Superlens device and manufacturing method thereof
By forming a covering structure on the surface of the superlens structure layer and utilizing a combination of materials with different refractive indices, the problems of high light loss and high reflectivity are solved, the effect of low light loss and high luminous flux is achieved, and the light collection and focusing performance of the superlens is improved.
Patent Information
- Application Number
- CN202410397405.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-02
- Publication Date
- 2025-10-14
AI Technical Summary
Existing super lenses have high light loss and high reflectivity when light is incident, resulting in reduced resolution. Increasing the area or reducing the distance between the light source and the super lens will affect the process difficulty or focusing efficiency.
A covering structure is formed on the surface of the lens structure layer so that the refractive index of the lens structure layer is greater than the refractive index of the covering structure and the substrate. An array of columnar structures and covering structures are formed on the surface of the substrate through nanoimprint lithography and etching processes. Materials with different refractive indices are combined to reduce reflection and increase transmission.
The effects of low light loss and high light flux are achieved, and the light collection ability and focusing quality of the metalens are improved.
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Figure CN120779503A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of semiconductor technology, and in particular to a metalens device and a manufacturing method thereof. BACKGROUND
[0002] Metalenses are formed by two-dimensional structures such as nanocolumns or rings of different feature sizes arranged and combined in a certain order. They can use wavelength or nanostructures in very thin film layers to control the phase, amplitude, polarization, etc. of light, and a piece of lens can realize the combination function of multiple traditional lens groups, without the need for complex and large lens groups, so it is lighter in weight, smaller in size, and has better focusing quality.
[0003] At present, metalenses can be prepared by using mature semiconductor processes such as electron beam direct writing lithography (EBL), deep ultraviolet lithography (DUV), extreme ultraviolet lithography (EUV), etc. to form patterns on the surface of a substrate, and then transferring the structure to the substrate by etching process.
[0004] Since metalenses can achieve specific optical effects in a single layer film, when a light source is incident, most of the light will be reflected by the substrate, and a small amount of light will be absorbed by the substrate, resulting in invalid loss of the light source, which indirectly reduces the light collection ability and utilization of the metalens, resulting in a decrease in resolution. In addition, in order to make up for the light loss and improve the light collection ability, the area of the metalens can be increased or the distance between the light source and the metalens can be reduced, but the former will increase the process difficulty, and the latter will reduce the focusing efficiency.
[0005] It should be noted that the above introduction to the technical background is only to facilitate a clear and complete description of the technical solutions of the present application, and to facilitate the understanding of those skilled in the art. The above technical solutions cannot be considered as known to those skilled in the art merely because they are described in the background section of the present application. SUMMARY
[0006] In order to solve the above problems or at least similar problems, the embodiments of the present application provide a metalens device and a manufacturing method thereof. A cover structure is formed on the surface of the lens structure layer, and the refractive index of the lens structure layer is greater than the refractive index of the cover structure and also greater than the refractive index of the substrate. Thus, the effects of reducing reflection and increasing transmission (antireflection and increasing transmission), low light loss, and high light flux are achieved.
[0007] According to an aspect of an embodiment of the present application, a metalens device is provided, which includes:
[0008] a substrate, which is made of a transparent first dielectric material and has a first refractive index;
[0009] a columnar structure formed on the surface of the substrate, the columnar structure being arranged in an array on the surface of the substrate, the material of the columnar structure having a second refractive index; and
[0010] a cover structure formed on the top of the columnar structure, the cover structure being a transparent second dielectric material having a third refractive index,
[0011] the second refractive index being greater than the first refractive index, and the second refractive index being greater than the third refractive index.
[0012] In some embodiments, the surface of the cover structure is a convex curved surface.
[0013] In some embodiments, the curved surface is a hemispherical surface.
[0014] In some embodiments, the surface of the cover structure and the surface of the substrate form a disordered nanostructure.
[0015] The present application also provides a method for manufacturing a superlens device, the method comprising:
[0016] forming a structure layer on the surface of a substrate;
[0017] forming a layer of transparent second dielectric material on the surface of the structure layer;
[0018] forming a pattern layer on the surface of the second dielectric layer; and transferring the pattern of the pattern layer to the second dielectric material layer and the structure layer by an etching process, so that the structure layer becomes a columnar structure arranged in an array on the surface of the substrate, and the second dielectric material layer becomes a cover structure formed on the top of the columnar structure,
[0019] wherein the material of the substrate is a transparent first dielectric material having a first refractive index, the material of the structure layer has a second refractive index, the second dielectric material layer has a third refractive index, the second refractive index is greater than the first refractive index and the third refractive index, and the first refractive index is the same as the third refractive index.
[0020] In some embodiments, the method further comprises:
[0021] using ion bombardment to expose the surface of the substrate between the columnar structures and
[0022] the surface of the cover structure, so that the surface of the cover structure and the surface of the substrate form a disordered nanostructure.
[0023] In some embodiments, the pattern layer is formed by a nanoimprint lithography process.
[0024] In some embodiments, transferring the pattern of the pattern layer to the second dielectric material layer and the structure layer comprises:
[0025] Based on the first etching condition, removing the bottom glue of the recessed part of the pattern layer;
[0026] Based on the second etching condition, etching the second dielectric material layer exposed by the bottom of the pattern layer as a mask;
[0027] Based on the third etching condition, etching the structure layer as a mask of the remaining second dielectric material layer until the surface of the substrate is exposed.
[0028] The beneficial effects of the present application are that the covering structure is formed on the surface of the lens structure layer, and the refractive index of the lens structure layer is greater than the refractive index of the covering structure and the refractive index of the substrate, thereby having the effects of reducing reflection, increasing transmission (antireflection and increasing transmission), low light loss, and high light flux.
[0029] Specific embodiments of the present application are disclosed in detail in the following description and accompanying drawings, indicating the ways in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope to the specific embodiments described. In the scope and spirit of the appended claims and their equivalents, the embodiments of the present application include many changes, modifications and equivalents.
[0030] Features described and / or illustrated with respect to one embodiment can be used in the same or similar manner in one or more other embodiments, in combination with or in place of features in other embodiments.
[0031] It should be emphasized that the term "comprises / comprising" as used herein indicates the presence of the stated features, integers, steps or components, but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. BRIEF DESCRIPTION OF DRAWINGS
[0032] The accompanying drawings included to provide a further understanding of the embodiments of the present application and constitute a part of the specification, serve to illustrate the embodiments of the present application and, together with the written description, explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings from these drawings without creative labor. In the drawings:
[0033] Figure 1 is a schematic diagram of a manufacturing method of a superlens device of the present application;
[0034] Figure 2Fig. 1 is a schematic diagram of a process structure formed after the combination of a structure layer and a substrate (first dielectric layer) of the present application;
[0035] Figure 3 Fig. 2 is a schematic diagram of a process structure formed after the combination of a second dielectric layer and the structure layer of the present application;
[0036] Figure 4 Fig. 3 is a schematic diagram of a process structure formed after the combination of a pattern layer and the second dielectric layer of the present application;
[0037] Figure 5 Fig. 4 is a schematic diagram of a process structure formed after the exposure and curing of a nanoimprint replication plate on the pattern layer of the present application;
[0038] Figure 6 Fig. 5 is a schematic diagram of a nano-pillar array (superlens) structure formed on the pattern layer of the present application;
[0039] Figure 7 Fig. 6 is a schematic diagram of a process structure formed after the removal of the bottom glue of the pattern layer by etching of the present application;
[0040] Figure 8 Fig. 7 is a schematic diagram of a process structure formed after the etching of the second dielectric layer and obtaining a nano-pillar array (superlens) structure on the second dielectric layer by etching of the present application;
[0041] Figure 9 Fig. 8 is a schematic diagram of a process structure formed after the etching of the structure layer and obtaining a nano-pillar array (superlens) structure on the structure layer by etching of the present application;
[0042] Figure 10 Fig. 9 is a scanning electron microscope (SEM) image of a superlens plane of the present application;
[0043] Figure 11 Fig. 10 is a scanning electron microscope (SEM) image of a cross-section of a nano-pillar array structure of a superlens of the present application. DETAILED DESCRIPTION
[0044] The foregoing and other features of the present application will become apparent to those skilled in the art upon consideration of the following description of specific embodiments of the present application, taken in conjunction with the accompanying drawings. In the description of embodiments of the present application, specific terminology is employed for the sake of clarity. However, the application is not intended to be limited to the specific terminology so selected. A person skilled in the art will recognize that the principles of the present application can be employed in any number of embodiments.
[0045] In the description of the embodiments of the present application, for the convenience of description, the direction parallel to the surface of the substrate is referred to as "lateral direction", the direction perpendicular to the surface of the substrate is referred to as "vertical direction", the dimension in the "vertical direction" can be referred to as "height" or "thickness"; in the "vertical direction", the direction with the back surface of the substrate facing the surface is referred to as "up" direction, and the opposite direction of the "up" direction is referred to as "down" direction; the surface of the substrate can have a central axis parallel to the "vertical direction", the direction around the central axis is referred to as "circumferential direction", and the radial direction along the central axis is referred to as "radial direction".
[0046] It should be noted that the "up" direction and the "down" direction described above are only for the convenience of description, and do not limit the orientation or posture of the superlens device of the present application during manufacturing or use.
[0047] Embodiments
[0048] Figure 1 is a schematic diagram of a manufacturing method of the superlens device of the present application. As shown in Figure 1 , the manufacturing method of the superlens device comprises:
[0049] Operation 101, forming a structure layer on the surface of the substrate;
[0050] Operation 102, forming a transparent second medium material layer on the surface of the structure layer;
[0051] Operation 103, forming a pattern layer on the surface of the second medium layer; and
[0052] Operation 104, transferring the pattern of the pattern layer to the second medium material layer and the structure layer by an etching process, so that the structure layer becomes a columnar structure arranged in an array on the surface of the substrate, and the second medium material layer becomes a cover structure formed on the top of the columnar structure.
[0053] In the present application, the material of the substrate is a transparent first medium material with a first refractive index; the material of the structure layer has a second refractive index; the second medium material layer has a third refractive index. The second refractive index is greater than the first refractive index, and the second refractive index is greater than the third refractive index. For example, the first refractive index is equal to the third refractive index.
[0054] In the present application, the surface of the cover structure is a convex curved surface. For example, the curved surface is a hemispherical surface.
[0055] By the method of the present application, the surface of the lens structure layer is formed with a cover structure, and the refractive index of the lens structure layer is greater than the refractive index of the cover structure and also greater than the refractive index of the substrate, thereby having the effects of reducing reflection, increasing transmission (antireflection and increasing transmission), low light loss, and high light flux.
[0056] AsFigure 1 As shown, the method further includes:
[0057] Operation 105 : Bombarding the surface of the substrate and the surface of the covering structure exposed between the columnar structures with ions to form disordered nanostructures on the surface of the covering structure and the surface of the substrate.
[0058] This can further reduce the reflection of light from the surface of the cover structure and the surface of the substrate.
[0059] In the present application, the substrate is, for example, quartz, the material of the structural layer is, for example, polysilicon, and the second dielectric layer is, for example, silicon oxide.
[0060] The above-mentioned operation 101 may adopt, for example, plasma chemical deposition (ICPCVD) or other processes.
[0061] The above-mentioned operation 102 may adopt, for example, phase-chemical vapor deposition (PECVD) or other processes.
[0062] The above-mentioned operation 103 may adopt a nanoimprint lithography process, for example.
[0063] In the above-mentioned operation 104, transferring the pattern of the pattern layer to the second dielectric material layer and the structural layer includes:
[0064] Operation 1041: Based on the first etching condition, remove the primer from the recessed portion of the pattern layer until the surface of the second dielectric layer at the recessed portion is exposed;
[0065] Operation 1042: Based on the second etching conditions, using the remaining pattern layer as a mask, etching the second dielectric material layer exposed at the bottom of the pattern layer until the surface of the structural layer at the recessed portion is exposed;
[0066] Operation 1043 : Based on a third etching condition, the structure layer is etched using the remaining second dielectric material layer as a mask until the surface of the substrate is exposed.
[0067] Next, combine Figures 2-9 The specific example further illustrates the manufacturing method of the metalens device of the present application.
[0068] Step 1, structural layer forming process, corresponds to the above-mentioned operation 101:
[0069] like Figure 2 As shown, a layer of high refractive index material is deposited on the surface of the substrate 1 to form the structural layer 11, for example, by using an ICPCVD process.
[0070] Specifically, the substrate 1 is a first dielectric layer, the substrate 1 has a thickness of 700 microns, and the substrate 1 is transparent quartz with a low refractive index n = 1.45.
[0071] Specifically, the structural layer 11 is made of polysilicon with a thickness of 500 nanometers, and the polysilicon has a refractive index n = 3.43.
[0072] Step 2, a second dielectric layer forming process corresponding to operation 102 described above:
[0073] As shown in Figure 3 , a second dielectric layer 21 is formed on the surface of the structural layer 11 by chemical vapor deposition, such as a plasma enhanced chemical vapor deposition (PECVD) process.
[0074] Specifically, the second dielectric layer 21 is made of silicon oxide with a thickness of 200 nanometers, and the silicon oxide has a refractive index n = 1.45. The refractive index of the second dielectric layer 21 can be the same as that of the substrate 1.
[0075] Step 3, a pattern layer forming process corresponding to operation 103 described above:
[0076] As shown in Figures 4-6 , a nano-pillar array (superlens) pattern is prepared on the surface of the second dielectric layer 21 by using ultraviolet nano-imprint lithography process.
[0077] Step 3 can include the following processing:
[0078] ① Pretreatment: the surface of the second dielectric layer 21 is treated by using oxygen plasma (O2 Plasma) through a dry adhesive remover, to remove the organic matter on the surface and attach oxygen (polar) molecules, thereby improving the surface energy and achieving high hydrophilicity;
[0079] An example of the specific process of pretreatment is shown in Table 1:
[0080] Table 1
[0081] gas ICP Power RF Power temperature Preassure time O2 = 3000 seem 1000W 0 100℃ 10 Torr 300s
[0082] Specifically, the longer the pretreatment temperature, gas flow and processing time, the better the surface hydrophilicity of the second dielectric layer 21, and the higher the bonding force between the pattern layer 31 and the second dielectric layer 21.
[0083] ② Pattern layer preparation: as shown in Figure 4 , a 200-nanometer-thick nano-imprint lithography resist is spin-coated on the surface of the second dielectric layer 21 by spin-coating process to form a pattern layer 31.
[0084] Specifically, the pattern layer 31 prepared after spin-coating is heated at 80°C for 30 seconds.
[0085] Specifically, the nanoimprint photoresist of the pattern layer 31 is a UV imprint photoresist composed of a main resin acrylate, a photoinitiator Ir-gacure 819, an additive vinyl ether, an organic solvent, a release agent and other materials.
[0086] ③ Nanoimprint lithography: such as Figure 5 As shown in FIG, a polystyrene (PS) soft replica plate 41 with a nanocolumn (superlens) structure is placed on the surface of the pattern layer 31, and then a mechanical force is applied to the surface of the PS soft replica plate 41. Then, ultraviolet light is used to solidify the pattern layer 31. Finally, the PS soft replica plate 41 is separated from the pattern layer 31 and demolded. The pattern layer 31 with a nanocolumn (superlens) structure is replicated on the surface of the second dielectric layer 21. The result is shown in FIG. Figure 6 shown.
[0087] An example of a specific process of nanoimprinting is shown in Table 2:
[0088] Table 2
[0089] Contact Speed UV separate temperature Preassure Stamp 4 mm / s 180s 1 mm / s 25℃ 20000 Pa PS
[0090] Specifically, the PS soft replica plate 41 described in the graphic layer forming process (step 3) ② is prepared by hot stamping, and polystyrene (PS) is molded on the surface of a hard matrix nanoimprint mold. Mechanical force is applied and the PS soft replica plate 41 is obtained by curing and demolding after heating at 60° for 12 hours.
[0091] Step 4, pattern transfer process, corresponds to operation 104:
[0092] like Figures 7-9 As shown, through the etching process, the nanocolumn (superlens) structure formed in the graphic layer 31 is etched and transferred to the second dielectric layer 21 as a whole, and then etched and transferred to the structural layer 11 as a whole, and finally a nanocolumn (superlens) structure is formed in the structural layer 11.
[0093] ① Removal of the bottom glue of the pattern layer: The pattern layer 31 is thinned by etching the whole pattern layer 31 through, for example, an inductively coupled plasma (ICP) etching process. The nanoimprint glue in the recessed portion of the nanopillar array (superlens) structure of the pattern layer 31 is the bottom glue of the pattern layer 31. The bottom glue in the recessed portion of the nanopillar array (superlens) structure of the pattern layer 31 is completely etched away. After the bottom glue is removed, the surface of the second dielectric layer 21 in the recessed portion of the nanopillar array (superlens) structure of the pattern layer 31 is exposed, as shown in FIG. Figure 7 shown.
[0094] An example of a specific process for removing the bottom glue of the graphic layer is shown in Table 3:
[0095] Table 3
[0096] gas1 gas2 ICP Power RF Power Preassure time CF4 = 45 seem O2 = 10 seem 500W 100W 15 mtorr 20s
[0097] Step 2, etching of the second dielectric layer: through ICP etching process, taking the remaining pattern layer 31 as a mask, the exposed surface of the second dielectric layer 21 in the recessed position of the pattern layer 31 nanorod array (superlens) structure is etched until the second dielectric layer 21 in the recessed position of the pattern layer 31 nanorod array (superlens) structure is etched through, obtaining the nanorod array (superlens) structure of the second dielectric layer 21, so that the structure layer 11 in the recessed position of the second dielectric layer 21 nanorod array (superlens) structure is exposed to the surface, as shown in FIG. 4B. Figure 8
[0098] An example of the specific process of etching of the second dielectric layer is shown in Table 4:
[0099] Table 4
[0100] gas1 gas2 ICP Power RF Power Preassure time CHF3 = 55 seem CF4 = 15 seem 700W 200W 10 mtorr 60s
[0101] Step 3, etching of the structure layer: through ICP etching process, taking the remaining second dielectric layer 21 as a mask, the exposed surface of the structure layer 11 in the recessed position of the second dielectric layer 21 nanorod array (superlens) structure is etched until the structure layer 11 in the recessed position of the second dielectric layer 21 nanorod array (superlens) structure is etched through, finally obtaining the nanorod array (superlens) structure of the structure layer 11, so that the substrate 1 in the recessed position of the structure layer 11 nanorod array (superlens) structure is exposed to the surface, and the surface of the substrate 1 is etched, at this time the pattern layer 31 is etched completely, and as shown in FIG. 4C. Figure 9
[0102] An example of the specific process of etching of the structure layer is shown in Table 5:
[0103] Table 5
[0104] gas1 gas2 ICP Power RF Power Preassure time SF6 = 80 seem C4F8 = 35 seem 500W 150W 10 mtorr 150s
[0105] Specifically, the requirements for etching of the structure layer 11 nanorod array (superlens) structure are: the structure layer 11 nanorod array (superlens) structure morphology, height, smoothness, and angle are perfect at the same time, so that the second dielectric layer 21 in the convex position of the structure layer 11 nanorod array (superlens) structure changes from a square to a hemispherical shape.
[0106] Step 5, surface bombardment process, corresponding to operation 105:
[0107] By ICP etching process, using argon plasma (Ar Plasma) with large atomic mass to bombard the surface of the finally formed superlens structure, so that the second medium layer 21 hemispherical surface in the protruding part of the structure layer 11 nanometer pillar array (superlens) structure and the surface of the substrate 1 in the recessed part of the structure layer 11 nanometer pillar array (superlens) structure form a disordered nanostructure, further reducing its reflection to light.
[0108] The specific process of the surface bombardment process is shown in Table 6:
[0109] Table 6
[0110] gas1 ICP Power RF Power Preassure time Ar = 50 seem 1000W 300W 20 mtorr 100s
[0111] Figure 10 For the scanning electron microscope (SEM) image of the superlens plane of the present application, Figure 11 For the scanning electron microscope (SEM) image of the nanometer pillar array structure section of the superlens of the present application.
[0112] The present application uses nanoimprint lithography to prepare a small line width nanometer pillar array (superlens) pattern on a transparent substrate, taking the substrate as the first medium layer 1, and preparing a hemispherical arc on the surface of the structure layer 11 nanometer pillar structure as the second medium layer 21 to reduce reflection, and the refractive index of the structure layer 11 is much greater than that of the first medium layer 1 and the second medium layer 21 with the same refractive index to form total reflection, which has the advantages of antireflection, low light loss, high light flux, and small area superlens can still have high focusing efficiency under high numerical aperture.
[0113] The above describes the present application in combination with specific embodiments, but those skilled in the art should understand that these descriptions are exemplary and are not a limitation on the scope of protection of the present application. Those skilled in the art can make various modifications and changes to the present application according to the spirit and principles of the present application, and these modifications and changes are also within the scope of the present application.
Claims
1. A super lens device, characterized in that The super lens device comprises: A substrate (1), wherein the substrate is made of a transparent first dielectric material and has a first refractive index; A columnar structure (11) is formed on the surface of the substrate, the columnar structure is arranged in an array on the surface of the substrate, and the material of the columnar structure has a second refractive index; and A covering structure (21) is formed on the top of the columnar structure, wherein the covering structure is a transparent second dielectric material having a third refractive index. The second refractive index is greater than the first refractive index, and the second refractive index is greater than the third refractive index.
2. The super lens device according to claim 1, wherein The surface of the covering structure is an upwardly convex curved surface.
3. The super lens device according to claim 2, wherein The curved surface is a hemispherical surface.
4. The super lens device according to any one of claims 1 to 3, wherein A disordered nanostructure is formed on the surface of the covering structure and the surface of the substrate.
5. A method for manufacturing a super lens device, characterized in that: The method comprises: forming a structural layer on a surface of a substrate; forming a transparent second dielectric material layer on the surface of the structural layer; forming a pattern layer on a surface of the second dielectric layer; and The pattern of the pattern layer is transferred to the second dielectric material layer and the structural layer through an etching process, so that the structural layer becomes a columnar structure arranged in an array on the surface of the substrate, and the second dielectric material layer becomes a covering structure formed on top of the columnar structure. in, The substrate is made of a transparent first dielectric material having a first refractive index. The material of the structural layer has a second refractive index, The second dielectric material layer has a third refractive index, The second refractive index is greater than the first refractive index, and the second refractive index is greater than the third refractive index.
6. The method according to claim 5, wherein The method further comprises: The surface of the substrate and the surface of the covering structure exposed between the columnar structures are bombarded with ions, so that disordered nanostructures are formed on the surfaces of the covering structure and the substrate.
7. The method according to claim 5, wherein The pattern layer is formed by adopting a nanoimprint lithography process.
8. The method according to claim 5, wherein Transferring the pattern of the pattern layer to the second dielectric material layer and the structural layer, comprising: Based on the first etching condition, removing the primer from the recessed portion of the pattern layer; Based on the second etching condition, using the remaining pattern layer as a mask, etching the second dielectric material layer exposed at the bottom of the pattern layer; Based on the third etching condition, the structural layer is etched using the remaining second dielectric material layer as a mask until the surface of the substrate is exposed.
9. The method according to claim 5, wherein The surface of the covering structure is an upwardly convex curved surface.
10. The method according to claim 9, wherein The curved surface is a hemispherical surface.