JP2007093546A - Encoder system, stage device, and exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately measure a position in an encoder system, a stage device and exposure apparatus. <P>SOLUTION: The exposure apparatus 100 is provided with the encoder system 16 having encoders 17<SB>Y1</SB>, 17<SB>Y2</SB>and 17<SB>X</SB>in order to measure positional information of a reticle stage RST. A laser probe generated from probe sections 19<SB>Y1</SB>, 19<SB>Y2</SB>and 19<SB>X</SB>of the encoders 17<SB>Y1</SB>, 17<SB>Y2</SB>and 17<SB>X</SB>oscillates along the arrangement direction of the pattern on a scale 18<SB>1</SB>, and outputs a signal that includes the positional information and is modulated by oscillation of the probe. The phase of the modulated signal is detected with higher harmonics of oscillation frequency, and the positional information of the reticle stage RST is detected based on the detection result. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an encoder system, a stage apparatus, and an exposure apparatus, and more specifically, an encoder system that detects a pattern arranged in a measurement direction and measures a displacement of an object to be measured, a stage apparatus including the encoder system, and the The present invention relates to an exposure apparatus including a stage apparatus.

  Conventionally, an exposure apparatus used in a semiconductor manufacturing process includes a stage for holding a semiconductor wafer and a stage for holding a mask on which a circuit pattern or the like is formed. During exposure, the position of the stage is constantly measured by a measuring device, and the position of the stage is controlled based on the measurement result, so that the circuit pattern on the mask is accurately transferred onto the semiconductor wafer. Will be able to.

  Recently, in order to accurately transfer a finer circuit pattern, the demand for the position control performance of the stage has become strict. In order to meet this requirement, several high-resolution encoders that detect stage position information have been proposed (see, for example, Patent Documents 1 and 2).

  These encoders include a scale and a probe, and are configured to detect the relative position of the probe with respect to the scale attached to the stage. The scale has a pattern arranged in at least a one-dimensional direction, and is attached to the stage so that the arrangement direction of the pattern is along the measurement axis. Further, the probe is installed on the scale so as to vibrate along the arrangement direction of the pattern. This probe oscillates on the scale in the pattern arrangement direction, and outputs a signal containing information on the relative position of the scale with the vibration center of the probe as the reference position. It is modulated by a periodic drive signal for generating the signal.

  Therefore, the encoder further includes a detection device that detects the relative position between the vibration center of the probe and the scale based on the signal output from the probe. In this detection device, a harmonic signal of a probe vibration drive signal is generated by a frequency synthesizer, and the drive signal that vibrates the probe is compared with the signal output from the probe to determine the relative position of the probe and the scale. Looking for.

  In an encoder detection apparatus, from the viewpoint of cost and the like, the frequency synthesizer and the like are generally configured by a sample value system. In order to generate the harmonics of the drive signal without any inconvenience in the sample value system, it is necessary to set the calculation cycle to an integral fraction of the cycle of the original frequency (drive signal).

  When using such an encoder for detection of stage position information, this encoder is installed at several different locations on the stage, and the encoder outputs are acquired as the displacement of the stage at that location, and these are acquired. A comprehensive calculation using the result is performed to calculate the position coordinates of the stage. The detection of the position coordinates of the stage is performed at every sampling period, but the measurement values of the encoders used for calculating the position coordinates of the stage at each sampling time must be detected at the same timing. . If this timing is shifted, for example, if the stage is moving at a moving speed V and the output timing between two encoders with the same measurement direction is different by t seconds, the stage rotates by V × t. There is a risk that erroneous recognition of the position of the stage may occur.

  Therefore, it is necessary for the detection device in each encoder to have the same calculation cycle and to precisely align the delay time (data age) of the output signal. However, as described above, there is a restriction that the calculation cycle of the detection device of each encoder must be an integral multiple of the cycle of the probe drive signal, and the frequency of the drive signal that vibrates the probe for each encoder varies. The calculation cycle of the detection device cannot be made the same, and the output timing between the encoders is different.

Special Table 2000-511634 US Pat. No. 6,369,686

  From the first viewpoint, the present invention detects a first scale having a pattern arranged in a first direction, and a pattern of the first scale, and is modulated with a first periodic signal in the first direction. A first encoder comprising: a first probe that outputs an output signal; and a detection device that detects relative position information of the first scale and the first probe based on the output signal output from the first probe; A second scale having a pattern arranged in a second direction; a second probe for detecting the pattern of the second scale and outputting an output signal modulated with a second periodic signal in the second direction; A second encoder comprising: a detection device that detects relative position information between the second scale and the second probe based on an output signal output from the second probe; Periodic signal and the second periodic signal and a synchronization device for synchronizing; is an encoder system comprising a.

  According to this, since the synchronization device that synchronizes the first periodic signal that is the driving signal of the vibration of the first probe and the second periodic signal that is the driving signal of the vibration of the second probe is provided, Detection of relative position information between the first scale and the first probe and detection of relative position information between the second scale and the second probe can be performed using synchronized signals. For this reason, the calculation cycle of the detection apparatus can be made the same between the first and second encoders.

  According to a second aspect of the present invention, in a stage apparatus including a stage that moves in a predetermined direction and a measurement apparatus that measures the position of the stage in the predetermined direction, the encoder system of the present invention is used as the measurement apparatus. The stage apparatus is characterized in that the first encoder and the second encoder constituting the encoder system are arranged at a predetermined interval with respect to a direction orthogonal to the predetermined direction. In such a case, since the two encoders that measure the positional information in the predetermined direction constituting the encoder system of the present invention are arranged at a predetermined interval in a direction orthogonal to the predetermined direction, the outputs of the two encoders The stage position information in the predetermined direction can be detected with high accuracy based on the above, and the rotation amount of the stage in the two-dimensional plane including the predetermined direction and the direction orthogonal to the predetermined direction can be determined. Can also be detected.

  According to a third aspect of the present invention, in a stage apparatus including a stage and a measurement apparatus that measures the position of the stage, the measurement apparatus includes the encoder system of the present invention, the first encoder, The second encoder measures the position of the stage in a predetermined direction, and the third encoder measures the position in a direction orthogonal to the predetermined direction. In such a case, based on the position information of the first, second, and third encoders constituting the encoder system of the present invention, not only the predetermined direction and the rotation amount of the stage, but also the stage orthogonal to the predetermined direction. Position information can also be detected.

  According to a fourth aspect of the present invention, there is provided an exposure apparatus for transferring a predetermined pattern onto a photosensitive object, wherein either one of the photosensitive object and a member on which the predetermined pattern is formed is placed on a stage. An exposure apparatus comprising: a stage apparatus according to the present invention; and a beam source for irradiating the photosensitive object with an energy beam. In such a case, since exposure is performed using an object placed on the stage apparatus of the present invention, highly accurate exposure can be realized.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 schematically shows a configuration of an exposure apparatus 100 that preferably includes an encoder system and a stage apparatus according to an embodiment of the present invention. This exposure apparatus 100 is a step-and-scan projection exposure apparatus in which the Y-axis direction is the scan direction. The exposure apparatus 100 includes an illumination system 10, a reticle stage RST, an encoder system 16 that measures position information thereof, a projection optical system PL, a wafer stage WST, and a control system thereof (see FIG. 3). It consists of

  The illumination system 10 emits, for example, coherent illumination light (exposure light) IL in the ultraviolet region or vacuum ultraviolet region toward the reticle stage RST.

  The reticle stage RST is a stage that holds a reticle on which a circuit pattern or the like to be transferred is formed. The reticle is sucked and held near the opening 32 provided at the center of the reticle stage RST, for example, by vacuum suction. The reticle stage RST is two-dimensionally (X-axis) in an XY plane perpendicular to the optical axis AX of the projection optical system PL by a reticle stage drive unit 21 (not shown in FIG. 1, see FIG. 3) including a linear motor or the like. Direction, the Y-axis direction, and the rotation direction (θz direction) about the Z-axis orthogonal to the XY plane, and can be driven at the scanning speed specified in the Y-axis direction.

Position information in the XY plane of reticle stage RST is detected by encoder system 16 with a resolution of 0.1 nm or less. The encoder system 16 includes three encoders 17 _Y1 , 17 _Y2 and 17 _X. Encoders 17 _Y1 and 17 _Y2 detect displacement of reticle stage RST in the Y-axis direction, and encoder 17 _X detects displacement of reticle stage RST in the X-axis direction.

The encoder 17 _Y1 includes a scale 18 ₁ extending in the Y-axis direction on the reticle stage RST, and a probe portion 19 _Y1 for emitting vibratable beam probes in the Y-axis direction. A reflective diffraction grating (grating 1 in FIG. 2) having periodicity in the Y-axis direction is formed on the scale 18 ₁ . As shown in FIG. 2, this diffraction grating is a concavo-convex surface type diffraction grating, and its surface shape is a sine wave shape. The pitch (cycle) is the same in all sections.

FIG. 2 schematically shows the configuration of the probe unit 19 _Y1 . As shown in FIG. 2, the probe unit 19 _Y1 includes a laser diode 3, a collimator lens 4, a beam splitter 6, an objective lens 7, a focus lens 8, and an optical sensor 9. The objective lens 7 is connected to the driving device 11 and is configured to vibrate in the Y-axis direction.

A laser beam (wavelength is 640 nm, for example) emitted from the laser diode 3 is collimated by the collimator lens 4, passes through the beam splitter 6, and is condensed on the grating 1 on the scale 18 ₁ by the objective lens 7. The The drive device 11 generates a sine wave voltage (frequency is, for example, 1.5 KHz) according to the drive signal D input from the outside, and a piezoelectric element provided inside vibrates the objective lens 7 in the Y-axis direction according to the sine wave voltage. ing. This vibration realizes beam deflection, and the laser beam vibrates in the Y-axis direction on the grating 1 on the scale 18 _Y1 . A function representing the fluctuation of the sine wave voltage is represented by r × sin ωt. r is the amplitude of vibration, ω is the vibration angular frequency, and t is time.

The laser beam reflected on the grating 1 passes through the objective lens 7, is bent by the beam splitter 6, and is received by the optical sensor 9 via the focus lens 8. A signal received from the optical sensor 9 is sent to a detection device 50 ₁ described later.

Thus, the probe unit 19 _Y1 outputs a laser beam toward the scale 18 _1, the laser beam reflected on the grating 1 of the scale 18 ₁ (beam probe) and received by the optical sensor 9, on the light receiving result The corresponding signal is output. The probe unit 19 _Y1 vibrates the beam probe in the Y-axis direction at an angular frequency ω. Therefore, the signal output from the probe unit 19 _Y1 is a signal including the signal component of the spatial angular frequency ω ′ of the diffraction grating on the scale 18 ₁ and the signal component of the vibration angular frequency ω of the beam probe. Yes. In other words, this output signal is a modulation signal obtained by modulating the signal of the spatial angular frequency ω ′ of the diffraction grating on the scale 18 _{1 with} the signal of the vibration angular frequency ω of the beam probe.

The encoder 17 _Y2 includes a scale 18 ₂ extending in the Y-axis direction on the reticle stage RST, and a probe portion 19 _Y2 for emitting vibratable beam probes in the Y-axis direction. A two-dimensional diffraction grating having periodicity in the X and Y axis directions is formed on the scale 18 ₂ . This diffraction grating is also concavo-convex, and its surface shape is the same sine wave shape as the scale 18 _{1 in} both the X-axis direction and the Y-axis direction, and the pitches in the X-axis direction and the Y-axis direction are also the scale 18 ₁ . The same.

The configuration of the probe unit 19 _Y2 is the same as the configuration of the probe unit 19 _Y1 in FIG. Probe unit 19 _Y2 is toward the scale 18 ₂ outputs a laser beam (beam probe) receives the reflected beam on the grating 1 of the scale 18 ₂ by the optical sensor 9, and outputs a signal corresponding to the received light results is doing. The probe unit 19 _Y2 vibrates the beam probe in the Y-axis direction, like the probe unit 19 _Y1 . For this reason, the signal output from the probe unit 19 _Y2 is also a modulation signal obtained by modulating the signal based on the spatial angular frequency ω ′ of the diffraction grating on the scale 18 ₂ by the vibration (angular frequency ω) of the laser beam. Yes.

Note that the distance in the X-axis direction between the vibration center of the beam probe in the encoder 17 _Y1 and the vibration center of the beam probe in the encoder 17 _Y2 is L, and the X position of these midpoints and the light of the projection optical system PL It is defined so that the X position of the axis AX coincides.

The encoder 17 _X includes a probe unit 19 _X. Structure of the probe unit 19 _X is the same as the structure of the probe unit 19 _Y1, probe unit 19 _X outputs a laser beam (beam probe) toward the scale 18 _2, the light reflected beams scale 18 ₂ The sensor 9 receives light and outputs a signal corresponding to the light reception result. The probe unit 19 _X vibrates this beam probe in the X-axis direction. For this reason, the signal output from the probe unit 19 _X is also the signal of the spatial angular frequency in the X axis direction of the grating 1 on the scale 18 ₂ (also referred to as ω ′), and the vibration of the laser beam (angular frequency ω). The modulated signal is modulated by. Thus, in this embodiment, the scale 18 ₂ is a two-dimensional diffraction grating, and the scale 18 ₂ is shared between the encoders 17 _Y2 and 17 _X.

Note that the Y position of the vibration center of the beam probe in the encoders 17 _Y1 and 17 _Y2 is defined to be the same as the Y position of the optical axis AX of the projection optical system PL.

Note that the configurations of the encoders 17 _Y1 , 17 _Y2 , and 17 _X are disclosed in Japanese Translation of PCT International Publication No. 2000-511634 or US Pat. No. 6,369,686, and a detailed description thereof will be omitted.

FIG. 3 is a block diagram showing a schematic configuration of the encoder system 16. As shown in FIG. 3, the encoder system 16 includes a synchronization circuit 51 in addition to the encoders 17 _Y1 , 17 _Y2 , and 17 _X described above.

The synchronization circuit 51 outputs a drive signal D corresponding to the phase ωt and the amplitude r of the drive voltage that vibrates the objective lens 7 of the probe units 19 _Y1 , 19 _Y2 , and 19 _X of each encoder. The drive signal D includes information regarding the phase ωt and the amplitude r of a predetermined sine wave. In the probe units 19 _Y1 , 19 _Y2 , and 19 _X , the drive signal D is input to the drive device 11. As a result, the angular frequencies ω of the vibrations of the beam probes in the encoders 19 _Y1 , 19 _Y2 , 19 _X are the same, and the phase difference is zero. As shown in FIG. 3, signals output from the probe units 19 _Y1 , 19 _Y2 , and 19 _X are sent to the corresponding detection devices 50 ₁ , 50 ₂ , and 50 ₃ , respectively. As described above, this signal is a signal modulated by the oscillation of the beam probe.

Various configurations are possible for the detection devices 50 ₁ , 50 ₂ , and 50 ₃ , and FIG. 4 is a block diagram showing a general configuration of the detection device 50 ₁ . The detection device 50 ₁ includes a filter 91, a frequency synthesizer 92, multipliers 93 ₁ and 93 ₂ , a phase detector 94, an amplitude detector 95, and a distance calculator 96.

The signal output from the probe unit 19 _Y1 is input to the filter 91. The filter 91 removes the harmonic component of this signal. On the other hand, the frequency synthesizer 92 generates a periodic signal (vibration angular frequency ω, amplitude r) corresponding to the oscillation of the beam probe based on the drive signal D input from the synchronization device 51. The output of the filter 91 and the periodic signal are multiplied by multipliers 93 ₁ and 93 ₂ and input to the phase detector 94 and the amplitude detector 95, respectively. The phase detector 94 detects the phase of the output of the filter 91 corresponding to the frequency of the periodic signal output from the frequency synthesizer 92, and the amplitude detector 95 detects the amplitude of the output of the filter 91 corresponding to the periodic signal. Is done. The distance calculation unit 96, based on the detected phase and amplitude, the distance of the oscillation center of the beam probe from the top of the scale 18 ₁ (peaks) are calculated.

Note that the configuration of the detection apparatus 50 ₁ is disclosed in JP-T-2000-511634 or US Pat. No. 6,369,686, and a detailed description thereof will be omitted.

The configuration of the detection device 50 ₁ is not limited to that shown in FIG. In particular, if the amplitude r of the beam probe oscillation is set appropriately, the apparatus configuration can be simplified. FIG. 5 shows another detailed configuration example of the detection apparatus 50 ₁ in such a case. As shown in FIG. 5, the detection device 50 ₁ includes a filter 61, a frequency synthesizer 62, multipliers 63 ₁ and 63 ₂ , an adder 64, a loop filter 65, an integrator 66, and an adder 67. ₁ and 67 ₂ and sinusoidal function generators 68 ₁ and 68 ₂ .

The signal output from the probe unit 19 _Y1 is input to the filter 61. The filter 61 removes harmonic components of this signal.

On the other hand, the drive signal D output from the synchronization circuit 51 is input to the frequency synthesizer 62. The frequency synthesizer 62 generates and outputs a phase signal 2ωt that is a second harmonic of the drive signal D (phase ωt) and a phase signal 3ωt that is a third harmonic of the drive signal D (phase ωt). The second harmonic phase signal 2ωt is input to the adder 67 ₁ , and the third harmonic drive signal 3ωt is input to the adder 67 ₂ . The adder 67 ₁ adds and outputs a second harmonic phase signal 2ωt and estimated position information ω′X ₀ described later, respectively. The adder 67 ₂ outputs a third harmonic phase signal 3ωt and estimated later described. The position information ω′X ₀ is added and output.

The output of the adder 67 ₁ is input to the sine wave generator 68 _1, and the output of the adder 67 ₂ is input to the sine wave generator 68 ₂ . On the other hand, are driven signal D input to the sine wave generator 68 _1. The sine wave generator 68 ₁ generates and outputs a signal represented by the following expression based on the phase of the second harmonic (2ωt + ω′X ₀ ) and the amplitude r included in the drive signal D.

ここで、Ｊ_n（ｒω’）（ｎ＝０、１、２、３、…）は、ｎ次の第一種ベッセル関数である。また、Ｘ₀は、スケールの峰（凸部の頂点）からプローブの振動中心までの距離を意味する。特表２０００−５１１６３４号公報に開示されるように、プローブ部１７_Y1から出力される信号、すなわち、本実施形態における光センサ９で受光された光強度に相当する信号は、ビームプローブ発振により変調された信号であり、その信号は、時間ｔに関してベッセル級数展開することができる。したがって、上記式（１）で示される信号を、後述するように、フィルタ６１の出力と掛け合わせることにより、上記式（１）に含まれる信号と、ビームプローブの振動角周波数ωの２倍の周波数の成分との位相差を抽出することが可能となる。

Here, J _n (rω ′) (n = 0, 1, 2, 3,...) Is an nth-order first-type Bessel function. X ₀ means the distance from the peak of the scale (the apex of the convex portion) to the vibration center of the probe. As disclosed in JP 2000-511634 A, a signal output from the probe unit 17 _Y1 , that is, a signal corresponding to the light intensity received by the optical sensor 9 in the present embodiment, is modulated by beam probe oscillation. The signal can be expanded in Bessel series with respect to time t. Therefore, by multiplying the signal represented by the above equation (1) with the output of the filter 61 as described later, the signal included in the above equation (1) and twice the vibration angular frequency ω of the beam probe are obtained. It becomes possible to extract the phase difference from the frequency component.

On the other hand, also the sine wave generator 68 _2, the drive signal D is input. The sine wave generator 68 ₂ generates and outputs a signal represented by the following expression based on the phase of the third harmonic wave (3ωt + ω′X ₀ ) and the amplitude r included in the drive signal D.

正弦波発生器６８₁から出力された信号は、フィルタ６１の出力と乗算器６３₁で掛け合わせられ、正弦波発生器６８₂から出力された信号は、フィルタ６１の出力と乗算器６３₂で掛け合わせられる。乗算器６３₁、６３₂の出力信号は、加算器６４で加算された後、ループフィルタ６５に入力され、高周波成分が除去される。

The signal output from the sine wave generator 68 ₁ is multiplied by the output of the filter 61 by the multiplier 63 ₁ , and the signal output from the sine wave generator 68 _{2 is} output by the output of the filter 61 and the multiplier 63 ₂ . Multiply. The output signals of the multipliers 63 ₁ and 63 ₂ are added by the adder 64 and then input to the loop filter 65 to remove high frequency components.

The output of the loop filter 65 is the phase in space corresponding to the estimated relative position of the vibration center of the beam probe with respect to the peak of the grating 1 of the scale 18 ₁ (the apex of the convex portion) and the actual relative position of the vibration center. The value corresponds to the phase difference of the corresponding phase. This value is input to the integrator 66. Since the output of the integrator 66 (that is, ω′X ₀ ) is added to the second and third harmonic signals by the adders 67 ₁ and 67 ₂ as described above, a closed loop is formed in the detection device 50 ₁ . The phase difference between the phase at the estimated position of the vibration center of the beam probe and the phase at the actual position is kept at 0, and the phase ω′X of the vibration center of the beam probe with respect to the peak of the grating 1 (the apex of the convex portion) ₀ is detected with high accuracy. Signal corresponding to the phase difference is input to the converter 70, is converted to the estimated position X _0. The converter 70 calculates the displacement amount of the reticle stage RST in the Y-axis direction based on the estimated position and the count value held inside. The displacement amount is sent to the stage controller 39 as a detection result of the encoder 17 _Y1 .

Note that the principle and circuit configuration of signal detection in the detection apparatus 50 ₁ are disclosed in detail in Japanese Patent Publication No. 2000-511634, US Pat. No. 6,369,686, and the like, and thus detailed description thereof is omitted. Also, these publications, various modifications of the configuration of the detection device 50 ₁ are disclosed, they are those capable adopted as a circuit configuration of the detection device 50 _1.

The configuration of the detection devices 50 ₂ and 50 ₃ is the same as that of the detection device 50 _{1. The} detection device 50 ₂ detects the Y displacement of the reticle stage RST, and the detection device 50 ₃ detects the X displacement of the reticle stage RST. To do. Outputs of the detection devices 50 ₂ and 50 ₃ are sent to the stage control device 39.

The detection devices 50 ₁ , 50 ₂ , and 50 ₃ are configured by a sample value system, and a series of digital calculations are performed at a predetermined calculation cycle (sampling cycle) Δt. As shown in FIG. 6A, in the detection devices 50 ₁ , 50 ₂ , and 50 ₃ , the ratio between the calculation period Δt and the vibration period 2π / ω of the probe oscillation drive signal is an integer ratio. Is set.

As described above, the measurement values of the encoders 17 _Y1 and 17 _Y2 correspond to the Y displacement of the reticle stage RST, and the measurement value of the encoder 17 _X corresponds to the X displacement of the reticle stage RST. Further, the X position of the midpoint of the vibration center of the beam probe of the encoders 17 _Y1 and 17 _Y2 and the X position of the optical axis AX of the projection optical system PL coincide with each other, and the vibration of the beam probe of the encoders 17 _Y1 and 17 _Y2 The center Y position coincides with the Y position of the optical axis AX of the projection optical system PL. Therefore, the stage control device 39 calculates the average value of the measurement values of the encoders 17 _Y1 and 17 _Y2 as the Y position of the reticle stage RST, and calculates the distance between the measurement lines and the measurement values of the encoders 17 _Y1 and 17 _Y2. Based on the above, the rotation amount of the reticle stage RST about the Z axis θz is calculated, and the measurement value of the encoder 17 _X is set as the X position of the reticle stage RST.

The stage control device 39 acquires measurement values of the encoders 17 _X , 17 _Y1 , and 17 _Y2 of the encoder system 16 at a predetermined cycle, calculates position information of X, Y, and θz of the reticle stage RST, and the position information. Based on the above, the position of the reticle stage RST is controlled via the reticle stage drive unit 21.

  Projection optical system PL is arranged below reticle stage RST in FIG. 1, and the direction of optical axis AX is the Z-axis direction. As the projection optical system PL, a birefringent optical system that is telecentric on both sides and has a predetermined reduction magnification (for example, 1/5 or 1/4) is used. Therefore, when the illumination area of the reticle R is illuminated by the illumination light IL from the illumination system 10, a reduced image (partial inverted image) of the illumination area of the circuit pattern of the reticle R is formed on the wafer W via the projection optical system PL. Are projected onto a projection area in the field of view of the projection optical system PL conjugate to the illumination area, and transferred onto the resist layer on the surface of the wafer W.

  Wafer stage WST is arranged on a base (not shown) below projection optical system PL in FIG. 1, and is, for example, a Y-axis by wafer stage drive unit 24 (not shown in FIG. 1, see FIG. 3) including a linear motor or the like. Drive with a predetermined stroke in the direction and the X-axis direction orthogonal thereto, the Z-axis direction, the θx direction (the rotation direction around the X axis), the θy direction (the rotation direction around the Y axis), and the θz direction (around the Z axis) In the rotation direction). A wafer holder (not shown) is placed on wafer stage WST, and wafer W is fixed on the wafer holder by, for example, vacuum suction.

  The position of wafer stage WST in the XY plane is always detected by a laser interferometer 38 (see FIG. 3) with a resolution of about 0.5 to 1 nm, for example. Position information (or speed information) of wafer stage WST on the stage coordinate system is supplied to stage control device 39. The stage controller 39 controls the wafer stage WST via the wafer stage driving unit 24 based on the position information (or speed information) of the wafer stage WST.

  The stage control device 39 is constructed with a control system for controlling the positions of both stages WST and RST. This control system is configured so that the stages WST and RST can be driven independently or in synchronization with each other. For example, when loading a reticle onto reticle stage RST, reticle stage RST can operate independently from wafer stage WST. When performing loading of wafer W, wafer alignment, etc., wafer Stage WST can operate independently of reticle stage RST. When performing scanning exposure, both stages WST, RST are set so that reticle stage RST also moves at a predetermined scanning speed in synchronization with movement of wafer stage WST in the Y-axis direction at a predetermined scanning speed. Synchronous control is performed.

  In exposure apparatus 100, after a reticle is loaded on reticle stage RST and wafer W is loaded on wafer stage WST, the alignment between the reticle and wafer W is performed by a predetermined method, and scanning is performed on the reticle. The circuit pattern and the like are transferred onto the wafer W. In these series of processes, the position information of the reticle stage RST in the XY plane is measured by the encoder system 16 having a resolution of about 0.1 nm, so that the reticle loading and the alignment between the reticle and the wafer W are accurately performed. As a result, the pattern on the reticle can be transferred onto the wafer W with high accuracy.

Further, the beam probe oscillation of the encoders 17 _Y1 , 17 _Y2 , and 17 _X is performed using the drive signal D from the synchronization device 51 as the original frequency, the oscillation period is the same, and the phase difference is also set to zero. Yes. As a result, the sampling timings in the detectors 50 ₁ , 50 ₂ , 50 ₃ of the encoders 17 _Y1 , 17 _Y2 , 17 _X can be made the same. As a result, the encoders 17 _Y1 , 17 _Y2 and 17 _X can output information on the Y displacement and X displacement of the reticle stage RST detected simultaneously. The stage control device 19 can perform position control of the reticle stage RST without erroneously recognizing position information of the reticle stage RST based on the Y displacement and X displacement of the reticle stage RST detected simultaneously.

As described in detail above, according to this embodiment, a drive signal of the beam probe oscillation of the probe portion 19Y ₁ of the encoder 17 _Y1, and a drive signal of the vibration of the probe portion 19Y ₂ beams probe the encoder 17 _Y2 Since the synchronizing device 51 for synchronization is provided, the detection of the relative position information of the scale 18 ₁ and the probe 19 _Y1 and the detection of the relative position information of the scale 18 ₂ and the probe 19 _Y2 are performed using the synchronized signals. Can be done. For this reason, the calculation cycles of the detection devices 50 ₁ and 50 ₂ can be made the same by the encoders 19 _Y1 and 19 _Y2 . As a result, the reticle stage RST can be controlled with high accuracy without erroneously recognizing the displacement of the reticle stage RST in the Y-axis direction.

That is, in this embodiment, the synchronization device 51 uses a signal for driving the vibration of the beam probe of the probe unit 19 _Y1 and a signal for driving the vibration of the beam probe of the probe unit 19 _Y2 as the synchronization device 51. These are based on the drive signal D output from, the vibration angular frequency ω is the same, the phase difference is kept at 0, and the vibrations of the beam probes in the two encoders 17 _Y1 and 17 _Y2 are completely synchronized. In this way, the calculation cycles of the detection devices 50 ₁ and 50 ₂ can be made the same, the detection timing of the Y displacement of the reticle stage RST can be made simultaneous, and the circuits of the detection devices 50 ₁ and 50 ₂ can be made simultaneously. The configuration and the like can be the same, and the design and manufacture of the device is facilitated.

Incidentally, the vibration of the two probe portions 19 _Y1, 19 _Y2 beam probe, not completely necessary to synchronize, synchronizer 51 includes a vibration angular frequency of the beam probe of the probe unit 19 _Y1, beam probe portion 19 _Y1 The ratio with the vibration angular frequency of the probe may be an integer ratio. FIG. 6B shows a sample value system in the case where the vibration angular frequency of the beam probe of the probe unit 19 _Y1 is ω1, the vibration angular frequency of the beam probe of the probe unit 19 _Y2 is ω2, and 2ω1 = ω2. The time chart is shown. Even in this case, as shown in FIG. 6B, the calculation cycles of the detection devices 50 ₁ and 50 ₂ can be made equal by Δt. That is, if the ratio of the oscillation frequencies of the beam probes of the encoders 19 _Y1 and 19 _Y2 is an integer, the calculation cycle Δt can be set to be the same, and the output timings of the detection signals in the encoders 19 _Y1 and 19 _Y2 are completely synchronized. It is possible.

Further, according to this embodiment, the probe unit 19 _Y1 includes a driving device 11 for driving the objective lens 7 in order to oscillate the laser beam to be irradiated to the scale 18 ₁ in the Y-axis direction, the probe unit 19 _Y2 is The driving device 11 drives the objective lens 7 to vibrate the laser beam applied to the scale 18 ₂ in the Y-axis direction. Then, the driving signal D for vibrating the driving device 11 configuring the probe unit 19 _Y1 and the driving signal D for vibrating the driving device 11 configuring the probe unit 19 _Y2 are output from the synchronization device 51. Signal. However, the present invention is not limited to this, and the drive signals input to each probe unit may have a certain phase difference. FIG. 6C shows a time chart when a phase difference Δθ is generated between the drive signal of the probe unit 19 _{Y1 and} the drive signal of the probe unit 19 _Y2 . In this case, the position information of the reticle stage RST may be calculated by the stage controller 39 with the output of the probe unit 19 _Y2 delayed by Δθ.

The configuration of the encoder system 16 is not limited to that of the above embodiment. FIG. 7 schematically shows a configuration of an encoder system 16 ′ that can be used in place of the encoder system 16. As shown in FIG. 7, the encoder system 16 ′ includes a laser diode 3, a collimator lens 4, a branching device 71, and probe units 19 _Y1 ′, 19 _Y2 ′, 19 _X ′.

The probe portions 19 _Y1 ′, 19 _Y2 ′, and 19 _X ′ are substantially the same as the probe portions 19 _Y1 , 19 _Y2 , and 19 _X except that the laser diode 3, the collimator lens 4, and the driving device 11 are not provided. It has become.

  The laser diode 3 is connected to the driving device 11 and can vibrate in the Y-axis direction. The laser beam emitted from the laser diode 3 is converted into parallel light by the collimator lens 4.

The branching device 71 includes half mirrors 74 and 75 and mirrors 76 and 77. The beam reflected by the half mirror 74 is reflected by the mirror 76 and enters the probe portion 19 _Y1 ′. On the other hand, the beam transmitted through the half mirror 74 proceeds to the half mirror 75. The beam transmitted through the half mirror 75 enters the probe unit 19 _Y2 ′, and the beam reflected by the half mirror 75 is reflected by several mirrors (not shown) and finally reflected by the mirror 76, and the probe unit 19. Incident on _X '.

That is, the branching device 71 distributes and supplies the laser beam emitted from the laser diode 3 vibrated by the driving device 11 and passing through the collimator lens 4 to the probes 19 _Y1 ′, 19 _Y2 ′, and 19 _X ′. For the laser beam incident on the probe 19 _X ′, several optical systems (not shown) are set in the branching device 71 so that the vibration direction is the X-axis direction.

Probe 19 _Y1 'is a state where a laser beam supplied from the branching unit 71 is vibrated in the Y-axis direction is irradiated to the grating 1 of the scale 18 _1. The probe 19 _Y2 ′ irradiates the grating 1 of the scale 18 _{2 with} the laser beam supplied from the branching device 71 oscillated in the Y-axis direction. The probe 19 _X ′ irradiates the grating 1 of the scale 18 _{2 with} the laser beam supplied from the branching device 71 oscillated in the X-axis direction.

In this way, if the light source is shared by each probe unit and the light source itself is vibrated, the signal output from each encoder is modulated in the same way, so the phase of the detection signal is detected. Can be performed based on the same signal. For this reason, the calculation cycles of the detection devices 50 ₁ , 50 ₂ , 50 ₃ can be made the same.

In the above embodiment, the vibration directions of the beam probes of the encoders 17 _Y1 and 17 _Y2 are the same Y-axis direction, and the detected displacement is the Y-axis direction displacement. The vibration centers of the beam probes of the encoders 17 _Y1 and 17 _Y2 are separated by L in the X-axis direction, and the X position of the midpoint is the same as the X position of the optical axis AX of the projection optical system PL. , without considering the Abbe error, the mean value of the measurement values of the encoder 17 _Y1, 17 _Y2 can be the Y position of reticle stage RST, and the measurement value of the encoder 17 _Y1, 17 _Y2, spacing of the measuring points Based on L, it is also possible to detect the amount of rotation of reticle stage RST about the Z axis.

Further, the drive signal D input to the encoders 17 _Y1 and 17 _Y2 is input to the encoder 17 _X, and the beam probe vibrates according to the drive signal D. That is, the frequency and phase of the beam probe oscillation of the encoder 17 _X are the same as the frequency and phase of the beams of the encoders 17 _Y1 and 17 _Y2 . Thus, the calculation cycle and the detection timing of the detection device 50 _3, detecting device 50 _1, and 50 ₂ of the same as those, the detection timing of the X displacement of the reticle stage RST, simultaneously with the detection timing of the Y displacement In addition, the circuit configurations of the detection devices 50 ₁ , 50 ₂ , and 50 ₃ can be made the same, and the design and manufacture of the device is facilitated.

Incidentally, the vibration of the three probes portion 19 _Y1, 19 _Y2, 19 _X beam probe, not completely necessary to synchronize, the probe unit 19 _Y1 vibration angle and frequency of beam probe, a beam probe of the probe portion 19 _Y1 As described above, the ratio between the vibration angular frequency and the vibration angular frequency of the beam probe of the probe unit 19 _X may be an integer ratio. The detection timing delay that occurs at that time can be absorbed by the stage control device 39.

  In this embodiment, the reticle stage RST and the encoder system 16 can be regarded as constituting one stage device.

Note that the surface shape of the grating 1 of the scales 18 ₁ and 18 ₂ may not be a sine wave shape but may be a rectangular wave shape. Further, the grating 1 may be one in which elements having different reflectances are alternately arranged. In short, it is only necessary that a specific pattern is arranged in the measurement direction.

  Various modifications can be made to the encoder system 16 of the above embodiment. For example, instead of oscillating the objective lens 7 and oscillating the beam probe as in the above embodiment, a mirror may be placed in the optical path of the laser beam and the mirror may be oscillated. Further, a diffraction grating may be placed in the optical path of the laser beam, and the diffraction grating may be vibrated.

  Further, for example, as shown in FIG. 8, on the optical path of the laser beam output from the laser diode 3, an acoustic optical device A / O that causes a change in diffraction angle or an electronic device that causes a change in refractive index. An optical device 5 such as E / O is inserted, and a sine wave control signal D is added to the optical device 5 so that the diffraction angle and the refractive index are changed in a sine wave shape to oscillate the beam probe on the grating 1. Good.

It is also possible to employ a probe portion 19 _Y1 ″ as shown in FIG. 9A. This probe has an acousto-optic effect in the optical path between the laser diode 3 and the beam splitter 6. A diffraction grating 5 ′ capable of arbitrarily setting the angle of the diffracted light is inserted.By the action of the diffraction grating 5 ′, the laser beam is divided into a zero-order diffracted light (main beam) and an outer first-order diffracted light (sub-beam). And reaches the grating 1. Each beam reflected by the grating 1 is reflected by the beam splitter 6 and received by the optical sensor 9. The grating 1 has a spatial frequency ω ′.

  The diffraction grating 5 ′ is a diffraction grating capable of adjusting the angle of diffracted light by, for example, an acousto-optic effect or an electro-optic effect. The driving device 11 inputs a sine wave signal to the diffraction grating 5 ′ in accordance with the input driving signal D. By this input, the angle of each first-order diffracted light on the grating 1 varies sinusoidally. Therefore, the sub beam detected by the optical sensor 9 is a signal modulated by the oscillation of the beam probe, and the vibration of the beam probe with respect to the peak of the grating 1 is obtained from this signal using the same principle as in the above embodiment. The distance from the center can be detected.

When such a probe is employed, as the optical sensor 9, as shown in FIG. 9B, a four-part optical sensor 9 ₃ for main beam detection and two sensors 9 ₁ for sub-beam detection, 9 ₂ are used.

The relative distance between the peak of the grating 1 and the vibration center of the beam probe is detected from one of the detection signals from the optical sensors 9 ₁ and 9 _{2 by} the same principle as in the above embodiment, as a result of receiving the two sub beams. Is possible. In the detection apparatus shown in FIG. 9B, the result of adding the detected amplitude / phase values detected from the signals from the optical sensors 9 ₁ and 9 ₂ is detected as the measured value of the encoder, and the result of subtraction is the laser. This is detected as the drift amount of the beam probe due to the position drift of the diode.

4 split photosensor _{9 1} of each of the sensors respectively and _{9 A, 9 B, 9 C} , 9 D, the output of _{9 A, 9 B, 9 C} , 9 D, to a, b, c, as d. Two signals (a + b + c + d and a + c−b−d) can be generated from the detection result of the main beam. Since these two signals have a phase difference of 90 degrees, these two signals are sent to a focus servo circuit (not shown) and used for focus control between the objective lens and the grating 1.

Various focused laser beams can be applied to the laser beam. For example, an electron beam, an ion beam, or another radiation beam can be applied. It is also possible to use a beam cross-sectional shape of the beam probe irradiated on the grating 1, an ellipse extending in the Y direction, or a linear shape. Further, for example, the detection accuracy can be improved by averaging the detection results by causing the beam probe of the probe 19 _X to vibrate in the Y-axis direction at a frequency higher than the oscillation frequency in the X direction.

  As an encoder, a magnetic medium can be applied as a scale, and a magnetic read head can be applied as a probe.

In the probe portions 19 _Y1 and 19 _{Y2 of} the above embodiment, a sensor for detecting the displacement of the objective lens 7 may be provided. In this case, the detection signal of the sensor can be the original frequency of the harmonics generated by the detection devices 50 ₁ , 50 ₂ , 50 ₃ . However, in this case, it is desirable to lock the phase of the output signal of the sensor using a phase signal emitted from the synchronization circuit 51 using a PLL circuit or the like.

In the above embodiment, the scale 18 ₂ is a two-dimensional diffraction grating, and the encoder 17 _Y2 and the encoder _X share a scale. However, the present invention is not limited to this, and the encoder 17 _Y2 and the encoder 17 _X Of course, they may be separated (that is, a scale in the Y-axis direction is provided and a scale in the X-axis direction is provided).

  Further, the scale may be a two-dimensional lattice, the number of beam probes may be one, and the vibration direction of the beam probe may be moved in an arc shape in the XY plane instead of one-dimensional. Also in this case, it is possible to measure the relative distance between the peak of the scale in the X-axis direction and the Y-axis direction and the vibration center of the beam probe. In addition, after one beam probe is vibrated in the X-axis direction, it may be vibrated in the Y-axis direction, and position information regarding the X-axis direction and position information regarding the Y-axis direction may be detected alternately.

  A plurality of beam probes may be prepared for one encoder. For example, a beam probe in which two beam probes having the same vibration frequency and different vibration phases are arranged side by side in the periodic direction of the scale can be used. The distance between the two beam probes is defined as a distance based on the phase difference of the probe oscillation and the spatial angular frequency of the scale. In this way, it is only necessary to detect the fundamental frequency component at the time of position measurement, and the bandwidth required for the detection apparatus can be reduced. In the case of a single probe, a bandwidth that is at least twice the fundamental frequency is required.

  It is also possible to extend the cross-sectional shape of these beams in an elliptical shape or a linear shape.

  The probe need not be a beam probe as in the above embodiment. For example, an encoder using a physical probe composed of tungsten, a Pt-Ir wire, or the like having a sharp tip may be used. In this case, it is necessary to make the scale conductive, generate a tunnel current between the probe and the scale, and measure the output voltage with an IV converter. This output voltage includes the vibration frequency component of the probe and the vibration frequency component of the scale. Similar to the above embodiment, the peak of the scale and the probe are detected by detecting the phase or the like by the vibration frequency component of the probe. The relative distance from the vibration center can be acquired.

  When a physical probe is applied, the detection method is not limited to the method for generating the tunnel current described above. For example, a capacitance type that detects the capacitance between the probe and the scale may be used, or a magnetic field or an electric field that is periodically provided on the scale may be detected.

  In the above embodiment, the drive signal of the beam probe drive device input to the probe unit of each encoder is used as it is as the original frequency of the modulation signal in the detection device, but this is not restrictive. For example, when a physical probe is used, the actual vibration of each probe may be detected, and the phase of the drive signal of the drive device used as the original frequency may be matched with the actual vibration phase. In this way, since the phase shift of the probe vibration is corrected, it is possible to realize stable position measurement in the encoder even if the vibration frequency is close to the resonance frequency of the probe.

  In addition, the configuration of the detection apparatus that detects the position information from the detection signal of the probe is not limited to that of the above-described embodiment, and various modifications can be considered. Such a modified example of the detection device is disclosed in US Pat. No. 6,693,686, and will not be described in detail.

  In the above-described embodiment, the case where the position information of the reticle stage RST is measured using the encoder described above has been described. However, in order to realize high-accuracy exposure in actual scanning exposure, the projection optical system PL is not affected. It is necessary to detect relative position information of reticle stage RST. In this case, the position information of the projection optical system PL is also detected by the above-described encoder, and the relative position of the reticle stage RST with respect to the projection optical system PL is calculated based on the position information and the position information of the reticle stage RST. The calculation result may be used for position control of reticle stage RST.

  In the above embodiment, the case where the present invention is applied to the measurement of the position of reticle stage RST has been described. However, the present invention is not limited to this, and the present invention may be applied to the measurement of the position of wafer stage WST. Of course it is good. Also in this case, it is desirable to finally calculate the relative position of wafer stage WST with respect to projection national studies system PL.

  As described above, relative position information between reticle stage RST and projection optical system PL and relative position information between wafer stage WST and projection optical system PL are detected by the encoder system of the present invention, and based on the position information. If the stage WST and RST are relatively scanned and scanning exposure is performed, the circuit pattern on the reticle and the like can be transferred onto the wafer W with high accuracy.

  Further, the present invention is not limited to the step-and-scan type exposure apparatus as in the above-described embodiment, but includes a step-and-repeat type or proximity type exposure apparatus (such as an X-ray exposure apparatus). The present invention can also be applied to the same type of exposure apparatus.

In the above embodiment, as a light source, a far-ultraviolet light source such as a KrF excimer laser or an ArF excimer laser, a vacuum ultraviolet light source such as an F ₂ laser, an ultrahigh pressure mercury lamp that emits a bright line (g-line, i-line, etc.) in the ultraviolet region, etc. Can be used. In addition, when light in the vacuum ultraviolet region is used as the illumination light for exposure, it is not limited to the laser beam output from each of the light sources described above, but a single infrared or visible region oscillated from a DFB semiconductor laser or fiber laser. For example, harmonics obtained by amplifying a wavelength laser beam with a fiber amplifier doped with erbium (Er) (or both erbium and ytterbium (Yb)) and converting the wavelength into ultraviolet light using a nonlinear optical crystal may be used. .

  Furthermore, the present invention may be applied to an exposure apparatus that uses EUV light, X-rays, or charged particle beams such as electron beams and ion beams as exposure illumination light. In addition, the present invention may also be applied to an immersion type exposure apparatus that is disclosed in, for example, International Publication WO99 / 49504 and the like and in which a liquid is filled between the projection optical system PL and the wafer W. Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 10-214783 and International Publication WO98 / 40791, an exposure apparatus includes an exposure position where a reticle pattern is transferred via a projection optical system, and wafer alignment. A twin wafer stage type in which a wafer stage is arranged at each measurement position (alignment position) where mark detection by the system is performed, and the exposure operation and the measurement operation can be performed substantially in parallel may be used. Further, the projection optical system PL may be any of a refraction system, a catadioptric system, and a reflection system, and may be any one of a reduction system, an equal magnification system, and an enlargement system.

  In the above-described embodiment, a light-transmitting mask in which a predetermined light-shielding pattern (or phase pattern / dimming pattern) is formed on a light-transmitting substrate, or a predetermined reflecting pattern is formed on a light-reflecting substrate. Although the formed light reflection type mask is used, an electronic mask that forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed may be used instead of these masks. Such an electronic mask is disclosed in, for example, US Pat. No. 6,778,257.

  Note that the above-described electronic mask is a concept including both a non-light-emitting image display element and a self-light-emitting image display element. Here, the non-light-emitting image display element is also called a spatial light modulator, and is an element that spatially modulates the amplitude, phase, or polarization state of light. It can be divided into a reflective spatial light modulator. The transmissive spatial light modulator includes a transmissive liquid crystal display (LCD), an electrochromic display (ECD), and the like. The reflective spatial light modulator includes a DMD (Digital Mirror Device or Digital Micro-mirror Device), a reflective mirror array, a reflective liquid crystal display element, an electrophoretic display (EPD), an electronic paper (or electronic paper). Ink), and a light diffraction light valve (Grating Light Value).

  Self-luminous image display elements include CRT (Cathod Ray Tube), inorganic EL (Electro Luminescence) display, field emission display (FED), plasma display (PDP), A solid light source chip having a light emitting point, a solid light source chip array in which a plurality of chips are arranged in an array, or a solid light source array in which a plurality of light emitting points are formed on a single substrate (for example, an LED (Light Emitting Diode) display, OLED) (Organic Light Emitting Diode) display, LD (Laser Diode) display, etc.). Note that when a fluorescent material provided in each pixel of a known plasma display (PDP) is removed, a self-luminous image display element that emits light in the ultraviolet region is obtained.

  The present invention is not limited to an exposure apparatus for manufacturing a semiconductor, but is used for manufacturing a display including a liquid crystal display element. An exposure apparatus for transferring a device pattern onto a glass plate and a device used for manufacturing a thin film magnetic head. The present invention can also be applied to an exposure apparatus that transfers a pattern onto a ceramic wafer, and an exposure apparatus that is used for manufacturing an imaging device (CCD or the like), micromachine, organic EL, DNA chip, and the like. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates or silicon wafers, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern. Here, in an exposure apparatus using DUV (far ultraviolet) light, VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used. As a reticle substrate, quartz glass, fluorine-doped quartz glass, meteorite, Magnesium fluoride or quartz is used. Further, in a proximity type X-ray exposure apparatus or an electron beam exposure apparatus, a transmission mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate.

  The semiconductor device includes a step of designing a function and 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 a reticle pattern on the wafer by the exposure apparatus 100 of the above-described embodiment. It is manufactured through a transfer step, a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like.

  In addition, the present invention can be applied to manufacture of a master disk such as an optical disk, and diamond processing and finishing of a special mirror mounted on an artificial satellite.

  As described above, the encoder system of the present invention is suitable for detecting position information of an object, and the stage device is suitable for use in a necessary manufacturing process that requires highly accurate positioning. This exposure apparatus is suitable for lithography processes such as semiconductor devices.

It is a figure which shows schematic structure of the exposure apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows an example of a structure of a probe part. It is a figure which shows the structure of an encoder. It is a block diagram which shows the general structure of a detection apparatus. It is a block diagram which shows the other detailed structure of a detection apparatus. FIG. 6A is a timing chart showing the relationship between the calculation cycle of the detection apparatus and the oscillation cycle of the probe, and FIG. 6B shows the relationship between the oscillation cycles of the probes of the two encoders being an integral multiple. FIG. 6C is a timing chart showing the relationship between the calculation cycle of the detection device and the oscillation cycle of the probe, and FIG. 6C shows the calculation cycle of the detection device when there is a phase difference between the vibrations of the probes of the two encoders. It is a timing chart which shows the relationship with the oscillation period of a probe. It is a figure which shows the other structural example of an encoder system. It is a figure which shows the other structural example (the 1) of a probe part. FIG. 9A is a diagram illustrating another configuration example (No. 1) of the probe unit, and FIG. 9B is a diagram illustrating another configuration example of the detection device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Grating, 3 ... Laser diode, 4 ... Collimator lens, 5 ... Optical device, 6 ... Beam splitter, 7 ... Objective lens, 8 ... Focus lens, 9 ... Optical sensor, 10 ... Illumination system, 11 ... Drive apparatus, 16 , 16 '... encoder _{system, 17 X, 17 Y1, 17} Y2 ... encoder, 18 _1, 18 ₂ ... _{scale, 19 Y1, 19 Y2, 19} X, 19 Y1', 19 Y2 ', 19 X' ... probe portion, 21 ... reticle stage drive section, 24 ... wafer stage drive section, 32 ... opening, 38 ... laser interferometer, 39 ... stage controller, 50 _1, 50 _2, 50 ₃ ... detection device, 61 ... filter, 62 ... frequency Synthesizer, 63 ₁ , 63 ₂ ... multiplier, 64 ... adder, 65 ... loop filter, 66 ... integrator, 67 ₁ , 67 ₂ ... adder, 68 ₁ , 68 ₂ ... sine wave function generator, 7 0 ... transducer, 71 ... branch device 74, 75 ... half mirror, 77 ... mirror, 91 ... Filter, 92 ... frequency synthesizer, 93 _1, 93 ₂ ... multiplier, 94 ... phase detector, 96 ... amplitude Detection unit, 97: distance identification unit, 100: exposure apparatus, AX: optical axis, IL: illumination light, PL: projection optical system, RST: reticle stage, W: wafer, WST: wafer stage.

Claims (12)

A first scale having a pattern arranged in a first direction; a first probe for detecting a pattern of the first scale and outputting an output signal modulated with a first periodic signal in the first direction; A first encoder comprising: a detection device that detects relative position information between the first scale and the first probe based on an output signal output from the first probe;
A second scale having a pattern arranged in a second direction; a second probe for detecting a pattern of the second scale and outputting an output signal modulated with a second periodic signal in the second direction; A second encoder comprising: a detection device that detects relative position information between the second scale and the second probe based on an output signal output from the second probe;
An encoder system comprising: a synchronization device that synchronizes the first periodic signal and the second periodic signal. The synchronization device includes:
2. The encoder system according to claim 1, wherein a ratio between the frequency of the first periodic signal and the frequency of the second periodic signal is an integer ratio. The synchronization device includes:
The encoder system according to claim 2, wherein the frequency of the first periodic signal and the frequency of the second periodic signal are the same, and the phase difference is maintained at zero. The first probe has a first vibration element that vibrates light applied to the first scale in the first direction,
The second probe has a second vibration element that vibrates light irradiating the second scale in the second direction,
The synchronization device synchronizes a drive signal for vibrating the first vibration element with a drive signal for vibrating the second vibration element. The encoder system according to one item. A vibrating element that vibrates light emitted from the light source;
A supply system for supplying light via the vibration element to the first probe and the second probe;
The first probe irradiates the first scale with light supplied from the supply system oscillated in the first direction;
The said 2nd probe irradiates the said 2nd scale in the state oscillated in the said 2nd direction with the light supplied from the said supply system, The Claim 1 characterized by the above-mentioned. Encoder system.   The encoder system according to claim 1, wherein the first direction and the second direction are the same direction.   A third scale having a pattern arranged in a third direction different from the first direction and the second direction, and a pattern of the third scale are detected and modulated with a third periodic signal in the third direction. A third encoder comprising: a third probe that outputs the output signal; and a detection device that detects relative position information between the third scale and the third probe based on the output signal output from the third probe. The encoder system according to any one of claims 1 to 6, further comprising: The synchronization device includes:
The encoder system according to claim 7, wherein a ratio of the frequency of the first periodic signal, the frequency of the second periodic signal, and the frequency of the third periodic signal is an integer ratio. The synchronization device includes:
8. The encoder system according to claim 7, wherein the frequency of the first periodic signal, the frequency of the second periodic signal, and the frequency of the third periodic signal are the same, and the phase difference is maintained at zero. . In a stage apparatus comprising a stage that moves in a predetermined direction and a measuring device that measures the position of the stage in the predetermined direction,
As the measuring device, it has the encoder system according to any one of claims 1 to 6,
The stage device, wherein the first encoder and the second encoder constituting the encoder system are arranged with a predetermined interval with respect to a direction orthogonal to the predetermined direction. In a stage device comprising a stage and a measuring device for measuring the position of the stage,
As the measurement device, the encoder system according to any one of claims 7 to 9,
The stage device, wherein the first encoder and the second encoder measure a position in a predetermined direction of the stage, and the third encoder measures a position in a direction orthogonal to the predetermined direction. An exposure apparatus for transferring a predetermined pattern onto a photosensitive object,
The stage apparatus according to claim 10 or 11, wherein one of the photosensitive object and the member on which the predetermined pattern is formed is placed on a stage.
A beam source for irradiating the photosensitive object with an energy beam.

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