A method and device for generating an extreme ultraviolet lithography light source

Abstract

A method and device for generating an extreme ultraviolet lithography light source, the method comprising generating a metal liquid film target material with a uniform and stable micron-level thickness in a vacuum environment, and using a 2-micron wavelength laser beam to focus and bombard the target material to generate extreme ultraviolet light; the device comprises a 2-micron solid laser module, a liquid film generation and maintenance module, a laser focusing and energy coupling module, and an extreme ultraviolet light collection and transmission module. The extreme ultraviolet light is obtained by bombarding the metal liquid film target with a 2-micron solid laser, and the metal liquid film generation device ensures that the metal liquid film can maintain a uniform and stable micron-level thickness by means of precise temperature control and flow control. In addition, the laser coupling and focusing module can adjust the spatiotemporal distribution of the light source pulse, which is beneficial for the liquid film target to efficiently absorb the driving energy. The present invention has the advantages of reducing energy consumption, improving efficiency and stability, and has injected strong impetus into the vigorous development of lithography technology and the chip manufacturing industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithography light sources, and in particular relates to a method and device for generating an extreme ultraviolet lithography light source. Background Art

[0002] With the continuous advancement of modern lithography technology and the increasing precision requirements of chip manufacturing, extreme ultraviolet lithography (EUVL) light sources have become the key to breaking through the bottleneck of the lithography process. Currently, the mainstream EUV light source generation method relies on carbon dioxide lasers to excite tin droplets to produce 13.5-nanometer wavelength EUV light. However, this technical approach faces multiple severe challenges, hindering its widespread application in efficient, stable, and low-cost chip manufacturing.

[0003] First, CO2 laser systems are not only bulky and complex, but also extremely energy-intensive, resulting in high equipment costs. As the semiconductor industry continues to increase its requirements for the power density, stability, and precision of photolithography light sources, the performance of traditional CO2 laser systems has gradually approached physical limits, and technological development has reached a bottleneck.

[0004] Secondly, generating and precisely controlling the tin droplets and efficiently coordinating them with the laser pulses presents another major technical challenge. The tiny size and rapidly changing nature of the tin droplets make their stable generation and precise manipulation extremely difficult, which in turn affects the stability and consistency of the EUV light output. This instability directly limits the yield rate and production efficiency of the chip manufacturing process, becoming a major obstacle to the large-scale application of EUVL technology. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned existing technologies, the present invention provides a method and device for generating an extreme ultraviolet lithography light source, which adopts a metal liquid film as the light source target material of the extreme ultraviolet lithography machine, and uses a 2-micron solid laser to act on the metal liquid film to generate 13.5-nanometer extreme ultraviolet light, so as to achieve efficient energy conversion, improve the stability of the light source, simplify the equipment architecture, reduce costs, and effectively promote the breakthrough development of lithography technology and chip manufacturing industry.

[0006] The technical solution of the present invention:

[0007] In one aspect, the present invention provides a method for generating an extreme ultraviolet lithography light source, which is characterized by comprising:

[0008] A metal liquid film target is generated along the dripping direction in a vacuum environment, and the metal liquid film target can maintain a uniform and stable thickness at the micron level;

[0009] generating a laser beam with a wavelength of 2 microns that is energy-coupled with the metal liquid film target;

[0010] The laser beam is focused and bombarded onto the metal liquid film target material, so that the laser energy can be absorbed by the metal liquid film target material to the maximum extent and converted into plasma radiation, thereby generating extreme ultraviolet light.

[0011] On the other hand, the present invention further provides an extreme ultraviolet lithography light source generating device, which is characterized by comprising:

[0012] The liquid film generation and maintenance module is used to generate a metal liquid film target along the dripping direction in a vacuum environment and maintain the uniform and stable thickness of the metal liquid film target at the micron level;

[0013] 2-micron solid-state laser module, used to emit a laser beam with a wavelength of 2 microns;

[0014] The laser focusing and energy coupling module is used to receive the laser beam emitted by the 2-micron solid-state laser module, focus and bombard the metal liquid film target to achieve efficient energy conversion, and adjust the spatiotemporal distribution of the laser beam to promote the metal liquid film target to absorb energy, thereby generating extreme ultraviolet light.

[0015] Furthermore, it also includes: an extreme ultraviolet light collection and transmission module, which is used to collect the extreme ultraviolet light and transmit it to the subsequent photolithography process.

[0016] Furthermore, it also includes: a vacuum pump system for maintaining a vacuum environment to ensure the vacuum degree during the liquid film formation process.

[0017] Preferably, the liquid film generation and maintenance module includes:

[0018] Container for holding molten metal;

[0019] a temperature control system, disposed at the bottom of the container, comprising a temperature sensor and a heating element;

[0020] A microfluidic channel is connected to the bottom outlet of the container,

[0021] a micro pump, disposed in the microfluidic channel, for controlling the flow rate of the molten metal;

[0022] a liquid film nozzle connected to the bottom of the microfluidic channel;

[0023] an inert gas pump, disposed on top of the container, for applying gas pressure to cause the molten metal to flow out through the container, the microfluidic channel, and the liquid film nozzle;

[0024] By controlling the temperature and flow rate of the molten metal and utilizing the surface tension of the liquid itself, the molten metal forms a stable and thickness-adjustable metal liquid film in the container. The metal liquid film serves as the target surface for the laser to generate extreme ultraviolet light.

[0025] Furthermore, the molten metal is tin with a purity of 99.9999%.

[0026] Furthermore, the container is made of a quartz ceramic composite material, has high temperature resistance, can withstand a high temperature of at least 800° C., and has strong chemical stability.

[0027] Furthermore, the inner diameter of the microfluidic channel is 0.1-0.5 mm, and the slit width of the liquid film nozzle is 30-50 μm and the length is 200-300 μm, ensuring that the molten metal flows evenly and stably to the liquid film nozzle and forms a metal liquid film of uniform thickness.

[0028] Furthermore, the laser focusing and energy coupling module is composed of a high numerical aperture lens group and an adaptive wavefront correction element, and the numerical aperture of the lens group is between 0.4 and 0.6.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1. Equipment simplification and cost optimization: Abandoning the complex architecture of traditional CO2 lasers, the system uses a compact and efficient 2-micron solid-state laser as its core, combined with streamlined liquid film generation and other modules. This reduces the size of the equipment, significantly lowers the acquisition cost, and reduces the complexity and cost of operation and maintenance, thereby improving industrial economic benefits and equipment deployment flexibility.

[0031] 2. Improved energy conversion efficiency and stability: A uniform and stable liquid film facilitates laser energy absorption. Compared to traditional tin droplet technology, this technology improves the efficiency of EUV light generation, providing a stable light source for high-precision photolithography pattern replication. The liquid film generation and maintenance module stably generates a micron-thick metal liquid film target along the dripping direction in a vacuum environment, improving laser energy absorption efficiency and, in turn, enhancing EUV light generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of the extreme ultraviolet lithography light source generating device of the present invention;

[0033] Figure 2 It is a structural schematic diagram of the liquid film generation and maintenance module in the present invention;

[0034] Figure 3 It is a schematic structural diagram of the nozzle in the present invention;

[0035] In the picture:

[0036] 11-2 micron laser driving light source; 12-beam shaping and focusing system; 13-metal liquid film target; 14-collecting mirror; 15-optical transmission system;

[0037] 21-air pump; 22-container; 23-metal solution; 24-temperature control system; 25-microfluidic channel and micro pump; 26-liquid film nozzle; 27-metal liquid film. DETAILED DESCRIPTION

[0038] The present invention is further described below with reference to the embodiments and accompanying drawings. The present invention can be implemented in many different forms, which should not limit the scope of protection of the present invention. The terms used in this specification are for describing specific embodiments and are not intended to limit the present invention.

[0039] 2-micron solid-state laser module: The core component is a 2-micron solid-state laser. Using an advanced laser gain medium (such as a specifically doped crystal material), it can stably output a high-power laser beam with a wavelength in the 1800-2100 nanometer range and a flexibly adjustable pulse width between 5 and 50 nanoseconds. Equipped with a sophisticated power control system and advanced beam shaping submodule, the laser can precisely set the output power according to the requirements of the lithography process. It also optimizes the output beam's spot shape, divergence angle, and other parameters to meet the requirements for liquid film bombardment, providing stable and adaptive energy input for subsequent EUV light generation.

[0040] Liquid surface generation and maintenance module

[0041] Material selection:

[0042] The container is made of a quartz ceramic composite material, which exhibits excellent high-temperature resistance, withstanding temperatures of at least 800°C. Its chemical stability effectively prevents chemical reactions with the molten metal it contains. The molten metal inside is tin, a metal that exhibits excellent performance in generating 13.5-nanometer extreme ultraviolet light under specific temperatures and laser exposure.

[0043] Generation method:

[0044] Container and auxiliary system design:

[0045] The bottom of the specially designed container is equipped with a high-precision temperature control system. Its temperature sensor has an accuracy of ±0.01°C, and the heating element allows for precise temperature regulation within a range of 200-400°C. Microfluidic channels and micropumps are located along the edge of the container. The inner diameter of the microfluidic channels is 0.1-0.5 mm, and the micropump has a flow rate regulation accuracy of ±0.01 ml / min, accurately controlling the melt flow rate within a range of 0.1-1 ml / min. By utilizing the surface tension of the liquid, a liquid surface is generated in a vacuum environment with a vacuum degree better than 1×10-3 Pascals.

[0046] Liquid film formation principle: By adjusting the temperature control system and microfluidic channels, the tin solution temperature is kept at 240-400°C and the flow rate is kept at 0.2-0.6 ml / min. A liquid plane with a thickness of 1.0-5.0 microns is formed in the container and can be precisely adjusted according to the requirements of lithography. This plane serves as the target surface for the laser to generate extreme ultraviolet light.

[0047] 3. Laser Focusing and Energy Coupling Module: This module consists of a high-numerical-aperture lens system (up to 0.4-0.6) and an intelligent wavefront correction element. The lens system focuses a 2-micron laser beam onto the liquid film, increasing energy density.

[0048] 4. The multilayer reflective mirrors deployed around the liquid film are designed to reflect extreme ultraviolet light (using high-reflectivity materials and an optimized deposition process), achieving high reflectivity at a wavelength of 13.5 nanometers. The reflective mirrors utilize an asymmetric optical surface design to efficiently collect the extreme ultraviolet light and focus it into a high-vacuum light guide.

[0049] See also Figure 1 , Figure 1 This is a structural schematic diagram of the extreme ultraviolet lithography light source generating device of the present invention, as shown in the figure, including: a 2-micron solid laser 11, a laser focusing and energy coupling module 12, a liquid film generation and maintenance module 13, an extreme ultraviolet light collection 14 and a transmission module 15. The 2-micron laser drives the light source 11, emitting a single-pulse high-energy Gaussian beam, the pulse width and energy of which can be adjusted; the Gaussian beam passes through the beam shaping and focusing system 12 and bombards the metal liquid film target 13 in the optimal form, and the thickness of the metal liquid film target can be adjusted; the plasma-generated extreme ultraviolet light is collected and focused by the collecting mirror 14 into the optical path transmission system 15.

[0050] Figure 2 The liquid film generating device has a specific structure, including: an air pump 21; a quartz ceramic composite material container 22; a metal solution 23; a high-precision temperature control system 24; a microfluidic channel and a micro pump 25; a liquid film nozzle 26 and a metal liquid film 27. An air pump 21 applies pressure from an inert gas to propel the overall flow of the liquid. A quartz ceramic composite container 22, with high-temperature resistance capable of withstanding temperatures of at least 800°C and strong chemical stability, contains molten metal. A tin metal solution 23 with a purity of 99.9999% is provided. A high-precision temperature control system 24 is located at the bottom of the container, with a temperature sensor having an accuracy of ±0.01°C and a heating element with an adjustable temperature range of 200°C-400°C. A microfluidic channel and micropump 25 are provided at the edge of the container, with an inner diameter of 0.1-0.5 mm and a flow rate regulation accuracy of ±0.01 ml / min, for controlling the flow rate of the molten metal within a range of 0.1-1 ml / min. A nozzle 26 generates a metal liquid film 27 with a width of 1.0-5.0 mm and a thickness of 1.0-5.0 μm.

[0051] Figure 3 3 is a structural diagram of the nozzle used in the present invention, wherein the nozzle slit has a width of 30-50 microns and a length of 200-300 microns.

[0052] The present invention provides a lithography light source device that generates extreme ultraviolet light by bombarding a metal liquid film with a 2-micron solid-state laser. This device uses a 2-micron driving light source, coupled through a laser focusing and energy coupling module, to bombard a metal liquid film target produced by a metal liquid film generating device, generating extreme ultraviolet radiation. However, the device is not limited to tin; it is also applicable to gallium-indium-tin alloys, gallium-zinc alloys, or other material combinations proven to be effective for efficient extreme ultraviolet light generation. Furthermore, the liquid film generating device of the present invention includes, but is not limited to, the aforementioned structures, encompassing all structures capable of producing the same liquid film.

Claims

1. An extreme ultraviolet lithography light source generating device, characterized in that: include: The liquid film generation and maintenance module is used to generate a metal liquid film target along the dripping direction in a vacuum environment and maintain the uniform and stable thickness of the metal liquid film target at the micron level; 2-micron solid-state laser module, used to emit a laser beam with a wavelength of 2 microns; a laser focusing and energy coupling module, configured to receive the laser beam emitted by the 2-micron solid-state laser module, focus and bombard the metal liquid film target to achieve efficient energy conversion, and adjust the spatiotemporal distribution of the laser beam to promote the absorption of energy by the metal liquid film target, thereby generating extreme ultraviolet light; Wherein, the liquid film generation and maintenance module includes: Container for holding molten metal; a temperature control system, disposed at the bottom of the container, comprising a temperature sensor and a heating element; A microfluidic channel is connected to the bottom outlet of the container, a micro pump, disposed in the microfluidic channel, for controlling the flow rate of the molten metal; a liquid film nozzle connected to the bottom of the microfluidic channel; an inert gas pump, disposed on top of the container, for applying gas pressure to cause the molten metal to flow out through the container, the microfluidic channel, and the liquid film nozzle; By controlling the temperature and flow rate of the molten metal and utilizing the surface tension of the liquid itself, the molten metal forms a stable and thickness-adjustable metal liquid film in the container. The metal liquid film serves as the target surface for the laser to generate extreme ultraviolet light.

2. The extreme ultraviolet lithography light source generating device according to claim 1, characterized in that: Also includes: The extreme ultraviolet light collection and transmission module is used to collect the extreme ultraviolet light and transmit it to the subsequent photolithography process.

3. The extreme ultraviolet lithography light source generating device according to claim 1, characterized in that: The molten metal is tin with a purity of 99.9999%.

4. The extreme ultraviolet lithography light source generating device according to claim 1, characterized in that: The container is made of a quartz ceramic composite material, has high temperature resistance, can withstand a high temperature of at least 800° C., and has strong chemical stability.

5. The extreme ultraviolet lithography light source generating device according to claim 1, characterized in that: The inner diameter of the microfluidic channel is 0.1-0.5 mm, and the slit width of the liquid film nozzle is 30-50 μm and the length is 200-300 μm, ensuring that the molten metal flows evenly and stably to the liquid film nozzle and forms a metal liquid film of uniform thickness.

6. The extreme ultraviolet lithography light source generating device according to claim 1, characterized in that: The laser focusing and energy coupling module is composed of a high numerical aperture lens group and an adaptive wavefront correction element. The numerical aperture of the lens group is between 0.4 and 0.

6.

7. The extreme ultraviolet lithography light source generating device according to any one of claims 1-2, characterized in that: It also includes a vacuum pump system for maintaining a vacuum environment to ensure the vacuum degree during the liquid film formation process.

8. A method for generating an extreme ultraviolet lithography light source, using the device according to any one of claims 1 to 7, characterized in that: include: A metal liquid film target is generated along the dripping direction in a vacuum environment, and the metal liquid film target can maintain a uniform and stable thickness at the micron level; generating a laser beam with a wavelength of 2 microns that is energy-coupled with the metal liquid film target; The laser beam is focused and bombarded onto the metal liquid film target material, so that the laser energy can be absorbed by the metal liquid film target material to the maximum extent and converted into plasma radiation, thereby generating extreme ultraviolet light.

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