JP2009252850A - Mobile body system, exposure apparatus and exposure method, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve highly precise position measurement and driving control with respect to a wafer table. <P>SOLUTION: Measurement light beams Lx1, Ly1<SB>1</SB>, and Ly1<SB>2</SB>are made incident on a grating provided on an upper surface of the table WTB through one side face thereof from light sources 16Xa, 16Ya<SB>1</SB>, and 16Ya<SB>2</SB>constituting an encoder system, and optical detectors 16Xb, 16Yb<SB>1</SB>and 16Yb<SB>2</SB>receive diffracted light beams Lx2, Ly2<SB>1</SB>, and Ly2<SB>2</SB>originating from those measurement light beams to measure X, Y and θz position information on the table WTB. Consequently, an influence of fluctuations of a peripheral atmosphere of the table WTB is small, so the position of the table WTB is measured with high precision. Further, the table WTB is driven based upon the position information on the table WTB obtained using the encoder system. Therefore, the table WTB is driven with high precision. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a moving body system, an exposure apparatus and an exposure method, and a device manufacturing method. More specifically, the present invention relates to a moving body system including a moving body that moves while holding an object, an exposure apparatus including the moving body system, and energy. The present invention relates to an exposure method for irradiating an object with a beam to form a predetermined pattern on the object, and a device manufacturing method using the exposure apparatus or the exposure method.

  Conventionally, in a lithography process for manufacturing microdevices (electronic devices and the like) such as semiconductor elements and liquid crystal display elements, a step-and-repeat projection exposure apparatus (so-called stepper) or a step-and-scan projection exposure apparatus ( A so-called scanning stepper (also called a scanner)) is used relatively frequently.

  In this type of exposure apparatus, a wafer stage that holds a wafer in order to transfer a reticle (or mask) pattern to a plurality of shot areas on an object to be exposed (hereinafter referred to as a wafer) such as a wafer or a glass plate. Is driven in the XY two-dimensional direction by, for example, a linear motor. The position measurement of the wafer stage is generally performed using a high-resolution laser interferometer with good measurement stability over a long period of time.

  However, due to the miniaturization of patterns due to the high integration of semiconductor elements, more accurate position control of the stage is required, and now the temperature change and / or temperature of the atmosphere on the beam path of the laser interferometer Short-term fluctuations in measured values due to air fluctuations that occur due to the influence of gradients occupy a large weight in the overlay budget.

  On the other hand, there is an encoder as a measuring device other than the laser interferometer used for measuring the position of the stage. However, since the encoder uses a scale (grating, etc.) in the measurement, the grating pitch drift, fixed position drift, or thermal Lack of mechanical long-term stability of the scale due to expansion or the like. For this reason, the encoder has the disadvantage that it lacks the linearity of the measured value and is inferior in long-term stability compared to the laser interferometer.

  In view of the drawbacks of the laser interferometer and the encoder described above, various apparatuses for measuring the position of the stage using both the laser interferometer and the encoder (position detection sensor using a diffraction grating) have been proposed (for example, (See Patent Documents 1 and 2). In particular, recently, an encoder having a measurement resolution equal to or higher than that of a laser interferometer has emerged (for example, see Patent Document 3), and a technique for combining the above-described laser interferometer and encoder is attracting attention. It has become.

  However, when the scale of the interferometer or encoder (grating, etc.) is provided on the outer surface of the stage, such as the side surface, the position on the stage (on the stage) (The positional relationship with the predetermined point) changes, and this is likely to reduce the position measurement accuracy of the stage. In addition, for example, from the viewpoint of improving throughput, even if a new technique is proposed in which exposure is started during the acceleration of the wafer stage in the scanning stepper, even if the stage on the mirror or scale accompanying the acceleration of the above stage is proposed. The change in position may be an obstacle for the implementation of the new technology.

US Pat. No. 6,819,425 JP 2004-101362 A US Pat. No. 7,238,931

  The present invention has been made under the circumstances described above. From a first viewpoint, the present invention can hold an object and move substantially along a predetermined plane, and can be moved to the predetermined plane on the back side of the object. A moving body in which a grating is disposed along a substantially parallel plane, and light having a predetermined wavelength can travel inside; from the outside of the moving body through one side surface of the moving body intersecting the predetermined plane; The gratings derived from the first and second measurement lights are respectively incident on the first and second measurement points at different positions with respect to a direction orthogonal to the measurement direction within the predetermined plane of the grating. A measurement system that receives diffracted light from the movable body and measures position information regarding the measurement direction and the rotation direction of the movable body in the predetermined plane; and a drive system that drives the movable body based on the positional information of the movable body ; It is a mobile system comprising a.

  According to this, in the measurement of the position information of the moving body, the diffracted light is not affected by the fluctuation of the ambient atmosphere of the moving body on the optical path through which the moving body passes. Furthermore, since the optical path of the diffracted light is close to the outside of the moving body and propagates in almost the same atmosphere, the influence of fluctuations in the surrounding atmosphere is small. Therefore, position information regarding the measurement direction and the rotation direction within a predetermined plane of the moving body can be measured with high accuracy. Further, the drive system drives the moving body based on the position information of the moving body. Therefore, highly accurate drive control of the moving body is possible.

  According to a second aspect of the present invention, there is provided an exposure apparatus for forming a pattern on an object by irradiation with an energy beam, the patterning apparatus for irradiating the object with the energy beam; and the object irradiated with the energy beam. An exposure apparatus comprising: the moving body system of the present invention held by the moving body.

  According to this, it is possible to form a pattern on the object with high accuracy by the patterning device.

  According to a third aspect of the present invention, there is provided a device manufacturing method comprising: exposing a substrate using the exposure apparatus of the present invention; and developing the exposed substrate. is there.

  According to a fourth aspect of the present invention, there is provided an exposure method for irradiating an object with an energy beam to form a predetermined pattern on the object, the object being held, and the predetermined surface on the back side of the object. A grating is arranged along a plane substantially parallel to the plane, and a movable body in which light of a predetermined wavelength can travel is moved along the predetermined plane, and one of the movable bodies crossing the predetermined plane. First and second measurement lights are incident on the first and second measurement points at different positions with respect to the direction orthogonal to the measurement direction within the predetermined plane of the grating from the outside of the movable body via side surfaces, 1. receiving diffracted light from the grating derived from the second measurement light and measuring positional information on the measurement direction and the rotation direction of the movable body in the predetermined plane; Is an exposure method comprising: based on the information, a step of driving the movable body.

  According to this, on the optical path through which the diffracted light passes through the moving body, it is not affected by the fluctuation of the ambient atmosphere of the moving body. Furthermore, since the optical path of the diffracted light is close to the outside of the moving body and propagates in almost the same atmosphere, the influence of fluctuations in the surrounding atmosphere is small. Therefore, position information regarding the measurement direction and the rotation direction within a predetermined plane of the moving body can be measured with high accuracy. Further, in the driving step, the moving body is driven based on the position information of the moving body. Therefore, highly accurate drive control of the moving body is possible.

  From a fifth aspect, the present invention is a device manufacturing method comprising: exposing a substrate as the object using the exposure method of the present invention; and developing the exposed substrate.

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

  FIG. 1 shows a schematic configuration of an exposure apparatus 100 according to an embodiment. The exposure apparatus 100 is a step-and-scan reduction projection exposure apparatus. Exposure apparatus 100 includes a light source and an illumination optical system. Illumination system 12 illuminates reticle R with illumination light IL, reticle stage RST that holds reticle R, projection optical system PL, wafer stage WST that holds wafer W, and A main controller 20 (not shown in FIG. 1, refer to FIG. 4) and the like are provided for overall control of the entire apparatus. In the following, the direction parallel to the optical axis AX of the projection optical system PL is the Z-axis direction, and the direction in which the reticle R and the wafer W are relatively scanned in a plane perpendicular to the optical axis AX is the Y-axis direction, Z-axis and Y-axis. The direction orthogonal to the X axis direction is the X axis direction, and the rotation (tilt) directions around the X axis, the Y axis, and the Z axis are the θx, θy, and θz directions, respectively.

  The illumination system 12 illuminates a slit-shaped illumination region extending in the X-axis direction on the reticle R defined by a reticle blind (not shown) with illumination light IL with a substantially uniform illuminance. Here, as the illumination light IL, for example, ArF excimer laser light (wavelength 193 nm) is used.

  On reticle stage RST, reticle R on which a circuit pattern or the like is drawn is fixed, for example, by vacuum suction. Reticle stage RST coincides with the optical axis of illumination system 12 (to be described later, optical axis AX of projection optical system PL) by reticle stage drive system 13 (not shown in FIG. 1, see FIG. 4) for position control of reticle R. 1), and can be driven at a predetermined scanning speed in a predetermined scanning direction (left-right direction in FIG. 1, ie, the Y-axis direction).

  The position of the reticle stage RST in the XY plane is, for example, 0.5 to 1 nm by a reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 11 via the side surface (mirror-finished end surface) of the reticle stage RST. It is always detected with a resolution of the order. Position information of reticle stage RST from reticle interferometer 11 is sent to main controller 20 (see FIG. 4). Main controller 20 drives reticle stage RST via reticle stage drive system 13 based on position information of reticle stage RST.

  As the projection optical system PL, for example, a refractive optical system including a plurality of lenses (lens elements) arranged along an optical axis AX parallel to the Z-axis direction is used. The projection optical system PL is, for example, both-side telecentric and has a predetermined projection magnification (for example, 1/4 times or 1/5 times). For this reason, when the illumination area is illuminated by the illumination light IL from the illumination system 12, the illumination light that has passed through the reticle R arranged so that the first surface (object surface) and the pattern surface of the projection optical system PL substantially coincide with each other. A surface on which a reduced image of the circuit pattern of the reticle R in the illumination area (a reduced image of a part of the circuit pattern) is disposed on the second surface (image surface side) by the IL through the projection optical system PL. Is formed in an area (exposure area IA) conjugate to the illumination area on the wafer W coated with a resist (sensitive agent). Then, by synchronous driving of reticle stage RST and wafer stage WST, reticle R is moved relative to the illumination area (illumination light IL) in the scanning direction (Y-axis direction) and at the same time with respect to exposure area IA (illumination light IL). By moving the wafer W relative to the scanning direction (Y-axis direction), scanning exposure of one shot area (partition area) on the wafer W is performed, and a reticle pattern is formed in the shot area. That is, in this embodiment, a pattern is generated on the wafer W by the illumination system 12, the reticle R, and the projection optical system PL, and the sensitive layer (resist layer) on the wafer W is exposed on the wafer W by the illumination light IL. A pattern is formed.

  Wafer stage WST attracts and holds wafer holder WH on its upper surface by an electrostatic chuck mechanism (not shown). Further, the wafer holder WH attracts and holds the wafer W by an electrostatic chuck mechanism included in the wafer holder WH. As shown in FIG. 1, wafer stage WST includes a stage main body 14, a wafer table WTB fixed thereon, and a wafer holder WH detachably attached to wafer table WTB by an electrostatic chuck mechanism (not shown). , Including. The holding mechanism for fixing the wafer holder WH to the wafer table WTB is not limited to the electrostatic chuck mechanism, and may be a vacuum chuck mechanism or a clamp mechanism, for example. Wafer holder WH may be formed integrally with wafer table WTB, or may hold wafer W by a mechanism different from the electrostatic chuck mechanism, such as a vacuum chuck mechanism.

  The stage main body 14 (wafer stage WST) is, for example, driven by a stage drive system 27 (see FIG. 4) including a linear motor, a voice coil motor (VCM), and the like, in the X-axis direction, Y-axis direction, Z-axis direction, θx direction, θy And 6 degrees of freedom in the θz direction. Thereby, the wafer W can move in the direction of six degrees of freedom. The stage main body 14 may be driven in the X-axis direction, the Y-axis direction, and the θz direction, and the wafer table WTB may be finely moved at least in the Z-axis direction, the θx direction, and the θy direction. In this case, wafer table WTB may be finely movable in the direction of six degrees of freedom.

  Wafer table WTB is a substantially square plate-like member that is made of a transparent member (for example, glass or the like) in plan view (viewed from above). Wafer holder WH is held at the center of the upper surface of wafer table WTB. Wafer table WTB is composed of a transparent member transparent to at least this measurement light because measurement light of an encoder system, which will be described later, travels inside. Wafer table WTB includes a first surface (upper surface) and a second surface (lower surface) substantially parallel to the XY plane, a pair of side surfaces extending in the X-axis direction, and a pair of side surfaces extending in the Y-axis direction, respectively. Have In this embodiment, as will be described later, laser light for measurement (measurement light) is incident on the inside of wafer table WTB or emitted to the outside from four side surfaces (hereinafter also referred to as end surfaces). The transparent member is preferably a material having a low coefficient of thermal expansion, and synthetic quartz or the like is used as an example in this embodiment. Wafer table WTB may be entirely formed of a transparent member, but only a part of wafer table WTB through which measurement laser light passes may be formed of a transparent member.

  As shown in FIG. 3A, the −Y side end surface and the + Y side end surface of wafer table WTB extend in the X-axis direction and have a predetermined angle (θ (0 ° <θ <90 °) with respect to the XZ plane. ) Inclined. That is, both end faces form an acute angle (90 ° −θ) with respect to the upper surface of wafer table WTB. Similarly, the −X side end surface and the + X side end surface of wafer table WTB extend in the Y-axis direction and are inclined at a predetermined angle (θ) with respect to the YZ plane.

  At the center of the upper surface of wafer table WTB (a portion slightly larger than wafer holder WH), as shown in FIG. 1, a grating having a periodic direction in the X-axis direction, a grating having a periodic direction in the Y-axis direction, A two-dimensional grating (hereinafter simply referred to as a “grating”) 24 in combination is installed horizontally. The upper surface of the grating 24 is covered with a cover glass 51 as a protective member. In the present embodiment, the above-described electrostatic chuck mechanism for attracting and holding the wafer holder WH is provided on the upper surface of the cover glass 51. In this embodiment, the cover glass 51 is provided so as to cover almost the entire upper surface of the wafer table WTB. However, the cover glass 51 may be provided so as to cover only a part of the upper surface including the grating 24. In this embodiment, the cover glass 51 is made of the same material as that of the wafer table WTB. However, the cover glass 51 may be made of another material such as metal, ceramics, or a thin film.

  Wafer table WTB may include cover glass 51. In this case, the surface on which grating 24 is formed is arranged not in the uppermost surface of wafer table WTB but in the interior thereof. Further, the grating 24 may be provided on the back surface of the wafer holder. Further, instead of providing a protective member such as a cover glass, a wafer holder or the like may be used instead.

  Position information of wafer stage WST in the XY plane, that is, in the X, Y, and θz directions, is always detected using a grating 24 by an encoder system described later. The detected position information of wafer stage WST is sent to main controller 20. Main controller 20 controls the position of wafer stage WST by driving the linear motor and voice coil motor described above based on this position information.

  Further, in the exposure apparatus 100, independent of the encoder system described above, all six degrees of freedom (X, Y, Z, θx) of the wafer table WTB (wafer W) are provided via the movable mirror 17 fixed to the wafer table WTB. , Θy, θz) is provided with a laser interferometer system 18 for measuring positional information. The laser interferometer system 18 includes a reflection surface (not shown) inclined by 45 degrees with respect to the XY plane fixed to the wafer table WTB, and a reflection surface fixed to a main frame (not shown) that holds the projection optical system PL. The Z position of the wafer table WTB can be measured via the.

  FIG. 4 is a block diagram showing the configuration of the control system of the exposure apparatus 100. This control system is configured around the main controller 20. The main controller 20 includes a workstation (or a microcomputer) and the like, and comprehensively controls each part of the exposure apparatus 100 such as the detection system.

Next, the configuration of encoder system 16 (see FIG. 4) used for position measurement of wafer stage WST will be described. Encoder system 16 of the present embodiment, the grating 24 described above, the laser beam for measuring the grating 24 (measurement light) _Lx1, Ly1 _1, Ly1 light source ₂ irradiates each _16Xa, 16Ya _1, 16Ya ₂ (light source 16Ya ₁ , 16Ya ₂ receive a plurality of diffracted beams Lx2, Ly2 ₁ and Ly2 ₂ from the grating 24, respectively (not shown in FIGS. 1 and 3A to 3C, see FIG. 2A). The photodetectors 16Xb, 16Yb ₁ , 16Yb ₂ (the photodetectors 16Yb ₁ , 16Yb ₂ are not shown in FIGS. 1 and 3A to 3C, see FIG. 2A). I have. The photodetectors 16Xb, 16Yb ₁ , 16Yb ₂ respectively collect a plurality of diffracted lights Lx2, Ly2 ₁ , Ly2 ₂ to generate interference light, and receive the generated interference light. A light receiving element such as a CCD.

2A is a perspective view showing the positional relationship between the exposure area IA, the light sources 16Xa, 16Ya ₁ and 16Ya ₂ and the photodetectors 16Xb, 16Yb ₁ and 16Yb ₂ . The light source 16Xa and the light detector 16Xb are arranged at substantially equal intervals from the center of the exposure area IA to the −Y side and the + Y side. The light sources 16Ya ₁ and 16Ya ₂ and the photodetectors 16Yb ₁ and 16Yb ₂ are arranged at positions that are substantially equidistant from the center of the exposure area IA on the + X side and the −X side. In the present embodiment, the center of the exposure area IA coincides with the optical axis AX of the projection optical system PL in the XY plane.

  By using the grating 24, the light source 16Xa, and the light receiving system 16Xb, position information regarding the X-axis direction of the wafer table WTB (wafer W) can be detected. An encoder configured to include these elements is referred to as an X encoder 16X. As shown in FIGS. 2A and 3A, the light source 16Xa causes the measurement light Lx1 to be parallel to the Y axis in the XY plane and in a direction that forms an angle θ with respect to the Y axis in the YZ plane. Eject. Measurement light Lx1 is perpendicularly incident on the −Y side end surface of wafer table WTB, and enters wafer table WTB. The entering measurement light Lx1 propagates inside the wafer table WTB and enters the grating 24 at an incident angle (90 ° −θ) in the YZ plane. Here, as shown in FIG. 2B, the installation position of the light source 16Xa is such that the irradiation point of the measurement light Lx1 on the grating 24 is always located at a point IAa immediately below the center of the exposure area IA. The emission angle of the measurement light Lx1 and the inclination angle θ of the end surface of the wafer table WTB are determined.

  The measurement light Lx1 enters the grating 24 and is reflected and diffracted by the grating having the X-axis direction as a periodic direction, thereby generating a plurality of diffracted lights. 2A and 2B show ± first-order diffracted light Lx2. These ± 1st-order diffracted lights Lx2 form an emission angle (90 ° −θ) in the YZ plane from the grating 24 as shown in FIG. 3A and are shown in FIG. 2B. In the XY plane, the light beams are emitted from the central axis parallel to the Y axis in directions that form diffraction angles having the same absolute value (but different signs). Note that these diffracted lights overlap in the direction perpendicular to the paper surface in FIGS. 3 (A) to 3 (C).

  The diffracted light Lx2 is emitted to the outside from the + Y side end surface of the wafer table WTB, and is received by the photodetector 16Xb. The photodetector 16Xb collects and synthesizes the diffracted light Lx2 using a diffraction grating provided therein, generates interference light, and detects its intensity. The detection result is sent to the main controller 20. Main controller 20 calculates position information regarding the X-axis direction of wafer table WTB (wafer W) from the received detection result. Here, as can be seen from FIG. 2B, the optical path of the measurement light Lx1 of the X encoder 16X is orthogonal to the measurement direction (X-axis direction) when viewed from the Z-axis direction (in the XY plane). .

Similarly, by using the grating 24 and the light source 16Ya ₁ and light receiving system 16Yb _1, it is possible to detect the positional information about the Y-axis direction of the surface position of wafer table WTB (wafer W). An encoder configured to include these elements, referred to as a Y encoder 16Y _1. As shown in FIG. 2A, the light source 16Ya ₁ emits the measurement light Ly1 ₁ in a direction that forms an angle θ parallel to the X axis in the XY plane and in the XZ plane with respect to the X axis. Measuring light LyI ₁ is incident perpendicularly on the end face on the + X side of wafer table WTB, enters the inside of wafer table WTB. The entering measurement light Ly11 ₁ propagates through the wafer table WTB and enters the grating 24 at an incident angle (90 ° −θ) in the XZ plane. Here, as shown in FIG. 2 (B), the irradiation point on the grating 24 of the measuring light LyI ₁ is always located on the + X side and the -Y side of the point IAa right under the center of exposure area IA as such, the installation position of the light source 16Ya _1, exit angle of the measuring light LyI _1, and the inclination angle of the end surface of wafer table WTB theta, is defined.

Measuring light LyI ₁ is incident on the grating 24, by being reflected and diffracted by the grating to the Y-axis direction and periodic direction, a plurality of diffracted light is generated. FIG. 2 (A) and FIG. 2 (B), the diffracted light Ly2 ₁ of ± 1-order is shown. These ± 1st-order diffracted lights Ly2 ₁ form an emission angle (90 ° −θ) in the XZ plane from the grating 24, and as shown in FIG. 2B, the X-axis in the XY plane Are emitted in directions of diffraction angles having the same absolute value (but with different signs) from the central axis parallel to.

Diffracted light Ly2 ₁ is emitted to the outside from the −X side end face of wafer table WTB, and is received by photodetector 16Yb ₁ . The photodetector 16Yb ₁ collects and synthesizes the diffracted light Ly2 ₁ using a diffraction grating provided therein, generates interference light, and detects its intensity. The detection result is sent to the main controller 20.

Like the Y encoder 16Y ₁ described above, by using a Y encoder 16Y ₂ comprising a grating 24 and the light source 16Ya ₂ and the light receiving system 16Yb _2, to detect the position information about the Y-axis direction of the surface position of wafer table WTB (wafer W) be able to. As shown in FIG. 2 (A), the light source 16Ya ₂ are parallel, and emits a measurement light LyI ₂ and the measurement light LyI _1. Measuring light LyI ₂ enters the internal table through the end surface on the + X side of wafer table WTB, incident on the grating 24. Here, as shown in FIG. 2 (B), the irradiation point on the grating 24 of the measurement light LyI ₂ is always located on the -X side and + Y side IAa point directly below the center of exposure area IA as such, the installation position of the light source 16Ya _2, the exit angle of the measuring light LyI _2, and the inclination angle of the end surface of wafer table WTB theta, is defined.

Incidentally, as shown in FIG. 2 (B), in the XY plane, the measuring light _LyI 1, LyI ₂ is about an axis parallel to the X axis passing through the point IAa, respectively -Y side, + Y side at equal Distanced apart. Thus, the measuring light _LyI 1, LyI ₂ irradiation point on grating 24, -Y side from each point IAa, are equidistantly spaced on the + Y side. Further, as will be described later, in order to measure the yawing amount (rotation in the θz direction) of the wafer table WTB, the wafer table WTB is spaced equidistant from the point IAa to the + X side and the −X side.

Measuring light LyI ₂ is incident on the grating 24, by being reflected and diffracted by the grating to the Y-axis direction and periodic direction, a plurality of diffracted light is generated. FIG. 2 (A) and FIG. 2 (B), ± 1-order diffracted light Ly2 ₂ is shown. These ± 1st-order diffracted lights Ly2 ₂ are emitted to the outside from the −X side end surface of wafer table WTB along optical paths parallel to the optical paths of ± 1st-order diffracted lights Ly2 ₁ , respectively, and are detected by photodetector 16Yb _2. Is received by. The photodetector 16Yb ₂ collects and combines the diffracted light Ly22 ₂ using a diffraction grating provided therein, generates interference light, and detects its intensity. The detection result is sent to the main controller 20 (not shown).

Main controller 20 calculates position information regarding wafer table WTB (wafer W) in the Y-axis direction and the θz direction based on the detection results received from photodetectors 16Yb ₁ and 16Yb ₂ . Note that the optical paths of the measurement lights Ly1 ₁ and Ly1 ₂ of the Y encoders 16Y ₁ and 16Y ₂ are seen in the Z-axis direction (in the XY plane) (Y-axis), as can be seen from FIG. Direction).

As shown in FIG. 3A to FIG. 3C, the measurement light Lx1 emitted from the light source 16Xa is always on the wafer table WTB at least in the region where the exposure region IA exists on the wafer W. Incident on the Y side end face. Therefore, when wafer table WTB moves within the area shown in FIGS. 3A to 3C, position information regarding the X-axis direction of wafer table WTB is measured using X encoder 16X. Can do. Similarly, the light source 16Ya _1, measuring light _LyI 1 emitted from 16Ya _2, Ly1 _2, in the region at least of the wafer W on the exposure area IA is present, always incident on the end surface on the + X side of wafer table WTB . Therefore, when wafer table WTB moves in the movement area during exposure, it is possible to measure position information regarding wafer table WTB in the Y-axis direction and θz direction using Y encoders 16Y ₁ and 16Y ₂ .

As described above in detail, the encoder system 16 in the present embodiment is such that the measurement light Lx1 emitted from the light source 16Xa is located directly below the exposure area IA via the one side surface from the outside of the wafer table WTB. The grating 24 is irradiated with IAa. Similarly, the light source 16Ya _1, measuring light _LyI 1 emitted from 16Ya _2, Ly1 _2, from each point IAa + X side, is irradiated to the grating 24 spaced equidistantly on the -X side. Thereby, a plurality of diffracted lights are generated. Then, by receiving the diffracted lights Lx2, Ly2 ₁ and Ly2 ₂ derived from the measurement lights Lx1, Ly1 ₁ and Ly1 ₂ using the photodetectors 16Xb, 16Yb ₁ and 16Yb ₂ , respectively, the X axis and the Y axis And position information of the wafer table WTB in the θz direction can be measured. Therefore, in measuring the position information of wafer table WTB, the diffracted light is not affected by fluctuations in the ambient atmosphere of wafer table WTB on the optical path through which wafer table WTB passes. Furthermore, since the optical path of the diffracted light is close to the outside of wafer table WTB and propagates in substantially the same atmosphere, the influence of fluctuations in the surrounding atmosphere is small. Therefore, it becomes possible to measure the position of the wafer table WTB with high accuracy.

  Further, in the present embodiment, main controller 20 drives wafer table WTB (wafer stage WST) based on position information of wafer table WTB by the encoder system. Therefore, wafer table WTB (wafer stage WST) can be driven with high accuracy.

  Further, in the present embodiment, the encoder system 16 capable of measuring the position of the wafer table WTB and the wafer W held by the wafer table WTB with high accuracy is provided, so that the reticle stage RST ( By relatively moving reticle R) and wafer stage WST (wafer W) at a speed ratio corresponding to the projection magnification of projection optical system PL, the pattern of reticle R can be formed on wafer W with high accuracy. Become.

  In the present embodiment, since the grating 24 is provided on the back surface portion of the wafer holder WH of the wafer table WTB, the position of the grating 24 on the wafer table WTB is slightly changed by the acceleration of the wafer table WTB. There is no. Therefore, highly accurate position measurement can be performed while accelerating wafer table WTB. Therefore, for example, exposure can be started during acceleration, and high throughput can be expected.

  In the present embodiment, since the position of the wafer table WTB is measured at a point IAa immediately below the center of the exposure area IA, high-precision position measurement can be performed without Abbe error, and the measurement result can be obtained. It is possible to perform highly accurate exposure by controlling the position of the wafer during exposure.

  In the present embodiment, measurement light is propagated from the end surface of wafer table WTB through the interior thereof and is incident on grating 24. In the case of this configuration, for example, the size of the wafer table WTB in the Y-axis direction and the X-axis direction is larger than that in the configuration in which the measurement light is incident from the upper surface of the wafer table WTB and reflected by the bottom surface and incident on the grating 24. Can be small. Further, by reducing the angle θ between the measurement light and the grating 24, the size (height or thickness) of the wafer table WTB in the Z-axis direction can also be reduced. Therefore, by adopting the configuration of the encoder system of the present embodiment, wafer table WTB can be reduced in size.

In the above embodiment, a pair of Y encoders 16Y ₁ and 16Y ₂ are provided to measure the position information of wafer table WTB in the θz direction, and θz along with the position information of wafer table WTB in the Y-axis direction is provided from the measurement results. The position information related to the direction was calculated. However, the present invention is not limited thereto, and a pair of X encoders may be provided, and position information regarding the θz direction may be calculated together with position information regarding the X axis direction of wafer table WTB from these measurement results. Also in this case, the measurement light of the pair of X encoders is spaced equidistant from each other by ± X on the axis parallel to the Y axis passing through the point IAa in the XY plane, and from the point IAa on the grating 24. It is assumed that the points are spaced equidistantly on the ± X side.

  Moreover, in the said embodiment, it may replace with each light source of the encoder system shown by FIG. 2 (A), and may use the light source which inject | emits two measurement light. The two measurement lights are generated inside the light source by, for example, branching laser light emitted from a semiconductor laser via a diffraction grating. The two measurement beams emitted enter the wafer table WTB via the side surface of the wafer table WTB, propagate through the wafer table WTB, and enter the grating 24. Then, at least one diffracted light derived from each of the two measurement lights among the plurality of diffracted lights generated in the grating 24 is synthesized on the same axis. The intensity of the combined light is detected using a photodetector. Here, the two measurement beams are incident on the same point (for example, the point IAa or the vicinity thereof) on the grating 24, and at least one diffracted beam derived from each measurement beam is synthesized on the same axis. In consideration of refraction when entering the side surface of the table WTB, the installation position of the light source, the emission angle of the two measurement lights, the inclination angle θ of the end surface of the wafer table WTB, and the pitch of the grating 24 are determined. To do. Even when this encoder system incorporating the light source is employed, the same effect as that obtained when the encoder system 16 having the configuration shown in FIG. 2A is used can be obtained.

  In the above embodiment, two measurement lights (first and second measurement lights) are incident from one end face of the wafer table in the X-axis direction (or Y-axis direction) and are derived from the two measurement lights. A case has been described in which an encoder configured to receive diffracted light generated by a grating to be received by a photodetector through the other end face of the wafer table in the X-axis direction (or Y-axis direction) has been described. However, the present invention is not limited to this. For example, an end surface on one side of the wafer table in the X-axis direction (or Y-axis direction) is configured by a beam splitter, and a part of each of the first and second measurement lights is placed inside the wafer table via the beam splitter. One of the first and second measurement lights reflected by the beam splitter (the end face) is incident and diffracted light derived from the first and second measurement lights from the grating provided on the ceiling of the wafer table. The present invention is also suitably applied to a mobile system or an exposure apparatus that uses an encoder configured to be coaxially combined with each other and to detect the intensity of interference light of the two sets of combined light with a photodetector. can do.

  In the embodiment and the modification, at least a part of the wafer table WTB is made of a material (such as synthetic quartz) that can transmit the measurement laser light of the encoder system. You may comprise with a hollow frame member. In this case, a transparent member may be provided in the opening of the frame member to seal the inside, or the temperature inside the frame member may be adjustable. Including the case where the wafer table is constituted by a hollow frame member or the like, in the above embodiment, of the constituent parts of the encoder body, the part that becomes the heat source (light source, detector, etc.) and the part that does not become the heat source (optical system etc.) It is also possible to adopt a configuration in which the two are separated and connected by an optical fiber.

  In the above-described embodiment, the case where the exposure apparatus includes a single wafer stage has been described. However, the present invention is not limited to this. For example, US Pat. No. 6,590,634, US Pat. No. 5,969,441 As disclosed in US Pat. No. 6,208,407, etc., the present invention can also be applied to an exposure apparatus including a plurality of wafer stages. Further, as disclosed in, for example, US Pat. No. 6,897,963, the present invention relates to an exposure apparatus including a stage apparatus including a wafer stage and a measurement stage that can move independently of the wafer stage. It is also possible to apply.

  Note that the present invention can also be applied to, for example, an immersion exposure apparatus disclosed in International Publication No. 2004/053955 pamphlet and US Patent Application Publication No. 2005/0259234 corresponding thereto. In this case, instead of the movable mirror 17, a reflection surface is formed on the side surface of the wafer table WTB so that the upper surface of the wafer table WTB including the wafer W becomes a completely flat same surface as a whole. desirable.

  In addition, the projection optical system in the exposure apparatus of the above embodiment 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 projected image may be an inverted image or an erect image. Further, the above-described exposure area IA is an on-axis area including the optical axis AX within the field of view of the projection optical system PL. For example, the exposure area IA is similar to the inline catadioptric system disclosed in WO 2004/107011. In addition, an off-axis region that does not include the optical axis AX may be used. The shape of the exposure area IA is not limited to a rectangle, and may be, for example, an arc, a trapezoid, or a parallelogram.

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. Further, as disclosed in, for example, US Pat. No. 7,023,610, a single wavelength laser beam in the infrared region or visible region oscillated from a DFB semiconductor laser or fiber laser is used as vacuum ultraviolet light. For example, a harmonic that is amplified by a fiber amplifier doped with erbium (or both erbium and ytterbium) and wavelength-converted into an ultraviolet region using a nonlinear optical crystal may be used.

  In the above embodiment, it is needless to say that the illumination light IL of the exposure apparatus is not limited to light having a wavelength of 100 nm or more, and light having a wavelength of less than 100 nm may be used. For example, the SOR or plasma laser is used as a light source to generate EUV (Extreme Ultraviolet) light in a soft X-ray region (for example, a wavelength region of 5 to 15 nm) and designed under the exposure wavelength (for example, 13.5 nm). The present invention can also be suitably applied to an EUV exposure apparatus that uses an all-reflection optical system and a reflective mask. In addition, the present invention can be applied to an exposure apparatus using a charged particle beam such as an electron beam or an ion beam.

  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. Instead of this reticle, for example, As disclosed in US Pat. No. 6,778,257, based on electronic data of a pattern to be exposed, an electronic mask (variable shaping mask, active pattern) that forms a transmission pattern, a reflection pattern, or a light emission pattern is disclosed. Also called a mask or an image generator, for example, a DMD (Digital Micro-mirror Device) which is a kind of non-light emitting image display element (spatial light modulator) may be used.

  Further, as disclosed in, for example, International Publication No. 2001/035168, an exposure apparatus (lithography system) that forms line and space patterns on a wafer by forming interference fringes on the wafer. The present invention can be applied.

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

  The apparatus for forming a pattern on an object is not limited to the above-described exposure apparatus (lithography system), and the present invention can also be applied to an apparatus for forming a pattern on an object by, for example, an inkjet method.

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

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

  The moving body system of the present invention is not limited to an exposure apparatus, but may be a substrate processing apparatus (for example, a laser repair apparatus, a substrate inspection apparatus, etc.), a sample positioning apparatus, a wire bonding apparatus, etc. in other precision machines. The present invention can also be widely applied to apparatuses including a moving body such as a stage that moves in the two-dimensional plane.

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

  As described above, the mobile system of the present invention is suitable for moving while holding an object. The exposure apparatus and exposure method of the present invention are suitable for forming a pattern on an object by irradiation with an energy beam. The device manufacturing method of the present invention is suitable for manufacturing a highly integrated device.

It is the schematic which shows the exposure apparatus which concerns on this embodiment. 2A is a perspective view showing the positional relationship between the components of the wafer table and the encoder system in FIG. 1, and FIG. 2B is a projection view showing the optical path of the measurement light emitted by the encoder system. FIG. 3A to FIG. 3C are diagrams for explaining the position measurement of the wafer table using the encoder system. It is a block diagram which shows the structure of the control system of exposure apparatus.

Explanation of symbols

12 ... illumination system (part of the patterning device), 16X ... X _encoder, 16Y 1, 16Y ₂ ... Y _{encoders, 16Xa, 16Ya 1, 16Ya 2} ... light _{source, 16Xb, 16Yb 1, 16Yb 2} ... photodetector, 24 ... Two-dimensional grating, 100 ... exposure apparatus (pattern forming apparatus), IAa ... predetermined point, IL ... illumination light (energy beam), PL ... projection optical system (part of patterning apparatus), Lx1, Ly1 ₁ , Ly1 ₂ ... measurement Light, Lx2, Ly2 ₁ , Ly2 ₁ ... diffracted light, W ... wafer (object), WTB ... wafer table (moving body, table).

Claims (41)

The object can be held and moved substantially along a predetermined plane, and a grating is arranged on the back side of the object along a plane substantially parallel to the predetermined plane so that light of a predetermined wavelength can travel inside. A moving body;
First and second measurement points having different positions with respect to the direction orthogonal to the measurement direction within the predetermined plane of the grating from the outside of the movable body through one side surface of the movable body intersecting the predetermined plane, Second measurement light is respectively incident, diffracted light from the grating derived from the first and second measurement lights is received, and position information regarding the measurement direction and the rotation direction of the movable body in the predetermined plane is measured. With a measurement system;
And a driving system that drives the moving body based on position information of the moving body.   The direction in which the orthogonal projection of the first and second measurement light incident on the predetermined plane through the one side surface of the movable body with respect to the predetermined plane intersects the measurement direction within the predetermined plane. The mobile system according to claim 1.   3. The mobile body system according to claim 1, wherein the first and second measurement lights incident from the outside to the inside of the mobile body through the one side surface of the mobile body are orthogonal to the one side surface in a side view. .   The mobile body system according to any one of claims 1 to 3, wherein the one side surface of the mobile body includes an inclined surface that forms an acute angle with respect to the predetermined plane.   5. The measurement system according to claim 1, wherein the measurement system receives diffracted light from the grating derived from the first and second measurement lights via another side surface different from the one side surface of the moving body. The mobile system according to one item. The one side surface is a first side surface of the movable body extending in a uniaxial direction parallel to the predetermined plane,
The other side surface is a second side surface of the movable body that extends in the uniaxial direction on the opposite side to the one side surface and a direction perpendicular to the uniaxial direction,
The measurement system causes at least one first and second measurement light to enter the movable body through the first side surface, and causes the second diffracted light derived from the first and second measurement lights to be the second. The mobile body system according to claim 5, comprising a first measuring device that receives light through each side surface.   The mobile system according to claim 6, wherein the first measurement device irradiates each of the first and second measurement lights and receives at least two of the diffracted lights.   The first measurement device irradiates the first and second measurement points on the grating with the two first and second measurement beams, respectively, and at least each of the two diffracted beams combined on the same axis. The mobile system according to claim 6, which receives light. The grating includes a diffraction grating having the uniaxial direction as a periodic direction,
The mobile body system according to any one of claims 6 to 8, wherein the first measurement device measures position information of the mobile body in the uniaxial direction. The movable body has third and fourth side surfaces extending in a direction perpendicular to the uniaxial direction within the predetermined plane,
The measurement system causes at least one third and fourth measurement light to enter the movable body via one of the third and fourth side surfaces, and the diffraction derived from the third and fourth measurement lights. The moving body system according to any one of claims 6 to 9, further comprising a second measuring device that receives light via the other of the third and fourth side surfaces.   11. The mobile body system according to claim 10, wherein the second measurement device irradiates each one of the third and fourth measurement lights and receives at least each of the two diffracted lights.   The second measurement device irradiates each of the third and fourth measurement lights on the grating to the third and fourth measurement points, and receives at least each of the two diffracted lights synthesized on the same axis. The mobile system according to claim 10. The grating includes a diffraction grating whose periodic direction is the perpendicular direction;
The mobile body system according to any one of claims 10 to 12, wherein the second measurement device measures position information regarding the vertical direction of the mobile body and rotation information within the predetermined plane.   The movable body includes a holding member that holds the object, the grating is disposed on a back surface thereof, and a table on which the holding member is mounted and through which the measurement light is transmitted. The moving body system as described in any one of Claims.   The movable body system according to claim 14, wherein the holding member is detachable from the table.   The moving body is provided on the one surface side of the transmitting member on which the light is incident and the grating is formed on one surface substantially parallel to the predetermined plane, and holding the object and on the transmitting member. The moving body system according to any one of claims 1 to 13, comprising a holding member.   The mobile system according to any one of claims 1 to 16, wherein the grating is a two-dimensional grating having two directions orthogonal to each other within the predetermined plane as a periodic direction.   The movable body system according to any one of claims 1 to 17, wherein the measurement system irradiates the grating with the measurement light without reflecting the measurement light inside the movable body. An exposure apparatus that forms a pattern on an object by irradiation with an energy beam,
A patterning device for irradiating the object with the energy beam;
An exposure apparatus comprising: the moving body system according to claim 1, wherein the object irradiated with an energy beam is held by the moving body.   The movable body includes a table through which light from the measurement system passes, and a holding member capable of holding the object and provided on the table, and the grating is formed on the table or the holding member. The exposure apparatus according to claim 19.   21. The exposure apparatus according to claim 19, wherein the light incident on the inside of the moving body is irradiated to a predetermined point in an irradiation area of the energy beam.   The exposure apparatus according to any one of claims 19 to 21, wherein the predetermined point to which light incident on the moving body is irradiated is an exposure center of the patterning apparatus. A device manufacturing method comprising:
Exposing the substrate using the exposure apparatus according to any one of claims 19 to 22;
Developing the exposed substrate; and a device manufacturing method. An exposure method for irradiating an object with an energy beam to form a predetermined pattern on the object,
A movable body that holds the object and has a grating disposed along a surface substantially parallel to the predetermined plane on the back surface side of the object and capable of traveling light of a predetermined wavelength along the predetermined plane. First and second measurement points that are different in position with respect to a direction orthogonal to the measurement direction in the predetermined plane of the grating from the outside of the movable body via one side surface of the movable body that intersects the predetermined plane. The first and second measurement lights are respectively incident on the first and second measurement lights, and the diffraction light from the grating derived from the first and second measurement lights is received, and the position of the movable body in the predetermined plane and the rotation direction is determined. Measuring information;
And a step of driving the moving body based on the position information of the moving body.   In the measuring step, the first and second measurement lights are obtained from a predetermined direction in which an orthogonal projection direction of the measurement light with respect to the predetermined plane intersects the measurement direction within the predetermined plane. The exposure method according to claim 24, wherein the light is incident on the inside of the moving body from the outside through one side surface.   In the measuring step, the first and second measurement lights are incident on the inside of the moving body from the outside through the one side face of the moving body from a direction orthogonal to the one side face in a side view. The exposure method according to 24 or 25.   27. The exposure method according to any one of claims 24 to 26, wherein the one side surface of the movable body is an inclined surface that forms an acute angle with the predetermined plane.   28. The method according to any one of claims 24 to 27, wherein in the measuring step, diffracted light from the grating derived from the first and second measurement lights is received through another side surface different from the one side surface of the moving body. The exposure method according to claim 1. The one side surface is a first side surface of the movable body extending in a uniaxial direction parallel to the predetermined plane,
The other side surface is a second side surface of the movable body that extends in the uniaxial direction on the opposite side to the one side surface and a direction perpendicular to the uniaxial direction,
In the measuring step, at least one first and second measurement light is incident on the inside of the moving body via the first side surface, and the diffracted light derived from the first and second measurement light is incident on the first side. The exposure method according to claim 28, further comprising a first measurement step of receiving light through two side surfaces.   30. The exposure method according to claim 29, wherein in the first measurement step, each one of the first and second measurement lights is irradiated and at least each of the two diffracted lights is received.   In the first measurement step, each of the two first and second measurement lights is irradiated to the first and second measurement points on the grating, respectively, and at least each of the two diffracted lights synthesized on the same axis is applied. 30. The exposure method according to claim 29, which receives light. The grating includes a diffraction grating having the uniaxial direction as a periodic direction,
32. The exposure method according to any one of claims 29 to 31, wherein in the first measurement step, position information of the moving body in the uniaxial direction is measured. The movable body has third and fourth side surfaces extending in a direction perpendicular to the uniaxial direction within the predetermined plane,
In the measuring step, at least one third and fourth measurement light is incident on the inside of the moving body via one of the third and fourth side surfaces, and the measurement is derived from the third and fourth measurement lights. The exposure method according to any one of claims 29 to 32, further comprising a second measurement step of receiving diffracted light through the other of the third and fourth side surfaces.   34. The exposure method according to claim 33, wherein in the second measurement step, each one of the third and fourth measurement lights is irradiated and at least each of the two diffracted lights is received.   In the second measurement step, each of the two third and fourth measurement lights is irradiated to the third and fourth measurement points on the grating, respectively, and at least each of the two diffracted lights synthesized on the same axis is received. The exposure method according to claim 33. The grating includes a diffraction grating whose periodic direction is the perpendicular direction;
36. The exposure method according to any one of claims 33 to 35, wherein in the second measurement step, position information relating to the vertical direction and the rotation direction of the movable body is measured.   37. The exposure method according to any one of claims 24 to 36, wherein a two-dimensional grating having a periodic direction in two directions orthogonal to each other in the predetermined plane is used as the grating.   The exposure method according to any one of claims 24 to 37, wherein in the measuring step, the grating is irradiated with each measurement light without being reflected inside the movable body.   The exposure method according to any one of claims 24 to 38, wherein the light incident on the inside of the moving body is irradiated to a predetermined point in an irradiation region of the energy beam.   The exposure method according to claim 39, wherein the predetermined point irradiated with the light incident on the inside of the moving body is an exposure center. Exposing a substrate as the object using the exposure method according to any one of claims 24 to 40;
Developing the exposed substrate; and a device manufacturing method.

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