JP2008122785A - Laser device, excimer laser device, light irradiation device, exposure device, light generation method, light irradiation method, exposure method, and method for manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser device that can stably emit a laser beam at a target wavelength. <P>SOLUTION: Since a wavelength conversion unit 160 has a set of wavelength conversion elements 167d, 167e disposed without mediating a multiplexing optical element such as a dichroic mirror therebetween in the last stage of the unit, it is not necessary to consider positioning of the multiplexing optical element or degradation of the multiplexing optical element due to irradiation with a laser beam. Consequently, even when power of laser beams L1 to L4 generated in a laser light source is increased, a laser beam at a target wavelength can be stably emitted from the wavelength conversion unit 160. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser apparatus, an excimer laser apparatus, a light irradiation apparatus and an exposure apparatus, a light generation method, a light irradiation method, an exposure method, and a device manufacturing method, and more specifically, emits laser light having a predetermined wavelength in the ultraviolet region. Laser apparatus and excimer laser apparatus, light irradiation apparatus and exposure apparatus including the laser apparatus or excimer laser apparatus, light generation method for generating laser light of a predetermined wavelength in the ultraviolet region, light irradiation method using the method, and the light The present invention relates to an exposure method using a generation method and a device manufacturing method using the exposure method.

  Conventionally, a light irradiation apparatus has been used for inspection of the fine structure of an object, fine processing of the object, treatment for correcting vision, and the like. For example, in a lithography process for manufacturing a semiconductor element or the like, in order to transfer a pattern formed on a mask or a reticle onto a substrate such as a wafer or a glass plate coated with a resist or the like via a projection optical system, An exposure apparatus which is a kind of light irradiation apparatus is used. In addition, it is a kind of light irradiation device to treat myopia and astigmatism by performing ablation of the corneal surface (PRK: Photorefractive Keratectomy) or ablation of the cornea (LASIK: Laser Intrastromal keratomileusis) to correct vision. Some laser therapy devices are used.

  Many developments have been made on light sources that generate light of short wavelengths for such light irradiation devices. The direction of development of such short wavelength light sources is roughly divided into the following two types. One is the development of an excimer laser light source in which the laser oscillation wavelength itself is a short wavelength, and the other is the development of a short wavelength light source utilizing harmonic generation of an infrared or visible laser.

  Among these, along the former direction, a light source device using a KrF excimer laser (output wavelength 248 nm), an ArF excimer laser (output wavelength 193 nm) or the like has been put into practical use. However, since these excimer lasers are large in size and use fluorine gas which requires careful handling, there are disadvantages as a light source device such that the maintenance of the laser is complicated and expensive.

  Therefore, as a method of shortening the wavelength along the latter direction, long-wavelength light (infrared light, visible light) is converted into shorter-wavelength ultraviolet light using the nonlinear optical effect of the nonlinear optical crystal. The method attracts attention (see, for example, Patent Documents 1 and 2).

  However, for example, in the wavelength conversion unit having a final wavelength of 193 nm disclosed in Patent Documents 1 and 2, for synthesis of 200 nm band deep ultraviolet light and 1 μm band infrared light incident on the final wavelength conversion element At least a dichroic mirror was required. A general dichroic mirror is damaged by deep ultraviolet light. In addition, adjustment for superimposing 200 nm band deep ultraviolet light and 1 μm band infrared light incident on the final stage wavelength conversion element with a dichroic mirror is necessary, which is difficult.

International Publication No. 99/46835 Pamphlet JP 2004-086193 A

  From a first viewpoint, the present invention is a laser device that emits laser light having a predetermined wavelength, and first and second laser light sources that respectively generate first and second laser lights having different wavelengths; A laser beam having the predetermined wavelength is generated through a plurality of stages of wavelength conversion using the first and second laser beams, and a set of wavelength conversion elements arranged without passing through a multiplexing optical element is finalized. And a wavelength conversion unit included in the stage.

  Here, a set of wavelength conversion elements arranged without interposing a multiplexing optical element means that an optical element such as a dichroic mirror or a prism that synthesizes a plurality of laser beams coaxially has a wavelength different from that of the wavelength conversion element. It means a set of wavelength conversion elements that are not interposed between the conversion elements. Therefore, not only when there is no optical element between the wavelength conversion element and the wavelength conversion element, but also when there is an optical element that does not have a multiplexing function, such as a lens or a glass plate. Includes both.

  According to this, since the wavelength conversion unit has a set of wavelength conversion elements arranged without interposing the multiplexing optical element in its final stage, the positioning accuracy of the multiplexing optical element and the multiplexing by the irradiation of the laser light There is no need to consider deterioration of the optical element. Therefore, even if the power of the laser light generated by the first and second laser light sources is increased, it is possible to stably emit laser light having a predetermined wavelength from the wavelength conversion unit.

  From a second aspect, the present invention is a laser device that emits laser light having a predetermined wavelength, and a first laser light source that generates a first laser light having a wavelength of 1.0 to 1.2 μm; A second laser light source that generates a second laser beam having a wavelength of 1.5 to 2.1 μm; and a laser beam having the predetermined wavelength through a plurality of stages of wavelength conversion using the first and second laser beams. And a wavelength conversion unit including a first conversion unit for generating a third laser beam by performing sum-frequency mixing of the first laser beam and the second laser beam. Device.

  According to this, the sum frequency of the first laser beam having a wavelength of 1.0 to 1.2 μm and the second laser beam having a wavelength of 1.5 to 2.1 μm is obtained by the first conversion unit of the wavelength conversion unit. Mixing is performed, and third laser light having a wavelength different from both the harmonics of the first laser light and the second laser light is generated. Since further wavelength conversion is possible using this third laser light, in the case of wavelength conversion in which the harmonic of the first laser light or the harmonic of the second laser light is a laser light of a predetermined wavelength Therefore, it is possible to use a wavelength conversion element that could not be used and / or adopt a configuration of a wavelength conversion unit.

  From a third viewpoint, the present invention is a laser device that emits laser light of a predetermined wavelength, and first and second laser light sources that respectively generate first and second laser lights having different wavelengths; The laser beam having the predetermined wavelength is generated through a plurality of stages of wavelength conversion using the first and second laser beams, and the sum frequency mixing of the first laser beam and the second laser beam is performed. And a wavelength converter including a first converter that generates a third laser beam having a wavelength in the range of greater than 600 nm and less than 750 nm.

  According to this, the first conversion unit of the wavelength conversion unit performs the sum frequency mixing of the first laser beam and the second laser beam, and the third laser beam having a wavelength in the range of greater than 600 nm and less than 750 nm. Occurs. In this case, as an example, laser light having a wavelength of 1.0 to 1.2 μm and laser light having a wavelength of 1.5 to 2.1 μm can be used as the first and second laser lights, respectively. Therefore, use of a wavelength conversion element that could not be used in the case of wavelength conversion in which the harmonic of the first laser light or the harmonic of the second laser light is converted into laser light having a predetermined wavelength, and / or a wavelength conversion unit It is possible to adopt the configuration.

  According to a fourth aspect of the present invention, there is provided a light irradiation apparatus for irradiating an object with light, and any one of the first to third laser apparatuses of the present invention; from the laser apparatus toward the object And an optical system through which the emitted laser light passes.

  According to this, since any one of the first to third laser devices of the present invention is provided, it is possible to stably irradiate the object with laser light having a predetermined wavelength via the optical system. Become.

  According to a fifth aspect of the present invention, there is provided an excimer laser device that emits excimer laser light, the main oscillator including any one of the first to third laser devices of the present invention; An excimer laser device comprising: a gas laser chamber that uses a laser beam as a seed beam and amplifies the seed beam.

  According to this, since the main oscillator includes any one of the first to third laser devices of the present invention, it is possible to emit the excimer laser light stably.

  According to a sixth aspect of the present invention, there is provided a light irradiation apparatus for irradiating light on an object, the excimer laser apparatus of the present invention; and laser light emitted from the excimer laser apparatus toward the object. A second light irradiation device comprising: an optical system that passes therethrough.

  According to this, since the excimer laser device of the present invention is provided, it is possible to stably irradiate an object with excimer laser light having a predetermined wavelength via the optical system.

  According to a seventh aspect of the present invention, there is provided an exposure apparatus for exposing an object to form a pattern on the object, wherein the exposure apparatus comprises any one of the first to third laser apparatuses of the present invention; And an optical system through which a laser beam emitted toward the object passes.

  According to this, it is possible to stably form a pattern on an object by stably irradiating the object with laser light having a predetermined wavelength emitted from the laser device via the optical system.

  According to an eighth aspect of the present invention, there is provided a light generation method for generating laser light having a predetermined wavelength, wherein first and second laser lights having different wavelengths are respectively generated from first and second laser light sources. And a plurality of stages of wavelength conversion using the first and second laser beams by a wavelength converter having a set of wavelength converters arranged at the final stage without any intervening optical elements. And a first light generation method.

  According to this, since a wavelength conversion unit having a set of wavelength conversion elements arranged without interposing the multiplexing optical element in its final stage is used, the positioning accuracy of the multiplexing optical element and the irradiation of laser light are used. There is no need to consider deterioration of the multiplexing optical element. Therefore, even if the power of the laser light generated by the first and second laser light sources is increased, the laser light having a predetermined wavelength is stably emitted from the wavelength conversion unit.

  According to a ninth aspect, the present invention is a light generation method for generating laser light having a predetermined wavelength, wherein the first laser light has a wavelength of 1.0 to 1.2 μm from the first and second laser light sources. A step of generating a second laser beam having a wavelength of 1.5 to 2.1 μm; and a sum frequency mixing of the first laser beam and the second laser beam to generate a third laser beam. A step of performing wavelength conversion in a plurality of stages including wavelength conversion to be generated.

  According to this, the sum frequency mixing of the 1st laser beam with a wavelength of 1.0-1.2 micrometers and the 2nd laser beam with a wavelength of 1.5-2.1 micrometers is performed, and the 1st laser beam A third laser beam having a wavelength different from both of the second harmonic and the second laser beam is generated. Since further wavelength conversion is possible using this third laser light, in the case of wavelength conversion in which the harmonic of the first laser light or the harmonic of the second laser light is a laser light of a predetermined wavelength Therefore, it is possible to use a wavelength conversion element that could not be used and / or adopt a configuration of a wavelength conversion unit.

  According to a tenth aspect of the present invention, there is provided a light generation method for generating laser light having a predetermined wavelength, wherein first and second laser lights having different wavelengths are respectively generated from first and second laser light sources. A plurality of stages of wavelengths including a first conversion that performs sum frequency mixing of the first laser beam and the second laser beam to generate a third laser beam having a wavelength in the range of greater than 600 nm and less than 750 nm A third light generation method including: a step of performing conversion.

  According to this, the sum frequency mixing of the first laser beam and the second laser beam is performed, and a third laser beam having a wavelength in a range larger than 600 nm and smaller than 750 nm is generated. In this case, as an example, laser light having a wavelength of 1.0 to 1.2 μm and laser light having a wavelength of 1.5 to 2.1 μm can be used as the first and second laser lights, respectively. Therefore, use of a wavelength conversion element that could not be used in the case of wavelength conversion in which the harmonic of the first laser light or the harmonic of the second laser light is converted into laser light having a predetermined wavelength, and / or a wavelength conversion unit It is possible to adopt the configuration.

  According to an eleventh aspect of the present invention, there is provided an excimer laser light generation method for generating laser light having a predetermined wavelength, wherein the laser light having the predetermined wavelength is generated by any one of the first to third light generation methods of the present invention. An excimer laser light generation method including: a second step of causing the laser light to enter the gas laser chamber as a seed light and amplifying the seed light in the gas laser chamber.

  According to this, the laser light generated by any one of the first to third light generation methods of the present invention enters the gas laser chamber as seed light, and the seed light is amplified in the gas laser chamber. As a result, the excimer laser light amplified from the gas laser chamber can be stably emitted.

  According to a twelfth aspect of the present invention, there is provided a light irradiation method for irradiating an object with light, the step of generating laser light by any one of the first to third light generation methods of the present invention; And a step of emitting laser light toward the object through an optical system.

  According to this, laser light of a predetermined wavelength is stably irradiated onto the object via the optical system by any one of the first to third light generation methods of the present invention.

  According to a thirteenth aspect of the present invention, there is provided an exposure method for exposing an object to form a pattern on the object, wherein laser light is generated by any one of the first to third light generation methods of the present invention. And a step of emitting the laser beam toward the object through an optical system.

  According to this, by any one of the first to third light generation methods of the present invention, laser light having a predetermined wavelength is stably irradiated onto the object via the optical system, and the pattern is stabilized on the object. Formed.

  In the lithography process, by forming a pattern on the object using the exposure method of the present invention, the pattern can be stably formed on the object, and the productivity of the device can be improved. Therefore, it can be said that this invention is a device manufacturing method using the exposure method of this invention from another viewpoint.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of an exposure apparatus 10 according to an embodiment to which the light generation method and the light irradiation method of the present invention are applied. The exposure apparatus 10 is a step-and-scan scanning exposure apparatus (so-called scanner).

  The exposure apparatus 10 includes a laser device 16, an illumination optical system unit 12, and a reticle (mask) that is illuminated by exposure illumination light (hereinafter referred to as “illumination light” or “exposure light” as appropriate) IL from the illumination optical system unit 12. ) Reticle stage RST for holding R, projection optical system PL for projecting exposure light IL via reticle R onto wafer (object) W, wafer stage WST for holding wafer W, and main controller 50 for controlling them Etc.

  The laser device 16 is, for example, a device that emits ultraviolet pulse light having a wavelength of 193.4 nm. As shown in FIG. 2, the laser device 16 includes a clock generator 161, four delay circuits (162a, 162b, 162c, 162d), four pulse generators (163a, 163b, 163c, 163d), It includes four laser light sources (164a, 164b, 164c, 164d), four optical amplifiers (165a, 165b, 165c, 165d), a wavelength converter 160, and the like.

  The clock generator 161 is controlled by the main controller 50 and generates a clock signal. The clock signal generated by the clock generator 161 is supplied to each of the delay circuits 162a, 162b, 162c, and 162d.

  Each of the delay circuits 162a, 162b, 162c, and 162d performs wavelength conversion in each wavelength conversion element (nonlinear optical crystal) described later that performs sum frequency mixing of laser beams that have passed through different paths, particularly wavelength conversion elements 167d and 167e. Are delayed as much as possible, that is, so that a plurality of laser beams having different wavelengths are overlapped as much as possible inside the wavelength conversion elements. The delay time of each of the delay circuits 162a, 162b, 162c, 162d takes into consideration the difference in the speed of each laser beam in each wavelength conversion element, the difference in the optical path length from each laser light source to each wavelength conversion element, etc. It is predetermined. Therefore, instead of the delay circuits 162a, 162b, 162c, and 162d, a delay device that optically delays each laser beam may be used. Further, the delay time of each of the delay circuits 162a, 162b, 162c, 162d is set based on the delay time of one specific delay circuit, so that the specific one delay circuit is set. Is not necessarily provided. The same applies when a delay device is used.

  The pulse generators 163a, 163b, 163c, and 163d generate pulse signals based on the clock signals that have passed through the delay circuits 162a, 162b, 162c, and 162d, respectively.

  The laser light source 164a includes a single wavelength oscillation laser having an oscillation wavelength in the range of 1020 nm to 1150 nm, for example, 1105 nm, for example, a DFB semiconductor laser, and pulses laser light having a wavelength of 1105 nm according to a pulse signal from the pulse generator 163a. Emits light.

  The laser light source 164b includes a single wavelength oscillation laser having an oscillation wavelength in the range of 1020 nm to 1150 nm, for example, 1105 nm, for example, a DFB semiconductor laser, and pulses laser light having a wavelength of 1105 nm in accordance with a pulse signal from the pulse generator 163b. Emits light.

  The laser light source 164c includes a single wavelength oscillation laser having an oscillation wavelength in a range of 1520 nm to 1620 nm, for example, 1547 nm, for example, a DFB semiconductor laser, and pulses laser light having a wavelength of 1547 nm in accordance with a pulse signal from the pulse generator 163c. Emits light.

  The laser light source 164d includes a single wavelength oscillation laser having an oscillation wavelength in the range of 1020 nm to 1150 nm, for example, 1105 nm, for example, a DFB semiconductor laser, and pulses laser light having a wavelength of 1105 nm according to a pulse signal from the pulse generator 163d. Emits light.

  As single wavelength oscillation lasers constituting the laser light sources 164a, 164b, and 164d, for example, ytterbium-doped fiber lasers can be used. As the single wavelength oscillation laser constituting the laser light source 164c, for example, an erbium-doped fiber laser can be used.

  In the present embodiment, the main control device 50 individually detects (monitors) the light emission power of the laser light in the laser light sources 164a, 164b, 164c, and 164d, and the drive signal of each single wavelength oscillation laser according to the detection result. Are controlled individually.

  The optical amplifier 165a amplifies laser light having a wavelength of 1105 nm from the laser light source 164a. As the optical amplifier 165a, for example, an ytterbium-doped fiber optical amplifier (hereinafter abbreviated as “YDFA”) having a large mode diameter is used. For this reason, it is possible to increase the peak power of laser light having a wavelength of 1105 nm that enters the wavelength conversion element 167a described later from the optical amplifier 165a via the condenser lens 166a.

  The optical amplifier 165b amplifies the laser beam having a wavelength of 1105 nm from the laser light source 164b. For example, YDFA having a large mode diameter is used as the optical amplifier 165b. For this reason, it is possible to increase the peak power of laser light having a wavelength of 1105 nm that enters the dichroic mirror 168a described later from the optical amplifier 165b through the condenser lens 166c.

  The optical amplifier 165c amplifies laser light having a wavelength of 1547 nm from the laser light source 164c. As the optical amplifier 165c, for example, an erbium-doped fiber optical amplifier (hereinafter abbreviated as “EDFA”) having a large mode diameter is used. Therefore, it is possible to increase the peak power of laser light having a wavelength of 1547 nm that enters the dichroic mirror 168a described later from the optical amplifier 165c through the condenser lens 166e.

  The optical amplifier 165d amplifies the laser beam having a wavelength of 1105 nm from the laser light source 164d. For example, YDFA having a large mode diameter is used as the optical amplifier 165d. For this reason, it is possible to increase the peak power of laser light having a wavelength of 1105 nm that enters the dichroic mirror 168b described later from the optical amplifier 165d through the condenser lens 166f.

  In FIG. 2, it is assumed that only one optical amplifier 165a to 165d is provided, but it is needless to say that at least one of them may be provided in a plurality of stages. In other words, in at least one of the optical amplifiers 165a to 165d, the fiber laser amplifier may be a multistage configuration, and incident laser light may be amplified a plurality of times. Further, in at least one of the optical amplifiers 165a to 165d, the incident laser light may be branched into a plurality of parts, and the plurality of branched lights may be amplified by a single-stage or multi-stage fiber optical amplifier. In this case, the plurality of amplified branched lights may be coaxially synthesized and output. Further, instead of separately detecting the light emission power of the laser light in each laser light source and individually controlling the drive signal of the laser light source according to the detection result, or together with this, the optical amplifiers 165a, 165b, 165c, 165d It is also possible to detect (monitor) the power of each laser beam on the optical path provided respectively, and to control each optical amplifier according to the detection result.

  As shown in an enlarged view in FIG. 3, the wavelength converter 160 includes a plurality of wavelength conversion elements (nonlinear optical crystals) 167a to 167e, and a plurality of stages using the pulsed laser light from the optical amplifiers 165a to 165d as incident light. To generate pulsed ultraviolet light having a wavelength of 193.4 nm, which is substantially the same wavelength as the ArF excimer laser light.

  Here, the wavelength converter 160 will be described with reference to FIG. In FIG. 3, laser beams L1, L2, and L4 having a wavelength of 1105 nm emitted from the optical amplifiers 165a, 165b, and 165d are defined as the first fundamental wave (first fundamental light), and the wavelength of 1547 nm from the optical amplifier 165c is used. Shows a configuration example in which a laser beam L3 is converted into a second fundamental wave (second fundamental light), wavelength conversion is performed using a nonlinear optical crystal, and ultraviolet light of 193.4 nm having substantially the same wavelength as an ArF excimer laser is generated. Has been. Here, the fundamental wave (fundamental light) is a laser beam incident on the wavelength conversion unit 160 from the outside, and is the basis of wavelength conversion that has never been used for wavelength conversion inside the wavelength conversion unit 160. This means laser light.

Laser light L1 (first fundamental wave) having a wavelength of 1105 nm (frequency ω ₁ ) emitted from the optical amplifier 165a is incident on the wavelength conversion element 167a. When the first fundamental wave L1 passes through the wavelength conversion element 167a, the second harmonic generation generates twice the frequency ω ₁ of the first fundamental wave, that is, the frequency 2ω ₁ (the wavelength is 552. 5 nm) is generated.

As this wavelength conversion element 167a, a non-linear optical element made of LiB ₃ O ₅ crystal (LBO crystal) is used, and a method by adjusting the temperature of the LBO crystal for phase matching for wavelength conversion of the fundamental wave to a double wave, that is, NCPM (Non-Critical Phase Matching) is used. NCPM does not cause an angular shift (Walk-off) between the fundamental wave and the second harmonic in the nonlinear optical crystal, so it can be converted to a double wave with high efficiency and has occurred. The second harmonic has the advantage that it does not undergo beam deformation due to walk-off. In this case, the temperature of the wavelength conversion element 167a is maintained at 103 ° C. so that NCPM is satisfied. The nonlinear coefficient diff of the wavelength conversion element 167a is 0.86 pm / V.

  In this case, since the laser light L1 having a wavelength of 1105 nm having a high peak power is incident on the wavelength conversion element 167a, the wavelength conversion element 167a can increase the conversion efficiency. Therefore, even if the beam diameter of the laser light incident on the wavelength conversion element 167a is relatively large, it is possible to generate laser light having a wavelength of 552.5 nm with a desired conversion efficiency. Further, even if the length of the LBO crystal is shortened, it is possible to generate laser light having a wavelength of 552.5 nm with a desired conversion efficiency.

  Thus, since the wavelength conversion element 167a uses NCPM and performs wavelength conversion with high conversion efficiency, it is possible to suppress the elliptical shape of the beam shape of the laser light emitted from the wavelength conversion element 167a. it can. That is, laser light having excellent beam quality is emitted from the wavelength conversion element 167a.

The first fundamental wave transmitted without being wavelength-converted by the wavelength conversion element 167a and the second harmonic wave generated by the wavelength conversion are delayed by half wavelength and one wavelength respectively by a wavelength plate (not shown) via the condenser lens 166b. And the polarization direction of only the fundamental wave is rotated by 90 degrees and is incident on the wavelength conversion element 167b. As the wavelength conversion element 167b, a non-linear optical element made of β-BaB ₂ O ₄ (BBO) crystal is used. The wavelength conversion element 167b performs sum frequency mixing of the second harmonic wave generated by the wavelength conversion element 167a and the first fundamental wave that has passed through the wavelength conversion element 167a without wavelength conversion, and has a frequency of 3ω ₁ (wavelength is 1105 nm). 1/3 of 368.3 nm) is generated. The nonlinear coefficient diff of the wavelength conversion element 167b is 2.0 pm / V, and the walk-off angle is 70 mrad. Thus, the third harmonic generated from the wavelength conversion element 167b has an elliptical cross section because of the walk-off, and as such, the light collecting property is poor and cannot be used for the next wavelength conversion. For this reason, in the present embodiment, the cylindrical lens 169a and the cylindrical lens 169b are disposed at the subsequent stage of the wavelength conversion element 167, and the laser light from the wavelength conversion element 167b has a circular cross-sectional shape by the cylindrical lenses 169a and 169b. After being shaped in such a manner, it is incident on the dichroic mirror 168c.

On the other hand, a laser beam L2 (first fundamental wave) having a wavelength of 1105 nm (frequency ω ₁ ) emitted from the optical amplifier 165b and a laser beam L3 (second fundamental wave) having a wavelength of 1547 nm (frequency ω ₂ ) emitted from the optical amplifier 165c. Are combined coaxially by the dichroic mirror 168a. Then, the combined light (the combined light) of the laser light L2 and the laser light L3 combined coaxially enters the wavelength conversion element 167c at the subsequent stage.

As the wavelength conversion element 167c, a non-linear optical element made of an LBO crystal is used, and the wavelength conversion element 167c uses NCPM at a temperature (for example, 12 ° C.) different from that of the wavelength conversion element (LBO crystal) 167a. In this wavelength conversion element 167c, the frequency (ω ₁ + ω ₂ ) (laser light L1, L1) is obtained by sum frequency mixing of the laser light L2 having a wavelength of 1105 nm (frequency ω ₁ ) and the laser light L3 having a wavelength of 1547 nm (frequency ω ₂ ). A laser beam having a wavelength of λ _L1 and λ _{L2 and} a wavelength of λ _L1 λ _L2 / λ _L1 + λ _L2 ≈645 nm) is generated. The nonlinear coefficient diff of the wavelength conversion element 167c is 0.86 pm / V.

  Since the laser light L2 having a high peak power of 1105 nm and the laser light L3 having a high peak power of 1547 nm are incident on the wavelength conversion element 167c, the wavelength conversion element 167c can increase the conversion efficiency. Therefore, it is possible to generate a laser beam having a wavelength of 645 nm with a desired conversion efficiency even if the beam diameter of the laser beam incident on the wavelength conversion element 167c is relatively large. In addition, even if the length of the LBO crystal is shortened, it is possible to generate laser light having a wavelength of 645 nm with a desired conversion efficiency.

  In addition, since NCPM is used in the wavelength conversion element 167c, walk-off does not occur, highly efficient wavelength conversion is possible, and deformation of the beam shape due to walk-off does not occur. Therefore, laser light having excellent beam quality is emitted from the wavelength conversion element 167c.

  The laser beam having a wavelength of 645 nm emitted from the wavelength conversion element 167c is incident on the dichroic mirror 168b via the condenser lens 166d, and the dichroic mirror 168b emits a laser beam L4 having a wavelength of 1105 nm emitted from the optical amplifier 165d. 1 fundamental wave) and is coaxially synthesized and proceeds toward the dichroic mirror 168c. The dichroic mirror 168b reflects laser light having a wavelength of 645 nm and transmits laser light having a wavelength of 1105 nm.

  The coaxially synthesized laser beam having a wavelength of 645 nm and the laser beam L4 having a wavelength of 1105 nm are synthesized coaxially with a laser beam having a wavelength of 368.3 nm, which is beam-shaped by the cylindrical lenses 169a and 169b by the dichroic mirror 168c. And enters the wavelength conversion element 167d.

As the wavelength conversion element 167d, for example, a nonlinear optical element made of a CsLiB ₆ O ₁₀ crystal (CLBO crystal) is used. The nonlinear coefficient diff of the wavelength conversion element 167d is 0.93 pm / V, and the walk-off angle is 15 mrad. The wavelength conversion element 167d is a sum frequency of the laser light having a wavelength of 368.3 nm generated by the wavelength conversion element 167b and the laser light having a wavelength of 645 nm generated by the wavelength conversion element 167c, which is included in the laser light via the dichroic mirror 168c. Mixing is performed to generate laser light having a wavelength of 234 nm (frequency is 4ω ₁ + ω ₂ ).

  In this case, high-quality laser light is incident on the wavelength conversion element 167d, and the wavelength conversion element 167d is used at an angle with a relatively large nonlinear coefficient diff and a small walk-off angle. Further, as described above, in this embodiment, a fiber optical amplifier having a large mode diameter is used as each optical amplifier, and a laser beam with a high peak power can be used as each fundamental wave. It can be shortened and / or allowed to increase the incident beam diameter. For this reason, the wavelength conversion element 167d can perform wavelength conversion with high conversion efficiency, and the laser light generated by the wavelength conversion is laser light with small distortion from the Gaussian beam. That is, the laser beam having a wavelength of 234 nm (deep ultraviolet region) from the wavelength conversion element 167d has excellent beam quality. Therefore, the laser beam having a wavelength of 234 nm (deep ultraviolet region) from the wavelength conversion element 167d is used for wavelength conversion in the wavelength conversion element in the subsequent stage (in this embodiment, the wavelength conversion element 167e) without any correction. it can. For this reason, in this embodiment, no optical element is provided between the wavelength conversion element 167d and the wavelength conversion element 167e. On the optical path of the laser light from the wavelength conversion element 167d, not only a cylindrical lens but also deep ultraviolet light having a wavelength of 200 nm (234 nm as an example) and infrared light having a wavelength of 1 μm (1105 nm as an example) are combined. The wavelength conversion element 167e can be arranged without interposing a dichroic mirror for wave generation.

  For example, a glass plate may be disposed on the optical path of the laser light between the wavelength conversion element 167d and the wavelength conversion element 167e. Further, at least one of the wavelength conversion element 167d and the wavelength conversion element 167e may be formed into a so-called cell and covered with protective glass.

The laser beam having a wavelength of 234 nm generated by the wavelength conversion element 167d is combined with the laser light L4 having a wavelength of 1105 nm (1.1 μm band) from the fiber optical amplifier 165d that has passed through the wavelength conversion element 167d, and the wavelength conversion element 167e disposed immediately thereafter. Is incident on. As the wavelength conversion element 167e, for example, a nonlinear optical element made of a CLBO crystal is used. The wavelength conversion element 167e has a nonlinear coefficient diff of 1.1 pm / V and a walk-off angle of 3 mrad. The wavelength conversion element 167e generates laser light having a wavelength of 193.4 nm (frequency is 5ω ₁ + ω ₂ ) by the sum frequency mixing of the laser light having a wavelength of 234 nm and the laser light L4 generated by the wavelength conversion element 167d.

  In this case, a laser beam having a high beam quality is incident on the wavelength conversion element 167e, and a CLBO crystal is used as the wavelength conversion element 167e at an angle at which the walk-off angle is substantially zero. Therefore, the wavelength conversion element 167e The laser beam having a wavelength of 193.4 nm from the laser beam is extremely excellent in beam quality. This laser beam having a wavelength of 193.4 nm is emitted from the laser device 16 and enters the illumination optical system 12.

  Returning to FIG. 1, the illumination optical system unit 12 includes, for example, an illumination system housing connected to the laser device 16 via a light transmission optical system and an illumination optical system inside the illumination system housing. The illumination optical system includes, for example, an illuminance uniformizing optical system including an optical integrator, a reticle blind, and the like as disclosed in Japanese Patent Laid-Open No. 2001-313250 (corresponding to US Patent Application Publication No. 2003/0025890). All of which are not shown). Here, as the optical integrator, a fly-eye lens, an internal reflection type integrator (rod integrator or the like), a diffractive optical element, or the like is used. The exposure light IL emitted from the illumination optical system unit 12 has its optical path bent vertically downward by the mirror M, then passes through the condenser lens 32, and on the reticle R held on the reticle stage RST in the X-axis direction (FIG. 1 is illuminated with a uniform illuminance distribution. The illumination optical system described above may also include the mirror M and the condenser lens 32.

  On reticle stage RST, reticle R is placed and held by suction via a vacuum chuck or the like (not shown). Reticle stage RST can be finely driven in a horizontal plane (XY plane) and is scanned within a predetermined stroke range in the scanning direction (here, the Y-axis direction which is the horizontal direction in FIG. 1) by reticle stage driving system 49. Is done. The position and amount of rotation of reticle stage RST during scanning are measured by laser interferometer 54R via movable mirror 52R (or a reflection surface formed on its side surface) fixed on reticle stage RST, and this laser interference. The measured value of the total 54R is supplied to the main controller 50.

  The projection optical system PL is a double-sided telecentric reduction system, for example, and includes a plurality of lens elements arranged along an optical axis AX parallel to the Z-axis direction. Further, as the projection optical system PL, one having a projection magnification β of, for example, 1/4, 1/5, 1/6, or the like is used. For this reason, when the illumination area 42R on the reticle R is illuminated by the exposure light IL, the pattern formed on the reticle R is reduced and projected at the projection magnification β by the projection optical system PL, and a reduced image (partial image) of the pattern is obtained. Is generated (formed) in an exposure region 42W conjugate to the illumination region 42R on the wafer W having a resist (photosensitive agent) coated on the surface thereof. The projection optical system may be not only a reduction system but also an equal magnification system and an enlargement system, and may be any of a reflection system and a catadioptric system as well as a refraction system, and the projection image is an inverted image or an erect image. Either is fine.

  Wafer stage WST includes, for example, an XY stage 14 driven in the XY plane by a wafer stage drive system 56 including a linear motor and the like, and a Z tilt stage 58 mounted on the XY stage 14. A wafer W is held on the Z tilt stage 58 by vacuum suction or the like via a wafer holder (not shown). The Z tilt stage 58 adjusts the position (focus position) of the wafer W in the Z-axis direction by using, for example, three actuators (piezo elements or voice coil motors) and the wafer with respect to the XY plane (image plane of the projection optical system PL). It has a function of adjusting the inclination angle of W. Further, position information and rotation information in the XY plane of the Z tilt stage 58 (rotation around the X axis (θx rotation), rotation around the Y axis (θy rotation), and rotation around the Z axis (θz rotation)) are: Measurement is performed by a laser interferometer 54W via a movable mirror 52W fixed on the Z tilt stage 58, and a measurement value of the laser interferometer 54W is supplied to the main controller 50. Instead of the XY stage 14 and the Z tilt stage 58, a single 6-degree-of-freedom stage on which a wafer is placed may be used. Further, instead of the movable mirror 52W, the end surface of the Z tilt stage 58 may be mirror-finished to form a reflective surface (corresponding to the reflective surface of the movable mirror 52W).

  The main controller 50 includes a so-called microcomputer (or workstation) composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. In addition to performing the various controls described above, for example, synchronous scanning of the reticle R and the wafer W, stepping of the wafer W, exposure timing, and the like are controlled so that the exposure operation is performed accurately. In addition, the main controller 50 performs overall control of the entire apparatus, in addition to controlling the exposure amount during scanning exposure.

Specifically, the main controller 50 synchronizes with the reticle R being scanned at a speed V _R = V in the + Y direction (or −Y direction) via the reticle stage RST at the time of scanning exposure, for example. Laser so that the wafer W is scanned through the stage WST in the −Y direction (or + Y direction) at the speed V _W = β · V (β is the projection magnification from the reticle R to the wafer W) with respect to the exposure region 42W. Based on the measurement values of interferometers 54R and 54W, the positions and speeds of reticle stage RST and wafer stage WST are controlled via reticle stage drive system 49 and wafer stage drive system 56, respectively. At the time of stepping, main controller 50 controls the position of wafer stage WST via wafer stage drive system 56 based on the measurement value of laser interferometer 54W.

  In the exposure apparatus 10, when manufacturing a device, the reticle alignment, the baseline measurement of an alignment system (not shown), and the wafer alignment (for example, in Japanese Patent Application Laid-Open No. 61-44429) are performed in the same procedure as a normal scanning stepper (scanner). After the disclosed enhanced global alignment (EGA) or the like is performed, the above-described scanning exposure operation in which the reticle stage RST and the wafer stage WST are moved synchronously, and the wafer stage WST after the exposure of the shot area is completed, A step-and-scan exposure operation that alternately repeats an inter-shot moving (stepping) operation for moving to an acceleration start position for exposure of the next shot region is performed, and a plurality of shot regions on the wafer W are subjected to reticle R. Each pattern is transferred.

  As described above, according to the laser device 16 according to the present embodiment, the wavelength conversion unit 160 is disposed on the optical path of the laser light so as to be adjacent to each other without using a multiplexing optical element such as a dichroic mirror. Since the wavelength conversion elements 167d and 167e are provided at the final stage, there is no need to consider deterioration of the multiplexing optical element due to laser light irradiation. Accordingly, since the power of the laser light generated by the laser light sources 164a to 164d can be increased, the laser light having a wavelength of 193.4 nm can be stably emitted from the wavelength conversion unit 160. Further, since there is no multiplexing optical element between the wavelength conversion element 167d and the wavelength conversion element 167e, it is not necessary to consider the position adjustment of the multiplexing optical element.

  Further, according to the laser device 16, the dichroic mirror 168a of the wavelength converter 160 coaxially couples the laser light L2 having a wavelength of 1.1 μm, for example, 1105 nm, and the laser light L3 having a wavelength of 1.5 μm, for example, 1547 nm. Are combined (combined) by the wavelength conversion element 167c, and the sum frequency mixing of the laser light L2 and the laser light L3 is performed by the wavelength conversion element 167c, and the harmonics of the laser light having the wavelength of 1105 nm (1.1 μm band) and the wavelength 1547 (1 A laser beam having a wavelength of 645 nm that is different from any of the harmonics of the laser beam in the .5 μm band is generated. For this reason, since further wavelength conversion becomes possible using this laser beam with a wavelength of 645 nm, the harmonics of the laser beam with a wavelength of 1105 nm (1.1 μm band) or the laser beam with a wavelength of 1547 (1.5 μm band) A wavelength conversion element that could not be used in the case of wavelength conversion using harmonics as laser light of the target wavelength, specifically, a CLBO crystal at an angle where the nonlinear coefficient diff is 0.93 pm / V and the walk-off angle is 15 mrad In addition, it is possible to use a CLBO crystal at an angle at which the nonlinear coefficient def is 1.1 pm / V and the walk-off angle is 3 mrad as the wavelength conversion elements 167d and 167e, and the above-described wavelength conversion unit 160 that has not been conventionally used. The configuration can be adopted.

  As a result of employing the wavelength conversion elements 167d and 167e, as described above, the wavelength conversion element 167d can generate laser light having a wavelength of 234 nm with excellent beam quality, and the wavelength conversion element 167e has excellent beam quality. In addition, laser light having a wavelength of 193.4 nm can be generated.

  Further, according to the laser device 16 of the present embodiment, the laser beams L1 to L4 are amplified to a high peak power laser beam by a fiber optical amplifier having a large mode diameter, and enter each wavelength conversion element. Therefore, it is possible to allow the crystal length of each wavelength conversion element to be shortened and / or to increase the incident beam diameter while maintaining a relatively high conversion efficiency. Further, since a fiber optical amplifier having a large mode diameter is used, the temporal width of the pulse can be increased while maintaining a relatively high peak power. The spectrum of the 4 nm laser beam can be narrowed.

  According to the exposure apparatus 10 of the present embodiment, a laser beam (illumination light IL) having a wavelength of 193.4 nm generated by the laser apparatus 16 in the above-described scanning exposure is transmitted through the illumination optical system unit 12 (illumination optical system). Illumination light IL irradiated onto R and transmitted through reticle R is projected onto wafer W via projection optical system PL. In this case, the laser light (illumination light IL) having a wavelength of 193.4 nm generated by the laser device 16 has excellent beam quality, and the repetition frequency is equal to or higher than that of the conventional excimer laser. The pattern of the reticle R can be accurately formed in each shot area.

In the above embodiment, the case where the wavelength conversion element 167c performs the sum frequency mixing of the laser light L2 and the laser light L3 to generate the laser light having a wavelength of 645 nm has been described, but the present invention is not limited thereto. Is not to be done. Assuming that the amplifiable wavelength range of YDFA is 1020 nm to 1150 nm and the amplifiable wavelength range of EDFA is 1520 nm to 1620 nm, the wavelength conversion element 167c is a sum frequency mixing of the laser light L2 and the laser light L3. When the wavelength of the laser light is lambda ₁ generated by, lambda ₁ ranges from amplifiable wavelength range of YDFA and EDFA, 610nm <λ ₁ <may be satisfied 660 nm. In such a case, for example, a laser beam having a wavelength of 1.1 μm and a laser beam having a wavelength of 1.5 μm can be used as the laser beams L2 and L3, respectively. And / or the configuration of the wavelength converter can be adopted.

In this case, if the wavelength of the light generated by the wavelength conversion element 167b is λ ₂ , the wavelength of the light generated by the wavelength conversion element 167d is λ ₃ , and the final wavelength is 193.4 nm, the range of phase matching and the YDFA From the amplifiable wavelength range, the range of λ ₃ is 232 nm <λ ₃ <235 nm. Therefore, the range of λ ₂ is 357 nm <λ ₂ <383 nm from the range of λ _{3 and} the range of λ ₁ .

  In the wavelength converter 160 having the configuration shown in FIG. 3, fiber light to which Tm (thulium) or Ho (holmium) is added as the second fundamental wave instead of the light output from the EDFA. Light output from the amplifier may be used. When the thulium (or holmium) doped fiber optical amplifier whose output wavelength is 2 μm band is applied instead of the EDFA whose output wavelength is 1.5 μm band as described above, the wavelength of light output from YDFA Is about 1062 nm. Since the Yb fluorescence cross-sectional area is larger than the wavelength 1105 nm at the wavelength 1062 nm, it is advantageous for amplification of high peak power. However, even in this case, the wavelength of the laser beam used as L4 needs to be around 1105 nm from the phase matching condition in the wavelength conversion element 167e.

Further, the wavelength conversion unit 160 described above can obtain light having a wavelength (193.4 nm) that is substantially the same as the oscillation wavelength of the ArF excimer laser. In the present embodiment, the wavelength conversion unit 160 has the configuration of the wavelength conversion unit 160. If changed, for example, it becomes possible to obtain a wavelength substantially the same as the oscillation wavelength of KrF excimer laser (near 248 nm) or the oscillation wavelength of F ₂ laser (near 157 nm). In the laser device of the above embodiment, the oscillation wavelength may be different from any of the oscillation wavelengths of KrF excimer laser light, ArF excimer laser light, and F ₂ laser light, and in the far ultraviolet region or the vacuum ultraviolet region. Although not limited, it is particularly effective as a laser device that generates laser light having a wavelength of 200 nm or less.

  In addition, the nonlinear optical crystal which comprises each wavelength conversion element demonstrated by the said embodiment is an example, Comprising: This invention is not limited to this. For example, the wavelength conversion element 167c is not limited to a nonlinear optical element made of an LBO crystal, and for example, a nonlinear optical element using PPLN (Periodically Poled Lithium Niobate) or PPSLT (Periodically Poled Stoichiometric Lithium Tantalate) can also be used.

  In the laser device of the above-described embodiment, the case where laser light is emitted from each single wavelength oscillation laser has been described. However, the present invention is not limited to this, and laser light is continuously emitted from each single wavelength oscillation laser. The laser beam may be converted into pulsed light using, for example, an electro-optic modulator (two-electrode modulator or the like). Further, the pulse width of the laser light pulsed from each single wavelength oscillation laser may be narrowed by the electro-optic modulator or the like.

  In the laser apparatus of the above embodiment, the case where all the optical amplifiers are all fiber optical amplifiers has been described, but the present invention is not limited to this. Each optical amplifier may include, for example, a glass body to which a rare earth element is added at a high concentration instead of or in combination with a fiber optical amplifier.

  In the laser device of the above embodiment, the case where three single-wavelength oscillation lasers with an oscillation wavelength of 1020 nm to 1150 nm are provided has been described. However, one single-wavelength oscillation laser with an oscillation wavelength of 1020 nm to 1150 nm is provided, The laser beam from the laser may be divided into three.

  In the laser device of the above-described embodiment, an ytterbium-doped fiber laser is used as a single wavelength oscillation laser having an oscillation wavelength of 1020 nm to 1150 nm, that is, a laser light source that generates the first fundamental wave (L1, L2, L4). An erbium-doped fiber laser is used as a single wavelength oscillation laser having an oscillation wavelength of 1520 nm to 1620 nm, that is, a laser light source for generating the second fundamental wave (L3). However, the laser light source is not limited to these. Other solid-state laser light sources or harmonic generators may be used.

  In the laser apparatus of the above embodiment, the three laser beams (first fundamental waves) L1, L2, and L4 have the same wavelength. However, the present invention is not limited to this, and part of the three laser beams. Alternatively, the wavelengths may be varied in all. For example, when a thulium (or holmium) doped fiber optical amplifier with an output wavelength of 2 μm is used instead of the EDFA as described above, the laser beams L1 and L2 have a wavelength of about 1062 nm, and the laser beam L4 has a wavelength of About 1105 nm.

In the laser device of the above embodiment, assuming that the final wavelength is 193 nm, the first fundamental wave has a wavelength of 1.1 μm, and the second fundamental wave has a wavelength of 1.5 μm. However, assuming that the final wavelength is 190 nm to 200 nm, the wavelength of the first fundamental wave (laser beams L1, L2, and L4) is 1.0 μm to 1.2 μm, and the wavelength of the second fundamental wave (laser beam L3). May be 1.5 μm to 2.1 μm. In this case, an ytterbium-doped fiber laser can be used as the laser light source for generating the first fundamental wave, as in the above embodiment, and erbium-doped as the laser light source for generating the second fundamental wave. A fiber laser or thulium-doped fiber laser can be used. When using a thulium-doped fiber laser, a thulium-doped fiber optical amplifier is used instead of the EDFA. In this case, the range of the wavelength λ ₁ of the laser beam generated by the wavelength conversion element 167c by the sum frequency mixing of the laser beam L2 and the laser beam L3 is a wavelength range in which YDFA and EDFA can be amplified or YDFA and thulium-doped It is only necessary to satisfy 600 nm <λ ₁ <750 nm from the wavelength range that can be amplified by the fiber optical amplifier. In this case, if the final wavelength is 190 nm to 200 nm, the range of the wavelength λ ₃ of the light generated by the wavelength conversion element 167d is 234 nm <λ ₃ <240 nm. Therefore, the range of λ ₂ of the wavelength of light generated by the wavelength conversion element 167b is 352 nm <λ ₂ <383 nm.

  In the above embodiment, when the deliquescence of the CLBO crystal and the BBO crystal becomes a problem, the ambient atmosphere is purged with nitrogen or dry air, or the temperature of the CLBO crystal and the BBO crystal is adjusted to a high temperature. Just do it.

  In the exposure apparatus 10 of the above embodiment, an excimer laser apparatus 20 schematically shown in FIG. 4 may be used instead of the laser apparatus 16. This excimer laser device 20 has a laser device 16 ′ as a master oscillator having the same configuration as the laser device 16, and a laser beam having a wavelength of 193.4 nm emitted from the laser device 16 ′ as a seed light. A master oscillator optical output amplifier (MOPO or MOPA) laser system comprising a gas laser chamber 18 as an optical output amplifier (Power Oscillator or Power Amplifier) to be amplified, and a control device 19 for controlling the laser device 16 ′ and the gas laser chamber 18. is there.

In this excimer laser device 20, a gas laser chamber (Power Oscillator (PO)) having a resonator is used as the gas laser chamber 18 in the same manner as a normal ArF excimer laser device. The gas laser chamber 18 is filled with Ar and F ₂ that are medium gases, Ne that is a buffer gas, and the like. The gas laser chamber 18 may be a gas laser chamber (Power Amplifier) having a configuration in which a resonator (a front mirror and a rear mirror or a narrowband module) serving as a resonator is removed from a normal ArF excimer laser device.

  In this excimer laser device 20, seed light having a high repetition frequency with a wavelength of 193.4 nm emitted from the laser device 16 ′ is power-amplified inside the gas laser chamber 18, and the amplified laser light with a wavelength of 193.4 nm is emitted. Is done. In the excimer laser device 20, pulsed light with excellent beam quality is stably supplied from the laser device 16 ′ to the gas laser chamber 18, so that ArF excimer laser light can be stably emitted. In the laser device 16 ′, a single wavelength oscillation laser (solid laser) is used as a light source, so that it is possible to oscillate a laser beam with a narrower band and a higher repetition frequency than a normal ArF excimer laser. It is. Therefore, in an exposure apparatus equipped with this excimer laser device 20 as an exposure light source, laser light having a narrow band and a high repetition frequency of 193.4 nm is emitted from the excimer laser device 20 toward the illumination optical system. Become. Thereby, the peak power of the pulse can be suppressed and damage to the optical element such as an exposure apparatus can be suppressed. Further, in the exposure apparatus, the above-described scanning exposure is performed using a laser beam having a high energy (high power) as a whole and a band narrowed to a level sufficient for lithography. Therefore, the pattern of the reticle R can be accurately formed in each shot area on the wafer W, and the throughput can be improved.

  Further, when a master oscillator optical output amplifier (MOPO or MOPA) laser system is configured as in the excimer laser apparatus 20, a plurality of, for example, two gas laser chambers 18 are arranged in parallel. For example, a configuration may be adopted in which pulsed laser light (seed light) from the laser device 16 ′ is incident at different timings, for example, supplied alternately. In this case, for example, the seed light from the solid-state laser device 16 ′ may be distributed to the two gas laser chambers 18 in units of one pulse or a plurality of pulses by an optical modulator (such as an acousto-optic modulator (AOM)). Alternatively, the seed light is branched and guided to the two gas laser chambers 18, and the timing at which the seed light is incident on the two gas laser chambers 18 by, for example, electro-optic modulators (EOM) provided in the two branch optical paths, respectively. You may control. In such a case, laser beams are oscillated from the two gas laser chambers 18 at different timings, and the laser beams are synthesized coaxially by, for example, a mirror or a polarization beam splitter, and output, so that the repetition frequency of the excimer laser device 20 is increased. Therefore, when it is desired to obtain the same power, the pulse peak power can be halved, which can further suppress damage to optical elements such as an exposure apparatus. On the other hand, when the peak power is kept the same, twice the power can be obtained.

  In the above-described MOPO or MOPA laser system, a plurality of, for example, two gas laser chambers (PO or PA) 18 are arranged in series with respect to one solid-state laser device 16 ′, and the discharge timing in the two gas laser chambers 18. It is good also as doubling the repetition frequency of the excimer laser apparatus 20 by making these differ.

  In the above-described MOPO or MOPA laser system, a plurality of pulsed laser beams (seed beams) emitted from the solid-state laser device 16 'are incident at different timings during one discharge of the gas laser chamber (PO or PA) 18. You may let them. In this case, for example, the pulse laser beam (seed light) is divided into a plurality of pieces in the solid-state laser device 16 ′ and divided by a plurality of fibers having different lengths or a time division multiplexer (TDM). The plurality of pulsed laser beams may be delayed from each other and incident on the gas laser chamber 18. Alternatively, a plurality of solid-state laser devices 16 ′ are arranged in parallel, and a plurality of pulsed laser beams emitted from the plurality of solid-state laser devices 16 ′ with a predetermined time shift are supplied to the gas laser chamber 18 by controlling the oscillation timing, for example. It may be incident. In such a case, the pulse interval of the plurality of, for example, two pulse laser beams (seed light) incident on the gas laser chamber 18 during one discharge is made sufficiently shorter than the discharge time (for example, 20 ns) of the gas laser chamber 18. (For example, about 10 ns or less) is preferable, and the same effect as that obtained by doubling the peak power of the solid-state laser device 16 ′ can be obtained. In this laser system, the main oscillator (MO) 16 is not limited to the solid-state laser device, and other laser devices may be used.

  In the above embodiment, the case where the laser apparatus according to the present invention is applied to a step-and-scan type scanning exposure apparatus has been described. However, the present invention is not limited to this, and the stationary exposure type, for example, step-and-repeat, is used. The present invention can be applied to a proximity type exposure apparatus, a mirror projection aligner, etc. as well as an exposure apparatus of the type or step-and-stitch type. In addition, the present invention is also applied to an immersion type exposure apparatus disclosed in, for example, International Publication No. 99/49504 pamphlet, in which a liquid (for example, pure water) is filled between the projection optical system PL and the wafer. can do. Furthermore, as disclosed in, for example, International Publication No. 2001/035168, an exposure apparatus that forms line and space patterns on a wafer by forming interference fringes on the wafer, for example, Japanese Translation of PCT International Publication No. 2004-2004. As disclosed in Japanese Patent No. 5185050 (corresponding US Pat. No. 6,611,316), two reticle patterns are synthesized on a wafer via a projection optical system, and 1 on the wafer by one scanning exposure. The present invention can also be applied to an exposure apparatus that double-exposes two shot areas almost simultaneously.

  In addition, the exposure apparatus of the above embodiment has an exposure position where a reticle pattern is transferred via a projection optical system, as disclosed in, for example, Japanese Patent Application Laid-Open No. 10-214783 and International Publication WO98 / 40791. Alternatively, a twin wafer stage type in which a wafer stage is arranged at each of the measurement positions (alignment positions) where mark detection by the wafer alignment system is performed, and the exposure operation and the measurement operation can be performed substantially in parallel. Furthermore, as disclosed in, for example, JP-A-11-135400, JP-A-2000-164504, etc., a reference member that is movable independently of the wafer stage and on which a reference mark is formed and / or various photoelectric devices. The present invention can also be applied to an exposure apparatus including a measurement stage equipped with a sensor.

  In the above embodiment, a light transmissive mask (reticle) in which a predetermined light shielding pattern (or phase pattern / dimming pattern) is formed on a light transmissive substrate is used. Instead of this reticle, for example, As disclosed in US Pat. No. 6,778,257, an electronic mask (also called a variable shaping mask) that forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed. For example, a DMD (Digital Micro-mirror Device) which is a kind of non-light-emitting image display element (spatial light modulator) may be used.

  In the semiconductor device, a step of designing a function / performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and executing the above-described exposure method by the exposure apparatus of the above-described embodiment. The wafer is manufactured through a lithography step for transferring a reticle pattern onto a wafer, a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like. In this case, in the lithography step, the exposure method described above is executed using the exposure apparatus of the above embodiment, and a device pattern is formed on the wafer. Therefore, a highly integrated device can be manufactured with high productivity.

  Heretofore, an example in which the laser device or the excimer laser device according to the present invention is used as a laser device that generates illumination light for exposure has been described. However, light having substantially the same wavelength as the illumination light for exposure is required. Used as a laser device for reticle alignment, or a laser device for an aerial image detection system for detecting a projected image of a mark arranged on an object plane or an image plane of a projection optical system to obtain optical characteristics of the projection optical system It is also possible.

  The laser apparatus or excimer laser apparatus according to the present invention is an apparatus (device manufacturing apparatus, lithographic apparatus) used for a device manufacturing process other than an exposure apparatus, for example, a part of a circuit pattern formed on a wafer ( The present invention can also be applied to a laser repair apparatus used for cutting a fuse or the like, an inspection apparatus for inspecting a reticle pattern, or a pattern formed on a wafer. The laser device or excimer laser device according to the present invention can also be used in other processing devices such as polymer crystal processing devices.

  In addition, the laser apparatus or the excimer laser apparatus according to the present invention performs, for example, ablation of the surface by irradiating the cornea with laser light (or ablation inside the incised cornea) to correct the curvature or unevenness of the cornea and correct myopia. It can be used as a laser apparatus used in a laser treatment apparatus that performs treatment such as astigmatism. Further, the laser apparatus or the excimer laser apparatus according to the present invention can be used as a laser apparatus in an optical inspection apparatus such as a mask defect inspection apparatus. Since both apparatuses include the laser apparatus or excimer laser apparatus according to the present invention, it is possible to stably irradiate an object with excimer laser light having a predetermined wavelength via an optical system.

  The laser device of the present invention can also be used for optical adjustment (such as optical axis alignment) or inspection of an optical system such as the projection optical system in the above embodiment.

  As described above, the laser device and the light generation method of the present invention are suitable for emitting laser light having a predetermined wavelength with excellent beam quality. The excimer laser device of the present invention is suitable for emitting excimer laser light having a high repetition frequency. In addition, the light irradiation apparatus and the light irradiation method of the present invention are suitable for irradiating an object (irradiation target) with laser light having excellent beam quality.

It is a figure which shows schematically the structure of the exposure apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the laser apparatus of FIG. It is an enlarged view which takes out and shows the wavelength conversion part of FIG. It is a block diagram which shows typically the structure of the excimer laser apparatus which concerns on another embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Exposure apparatus (light irradiation apparatus), 16, 16 '... Laser apparatus, 18 ... Gas laser chamber, 20 ... Excimer laser apparatus, 160 ... Wavelength conversion part, 164a-164d ... Laser light source, 165a-165d ... Optical amplifier, 167a ˜167e wavelength conversion element, W wafer (object).

Claims (42)

A laser device that emits laser light of a predetermined wavelength,
First and second laser light sources that respectively generate first and second laser beams having different wavelengths;
A laser beam having the predetermined wavelength is generated through a plurality of stages of wavelength conversion using the first and second laser beams, and a set of wavelength conversion elements arranged without passing through a multiplexing optical element is finalized. And a wavelength conversion unit included in the stage.   The wavelength conversion unit includes a first conversion unit that generates a third laser beam by wavelength conversion using the first and second laser beams, and the third laser beam is the set of wavelength converters. The laser device according to claim 1, which is incident on the element.   The wavelength conversion unit further includes a second conversion unit that generates a fourth laser beam by wavelength conversion using the first laser beam, and the fourth laser beam is the set of wavelength conversion elements. The laser device according to claim 2, which is incident on the laser beam.   The second conversion unit includes a plurality of wavelength conversion elements that generate harmonics of the first laser light as the fourth laser light by multiple-stage wavelength conversion using the first laser light. 4. The laser device according to 3.   The wavelength conversion unit includes the set of wavelength conversion elements, and includes a plurality of stages of wavelength conversion including wavelength conversion for generating a fifth laser beam using the third laser beam and the fourth laser beam. The laser device according to claim 3, further comprising a third conversion unit that performs the operation.   The set of wavelength conversion elements performs sum frequency mixing of the third laser beam and the fourth laser beam to generate a fifth laser beam having a wavelength in the range of greater than 220 nm and less than 250 nm. The laser device according to claim 5, comprising an element.   The set of wavelength conversion elements further includes another wavelength conversion element that generates laser light of the predetermined wavelength by wavelength conversion using the fifth laser light and the first laser light. The laser apparatus described.   The said 1st conversion part contains the wavelength conversion element which performs the sum frequency mixing of the said 1st laser beam and the said 2nd laser beam, and generate | occur | produces the said 3rd laser beam. The laser device according to item.   The laser device according to any one of claims 2 to 8, wherein the third laser beam is a laser beam having a wavelength in a range greater than 600 nm and smaller than 750 nm. The first laser light source generates a first laser beam having a wavelength of 1.0 to 1.2 μm,
10. The laser device according to claim 1, wherein the second laser light source generates a second laser beam having a wavelength of 1.5 to 2.1 μm. The laser device according to claim 1, wherein the set of wavelength conversion elements is a nonlinear optical element made of a CsLiB ₆ O ₁₀ crystal. A laser device that emits laser light of a predetermined wavelength,
A first laser light source for generating a first laser beam having a wavelength of 1.0 to 1.2 μm;
A second laser light source for generating a second laser light having a wavelength of 1.5 to 2.1 μm;
The laser beam having the predetermined wavelength is generated through a plurality of stages of wavelength conversion using the first and second laser beams, and the sum frequency mixing of the first laser beam and the second laser beam is performed. And a wavelength conversion unit including a first conversion unit that generates a third laser beam.   The wavelength conversion unit includes a second conversion unit that generates a fourth laser beam by wavelength conversion using the first laser beam, and a wavelength conversion that uses the third laser beam and the fourth laser beam. The laser device according to claim 12, further comprising: a third conversion unit including a wavelength conversion element that generates a fifth laser beam by the step.   The third conversion unit further includes another wavelength conversion element that passes through the wavelength conversion element and in which at least one of the first laser beam and its harmonics enters together with the fifth laser beam. The laser device described in 1. The fifth laser light is light having a wavelength in a range larger than 220 nm and smaller than 250 nm,
The laser device according to claim 14, wherein the another wavelength conversion element generates the laser beam having the predetermined wavelength by sum frequency mixing of the fifth laser beam and the first laser beam.   The laser device according to any one of claims 12 to 15, wherein the third laser light is light having a wavelength in a range larger than 600 nm and smaller than 750 nm. A laser device that emits laser light of a predetermined wavelength,
First and second laser light sources that respectively generate first and second laser beams having different wavelengths;
The laser beam having the predetermined wavelength is generated through a plurality of stages of wavelength conversion using the first and second laser beams, and the sum frequency mixing of the first laser beam and the second laser beam is performed. And a wavelength conversion unit including a first conversion unit that generates a third laser beam having a wavelength in the range of greater than 600 nm and less than 750 nm.   The wavelength conversion unit further includes a second conversion unit that performs wavelength conversion using the first laser beam and generates a fourth laser beam that is a harmonic of the first laser beam. The laser apparatus described.   The wavelength conversion unit performs sum frequency mixing of the third laser beam and the fourth laser beam to generate a fifth laser beam having a wavelength in a range greater than 220 nm and less than 250 nm. The laser apparatus according to claim 18, further comprising a third conversion unit that generates the laser light having the predetermined wavelength by sum frequency mixing of the laser light and the first laser light.   Amplification including a first fiber amplifier for amplifying the first laser light generated by the first laser light source and a second fiber amplifier for amplifying the second laser light generated by the second laser light source The laser device according to claim 1, further comprising a unit. The first laser light source is an ytterbium-doped fiber laser;
The laser device according to any one of claims 1 to 20, wherein the second laser light source is an erbium-doped fiber laser.   The laser device according to any one of claims 1 to 21, wherein the laser beam having the predetermined wavelength is a laser beam having substantially the same wavelength as the ArF excimer laser beam. A light irradiation device for irradiating a target with light,
A laser device according to any one of claims 1 to 22;
An optical system through which a laser beam emitted from the laser device toward the object passes. An excimer laser device that emits excimer laser light,
A master oscillator comprising the laser device according to any one of claims 1 to 22;
An excimer laser apparatus comprising: a gas laser chamber that uses laser light output from the main oscillator as seed light and amplifies the seed light.   25. The excimer laser device according to claim 24, wherein a plurality of gas laser chambers are provided, and the plurality of gas laser chambers oscillate laser light obtained by amplifying the seed light at different timings.   The excimer laser device according to claim 25, wherein the plurality of gas laser chambers are provided in parallel, and the seed light is incident at different timings. A light irradiation device for irradiating a target with light,
An excimer laser device according to any one of claims 24 to 26;
An optical system through which a laser beam emitted from the excimer laser device toward the object passes.   The light irradiation apparatus according to claim 23 or 27, wherein the object is an object having a pattern. An exposure apparatus that exposes an object to form a pattern on the object,
A laser device according to any one of claims 1 to 22;
And an optical system through which a laser beam emitted from the laser device toward the object passes. A light generation method for generating laser light of a predetermined wavelength,
Generating first and second laser beams having different wavelengths from the first and second laser light sources, respectively;
A step of performing a plurality of stages of wavelength conversion using the first and second laser beams by a wavelength converter having a set of wavelength converters arranged at the final stage without passing through a multiplexing optical element; A light generation method comprising:   In the step of performing wavelength conversion, a first conversion for generating a third laser beam by wavelength conversion using the first and second laser beams, and a fourth by wavelength conversion using the first laser beam. After the second conversion that generates the laser beam and the fifth laser beam by the wavelength conversion using the third laser beam and the fourth laser beam by the pair of wavelength conversion elements, 31. The light generation method according to claim 30, wherein a third conversion for generating a laser beam having the predetermined wavelength is performed by wavelength conversion using a fifth laser beam and the first laser beam. A light generation method for generating laser light of a predetermined wavelength,
Generating a first laser beam having a wavelength of 1.0 to 1.2 μm and a second laser beam having a wavelength of 1.5 to 2.1 μm from the first and second laser light sources, respectively;
And a step of performing wavelength conversion in a plurality of stages including wavelength conversion for generating a third laser beam by performing sum frequency mixing of the first laser beam and the second laser beam. A light generation method for generating laser light of a predetermined wavelength,
Generating first and second laser beams having different wavelengths from the first and second laser light sources, respectively;
Performs multi-stage wavelength conversion including first conversion that performs sum frequency mixing of the first laser beam and the second laser beam to generate a third laser beam having a wavelength in the range greater than 600 nm and less than 750 nm. And a light generation method comprising:   The step of performing the wavelength conversion further performs second conversion for performing wavelength conversion using the first laser beam to generate a fourth laser beam that is a harmonic of the first laser beam. The light generation method described in 1.   In the wavelength conversion step, sum frequency mixing of the third laser beam and the fourth laser beam is performed to generate a fifth laser beam having a wavelength in a range greater than 220 nm and less than 250 nm, 35. The light generation method according to claim 34, further comprising performing third conversion for generating laser light of the predetermined wavelength by sum frequency mixing of laser light of 5 and the first laser light. An excimer laser light generation method for generating excimer laser light of a predetermined wavelength,
A first step of generating laser light of the predetermined wavelength by the light generation method according to any one of claims 30 to 35;
A second step of causing the laser light to enter the gas laser chamber as seed light and amplifying the seed light in the gas laser chamber.   37. The excimer laser light generation method according to claim 36, wherein, in the second step, the plurality of gas laser chambers oscillate laser light obtained by amplifying the seed light at different timings.   38. The excimer laser light generation method according to claim 37, wherein the plurality of gas laser chambers are provided in parallel, and the seed light is incident at different timings. A light irradiation method for irradiating an object with light,
A step of generating laser light by the light generation method according to any one of claims 30 to 35;
Emitting the laser light toward the object through an optical system.   40. The light irradiation method according to claim 39, wherein the object is an object on which a pattern is formed. An exposure method for exposing an object to form a pattern on the object,
A step of generating laser light by the light generation method according to any one of claims 30 to 35;
Emitting the laser beam toward the object through an optical system.   42. A device manufacturing method including a lithography step of forming a pattern on an object using the exposure method according to claim 41.

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