JP2008171961A - Laser device, method and device for exposure, and manufacturing method of device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser device capable of outputting two laser beams having substantially the same characteristics such as central wavelength or the like. <P>SOLUTION: The laser device is provided with first and second laser light sources 1A, 1B which have band narrowing modules LNM and emit laser light LC1, LC2 by pulse emission, a monitor unit 66B for measuring the wavelength information of the laser light, movable mirrors 65B, 67 for guiding selectively either of the laser lights LC1, LC2 to the monitor unit 66B and a control unit 35A for controlling wavelengths of the laser light LC1, LC2 through the band narrowing modules LNM in the laser light sources 1A, 1B based on the measuring result of the monitor unit 66B. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser technique for combining and outputting a plurality of laser beams in parallel or coaxially, and to an exposure technique and a device manufacturing technique using this laser technique.

  In a photolithography process for manufacturing a device such as a semiconductor element (microdevice, electronic device, etc.), a wafer on which a circuit pattern formed on a reticle (or a photomask, etc.) is coated with a photoresist via a projection optical system In order to perform projection exposure on a glass plate (or glass plate, etc.), an exposure apparatus such as a stationary exposure type (collective exposure type) projection exposure apparatus such as a stepper and a scanning exposure type projection exposure apparatus such as a scanning stepper is used. ing. In such an exposure apparatus, a KrF excimer laser (wavelength 248 nm) is used as an exposure light source in order to shorten the wavelength of exposure light and improve resolution in response to further miniaturization and higher integration of semiconductor integrated circuits and the like. Further, a laser light source that generates pulsed laser light from the far ultraviolet region to the vacuum ultraviolet region, such as an ArF excimer laser (wavelength 193 nm), is used.

  In addition to shortening the exposure light wavelength, one of the exposure methods for improving the imaging performance is a double exposure method. This is because, for example, when a pattern in which a periodic pattern and an isolated pattern are mixed is exposed on the same layer on the wafer, the reticle pattern is a first pattern including a periodic pattern and a second pattern including an isolated pattern. High imaging performance is obtained by dividing the pattern into two patterns and performing double exposure by sequentially optimizing the exposure conditions of these two patterns.

  Conventionally, when exposure is performed by such a double exposure method, the first exposure is performed using a first reticle in which one or more first patterns are formed, and then the reticle is applied to the second pattern. The second exposure was performed by exchanging with one or a plurality of second reticles. However, high throughput cannot be obtained by performing exposure by exchanging the reticle in this way.

Therefore, the first and second patterns are formed on a single reticle, the reticle pattern is transferred to adjacent first and second shot areas on the wafer by scanning exposure, and then the wafer is scanned. The first and second patterns are duplicated in the second shot area by stepping in the direction by one shot area and transferring the reticle pattern to the second and third shot areas on the wafer. An exposure method for exposure has been proposed (see, for example, Patent Document 1). In this exposure method, the illumination conditions for the two patterns can be individually optimized by switching the illumination conditions when the exposure light illuminates the first and second patterns during the scanning exposure.
JP-A-11-111601

  When performing exposure by the double exposure method combined with the scanning exposure as described above, the first and second patterns are each illuminated under optimal illumination conditions, and switching from exposure of the first pattern to exposure of the second pattern is performed. To perform smoothly (at high speed), the exposure apparatus is provided with two illumination systems (for example, the last stage condenser lens system may be shared), and the exposure light from the two illumination systems is switched. However, it is conceivable to illuminate the first and second patterns. In this case, assuming that a laser light source is used as the exposure light source, the laser light from one laser light source is divided into two by a half mirror or the like and supplied to the two illumination systems. Since (energy per unit time) decreases, there is a problem that it is difficult to increase the throughput of the exposure process.

It is also conceivable to use two laser light sources in parallel as the exposure light source, but in this case, if the characteristics such as the center wavelength of the laser light output from the two laser light sources are different, the projection optical system is connected. Due to the difference in image characteristics (such as chromatic aberration), the image forming performance of the pattern after double exposure may be deteriorated.
Furthermore, even in laser processing machines other than the exposure apparatus, in order to increase the throughput of the processing process without increasing the cost burden of the laser light source, the cost is lower than the cost of a plurality of laser light sources and Development of a laser device capable of generating the laser beam is desired.

  When the laser light source is a pulse light source such as an excimer laser light source, the pulse energy and the oscillation frequency may be increased in order to increase the output. However, in the case of an ArF excimer laser light source, for example, the upper limit of the oscillation frequency is currently about 4 kHz, and it is difficult to further increase the oscillation frequency while maintaining the laser characteristics stably. On the other hand, if the peak level is increased in order to increase the pulse energy, the optical members constituting the illumination optical system and projection optical system of the exposure apparatus may be damaged. Therefore, in order to increase the pulse energy, it is desirable to increase the pulse width without increasing the peak level.

In view of such circumstances, the present invention is a laser capable of combining two laser beams having substantially the same characteristics such as the center wavelength in parallel or coaxially and outputting them so that they can be used, for example, when performing exposure by a double exposure method. It is a first object to provide an apparatus.
A second object of the present invention is to provide an inexpensive laser device that can output two laser beams by combining them in parallel or coaxially.

A third object of the present invention is to provide a laser apparatus including two laser light sources that can easily widen the pulse width.
A fourth object of the present invention is to provide an exposure technique and a device manufacturing technique capable of performing exposure by a double exposure method using a laser apparatus that outputs two laser beams.

  A first laser device according to the present invention is a laser device that outputs two laser beams, includes a first wavelength selection optical system (LNM) that controls the wavelength of the laser beams, and outputs the first laser beams. A second laser light source (1B) that has a first laser light source (1A) that emits pulses and a second wavelength selection optical system (LNM) that controls the wavelength of the laser light, and emits pulses of the second laser light. ), A wavelength monitor (66B) for measuring the wavelength information of the laser beam, and an optical path switching optical system (65B, 67) for selectively guiding one of the first and second laser beams to the wavelength monitor. Based on the wavelength information of the first and second laser beams measured by the wavelength monitor, the wavelengths of the first and second laser beams are determined via the first and second wavelength selection optical systems. And a control system (45A) for controlling .

According to the present invention, based on the measurement result of the wavelength monitor, the center wavelength of the first and second laser beams and the like are matched via the first and second wavelength selection optical systems. Two laser beams having substantially the same characteristics can be output in parallel.
The second laser device according to the present invention is a laser device that outputs two laser beams, each of which includes first and second laser light sources (62A, 62B) that emit laser light pulses, and the first laser device. A first branching / combining optical system (63A) for branching the first laser beam (LC1B) from the laser beam (LC1) output from the laser light source and combining and outputting the second laser beam; A second branching and combining optical system (63B) for branching the third laser beam (LC2B) from the laser beam (LC2) output from the second laser light source and for combining and outputting the fourth laser beam; The first laser beam is guided to the first branching optical system as the second laser beam, and the third laser beam is guided to the second branching optical system as the fourth laser beam. Optical optics (64A ~ 4D) and provided with, and outputs two laser beams outputted from the first and second branch combining optical system in parallel.

According to the present invention, the peak level of the pulse laser beam output from the first and second branching / combining optical systems is approximately ½, and the pulse width is approximately doubled. Moreover, the pulse widths (characteristics) of the pulsed laser beams output in parallel from the two branching / combining optical systems are substantially the same.
A third laser device according to the present invention is a laser device that outputs two laser beams, and a laser light source (50) that emits a pulse of laser light and a laser beam output from the laser light source for each pulse. Branch optical systems (52, 53) that alternately output first and second laser beams having different optical paths, and first and second amplifiers that amplify and output the first and second laser beams in parallel, respectively. Laser amplifiers (55A, 55B).

According to the present invention, by using one laser light source for wavelength control whose output may be small and two laser amplifiers that do not necessarily require a laser resonator, two central wavelengths can be obtained with an inexpensive configuration. Laser beams having the same characteristics can be output in parallel.
A fourth laser device according to the present invention is a laser device that emits a pulsed laser beam, and each of the first and second laser light sources (62A, 62B) that emits a pulsed laser beam; The synthesizing optical system (63A, 63C) for synthesizing the laser beams from the second laser light source substantially coaxially and the first and second laser light sources at the same pulse frequency and substantially equivalent to the emission time of each pulse light And a control system (45B) that emits light with a time difference.

According to the present invention, the pulse width can be easily widened with a simple configuration without changing the peak level of the pulse laser beam.
Next, in the exposure method according to the present invention, the substrate (W) is exposed with the exposure beam through the pattern and the projection optical system (PL), and the substrate is synchronized with the movement of the pattern in the first direction. In the corresponding second direction, the two laser beams output in parallel from the laser apparatus (1A, 1B, 45A) of the present invention are used as the first and second illumination beams, The first and second pattern regions (52A, 52B) are formed adjacent to the first direction, and the pattern is moved in the first direction, and the first pattern region is within the field of view of the projection optical system. When passing, the substrate is exposed by illuminating the first pattern region with the first illumination light using the first illumination region (10AP) whose width in the first direction is variable, and the second Pattern area passes through its field of view When and, width of the first direction in which illuminating the second pattern area at the second illumination light to expose the substrate using a variable of the second illumination area (10BP).

According to the present invention, exposure can be performed by the double exposure method by exposing the image of the first pattern area and the image of the second pattern area on the substrate in an overlapping manner.
In addition, the first exposure apparatus according to the present invention is synchronized with the movement of the pattern in the first direction in a state where the substrate (W) is exposed with the illumination light through the pattern and the projection optical system (PL). In an exposure apparatus that moves the substrate in the corresponding second direction, the laser apparatus (1A, 1B, 45A) for outputting two laser beams in parallel according to the present invention, and the first direction in the field of view of the projection optical system The first illumination region (10AP) having a variable width is illuminated with a first illumination light composed of one of the laser beams output from the laser device, and a width in the first direction within the field of view is variable. An illumination optical system (IU) that illuminates the illumination area (10BP) with the second illumination light composed of the other laser light output from the laser device, and the first and second positions according to the position of the pattern in the first direction Its second in the second illumination area Lighting control device for controlling the direction of the width is obtained with (42R, 10A, 10B, 11A, 11B) and a.

  According to the present invention, the first and second pattern regions are formed in a predetermined direction on the pattern, and the first is scanned when the substrate is scanned in synchronization with the scanning of the pattern in the predetermined direction. And the 1st and 2nd pattern area | region is illuminated in a 2nd illumination area | region, and the board | substrate is exposed. Then, by exposing the image of the first pattern area and the image of the second pattern area on the substrate in an overlapping manner, exposure can be performed by a double exposure method.

A second exposure apparatus according to the present invention is an exposure apparatus that exposes a substrate (W) with illumination light through an optical member (PL), and includes the laser apparatus (71, 45A) of the present invention. Is used as the illumination light.
A device manufacturing method according to the present invention uses the exposure method or exposure apparatus of the present invention. According to the present invention, for example, by applying the double exposure method, a plurality of circuit patterns having different illumination conditions optimal for one layer on the substrate can be formed with high accuracy.

  In addition, although the reference numerals in parentheses attached to the predetermined elements of the present invention correspond to members in the drawings showing an embodiment of the present invention, each reference numeral of the present invention is provided for easy understanding of the present invention. The elements are merely illustrative, and the present invention is not limited to the configuration of the embodiment.

[First Embodiment]
A first embodiment of the laser apparatus of the present invention will be described below with reference to FIGS. In the present embodiment, the present invention is applied to a laser light source device that outputs two pulsed laser beams having substantially the same wavelength as an ArF excimer laser beam (wavelength 193 nm). In the present invention, _two laser beams having substantially the same wavelength as the KrF excimer laser (wavelength 248 nm), Ar ₂ excimer laser (wavelength 126 m), F ₂ laser (wavelength 157 nm), etc. The present invention can be similarly applied to a laser light source device that emits two laser beams in pulses.

  FIG. 1 shows a laser light source device of this example. In FIG. 1, this laser light source device includes an oscillation laser light source 50 that emits a pulse of a laser light (seed light) LB having a controlled output and a small output. The optical path for splitting the optical path of the laser beam LB alternately for each pulse to generate two laser beams LB1 and LB2, and the same wavelength characteristics by amplifying the laser beams LB1 and LB2 and the same Laser amplification chambers 55A and 55B having the same configuration that emit laser pulses LC1 and LC2 of light emission timing are provided, and a control unit 35 including a computer that controls these operations. The laser beams LC1 and LC2 output in parallel are used as exposure light in an exposure apparatus main body that exposes a reticle pattern (not shown) on a substrate such as a wafer. The control unit 35 controls the exposure apparatus main body. On the other hand, a light emission trigger pulse TP indicating the pulse emission timing of the laser beams LC1 and LC2, and control information indicating set target values of laser characteristics such as the center wavelength, spectrum width, and pulse energy of the laser beams LC1 and LC2, and Is supplied.

Specifically, the laser light source 50 for oscillation includes a laser gas mixed with argon (Ar) and fluorine (F ₂ ) and a gas for diluting the laser gas (for example, a mixture of neon (Ne) and helium (He). Gas) and a discharge chamber 51 in which a pair of electrodes for discharge are installed, and a narrow-band module (Line Narrow Module) (hereinafter referred to as a sandwiching chamber 51 in the longitudinal direction) , LNM) and an output mirror OC, and a discharge circuit section (not shown) including a power source for discharging between electrodes in the chamber 51. The discharge circuit unit discharges between the electrodes in synchronization with the trigger signal TS1 from the control unit 35. Both ends of the chamber 51 through which the laser beam LB passes are used to reduce the reflection loss of the P-polarized light component (polarized light component parallel to the incident surface) of the laser light and to prevent the position shift, so that the Brewsters in opposite directions to each other. It is sealed with a window that is inclined at the corner. Therefore, the laser beam LB emitted from the laser light source 50 is linearly polarized light polarized in a direction parallel to the paper surface of FIG.

  The band narrowing module LNM includes, for example, three or four magnifying prisms and an optical element such as a diffraction grating which is a wavelength selection element. Note that the narrowband module LNM may be configured by an etalon that is a wavelength selection element and an optical element such as a total reflection mirror. Further, in practice, a beam splitter (not shown) having a low reflectivity is installed after the output mirror OC, and a part of the laser beam LB reflected by the beam splitter is a center wavelength, a spectrum width, and a pulse of the laser beam. This is supplied to a monitor unit (not shown) that measures laser characteristic information such as energy, and the measurement result of this monitor unit is supplied to the control unit 35. The control unit 35 drives the optical member of the narrowband module LNM based on the measurement result of the monitor unit, thereby setting the center wavelength and the spectral width of the laser beam LB output from the laser light source 50 as described above. Set to the set target value included in.

  The branching optical system includes a laser beam LB1 in a first state (P-polarized light) whose polarization direction is not rotated, and a laser beam LB2 in a second state (S-polarized light) whose polarization direction is rotated 90 °. Of the laser light outputted from the polarization modulation element 52, the laser light LB1 is passed through the laser amplification chamber 55A as it is, and the laser beam LB2 is a polarization beam splitter that bends the optical path by 90 degrees ( (Hereinafter referred to as PBS) 53, and a mirror 54 for sending the laser beam LB2 to the laser amplification chamber 55B in parallel with the laser beam LB1. As an example, the polarization modulation element 52 outputs the laser beam LB1 when the control signal TE1 from the control unit 35 is at a low level, and outputs the laser beam LB2 when the control signal TE1 is at a high level.

  As the polarization modulation element 52, a Pockels cell or a car cell that electrically changes the birefringence of the crystal (or liquid) and changes the polarization direction of the light passing through the inside (however, a polarizer and an analyzer are not required). 2) can be used. In addition, as the polarization modulation element 52, a magneto-optic modulation element such as a Faraday cell that uses a magneto-optical effect such as polarization plane rotation by a magnetic field, a modulation element that changes the polarization direction using a photoelastic effect, or the like can be used. .

  Similarly to chamber 51, laser amplification chambers 55A and 55B include a discharge chamber in which a laser gas or the like is enclosed and a pair of electrodes, and a power source for discharging between the electrodes. A discharge circuit unit (not shown). The discharge circuit unit discharges between the electrodes in synchronization with the trigger signals TS2 and TS3 from the control unit 35. In this example, the laser amplification chambers 55A and 55B are not provided with a laser resonator, and have a function of amplifying the laser beams LB1 and LB2 output from the laser light source 50. That is, in the laser light source device of this example, the laser light source 50 is a master oscillator (Master Oscillator (MO)), and the laser light source including the laser amplification chambers 55A and 55B is an optical output amplifier (Power Amplifier (PA)). It is a laser system. Therefore, the trigger signals TS1 and TS2 are supplied so that the laser beams LB1 and LB2 become high level at the timing when the laser beams LB1 and LB2 enter the laser amplification chambers 55A and 55B. Further, since the laser beams LB1 and LB2 are respectively P-polarized light and S-polarized light, the window portions 55Aa and 55Ab and the window portions 55Ba and 55Bb of the laser amplification chambers 55A and 55B are in-plane and perpendicular to the paper surface of FIG. The rotation angle is set so as to be the Brewster angle in a smooth plane. The laser beams LC1 and LC2 output in parallel are linearly polarized light whose polarization directions are orthogonal to each other, but in order to make the polarization directions of the laser beams LC1 and LC2 parallel, for example, a ½ wavelength plate immediately after the laser amplification chamber 55B. May be installed.

  An example of the light emission operation of the laser light source device of FIG. 1 will be described with reference to FIG. 2A to 2H, the horizontal axis represents time t, the vertical axes in FIGS. 2A to 2E represent signal intensity, and the vertical axes in FIGS. 2F to 2H represent light intensity. First, as shown in FIG. 2A, a light emission trigger pulse TP that is a high-level pulse at a predetermined frequency is supplied from the exposure apparatus main body (not shown) to the control unit 35 in FIG. 1, and the control is performed accordingly. In the unit 35, a trigger signal TS1 (FIG. 2B) having the same frequency synchronized with the light emission trigger pulse TP and a control signal TE1 (FIG. 2 (2) whose level is inverted every time the light emission trigger pulse TP becomes a high level pulse. C)) is supplied to the laser light source 50 and the polarization modulator 52. Further, the control unit 35 generates trigger signals TS2 (FIG. 2D) and TS3 (FIG. 2E) that become high level at the same timing as the odd-numbered and even-numbered high-level pulses of the trigger signal TS1, respectively. Supply to laser amplification chambers 55A and 55B. As a result, as shown in FIG. 2F, the laser light source 50 outputs a laser beam LB having a small output at the same oscillation frequency as the light emission trigger pulse TP in synchronization with the trigger signal TS1. Further, the laser beam LC1 (FIG. 2G) obtained by amplifying odd-numbered pulses of the laser beam LB is output from one laser amplification chamber 55A, and the even number of the laser beam LB is output from the other laser amplification chamber 55B. Laser light LC2 (FIG. 2 (H)) obtained by amplifying the second pulse is output. The frequencies of the output laser beams LC1 and LC2 are ½ of the frequency of the laser beam LB (seed beam) (the frequency of the light emission trigger pulse TP), and the laser beams LC1 and LC2 have a center wavelength and a spectral width. It is the same as the laser beam LB.

  As described above, according to the laser light source device of this example, the oscillation laser light source 50 is shared by the two laser amplification chambers 55A and 55B for amplification, and therefore includes the oscillation chamber and the amplification chamber 2 respectively. Compared with the case of using a single laser light source device, two laser beams LC1 and LC2 having the same laser characteristics such as the center wavelength can be pulsed in parallel at a low cost. Further, since the discharge voltage (amplification factor) in the laser amplification chambers 55A and 55B can be controlled independently, the pulse energies of the emitted laser beams LC1 and LC2 can be controlled independently of each other.

  Further, when generating ArF excimer laser light, the maximum oscillation frequency capable of stably maintaining the laser characteristics of the laser amplification chambers 55A and 55B is about 4 kHz to 6 kHz, but the output of the laser light source 50 for oscillation is quite small. In the laser light source 50, the laser beam LB can be generated at an oscillation frequency that is about twice the maximum oscillation frequency of the laser amplification chambers 55A and 55B while maintaining the laser characteristics stably. Therefore, the oscillation frequencies of the laser beams LC1 and LC2 can be increased to the maximum oscillation frequency of the current ArF excimer laser, respectively.

In addition, instead of the oscillation laser light source 50 (gas laser light source) of the laser light source device of FIG. 1, as shown in FIG. 3A, the basic is pulse laser light having a predetermined frequency (the angular frequency is ω). A fundamental wave generator 56 of a solid-state laser light source system that generates a wave LA, an optical fiber 57 that transmits the fundamental wave LA, and an eighth harmonic of the fundamental wave LA that is output from the optical fiber 57 (angular frequency is 8Ω). You may use the laser light source device provided with the wavelength conversion part 58 which produces | generates and outputs the 8th harmonic as laser beam LB. In this example, since the wavelength of the laser beam LB is the same as that of the ArF excimer laser (wavelength 193 nm), the fundamental wave LA is near-infrared light having a wavelength of 1544 nm (eight times 193 nm). Assuming that this is generalized and the wavelength converter 58 generates a k-fold harmonic of the fundamental wave LA (k is an integer of 2 or more), and the wavelength of the laser beam LB after conversion is λB, the fundamental wave The wavelength λA of LA may be k · λB. When it is desired to set the wavelength of the laser beam LB to 157 nm, which is the same as that of the F ₂ laser, as an example, the fundamental wave generation unit 56 generates a fundamental wave LA having a wavelength of 1570 nm, and the wavelength conversion unit 58 generates a tenth harmonic (k = 10 ).

  As an example, the fundamental wave generation unit 56 includes a semiconductor laser that generates laser light having an oscillation wavelength of 1544 nm, which is a single-mode continuous wave, and an optical modulation element that converts the laser light that is the continuous wave into pulsed light ( And an optical fiber amplifier that amplifies the pulsed light. As the semiconductor laser, for example, a distributed feedback (DFB) semiconductor laser having an indium / gallium / arsenic / phosphorus (InGaAsP) structure can be used. As the optical fiber amplifier, an erbium-doped optical fiber amplifier or the like can be used.

  Next, FIG. 3B shows a configuration example of the wavelength converter 58 in FIG. 3A. In FIG. 3B, the fundamental wave LA emitted from the optical fiber 57 is a condensing lens. The light enters the nonlinear optical crystal 60A via 59A and is converted into a second harmonic of an angular frequency of 2ω. Then, the second harmonic emitted from the nonlinear optical crystal 60A enters the nonlinear optical crystal 60B via the condenser lens 59B, and is converted into a fourth harmonic having an angular frequency of 4ω. The emitted 4th harmonic enters the nonlinear optical crystal 60C through the condenser lens 59C and is converted into an 8th harmonic having an angular frequency of 8ω. Then, the 8th harmonic emitted from the nonlinear optical crystal 60C is emitted as a laser beam LB composed of a parallel light flux through a collimator lens 59D. As described above, the wavelength conversion unit 58 includes the condenser lenses 59A to 59C, the nonlinear optical crystals 60A to 60C, and the collimator lens 59D.

In FIG. 3B, the nonlinear optical crystals 60A and 60B can be formed from, for example, LiB ₃ O ₅ (LBO) crystals, and the nonlinear optical crystal 60C can be formed from, for example, Sr ₂ Be ₂ B ₂ O ₇ (SBBO) crystals. . In addition to the combination of crystals that generate double harmonics, the wavelength converter 58 includes crystals that generate harmonics of the sum frequency and / or difference frequency, and crystals that generate double or higher harmonics. It is also possible to comprise from the combination with. The detailed configuration of the fundamental wave generation unit 56 and the wavelength conversion unit 58 in FIG. 3A and various modifications thereof are disclosed in, for example, the pamphlet of International Publication No. 01/20651 by the present applicant.

  The other structure of the laser light source device of FIG. 3A is the same as that of the laser light source device of FIG. 1, and the laser light LB emitted from the wavelength conversion unit 58 is branched into laser light LB1 and LB2, and then laser Amplified by the amplification chambers 55A and 55B to become laser beams LC1 and LC2. According to the laser light source device of FIG. 3A, the near-infrared fundamental wave LA from the fundamental wave generator 56 can be transmitted through the flexible optical fiber 57. The degree of freedom of arrangement is improved. In addition, since the wavelength of the fundamental wave LA output from the fundamental wave generator 56 can be controlled by the structure of the semiconductor laser, the laser light LC1 that is finally output by combination with wavelength conversion in the wavelength converter 58. , LC2 can be easily set to a desired value.

  Further, as shown in FIG. 4, a branching optical system may be disposed between the fundamental wave generator 56 and the wavelength converter. In the laser light source device of FIG. 4, the fundamental wave LA output from the fundamental wave generator 56 passes through a branching optical system including the polarization modulator 52, the PBS 53, and the mirror 54, and is in the same near infrared region as the fundamental wave LA. Are split into laser beams LA1 and LA2. Furthermore, the polarization direction of one laser beam LA2 is rotated by 90 ° by the half-wave plate 61, and the polarization direction becomes the same as that of the laser beam LA1. These laser beams LA1 and LA2 having the same polarization direction are converted into laser beams LB1 and LB2 having a frequency eight times through wavelength converters 58A and 58B having the same configuration as the wavelength converter 58 in FIG. After that, it is amplified by the laser amplification chambers 55A and 55B and outputted as laser beams LC1 and LC2. According to the laser light source device of FIG. 4, since the laser light LA incident on the branching optical system is in the near infrared region, the branching optical system can be easily configured. Furthermore, since the frequencies of the laser beams LA1 and LA2 incident on the wavelength converters 58A and 58B are ½ of the fundamental wave LA incident on the wavelength converter 58 in FIG. 3A, the wavelength converters 58A and 58B. Improves durability.

  In the above embodiment, the emitted two laser beams LC1 and LC2 have the same center wavelength, spectrum width, and oscillation frequency. On the other hand, in applications where it is necessary to independently control the center wavelengths of the two emitted laser beams LC1 and LC2, as shown in FIG. 5, the same as the fundamental wave generator 56 in FIG. What is necessary is just to provide the two fundamental wave generation parts 56A and 56B of a structure. In FIG. 5, the fundamental waves LA1 and LA2 pulsed independently from the fundamental wave generators 56A and 56B are supplied to the wavelength converters 58A and 58B via the optical fibers 57A and 57B, respectively. Then, the laser beams LB1 and LB2 having a frequency 8 times output from the wavelength converters 58A and 58B are amplified in the laser amplification chambers 55A and 55B to become laser beams LC1 and LC2. According to the laser light source device of FIG. 5, the fundamental wave generators 56A and 56B can independently control the oscillation frequencies of the finally output laser beams LC1 and LC2 by controlling the switching frequency of the light modulation elements. .

  In the embodiment shown in FIG. 1, the laser beam LB from the laser light source 50 is branched for each pulse to generate laser beams LB1 and LB2 having a frequency of 1/2. The element 52 is omitted, a half mirror is installed in place of the PBS 53, and the laser beam LB from the laser light source 50 is branched into two laser beams having the same frequency and a pulse energy of ½. Amplification may be performed in the amplification chambers 55A and 55B. In this case, it is necessary to set the oscillation frequency in the laser light source 50 to be equal to or lower than the maximum oscillation frequency of the laser amplification chambers 55A and 55B, but the configuration of the branching optical system is simple, and particularly the electrical optical path. There is an advantage that no switching is required.

In the above-described embodiment, the two laser beams LC1 and LC2 are output in parallel. For example, in FIG. 1, the laser beam LB from the laser light source 50 is used for, for example, a combination of a plurality of beam splitters. It is also possible to output three or more pulsed laser beams in parallel by branching into three or more laser beams using an optical system and amplifying each in a laser amplification chamber similar to the laser amplification chamber 55A. It is.
Alternatively, the two laser beams LC1 and LC2 may be combined coaxially and output. That is, for example, in FIG. 5, the laser beam LC2 output from the laser amplification chamber 55B is bent to the laser beam LC1 side by a mirror (not shown), and the polarization beam splitter (not shown) arranged on the emission side of the laser amplification chamber 55A. The two laser beams LC1 and LC2 may be synthesized coaxially and output. In this case, the oscillation timings of the two laser beams LC1 and LC2 may be different. The oscillation timing may be set to oscillate alternately at substantially equal time intervals. Further, by controlling the oscillation timings in the fundamental wave generators 56A and 56B, the oscillation timings of the two laser beams LC1 and LC2 may be shifted by, for example, the pulse width of each pulse beam. As a result, the peak level of the synthesized laser beam is kept small, and damage to the optical member irradiated with the laser beam is prevented.

[Second Embodiment]
Next, a second embodiment of the laser apparatus of the present invention will be described with reference to FIGS. In this embodiment, the present invention is applied to a laser light source device provided with a pulse stretcher that lowers the peak level of pulsed laser light and widens the pulse width.
FIG. 6 shows an optical system as a light source unit and a pulse stretcher of the laser light source device of this example. The laser light source device of FIG. 6 receives linearly polarized laser beams LC1 and LC2 having substantially the same pulse width and oscillation frequency. Transmits two laser light sources 62A and 62B that emit pulses, a control unit 35B that controls the emission timing and oscillation wavelength of the laser light sources 62A and 62B, and the P-polarized component LC1A of the laser light LC1 output from the laser light source 62A. Then, the first PBS (polarization beam splitter) 63A that reflects and branches the S-polarized component LC1B (first laser beam) and the P-polarized component LC2A of the laser beam LC2 output from the laser light source 62B are transmitted. The second PBS (polarization beam splitter) 63B that reflects and branches the S-polarized component LC2B and the S-polarized light reflected by the PBS 63A Four mirrors 64A to sending to return the minute LC1B to PBS63A, 64B, 64C, and a 64D.

  In this case, the laser beams LC1 and LC2 are incident in parallel with the PBSs 63A and 63B and shifted in the vertical direction with the polarization direction rotated by 45 ° with respect to the incident surface. The amount of light of the polarization component and the reflected S polarization component are substantially equal. The two PBSs 63A and 63B are arranged so that the branch planes are parallel, and the four mirrors 64A to 64D are substantially line-symmetric with respect to the central axes of the laser beams LC1 and LC2, and are S-polarized light. The component LC1B is disposed so as to return to the PBS 63A through an approximately 8-shaped optical path. Then, the S-polarized component LC1B (second laser beam) returned to the PBS 63A is reflected again by the PBS 63A, and then is synthesized coaxially with the P-polarized component LC1A and emitted as a laser beam LD1.

  Further, the S-polarized component LC2B (third laser beam) reflected by the PBS 63B is reflected by the four mirrors 64A to 64D and shifted upward from the S-shaped component LC1B. The optical path is returned to the PBS 63B. The S-polarized component LC2B (fourth laser beam) thus returned is reflected again by the PBS 63B, and then is synthesized coaxially with the P-polarized component LC2A and emitted as the laser beam LD2. As a result, two laser beams LD1 and LD2 that emit pulses are emitted in parallel.

  In this example, if the laser beams LC1 and LC2 output from the laser light sources 62A and 62B are pulsed light indicated by dotted lines in FIG. 7A, the S-polarized components LC1B and LC1B that have passed through the mirrors 64A to 64D in FIG. The delay time of LC2B is set substantially equal to the pulse width of the laser beams LC1 and LC2. As a result, the laser beams LD1 and LD2 synthesized and output from the PBSs 63A and 63B have a peak level of approximately ½ and a pulse width with respect to the laser beams LC1 and LC2, as indicated by solid lines in FIG. Is almost doubled. Therefore, the PBSs 63A and 63B and the mirrors 64A to 64D in this example operate as pulse stretchers for lowering the peak levels of the laser beams LC1 and LC2 and widening the pulse width. As described above, when the laser beams LD1 and LD2 having a reduced pulse level and a wide pulse width are used as exposure light for the exposure apparatus, the illumination optical system and the projection optical system of the exposure apparatus are used. The damage in the optical member can be reduced, or the period until the replacement of the optical member can be increased, and the pulse energy is the same, so the throughput of the exposure process does not decrease. Further, in this example, since the mirrors 64A to 64D in the pulse stretcher are shared by the laser light sources 62A and 62B, the laser light source device can be manufactured at low cost, and the lasers of the two laser beams LD1 and LD2 that are output. There is an advantage that the pulse widths as characteristics can be made almost equal.

  In FIG. 6, as an optical system for transmitting laser light, an optical system consisting of three mirrors or five or more mirrors is used instead of the optical system consisting of four mirrors 64A to 64D. May be. In FIG. 6, even if a beam splitter having a reflectance of approximately ½ is used in place of the PBSs 63A and 63B, the peak levels of the laser beams LD1 and LD2 to be output are substantially halved to reduce the pulse width. It can be almost doubled. Furthermore, as for the pulse width, the full width at half maximum (FWHM) has been conventionally used. However, the light intensity distribution i (t) on the time axis t of the pulse light deviates from the Gaussian distribution. In this case, Tis (total integral square pulse duration) defined by the following equation may be used as an amount representing the pulse width. The symbol ∫ means integration with respect to time t.

Tis = {∫i (t) dt } 2 / {∫i (t) 2 dt} ... (1)
When Tis is used as the pulse width in this way, the pulse stretcher may be configured so that Tis becomes the set target value as an example.
Next, in the embodiment of FIG. 6, the mirrors 64A to 64D may be omitted, the mirror 63C may be disposed instead of the PBS 63B, and the laser beams LC1 and LC2 may be P-polarized light and S-polarized light with respect to the PBS 63A, respectively. In this configuration, the laser light LC1 output from the laser light source 62A passes through the PBS 63A as it is, and the laser light LC2 output from the laser light source 62B is reflected by the mirror 63C and then reflected by the PBS 63A to be combined with the laser light LC1. The laser beam LE is synthesized coaxially. In other words, the mirror 63C and the PBS 63A constitute an optical system that synthesizes the two laser beams LC1 and LC2 coaxially.

  In this case, as shown in FIG. 7B, the control unit 35B in FIG. 6 emits laser light LC1 having a predetermined frequency with a pulse width tp from the laser light source 62B. As shown in FIG. 7C, the laser beam LC1 is delayed by about the pulse width tp with respect to the laser beam LC1, and the laser beam LC2 having the same pulse width, the same peak level, and the same frequency as the laser beam LC1 is pulsed. Make it emit light. As a result, as shown in FIG. 7D, the laser beam LE synthesized by the PBS 63A in FIG. 6 has a pulse width of approximately 2 tp, a peak level that is substantially the same as the laser beam LC1, and a frequency of the laser beam LC1. Will be the same. As described above, in the laser light source device of FIG. 6, the laser beams LC1 and LC2 are coaxially combined, and the laser beam LC2 is emitted by being delayed from the laser beam LC1 by approximately the pulse width tp. Laser light LE that is substantially the same as the light LC1 and LC2 and whose output is twice that of the laser light LC1 and LC2 can be obtained. By using this laser beam LE as exposure light of an exposure apparatus, for example, the throughput of the exposure process can be improved and damage to the optical member can be suppressed.

[Third Embodiment]
Next, a third embodiment of the laser apparatus of the present invention will be described with reference to FIG. In the present embodiment, the present invention is applied to a laser light source apparatus used as an exposure light source of an exposure apparatus. In FIG. 8, parts corresponding to those in FIG. The detailed explanation is omitted.

  FIG. 8 shows an exposure light source 71 and an exposure apparatus main body 72 of this example. In FIG. 8, an exposure light source that generates exposure light IL1 and IL2 in parallel on a floor FL1 of a manufacturing factory for devices such as semiconductor elements. 71 is installed, and an exposure apparatus main body 72 that exposes a substrate such as a wafer through the reticle and the projection optical system with the exposure light IL1 and IL2 is installed on the floor FL2 on the upper surface.

  The exposure light source 71 includes two laser light sources 1A and 1B that independently emit laser light LC1 and LC2, respectively, a beam splitter 65A having a low reflectivity installed on the optical path of one laser light LC1, and the other. A beam splitter 65B having a low reflectivity installed so as to be retractable on the optical path of the laser beam LC2, and center wavelengths, spectrum widths, pulse energy, etc. of a part of the laser beams LC1 and LC2 branched by the beam splitters 65A and 65B Monitor units 66A and 66B for measuring the laser characteristic information of the laser beam, a beam splitter 67 for making a part of the laser beam LC1 incident on the monitor unit 66B on the laser light source 1B side, and a laser beam, A mirror 69 and a movable mirror 70 (for example) that reflect LC1 and LC2 to the exposure apparatus main body 72 side, respectively. If the galvanometer mirror), and a prism 68 for optical path deflecting that is installed to be retracted between the beam splitter 65A and a mirror 69. In this case, the laser light sources 1A and 1B include oscillation laser light sources 50A and 50B each including a laser resonator including a narrowband module LNM and an output mirror OC having the same configuration as the laser light source 50 in FIG. Laser amplification chambers 55A and 55B for amplifying laser beams output from the light sources 50A and 50B and outputting laser beams LC1 and LC2 are provided, and the laser beams LC1 and LC2 are pulsed from the laser light sources 1A and 1B. . Therefore, in this example, the center wavelength, spectrum width, pulse energy, and frequency of the laser beams LC1 and LC2 output in parallel can be controlled independently of each other.

  In addition, a control unit 35A for processing information measured by the monitor units 66A and 66B is provided, and the control unit 35A sets the center wavelengths and spectrum widths of the laser beams LC1 and LC2 from the control system of the exposure apparatus main body 72. Control information such as a target value and a light emission trigger pulse TP indicating the light emission timing of the laser beams LC1 and LC2 are supplied. Based on the control information and the light emission trigger pulse TP, the control unit 35A inserts / removes the beam splitters 65B and 67 and the prism 68 into / from the optical path and drives the movable mirror 70 via a drive mechanism (not shown) as necessary. While controlling the vibration, the pulse light emission operation of the laser light sources 1A and 1B is controlled. In addition, a beam matching unit 73 for transmitting the laser light with a small loss of light amount is installed on the optical path of the laser light LC1, LC2 between the exposure light source 71 and the exposure apparatus main body 72.

  In the light emission operation of the exposure light source 71 in this example, the first light emission mode for supplying the laser beams LC1 and LC2 to the exposure apparatus main body 72 as the exposure beams IL1 and IL2 in parallel, the center wavelengths of the laser beams LC1 and LC2, etc. There are a second light emission mode for performing the above matching and a third light emission mode in which the laser beams LC1 and LC2 are coaxially combined and supplied to the exposure apparatus main body 72 side as the laser light LE. In the first emission mode, the beam splitter 65B is installed in the optical path, the beam splitter 67 and the prism 68 are retracted from the optical path, and the movable mirror 70 is fixed at an angle that reflects the laser beam LC2 to the exposure apparatus main body 72 side. In this state, laser beams LC1 and LC2 are emitted independently from the laser light sources 1A and 1B. At this time, the control unit 35A monitors the center wavelengths and the like of the laser beams LC1 and LC2 via the monitor units 66A and 66B, and the laser light sources 1A and 1B are set so that these center wavelengths and the like become the set target values. Controls the narrowband module LNM.

  On the other hand, in the second light emission mode, in FIG. 8, the control unit 35A causes the laser light sources 1A and 1B to emit pulses with a center wavelength λc and a spectrum width Δλc, respectively. At this time, the measured values (including a predetermined error) of the center wavelength and the spectrum width of the laser light measured by the monitor units 66A and 66B coincide with λc and Δλc, respectively. Next, the control unit 35A retracts the beam splitter 65B to the position P1 outside the optical path, sets the beam splitter 67 to the position P2 on the optical path, and monitors a part of the laser light LC1 output from the laser light source 1A. The light is incident on the part 66B, and the monitor part 66B measures the center wavelength λd and the spectral width Δλd of the laser light LC1. Then, offsets λof and Δλof between the measured values and the previous measured values λc and Δλc are obtained from the following equations and stored in the internal storage unit.

λof = λd−λc, Δλof = Δλd−Δλc (2)
Thereafter, when the first light emission mode is set again and the laser light sources 1A and 1B emit pulses, the control unit 35A sets the first wavelength to the center wavelength and the spectral width of the laser light LC1 measured by the monitor unit 66A. The values obtained by adding the offsets λof and Δλof of the equation (2) obtained in the two emission modes are set as the center wavelength and the spectrum width of the laser light LC1. Thereby, the offset of the measurement values of the monitor units 66A and 66B can be eliminated, and the center wavelengths and spectrum widths of the laser beams LC1 and LC2 output from the exposure light source 71 can be matched. In this case, the measurement value of the monitor unit 66A is calibrated substantially with reference to the monitor unit 66B. Therefore, for example, it is preferable to measure the center wavelength and the spectral width of the laser beam LC2 (exposure light IL2) also on the exposure apparatus main body 72 side and calibrate the measurement value of the monitor unit 66B based on this measurement value. .

  Next, in the third light emission mode, the exposure apparatus main body 72 does not require the two laser beams LC1 and LC2 and follows the optical path of one laser beam (here, referred to as laser beam LC2). Assume that only the laser beam LE is required. The required frequency fne of the laser beam LE is almost twice the upper limit oscillation frequency of the laser light sources 1A and 1B, so that each pulse energy of the laser beam LE does not damage the optical member of the exposure apparatus. Is set to. At this time, the control unit 35A installs the beam splitter 66B in the optical path, retracts the beam splitter 67 outside the optical path, and installs the prism 68 on the optical path. In this state, the laser beam LC1 is deflected toward the movable mirror 70 by the prism 68. Thereafter, the control unit 35A causes the laser light sources 1A and 1B to emit pulses alternately at the oscillation frequency fne / 2, and when the laser beam LC1 is emitted, installs the angle of the movable mirror 70 at a position indicated by a solid line. When the laser beam LC2 is emitted, the angle of the movable mirror 70 is alternately switched so that the angle of the movable mirror 70 is set at the position indicated by the dotted line, and the laser beams LC1 and LC2 are synthesized coaxially to generate the laser beam LE. Generate. The laser beam LE is supplied to the exposure apparatus main body 72 at a frequency fne. In this case, the laser beam LE has a frequency that is approximately twice the maximum oscillation frequency of the laser light sources 1A and 1B, and its output is approximately twice the output of the laser light sources 1A and 1B alone. On the other hand, a high throughput is obtained and each pulse energy is not high, so that the optical member is not damaged.

  In the third light emission mode of the exposure light source 71 in FIG. 8, the laser light source 1B is caused to emit light with a delay of about the pulse width with respect to the laser light source 1A, and the movable mirror 70 is switched in synchronization with this. As shown in FIG. 7D, it is possible to generate a laser beam LE whose pulse width is almost twice that of the laser beams LC1 and LC2 and whose frequency is equal to that of the laser beams LC1 and LC2. The exposure light source 71 of this example has three light emission modes (first, second, and third light emission modes), but may have only two of them, or any one of them. You may have only one. For example, the exposure light source 71 may have only the first light emission mode and the second light emission mode. In this case, the movable mirror 70 may be a fixed mirror without providing the prism 68. Further, the exposure light source 71 may have only the third light emission mode. In this case, without providing the movable mirror 70, for example, the two laser beams LC1 and LC2 may be combined and output coaxially by a polarization beam splitter or the like.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the present invention is applied to a scanning exposure type projection exposure apparatus (exposure apparatus) that performs double exposure. In FIG. 9, parts corresponding to those in FIG. The detailed explanation is omitted.
FIG. 9 shows an exposure apparatus of this example. In FIG. 9, the exposure apparatus includes an exposure light source including laser light sources 1A and 1B, a control unit 35A for controlling pulse emission of the laser light sources 1A and 1B, and a laser. An illumination optical system IU that illuminates the reticle R with exposure light composed of laser light from the light sources 1A and 1B, a reticle stage 22 that moves while holding the reticle R, and an image of a pattern in the illumination area of the reticle R is used as a substrate. Projection optical system PL that projects onto the wafer W coated with the photoresist (photosensitive material), a wafer stage 25 that holds and moves the wafer W, a drive mechanism such as these stages, and a drive mechanism such as these And a main control system 41 composed of a computer that controls the overall operation. As shown in FIG. 8, the laser light sources 1A and 1B are provided with monitor units 66A and 66B (not shown in FIG. 9) for measuring the center wavelength, spectrum width, pulse energy, and the like.

From the exposure light source, ArF excimer laser light (wavelength 193 nm) is supplied. In addition, KrF excimer laser light (wavelength 248 nm), F ₂ laser light (wavelength 157 nm), or the like can also be supplied. In FIG. 9, laser lights LC1 and LC2 pulsed from laser light sources 1A and 1B as exposure light sources are reflected by mirrors 2A and 2B, respectively, and are used as first exposure light IL1 and second exposure light IL2. The light enters the unit 14A and the second lighting unit 14B. Further, the mirror 2A can be retracted to the position P3 by the main control system 41 via a drive unit (not shown), and the mirror 3 having the same reflectance as the mirror 2A is moved by the main control system 41 via the drive unit (not shown). These are arranged so as to be installed at a position P4 between the mirror 2B and the second illumination unit 14B. In this example, the laser light LC1 (first exposure light IL1) can be supplied to the second illumination unit 14B by retracting the mirror 2A at the position P3 and installing the mirror 3 at the position P4 as necessary. It is configured.

  In a normal state in which the mirror 3 is retracted and the mirror 2A is installed on the optical path, the first exposure light IL1 incident on the first illumination unit 14A is a polarization control element 4A (for example, ½ wavelength) that controls the polarization state. It is incident on the optical integrator 6A via a molding optical system 5A that molds the cross-sectional shape of the exposure light to match the incident surface of the subsequent optical integrator. The molding optical system 5A includes, for example, a diffractive optical element (DOE), a zoom lens system, and a pair of prisms (such as an axicon) at least one of which is movable. Although a fly-eye lens is used as the optical integrator 6A, an internal reflection type integrator (such as a rod integrator) or a diffractive optical element may be used instead.

  On the exit surface of the optical integrator 6A, an aperture stop plate 7A of the illumination system is rotatably arranged. Around the rotation axis of the aperture stop plate 7A, a circular aperture stop 7A1 for normal illumination and two eccentrics are arranged. An aperture stop for X-axis dipole illumination composed of a small aperture, an aperture stop 7A3 for Y-axis dipole illumination in a shape obtained by rotating the aperture stop by 90 °, an annular aperture stop for annular illumination, and An aperture stop or the like for a small coherence factor (σ value) is arranged. Then, the main control system 41 rotates the aperture stop plate 7A via the drive motor 8A, so that a desired illumination system aperture stop can be arranged on the exit surface of the optical integrator 6A and corresponding illumination conditions can be set. It is configured as follows.

  The first exposure light IL1 that has passed through the aperture stop on the exit surface of the optical integrator 6A passes through the first relay lens 9A, and then a part of the first exposure light IL1 is branched by the beam splitter 44A to be an integrator sensor 45A composed of a photoelectric detector. The amount of light is measured, and this measured value is supplied to the exposure amount control system 43. The exposure amount control system 43 indirectly monitors the integrated exposure amount at each point on the wafer W from the measured value, and supplies the monitoring result to the main control system 41. Under the control of the main control system 41, the exposure amount control system 43 controls the control unit 35A on the exposure light source side, such as control information such as the center wavelength, spectrum width, and pulse energy of the laser beams LC1 and LC2, and the laser beam. A light emission trigger pulse of LC1 and LC2 is supplied.

  Most of the first exposure light IL1 sequentially enters the fixed blind (fixed field stop) 12A and the movable blind (movable field stop) 10A. The fixed blind 12 </ b> A and the movable blind 10 </ b> A are close to each other and are arranged on a conjugate plane with the pattern surface of the reticle R to be transferred. The fixed blind 12A is a field stop that defines the shape of an illumination area that is elongated in the non-scanning direction on the reticle R, and the movable blind 10A is the first exposure light in an area other than the desired pattern area on the reticle R during scanning exposure. It is driven by the drive mechanism 11A to close the illumination area so that IL is not irradiated. The operation of the drive mechanism 11A is controlled by a reticle stage drive system 42R described later. The movable blind 10A is also used to control the width of the illumination area in the non-scanning direction.

  In this example, as will be described later, the illumination area set by the first illumination unit 14A and the illumination area set by the second illumination unit 14B are combined in the field of view on the pattern surface of the reticle R. The illumination area set on the reticle R by the fixed blind 12A and the movable blind 10A of the unit 14A is called a first illumination slit 10AP, and the reticle is fixed by the fixed blind 12B (described later) and the movable blind 10B (described later) of the second illumination unit 14B. The illumination area set on R is referred to as a second illumination slit 10BP. In a state where the movable blinds 10A and 10B are fully opened, the first illumination slit 10AP and the second illumination slit 10BP in this example are the same region in the field of the projection optical system PL.

The first exposure light IL1 that has passed through the fixed blind 12A and the movable blind 10A passes through the second relay lens 13A and the optical path bending mirror 15A, and is bent at a substantially right angle and enters the field combiner 16. The first illumination unit 14A includes the optical members from the polarization control element 4A to the second relay lens 13A.
On the other hand, the second exposure light IL2 (laser light LC2) incident on the second illumination unit 14B has a polarization control element 4B, a light quantity control member (not shown), and a molding that have the same configuration as the optical members in the first illumination unit 14A. Optical system 5B, optical integrator 6B, aperture stop plate 7B (driven by drive motor 8B), first relay lens 9B, beam splitter 44B (this reflected light is measured via integrator sensor 45B, and this measured value is The light is incident on the second relay lens 13B via the fixed blind 12B and the movable blind 10B (driven by the drive mechanism 11B controlled by the reticle stage drive system 42R). A second illumination unit 14B is configured including optical members from the polarization control element 4B to the second relay lens 13B. The second exposure light IL2 that has passed through the second relay lens 13B is incident on the field synthesizer 16 with its optical axis shifted in parallel through the optical path bending mirrors 15B and 15C. When the field synthesizer 16 is a polarization beam splitter (PBS), the first exposure light IL1 and the second exposure light IL2 are incident on the field synthesizer 16 as S-polarized light and P-polarized light by the polarization control elements 4A and 4B, respectively. And are synthesized coaxially. When the field synthesizer 16 is a half mirror, the output decreases to ½, but the first exposure light IL and the second exposure light IL2 can be irradiated onto the reticle R in a desired polarization state.

  That is, the first exposure light IL1 and the second exposure light IL2 emitted from the field synthesizer 16 are synthesized coaxially. As described above, the first lighting unit 14A and the second lighting unit 14B have the same configuration, but the movable blinds 10A and 10B are driven independently of each other. Therefore, the shape of the illumination area (first illumination slit 10AP) of the first exposure light IL1 set on the reticle R by the blinds 12A and 10A of the first illumination unit 14A, and the blinds 12B and 10B of the second illumination unit 14B. The shape of the illumination area (second illumination slit 10BP) of the second exposure light IL2 set on the reticle R can be set independently of each other. Further, the aperture stop plates 7A and 7B are also driven independently of each other. Therefore, the illumination condition in the first illumination slit 10AP set by the first illumination unit 14A and the illumination condition in the second illumination slit 10BP set by the second illumination unit 14B can be set independently of each other. .

  The exposure lights IL1 and IL2 synthesized by the field synthesizer 16 pass through a mirror 17, a first condenser lens 18, a mirror 19 that bends the optical path substantially vertically downward, and a second condenser lens 20 through a reticle. Illumination slits 10AP and 10BP in the pattern area provided on the R pattern surface (lower surface) are illuminated with a uniform illuminance distribution. The mirrors 15A to 15C, the field synthesizer 16, the mirrors 17 and 19, and the condenser lenses 18 and 20 constitute a field synthesis optical system. The field synthesis optical system, the first illumination unit 14A, and the second An illumination optical system IU is configured including the illumination unit 14B.

  Under the exposure light IL1 and IL2, the pattern in the illumination slits 10AP and 10BP of the reticle R is a photoresist with a predetermined projection magnification β (β is 1/4, 1/5, etc.) via the projection optical system PL. Is projected onto the projection area 21W on the wafer W to which the coating is applied. As the projection optical system PL, in addition to the refractive system, for example, as disclosed in Japanese Patent Application Laid-Open No. 2001-249286, an optical system having an optical axis from the reticle to the wafer, and substantially orthogonal to the optical axis. A catadioptric system having an optical axis that forms an intermediate image twice, or disclosed in, for example, International Publication No. 2004/107011 (corresponding to US Publication No. 2006/0121364) As described above, an optical system (reflection system or reflex system) that has a plurality of reflecting surfaces and forms an intermediate image at least once is provided in a part thereof, and has a single optical axis. An inline catadioptric system or the like can also be used.

  The projection optical system PL of this example is a refraction system, and its effective field on the object plane side is a circular area centered on the optical axis AX, and the areas when the illumination slits 10AP and 10BP are maximized are the respective light beams. This is a rectangular area that is elongated in the Y direction and is substantially inscribed in the circular area (the outline of the effective field of view) about the axis AX. Here, a common area when the illumination slits 10AP and 10BP are maximized is referred to as a field of view of the projection optical system PL (field of view on the object plane side). Hereinafter, the Z axis is taken in parallel to the optical axis AX of the projection optical system PL, and along the scanning direction of the reticle R and the wafer W during scanning exposure (a direction parallel to the paper surface of FIG. 9) in a plane perpendicular to the Z axis. In the following description, the Y axis is taken and the X axis is taken along the non-scanning direction (direction perpendicular to the paper surface of FIG. 9) perpendicular to the scanning direction.

  First, the reticle R is sucked and held on the reticle stage 22, and the reticle stage 22 is placed on the reticle base 23 so as to be continuously moved in the Y direction by a linear motor or the like. Further, the reticle stage 22 incorporates a mechanism for finely moving the reticle R in the X direction, the Y direction, the rotation direction around the Z axis, and the like. The position of the reticle stage 22 (reticle R) in at least the X direction and the Y direction, and the rotation angle around the Z axis are the movable mirror 26R (or a reflecting surface) on the reticle stage 22 and the opposite to the movable mirror 26R. Measurement is performed with high accuracy by a laser interferometer 27 </ b> R in which a part is arranged, and the reticle stage drive system 42 </ b> R controls the operation of the reticle stage 22 based on the measurement result and control information from the main control system 41. The reticle stage drive system 42R also opens / closes the movable blinds 10A and 10B via the drive mechanisms 11A and 11B based on the position information of the reticle stage 22 (and thus the reticle R) in the Y direction (scanning direction). The width in the Y direction of each of the first illumination slit 10AP and the second illumination slit 10BP is controlled.

Note that the opening / closing operation of the movable blinds 10A and 10B may be controlled by a control device provided independently of the reticle stage drive system 42R.
On the other hand, the wafer W is sucked and held on the wafer stage 25 via a wafer holder (not shown), and the wafer stage 25 includes a Z tilt stage for controlling the focus position (position in the Z direction) and the tilt angle of the wafer W, linear The XY stage is configured to move continuously in the Y direction on the wafer base 30 by a motor or the like and move stepwise in the X direction and the Y direction. The position of the wafer stage 25 (wafer W) in at least the X direction and the Y direction, and the rotation angle around the Z axis are the moving mirror 26W (or a reflecting surface) on the wafer stage 25 and the opposite of the moving mirror 26W. The wafer stage drive system 42W controls the operation of the wafer stage 25 based on the measurement result and the control information from the main control system 41.

  During normal scanning exposure, the wafer W is projected through the wafer stage 25 in synchronization with the movement of the reticle R through the reticle stage 22 in the Y direction with respect to the illumination slits 10AP and / or 10BP at a speed VR. By moving at a speed β · VR (β is the projection magnification from the reticle R to the wafer W) in the Y direction with respect to 21W, a pattern image in a series of two pattern areas (details will be described later) of the reticle R is changed to the wafer W. The image is sequentially transferred to the shot areas adjacent in the upper two scanning directions. Thereafter, the wafer stage 25 is moved stepwise to move the next shot area on the wafer to the scanning start position, and the above scanning exposure is repeated by the step-and-scan method. Exposure is sequentially performed for every two shot areas adjacent in the scanning direction. Thereafter, with the wafer W shifted in the Y direction by the width of one shot area, the image of the pattern of the reticle R is sequentially exposed to two adjacent shot areas on the wafer W by the above step-and-scan method. Thus, double exposure is performed on each shot area on the wafer W.

  If this exposure is a superposition exposure, it is necessary to align the reticle R and the wafer W in advance. Therefore, a reference mark member (not shown) in which a reference mark is formed in the vicinity of the wafer on the wafer stage 25 is fixed, and the position of the alignment mark attached to each shot area on the wafer W on the side surface of the projection optical system PL. An image processing type alignment sensor 36 for detecting the above is installed. In addition, in order to measure the position of the alignment mark on the reticle R above the reticle stage 22, a pair of alignment systems 34A and 34B of an image processing system are installed. The alignment systems 34A and 34B are actually arranged above both ends of the illumination slits 10AP and 10BP in the X direction (non-scanning direction). The detection results of the alignment sensor 36 and alignment systems 34A and 34B are processed by an alignment control system (not shown). The alignment sensor 36 and the alignment systems 34A and 34B are not limited to the image processing system, and may be a system that detects diffracted light generated from the mark by irradiation with a coherent beam, for example.

  An irradiation amount monitor 46 for measuring the energy of the exposure light IL1 and IL2 is installed in the vicinity of the wafer W on the wafer stage 25, and the measurement value of the irradiation monitor 46 is supplied to the exposure amount control system 43. . Further, in the vicinity of the wafer W on the wafer stage 25, the exposure light IL1 and IL2 having a surface having the same height as the surface of the wafer W and slits parallel to the X axis and the Y axis formed on the surface are transmitted. The condensing lens 47 and the photoelectric detector 48 are installed in the wafer stage 25 on the bottom surface of the slit plate 29, and the detection signal of the photoelectric detector 48 is supplied to the exposure amount control system 43. Yes. Usually, for example, a test reticle having a line and space pattern (hereinafter referred to as an L & S pattern) formed at a predetermined pitch in the Y direction (or X direction) on the reticle stage 22 is loaded, and projection optics for the L & S pattern is used. The operation of scanning the image by the system PL in the Y direction with the slit plate 29 and detecting the contrast of the detection signal output from the photoelectric detector 48 changes the position (focus position) of the wafer stage 25 in the Z direction. By repeating this, the best focus position of the projection optical system PL can be obtained from the focus position of the wafer stage 25 when the contrast is highest.

  Furthermore, in this example, in order to calibrate the wavelengths of the exposure lights IL1, IL2 (laser lights LC1, LC2), the illumination optical system IU is irradiated with only the first exposure light IL1 (laser light LC1), An operation of scanning the image of the L & S pattern of the above test reticle by the projection optical system PL in the Y direction with the slit plate 29 and detecting the contrast of the detection signal output from the photoelectric detector 48 is performed on a plurality of wafer stages 25. By repeating at the focus position, the best focus position FZ1 of the projection optical system PL is obtained. Next, in a state where only the second exposure light IL2 (laser light LC2) is irradiated onto the illumination optical system IU, the image of the L & S pattern by the projection optical system PL is scanned by the slit plate 29 in the Y direction, thereby projecting. The best focus position FZ2 of the optical system PL is obtained. In this case, the difference ΔZF (= FZ2−FZ1) between the best focus positions FZ1 and FZ2 obtained by two measurements can be regarded as a function of the difference Δλ between the center wavelengths λ1 and λ2 of the laser beams LC1 and LC2.

  Therefore, a table indicating the relationship between the difference ΔZF and the difference Δλ is obtained in advance by computer simulation or the like and stored in the storage unit in the main control system 41, and at the time of calibration of the wavelengths of the laser beams LC1 and LC2, By measuring the difference ΔZF of the best focus position, the wavelength difference Δλ of the laser beams LC1 and LC2 can be obtained from the table. Information on the wavelength difference Δλ of the laser beams LC1 and LC2 measured in this way is supplied to the control unit 35A. In the control unit 35A, for example, the wavelength of one laser beam LC2 is measured with high accuracy by the measurement value of the attached monitor unit, and the wavelength of the laser beam LC2 is corrected by the difference Δλ. The wavelength of the other laser beam LC1 can be accurately obtained.

Hereinafter, an example of the double exposure operation of this example will be described. On the pattern surface of the reticle R of this example, two pattern regions (transfer patterns) for double exposure are formed along the scanning direction.
FIG. 10 is a plan view showing the pattern arrangement of the reticle R used in this example. In FIG. 10, the region surrounded by the rectangular frame-shaped light shielding band 81 of the reticle R has two regions in the Y direction. The pattern is divided into first and second pattern areas 82A and 82B having the same size, and different transfer patterns (hereinafter referred to as patterns A and B, respectively) are drawn in the pattern areas 82A and 82B. The patterns A and B are patterns generated from a circuit pattern transferred to one layer of each shot area on the wafer W, and correspond to the circuit patterns by exposing the images of the patterns A and B in an overlapping manner. A projected image is exposed in each shot area. As an example, the pattern A in the first pattern area 82A is composed of the L & S pattern 85Y in the Y direction arranged at a pitch about the resolution limit in the Y direction, and the pattern B in the second pattern area 52B is X The L & S pattern 85X in the X direction is arranged in the direction at a pitch about the resolution limit.

  In this example, the pattern B in the first pattern area 82A and the second pattern area 82B is transferred by the first illumination slit 10AP and the second illumination slit 10BP in FIG. In the illumination unit 14A, the Y-axis aperture stop 7A3 (having two secondary light sources separated in the Y direction) for the Y-direction L & S pattern 85Y is selected, and in the second illumination unit 14B, the X-direction aperture stop 7A3 is selected. The aperture stop 7B2 for dipole illumination (with two secondary light sources separated in the X direction) for the L & S pattern 85X is selected. In this case, the illumination slits 10AP and 10BP are illuminated with two-pole illumination orthogonal to each other. For example, when the pattern A is a periodic pattern and the pattern B is an isolated pattern, as an example, the illumination condition of the first illumination slit 10AP is the annular illumination, and the illumination condition of the second illumination slit 10BP is Small σ illumination may be used. Further, when the visual field synthesizer 16 of FIG. 9 is a half mirror, it is possible to optimize the polarized illumination for each of the pattern regions 52A and 52B.

  Further, the size of the pattern areas 82A and 82B of the reticle R in FIG. 10 corresponds to the size of one shot area on the wafer W, and the light shielding band 83 at the boundary between the pattern areas 82A and 82B It has a width corresponding to the width of the adjacent street line on W. That is, an image obtained by reducing the two pattern areas 82A and 82B with the projection magnification of the projection optical system PL corresponds to the size of two shot areas adjacent in the scanning direction on the wafer W. If the width of the street line on the wafer W is 100 μm and the magnification of the projection optical system PL is ¼, the width of the light shielding band 83 is 400 μm. With such a width, the first illumination slit 10AP (or the second illumination slit 10BP) can move to the second pattern region 82B (or the second illumination slit 10BP) even if there is a slight positioning error in the edge portions of the movable blinds 10A and 10B in FIG. Alternatively, it is possible to prevent the first pattern region 82A) from being irradiated.

Further, a pair of alignment marks 84A and 84B are formed so as to sandwich the pattern area of the reticle R in the X direction, and the positions of these alignment marks 84A and 84B are measured by the alignment systems 34A and 34B in FIG. Thus, alignment of the reticle R can be performed.
Next, the pattern A image of the first pattern area 82A of the reticle R in FIG. 10 and the pattern B of the second pattern area 82B in two shot areas adjacent to each other in the Y direction on the wafer W in FIG. The image is exposed with a single scanning exposure. Thereafter, the second position of reticle R in FIG. 10 is shifted to two shot areas adjacent in the Y direction on wafer W (however, the position in the Y direction is shifted by one shot area from the time of the first exposure). The pattern A image and the pattern A are formed on each shot area on the wafer W by exposing the pattern A image of the first pattern area 82A and the pattern B image of the second pattern area 82B by one scanning exposure. The image of B is double exposed. Thereafter, the photoresist on the wafer W is developed and etched to form a circuit pattern corresponding to a pattern in which the patterns A and B are superimposed on each shot area on the wafer W. As described above, according to the double exposure method of this example, two circuit patterns can be exposed to each shot area on the wafer W under optimum illumination conditions, and adjacent to each other on the wafer W by one scanning exposure. Since two shot areas can be exposed, a highly functional device can be manufactured with high throughput and high accuracy.

Next, an example of the calibration operation of the two integrator sensors 45A and 45B of the exposure apparatus of FIG. 9 will be described with reference to the flowchart of FIG. The entire operation below is controlled by the main control system 41.
First, in step 101 of FIG. 11, a reticle having no pattern is loaded on the reticle stage 22 of FIG. 9, the movable blinds 10A and 10B in the illumination optical system IU are fully opened, and the projection of the projection optical system PL is performed. The dose monitor 46 on the wafer stage 25 is moved into the region 21W (not yet exposed to the exposure light IL1 and IL2). Next, the exposure amount control system 43 sets the output (product of pulse energy and frequency) of the laser light source 1A to the median value E1 within the variable range (step 102), the mirror 2A is installed on the optical path, and the first The optical path of the laser light LC1 (first exposure light IL1) from the laser light source 1A is set in one illumination unit 14A (step 103). In the next step 104, the laser light source 1A is caused to emit light at its median value E1, and the measured value IU1 of the integrator sensor 45A and the measured value S1 of the dose monitor 46 are stored.

  Next, the mirror 2A is retracted to the position P3, the mirror 3 is set to the position P4 on the optical path, and the optical path of the laser light LC1 (first exposure light IL1) from the laser light source 1A is set to the second illumination unit 14B. After that (step 105), the laser light source 1A is caused to emit light at its median value E1, and the measured value IU2 of the integrator sensor 45B and the measured value S2 of the irradiation amount monitor 46 are stored (step 106). In the next step 107, the exposure amount control system 43 uses the measurement values in steps 104 and 106, and the error ΔIU of the measurement values of the integrator sensors 45A and 45B and the fluctuation amount of the measurement value of the irradiation amount monitor 46 as follows. ΔS is calculated.

ΔIU = (IU2 / IU1-1) × 100 (%) (3)
ΔS = (S2 / S1-1) × 100 (%) (4)
Further, the exposure amount control system 43 calculates the error coefficient ΔPL as follows using the error ΔIU and the variation amount ΔS.
ΔPL = ΔS / ΔIU (5)
Thereafter, as an example, the offset or gain of the integrator sensor 45B on the second lighting unit 14B side may be adjusted so as to correct the error ΔIU. Thereby, the measurement values of the two integrator sensors 45A and 45B can be matched with the common laser beam LC1 as a reference. Further, for example, when the error coefficient ΔPL is greatly deviated from a predetermined value, the illumination optical system IU may be adjusted.

  Next, an example of a method for determining the oscillation frequency of the laser light sources 1A and 1B as exposure light sources in the exposure apparatus of FIG. 9 will be described with reference to the flowchart of FIG. This operation is executed in the main control system 41. In this case, since the pulsed laser beam has energy variations from pulse to pulse, the minimum number of exposure pulses Nmin required to equalize the integrated exposure amount at each point on the wafer W and the number of exposure pulses beyond that are increased. However, the maximum exposure pulse number Nmax that does not substantially change the uniformity of the integrated exposure amount is determined in advance and stored in the storage unit in the main control system 41. Further, the appropriate exposure amounts for the photoresist on the wafer W for exposing the patterns of the two pattern regions 82A and 82B on the reticle R in FIG. 10 are Dose1 and Dose2, respectively. The laser light LC1 from the laser light source 1A and the laser light LC2 from the laser light source 1B are used for the exposure of the pattern regions 82A and 82B, respectively. Further, the maximum oscillation frequency of the laser light sources 1A and 1B is approximately fmax, and the pulse energies of the laser beams LC1 and LC2 are Pe1 and Pe2 (the median values thereof are Pe10 and Pe20), respectively.

First, in order to determine the oscillation frequency f1 and the like of the first laser light source 1A, in step 110 in FIG. 12, each point on the wafer W is set with laser light LC1 (exposure light IL1) of pulse energy Pe10 from the laser light source 1A. The number of exposure pulses N1max necessary for exposure with the appropriate exposure dose Dose1 is obtained from the following equation.
N1max = Dose1 / Pe10 (6)
Next, it is determined whether or not the calculated exposure pulse number N1max is smaller than the minimum exposure pulse number Nmin (step 111). When N1max is smaller than Nmin, the operation proceeds to step 112, and the exposure pulse number is the minimum. The oscillation frequency f1 of the laser light source 1A is calculated from the following equation using the Nmin so that the exposure pulse number Nmin. Note that the scanning speed (the initial value is, for example, the maximum value) in the Y direction of the wafer stage 25 is Vw, and the width in the Y direction (slit width) when the projection area 21W is fully opened is Sw. Therefore, Sw / Vw is the time (exposure time) required for each point on the wafer W to cross the projection area 21W in the scanning direction, and the number of pulses per unit time is obtained by dividing the number of exposure pulses by the exposure time. That is, the oscillation frequency is obtained.

f1 = Nmin / (Sw / Vw) = Nmin · Vw / Sw (7)
Further, the pulse energy Pe1 at this time is changed to Dose1 / Nmin. Note that when the frequency f1 calculated by the equation (7) exceeds the maximum frequency fmax, the scanning speed Vw may be lowered.
On the other hand, when N1max is equal to or greater than Nmin in step 111, the routine proceeds to step 113, where it is determined whether N1max is smaller than the maximum exposure pulse number Nmax. When N1max is smaller than Nmax, N1max can be used as it is as the number of exposure pulses of the laser beam LC1. Therefore, the process proceeds to step 114, and the oscillation frequency of the laser light source 1A is calculated from the following equation corresponding to equation (7) using N1max. Calculate f1. The pulse energy Pe1 at this time may be the initial value Pe10.

f1 = N1max Vw / Sw (8)
If N1max is greater than or equal to Nmax in step 113, the process proceeds to step 115 where the oscillation frequency f1 of the laser light source 1A is set to the maximum value fmax, and the number of exposure pulses is set to Nmax in accordance with this. The scanning speed V1 of the wafer stage 25 is calculated from the following equation. The pulse energy Pe1 at this time is Dose1 / Nmax.

V1 = fmax · Sw / Nmax (9)
Next, when determining the oscillation frequency f2 and the like of the second laser light source 1B, the number of exposure pulses N1max, the appropriate exposure dose Dose1, and the pulse energy Pe10 in equation (6) are replaced with N2max, Dose2, and Pe20, respectively. Twelve steps 110 to 115 may be executed. However, on the laser light source 1B side, the scanning speed V2 of the wafer stage 25 uses the scanning speed V1 (or Vw) optimized for the laser light source 1A as it is. Therefore, in the case of the laser light source 1B, corresponding to step 115 in FIG. 12, as shown in step 115A, the scanning speed V2 of the wafer stage 25 is V1, and the oscillation frequency f2 of the laser light source 1B is near the maximum frequency fmax. Then, the pulse energy Pe2 of the laser beam LC2 may be calculated from the following equation. In this case, the number of exposure pulses N2 for the wafer W by the laser beam LC2 may be slightly different from Nmax.

V1 = f2 · Sw / N2 (10)
Pe2 = Dose2 / N2 (11)
As described above, according to the exposure apparatus of FIG. 9 of this example, the calibration of the integrator sensors 45A and 45B can be easily performed by causing one laser beam LC1 to alternately enter the illumination units 14A and 14B. Can do. Further, since the oscillation frequency and pulse energy of the laser light sources 1A and 1B are determined so that the number of exposure pulses is within an appropriate range, the uniformity of the integrated exposure amount on the wafer W is improved. Further, by adjusting the oscillation frequency and pulse energy on the second laser light source 1B side, the scanning speed of the wafer stage 25 can be optimized in common for the two laser beams LC1 and LC2.

  In the present embodiment, the laser light sources 1A and 1B of the exposure light source 71 in FIG. 8 are used. However, the exposure light source is not limited to this, and for example, the laser light source device of the first or second embodiment may be used. Good. Further, in the present embodiment, the aperture diaphragm plates 7A and 7B may not be provided in the first and second illumination units 14A and 14B, respectively. For example, as disclosed in US Patent Publication No. 2006/0170901, etc. The shaping optical systems 5A and 5B may change the polarization states of the exposure lights IL1 and IL2, respectively. Further, in this embodiment, the illumination optical system IU includes the first and second illumination units 14A and 14B on which the laser beams LC1 and LC2 are incident, respectively, but the first and second illumination units 14A and 14B are provided. Alternatively, the laser beams LC1 and LC2 may be incident on a common illumination unit.

  In the present embodiment, the first illumination area 10AP and the second illumination area 10BP are disposed on the reticle R with respect to the scanning direction (Y direction). However, the first illumination area 10AP and the second illumination area are arranged. At least a part of 10BP may overlap. Furthermore, in the present embodiment, the reticle on which the two patterns A and B are formed is used, but different reticles on which the patterns A and B are formed may be used. In this case, the two reticles may be held on the same reticle stage or on different reticle stages.

In the exposure light source of FIG. 9, laser light sources 1A and 1B including the oscillation laser light source and laser amplification chamber of FIG. 8 are used, but each of the laser light sources 1A and 1B is a conventional one. A laser light source having a structure in which a discharge chamber is sandwiched between laser resonators can be used. Further, as the laser light sources 1A and 1B, it is obvious that a laser light source or the like that converts the wavelength of laser light from a solid-state laser light source (semiconductor laser or the like) by a wavelength conversion unit can be used.
In each of the above embodiments, the laser light source device (exposure light source) is a MOPA laser system. However, each of the laser amplification chambers 55A and 55B includes an optical output amplifier (Power Oscillator (PO)) having a laser resonator. It may be a MOPO laser system (ie, an injection locking system).

  In the exposure apparatus of the above-described embodiment, a light transmission type reticle (mask) in which a predetermined light shielding pattern (or phase pattern / dimming pattern) is formed on a light transmissive substrate is used. Instead of the mask, for example, as disclosed in US Pat. No. 6,778,257, 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 is used. May be. This electronic mask is also called a variable shaping mask, and includes, for example, a DMD (Digital Micro-mirror Device) which is a kind of non-light emitting image display element (spatial light modulator).

  In the exposure apparatus of the above-described embodiment, the wafer is exposed by projecting a pattern image onto the wafer using the projection optical system PL, which is disclosed in International Publication No. 2001/035168. As described above, the present invention can be applied to an exposure light source of an exposure apparatus (lithography system) that exposes lines and spaces on a substrate by forming interference fringes on the substrate.

Furthermore, the laser light source device of the present invention (such as the laser light source device of FIG. 1) can also be used as a light source for laser processing devices other than the exposure device.
Further, when a semiconductor device is manufactured using the exposure apparatus of the above-described embodiment, the semiconductor device includes a step of designing a function and performance of the device, a step of manufacturing a reticle based on this step, and a wafer from a silicon material. Forming, aligning with the exposure apparatus of the above embodiment to expose the reticle pattern onto the substrate (wafer), developing the exposed substrate, heating (curing) the developed substrate, and etching. It is manufactured through a substrate processing step, a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like.

  Further, the present invention is not limited to application to a semiconductor device manufacturing process, for example, a manufacturing process of a display device such as a liquid crystal display element formed on a square glass plate or the like, or a plasma display, or imaging. The present invention can be widely applied to manufacturing processes of various devices such as devices (CCD, etc.), micromachines, MEMS (Microelectromechanical Systems), thin film magnetic heads using ceramic wafers as substrates, and DNA chips. Furthermore, the present invention can also be applied to a manufacturing process when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

  In addition, this invention is not limited to the above-mentioned embodiment, A various structure can be taken in the range which does not deviate from the summary of this invention.

  According to the laser device that outputs two laser beams of the present invention, the two laser beams can be output in a state where characteristics such as the center wavelength are substantially equal, or the laser device can be configured at low cost. Therefore, by performing exposure by the double exposure method using the laser device, the imaging characteristics can be improved, or the exposure light source can be configured at low cost. Therefore, a highly functional device can be manufactured with high accuracy or at low cost.

It is a figure which shows the structure of the laser light source apparatus of 1st Embodiment. It is a figure which shows the relationship between the several signal in FIG. 1, and the several laser beam output. (A) is a figure which shows the modification which replaced the laser light source 50 of FIG. 1 with another light source, (B) is a figure which shows the structure of the wavelength conversion part 58 in FIG. 3 (A). It is a figure which shows another modification of the laser light source apparatus of FIG. It is a figure which shows the modification of the laser light source apparatus of FIG. It is a perspective view which shows the structure of the laser light source apparatus of 2nd Embodiment. It is a figure which shows the change of the pulse width of the laser beam in FIG. It is the figure which notched the part which shows the exposure light source and exposure apparatus main-body part of 3rd Embodiment. It is the figure which notched the part which shows the structure of the exposure apparatus of 4th Embodiment. FIG. 10 is a plan view showing a pattern arrangement of a reticle R in FIG. 9. 10 is a flowchart showing an example of calibration of the integrator sensor of the exposure apparatus in FIG. 9. 10 is a flowchart illustrating an example of a method for calculating an oscillation frequency of a laser light source of the exposure apparatus in FIG.

Explanation of symbols

  R ... reticle, PL ... projection optical system, W ... wafer, 1A, 1B ... laser light source, 14A, 14B ... illumination unit, 35, 35A, 35B ... control unit, 45A, 45B ... integrator sensor, 50, 50A, 50B ... Laser light source for oscillation, LNM ... narrow band module, OC ... output mirror, 52 ... polarization modulator, 53 ... polarization beam splitter, 55A, 55B ... laser amplification chamber, 56, 56A, 56B ... fundamental wave generator, 58 58A, 58B ... wavelength conversion unit, 62A, 62B ... laser light source, 64A to 64D ... mirror, 66A, 66B ... monitor unit, 70 ... movable mirror

Claims (22)

A laser device that outputs two laser beams,
A first laser light source having a first wavelength selection optical system for controlling the wavelength of the laser light, and emitting a pulse of the first laser light;
A second laser light source having a second wavelength selection optical system for controlling the wavelength of the laser light, and emitting a pulse of the second laser light;
A wavelength monitor for measuring the wavelength information of the laser beam;
An optical path switching optical system for selectively guiding one of the first and second laser beams to the wavelength monitor;
Based on wavelength information of the first and second laser beams measured by the wavelength monitor, the wavelengths of the first and second laser beams are controlled via the first and second wavelength selection optical systems. And a control system.   2. The laser device according to claim 1, wherein the control system adjusts the wavelength of one of the first and second laser beams to the wavelength of the other laser beam. 3. A laser device that outputs two laser beams,
First and second laser light sources each emitting pulsed laser light;
A first branching / synthesizing optical system for branching the first laser beam from the laser beam output from the first laser light source and for combining and outputting the second laser beam;
A second branching / synthesizing optical system for branching the third laser light from the laser light output from the second laser light source and for combining and outputting the fourth laser light;
The first laser beam is guided to the first branch optical system as the second laser beam, and the third laser beam is guided to the second branch optical system as the fourth laser beam. With an optical system,
A laser apparatus characterized in that two laser beams are output in parallel from the first and second branching / combining optical systems. The first and second branching and combining optical systems are two beam splitters arranged in parallel,
The light transmitting optical system is
A first mirror that reflects the first and third laser beams;
The first and third laser beams, which are arranged substantially symmetrically with the first mirror so as to sandwich the two beam splitters and are reflected by the first mirror, are respectively the second and fourth laser beams. The laser device according to claim 3, further comprising a second mirror that reflects the laser beam. A laser device that outputs two laser beams,
A laser light source that emits pulsed laser light;
A branching optical system for outputting the laser light output from the laser light source as first and second laser lights having different optical paths alternately for each pulse;
A laser apparatus comprising: first and second laser amplifiers that amplify and output the first and second laser beams in parallel, respectively. The branch optical system is:
A light modulation element that alternately converts the polarization state of the laser light output from the laser light source into first and second polarization states for each pulse;
6. The laser apparatus according to claim 5, further comprising a polarization beam splitter that outputs the light in the first and second polarization states as the first and second laser lights, respectively. The laser light source is
The laser apparatus according to claim 6, further comprising: a solid-state laser light source; and a wavelength conversion unit that converts the wavelength of the laser light emitted from the solid-state laser light source into a short wavelength. The laser light source is a solid-state laser light source that emits infrared laser light,
The first and second wavelength converters are disposed between the branch optical system and the first and second laser amplifiers, respectively, for converting the wavelength of the laser light into an ultraviolet region. The laser device according to claim 6.   9. The laser apparatus according to claim 1, wherein the two laser beams are combined and output substantially coaxially.   9. The laser apparatus according to claim 1, wherein the two laser beams are independently output. A laser device that emits a pulse of laser light,
First and second laser light sources each emitting pulsed laser light;
A synthesis optical system for synthesizing laser beams from the first and second laser light sources substantially coaxially;
A laser apparatus comprising: a control system that causes the first and second laser light sources to emit light at the same pulse frequency and with a time difference substantially corresponding to the emission time of each pulsed light. In an exposure method of moving the substrate in the corresponding second direction in synchronization with the movement of the pattern in the first direction while the substrate is exposed through the pattern and the projection optical system with an exposure beam,
Two laser lights output in parallel from the laser device according to any one of claims 1 to 10 are used as first and second illumination lights,
First and second pattern regions are formed on the pattern adjacent to the first direction,
When the pattern is moved in the first direction and the first pattern area passes through the field of view of the projection optical system, the first illumination area having a variable width in the first direction is used. Illuminating the first pattern area with one illumination light to expose the substrate;
When the second pattern region passes through the field of view, the second pattern region is illuminated with the second illumination light using the second illumination region having a variable width in the first direction, and the substrate An exposure method characterized by exposing. Illuminating the first and second illumination areas with one of the first and second illumination lights;
Monitoring light quantity information of illumination light that illuminates the first and second illumination areas;
13. The exposure method according to claim 12, wherein calibration of the monitor result of the illumination light that illuminates the first and second illumination areas is performed based on the monitor result. In order to independently control the light amounts of the first and second illumination lights that illuminate the first and second illumination areas,
14. The exposure method according to claim 12, wherein at least one of a pulse frequency and pulse energy of two laser beams output from the laser device is independently controlled. Measuring the best focus position of the image by the first and second illumination light on the image plane side of the projection optical system;
The exposure method according to any one of claims 12 to 14, wherein a wavelength difference between the first and second illumination lights is controlled based on the measurement result. In an exposure apparatus that moves the substrate in the corresponding second direction in synchronization with the movement of the pattern in the first direction in a state where the substrate is exposed through the pattern and the projection optical system with illumination light,
A laser device according to any one of claims 1 to 10,
Illuminating the first illumination region having a variable width in the first direction within the field of view of the projection optical system with the first illumination light composed of one laser beam output from the laser device, and the first region within the field of view An illumination optical system that illuminates a second illumination region having a variable width in one direction with a second illumination light composed of the other laser light output from the laser device;
An exposure apparatus comprising: an illumination control device that controls a width of the first and second illumination regions in the first direction according to a position of the pattern in the first direction. The illumination optical system includes:
A first partial illumination system that illuminates a region conjugate with the first illumination region;
A second partial illumination system that illuminates a region conjugate with the second illumination region;
17. The exposure apparatus according to claim 16, further comprising: a field synthesis system that illuminates the pattern by synthesizing illumination light from the first and second partial illumination systems. A light amount monitor provided in the first and second partial illumination systems for measuring light amount information of the first and second illumination lights, respectively;
18. The exposure apparatus according to claim 17, further comprising: an optical path switching optical system that simultaneously guides one of the two laser beams from the laser apparatus to the first and second partial illumination systems. An exposure monitor for measuring light quantity information of the first and second illumination lights on the image plane of the projection optical system;
17. An exposure amount control system for controlling at least one of pulse frequency and pulse energy of two laser beams output from the laser device based on a measurement result of the exposure amount monitor. The exposure apparatus according to claim 18.   20. The measurement apparatus according to claim 16, further comprising a measurement device that measures a best focus position of an image formed by the first and second illumination lights on an image plane of the projection optical system. The exposure apparatus described. In an exposure apparatus that exposes a substrate with illumination light through an optical member,
A laser device according to any one of claims 1 to 11, comprising:
An exposure apparatus using laser light from the laser device as the illumination light.   A device manufacturing method using the exposure method according to any one of claims 12 to 15.

Images