wafer stage WST in the Z direction. In this case, position information in the Z direction may be used in the exposure operation or the like.

  The measurement stage MST of FIG. 1 is configured by mounting a flat measurement table MTB and a later-described CD bar 46 (see FIG. 6A) on a stage main body 92. The stage main body 92 incorporates a Z-leveling mechanism (for example, a mechanism including three voice coil motors) that controls the position of the measurement table MTB and the CD bar 46 in the Z direction and the inclination angle in the θx direction and the θy direction. It is. The measurement table MTB and the stage main body 92 are provided with various measurement members. As the measurement member, for example, as shown in FIGS. 2 and 6A, an illuminance unevenness sensor 94 having a pinhole-shaped light receiving unit, a spatial image of a pattern projected by the projection optical system PL (projection) An aerial image measuring device 96 for measuring the image), a wavefront aberration measuring device 98, and the like are employed.

In the present embodiment, it is used for the measurement using the illumination light IL corresponding to the immersion exposure for exposing the wafer W with the illumination light IL through the projection optical system PL and the liquid (water) Lq. The illuminance unevenness sensor 94 (and the illuminance monitor), the aerial image measuring instrument 96, and the wavefront aberration measuring instrument 98 described above receive the illumination light IL through the projection optical system PL and water.
As shown in FIG. 6B, a frame-shaped attachment member 42 is fixed to the end surface on the −Y direction side of the stage main body 92 of the measurement stage MST. Further, on the end surface on the −Y direction side of the stage main body 92, an arrangement is provided in the vicinity of the center position in the X direction inside the opening of the mounting member 42 so as to face the pair of light transmission systems 36 in FIG. A pair of light receiving systems 44 are fixed. Each light receiving system 44 includes an optical system such as a relay lens, a light receiving element, such as a photomultiplier tube, and a housing for housing these. As can be seen from FIGS. 5B and 6B and the description so far, in this embodiment, wafer stage WST and measurement stage MST are close to each other within a predetermined distance in the Y direction (contact state). , The illumination light IL transmitted through each slit pattern SL of the measurement plate 30 of the wafer stage WST is guided by the above-described light transmission systems 36 and received by the light receiving elements of the respective light reception systems 44 of the measurement stage MST. . That is, a space similar to that disclosed in Japanese Patent Laid-Open No. 2002-14005 (corresponding US Patent Application Publication No. 2002/0041377) or the like is measured by the measurement plate 30, the light transmission system 36, and the light reception system 44. An image measuring device 45 (see FIG. 7) is configured.

On the attachment member 42 in FIG. 6B, a confidential bar (hereinafter abbreviated as “CD bar”) 46 as a reference member made of a rod-shaped member having a rectangular cross section is extended in the X direction. The CD bar 46 is kinematically supported on the mounting member 42 of the measurement stage MST by a full kinematic mount structure.
Since the CD bar 46 is a prototype (measurement standard), glass ceramics having a low thermal expansion coefficient, for example, Zerodure (trade name) manufactured by Schott is used as the material. The upper surface (front surface) of the CD bar 46 is set to have a flatness as high as that of a so-called reference flat plate. In addition, a reference grating (for example, a diffraction grating) 52 having a periodic direction in the Y direction is provided near one end and the other end of the CD bar 46 in the longitudinal direction, as shown in FIG. Is formed. The pair of reference gratings 52 are formed in a symmetrical arrangement with respect to the center of the CD bar 46 in the X direction, that is, the center line CL, with a predetermined distance (L).

A plurality of reference marks M are formed on the upper surface of the CD bar 46 in the arrangement as shown in FIG. The plurality of reference marks M are formed in an array of, for example, three rows in the Y direction, and the plurality of marks in each row are formed with a predetermined distance from each other in the X direction. As each reference mark M, a two-dimensional mark having a size detectable by a primary alignment system and a secondary alignment system, which will be described later, is used. The shape (configuration) of the reference mark M may be different from the reference mark FM shown in FIG. In the present embodiment, the reference mark M for the primary alignment system has the same configuration as the reference mark FM and the same configuration as the alignment mark of the wafer W. On the other hand, since the detection area of the secondary alignment system is movable within a predetermined range in the X direction as will be described later, the reference marks M for the secondary alignment system are elongated in the X direction at a predetermined pitch in the X direction and the Y direction as an example. It is a dimension mark. Information on the shapes and positional relationships (intervals, etc.) of the plurality of reference marks M is stored in an alignment calculation system 20 a connected to the main controller 20.
In the present embodiment, the surface of the CD bar 46 and the surface of the measurement table MTB (which may include the above-described measurement member) are also covered with a liquid repellent film (water repellent film).

  As shown in FIG. 2, reflection surfaces 19a and 19b similar to the wafer table WTB described above are also formed on the + Y end surface and the −X end surface of the measurement table MTB. The Y-axis interferometer 18 and the X-axis interferometer 130 of the interferometer system 118 (see FIG. 7) project interferometer beams (measurement beams) on these reflecting surfaces 19a and 19b and receive the reflected lights. Thus, the displacement of each reflecting surface from the reference position, that is, the position information of the measurement stage MST (for example, including at least position information in the X direction and Y direction and rotation information in the θz direction) is measured. Is supplied to the main controller 20.

  Meanwhile, as shown in FIG. 2, stopper mechanisms 48A and 48B are provided at both ends of the X-axis stators 81 and 80 in the X direction. The stopper mechanisms 48A and 48B are provided on the X axis stator 81 at positions facing the shock absorbers 47A and 47B as shock absorbers made of, for example, an oil damper, and the shock absorbers 47A and 47B of the X axis stator 80. And the shutters 49A and 49B for opening and closing the openings 51A and 51B. Opening / closing states of the openings 51A, 51B by the shutters 49A, 49B are detected by an opening / closing sensor (see FIG. 7) 101 provided in the vicinity of the shutters 49A, 49B, and the detection results are sent to the main controller 20.

Here, the action of the stopper mechanisms 48A and 48B will be described by taking the stopper mechanism 48A as a representative.
In FIG. 2, when the shutter 49A closes the opening 51A, the shock absorber 47A and the shutter 49A come into contact (contact) even when the X-axis stator 81 and the X-axis stator 80 approach each other. As a result, the X-axis stators 80 and 81 can no longer approach each other. On the other hand, when the shutter 49A is opened and the opening 51A is opened, when the X-axis stators 81 and 80 approach each other, at least a part of the distal end portion of the shock absorber 47A can enter the opening 51A. The shaft stators 81 and 80 can be brought close to each other. As a result, wafer table WTB and measurement table MTB (CD bar 46) can be brought into contact (or close to a distance of about 300 μm).

  In FIG. 2, interval detection sensors 43A and 43C and collision detection sensors 43B and 43D are provided on the −Y side of both ends of the X-axis stator 80, and on the + Y side of both ends of the X-axis stator 81. , Elongated plate-like members 41A and 41B are projected in the Y direction. The interval detection sensors 43A and 43C are made of, for example, a transmissive photosensor (for example, a sensor made of an LED-phototransistor), and the X-axis stator 80 and the X-axis stator 81 come close to each other between the interval detection sensors 43A. Since the plate-like member 41A is inserted and the amount of received light is reduced, it can be detected that the distance between the X-axis stators 80 and 81 is equal to or less than a predetermined distance.

  The collision detection sensors 43B and 43D are photoelectric sensors similar to the interval detection sensors 43A and 43C, but are further arranged in the back thereof. According to the collision detection sensors 43B and 43D, when the X-axis stators 81 and 80 are further approached and the wafer table WTB and the CD bar 46 (measurement table MTB) are in contact with each other (or a stage close to a distance of about 300 μm). Since the upper half of the plate-like member 41A is positioned between the sensors, the main controller 20 detects that the amount of light received by the sensor is zero, so that both tables are in contact (or about 300 μm). Can be detected.

In the exposure apparatus 100 of this embodiment, illustration is omitted in FIG. 1 from the viewpoint of avoiding complication of the drawing, but actually, as shown in FIG. 4, the center of the projection unit PU (of the projection optical system PL). The detection center is located at a predetermined distance from the optical axis AX to the −Y side on a straight line LV that passes through the optical axis AX (in this embodiment, also coincides with the center of the exposure area IA described above) and is parallel to the Y axis. A primary alignment system AL1 is arranged. The primary alignment system AL1 is fixed to a main frame (not shown). Secondary alignment systems AL2 ₁ , AL2 ₂ and secondary alignment systems AL2 ₃ , AL2 _{4 in} which detection centers are arranged almost symmetrically with respect to the straight line LV on one side and the other side of the X direction across the primary alignment system AL1. And are provided respectively. That is, the five alignment systems AL1, AL2 _{1 to} AL2 ₄ have their detection regions (detection centers) arranged at different positions in the X direction, that is, along the X direction.

Each secondary alignment system AL2 _n (n = 1~4), as representatively shown by secondary alignment system AL2 _4, times in a predetermined angle range in clockwise and counter-clockwise in FIG. 4 around the rotational center O The movable arm 56 _n (n = 1 to 4) is fixed to the tip (rotating end). In the present embodiment, each secondary alignment system AL2 _n includes a part thereof (for example, at least an optical system that irradiates the detection region with the alignment light and guides the light generated from the target mark in the detection region to the light receiving element). It is fixed to the arm 56 _n and the remaining part is provided on the main frame (not shown). Each of the secondary alignment systems AL2 _{1 to} AL2 ₄ rotates about the rotation center O, thereby adjusting the position (X position) in the X direction of the detection region.

That is, the secondary alignment systems AL2 _{1 to} AL2 ₄ have their detection areas (or detection centers) movable independently in the X direction. In the present embodiment, the X position of the detection region of the secondary alignment systems AL2 _{1 to} AL2 ₄ is adjusted by rotating the arm. However, the present invention is not limited to this, for example, the optical system at the tip of the secondary alignment systems AL2 _{1 to} AL2 ₄ is moved in the X direction parallel to the Y axis by a linear motor or the like, and the change in the optical path length due to the movement is not shown. You may make it cancel by the optical system. According to this parallel movement method, the detection area of each secondary alignment system moves parallel to the X axis. Furthermore, as can be driven secondary alignment systems AL2 ₁ AL24 ₄ of the tip portion of the optical system (or the whole optical system of the secondary alignment systems AL2 ₁ ~AL2 ₄₎ X direction linear motor system or the like, independently in the Y direction Also good.

Further, at least one of the detection regions of the secondary alignment systems AL2 _{1 to} AL2 ₄ may be movable not only in the X direction but also in the Y direction. Since each optical system of each secondary alignment system AL2 _n is moved by the arm 56 _n , a part of the secondary alignment system AL2 _n is fixed to the arm 56 _n by a sensor (not shown) such as an interferometer or an encoder. The position information of the optical system can be measured. This sensor may only measure position information in the X direction of the detection region of the secondary alignment system AL2 _n , but other directions, for example, the Y direction and / or the rotation direction (including at least one of the θx and θy directions). The position information may be measurable.

A vacuum pad 58 _n (n = 1 to 4) composed of a differential exhaust type air bearing is provided on the upper surface of each arm 56 _n . Further, the arm 56 _n can be rotated in accordance with an instruction from the main controller 20 by a rotation drive mechanism 60 _n (n = 1 to 4, see FIG. 7) including, for example, a motor or the like. After adjusting the rotation of arm 56 _n , main controller 20 operates each vacuum pad 58 _n to adsorb and fix each arm 56 _n to a main frame (not shown). Thereby, the state after adjusting the rotation angle of each arm 56 _n , that is, the desired positional relationship between the primary alignment system AL1 and the four secondary alignment systems AL2 _{1 to} AL2 ₄ is maintained. 7 simultaneously sets the X position of the detection region of secondary alignment system AL2 _n and the X positions of a plurality of alignment marks to be detected on the wafer near the detection center in those detection regions. To control.

A magnetic material may be fixed to a part of the measurement frame 21 facing the arm 56 _n and an electromagnet may be used instead of the vacuum pad 58 _n .
In the present embodiment, for example, an image processing type FIA (Field Image Alignment) system is used as each of the primary alignment system AL1 and the four secondary alignment systems AL2 _{1 to} AL2 ₄ . In this FIA system, an object mark formed on a light-receiving surface by irradiating a detection mark with a broadband detection light beam from a halogen lamp or a xenon lamp that does not sensitize a resist on a wafer, and reflected light from the inspection mark These images are picked up using an image pickup device (CCD type or CMOS type), and the image pickup signals are output. In this case, the position of the image of the test mark is detected with reference to the position of a predetermined pixel in the image sensor. Instead, an index mark is provided in the FIA system, and the position of the image of the index mark is used as a reference. As an example, an image of the test mark may be detected. Information on the amount of deviation from the reference position of the image of the test mark obtained via the alignment systems AL1 and AL2 _{1 to} AL2 ₄ is supplied to the main controller 20 in FIG.

FIG. 3A conceptually shows a schematic configuration of the five-eye alignment systems AL1 and AL2 _{1 to} AL2 ₄ . In FIG. 3A, alignment systems AL1 and AL2 _{1 to} AL2 ₄ are respectively connected to fiducial marks M1, M2 ₁ , M2 ₂ , M2 ₃ , M2 ₄ on CD bar 46 in FIG. 6A (FIG. 6A). Is detected) corresponding to any one of the reference marks M. In FIG. 3A, the primary alignment system AL1 includes a first objective lens system 5a that receives reflected light from the test mark, a beam splitter 5b that branches the reflected light, an aperture stop (not shown), It includes a second objective lens system 5c that condenses the reflected light from the first objective lens system 5a to form an enlarged image of the test mark, and a two-dimensional image sensor 5d that captures the image. Actually, for example, a beam splitter (not shown) for guiding illumination light from a light source (not shown) to the test mark is provided between the first objective lens system 5c and the beam splitter 5b. Further, the field of view on the test surface conjugate with the imaging surface of the image sensor 5d is the detection area AL1f of the primary alignment system AL1.

The secondary alignment systems AL2 _{1 to} AL2 ₄ are similar in basic configuration to the primary alignment system AL1, and include an objective lens system that forms an enlarged image of the test mark, and a two-dimensional image sensor 5d that captures the image. Is included. The visual field on the test surface conjugate with the imaging surface of each imaging device of the secondary alignment systems AL2 _{1 to} AL2 ₄ is the detection region AL ₁ f to AL2 ₄ f. Further, as an example, a point on the test surface corresponding to the pixel (origin) at the center of the image sensor 5d of the primary alignment system AL1 becomes the detection center of the primary alignment system AL1. Further, a mark located at a position that is separated from the detection center of the primary alignment system AL1 by a predetermined variable distance (secondary base line described later) in the X direction is detected by the image sensor 5d of the secondary alignment systems AL2 _{1 to} AL2 _4. If there is, the center of the mark becomes the detection center of each secondary alignment system AL2 _{1 to} AL2 ₄ .

Imaging signals from the imaging devices 5d of the alignment systems AL1 and AL2 _{1 to} AL2 ₄ are supplied to detection signal processing units 131A, 131B, 131C, 131D, and 131E, respectively. In the detection signal processing units 131A to 131E, the image pickup signals of the respective image pickup devices 5d are accumulated in a predetermined range in a direction corresponding to the Y direction and the X direction on the surface to be measured, and are periodically in the X direction and the Y direction, respectively. Imaging signals SX and SY of the mark image are generated, and the imaging signals SX and SY are supplied to the offset correction unit 132.

Further, the detection signal processing units 131A to 131E slice the respective image pickup signals SX and SY with, for example, a predetermined threshold value to obtain the amount of positional deviation in the X direction and the Y direction with respect to the detection center of the corresponding mark. The quantity information is supplied to the alignment calculation system 20a of FIG. In the alignment calculation system 20a, the coordinate in the stage coordinate system (X, Y) of the test mark is obtained by adding each positional deviation amount to the coordinates of the detection center of each alignment system AL2 _{1 to} AL2 ₄ obtained in advance. The value can be determined.

The detection region AL2 ₁ f~AL2 ₄ f of secondary alignment systems AL2 ₁ AL24 ₄ is movable within a predetermined range in the X direction. Thus, for example, when the entire secondary alignment systems AL2 ₁ AL24 ₄ to move, since the optical path length within the secondary alignment systems AL2 ₁ AL24 ₄ is not changed, the secondary alignment systems AL2 ₁ AL24 ₄ The configuration may be the same as that of the primary alignment system AL1. On the other hand, for example, when only the optical system such as the tip of the secondary alignment systems AL _{1 to} AL2 ₄ is movable, it is necessary to incorporate an optical system for canceling the change in the optical path length thereafter.

In addition, the best focus positions of the alignment systems AL1 and AL2 _{1 to} AL2 ₄ are actually three imaging signals SX and SY corresponding to the image of the test mark obtained from each imaging element 5d as shown below. This is the position in the Z direction (Z position or focus position) of the surface to be tested when it meets any of the evaluation criteria A, B, and C.
(A) When the contrast of the imaging signal is the highest. For example, as shown in FIG. 3C, the best focus position is when the contrast of the imaging signal SY corresponding to the mark image in the Y direction is highest as shown by the dotted line. If the best focus position is slightly different between the imaging signals SX and SY, the average value may be used as the best focus position.

(B) When the rate of change (rise) of the image signal in the horizontal direction is the steepest.
(C) When the weighted average of evaluation criteria A and B is the highest.
Which of these evaluation criteria is applied may differ, for example, when the test mark is a mark on the CD bar 46 and when it is an alignment mark (hereinafter referred to as a wafer mark) on the wafer W. . Different evaluation criteria may be applied depending on whether the test mark is an amplitude mark or a phase mark. In the present embodiment, as an example, the Z position of the test surface when the contrast of the imaging signal of the image of the test mark of the evaluation criterion A is the highest is set as the best focus position. Note that the evaluation standard B may be applied as an evaluation standard for a wafer mark that is an uneven mark (phase mark).

In any of the above evaluation criteria, in order to determine the best focus position, it is necessary to scan the test surface in the Z direction in a state where the image of the test mark is captured by the image sensor 5d. However, if a certain amount of scanning operation in the Z direction is executed each time one mark is detected, the throughput is lowered. Therefore, in order to measure the defocus amount that is the amount of deviation in the Z direction between the test surface and the best focus position, each of the alignment systems AL1 and AL2 _{1 to} AL2 ₄ has an autofocus system (hereinafter referred to as AF) having the same configuration. 6A, 6B, 6C, 6D, and 6E are mounted. By this AF system, it is possible to determine how much the mark is shifted to the plus side or minus side in the Z direction, and to quickly move the mark in the Z direction by a necessary amount. The AF systems 6A to 6E for the alignment system are not shown in FIG.

  As an example, the AF system 6A includes a pupil division mirror 6b that divides and reflects light branched (or reflected) by the beam splitter 5b (or a partial reflection mirror or the like) of the primary alignment system AL1 in the vicinity of the pupil plane. A condensing lens system 6c for condensing the light from the mirror 6b to form two magnified images of the pattern on the surface to be examined, and a one-dimensional line sensor (two-dimensional image sensor for capturing the two magnified images) 6d) may be included. In practice, the AF system 6A incorporates an optical member (not shown) that transmits light that has passed through a predetermined pattern (such as a slit pattern) illuminated by illumination light from a light source (not shown) to the beam splitter 5b side. Two images of the predetermined pattern are formed on the line sensor 6d. The detection signal of the line sensor 6d is supplied to the detection signal processing unit 131A. In this case, when the test surface is displaced in the Z direction, the interval (difference in shift amount) between the two imaging positions of the pattern on the line sensor 6d changes, and thus the detection signal processing unit 131A corresponds to the interval. A focus signal FS indicated by a solid line in FIG. 3B is supplied to the offset correction unit 132.

The other AF systems 6B to 6E are configured in the same manner as the AF system 6A, and the detection signal processing units 131B to 131E to which the detection signals from the line sensors of the AF systems 6B to 6E are supplied are secondary alignment systems AL2 _{1 to} AL2 respectively. A focus signal corresponding to the defocus amount of the test surface with respect to the best focus position with respect to the _fourth image sensor 5d is supplied to the offset correction unit 132. A more detailed configuration of the autofocus system that can be used as the AF systems 6A to 6E is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-335971. As the AF systems 6A to 6E, for example, an autofocus system using a light beam on a substantially half surface of the pupil surface as disclosed in JP-A-7-321030 can be used.

The offset correction unit 132 supplies information on the defocus amount for each of the alignment systems AL1 and AL2 _{1 to} AL2 ₄ obtained by multiplying these focus signals by a coefficient obtained in advance to the main controller 20. Main controller 20 uses the information on the defocus amount to measure wafer stage WST or measurement so that the test surface is arranged at the best focus position of alignment systems AL1 and AL2 _{1 to} AL2 ₄ as described later. The Z leveling mechanism in the stage MST is driven to level the wafer W or the CD bar 46.

Further, during calibration of focus signals obtained via AF systems 6A to 6E, which will be described later, the offset correction unit 132 actually uses the focus signals FS from the detection signal processing units 131A to 131E of the AF systems 6A to 6E. The offset FSOF1 and the like are obtained so as to become 0 at the obtained best focus position Zf1 and the like, and supplied to the detection signal processing units 131A to 131E. The detection signal processing units 131 </ b> A to 131 </ b> E supply the focus signal corrected by adding the offset to the original focus signal to the offset correction unit 132. After changing the position in the X direction of the detection area of the secondary alignment systems AL2 _{1 to} AL2 ₄ of the present embodiment, the defocus amount of the focus signal obtained via the AF systems 6B to 6E is different from the actual defocus amount. Since there is a fear, it is preferable to calibrate the focus signal.

  The alignment system is not limited to the FIA system. For example, the target mark is irradiated with coherent detection light to detect scattered light or diffracted light generated from the target mark, or 2 generated from the target mark. Of course, it is possible to use an alignment sensor that detects two diffracted lights (for example, diffracted lights of the same order or diffracted in the same direction) by interference alone or in appropriate combination. Also in these cases, an autofocus system similar to the AF systems 6A to 6E that measures the amount of deviation from the best focus position of the test surface is provided.

In the present embodiment, since five alignment systems AL1, AL2 _{1 to} AL2 ₄ are provided, alignment can be performed efficiently. However, the number of alignment systems is not limited to five, and may be two or more and four or less, or six or more, or may be an even number instead of an odd number.
In the exposure apparatus 100 of the present embodiment, as shown in FIG. 4, the four head units 62 </ b> A to 62 </ b> D of the encoder system are arranged so as to surround the nozzle unit 32 from four directions. A plurality of Y heads 64 and X heads 66 constituting these head units 62A to 62D are fixed to the bottom surface of a main frame (not shown) as shown by a two-dot chain line in FIG.

In FIG. 4, head units 62A and 62C are arranged at predetermined intervals on a straight line LH that passes through the optical axis AX of the projection optical system PL along the X direction on the + X side and −X side of the projection unit PU, respectively, and is parallel to the X axis. A plurality of (here, six) Y heads 64 are provided. Y head 64 measures the position in the Y direction (Y position) of wafer stage WST (wafer table WTB) using Y scale 39Y ₁ or 39Y ₂ in FIG. Further, a plurality of head units 62B and 62D are arranged at substantially predetermined intervals on a straight line LV passing through the optical axis AX along the Y direction on the + Y side and the −Y side of the projection unit PU, respectively, and parallel to the Y axis. Here, seven and eleven X heads 66 (however, in FIG. 4, three of the eleven, which overlap with the primary alignment system AL1 are not shown) are provided. The X head 66 measures the position (X position) in the X direction of the wafer stage WST (wafer table WTB) using the X scale 39X ₁ or 39X ₂ in FIG.

Therefore, the head units 62A and 62C in FIG. 4 use the Y scales 39Y ₁ and 39Y ₂ in FIG. 5A, respectively, to measure the Y position of the wafer stage WST (wafer table WTB) (multiple eyes (here 6). Eye) Y-axis linear encoders (hereinafter abbreviated as Y encoder as appropriate) 70A and 70C (see FIG. 7). Each of the Y encoders 70A and 70C includes a switching control unit that switches the measurement values of the plurality of Y heads 64 (details will be described later). Here, the interval between adjacent Y heads 64 (that is, measurement beams emitted from the Y head 64) included in the head units 62A and 62C is the width of the Y scales 39Y ₁ and 39Y _{2 in} the X direction (more accurately, Is set narrower than the length of the grid line 38).

Further, head units 62B and 62D are using basically each X scales 39X ₁ and 39X ₂ described above, to measure the X-position of wafer stage WST (wafer table WTB), multiview (here, 7 eyes and Eleven eye) X-axis linear encoders (hereinafter abbreviated as X encoder as appropriate) 70B and 70D (see FIG. 7) are configured. Each of the X encoders 70B and 70D includes a switching control unit that switches the measurement values of the plurality of X heads 66. In the present embodiment, for example, two X heads 66 out of eleven X heads 66 included in the head unit 62D may face the X scales 39X ₁ and 39X ₂ at the time of alignment described later. . In this case, X linear encoders 70B and 70D are configured by the X scales 39X ₁ and 39X ₂ and the X head 66 facing the X scales 39X ₁ and 39X ₂ .

The distance between adjacent X heads 66 (measurement beams) included in each of the head units 62B and 62D is larger than the width in the Y direction of the X scales 39X ₁ and 39X ₂ (more precisely, the length of the grid line 37). It is set narrowly.
Furthermore, the secondary alignment systems AL2 ₁ on the -X side of Figure 4, the + X side of secondary alignment system AL2 _4, substantially against parallel straight line and the detection center in the X axis passing through the detection center of primary alignment system AL1 symmetry Y heads 64y ₁ and 64y ₂ in which detection points are arranged are respectively provided. The distance between the Y heads 64y ₁ and 64y ₂ is set to be approximately equal to the distance L described above (the distance in the Y direction of the reference grating 52 in FIG. 6A). The Y heads 64y ₁ and 64y ₂ face the Y scales 39Y ₂ and 39Y ₁ in the state shown in FIG. 4 where the center of the wafer W on the wafer stage WST is on the straight line LV. In case of an alignment operation and the like to be described later, Y heads 64y opposite to _1, 64y ₂ Y scales 39Y _2, 39Y ₁ are placed respectively, the Y heads 64y _1, 64y ₂ (i.e., they Y heads 64y _1, 64y ₂ ), the Y position (and the angle in the θz direction) of wafer stage WST is measured.

In the present embodiment, the pair of reference grids 52 and the Y heads 64y ₁ and 64y ₂ of the CD bar 46 in FIG. The Y position of the CD bar 46 is measured at the position of each reference grating 52 by the reference grating 52 facing the heads 64y ₁ and 64y ₂ . Hereinafter, linear encoders configured by Y heads 64y ₁ and 64y ₂ respectively facing the reference grating 52 are referred to as Y encoders 70E and 70F (see FIG. 7).

The measurement values of the six encoders 70A to 70F described above are supplied to the main controller 20 and the alignment calculation system 20a, and the main controller 20 is based on the measurement values of the encoders 70A to 70D in the XY plane of the wafer table WTB. And the rotation of the CD bar 46 in the θz direction is controlled based on the measured values of the Y encoders 70E and 70F.
In the exposure apparatus 100 of this embodiment, as shown in FIG. 4, for example, Japanese Patent Laid-Open No. 6-283403 (corresponding US Pat. No. 5,448,332) comprising an irradiation system 90a and a light receiving system 90b. Are provided with a multi-point focal position detection system (hereinafter abbreviated as a multi-point AF system) of an oblique incidence system having the same configuration as that disclosed in the above. In the present embodiment, as an example, the irradiation system 90a is disposed on the −Y side of the −X end portion of the head unit 62C described above, and in the state facing this, the −Y side of the + X end portion of the head unit 62A described above. The light receiving system 90b is arranged in the front.

A plurality of detection points of the multipoint AF system (90a, 90b) in FIG. 4 are arranged at predetermined intervals along the X direction on the surface to be detected. In the present embodiment, for example, they are arranged in a row matrix of 1 row and M columns (M is the total number of detection points) or 2 rows and N columns (N is 1/2 of the total number of detection points). In FIG. 4, a plurality of detection points irradiated with the detection beams are not shown individually, but are shown as elongated detection areas AF extending in the X direction between the irradiation system 90a and the light receiving system 90b. Since this detection area AF has a length in the X direction set to be approximately the same as the diameter of the wafer W, the position information in the Z direction can be obtained on almost the entire surface of the wafer W by scanning the wafer W once in the Y direction. (Surface position information) can be measured. The detection area AF is arranged between the liquid immersion area 14 (exposure area IA) and the detection areas of the alignment systems (AL1, AL2 _{1 to} AL2 ₄ ) in the Y direction. The detection operation can be performed in parallel between the AF system and the alignment system. The multipoint AF system may be provided in the main frame that holds the projection unit PU, but may be supported via another support member.

In addition, although the some detection point shall be arrange | positioned by 1 row M column or 2 rows N columns, the number of rows and / or the number of columns is not restricted to this.
The exposure apparatus 100 of the present embodiment is symmetric with respect to the straight line LV in the vicinity of detection points located at both ends of a plurality of detection points of the multipoint AF system (90a, 90b), that is, in the vicinity of both ends of the detection area AF. Each surface position sensor (hereinafter abbreviated as a Z sensor) 72a, 72b, 72c, 72d for Z position measurement is provided. These Z sensors 72a to 72d are fixed to the lower surface of the main frame, for example. Z sensors 72a to 72d irradiate wafer table WTB with light from above, receive the reflected light, and measure position information in the Z direction orthogonal to the XY plane of wafer table WTB surface at the light irradiation point. For example, an optical displacement sensor (CD pickup type sensor) configured like an optical pickup used in a CD drive device or the like is used.

Further, the above-described head unit 62C is arranged along two straight lines parallel to the straight line LH, which are located on one side and the other side across the straight line LH in the X direction connecting the plurality of Y heads 64, and at predetermined intervals. A plurality of (here, 6 each, 12 in total) Z sensors 74 _{i, j} (i = 1, 2, j = 1, 2,..., 6) are provided. In this case, the paired Z sensors 74 _{1, j} and 74 _{2, j} are disposed symmetrically with respect to the straight line LH. Further, a plurality of pairs (here, six pairs) of Z sensors 74 _{1, j} , 742 _{, j} and a plurality of Y heads 64 are alternately arranged in the X direction. As each Z sensor 74 _{i, j} , for example, a CD pickup type sensor similar to the aforementioned Z sensors 72 a to 72 d is used.

Here, 1 Z sensor 74 of each pair in a symmetrical _{position, j,} 74 2, interval _j with respect to straight line LH, Z sensor 72c described above, are set to the same interval as the 72d. Further, the pair of Z sensors 74 _1,4 , 74 _2,4 are located on the same straight line parallel to the Y direction as the Z sensors 72a, 72b.
Further, the head unit 62A described above has a plurality of, in this case, twelve Z sensors 76 _{p, q} (p = 1, 2) arranged symmetrically with the plurality of Z sensors 74 _{i, j} with respect to the straight line LV. Q = 1, 2,..., 6). As each Z sensor 76 _{p, q} , for example, a CD pickup type sensor similar to the Z sensors 72a to 72d described above is used. Further, a pair of Z sensors 76 _1,3, 76 _2,3 is positioned in the Z sensors 72c, the same Y-direction on a straight line and 72d. The Z sensors 74 _{i, j} and 76 _{p, q} are fixed to the bottom surface of the measurement frame 21.

  In FIG. 4, illustration of the measurement stage MST is omitted, and an immersion region 14 formed by water Lq held between the measurement stage MST and the tip lens 191 is shown. In FIG. 4, reference numeral 78 denotes dry air whose temperature is adjusted to a predetermined temperature in the vicinity of the beam path of the multipoint AF system (90a, 90b), as indicated by the white arrow in FIG. The local air-conditioning system which ventilates by a down flow is shown. Reference sign UP indicates an unload position where the wafer is unloaded on the wafer table WTB, and reference sign LP indicates a loading position where the wafer is loaded on the wafer table WTB. In the present embodiment, the unload position UP and the loading position LP are set symmetrically with respect to the straight line LV. Note that the unload position UP and the loading position LP may be the same position.

  FIG. 7 shows the main configuration of the control system of the exposure apparatus 100. This control system is mainly configured of a main control device 20 composed of a microcomputer (or a workstation) for overall control of the entire apparatus. In FIG. 7, various sensors provided on the measurement stage MST such as the uneven illuminance sensor 94, the aerial image measuring device 96, and the wavefront aberration measuring device 98 are collectively shown as a sensor group 9.

The exposure apparatus 100 of the present embodiment configured as described above employs the X scale and Y scale arrangement on the wafer table WTB as described above and the X head and Y head arrangement as described above. As illustrated in FIGS. 8A and 8B, in the effective stroke range of wafer stage WST (that is, in the present embodiment, the range moved for alignment and exposure operations), The X scales 39X ₁ and 39X ₂ and the head units 62B and 62D (X head 66) face each other, and the Y scales 39Y ₁ and 39Y ₂ and the head units 62A and 62C (Y head 64) or the Y heads 64y ₁ and 64y. _{The two} are facing each other. In FIGS. 8A and 8B, the head facing the corresponding X scale or Y scale is circled.

Therefore, main controller 20 controls each motor constituting stage drive system 124 based on at least three measurement values of encoders 70A to 70D in the above-described effective stroke range of wafer stage WST, so that the wafer is controlled. Position information in the XY plane of stage WST (including rotation information in the θz direction) can be controlled with high accuracy. Since the influence of the air fluctuations on the measurement values of the encoders 70A to 70D is negligibly small compared to the interferometer, the short-term stability of the measurement values caused by the air fluctuation is much better than that of the interferometer. In the present embodiment, the sizes of the head units 62B, 62D, 62A, and 62C (for example, the number of heads and the number of heads) are determined according to the effective stroke range of the wafer stage WST and the size of the scale (ie, the diffraction grating formation range). / Or interval). Accordingly, in the effective stroke range of wafer stage WST, all four scales 39X ₁ , 39X ₂ , 39Y ₁ , 39Y ₂ are opposed to head units 62B, 62D, 62A, 62C, respectively. It does not have to face the unit.

For example, one of the X scales 39X ₁ and 39X ₂ and / or one of the Y scales 39Y ₁ and 39Y ₂ may be detached from the head unit. When one of the X scales 39X ₁ and 39X ₂ or one of the Y scales 39Y ₁ and 39Y ₂ deviates from the head unit, the three scales face the head unit in the effective stroke range of the wafer stage WST. Position information in the X axis, Y axis, and θz directions can always be measured. Further, when one of the X scales 39X ₁ and 39X ₂ and one of the Y scales 39Y ₁ and 39Y ₂ are out of the head unit, the _two scales face the head unit in the effective stroke range of the wafer stage WST. Position information in the θz direction of WST cannot always be measured, but position information in the X axis and Y direction can always be measured. In this case, position control of wafer stage WST may be performed using the position information of wafer stage WST in the θz direction measured by interferometer system 118 in combination.

In addition, when the wafer stage WST is driven in the X direction as indicated by a white arrow in FIG. 8A, the Y head 64 that measures the position of the wafer stage WST in the Y direction is indicated by the arrow in the figure. As indicated by e ₁ and e ₂ , the adjacent Y heads 64 are sequentially switched. For example, the Y head 64 surrounded by a solid circle is switched to the Y head 64 surrounded by a dotted circle. Therefore, the measurement value is taken over by the switching control unit in the Y encoders 70A and 70C in FIG. 7 before and after the switching. That is, in this embodiment, in order to smoothly switch the Y head 64 and take over the measurement value, as described above, the interval between the adjacent Y heads 64 included in the head units 62A and 62C is set to the Y scale 39Y ₁ , it is obtained by set narrower than the width of the X direction 39Y _2.

In the present embodiment, as described above, the interval between adjacent X heads 66 included in the head units 62B and 62D is set to be narrower than the width of the X scales 39X ₁ and 39X _{2 in} the Y direction. Accordingly, as described above, when the wafer stage WST is driven in the Y direction as indicated by the white arrow in FIG. 8B, the X head 66 that measures the position of the wafer stage WST in the X direction is The X heads 66 are sequentially switched to the adjacent X head 66 (for example, the X head 66 surrounded by the solid circle is switched to the X head 66 surrounded by the dotted circle), and before and after the switching, in the X encoders 70B and 70D of FIG. The switching value is taken over by the switching control unit.

In addition, the Y head 64 of the encoders 70A to 70F coaxially irradiates a pair of laser beams to the corresponding Y scales 39Y ₁ and 39Y ₂ and a pair of diffracted lights generated from these scales. And a light receiving system that detects the interference light as combined light. Furthermore, the Y head 64 also incorporates an optical system that detects interference light having a phase difference of 90 °. By interpolating using the two-phase detection signals, the Y head 64 is ½ of the scale pitch. Displacement measurement can be performed with considerably finer resolution. The X heads 66 of the encoders 70A to 70F are similarly configured.

Hereinafter, in the exposure apparatus 100 of FIG. 1 of the present embodiment, an example of the operation when sequentially exposing the pattern image of the reticle R on one lot of wafers under the control of the main controller 20 of FIG. This will be described with reference to FIGS. 17 and 18.
First, in step 301 of FIG. 17, the reticle R is loaded onto the reticle stage RST of FIG. 1, and the main controller 20 determines the illumination conditions of the reticle R, the numerical aperture of the projection optical system PL, etc. from the exposure data file (not shown). The exposure conditions are read and the illumination system 10 and the like are set. Further, main controller 20 reads information on the shot arrangement of the wafer to be exposed from the exposure data file, and from this shot arrangement information, the arrangement pitch in the X direction of the shot area on the wafer, that is, each shot on the wafer. An X-direction interval (design interval) between the wafer marks attached to the region is obtained.

The wafer shot arrangement is set as shown in FIG. 13C as an example, and an alignment shot (sample shot) consisting of 16 shot areas distinguished from, for example, black selected from all shot areas on the wafer W. ) The wafer mark attached to the AS is measured by the alignment systems AL1, AL2 _{1 to} AL2 ₄ . In this case, the alignment shot AS on the wafer W has three alignment shots, five alignment shots, five alignment shots, and three alignment shots in the order of the width of four shot regions in the X direction from the + Y direction. Consists of. Although the wafer mark may be formed in the shot area, in the present embodiment, the wafer mark is formed on a street line between the shot areas.

Further, it is assumed that the arrangement of alignment systems AL1, AL2 _{1 to} AL2 _{4 in} the previous process is in the state shown in FIG. The intervals in the X direction of the detection centers of the secondary alignment systems AL2 ₁ , AL2 ₂ , AL2 ₃ , AL2 ₄ with respect to the detection center of the primary alignment system AL1, that is, secondary base lines SBL1, SBL2, SBL3, SBL4 are shown in FIG. As described above, the secondary alignment systems AL2 _{1 to} AL2 ₄ are driven and fixed so as to be a predetermined integer multiple of the interval between the wafer marks in the X direction. As an example, the initial values of the secondary baselines SBL1, SBL2, SBL3, and SBL4 are 8 times, 4 times, 4 times, and 8 times the interval in the X direction of the wafer mark (see FIG. 13C). Information on these values is also supplied to the alignment calculation system 20a. As a result, the primary alignment system AL1 and the secondary alignment systems AL2 _{1 to} AL2 ₄ are adjusted in position in the X direction in accordance with the arrangement of the wafer marks to be measured on the alignment shot AS on the wafer W. . At this stage, a setting error is included in the interval in the X direction between the detection centers of the secondary alignment systems AL2 _{1 to} AL2 ₄ .

In the next step 302, in order to perform the alignment systems AL1, AL2 ₁ AL24 calibration AF system 6A~6E for ₄ in FIG. 3 (A), the state of FIG. 2 (however, the wafer W is being placed by driving the measuring stage MST from no), moving the plurality of reference marks M1, M2 ₁ -M2 ₄ of CD bar 46 of measurement stage MST in the detection region of the alignment systems AL1, AL2 ₁ ~AL2 _4. Then, through a Z · leveling mechanism of the measuring stage MST, Figure 3 the upper surface of the CD bar 46 from the state of (A) a (mark formation surface), it until the alignment is a need in the process system AL1, AL2 ₁ ~ scanning in the Z direction in a range wider than the range of the best focus position of AL2 _4. Further, in synchronization with this scan, under the control of the main controller 20, the offset correction unit 132 changes the Z position of the CD bar 46 by a predetermined amount ΔZFM (a value about the measurement resolution of the AF systems 6A to 6E). Each time, the imaging signals SX and SY obtained from the imaging elements 5d of the alignment systems AL1, AL2 _{1 to} AL2 ₄ and the focus signal FS obtained via the AF systems 6A to 6E are captured.

Next, the offset correction unit 132 corresponds to the average position (best focus position) of the Z position of the CD bar 46 when the contrast of the imaging signals SX and SY becomes the highest for each of the alignment systems AL1, AL2 _{1 to} AL2 _4. The focus signal offset is set in the detection signal processing units 131A to 131E so that the focus signal FS measured by the AF systems 6A to 6E to be zero becomes zero. Thereafter, the defocus amount of the test surface with respect to the best focus position of the alignment systems AL1, AL2 _{1 to} AL2 ₄ is accurately obtained from the focus signal FS obtained via the AF systems 6A to 6E. Is supplied to the main controller 20.

In the next step 303, by using the measured values of the encoders 70A to 70F in FIG. 7 including the Y heads 64, 64y ₁ , 64y ₂ and the X head 66 in FIG. 4, that is, by driving the wafer stage WST on the basis of the encoders. The origins of the image sensors of the alignment systems AL1, AL2 _{1 to} AL2 ₄ are set. It should be noted that wafer stage WST is driven based on an encoder during subsequent alignment and exposure. That is, first, as shown in FIG. 11A, the center of the reference mark FM is aligned with the detection center of the primary alignment system AL1 (conjugate point of the center of the image sensor). At this stage, no wafer W is loaded on wafer stage WST. Thereafter, the wafer stage WST by a secondary baseline SBL2 + X direction by driving, to detect the reference mark FM by secondary alignment systems AL2 _2, the imaging plane pixel of the image pickup element in the center of the reference mark FM of the image at that time The origin of Similarly, the wafer stage WST is moved in the + X direction or the −X direction by the secondary baselines SBL1, SBL3, and SBL4 in FIG. 10, and the reference marks FM are detected by the secondary alignment systems AL2 ₁ , AL2 ₃ , and AL2 ₄ , respectively. The pixel of the image sensor at the center of the image of the reference mark FM at that time is set as the origin of the imaging surface. The origin may be the center of the mark image obtained by interpolating the imaging signal. Thereafter, assuming that there is no change over time, on the test surface (the upper surface of the wafer, etc.) corresponding to the origin of the imaging surface of the primary alignment system AL1 and the origin of the imaging surfaces of the secondary alignment systems AL2 _{1 to} AL2 ₄ The interval between the points (detection centers) in the X direction is precisely the initial value of the secondary baselines SBL1 to SBL4.

However, in actuality, since a slight change with time may occur, before the exposure of each wafer in steps 306 to 308, the secondary baseline is determined based on the known phase (interval information) of the reference mark on the CD bar 46. The amount of change in SBL1 to SBL4 is measured. That is, after wafer stage WST is directed to the loading position, in step 306, measurement stage MST is driven to align reference marks M1, M2 _{1 to} M2 ₄ on CD bar 46 as shown in FIG. Move to the detection area of the systems AL1, AL2 _{1 to} AL2 ₄ . Then, the reference mark M2 ₁ is detected by the secondary alignment system AL2 ₁ , and at the same time, using the focus signals from the AF systems 6A and 6B, the alignment system AL1 and AL2 ₁ are set so that the test surface comes to the best focus position, respectively. While leveling the bar 46, the primary alignment system AL1 also detects the reference mark M1. Two reference marks M1, M2 ₁ detection result (position shift amount from the detection center) are supplied to the alignment calculation system 20a in FIG.

In the next step 307, as shown in FIG. 12 (B), using the focus signals from the AF systems 6A and 6C, the CD bar is set so that the test surface comes to the best focus position in the alignment systems AL1 and AL2 _2. At the same time, the reference marks M1 and M2 ₂ are detected by the alignment systems AL1 and AL2 ₂ while performing the leveling of 46, and the detection results (position shift amounts from the detection center) of the two reference marks M1 and M2 ₂ are shown in FIG. Supplied to the alignment calculation system 20a. Similarly, with respect to the other secondary alignment systems AL2 ₃ and AL2 ₄ , in a state where the CD bar 46 is leveled and focused, the corresponding reference marks are detected simultaneously with the primary alignment system AL1, and the detection results are subjected to alignment calculation. Supply to system 20a.

In the next step 308, the alignment calculation system 20a provides information on the known distance between the two reference marks M1 and M2 ₁ (or M2 _{2 to} M2 ₄ ) and the measured positional deviation amount of the two reference marks. Using the information, values after time-dependent changes of the secondary baselines SBL1 to SBL4 in FIG. 10 are obtained and stored. In this case, the position of the measurement stage MST (CD bar 46) slightly varies due to disturbance or the like. However, as in this embodiment, the primary alignment system AL1 (an alignment system in which the detection region is fixed) is simultaneously provided with one secondary alignment system (any one of AL2 _{1 to} AL2 ₄ ) in which the detection region is variable while always performing leveling. However, by detecting the reference mark, the secondary baseline can be measured with high accuracy at the best focus position without being affected by the position fluctuation of the CD bar 46.

For example, in the example of FIG. 12B, the positions of the reference marks M2 ₁ and M2 ₂ may be detected simultaneously while leveling with the _two secondary alignment systems AL2 ₁ and AL2 ₂ . In this case, by subtracting the distance between the reference marks M2 ₁ and M2 ₂ from the distance between the reference marks M1 and M2 ₁ in FIG. The secondary baseline SBL2 in FIG. 10 can be measured with high accuracy. Accordingly, the common alignment system may not be the primary alignment system AL1 when the reference marks are detected simultaneously by the two alignment systems (any _{one of} AL1, AL2 _{1 to} AL2 ₄ ) while sequentially performing leveling.

Further, for example, in FIG. 12A, when it is known that the best focus positions of the three alignment systems AL1, AL2 ₁ , AL2 ₂ are on a straight line, the upper surface of the CD bar 46 is brought to the straight line by leveling. The positions of the corresponding reference marks may be detected simultaneously by the three alignment systems AL1, AL2 ₁ and AL2 ₂ . In this case, the two secondary baselines SBL1 and SBL2 can be measured with high accuracy at the best focus position by one measurement.

  Next, in step 309 in FIG. 17, at the loading position LP in FIG. 13A, the first wafer (referred to as wafer W) of one lot is loaded onto wafer stage WST. The shot arrangement of the wafer W is as shown in FIG. Thereafter, main controller 20 moves wafer stage WST obliquely upward to the left in FIG. 13A to a predetermined position (alignment start position) where the center of wafer W is located on straight line LV. Position it. In the state positioned at the alignment start position, a straight line that passes through the center of the wafer W and passes through the center of the wafer mark attached to the shot region arranged parallel to the Y axis passes through the detection center of the primary alignment system AL1. During the following alignment, wafer stage WST moves substantially along the Y axis. For this reason, alignment can be performed efficiently.

In the next step 310, as one process for measuring the baseline BL, which is the distance in the Y direction between the detection center of the primary alignment system AL1 and the center of the image by the projection optical system PL of the reticle R in FIG. Wafer stage WST is driven in the Y direction, and reference mark FM on measurement plate 30 on wafer stage WST is detected by primary alignment system AL1 as shown in FIG. 11A. This detection result (position shift amount from the detection center) and the coordinates measured by encoders 70A to 70F of wafer stage WST at this time are supplied to alignment arithmetic system 20a.
Note that the origin setting operation in step 303 may be executed before and after the operation in step 310 for the first wafer in one lot.

Next, at step 311 in FIG. 18, main controller 20 determines whether or not wafer W on wafer stage WST is the first wafer of one lot. If it is the first wafer, the main controller 20 proceeds to step 315 and is not the first wafer. If so, the process proceeds to step 320. At this stage, since the wafer W is the leading wafer, the operation proceeds to step 315. Then, in order to calibrate the AF systems 6A to 6E for the alignment systems AL1, AL2 _{1 to} AL2 ₄ corresponding to the actual wafer marks, the main controller 20 drives the wafer stage WST in the Y direction. As shown in FIG. 14 (A), as an example, the wafer marks WMA, WMB, WMC, WMD, WME of five alignment shots arranged in the X direction on the wafer W are transferred to five alignment systems AL1, AL2 _{2 to} AL2 ₄ . Move to the detection area. At this time, since the wafer marks WMA to WME are concave and convex marks and may be asymmetric in the measurement direction (here, the X direction), they are measured by the AF systems 6A to 6E using the offset set in step 302. There is a possibility that a new offset may be generated between the best focus position and the best focus position determined by the above-described evaluation criteria A to C from the imaging signals of the alignment systems AL1, AL2 _{1 to} AL2 ₄ .

Therefore, in the next step 316, as shown in FIG. 14B, the focus signals of the AF systems 6C and 6D (offset is set in step 302) via the Z / leveling mechanism of wafer stage WST. On the basis of this, in a state where the surface of the wafer W is inclined in parallel to a straight line connecting the best focus positions of the inner secondary alignment systems AL2 ₂ and AL2 ₃ , a predetermined range including the straight line (Z of the CD bar 46 in step 302). The wafer W is scanned in the Z direction within a range narrower than the scanning width in the direction). Further, in synchronization with this scan, the offset correction unit 132 in FIG. 3A performs the imaging signal and AF obtained from the alignment systems AL2 ₂ and AL2 ₃ every time the Z position of the wafer W changes by the ΔZFM. A focus signal obtained via the systems 6C and 6D is taken in.

In the next step 317, the offset correction unit 132 corresponds to the Z position (wafer mark) of the wafer W when the contrast (or rate of change in the measurement direction, etc.) of the imaging signals of the alignment systems AL2 ₂ and AL2 ₃ is the highest. A new offset is set in the detection signal processing units 131C and 131D in FIG. 14C so that the focus signal measured using the corresponding AF systems 6C and 6D becomes 0 at the best focus position. Thereafter, from the focus signals obtained via the AF systems 6C and 6D, the surface of the wafer W is dereferenced based on the best focus position (corrected best focus position) with respect to the wafer marks of the alignment systems AL2 ₂ and AL2 _3. The focus amount is accurately obtained, and information on the defocus amount is supplied to the main controller 20. Therefore, by performing the leveling of the wafer W on the basis of the defocus amount, in a state in which the upper surface was focused to the two alignment systems AL2 _2, AL2 ₃ wafer W to the best focus position after correction, alignment systems AL2 ₂ , AL2 ₃ detect the corresponding wafer marks WMC, WMD, and supply the detection results (the amount of mark displacement and the coordinate values measured by the encoders 70A to 70F of the wafer stage WST) to the alignment calculation system 20a.

In the next step 318, when the two-lens alignment system remains in the alignment systems AL1, AL2 _{1 to} AL2 ₄ in FIG. 14A, the process returns to step 316, for example, alignment of the outer two eyes. The operations of steps 316 and 317 are repeated for the systems AL2 ₁ and AL2 ₄ . That is, a new offset for the focus signals of the AF systems 6B and 6E is obtained in accordance with the best focus position of the alignment systems AL2 ₁ and AL2 ₄ with respect to the wafer mark. Thereafter, by performing the leveling of the wafer W by focusing the upper surface of the wafer W to the best focus position of the corrected alignment systems AL2 _1, AL2 _4, alignment systems AL2 _1, the corresponding wafer mark WMB by AL2 _4, the WME The detection result is supplied to the alignment calculation system 20a.

  Next, the operation shifts from step 318 to step 319, and the operations of steps 316 and 317 are repeated for the remaining primary alignment system AL1 (however, the surface of the wafer W is parallel to the XY plane). ) That is, after obtaining the offset of the AF system 6A in accordance with the best focus position of the alignment system AL1 with respect to the wafer mark, the alignment mark ALMA is detected in the in-focus state by the alignment system AL1, and the detection result is used as the alignment calculation system 20a. To supply.

If the number of alignment systems AL1, AL2 _{1 to} AL2 ₄ is an even number, step 319 can be omitted. In this way, by obtaining the best focus position with respect to the wafer mark for each two-lens alignment system, the upper surface of the wafer W is focused on the best focus position of the two-lens alignment system after correction, and the wafer mark The position can be detected. Therefore, the best focus position of the alignment systems AL1, AL2 _{1 to} AL2 ₄ with respect to the wafer mark can be obtained almost in synchronization with the normal operation of detecting the wafer mark, and the throughput of the exposure process is hardly lowered.

Instead of the operations in steps 316 to 319, as in step 302, as shown in FIG. 14A, the wafer marks WMA to WME are detected by all the alignment systems AL1, AL2 _{1 to} AL2 _4. Alternatively, the wafer W may be scanned in the Z direction to obtain the best focus position with respect to the wafer mark. In this case, the best focus position of the five-lens alignment system with respect to the wafer mark can be obtained efficiently. However, after that, it is necessary to separately perform an operation of detecting the wafer mark using the two-lens alignment system and the last single-lens alignment system.

Further, for example, it is known that the difference between the best focus position with respect to the reference mark and the best focus position with respect to the wafer mark of the alignment systems AL1, AL2 _{1 to} AL2 ₄ is small, for example, because the symmetry of the wafer mark is good. In such a case, the operations of step 311 to step 319 may be omitted. In this case, the wafer mark detection operation from step 320 is immediately performed on the first wafer.

Next, at step 320, main controller 20 moves wafer stage WST by a predetermined distance in the Y direction based on the measurement values of encoders 70A to 70F, and positions it at the position shown in FIG. Using the alignment system AL1 and the secondary alignment systems AL2 ₂ and AL2 ₃ , the wafer marks attached to the three first alignment shots AS are detected almost simultaneously and individually (see the star mark in FIG. 13A). At this time, as in the case of FIG. 14B, for example, first, in the secondary alignment systems AL2 ₂ and AL2 ₃ for two eyes, the defocus amount measured by the AF systems 6C and 6D is zero so that the wafer W Wafer marks are detected while leveling. In the next step 321, the remaining primary alignment system AL1 is used to detect the wafer mark in a state where the upper surface of the wafer W is focused on the best focus position of the primary alignment system AL1 using the focus signal of the AF system 6A. To do. The detection results of the _three alignment systems AL1, AL2 ₂ and AL2 ₃ and the measured values of the encoders 70A to 70E at the time of detection are associated with each other and supplied to the alignment calculation system 20a. At this time, the secondary alignment systems AL2 ₁ and AL2 _{4 at} both ends that have not detected the wafer mark may or may not irradiate the wafer table WTB (or the wafer) with the detection light. good.

Next, in step 322, main controller 20 determines whether or not there is a wafer mark to be measured. At this stage, main controller 20 moves wafer stage WST by a predetermined distance in the + Y direction based on the measurement values of encoders 70A to 70E, and five alignment systems AL1, AL2 _{1 to} AL2 ₄ are moved to FIG. The wafer marks WMF, WMG, WMH, WMI, and WMJ attached to the five second alignment shots AS on the wafer W shown in A) are positioned at positions that can be detected almost simultaneously and individually.

First, using the outer two-lens secondary alignment systems AL2 ₁ and AL2 ₄ , the wafer stage WST is moved so that the defocus amount measured by the AF systems 6B and 6E (see FIG. 14A) becomes zero. While driving and leveling the wafer W, the wafer marks WMG and WMJ are simultaneously detected by the secondary alignment systems AL2 ₁ and AL2 ₄ .
Subsequently, as shown in FIG. 15B, using the inner two-lens secondary alignment systems AL2 ₂ and AL2 ₃ , the wafer stage is set so that the defocus amount measured by the AF systems 6C and 6D becomes zero. While leveling the wafer W by driving the WST, the wafer marks WMH and WMI are simultaneously detected by the secondary alignment systems AL2 ₂ and AL2 ₃ . In the next step 321, as shown in FIG. 15C, the wafer stage WST is driven by using the primary alignment system AL 1 so that the defocus amount measured by the AF system 6 A becomes zero. While controlling the Z position, the wafer mark WMF is detected by the primary alignment system AL1. The detection results of these wafer marks WMF to WMJ and the measurement values of the encoders 70A to 70F at the time of detection are also supplied to the alignment calculation system 20a.

When detecting the wafer mark shown in FIGS. 15A to 15C, an operation for obtaining the offset of the AF systems 6A to 6E of the alignment system is executed in accordance with the actual wafer mark shown in steps 315 to 319. Also good. Instead, at the time of detecting the wafer mark in the three first alignment shot areas AS shown in FIG. 13C, an operation for obtaining the offset of the corresponding AF system 6A, 6C, 6D is executed, and the following FIG. When the wafer marks are detected by the secondary alignment systems AL2 ₁ and AL2 ₄ on both sides, an operation for obtaining the offsets of the corresponding AF systems 6B and 6E may be executed.

Next, the operation returns from step 322 to step 320 again, and main controller 20 moves wafer stage WST by a predetermined distance in the + Y direction, and as shown in FIG. 13B, five alignment systems AL1, AL2 _{1 to} AL2 ₄ position the wafer marks attached to the five third alignment shots AS on the wafer W at positions where they can be detected almost simultaneously and individually. Then, Steps 320 and 321 are executed, and the detection results of the five wafer marks by the alignment systems AL1, AL2 _{1 to} AL2 ₄ are associated with the measurement values of the encoders 70A to 70F at the time of detection, and supplied to the alignment calculation system 20a. To do.

Next, the operation returns from step 322 to step 320, and main controller 20 moves wafer stage WST by a predetermined distance in the + Y direction and uses primary alignment system AL1, secondary alignment systems AL2 ₂ , AL2 ₃ and wafer W. The wafer marks attached to the above three force alignment shots AS are positioned at positions where they can be detected almost simultaneously and individually. Then, Steps 320 and 321 are executed to associate the detection results of the three wafer marks by the three alignment systems AL1, AL2 ₂ and AL2 ₃ with the measurement values of the encoders 70A to 70E at the time of the detection, and the alignment calculation system 20a. To supply. Since measurement of the wafer mark is completed at this stage, the operation shifts from step 322 to step 323, and main controller 20 drives wafer stage WST in the Y direction, as shown in FIG. Wafer stage WST and measurement stage MST are connected.

  Next, the slit pattern SL (see FIG. 5A) of the measurement plate 30 of the wafer stage WST is moved below the projection optical system PL, and the reticle stage RST of FIG. 1 is driven to light the center of the reticle R. Irradiation light IL is irradiated in accordance with the axis AX. Then, the image of the alignment mark on the reticle R is scanned with the slit pattern SL, the position is detected using the aerial image measurement device in the measurement stage MST, and the position information of the image (measured values of the encoders 70A to 70F). ) Is supplied to the alignment calculation system 20a. The alignment calculation system 20a can obtain the baseline BL shown in FIG. 11A from the detection result of step 310 and the detection result of step 323.

The operation of step 323 can be executed when the tip of the projection optical system PL approaches the measurement plate 30 during the measurement of the wafer marks of the four alignment shots in FIG. . This reduces the amount of movement of wafer stage WST and improves the exposure process throughput.
In the next step 324, the alignment calculation system 20a performs the encoder 70A corresponding to the detection results of the secondary baselines SBL1 to SBL4 obtained in step 308, the baseline BL obtained in step 323, and the total of 16 wafer marks. Statistical calculation is performed by using the EGA method disclosed in, for example, Japanese Patent Application Laid-Open No. 61-44429 (corresponding US Pat. No. 4,780,617) and the like using the measured values of ˜70E. Then, the arrangement of all shot regions on the wafer W on the stage coordinate system (for example, the XY coordinate system having the optical axis of the projection optical system PL as the origin) defined by the measurement axes of the encoders 70A to 70E is calculated. To do.

  Next, in step 325, as shown in FIGS. 13A and 13B, wafer stage WST is driven in the + Y direction, and the oblique incidence type multi-point AF system (90a, 90b) is used. Then, the Z position distribution (unevenness distribution) on the surface of the wafer W is measured. Then, in step 326, under the control of main controller 20, as shown in FIG. 16, wafer stage WST is measured using the measurement values of encoders 70A to 70F based on the array coordinates supplied from alignment calculation system 20a. , The pattern image of the reticle R is exposed on the entire shot area on the wafer W by the liquid immersion method and the step-and-scan method. The exposed wafer W is unloaded from wafer stage WST.

  In the next step 327, it is determined whether or not there is an unexposed wafer in one lot. If there is an unexposed wafer, the operation proceeds to step 306 in FIG. Measurement of a secondary baseline using marks, loading of a new wafer, and the like are executed. Since this time is the second and subsequent wafers, the operation shifts from step 311 to step 320, the wafer mark on the wafer is detected, and then the wafer scanning exposure is performed. Then, when there are no unexposed wafers in step 327, the exposure process for one lot of wafers ends.

As described above, in this embodiment, the five-stage alignment systems AL1, AL2 _{1 to} AL2 ₄ are used by moving the wafer stage WST in the Y direction and positioning the wafer stage WST at four positions on the movement path. Thus, it is possible to detect wafer mark position information in a total of 16 alignment shots AS. At this time, since it is not necessary to move wafer stage WST in the X direction, the wafer stage is driven in the X direction and the Y direction using a single alignment system to sequentially detect the wafer marks. Position information of a large number of wafer marks can be obtained in a very short time. Therefore, alignment can be performed in a short time.

Note that the five-eye alignment systems AL1, AL2 _{1 to} AL2 ₄ of the above embodiment can be regarded as one alignment system (mark detection system) having at least five detection regions separated in the X direction.
The effect of this embodiment is as follows.
(1) The alignment method by the exposure apparatus 100 of the above embodiment is a plurality of alignment systems AL1, AL2 _{1 to} AL2 ₄ having different detection areas in at least the X direction (uniaxial direction), and positions different from each other at least in the X direction. Is a mark detection method for detecting a wafer mark on the wafer W placed in the main control unit 20 and the alignment calculation system 20a, and the following control is performed. That is, among the plurality of reference marks arranged on the CD bar 46 at specific positional relationships (known X-direction and Y-direction intervals) whose positions in the X direction are different from each other, the first set of reference marks M1, Step 306 for detecting M2 ₁ with a corresponding set of alignment systems AL1 and AL2 ₁ (FIG. 12A), among the plurality of reference marks, the first set of reference marks and one reference mark M1 And a second set of fiducial marks M1, M2 ₂ that are common to each other with a corresponding set of alignment systems AL1, AL2 ₂ (FIG. 12B), and the corresponding fiducials of the alignment system Step 308 for obtaining information (secondary baseline) of the positional relationship of the plurality of alignment systems based on the detection result of the mark and the specific positional relationship of the plurality of reference marks; A.

  According to the present embodiment, a plurality of alignment systems having different detection areas in at least the X direction (or alignment systems having a plurality of detection areas having at least different positions in the X direction) are used. Since a plurality of different marks can be detected by the alignment system (or two detection regions), a plurality of wafer marks on the wafer W can be detected efficiently.

Further, even if the position of the CD bar 46 varies by detecting a plurality (one set) of reference marks on the CD bar 46 with the corresponding plurality (one set) of alignment systems, the positional relationship of the plurality of alignment systems (Secondary baseline) can be measured with high accuracy, and the subsequent measurement accuracy is improved.
(2) In the alignment method of the above embodiment, at least a plurality of alignment systems AL1, AL2 _{1 to} AL2 ₄ having different detection regions in the X direction on the wafer W arranged at different positions at least in the X direction. Mark detection method for detecting a wafer mark of the following, and the following control is performed by main controller 20, offset correction unit 132, AF systems 6A to 6E (defocus information measurement system), and wafer stage WST (Z leveling mechanism). Is done. That is, in step 315 for detecting the marks by moving wafer marks WMA to WME at different positions on the wafer W to the detection regions of the plurality of alignment systems (FIG. 14A), the wafer W Step 316 of measuring each imaging signal (detection information) of the plurality of alignment systems and focus signal (defocus information) of the detection region while gradually changing at least one of the Z position (height) and the inclination angle of A step 317 for obtaining an offset (correction information) of the focus signal from information on the best focus position (in-focus state) obtained from each imaging signal of the plurality of alignment systems and a focus signal in the detection region. .

According to this, since a plurality of wafer marks on the wafer are detected in parallel by a plurality of alignment systems and the defocus information is corrected, the defocus information can be corrected efficiently, and the subsequent wafer marks can be corrected. The focusing accuracy is improved and the measurement accuracy is improved.
(3) In addition, an alignment method by the exposure apparatus 100 of FIG. 1, alignment systems AL1 position about at least the X direction (one axis direction) with different multiple detection regions AL1f~AL2 ₄ f together, AL2 ₁ AL24 ₄ In the mark detection method for detecting wafer marks on wafers (objects) arranged at positions different from each other at least in the X direction, a CD in which a plurality of reference marks are arranged in a specific positional relationship where the positions in the X direction are different from each other. The bar 46 is positioned in two of the plurality of detection regions in a posture inclined with respect to the X axis, and the two of the two detection regions are moved relative to each other without moving the CD bar 46 and the two detection regions in the X direction. and the reference marks M1, M2 ₁ in the detection area substantially simultaneously detected (FIG. 12 (a), the step 306). Further, based on the result of detecting the marks in the two detection areas and the information on the specific positional relation regarding the arrangement of the plurality of reference marks in the CD bar 46, the positional relation information (secondary baseline) of the two detection areas is obtained. ), And the wafer marks WMG and WMJ are detected substantially simultaneously in the two detection areas without relatively moving the two detection areas and the wafer mark on the wafer in the X direction (FIG. 15). (A), step 320), from the result of detecting the wafer mark in the two detection areas substantially simultaneously and the positional relationship information (secondary baseline) of the two detection areas, in each of the two detection areas. The position information of each detected wafer mark is obtained.

1 includes a plurality of detection regions AL1f and AL2 ₁ f to AL2 ₄ f having positions different from each other at least in the X direction, and on a wafer arranged at positions different from each other at least in the X direction. A mark detection apparatus including alignment systems AL1, AL2 _{1 to} AL2 ₄ that detect substantially the same wafer mark at the same time, and a CD bar 46 in which a plurality of reference marks are arranged in a specific positional relationship with respect to different positions in the X direction. And the relative movement of the CD bar 46 and the two detection areas in the X direction, with the CD bar 46 tilted with respect to the X axis and positioned in two of the plurality of detection areas. The result of detecting the reference marks in the two detection areas substantially simultaneously and the plurality of Comprises from its specific positional relationship information regarding the placement of the quasi-mark, the alignment calculation system 20a for determining the positional relationship information of the two detection regions (secondary baseline), the. The two detection areas and the wafer mark on the wafer are detected in the two detection areas substantially simultaneously without relatively moving in the X direction, and the wafer is detected in the two detection areas. The position information of each wafer mark detected in each of the two detection areas is obtained from the result of detecting the marks substantially simultaneously and the positional relationship information of the two detection areas.

According to the present embodiment, by detecting the two reference marks on the CD bar 46 in the two detection areas while leveling, the secondary baseline can be measured with high accuracy in the focused state. Accordingly, the position of the wafer mark can be detected with high accuracy thereafter using a plurality of alignment systems.
(4) In the alignment method of the above embodiment, alignment systems AL1, AL2 _{1 to} AL2 ₄ having a plurality of detection regions having positions different from each other at least in the X direction are arranged at positions different from each other at least in the X direction. A mark detection method for detecting a wafer mark on a wafer, wherein the wafer is positioned in two of the plurality of detection areas (mark detection is performed in the two detection areas), and the Z of the wafer is detected. A first set of wafer marks WMC, WMD on the two detection areas are detected while gradually changing at least one of the position in the direction (height direction) and the inclination of the wafer (FIG. 14 ( B), Steps 315 and 316), each of the results detected in the two detection areas is evaluated according to a predetermined evaluation standard, and the wafer The second set of wafer marks WMH, WMI different from the first set of wafer marks on the wafer is detected in the two detection areas based on the evaluation result (see FIG. 15 (B), step 320).

  According to this mark detection method, two wafer marks on the wafer are detected in the corresponding two detection areas, and after correcting the defocus information, the wafer mark can be detected in the focused state as it is. Accordingly, a decrease in throughput based on the operation for correcting the defocus information is suppressed, and the focusing accuracy at the subsequent detection of the wafer mark is improved, thereby improving the measurement accuracy.

(5) In the alignment method of the above embodiment, the mark detection systems AL1, AL2 _{1 to} AL2 ₄ having a plurality of detection regions having positions different from each other at least in the X direction are arranged at positions different from each other at least in the X direction. A mark detection method for detecting a wafer mark on a wafer, wherein a CD bar positioned in each of the plurality of detection areas is gradually changed in a Z-direction position of a CD bar 46 on which a reference mark is formed. detecting the reference marks M1, M2 ₁ on 46 (FIG. 3 (a), the step 302), the respective results detected by the plurality of detection areas evaluated by predetermined criteria, the wafer, the results of the evaluation And the wafer mark is placed in two of the plurality of detection areas (FIG. 15B, step 320). WMH and WMI are detected substantially simultaneously.

According to this mark detection method, the focus accuracy of the alignment system can be improved by determining the best focus position of the alignment system using the reference mark, and two wafer marks on the wafer are detected in two detection areas. As a result, the wafer mark can be measured efficiently at the same time in a focused state with high accuracy.
(6) In the above-described embodiment, the wafer stage WST that holds the wafer W and is movable in the X direction and the Y direction intersecting with the wafer W is provided on one surface of the wafer stage WST. Encoders 70B and 70D having scales 39X ₁ , 39X ₂ and 39Y ₁ , 39Y ₂ (first and second grating portions) in which gratings are periodically arranged in the direction, and a plurality of X heads 66 having different positions in the Y direction And a measuring device having encoders 70A and 70C having a plurality of Y heads 64 having different positions in the X direction, and position information in the X direction of wafer stage WST by X head 66 facing scales 39X ₁ and 39X _2. was measured, not measure the position information in the Y direction of the wafer stage WST by the scale 39Y _1, 39Y ₂ and facing Y heads 64 .

Therefore, since the optical path length of the detection light of encoders 70A to 70D is short, the position of wafer stage WST can be measured with high accuracy with almost no influence of fluctuations compared to the case of using a laser interferometer.
As the encoders 70A to 70D and 70E, 70F, a magnetic linear encoder or the like including a periodic magnetic scale in which a magnetic body whose polarity is reversed is formed at a minute pitch and a magnetic head that reads the magnetic scale is used. It is also possible to do. When the influence of the fluctuation of the optical path is small, the position of wafer stage WST may be measured using only the laser interferometer.

(7) The exposure apparatus of the above embodiment is an exposure apparatus that exposes the wafer W (object) with the illumination light IL (energy beam), and is a wafer stage WST (moving body) that holds and moves the wafer W. ) And a mark detection device including the plurality of alignment systems AL1, AL2 _{1 to} AL2 ₄ of the above-described embodiment, and using the mark detection device, a predetermined plurality of wafer marks on the wafer W are detected, Based on the detection result of the wafer mark, the illumination light is driven while driving the wafer W via the wafer stage WST in order to align the irradiation position of the illumination light IL (pattern image of the reticle R) with the wafer W. The wafer W is exposed with IL.

In addition, the exposure apparatus of the above embodiment includes a position control device including the plurality of alignment systems AL1, AL2 _{1 to} AL2 ₄ of the above embodiment, and the position is controlled on the wafer using the position control device. It is also an exposure apparatus that exposes a device pattern.
Further, the alignment method or apparatus of the above embodiment uses the position information of the wafer mark on the wafer W obtained by using the mark detection method using the plurality of alignment systems AL1, AL2 _{1 to} AL2 ₄ of the above embodiment. It is also an object position control method or apparatus for controlling the position of the wafer W.

In these cases, by using the alignment systems AL1, AL2 _{1 to} AL2 _{4 in} which offset adjustment of a plurality of best focus positions is performed, a plurality of marks can be measured efficiently and with high accuracy, so that position control and exposure are efficient. And with high accuracy.
When a microdevice such as a semiconductor device is manufactured using the exposure apparatus according to the above-described embodiment, the microdevice is designed in step 221 for performing function / performance design of the microdevice, as shown in FIG. Step 222 for producing a mask (reticle) based on the above, Step 223 for producing a substrate (wafer) as a base material of the device, and exposing the pattern of the reticle onto the substrate by the exposure apparatus 100 (projection exposure apparatus) of the above-described embodiment. A substrate processing step 224 including a process, a process of developing the exposed substrate, a heating (curing) and etching process of the developed substrate, a device assembly step (including processing processes such as a dicing process, a bonding process, and a packaging process) 225, In addition, it is manufactured through an inspection step 226 and the like.

In other words, the device manufacturing method includes exposing the substrate (object) using the exposure apparatus of the above-described embodiment and developing the exposed substrate. Further, this device manufacturing method includes exposing a device pattern on a substrate (object) whose position is controlled using the alignment method (position control method) of the above-described embodiment.
At this time, since the substrate can be efficiently aligned (detection of alignment marks) using a plurality of alignment systems, the device can be mass-produced with high throughput.

The present invention can also be applied to a step-and-repeat type projection exposure apparatus (stepper or the like) in addition to the above-described step-and-scan type scanning exposure type projection exposure apparatus (scanner). Further, the present invention can be similarly applied to a dry exposure type exposure apparatus other than the immersion type exposure apparatus.
Further, the present invention is not limited to an exposure apparatus for manufacturing a semiconductor device, but is used for manufacturing a display including a liquid crystal display element, a plasma display, and the like. An exposure apparatus for transferring a device pattern onto a glass plate and a thin film magnetic head. Applicable to exposure equipment that transfers device patterns used in ceramics onto ceramic wafers, as well as exposure equipment used to manufacture imaging devices (CCD, etc.), organic EL, micromachines, MEMS (Microelectromechanical Systems), and DNA chips. can do. Further, the present invention is applied not only to a micro device such as a semiconductor element but also to an exposure apparatus that transfers a circuit pattern to a glass substrate or a silicon wafer in order to manufacture a mask used in an optical exposure apparatus and an EUV exposure apparatus. Applicable. Thus, the present invention is not limited to the above-described embodiments, and various configurations can be taken without departing from the gist of the present invention.

It is a figure which shows schematic structure of the exposure apparatus which concerns on an example of embodiment of this invention. It is a top view which shows the stage apparatus of FIG. 3A is a diagram showing a schematic configuration of an alignment system for five eyes and an AF system for the alignment system as an example of the embodiment, FIG. 3B is a diagram showing an example of a focus signal of the AF system, and FIG. C) is a diagram showing an example of an imaging signal of the alignment system. It is a figure which shows arrangement | positioning of alignment system AL1, AL2 ₁ -AL2 _{4 of} FIG. 1, and the encoder for position measurement. FIG. 5A is a plan view showing the wafer stage, and FIG. 5B is a side view showing a part of the wafer stage WST. FIG. 6A is a plan view showing the measurement stage, and FIG. 6B is a side view with a part of the cross section showing the measurement stage. FIG. 2 is a block diagram showing a main configuration of a control system of the exposure apparatus in FIG. 1. 8A and 8B are diagrams for explaining the position measurement in the XY plane of the wafer table and the takeover of the measurement value between the heads by a plurality of encoders each including a plurality of heads arranged in an array. FIG. It is a figure which shows an example of arrangement | positioning of alignment system AL1, AL2 ₁ -AL2 ₄ . It is a figure which shows the state which driven secondary alignment system AL2 ₁ -AL2 ₄ . FIG. 11A is a diagram showing a state in which the reference mark FM is measured by the primary alignment system AL1, and FIG. 11B is a diagram showing a state in which an image of the reticle pattern is scanned with a slit pattern. Figure 12 (A) is a diagram showing a state of detecting the reference mark on the CD bar 46 in alignment systems AL1, AL2 ₁ of 2 eyes, and FIG. 12 (B) is CD bar 46 in two eyes of alignment systems AL1, AL2 ₂ It is a figure which shows the state which detects the upper reference mark. FIG. 13A shows a state in which the first alignment shot AS is measured, FIG. 13B shows a state in which the third alignment shot AS is measured, and FIG. 13C shows a wafer alignment shot AS. It is a figure which shows an example of the arrangement | sequence of. 14A shows a state in which the wafer mark on the wafer W has been moved to the detection areas of the alignment systems AL1, AL2 _{1 to} AL2 ₄ , and FIG. 14B shows a two-lens alignment system AL2 ₂ , AL2 ₃ . 6 is a diagram illustrating a state in which a wafer mark on a wafer W is detected. FIG. FIG. 15A shows a state in which wafer marks are detected by the two-lens alignment systems AL2 ₁ and AL2 ₄ , and FIG. 15B shows a state in which wafer marks are detected by the two-lens alignment systems AL2 ₂ and AL2 _3. FIG. 15C is a diagram showing a state in which a wafer mark is detected by the alignment system AL1. It is a top view which shows the state which scans a wafer while driving the wafer stage WST and moving a wafer. It is a flowchart which shows a part of example of the exposure operation | movement of embodiment. It is a flowchart which shows the exposure operation | movement following FIG. It is a flowchart which shows an example of the manufacturing process of a microdevice.

Explanation of symbols

AL1 ... primary alignment system, AL2 _{1 to} AL2 ₄ ... secondary alignment system, R ... reticle, W ... wafer, WTB ... wafer table, WST ... wafer stage, MTB ... measurement table, MST ... measurement stage, 20 ... main controller, 32 ... nozzle unit, 39X _1, 39X ₂ ... X scales, 39Y _1, 39Y ₂ ... Y scale, 46 ... CD bar, 62A to 62D ... head unit, 64 ... Y head, 66 ... X heads, 70A, 70C ... Y Encoder, 70B, 70D ... X encoder

Claims (26)

A mark detection method for detecting marks on an object arranged at positions different from each other in at least the one axis direction by using a plurality of mark detection systems having different detection areas in at least one axis direction,
Detecting a first set of marks with a corresponding set of mark detection systems among a plurality of marks arranged on a reference member in a specific positional relationship where the positions in the one axis direction are different from each other;
Detecting a second set of marks in common with the first set of marks and the first set of marks among the plurality of marks with a corresponding set of the mark detection systems;
Obtaining a positional relationship information of the plurality of mark detection systems based on a detection result of the corresponding mark of the mark detection system and the specific positional relationship of the plurality of marks.   The mark detection method according to claim 1, wherein each of the first and second sets of marks is two marks.   3. When detecting the first and second sets of marks, the reference member is tilted with respect to the one axis, and the two marks are focused on two corresponding mark detection systems. The described mark detection method. While measuring the position information of the moving body on which the predetermined mark is formed, moving the moving body along the one-axis direction, sequentially moving the predetermined mark to the detection areas of the plurality of mark detection systems, Detecting the predetermined marks sequentially with the plurality of mark detection systems;
2. Obtaining positional relationship information of the plurality of mark detection systems based on position information of the moving body measured when the predetermined marks are respectively detected by the plurality of mark detection systems. The mark detection method according to any one of items 1 to 3. In at least one of the plurality of mark detection systems, the detection region is movable with respect to the one-axis direction,
The mark detection according to claim 4, wherein the step of sequentially detecting the predetermined marks by the plurality of mark detection systems is performed after moving at least one of the detection areas of the plurality of mark detection systems with respect to the one axis direction. Method.   2. The method includes detecting a third set of marks that share a common mark with the first set of marks and the second set of marks using the corresponding set of mark detection systems. 6. The mark detection method according to any one of items 1 to 5.   The mark detection method according to claim 6, wherein a detection area of the mark detection system for detecting the common mark is fixed. Placing the object on a movable body movable in a first direction parallel to the one axis direction and a second direction intersecting the first direction;
On one surface of the moving body, first and second grating portions in which gratings are periodically arranged in the first and second directions are provided,
Using a measuring device having a first encoder having a plurality of first heads having different positions with respect to the second direction and a second encoder having a plurality of second heads having different positions with respect to the first direction;
When moving the moving body, position information of the moving body in the first direction is measured by the first head facing the first grating portion, and the moving is performed by the second head facing the second grating portion. The mark detection method according to claim 1, wherein position information of the body in the second direction is measured. In order to detect a plurality of marks arranged at different positions with respect to at least the one axis direction on the object using the plurality of mark detection systems,
Detecting a first set of marks among a plurality of marks on the object with a corresponding set of the mark detection systems;
Detecting a first set of marks and a second set of marks in common with the first set of marks on the object with a corresponding set of mark detection systems. The mark detection method according to any one of claims 1 to 8.   The mark detection method according to claim 9, wherein each of the first and second sets of marks on the object is two marks.   When detecting the first and second sets of marks on the object, the object is tilted with respect to the one axis, and the two marks are focused on two corresponding mark detection systems. Item 11. The mark detection method according to Item 10. An exposure method for exposing an object with an energy beam,
Detecting a plurality of predetermined marks on the object using the mark detection method according to any one of claims 9 to 11;
Based on the detection results of the predetermined marks on the object, the object is exposed with the energy beam while driving the object to align the irradiation position of the energy beam with the object. And an exposure method comprising: Exposing an object using the exposure method of claim 12;
Developing the exposed object. A mark detection device that detects marks on an object arranged at positions different from each other at least with respect to the one-axis direction by using a plurality of mark detection systems having different detection areas with respect to at least one axis direction,
A reference member in which a plurality of marks are arranged in a specific positional relationship in which the positions in the one axial direction are different from each other;
Among a plurality of marks arranged on the reference member, a first set of marks is detected using a corresponding set of the mark detection systems, and the first set of marks among the plurality of marks is detected. A second set of marks having a common mark and one mark are detected using a corresponding set of the mark detection systems, and the detection results of the corresponding marks of the mark detection system and the plurality of marks And a control device that acquires information on a positional relationship between the plurality of mark detection systems based on the specific positional relationship.   The mark detection apparatus according to claim 14, wherein each of the first and second sets of marks is two marks.   In detecting the first and second sets of marks, the reference member is tilted with respect to the one axis to focus the two marks on the corresponding two mark detection systems. The mark detection apparatus according to claim 15, further comprising an inclination mechanism for inclining the reference member. A moving body on which a predetermined mark is formed;
A measuring device for measuring positional information of the moving body;
The controller is
While moving the moving body along the one axis direction, the predetermined marks are sequentially moved to the detection areas of the plurality of mark detection systems, and the predetermined marks are sequentially detected using the plurality of mark detection systems. ,
The positional relationship information of the plurality of mark detection systems is obtained based on the position information of the moving body measured by the measuring device when the predetermined marks are respectively detected by the plurality of mark detection systems. The mark detection apparatus according to any one of 16.   The mark detection device according to claim 17, wherein at least one of the plurality of mark detection systems has the detection region movable with respect to the one-axis direction. In order to obtain the positional relationship information of the plurality of mark detection systems, the control device,
15. From the plurality of marks, the first set of marks and the third set of marks that share one mark with the first set of marks are detected using the corresponding set of mark detection systems. The mark detection device according to any one of claims 18 to 18.   The mark detection apparatus according to claim 19, wherein a detection area of the mark detection system for detecting the common mark is fixed. A movable body that holds the object and is movable in a first direction parallel to the one-axis direction and a second direction intersecting the first direction;
A first and second grating portion provided on one surface of the movable body and having a grating periodically arranged in the first and second directions; and a plurality of first heads having different positions with respect to the second direction. A measuring device comprising: a first encoder; and a second encoder having a plurality of second heads having different positions with respect to the first direction.
When the movable body holding the object is moved, the position information of the movable body in the first direction is measured by the first head facing the first grating portion, and the second head facing the second grating portion. 21. The mark detection apparatus according to claim 14, wherein position information of the movable body in the second direction is measured by two heads. The controller is
In order to detect a plurality of marks arranged at different positions with respect to at least the one axis direction on the object using the plurality of mark detection systems,
Detecting a first set of marks among a plurality of marks on the object using a corresponding set of the mark detection systems;
15. A plurality of marks on the object are detected by using a corresponding set of the mark detection systems to detect a second set of marks in common with the first set of marks and one mark. The mark detection apparatus as described in any one of 21.   23. The mark detection apparatus according to claim 22, wherein each of the first and second sets of marks on the object is two marks. A tilt mechanism for tilting the object with respect to the one axis;
When the control device detects the first and second sets of marks on the object, the control device tilts the object with respect to the one axis via the tilt mechanism to correspond to the two marks. The mark detection apparatus according to claim 23, wherein the two mark detection systems are focused. An exposure apparatus that exposes an object with an energy beam,
A moving body that moves while holding the object;
A mark detection device according to any one of claims 14 to 24,
In order to detect a plurality of predetermined marks on the object using the mark detection device, and to align the irradiation position of the energy beam and the object via the moving body based on the detection result An exposure apparatus that exposes the object with the energy beam while driving the object. Exposing an object using the exposure apparatus of claim 25;
Developing the exposed object.

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