Wavelength conversion system, solid-state laser system, and method for manufacturing electronic devices

Abstract

A wavelength conversion system according to one aspect of the present disclosure comprises: a first non-linear optical crystal (51) on which first light (B1) having a first wavelength is incident, and which outputs second light (B2) having a second wavelength that is a second harmonic of the first light; a second non-linear optical crystal (52) on which the second light (B2) and third light (B3) having a third wavelength are incident, and which outputs the third light (B3) and fourth light (B4) having a fourth wavelength that is the sum frequency light of the second light and the third light; a third non-linear optical crystal (53) on which the third light (B3) and the fourth light (B4) are incident, and which outputs fifth light (B5) having a fifth wavelength that is the sum frequency light of the third light and the fourth light; a light condensing optical system (55a) which causes the first light (B1) to be incident on the first non-linear optical crystal (51) such that the beam waist position of the second light (B2) is disposed inside the second non-linear optical crystal (52). The first non-linear optical crystal (51) is disposed in a range within the Rayleigh length (zR2) of the second light from the beam waist position (P2) of the second light, and the third non-linear optical system (53) is disposed in a range within the Rayleigh length (zR4) of the fourth light from the beam waist position (P2) of the second light.

Description

[Technical Field]

[0001] This disclosure relates to a wavelength conversion system, a solid-state laser system, and a method for manufacturing electronic devices. [Background technology]

[0002] In recent years, semiconductor lithography equipment has been required to improve resolution as semiconductor integrated circuits become smaller and more integrated. Therefore, efforts are being made to shorten the wavelength of light emitted from lithography light sources. For example, gas laser equipment used for lithography includes KrF excimer laser equipment that outputs laser light with a wavelength of approximately 248 nm, and ArF excimer laser equipment that outputs laser light with a wavelength of approximately 193.4 nm.

[0003] The spectral linewidth of the spontaneously emitted light from KrF and ArF excimer laser systems is broad, ranging from 350 to 400 pm. Therefore, when a projection lens is constructed using a material that transmits ultraviolet light, such as KrF and ArF laser light, chromatic aberration may occur. As a result, resolution may decrease. Therefore, it is necessary to narrow the spectral linewidth of the laser light output from the gas laser system until chromatic aberration is negligible. For this reason, the laser resonator of a gas laser system contains a line-narrowing module (Line Narrowing Module) that includes narrowing elements (etalons, gratings, etc.) to narrow the spectral linewidth. It may be possible to equip such a device. A gas laser device that narrows the spectral linewidth in this way is called a narrowband gas laser device. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] U.S. Patent No. 11226536 [Patent Document 2] Summary of Japanese Patent Publication No. 2007-140564

[0005] A wavelength conversion system according to one aspect of the present disclosure comprises: a first nonlinear optical crystal into which a first light having a first wavelength is incident and which outputs a second light having a second wavelength that is the second harmonic of the first light; a second nonlinear optical crystal into which a third light having the second light and a third wavelength is incident and which outputs a fourth light having a fourth wavelength that is the sum frequency of the second and third light, and the third light; a third nonlinear optical crystal into which the third and fourth light are incident and which outputs a fifth light having a fifth wavelength that is the sum frequency of the third and fourth light; and a focusing optical system that causes the first light to be incident on the first nonlinear optical crystal such that the beam waist position of the second light is located within the second nonlinear optical crystal, wherein the first nonlinear optical crystal is located within the Rayleigh length of the second light from the beam waist position of the second light, and the third nonlinear optical crystal is located within the Rayleigh length of the fourth light from the beam waist position of the second light.

[0006] A solid-state laser system according to one aspect of the present disclosure comprises: a first nonlinear optical crystal into which a first light having a first wavelength is incident and which outputs a second light having a second wavelength that is the second harmonic of the first light; a second nonlinear optical crystal into which a third light having a second and a third wavelength is incident and which outputs a fourth light having a fourth wavelength that is the sum frequency of the second and third light, and the third light; a third nonlinear optical crystal into which the third and fourth light are incident and which outputs a fifth light having a fifth wavelength that is the sum frequency of the third and fourth light; and a focusing optical system that causes the first light to be incident on the first nonlinear optical crystal such that the beam waist position of the second light is located within the second nonlinear optical crystal, the first The wavelength conversion system includes a nonlinear optical crystal positioned within the range from the beam waist position of the second light to the Rayleigh length of the second light, and a third nonlinear optical crystal positioned within the range from the beam waist position of the second light to the Rayleigh length of the fourth light; a signal laser device that outputs signal laser light; an amplification system that pulses the signal laser light based on pump laser light and outputs the pulsed amplified signal laser light as the third light to the wavelength conversion system; and a pump laser device that generates pump laser light and the first light, outputs the pump laser light to the amplification system, and outputs the first light to the wavelength conversion system.

[0007] A method for manufacturing an electronic device according to one aspect of the present disclosure includes: a first nonlinear optical crystal into which a first light having a first wavelength is incident and which outputs a second light having a second wavelength that is the second harmonic of the first light; a second nonlinear optical crystal into which a second light and a third light having a third wavelength are incident and which outputs a fourth light having a fourth wavelength that is the sum frequency of the second and third light and the third light; a third nonlinear optical crystal into which a third light and a fourth light are incident and which outputs a fifth light having a fifth wavelength that is the sum frequency of the third and fourth light; and a beam cloth of the second light within the second nonlinear optical crystal. The solid-state laser system includes a focusing optical system that incidents a first light onto a first nonlinear optical crystal such that a beam waist position is set, the first nonlinear optical crystal is positioned within the Rayleigh length of the second light from the beam waist position of the second light, and the third nonlinear optical crystal is positioned within the Rayleigh length of the fourth light from the beam waist position of the second light. The system generates laser light by a wavelength conversion system, outputs the laser light to an exposure apparatus, and exposes a photosensitive substrate with the laser light in the exposure apparatus to manufacture an electronic device. [Brief explanation of the drawing]

[0008] Some embodiments of this disclosure are described below, merely as examples, with reference to the accompanying drawings. [Figure 1] Figure 1 is a schematic diagram showing the configuration of a solid-state laser system related to a comparative example. [Figure 2] Figure 2 is a schematic diagram showing the configuration of a wavelength conversion system related to a comparative example. [Figure 3] Figure 3 is a schematic diagram showing a cell in which a nonlinear optical crystal is arranged inside. [Figure 4] Figure 4 is a schematic diagram showing the configuration of the wavelength conversion system according to the first embodiment. [Figure 5] Figure 5 shows the relationship between Rayleigh length and beam waist radius. [Figure 6] Figure 6 is a schematic diagram showing the configuration of the wavelength conversion system according to the second embodiment. [Figure 7] Figure 7 is a schematic diagram showing the configuration of the periscope optical system. [Figure 8] FIG. 8 is a diagram schematically showing the configuration of a wavelength conversion system according to the fourth embodiment. [Figure 9] FIG. 9 is a diagram schematically showing a configuration example of an exposure apparatus. Embodiment

[0009] <Content> 1. Comparative Example 1.1 Solid Laser System 1.1.1 Configuration 1.1.2 Operation 1.2 Wavelength Conversion System 1.2.1 Configuration and Operation 1.3 Problem 2. First Embodiment 2.1 Configuration and Operation 2.2 Relationship between Rayleigh Length and Numerical Aperture 2.3 Effect 3. Second Embodiment 3.1 Configuration and Operation 3.2 Effect 4. Third Embodiment 4.1 Configuration and Operation 4.2 Effect 5. Fourth Embodiment 5.1 Configuration and Operation 5.2 Effect 6. Method for Manufacturing an Electronic Device

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below show some examples of the present disclosure and do not limit the content of the present disclosure. Also, not all of the configurations and operations described in the embodiments are essential as the configurations and operations of the present disclosure. Note that the same reference numerals are assigned to the same components, and redundant descriptions are omitted.

[0011] 1. Comparative Example First, a comparative example of the present disclosure will be described. The comparative example of the present disclosure is a form that the applicant recognizes as being known only to the applicant and is not a known example recognized by the applicant.

[0012] 1.1 Solid-state laser systems 1.1.1 Configuration Figure 1 schematically shows the configuration of a solid-state laser system 10 according to a comparative example. The solid-state laser system 10 includes a signal laser device 2, an amplification system 3, a pump laser device 4, a wavelength conversion system 5, and a solid-state laser control unit 6. The solid-state laser system 10 outputs pulsed laser light with a wavelength of approximately 193.4 nm.

[0013] The signal laser device 2 includes a semiconductor laser 21 and a solid-state amplifier 22. The semiconductor laser 21 oscillates in single longitudinal mode as a continuous wave (CW) with a wavelength of approximately 1553 nm. The solid-state amplifier 22 outputs CW laser light. The solid-state amplifier 22 is an amplifier that includes a semiconductor optical amplifier and amplifies the CW laser light output from the semiconductor laser 21. The CW laser light with a wavelength of approximately 1553 nm amplified by the solid-state amplifier 22 is incident on the amplification system 3 as signal laser light S.

[0014] The pump laser device 4 includes a semiconductor laser 41, a solid-state amplifier 42, an LBO (LiB3O5) crystal 43, and a dichroic mirror (DM) 44. The conductive laser 41 oscillates in single longitudinal mode in CW mode and outputs CW laser light with a wavelength of approximately 1030 nm. The solid-state amplifier 42 is an amplifier that includes a semiconductor optical amplifier and a Yb-doped YAG crystal, and pulses the CW laser light output from the semiconductor laser 41.

[0015] The LBO crystal 43 is a nonlinear optical crystal that converts the wavelength of pulsed laser light with a wavelength of approximately 1030 nm, which is generated by pulse amplification by the solid-state amplifier 42, to generate pulsed laser light with a wavelength of approximately 515 nm, which is the second harmonic.

[0016] DM44 is positioned downstream of the LBO crystal 43 and highly reflects pulsed laser light with a wavelength of approximately 1030 nm that was not wavelength-converted by the LBO crystal 43, while highly transmitting pulsed laser light with a wavelength of approximately 515 nm that was incident from the LBO crystal 43. The pulsed laser light highly reflected by DM44 is output from the pump laser device 4 and incident on the amplification system 3 as pump laser light P. The pulsed laser light that has been highly transmitted through DM44 is output from the pump laser device 4 and incident on the wavelength conversion system 5 as the first pulsed laser light PL1.

[0017] The amplification system 3 includes an optical parametric amplifier (OPA). The OPA is an amplifier that includes, for example, a periodically polled lithium niobate crystal (PPLN) or a periodically polled potassium titanyl phosphate crystal (PPKTP). The OPA pulses the signal laser light S incident from the signal laser device 2 based on the pump laser light P incident from the pump laser device 4. The pulsed amplified signal laser light S is output from the amplification system 3 and incident as a second pulse laser light PL2 into the wavelength conversion system 5.

[0018] Wavelength conversion system 5 is the first CLBO(CsLiB6O 10 The crystal includes 51, a second CLBO crystal 52, a third CLBO crystal 53, and DM54a. The first CLBO crystal 51 is a nonlinear optical crystal that wavelength-converts the first pulsed laser light PL1 incident from the pump laser device 4 and generates and outputs ultraviolet pulsed laser light with a wavelength of approximately 257.5 nm, which is the second harmonic of the first pulsed laser light PL1.

[0019] DM54a is positioned downstream of the first CLBO crystal 51 and highly reflects the second pulsed laser light PL2 incident from the amplification system 3 and highly transmits the ultraviolet pulsed laser light incident from the first CLBO crystal 51. Furthermore, DM54a is positioned so that the highly reflected second pulsed laser light PL2 and the highly transmitted ultraviolet pulsed laser light are incident coaxially on the second CLBO crystal 52.

[0020] The second CLBO crystal 52 and the third CLBO crystal 53 are arranged in series, and by performing two sum frequency generation operations, a pulsed laser light PL with a wavelength of approximately 193.4 nm is generated and output.

[0021] The solid-state laser control unit 6 is composed of a processor and is connected to the signal laser device 2, the pump laser device 4, and the wavelength conversion system 5. The solid-state laser control unit 6 is connected to the laser control unit 12, which is located outside the solid-state laser system 10.

[0022] 1.1.2 Operation Next, the operation of the solid-state laser system 10 in the comparative example will be described. The solid-state laser control unit 6 controls the current value of the semiconductor laser 41 of the pump laser device 4 to cause it to oscillate in CW mode and output CW laser light with a wavelength of approximately 1030 nm. The solid-state laser control unit 6 also pulses the CW laser light output from the semiconductor laser 41 using the solid-state amplifier 42.

[0023] The LBO crystal 43 converts the pulsed laser light with a wavelength of approximately 1030 nm, generated by pulse amplification by the solid-state amplifier 42, into pulsed laser light with a wavelength of approximately 515 nm. The pulsed laser light with a wavelength of approximately 515 nm transmits highly through the DM 44 and is incident on the wavelength conversion system 5 as the first pulsed laser light PL1. The pulsed laser light with a wavelength of approximately 1030 nm that was not wavelength-converted by the LBO crystal 43 is highly reflected by the DM 44 and is incident on the amplification system 3 as the pump laser light P.

[0024] The solid-state laser control unit 6 controls the current value of the semiconductor laser 21 of the signal laser device 2 to cause it to oscillate in continuous wave (CW), thereby outputting CW laser light with a wavelength of approximately 1553 nm. The solid-state laser control unit 6 also amplifies the CW laser light output from the semiconductor laser 21 using a solid-state amplifier 22. As a result, CW laser light with a wavelength of approximately 1553 nm is output from the signal laser device 2 and incident on the amplification system 3 as signal laser light S.

[0025] The amplification system 3 pulses and amplifies the signal laser beam S based on the pump laser beam P. The pulsed-amplified signal laser beam S is then injected into the wavelength conversion system 5 as a second pulsed laser beam PL2.

[0026] In the wavelength conversion system 5, the first pulsed laser light PL1 is converted into ultraviolet pulsed laser light with a wavelength of approximately 257.5 nm by the first CLBO crystal 51. The ultraviolet pulsed laser light with a wavelength of approximately 257.5 nm transmits highly through DM54a and is incident on the second CLBO crystal 52. The second pulsed laser light PL2 is highly reflected by DM54a and is incident on the second CLBO crystal 52. The second CLBO crystal 52 generates and outputs ultraviolet pulsed laser light with a wavelength of approximately 220.9 nm, which is the sum frequency of the second pulsed laser light PL2 and the ultraviolet pulsed laser light with a wavelength of approximately 257.5 nm. The second CLBO crystal 52 also outputs the second pulsed laser light PL2 that has not been wavelength converted.

[0027] The second pulsed laser beam PL2 output from the second CLBO crystal 52 and the ultraviolet pulsed laser beam with a wavelength of approximately 220.9 nm are incident on the third CLBO crystal 53 coaxially. The third CLBO crystal 53 generates and outputs a pulsed laser beam PL with a wavelength of approximately 193.4 nm, which is the sum frequency of the second pulsed laser beam PL2 and the ultraviolet pulsed laser beam with a wavelength of approximately 220.9 nm. The pulsed laser beam PL is output from the solid-state laser system 10.

[0028] The pulsed laser light PL output from the solid-state laser system 10 may be amplified by an excimer amplifier (not shown).

[0029] 1.2 Wavelength Conversion System 1.2.1 Structure and Operation Next, the configuration and operation of the wavelength conversion system 5 according to the comparative example will be explained in more detail using Figure 2. Figure 2 shows the configuration of the wavelength conversion system 5 according to the comparative example. In addition to the first to third CLBO crystals 51 to 53 and DM 54a described above, the wavelength conversion system 5 includes DM 54b, 54c, lenses 55a to 55c, high-reflection mirrors 56a, 56b, and a half-wave plate 57.

[0030] The first to third CLBO crystals 51 to 53 are nonlinear optical crystals having a type-1 phase matching condition. That is, the first to third CLBO crystals 51 to 53 are configured such that the angle between the optical axis and the optical path axis of the incident laser light is a phase matching angle that satisfies the type-1 phase matching condition.

[0031] Lens 55a is positioned on the optical path of the first light B1 incident on the wavelength conversion system 5, and upstream of the first CLBO crystal 51. The first light B1 is the first pulsed laser light PL1 described above. The first wavelength λ1 of the first light B1 is approximately 515 nm. Lens 55a focuses the first light B1 such that the beam waist position P1 of the first light B1 is inside the first CLBO crystal 51.

[0032] The first CLBO crystal 51 is positioned such that its crystal center is at the beam waist position P1. The first CLBO crystal 51 converts the first light B1 having a first wavelength λ1 into a second light B2 having a second wavelength λ2, which is the second harmonic of the first light B1, and outputs it. The second wavelength λ2 is approximately 257.5 nm. The second light B2 is ultraviolet pulsed laser light with the aforementioned wavelength of approximately 257.5 nm. The first CLBO crystal 51 is an example of the "first nonlinear optical crystal" related to the technology of this disclosure.

[0033] The beam waist position of the second light B2 is the same as the beam waist position P1 of the first light B1. In other words, the second light B2 emitted from the first CLBO crystal 51 is diffuse light that diffuses from the beam waist position P1.

[0034] Lens 55b is positioned on the optical path of the third light B3 incident on the wavelength conversion system 5, and upstream of DM54a. The third light B3 is the second pulsed laser light PL2 described above. The third wavelength λ3 of the third light B3 is approximately 1553 nm. Lens 55b focuses the third light B3 via DM54a such that the beam waist position P3a of the third light B3 is inside the second CLBO crystal 52.

[0035] DM54a is coated with a film that highly transmits the second light B2 and highly reflects the third light B3. The third light B3, which enters DM54a from lens 55b and is highly reflected by DM54a, is focused into the second CLBO crystal 52.

[0036] The second CLBO crystal 52 is positioned such that its crystal center is at the beam waist position P3a. The second CLBO crystal 52 generates and outputs a fourth light B4, which is the sum frequency light of the second light B2, which is highly transmitted through DM54a, and the third light B3, which is highly reflected by DM54a. The fourth wavelength λ4 of the fourth light B4 is approximately 220.9 nm. The second CLBO crystal 52 also outputs the third light B3, which has not undergone wavelength conversion. The second CLBO crystal 52 is an example of the "second nonlinear optical crystal" related to the technology of this disclosure.

[0037] The second light B2 and the third light B3 incident on the second CLBO crystal 52 are both linearly polarized. Since the second CLBO crystal 52 has a type-1 phase matching condition, the polarization direction of the second light B2 incident on the second CLBO crystal 52 must be parallel to the polarization direction of the third light B3. If the polarization direction of the second light B2 incident on the second CLBO crystal 52 is parallel to the polarization direction of the third light B3, then the polarization direction of the third light B3 output from the second CLBO crystal 52 and the polarization direction of the fourth light B4 are orthogonal.

[0038] Since the third CLBO crystal 53 has a type-1 phase matching condition, the polarization direction of the third light B3 incident on the third CLBO crystal 53 must be parallel to the polarization direction of the fourth light B4. Since the polarization direction of the third light B3 and the polarization direction of the fourth light B4 output from the second CLBO crystal 52 are orthogonal, it is necessary to rotate the polarization direction of either the third light B3 or the fourth light B4 by 90°.

[0039] DM54b, 54c, lens 55c, high-reflection mirrors 56a, 56b, and half-wave plate 57 constitute a polarization direction changing optical system 60. The polarization direction changing optical system 60 is positioned between the second CLBO crystal 52 and the third CLBO crystal 53. In this comparative example, the polarization direction changing optical system 60 rotates the polarization direction of the third light B3 by 90°, thereby making the polarization direction of the third light B3 parallel to the polarization direction of the fourth light B4.

[0040] DM54b and DM54c are coated with a film that transmits the fourth light B4 with high transparency and reflects the third light B3 with high transparency. DM54b is positioned downstream of the second CLBO crystal 52 and is an optical path splitter that splits the optical paths of the third light B3 and the fourth light B4 output from the second CLBO crystal 52. DM54c is positioned upstream of the third CLBO crystal 53 and is an optical path merger that merges the optical paths of the third light B3 and the fourth light B4, whose optical paths have been split by DM54b.

[0041] DM54b transmits the fourth light B4 emitted from the second CLBO crystal 52 with high transmittance. The fourth light B4, having transmitted with high transmittance through DM54b, then transmits with high transmittance through DM54c and enters the third CLBO crystal 53. DM54b also reflects the third light B3 emitted from the second CLBO crystal 52 with high reflectance.

[0042] The high-reflection mirror 56a is positioned on the optical path of the third light B3, which is highly reflected by DM54b, and reflects the third light B3 with high intensity. The lens 55c is positioned downstream of the high-reflection mirror 56a and focuses the third light B3 via the high-reflection mirror 56a and DM54c so that the beam waist position P3b of the third light B3, which is highly reflected by the high-reflection mirror 56a, is within the third CLBO crystal 53.

[0043] The high-reflection mirror 56b is positioned downstream of the lens 55c and highly reflects the third light B3. The half-wave plate 57 is positioned downstream of the high-reflection mirror 56b and rotates the polarization direction of the third light B3 highly reflected by the high-reflection mirror 56b by 90°.

[0044] DM54c is positioned downstream of the half-wave plate 57 and highly reflects the third light B3, whose polarization direction has been rotated by 90°, and directs it onto the third CLBO crystal 53. As a result, the polarization direction of the third light B3 incident on the third CLBO crystal 53 and the polarization direction of the fourth light B4 become parallel.

[0045] The third CLBO crystal 53 is positioned such that its crystal center is at the beam waist position P3b. The third CLBO crystal 53 generates and outputs fifth light B5, which is the sum frequency light of third light B3 and fourth light B4. Fifth light B5 is the pulsed laser light PL described above. The fifth wavelength λ5 of fifth light B5 is approximately 193.4 nm. The third CLBO crystal 53 is an example of the "third nonlinear optical crystal" related to the technology of this disclosure. The first to fifth wavelengths λ1 to λ5 have the relationship λ3 > λ1 > λ2 > λ4 > λ5.

[0046] The second CLBO crystal 52 is positioned within a range where the incident ultraviolet light, the second light B2, can be considered as parallel light. The third CLBO crystal 53 is positioned within a range where the incident ultraviolet light, the fourth light B4, can be considered as parallel light. Since the second light B2 and the fourth light B4 are diffuse light diffusing from the beam waist position P1, the second CLBO crystal 52 and the third CLBO crystal 53 are positioned downstream from the beam waist position P1 with a Rayleigh length z R1 It is positioned within a certain range. Rayleigh length represents the distance at which pulsed laser light can be considered as parallel light.

[0047] 1.3 Challenges Next, the problems of the wavelength conversion system 5 related to the comparative example will be explained. Since nonlinear optical crystals such as CLBO crystals are hygroscopic, they are placed inside the cell 70 as shown in Figure 3.

[0048] Cell 70 comprises a housing 71, an input window 72, an output window 73, a crystal holder 74, and a heater 75. The input window 72 and the output window 73 are mounted on the housing 71. The crystal holder 74 is located inside the housing 71 and holds a nonlinear optical crystal in the optical path of pulsed laser light passing through the input window 72 and the output window 73. The heater 75 is mounted on the crystal holder 74 and is connected to a heater power supply 76 located outside the cell 70. The heater 75 heats the nonlinear optical crystal.

[0049] The housing 71 is connected to a gas inlet pipe 77a for introducing a purge gas such as Ar gas into the housing 71, and a gas outlet pipe 77b for discharging the purge gas from inside the housing 71. The gas inlet pipe 77a is connected to a gas supply device 78a. The gas outlet pipe 77b is connected to a gas discharge device 78b.

[0050] Cell 70 is used while purging it with a purge gas and maintaining the temperature of the nonlinear optical crystal at approximately 150°C using heater 75. Therefore, in order to arrange the first to third CLBO crystals 51 to 53 in the wavelength conversion system 5, the optical path length for arranging cell 70 must be secured before and after the nonlinear optical crystal, taking into account the volume of cell 70.

[0051] It is conceivable to use a relay lens optical system to secure the optical path length required for positioning cell 70. However, if a relay lens optical system is used, the relay lens optical system must propagate pulsed laser light, which is ultraviolet light, and the lens will degrade due to the ultraviolet light. As a result, the lifespan of the wavelength conversion system 5 will be shortened. In addition, the absorption of ultraviolet light by the lens will cause a thermal lensing effect, resulting in changes in the beam diameter and beam waist position. Furthermore, surface reflection will occur at the lens, reducing the output of the pulsed laser light. For these reasons, the use of a relay lens optical system is undesirable.

[0052] From the viewpoint of improving the efficiency of wavelength conversion, it is preferable to arrange the multiple nonlinear optical crystals included in the wavelength conversion system 5 within a range of Rayleigh length from the beam waist position of the incident pulsed laser light. In the example shown in Figure 2, as described above, the second CLBO crystal 52 and the third CLBO crystal 53 are arranged downstream from the beam waist position P1 located at the crystal center of the first CLBO crystal 51, within a Rayleigh length z R1 They are placed within a certain range.

[0053] However, considering the volume of cell 70, it is difficult to position each nonlinear optical crystal within the Rayleigh length. In the example shown in Figure 2, considering the volume of cell 70, the Rayleigh length z is within the range from the first CLBO crystal 51. R1 It is difficult to place the second CLBO crystal 52 and the third CLBO crystal 53 within this range.

[0054] In other words, the wavelength conversion system 5, which has multiple nonlinear optical crystals with hygroscopic properties such as CLBO crystals, has the problem that the optical path length that allows for the arrangement of multiple nonlinear optical crystals is short, and the degree of design freedom is very low, from the viewpoint of improving the efficiency of wavelength conversion.

[0055] 2. First Embodiment Next, a solid-state laser system 10 according to the first embodiment of this disclosure will be described. The solid-state laser system 10 according to the first embodiment differs from the solid-state laser system 10 of the comparative example only in the configuration of the wavelength conversion system. In the following, the same reference numerals are used for components that are the same as those in the comparative example, and their descriptions are omitted as appropriate.

[0056] 2.1 Structure and Operation The configuration and operation of the wavelength conversion system 5a according to the first embodiment will be explained using Figure 4. Figure 4 shows the configuration of the wavelength conversion system 5a according to the first embodiment. The wavelength conversion system 5a, like the wavelength conversion system 5 according to the comparative example, includes first to third CLBO crystals 51 to 53, DMs 54a to 54c, lenses 55a to 55c, high-reflection mirrors 56a and 56b, and a half-wave plate 57.

[0057] In this embodiment, lens 55a causes the first light B1 to be incident on the first CLBO crystal 51 such that the beam waist position P2 of the second light B2 generated by the first CLBO crystal 51 is located within the second CLBO crystal 52. That is, by focusing the first light B1 with lens 55a, the second light B2 is focused into the second CLBO crystal 52. It is preferable that the second CLBO crystal 52 is positioned so that its crystal center is at the beam waist position P2. Lens 55a is an example of a "focusing optical system" according to the art of this disclosure. The focusing optical system is not limited to one lens, but may be composed of an optical system including two or more lenses, mirrors, etc.

[0058] In this embodiment, the beam waist position of the fourth light B4 generated by the second CLBO crystal 52 is the same as the beam waist position P2 of the second light B2. That is, the fourth light B4 output from the second CLBO crystal 52 becomes diffuse light diffusing from the beam waist position P2.

[0059] In this embodiment, the first CLBO crystal 51 is located upstream of the second CLBO crystal 52, and the Rayleigh length z of the second light B2 from the beam west position P2. R2 It is positioned within a range of [specify range]. Specifically, the surface 51a of the first CLBO crystal 51 to which light is incident is within the Rayleigh length z of the second beam B2 from the beam waist position P2. R2 The first CLBO crystal 51 is positioned so that it is within the specified range.

[0060] Furthermore, the third CLBO crystal 53 is located downstream of the second CLBO crystal 52, and the Rayleigh length z of the fourth beam B4 from the beam west position P2. R4 It is positioned within the range of the third CLBO crystal 53. Specifically, the surface 53a from which the light of the third CLBO crystal 53 is emitted is within the Rayleigh length z of the fourth beam B4 from the beam waist position P2. R4 The third CLBO crystal 53 is positioned so that it falls within the specified range.

[0061] 2.2 Relationship between Rayleigh length and numerical aperture Next, the relationship between the Rayleigh length and the numerical aperture will be described. FIG. 5 shows the relationship between the Rayleigh length z R and the beam waist radius ω when a laser beam, which is collimated light, is incident on the lens 90.

[0062] The beam waist of the laser beam focused by the lens 90 occurs at a position with a focal length f from the lens 90. The beam waist radius ω is the beam radius of the laser beam at the beam waist position. More specifically, the beam waist radius ω is the beam radius at a position where the radiation intensity is 1 / e 2 times the peak radiation intensity at the beam center.

[0063] The relationship between the Rayleigh length z R and the beam waist radius ω is expressed by the following equation (1). Here, λ is the wavelength of the parallel light incident on the lens 90.

[0064]

Equation

[0065] The relationship between the numerical aperture NA and the beam waist radius ω is expressed by the following equation (2). Here, n is the refractive index of the medium through which the laser beam propagates. θ is the beam divergence angle.

[0066]

Equation

[0067] When n = 1 and |θ| ≪ 1, the above equation (2) is expressed by the following equation (3).

[0068]

Equation

[0069] Also, according to the above equation (1), the beam waist radius ω is expressed by the following equation (4).

[0070]

Equation

[0071] As shown in Figure 4, if L1 is the distance from the light incident surface 51a of the first CLBO crystal 51 to the beam waist position P2, then the distance from the light incident surface 51a to the beam waist position P2 is the Rayleigh length z of the second beam B2. R2 In order to keep it within the range, the following equation (5) must be satisfied. Here, ω2 is the beam waist radius of the second light B2.

[0072]

number

[0073] According to equation (5) above, the beam waist radius ω2 of the second beam B2 must satisfy equation (6) below.

[0074]

number

[0075] According to equations (3) and (6) above, in order to satisfy equation (5) above, the numerical aperture NA2 of the second light B2 must satisfy equation (7) below.

[0076]

number

[0077] Furthermore, as shown in Figure 4, if L2 is the distance from the light-emitting surface 53a of the third CLBO crystal 53 to the beam waist position P2, then the distance from the light-emitting surface 53a to the beam waist position P2 is the Rayleigh length z of the fourth beam B4. R4 In order to keep it within the range, the following equation (8) must be satisfied. ω4 is the beam waist radius of the fourth light B4.

[0078]

number

[0079] Here, assuming ω4 = ω2, equation (8) above can be expressed as equation (9) below.

[0080]

number

[0081] Furthermore, we assume that the beam waist position of the first light B1 coincides with the beam waist position P2 of the second light B2, and that the beam waist radius ω1 of the first light B1 satisfies equation (10) below.

[0082]

number

[0083] In this case, the numerical aperture NA1 of the first light B1 is expressed by the following equation (11).

[0084]

number

[0085] Therefore, in this embodiment, the beam waist radius ω2 of the second light B2 should be set to satisfy equation (6) above with respect to distance L1, and the numerical aperture NA2 of the second light B2 should be set to satisfy equation (7) above. Furthermore, the lens 55a that focuses the first light B1 should satisfy equation (10) above for the beam waist radius ω1 of the first light B1, and the numerical aperture NA1 should be √2 times the numerical aperture NA2 of the second light B2.

[0086] In other words, a lens 55a having an numerical aperture NA1, as shown in equation (12) below, should be selected.

[0087]

number

[0088] 2.3 Effects As described above, in the wavelength conversion system 5a according to this embodiment, the lens 55a causes the first light B1 to be incident on the first CLBO crystal 51 such that the beam waist position P2 of the second light B2 generated in the first CLBO crystal 51 is located inside the second CLBO crystal 52. For this reason, the Rayleigh length z of the second light B2 is upstream from the beam waist position P2. R2 The first CLBO crystal 51 can be placed within the range of z. Also, the Rayleigh length z of the fourth beam B4 downstream from beam waist position P2. R4 The third CLBO crystal 53 can be placed within the range within this range. All of the first to third CLBO crystals 51 to 53 are located from beam waist position P2 to Rayleigh length z R2 ,z R4 By arranging them within the optical path length range specified by [the relevant standard], the wavelength conversion efficiency is improved.

[0089] Thus, according to this embodiment, the optical path length that allows for the arrangement of multiple nonlinear optical crystals is expanded from the viewpoint of improving the efficiency of wavelength conversion, and the design freedom of the wavelength conversion system 5a can be improved without reducing the wavelength conversion efficiency. As a result, each of the multiple nonlinear optical crystals can be arranged inside the cell without using a relay lens optical system.

[0090] 3. Second Embodiment Next, a solid-state laser system 10 according to a second embodiment of this disclosure will be described. The solid-state laser system 10 according to the second embodiment differs from the solid-state laser system 10 according to the first embodiment only in the configuration of the wavelength conversion system. In the following, the same reference numerals are used for components that are the same as in the first embodiment, and their descriptions are omitted as appropriate.

[0091] 3.1 Structure and Operation The configuration and operation of the wavelength conversion system 5b according to the second embodiment will be explained using Figure 6. Figure 6 shows the configuration of the wavelength conversion system 5b according to the second embodiment. The wavelength conversion system 5b includes first to third CLBO crystals 51 to 53, DMs 54a to 54e, lenses 55a to 55c, high-reflection mirrors 56b, half-wave plates 57, and dampers 58a to 58c. Similar to the first embodiment, the first to third CLBO crystals 51 to 53 are each nonlinear optical crystals having type-1 phase matching conditions.

[0092] In the first embodiment, the first to third CLBO crystals 51 to 53 are arranged in a linear fashion, but in this embodiment, the first to third CLBO crystals 51 to 53 are arranged in a non-linear fashion. In addition, in this embodiment, light that has not been wavelength-converted by the first to third CLBO crystals 51 to 53 is absorbed by the dampers 58a to 58c.

[0093] In this embodiment as well, the lens 55a causes the first light B1 to be incident on the first CLBO crystal 51 such that the beam waist position P2 of the second light B2 generated in the first CLBO crystal 51 is located inside the second CLBO crystal 52. The Rayleigh length z of the second light B2 is located upstream of the beam waist position P2 in the first CLBO crystal 51. R2 It is positioned within the range within [a certain range]. In addition, the third CLBO crystal 53 is positioned downstream from beam waist position P2, with the Rayleigh length z of the fourth beam B4. R It is arranged within a range of 4 or less. When the optical paths of the second light B2 and the fourth light B4 are bent as in this embodiment, the Rayleigh length z R2 ,z R4 This is defined by the optical path length along the bent optical path.

[0094] In this embodiment, DM54a is coated with a film that highly reflects the second light B2 and highly transmits the first light B1 and the third light B3. The second light B2, which is incident from lens 55a onto the first CLBO crystal 51 and generated in the first CLBO crystal 51, is highly reflected by DM54a and focused into the second CLBO crystal 52. The third light B3, which is incident from lens 55b onto DM54a, is highly transmitted through DM54a and focused into the second CLBO crystal 52.

[0095] The damper 58a is not wavelength-converted by the first CLBO crystal 51 and is positioned on the optical path of the first light B1, which has high transmittance through DM54a, and absorbs the first light B1.

[0096] The second CLBO crystal 52 is positioned in the optical path between the second light B2, which is highly reflected by DM54a, and the third light B3, which is highly transmitted through DM54a. Similar to the first embodiment, the second CLBO crystal 52 generates the fourth light B4, which is the sum frequency light of the second light B2 and the third light B3.

[0097] In this embodiment, the polarization direction changing optical system 60a is composed of DM54b~54d, lens 55c, high-reflection mirror 56b, and half-wave plate 57. The fourth light B4 output from the second CLBO crystal 52, and the second light B2 and third light B3 that were not wavelength-converted by the second CLBO crystal 52 are incident on the polarization direction changing optical system 60a.

[0098] Similar to the first embodiment, DM54b is an optical path splitting element. In this embodiment, DM54b is positioned downstream of the second CLBO crystal 52, and highly reflects the second light B2 and the fourth light B4, and highly transmits the third light B3.

[0099] DM54d is positioned on the optical paths of the second light B2 and the fourth light B4, which are highly reflected by DM54b, and highly reflects the fourth light B4 and highly transmits the second light B2. Damper 58b is positioned on the optical path of the second light B2, which is highly transmitted by DM54d, and absorbs the second light B2.

[0100] Lens 55c is positioned on the optical path of the third light B3, which has been highly transmitted through DM 54b, and focuses the third light B3 into the third CLBO crystal 53. The high-reflection mirror 56b is positioned downstream of lens 55c and highly reflects the third light B3. The half-wave plate 57 is positioned downstream of the high-reflection mirror 56b and rotates the polarization direction of the third light B3, which has been highly reflected by the high-reflection mirror 56b, by 90°.

[0101] Similar to the first embodiment, DM54c is an optical path converging element. In this embodiment, DM54c is positioned downstream of the half-wave plate 57 and transmits the third light B3, whose polarization direction has been rotated by 90°, with high transmittance so that it is incident on the third CLBO crystal 53. Additionally, DM54c is positioned on the optical path of the fourth light B4, which has been highly reflected by DM54d, and reflects the fourth light B4 with high transmittance so that it is incident on the third CLBO crystal 53.

[0102] The third CLBO crystal 53 generates and outputs fifth light B5, which is the sum frequency light of third light B3 and fourth light B4. DM54e is positioned downstream of the third CLBO crystal 53 and highly reflects fifth light B5 while highly transmitting third light B3 and fourth light B4. Damper 58c is positioned in the optical path of third light B3 and fourth light B4, which are highly transmitted through DM54e, and absorbs third light B3 and fourth light B4.

[0103] Furthermore, the relationship between reflection and transmission in DM54a to DM54e may be reversed from the relationship described above. In other words, the arrangement of the multiple components included in the wavelength conversion system 5b can be modified in various ways.

[0104] 3.2 Effects Similar to the wavelength conversion system 5a according to the first embodiment, the wavelength conversion system 5b according to this embodiment expands the optical path length, allowing for the arrangement of multiple nonlinear optical crystals from the viewpoint of improving the efficiency of wavelength conversion. This improves the degree of design freedom, allowing for the efficient arrangement of dichroic mirrors, dampers, and the like.

[0105] 4. Third Embodiment Next, a solid-state laser system 10 according to the third embodiment of this disclosure will be described. The solid-state laser system 10 according to the third embodiment differs from the solid-state laser system 10 according to the first embodiment only in the configuration of the wavelength conversion system.

[0106] 4.1 Structure and Operation The wavelength conversion system according to this embodiment is a modified version of the wavelength conversion system 5a according to the first embodiment, in which the half-wave plate 57 included in the polarization direction changing optical system 60 is replaced with the periscope optical system 80 shown in Figure 7. In Figure 7, the symbol D indicates the polarization direction of the third light B3. The X, Y, and Z directions are mutually orthogonal directions.

[0107] The periscope optical system 80 includes a first periscope mirror 81 and a second periscope mirror 82. The first periscope mirror 81 is positioned on the optical path of the third light B3 and deflects the optical path by 90° by highly reflecting the third light B3. The second periscope mirror 82 is positioned on the optical path of the third light B3 that has been highly reflected by the first periscope mirror 81 and deflects the optical path by 90° by highly reflecting the third light B3. The second periscope mirror 82 is positioned to reflect the third light B3 in a direction perpendicular to the direction in which the third light B3 is incident on the first periscope mirror 81.

[0108] The third light beam B3 travels in the X direction and is incident on the first periscope mirror 81, where it is highly reflected in the Z direction. At this time, the polarization direction D of the third light beam B3 is in the Y direction. The optical path of the third light beam B3 is changed due to the high reflection at the first periscope mirror 81, but the polarization direction D is not changed. The third light beam B3, highly reflected at the first periscope mirror 81, travels in the Z direction and is incident on the second periscope mirror 82, where it is highly reflected in the Y direction. Due to the high reflection at the second periscope mirror 82, the polarization direction D is rotated by 90°.

[0109] Thus, the periscope optical system 80, like the half-wave plate 57, makes it possible to rotate the polarization direction of the third light B3 by 90°. The periscope optical system 80 may also be configured using three or more periscope mirrors.

[0110] 4.2 Effects Since the half-wave plate 57 is a light-transmitting element, thermal load may affect the polarization direction. In contrast, the periscope optical system 80 is composed of periscope mirrors, which are light-reflecting elements, so thermal load is less likely to occur, and the effect of thermal load on the polarization direction can be suppressed.

[0111] In addition, a periscope optical system 80 may be used instead of the half-wave plate 57 included in the polarization direction changing optical system 60a of the wavelength conversion system 5b according to the second embodiment.

[0112] 5. Fourth Embodiment Next, a solid-state laser system 10 according to the fourth embodiment of this disclosure will be described. The solid-state laser system 10 according to the fourth embodiment differs from the solid-state laser system 10 according to the second embodiment only in the configuration of the wavelength conversion system. In the following, the same reference numerals are used for components that are the same as in the second embodiment, and their descriptions are omitted as appropriate.

[0113] 5.1 Structure and Operation The configuration and operation of the wavelength conversion system 5c according to the fourth embodiment will be explained using Figure 8. Figure 8 shows the configuration of the wavelength conversion system 5c according to the fourth embodiment. The wavelength conversion system 5c includes first to third CLBO crystals 51 to 53, DMs 54a, 54d, 54e, lenses 55a, 55b, high-reflection mirrors 56d, and dampers 58a to 58c.

[0114] In this embodiment, the first CLBO crystal 51 and the third CLBO crystal 53 are each nonlinear optical crystals having type-1 phase matching conditions. The second CLBO crystal 52 is a nonlinear optical crystal having type-2 phase matching conditions. The second CLBO crystal 52 is configured such that the angle between the optical axis and the optical path axis of the incident laser light is a phase matching angle that satisfies the type-2 phase matching conditions.

[0115] In this embodiment, since the second CLBO crystal 52 has a type-2 phase matching condition, the polarization directions of the second light B2 and the third light B3 incident on the second CLBO crystal 52 are made orthogonal. As a result, the polarization directions of the third light B3 and the fourth light B4 output from the second CLBO crystal 52 become parallel, so there is no need to provide a polarization direction changing optical system 60a as in the second embodiment.

[0116] Therefore, the wavelength conversion system 5c is not provided with a polarization direction changing optical system 60a. Downstream of the second CLBO crystal 52, a DM 54d is positioned to highly reflect the second light B2 and highly transmit the third light B3 and the fourth light B4. The third light B3 and the fourth light B4, which have been highly transmitted through the DM 54d, are incident on the third CLBO crystal 53 with their polarization directions parallel. The damper 58b is positioned in the optical path of the second light B2, which has been highly reflected by the DM 54d, and absorbs the second light B2.

[0117] DM54e is positioned downstream of the third CLBO crystal 53 and highly reflects the fifth light B5 while highly transmitting the third light B3 and the fourth light B4. The high-reflection mirror 56d is positioned in the optical path of the fifth light B5, which is highly reflected by DM54e, and highly reflects the fifth light B5.

[0118] In this embodiment, since lens 55c is not provided, lens 55b is configured to focus the third light B3 between the second CLBO crystal 52 and the third CLBO crystal 53.

[0119] The other components of the wavelength conversion system 5c are the same as those of the wavelength conversion system 5b. Note that the relationship between reflection and transmission of DM54a, 54d, and 54e may be reversed from the relationship described above. In other words, the arrangement of the multiple components included in the wavelength conversion system 5c can be varied in various ways. Furthermore, the high-reflection mirror 56d is not an essential component.

[0120] 5.2 Effects In this embodiment, the second CLBO crystal 52 is a nonlinear optical crystal having type-2 phase matching conditions, so it is not necessary to provide a half-wave plate 57 as in the second embodiment. This makes it possible to suppress the influence of thermal load on the polarization direction.

[0121] 6. Methods for Manufacturing Electronic Devices Figure 9 schematically shows an example configuration of the exposure apparatus 100. The exposure apparatus 100 includes an illumination optical system 104 and a projection optical system 106. The illumination optical system 104 illuminates the reticle pattern of a reticle (not shown) placed on a reticle stage RT with pulsed laser light PL incident from, for example, a solid-state laser system 10. The projection optical system 106 reduces and projects the pulsed laser light PL that has passed through the reticle onto a workpiece (not shown) placed on a workpiece table WT to form an image. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist.

[0122] The exposure apparatus 100 exposes the workpiece to a pulsed laser beam PL that reflects the reticle pattern by synchronously moving the reticle stage RT and the workpiece table WT in parallel. After transferring the reticle pattern to the semiconductor wafer through the exposure process described above, a semiconductor device can be manufactured by going through several processes. The semiconductor device is an example of an "electronic device" in this disclosure.

[0123] The above description is intended to be illustrative and not restrictive. It will therefore be apparent to those skilled in the art that modifications can be made to each embodiment of this disclosure without departing from the scope of the attached claims.

[0124] Terms used throughout this specification and the appended claims should be interpreted as “non-limiting” terms. For example, the terms “includes” or “contains” should be interpreted as “not limited to what is described as included.” The term “has” should be interpreted as “not limited to what is described as having.” Furthermore, the modifying phrase “one” as used throughout this specification and the appended claims should be interpreted as “at least one” or “one or more.” Also, the term “at least one of A, B, and C” should be interpreted as “A,” “B,” “C,” “A+B,” “A+C,” “B+C,” or “A+B+C,” and further, should be interpreted as including combinations of these with anything other than “A,” “B,” and “C.”

Claims

1. A first nonlinear optical crystal into which a first light having a first wavelength is incident and which outputs a second light having a second wavelength that is the second harmonic of the first light, A second nonlinear optical crystal is incident on the second light and a third light having a third wavelength, and outputs a fourth light having a fourth wavelength which is the sum frequency of the second light and the third light, and the third light. A third nonlinear optical crystal that receives the third and fourth light and outputs a fifth light having a fifth wavelength which is the sum frequency of the third and fourth light, A focusing optical system that incidents the first light onto the first nonlinear optical crystal such that the beam waist position of the second light is located within the second nonlinear optical crystal, Equipped with, The first nonlinear optical crystal is positioned within the range from the beam waist position of the second light to the Rayleigh length of the second light, The third nonlinear optical crystal is positioned within a range from the beam waist position of the second light to the Rayleigh length of the fourth light. Wavelength conversion system.

2. A wavelength conversion system according to claim 1, The numerical aperture of the aforementioned focusing optical system is NA １ , the second wavelength is λ ２ L is the distance from the beam waist position of the second light to the surface of the first nonlinear optical crystal into which the first light is incident. １ In this case, the following equation (1) is satisfied. [Math 1]

3. A wavelength conversion system according to claim 1, The first nonlinear optical crystal, the second nonlinear optical crystal, and the third nonlinear optical crystal have a type-1 phase matching condition. The second and third light incident on the second nonlinear optical crystal are linearly polarized and have parallel polarization directions. The system includes a polarization direction changing optical system that rotates the polarization direction of the third light incident on the third nonlinear optical crystal by 90°.

4. A wavelength conversion system according to claim 3, The polarization direction changing optical system includes a half-wave plate that rotates the polarization direction of the third light by 90°.

5. A wavelength conversion system according to claim 3, The polarization direction changing optical system includes a periscope optical system that rotates the polarization direction of the third light by 90°.

6. A wavelength conversion system according to claim 1, The first nonlinear optical crystal and the third nonlinear optical crystal each have a type-1 phase matching condition, The second nonlinear optical crystal has a type-2 phase matching condition, The second and third light incident on the second nonlinear optical crystal are linearly polarized and their polarization directions are orthogonal.

7. A wavelength conversion system according to claim 1, The first nonlinear optical crystal, the second nonlinear optical crystal, and the third nonlinear optical crystal are CLBO crystals.

8. A wavelength conversion system according to claim 1, The third wavelength is longer than the first wavelength, the first wavelength is longer than the second wavelength, the second wavelength is longer than the fourth wavelength, and the fourth wavelength is longer than the fifth wavelength.

9. A first nonlinear optical crystal into which a first light having a first wavelength is incident and which outputs a second light having a second wavelength that is the second harmonic of the first light, A second nonlinear optical crystal is incident on the second light and a third light having a third wavelength, and outputs a fourth light having a fourth wavelength which is the sum frequency of the second light and the third light, and the third light. A third nonlinear optical crystal that receives the third and fourth light and outputs a fifth light having a fifth wavelength which is the sum frequency of the third and fourth light, A focusing optical system that incidents the first light onto the first nonlinear optical crystal such that the beam waist position of the second light is located within the second nonlinear optical crystal, Equipped with, The first nonlinear optical crystal is positioned within the range from the beam waist position of the second light to the Rayleigh length of the second light, The third nonlinear optical crystal is positioned within a range from the beam waist position of the second light to the Rayleigh length of the fourth light. Wavelength conversion system, A signal laser device that outputs signal laser light, An amplification system that pulses the signal laser light based on the pump laser light and outputs the pulsed amplified signal laser light as the third light to the wavelength conversion system, A pump laser device that generates the pump laser light and the first light, outputs the pump laser light to the amplification system, and outputs the first light to the wavelength conversion system, A solid-state laser system equipped with [specific features / features].

10. A method for manufacturing electronic devices, A first nonlinear optical crystal into which a first light having a first wavelength is incident and which outputs a second light having a second wavelength that is the second harmonic of the first light, A second nonlinear optical crystal is incident on the second light and a third light having a third wavelength, and outputs a fourth light having a fourth wavelength which is the sum frequency of the second light and the third light, and the third light. A third nonlinear optical crystal that receives the third and fourth light and outputs a fifth light having a fifth wavelength which is the sum frequency of the third and fourth light, A focusing optical system that incidents the first light onto the first nonlinear optical crystal such that the beam waist position of the second light is located within the second nonlinear optical crystal, Equipped with, The first nonlinear optical crystal is positioned within the range from the beam waist position of the second light to the Rayleigh length of the second light, The third nonlinear optical crystal is positioned within a range from the beam waist position of the second light to the Rayleigh length of the fourth light. A solid-state laser system including a wavelength conversion system generates laser light, The laser light is output to the exposure apparatus, To manufacture an electronic device, the process involves exposing a photosensitive substrate to laser light within the exposure apparatus. A method for manufacturing electronic devices.

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