JP2014138078A - Conveyance system and conveyance method, exposure device and exposure method, and method of manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To place a wafer on a stage without causing distortion.SOLUTION: Distribution of holding force (suction force) to hold a wafer of a loading desk 121, namely the distribution of the suction force to hold the wafer of a wafer holder WH corresponding to arrangement of a plurality of Bernoulli cups 124 is set, namely vacuum holes 135 of the wafer holder WH are arranged. As a result, a wafer W is held using the loading desk 121 and conveyed onto the wafer holder WH, and the wafer is held using the wafer holder WH, thereby enabling placing the wafer on a wafer stage WST without causing distortion. Then, high overlapping accuracy of patterns is made possible to be maintained.

Description

  The present invention relates to a transport system and a transport method, an exposure apparatus and an exposure method, and a device manufacturing method, and in particular, the object is placed on an object holding member provided with an object holding unit that holds one surface of a plate-like object by suction. The present invention relates to a transport system and a transport method for transport, an exposure apparatus including the transport system, an exposure method using the transport method, a device manufacturing method using the exposure apparatus, and a device manufacturing method using the exposure method.

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

  Wafers exposed by these exposure apparatuses are becoming larger year by year. Currently, wafers with a diameter of 300 mm (300 mm wafers) to wafers with a diameter of 450 mm (450 mm wafers) are becoming mainstream. In the case of a 450 mm wafer, the number of dies (chips) that can be taken from a single wafer is more than twice the number in the case of a current 300 mm wafer, and the manufacturing cost per chip can be greatly reduced.

  Since the thickness of the wafer is constant while the wafer is increased in size, it is expected that a more careful handling will be required in transferring a 450 mm wafer as compared with a 300 mm wafer. Therefore, it has been proposed to place the wafer on the wafer stage by holding the wafer in a non-contact manner by ejecting air toward the wafer surface from above using a Bernoulli chuck (for example, Patent Document 1). reference). Here, the inventor has a certain distribution of the holding force (suction force) for holding the wafer of the Bernoulli chuck, and the frictional resistance that the wafer receives from the wafer stage (wafer holder) is also formed between them (by the squeeze effect). A certain distribution is generated by the repulsive force received from the air film. Then, it was clarified that the wafer loaded on the wafer holder is distorted due to the balance between the distribution of the holding force (suction force) and the distribution of the frictional resistance. Due to the distortion of the wafer, for example, it is expected that the accuracy of alignment measurement (detection of a mark on the wafer) is lowered and it is difficult to maintain high pattern overlay accuracy.

US Patent Application Publication No. 2010/0297562

  The present invention has been made under the circumstances described above. From a first viewpoint, the present invention conveys the object to an object holding member provided with an object holding portion that holds one surface of the plate-like object by suction. A suction system provided above the object holding member at a predetermined loading position and capable of sucking the object from the other side opposite to the one surface from above without contact; and the suction A drive device that moves the member relative to the object holding portion in the vertical direction, and a position at which the suction force generated by the suction member acts on the other surface is placed on the object holding portion. The conveyance system is set to have a predetermined relationship with respect to a distribution of an adsorption force acting on the one surface of the object and adsorbing the object.

  According to this, the position at which the suction force generated by the suction member acts on the other surface is predetermined with respect to the distribution of the suction force that attracts the object that acts on one surface of the object placed on the object holding unit. Therefore, the object can be held without being distorted and transferred to the object holding member using the transfer system.

  According to a second aspect of the present invention, there is provided an exposure apparatus for forming a pattern on an object, the transport system of the present invention, and the object transported on the object holding member by the transport system using an energy beam. An exposure apparatus comprising: a pattern generation device that exposes and forms the pattern.

  According to this, the object can be exposed with high alignment accuracy by being conveyed onto the object holding member by the conveyance system of the present invention.

  From a third aspect, the present invention is a device manufacturing method including exposing an object using the exposure apparatus of the present invention and developing the exposed object.

  From a fourth viewpoint, the present invention is a transport method for transporting an object to an object holding member provided with an object holding portion for holding one surface of a plate-like object by suction, and the above-described method is performed at a predetermined loading position. Above the object holding member, sucking the object from the upper side in a non-contact manner on the other surface opposite to the one surface, and moving the suction member relative to the object holding portion in the vertical direction And a position where the suction force generated by the suction member acts on the other surface and a position where the suction force that attracts the object by the object holding portion acts on the one surface is set in a predetermined relationship. It is the conveyance method to do.

  According to this, the position where the suction force generated by the suction member acts on the other surface and the position where the suction force that attracts the object with the object holding portion acts on the one surface are set in a predetermined relationship, so that the object Can be held without distortion and conveyed to the object holding member.

  According to a fifth aspect of the present invention, the plate-like object is transported on the object holding member by the transport method of the present invention, and the object held on the object mounting member after the transport is energized. Exposing with a beam to form a pattern on the object.

  According to this, it is possible to expose the object with high alignment accuracy by transporting the object without causing distortion by the transport method of the present invention.

  From a sixth aspect, the present invention is a device manufacturing method including exposing an object by the exposure method of the present invention and developing the exposed object.

It is a figure which shows schematically the structure of the exposure apparatus which concerns on one Embodiment. FIGS. 2A and 2B are a cross-sectional view and a bottom view, respectively, schematically showing the configuration of the loading unit and the loading disk, respectively. It is a top view which shows the structure of a wafer stage. FIG. 2 is a block diagram showing a main configuration of a control system of the exposure apparatus in FIG. 1. FIGS. 5A to 5D are diagrams showing simulation results of changes over time in distortion generated in the wafer when the wafer is held using the loading unit, and FIG. 5E is a diagram illustrating the wafer using the loading unit. It is a figure which shows the simulation result of the distortion which arises on a wafer after loading on a wafer holder and carrying out vacuum suction. 6A to 6C are diagrams for explaining a procedure for loading a wafer onto a wafer stage using a loading unit (particularly, a procedure for holding a wafer using a loading disk) (Part 1). ~ 3). FIGS. 7A to 7C are views (Nos. 4 to 6) for explaining a procedure for loading a wafer onto a wafer stage using a loading unit. FIGS. 8A and 8B are views (Nos. 7 and 8) for explaining a procedure for loading a wafer onto a wafer stage using a loading unit.

  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 projection exposure apparatus, a so-called scanner. As will be described later, in the present embodiment, a projection optical system PL is provided. In the following description, a reticle and wafer are arranged in a direction perpendicular to the Z-axis direction parallel to the optical axis AX of the projection optical system PL and in a plane perpendicular to the Z-axis direction. And the direction perpendicular to the Z and Y axes is the X axis direction, and the rotation (tilt) directions around the X, Y, and Z axes are θx, θy, And the θz direction will be described.

  The exposure apparatus 100 includes an illumination system IOP, a reticle stage RST that holds a reticle R, a projection unit PU that projects a pattern image formed on the reticle R onto a wafer W coated with a sensitive agent (resist), and a wafer W. A wafer stage WST that holds and moves in the XY plane, a loading unit 120 that loads and unloads the wafer W onto and from the wafer stage WST, a control system thereof, and the like are provided.

  The illumination system IOP includes a light source and an illumination optical system connected to the light source via a light transmission optical system, and is slit-like illumination that extends in the X-axis direction on the reticle R defined by the reticle blind (masking system). The area IAR is illuminated with substantially uniform illuminance by illumination light (exposure light) IL. The configuration of the illumination system IOP is disclosed in, for example, US Patent Application Publication No. 2003/0025890. Here, as an example, ArF excimer laser light (wavelength 193 nm) is used as the illumination light IL.

  Reticle stage RST is arranged below illumination system IOP. On reticle stage RST, reticle R having a circuit pattern or the like formed on its pattern surface is placed. The reticle R is fixed on the reticle stage RST, for example, by vacuum suction.

  The reticle stage RST can be finely driven in a horizontal plane (XY plane) by a reticle stage drive system 11 (not shown in FIG. 1, see FIG. 4) including a linear motor, for example, and also in a scanning direction (Y-axis direction). It is possible to drive within a predetermined stroke range. Position information of the reticle stage RST in the XY plane (including rotation information in the θz direction) is formed on the end face of the reticle stage RST by a reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 14. Measured at a resolution of about 0.25 nm, for example. The measurement result of reticle interferometer 14 is supplied to main controller 20 (not shown in FIG. 1, see FIG. 4).

  Projection unit PU is arranged below reticle stage RST. The projection unit PU includes a lens barrel 40 and a projection optical system PL held in the lens barrel 40. As the projection optical system PL, for example, a refractive optical system including a plurality of optical elements (lens elements) arranged along the optical axis AXp 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, 1/5 times, or 1/8 times). For this reason, when the illumination area IAR on the reticle R is illuminated by the illumination light IL from the illumination system IOP, the reticle R in which the first surface (object surface) of the projection optical system PL and the pattern surface are substantially coincided with each other is arranged. With the illumination light IL that has passed through the projection optical system PL (projection unit PU), a reduced image of the circuit pattern of the reticle R in the illumination area IAR (a reduced image of a part of the circuit pattern) is projected through the projection optical system PL (projection unit PU). Is formed in a region (hereinafter also referred to as an exposure region) IA that is conjugated to the illumination region IAR on the wafer W, which is disposed on the second surface (image surface) side of the wafer W, the surface of which is coated with a resist (sensitive agent). . Then, by synchronous driving of reticle stage RST and wafer stage WST, reticle R is moved relative to illumination area IAR (illumination light IL) in the scanning direction (Y-axis direction) and 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 transferred to the shot area. .

  Wafer stage WST is driven on stage base 22 with a predetermined stroke in the X-axis direction and Y-axis direction by stage drive system 24 including a linear motor and the like, and in Z-axis direction, θx direction, θy direction, and θz direction. It is driven minutely. Instead of wafer stage WST, a first stage that moves in the X-axis direction, the Y-axis direction, and the θz direction, and a second stage that finely moves in the Z-axis direction, θx direction, and θy direction on the first stage; It is also possible to use a stage apparatus comprising

  On wafer stage WST, as shown in FIGS. 2A and 3, a wafer holder WH is provided. Wafer holder WH has a pin chuck WHP for supporting wafer W, and a plurality of vacuum holes 135 having one end communicating with pin chuck WHP are provided through wafer stage WST. The other end of the vacuum hole 135 is connected to a vacuum source (negative pressure source) such as a vacuum pump. As will be described later, the plurality of vacuum holes 135 are arranged coaxially with their central axes corresponding to the arrangement of the plurality of Bernoulli cups 124 provided on the loading disk 121. Wafer W is placed on wafer holder WH (pin chuck WHP), and air in pin chuck WHP is exhausted out of wafer stage WST through a plurality of vacuum holes 135 (air in pin chuck WHP is made negative pressure). ), The wafer W is attracted to the pin chuck WHP, whereby the wafer W is held on the wafer holder WH (that is, the wafer stage WST).

  Further, CT pin 140 that supports the back surface of wafer W is provided on wafer stage WST so as to be able to be taken in and out of wafer holder WH. On the wafer stage WST, a reference plate FP whose surface is the same height as the surface of the wafer W is fixed. On the surface of the reference plate FP, a reference mark used for baseline measurement of the alignment detection system AS, a pair of reference marks detected by a reticle alignment detection system described later, and the like are formed.

  Position information of wafer stage WST in the XY plane (including rotation information (yaw amount (rotation amount θz in θz direction), pitching amount (rotation amount θx in θx direction), rolling amount (rotation amount θy in θy direction))) Is always measured by a laser interferometer system (hereinafter referred to as “interferometer system”) 18 via a movable mirror 16 (a reflecting surface formed on the end face of wafer stage WST) with a resolution of about 0.25 nm, for example. Is done. The measurement result is supplied to the main controller 20 (see FIG. 4). Main controller 20 controls the position of wafer stage WST in the XY plane (including rotation in the θz direction) via stage drive system 24 in accordance with the measurement result of interferometer system 18.

  Although not shown in FIG. 1, the position and the amount of tilt in the Z-axis direction on the surface of the wafer W are different from those of the oblique incidence method disclosed in, for example, US Pat. No. 5,448,332. It is measured by a focus sensor AF (see FIG. 4) comprising a point focus position detection system. The measurement result of the focus sensor AF is also supplied to the main controller 20 (see FIG. 4).

  An alignment detection system AS that detects alignment marks and reference marks formed on the wafer W is provided on the side surface of the lens barrel 40 of the projection unit PU. As an example of the alignment detection system AS, a mark is illuminated with broadband light such as a halogen lamp, and the mark position is measured by image processing of the mark image, which is a type of image-forming alignment sensor. An FIA (Field Image Alignment) system is used.

  In exposure apparatus 100, a pair of TTR (Through The Reticle) alignment systems using light having an exposure wavelength disclosed in, for example, US Pat. No. 5,646,413, for example, above reticle stage RST. A reticle alignment detection system 13 (not shown in FIG. 1, refer to FIG. 4) is provided. The detection signal of the reticle alignment detection system 13 is supplied to the main controller 20 (see FIG. 4).

  The loading unit 120 is disposed in the vicinity of the alignment detection system AS. A place where the loading unit 120 is disposed is called a loading position.

  2A and 2B are a cross-sectional view and a bottom view of the loading unit 120, respectively. The loading unit 120 includes a drive unit 122, a loading disk 121, an air supply unit (not shown), and the like.

Driver 122, other the projection optical system PL (projection unit PU) drive 122 ₀ which is fixed through a frame that supports (not shown) to the vibration isolating member (not shown) to the end drive unit 122 ₀ end comprises a movable shaft 122 ₁ which is fixed to the top of the loading disk 121. Drive 122 ₀ includes a power source such as a voice coil motor or the like. Driver 122, by using the driving device 122 _0, the movable shaft 122 ₁ by driving in the direction of the white arrow (Z-axis direction), moves up and down the loading disk 121.

The loading disk 121 includes a disk-shaped disk body 123, a plurality of Bernoulli cups 124 (124 ₀ , 124 ₁ , 124 ₂ ), a gap sensor (not shown), a temperature sensor 128, three imaging elements 129, and the like.

Among the plurality of Bernoulli cups 124, one Bernoulli cups 124 ₀ at the center of the bottom surface of the disk body 123, four Bernoulli cups 124 ₁ around its, are further arranged eight Bernoulli cup 124 ₂ around their (See FIG. 2B). Pipes 125 for supplying air are connected to the plurality of Bernoulli cups 124. In the present embodiment, a common pipe 125 ₁ is connected to the Bernoulli cups 124 ₀ and 124 ₁ , and another common pipe 125 ₂ is connected to the Bernoulli cup 124 ₂ , thereby constituting an independent air supply system. The Bernoulli cup 124 (124 ₀ , 124 ₁ , 124 ₂ ) and the pipe 125 (125 ₁ ) are set so that the conductance received by the air ejected from each Bernoulli cup 124 is equal to each other at least for each independent air supply system. , 125 ₂ ).

Each Bernoulli cup 124 (124 ₀ , 124 ₁ , 124 ₂ ) faces the disc main body 123 by ejecting air using the Bernoulli effect (an effect that the fluid pressure decreases as the flow velocity increases). A negative pressure is generated between the wafer W and the wafer W. The loading disk 121 sucks the wafer W using this negative pressure, and holds the wafer W from above without contact. The separation distance between the disk main body 123 and the wafer W held by the disk main body 123 is determined by the flow velocity of air ejected from each Bernoulli cup 124 (and the weight of the wafer W).

In the present embodiment, each Bernoulli cup 124 (124 ₀ , 124 ₁ , 124 ₂ ) has a cylindrical shape, and the surface facing the wafer W is approximately annular or circular.

An air supply unit (not shown) is provided for each air supply system. That is, an independent air supply unit (not shown) is connected to each of the pipes 125 (125 ₁ , 125 ₂ ). Thus, independently of the through pipe 125 ₁ of air to the Bernoulli cup ₁₂₄ 0, 124 ₁ is supplied, air is supplied to the Bernoulli cup 124 ₂ via the pipe 125 _2. As will be described later, air having a different flow velocity is supplied to each air supply system (spouted from the Bernoulli cup 124) and exerts a certain (non-uniform) distribution of adsorption force (suction force) on the wafer W. Thus, the shape of the wafer W can be changed. Therefore, for example, the wafer W can be held flat by adjusting the suction force of the Bernoulli cup while monitoring the shape of the wafer W.

  As will be described later, the movement of the wafer W in the Z-axis direction, the θx direction, and the θy direction is restricted by being held on the loading disk 121, and the back surface is supported by CT pins 140 that are taken in and out of the wafer stage WST. This restricts movement in the X-axis direction, the Y-axis direction, and the θz direction.

  A plurality of gap sensors (not shown) are arranged on the bottom surface of the disc main body 123 so as to avoid the plurality of Bernoulli cups 124. The gap sensor (not shown) includes, for example, a capacitance sensor, and measures a separation distance between the loading disk 121 (disk main body 123) and the wafer W held by the loading disk 121 (disk main body 123). The result is supplied to the main controller 20. Main controller 20 determines the shape of wafer W from the measurement results from the plurality of gap sensors and the arrangement of the gap sensors.

The temperature sensor 128 includes, for example, a platinum resistor, a thermistor, and the like. The temperature sensor 128 is provided at the bottom of the disc body 123 and is disposed in the vicinity of one of the plurality of Bernoulli cups 124 (Bernoulli cup 124 ₂ in the present embodiment). The probe portion projects into a gap (usually a size of 200 to 400 μm) between the bottom surface of the disk main body 123 and the surface of the wafer W held by the loading disk 121. Temperature sensor 128, the temperature of the air ejected from the Bernoulli cup 124 _2, measured in better resolution than 0.01 degrees.

  The three image sensors 129 include, for example, a CCD and the like, and are fixed to the side surface of the disk main body 123 (only one image sensor 129 is shown in FIG. 2A). One of the three image sensors 129 captures the notch (V-shaped notch (not shown)) of the wafer W when the loading disk 121 (disk main body 123) holds the wafer W, and the remaining two are Images the periphery of the wafer W. The imaging results of the three imaging elements 129 are supplied to the main controller 20. Based on the imaging results, main controller 20 uses the method disclosed in, for example, U.S. Pat. No. 6,624,433, and the like to shift the position and rotation (θz) of wafer W in the X-axis direction and Y-axis direction. Rotation) error.

  In addition, a wafer transfer arm 118 for transferring a wafer between a loading position (loading unit 120) and a coater / developer (C / D (not shown)) connected in-line to the exposure apparatus 100 is attached.

  A measurement stage MST is disposed in the vicinity of the loading position. The measurement stage MST is driven on the stage base 22 in the X axis direction and the Y axis direction by a measurement stage drive system (not shown) including a linear motor and the like. On the measurement stage MST, a line sensor (not shown) that measures the shape of the wafer W by irradiating the back surface of the wafer W held on the loading disk 121 in a line shape and receiving the reflected light. Is provided. Further, position information of the measurement stage MST in the XY plane is measured by a measurement stage position measurement system (not shown) including an interferometer system. The measurement result is supplied to the main controller 20.

  The loading unit 120 (drive unit 122, air supply unit (not shown), wafer transfer arm 118, etc.) is controlled by the main controller 20 (see FIG. 4).

  FIG. 4 shows the main configuration of the control system of the exposure apparatus 100. The control system is mainly configured of a main controller 20 including a microcomputer (or workstation) that performs overall control of the entire apparatus.

5A to 5D show the absolute value of distortion generated in the wafer W when the wafer W is held using the loading unit 120 (loading disk 121) (however, one Bernoulli cup 124 (124). ₂ ) shows the simulation result of the time change of the distortion generated in the vicinity of ₂ ). As shown in FIG. 5A, the distortion of the wafer cannot be confirmed before holding. When the wafer W is held using the loading disk 121, as shown in FIGS. 5B and 5C, the holding force (suction force) of each Bernoulli cup 124 (124 ₂ ) is distributed in an annular shape. Therefore, distortion occurs on the wafer corresponding to the shape. Even when the wafer W is placed on the wafer holder WH and the loading disk 121 is stopped, as shown in FIG. 5D, the distortion of the wafer W is recovered by the squeeze effect. It can be seen that some distortion remains due to the balance.

FIG. 5E shows a vector map of the distortion of the wafer W placed on the wafer holder WH using the loading disk 121 and vacuum-sucked as described above. It can be confirmed that a distortion of the distribution corresponding to the distribution of the holding force of the Bernoulli cup 124 (124 ₂ ) appears. Due to the distortion of the wafer, for example, it is expected that the accuracy of alignment measurement (detection of a mark on the wafer) is lowered and it is difficult to maintain high pattern overlay accuracy.

Therefore, in the exposure apparatus 100 of the present embodiment, as shown in FIGS. 2A, 2B, and 3, a plurality of vacuum holes 135 of the wafer holder WH are provided in the loading disk 121. The Bernoulli cup 124 (124 ₀ , 124 ₁ , 124 ₂ ) is provided in correspondence with the arrangement. Specifically, the vacuum holes 135 are arranged substantially coaxially with the central axis of each of the plurality of Bernoulli cups 124 (124 ₀ , 124 ₁ , 124 ₂ ). As described above, each Bernoulli cup 124 generates an annular distribution holding force (suction force). Therefore, when the wafer W held by the loading disk 121 is placed on the wafer holder WH, The vacuum hole 135 is arranged so as to coincide with the center of the holding force (suction force) distribution. Accordingly, it is expected that the holding force (distribution) by the Bernoulli cup 124 and the adsorption force (distribution) by the wafer holder WH are balanced, and the distortion of the wafer is improved.

  Further, the flow rate of the gas supplied to the Bernoulli cup 124 and the vacuum hole 135 of the wafer holder WH so that the holding force (suction force) of the Bernoulli cup 124 and the adsorption force (distribution) by the wafer holder WH are balanced in a predetermined state. One or both of the degree of vacuum supplied may be temporarily adjusted.

  Note that the vacuum hole 135 may be arranged around the distribution of the Bernoulli cup 124 without being limited to the center of the distribution of the holding force (suction force). Further, it is not always necessary to arrange the vacuum holes 135 corresponding to all the Bernoulli cups 124, and as long as the distortion of the wafer can be improved within the limit, the vacuum holes 135 are arranged corresponding to only some of the Bernoulli cups 124. It is good to do. Further, when the distribution of the holding force (suction force) of the Bernoulli cup 124 does not have a clear center like an annular shape, the vacuum hole 135 may be arranged in accordance with the approximate center of the distribution.

  Hereinafter, a process (holding operation) of holding the wafer W on the wafer holder WH using the loading unit 120 will be described.

  As a premise, it is assumed that the loading disk 121 is upward (+ Z direction) and the wafer stage WST is retracted other than the loading position. Further, it is assumed that the loading disk 121 is in a stopped state.

  Prior to the wafer holding operation, main controller 20 operates loading disk 121, that is, supplies air at a flow rate required to hold wafer W to a plurality of Bernoulli cups 124. Here, main controller 20 measures the temperature of the air ejected from the plurality of Bernoulli cups 124 using temperature sensor 128 so that the temperature of the air matches a predetermined temperature (or the temperature of wafer W). The air is heated using a temperature controller (not shown).

  Next, the wafer W is held using the loading unit 120 (loading disk 121).

  At this time, as shown in FIG. 6A, the wafer W provided with the sensitive layer (resist layer) by C / D (not shown) is moved by the wafer transfer arm 118 toward the loading position by a black arrow. It is conveyed in the direction (+ Y direction). When the wafer W is transferred to just below the loading disk 121, the main controller 20 drives the loading disk 121 in the direction of the white arrow (−Z direction) as shown in FIG. The lower surface of the disk 121 is brought close to the surface of the wafer W. Instead of or in addition to driving the loading disk 121, the wafer transfer arm 118 may be driven in the direction opposite to the white arrow (+ Z direction).

  When the lower surface of the loading disk 121 comes close to the surface of the wafer W to the order of 100 μm, the adsorption force of the loading disk 121 reaches the wafer W, and the wafer W is held on the loading disk 121 in a non-contact manner. Thereby, the movement of the wafer W in the Z-axis direction, the θx direction, and the θy direction is restricted. As shown in FIG. 6C, the main controller 20 finely drives the loading disk 121 holding the wafer W in the direction of the white arrow (+ Z direction), or instead of (or with this). The wafer transfer arm 118 is finely driven in the direction opposite to the white arrow (−Z direction), and the wafer transfer arm 118 that has released the wafer W is retracted in the direction of the black arrow (−Y direction).

  Main controller 20 measures the shape of wafer W held on loading disk 121 by using the plurality of gap sensors (not shown). Here, a line sensor (not shown) provided on the measurement stage MST may be used.

Main controller 20 determines the flow rate of air ejected from each of the plurality of Bernoulli cups 124 (124 ₀ , 124 ₁ , 124 ₂ ) based on the shape of wafer W, and adjusts the flow rate of air. For example, it is assumed that the wafer W is bent upwardly in a convex shape. A case, the main controller 20 increases the air flow rate with respect to the Bernoulli cup ₁₂₄ 0, 124 ₁ are ejected from the Bernoulli cup 124 _2. Thereby, a strong suction force acts on the peripheral portion with respect to the central portion of the wafer W. On the other hand, it is assumed that the wafer W is bent downward and convex. Such a case, the main controller 20, to reduce the air flow rate with respect to the Bernoulli cup ₁₂₄ 0, 124 ₁ are ejected from the Bernoulli cup 124 _2. Thereby, a weak suction force acts on the peripheral portion with respect to the central portion of the wafer W. As a result, the wafer W is held flat by the loading disk 121.

  Next, wafer W held on loading disk 121 is placed on wafer stage WST.

  The main controller 20 images the periphery (notch or the like) of the wafer W held on the loading disk 121 by using the three image sensors 129. Main controller 20 obtains the positional deviation and rotation (θz rotation) error of wafer W in the X-axis direction and Y-axis direction from these imaging results.

  As shown in FIG. 7A, main controller 20 moves wafer stage WST to the loading position. Here, main controller 20 positions wafer stage WST at a position and orientation that cancels the positional deviation and rotation error obtained above. Alternatively, the positional deviation and the rotation error obtained above may be stored, and the result may be corrected in the alignment measurement.

  When wafer stage WST is positioned immediately below loading disk 121, main controller 20 causes three CT pins 140 from inside wafer stage WST via a wafer holder (not shown) as shown in FIG. 7B. Are exposed in the direction of the black arrow (+ Z direction), and their tips are brought into contact with the back surface of the wafer W held on the loading disk 121 to support (suck) the wafer W. This further restricts the movement of the wafer W in the X-axis direction, the Y-axis direction, and the θz direction.

  The wafer W is held on the loading disk 121 so that movement in the Z-axis direction, θx direction, and θy direction is restricted, and the back surface is supported by three CT pins 140, so that the X-axis direction, Y When the movement in the axial direction and the θz direction is restricted, as shown in FIG. 7C, main controller 20 drives loading disk 121 in the direction of the white arrow (−Z direction). At the same time, the three CT pins 140 are moved in the direction of the black arrow (−Z direction) to be stored in the wafer stage WST (the holder WH. As shown in FIG. 8A, Wafer W is placed on wafer stage WST in a state where movement in the direction of six degrees of freedom is substantially restricted.

  When wafer W is placed on wafer stage WST, main controller 20 operates wafer holder WH, that is, exhausts air in pin chuck WHP to outside of wafer stage WST via a plurality of vacuum holes 135. Thus, the wafer W is sucked and held on the wafer holder WH (that is, the wafer stage WST), and the loading disk 121 is stopped.

  Finally, as shown in FIG. 8B, main controller 20 retracts loading disk 121 in the direction of the white arrow (+ Z direction).

  Here, the exposure operation of the exposure apparatus 100 of the present embodiment will be briefly described.

  Prior to exposure, main controller 20 uses a loading unit 120 to load wafer stage WST (wafer holder (wafer holder) (wafer)) on which a sensitive layer (resist layer) is provided by C / D (not shown) according to the procedure described above. (Not shown)).

  Main controller 20 detects an alignment mark (attached to a sample shot area on wafer W) provided on the surface of wafer W using alignment detection system AS, and performs alignment measurement (EGA). Thereby, the position of the shot area on the wafer W in the XY plane (further, the magnification in the scanning direction, the rotation around the optical axis AX, and the orthogonality) is determined. Details of alignment measurement (EGA) are described in, for example, Japanese Patent Laid-Open No. 6-349705.

  Main controller 20 calculates the relative positional relationship between the projection position of the pattern on reticle R (projection center of projection optical system PL) and each shot area on wafer W according to the result of alignment measurement (EGA). In accordance with the result, main controller 20 sequentially exposes the pattern of reticle R in the entire shot area on wafer W by scanning exposure.

  In the scanning exposure for each shot area on wafer W, main controller 20 monitors the measurement results of reticle interferometer 14 and interferometer system 18, and moves reticle stage RST and wafer stage WST to their respective scan start positions (acceleration). Move to the start position. Then, main controller 20 relatively drives both stages RST and WST in the Y-axis direction, but in opposite directions. Here, when both stages RST and WST reach their respective target speeds, the pattern area of reticle R starts to be illuminated by illumination light IL, and scanning exposure is started.

  Main controller 20 performs a reticle stage so as to maintain the speed Vr of reticle stage RST and the speed Vw of wafer stage WST in the Y-axis direction at a speed ratio corresponding to the projection magnification of projection optical system PL during scanning exposure. The RST and the wafer stage WST are driven synchronously.

  As reticle R moves in the Y-axis direction, the entire pattern area is illuminated by illumination light IL. At the same time, the pattern of the reticle R is transferred onto the wafer W by moving the wafer W in the Y-axis direction, but in the opposite direction to the reticle R. Thereby, the scanning exposure for one of the shot areas on the wafer W is completed.

  When the scanning exposure for one of the shot areas is completed, main controller 20 moves (steps) wafer stage WST to the scanning start position (acceleration start position) for the next shot area. Then, main controller 20 performs scanning exposure on the next shot area in the same manner as described above. The scanning exposure for the other shot areas is performed in the same manner. In this manner, the pattern of the reticle R is transferred to all the shot areas on the wafer W by repeating the step movement between the shot areas and the scanning exposure for each shot area.

  When the exposure is completed, main controller 20 unloads exposed wafer W from wafer stage WST (wafer holder (not shown)). Then, the next wafer W provided with a sensitive layer (resist layer) by C / D (not shown) is loaded onto wafer stage WST (wafer holder (not shown)) by the above-described procedure. That is, the wafer W on the wafer stage WST is exchanged. Main controller 20 repeats the exposure operation for a new wafer W in the same manner.

  As described above in detail, according to the exposure apparatus 100 according to the present embodiment, it corresponds to the distribution of the holding force (suction force) for holding the wafer of the loading disk 121 (that is, the arrangement of the plurality of Bernoulli cups 124). The distribution of the suction force for holding the wafer of the wafer holder WH (that is, the position where the vacuum hole 135 of the wafer holder WH is arranged) is set. This makes it possible to place the wafer on wafer stage WST without causing distortion. It is possible to maintain high pattern overlay accuracy.

  In the exposure apparatus 100 according to the present embodiment, the suction of holding the wafer of the wafer holder WH corresponding to the distribution of the holding force (suction force) for holding the wafer of the loading disk 121 (arrangement of a plurality of Bernoulli cups 124). Although the distribution of force is set (vacuum hole 135 of wafer holder WH is arranged), conversely, the distribution of suction force holding wafer of wafer holder WH (arrangement of vacuum hole 135 of wafer holder WH) corresponds to The distribution (suction force) of the holding force for holding the wafer of the loading disk 121 may be set (a plurality of Bernoulli cups 124 are arranged).

  Further, in the exposure apparatus 100 of the present embodiment, the loading unit 120 is configured using the loading disk (Bernoulli chuck) 121 using a plurality of Bernoulli cups 124, but the wafer is not limited to the plurality of Bernoulli cups 124 and is not contacted. The wafer holder WH in which the vacuum holes 135 are arranged corresponding to the distribution of the holding force is used for the loading disk of any principle to be held, so that the wafer is held without distortion and placed on the wafer stage WST. It is possible to place it.

  In the exposure apparatus 100 of the present embodiment, the loading position for loading the wafer W onto the wafer stage WST and the unloading position for unloading the wafer W from the wafer stage WST are arranged at the same position. Instead, they may be arranged at different positions, and a loading unit (unloading unit) 120 may be provided for each. As a result, the throughput of the wafer W can be expected to be improved because the wafer W can be loaded and unloaded in parallel with other operations.

  In the above-described embodiment, the case where the present invention is applied to a dry type exposure apparatus that exposes the wafer W without using liquid (water) has been described. No. 99/49504, European Patent Application Publication No. 1,420,298, International Publication No. 2004/055803, Japanese Patent Application Laid-Open No. 2004-289126 (corresponding US Pat. No. 6,952,253), etc. As disclosed, an exposure apparatus that forms an immersion space including an optical path of illumination light between a projection optical system and a wafer, and exposes the wafer with illumination light via the liquid in the projection optical system and the immersion space. The present invention can also be applied to. The present invention can also be applied to an immersion exposure apparatus disclosed in, for example, International Publication No. 2007/097379 (corresponding to US Patent Application Publication No. 2008/0088843).

  In the above embodiment, the case where the present invention is applied to a scanning exposure apparatus such as a step-and-scan method has been described. However, the present invention is not limited to this, and the present invention is applied to a stationary exposure apparatus such as a stepper. May be. The present invention can also be applied to a step-and-stitch reduction projection exposure apparatus, a proximity exposure apparatus, or a mirror projection aligner that synthesizes a shot area and a shot area. Further, as disclosed in, for example, US Pat. No. 6,590,634, US Pat. No. 5,969,441, US Pat. No. 6,208,407, etc. The present invention can also be applied to a multi-stage type exposure apparatus provided with a stage. Further, as disclosed in, for example, International Publication No. 2005/0774014, the present invention is also applied to an exposure apparatus having a measurement stage including a measurement member (for example, a reference mark and / or a sensor) separately from the wafer stage. The invention is applicable.

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

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

  In the above embodiment, it is needless to say that the illumination light IL of the exposure apparatus is not limited to light having a wavelength of 100 nm or more, and light having a wavelength of less than 100 nm may be used. For example, the present invention can be applied to an EUV exposure apparatus that uses EUV (Extreme Ultraviolet) light in a soft X-ray region (for example, a wavelength region of 5 to 15 nm). In addition, the present invention can be applied to an exposure apparatus using a charged particle beam such as an electron beam or an ion beam.

  Further, as disclosed in, for example, US Pat. No. 6,611,316, two reticle patterns are synthesized on a wafer via a projection optical system, and 1 on the wafer by one scan exposure. The present invention can also be applied to an exposure apparatus that double exposes two shot areas almost simultaneously.

  In the above embodiment, the object on which the pattern is to be formed (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.

  The use 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 a liquid crystal display element pattern to a square glass plate, an organic EL, a thin film magnetic head, 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 present invention can also be applied to an exposure apparatus that transfers a circuit pattern.

  An electronic device such as a semiconductor element includes a step of designing a function / performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and the exposure apparatus (pattern forming apparatus) of the above-described embodiment. And a lithography step for transferring the mask (reticle) pattern to 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.

20 ... main control unit, 100 ... exposure apparatus, 118 ... wafer transfer arm, 120 ... loading unit, 121 ... loading _disk 124 (124 _0, 124 1, 124 ₂₎ ... Bernoulli cup, ₁₂₅ (125 1, ₁₂₅ 2) ... Pipe, 128 ... Temperature sensor, 129 ... Image sensor, 135 ... Vacuum hole, 140 ... CT pin, PL ... Projection optical system, PU ... Projection unit, W ... Wafer, WH ... Wafer holder, WST ... Wafer stage.

Claims (10)

A transport system that transports an object to an object holding member provided with an object holding unit that holds one surface of a plate-like object by suction,
A suction member provided above the object holding member at a predetermined loading position and capable of sucking the object from the upper side in a non-contact manner on the other surface opposite to the one surface;
A drive device that moves the suction member relative to the object holding portion in the vertical direction; and
The position at which the suction force generated by the suction member acts on the other surface is a distribution of the suction force that attracts the object and acts on the one surface of the object placed on the object holding unit. A transport system set in a predetermined relationship. An opening that is provided in the object holding member so as to face the object held by the object holding unit and is connected to a negative pressure source that generates the suction force;
The transport system according to claim 1, wherein the opening is disposed at a position facing the position where the suction force acts on the other surface of the object through the object.   The transport system according to claim 1, wherein the suction member causes the suction force to act on the other surface at a plurality of positions. The suction member includes a support member facing the other surface, and a plurality of ejection members that are provided on the support member and generate the suction force by ejecting gas,
The transport system according to claim 2 or 3, wherein the ejection member and the opening are arranged coaxially.   The transport system according to any one of claims 1 to 4, wherein at least one of the suction force and the suction force is adjusted to be in a predetermined balanced state. An exposure apparatus that forms a pattern on an object,
The conveyance system according to any one of claims 1 to 5,
An exposure apparatus comprising: a pattern generation device configured to expose the object transported on the object holding member by the transport system with an energy beam to form the pattern. Exposing an object using the exposure apparatus according to claim 6;
Developing the exposed object. A transport method for transporting an object to an object holding member provided with an object holding unit for holding one surface of a plate-like object by suction,
Sucking the object above the object holding member at a predetermined carry-in position from the upper side in a non-contact manner on the other surface opposite to the one surface;
Moving the suction member relative to the object holding portion in the vertical direction,
A conveyance method of setting a predetermined relationship between a position where a suction force generated by the suction member acts on the other surface and a position where a suction force that attracts the object by the object holding unit acts on the one surface. Conveying the plate-like object onto the object holding member by the conveying method according to claim 8;
An exposure method comprising: exposing the object held by the object mounting member after conveyance with an energy beam to form a pattern on the object. Exposing an object by the exposure method according to claim 9;
Developing the exposed object.