Superlens and photoetching machine

Abstract

The utility model discloses a super lens and a photoetching machine. The super lens comprises a substrate, a reflecting part and a structural surface, the substrate is used for providing support, a reflecting part and a structural surface are sequentially arranged on the substrate, the reflecting part is used for reflecting incident light to the structural surface, light enters the reflecting part after entering the structural surface, and the reflecting part reflects the light to the structural surface. The structural surface is provided with a micro-nano structure array, the structural surface is used for modulating emergent light, and after the light is reflected to the structural surface by the reflecting part, the light penetrates through the structural surface and is focused at one point. As the structural surface and the reflecting part are both of the plane structure, the super lens provided by the utility model realizes the reflecting function of an aspheric reflecting mirror by utilizing the structural surface on the basis of a plane reflecting mirror, so that the requirement on the surface type of each component is not required, and the manufacturing cost is reduced. Therefore, the processing difficulty of the super lens provided by the utility model is lower than that of a high-precision surface reflector, so that the production cost of the super lens is relatively low.

Description

Technical Field

[0001] The present application relates to the field of reflectors, and in particular to a super lens and a photolithography machine. Background Art

[0002] Due to its excellent optical performance, high-precision surface reflectors are widely used in high-end science and technology and industrial fields that require extremely high optical quality and precise control capabilities, such as astronomical observation, laser technology and optical communication, satellite communication and radar system, semiconductor manufacturing, medical and scientific research instruments, industrial detection and measurement, etc.

[0003] In the lithography technology in the field of semiconductor manufacturing, especially in extreme ultraviolet lithography, high-precision multilayer film mirrors are required to achieve nanoscale pattern transfer on silicon wafers. These mirrors must have extremely low roughness and highly precise curvature to meet the micro-machining requirements required for advanced integrated circuit manufacturing. Due to the difficulty in preparing high-precision surface mirrors, the production cost of high-precision surface mirrors is relatively high. Utility Model Content

[0004] In response to the above technical problems, the embodiments of the present application provide a metalens and a lithography machine, aiming to provide a low-cost metalens with a reflective function.

[0005] According to one aspect of an embodiment of the present application, a superlens is disclosed, comprising: a substrate, a reflection portion, and a structure surface, wherein the reflection portion is located between the structure surface and the substrate along a thickness direction, and the structure surface is provided with a micro-nano structure array;

[0006] Among them, after the light is incident on the structural surface, it enters the reflecting part; after the light is reflected by the reflecting part, it is emitted from the structural surface; the structural surface is used to converge the emitted light.

[0007] In some embodiments, the point where the light converges is the focus of the structural surface, and the phase distribution of the metalens satisfies:

[0008]

[0009] Among them, λ is the wavelength of the incident light, x is the horizontal coordinate of any position on the metalens, and y is the vertical coordinate of any position on the metalens; x0 is the horizontal coordinate of the focus of the structural surface, y0 is the vertical coordinate of the focus of the structural surface, f is the focal length of the structural surface; θ is the angle between the incident light and the structural surface.

[0010] In some embodiments, the reflective portion includes a first layered structure and a second layered structure, the first layered structure and the second layered structure are stacked in a thickness direction, and the refractive index of the first layered structure is unequal to the refractive index of the second layered structure.

[0011] In some embodiments, the first layered structure and the second layered structure are made of different materials.

[0012] In some embodiments, the first layered structure and the second layered structure each have at least one layer, and the first layered structure and the second layered structure are alternately arranged.

[0013] In some embodiments, the micro-nano structure and the surrounding materials form a superstructure unit, and the micro-nano structure is disposed at the center and / or vertex of the superstructure unit.

[0014] A second aspect of an embodiment of the present application provides a lithography machine, comprising an objective lens system, wherein the objective lens system comprises at least two reflective mirrors, and at least one of the reflective mirrors is a superlens as described in any one of the above items.

[0015] In some embodiments, the lithography machine is an extreme ultraviolet lithography machine.

[0016] In some embodiments, the micro-nano structure is a negative micro-nano structure.

[0017] The superlens provided in the present application includes a substrate, a reflecting portion and a structural surface. The substrate is used to provide support, and a reflecting portion and a structural surface are sequentially provided on the substrate. The reflecting portion is used to reflect the incident light to the structural surface. After the light is incident on the structural surface, it enters the reflecting portion, and the reflecting portion reflects the light to the structural surface. The structural surface is provided with a micro-nano structure array, and the structural surface is used to modulate the outgoing light. After the reflecting portion reflects the light to the structural surface, the light passes through the structural surface and focuses on one point. Since the structural surface and the reflecting portion are both planar structures, the superlens provided in the present application realizes the reflection function of the aspherical reflector by utilizing the structural surface on the basis of the plane reflector. Therefore, there is no need to make requirements on the surface shape of each component, so that the processing difficulty of the superlens proposed in the present application is lower than the processing difficulty of the high-precision surface reflector. Therefore, the production cost of the superlens is relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0019] Figure 1 A schematic diagram of the structure of a superlens in one embodiment of the present application is shown.

[0020] Figure 2 A top view of a structural surface in an embodiment of the present application is shown.

[0021] Figure 3 A top view of a structural surface in an embodiment of the present application is shown.

[0022] Figure 4 The figure shows a schematic structural diagram of an objective lens system of a photolithography machine in the prior art.

[0023] Figure 5 A schematic diagram of the structure of an objective lens system of a lithography machine in one embodiment of the present application is shown.

[0024] Reference numerals

[0025] 100. Super lens;

[0026] 1. Structural surface; 11. Micro-nano structure;

[0027] 2. Reflection part; 21. First layered structure; 22. Second layered structure;

[0028] 3. Base;

[0029] 1000, objective lens system; 200, reflecting mirror. DETAILED DESCRIPTION

[0030] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present application will be more comprehensive and complete and the concepts of the example embodiments will be fully conveyed to those skilled in the art. The accompanying drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0031] In addition, the described features, structures or characteristics may be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present application. However, those skilled in the art will appreciate that the technical solution of the present application may be practiced while omitting one or more of the specific details, or other modules, components, etc. may be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the present application and making the various aspects of the present application unclear.

[0032] See also Figure 1 , Figure 1A schematic structural diagram of a superlens 100 in an embodiment of the present application is shown, wherein the superlens 100 comprises a substrate 3, a reflecting portion 2 and a structural surface 1, wherein the substrate 3 is used to provide support, and the reflecting portion 2 and the structural surface 1 are sequentially arranged on the substrate 3, that is, the reflecting portion 2 is located between the structural surface 1 and the substrate 3 along the thickness direction Z.

[0033] The reflector 2 is used to reflect the incident light to the structural surface 1. Specifically, after the light is incident on the structural surface 1, it enters the reflector 2, and the reflector 2 reflects the light to the structural surface 1. It is convenient to observe the light path. Figure 1 Two different light rays are shown in the figure using solid and dotted lines respectively.

[0034] The structural surface 1 is provided with a micro-nano structure array, and the structural surface 1 is used to modulate the outgoing light. Specifically, after the reflector 2 reflects the light to the structural surface 1, the light passes through the structural surface 1 and is focused at one point. It should be noted that when the light is incident on the structural surface 1, the structural surface 1 has a modulating effect on the incident light in this process, and the modulation effect in this process includes but is not limited to focusing. That is, the structural surface 1 has a modulating effect on both the incident light and the outgoing light, and the total modulation effect of the structural surface 1 on the incident light and the outgoing light is focusing. Since the structural surface 1 and the reflector 2 are both planar structures, the super lens 100 provided in the present application uses the structural surface 1 on the basis of the plane reflector to realize the reflection function of the aspherical reflector. Therefore, the super lens 100 does not need to make requirements on the surface shape of each component, so that the processing difficulty of the super lens 100 proposed in the present application is lower than the processing difficulty of the high-precision surface reflector. Therefore, the production cost of the super lens 100 is relatively low.

[0035] The incident light of the metalens 100 may be parallel light or non-parallel light. When the incident light of the metalens 100 is non-parallel light, the incident light may be divergent light or focused light.

[0036] See also Figure 1 In some embodiments, the incident light is parallel light, the point where the light converges is the focus P of the structural surface 1, and the phase distribution of the metalens 100 satisfies:

[0037]

[0038] Wherein, λ is the wavelength of the incident light, x is the horizontal coordinate of any position on the metalens 100, and y is the vertical coordinate of any position on the metalens 100. x0 is the horizontal coordinate of the focus of the structural plane 1, and y0 is the vertical coordinate of the focus of the structural plane 1, that is, the coordinates of the focus P of the structural plane 1 are (x0, y0). f is the focal length of the structural plane 1. θ is the angle between the incident light and the structural plane 1.

[0039] For the above-mentioned micro-nano structure array, the micro-nano structure array is composed of a plurality of micro-nano structures 11 arranged in a regular pattern, and the micro-nano structure 11 is a positive micro-nano structure 11 or a negative micro-nano structure 11. It should be noted that although Figure 1 The micro-nano structure 11 shown in the figure is a negative micro-nano structure, but both positive micro-nano structures and negative micro-nano structures are within the protection scope of this application. In addition, the micro-nano structure array can be provided with one layer, two layers or more than three layers.

[0040] When the micro-nano structure 11 is a positive micro-nano structure, the positive micro-nano structure is arranged on the surface of the reflective portion 2 away from the substrate 3, and the gaps between the positive micro-nano structures are filled with air or a filling material with high transmittance in the working band. When the micro-nano structure 11 is a negative micro-nano structure, the negative micro-nano structure is a hollow portion arranged on the surface of the substrate 3, and the gaps between the hollow portions are filled with a filling material, which can be the same as the material of the substrate 3 or different from the material of the substrate 3, and the filling material has a high transmittance in the working band.

[0041] The micro-nano structure 11 and the materials around it form a superstructure unit. When the micro-nano structure 11 is a positive micro-nano structure, the positive micro-nano structure and the air or filling material around it form a superstructure unit. When the micro-nano structure 11 is a negative micro-nano structure, the negative micro-nano structure and the filling material around it form a superstructure unit. The micro-nano structure 11 is arranged at the center and / or vertex of the superstructure unit. Specifically, the position where the micro-nano structure 11 is arranged is any one of the following three situations.

[0042] (1) The micro-nano structure 11 is arranged at the center of the superstructure unit.

[0043] (2) The micro-nano structure 11 is arranged at the vertex of the superstructure unit.

[0044] (3) The micro-nano structure 11 is arranged at the center and the vertex of the superstructure unit.

[0045] See also Figure 2 In some embodiments, the superstructure unit is a regular hexagon, and the micro-nanostructure 11 is disposed at the center of the superstructure unit.

[0046] See also Figure 3 In some embodiments, the superstructure unit is square, and the micro-nanostructure 11 is disposed at the center of the superstructure unit.

[0047] See also Figure 1 For the above-mentioned reflective part 2 , the reflective part 2 includes a first layered structure 21 and a second layered structure 22 , and the first layered structure 21 and the second layered structure 22 are alternately stacked along the thickness direction Z. The first layered structure 21 and the second layered structure 22 form an interface at their junction.

[0048] The layered structure where the reflective portion 2 contacts the structural surface 1 may be a first layered structure 21 , and the layered structure where the reflective portion 2 contacts the structural surface 1 may also be a second layered structure 22 .

[0049] In the embodiment of the present application, the reflective portion 2 is formed by alternatingly stacking a first layered structure 21 and a second layered structure 22 along the thickness direction Z, that is, the layered structure where the reflective portion 2 contacts the structural surface 1 is the first layered structure 21 .

[0050] The number of layers of the reflective portion 2 can be two, three or more layers, and the specific number of layers is not limited. Figure 1 The number of layered structures of the reflecting part 2 is four, but it cannot be understood that the number of layered structures of the reflecting part 2 can only be four or can only be an even number of layers.

[0051] The refractive index of the first layered structure 21 and the refractive index of the second layered structure 22 are not equal, so that the reflective part 2 forms a Bragg reflector, which is an optical element designed according to the Bragg law, and is mainly used to achieve highly selective reflection of light within a specific wavelength range. After the light is incident on the structural surface 1, the light enters the reflective part 2, and a part of the light is reflected from the interface between the first layered structure 21 and the second layered structure 22 to the structural surface 1, and the other part of the light propagates from the interface between the first layered structure 21 and the second layered structure 22 toward the direction close to the substrate 3. When the reflective part 2 has multiple interfaces, the above process is repeated.

[0052] However, it should be noted that no matter how many interfaces the reflective portion 2 has, for the light at each interface, a portion of the light is reflected from the interface to the structural surface 1, and another portion of the light propagates from the interface toward the direction close to the substrate 3. It should be noted that most of the light is reflected to the structural surface 1 from the first interface, and part of the light is reflected to the structural surface 1 at each interface, so that less and less light is incident on the next interface, that is, most of the light is reflected to the structural surface 1. Therefore, the reflective portion 2 includes multiple layered structures to improve the utilization rate of light.

[0053] The first layered structure 21 and the second layered structure 22 are made of different materials, so that the first layered structure 21 and the second layered structure 22 can form an interface. The material of either the first layered structure 21 or the second layered structure 22 is molybdenum, and the material of the other of the first layered structure 21 and the second layered structure 22 is silicon.

[0054] In some embodiments, the reflective portion 2 includes a first layered structure 21 and a second layered structure 22 , and the two layered structures together form an interface.

[0055] In some embodiments, the reflective portion 2 includes three layered structures, specifically, the three layered structures are a first layered structure 21 and two second layered structures 22, or two first layered structures 21 and one second layered structure 22. The three layered structures are alternately arranged to form two interfaces, and the two interfaces are spaced apart along the thickness direction Z.

[0056] See also Figure 1 In the embodiment of the present application, the reflective portion 2 includes two first layered structures 21 and two second layered structures 22, and the first layered structures 21 and the second layered structures 22 are alternately arranged to form three interfaces, and the three interfaces are spaced apart along the thickness direction Z, and the three interfaces are respectively the first interface S1, the second interface S2 and the second interface S3. Figure 1 Only the refraction and reflection light paths of the light at the first interface S1 and the second interface S3 are shown. In fact, the light is also refracted and reflected at the second interface S2.

[0057] In some embodiments, the reflective portion 2 includes five or more (including five) layered structures, and the first layered structure 21 and the second layered structure 22 are alternately arranged. Specifically, since the first layered structure 21 and the second layered structure 22 are alternately arranged, the first layered structure 21 and the second layered structure 22 together form at least four interface surfaces, and the at least four interface surfaces are spaced apart along the thickness direction Z.

[0058] Since the metalens 100 provided in the present application works in a reflection mode, the provision of the substrate 3 will not affect the performance of the metalens 100. By setting a reasonable size of the substrate 3, the size of the metalens 100 can be increased, so that the metalens 100 has a larger application scenario. For example, when the metalens 100 is applied to the field of extreme ultraviolet light, the problem of the extreme ultraviolet metalens being too small in size can be solved.

[0059] In a specific embodiment, the material of the structural surface 1 and the substrate 3 of the superlens 100 are both amorphous silicon, and the first layered structure 21 and the second layered structure 22 are both film layers. The superlens 100 is processed using semiconductor technology, and when the superlens 100 is mass-produced, the production cost of a single superlens 100 can be significantly reduced.

[0060] The present application also provides a photolithography machine, which includes a light source (not shown) and an objective lens system 1000, wherein the light source is used to generate light of a specific wavelength, such as deep ultraviolet and extreme ultraviolet. Figure 4 In the prior art, the objective lens system 1000 includes at least two reflectors 200, each reflector 200 is arranged at an interval, and each reflector 200 is used to reflect light in sequence and focus the light on a point for etching.

[0061] Figure 4 FIG. 1 shows an objective lens system 1000 composed of four reflectors 200, which are arranged at intervals. The light generated by the light source is reflected to each reflector 200 in turn, and the light is reflected by the last reflector 200 and converges to a point. It should be noted that Figure 4 Only for explaining the working principle of the objective lens system 1000, the number of reflectors 200 included in the objective lens system 1000 is not limited to four. Exemplarily, the number of reflectors 200 included in the objective lens system 1000 may be two, three or more than four.

[0062] At least one reflector of the objective lens system 1000 of the lithography machine provided in the present application is the above-mentioned super lens 100. Figure 5 , Figure 5 The objective lens system 1000 shown is composed of three reflectors 200 and a super lens 100. The three reflectors 200 and the super lens 100 are arranged in sequence at intervals. The light generated by the light source is reflected onto the three reflectors 200 in sequence, and finally reflected onto the super lens 200. The super lens converges the reflected light to one point.

[0063] It should be noted that Figure 5 It is only used to illustrate the working principle of the objective lens system 1000 of the lithography machine proposed in this application, and cannot be understood as the specific structure of the objective lens system 1000 and the number of lenses included. Exemplarily, the objective lens system 1000 can also be the following structure: (1) The objective lens system 1000 includes four lenses, and the first lens through which the light generated by the light source passes is the metalens 100, and the remaining three lenses are reflectors 200. (2) The objective lens system 1000 includes six lenses, and the first and last lenses through which the light generated by the light source passes are the metalens 100, and the remaining four lenses are reflectors 200. (3) The objective lens system 1000 includes seven lenses, and all lenses of the objective lens system 1000 are metalens 100.

[0064] The objective lens system 1000 in the prior art usually includes a plurality of reflectors 200 with high surface accuracy. Since the production cost of the reflectors 200 with high surface accuracy is high, the production cost of the objective lens system 1000 of the lithography machine is high. Therefore, when at least one reflector 200 of the objective lens system 1000 of the lithography machine is the metalens 100 proposed in the present application, the production cost of the objective lens system 1000 of the lithography machine can be reduced, thereby reducing the production cost of the lithography machine.

[0065] In some embodiments, the above-mentioned lithography machine is an extreme ultraviolet lithography machine, which is also called an EUV (Extreme Ultra-violet, referred to as EUV) lithography machine. It is a lithography technology that uses extreme ultraviolet light with a wavelength of 10 to 14 nanometers as a light source. The extreme ultraviolet lithography machine can currently be used in the manufacture of advanced process chips of 14 nanometers and below.

[0066] In the prior art, the surface accuracy and surface roughness of the reflector of the objective system of the extreme ultraviolet lithography machine reach the nanometer and picometer levels respectively. Since the surface accuracy requirements of the reflector of the objective system are too high, the preparation of the reflector is difficult and the preparation cost is high. When the metalens 100 provided in the present application is applied to the objective system of the extreme ultraviolet lithography machine, the metalens 100 can replace at least one reflector of the objective system of the extreme ultraviolet lithography machine, thereby reducing the production cost of the extreme ultraviolet lithography machine.

[0067] Since general optical materials (including air) severely absorb extreme ultraviolet light, the objective system of the extreme ultraviolet lithography machine works in a vacuum environment to prevent air from absorbing extreme ultraviolet light, thereby reducing the loss of extreme ultraviolet light.

[0068] In some embodiments, the material of the structural surface 1 is amorphous silicon, and the micro-nano structure 11 is a negative micro-nano structure 11. Since the refractive index of extreme ultraviolet light in a vacuum is greater than the refractive index in silicon, and the negative micro-nano structure 11 is a hollow part, when the extreme ultraviolet light enters or exits the structural surface 1, a waveguide effect occurs. The waveguide effect refers to the phenomenon that when electromagnetic waves (such as radio waves, light waves) propagate in an environment with a specific geometric structure (such as a group of buildings, a canyon, or an artificial waveguide structure), their energy is mainly transmitted along a specific direction (waveguide path) and decays slowly. This effect is similar to the propagation of light in a physical waveguide such as an optical fiber or a metal tube, in which the energy of the wave is confined to a specific area and is transmitted over a long distance through continuous reflection. The extreme ultraviolet light passes through the structural surface 1 from the hollow part corresponding to the negative micro-nano structure 11, so that the extreme ultraviolet light does not pass through the solid part of the structural surface 1 when it enters or exits the structural surface 1, which can avoid the physical part of the structural surface 1 absorbing the extreme ultraviolet light and reduce the loss of the extreme ultraviolet light.

[0069] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. A superlens, characterized in that: include: A substrate, a reflective portion and a structural surface, wherein the reflective portion is located between the structural surface and the substrate along a thickness direction, and the structural surface is provided with a micro-nano structure array; Among them, after the light is incident on the structural surface, it enters the reflecting part; after the light is reflected by the reflecting part, it is emitted from the structural surface; the structural surface is used to converge the emitted light.

2. The metalens according to claim 1, characterized in that The point where the light converges is the focus of the structural surface, and the phase distribution of the superlens satisfies: Among them, λ is the wavelength of the incident light, x is the horizontal coordinate of any position on the metalens, and y is the vertical coordinate of any position on the metalens; x0 is the horizontal coordinate of the focus of the structural surface, y0 is the vertical coordinate of the focus of the structural surface, f is the focal length of the structural surface; θ is the angle between the incident light and the structural surface.

3. The metalens according to claim 1, characterized in that The reflective portion includes a first layered structure and a second layered structure, the first layered structure and the second layered structure are stacked in a thickness direction, and the refractive index of the first layered structure is unequal to the refractive index of the second layered structure.

4. The metalens according to claim 3, characterized in that The first layered structure and the second layered structure are made of different materials.

5. The superlens according to claim 3, characterized in that The first layered structure and the second layered structure each have at least one layer, and the first layered structure and the second layered structure are alternately arranged.

6. The superlens according to any one of claims 1 to 5, characterized in that The micro-nano structure and the surrounding materials form a super-structure unit, and the micro-nano structure is arranged at the center and / or vertex of the super-structure unit.

7. The superlens according to claim 6, characterized in that The superstructure unit is a regular hexagon or a square.

8. A photolithography machine, characterized in that: It comprises an objective lens system, wherein the objective lens system comprises at least two reflectors, and at least one of the reflectors is the metalens according to any one of claims 1 to 7.

9. The photolithography machine according to claim 8, characterized in that: The photolithography machine is an extreme ultraviolet photolithography machine.

10. The photolithography machine according to claim 9, characterized in that: The micro-nano structure is a negative micro-nano structure.

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