A high repetition rate extreme ultraviolet radiation light source and EUV lithography light source

Abstract

The present invention provides a high-repetition-rate extreme ultraviolet radiation light source and an EUV lithography machine light source, wherein a portion of the target laser pulses is incident on a megawatt-class optical gain cavity to generate a second infrared laser pulse with a megawatt average power; another portion of the target laser pulses is incident on a room-temperature very high frequency photocathode microwave electron gun after frequency doubling and shaping, driving the room-temperature very high frequency photocathode microwave electron gun to generate a continuous picosecond electron beam with a repetition rate of hundreds of megahertz; the continuous picosecond electron beam is incident on the megawatt-class optical gain cavity and undergoes inverse Compton scattering with the second infrared laser pulse to generate radiation in the extreme ultraviolet band; further, by adjusting the energy of the continuous picosecond electron beam and the laser incident angle, the wavelength of the scattered light can be adjusted within a certain range, thereby realizing a high-repetition-rate extreme ultraviolet radiation light source.

Description

Technical Field

[0001] The present invention relates to the field of extreme ultraviolet science and technology, and more specifically, to an extreme ultraviolet radiation light source with a high repetition rate and an EUV lithography machine light source. Background Art

[0002] Extreme ultraviolet light refers to electromagnetic radiation with a wavelength between 121nm and 10nm. Its photon energy is high and can ionize an atom or molecule without breaking the molecule down. Therefore, extreme ultraviolet light can analyze the fine structure of molecular clusters and is widely used in energy, chemistry, biology and other fields.

[0003] Extreme ultraviolet light has a short wavelength, enabling very small feature sizes and very high resolution. In particular, extreme ultraviolet light with a wavelength of approximately 10nm-14nm can be used in EUV lithography machines (Extreme Ultra-violet, EUV for short, often referred to as EUV lithography), producing chips with smaller nanometer dimensions and more powerful functions. Therefore, extreme ultraviolet light has broad application prospects in industrial applications, biomedicine, and basic research in many disciplines, and has therefore attracted widespread attention from scientists at home and abroad. Obviously, developing EUV radiation light sources that meet application needs is a research hotspot in related fields.

[0004] For EUV light sources required for high-capacity chip production and testing, on the one hand, the repetition frequency of the light source should be increased to improve the efficiency of production and testing, and on the other hand, the power of the light source should be increased to meet the dose required for lithography or imaging.

[0005] Currently used advanced EUV light source technologies are laser plasma sources, with maximum powers in the hundreds of watts and maximum repetition rates of hundreds of kilohertz. Another EUV light source technology under development is accelerator-based radiation sources, including synchrotron EUV sources generated by storage rings and EUV free-electron lasers (FELs). The combined power of these two sources can reach kilowatts. EUV synchrotron radiation is broadband, with power within a specific bandwidth limited to tens of watts; EUV FELs are narrowband coherent radiation, with power reaching tens of kilowatts within the required bandwidth.

[0006] However, EUV light sources based on synchrotron radiation and free electron lasers require large-scale acceleration units and magnet structures, and are expensive. In particular, the superconducting accelerator technology required for high-repetition-rate EUV light sources is not yet mature.

[0007] Therefore, developing an extreme ultraviolet radiation source with a compact structure, relatively easy technical implementation, and high repetition rate is of great significance to the development of extreme ultraviolet science and technology. Summary of the Invention

[0008] In view of this, in order to solve the above problems, the present invention provides a high repetition rate extreme ultraviolet radiation light source and an EUV lithography light source, and the technical solution is as follows:

[0009] A high repetition rate extreme ultraviolet radiation light source, comprising:

[0010] Ytterbium-doped femtosecond optical fiber master oscillator, used to generate the first infrared laser pulses with hundreds of megahertz milliwatt power;

[0011] a chirped pulse amplification system, configured to process the first infrared laser pulse to generate a picosecond laser pulse with a watt-level power;

[0012] a cryogenically cooled two-channel amplifier for processing the picosecond laser pulses to generate target laser pulses with an average power of more than kilowatts;

[0013] Among them, a part of the target laser pulses is incident on a megawatt-class optical gain cavity to generate a second infrared laser pulse with an average power of megawatts; another part of the target laser pulses is incident on a room-temperature very high frequency photocathode microwave electron gun after frequency doubling and shaping, driving the room-temperature very high frequency photocathode microwave electron gun to generate a continuous picosecond electron beam with a repetition frequency of hundreds of megahertz; the continuous picosecond electron beam is incident on the megawatt-class optical gain cavity, and undergoes inverse Compton scattering with the second infrared laser pulse to generate extreme ultraviolet band radiation.

[0014] Preferably, in the above-mentioned extreme ultraviolet radiation light source, the chirped pulse amplification system includes:

[0015] a chirped body Bragg grating pulse stretcher, configured to stretch the first infrared laser pulse to generate a first transition laser pulse with a sub-milliwatt power;

[0016] The preamplifier and the optical fiber amplifier are used to sequentially amplify the first transition laser pulse twice to generate a second transition laser pulse;

[0017] A chirped body Bragg grating pulse compressor is used to compress the second transition laser pulse to generate the picosecond laser pulse.

[0018] Preferably, in the above-mentioned extreme ultraviolet radiation light source, the low-temperature cooled two-channel amplifier comprises:

[0019] A first beam splitter, a first beam combiner, a cryogenically cooled Yb:YAG crystal, a first optical fiber coupled laser diode, and a second optical fiber coupled laser diode;

[0020] The first fiber-coupled laser diode corresponds to the first beam splitter;

[0021] The second optical fiber coupled laser diode corresponds to the first beam combiner;

[0022] The cryogenically cooled Yb:YAG crystal is located between the first beam splitter and the first beam combiner;

[0023] The picosecond laser pulse is combined with the first beam splitter, the first beam combiner, the first fiber-coupled laser diode and the second fiber-coupled laser diode to enter the cryogenically cooled Yb:YAG crystal for energy storage and amplification, thereby generating the target laser pulse.

[0024] Preferably, in the above-mentioned extreme ultraviolet radiation light source, the megawatt-class optical gain cavity comprises an input coupling mirror, a first plane mirror and two off-axis parabolic mirrors;

[0025] The target laser pulse is incident into the megawatt-class optical gain cavity through the input coupling mirror, and is stacked back and forth through the first plane mirror, the off-axis parabolic mirror and the input coupling mirror to generate the second infrared laser pulse.

[0026] Preferably, in the above-mentioned extreme ultraviolet radiation light source, the extreme ultraviolet radiation light source further comprises:

[0027] A frequency doubling system for performing frequency doubling processing on the target laser pulse incident on the room temperature very high frequency photocathode microwave electron gun;

[0028] The shaping system is used to shape the target laser pulse processed by the frequency doubling system so as to be incident on the room temperature very high frequency photocathode microwave electron gun.

[0029] Preferably, in the above-mentioned extreme ultraviolet radiation light source, the extreme ultraviolet radiation light source further comprises:

[0030] A solenoid coil is used to perform magnetic field focusing on the continuous picosecond electron beam.

[0031] Preferably, in the above-mentioned extreme ultraviolet radiation light source, the extreme ultraviolet radiation light source further comprises: a control system and a power source;

[0032] The control system is used to control the working state of the power source and the ytterbium-doped femtosecond optical master oscillator;

[0033] The power source is used to provide microwave power to the room temperature very high frequency photocathode microwave electron gun and perform phase adjustment.

[0034] Preferably, in the above-mentioned extreme ultraviolet radiation light source, the extreme ultraviolet radiation light source further comprises:

[0035] A second plane mirror, a second beam splitter and a third plane mirror are sequentially positioned between the cryogenically cooled two-channel amplifier and the megawatt optical gain cavity.

[0036] Preferably, in the above-mentioned extreme ultraviolet radiation light source, the extreme ultraviolet radiation light source further comprises:

[0037] A fourth plane mirror and a fifth plane mirror are located between the second beam splitter and the room temperature very high frequency photocathode microwave electron gun.

[0038] A light source for an EUV lithography machine, comprising any one of the extreme ultraviolet radiation light sources described above.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention provides a high-repetition-rate extreme ultraviolet radiation source. A portion of the target laser pulses is incident on a megawatt-class optical gain cavity to generate a second infrared laser pulse with a megawatt average power. Another portion of the target laser pulses, after undergoing frequency-doubling and shaping, is incident on a room-temperature very high frequency photocathode microwave electron gun, which drives the gun to generate a continuous picosecond electron beam with a repetition rate of hundreds of megahertz. This continuous picosecond electron beam is incident on the megawatt-class optical gain cavity and undergoes inverse Compton scattering with the second infrared laser pulse to generate radiation in the extreme ultraviolet band. Furthermore, by adjusting the energy of the continuous picosecond electron beam and the laser incident angle, the wavelength of the scattered light can be adjusted within a certain range, thus achieving a high-repetition-rate extreme ultraviolet radiation source. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0042] Figure 1 A schematic diagram of the principle structure of a high repetition rate extreme ultraviolet radiation light source provided by an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of the distribution of electric field intensity and magnetic induction intensity at different longitudinal positions of an accelerator provided by an embodiment of the present invention;

[0044] Figure 3 A schematic diagram of the distribution of electron beam transverse parameters at different longitudinal positions of an accelerator provided by an embodiment of the present invention;

[0045] Figure 4 A schematic diagram of the change in laser spot size along the optical axis in a megawatt-class optical gain cavity provided by an embodiment of the present invention;

[0046] Figure 5A schematic diagram of the variation of scattered photon number density with scattering angle provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] refer to Figure 1 , Figure 1 A schematic diagram of the principle structure of a high repetition rate extreme ultraviolet radiation light source provided by an embodiment of the present invention.

[0050] The extreme ultraviolet radiation light source comprises:

[0051] The Ytterbium-doped femtosecond optical fiber master oscillator 1 is used to generate the first infrared laser pulse with a power of 100 MHz and milliwatts.

[0052] The chirped pulse amplification system 2 is used to process the first infrared laser pulse to generate a picosecond laser pulse with a watt-level power.

[0053] The low-temperature cooled two-channel amplifier 3 is used to process the picosecond laser pulses to generate target laser pulses with an average power of more than 1 kilowatt.

[0054] Among them, a part of the target laser pulse is incident on the megawatt optical gain cavity 4 to generate a second infrared laser pulse with an average power of megawatts; another part of the target laser pulse is incident on the room temperature very high frequency photocathode microwave electron gun 12 after frequency doubling and shaping, driving the room temperature very high frequency photocathode microwave electron gun 12 to generate a continuous picosecond electron beam with a repetition frequency of hundreds of megahertz; the continuous picosecond electron beam is incident on the megawatt optical gain cavity 4, and undergoes inverse Compton scattering with the second infrared laser pulse to generate extreme ultraviolet band radiation.

[0055] Specifically, by adjusting the energy of the continuous picosecond electron beam and the laser incident angle, the wavelength of the scattered light can be adjusted within a certain range, thus realizing a high repetition rate extreme ultraviolet radiation light source.

[0056] Optionally, in another embodiment of the present invention, as Figure 1 As shown, the chirped pulse amplification system 2 includes:

[0057] The chirped volume Bragg grating pulse stretcher 201 is used to stretch the first infrared laser pulse to generate a first transition laser pulse with sub-milliwatt power. For example, the first transition laser pulse is a longer laser pulse with sub-milliwatt power.

[0058] The preamplifier 202 and the fiber amplifier 203 are used to amplify the first transition laser pulse twice in sequence to generate a second transition laser pulse. For example, the second transition laser pulse is a laser pulse that amplifies a sub-milliwatt stretched pulse to tens of milliwatts.

[0059] The chirped body Bragg grating pulse compressor 204 is configured to compress the second transition laser pulse to generate the picosecond laser pulse.

[0060] Optionally, in another embodiment of the present invention, as Figure 1 As shown, the cryogenically cooled two-channel amplifier 3 includes: a first beam splitter 8a, a first beam combiner 9, a cryogenically cooled Yb:YAG crystal 301, a first optically coupled laser diode 302 and a second optically coupled laser diode 303.

[0061] The first fiber-coupled laser diode 302 corresponds to the first beam splitter 8 a.

[0062] The second optical fiber coupled laser diode 303 corresponds to the first beam combiner 9 .

[0063] The cryogenically cooled Yb:YAG crystal 301 is located between the first beam splitter 8 a and the first beam combiner 9 .

[0064] The picosecond laser pulse is combined with the first beam splitter 8a, the first beam combiner 9, the first fiber-coupled laser diode 302 and the second fiber-coupled laser diode 303 to enter the cryogenically cooled Yb:YAG crystal 301 for energy storage and amplification, thereby generating the target laser pulse.

[0065] Specifically, a watt-level picosecond laser pulse enters the cryogenically cooled Yb:YAG crystal 301 for energy storage and amplification, and passes through the first beam splitter 8a and the first beam combiner 9 multiple times, wherein the entire amplifier power is driven by two fiber-coupled laser diodes.

[0066] Optionally, in another embodiment of the present invention, as Figure 1 As shown, the megawatt-class optical gain cavity 4 includes an input coupling mirror 401 , a first plane mirror 7 a and two off-axis parabolic mirrors 402 .

[0067] The target laser pulse is incident into the megawatt optical gain cavity 4 through the input coupling mirror 401 , and is stacked back and forth through the first plane mirror 7 a , the off-axis parabolic mirror 402 and the input coupling mirror 401 to generate the second infrared laser pulse.

[0068] Optionally, in another embodiment of the present invention, as Figure 1 As shown, the extreme ultraviolet radiation light source further includes:

[0069] The frequency doubling system 5 is used to perform frequency doubling processing on the target laser pulse incident to the room temperature very high frequency photocathode microwave electron gun 12 .

[0070] The shaping system 6 is used to shape the target laser pulse processed by the frequency doubling system 5 so as to be incident on the room temperature very high frequency photocathode microwave electron gun 12 .

[0071] Optionally, in another embodiment of the present invention, as Figure 1 As shown, the extreme ultraviolet radiation light source further includes:

[0072] The transverse focusing structure 13 is used to focus the continuous picosecond electron beam.

[0073] Optionally, the transverse focusing structure 13 is described by taking a solenoid coil as an example in the embodiment of the present invention.

[0074] Optionally, in another embodiment of the present invention, as Figure 1 As shown, the extreme ultraviolet radiation light source further includes: a control system 10 and a power source 11 .

[0075] The control system 10 is used to control the working states of the power source 11 and the Yb-doped femtosecond optical master oscillator 1 .

[0076] The power source 11 is used to provide microwave power to the room temperature very high frequency photocathode microwave electron gun 12 and perform phase adjustment in real time.

[0077] Optionally, in another embodiment of the present invention, as Figure 1 As shown, the extreme ultraviolet radiation light source further includes:

[0078] The second plane mirror 7b, the second beam splitter 8b and the third plane mirror 7c are sequentially located between the cryogenically cooled two-channel amplifier 3 and the megawatt-class optical gain cavity 4.

[0079] The fourth plane mirror 7d and the fifth plane mirror 7e are located between the second beam splitter 8b and the room temperature very high frequency photocathode microwave electron gun 12.

[0080] based on Figure 1The high repetition rate extreme ultraviolet radiation source shown in the present invention uses an ytterbium-doped femtosecond fiber laser as a master oscillator, that is, the ytterbium-doped femtosecond fiber master oscillator 1 described in the present invention. The first infrared laser pulse with a power of hundreds of megahertz milliwatts generated by it is first pulse stretched by a chirped body Bragg grating pulse stretcher 201 in a chirped pulse amplification system 2, then amplified in two stages by a preamplifier 202 and a fiber amplifier 203, and finally compressed by a chirped body Bragg grating pulse compressor 204, ultimately generating a picosecond laser pulse with a power of watts. The picosecond laser pulse with a high frequency is incident on the low-temperature cooled two-channel amplifier 3 to obtain the target laser pulse with an average power of more than kilowatts, and then passes through the second plane mirror 7b to be incident on the second beam splitter 8b. The target laser pulse is split by the second beam splitter 8b, and a small part of the target laser pulse with power passes through the frequency doubling system 5, the shaping system 6, the fourth plane mirror 7d and the fifth plane mirror 7e in sequence and is incident on the room temperature very high frequency photocathode microwave electron gun 12, which is used to drive the room temperature very high frequency photocathode microwave electron gun 12 with a repetition rate of hundreds of megahertz to generate a continuous picosecond electron beam with a repetition rate of hundreds of megahertz.

[0081] The target laser pulse with the remaining kilowatt power is sent into the high-enhancement-multiple megawatt optical gain cavity 4 with a cavity length matching the repetition frequency of hundreds of megahertz through the third plane mirror 7c. In the megawatt optical gain cavity 4, the second infrared laser pulse with an average power of megawatts is realized by the back-and-forth stacking of pulses.

[0082] The energy of the electron bunch is increased to 2MeV in the electron gun body. After passing through the transverse focusing structure 13, the electron bunch enters the megawatt optical gain cavity 4 and undergoes inverse Compton scattering (collision) with the second infrared laser pulse with megawatt average power to generate extreme ultraviolet radiation.

[0083] The control system 10 is used to control the working states of the power source 11 and the Yb-doped femtosecond optical master oscillator 1; the power source 11 is used to provide microwave power to the room temperature very high frequency photocathode microwave electron gun 12 and perform phase adjustment in real time.

[0084] Moreover, by adjusting the electron beam energy and the laser incident angle, the wavelength of scattered light within a certain range can be adjusted; the electron beam energy is adjusted by the amplitude and phase of the microwave electric field, and different laser incident angles are achieved through the design of the optical cavity structure and the overall rotation of the optical cavity. Among them, 180-degree collision can be achieved by using a focusing and deflecting structure with a transmission hole (off-axis parabolic mirror) to allow the electron beam to pass through its center and collide head-on with the laser pulse.

[0085] Optionally, in the embodiment of the present invention, the structure of the megawatt-class optical gain cavity 4 may be a full-sphere mirror structure, a standard bow-tie structure or other structures.

[0086] Specifically, an ytterbium-doped femtosecond fiber laser is used as a master oscillator, with a frequency of 162.5 MHz, an output power of 58 mW, and a central wavelength of 1030 nm. Under the control of the pulse signal of the control system 10, a first infrared laser pulse with a power of 100 MHz and milliwatts is generated. After passing through the chirped pulse amplification system 2, a picosecond laser pulse with a power of watts is generated (for example, a picosecond laser pulse of 6 W and 4.5 ps). The pulse then enters the cryogenically cooled two-channel amplifier 3 to obtain a target laser pulse with an average power of more than kilowatts (for example, a target laser pulse of 1.2 kW). The pulse then passes through the second plane mirror 7 b to the second beam splitter 8 b for beam splitting processing. Most of the target laser pulse with a power of 1 kW (for example, a target laser pulse of 1 kW) is reflected by the third plane mirror 7 c and sent into a high-enhancement-multiple megawatt optical gain cavity 4 with a cavity length matching the repetition frequency of 100 MHz (for example, 1845 mm). In the megawatt optical gain cavity 4, a second infrared laser pulse with an average power of megawatts is achieved by back-and-forth stacking of pulses.

[0087] In addition, a small amount of target laser pulse with a power of 200W (for example, a target laser pulse with a power of 200W) is sequentially passed through the frequency doubling system 5, the shaping system 6, the fourth plane mirror 7d and the fifth plane mirror 7e to be incident on the room temperature very high frequency photocathode microwave electron gun 12, and serves as the driving laser of the room temperature very high frequency photocathode microwave electron gun 12 (the power of the driving laser is about 30W), and is used to drive the room temperature very high frequency photocathode microwave electron gun 12 with a repetition frequency of 100 MHz to generate a continuous picosecond electron beam with a repetition frequency of 100 MHz. Specifically, the driving laser irradiates the cathode material of the room temperature very high frequency photocathode microwave electron gun 12 to generate a continuous picosecond electron beam with a repetition frequency of 100 MHz (for example, it can be a continuous picosecond electron beam of 162 MHz and a pulse charge of 300 pC).

[0088] Optionally, the frequency doubling system 5 can perform a frequency doubling process on the target laser pulse of a small power, and the frequency of the subsequently obtainable driving laser is 515 nm and the power is about 30 W.

[0089] The electron bunch is accelerated by the microwave electric field in the electron gun body, so that its energy is increased to 2MeV. After passing through the transverse focusing structure 13, the electron bunch enters the megawatt optical gain cavity 4 and undergoes inverse Compton scattering (collision) with the second infrared laser pulse with an average power of megawatts to generate extreme ultraviolet radiation.

[0090] The power source 11 provides microwave power and phase regulation to the electron gun under the control of a pulse signal from a control system 10. This control system 10 also functions as a clock control. Its clock signal is provided by the fiber laser. The control system 10 provides two independently adjustable timing signals to control the timing of laser pulse generation and the microwave signal to adjust the time when the electron beam enters the electron gun, thereby precisely controlling the timing of scattering of the electron beam and the laser pulse.

[0091] refer to Figure 2 , Figure 2 A schematic diagram of the distribution of electric field intensity and magnetic induction intensity at different longitudinal positions of an accelerator provided by an embodiment of the present invention; wherein Figure 2 The solid line in the middle is the longitudinal magnetic induction intensity of the transverse focusing structure (the transverse focusing structure is illustrated here by taking a solenoid coil as an example), and the dotted line is the longitudinal electric field intensity of the room temperature very high frequency photocathode microwave electron gun.

[0092] refer to Figure 3 , Figure 3 A schematic diagram of the distribution of electron beam transverse parameters at different longitudinal positions of an accelerator provided by an embodiment of the present invention; Figure 3 The solid line is the rms size and the dashed line is the rms normalized emittance.

[0093] The longitudinal electric field intensity of the electron gun and the longitudinal magnetic induction intensity of the solenoid coil obtained through simulation optimization are shown in the following figure: Figure 2 As shown in the figure, the solenoid coil is about 400 mm long and its entrance is close to the nose of the cavity downstream of the electron gun accelerating gap (0.2 m from the photocathode). After beam dynamics tracking, the rms transverse size and transverse normalized emittance distribution of the electron beam at different longitudinal positions are obtained as shown in the figure. Figure 3 As shown, the electron beam obtains a minimum lateral dimension of 35 μm at a distance of 0.756 m from the photocathode, which is set as the beam waist of the optical gain cavity.

[0094] Based on the repetition rate setting and the design of a standard bow-tie optical gain cavity, the two off-axis parabolic mirrors were designed with a radius of curvature of 450mm and a spacing of 450.15mm. The angle at which the electron beam and laser pulse collided was set to 175°, which meant that the gain cavity's optical waist axis was set at a relative angle of 5° to the accelerator beamline axis. In this case, the focusing redirection structure did not require a transmission aperture.

[0095] In order to increase the power amplification, a high-precision gain cavity is required; the laser spot size variation period along the optical axis in a megawatt-level optical gain cavity is as follows: Figure 4 As shown, Figure 4 A schematic diagram of the change in laser spot size along the optical axis in a megawatt-class optical gain cavity provided by an embodiment of the present invention is provided. Figure 4In the middle, 402 indicates the location of two off-axis parabolic mirrors. The spot size here is 2.5 mm. The two vertical bars in the middle represent the corresponding first plane mirror and input coupling mirror. The spot size at the beam waist of the optical gain cavity is 35 μm.

[0096] According to the relationship between the wavelength of inverse Compton scattered light, the energy of the electron beam, and the wavelength of the incident light, the shortest wavelength of the inverse Compton scattered light in this embodiment is about 13.2 nm, the estimated average power is about 0.64 mW, the peak power is about 0.69 kW, and the scattered photon number rate within the 2% bandwidth is 10 10 / s, peak power density can reach 10MW / cm 2 .

[0097] For further reference, Figure 5 , Figure 5 A schematic diagram of the variation of the scattered photon number density with the scattering angle provided in an embodiment of the present invention shows that the photon scattering angle is generally smaller in the plane perpendicular to the polarization vector of the incident laser.

[0098] Therefore, it can be seen that the high-repetition-rate extreme ultraviolet radiation light source provided by the embodiment of the present invention has the advantages of high repetition rate, such as a room-temperature very high frequency photocathode microwave electron gun that can generate continuous picosecond electron beams, and a high-repetition-rate laser based on an oscillator and optical cavity amplification that can generate frequency-matched infrared laser pulses. The two undergo inverse Compton scattering to achieve high-repetition-rate EUV radiation. In addition, the electron beam spot and the laser spot are focused to tens of microns respectively through the accelerator's transverse focusing structure and the focusing effect of the optical cavity mirror, thereby improving the power density of the EUV radiation light. Furthermore, the overall device of the high-repetition-rate extreme ultraviolet radiation light source is about 2 meters long, which is relatively compact compared to large accelerators. In other words, the high-repetition-rate extreme ultraviolet radiation light source provided by the embodiment of the present invention has the advantages of high repetition rate, high power density, and compact structure.

[0099] Optionally, based on all the above embodiments of the present invention, an EUV lithography machine light source is further provided in another embodiment of the present invention. The EUV lithography machine light source includes the extreme ultraviolet radiation light source described in the above embodiments, and the EUV lithography machine light source has at least the same advantages as the extreme ultraviolet radiation light source.

[0100] The above is a detailed introduction to a high-repetition-rate extreme ultraviolet radiation light source and EUV lithography machine light source provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

[0101] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0102] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that the process, method, article, or apparatus comprising a series of elements inherent to the elements, or also including elements inherent to these processes, methods, articles, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0103] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high repetition rate extreme ultraviolet radiation source, characterized in that: The extreme ultraviolet radiation light source comprises: Ytterbium-doped femtosecond optical fiber master oscillator, used to generate the first infrared laser pulses with hundreds of megahertz milliwatt power; a chirped pulse amplification system, configured to process the first infrared laser pulse to generate a picosecond laser pulse with a watt-level power; a cryogenically cooled two-channel amplifier for processing the picosecond laser pulses to generate target laser pulses with an average power of more than kilowatts; Among them, a part of the target laser pulses is incident on a megawatt-class optical gain cavity to generate a second infrared laser pulse with an average power of megawatts; another part of the target laser pulses is incident on a room-temperature very high frequency photocathode microwave electron gun after frequency doubling and shaping, driving the room-temperature very high frequency photocathode microwave electron gun to generate a continuous picosecond electron beam with a repetition frequency of hundreds of megahertz; the continuous picosecond electron beam is incident on the megawatt-class optical gain cavity, and undergoes inverse Compton scattering with the second infrared laser pulse to generate extreme ultraviolet band radiation.

2. The extreme ultraviolet radiation light source according to claim 1, wherein: The chirped pulse amplification system comprises: a chirped body Bragg grating pulse stretcher, configured to stretch the first infrared laser pulse to generate a first transition laser pulse with a sub-milliwatt power; The preamplifier and the optical fiber amplifier are used to sequentially amplify the first transition laser pulse twice to generate a second transition laser pulse; A chirped body Bragg grating pulse compressor is used to compress the second transition laser pulse to generate the picosecond laser pulse.

3. The extreme ultraviolet radiation light source according to claim 1, wherein: The cryogenically cooled two-channel amplifier comprises: a first beam splitter, a first beam combiner, a cryogenically cooled Yb:YAG crystal, a first fiber-coupled laser diode and a second fiber-coupled laser diode; The first fiber-coupled laser diode corresponds to the first beam splitter; The second optical fiber coupled laser diode corresponds to the first beam combiner; The cryogenically cooled Yb:YAG crystal is located between the first beam splitter and the first beam combiner; The picosecond laser pulse is combined with the first beam splitter, the first beam combiner, the first fiber-coupled laser diode and the second fiber-coupled laser diode to enter the cryogenically cooled Yb:YAG crystal for energy storage and amplification, thereby generating the target laser pulse.

4. The extreme ultraviolet radiation light source according to claim 1, wherein: The megawatt-class optical gain cavity comprises an input coupling mirror, a first plane mirror and two off-axis parabolic mirrors; The target laser pulse is incident into the megawatt-class optical gain cavity through the input coupling mirror, and is stacked back and forth through the first plane mirror, the off-axis parabolic mirror and the input coupling mirror to generate the second infrared laser pulse.

5. The extreme ultraviolet radiation light source according to claim 1, wherein: The extreme ultraviolet radiation light source further includes: A frequency doubling system for performing frequency doubling processing on the target laser pulse incident on the room temperature very high frequency photocathode microwave electron gun; The shaping system is used to shape the target laser pulse processed by the frequency doubling system so as to be incident on the room temperature very high frequency photocathode microwave electron gun.

6. The extreme ultraviolet radiation light source according to claim 1, wherein: The extreme ultraviolet radiation light source further includes: The transverse focusing structure is used to focus the continuous picosecond electron beam.

7. The extreme ultraviolet radiation light source according to claim 1, wherein: The extreme ultraviolet radiation light source further includes: a control system and a power source; The control system is used to control the working state of the power source and the ytterbium-doped femtosecond optical master oscillator; The power source is used to provide microwave power to the room temperature very high frequency photocathode microwave electron gun and perform phase adjustment.

8. The extreme ultraviolet radiation light source according to claim 1, wherein: The extreme ultraviolet radiation light source further includes: A second plane mirror, a second beam splitter and a third plane mirror are sequentially positioned between the cryogenically cooled two-channel amplifier and the megawatt optical gain cavity.

9. The extreme ultraviolet radiation light source according to claim 8, characterized in that The extreme ultraviolet radiation light source further includes: A fourth plane mirror and a fifth plane mirror are located between the second beam splitter and the room temperature very high frequency photocathode microwave electron gun.

10. A light source for EUV lithography, characterized in that: The EUV lithography machine light source includes the extreme ultraviolet radiation light source according to any one of claims 1 to 9.

Images