JP2017215556A - Mark detection device, exposure apparatus, method for producing device, and method for detecting mark - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an alignment detection time.SOLUTION: An alignment system 30 has a plurality of alignment sensors 32p, 32s arranged at prescribed intervals to an X axis direction and capable of detecting grate marks GM provided at a wafer W via an optical system, and includes a mark detection system capable of simultaneously detecting a plurality of the grate marks GM provided at the object using the alignment sensors 32p, 32s and a control system calculating the position of the wafer W when the grate marks GM as the objects of detection are located in the focal depth of each optical system of the alignment sensors 32p, 32s.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a mark detection apparatus, an exposure apparatus, a device manufacturing method, and a mark detection method, and more specifically, a mark detection apparatus and a mark detection method for detecting a mark provided on an object, and an exposure including the mark detection apparatus. The present invention relates to an apparatus and a device manufacturing method using the exposure apparatus.

  Conventionally, in lithography processes for manufacturing electronic devices (microdevices) such as semiconductor elements (integrated circuits, etc.) and liquid crystal display elements, step-and-scan projection exposure apparatuses (so-called scanning steppers (also called scanners)), etc. Is used.

  In this type of exposure apparatus, a plurality of patterns are superimposed on a wafer or glass plate (hereinafter collectively referred to as “wafer”), so that a pattern already formed on the wafer and a mask or An operation (so-called alignment) is performed to bring the pattern of the reticle (hereinafter, collectively referred to as “reticle”) into an optimum relative positional relationship.

US Pat. No. 8,054,472

  According to the first aspect, the apparatus includes a plurality of detection devices that are arranged at predetermined intervals in a first direction within a predetermined two-dimensional plane and that detect marks provided on the object via the optical system. A mark detection system that simultaneously detects a plurality of marks provided on the object using a detection device, information on the focal depth of the optical system of each of the plurality of detection devices, and a second direction orthogonal to the two-dimensional plane And a control system that controls a positional relationship between the optical system of each of the plurality of detection devices and the object based on at least information related to the position of the object.

  According to the second aspect, the mark detection apparatus according to the first aspect, the positioning apparatus that positions the object according to the position calculated by the control system of the mark detection apparatus, and the positioning apparatus are positioned. An exposure apparatus comprising: a pattern forming apparatus that forms a predetermined pattern by exposing the object with an energy beam.

  According to a third aspect, there is provided a device manufacturing method including exposing the object using the exposure apparatus according to the second aspect and developing the exposed object.

  According to the fourth aspect, a plurality of marks provided on an object are simultaneously detected using a mark detection system including a plurality of detection devices arranged at predetermined intervals in a first direction within a predetermined two-dimensional plane. Each of the plurality of detection devices based at least on the information on the depth of focus of the optical system of each of the plurality of detection devices and the information on the position of the object in the second direction orthogonal to the two-dimensional plane. There is provided a mark detection method including controlling a positional relationship between the optical system and the object.

  According to a fifth aspect, there is provided a device manufacturing method for forming a plurality of patterns on an object by using a measuring apparatus that irradiates a mark including a diffraction grating with measurement light. Measuring the position of one mark, measuring the asymmetry of the first mark, correcting the position measurement result of the first mark using a correction coefficient according to the measurement result, Based on the corrected position measurement result of the first mark, a pattern is formed on the existing pattern on the object, and a second mark is formed on the first mark, and the first mark is formed. And measuring the overlay accuracy between the patterns using the second mark, and correcting the correction coefficient when the overlay accuracy measurement result does not satisfy a predetermined condition. Has an optical member for generating reference light that interferes with diffracted light from the mark of the measurement light, and performs the position measurement and the asymmetric measurement based on interference between the diffracted light and the reference light. A device manufacturing method is provided.

  According to the sixth aspect, there is provided a device manufacturing system that forms a plurality of patterns on an object by using a measuring device that irradiates measurement light to a mark including a diffraction grating. A measurement system that measures the position of one mark and performs asymmetric measurement related to the asymmetry of the first mark, and corrects the position measurement result of the first mark using a correction coefficient according to the scatterometry measurement result. A pattern is formed on the existing pattern on the object, and a second mark is formed on the first mark, based on the control system that performs the correction and the position measurement result of the corrected first mark. A pattern forming system and an overlay measurement system that measures the overlay accuracy of the patterns using the first and second marks, and the control system has a predetermined condition for the overlay accuracy measurement result. The measurement coefficient is corrected when the measurement coefficient is not satisfied, and the measurement apparatus includes an optical member for generating reference light that interferes with diffracted light from the mark of the measurement light, and the diffracted light and the reference light There is provided a device manufacturing system that performs the position measurement and the asymmetric measurement based on interference.

It is a figure which shows schematically the structure of the exposure apparatus which concerns on 1st Embodiment. It is a top view which shows the stage apparatus with which the exposure apparatus of FIG. 1 is provided. 3A illustrates an example of a lattice mark including an X lattice and a Y lattice, FIG. 3B illustrates an example of a lattice mark including an α lattice and a β lattice (part 1), and FIG. It is an example (the 2) of the lattice mark containing a lattice and (beta) lattice. FIG. 4A is a diagram schematically illustrating the configuration of the alignment sensor, and FIG. 4B is a diagram illustrating illumination light and diffracted light on the pupil plane of the objective lens included in the alignment sensor of FIG. It is a figure which shows the relationship. FIG. 2 is a view showing an arrangement relationship between an arrangement shot area set on a wafer and a plurality of alignment sensors provided in the exposure apparatus of FIG. 1. It is a figure which shows an example of the waveform produced | generated based on the output of the detector with which an alignment sensor is provided. FIG. 2 is a block diagram showing a main configuration of a control system provided in the exposure apparatus of FIG. 1. FIGS. 8A and 8B are diagrams (part 1 and part 2) for explaining the calibration operation of the alignment system. FIG. 9A and FIG. 9B are diagrams (No. 3 and No. 4) for explaining the calibration operation of the alignment system. FIG. 10 is a diagram (No. 5) for explaining the calibration operation of the alignment system. FIG. 11A to FIG. 11D are views (No. 1 to No. 4) showing a relative positional relationship between the alignment system and the wafer during the alignment operation. It is a flowchart for demonstrating the multi-eye simultaneous measurement operation | movement using an alignment system. It is a graph produced | generated by step S14 of the flowchart shown by FIG. It is a figure which shows the state which the telecentric property of the optical system which an alignment sensor has fell. FIG. 15A is a diagram illustrating a configuration of the alignment sensor according to the second embodiment, and FIG. 15B is a measurement light on the pupil plane of the objective lens included in the alignment sensor of FIG. It is a figure which shows the relationship between diffracted light. FIG. 16A is a diagram illustrating a configuration of the alignment sensor according to the third embodiment, and FIG. 16B is a measurement light on the pupil plane of the objective lens included in the alignment sensor of FIG. It is a figure which shows the relationship between diffracted light. FIG. 17A is a diagram illustrating a configuration of the alignment sensor according to the fourth embodiment, and FIG. 17B is a measurement light on the pupil plane of the objective lens included in the alignment sensor of FIG. It is a figure which shows the relationship between diffracted light. 18A and 18B are diagrams (No. 1 and No. 2) showing diffracted light from the grating mark. It is a flowchart for demonstrating the correction method of the alignment result based on a scatter measurement value. It is a figure for demonstrating how to obtain | require the correction coefficient used by FIG.19 S512. FIGS. 21A and 21B are views (No. 1 and No. 2) for explaining the overlap measurement operation by the overlap measuring instrument. It is a figure which shows the modification of a stage apparatus.

<< First Embodiment >>
The first embodiment will be described below with reference to FIGS.

  FIG. 1 schematically shows a configuration of an exposure apparatus 10 according to the first embodiment. The exposure apparatus 10 is a step-and-scan type scanning exposure apparatus.

  The exposure apparatus 10 includes an illumination system 12, a reticle stage 14 that holds a reticle R that is illuminated by exposure illumination light (hereinafter referred to as “illumination light” or “exposure light”) IL from the illumination system 12, and a reticle R. A projection unit 16 including a projection optical system 16b that projects illumination light IL emitted from the wafer W onto the wafer W, a local liquid immersion device 18 (not shown in FIG. 1, refer to FIG. 7), a stage including a wafer stage 24 and a measurement stage 26. The apparatus 20 includes an alignment system 30 and a control system thereof. A wafer W is placed on the wafer stage 24.

  The illumination system 12 includes an illumination uniformizing optical system including a light source, an optical integrator, etc., a beam splitter, a relay lens, a variable ND filter, a reticle blind, etc. as disclosed in US Patent Application Publication No. 2003/0025890. (Both not shown). The illumination system 12 illuminates the slit-shaped illumination area on the reticle R defined by the reticle blind with illumination light (exposure light) IL with a substantially uniform illuminance. As the illumination light IL, ArF excimer laser light (wavelength 193 nm) is used.

  On reticle stage 14, reticle R on which a circuit pattern or the like is formed on its pattern surface (the lower surface in FIG. 1) is fixed by vacuum suction. The reticle stage 14 can be finely driven in the XY plane by a reticle drive system 52 (not shown in FIG. 1, see FIG. 7) including a linear motor and the like, and has a predetermined scanning direction (here, in FIG. 1 on the paper surface). It is possible to drive at a scanning speed specified in the Y-axis direction which is the left-right direction.

  The position of the reticle stage 14 in the stage moving surface (including rotation around the Z axis) is measured by a reticle measurement system 56 (not shown in FIG. 1, see FIG. 7) including an encoder system (or laser interferometer system). The The measurement value of the reticle measurement system 56 is supplied to a main controller 50 (not shown in FIG. 1, refer to FIG. 7). The main controller 50 determines the X axis of the reticle stage 14 based on the measurement value of the reticle measurement system 56. The position (and speed) of the reticle stage 14 is controlled by calculating the position in the direction, the Y-axis direction, and the θz direction (rotation direction about the Z-axis) and controlling the reticle drive system 52 based on the calculation result. To do.

  The projection unit 16 is disposed below the reticle stage 14 in FIG. The projection unit 16 includes a lens barrel 16a and a projection optical system 16b composed of a plurality of optical elements held in the lens barrel 16a in a predetermined positional relationship. As the projection optical system 16b, a refractive optical system including a plurality of lenses (lens elements) having a common optical axis AX in the Z-axis direction is used. The projection optical system 16b is telecentric on both sides and has a predetermined projection magnification (such as 1/4, 1/5, or 1/8). Therefore, when the illumination area IAR on the reticle R is illuminated by the illumination light IL from the illumination system 12, the illumination light IL that has passed through the reticle R is illuminated via the projection optical system 16b (projection unit 16). A reduced image of the circuit pattern of the reticle R in the area IAR (a reduced image of a part of the circuit pattern) is conjugate to the illumination area IAR on the wafer W whose surface is coated with a resist (photosensitive agent) (hereinafter, “ (Also referred to as “exposure area”).

  The local liquid immersion device 18 (not shown in FIG. 1; see FIG. 7) includes a lowermost optical member (hereinafter referred to as a tip lens) constituting the projection optical system 16b and a wafer W (or a wafer W held on the wafer stage 24) (or This is an apparatus for locally filling a space (measuring stage 26) with a liquid (pure water) to form an immersion area. The local liquid immersion device 18 includes a liquid supply device, a liquid recovery device, a nozzle unit, various piping members (not shown), and the like, and circulates the liquid in the liquid immersion region, thereby allowing the wafer stage 24 and the measurement stage 26 to be circulated. Regardless of the position, the liquid is always held in the immersion area. In the exposure apparatus 10, the wafer W is exposed to the illumination light IL (passed through the immersion area) through the liquid. Since the immersion exposure method using the local immersion apparatus 18 is disclosed in US Pat. No. 8,004,650 and the like, detailed description thereof is omitted here.

  The stage apparatus 20 includes a base board 22, a wafer stage 24 disposed above the upper surface of the base board 22, a measurement stage 26, and a stage drive system 54 (not shown in FIG. 1) for driving the stages 24 and 26. 7), and a stage measurement system 58 (not shown in FIG. 1, refer to FIG. 7) for measuring the positions of the stages 24 and 26, and the like.

  The wafer stage 24 is mounted on the stage main body 24a and a Z / leveling mechanism (voice coil motor or the like) (not shown) on the stage main body 24a, and rotates about the Z-axis direction and the X-axis with respect to the stage main body 24a. A wafer table 24b that is relatively finely driven in the direction (θx direction) and the rotation direction around the Y axis (θy direction). A wafer holder (not shown) that holds the wafer W by vacuum suction or the like is disposed on the wafer table 24b. The upper surface of the wafer table 24b is substantially flush with the wafer held by the wafer holder, has a rectangular outer shape (contour), and a circular opening (see FIG. 2) that is slightly larger than the wafer holder at the center. The formed water repellent plate 24c is arranged.

  Further, as shown in FIG. 2, a measurement plate 24d is embedded on the water repellent plate 24c. A reference mark is formed at the center in the longitudinal direction of the measurement plate 24d, and a pair of aerial image measurement slit patterns are arranged symmetrically with respect to the center of the reference mark on one side and the other side of the reference mark in the X-axis direction. (L-shaped slit pattern) is formed. As the reference marks, lattice marks that can be detected by a primary alignment sensor 32p and a secondary alignment sensor 32s (see FIG. 1 respectively) described later are used.

  The measurement stage 26 is mounted on a stage body 26a and a Z / leveling mechanism (such as a voice coil motor) (not shown) on the stage body 26a, and rotates about the Z axis direction and the X axis with respect to the stage body 26a. And a measurement table 26b that is relatively minutely driven in the direction (θx direction) and the rotation direction around the Y axis (θy direction).

  The measurement stage 26 includes a sensor group 62 such as an illuminance unevenness sensor, a wavefront aberration measuring instrument, and an aerial image measuring instrument. The illuminance unevenness sensor and the wavefront aberration measuring instrument are disposed in the vicinity of the center of the measurement table 26b, and the illumination light IL (not shown in FIG. 2) via the projection optical system 16b and the liquid immersion region (liquid Lq). 1). Further, the aerial image measuring device has the wafer stage 24 and the measurement stage 26 approached (or contacted) within a predetermined distance with respect to the Y-axis direction via the slit pattern of the wafer stage 24 described above. The illumination light IL transmitted from is received. Various calibration operations of the illumination light IL using the sensor group 62 are disclosed in US Pat. No. 8,054,472 and the like, and thus detailed description thereof is omitted here.

  A fiducial bar (hereinafter abbreviated as “FD bar”) 28 as a reference member made of a rod-shaped member having a rectangular cross section is attached to the −Y side surface of the stage body 26a. The FD bar 28 is a member that functions as a master and is formed of a low thermal expansion material. A plurality of reference marks M are formed on the upper surface of the FD bar 28. As the reference mark M, a lattice mark that can be detected by a primary alignment sensor 32p and a secondary alignment sensor 32s described later is used. It is assumed that the positional relationship between the plurality of reference marks M is known.

  Each of the stage bodies 24a and 26a of the wafer stage 24 and the measurement stage 26 has a plurality of air bearings on the bottom surface. Each of the stage main bodies 24a and 26a floats in a non-contact manner above the upper surface of the base board 22 through a clearance of about several μm by the static pressure of the pressurized air ejected from the air bearing to the upper surface of the base board 22. doing. Each stage main body 24a, 26a can be driven independently in the Y-axis and X-axis directions along the upper surface of the base board 22 by a stage drive system 54 (see FIG. 7). In FIG. 7, an actuator for driving the stage bodies 24a and 26b in the XY biaxial directions, and a Z / leveling mechanism for minutely driving the tables 24b and 26b with respect to the stage bodies 24a and 26b. Including, it is shown as a stage drive system 54.

  In the stage device 20, the upper surface of the wafer table 24b and the upper surface of the measurement table 26b are in the same height and approached (or contacted) within a predetermined distance in the Y-axis direction (hereinafter referred to as a scrum state). Thus, the immersion area (liquid Lq) is transferred. That is, in the stage apparatus 20, each stage 24, 26 is moved from the state in which the liquid immersion area is formed between one of the wafer table 24 b and the measurement table 26 b and the projection optical system 16 b (tip lens) in the scrum state. By being driven in the axial direction, the state shifts to a state in which an immersion area is formed between the other of the wafer table 24b and the measurement table 26b and the projection optical system 16b. Since the mutual transfer operation of the liquid immersion area is disclosed in US Pat. No. 8,054,472 and the like, detailed description thereof is omitted here.

  In the stage apparatus 20, the structure of each stage 24, 26 is not limited to this, and can be changed as appropriate. That is, in each stage 24, 26, each table 24b, 26b is integrated with the corresponding stage main body 24a, 26a, and each of the integrated stage main bodies 24a, 26a has six degrees of freedom (X, Y, Z , Θx, θy, θz) directions. Further, the configuration of the stage drive system 54 (see FIG. 7) described above is not particularly limited, and an X linear motor and a Y linear motor as disclosed in US Pat. No. 8,054,472 are disclosed. A combined drive system can be used, and a drive system including a known XY two-dimensional planar motor can also be used.

  Further, the configuration of the stage measurement system 58 (see FIG. 7) described above is not particularly limited. As the stage measurement system 58, a measurement system including a two-dimensional encoder system, a measurement system including a laser interferometer system, a measurement system using both a two-dimensional encoder system and a laser interferometer system can be used. When an encoder system is used as a measurement system, an encoder scale (diffraction grating) is arranged on a measurement object (here, the wafer stage 24 and the measurement stage 26) and a predetermined fixing member (here, a projection unit). The metrology frame 16c (see FIG. 1) that supports the encoder 16 may be a system in which the encoder head is arranged. On the contrary, the encoder head is arranged on the measurement object, A system in which an encoder scale is arranged on a predetermined fixing member may be used. Further, when using a measurement system that uses both a two-dimensional encoder system and a laser interferometer system, the two-dimensional encoder system is used only in an area where the position of the measurement object needs to be measured with high accuracy. A system that uses a laser interferometer system in an area other than the measurable area of the system, or a system that uses both a two-dimensional encoder system and a laser interferometer system in the entire movable range of the measurement object. Also good.

  In addition, as a position measurement system in the Z-axis direction of the measurement object (here, the wafer stage 24 and the measurement stage 26), a system using a plurality of Z sensors including an optical displacement sensor configured as an optical pickup is used. A laser interferometer system may be used. When the position of the measurement object in the XY plane is measured using an encoder system, the measurement head (X head, Y head) of the encoder system is a two-dimensional head (XZ) capable of measuring the position in the Z-axis direction. A three-dimensional encoder system such as a head or a YZ head may be used. The above-described reticle measurement system 56 (see FIG. 7) can also use a measurement system similar to the stage measurement system 58.

  Next, the alignment system 30 including the alignment marks formed on the wafer W and off-axis type alignment sensors 32p and 32s used for detecting the alignment marks will be described.

  As an alignment mark to be detected by the alignment system 30, a lattice mark GM as shown in any of FIGS. 3A to 3C is formed in each shot region on the wafer W. At least one lattice mark GM is formed in the scribe line of each shot area.

  An example lattice mark GM shown in FIG. 3A includes an X lattice Gx and a Y lattice Gy. The X lattice Gx has a plurality of lattice lines parallel to the Y axis arranged at a predetermined pitch in the X axis direction, and the Y lattice Gy has a plurality of parallel to the X axis arranged at a predetermined pitch in the Y axis direction. Has grid lines. The grating mark GM moves relative to the illumination light L from the alignment sensors 32p and 32s (see FIG. 2) in the periodic directions (X-axis direction and Y-axis direction) of the gratings Gx and Gy (arrows in FIG. 3A). As a result, the X position and Y position of the lattice mark GM (that is, the wafer W (see FIG. 1)) are measured. In the example shown in FIG. 3A, the X lattice Gx and the Y lattice Gy are arranged at a predetermined interval in the X axis direction. However, the arrangement is not limited to this, and the X lattice Gx and the Y lattice Gy are arranged at a predetermined interval in the Y axis direction. May be arranged.

  Another example of the lattice mark GM shown in FIGS. 3B and 3C includes an α lattice Gα and a β lattice Gβ, respectively. The α lattice Gα is arranged at a predetermined pitch in a direction that forms an angle of 45 ° with respect to the X axis in the XY plane (hereinafter referred to as α direction in the coordinate system in the present embodiment). A plurality of lattice lines parallel to a direction orthogonal to the direction (also referred to as β direction), and β lattice Gβ includes a plurality of lattice lines arranged in a predetermined pitch in the β direction and parallel to the α direction. Have. In the lattice mark GM shown in FIG. 3B, the α lattice Gα and the β lattice Gβ are arranged side by side in the Y-axis direction. In the lattice mark GM shown in FIG. β lattices Gβ are arranged side by side in the X-axis direction. In the position measurement of the lattice mark GM shown in FIG. 3A described above, the lattice mark GM needs to be moved relative to the illumination light L in the X-axis direction and the Y-axis direction (that is, twice). In the position measurement of the lattice mark GM shown in FIGS. 3B and 3C, each lattice is moved by a single relative movement operation in the arrangement direction (Y-axis or X-axis direction) of each lattice Gα, Gβ. Position measurement of the mark GM in the α direction and β direction (that is, in the XY plane by calculation) can be performed.

  The type of the lattice mark GM formed on the wafer W (see FIG. 1) is not particularly limited, but in the present embodiment, the lattice mark GM shown in FIG. 3C is formed. Further, in FIGS. 3A to 3C, for the convenience of illustration, the pitch of the lattice is shown much wider than the actual pitch. The same applies to the diffraction gratings in the other figures. Further, in FIGS. 3A to 3C, the illumination light L is illustrated as being scanned with respect to the lattice mark GM, but actually, the irradiation point of the illumination light L being measured is measured. The position in the XY plane is fixed, and the lattice mark GM moves relative to the measurement beam irradiation point.

  As shown in FIG. 1, the alignment system 30 supplies measurement illumination light to the primary alignment sensor 32p and the secondary alignment sensor 32s arranged on the −Y side of the projection unit 16, and the alignment sensors 32s and 32p. A light source 34 (not shown in FIG. 1; see FIG. 4A, FIG. 7, etc.) is provided. As the light source 34, a combination of a plurality of laser diodes having different colors is used so that the overall wavelength range is about 200 to 1600 nm. The light source 34 may be individually provided in each of the alignment sensors 32p and 32s.

  As shown in FIG. 2, the alignment system 30 includes one primary alignment sensor 32p and six secondary alignment sensors 32s. The primary alignment sensor 32p is disposed at a position a predetermined distance away from the optical axis AX (see FIG. 1) of the projection optical system 16b on the −Y side, and is fixed to the lower surface of the metrology frame 16c (see FIG. 1). The detection visual field of the primary alignment sensor 32p is arranged on a straight line CL orthogonal to the optical axis AX of the projection optical system 16b and parallel to the Y axis. Of the six secondary alignment sensors 32s, three are arranged at a predetermined interval in the X-axis direction on the + X side of the primary alignment sensor 32p, and the remaining three are predetermined intervals in the X-axis direction on the −X side of the primary alignment sensor 32p. Is arranged in. The three secondary alignment sensors 32 s on the + X side and the secondary alignment sensor 32 s on the −X side are provided in a substantially symmetrical arrangement with respect to the straight line CL.

  Each secondary alignment sensor 32s can be independently driven with a predetermined stroke in the X-axis direction by an alignment drive system 36 (not shown in FIG. 2, see FIG. 7). The alignment drive system 36 fixes an actuator for driving each secondary alignment sensor 32s and each secondary alignment sensor 32s to the metrology frame 16c (see FIG. 1) (each secondary alignment sensor 32s on the metrology frame 16c). Holding mechanism). Thereby, in the alignment system 30, X position of the detection visual field of each secondary alignment sensor 32s can be adjusted separately (refer FIG. 5).

  Here, in the present embodiment, the alignment system 30 is a part of all shot areas (total 24 shots surrounded by a thick line in FIG. 5), as shown in FIG. The lattice mark GM formed in the region S) is set as a detection target. Hereinafter, the shot region S in which the lattice mark GM to be detected is formed will be referred to as a sample shot region S.

  In the present embodiment, the 24 sample shot regions S are divided into four groups having different positions in the Y-axis direction. Hereinafter, the four groups will be referred to as first to fourth groups in order from the + Y side. Each of the first to fourth groups includes a plurality of sample shot regions S (five in the first and fourth groups and seven in the second and third groups). The alignment system 30 is controlled to detect the lattice marks GM in a plurality (5 or 7) of sample shot regions S included in one group as few times as possible. That is, the alignment system 30 is controlled so as to collectively measure (simultaneously measure) a plurality (5 or 7) of lattice marks GM, if possible. A method for determining whether or not a plurality of lattice marks GM can be simultaneously measured will be described later.

  Next, the configuration and operation of each alignment sensor 32p, 32s will be described with reference to FIGS. 4 (a) and 4 (b). Note that the secondary alignment sensor 32s has the same configuration as that of the optical system, the detection method of the mark Mk, etc., except that the alignment drive system 36 (see FIG. 7) can be moved and positioned in the X-axis direction. It is substantially the same as the sensor 32p.

  As shown in FIG. 4A, the alignment sensors 32p and 32s include a beam splitter 40, objective lenses 42a and 42b, a fixed mirror 44, a plurality of detectors 46, and the like.

  The illumination light L emitted from the light source 34 enters the beam splitter 40, and the measurement light L1, which is a part of the illumination light L, passes through the objective lens 42a with respect to the lattice mark GM formed on the wafer W (see FIG. 2). Incident vertically. That is, in the alignment system 30, the light source 34 and the beam splitter 40 constitute an illumination system that irradiates the grating mark GM with the illumination light L. Here, each alignment sensor 32p, 32s is provided with a stop (not shown) on the optical path of the illumination light L emitted from the light source 34, and the diameter of the irradiation point on the lattice mark GM of the measurement light L1 by this stop ( As shown in FIGS. 3A to 3C, the spot diameter is set shorter than the length of the grid line. Therefore, there is little invalid light (wasted light that is not used for mark detection), and efficiency is high. The diaphragm may be disposed at a position optically conjugate with the surface of the wafer W (the position of the lattice mark GM).

  Further, the reference light L2, which is the other part of the illumination light L, enters the fixed mirror 44 perpendicularly via the objective lens 42b. The fixed mirror 44 is formed with a reflection type diffraction grating (not shown). The pitch of the diffraction grating formed on the fixed mirror 44 is set to be the same as the pitch of the grating marks GM formed on the wafer W. Hereinafter, the diffraction grating formed on the fixed mirror 44 will be referred to as a “reference grating” as appropriate.

A plurality of diffracted lights based on the measurement light L1 are generated from the lattice mark GM. A plurality of diffracted lights from the grating mark GM (+ N order diffracted light + Ld ₁ α from α grating Gα and −N order diffracted light −Ld ₁ α, + N order diffracted light + Ld ₁ β from β grating Gβ, And -N-order diffracted light -Ld ₁ β, where N is an integer of 1 or more, enters the plurality of detectors 46 through the objective lens 42 a and the beam splitter 40 (see FIG. 4B). When the measurement light L1 irradiates the α lattice Gα, ± Nth order diffracted light ± Ld ₁ α is generated, and when the measurement light L1 irradiates the β lattice, ± N next time Folding light ± Ld ₁ β is generated. In addition, a plurality of diffracted lights based on the reference light L2 are generated from the fixed mirror 44 (reference grating). A plurality of diffracted beams (+ N next plurality of diffracted light + Ld _2, and -N next plurality of diffracted beams _-ld 2 .N is an integer of 1 or more) from the fixed mirror 44, an objective lens 42b, and the beam splitter The light is incident on a plurality of detectors 46 through 40. The plurality of detectors 46 include photodiodes (not shown), and outputs thereof are supplied to the main controller 50 (see FIG. 7).

  Note that the beam splitter 40 may include a polarization beam splitter. At this time, a quarter-wave plate may be disposed in each of the optical path on the grating mark GM side and the optical path on the fixed mirror 44 side of the polarization beam splitter.

  Here, in the alignment sensors 32p and 32s, diffracted light in a specific direction generated from the grating mark GM and the fixed mirror 44, specifically, a pair of diffracted lights of the same order (+ Nth order diffracted light and −Nth order diffracted light). They interfere with each other at the beam splitter 40. Since a pair of diffracted lights of the same order have the same diffraction angle, the depth of focus (DOF) of the optical system of the alignment sensors 32p and 32s can be increased. That is, if a pair of diffracted light beams having different diffraction orders (diffraction angles) are caused to interfere with each other, the ideal imaging position (best focus position) is different (shifted) with respect to the optical axis direction. Easy (DOF is narrow). On the other hand, in the present embodiment, diffracted lights of the same order, that is, lights in a specific direction are caused to interfere with each other, so that the DOF can be widened (for example, about several μm). In addition, since only light in a specific direction is used, only specific portions are used for the objective lenses 42a and 42b. In other words, light passes only through a specific part of the objective lens 42. Accordingly, it is only necessary to correct the aberration with respect to only the light passing through the specific optical path, so that the objective lenses 42a and 42b can be downsized and the NA can be increased.

  As an example, a signal (interference signal) having a waveform as shown in FIG. 6 is obtained from the output of the detector 46. The main controller 50 (see FIG. 7) determines the lattice mark GM (X lattice Gx, Y lattice Gy, α lattice Gα, β lattice Gβ, respectively) from the phase of the signal as shown in FIG. (See FIG. 3C) Each position is obtained by calculation. Thereby, the position of the lattice mark GM on the XY two-dimensional coordinate system is obtained.

  More specifically, the rough position of the lattice mark GM can be obtained from the position of the edge portion of the waveform shown in FIG. 6 (the portion where the waveform rises at both ends in the horizontal axis direction), and the waveform is a sine wave. The detailed position of the lattice mark GM can be obtained from the phase of the shape portion. Therefore, the wafer search alignment can be performed from the rough position information, and the wafer fine alignment can be performed from the detailed position information. Further, the diffraction efficiency of the grating mark GM (diffraction grating) can be found from the amplitude of the portion having the sine wave shape. As described above, in the exposure apparatus 10 (see FIG. 1) of the present embodiment, the alignment system 30 (the light source 34 and the alignment sensors 32p and 32s) and the main controller 50 (see FIG. 7 respectively) are formed on the wafer W. An alignment device (grid mark GM position measuring device) for determining the position information of the lattice mark GM is configured.

  Each alignment sensor 32p, 32s (see FIG. 2) has an alignment autofocus (alignment AF) system 38 (see FIG. 7). The alignment AF system 38 is a mechanism that automatically controls (adjusts) the optical system so that the lattice mark GM is positioned within the detection range (depth of focus) in the Z-axis direction of the objective optical system in each of the alignment sensors 32p and 32s. have. Here, since the alignment AF system 38 has the optical systems of the alignment sensors 32p and 32s independently, the alignment sensor 32p and 32s may be used to measure the surface shape (unevenness etc.) of the surface of the wafer W. Is possible. Details of the alignment AF system 38 can be referred to, for example, US Pat. No. 5,783,833.

  The exposure apparatus 10 has an autofocus system (AF system) 64 (see FIG. 7) separately from the alignment AF system 38 described above. The AF system 64 includes an oblique incidence type multi-point focus position detection device as disclosed in US Pat. No. 5,448,332 and US 2012/0008150. A band-shaped detection area extending in the X-axis direction is formed on the wafer W, and the surface position of the wafer W (irregularity, flatness, etc. on the surface of the wafer W) in the detection area is measured.

  FIG. 7 is a block diagram showing the main configuration of the control system in the exposure apparatus 10. The control system includes a so-called microcomputer (or workstation) composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and controls the entire system. The main controller 50 is mainly configured.

  Next, the calibration operation of the alignment system 30 performed by the exposure apparatus 10 (see FIG. 1) of the present embodiment and the wafer alignment operation using the alignment system 30 will be described with reference to FIGS. To do. The following calibration operation and wafer alignment operation are performed under the control of the main controller 50 (see FIG. 7). 8 to 11D, the main controller 50 is not shown.

  In the exposure apparatus 10 (see FIG. 1), the calibration operation of the alignment system 30 is performed before the wafer alignment operation. The calibration operation includes baseline measurement of each alignment sensor 32p, 32s. Here, the baseline of the primary alignment sensor 32p means the positional relationship (or distance) between the projection position of the pattern (reticle R pattern) by the projection optical system 16b and the detection center of the primary alignment sensor 32p. In the wafer alignment operation and calibration operation described below, each secondary alignment sensor 32s is adjusted in advance in the X-axis direction according to the arrangement of the sample shot regions S (see FIG. 5). It shall be.

  At the time when baseline measurement of the primary alignment sensor 32p is started, as shown in FIG. 8A, a liquid immersion region (hereinafter, referred to as a liquid immersion region) is formed between the projection optical system 16b and the measurement stage 26 (FD bar 28). The same reference numeral as that of the liquid Lq is given, and the liquid immersion region Lq will be described). Further, the wafer stage 24 and the measurement stage 26 are in a separated state. Main controller 50 detects a reference mark (not shown) formed on measurement plate 24d on wafer table 24b by primary alignment sensor 32p. Further, main controller 50 associates the detection result of primary alignment sensor 32p with the measurement value of stage measurement system 58 (see FIG. 7) at the time of detection and stores it in a memory (not shown). Hereinafter, this process is referred to as the first half of Pri-BCHK for convenience.

  Next, as shown in FIG. 8B, the main controller 50 controls the position of the wafer stage 24 so that the measurement plate 24d is positioned immediately below the projection optical system 16b. At this time, the immersion area Lq is transferred from the FD bar 28 to the wafer table 24b by integrally moving in the Y-axis direction while the measurement stage 26 and the wafer stage 24 are in contact with each other or close to each other. . Further, the main controller 50 measures the projection image (aerial image) of the measurement mark on the reticle R (see FIG. 1) projected by the projection optical system 16b by using the aerial image measuring instrument described above, and the measurement. Remember the result. Hereinafter, the measurement processing of the projected image of the measurement mark on the reticle R will be described as the latter half of Pri-BCHK for convenience. Then, main controller 50 calculates the baseline of primary alignment sensor 32p based on the result of the first half of Pri-BCHK and the result of the second half of Pri-BCHK.

  Next, the baseline measurement operation of the secondary alignment sensor 32s, which is performed immediately before starting the processing on the wafers of each lot (the lot head), will be described. Here, the baseline of the secondary alignment sensor 32s means the relative position of the detection center of each secondary alignment sensor 32s with reference to the detection center of the primary alignment sensor 32p.

  In the baseline measurement of the secondary alignment sensor 32s (hereinafter also referred to as Sec-BCHK as appropriate), the main controller 50 performs a specific process on the wafer W (process wafer) at the head of the lot as shown in FIG. The lattice mark GM is detected by the primary alignment sensor 32p, and the detection result and the measurement value of the stage measurement system 58 (see FIG. 7) at the time of detection are stored in association with each other. Further, the main controller 50 appropriately drives the wafer stage 24 to detect the specific lattice mark GM with each secondary alignment sensor 32s, as shown in FIG. The measurement values of the stage measurement system 58 at the time of detection are stored in association with each other. Main controller 50 calculates the baseline of each secondary alignment sensor 32s based on the stored data.

  As described above, in this embodiment, by using the wafer W (process wafer) at the head of the lot, the same alignment mark on the wafer W is detected by the primary alignment sensor 32p and each secondary alignment sensor 32s. Since the baseline of each secondary alignment sensor 32s is obtained, as a result, the difference in detection offset between the alignment sensors due to the process is also corrected.

  Next, during processing within a lot, for example, Sec performed during a period from the completion of exposure of a wafer W to the completion of loading of the next wafer W onto the wafer table 24b, that is, during wafer replacement. -The operation of BCHK will be described. Since Sec-BCHK in this case is performed at intervals of every wafer exchange, it is also described below as Sec-BCHK (interval).

  During Sec-BCHK (interval), main controller 50 causes primary alignment sensor 32p to detect a mark in the vicinity of the center among a plurality of marks formed on FD bar 28, as shown in FIG. In this state, main controller 50 obtains the baseline of each secondary alignment sensor 32s by causing each secondary alignment sensor 32s to simultaneously detect a mark in the field of view. In this way, by performing Sec-BCHK at an interval of every wafer exchange, it is possible to correct the influence of the baseline of each secondary alignment sensor 32s. In the above description, each secondary alignment sensor 32s has been described as simultaneously detecting a mark in the field of view. However, the present invention is not limited to this, and each secondary alignment sensor 32s sequentially detects the same mark on the FD bar 28. Also good.

  Next, a wafer alignment operation using the alignment system 30 will be described with reference to FIGS. 11 (a) to 11 (d). As described above, the 24 sample shot areas S set on the wafer W are divided into the first to fourth groups, and the wafer alignment operation is sequentially performed from the first group on the most + Y side. Note that when detecting the lattice mark GM belonging to the first and fourth grooves, the secondary alignment sensor 32s on the most + X side and the most -X side is not used.

  When the wafer W is loaded onto the wafer stage 24 (see FIG. 1) at a predetermined loading position, the main controller 50 loads the stage measurement system 58 (see FIG. 7) as shown in FIG. Based on the output, the wafer stage 24 is appropriately driven in the X-axis and Y-axis directions to position the wafer W at the first group alignment start position.

  In the alignment system 30 of the present embodiment, the wafer W is relatively moved in a predetermined scanning direction (Y-axis direction in the present embodiment) with respect to the illumination light L irradiated from the alignment sensors 32p and 32s from the alignment start position. (See FIG. 3C), the lattice marks GM formed in the five sample shot regions included in the first group are simultaneously detected. Main controller 50 associates and stores the detection results of five lattice marks GM included in the first group and the measurement values of stage measurement system 58 (see FIG. 6) at the time of detection.

  Next, as shown in FIG. 11B, the main controller 50 drives the wafer stage 24 in the Y-axis direction based on the measurement value of the stage measurement system 58 (see FIG. 7). The alignment sensors 32p and 32s position the lattice marks GM formed in the seven sample shot regions S belonging to the second group on the wafer W at positions where they can be detected almost simultaneously and individually. Each of the seven alignment sensors 32p and 32s detects the corresponding seven lattice marks GM almost simultaneously and individually, and the main controller 50 detects the detection results of the seven alignment sensors 32p and 32s and the stage at the time of the detection. The measurement values of the measurement system 58 are stored in association with each other.

  Next, as shown in FIG. 11C, the main controller 50 drives the wafer stage 24 in the Y-axis direction based on the measurement value of the stage measurement system 58 (see FIG. 7), and The alignment sensors 32p and 32s position the lattice marks GM formed in the seven sample shot regions S belonging to the third group on the wafer W at positions where they can be detected almost simultaneously and individually. Each of the seven alignment sensors 32p and 32s detects the corresponding seven lattice marks GM almost simultaneously and individually, and the main controller 50 detects the detection results of the seven alignment sensors 32p and 32s and the stage at the time of the detection. The measurement values of the measurement system 58 are stored in association with each other.

  Next, main controller 50 drives wafer stage 24 in the Y-axis direction based on the measurement value of stage measurement system 58 (see FIG. 7), as shown in FIG. The alignment sensors 32p and 32s position the lattice marks GM formed in the five sample shot regions S belonging to the fourth group on the wafer W at positions where they can be detected almost simultaneously and individually. Each of the five alignment sensors 32p and 32s detects the corresponding seven lattice marks GM almost simultaneously and individually, and the main controller 50 detects the detection results of the five alignment sensors 32p and 32s and the stage at the time of the detection. The measurement values of the measurement system 58 are stored in association with each other.

  Then, the main controller 50 uses the detection results of the total 24 lattice marks GM obtained in this way and the measurement values of the corresponding stage measurement system 58 (see FIG. 7) to obtain US Pat. All shots on the wafer W on the coordinate system defined by the measurement axis of the stage measurement system 58 by performing statistical calculation (so-called EGA (Enhanced Global Alignment)) disclosed in the specification of 780,617, etc. Calculate the array of regions. Thereafter, main controller 50 performs a step-and-scan scanning exposure operation on each shot area while appropriately positioning reticle R and wafer W within the XY plane based on the array coordinates. Since this scanning exposure operation is the same as a conventional step-and-scan type scanning exposure operation, the description thereof is omitted.

  Thus, in this embodiment, 5 or 7 lattice marks GM belonging to each of the first to fourth groups having different Y positions can be collectively detected. Accordingly, the detection operation of a total of 24 lattice marks GM can be completed by a total of 4 detection operations, and the shot area is remarkably shortened compared to the case where 24 lattice marks GM are individually detected. Can be calculated.

  Here, in order to detect a plurality (5 or 7) of lattice marks GM simultaneously and with high accuracy, the target lattice mark GM is positioned within the depth of focus (DOF) of each alignment sensor 32p, 32s. Need to be. On the other hand, the surface of the wafer W is not an ideal plane and usually has some unevenness. Therefore, when the plurality of lattice marks GM are simultaneously detected by the alignment sensors 32p and 32s, at least a part of the alignment sensors is highly likely to detect the lattice marks GM in a defocused state.

  In such a case, it is conceivable that the position of the wafer table 24b in the Z-axis direction is appropriately changed so that the lattice mark GM is positioned within the DOF of each of the alignment sensors 32p and 32s. If the DOF varies between the two, and the number of sensors is large as in the present embodiment, the number of Z drives of the wafer table 24b increases, which may cause a reduction in throughput.

  Therefore, in the present embodiment, the number of detections of the lattice mark GM is reduced and the decrease in throughput is suppressed by the procedure described below. Hereinafter, a simultaneous multi-view detection operation of a plurality of lattice marks GM belonging to each of the first to fourth groups using the alignment system 30 will be described using the flowchart shown in FIG. The following control is performed under the management of the main controller 50 (see FIG. 7; not shown in the following description).

  In step S10, main controller 50 measures the surface shape of wafer W using alignment AF system 38 (see FIG. 7) included in each of alignment sensors 32p and 32s described above. Here, the shape of the wafer W is not the surface shape of the entire wafer W, but the XZ of the wafer W passing through a line parallel to the X axis passing through a plurality of (5 or 7) lattice marks GM to be simultaneously measured. It means the shape in the cross section. Accordingly, the wafer shape is output as seven values in the Z-axis direction.

  Here, as described above, the alignment sensors 32p and 32s are attached to the metrology frame 16c (see FIG. 1) at predetermined intervals in the X-axis direction independently of each other. is there. Therefore, main controller 50 determines in step S12 the wafer shape (value in the Z-axis direction) obtained in step S10 and the height position (ALG height position) of each alignment sensor 32p, 32s used for measurement. Find the difference. Thereby, the output of each alignment AF system 38 is corrected, and the actual surface height position of the wafer W can be obtained. In addition, the height position of each alignment sensor 32p and 32s shall be known. The graph of FIG. 13 shows the surface height position of the wafer W at each measurement point obtained in step 12 above.

  Next, in step S14, main controller 50 performs a primary approximation formula (in FIG. 13) based on the data of the surface height position of wafer W at each measurement point obtained in step S12 by calculation (primary fitting). A straight line Ap) in the graph is obtained. The inclination of the linear approximation formula is used for attitude control in the tilt direction (tilt direction) of the wafer W during the simultaneous multi-eye detection operation using the sensors 32p and 32s.

  Further, in step S16, main controller 50 obtains the maximum value (Δmax) and the minimum value (Δmin) of the difference between straight line Ap (primary approximation formula) and each plot (actual measurement value) from the graph of FIG. In addition, in the graph of FIG. 13, the coordinate value in the Z-axis direction where Δmax = Δmin is obtained by moving the straight line Ap in the vertical axis direction. This Z coordinate value is used for controlling the height position of the wafer W during the simultaneous multi-eye detection operation using the sensors 32p and 32s.

  Next, in step S18, main controller 50 obtains deviation amount Δ in a state where the posture of wafer W is removed. Here, the orientation of the wafer W means the slope of the first-order approximation formula (straight line Ap in FIG. 13) obtained in step S12, and the deviation amount Δ is the straight line Ap in the graph of FIG. And Δmin) means the defocus amount with respect to the wafer W surface of the alignment sensors 32p and 32s corresponding to the plot.

  Next, in step S20, main controller 50 determines whether or not the deviation amount Δ obtained in step S18 is within the DOF of the corresponding alignment sensors 32p and 32s. In addition, DOF of each alignment sensor 32p and 32s shall be known. When the deviation amount Δ is within the DOF range, the process proceeds to step S22, and when the deviation amount Δ is outside the DOF range, the process proceeds to step S24.

  In step S22, main controller 50 positions wafer stage 24 based on the slope of the linear function (straight line Ap in FIG. 13) obtained in step S14 and the coordinate value in the Z-axis direction obtained in step S16. And the Z position and the tilt amount of the surface of the wafer W are adjusted. Since the deviation amount Δ is within the DOF range of the alignment sensors 32p and 32s in the state in which the attitude of the wafer stage 24 is controlled (Yes in step S20), all the alignment sensors 32p and 32s are detected. As a result, the grid mark GM is located in the DOF. Therefore, main controller 50 can simultaneously measure five or seven lattice marks GM. The main controller 50 uses the alignment sensors 32p and 32s to simultaneously measure the lattice mark GM to be detected, and ends the process.

  On the other hand, when the divergence amount Δ is out of the DOF range (No determination in step S20), the alignment marks 32G and 32s in some of the alignment sensors 32p are located outside the DOF. Alternatively, simultaneous (collective) measurement of seven lattice marks cannot be performed. Therefore, main controller 50 groups each plot into two in step S24. Here, the difference Δ between the straight line Ap (approximate expression) and each plot (measured value) is grouped according to plus (Δ> 0) and minus (Δ <0). That is, in the graph of FIG. 13, grouping is performed into a plot group on the + side and a plot group on the − side with respect to the straight line Ap in the vertical axis direction. Thereafter, main controller 50 returns to step S14 for each group (step S26), and repeats the processing after step S14.

  Main controller 50 repeats the processes of steps S10 to S26 shown in FIG. 12 for each of the first to fourth groups, so that a total of 24 positions of lattice marks GM belonging to the first to fourth groups are obtained. In addition to performing measurement, an array of all shot areas on the wafer W is calculated based on the measurement result of the 24 lattice marks GM. The wafer shape measurement in step S10 may use the AF system 64 (see FIG. 7) instead of the alignment AF system 38. Further, the wafer shape measurement in step S10 may be performed using an external measuring device different from the exposure apparatus 10.

  Here, as described above, the alignment sensors 32p and 32s of the present embodiment cause the diffracted light generated from the grating mark GM and the reference light generated from the fixed mirror 44 to interfere with each other in the optical system, so As shown in FIG. 14, when the fixed mirror 44 (grating surface on which the reference grating is formed) is inclined and the telecentricity of the optical system is lowered, as shown in FIG. Doing so will cause alignment measurement errors. In order to avoid this, main controller 50 corrects the outputs of alignment sensors 32p and 32s according to the telecentricity of the optical system of alignment sensors 32p and 32s.

  The telecentricity of the optical system of the alignment sensors 32p and 32s is measured using the above-described stage measurement system 58 (see FIG. 7). Specifically, the amount of alignment measurement value deviation corresponding to the amount of positional deviation of the wafer stage 24 in the Z-axis direction is measured using a stage measurement system 58 including an encoder system (or optical interferometer system). The measurement result is stored in a storage device (not shown) as correction data. That is, the stage measurement system 58 also functions as a measurement unit that measures the telecentricity of the optical system of the alignment sensors 32p and 32s. At the time of actual alignment measurement, the alignment AF system 38 is used to measure the defocus amounts of the alignment sensors 32p and 32s (difference between the straight line Ap and each plot in the graph of FIG. 13), and according to the defocus amount. Then, the alignment measurement result is corrected based on the correction data. As a result, even if the wafer stage 24 moves in the Z-axis direction during the alignment measurement or the surface of the wafer W is uneven, the alignment measurement is caused by a decrease in the telecentricity of the optical system of the alignment sensors 32p and 32s. As a result, it is possible to correct an error in the result, and it is possible to suppress an increase in the size of the sensor as compared with a case where an adjustment mechanism is provided in the sensor so that the alignment sensors 32p and 32s do not perform measurement in a defocused state.

<< Second Embodiment >>
Next, an alignment sensor 132 according to the second embodiment will be described with reference to FIGS. 15 (a) and 15 (b). Since the configuration of the alignment sensor 132 according to the second embodiment is the same as that of the first embodiment except that the configuration of the optical system is different, only the differences will be described below, and the first embodiment will be described. Elements having the same configuration and function as those of the embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted. The same applies to third and fourth embodiments described later. In addition, the alignment sensor 132 according to the second embodiment can be used as a primary alignment sensor whose position in the XY plane is fixed or a secondary alignment sensor whose position is movable in the XY plane. The same applies to alignment sensors according to third and fourth embodiments described later. The type of lattice mark GM formed on the wafer W is not particularly limited, but in the second embodiment and third and fourth embodiments described later, the lattice mark GM shown in FIG. Is formed.

  In alignment sensor 132, illumination light L from a light source (not shown) enters beam splitter 140. The beam splitter 140 emits a pair of illumination lights L1 and L2. The illumination lights L1 and L2 are incident on the beam splitter 40 through the lens 142 as in the first embodiment. The measurement lights L1A and L2A that are parts of the illumination lights L1 and L2 pass through different positions of the objective lens 42a and enter the grating mark GM. Here, the measurement lights L1A and L2A are incident obliquely from opposite directions to the normal direction (Z-axis direction) of the surface of the wafer W, respectively (see FIG. 15B). The diffracted lights L1Ad and L2Ad from the grating mark GM based on the measurement lights L1A and L2A pass through the objective lens 42a and the beam splitter 40, respectively, and enter the plurality of detectors 46.

  Note that the beam splitter 140 may include a polarization beam splitter. At this time, a quarter-wave plate may be disposed in each of the optical path on the grating mark GM side and the optical path on the fixed mirror 44 side of the polarization beam splitter.

  The reference lights L1B and L2B, which are the other parts of the illumination lights L1 and L2, pass through different positions of the objective lens 42b and enter the fixed mirror 44. Here again, the reference beams L1B and L2B are incident obliquely from opposite directions with respect to the normal direction (X-axis direction) of the lattice plane of the fixed mirror 44, respectively. The diffracted lights L1Bd and L2Bd from the fixed mirror 44 based on the reference lights L1B and L2B pass through the objective lens 42a and the beam splitter 40, respectively, and enter the plurality of detectors 46. The plurality of detectors 46 is based on the interference between the diffracted light from the grating mark GM and the diffracted light from the fixed mirror 44 (interference between the diffracted lights L1Ad and L2Bd and interference between the diffracted lights L2Ad and L1Bd). Detects the positional deviation of. In the alignment sensor 132 according to the second embodiment, since the measurement lights L1A and L2A are incident obliquely on the grating mark GM, a diffraction grating having a narrower pitch than that of the first embodiment is formed. Since the lattice mark can be detected, the detection accuracy of the lattice mark GM is improved.

  In addition, the alignment sensors 32p, 32s, and 132 of each of the embodiments described above are fixed mirrors that include a reflective diffraction grating (reference grating) as a reference light generating member that generates reference light that interferes with the diffracted light from the grating mark GM. However, the reference light generating member is not limited to this, and an SLM (Spatial Light Modulator), an AOM (Acoustic Optical Modulator), or the like may be used.

  In addition, a two-dimensional diffraction grating may be used as a reflection type diffraction grating as a reference light generating member in the alignment sensors 32p, 32s, 132 of each of the above embodiments. The two-dimensional diffraction grating may have a pitch direction corresponding to each of the pitch direction of the α grating Gα and the pitch direction of the β grating Gβ of the grating mark GM. The reference light generating member may be a scattering surface that scatters incident light. As the scattering surface, the emitted light may be scattered within a predetermined angle range. As described above, when a member that emits light over a predetermined angle range is used as the reference light generating member, there is an advantage that detection is possible even if the pitch of the lattice mark GM is an arbitrary pitch.

<< Third Embodiment >>
Next, an alignment sensor 232 according to a third embodiment will be described with reference to FIGS. 16 (a) and 16 (b). The alignment sensor 232 is an illumination type that supplies illumination light L to an optical system including the beam splitter 40 and the objective lens 242, and has a fixed mirror 240. The fixed mirror 240 has a transmissive diffraction grating, and measurement light L1 and L2 which are diffracted lights based on the illumination light L1 are emitted from the fixed mirror 240. As in the second embodiment, the measurement lights L1 and L2 are incident on the beam splitter 40, and are obliquely incident on the grating mark GM through different positions of the objective lens 42a. In the grating mark GM, zero-order diffracted light (reflected light) L1r and L2r and first-order diffracted lights L1d and L2d of the measurement lights L1 and L2 are generated, respectively. Then, the light passes through the objective lens 42a and the beam splitter 40 and enters the pair of detectors 46 (see FIG. 16B). The pair of detectors 46 detect the positional deviation of the grating mark GM based on the interference between the 0th-order light L1r and the diffracted light L2d and the interference between the 0th-order light L2r and the diffracted light L1d. In the third embodiment, as in the second embodiment, the measurement lights L1 and L2 are obliquely incident on the grating mark GM, so that a diffraction grating with a narrower pitch can be detected.

<< Fourth Embodiment >>
Next, an alignment sensor 332 according to a fourth embodiment will be described with reference to FIGS. 17 (a) and 17 (b). The alignment sensor 332 is a so-called self-reference type alignment sensor. The illumination light L emitted from the light source 34 has its optical path bent by a mirror 340, and the lattice mark GM is the same as in the first embodiment (FIG. 4). (See (a)), the light passes through (transmits) the center of the objective lens 42 and is incident substantially perpendicularly, and a plurality of diffracted lights + Ld and -Ld based on the illumination light L are generated from the grating mark GM. The plurality of ± Nth order diffracted lights ± Ld that have passed through the objective lens 42 enter the interferometer 344. The interferometer 344 has a function similar to that of the interferometer disclosed in US Pat. No. 6,961,116, and −Nth order diffracted light from the grating mark GM + Ld from the grating mark GM. The Nth order diffracted light -Ld is superimposed at a predetermined mixing ratio, and the + Nth order diffracted light + Ld from the grating mark GM is superimposed at a predetermined mixing ratio on the -Nth order diffracted light -Ld from the grating mark GM. The interferometer 344 divides incident ± Nth order diffracted light, and the divided one optical path and the other optical path are relatively 180 degrees (180 degrees ± n × 360 degrees: n is an integer) relative to the optical axis. Synthesize after rotating. Note that the interferometer 344 may be referred to as a self-referencing interferometer. The light beam emitted from the interferometer 344 enters a pair of detectors 46 arranged on the pupil plane 48 (aperture position). The pair of detectors 46 detects the positional deviation of the grating mark GM based on the interference between the diffracted lights.

  The configurations of the first to third embodiments are examples, and can be changed as appropriate. That is, the number and arrangement of alignment sensors are not limited to the above embodiments, and the number of secondary alignment sensors 32s is six in the above embodiment, but may be less than six or seven. It may be above. Moreover, in the said embodiment, the space | interval between a pair of adjacent secondary alignment sensors 32s can also be set arbitrarily. Further, the number and arrangement of the sample shot areas S to be detected are not limited to those described in the above embodiment, and can be arbitrarily set. If possible, all shots formed on the wafer W can be set. The area may be set to the sample shot area S. A plurality of lattice marks GM formed in one sample shot area may be detected.

  The alignment sensors 32p, 32s, 132 of the first and second embodiments are reflective diffraction gratings (reference gratings) as reference light generating members that generate reference lights that interfere with the diffracted lights from the grating marks GM. However, the reference light generating member is not limited to this, and an SLM (Spatial Light Modulator), an AOM (Acoustic Optical Modulator), or the like may be used.

  Further, a two-dimensional diffraction grating may be used as a reflection type diffraction grating as a reference light generating member in the alignment sensors 32p, 32s, 132 of the first and second embodiments. The two-dimensional diffraction grating may have a pitch direction corresponding to each of the pitch direction of the α grating Gα and the pitch direction of the β grating Gβ of the grating mark GM. The reference light generating member may be a scattering surface that scatters incident light. As the scattering surface, the emitted light may be scattered within a predetermined angle range. As described above, when a member that emits light over a predetermined angle range is used as the reference light generating member, there is an advantage that detection is possible even if the pitch of the lattice mark GM is an arbitrary pitch.

  In each of the above embodiments, a plurality of detectors 46 are provided. However, a single detector having a plurality of detection surfaces for detecting light independently of each other may be used.

<< Fifth Embodiment >>
Further, in addition to the measurement of the position of the lattice mark GM in the XY plane, a measurement value related to the feature of the lattice mark GM may be obtained using the alignment system 30.

  Specifically, the alignment system 30 is referred to as a predetermined measurement value (hereinafter referred to as “scattering measurement value”) by a so-called scatterometry method (light wave scattering measurement method) based on a plurality of diffracted lights from the grating mark GM. And the symmetry of the shape with respect to the periodic direction of the lattice mark GM is obtained based on the scatterometry measurement value. That is, as shown in FIG. 4A, the diffraction grating of the grating mark GM is formed in a shape in which irregularities are continuous in the periodic direction. When the measurement light L1 is applied to the diffraction grating, as shown in FIG. 18A, the symmetry of the shape of the grating mark GM is ensured with respect to the optical axis center of the measurement light L1. Are symmetric (same) in the intensity and phase of the + Nth order (N = 1 to 3 in FIG. 18A) and the −Nth order diffracted light from the grating mark GM. Here, in FIGS. 18A and 18B, the thickness of each arrow indicates the intensity of light, and the length of each arrow indicates the phase of light.

  On the other hand, when the symmetry of the shape of the lattice mark GM is impaired with respect to the periodic direction, as shown in FIG. 18B, + N order (N = 1 to 3 in FIG. 18B). ) The intensity and phase of the diffracted light and the -Nth order diffracted light are asymmetric.

  As described above, the alignment sensors 32p and 32s generate waveform signals as shown in FIG. The vertical axis of the coordinate system of the waveform signal represents the light amount, and the amplitude of the waveform represents the diffraction efficiency. That is, the intensity and phase of the diffracted light from the grating mark GM are reflected in the waveform signal generated based on the output of each detector 46, and thereby the period of the shape of the grating mark GM is generated from the waveform signal. The symmetry with respect to the direction can be estimated.

  The main controller 50 obtains a waveform signal as shown in FIG. 6 from the alignment sensors 32p and 32s for each of the plurality of lattice marks GM, and based on the waveform signal, each of the plurality of lattice marks GM. By comparing these waveform signals, it is possible to select the lattice mark GM having the most stable shape (excellent symmetry) among the plurality of lattice marks GM.

  As described above, in the present embodiment, it is possible to select the lattice mark GM and the illumination light for mark detection that are optimal for use in wafer alignment by using the alignment sensors 32p and 32s. The symmetry of the shape of the lattice mark GM has a great influence on the position measurement accuracy of the lattice mark GM. Therefore, when the position of the lattice mark GM is measured, the selected lattice mark GM (having the highest shape symmetry). By using the lattice mark GM), the position information of the lattice mark GM can be obtained with higher accuracy. Further, the positioning accuracy of the wafer W during wafer alignment is improved.

  Further, as described above, the alignment sensors 32p and 32s of the present embodiment can irradiate a plurality of lights (lasers) having different wavelengths as the illumination light L. The main controller 50 irradiates the selected grating mark GM with a plurality of lights having different wavelengths, and acquires a waveform signal as shown in FIG. 6 based on each of the plurality of lights. Then, main controller 50 can select light having a wavelength most suitable for wafer alignment from among the plurality of lights by comparing the waveform signals for each of the plurality of lights.

  In addition, for the estimation (measurement) of the symmetry (or asymmetry) of the shape of the lattice mark GM by the scatterometry method described above, the measurement light L1 is applied to the lattice mark GM using the alignment sensors 32p and 32s. Therefore, the position measurement operation of the lattice mark GM in the XY coordinate system and the symmetry estimation (measurement) operation of the shape of the lattice mark GM can be performed simultaneously. Therefore, the shape of the lattice mark GM can be estimated without affecting the throughput.

  In the present embodiment, the error of the alignment measurement result generated based on the shape asymmetry of the grating mark GM with respect to the periodic direction described above is based on the scatter measurement value (the intensity ratio of the pair of diffracted lights from the grating mark GM). Main controller 50 (see FIG. 7; not shown in the following description) corrects. Hereinafter, this correction method will be described with reference to the flowchart of FIG.

  In step S510, main controller 50 performs lattice mark GM (FIG. 3A to FIG. 3) formed on the first (lot leading) wafer W in one lot (see FIG. 1, not shown in the following description). (Refer to (c), which is not shown in the following description) is detected by the procedure described above (FIGS. 11A to 11D). The detection operation of the plurality of lattice marks GM includes measurement of position information of each lattice mark GM in the XY plane and measurement of a measurement value of a scatter measurement value. As described above, the asymmetry (mark feature) of the lattice mark GM can be estimated from the scatterometry measurement value.

  Here, as described above, if the shape of the lattice mark GM is asymmetric, an error is caused in the alignment measurement result, in other words, the alignment measurement result caused by the mark feature of the lattice mark GM is deceived. Therefore, main controller 50 corrects the distortion of the alignment measurement result based on the scatter measurement value in step S512. In this correction process, a predetermined correction coefficient obtained using the graph shown in FIG. 20 is used. In the graph of FIG. 20, the horizontal axis represents the scatter measurement value, and the vertical axis represents the overlap measurement result. Here, the overlap measurement result on the vertical axis means the position of each lattice mark GM when another lattice mark GM is formed on the existing lattice mark GM by overlapping based on the position measurement result of the lattice mark GM. This means the amount of deviation and is obtained in advance using a CD-SEM or the like. As shown in FIG. 20, since the overlay measurement error according to the scatter measurement value can be obtained in advance based on the correlation between the scatter measurement value and the overlap measurement value, the scatter measurement value obtained in step S510 and From the above correlation (a straight line shown in the graph of FIG. 20), the overlay measurement error can be predicted. Therefore, main controller 50 corrects the alignment measurement result obtained in step S510 so as to cancel the predicted overlay measurement error using the correction coefficient obtained based on the correlation.

  Returning to FIG. 19, main controller 50 calculates an array of all shot regions on wafer W by EGA calculation based on the alignment measurement result after correction (position information of lattice mark GM) in step S514. In step S516, a new pattern is formed on the existing pattern formed on the wafer W by a step-and-scan exposure operation while controlling the position of the wafer W based on the result of the EGA calculation.

  The wafer W that has been subjected to the exposure processing in step S516 is sent to an optical overlay measuring apparatus 800 (inline overlay measuring instrument 800) provided in the exposure apparatus 10 (see FIG. 7). The overlay accuracy between the pattern formed in step S516 and the existing pattern is measured. As the inline overlay measuring instrument 800, as in the alignment sensors 32p and 32s described above (see FIG. 4 (a)), so-called DBO (Diffraction Based Overley) that performs overlay measurement of lattice marks GM by the scatterometry method. ) Type overlay measuring device is used. In step S518, main controller 50 acquires information relating to the overlay accuracy from inline overlay measuring instrument 800. In parallel with the overlay measurement on the first wafer W, the exposure apparatus 10 performs an exposure operation on the second and subsequent wafers W. Also in the exposure operation of the second and subsequent wafers W, alignment measurement and scatter measurement are performed prior to the exposure operation, and the alignment measurement result is corrected using the correction coefficient.

  Main controller 50 determines in step S520 whether or not the overlay accuracy is within an allowable range based on the information regarding the overlay accuracy acquired in step S518, and if it is within the allowable range, the correction used in step S512. Assuming that the coefficient is appropriate (Yes determination), the subsequent wafer exposure operation is performed. On the other hand, if the overlay accuracy is outside the allowable range (No determination), the process proceeds to step S522, the correction coefficient is corrected, and the subsequent wafer exposure operation is performed. As described above, since the processing from step S512 to S522 is performed in parallel with the exposure operation of the second and subsequent wafers W, the correction value determined in step S522 is the number of sheets in one lot. This is applied to subsequent wafer alignment results. Thereby, the exposure accuracy (yield) of the wafer on which the overlap exposure is performed based on the corrected correction value is improved. Note that the alignment measurement and scatter measurement of the second wafer may be started after the processing up to step S522 is completed for the wafer W at the head of the lot (first wafer). In this case, tact is reduced, but overall yield is improved.

  Here, the overlay measuring instrument 800 (see FIG. 7) is configured to measure the misalignment between lattice marks by the DBO method, so that the shape of the underlying lattice mark GM itself is normal. Regardless of the case where there is an overlap between the lattice marks GM (see FIG. 21A), and there is a defect in the shape of the underlying lattice mark GM even though the lattice marks GM are accurately overlaid. Similarly (see FIG. 21B), the intensity and phase of a pair of diffracted lights (for example, the same number of positive and negative diffracted lights) from the grating mark GM are asymmetric (see FIG. 21A and FIG. 21B). (See the black arrow in FIG. 21 (b)). Since the overlay measuring instrument 800 obtains the amount of overlay deviation based on the intensity and phase of the pair of diffracted lights, similarly to the alignment sensors 32p and 32s, the overlay accuracy is actually ensured (see FIG. 21 (b)), there is a possibility that it is determined that the overlay accuracy is lowered (overlap measuring instrument 800 is deceived). In order to avoid such distortion of the overlay measuring instrument 800, the lower layer (underground) lattice mark GM is measured by the alignment sensors 32p and 32s before the upper layer pattern is exposed, and the shape of each lattice mark is measured (actually). It is preferable to transmit the measurement result (estimation result) to the optical overlap measuring instrument 800 in advance.

  As described above, the alignment system 30 of the exposure apparatus 10 of the present embodiment calculates the scatter measurement value for each lattice mark GM based on the diffracted light from the lattice mark GM simultaneously with the position measurement of each lattice mark GM. Can be acquired. Therefore, a decrease in throughput can be suppressed as compared with the case where the position information of the lattice mark and the scatter measurement value are individually measured.

  In addition, since the exposure apparatus 10 of the present embodiment corrects the alignment result by correcting the correction coefficient using the scatter measurement value, the exposure accuracy can be improved. Further, since the measurement value of the optical overlay measuring instrument 800 can be corrected using the scatter measurement value, the overlay measurement accuracy of each pattern is also improved.

  Moreover, in the said embodiment, although the stage apparatus 20 had the wafer stage 24 and the measurement stage 26, the structure of the stage apparatus 20 is not limited to this, It can change suitably. That is, like the stage apparatus 120 shown in FIG. 22, two wafer stages 124 that can hold the wafer W may be provided. In the stage apparatus 120, the wafer loading and unloading operations can be performed on the other wafer stage 124 in parallel with the alignment measurement operation and the scanning exposure operation on the wafer W held on the one wafer stage 124. . In this case, at least one of the pair of wafer stages 124 has the FD bar 28 on which a plurality of reference marks are formed (in FIG. 22, each of the pair of wafer stages 124 has the FD bar 28). Baseline measurement (calibration operation) of the alignment system 30 is performed using the FD bar 28.

  The exposure apparatus 10 may not include the alignment system 30. In this case, a measurement apparatus including the alignment system 30 may be prepared separately from the exposure apparatus 10. The substrate on which the measurement apparatus performs the alignment operation may be transported to the exposure apparatus 10 using a transport apparatus. The exposure apparatus 10 may calculate the correction amount of the position coordinates of the plurality of shot areas using the mark detection information acquired by the measurement apparatus, and then expose the substrate. Alternatively, the exposure apparatus 10 may include the alignment system 30 even when a measuring apparatus including the alignment system 30 exists. In this case, the exposure apparatus 10 may further perform an alignment operation using the result of the alignment operation performed by the measurement apparatus. An exposure system provided with such an exposure apparatus and an alignment system separate from the exposure apparatus is disclosed in, for example, US Pat. No. 4,861,162.

The illumination light IL is not limited to ArF excimer laser light (wavelength 193 nm), but may be ultraviolet light such as KrF excimer laser light (wavelength 248 nm) or vacuum ultraviolet light such as F ₂ laser light (wavelength 157 nm). good. As disclosed in US Pat. No. 7,023,610, single-wavelength laser light in the infrared region or visible region oscillated from a DFB semiconductor laser or fiber laser as vacuum ultraviolet light is erbium (or A harmonic which is amplified by a fiber amplifier doped with both erbium and ytterbium and wavelength-converted into ultraviolet light using a nonlinear optical crystal may be used. Further, the wavelength of the illumination light IL is not limited to light of 100 nm or more, and light having a wavelength of less than 100 nm may be used, and EUV (Extreme Ultraviolet) light in the soft X-ray region (5 to 15 nm wavelength region) is used. The above embodiment can also be applied to an exposure apparatus. In addition, the above embodiment can be applied to an exposure apparatus that uses charged particle beams such as an electron beam or an ion beam.

  In addition, the projection optical system in the exposure apparatus may be not only a reduction system but also an equal magnification and an enlargement system, and the projection optical system may be not only a refraction system but also a reflection system or a catadioptric system. The image may be an inverted image or an erect image.

  In the above embodiment, a light transmissive mask (reticle) in which a predetermined light shielding pattern (or phase pattern / dimming pattern) is formed on a light transmissive substrate is used. As disclosed in, for example, Japanese Patent No. 6,778,257, an electronic mask (variable shaping mask, active pattern) that forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed. It is also possible to use a mask or an image generator (including a DMD (Digital Micro-mirror Device) which is a kind of non-light emitting image display element (spatial light modulator)).

  In the above-described embodiment, a so-called immersion exposure apparatus that performs an exposure operation in a state where a liquid (pure water) is filled between the projection optical system and an exposure target object (wafer) has been described. Absent.

  Further, as disclosed in International Publication No. 2001/035168, etc., an exposure apparatus (lithography system) that forms a line and space pattern on a wafer W by forming interference fringes on the wafer W. The above embodiment can also be applied. The above-described embodiment can also be applied to a step-and-stitch reduction projection exposure apparatus that synthesizes a shot area and a shot area.

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

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

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

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

  As described above, the mark detection apparatus and the mark detection method of the present invention are suitable for detecting a mark provided on an object. The exposure apparatus of the present invention is suitable for forming a predetermined pattern on an object. The device manufacturing method of the present invention is suitable for manufacturing micro devices.

  DESCRIPTION OF SYMBOLS 10 ... Exposure apparatus, 20 ... Stage apparatus, 30 ... Alignment system, 32p ... Primary alignment sensor, 32s ... Secondary alignment sensor, GM ... Grid mark, W ... Wafer.

Claims (31)

A plurality of detection devices that are arranged at predetermined intervals in a first direction within a predetermined two-dimensional plane and that detect marks provided on the object via an optical system; A mark detection system for simultaneously detecting a plurality of provided marks;
Each optical of each of the plurality of detection devices based at least on information on the depth of focus of the optical system of each of the plurality of detection devices and information on the position of the object in a second direction orthogonal to the two-dimensional plane. And a control system for controlling a positional relationship between the system and the object.   The mark detection apparatus according to claim 1, wherein the control system controls the positional relationship such that each of a plurality of detection target marks is positioned within the focal depth of the respective optical system.   The mark detection apparatus according to claim 2, wherein the control system detects a position of each of the plurality of detection target marks.   The mark detection apparatus according to claim 3, wherein the control system corrects an error in mark position detection caused by the telecentricity of the optical system of each of the plurality of detection apparatuses.   The mark detection apparatus according to claim 4, further comprising a telecentric measurement unit that measures the telecentricity of the optical system of each of the plurality of detection apparatuses.   6. The mark detection device according to claim 4, wherein the error is corrected by using a deviation amount between a focal point of the optical system of each of the plurality of detection devices and the object in the second direction. 7.   The mark detection apparatus according to claim 6, further comprising an alignment focus detection unit that measures an amount of deviation between the focal point of the optical system of each of the plurality of detection apparatuses and the object in the second direction. The mark includes a diffraction grating,
The mark detection system irradiates the diffraction grating with a measurement beam, and moves the mark and the measurement beam relative to each other, and based on the interference of a pair of diffracted lights of the same order from the diffraction grating of the measurement beam. The mark detection apparatus according to any one of claims 1 to 7, which detects a mark.   The mark detection apparatus according to claim 1, wherein the control system obtains a position of the object in a second direction orthogonal to the two-dimensional plane and an inclination amount of the object with respect to the two-dimensional plane. .   The control system performs position measurement of the detection positions of the plurality of detection devices on the object in the second direction, generates a primary approximation formula based on the result of the position measurement, and the primary approximation formula The mark detection apparatus according to claim 9, wherein an inclination amount of the object is obtained based on an inclination of the object.   The control system generates a graph based on the first-order approximation expression on a coordinate system having the first direction as a horizontal axis and the second direction as a vertical axis, and plots the position measurement result on the graph. A position in the second direction of the graph is set so as to pass through an intermediate point between a point farthest in the plus direction and a point farthest in the minus direction with respect to the second direction with respect to the graph. The mark detection apparatus according to claim 10, wherein a position of the object in the second direction is set based on an axial position. The mark detection device according to any one of claims 1 to 11,
A positioning device for positioning the object according to the position calculated by the control system of the mark detection device;
An exposure apparatus comprising: a pattern forming apparatus that forms a predetermined pattern by exposing the object positioned by the positioning apparatus with an energy beam. Exposing the object using the exposure apparatus of claim 12;
Developing the exposed object. Simultaneously detecting a plurality of marks provided on an object using a mark detection system including a plurality of detection devices arranged at predetermined intervals in a first direction within a predetermined two-dimensional plane;
Each optical system of each of the plurality of detection devices based at least on information on the depth of focus of the optical system of each of the plurality of detection devices and information on the position of the object in a second direction orthogonal to the two-dimensional plane. And detecting a positional relationship between the object and the object.   The mark detection method according to claim 14, wherein in the control, each of a plurality of detection target marks is positioned within the focal depth of the respective optical system.   The mark detection method according to claim 14, further comprising detecting a position of each of the plurality of detection target marks.   The mark detection method according to any one of claims 14 to 16, further comprising calculating a position of the object in the second direction when a mark to be detected is located.   The mark detection method according to claim 17, wherein in the calculation, the position of the object in a second direction orthogonal to the two-dimensional plane and the amount of inclination of the object with respect to the two-dimensional plane are obtained.   In the calculation, the position of the detection position of each of the plurality of detection devices on the object is measured in the second direction, and a primary approximation formula is generated based on the result of the position measurement. The mark detection method according to claim 18, wherein an inclination amount of the object is obtained based on an inclination of an expression.   In the calculation, a graph based on the first-order approximation expression is generated on a coordinate system having the first direction as the horizontal axis and the second direction as the vertical axis, and the position measurement result is plotted on the graph. , Setting a position in the second direction of the graph so as to pass through an intermediate point between a point farthest in the positive direction and a point farthest in the negative direction with respect to the second direction with respect to the graph, The mark detection method according to claim 19, wherein the position of the object in the second direction is set based on a position in the vertical axis direction.   In the detection, the diffraction grating of the mark is irradiated with a measurement beam, and the mark and the measurement beam are moved relative to each other, while the measurement beam interferes with a pair of diffracted lights of the same order from the diffraction grating. The mark detection method according to any one of claims 14 to 20, wherein the mark is detected based on the mark. A device manufacturing method for forming a plurality of patterns on an object,
Measuring the position of the first mark provided on the object using a measuring device that irradiates the mark including the diffraction grating with measurement light, and performing asymmetric measurement related to the asymmetry of the first mark;
Correcting the position measurement result of the first mark using a correction coefficient corresponding to the asymmetric measurement result;
Forming a pattern overlapping the existing pattern on the object based on the position measurement result of the first mark after the correction, and forming a second mark overlapping the first mark;
Measuring the overlay accuracy of the patterns using the first and second marks;
Correcting the correction coefficient when the overlay accuracy measurement result does not satisfy a predetermined condition, and
The measurement apparatus includes an optical member for generating reference light that interferes with diffracted light from the mark of the measurement light, and the position measurement and the asymmetry are performed based on interference between the diffracted light and the reference light. Device manufacturing method for measuring.   23. The device manufacturing method according to claim 22, wherein the optical member includes a diffraction grating that generates diffracted light or confusion light as the reference light.   24. The device manufacturing method according to claim 22 or 23, wherein the measurement apparatus makes the measurement light incident obliquely on the object surface.   The device manufacturing method according to any one of claims 22 to 24, wherein the asymmetric measurement related to the first mark is performed simultaneously with the position measurement of the first mark.   26. The device manufacturing method according to any one of claims 22 to 25, wherein the overlap measurement using the first and second marks is performed using a scanning line electron microscope. A device manufacturing system for forming a plurality of patterns on an object,
A measurement system that performs measurement of the position of the first mark provided on the object using a measurement device that irradiates the mark including the diffraction grating with measurement light, and performs asymmetric measurement related to the asymmetry of the first mark;
A control system for correcting the position measurement result of the first mark using a correction coefficient according to the asymmetric measurement result;
A pattern forming system for forming a pattern by overlapping the existing pattern on the object based on the position measurement result of the first mark after the correction, and by forming a second mark on the first mark,
An overlay measurement system that measures the overlay accuracy between the patterns using the first and second marks,
The control system corrects the correction coefficient when the overlay accuracy measurement result does not satisfy a predetermined condition,
The measurement apparatus includes an optical member for generating reference light that interferes with diffracted light from the mark of the measurement light, and the position measurement and the asymmetry are performed based on interference between the diffracted light and the reference light. A device manufacturing system that performs measurements.   28. The device manufacturing system according to claim 27, wherein the optical member includes a diffraction grating that generates diffracted light or scattered light as the reference light.   29. The device manufacturing system according to claim 27 or 28, wherein the measurement apparatus makes the measurement light incident obliquely on the object surface.   30. The device manufacturing system according to claim 27, wherein the measurement system simultaneously performs position measurement of the first mark and the asymmetric measurement related to the first mark.   30. The device manufacturing system according to any one of claims 27 to 29, wherein the overlay measurement system includes a scanning line electron microscope.

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