Extreme ultraviolet light generating apparatus and method for manufacturing electronic devices

Abstract

To provide a device for generating EUV light capable of efficiently generating EUV light.SOLUTION: A device for generating extreme-ultraviolet light comprises: a target supply unit ejecting a droplet target into a chamber device; a pre-pulse laser beam irradiation system irradiating the droplet target with a pre-pulse laser beam having linearly polarized light and generating a diffusion target; and a main pulse laser beam irradiation system irradiating the diffusion target with a main pulse laser beam, and generating extreme-ultraviolet light, wherein a cross section vertical to an optical axis of the main pulse laser beam when being emitted to the diffusion target is a shape long in the polarization direction of the pre-pulse laser beam rather than directions other than the polarization direction, when being emitted to the droplet target.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to an extreme ultraviolet light generating apparatus and a method for manufacturing an electronic device. [Background technology]

[0002] In recent years, with the miniaturization of semiconductor processes, the miniaturization of transfer patterns in optical lithography for semiconductor processes has progressed rapidly. In the next generation, fine processing of 10 nm or less will be required. For this reason, there is a demand for the development of semiconductor exposure equipment that combines a device for generating extreme ultraviolet (EUV) light with a wavelength of approximately 13 nm and a reduced projection reflective optical system.

[0003] As an EUV light generation device, development of a Laser Produced Plasma (LPP) type device that uses plasma generated by irradiating a target material with laser light is progressing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 9,130,345 [Patent Document 2] US Patent Application Publication No. 2013 / 0105712 [Patent Document 3] Summary of the specification of U.S. Patent No. 9,357,625

[0005] An extreme ultraviolet light generation apparatus according to one aspect of the present disclosure includes a target supply unit that discharges a droplet target into a chamber apparatus, a pre-pulse laser light irradiation system that irradiates the droplet target with linearly polarized pre-pulse laser light to generate a diffused target, and a main pulse laser light irradiation system that irradiates the diffused target with main pulse laser light to generate extreme ultraviolet light, wherein a cross section perpendicular to the optical axis of the main pulse laser light when irradiating the diffused target may have a shape that is longer in the polarization direction of the pre-pulse laser light when irradiating the droplet target than in any other direction.

[0006] Furthermore, a method for manufacturing an electronic device according to one aspect of the present disclosure may include: a target supply unit that discharges a droplet target into a chamber apparatus; a pre-pulse laser light irradiation system that irradiates the droplet target with linearly polarized pre-pulse laser light to generate a diffused target; and a main pulse laser light irradiation system that irradiates the diffused target with main pulse laser light to generate extreme ultraviolet light, wherein a cross section perpendicular to an optical axis of the main pulse laser light when irradiating the diffused target is longer in the polarization direction of the pre-pulse laser light when irradiating the droplet target than in any other direction; outputting the extreme ultraviolet light generated by the extreme ultraviolet light generation device to an exposure device; and exposing a photosensitive substrate in the exposure device to the extreme ultraviolet light to manufacture an electronic device.

[0007] Furthermore, a method for manufacturing an electronic device according to another aspect of the present disclosure may include: irradiating a mask with the extreme ultraviolet light generated by the extreme ultraviolet light generation device, the extreme ultraviolet light being longer in a polarization direction than in any other direction; selecting a mask using the inspection results; and exposing and transferring a pattern formed on the selected mask onto a photosensitive substrate. [Brief explanation of the drawings]

[0008] Some embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a schematic diagram showing an example of the overall configuration of an electronic device manufacturing apparatus. [Figure 2] FIG. 2 is a schematic diagram showing an example of the overall schematic configuration of an electronic device manufacturing apparatus different from the electronic device manufacturing apparatus shown in FIG. [Figure 3] FIG. 3 is a schematic diagram showing an example of the overall configuration of an extreme ultraviolet light generation apparatus of a comparative example. [Figure 4] FIG. 4 is a diagram showing an example of the relationship between a diffused target and a cross section of the main pulse laser beam when irradiating the diffused target. [Figure 5] FIG. 5 is a diagram showing another example of the relationship between the diffused target and the cross section of the main pulse laser beam. [Figure 6] FIG. 6 is a schematic diagram illustrating an example of the overall configuration of the extreme ultraviolet light generation apparatus according to the first embodiment. [Figure 7] FIG. 7 is a partial cross-sectional view showing an example of the schematic configuration of the shaping unit. [Figure 8]FIG. 8 is a diagram illustrating an example of the relationship between the diffused target and the cross section of the main pulse laser beam in the first embodiment. [Figure 9] FIG. 9 is a schematic diagram illustrating an example of the overall configuration of an extreme ultraviolet light generation apparatus according to the second embodiment. [Figure 10] FIG. 10 is a diagram showing the position of the EUV collector mirror relative to the optical axis of the pre-pulse laser beam when generating a diffused target, viewed from the Y direction. [Figure 11] FIG. 11 is a diagram of the diffused target generated by the pre-pulse laser beam as viewed from the Y direction. [Figure 12] FIG. 12 is a view of the diffused target shown in FIG. 11 as viewed from the Z direction. [Figure 13] FIG. 13 is a schematic diagram illustrating an example of the overall configuration of an extreme ultraviolet light generation apparatus according to the third embodiment. [Figure 14] FIG. 14 is a diagram of a diffused target irradiated with a main pulse laser beam polarized in the Y direction, viewed from the Y direction. [Figure 15] FIG. 15 is a view of the diffused target shown in FIG. 14 as viewed from the Z direction. Embodiment

[0009] 1. Overview 2. Description of electronic device manufacturing equipment 3. Description of the extreme ultraviolet light generation device as a comparative example 3.1 Configuration 3.2 Operation 3.3 Challenges 4. Description of the extreme ultraviolet light generation device according to the first embodiment 4.1 Configuration 4.2 Operation 4.3 Actions and Effects 5. Description of the extreme ultraviolet light generation device according to the second embodiment 5.1 Configuration 5.2 Actions and Effects 6. Description of the extreme ultraviolet light generation device according to the third embodiment 6.1 Configuration 6.2 Actions and Effects

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below are examples of the present disclosure and are not intended to limit the scope of the present disclosure. Furthermore, not all of the configurations and operations described in each embodiment are necessarily essential to the configurations and operations of the present disclosure. Identical components are designated by the same reference numerals, and redundant descriptions will be omitted.

[0011] 1. Overview An embodiment of the present disclosure relates to an extreme ultraviolet light generation apparatus that generates light with a wavelength called extreme ultraviolet (EUV), and an electronic device manufacturing apparatus. Note that hereinafter, extreme ultraviolet light may also be referred to as EUV light.

[0012] 2. Description of electronic device manufacturing equipment FIG. 1 is a schematic diagram showing an example of the overall configuration of an electronic device manufacturing apparatus. The electronic device manufacturing apparatus shown in FIG. 1 includes an EUV light generation system 100 and an exposure apparatus 200. The exposure apparatus 200 includes a mask irradiation unit 210 including multiple mirrors 211 and 212, which are reflective optical systems, and a workpiece irradiation unit 220 including multiple mirrors 221 and 222, which are reflective optical systems separate from the reflective optical system of the mask irradiation unit 210. The mask irradiation unit 210 illuminates a mask pattern on a mask table MT via the mirrors 211 and 212 with EUV light 101 incident from the EUV light generation system 100. The workpiece irradiation unit 220 forms an image of the EUV light 101 reflected by the mask table MT onto a workpiece (not shown) placed on a workpiece table WT via the mirrors 221 and 222. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist. Exposure apparatus 200 synchronously translates mask table MT and workpiece table WT to expose the workpiece to EUV light 101 that reflects the mask pattern. By using the exposure process described above, a device pattern can be transferred onto a semiconductor wafer, thereby manufacturing a semiconductor device.

[0013] FIG. 2 is a schematic diagram illustrating an example of the overall configuration of an electronic device manufacturing apparatus different from the electronic device manufacturing apparatus illustrated in FIG. 1. The electronic device manufacturing apparatus illustrated in FIG. 2 includes an EUV light generation apparatus 100 and an inspection apparatus 300. The inspection apparatus 300 includes an illumination optical system 310 including multiple mirrors 311, 313, and 315, which are reflective optical systems, and a detection optical system 320 including multiple mirrors 321 and 323, which are reflective optical systems separate from the reflective optical system of the illumination optical system 310, and a detector 325. The illumination optical system 310 reflects the EUV light 101 incident from the EUV light generation apparatus 100 by the mirrors 311, 313, and 315, and irradiates the mask 333 placed on a mask stage 331. The mask 333 includes a mask blank before a pattern is formed. The detection optical system 320 reflects the EUV light 101, which reflects the pattern from the mask 333, by the mirrors 321 and 323, and forms an image on the light-receiving surface of the detector 325. The detector 325 receives the EUV light 101 and acquires an image of the mask 333. The detector 325 is, for example, a TDI (Time Delay Integration) camera. The image of the mask 333 acquired through the above process is used to inspect the mask 333 for defects, and the inspection results are used to select a mask suitable for manufacturing an electronic device. Then, the pattern formed on the selected mask is exposed and transferred onto a photosensitive substrate using the exposure apparatus 200, thereby manufacturing an electronic device.

[0014] 3. Description of the extreme ultraviolet light generation device as a comparative example 3.1 Configuration A comparative example of an EUV light generation system 100 will be described. Note that the comparative example of the present disclosure refers to a configuration that the applicant recognizes as being known only by the applicant, and is not a publicly known example that the applicant acknowledges. In the following, the EUV light generation system 100 that emits EUV light 101 toward an exposure system 200 as an external device, as shown in FIG. 1, will be used for the description. Note that the same functions and effects can be obtained with an EUV light generation system 100 that emits EUV light 101 toward an inspection system 300 as an external device, as shown in FIG. 2.

[0015] 3 is a schematic diagram showing an example of the overall configuration of the EUV light generation system 100 of this embodiment. As shown in Fig. 3, the EUV light generation system 100 mainly includes a chamber apparatus 10, a main pulse laser beam irradiation system MPS including a main pulse laser apparatus 130, a pre-pulse laser beam irradiation system PPS including a pre-pulse laser apparatus 140, and a control system 120.

[0016] The chamber apparatus 10 is a sealable container. The chamber apparatus 10 includes an inner wall 10b that encloses an internal space of a low-pressure atmosphere. The chamber apparatus 10 also includes a sub-chamber 15. A target supply unit 40 is attached to the sub-chamber 15 so as to penetrate the wall of the sub-chamber 15. The target supply unit 40 includes a tank 41, a nozzle 42, and a pressure regulator 43, and supplies a droplet target DL to the internal space of the chamber apparatus 10. The droplet target DL may also be referred to simply as a droplet or a target.

[0017] The tank 41 stores a target material that will become the droplet targets DL. The target material contains tin. The interior of the tank 41 is in communication with a pressure regulator 43 that adjusts the pressure inside the tank 41. A heater 44 and a temperature sensor 45 are attached to the tank 41. The heater 44 heats the tank 41 with current supplied from a heater power supply 46. This heating melts the target material in the tank 41. The temperature sensor 45 measures the temperature of the target material in the tank 41 via the tank 41. The pressure regulator 43, the temperature sensor 45, and the heater power supply 46 are electrically connected to a processor 121 included in the control system 120.

[0018] The nozzle 42 is attached to the tank 41 and discharges the target material. A piezoelectric element 47 is attached to the nozzle 42. The piezoelectric element 47 is electrically connected to a piezoelectric power supply 48 and is driven by a voltage applied from the piezoelectric power supply 48. The piezoelectric power supply 48 is electrically connected to the processor 121. By operation of the piezoelectric element 47, the target material discharged from the nozzle 42 is turned into a droplet target DL.

[0019] The chamber apparatus 10 includes a target collection unit 14. The target collection unit 14 is a box attached to an inner wall 10b of the chamber apparatus 10, and is in communication with the internal space of the chamber apparatus 10 via an opening 10a provided in the inner wall 10b of the chamber apparatus 10. The opening 10a is provided directly below the nozzle 42, and the target collection unit 14 is a drain tank that collects unwanted droplet targets DL that pass through the opening 10a and reach the target collection unit 14.

[0020] At least one through-hole is provided in the inner wall 10b of the chamber device 10. This through-hole is covered by a window 12, through which pulsed laser beams emitted from the main pulse laser device 130 and the pre-pulse laser device 140 pass.

[0021] A laser focusing optical system 13 is also disposed within the interior space of the chamber apparatus 10. The laser focusing optical system 13 includes a laser focusing mirror 13A and a high-reflection mirror 13B. The laser focusing mirror 13A reflects and focuses the laser light passing through the window 12. The high-reflection mirror 13B reflects the light focused by the laser focusing mirror 13A. The positions of the laser focusing mirror 13A and the high-reflection mirror 13B are adjusted by a laser beam manipulator 13C so that the focusing position of the laser light within the interior space of the chamber apparatus 10 is a position specified by the processor 121. The focusing position is adjusted to be directly below the nozzle 42. When the laser light irradiates the target material at the focusing position, plasma is generated by the irradiation, and EUV light 101 is emitted from the plasma. The region where the plasma is generated is sometimes referred to as a plasma generation region AR.

[0022] An EUV light collector mirror 75 including, for example, a spheroid-shaped reflecting surface 75a is disposed in the internal space of the chamber apparatus 10. The reflecting surface 75a reflects EUV light 101 emitted from the plasma in the plasma generation region AR. The reflecting surface 75a has a first focal point and a second focal point. The reflecting surface 75a may be disposed, for example, so that the first focal point is located in the plasma generation region AR and the second focal point is located at an intermediate focus point IF. In FIG. 3 , a line passing through the first and second focal points is indicated as a focal line L0. In the following description, the direction in which the focal line L0 extends may be referred to as the Z direction, the ejection direction of the droplet target DL and perpendicular to the Z direction as the Y direction, and the direction perpendicular to the Z and Y directions as the X direction.

[0023] The EUV light generation system 100 also includes a connection part 19 that connects the internal space of the chamber apparatus 10 with the internal space of the exposure system 200. A wall having an aperture formed therein is disposed inside the connection part 19. This wall is preferably disposed so that the aperture is located at the second focal point. The connection part 19 is an exit port for the EUV light 101 in the EUV light generation system 100, and the EUV light 101 is emitted from the connection part 19 and enters the exposure system 200.

[0024] The EUV light generation system 100 also includes a pressure sensor 26 and a target sensor 27. The pressure sensor 26 and the target sensor 27 are attached to the chamber apparatus 10 and electrically connected to the processor 121. The pressure sensor 26 measures the pressure in the internal space of the chamber apparatus 10 and outputs a signal indicating this pressure to the processor 121. The target sensor 27 includes, for example, an imaging function and detects the presence, trajectory, position, flow velocity, etc. of the droplet target DL ejected from the nozzle hole of the nozzle 42 in response to instructions from the processor 121. The target sensor 27 may be disposed inside the chamber apparatus 10 or may be disposed outside the chamber apparatus 10 and detect the droplet target DL through a window (not shown) provided in the wall of the chamber apparatus 10. The target sensor 27 includes a light-receiving optical system (not shown) and an imaging unit (not shown), such as a charge-coupled device (CCD) or a photodiode. The light-receiving optical system forms an image of the trajectory of the droplet target DL and its surroundings on the light-receiving surface of the imaging unit to improve the detection accuracy of the droplet target DL. When the droplet target DL passes through a light collection area of ​​a light source (not shown) that is arranged to improve contrast within the field of view of the target sensor 27, the imaging unit detects the trajectory of the droplet target DL and changes in the light passing around it. The imaging unit converts the detected changes in light into an electrical signal that serves as image data for the droplet target DL. The imaging unit outputs this electrical signal to the processor 121.

[0025] The main pulse laser device 130 is, for example, a YAG laser device or a CO2 laser device, includes a master oscillator that performs burst operation, and emits main pulse laser light MPL. Note that burst operation is an operation in which continuous main pulse laser light MPL is emitted at a predetermined repetition rate during burst on, and emission of the main pulse laser light MPL is suppressed during burst off.

[0026] The pre-pulse laser device 140 emits a pre-pulse laser beam PPL having linearly polarized light polarized in a predetermined direction. In the example of FIG. 3 , the wavelength of the pre-pulse laser beam PPL is different from the wavelength of the main pulse laser beam MPL. Therefore, for example, if the main pulse laser device 130 is a YAG laser device, the pre-pulse laser device 140 is, for example, a CO laser device. Note that the pre-pulse laser beam PPL and the main pulse laser beam MPL may have the same wavelength. In this case, the main pulse laser device 130 and the pre-pulse laser device 140 are, for example, both YAG laser devices or both CO laser devices. The pre-pulse laser device 140 is configured to emit the pre-pulse laser beam PPL at a timing different from the timing at which the main pulse laser beam MPL is emitted from the main pulse laser device 130. This control is performed by a control system 120, which will be described later.

[0027] The propagation directions of the main pulse laser beam MPL and the pre-pulse laser beam PPL are adjusted by a laser beam delivery optical system having a plurality of mirrors. The laser beam delivery optical system that adjusts the propagation direction of the main pulse laser beam MPL includes mirrors 31 and 32. The laser beam delivery optical system that adjusts the propagation direction of the pre-pulse laser beam PPL includes a mirror 33 and an optical path combining member 34. The optical path combining member 34 is disposed at a position where the optical paths of the pre-pulse laser beam PPL and the main pulse laser beam MPL intersect. In this example, the optical path combining member 34 disposed in this manner is a dichroic mirror that reflects the pre-pulse laser beam PPL and transmits the main pulse laser beam MPL, thereby causing the optical paths of the main pulse laser beam MPL and the pre-pulse laser beam PPL to roughly overlap each other. The orientation of at least one of these mirrors 31, 32, and 33 and the optical path combining member 34 is adjusted by an actuator (not shown), and this adjustment allows the main pulse laser beam MPL and the pre-pulse laser beam PPL to be appropriately propagated from the window 12 into the internal space of the chamber apparatus 10. Note that if the pre-pulse laser beam PPL and the main pulse laser beam MPL have the same wavelength but have polarization directions that differ by 90°, the optical path combining member 34 may be a polarizer.

[0028] The main pulse laser beam irradiation system MPS is a system that irradiates a target material with a main pulse laser beam MPL. Therefore, in this example, the main pulse laser beam irradiation system MPS includes, in addition to the main pulse laser device 130, mirrors 31 and 32, a beam path combining member 34, and a laser focusing optical system 13. Furthermore, the pre-pulse laser beam irradiation system PPS is a system that irradiates a target material with a pre-pulse laser beam PPL. Therefore, in this example, the pre-pulse laser beam irradiation system PPS includes, in addition to the pre-pulse laser device 140, a mirror 33, a beam path combining member 34, and a laser focusing optical system 13.

[0029] The processor 121 of the control system 120 of the present disclosure is a processing device including a storage device storing a control program and a CPU (Central Processing Unit) that executes the control program. The processor 121 is specially configured or programmed to execute various processes described herein and controls the entire EUV light generation apparatus 100. The processor 121 receives inputs such as a signal related to the pressure in the internal space of the chamber apparatus 10 measured by the pressure sensor 26, a signal related to image data of the droplet target DL captured by the target sensor 27, and a burst signal instructing a burst operation from the exposure apparatus 200. The processor 121 processes the various signals and may control, for example, the timing at which the droplet target DL is discharged and the discharge direction of the droplet target DL. The processor 121 may also control the emission timing of the main pulse laser device 130 and the pre-pulse laser device 140, the propagation direction and focus position of the main pulse laser beam MPL and the pre-pulse laser beam PPL, and the like. The various controls described above are merely examples, and other controls may be added as necessary, as described below.

[0030] The processor 121 in this example is electrically connected to the main pulse laser device 130 and the pre-pulse laser device 140 via a delay circuit 122 of the control system 120. The delay circuit 122 slightly changes the trigger signals of the main pulse laser device 130 and the pre-pulse laser device 140 output from the processor 121. Specifically, the delay circuit 122 generates a delay in the trigger signals input to the main pulse laser device 130 and the pre-pulse laser device 140 so that the irradiation timing of the main pulse laser device 130 is delayed relative to the irradiation timing of the pre-pulse laser device 140.

[0031] The chamber apparatus 10 is provided with a central gas supply unit 81 that supplies an etching gas to the internal space of the chamber apparatus 10. As described above, since the target material contains tin, the etching gas is, for example, a hydrogen-containing gas in which the hydrogen gas concentration is considered to be 100%. Alternatively, the etching gas may be a balance gas in which the hydrogen gas concentration is, for example, approximately 3%. The balance gas may include nitrogen (N2) gas or argon (Ar) gas. Incidentally, when the target material constituting the droplet target DL is irradiated with the main pulse laser beam MPL in the plasma generation region AR and converted into plasma, tin microparticles and charged tin particles are generated. The tin constituting these microparticles and charged particles reacts with hydrogen contained in the etching gas supplied to the internal space of the chamber apparatus 10. When tin reacts with hydrogen, it becomes stannane (SnH4), a gas at room temperature.

[0032] The center-side gas supply unit 81 has a side surface shaped like a truncated cone and passes through a through-hole 75c formed in the center of the EUV light collector mirror 75. The center-side gas supply unit 81 is sometimes called a cone. The center-side gas supply unit 81 also includes a center-side gas supply port 81a, which is a nozzle. The center-side gas supply port 81a is located on a focal line L0 that passes through the first and second focal points of the reflecting surface 75a. The focal line L0 is aligned with the central axis direction of the reflecting surface 75a. The center-side gas supply port 81a supplies an etching gas from the center of the reflecting surface 75a toward the plasma generation region AR. The etching gas is preferably supplied from the center-side gas supply port 81a along the focal line L0, in a direction away from the center of the reflecting surface 75a. The center-side gas supply port 81a is connected to a gas supply device (not shown), which is a tank, via a piping (not shown) of the center-side gas supply unit 81, and the etching gas is supplied from the gas supply device. The operation of the gas supply device is controlled by the processor 121. A supply gas flow rate regulator (not shown), which is a valve, may be disposed in the piping (not shown).

[0033] The center-side gas supply port 81a is a gas supply port that supplies an etching gas into the internal space of the chamber apparatus 10, and also serves as an emission port through which the pre-pulse laser beam PPL and the main pulse laser beam MPL are emitted into the internal space of the chamber apparatus 10. The pre-pulse laser beam PPL and the main pulse laser beam MPL pass through the window 12 and the center-side gas supply port 81a and proceed toward the internal space of the chamber apparatus 10.

[0034] An exhaust port 10E is provided on the inner wall 10b of the chamber apparatus 10. Since the exposure device 200 is disposed on the focal line L0, the exhaust port 10E is provided on the inner wall 10b on the side of the focal line L0. The direction along the central axis of the exhaust port 10E is, for example, perpendicular to the focal line L0. Furthermore, when viewed from a direction perpendicular to the focal line L0, the exhaust port 10E is provided on the opposite side of the reflecting surface 75a with respect to the plasma generation region AR. The exhaust port 10E exhausts gas from the internal space of the chamber apparatus 10. The exhaust port 10E is connected to an exhaust pipe 10P, which is connected to an exhaust pump 60.

[0035] When the target material is converted into plasma in the plasma generation region AR as described above, residual gas is generated in the internal space of the chamber apparatus 10 as exhaust gas. The residual gas contains tin particles and charged particles generated by the conversion of the target material into plasma, stannane formed when these particles react with the etching gas, and unreacted etching gas. Note that some of the charged particles are neutralized in the internal space of the chamber apparatus 10, and these neutralized charged particles are also included in the residual gas. The residual gas is sucked into the exhaust pump 60 via the exhaust port 10E and the exhaust pipe 10P.

[0036] 3.2 Operation Next, the operation of the EUV light generation system 100 of the comparative example will be described.

[0037] In the EUV light generation system 100, the atmosphere in the internal space of the chamber apparatus 10 is exhausted, for example, when the system is newly installed or during maintenance. At this time, the internal space of the chamber apparatus 10 may be repeatedly purged and exhausted to exhaust atmospheric components. An inert gas such as nitrogen or argon is preferably used as the purge gas. When the pressure in the internal space of the chamber apparatus 10 subsequently drops below a predetermined pressure, the processor 121 starts introducing an etching gas from the gas supply device into the internal space of the chamber apparatus 10 via the central gas supply unit 81. At this time, the processor 121 may control a supply gas flow rate regulator and an exhaust pump 60 (not shown) to maintain the pressure in the internal space of the chamber apparatus 10 at the predetermined pressure. The processor 121 then waits until a predetermined time has elapsed since the start of the introduction of the etching gas.

[0038] In addition, the processor 121 causes the exhaust pump 60 to exhaust the gas in the internal space of the chamber apparatus 10 through the exhaust port 10E, and maintains the pressure in the internal space of the chamber apparatus 10 at an approximately constant level based on a signal indicating the pressure in the internal space of the chamber apparatus 10 measured by the pressure sensor 26.

[0039] The processor 121 also supplies current from the heater power supply 46 to the heater 44 to heat and maintain the target material in the tank 41 at a predetermined temperature equal to or higher than the melting point, thereby raising the temperature of the heater 44. Based on the output of the temperature sensor 45, the processor 121 adjusts the value of the current supplied from the heater power supply 46 to the heater 44 to control the temperature of the target material to the predetermined temperature. When the target material is tin, the predetermined temperature is equal to or higher than the melting point of tin, 231.93°C, for example, between 240°C and 290°C. This completes preparations for discharging the droplet target DL.

[0040] Once preparation is complete, the processor 121 controls the pressure regulator 43 to supply inert gas from a gas supply source (not shown) into the tank 41 and adjust the pressure within the tank 41 so that the molten target material is discharged from the nozzle hole of the nozzle 42 at a predetermined flow rate. Under this pressure, the target material is discharged from the nozzle hole of the nozzle 42 into the chamber apparatus 10. The target material discharged from the nozzle hole may take the form of a jet. To generate the droplet target DL, the processor 121 controls the piezoelectric power supply 48 to apply a voltage of a predetermined waveform to the piezoelectric element 47. The piezoelectric power supply 48 applies the voltage so that the voltage waveform is, for example, sinusoidal, rectangular, or sawtooth. The vibration of the piezoelectric element 47 can propagate through the nozzle 42 to the target material being discharged from the nozzle hole of the nozzle 42. The target material is divided by this vibration at a predetermined period, becoming the droplet target DL. The diameter of the droplet target DL is approximately 20 μm or less.

[0041] When the droplet target DL is discharged, the target sensor 27 detects the timing at which the droplet target DL passes through a predetermined position in the internal space of the chamber apparatus 10. The processor 121 controls the timing at which the pre-pulse laser beam PPL is emitted from the pre-pulse laser device 140 based on a signal from the target sensor 27 so that the droplet target DL is irradiated with the pre-pulse laser beam PPL, and outputs a trigger signal. The trigger signal output from the processor 121 is input to the pre-pulse laser device 140 and the main pulse laser device 130 via a delay circuit 122. However, the delay circuit 122 inputs the trigger signal to the pre-pulse laser device 140 before inputting it to the main pulse laser device 130. When the trigger signal is input, the pre-pulse laser device 140 emits the pre-pulse laser beam PPL. The main pulse laser beam MPL is not emitted at the timing at which the pre-pulse laser beam PPL is emitted.

[0042] The pre-pulse laser light PPL is a picosecond pulse laser light having a temporal pulse width of, for example, 10 ps or more and 100 ps or less, or a nanosecond pulse laser light having a pulse width of, for example, 10 ns or more and 300 ns or less. The pulse width refers to the interval between the times when the intensity of the laser light is half of its maximum value, before and after the intensity reaches its maximum value. The picosecond pulse laser light and the nanosecond pulse laser light have roughly the same energy per pulse. Therefore, the picosecond pulse laser light has a higher energy density than the nanosecond pulse laser light. The fluence of the pre-pulse laser light PPL is, for example, 0.1 J / cm. 2 More than 100J / cm 2 Preferably, the fluence is 1 J / cm for picosecond pulsed laser light. 2 More than 20J / cm 2 or less than 1 J / cm for nanosecond pulsed laser light. 2 More than 3J / cm 2 The pre-pulse laser beam PPL emitted from the pre-pulse laser device 140 and having linear polarization is reflected by the mirror 33 and the optical path combining member 34 and irradiated onto the droplet target DL via the laser focusing optical system 13. At this time, the processor 121 controls the laser beam manipulator 13C of the laser focusing optical system 13 so that the pre-pulse laser beam PPL is focused near the plasma generation region AR. The droplet target DL irradiated with the pre-pulse laser beam PPL is diffused by laser ablation due to the energy of the laser beam, becoming a diffused target. Therefore, the pre-pulse laser beam irradiation system PPS is a system that irradiates the droplet target DL with the pre-pulse laser beam PPL to generate a diffused target.

[0043] The diffused target is a target in which the droplet target DL has been diffused, and therefore has a larger diameter and a lower density of the target material than the droplet target DL.

[0044] When a trigger signal is input to the main pulse laser device 130 with a delay from the timing at which a trigger signal is input to the pre-pulse laser device 140, the main pulse laser device 130 emits the main pulse laser beam MPL. The time difference between the timing at which the pre-pulse laser beam PPL is emitted and the timing at which the main pulse laser beam MPL is emitted is, for example, 50 ns or more and 500 ns or less in the case of a picosecond pulse laser beam, and 50 ns or more and 150 ns or less in the case of a nanosecond pulse laser beam. The processor 121 and the delay circuit 122 control the timing at which the main pulse laser beam MPL is emitted from the main pulse laser device 130 and output a light emission trigger signal so that the diffused target is irradiated with the main pulse laser beam MPL.

[0045] The main pulse laser beam MPL has a pulse width of, for example, 1 ns or more and 50 ns or less, more preferably 15 ns or more and 20 ns or less. The main pulse laser beam MPL emitted from the main pulse laser device 130 is reflected by mirrors 31 and 32, transmitted through the beam path combining member 34, and irradiated onto the diffused target in the plasma generation region AR via the laser focusing optical system 13. At this time, the processor 121 controls the laser beam manipulator 13C of the laser focusing optical system 13 so that the main pulse laser beam MPL is focused onto the plasma generation region AR. The diffused target irradiated with the main pulse laser beam MPL becomes plasma due to the energy of the laser beam, and light including EUV light is emitted from this plasma. Therefore, the main pulse laser beam irradiation system MPS is a system that generates EUV light by irradiating a diffused target with the main pulse laser beam MPL.

[0046] By irradiating the main pulse laser beam MPL onto a diffused target in which the density of the target material has been reduced in this manner, more of the target material is converted into plasma, and EUV light can be emitted more efficiently than when the main pulse laser beam MPL is irradiated directly onto the droplet target DL.

[0047] Of the light including EUV light generated in the plasma generation region AR, EUV light 101 is collected at an intermediate focus point IF by the EUV light collecting mirror 75 and then enters the exposure device 200 from the connection part 19 .

[0048] When the target material is converted into plasma, tin particles are generated as described above. These particles diffuse into the internal space of the chamber apparatus 10. The particles diffusing into the internal space of the chamber apparatus 10 react with the etching gas containing hydrogen supplied from the central gas supply unit 81 to become stannane. Most of the stannane obtained by the reaction with the etching gas flows into the exhaust port 10E along with the flow of unreacted etching gas. At least a portion of the unreacted charged particles, particles, and etching gas also flow into the exhaust port 10E.

[0049] The unreacted etching gas, fine particles, charged particles, stannane, etc. that have flowed into the exhaust port 10E flow as residual gases from the exhaust pipe 10P into the exhaust pump 60, where they are subjected to a predetermined exhaust process such as being made harmless.

[0050] 3.3 Challenges In the comparative EUV light generation system 100, the pre-pulse laser apparatus 140 emits a linearly polarized pre-pulse laser beam PPL. When a droplet target DL is irradiated with the linearly polarized pre-pulse laser beam PPL, the diffused target tends to spread into a shape that is longer in the polarization direction of the pre-pulse laser beam PPL than in other directions. The cross section perpendicular to the optical axis of the main pulse laser beam MPL is generally circular. FIG. 4 is a diagram showing an example of the relationship between the diffused target DT and the cross section of the main pulse laser beam MPL when irradiating the diffused target DT. FIG. 5 is a diagram showing another example of the relationship between the diffused target DT and the cross section of the main pulse laser beam MPL when irradiating the diffused target DT. In FIGS. 4 and 5, the diffused target DT is indicated by a dashed line for ease of viewing. As shown in FIG. 4, when the diameter of the cross section of the main pulse laser beam MPL is shorter than the longitudinal length of the cross section of the diffused target DT, the main pulse laser beam MPL is not irradiated onto a portion of the diffused target DT. Therefore, some of the target material is difficult to convert into plasma, and the unreacted target material that is not converted into plasma is exhausted from the exhaust pipe 10P or becomes debris and adheres to the inner wall 10b of the chamber apparatus 10 or the reflecting surface 75a of the EUV light collector mirror 75. Conversely, as shown in FIG. 5 , when the diameter of the cross section of the main pulse laser beam MPL is longer than the length of the cross section of the diffused target DT in the longitudinal direction, the cross section of the main pulse laser beam MPL becomes larger than the diffused target DT. Therefore, part of the main pulse laser beam MPL is not irradiated onto the diffused target DT, resulting in a loss of the main pulse laser beam MPL. For this reason, there is a demand for efficient generation of EUV light.

[0051] Therefore, in the following embodiment, an EUV light generation apparatus capable of efficiently generating EUV light will be exemplified.

[0052] 4. Description of the extreme ultraviolet light generation device according to the first embodiment Next, a description will be given of the configuration of the EUV light generation system 100 of embodiment 1. Note that the same components as those described above are denoted by the same reference numerals, and redundant description will be omitted unless otherwise specified.

[0053] 4.1 Configuration 6 is a schematic diagram showing an example of the overall configuration of an EUV light generation system 100 according to this embodiment. The EUV light generation system 100 according to this embodiment differs from the main pulse laser beam irradiation system MPS of the comparative example in that the main pulse laser beam irradiation system MPS includes a shaping unit 150.

[0054] The shaping unit 150 is disposed upstream of the optical path combining member 34 in the traveling direction of the main pulse laser beam MPL. In FIG. 6, an example in which the shaping unit 150 is disposed between the mirror 31 and the mirror 32 is shown.

[0055] Fig. 7 is a partial cross-sectional view showing a schematic configuration example of the shaping unit 150. Specifically, Fig. 7 is a partial cross-sectional view of the shaping unit 150 taken along a plane including the optical axis of the main pulse laser beam MPL. The shaping unit 150 includes a base 151, a rotary stage 153, actuators 155a and 155b, a housing 157, a cylindrical concave lens 159a, a cylindrical convex lens 159b, holders 161a and 161b, a base member 163, and a stage 165. In Fig. 7, the rotary stage 153 and the housing 157 are shown in cross section.

[0056] An opening 157a serving as an entrance port for the main pulse laser beam MPL and an opening 157b serving as an exit port for the main pulse laser beam MPL are provided on a side wall of the housing 157. A base member 163 is disposed on the bottom wall of the housing 157, and a holder 161a for holding the cylindrical concave lens 159a and a stage 165 are disposed on the base member 163. A holder 161b for holding the cylindrical convex lens 159b is disposed on the stage 165.

[0057] The concave surface of the cylindrical concave lens 159a faces the opening 157a, and the cylindrical convex lens 159b is located between the cylindrical concave lens 159a and the opening 157b. The convex surface of the cylindrical convex lens 159b faces the opening 157b, and the flat surface of the cylindrical convex lens 159b opposite the convex surface faces the flat surface of the cylindrical concave lens 159a opposite the concave surface. When the main pulse laser beam MPL passes through the cylindrical concave lens 159a, the cross section perpendicular to the optical axis of the main pulse laser beam MPL expands in a predetermined direction. When this main pulse laser beam MPL passes through the cylindrical convex lens 159b, the main pulse laser beam MPL expanding in the predetermined direction is collimated.

[0058] The actuator 155b is attached to the outer wall of the housing 157, the shaft of the actuator 155b extends along the optical axis of the main pulse laser beam MPL, and the tip of the shaft of the actuator 155b is connected to the side surface of the stage 165. The actuator 155b is also electrically connected to the processor 121, and moves the shaft along the optical axis of the main pulse laser beam MPL in response to a control signal from the processor 121, thereby pushing or pulling the stage 165. This moves the cylindrical convex lens 159b, and the distance between the cylindrical concave lens 159a and the cylindrical convex lens 159b is adjusted.

[0059] By adjusting the distance, the shaping unit 150 shapes the cross section perpendicular to the optical axis of the main pulse laser beam MPL when irradiating the diffused target DT into a shape that is longer in the polarization direction of the pre-pulse laser beam PPL than in any other direction, thereby adjusting the length of the cross section in the polarization direction. Such a cross section of the main pulse laser beam MPL has an elliptical shape that is longer in the polarization direction. This cross section is a cross section in a region where the intensity of the main pulse laser beam MPL is equal to or greater than half of the maximum intensity in the intensity distribution on the cross section of the main pulse laser beam MPL.

[0060] The rotation stage 153 and the actuator 155a are disposed on the base 151. The rotation stage 153 is cylindrical, and a housing 157 is supported inside the rotation stage 153. The actuator 155a is connected to the rotation stage 153 and is electrically connected to the processor 121, and rotates the rotation stage 153 around the optical axis of the main pulse laser beam MPL passing through the housing 157 in response to a control signal from the processor 121. This causes the cylindrical concave lens 159a and the cylindrical convex lens 159b inside the housing 157 to rotate, and the cross section perpendicular to the optical axis of the main pulse laser beam MPL when it is irradiated onto the diffused target DT also rotates in the direction around the optical axis.

[0061] Note that the holder 161a may be arranged on the stage 165 instead of the holder 161b. Alternatively, the holders 161a and 161b may be arranged on separate stages 165, and the actuator 155b may be connected to each stage 165. The actuator 155b may then move at least one of the cylindrical concave lens 159a and the cylindrical convex lens 159b along the optical axis of the main pulse laser beam MPL to adjust the distance between the cylindrical concave lens 159a and the cylindrical convex lens 159b.

[0062] 4.2 Operation Next, the operation of the EUV light generation system 100 according to this embodiment will be described.

[0063] As in the comparative example, when a droplet target DL is discharged from the target supply unit 40, the pre-pulse laser device 140 emits a linearly polarized pre-pulse laser beam PPL. When the droplet target DL is irradiated with the pre-pulse laser beam PPL, a diffused target DT is generated. The diffused target DT tends to expand into a shape that is longer in the polarization direction of the pre-pulse laser beam PPL than in any other direction due to the linearly polarized pre-pulse laser beam PPL when irradiating the droplet target DL. In the arrangement shown in FIG. 8 described below, the XZ plane is used as the incident plane of the linearly polarized pre-pulse laser beam PPL. Furthermore, when the pre-pulse laser beam PPL is S-polarized when irradiating the droplet target DL, the polarization direction of the pre-pulse laser beam PPL is the Y direction. Furthermore, when the pre-pulse laser beam PPL is P-polarized when irradiating the droplet target DL, the polarization direction of the pre-pulse laser beam PPL is the X direction.

[0064] Fig. 8 is a diagram showing an example of the relationship between the diffused target DT and the cross section of the main pulse laser beam MPL when irradiating the diffused target DT in this embodiment. When the droplet target DL is irradiated with the pre-pulse laser beam PPL having S polarization, the diffused target DT tends to spread into an elliptical shape that is elongated in the Y direction, as shown by the dashed line in Fig. 8. The cross section of the main pulse laser beam MPL shown by the solid line in Fig. 8 will be described later. Note that when the droplet target DL is irradiated with the pre-pulse laser beam PPL having P polarization, the diffused target DT tends to spread into an elliptical shape that is elongated in the X direction.

[0065] Next, the processor 121 of this embodiment measures the length of the diffused target DT in the longitudinal direction and the length of the diffused target DT in the direction perpendicular to the longitudinal direction from a signal related to the shape of the diffused target DT imaged by the target sensor 27. Then, the processor 121 controls the actuator 155b based on the measurement result to adjust the distance between the cylindrical concave lens 159a and the cylindrical convex lens 159b. Furthermore, the processor 121 controls the actuator 155a based on the measurement result to rotate the housing 157 around the optical axis of the main pulse laser beam MPL.

[0066] Next, as in the comparative example, the main pulse laser device 130 emits a main pulse laser beam MPL, which passes through the cylindrical concave lens 159a and the cylindrical convex lens 159b of the shaping unit 150. The main pulse laser beam MPL is then reflected by the mirror 32, passes through the optical path combining member 34 and the window 12, is reflected by the mirrors 13A and 13B, and is irradiated onto the diffused target DT. The cross section of the main pulse laser beam MPL perpendicular to the optical axis of the main pulse laser beam MPL irradiated onto the diffused target DT is shaped by the shaping unit 150 into an elliptical shape that is longer in the polarization direction of the pre-pulse laser beam PPL than in any other direction. By adjusting the distance as described above, the length of the cross section of the main pulse laser beam MPL in the longitudinal direction approaches the length of the diffused target DT in the longitudinal direction. In FIG. 8 , the length of the main pulse laser beam MPL indicated by a solid line is indicated by L1, and for ease of viewing, the main pulse laser beam MPL is slightly longer than the diffused target DT. The length L1 is shortened as the distance shortens, and lengthened as the distance lengthens. The processor 121 adjusts the distance so that the length L1 is between 20 μm and 100 μm. Furthermore, by rotating the housing 157, the cylindrical concave lens 159a and the cylindrical convex lens 159b rotate, and the tilt of the major axis of the cross section of the main pulse laser beam MPL relative to the X direction when the diffused target DT is irradiated is adjusted. For the pre-pulse laser beam PPL having S polarization when irradiating the droplet target DL, the processor 121 rotates the main pulse laser beam MPL so that the elliptical cross section is elongated vertically in the Y direction, as shown in FIG. 8 . For the pre-pulse laser beam PPL having P polarization when irradiating the droplet target DL, the processor 121 rotates the main pulse laser beam MPL so that the elliptical cross section is elongated vertically in the X direction. By adjusting the distance and the tilt of the major axis, deviation of the irradiation of the main pulse laser beam MPL with respect to the diffused target DT is suppressed.

[0067] The main pulse laser beam MPL, whose length L1 and tilt of the major axis have been adjusted, is irradiated onto the diffused target DT, and EUV light 101 is emitted from the diffused target DT.

[0068] 4.3 Actions and Effects As described above, in this embodiment, the cross section perpendicular to the optical axis of the main pulse laser beam MPL when irradiated onto the diffused target DT has a shape that is longer in the polarization direction of the pre-pulse laser beam PPL when irradiated onto the droplet target DL than in any other direction.

[0069] The pre-pulse laser beam irradiation system PPS irradiates a droplet target DL discharged from the target supply unit 40 into the chamber apparatus 10 with a pre-pulse laser beam PPL to generate a diffused target DT. The generated diffused target DT tends to spread into a shape that is longer in the polarization direction of the pre-pulse laser beam PPL than in any other direction when the droplet target DL is irradiated with the pre-pulse laser beam PPL. In the above configuration, when the diffused target DT is irradiated with the main pulse laser beam MPL, the cross section perpendicular to the optical axis of the main pulse laser beam MPL is longer in the polarization direction of the pre-pulse laser beam PPL than in any other direction. Therefore, compared to when the cross section of the main pulse laser beam MPL is circular and the diameter of the circle is shorter than the length of the diffused target DT in the polarization direction of the pre-pulse laser beam PPL, it is possible to prevent the main pulse laser beam MPL from not irradiating a portion of the diffused target DT. Therefore, the droplet target DL may be more easily converted into plasma. Conversely, compared to when the diameter of the circle is longer than the length of the diffused target DT in the polarization direction of the pre-pulse laser beam PPL, loss of the main pulse laser beam MPL may be reduced. Therefore, the EUV light generation system 100 of this embodiment can generate the EUV light 101 efficiently.

[0070] Furthermore, the shaping unit 150 of this embodiment includes a cylindrical concave lens 159a, a cylindrical convex lens 159b, and an actuator 155b that adjusts the distance between the cylindrical concave lens 159a and the cylindrical convex lens 159b. In the above configuration, the length in the longitudinal direction of the cross section of the main pulse laser beam MPL when irradiated onto the diffused target DT can be adjusted by adjusting the distance between the cylindrical concave lens 159a and the cylindrical convex lens 159b with the actuator 155b. Therefore, the diffused target DT can be irradiated with a main pulse laser beam MPL having an appropriate cross section.

[0071] Furthermore, the processor 121 controls the adjustment of the distance between the cylindrical concave lens 159a and the cylindrical convex lens 159b using the actuator 155b. This reduces the burden on the administrator of the EUV light generation apparatus 100 for this adjustment, compared to when the administrator manually adjusts the distance between the cylindrical concave lens 159a and the cylindrical convex lens 159b.

[0072] Furthermore, the shaping unit 150 is disposed upstream of the optical path combining member 34 in the traveling direction of the main pulse laser beam MPL. According to the above configuration, only the main pulse laser beam MPL travels to the shaping unit 150. Therefore, the shaping unit 150 can shape only the cross section of the main pulse laser beam MPL when it is irradiated onto the diffused target DT into a shape that is longer in the polarization direction of the pre-pulse laser beam PPL when it is irradiated onto the droplet target DL than in any other direction.

[0073] In the EUV light generation system 100 of this embodiment, the main pulse laser beam MPL and the pre-pulse laser beam PPL may have different wavelengths but may have the same or different polarization directions. In this case, the beam combining member 34 is a dichroic mirror. Alternatively, the main pulse laser beam MPL and the pre-pulse laser beam PPL may be laser beams having the same wavelength but polarization directions that differ by 90°. In this case, the beam combining member 34 is a polarizer. In this case, the main pulse laser device 130 and the pre-pulse laser device 140 may both be YAG laser devices or CO laser devices, for example. By matching the polarization direction of the polarizer with the polarization direction of the main pulse laser beam MPL, the main pulse laser beam MPL passes through the polarizer. Alternatively, by changing the polarization direction of the polarizer to match the polarization direction of the pre-pulse laser beam PPL, the polarizer reflects the pre-pulse laser beam PPL.

[0074] 5. Description of the extreme ultraviolet light generation device according to the second embodiment Next, a description will be given of the configuration of an EUV light generation system 100 according to embodiment 2. Note that the same components as those described above are denoted by the same reference numerals, and redundant description will be omitted unless otherwise specified.

[0075] 5.1 Configuration 9 is a schematic diagram showing an example of the overall configuration of an EUV light generation system 100 according to this embodiment. The EUV light generation system 100 according to this embodiment is an EUV light generation system 100 that emits EUV light 101 toward an inspection system 300, not an exposure system 200. In this case, the EUV light generation system 100 according to this embodiment may have a limited collection solid angle of the EUV light collector mirror 75 for the EUV light 101, compared to an EUV light generation system 100 that emits the EUV light 101 toward the exposure system 200. By limiting the collection solid angle, the EUV light collector mirror 75 can be made smaller than when used in an EUV light generation system 100 that emits the EUV light 101 toward the exposure system 200. Therefore, in the EUV light generation system 100 of this embodiment, the EUV collector mirror 75 is disposed not around the entire circumference of the optical axis of the pre-pulse laser beam PPL when the droplet target DL is irradiated with the pre-pulse laser beam PPL, but only around a portion of the optical axis. That is, the EUV collector mirror 75 is disposed at a position offset to the side from the optical axis of the pre-pulse laser beam PPL when the droplet target DL is irradiated with the pre-pulse laser beam PPL. The EUV collector mirror 75 is also disposed within a predetermined range to the side of the optical axis. FIG. 10 is a diagram showing the position of the EUV collector mirror 75 relative to the optical axis of the pre-pulse laser beam PPL when generating the diffused target DT, viewed from the Y direction. The predetermined range of the EUV collector mirror 75 is, for example, a range of 33° to 105° with respect to the optical axis of the pre-pulse laser beam PPL when the droplet target DL is irradiated with the pre-pulse laser beam PPL.

[0076] In the EUV light generation system 100 of this embodiment, the main pulse laser device 130 emits a main pulse laser beam MPL polarized in the X direction, and the pre-pulse laser device 140 emits a pre-pulse laser beam PPL polarized in the X direction. In the EUV light generation system 100 of this embodiment, the main pulse laser beam MPL and the pre-pulse laser beam PPL have the same wavelength. Therefore, the beam path combining member 34 is a polarizer.

[0077] Now, a case will be described in which, unlike the present embodiment, the diffused target DT is generated by a pre-pulse laser beam PPL polarized in the X direction. In this case, as shown in Fig. 10 , the diffused target DT tends to spread in the X direction, which is the polarization direction of the pre-pulse laser beam PPL when it is irradiated onto the droplet target DL, and debris 171 generated from the diffused target DT tends to scatter in the X direction. When the EUV collector mirror 75 is positioned within a predetermined range, the EUV collector mirror 75 is located at the destination of the debris 171, and therefore the debris 171 may scatter and adhere to the EUV collector mirror 75.

[0078] Therefore, the EUV light generation system 100 of this embodiment differs from the pre-pulse laser beam irradiation system PPS of the first embodiment in that the pre-pulse laser beam irradiation system PPS includes a λ / 2 wave plate 141 as shown in Fig. 9. The λ / 2 wave plate 141 is arranged upstream of the optical path combining member 34 with respect to the traveling direction of the pre-pulse laser beam PPL. Fig. 9 shows an example in which the λ / 2 wave plate 141 is arranged between the mirror 33 and the optical path combining member 34.

[0079] 11 is a view of the diffused target DT generated by the pre-pulse laser beam PPL as viewed from the Y direction. The λ / 2 wavelength plate 141 changes the polarization direction of the pre-pulse laser beam PPL when it is irradiated onto the droplet target DL to a direction different from the direction from the optical axis of the pre-pulse laser beam PPL toward the EUV light collector mirror 75 when it is irradiated onto the droplet target DL. The λ / 2 wavelength plate 141 rotates the polarization direction of the pre-pulse laser beam PPL polarized in the X direction to change the pre-pulse laser beam PPL into a pre-pulse laser beam PPL polarized in the Y direction. That is, the λ / 2 wavelength plate 141 changes the polarization direction of the pre-pulse laser beam PPL when it is irradiated onto the droplet target DL to the Y direction, which is perpendicular to the XZ plane including the central axis C1 of the EUV light 101 traveling from the plasma generation region AR to the EUV light collector mirror 75 and the central axis C2 of the EUV light 101 reflected by the EUV light collector mirror 75.

[0080] 5.2 Actions and Effects FIG. 12 is a view of the diffused target DT shown in FIG. 11 as viewed from the Z direction. As shown in FIGS. 11 and 12 , the EUV collector mirror 75 of this embodiment is positioned offset laterally from the optical axis of the pre-pulse laser beam PPL when irradiating the droplet target DL so as not to cross a line passing through the plasma generation region AR and extending in the polarization direction of the pre-pulse laser beam PPL when irradiating the droplet target DL. The diffused target DT generated by the pre-pulse laser beam PPL polarized in the Y direction tends to spread in the Y direction, which is the polarization direction of the pre-pulse laser beam PPL when irradiating the droplet target DL. Furthermore, debris 171 generated from the diffused target DT tends to scatter in the Y direction. This can prevent the debris 171 from scattering toward the EUV collector mirror 75. Furthermore, preventing the debris 171 from adhering to the EUV collector mirror 75 can prevent malfunctions of the EUV light generation apparatus 100.

[0081] 6. Description of the extreme ultraviolet light generation device according to the third embodiment Next, a description will be given of the configuration of an EUV light generation system 100 according to embodiment 3. Note that the same components as those described above are denoted by the same reference numerals, and redundant description will be omitted unless otherwise specified.

[0082] 6.1 Configuration 13 is a schematic diagram showing an example of the overall configuration of an EUV light generation system 100 of this embodiment. In the EUV light generation system 100 of this embodiment, the configurations of the main pulse laser beam irradiation system MPS and the pre-pulse laser beam irradiation system PPS are different from those of the second embodiment.

[0083] The main pulse laser beam irradiation system MPS of this embodiment includes a main pulse laser device 130, mirrors 31 and 32, a shaping unit 150, a λ / 2 wavelength plate 131, a laser beam focusing mirror 13D, and a high-reflection mirror 13E.

[0084] The λ / 2 wave plate 131 is arranged downstream of the shaping unit 150 with respect to the traveling direction of the main pulse laser beam MPL. FIG. 13 shows an example in which the λ / 2 wave plate 131 is arranged upstream of the mirror 32. FIG. 14 is a diagram of the diffused target DT irradiated with the main pulse laser beam MPL polarized in the Y direction, viewed from the Y direction. The λ / 2 wave plate 131 changes the polarization direction of the main pulse laser beam MPL when irradiating the diffused target DT to a direction different from the direction from the optical axis of the main pulse laser beam MPL toward the EUV light collector mirror 75 when irradiating the diffused target DT. The λ / 2 wave plate 131 rotates the polarization direction of the main pulse laser beam MPL polarized in the X direction, and converts the main pulse laser beam MPL into a main pulse laser beam MPL polarized in the Y direction. That is, the λ / 2 wave plate 131 changes the polarization direction of the main pulse laser beam MPL when it is irradiated onto the diffused target DT in the Y direction perpendicular to the XZ plane including the central axes C1 and C2. The main pulse laser beam MPL is reflected by the mirror 32, passes through the window 12a provided in the inner wall 10b of the chamber apparatus 10, and proceeds to the laser beam focusing mirror 13D, as shown in FIG.

[0085] The laser beam focusing mirror 13D and the high-reflection mirror 13E are included in the laser focusing optical system 13 and are arranged in the internal space of the chamber apparatus 10. The laser beam focusing mirror 13D reflects and focuses the main pulse laser beam MPL that passes through the window 12a. The high-reflection mirror 13E reflects the light focused by the laser beam focusing mirror 13D to the plasma generation region AR. The positions of the laser beam focusing mirror 13D and the high-reflection mirror 13E are adjusted by the laser beam manipulator 13C so that the focusing position of the main pulse laser beam MPL in the internal space of the chamber apparatus 10 is a position specified by the processor 121. The focusing position is adjusted to be directly below the nozzle 42.

[0086] The pre-pulse laser beam irradiation system PPS of this embodiment includes a pre-pulse laser device 140, a mirror 33, a λ / 2 wavelength plate 141, a mirror 35, a laser beam focusing mirror 13A, and a high-reflection mirror 13B.

[0087] The mirror 35 is disposed between the λ / 2 wave plate 141 and the laser beam focusing mirror 13A, and reflects the pre-pulse laser beam 140 from the mirror 35 toward the laser beam focusing mirror 13A.

[0088] In this embodiment, the main pulse laser beam MPL and the pre-pulse laser beam PPL have the same polarization, i.e., polarization in the X direction, so a polarizer is not used. Furthermore, in this embodiment, the main pulse laser beam MPL and the pre-pulse laser beam PPL have the same wavelength, so a dichroic mirror is not used. Because a polarizer and a dichroic mirror are not used, the optical paths of the main pulse laser beam MPL and the pre-pulse laser beam PPL in this embodiment are separate and do not overlap upstream of the plasma generation region AR. If the main pulse laser beam MPL and the pre-pulse laser beam PPL have different wavelengths, a dichroic mirror may be used, and the optical paths of the main pulse laser beam MPL and the pre-pulse laser beam PPL may overlap downstream of the λ / 2 wave plates 131, 141 by the dichroic mirror.

[0089] 6.2 Actions and Effects FIG. 15 is a view of the diffused target DT shown in FIG. 14 as viewed from the Z direction. As shown in FIGS. 14 and 15 , the EUV collector mirror 75 of this embodiment is disposed at a position offset laterally from the optical axis of the main pulse laser beam MPL when irradiating the diffused target DT so as not to cross a line passing through the plasma generation region AR and extending in the polarization direction of the main pulse laser beam MPL when irradiating the diffused target DT. When irradiated with the main pulse laser beam MPL polarized in the Y direction, the diffused target DT tends to diffuse in the Y direction, which is the polarization direction of the main pulse laser beam MPL when irradiating the diffused target DT. Furthermore, debris 171 generated from the diffused target DT tends to scatter in the Y direction. This can prevent the debris 171 from scattering toward the EUV collector mirror 75. Furthermore, by preventing the debris 171 from adhering to the EUV collector mirror 75, malfunctions of the EUV light generation apparatus 100 can be prevented.

[0090] The above description is intended to be illustrative rather than limiting. Thus, it will be apparent to one skilled in the art that modifications can be made to the disclosed embodiments without departing from the scope of the claims. It will also be apparent to one skilled in the art that the disclosed embodiments can be used in combination. Terms used throughout this specification and claims should be construed as "open ended" unless expressly stated otherwise. For example, words such as "comprise," "have," "comprise," and "equip" should be construed as meaning "without excluding the presence of elements other than those listed." In addition, the modifier "a" should be construed as meaning "at least one" or "one or more." In addition, the term "at least one of A, B, and C" should be construed as "A," "B," "C," "A+B," "A+C," "B+C," or "A+B+C," and should also be construed as including combinations other than "A," "B," and "C."

Claims

1. a target supply unit that discharges a droplet target into the chamber apparatus; a pre-pulse laser light irradiation system that irradiates the droplet target with a linearly polarized pre-pulse laser light to generate a diffused target; a main pulse laser light irradiation system that irradiates the diffused target with a main pulse laser light to generate extreme ultraviolet light; an extreme ultraviolet light focusing mirror that reflects the extreme ultraviolet light; Equipped with a cross section perpendicular to an optical axis of the main pulse laser beam when irradiating the diffused target is longer in a polarization direction of the pre-pulse laser beam when irradiating the droplet target than in any other direction; the main pulse laser beam when irradiated onto the diffused target has linear polarization, The polarization direction of the main pulse laser beam when irradiating the diffused target is perpendicular to a plane including a central axis of the extreme ultraviolet light traveling to the extreme ultraviolet focusing mirror and a central axis of the extreme ultraviolet light reflected by the extreme ultraviolet focusing mirror. Extreme ultraviolet light generator.

2. 2. The extreme ultraviolet light generating apparatus according to claim 1, The cross section of the main pulse laser beam when irradiating the diffused target is elliptical.

3. 2. The extreme ultraviolet light generating apparatus according to claim 1, The main pulse laser beam irradiation system includes a shaping unit that shapes the cross section of the main pulse laser beam when irradiated onto the diffused target into a shape that is longer in the polarization direction of the pre-pulse laser beam when irradiated onto the droplet target than in any other direction.

4. The extreme ultraviolet light generating apparatus according to claim 3, the optical path combining member is arranged at a position where an optical path of the pre-pulse laser beam and an optical path of the main pulse laser beam intersect, and the optical path combining member overlaps the optical path of the pre-pulse laser beam and the optical path of the main pulse laser beam, The shaping unit is disposed upstream of the optical path combining member in the traveling direction of the main pulse laser beam.

5. The extreme ultraviolet light generating apparatus according to claim 3, The shaping unit is a cylindrical concave lens; a cylindrical convex lens facing the cylindrical concave lens; an actuator that moves at least one of the cylindrical concave lens and the cylindrical convex lens to adjust the distance between the cylindrical concave lens and the cylindrical convex lens; Includes.

6. 2. The extreme ultraviolet light generating apparatus according to claim 1, The extreme ultraviolet light focusing mirror is disposed at a position offset laterally from the optical axis of the main pulse laser beam when it is irradiated onto the diffused target so as not to cross a line that passes through a plasma generation region in which the extreme ultraviolet light is generated in the chamber apparatus and that extends in the polarization direction of the main pulse laser beam when it is irradiated onto the diffused target.

7. 2. The extreme ultraviolet light generating apparatus according to claim 1, The main pulse laser beam irradiation system includes a λ / 2 wave plate that changes the polarization direction of the main pulse laser beam when irradiating the diffused target to a direction perpendicular to a plane that includes a central axis of the extreme ultraviolet beam traveling toward the extreme ultraviolet focusing mirror and a central axis of the extreme ultraviolet beam reflected by the extreme ultraviolet focusing mirror.

8. The extreme ultraviolet light generating apparatus according to claim 7, the main pulse laser beam irradiation system includes a shaping unit that shapes the cross section of the main pulse laser beam when irradiating the diffused target into a shape that is longer in the polarization direction of the pre-pulse laser beam when irradiating the droplet target than in any other direction; The λ / 2 wave plate is disposed downstream of the shaping unit in the direction in which the main pulse laser beam travels.

9. 2. The extreme ultraviolet light generating apparatus according to claim 1, The polarization direction of the pre-pulse laser beam when irradiated onto the droplet target is perpendicular to a plane including the central axis of the extreme ultraviolet light traveling toward the extreme ultraviolet focusing mirror and the central axis of the extreme ultraviolet light reflected by the extreme ultraviolet focusing mirror.

10. The extreme ultraviolet light generating apparatus according to claim 9, The extreme ultraviolet light focusing mirror is disposed at a position offset to the side from the optical axis of the pre-pulse laser beam when it is irradiated onto the droplet target so as not to cross a line that passes through a plasma generation region in which the extreme ultraviolet light is generated in the chamber apparatus and that extends in the polarization direction of the pre-pulse laser beam when it is irradiated onto the diffused target.

11. The extreme ultraviolet light generating apparatus according to claim 9, The pre-pulse laser beam irradiation system includes a λ / 2 wave plate that changes the polarization direction of the pre-pulse laser beam when irradiated onto the droplet target to a direction perpendicular to a plane including a central axis of the extreme ultraviolet beam traveling toward the extreme ultraviolet beam focusing mirror and a central axis of the extreme ultraviolet beam reflected by the extreme ultraviolet beam focusing mirror.

12. The extreme ultraviolet light generating apparatus according to claim 11, the optical path combining member is arranged at a position where an optical path of the pre-pulse laser beam and an optical path of the main pulse laser beam intersect, and the optical path combining member overlaps the optical path of the pre-pulse laser beam and the optical path of the main pulse laser beam, The λ / 2 wave plate is disposed upstream of the optical path combining member in the traveling direction of the pre-pulse laser beam.

13. 2. The extreme ultraviolet light generating apparatus according to claim 1, The wavelength of the main pulse laser beam and the wavelength of the pre-pulse laser beam are different from each other.

14. 2. The extreme ultraviolet light generating apparatus according to claim 1, The wavelength of the main pulse laser beam and the wavelength of the pre-pulse laser beam are the same.

15. a target supply unit that discharges a droplet target into the chamber apparatus; a pre-pulse laser light irradiation system that irradiates the droplet target with a linearly polarized pre-pulse laser light to generate a diffused target; a main pulse laser light irradiation system that irradiates the diffused target with a main pulse laser light to generate extreme ultraviolet light; an extreme ultraviolet light focusing mirror that reflects the extreme ultraviolet light; Equipped with a cross section perpendicular to an optical axis of the main pulse laser beam when irradiating the diffused target is longer in a polarization direction of the pre-pulse laser beam when irradiating the droplet target than in any other direction; the main pulse laser beam when irradiated onto the diffused target has linear polarization, The polarization direction of the main pulse laser beam when irradiating the diffused target is perpendicular to a plane including a central axis of the extreme ultraviolet light traveling to the extreme ultraviolet focusing mirror and a central axis of the extreme ultraviolet light reflected by the extreme ultraviolet focusing mirror. irradiating a mask with the extreme ultraviolet light generated by the extreme ultraviolet light generating device to inspect the mask for defects; selecting a mask using the results of said testing; The pattern formed on the selected mask is transferred onto a photosensitive substrate by exposure. A method for manufacturing an electronic device, comprising:

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