Extreme ultraviolet light output method, device and equipment based on electrodeless pinch system

Abstract

The invention relates to the technical field of plasma EUV, in particular to an extreme ultraviolet light output method, device and equipment based on an electrodeless pinch system. The extreme ultraviolet light output method comprises the following steps: pre-ionizing lithium gas in an electrodeless pinch system to generate a first plasma group; completely ionizing the first plasma cluster to generate a second plasma cluster so as to generate an extreme ultraviolet beam; the light beam output assembly outputs extreme ultraviolet light beams, and the light beam output assembly outputting the extreme ultraviolet light beams is kept heated. The technical problems that the EUV radiation conversion efficiency is low, the spectral purity is poor, and the particle debris pollution of the tin target is serious are solved. The extreme ultraviolet light output device and the computer equipment have the same beneficial effects as the extreme ultraviolet light output method.

Description

[Technical field]

[0001] The present invention relates to the field of plasma EUV technology, and in particular to an extreme ultraviolet light output method, device and equipment based on an electrodeless pinch system. [Background technology]

[0002] Extreme Ultra Violet Lithography (EUVL) is a new generation of lithography technology using extreme ultraviolet (EUV) wavelengths. EUVL is currently the leading technology for printed circuits at 32nm nodes and below in high-volume manufacturing (HVM) environment fabs. In the process of implementing EUVL, the 13.5nm light radiation generated by the EUV source is strongly absorbed at this wavelength. The entire EUVL system must be carried out in a vacuum environment, and all optical collection elements use expensive Mo / Si multilayer mirrors with a reflectivity of about 70%.

[0003] EUVL technology faces many technical challenges in low-cost HVM. Among them, the difficulty of increasing the output power of EUV light source and controlling the cost of light source has attracted much attention. Therefore, the solution of using plasma to radiate EUV has been widely used. In the research process of improving the output power of plasma 13.5nm EUV light source, the main focus is on improving the conversion efficiency (CE) and reducing the contamination of light source debris.

[0004] At present, xenon (Xe), tin (Sn), and lithium (Li) are recognized as the three materials with the greatest potential to generate radiation targets in the 13.5nm band in HVM. Among them, Xe, as a rare gas, is the target material for the current commercial laser produced plasma (LPP) to generate EUV light sources. 10+ The ions radiate radiation in the 13.5 nm band, but their CE values ​​are low (about 0.8%-1.5%) and their spectral purity is poor.

[0005] Sn and Li are the most likely targets to produce mass production power levels. Among them, the radiation source of Sn target in the 13.5nm band is very extensive, mainly high-valent Sn ions (Sn 8+ —Sn 12+ ) transition, so its conversion efficiency is very high (about 3%-5%), and it is one of the most promising high-power EUV target materials, but the particle debris contamination of tin target is difficult to control. [Summary of the invention]

[0006] In order to solve the technical problems of low conversion efficiency of EUV radiation, poor spectral purity and serious particle debris contamination of tin target, the present invention provides an extreme ultraviolet light output method, device and equipment based on an electrodeless pinch system.

[0007] The solution to the technical problem of the present invention is to provide an extreme ultraviolet light output method based on an electrodeless pinch system, the method comprising:

[0008] Pre-ionizing lithium gas in the electrodeless pinch system to generate a first plasma cluster;

[0009] Completely ionizing the first plasma group to generate a second plasma group to produce an extreme ultraviolet light beam;

[0010] The beam output component outputs the extreme ultraviolet beam, and the beam output component outputting the extreme ultraviolet beam is kept heated.

[0011] Preferably, the preset temperature for maintaining heating is 400°C-750°C.

[0012] Preferably, the first plasma group includes lithium plasma with a valence state of +1, and the second plasma group includes lithium plasma with a valence state of +2 and +3.

[0013] Preferably, pre-ionizing lithium gas in the electrodeless pinch system to generate a first plasma group comprises:

[0014] Sublimating or melting and then gasifying a preset lithium target to generate the lithium gas and introduce it into the electrodeless pinch system;

[0015] The lithium gas introduced into the electrodeless pinch system is pre-ionized, and at least a portion of the lithium gas is converted into the first plasma group.

[0016] Preferably, completely ionizing the first plasma group to generate a second plasma group comprises:

[0017] Providing a preset electric pulse to the electrodeless pinch system to completely ionize the first plasma group;

[0018] The position where the first plasma group is located is irradiated with a preset pulse laser, and a second plasma group with a plasma temperature of 15eV-20eV is generated under the joint action of the preset electric pulse and the preset pulse laser to produce an extreme ultraviolet light beam.

[0019] Preferably, the preset electric pulse has a pulse width of 100ns-200ns, a peak power of 6kA-8kA, and a repetition frequency of 2.5kHz-3kHz.

[0020] Preferably, the preset pulse laser is a pulse laser generated after preprocessing, and the preprocessing includes shaping, beam expansion and / or focusing.

[0021] The present invention also provides an extreme ultraviolet light output device based on an electrodeless pinch system, which is used to implement the above-mentioned extreme ultraviolet light output method based on an electrodeless pinch system.

[0022] Preferably, the extreme ultraviolet light output device comprises a beam output component for outputting an extreme ultraviolet light beam, and the beam output component comprises:

[0023] A reflection and collection mirror, which is arranged correspondingly at the output end of the electrodeless pinch system, and reflects and collects the extreme ultraviolet light beam;

[0024] A heating element is arranged corresponding to the reflection and collection mirror, and is used for heating and maintaining the temperature of the reflection and collection mirror.

[0025] The present invention also provides a computer device, comprising a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to execute the computer program to implement the above-mentioned extreme ultraviolet light output method based on the electrodeless pinch system.

[0026] Compared with the prior art, the EUV light output method, device and equipment based on the electrodeless pinch system provided by the present invention have the following advantages:

[0027] 1. An embodiment of the present invention provides an extreme ultraviolet light output method based on an electrodeless pinch system, the method comprising: pre-ionizing lithium gas in the electrodeless pinch system to generate a first plasma group; completely ionizing the first plasma group to generate a second plasma group to produce an extreme ultraviolet light beam; a light beam output component outputs the extreme ultraviolet light beam, and the light beam output component that outputs the extreme ultraviolet light beam is kept heated.

[0028] It can be understood that the technical solution of the present invention selects lithium as the target material, uses lithium gas to obtain a first low-valent plasma group, and then completely ionizes it to obtain a second plasma group, and radiates 13.5nm extreme ultraviolet light. Through this design, the technical problems of low conversion efficiency of EUV radiation, poor spectral purity and serious particle debris contamination of tin target are solved.

[0029] It should be noted that, from the perspective of extreme ultraviolet radiation conversion efficiency, lithium is a new type of EUV target material. Lithium plasma based on LPP (laser produced plasma) technology radiates 13.5nm extreme ultraviolet light and can achieve a conversion efficiency of 2.5%, which is better than xenon target plasma EUV technology. Therefore, its conversion efficiency can meet the requirements of high-power EUV. From the perspective of spectral purity, lithium has a small atomic number and a simpler composition in the system - Li, Li + , Li 2+ , Li 3+ Therefore, the radiation spectrum purity of lithium target is purer than that of target materials with high atomic number (such as xenon target and tin target). Especially compared with the related technology of tin target, lithium target does not need spectral purity filter (Short Pass Filter, SPF) when used as medium, so the power loss is small, so higher output power can be obtained when lithium target is used as medium. As for the problem of particle debris contamination, since lithium has a small atomic number and a melting point of 180.5℃, the attached lithium metal can be removed by heating the beam output component, so that the lithium ions have less erosion on the optical collection elements in the beam output component and have self-cleaning function, which greatly improves the service life of the beam output component and reduces unnecessary costs.

[0030] 2. The EUV light output method based on the electrodeless pinch system provided in the embodiment of the present invention maintains the preset heating temperature at 400°C-750°C.

[0031] It can be understood that by keeping the beam output component that outputs the extreme ultraviolet light beam heated to a preset temperature and keeping the temperature of the beam output component within the above-mentioned preset temperature range, the lithium metal attached to the inner wall of the beam output component can be heated, so that the lithium metal can be vaporized or first melted and then vaporized to obtain lithium gas to achieve the reuse of the lithium target, thereby removing the deposited lithium metal and achieving the purpose of self-cleaning.

[0032] In addition, since lithium has a smaller atomic number, the first plasma group and the second plasma group have correspondingly smaller erosion on the beam output component. It should be noted that in EUVL, all optical collection elements use expensive Mo / Si multilayer reflectors. The beam output component of the present invention includes at least an optical collection element. Through this design, the service life of the beam output component can be improved and the cost can be further controlled.

[0033] 3. In the extreme ultraviolet light output method based on the electrodeless pinch system provided in an embodiment of the present invention, the first plasma group includes lithium plasma with a valence state of +1, and the second plasma group includes lithium plasma with a valence state of +2 and +3.

[0034] It should be noted that, in addition to most of the +1-valent lithium plasma, the first plasma group also contains at least a small amount of +2-valent lithium plasma, and there will not be only one type of ion in the plasma group; the second plasma group contains more +2-valent lithium plasma and a small amount of +3-valent lithium plasma.

[0035] Among them, lithium has a smaller atomic number and a simpler composition in the system - Li, Li + , Li 2+ , Li 3+ . Helium-like Li + (1s-2p transition), corresponding to a radiation wavelength of 19.9nm; hydrogen-like Li 2+ (1s-2p transition), corresponding to a radiation wavelength of 13.5nm; Li 2+ (1s-3p transition), corresponding to a radiation wavelength of 11.39nm; Li 3+ (1s-4p transition), radiating a wavelength of 10.8nm, among which the 1s-2p transition of hydrogen-like ions is the strongest, radiating an extreme ultraviolet beam of 13.5nm.

[0036] It can be understood that Li is generated by the collision between particles in the plasma. 2+ , Li 2+ The 1s-2p energy level transition radiates an extreme ultraviolet beam in the 13.5nm band; among them, the low-valence Li + Responsible for coordinating the transfer of energy.

[0037] 4. The extreme ultraviolet light output method based on the electrodeless pinch system provided in the embodiment of the present invention pre-ionizes the lithium gas in the electrodeless pinch system to generate the first plasma group, including: sublimating or melting and then gasifying a preset lithium target to generate lithium gas and introducing it into the electrodeless pinch system; pre-ionizing the lithium gas introduced into the electrodeless pinch system to convert at least part of the lithium gas into the first plasma group.

[0038] It can be understood that the process of pre-ionizing lithium gas to obtain the first plasma group is to prepare for the subsequent complete ionization of the first plasma group to obtain a second plasma group with a higher valence state. Compared with the scheme without pre-ionization, the actual CE value of the technical scheme of the present invention is higher.

[0039] It should be further explained that the technical solution of the present invention uses lithium with a lower atomic number as a target material, and its first ionization energy is relatively low, which is 520.2 kJ / mol, which is lower than the first ionization energies of the two common EUV target materials (among which, the first ionization energy of tin is 708.6 kJ / mol, and the first ionization energy of xenon is 1170.4 kJ / mol). Therefore, less energy is required to ionize the lithium target, and the lithium target is easier to ionize.

[0040] In addition, through this design, the electrons generated in the pre-ionization process can cooperate in the transfer of energy when the electric pulse is subsequently applied, so that the energy will be transferred into the plasma system in a faster manner.

[0041] 5. The EUV light output method based on the electrodeless pinch system provided in the embodiment of the present invention completely ionizes the first plasma group to generate the second plasma group, including: providing a preset electric pulse to the electrodeless pinch system to completely ionize the first plasma group; irradiating the position of the first plasma group with a preset pulse laser, and generating a second plasma group with a plasma temperature of 15eV-20eV under the combined action of the preset electric pulse and the preset pulse laser to produce an EUV light beam.

[0042] It should be noted that the preset electric pulse applies Lorentz force to the above-mentioned first plasma group, so that the low-valence lithium plasma is pinched until the radius reaches the minimum value. The position of the first plasma group is: the position where the plasma group with the minimum radius combines with the preset pulse laser. The plasma at this position has a minimum pinching radius, and its temperature and density reach maximum values.

[0043] It can be understood that the role of the preset pulse laser is to act on the first plasma group, that is, the low-valent lithium plasma, together with the preset electric pulse, to further shrink its size. Compared with using laser or electric pulse to compress plasma alone, this solution requires lower energy and is easier to implement technically; in addition, the addition of pulse laser is to utilize the high repetition frequency of laser to interact with plasma and thus increase the output power of extreme ultraviolet light.

[0044] Through the above steps, the stable absorption of pulsed laser and plasma cluster can be achieved to generate highly stable extreme ultraviolet light, which can save a lot of energy and improve the synchronization between plasma and pulsed laser.

[0045] 6. The EUV light output method based on the electrodeless pinch system provided in the embodiment of the present invention has a preset pulse width of the electric pulse of 100ns-200ns, a peak power of 6kA-8kA, and a repetition frequency of 2.5kHz-3kHz.

[0046] It can be understood that the pulse width, peak power and pulse repetition frequency of the preset electric pulse provided can make the main pulse power supply charge the capacitor while taking into account the cost of the extreme ultraviolet lithography technology.

[0047] 7. In the extreme ultraviolet light output method based on the electrodeless pinch system provided in the embodiment of the present invention, the preset pulse laser is a pulse laser generated after preprocessing, and the preprocessing includes shaping, beam expansion and / or focusing.

[0048] It should be noted that the preprocessing of the initial pulsed laser in the present invention includes at least one of shaping, beam expansion and focusing to obtain a light spot with high power and uniform energy distribution. Such a light beam can react quickly after interacting with the plasma group to produce stable extreme ultraviolet radiation.

[0049] It can be understood that the use of laser to act on low-valent lithium plasma does not have high requirements on parameters such as laser peak power, pulse width and repetition frequency. Therefore, there are many types of lasers to choose from, and the main function is to increase the repetition frequency of extreme ultraviolet radiation.

[0050] 8. The embodiment of the present invention further provides an EUV light output device based on an electrodeless pinch system, which is used to implement the above-mentioned EUV light output method based on an electrodeless pinch system.

[0051] The extreme ultraviolet light output device includes a beam output component for outputting an extreme ultraviolet light beam, and the beam output component includes: a reflection and collection mirror, which is correspondingly arranged at the output end of the electrodeless pinch system, and the reflection and collection mirror reflects and collects the extreme ultraviolet light beam; a heating element, which is arranged corresponding to the reflection and collection mirror, and the heating element is used to heat and maintain the temperature of the reflection and collection mirror.

[0052] The extreme ultraviolet light output device has the same beneficial effects as the above-mentioned extreme ultraviolet light output method, which will not be described in detail here.

[0053] 9. An embodiment of the present invention further provides a computer device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to execute the computer program to implement the above-mentioned extreme ultraviolet light output method based on the electrodeless pinch system.

[0054] The computer device has the same beneficial effects as the above-mentioned extreme ultraviolet light output method, which will not be described in detail here.

Brief Description of the Drawings

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0056] Figure 1 It is a schematic flow chart of an extreme ultraviolet light output method based on an electrodeless pinch system provided in the first embodiment of the present invention.

[0057] Figure 2 It is a flow chart of step S1 in an EUV light output method based on an electrodeless pinch system provided in the first embodiment of the present invention.

[0058] Figure 3 It is a flow chart of step S2 in an EUV light output method based on an electrodeless pinch system provided in the first embodiment of the present invention.

[0059] Figure 4 It is a schematic diagram of the framework of an extreme ultraviolet light output device based on an electrodeless pinch system provided by the second embodiment of the present invention.

[0060] Figure 5 It is a partial structural schematic diagram of an electrodeless pinch system and a light source generating component in an extreme ultraviolet light output device based on an electrodeless pinch system provided by a second embodiment of the present invention.

[0061] Figure 6 It is a schematic diagram of the framework of a computer device provided by the third embodiment of the present invention.

[0062] Description of the accompanying drawings:

[0063] 1. Extreme ultraviolet light output device; 11. Electrodeless pinch system; 12. Light beam output assembly; 121. Reflection collection mirror; 122. Heating element; 13. Light source generation assembly;

[0064] 2. discharge chamber; 21. first magnetic core; 22. second magnetic core; 23. center hole; 24. through hole; 25. plasma ring; 26. preset position; 27. pulsed laser; 28. EUV radiation;

[0065] 3. Computer equipment; 31. Memory; 311. Computer program; 32. Processor. [Specific implementation method]

[0066] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0067] In the embodiments provided by the present invention, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0068] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. Those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required for the present invention.

[0069] In various embodiments of the present invention, it should be understood that the size of the serial numbers of the above-mentioned processes does not mean the necessary order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0070] The flow chart and block diagram in the accompanying drawings of the present invention illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which is determined based on the functions involved. It should be particularly noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs a specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0071] EUVL (extreme ultraviolet lithography) technology has many technical challenges in low-cost HVM (high volume manufacturing), among which the difficulties of increasing the output power of EUVL and controlling the cost of the light source have attracted much attention.

[0072] Specifically, the present invention uses lithium as a target material, and ionizes lithium metal in an electrodeless pinch system to obtain an initial low-valent lithium plasma. Subsequently, the low-valent lithium plasma generates a completely ionized high-valent lithium plasma under the combined action of a pulsed laser and an electric pulse, and at the same time, radiates a 13.5nm extreme ultraviolet light beam. This solution can reduce the power requirements for pulsed lasers and electric pulses while obtaining a higher CE (conversion efficiency) value, wherein the beam output component of the light source collection part includes a reflective collection mirror and a heating element, and the heating element realizes the self-cleaning function of the reflective collection mirror, thereby extending the service life of the reflective collection mirror.

[0073] In EUVL, cost control is mainly reflected in the simple structure of the light source and the long service life of the core components in the light source (such as the reflective collection mirror in the optical collection element). For core components such as the reflective collection mirror, if a layer of metal film is attached to the mirror, the reflectivity of the reflective collection mirror will be reduced, and even its service life will be reduced. As we all know, the optical collection elements of extreme ultraviolet light are very expensive. Therefore, based on cost considerations, this scheme heats the reflective collection mirror so that the lithium metal deposited on the mirror surface of the reflective collection mirror is liquefied or even vaporized and falls off, thereby realizing the self-cleaning function.

[0074] The technical solutions involved in the present invention are described below.

[0075] See also Figure 1 The first embodiment of the present invention provides an extreme ultraviolet light output method based on an electrodeless pinch system, the method comprising:

[0076] S1: pre-ionizing lithium gas in an electrodeless pinch system to generate a first plasma cluster;

[0077] S2: completely ionizing the first plasma group to generate a second plasma group to produce an extreme ultraviolet beam;

[0078] S3: The beam output component outputs an extreme ultraviolet beam, and the beam output component outputting the extreme ultraviolet beam is kept heated.

[0079] It can be understood that the technical solution of the present invention selects lithium as the target material, uses lithium gas to obtain a first low-valent plasma group, and then completely ionizes it to obtain a second plasma group, and radiates 13.5nm extreme ultraviolet light. Through this design, the technical problems of low conversion efficiency of EUV radiation, poor spectral purity and serious particle debris contamination of tin target are solved.

[0080] First, from the perspective of the conversion efficiency (CE) of EUV radiation, lithium is a new type of EUV target material. The 13.5nm EUV light source radiated by lithium plasma based on laser produced plasma technology (LPP) can achieve a conversion efficiency of 2.5%, which is better than the plasma EUV technology of xenon target. Therefore, its conversion efficiency can meet the requirements of high-power EUV; and the 13.5nm EUV light source radiated by laser-assisted discharge technology (Laser-assisted Discharge Plasma, LDP for short) can achieve a conversion efficiency of about 2.3%-3%, which is second only to tin and is also suitable for applications with high EUV power levels.

[0081] Secondly, from the perspective of spectral purity, lithium has a small atomic number and a relatively simple composition in the system—Li, Li + , Li 2+ , Li 3+ Therefore, the radiation spectrum purity of the lithium target is purer than that of the target with a high atomic number (such as xenon target and tin target). This is because the out-of-band (OOB) radiation of lithium is smaller. OOB radiation refers to the components of the light source with a wavelength other than 13.5nm during extreme ultraviolet lithography exposure.

[0082] In addition, especially compared with the related technology of tin target, lithium target does not need to use spectral purity filter (Short Pass Filter, SPF) when used as medium, so the power loss is small, so that higher output power can be obtained when lithium target is used as medium.

[0083] It should be noted that since the spectrum of lithium is relatively simple, the ideal 13.5nm radiation band can be picked out from the spectrum without the need for spectral purity filtering, which can reduce energy loss in the SPF process and thus obtain greater EUV output power.

[0084] Furthermore, as for the problem of particle debris contamination, since lithium has a small atomic number and a melting point of 180.5°C, the attached lithium metal can be removed by keeping the beam output component heated, so that the lithium ions have less erosion on the optical collection elements in the beam output component and have a self-cleaning function, which greatly improves the service life of the beam output component and reduces unnecessary costs.

[0085] Among them, in the technical solution of the present invention, lithium metal is heated to convert it from solid to gas, and then introduced into the electrodeless pinching system for electric pulse, ionization, pinching and other processes. Under ideal conditions, the electrodeless pinching system is filled with working target material (lithium gas), and the beam output component is also exposed to the lithium gas environment. When the temperature in the electrodeless pinching system changes, lithium metal may be deposited on the beam output component.

[0086] It should be further explained that there are two types of heating and vaporizing lithium metal. The first is the conventional solid-liquid-gas state, that is, lithium metal is first melted and then vaporized to obtain lithium gas; the second is the process directly from solid to gas (sublimation); because both types of vaporization may exist under actual working conditions, the technical solution involved in the present invention does not need to limit the type of physical state change, and the above two physical state changes can solve the technical problem of serious particle debris pollution.

[0087] See also Figure 2 As an optional embodiment, pre-ionizing lithium gas in an electrodeless pinch system to generate a first plasma group includes:

[0088] S11: sublimating or melting and then gasifying a preset lithium target to generate lithium gas and introduce it into the electrodeless pinch system;

[0089] S12: pre-ionizing the lithium gas introduced into the electrodeless pinch system, and converting at least a portion of the lithium gas into a first plasma group.

[0090] It should be noted that the preset lithium target is specifically lithium metal. In the technical solution of the present invention, in order to obtain lithium gas, the lithium metal is sublimated or melted and then gasified, and then the lithium gas is introduced into the electrodeless pinch system at a certain flow rate through a ventilation pipe, wherein the gas flow rate can be set according to actual needs, and the present invention is not limited to it. Any modifications, equivalent substitutions and improvements made within the principles of the present invention should be included in the protection scope of the present invention.

[0091] As a preferred implementation of the first embodiment of the present invention, lithium metal is sublimated or melted and then gasified to obtain lithium gas, which is achieved by a lithium metal gasification device located at the front end of the electrodeless pinch system. Specifically, lithium metal with the advantage of "self-cleaning" is used, and its atomic number is small, and its melting point is low (180.5°C), which is easy to achieve. Lithium metal can also be gasified into lithium gas by heating. In contrast, the conventional solution is to directly use pulsed laser to bombard metal target (such as tin target), and achieve gasification and ionization in a very short time. In this process, serious debris pollution will be generated, which will have a huge impact on the service life of the beam output component.

[0092] Specifically, the steps of the method involved in the present invention are implemented in an electrodeless pinch system for ionizing lithium gas into lithium plasma, and in the system, a pre-current and a main current are generated by a device similar to a "magnetic switch", and the electrodeless pinch system is charged by an energy storage device (such as a capacitor, an inductor, etc.) at the front end. The capacitor generates a leakage current during the charging process, and this leakage current directly acts on the lithium target to preliminarily ionize it to obtain initial lithium ions, thereby forming a first plasma group, which includes low-valent lithium plasma. It can be understood that the process of pre-ionizing lithium gas to obtain the first plasma group is to prepare for the subsequent complete ionization of the first plasma group to obtain a second plasma group with a higher valence. Compared with the scheme without pre-ionization, the actual CE value of the technical scheme of the present invention is higher.

[0093] It should be further explained that the technical solution of the present invention uses lithium with a lower atomic number as a target material. The first ionization energy of the lithium target is relatively low, which is 520.2 kJ / mol, which is lower than the first ionization energies of the two common EUV target materials. Among them, the first ionization energy of tin is 708.6 kJ / mol, and the first ionization energy of xenon is 1170.4 kJ / mol. Therefore, less energy is required to ionize the lithium target. Compared with tin target and xenon target, lithium target is easier to ionize.

[0094] In addition, through this design, the electrons generated in the pre-ionization process can cooperate in the transfer of energy when the electric pulse is subsequently applied, so that the energy will be transferred into the plasma system in a faster manner.

[0095] For details, please refer to Figure 3 , completely ionizing the first plasma group to generate a second plasma group includes:

[0096] S21: providing a preset electric pulse to the electrodeless pinch system to completely ionize the first plasma group;

[0097] S22: irradiate the position of the first plasma group with a preset pulse laser, and generate a second plasma group with a plasma temperature of 15eV-20eV under the combined action of the preset electric pulse and the preset pulse laser to produce an extreme ultraviolet light beam.

[0098] It should be noted that the preset electric pulse applies Lorentz force to the above-mentioned first plasma group, so that the low-valence lithium plasma is pinched until the radius reaches the minimum value. The position of the first plasma group is: the position where the plasma group with the minimum radius combines with the preset pulse laser. The plasma at this position has a minimum pinching radius, and its temperature and density reach maximum values.

[0099] It can be understood that the role of the preset pulse laser is to act on the first plasma group, that is, the low-valent lithium plasma, together with the preset electric pulse, to further shrink its size. Compared with using laser or electric pulse to compress plasma alone, this solution requires lower energy and is easier to implement technically; in addition, the addition of pulse laser is to utilize the high repetition frequency of laser to interact with plasma and thus increase the output power of extreme ultraviolet light.

[0100] In particular, for step S22, when lithium is used as a target material with a low atomic number, the required plasma temperature is 15eV-20eV when achieving optimal EUV radiation, where eV (electron volt) is a unit of energy, representing an electron (charged with 1.6×10 -19 The kinetic energy gained by a negative charge (C) after being accelerated by a potential difference of 1 volt can be converted to the common energy unit (joule): 1eV = 1.6×10 -19 J.

[0101] When EUV radiation is achieved, the plasma density in the electrodeless pinch system is 8×10 15 cm -3 -3×10 19 cm -3 When the plasma temperature in the electrodeless pinch system is 15eV-20eV, that is, when the EUV optimal radiation is achieved, the second plasma group mainly contains Li 2+ (i.e. +2-valent lithium plasma), the plasma density is on the order of 10 18 cm -3 -10 19 cm -3 .

[0102] Optionally, the laser single pulse energy of the pulse laser is 0.25J-0.5J, the laser repetition frequency is 10Hz, the pulse width is 5ns-20ns, and the laser power density is 1×10 9 W / cm 2 -2.5×10 12 W / cm 2 , where when the laser power density is 8×10 10 W / cm 2 -1×10 11 W / cm 2 Within the range of , EUV output efficiency is higher.

[0103] Furthermore, the repetition frequency of the extreme ultraviolet radiation can be controlled by controlling the delay time between the preset pulse laser and the electric pulse. For controlling the repetition frequency by controlling the delay time, the repetition frequency of the final extreme ultraviolet light can be increased by wavelength division multiplexing the pulse laser in space in the LPP scheme to generate a time difference (i.e., delay time).

[0104] In the technical solution of the present invention, pulsed laser and electric pulse are used to act on the first plasma group formed by low-valent lithium plasma with a certain time difference, and then a second plasma group formed by the convergence of high-valent lithium plasma is obtained, which then radiates extreme ultraviolet light; when the electric pulse acts on the first plasma group, the Z-pinch pinch effect generated compresses the low-valent lithium plasma to produce high-valent lithium plasma, and when the volume of the plasma is compressed to the minimum, it begins to radiate extreme ultraviolet light. Since the magnetic pressure and thermal pressure are a dynamic equilibrium process, the volume of the plasma will also change to a certain extent, and the extreme ultraviolet radiation generated will also change with the change of the plasma volume.

[0105] Therefore, when the electric pulse acts on the plasma, adding the pulsed laser to achieve a composite effect can make the volume of the plasma in dynamic equilibrium, and the speed of its volume change will be accelerated, thereby increasing the repetition frequency of extreme ultraviolet light radiation. Compared with applying the pulsed laser and electric pulse to the initial plasma with a certain delay time, increasing the repetition frequency of the electric pulse alone is technically difficult and costly.

[0106] Through the above steps, the stable absorption of pulsed laser and plasma cluster can be achieved to generate highly stable EUV radiation, which can save a lot of energy and thus improve the synchronization between plasma and pulsed laser. In addition, through this design, the electrons generated in the pre-ionization process will cooperate in the transfer of energy under the action of electric pulses, so that the energy can be transmitted into the plasma system in a faster manner.

[0107] The preset temperature for heating the beam output component that outputs the extreme ultraviolet beam is 400°C-750°C.

[0108] It should be noted that the preset temperature for heating the beam output component can be in the range of 400°C to 750°C (including 400°C and 750°C). The beam output component is heated and maintained at 400°C or above to vaporize the lithium metal to ensure the working environment in the electrodeless pinch system. The density of the lithium gas obtained by vaporization in a suitable working environment is positively distributed with temperature. As the temperature rises, the density increases, and the intensity of EUV radiated will also increase accordingly.

[0109] Specifically, the first embodiment of the present invention takes the preset temperature of 400°C for the light beam output assembly to be kept heated as an example; the light beam output assembly is kept heated to 400°C to remove the deposited lithium metal, so that it is converted into lithium gas and returned to the electrodeless pinch system. On the one hand, due to the small atomic number of lithium, the erosion of the Mo / Si multilayer reflector by lithium ions is relatively small, which improves the use efficiency and service life of the light beam output assembly; on the other hand, the deposited lithium metal is re-gasified (including sublimation or melting first and then gasification) and then returned to the electrodeless pinch system for reuse, which improves the utilization rate of the target material.

[0110] It can be understood that the present invention is only described by giving one embodiment, and any modifications, equivalent substitutions and improvements made within the principles of the present invention should be included in the protection scope of the present invention.

[0111] It can be further understood that by keeping the beam output component that outputs the extreme ultraviolet light beam heated to a preset temperature and keeping the temperature of the beam output component within the above-mentioned preset temperature range, the lithium metal attached to the inner wall of the beam output component can be heated, so that the lithium metal can be vaporized or first melted and then vaporized to obtain lithium gas to achieve the reuse of the lithium target, thereby removing the deposited lithium metal and achieving the purpose of self-cleaning.

[0112] In addition, since lithium has a smaller atomic number, the first plasma group and the second plasma group have correspondingly smaller erosion on the beam output component. It should be noted that in EUVL, all optical collection elements use expensive Mo / Si multilayer reflectors. The beam output component of the present invention includes at least an optical collection element. Through this design, the service life of the beam output component can be improved and the cost can be further controlled.

[0113] Further, the first plasma group includes lithium plasma with a valence state of +1, and the second plasma group includes lithium plasma with a valence state of +2 and +3.

[0114] It should be noted that, in addition to most of the +1-valent lithium plasma, the first plasma group also contains at least a small amount of +2-valent lithium plasma, and there will not be only one type of ion in the plasma group; the second plasma group contains more +2-valent lithium plasma and a small amount of +3-valent lithium plasma.

[0115] Among them, Li has a smaller atomic number and a simpler composition in the system: Li, Li + , Li 2+ , Li 3+ . Helium-like Li + (1s-2p transition), corresponding to a radiation wavelength of 19.9nm; hydrogen-like Li 2+(1s-2p transition), corresponding to a radiation wavelength of 13.5nm; Li 2+ (1s-3p transition), corresponding to a radiation wavelength of 11.39nm; Li 3+ (1s-4p transition), radiating at a wavelength of 10.8nm, among which the hydrogen-like ion Li 2+ The 1s-2p transition is the strongest and can radiate an extreme ultraviolet beam of 13.5nm.

[0116] It can be understood that Li is generated by the collision between particles in the plasma. 2+ , Li 2+ The 1s-2p energy level transition radiates an extreme ultraviolet beam in the 13.5nm band; among them, the low-valence Li + Responsible for coordinating the transfer of energy.

[0117] As another optional implementation, the pulse width of the preset electric pulse is 100ns-200ns, the peak power is 6kA-8kA, and the repetition frequency is 2.5kHz-3kHz.

[0118] It can be understood that the relevant parameters of the preset electric pulse are calculated based on the ionization energy of lithium metal and the plasma temperature required to radiate 13.5nm extreme ultraviolet light, specifically including the complete ionization of the first plasma group, Li 2+ The energy input corresponding to processes such as the energy level transition of ions is required to achieve the optimal lithium plasma EUV radiation efficiency.

[0119] It should be noted that the first plasma cluster can produce a Z-pinch pinching effect under the action of the main current pulse to further compress the size of the plasma cluster; it can be understood that the preset electric pulse provided, its pulse width, peak power and electric pulse repetition frequency can enable the main pulse power supply, that is, the electric pulse power supply, to charge the capacitor while taking into account the EUVL cost.

[0120] As another optional implementation, the preset pulse laser is a pulse laser generated after preprocessing, and the preprocessing includes shaping, beam expansion and / or focusing.

[0121] It should be noted that the pre-processing of the initial pulsed laser in the present invention includes at least one of shaping, beam expansion, and focusing, so as to obtain a light spot with high power and uniform energy distribution. Such a light beam can react quickly after interacting with the plasma group to produce stable extreme ultraviolet radiation. Since the spectrum of lithium is relatively simple, the ideal 13.5nm radiation band can be selected from the spectrum diagram, so there is no need to perform spectral purity filtering, which can reduce energy loss in the SPF process, thereby obtaining a larger EUV output power.

[0122] It can be understood that the use of laser to act on the low-valent lithium plasma in the first plasma group does not have high requirements on parameters such as laser peak power, pulse width and repetition frequency. Therefore, there are many types of lasers to choose from, and the main function is to increase the repetition frequency of EUV radiation.

[0123] Optionally, the light source of the preset pulse laser is an excimer laser, a fiber laser, a CO 2 Any of laser and solid-state laser.

[0124] Optionally, when the light source of the preset pulse laser is a solid laser, the solid laser may specifically be a Nd:YAG solid laser, wherein the wavelength band of the Nd:YAG solid laser includes but is not limited to 355 nm, 532 nm and 1064 nm.

[0125] See also Figure 4 The second embodiment of the present invention provides an EUV light output device 1 based on an electrodeless pinch system, which is used to implement the above-mentioned EUV light output method based on an electrodeless pinch system.

[0126] Furthermore, the extreme ultraviolet light output device 1 includes an electrodeless pinch system 11 and a beam output component 12 for outputting an extreme ultraviolet light beam, and the beam output component 12 includes:

[0127] A reflection and collection mirror 121 is correspondingly arranged at the output end of the electrodeless pinch system 11, and the reflection and collection mirror 121 reflects and collects the extreme ultraviolet light beam;

[0128] The heating element 122 is disposed corresponding to the reflection collection mirror 121 , and is used for heating and maintaining the temperature of the reflection collection mirror 121 .

[0129] It can be understood that the electrodeless pinch system 11 is used to obtain the second plasma group and generate the extreme ultraviolet beam. When achieving the best EUV radiation, the plasma temperature of the second plasma group is 15eV-20eV and the plasma density is on the order of 10 18 cm -3 -10 19 cm -3 ; The reflecting and collecting mirror 121 is arranged at the output end of the electrodeless pinching system 11 to reflect and collect the extreme ultraviolet light beam, and the heating element 122 is arranged corresponding to the reflecting and collecting mirror 121 to heat the reflecting and collecting mirror 121.

[0130] It should be noted that in the specific implementation of the second embodiment of the present invention, the beam output component 12 is concave. Since it is used for the extreme ultraviolet light band (13.5nm), the surface of the reflective collection mirror 121 needs to be coated with a multi-layer Mo / Si reflective film.

[0131] It can be understood that by controlling the reflective collection mirror 121 to maintain the preset heating temperature of 400°C-750°C (the first embodiment of the present invention takes the preset temperature of 400°C as an example), the deposited lithium metal is removed and converted into lithium gas which is returned to the electrodeless pinch system 11.

[0132] Specifically, the heating element 122 heats the temperature of the reflection and collection mirror 121 to a preset temperature and continuously maintains it within the temperature range. The motivation for heating the reflection and collection mirror 121 to the preset temperature has the following two considerations: on the one hand, due to the small atomic number of lithium, the erosion of the reflection and collection mirror 121 (Mo / Si multilayer reflection mirror) by lithium ions is relatively small, which improves the use efficiency and service life of the beam output component 12; on the other hand, the deposited lithium metal is re-vaporized (including sublimation or melting and then vaporization) and returned to the electrodeless pinch system 11 for reuse, thereby improving the utilization rate of the target material.

[0133] The technical solution of the present invention uses electromagnetic induction to generate high-voltage electric pulses. Through this design, compared with the structure with electrodes, debris contamination is greatly reduced, thereby increasing the service life of the reflective collection mirror 121 and further controlling costs.

[0134] For easier understanding, see Figure 4 and Figure 5 The present invention focuses on explaining the electrodeless pinch system 11. The electrodeless pinch system 11 includes a discharge chamber 2. The ionizable medium is lithium. The discharge chamber 2 is used to discharge the lithium and generate low-valent lithium plasma to form a lithium plasma group. A first magnetic core 21 and a second magnetic core 22 are arranged in the discharge chamber 2. The second magnetic core 22 has a high impedance and allows a small amount of leakage current to flow through. It is used to decompose the ionizable medium (lithium) into low-valent lithium plasma and maintain its plasma state, thereby forming pre-ionization.

[0135] The conversion rate of plasma EUV can be improved by pre-ionizing the ionizable medium Li. During the capacitor charging process, a small amount of leakage current in the circuit is used to decompose the ionizable medium (lithium) into low-valent lithium plasma and maintain its plasma state, which can effectively improve the conversion efficiency of plasma; in addition, the electrons generated in the pre-ionization process will cooperate with the transfer of energy under the action of the electric pulse, so that the energy is transferred into the plasma system in a faster way.

[0136] During this process, lithium is ionized and generates low-valent lithium plasma. The first magnetic core 21 provides a magnetic field environment for the low-valent lithium plasma to pinch the low-valent lithium plasma to a preset position 26 .

[0137] Specifically, the Lorentz force generated by the magnetic field and the electric field generated by the first magnetic core 21 is greater than the thermal pressure of the plasma, causing the plasma to pinch inward. This process increases the probability of collision between electrons and ions and between ions, causing the temperature inside the plasma to rise. When the magnetic pressure is balanced with the thermal pressure, at the preset position 26 in the center hole 23, the pinch radius of the plasma at the preset position 26 can reach a minimum value, and the temperature and density reach a maximum value. A center hole 23 is provided on the first magnetic core 21, the first magnetic core 21 is provided around the center hole 23, the second magnetic core 22 is located on a side of the first magnetic core 21 away from the center hole 23, and at least one through hole 24 is provided between the first magnetic core 21 and the second magnetic core 22. The ionizable medium Li forms a plasma ring 25 under the action of the first magnetic core 21 and the second magnetic core 22, and the plasma ring 25 passes through the through hole 24 and the center hole 23 respectively.

[0138] Please continue reading Figure 4 and Figure 5 In the extreme ultraviolet light output device 1 provided in the second embodiment of the present invention, the output end of the light source generating component 13 is coaxially arranged with the central hole 23, and the pulse laser 27 emitted by the light source generating component 13 is injected into the receiving end of the central hole 23 and reacts with the plasma group of the central hole 23 to generate EUV radiation 28 which is emitted from the emitting end.

[0139] It should be noted that the light source generating assembly 13 is coaxially arranged with the center hole 23, so that the output end of the light source generating assembly 13 is aligned with the preset position 26 in the electrodeless pinch system 11, so that the pulse laser 27 generated by the light source generating assembly 13 can generate EUV radiation 28 by bombarding the plasma group at the preset position 26.

[0140] Specifically, the working principle of the electrodeless pinch system 11 is as follows: the DC power supply stores the charge in the capacitor through the modulation circuit, and the leakage current generated in this process ionizes the lithium into +1 ions. When the magnetic switch is saturated, the energy pulse supplies energy to the plasma in the system in a mutual inductance manner, and uses its own magnetic field to continuously compress the plasma to radiate EUV. Among them, the 13.5nm extreme ultraviolet radiation light generated by lithium gas discharge belongs to Li 2+ 1s-2p energy level transition.

[0141] It should be noted that the electrodeless pinch system 11 can squeeze the plasma to a certain spatial position, and the plasma at this time has the characteristics of small radius and high density, which is conducive to improving the synchronization between the plasma and the pulse laser 27 and achieving stable output of the EUV light source. At the same time, the pre-ionization process of the electrodeless pinch system 11 in this embodiment also effectively improves the conversion efficiency of the plasma from a low valence state to a high valence state; in addition, the electrons generated in this process will also cooperate in the transfer of energy under the action of the electric pulse, so that the energy is transmitted into the plasma system in a faster manner.

[0142] See also Figure 6 The third embodiment of the present invention provides a computer device 3, including a memory 31 and a processor 32, the memory 31 is used to store a computer program 311, and the processor 32 is used to execute the computer program 311 to implement the above-mentioned extreme ultraviolet light output method based on the electrodeless pinch system.

[0143] It can be understood that when the computer device 3 in the third embodiment of the present invention is running, when the processor 32 executes the computer program 311, the extreme ultraviolet light output method described in the first embodiment can be implemented.

[0144] It should be noted that the computer device 3 provided in the third embodiment of the present invention has the same beneficial effects as the above-mentioned extreme ultraviolet light output method based on the electrodeless pinch system.

[0145] Specifically, the computer device 3 can be a computer device used in the field of plasma EUV technology, including but not limited to the control of the delay time between the pulse laser and the electric pulse, the heating control of the reflective collection mirror, and the control of the amount of gas introduced into the electrodeless pinch system for gasifying lithium metal into gas. It will not be elaborated here. In theory, all the steps involved in the technical solution of the present invention can be realized through the control of the computer device 3, and the relevant parameters involved can also be adjusted accordingly through the computer device 3, where the relevant parameters include but are not limited to maintaining the preset temperature of the heating, as well as the pulse width, peak power, repetition frequency, etc. of the pulse laser and electric pulse.

[0146] Compared with the prior art, the EUV light output method, device and equipment based on the electrodeless pinch system provided by the present invention have the following advantages:

[0147] 1. An embodiment of the present invention provides an extreme ultraviolet light output method based on an electrodeless pinch system, the method comprising: pre-ionizing lithium gas in the electrodeless pinch system to generate a first plasma group; completely ionizing the first plasma group to generate a second plasma group to produce an extreme ultraviolet light beam; a light beam output component outputs the extreme ultraviolet light beam, and the light beam output component that outputs the extreme ultraviolet light beam is kept heated.

[0148] It can be understood that the technical solution of the present invention selects lithium as the target material, uses lithium gas to obtain a first low-valent plasma group, and then completely ionizes it to obtain a second plasma group, and radiates 13.5nm extreme ultraviolet light. Through this design, the technical problems of low conversion efficiency of EUV radiation, poor spectral purity and serious particle debris contamination of tin target are solved.

[0149] It should be noted that, from the perspective of extreme ultraviolet radiation conversion efficiency, lithium is a new type of EUV target material. Lithium plasma based on LPP (laser produced plasma) technology radiates 13.5nm extreme ultraviolet light and can achieve a conversion efficiency of 2.5%, which is better than xenon target plasma EUV technology. Therefore, its conversion efficiency can meet the requirements of high-power EUV. From the perspective of spectral purity, lithium has a small atomic number and a simpler composition in the system - Li, Li + , Li 2+ , Li 3+ Therefore, the radiation spectrum purity of lithium target is purer than that of target materials with high atomic number (such as xenon target and tin target). Especially compared with the related technology of tin target, lithium target does not need spectral purity filter (Short Pass Filter, SPF) when used as medium, so the power loss is small, so higher output power can be obtained when lithium target is used as medium. As for the problem of particle debris contamination, since lithium has a small atomic number and a melting point of 180.5℃, the attached lithium metal can be removed by heating the beam output component, so that the lithium ions have less erosion on the optical collection elements in the beam output component and have self-cleaning function, which greatly improves the service life of the beam output component and reduces unnecessary costs.

[0150] 2. The EUV light output method based on the electrodeless pinch system provided in the embodiment of the present invention maintains the preset heating temperature at 400°C-750°C.

[0151] It can be understood that by keeping the beam output component that outputs the extreme ultraviolet light beam heated to a preset temperature and keeping the temperature of the beam output component within the above-mentioned preset temperature range, the lithium metal attached to the inner wall of the beam output component can be heated, so that the lithium metal can be vaporized or first melted and then vaporized to obtain lithium gas to achieve the reuse of the lithium target, thereby removing the deposited lithium metal and achieving the purpose of self-cleaning.

[0152] In addition, since lithium has a smaller atomic number, the first plasma group and the second plasma group have correspondingly smaller erosion on the beam output component. It should be noted that in EUVL, all optical collection elements use expensive Mo / Si multilayer reflectors. The beam output component of the present invention includes at least an optical collection element. Through this design, the service life of the beam output component can be improved and the cost can be further controlled.

[0153] 3. In the extreme ultraviolet light output method based on the electrodeless pinch system provided in an embodiment of the present invention, the first plasma group includes lithium plasma with a valence state of +1, and the second plasma group includes lithium plasma with a valence state of +2 and +3.

[0154] It should be noted that, in addition to most of the +1-valent lithium plasma, the first plasma group also contains at least a small amount of +2-valent lithium plasma, and there will not be only one type of ion in the plasma group; the second plasma group contains more +2-valent lithium plasma and a small amount of +3-valent lithium plasma.

[0155] Among them, lithium has a smaller atomic number and a simpler composition in the system - Li, Li + , Li 2+ , Li 3+ . Helium-like Li + (1s-2p transition), corresponding to a radiation wavelength of 19.9nm; hydrogen-like Li 2+ (1s-2p transition), corresponding to a radiation wavelength of 13.5nm; Li 2+ (1s-3p transition), corresponding to a radiation wavelength of 11.39nm; Li 3+ (1s-4p transition), radiating a wavelength of 10.8nm, among which the 1s-2p transition of hydrogen-like ions is the strongest, radiating an extreme ultraviolet beam of 13.5nm.

[0156] It can be understood that Li is generated by the collision between particles in the plasma. 2+ , Li 2+ The 1s-2p energy level transition radiates an extreme ultraviolet beam in the 13.5nm band; among them, the low-valence Li + Responsible for coordinating the transfer of energy.

[0157] 4. The extreme ultraviolet light output method based on the electrodeless pinch system provided in the embodiment of the present invention pre-ionizes the lithium gas in the electrodeless pinch system to generate the first plasma group, including: sublimating or melting and then gasifying a preset lithium target to generate lithium gas and introducing it into the electrodeless pinch system; pre-ionizing the lithium gas introduced into the electrodeless pinch system to convert at least part of the lithium gas into the first plasma group.

[0158] It can be understood that the process of pre-ionizing lithium gas to obtain the first plasma group is to prepare for the subsequent complete ionization of the first plasma group to obtain a second plasma group with a higher valence state. Compared with the scheme without pre-ionization, the actual CE value of the technical scheme of the present invention is higher.

[0159] It should be further explained that the technical solution of the present invention uses lithium with a lower atomic number as a target material, and its first ionization energy is relatively low, which is 520.2 kJ / mol, which is lower than the first ionization energies of the two common EUV target materials (among which, the first ionization energy of tin is 708.6 kJ / mol, and the first ionization energy of xenon is 1170.4 kJ / mol). Therefore, less energy is required to ionize the lithium target, and the lithium target is easier to ionize.

[0160] In addition, through this design, the electrons generated in the pre-ionization process can cooperate in the transfer of energy when the electric pulse is subsequently applied, so that the energy will be transmitted into the plasma system in a faster manner.

[0161] 5. The EUV light output method based on the electrodeless pinch system provided in the embodiment of the present invention completely ionizes the first plasma group to generate the second plasma group, including: providing a preset electric pulse to the electrodeless pinch system to completely ionize the first plasma group; irradiating the position of the first plasma group with a preset pulse laser, and generating a second plasma group with a plasma temperature of 15eV-20eV under the combined action of the preset electric pulse and the preset pulse laser to produce an EUV light beam.

[0162] It should be noted that the preset electric pulse applies Lorentz force to the above-mentioned first plasma group, so that the low-valence lithium plasma is pinched until the radius reaches the minimum value. The position of the first plasma group is: the position where the plasma group with the minimum radius combines with the preset pulse laser. The plasma at this position has a minimum pinching radius, and its temperature and density reach maximum values.

[0163] It can be understood that the role of the preset pulse laser is to act on the first plasma group, that is, the low-valent lithium plasma, together with the preset electric pulse, to further shrink its size. Compared with using laser or electric pulse to compress plasma alone, this solution requires lower energy and is easier to implement technically; in addition, the addition of pulse laser is to utilize the high repetition frequency of laser to interact with plasma and thus increase the output power of extreme ultraviolet light.

[0164] Through the above steps, the stable absorption of pulsed laser and plasma cluster can be achieved to generate highly stable extreme ultraviolet light, which can save a lot of energy and improve the synchronization between plasma and pulsed laser.

[0165] 6. The EUV light output method based on the electrodeless pinch system provided in the embodiment of the present invention has a preset pulse width of the electric pulse of 100ns-200ns, a peak power of 6kA-8kA, and a repetition frequency of 2.5kHz-3kHz.

[0166] It can be understood that the pulse width, peak power and pulse repetition frequency of the preset electric pulse provided can make the main pulse power supply charge the capacitor while taking into account the cost of the extreme ultraviolet lithography technology.

[0167] 7. In the extreme ultraviolet light output method based on the electrodeless pinch system provided in the embodiment of the present invention, the preset pulse laser is a pulse laser generated after preprocessing, and the preprocessing includes shaping, beam expansion and / or focusing.

[0168] It should be noted that the preprocessing of the initial pulsed laser in the present invention includes at least one of shaping, beam expansion and focusing to obtain a light spot with high power and uniform energy distribution. Such a light beam can react quickly after interacting with the plasma group to produce stable extreme ultraviolet radiation.

[0169] It can be understood that the use of laser to act on low-valent lithium plasma does not have high requirements on parameters such as laser peak power, pulse width and repetition frequency. Therefore, there are many types of lasers to choose from, and the main function is to increase the repetition frequency of extreme ultraviolet radiation.

[0170] 8. The embodiment of the present invention further provides an EUV light output device based on an electrodeless pinch system, which is used to implement the above-mentioned EUV light output method based on an electrodeless pinch system.

[0171] The extreme ultraviolet light output device includes a beam output component for outputting an extreme ultraviolet light beam, and the beam output component includes: a reflection and collection mirror, which is correspondingly arranged at the output end of the electrodeless pinch system, and the reflection and collection mirror reflects and collects the extreme ultraviolet light beam; a heating element, which is arranged corresponding to the reflection and collection mirror, and the heating element is used to heat and maintain the temperature of the reflection and collection mirror.

[0172] The extreme ultraviolet light output device has the same beneficial effects as the above-mentioned extreme ultraviolet light output method, which will not be described in detail here.

[0173] 9. An embodiment of the present invention further provides a computer device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to execute the computer program to implement the above-mentioned extreme ultraviolet light output method based on the electrodeless pinch system.

[0174] The computer device has the same beneficial effects as the above-mentioned extreme ultraviolet light output method, which will not be described in detail here.

[0175] The above is a detailed introduction to an extreme ultraviolet light output method, device and equipment based on an electrodeless pinch system disclosed in an embodiment of the present invention. Specific examples are used in this article 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 idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention, and any modifications, equivalent substitutions and improvements made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for EUV light output based on an electrodeless pinch system, It is characterized in that The method comprises: Pre-ionizing lithium gas in the electrodeless pinch system to generate a first plasma cluster; Completely ionizing the first plasma group to generate a second plasma group to produce an extreme ultraviolet light beam; The beam output component outputs the extreme ultraviolet beam, and the beam output component outputting the extreme ultraviolet beam is kept heated.

2. The method for outputting extreme ultraviolet light based on an electrodeless pinch system as claimed in claim 1, It is characterized in that The preset temperature for maintaining heating is 400°C-750°C.

3. The method for outputting extreme ultraviolet light based on an electrodeless pinch system as claimed in claim 2, It is characterized in that The first plasma group includes lithium plasma with a valence state of +1, and the second plasma group includes lithium plasma with a valence state of +2 and +3.

4. The method for outputting extreme ultraviolet light based on an electrodeless pinch system as claimed in claim 3, It is characterized in that Pre-ionizing lithium gas in the electrodeless pinch system to generate a first plasma group comprises: Sublimating or melting and then gasifying a preset lithium target to generate the lithium gas and introduce it into the electrodeless pinch system; The lithium gas introduced into the electrodeless pinch system is pre-ionized, and at least a portion of the lithium gas is converted into the first plasma group.

5. The method for outputting extreme ultraviolet light based on an electrodeless pinch system as claimed in claim 4, It is characterized in that Completely ionizing the first plasma group to generate a second plasma group includes: Providing a preset electric pulse to the electrodeless pinch system to completely ionize the first plasma group; A preset pulse laser is irradiated at the position where the first plasma group is located, and a second plasma group with a plasma temperature of 15e V-20e V is generated under the combined action of the preset electric pulse and the preset pulse laser to produce an extreme ultraviolet light beam.

6. The method for outputting extreme ultraviolet light based on an electrodeless pinch system as claimed in claim 5, It is characterized in that The preset electric pulse has a pulse width of 100ns-200ns, a peak power of 6kA-8kA, and a repetition frequency of 2.5kHz-3kHz.

7. The method for outputting extreme ultraviolet light based on an electrodeless pinch system as claimed in claim 5, It is characterized in that The preset pulse laser is a pulse laser generated after preprocessing, and the preprocessing includes shaping, beam expansion and / or focusing.

8. An EUV light output device based on an electrodeless pinch system, used to implement the EUV light output method based on an electrodeless pinch system according to any one of claims 1 to 7.

9. The EUV light output device based on the electrodeless pinch system as claimed in claim 8, It is characterized in that The extreme ultraviolet light output device includes a beam output component for outputting an extreme ultraviolet light beam, and the beam output component includes: A reflection and collection mirror, which is arranged correspondingly at the output end of the electrodeless pinch system, and reflects and collects the extreme ultraviolet light beam; A heating element is arranged corresponding to the reflection and collection mirror, and is used for heating and maintaining the temperature of the reflection and collection mirror.

10. A computer device, It is characterized in that The method comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to execute the computer program to implement the extreme ultraviolet light output method based on an electrodeless pinch system according to any one of claims 1 to 7.

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