Point light source collection system

Abstract

The present application relates to a kind of point light source collection systems, it is characterized in that, including: drive source, the drive source is configured to be aimed at the beam current to target material, to produce divergent light at light emitting point;And transmission collection element, the transmission collection element is configured to the divergent light from the target material is collected and converges;Wherein, the transmission collection element includes the lobster eye structure with hole, and wherein the collection solid angle of the transmission collection element is in the range of 2-5.

Description

Technical Field

[0001] This invention relates to a point light source collection system, specifically, to a collection system that uses a transmission collection element to collect light in the extreme ultraviolet to X-ray bands generated by a driving source. Background Technology

[0002] Incoherent extreme ultraviolet to X-ray (50nm-0.01nm) point light sources generated by laser-driven, plasma discharge, and electron beam-driven methods are widely used in integrated circuit lithography, ultra-precision metrology (mask defects, wafer defects), and absorption spectroscopy. Due to their divergent light emission characteristics, collection devices are needed to collect the light source and improve the effective utilization of power and brightness.

[0003] Current mainstream light source collection employs reflective systems, primarily using two structures: multi-layered parabolic mirrors and Wolter mirrors (single or multi-layered) grazing incidence systems. To achieve high solid angle collection while simultaneously protecting against contamination, both types of mirrors require large dimensions (m-scale, with Wolter mirrors requiring multi-layered structures) and high loads (mirrors weighing >50kg), resulting in high costs (millions of dollars). Furthermore, to filter visible and infrared light, parabolic mirrors require the fabrication of gratings for filtering and the use of multi-layered film technology (>30 nm layers) to achieve reflection in specific extreme ultraviolet to X-ray bands, making full-spectrum reflection impossible.

[0004] In addition, there are also transmission systems based on capillary tubes, but the solid angle of this system is subject to processing limitations (solid angle <1), and heat dissipation is relatively difficult to adjust. Summary of the Invention

[0005] Unlike the two current designs, the lobster-eye technology in X-rays has also been used in recent years for collimation and focusing of extreme ultraviolet to X-rays, and it can accommodate large collection angles and miniaturized size. This disclosure aims to propose a new low-cost (hundreds of thousands of units), compact and lightweight (<1 kg), large collection solid angle (2-5), easy wavelength adjustment, high resistance to particulate contamination and heat, and high transmittance transmission-type extreme ultraviolet to X-ray band point source collection system based on lobster-eye technology.

[0006] According to a first aspect of this disclosure, a point light source collection system is provided, characterized in that it comprises: a driving source configured to direct a beam toward a target to generate divergent light at a light-emitting point; and a transmission collection element configured to collect and converge the divergent light from the target; wherein the transmission collection element comprises a lobster-eye structure with holes, and wherein the collection solid angle of the transmission collection element is in the range of 2-5.

[0007] Optionally, the distance between the light-emitting point and the center of the transmission collecting element is in the range of 100mm to 400mm.

[0008] Optionally, the width of the transmission collecting element is in the range of 200 mm to 700 mm.

[0009] Optionally, the magnification of the light source from the driving source to the transmission collecting element is in the range of 2 to 10 times.

[0010] Optionally, the radiating light includes light in the extreme ultraviolet to X-ray bands.

[0011] Optionally, the transmission collecting element has an adjustable radius of curvature, wherein the radius of curvature is in the range of 10-1000 mm.

[0012] Optionally, the aperture of the transmission collecting element has an aspect ratio in the range of 1-1000.

[0013] Optionally, the aperture shape of the transmission collecting element is square or circular.

[0014] Optionally, the transmission collecting element has a light-shielding film configured to block light with a specific wavelength.

[0015] Optionally, the point light source collection system further includes an adjustment mechanism, which includes: a first adjustment mechanism for adjusting the radius of curvature of the transmission collection element; and a second adjustment mechanism for adjusting the distance between the light-emitting point and the center of the transmission collection element.

[0016] Optionally, the point light source collection system further includes a cooling element for cooling the transmission collection element.

[0017] Optionally, the point light source collection system also includes a reflection collection element.

[0018] Optionally, the driving source is a laser driving source, an electron beam driving source, or a discharge driving source.

[0019] According to a second aspect of this disclosure, an apparatus is provided, including a point light source collection system as described above. Attached Figure Description

[0020] This application can be better understood by describing exemplary embodiments of the application in conjunction with the accompanying drawings, in which:

[0021] Figure 1 A schematic diagram of a point light source collection system according to an exemplary embodiment of this application is shown.

[0022] Figure 2A schematic diagram of the transmission collection principle according to an exemplary embodiment of this application is shown.

[0023] Figure 3 A schematic diagram illustrating parameter calculations for a transmission collection principle according to an exemplary embodiment of this application is shown.

[0024] Figure 4 A graph showing the aspect ratio, wavelength selection, and collection efficiency of a lobster-eye structure-based transmission collection element according to an exemplary embodiment of this application is illustrated. Detailed Implementation

[0025] The following describes specific embodiments of this application. It should be noted that, in order to maintain brevity, this specification cannot provide a detailed description of all features of the actual embodiments. It should be understood that, in the actual implementation of any embodiment, just as in any engineering or design project, various specific decisions are often made to achieve the developer's specific goals and to meet system-related or business-related constraints, and this can change from one embodiment to another. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this disclosure are merely conventional technical means and should not be construed as insufficient content of this disclosure.

[0026] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the patent application description and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the element or object preceding "comprising" or "including" encompasses the element or object listed following "comprising" or "including" and its equivalents, and do not exclude other elements or objects. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0027] In this disclosure, a structure may be referred to as "for" or "configured to" perform certain tasks, even if the structure is not currently in operation. For example, "laser for / configured to output laser" is intended to cover a laser having components that perform the function during operation, even if the laser is not currently in use (e.g., not connected to a power source).

[0028] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions. Similarly, unless otherwise specified, all technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0029] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0030] The point light source collection system provided according to the embodiments of this application is described in detail below with reference to the accompanying drawings.

[0031] refer to Figure 1 , Figure 1 A schematic diagram of a point light source collection system 100 according to an exemplary embodiment of this application is shown.

[0032] like Figure 1 As shown, the point light source collection system 100 according to an exemplary embodiment of this application may include a driving source 110, a transmission system 112, and a transmission collection element 120. The driving source 110 directs a beam toward a target 113 via the transmission system 112 to generate divergent light. The divergent light may be in the extreme ultraviolet band to the X-ray band, but this application is not limited to this.

[0033] The driving source 100 can be continuously triggered or pulsed triggered. In some embodiments, the driving source 110 can be in the form of a laser driving source, an electron beam driving source, or a discharge driving source. In some embodiments, the beam may include a laser beam, an electron beam, or a plasma beam.

[0034] The target material 113 can be, but is not limited to, various liquid targets (Ga / GaIn alloy / Sn / GaSn alloy, etc.). When the target material 113 falls to a certain position, the beam from the driving source 110 can be configured to interact with the target material 113 at that position to generate divergent light. This position is the light-emitting point, and the target material 113 at this position forms a point light source. The target material 113 is not limited to solid, gel, flowing liquid, or gas targets. The size of the point light source is in the range of 10nm-20mm.

[0035] The transmission collection element 120 collects the divergent light from the target 113 at the emission point and guides it to the user interface 130. The transmission collection element 120 may be disposed, for example, in a cavity 101. The cavity 101 may be compatible with both vacuum and non-vacuum environments.

[0036] As an example, the transmission collecting element 120 may have holes. The transmission collecting element 120 may include a light-shielding film 140. In some embodiments, the light-shielding film 140 may include an aperture coating and a back-side coating. The aperture coating may be a single-layer Au / Ni / Ru film or a multilayer film, with a film thickness in the range of 1nm-100nm, for example, 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 20nm, 25nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, or any value within that range. The back-side coating is not limited to various film structures such as Al / B / Cu, and the film thickness is in the range of 1nm-10mm, for example, 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, or any value within that range. The back-side coating can reflect visible and infrared light and achieve different bandpasses for different wavelengths. Through the aperture coating and back-side coating structure, the transmission collecting element 120 can block long-wave infrared light, visible light, and ultraviolet light of unwanted wavelengths. However, the present invention is not limited thereto.

[0037] In some embodiments, the transmission collecting element 120 may include a lobster eye structure with holes. The lobster eye structure transmission collecting element is a transmission element designed based on biomimetic principles, inspired by the structure of a lobster's eye. A lobster's eye consists of many square-shaped micro-channels with smooth walls pointing towards the same center, which allows light from all directions to be reflected and converged onto the retina within the small square holes, thereby achieving imaging.

[0038] Furthermore, the capillary structure's transmission collecting element consists of a cylindrical hollow glass capillary tube with one end slightly tapered. It can modulate the beam, transforming it from a divergent state into a parallel beam, and can also converge a parallel beam into a small focal spot. This lens has a power density gain of approximately 10 times and a divergence in the milliradian range. (See below for reference.) Figure 2 A detailed description of the lobster eye structure according to an exemplary embodiment of this application is provided.

[0039] Figure 2 A schematic diagram 200 illustrates the transmission collection principle according to an exemplary embodiment of this application.

[0040] like Figure 2As shown, the target material 210 (i.e., point light source) at the emitting point generates divergent light which is collected and collimated by the transmission collecting element. A side view of the transmission collecting element is shown as reference numeral 220. According to the side view 220, the transmission collecting element has a radius of curvature that can be in the range of 10-1000 mm.

[0041] In some embodiments, the transmission collecting element comprises a plurality of microchannels with smooth walls pointing toward a common center, also referred to herein as the focal point (F) of the transmission collecting element, forming a lobster-eye structure. As shown in the front view 230 of the transmission collecting element, the openings of the plurality of microchannels form multiple pores. The pores can have various shapes, such as square (square, rectangular) or circular. The size of the pores ranges from 10 μm to 1 mm. The ratio between the length of the microchannel and the opening size is called the pore aspect ratio, which can range from 1 to 1000. Furthermore, the aperture ratio of the transmission collecting element can range from 1% to 95%.

[0042] The transmission collection element can be a single lobster eye structure or a combination of multiple lobster eye structures, and its size can range from 10mm to 200mm.

[0043] Figure 3 A schematic diagram 300 illustrates the parameter calculation of the transmission collection principle according to an exemplary embodiment of this application.

[0044] This application utilizes a transmission collection element in the form of a lobster eye structure with holes, and adjusts the solid angle and collection efficiency by adjusting the size of its radius of curvature and the distance from the point light source to the center of the transmission collection element.

[0045] Specifically, firstly, based on optical requirements, the distance d1 from the point light source to the transmission collecting element and the light source magnification A are determined. In some embodiments, the distance d1 from the point light source to the center of the transmission collecting element is in the range of 100mm to 400mm, for example, 100mm, 150mm, 200mm, 250mm, 300mm, 350mm, 400mm, or any value within this range. In some embodiments, the light source magnification A is in the range of 2x to 10x, for example, 2x, 3x, 4x, 5x, 6x, 7x, 7.5x, 8x, 8.5x, 9x, 9.2x, 9.4x, 9.6x, 9.8x, 10x, or any value within this range.

[0046] Then, d2 is determined based on the imaging magnification formula. Specifically, the imaging magnification formula is (d2-d1) / d1=A, from which we obtain d2=(A+1)d1.

[0047] Next, the radius of curvature R of the transmission collecting element is determined based on the imaging relationship. Specifically, the imaging formula is 1 / d1 + 1 / d2 = 2 / R, from which we obtain R = 2d1d2 / (d1 + d2) = 2(A+1)d1 / (A+2). In particular, the focal length F of the transmission collecting element is F = R / 2 = (A+1)d1 / (A+2).

[0048] In addition, the collection angle α of the transmission collecting element can be determined, and thus the collection solid angle of the transmission collecting element can be determined. Specifically, Where L is the width of the transmission collecting element. In some embodiments, the width L of the transmission collecting element is in the range of 200mm to 700mm, such as 200mm, 250mm, 300mm, 350mm, 400mm, 500mm, 550mm, 600mm, 620mm, 640mm, 660mm, 680mm, 700mm, or any value within the range.

[0049] Therefore, the collected solid angle 4αcosα is obtained.

[0050] Then, the transmittance of the transmission collecting element is calculated as f = O × T, where O is the aperture ratio and T is the transmittance. Furthermore, the collection efficiency of the transmission collecting element is calculated as 2fαcosα / π.

[0051] In other words, by adjusting the distance from the point light source to the center of the transmission collecting element and the magnification of the light source, the radius of curvature of the transmission collecting element can be adjusted, and based on the radius of curvature, the width of the transmission collecting element can be adjusted, thereby adjusting the collection angle and solid angle of the transmission collecting element, as well as the transmittance and collection efficiency of the transmission collecting element.

[0052] Therefore, the technical solution of this application, by appropriately setting the position of the transmission collecting element, reduces the width of the transmission collecting element and increases the radius of curvature of the transmission collecting element while keeping the magnification unchanged, thereby achieving a higher solid angle (e.g., in the range of 2-5, for example, greater than 2.5) with the same width of the transmission collecting element, thus better improving the conversion efficiency of the available light source.

[0053] Figure 4 A graph showing the aspect ratio, wavelength selection, and collection efficiency of a lobster-eye structure-based transmission collection element according to an exemplary embodiment of this application is illustrated.

[0054] according to Figure 4It can be seen that, for the same X-ray energy, the collection efficiency increases with the increase of the aspect ratio of the transmission collection element. Simultaneously, it can be seen that the transmission collection element based on the lobster-eye structure according to the exemplary embodiments of this application has higher collection efficiency for light in the extreme ultraviolet to X-ray bands compared to other bands. In other words, the aspect ratio of the transmission collection element based on the lobster-eye structure according to the exemplary embodiments of this application has good selectivity for light in the extreme ultraviolet to X-ray bands.

[0055] Return to reference Figure 1 The point light source collection system 100 may further include an adjustment mechanism 150. The adjustment mechanism 150 may include a first adjustment mechanism and a second adjustment mechanism, wherein the first adjustment mechanism is used to adjust the radius of curvature (i.e., the width of the transmission collection element) of the transmission collection element 120, and the second adjustment mechanism is used to adjust the position of the transmission collection element 120 (i.e., the distance from the light-emitting point to the center of the transmission collection element 120). It should be noted that... Figure 1 The adjustment mechanism 150 shown is only a schematic block diagram, and for simplicity, the first adjustment mechanism and the second adjustment mechanism are not shown.

[0056] In some embodiments, the point light source collection system 100 may further include a cooling element 160 for cooling the transmission collection element 120. For example, the cooling element 160 may be an edge water-cooling system that utilizes edge water cooling to dissipate heat from the transmission collection element 120. The edge water-cooling system may have a power level in the range of 0.1mW to 10kW. It should be noted that... Figure 1 The cooling element 160 shown is only a schematic block diagram.

[0057] In some embodiments, the point light source collection system 100 may further include a gas contamination protection system 170 for protecting the transmission collection element 120 from gas contamination, thereby preventing particles and ions from contaminating the transmission collection element 120. It should be noted that... Figure 1 The gas pollution protection system 170 shown is only a schematic block diagram.

[0058] In some embodiments, the point light source collection system 100 may further include a reflection collection system (not shown), such as various coated reflective focusing mirrors or superstructure transmission elements. The coating on the surface of the reflection collection system includes, but is not limited to, a single-layer Au film, or multiple layers of grazing-incident or normal-incident high-reflectivity films such as Mo / Si, Mo / Be, and La / B. The reflection collection system can collect at least a portion of the divergent light from the target material 113 and reflect it to the user interface 130. The reflection collection system can also collect at least a portion of the divergent light from the target material 113 and reflect it to the transmission collection element 102, thereby improving the available light source conversion efficiency.

[0059] According to another exemplary embodiment of this application, a light source device is also provided. The light source device may include the point light source collection system described above. According to another exemplary embodiment of this application, a photolithography system is also provided. The photolithography system may include the light source device described above.

[0060] It should be understood that the above description is illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. Furthermore, many modifications can be made to adapt particular conditions or materials to the teachings of the various embodiments of the invention without departing from the scope of the invention. While the dimensions and types of materials described herein are used to define parameters of the various embodiments of the invention, the embodiments are not intended to be restrictive but are exemplary. Many other embodiments will become apparent to those skilled in the art upon reading the above description. Therefore, the scope of the various embodiments of the invention should be determined by reference to the appended claims and the full scope of their equivalents.

[0061] Industrial practicality

[0062] The point light source collection system of the present invention can be widely used in the collection system of point light sources in the extreme ultraviolet band to X-ray band generated by high-power driving sources such as laser driving sources, electron beam driving sources, and discharge driving sources.

Claims

1. A point light source collection system, characterized in that, include: A driving source configured to direct a beam toward a target to generate divergent light at the emission point; as well as A transmission collecting element configured to collect and converge divergent light from the target material; The transmission collecting element includes a lobster eye structure with holes, and the collecting solid angle of the transmission collecting element is in the range of 2-5.

2. The point light source collection system according to claim 1, characterized in that, The distance between the light-emitting point and the center of the transmission collecting element is in the range of 100mm to 400mm.

3. The point light source collection system according to claim 1, characterized in that, The width of the transmission collecting element is in the range of 200mm to 700mm.

4. The point light source collection system according to claim 1, characterized in that, The magnification of the light source from the driving source to the transmission collecting element is in the range of 2 to 10 times.

5. The point light source collection system according to claim 1, characterized in that, The diffused light includes light in the extreme ultraviolet to X-ray bands.

6. The point light source collection system according to claim 1, characterized in that, The transmission collecting element has an adjustable radius of curvature, wherein the radius of curvature is in the range of 10-1000 mm.

7. The point light source collection system according to claim 1, characterized in that, The aperture of the transmission collecting element has an aspect ratio in the range of 1-1000.

8. The point light source collection system according to claim 1, characterized in that, The aperture of the transmission collecting element is square or circular.

9. The point light source collection system according to claim 1, characterized in that, The transmission collecting element has a light-shielding film configured to block light of a specific wavelength.

10. The point light source collection system according to claim 1, characterized in that, It also includes an adjustment mechanism, which comprises: A first adjustment mechanism for adjusting the radius of curvature of the transmission collecting element; and A second adjustment mechanism for adjusting the distance between the light-emitting point and the center of the transmission collecting element.

11. The point light source collection system according to claim 1, characterized in that, Also includes: Cooling element for cooling the transmission collecting element.

12. The point light source collection system according to claim 1, characterized in that, It also includes a reflection-collecting element.

13. The point light source collection system according to claim 1, characterized in that, The driving source is a laser driving source, an electron beam driving source, or a discharge driving source.

14. An apparatus comprising a point light source collection system as claimed in any one of claims 1-11.

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