Method and device for generating extreme ultraviolet lithography light source

Abstract

The invention discloses an extreme ultraviolet lithography light source generation method and device, and the method comprises the steps: generating a micron-sized metal liquid film target material with uniform and stable thickness in a vacuum environment, and carrying out the focusing bombardment of the target material through a 2-micron wavelength laser beam 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. Wherein the metal liquid film target is bombarded by virtue of a 2-micron solid laser so as to obtain extreme ultraviolet light, and the metal liquid film generating device ensures that the metal liquid film can maintain uniform and stable micron-sized thickness by virtue of accurate temperature control and flow control means. In addition, the laser coupling and focusing module can adjust spatial and temporal distribution of light source pulses, and the liquid film target can absorb driving energy efficiently. The method has the advantages that energy consumption is reduced, efficiency and stability are improved, and strong power is injected for flourishing development of the photoetching 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 development 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 lithography processes. Currently, the mainstream EUV light source generation method relies on carbon dioxide lasers to excite tin droplets to produce extreme ultraviolet light with a wavelength of 13.5 nanometers. However, this technical path faces multiple severe challenges, which hinder its widespread application in efficient, stable and low-cost chip manufacturing.

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

[0004] Secondly, the generation, precise control and efficient coordination of tin droplets with laser pulses is another major technical challenge. The tiny size and rapid change characteristics of tin droplets make it extremely difficult to generate and precisely control them, which in turn affects the stability and consistency of the output of extreme ultraviolet light. This instability directly limits the yield and production efficiency in the chip manufacturing process, and has become 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 prior art, the present invention provides a method and device for generating an extreme ultraviolet lithography light source, 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 light source stability, simplify equipment architecture, and reduce costs, thereby effectively promoting 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 in that it includes:

[0008] In a vacuum environment, a metal liquid film target is generated along the dripping direction, 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 on 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 also provides an extreme ultraviolet lithography light source generating device, which is characterized in that it includes:

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

[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 laser module, and focus and bombard the metal liquid film target to achieve efficient energy conversion, while adjusting 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 comprises:

[0018] Container, used to hold 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 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 the top of the container, for applying gas pressure to allow 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 metal liquid film with adjustable thickness in the container. The metal liquid film serves as the target surface of 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 beneficial effects:

[0030] 1. Equipment simplification and cost optimization: Abandoning the complex architecture of traditional carbon dioxide lasers, taking the compact and efficient 2-micron solid laser as the core, and matching it with streamlined liquid film generation and other modules, the equipment size is reduced, the purchase cost is significantly reduced, and the operation and maintenance complexity and cost are reduced simultaneously, thereby improving the industrial economic benefits and equipment deployment flexibility.

[0031] 2. Improved energy conversion efficiency and stability: Uniform and stable liquid film is conducive to laser energy absorption. Compared with traditional tin droplet technology, the efficiency of extreme ultraviolet light generation is improved, providing a stable light source for high-precision photolithography pattern replication. Through the liquid film generation and maintenance module, a micron-thick metal liquid film target material is stably generated along the dripping direction in a vacuum environment, which improves the laser energy absorption efficiency and thus enhances the efficiency of extreme ultraviolet light generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of an 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 diagram of the structure of the nozzle in the present invention;

[0035] In the figure:

[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 in conjunction with the embodiments and drawings. The present application can be implemented in many different forms, which should not limit the scope of protection of the present invention. The terms used in the present application specification are for describing specific embodiments and are not intended to limit the present application.

[0039] 2-micron solid-state laser module: The core component is a 2-micron solid-state laser, which uses advanced laser gain media (such as specifically doped crystal materials) to stably output high-power laser beams with wavelengths in the range of 1800-2100 nanometers and pulse widths that are flexibly adjustable in the range of 5-50 nanoseconds. The laser is equipped with a precise power control system and advanced beam shaping submodules, which can accurately set the output power according to the requirements of the lithography process, and optimize the output beam spot shape, divergence angle and other parameters to meet the requirements of liquid film bombardment, providing stable and adaptive energy input for subsequent extreme ultraviolet light generation.

[0040] Liquid surface generation and maintenance module

[0041] Material selection:

[0042] The container is made of quartz ceramic composite material, which has excellent high temperature resistance and can withstand temperatures of at least 800°C. It also has strong chemical stability and can effectively prevent chemical reactions with the molten metal it contains. The molten metal contained inside is tin, which exhibits good performance in generating 13.5 nanometer extreme ultraviolet light under specific temperatures and laser action.

[0043] Generation method:

[0044] Container and auxiliary system design:

[0045] The bottom of the special container is equipped with a high-precision temperature control system. The accuracy of its temperature sensor can reach ±0.01°C. The heating element can achieve precise temperature adjustment within the range of 200-400°C. Microfluidic channels and micro pumps are set on the edge of the container. The inner diameter of the microfluidic channel is 0.1-0.5 mm. The flow adjustment accuracy of the micro pump is ±0.01 ml / min, which can accurately control the melt flow rate within the range of 0.1-1 ml / min. The liquid surface is generated in a vacuum environment with a vacuum degree better than 1×10-3 Pascal by using the surface tension characteristics of the liquid itself.

[0046] Liquid film formation principle: By adjusting the temperature control system and microfluidic channels, the temperature of the tin solution is set at 240-400°C and the flow rate is set 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 later.

[0047] 3. Laser focusing and energy coupling module: It consists of a lens group with high numerical aperture (up to 0.4-0.6) and an intelligent wavefront correction element. The lens group focuses the 2-micron laser beam onto the liquid film to increase the energy density.

[0048] 4. The multi-layer reflector group deployed around the liquid film is designed according to the reflection characteristics of extreme ultraviolet light (using high reflectivity materials and optimized deposition process) to achieve high reflectivity at a wavelength of 13.5 nanometers. The reflector group is designed with asymmetric optical surfaces to efficiently collect extreme ultraviolet light and converge it into a high vacuum light guide pipe.

[0049] See also Figure 1 , Figure 1 It is a structural schematic diagram of the extreme ultraviolet lithography light source generating device of the present invention, as shown in the figure, comprising: 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 to emit 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 radiated extreme ultraviolet light is collected and focused into the optical path transmission system 15 through the collecting mirror 14.

[0050] Figure 2 The specific structure of the liquid film generating device includes: 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. The air pump 21 applies air pressure to the inert gas to promote the flow of the entire liquid; the quartz ceramic composite material container 22 has high temperature resistance and can withstand a high temperature of at least 800°C and has strong chemical stability, and is used to hold molten metal inside; a tin metal solution 23 with a purity of 99.9999%; a high-precision temperature control system 24, which is arranged at the bottom of the container, the temperature sensor has an accuracy of ±0.01°C, and the heating element can adjust the temperature range to 200°C-400°C; a microfluidic channel and a micro pump 25, the microfluidic channel is arranged at the edge of the container, the inner diameter is 0.1-0.5 mm, and the flow adjustment accuracy of the micro pump is ±0.01 ml / min, which is used to control the flow rate of the molten metal within the range of 0.1-1 ml / min; a metal liquid film 27 is generated by a nozzle 26, and the liquid film width is 1.0-5.0 mm and the thickness is 1.0-5.0 μm;

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

[0052] The present invention provides a lithography light source device that uses a 2-micron solid laser to bombard a metal liquid film to generate extreme ultraviolet light. The present invention uses a 2-micron driving light source, which bombards a metal liquid film target generated by a metal liquid film generating device through a laser focusing and energy coupling module to generate extreme ultraviolet radiation. However, the metal used in the device is not limited to tin, but is applicable to gallium-indium-tin alloy, gallium-zinc alloy or other material combinations that have been experimentally verified to be conducive to the efficient generation of extreme ultraviolet light. In addition, the liquid film generating device in the present invention includes but is not limited to the above structures, which includes all structures that can generate the same liquid film.

Claims

1. A method for generating an extreme ultraviolet lithography light source, characterized in that: include: In a vacuum environment, a metal liquid film target is generated along the dripping direction, 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 on 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.

2. 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 material along the dripping direction in a vacuum environment and keep the metal liquid film target material uniform and stable at the micron level thickness; 2-micron solid-state laser module, used to emit a laser beam with a wavelength of 2 microns; The laser focusing and energy coupling module is used to receive the laser beam emitted by the 2-micron solid laser module, and focus and bombard the metal liquid film target to achieve efficient energy conversion, while adjusting the spatiotemporal distribution of the laser beam to promote the metal liquid film target to absorb energy, thereby generating extreme ultraviolet light.

3. The extreme ultraviolet lithography light source generating device according to claim 2, 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.

4. The extreme ultraviolet lithography light source generating device according to claim 2, characterized in that: The liquid film generation and maintenance module comprises: Container, used to hold molten metal; A temperature control system, disposed at the bottom of the container, comprising a temperature sensor and a heating element; A microfluidic channel 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 the top of the container, for applying gas pressure to allow 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 metal liquid film with adjustable thickness in the container. The metal liquid film serves as the target surface of the laser to generate extreme ultraviolet light.

5. The extreme ultraviolet lithography light source generating device according to claim 4, characterized in that: The molten metal is tin with a purity of 99.9999%.

6. The extreme ultraviolet lithography light source generating device according to claim 4, 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.

7. The extreme ultraviolet lithography light source generating device according to claim 4, 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, which ensures that the molten metal flows evenly and stably to the liquid film nozzle and forms a metal liquid film of uniform thickness.

8. The extreme ultraviolet lithography light source generating device according to claim 2, 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, and the numerical aperture of the lens group is between 0.4 and 0.

6.

9. The extreme ultraviolet lithography light source generating device according to any one of claims 2 to 8, characterized in that: A vacuum pump system is also included for maintaining a vacuum environment to ensure the vacuum degree during the liquid film formation process.

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