JP6653068B2 - Holding apparatus and holding method, exposure apparatus and exposure method, and device manufacturing method - Google Patents

Description

  The present invention relates to a holding apparatus and a holding method, an exposure apparatus and an exposure method, and a device manufacturing method, and more particularly, to a holding apparatus and a method for holding an object, an exposure apparatus including the holding apparatus, and the holding method. The present invention relates to an exposure method and a device manufacturing method using the exposure method.

  2. Description of the Related Art Conventionally, in a lithography process for manufacturing an electronic device (micro device) such as a semiconductor element (such as an integrated circuit) or a liquid crystal display element, a step-and-repeat projection exposure apparatus (a so-called stepper) or a step-and-repeat method is mainly used. A scan type projection exposure apparatus (a so-called scanning stepper (also called a scanner)) or the like is used.

  Wafers exposed by these exposure apparatuses are increasing in size year by year. At present, a wafer having a diameter of 300 mm (300 mm wafer) to a wafer having a diameter of 450 mm (450 mm wafer) is becoming mainstream. In the case of a 450 mm wafer, the number of dies (chips) obtained from one wafer is more than twice the number of the current 300 mm wafer. Therefore, the manufacturing cost spent per chip can be significantly reduced.

  Since the thickness of the wafer is constant while the size of the wafer is increased, more careful handling is required when transporting a 450 mm wafer or the like as compared with a 300 mm wafer.

US Patent Application Publication No. 2010/0297562

According to a first aspect of the present invention, there is provided a holding device for holding an object, a holding member capable of holding by suction the placed object after the object has been placed on the holding member before the said retaining member there to adsorb the object, and sound pressure source for radiating sound pressure in mounted the object was in the holding member, even after said object has been placed on the holding member And a driving device that changes a position of the sound pressure source with respect to the holding member before the holding member sucks the object .

According to a second aspect of the present invention, there is provided an exposure apparatus for irradiating an energy beam to form a pattern on an object, comprising the holding device according to the first aspect , the exposure device being held by the holding member. an exposure device that irradiates the energy beam relative to the object, Ru is provided.

According to a third aspect of the present invention, there is provided a holding method for holding an object, wherein the object is placed on a holding member capable of holding the object by suction, and the object is placed on the holding member. before the holding member adsorbs the object even after that is location, and to radiate the generated sound pressure of the sound pressure source placed the object was in the holding member, the object is the holding member And changing the position of the sound pressure source with respect to the holding member after being placed on the holding member and before the holding member sucks the object .

According to a fourth aspect of the present invention, there is provided an exposure method for forming a pattern on an object by irradiating an energy beam, held by the holding member by using the holding method according to the third aspect the eXPOSURE method of irradiating the energy beam to the object, Ru is provided.

According to a fifth aspect of the present invention, there is provided a device manufacturing method including a lithography step, wherein the lithography step includes forming a pattern on an object using the exposure method according to the fourth aspect, Developing the object having a pattern formed thereon.

FIG. 1 is a diagram schematically illustrating a configuration of an exposure apparatus according to an embodiment. FIGS. 2A and 2B are a cross-sectional view and a bottom view, respectively, schematically showing the configuration of a loading unit and a loading disk. FIG. 2 is a block diagram illustrating a main configuration of a control system of the exposure apparatus in FIG. 1. 4 (A) and 4 (B) are diagrams showing experimental results for verifying the elimination of wafer distortion due to sound pressure excitation, and FIG. 4 (C) is a diagram showing a measurement position and a measurement direction of distortion on the wafer. It is. FIGS. 5A to 5C are diagrams for explaining a procedure for loading a wafer on a wafer stage using a loading unit (particularly, a procedure for holding a wafer using a loading disk) (part 1). To 3). FIGS. 6A to 6C are diagrams (parts 4 to 6) illustrating a procedure for loading a wafer on a wafer stage using a loading unit. FIGS. 7A to 7C are diagrams (parts 7 to 9) illustrating a procedure for loading a wafer on a wafer stage using a loading unit.

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

  FIG. 1 shows a schematic configuration of an exposure apparatus 100 according to one embodiment. The exposure apparatus 100 is a projection exposure apparatus of a step-and-scan method, a so-called scanner. As will be described later, a projection optical system PL is provided in the present embodiment. Hereinafter, a direction parallel to the optical axis AX of the projection optical system PL is defined as a Z-axis direction, and a reticle and a wafer are aligned in a plane orthogonal to the Z-axis direction. And the direction orthogonal to the Y-axis, the Z-axis, and the Y-axis is the X-axis direction, and the rotation (tilt) directions around the X-axis, the Y-axis, and the Z-axis are θx, θy, And the θz direction.

  The exposure apparatus 100 includes an illumination system IOP, a reticle stage RST holding the reticle R, a projection unit PU that projects an image of a pattern formed on the reticle R onto a wafer W coated with a photosensitive 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, and a control system therefor 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 has a slit-shaped illumination elongated in the X-axis direction on a reticle R defined by a reticle blind (masking system). The area IAR is illuminated with illumination light (exposure light) IL with substantially uniform illuminance. The configuration of the illumination system IOP is disclosed in, for example, US Patent Application Publication No. 2003/0025890. Here, as the illumination light IL, for example, an ArF excimer laser light (wavelength 193 nm) is used.

  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 mounted. Reticle R is fixed on reticle stage RST by, for example, 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. 3) including a linear motor and the scanning direction (Y-axis direction). Can be driven within a predetermined stroke range. Position information (including rotation information in the θz direction) of the reticle stage RST in the XY plane is formed on a movable mirror 12 (or an end face of the reticle stage RST) by a reticle laser interferometer (hereinafter, referred to as “reticle interferometer”) 14. , For example, at a resolution of about 0.25 nm. The measurement result of reticle interferometer 14 is supplied to main controller 20 (not shown in FIG. 1, see FIG. 3). Note that, instead of the interferometer, position information of the reticle stage RST in the XY plane may be obtained by an encoder.

  Projection unit PU is arranged below reticle stage RST. Projection unit PU includes a lens barrel 40 and a projection optical system PL held in lens barrel 40. As the projection optical system PL, for example, a refraction optical system including a plurality of optical elements (lens elements) arranged along an optical axis AXp parallel to the Z-axis direction is used. The projection optical system PL is, for example, bilateral telecentric and has a predetermined projection magnification (for example, 1/4, 1/5 or 1/8). 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 arranged such that the first surface (object surface) of the projection optical system PL and the pattern surface substantially coincide with each other. 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 by the projection optical system PL. Is formed in a region (hereinafter also referred to as an exposure region) conjugate to the illumination region IAR on the wafer W having a surface coated with a resist (sensitizer). . Then, by synchronous driving of reticle stage RST and wafer stage WST, reticle R is relatively moved in the scanning direction (Y-axis direction) with respect to illumination area IAR (illumination light IL), and exposure area IA (illumination light IL). Relative to the wafer W in 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. .

  The wafer stage WST is driven on the stage base 22 by a predetermined stroke in the X-axis direction and the Y-axis direction by a stage drive system 24 including a linear motor and the like, and is moved in the Z-axis direction, the θx direction, the θy direction, and the θz direction. Is minutely driven. Note that, 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, the θx direction, and the θy direction on the first stage, It is also possible to use a stage device equipped with

  As shown in FIG. 2A, a wafer holder WH is provided on wafer stage WST. The wafer W is held by the wafer holder WH by vacuum suction or the like. Further, CT pins 140 (see FIG. 2A) supporting the back surface of wafer W are provided in wafer stage WST so as to be able to be taken in and out of wafer holder WH.

  On wafer stage WST, a reference plate FP whose surface is the same as the surface of 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.

  Wafer stage WST position information on 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 constantly measured at a resolution of, for example, about 0.25 nm by a laser interferometer system (hereinafter, referred to as an “interferometer system”) 18 via a movable mirror 16 (a reflecting surface formed on an end face of the wafer stage WST). Is done. The measurement result is supplied to main controller 20 (see FIG. 3). Main controller 20 controls the position (including rotation in the θz direction) of wafer stage WST in the XY plane via stage drive system 24 according to the measurement result of interferometer system 18.

  Although not shown in FIG. 1, the position and the amount of tilt of the surface of the wafer W in the Z-axis direction can be determined by the oblique incidence method disclosed in, for example, US Pat. No. 5,448,332. It is measured by a focus sensor AF (see FIG. 3) including a point focal position detection system. The measurement result of the focus sensor AF is also supplied to the main controller 20 (see FIG. 3).

  An alignment detection system AS that detects an alignment mark and a reference mark formed on the wafer W is provided on a 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 (broadband) light such as a halogen lamp or the like, and is a type of an image processing type alignment sensor that measures a mark position by image processing the mark image. An FIA (Field Image Alignment) system is used.

  In the exposure apparatus 100, a pair of a TTR (Through The Reticle) alignment system using light of an exposure wavelength disclosed in, for example, US Pat. No. 5,646,413, is disposed above the reticle stage RST. The reticle alignment detection system 13 (not shown in FIG. 1, see FIG. 3) is provided. The detection signal of reticle alignment detection system 13 is supplied to main controller 20 (see FIG. 3).

  The loading unit 120 is arranged near the alignment detection system AS. The place where the loading unit 120 is arranged is called a loading position.

  2A and 2B show 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, a gap sensor (not shown), a temperature sensor 128, three imaging elements 129, an ultrasonic speaker 150, and the like.

  A plurality (eight in this embodiment) of Bernoulli cups 124 are arranged around the bottom surface of the disk main body 123 (see FIG. 2B). A pipe 125 for supplying air is connected to the plurality of Bernoulli cups 124 to form one air supply system. Note that the Bernoulli cup 124 and the pipe 125 are configured so that the conductance received by the air ejected from each of the Bernoulli cups 124 becomes equal to each other.

  The plurality of Bernoulli cups 124 use the Bernoulli effect (effect of decreasing the pressure of fluid as the flow velocity increases) to eject air, thereby creating a negative pressure between the disk main body 123 and the facing wafer W. The generated wafer W is sucked. Using the negative pressure, the loading disk 121 sucks the wafer W from above and holds the wafer W in a non-contact manner. The 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 the air ejected from each of the plurality of Bernoulli cups 124 (and the weight of the wafer W).

  As will be described later, the wafer W is held by the loading disk 121 to restrict the movement in the Z-axis direction, the θx direction, and the θy direction, and the back surface is supported by the CT pins 140 that are put in and out of the wafer stage WST. As a result, movements in the X-axis direction, the Y-axis direction, and the θz direction are restricted.

  A plurality of gap sensors (not shown) are arranged on the bottom surface of the disk 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 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 disk main body 123 and is arranged near any one of the Bernoulli cups 124. The probe portion protrudes into a gap (usually 200 to 400 μm in size) between the bottom surface of the disk main body 123 and the surface of the wafer W held by the loading disk 121. The temperature sensor 128 measures, for example, the temperature of air ejected from the Bernoulli cup 124 with a resolution better than 0.01 degrees.

  The three imaging elements 129 include, for example, a CCD and are fixed to the side surface of the disk main body 123 (only one imaging element 129 is shown in FIG. 2A). One of the three imaging elements 129 captures an image of the notch (V-shaped notch (not shown)) of the wafer W when the loading disk 121 (disk body 123) holds the wafer W, and the other two Images the periphery of the wafer W. The imaging results of the three imaging elements 129 are supplied to main controller 20. The main controller 20 uses the results of these imagings, for example, by the method disclosed in US Pat. No. 6,624,433 or the like to displace and rotate the wafer W in the X-axis direction and the Y-axis direction (θz). (Rotation) error.

  The ultrasonic speaker 150 is disposed at the center of the bottom surface of the disk main body 123 (see FIG. 2B). The ultrasonic speaker 150 includes a plurality of (in this embodiment, 61) sound pressure sources 151 arranged in a hexagonal lattice. In the present embodiment, each sound pressure source 151 has an acoustic characteristic of generating a sound pressure (acoustic wave) of 100 Pa at 40 kHz, for example. This frequency (40 kHz) is a frequency outside (higher than) the audible band (20 Hz to 20 kHz), and the sound pressure (sound wave) in a high frequency band including the frequency is high in directivity. In addition, a high-frequency band sound pressure source capable of generating a strong sound pressure is employed. As described above, by arranging the plurality of sound pressure sources 151 densely (in the present embodiment, in a hexagonal lattice shape) to constitute one ultrasonic speaker 150, the intensity of sound pressure (sound waves) is increased, and the directivity is increased. Has been further improved.

  The elimination of the distortion of the wafer by the ultrasonic speaker 150, that is, by the vibration of the sound pressure will be described later. In the present embodiment, as an example, the ultrasonic speaker 150 is configured by using the sound pressure source 151 in a high frequency band, but the present invention is not limited to this. For example, a sound pressure source in a frequency band outside the vibration band of several thousand Hz that can affect the drive control of wafer stage WST can be employed.

  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 inline with the exposure apparatus 100 is provided.

  A measurement stage MST is arranged near 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, there is provided a line sensor (not shown) for irradiating the back surface of the wafer W held in the loading disk 121 in a line shape and receiving the reflected light to measure the shape of the wafer W. Is provided. The 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 or an encoder system. The measurement result is supplied to main controller 20.

  The loading unit 120 (the drive unit 122, the air supply unit (not shown), the wafer transfer arm 118, etc.) is controlled by the main controller 20 (see FIG. 3).

  FIG. 3 shows a main configuration of a control system of exposure apparatus 100. The control system is mainly configured by a main controller 20 including a microcomputer (or a workstation) that integrally controls the entire apparatus.

  In exposure apparatus 100 of the present embodiment, sound pressure (ultrasonic waves) is radiated to a wafer mounted on wafer stage WST (wafer holder WH) using ultrasonic speaker 150 constituting loading disk 121, and wafer (Vibration of sound pressure) to eliminate wafer distortion.

  FIG. 4A shows an experimental result that demonstrates that distortion of a wafer can be eliminated by sound pressure excitation. As will be described later, the wafer W is placed on the wafer stage WST (wafer holder WH) using the loading unit 120, and while the wafer W is subjected to sound pressure vibration using the ultrasonic speaker 150, the wafer W is used using the wafer holder WH. Is vacuum-adsorbed. Here, the strain of the wafer is measured using a strain gauge (not shown). However, the strain criterion is not defined in this measurement (ie, the strain gauge is not calibrated). Therefore, the vacuum suction and release of the wafer are repeated a plurality of times, and the true strain is calculated based on the strain of the wafer W measured after the first vacuum suction from the strain measured after the first vacuum suction. (Referred to as residual strain). From FIG. 4A, it can be confirmed that the residual distortion when there is sound pressure excitation is clearly smaller than the residual distortion when there is no sound pressure excitation.

  FIG. 4B shows the results of distortion measured at a plurality of different measurement positions on the wafer. However, the measurement was performed 15 times, and the average is shown. The plurality of measurement positions a to h are shown in FIG. Here, the distortion in each of the X-axis direction and the Y-axis direction is measured at each measurement position. The measurement position and the direction of the measured distortion are specified using a channel (ch). From FIG. 4B, it can be confirmed that, except for some channels, the residual distortion when there is sound pressure excitation is clearly smaller than the residual distortion when there is no sound pressure excitation.

  Therefore, it has been proved that the sound pressure excitation reduces the frictional resistance received from the wafer holder and eliminates the distortion of the wafer. Here, for example, a method of vibrating the wafer using a piezoelectric element or the like is also conceivable. However, contact with the wafer may cause distortion at the contacting portion. On the other hand, when sound pressure is used, since the wafer is vibrated in a non-contact manner, distortion of the wafer can be efficiently eliminated without causing such distortion due to contact.

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

  It is assumed that the loading disk 121 is retracted upward (in the + Z direction) and the wafer stage WST is retracted to a position other than the loading position. It is assumed that the loading disk 121 is in a stopped state.

  Prior to the wafer holding operation, the main controller 20 operates the loading disk 121, that is, supplies a flow of air necessary for holding the wafer W to the plurality of Bernoulli cups 124. Here, main controller 20 measures the temperature of the air ejected from a plurality of Bernoulli cups 124 using temperature sensor 128, and adjusts the temperature of the air to 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. 5A, the wafer W provided with the sensitive layer (resist layer) by the C / D (not shown) is moved by the wafer transfer arm 118 toward the loading position as indicated by a black arrow. Transported in the direction (+ Y direction). When the wafer W is transported to a position directly below the loading disk 121, the main controller 20 drives the loading disk 121 in the direction of a white arrow (-Z direction) as shown in FIG. The lower surface of the disk 121 approaches the surface of the wafer W. Instead of, or together with, 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 approaches the surface of the wafer W to the order of 100 μm, the suction force of the loading disk 121 is applied to the wafer W, and the wafer W is held in non-contact with the loading disk 121. 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. 5C, main controller 20 minutely drives loading disk 121 holding wafer W in the direction of the white arrow (+ Z direction), or alternatively (or together with) this. The wafer transfer arm 118 is minutely driven in the direction (-Z direction) opposite to the white arrow, and the wafer transfer arm 118 that has released the wafer W is retracted in the black arrow direction (-Y direction).

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

  Main controller 20 uses three imaging elements 129 to image the periphery (notch or the like) of wafer W held on loading disk 121. Main controller 20 obtains a displacement of the wafer W in the X-axis direction and the Y-axis direction and a rotation (θz rotation) error from these imaging results.

  As shown in FIG. 6A, main controller 20 moves wafer stage WST to the loading position. Here, main controller 20 positions wafer stage WST at a position and a direction that cancel the above-discussed displacement and rotation error. Alternatively, the position shift 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 directly below loading disk 121, main controller 20 controls three CT pins 140 from inside wafer stage WST via a wafer holder (not shown), as shown in FIG. In the direction of the black arrow (+ Z direction), and their ends contact the back surface of the wafer W held by the loading disk 121 to support (adsorb) the wafer W. Thereby, the movement of the wafer W in the X-axis direction, the Y-axis direction, and the θz direction is further restricted.

  When the wafer W is held by the loading disk 121, its movement in the Z-axis direction, the θx direction, and the θy direction is restricted. When the movements in the axial direction and the θz direction are restricted, as shown in FIG. 6C, main controller 20 drives loading disk 121 in the direction of the outlined arrow (−Z direction). At the same time, the three CT pins 140 are moved in the direction of the black arrow (-Z direction) and housed in wafer stage WST (holder WH). Thereby, as shown in FIG. 7A, wafer W is mounted on wafer stage WST with the movement in the six degrees of freedom direction substantially restricted.

  When wafer W is loaded on wafer stage WST, main controller 20 retracts loading disk 121 in the direction of the outlined arrow (+ Z direction), as shown in FIG. The loading disc 121 is stopped.

  After the evacuation (or at the same time as the evacuation), as shown in FIG. 7C, main controller 20 uses ultrasonic speaker 150 constituting loading disk 121 to place on wafer stage WST (wafer holder WH). A sound pressure (ultrasonic wave) is radiated to the wafer W placed on the wafer W to excite the wafer W with the sound pressure. Thus, as described above, the distortion of the wafer W is eliminated.

  Lastly, main controller 20 activates wafer holder WH to suction-hold wafer W on wafer holder WH (that is, wafer stage WST). Thereby, wafer W is held on wafer stage WST. Then, after the suction holding (or before the suction holding), the emission of the sound pressure from the ultrasonic speaker 150 is stopped.

  Next, 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 W provided with a sensitive layer (resist layer) by C / D (not shown) using wafer unit WST (wafer holder (not shown)) by the above-described procedure. (Not shown)).

  Main controller 20 uses alignment detection system AS to detect an alignment mark provided on the surface of wafer W (attached to a sample shot area on wafer W), and executes alignment measurement (EGA). Thereby, the position of the shot area on the wafer W in the XY plane (the magnification in the scanning direction, the rotation around the optical axis AX, the orthogonality) is determined. The details of the alignment measurement (EGA) are described in, for example, JP-A-6-349705.

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

  In 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 scanning start positions (acceleration). To the start position). Then, main controller 20 relatively drives both stages RST and WST in the Y-axis direction, but in directions opposite to each other. Here, when both the stages RST and WST reach their respective target speeds, the pattern area of the reticle R starts to be illuminated by the illumination light IL, and the scanning exposure is started.

  Main controller 20 controls the 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 the scanning exposure. RST and wafer stage WST are driven synchronously.

  When the reticle R moves in the Y-axis direction, the entire area of the pattern area is illuminated by the 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 direction opposite 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 wafer stage WST to a scanning start position (acceleration start position) for the next shot area (step movement). Then, main controller 20 performs scanning exposure on the next shot area as before. Scanning exposure for the other shot areas is performed similarly. In this way, 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, according to the above-described procedure, the next wafer W provided with the sensitive layer (resist layer) by C / D (not shown) is loaded on wafer stage WST (wafer holder (not shown)). That is, wafer W on wafer stage WST is replaced. Main controller 20 repeats the exposure operation for a new wafer W in the same manner.

  As described in detail above, according to the exposure apparatus 100 of the present embodiment, the sound pressure source (ultrasonic speaker 150) is used to emit sound toward the wafer W placed on the wafer stage WST (wafer holder WH). By radiating pressure (ultrasonic waves), the wafer is vibrated by sound pressure, and the wafer is held by suction using the wafer holder WH. As a result, it is possible to hold the wafer on the wafer holder without causing distortion, and it is possible to maintain high pattern overlay accuracy.

  In the exposure apparatus 100 of the present embodiment, the sound pressure source (ultrasonic speaker 150) is provided on the loading disk 121, but is not limited thereto, and may be configured independently of the loading disk 121. For example, it may be fixed to a frame (not shown) that supports the projection optical system PL (projection unit PU). Further, as long as sound pressure (ultrasonic waves) can be radiated to wafer W mounted on wafer stage WST (wafer holder WH), it may be installed at any place in exposure apparatus 100.

  When the heat generated from the ultrasonic speaker may affect the surroundings, the ultrasonic speaker may be isolated from the surroundings by heat insulation or a temperature control device.

  In exposure apparatus 100 of the present embodiment, a sound pressure source (ultrasonic speaker 150) is provided at the center of the bottom surface of loading disk 121, and a sound pressure source (ultrasonic speaker 150) is provided at the center of wafer W mounted on wafer stage WST (wafer holder WH). Pressure (ultrasonic waves) was emitted. Here, if the vibration due to the sound pressure (ultrasonic wave) is transmitted to the entire wafer, the sound pressure (ultrasonic wave) may be radiated to a narrower area on the wafer, and the end portion is not limited to the center of the wafer. May be radiated. Further, since the sound pressure (ultrasonic waves) in the high frequency band has high directivity, the sound pressure may be emitted not only from above but also obliquely from above, or may be emitted from a position further away from the wafer.

  In addition, in order to eliminate minute distortion of the wafer, in the present embodiment, a sound having a high-order mode having a plurality of nodes (a point where the amplitude of the sound pressure is zero or a minimum, a node of the sound pressure) on the wafer. Pressure (ultrasonic) was used. For example, a high-order mode having at least one node can be adopted in each of the shot regions on the wafer W where the pattern of the reticle R is formed.

  In the exposure apparatus 100 of this embodiment, the loading position for loading the wafer W on 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. Thereby, the throughput can be expected to be improved because the loading / unloading of the wafer W can be performed in parallel with other operations.

  In the above-described embodiment, a case has been described in which the present invention is applied to a dry-type exposure apparatus that exposes a wafer W without the intervention of liquid (water). However, the present invention is not limited to this. As disclosed in Japanese Patent Application No. 99/49504, European Patent Application Publication No. 1,420,298, International Publication No. 2004/055803, and US Patent No. 6,952,253, a projection optical system is disclosed. The present invention can also be applied to an exposure apparatus that forms an immersion space including an optical path of illumination light between the wafer and the wafer, and exposes the wafer with illumination light via the projection optical system and the liquid in the immersion space. . The present invention can also be applied to an immersion exposure apparatus and the like disclosed in, for example, US Patent Application Publication No. 2008/888843.

  Further, 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 is applicable to a stationary exposure apparatus such as a stepper. May be. Further, the present invention can be applied to a step-and-stitch type reduction projection exposure apparatus that synthesizes a shot area and a shot area, a proximity type exposure apparatus, or a mirror projection aligner. 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 be applied to a multi-stage type exposure apparatus having a stage. Further, as disclosed in, for example, US Pat. No. 7,589,822, an exposure apparatus including a measurement stage including a measurement member (for example, a reference mark and / or a sensor) separately from the wafer stage. The present invention can be applied to an apparatus.

  Further, the projection optical system in the exposure apparatus of the above embodiment may be not only a reduction system but also any one of an equal magnification and an enlargement system, and the projection optical system PL may be not only a refraction system but also a reflection system and a catadioptric system. However, the projected image may be either an inverted image or an erect image. Further, the illumination area and the exposure area are rectangular in shape, but are not limited thereto, 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 a KrF excimer laser (output wavelength 248 nm), an F ₂ laser (output wavelength 157 nm), an Ar ₂ laser (output wavelength 126 nm), a Kr ₂ laser ( It is also possible to use a pulse laser light source having an output wavelength of 146 nm or the like, an ultra-high pressure mercury lamp emitting an emission line such as a g-line (wavelength of 436 nm), or an i-line (wavelength of 365 nm). Further, a harmonic generation device of a YAG laser or the like can be used. In addition, as disclosed in, for example, US Pat. No. 7,023,610, a single-wavelength laser beam in the infrared or visible range oscillated from a DFB semiconductor laser or a fiber laser as vacuum ultraviolet light. For example, harmonics amplified by a fiber amplifier doped with erbium (or both erbium and ytterbium) and wavelength-converted to ultraviolet light using a nonlinear optical crystal may be used.

  Further, 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 using EUV (Extreme Ultraviolet) light in a soft X-ray region (for example, a wavelength range 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 through a projection optical system, and one reticle pattern is formed on the wafer by one scan exposure. The present invention can also be applied to an exposure apparatus that double-exposes one shot area almost simultaneously.

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

  The application of the exposure apparatus is not limited to an exposure apparatus for manufacturing semiconductors. For example, an exposure apparatus for a liquid crystal for transferring a liquid crystal display element pattern onto a square glass plate, an organic EL, a thin film magnetic head, an imaging device (CCD, etc.), micromachines, and exposure apparatuses for manufacturing DNA chips, etc. In addition to micro devices such as semiconductor elements, glass substrates or silicon wafers for manufacturing reticles or masks used in light exposure equipment, EUV exposure equipment, X-ray exposure equipment, electron beam exposure equipment, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern to a substrate.

  For an electronic device such as a semiconductor element, a step of designing the function and performance of the device, a step of manufacturing a reticle based on this design step, a step of manufacturing a wafer from a silicon material, and an exposure apparatus (pattern forming apparatus) of the above-described embodiment ) And a lithography step of transferring a pattern of a mask (reticle) to a wafer by the exposure method, a development step of developing the exposed wafer, an etching step of etching away portions of the exposed member other than the portion where the resist remains, It is manufactured through a resist removing step of removing unnecessary resist after etching, a device assembling step (including a dicing step, a bonding step, a package step), an inspection step, and the like. In this case, in the lithography step, the above-described exposure method is performed using the exposure apparatus of the above-described embodiment, and a device pattern is formed on the wafer, so that a highly integrated device can be manufactured with high productivity.

  Reference Signs List 20: Main controller, 100: Exposure device, 118: Wafer transfer arm, 120: Loading unit, 121: Loading disk, 124: Bernoulli cup, 125: Piping, 128: Temperature sensor, 129: Image sensor, 140: CT pin , 150: ultrasonic speaker, PL: projection optical system, PU: projection unit, W: wafer, WH: wafer holder, WST: wafer stage.

Claims (18)

A holding device for holding an object,
A holding member capable of adsorbing and holding the placed object,
After the object is placed on the holding member and before the holding member adsorbs the object, a sound pressure source that radiates sound pressure to the object placed on the holding member ,
A drive device that changes the position of the sound pressure source with respect to the holding member after the object is placed on the holding member and before the holding member adsorbs the object ,
A holding device comprising:   2. The holding device according to claim 1, wherein the sound pressure is emitted to the object placed on the holding member in parallel with a change in the position of the sound pressure source with respect to the holding member. 3. The sound pressure source, the holding apparatus according to claim 1 or 2 for radiating sound pressure from obliquely upward placed on said object to said retaining member. The holding device according to any one of claims 1 to 3 , wherein the sound pressure source emits the sound pressure from a position obliquely upward to the center of the object. The holding device according to any one of claims 1 to 4 , wherein the sound pressure source radiates the sound pressure from an obliquely upward position to an end of the object. The object is a plate-shaped member having a first surface at least partially in contact with the holding member, and a second surface opposite to the first surface, wherein the sound pressure is The holding device according to any one of claims 1 to 5 , which is radiated toward the second surface. The holding device according to any one of claims 1 to 6 , wherein the sound pressure source is an ultrasonic speaker. The holding device according to any one of claims 1 to 7 , wherein the sound pressure has directivity. An exposure apparatus that forms a pattern on an object by irradiating an energy beam,
A holding device according to any one of claims 1 to 8 ,
An exposure apparatus that irradiates the object held by the holding member with the energy beam. An optical system that irradiates the energy beam, and a frame that supports the optical system,
The exposure apparatus according to claim 9 , wherein the sound pressure source is provided on the frame. A holding method for holding an object,
Placing the object on a holding member capable of holding the object by suction ,
Radiating a sound pressure generated by a sound pressure source to the object placed on the holding member after the object is placed on the holding member and before the holding member adsorbs the object. When,
After the object is placed on the holding member and before the holding member adsorbs the object , changing the position of the sound pressure source with respect to the holding member,
A holding method including: The holding method according to claim 11 , wherein the sound pressure is emitted to the object placed on the holding member in parallel with a change in the position of the sound pressure source with respect to the holding member. The holding method according to claim 11 , wherein the sound pressure source emits a sound pressure to the object placed on the holding member from obliquely above. The object is a plate-shaped member having a first surface at least partially in contact with the holding member, and a second surface opposite to the first surface, wherein the sound pressure is The holding method according to any one of claims 11 to 13 , wherein the light is emitted toward the second surface. The holding method according to any one of claims 11 to 14 , wherein the sound pressure source is an ultrasonic speaker. The holding method according to any one of claims 11 to 15 , wherein the sound pressure has directivity. An exposure method for irradiating an energy beam to form a pattern on an object,
An exposure method that irradiates the energy beam on the object held by the holding member using the holding method according to any one of claims 11 to 16 . A device manufacturing method including a lithography step,
The lithography step
Forming a pattern on an object using the exposure method according to claim 17 ;
Developing the object on which the pattern is formed;
A device manufacturing method including:

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