A method for fabricating a metasurface lens and the metasurface lens

Abstract

This invention discloses a method for fabricating a metasurface lens and a metasurface lens, relating to the field of metasurface lens technology. The method includes: acquiring a metasurface lens image; dividing the metasurface lens image according to a preset size to obtain at least two sub-images and a mask set corresponding to each sub-image; performing image transfer on a first wafer using the at least two sub-images and the mask set corresponding to each sub-image to obtain a second wafer carrying the metasurface lens image; and performing lens fabrication processing on the second wafer to obtain the metasurface lens. Through this method, this invention can improve efficiency and reduce costs while meeting optical performance requirements.

Description

Technical Field

[0001] This invention relates to the field of metasurface lens technology, and specifically to a method for fabricating a metasurface lens and a metasurface lens. Background Technology

[0002] Metasurface lenses are ultrathin two-dimensional arrays composed of a series of subwavelength artificial microstructures. They are relatively simple to fabricate, have relatively low loss, small size, and thinness, enabling effective control over the amplitude, phase, propagation mode, and polarization state of electromagnetic waves. Compared to conventional multi-element objectives or self-focusing lenses, metasurface lenses have unique advantages. They are significantly smaller, thinner, and lighter than other types of lenses, while still achieving a large numerical aperture.

[0003] In the existing metasurface lens fabrication process, electron beam lithography (EBL) and step-scan lithography systems are commonly used. However, if large patterns are made using electron beam lithography systems, there will be disadvantages such as low efficiency and high cost.

[0004] Step-scan lithography systems are hybrid systems that combine scanning projection lithography and step-repeat lithography technologies. They achieve this by using a shrinking lens to scan a large exposure field image onto a portion of the wafer. The standard exposure size for this type of lithography machine is 26mm × 33mm. However, when the product pattern is larger than this size, although the wafer for fabricating metasurface lenses can meet the size requirements, the maximum exposure field of view of the lithography machine is insufficient for fabricating large-patterned metasurface lenses. Due to the limitations of the maximum exposure field of view of the lithography machine and nanoimprint lithography equipment, a complete large metasurface lens feature pattern cannot be transferred to the wafer in a single exposure or imprint. In this case, it is necessary to cut out the metasurface lens sub-patterns obtained from multiple exposures or imprints, and then sequentially assemble the cut modules according to the design of the metasurface lens surface. However, this splicing method has a large splicing tolerance, which reduces the optical performance of the assembled metasurface lens.

[0005] Therefore, how to provide an efficient, low-cost method for fabricating metasurface lenses that meets optical performance requirements is a problem that urgently needs to be solved by those in the field. Summary of the Invention

[0006] To address the aforementioned problems, an embodiment of the present invention provides a method for fabricating a metasurface lens and a metasurface lens.

[0007] According to one aspect of the present invention, a method for fabricating a metasurface lens is provided, comprising:

[0008] Acquire images of metasurface lenses;

[0009] The metasurface lens image is divided according to a preset size to obtain at least two sub-images and a mask group corresponding to each sub-image;

[0010] Image transfer is performed on the first wafer using the at least two sub-images and the mask set corresponding to each sub-image to obtain a second wafer with the metasurface lens image;

[0011] The second wafer is subjected to lens fabrication to obtain a metasurface lens.

[0012] Optionally, the metasurface lens image is divided according to a preset size to obtain at least two sub-images and a mask group corresponding to each sub-image, including:

[0013] The metasurface lens image is divided according to a preset size to obtain at least two sub-images;

[0014] Based on the at least two sub-images, a mask set corresponding to each sub-image is created. If there is a common image among the at least two sub-images, a mask set is created based on the common image as the mask set corresponding to the common image.

[0015] Optionally, image transfer is performed on the first wafer using the at least two sub-images and the mask set corresponding to each sub-image to obtain a second wafer with the metasurface lens image, including:

[0016] The mask group is arranged according to the metasurface lens image to obtain the arranged image mask group;

[0017] The first wafer is image transferred according to the arranged image mask group to obtain the second wafer.

[0018] Optionally, after arranging the mask groups, the following may also be included:

[0019] If a mask group corresponds to at least two identical sub-images, then when transferring images on the first wafer, the images are transferred separately through the mask groups corresponding to the at least two identical sub-images in a preset order.

[0020] Optionally, after performing image transfer through the mask groups corresponding to the at least two identical sub-images in a preset order, the method further includes:

[0021] If the masks corresponding to the at least two identical sub-images have an angular deviation during image transfer, the masks or wafers corresponding to the at least two identical sub-images are rotated until the angular deviation is eliminated, and the images are transferred in the preset order.

[0022] Optionally, the second wafer is subjected to lens fabrication processing to obtain a metasurface lens, including:

[0023] The second wafer is developed, etched, cleaned, and coated to obtain the third wafer;

[0024] The third wafer is divided according to the preset size to obtain at least two sub-wafers;

[0025] The at least two sub-wafers are stitched together according to the metasurface lens image to obtain the metasurface lens.

[0026] Optionally, the at least two sub-wafers are stitched together according to the metasurface lens image to obtain the metasurface lens, including:

[0027] Based on the metasurface lens image, the optimal modulation transfer function of each pair of adjacent sub-wafers in the at least two sub-wafers is determined by active alignment.

[0028] Based on the optimal modulation transfer function, the at least two sub-wafers are spliced ​​together to obtain the metasurface lens.

[0029] Optionally, after obtaining at least two sub-wafers, the process may also include:

[0030] According to the metasurface lens image, the at least two sub-wafers are spliced ​​together to obtain a spliced ​​transition lens;

[0031] Measure the aberrations of the transition lens, and design a compensation lens based on the aberrations;

[0032] The compensation lens is combined with the transition lens to obtain the metasurface lens.

[0033] According to another aspect of the present invention, a metasurface lens is provided, which is manufactured by the metasurface lens manufacturing method described in any of the preceding claims.

[0034] According to the solution provided in the above embodiments of the present invention, by acquiring a metasurface lens image; dividing the metasurface lens image according to a preset size to obtain at least two sub-images and a mask group corresponding to each sub-image; performing image transfer on a first wafer through the at least two sub-images and the mask group corresponding to each sub-image to obtain a second wafer with the metasurface lens image; and performing lens fabrication processing on the second wafer to obtain a metasurface lens, efficiency is improved and cost is reduced while meeting optical performance requirements.

[0035] The above description is merely an overview of the technical solutions of the embodiments of the present invention. In order to better understand the technical means of the embodiments of the present invention and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of the present invention more obvious and understandable, specific implementation methods of the embodiments of the present invention are described below. Attached Figure Description

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0037] Figure 1 A flowchart of the metasurface lens fabrication method provided in an embodiment of the present invention is shown;

[0038] Figure 2 This diagram illustrates a specific exposure pattern of a superlens provided in an embodiment of the present invention.

[0039] Figure 3 This illustration shows a specific sub-module diagram of a graphic after software processing, provided by an embodiment of the present invention.

[0040] Figure 4 This illustration shows a specific photolithography or nanoimprinting mask fabricated based on the results of software processing, according to an embodiment of the present invention.

[0041] Figure 5 This illustration shows a specific example of pattern transfer of a photomask using a stepper or nanoimprint lithography on an entire wafer, according to an embodiment of the present invention.

[0042] Figure 6 This illustration shows a specific example of a series of splicing sub-modules obtained by cutting a pattern transferred onto a wafer, according to an embodiment of the present invention.

[0043] Figure 7 This illustration shows a specific process diagram of splicing a complete metasurface lens on a splicing substrate using an active alignment process, according to an embodiment of the present invention.

[0044] Figure 8 This illustration shows a schematic diagram of a complete metasurface lens assembled according to a design pattern using cut sub-modules provided by an embodiment of the present invention;

[0045] Figure 9 This diagram illustrates a specific metasurface lens design function provided by an embodiment of the present invention.

[0046] Figure 10 This illustration shows a specific metasurface lens fabricated by splicing according to an embodiment of the present invention;

[0047] Figure 11 This illustration shows a specific embodiment of the present invention, which involves fabricating a compensation lens from a spliced ​​metasurface lens, assembling a module to calibrate the metasurface lens, and then modulating the light source to achieve the desired effect.

[0048] Figure 12 This diagram illustrates a specific metasurface lens pattern processing and splitting method provided by an embodiment of the present invention.

[0049] Figure 13 This diagram illustrates a specific graphic transfer template creation method provided by an embodiment of the present invention.

[0050] Figure 14 This diagram illustrates a specific manufacturing process logic diagram for a single design graphic.

[0051] Figure 15 This illustration shows a specific logic diagram of mass production on an entire wafer, provided by an embodiment of the present invention. Detailed Implementation

[0052] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0053] Figure 1 A flowchart illustrating the metasurface lens fabrication method provided in an embodiment of the present invention is shown. Figure 1 As shown, the method includes the following steps:

[0054] Step 11: Obtain the image of the metasurface lens;

[0055] Step 12: Divide the metasurface lens image according to a preset size to obtain at least two sub-images and a mask group corresponding to each sub-image;

[0056] Step 13: Perform image transfer on the first wafer using the at least two sub-images and the mask set corresponding to each sub-image to obtain a second wafer with the metasurface lens image;

[0057] Step 14: Perform lens fabrication on the second wafer to obtain a metasurface lens.

[0058] In this embodiment, an image of a metasurface lens is acquired; the metasurface lens image is divided according to a preset size to obtain at least two sub-images and a mask set corresponding to each sub-image; an image transfer is performed on a first wafer using the at least two sub-images and the mask set corresponding to each sub-image to obtain a second wafer with the metasurface lens image; and lens fabrication processing is performed on the second wafer to obtain a metasurface lens. This improves efficiency and reduces cost while meeting optical performance requirements.

[0059] In an optional embodiment of the present invention, step 12 may include:

[0060] Step 121: Divide the metasurface lens image according to a preset size to obtain at least two sub-images;

[0061] Step 122: Based on the at least two sub-images, create a mask set corresponding to each sub-image. If there is a common image among the at least two sub-images, then create a mask set based on the common image as the mask set corresponding to the common image.

[0062] In this embodiment, creating a set of masks for the same image can reduce production costs and improve efficiency.

[0063] In another optional embodiment of the present invention, step 13 may include:

[0064] Step 131: Arrange the mask group according to the metasurface lens image to obtain the arranged image mask group;

[0065] Step 132: Perform image transfer on the first wafer according to the arranged image mask group to obtain the second wafer.

[0066] In step 131, after arranging the mask group, the following is also included:

[0067] Step 133: If the mask group corresponds to at least two identical sub-images, then when performing image transfer on the first wafer, the image transfer is performed respectively through the mask group corresponding to the at least two identical sub-images in a preset order.

[0068] In step 133, after image transfer is performed in a preset order using the mask groups corresponding to the at least two identical sub-images, the method further includes:

[0069] Step 134: If the masks corresponding to the at least two identical sub-images have an angular deviation during image transfer, the masks or wafers corresponding to the at least two identical sub-images are rotated until the angular deviation is eliminated, and the images are transferred in the preset order.

[0070] In yet another optional embodiment of the invention, step 14 may include:

[0071] Step 141: The second wafer is developed, etched, cleaned, and coated to obtain the third wafer;

[0072] Step 142: Divide the third wafer according to the preset size to obtain at least two sub-wafers;

[0073] Step 143: The at least two sub-wafers are spliced ​​together according to the metasurface lens image to obtain the metasurface lens.

[0074] The procedure following step 142 may further include:

[0075] Step 1421: According to the metasurface lens image, the at least two sub-wafers are spliced ​​together to obtain a spliced ​​transition lens;

[0076] Step 1422: Measure the aberration of the transition lens, and design a compensation lens based on the aberration;

[0077] Step 1423: Combine the compensation lens with the transition lens to obtain the metasurface lens.

[0078] Step 143 may also include:

[0079] Step 1431: Based on the metasurface lens image, determine the optimal modulation transfer function for each pair of adjacent sub-wafers in the at least two sub-wafers by active alignment.

[0080] Step 1432: According to the optimal modulation transfer function, the at least two sub-wafers are spliced ​​together to obtain the metasurface lens.

[0081] Figures 2 to 7 This invention illustrates a specific method for fabricating a large metasurface lens based on an active alignment (AA) process. Active alignment (AA) involves simultaneously testing the assembled semi-finished product with light or electricity during the assembly of each component. Based on the test results, active alignment is performed, and then two or more components are assembled into their final positions. This active alignment technology effectively reduces the assembly tolerance of the entire module, significantly improves the consistency of camera products, and creates possibilities for packaging higher-end camera products, such as… Figures 2 to 7 As shown, the method includes:

[0082] Step 1: Perform image processing on the design file of the large metasurface lens pattern, extract the areas with the same pattern and divide them into several sub-modules with a size of less than or equal to 26mm×33mm. For the repeated sub-modules, only one corresponding photolithography mask or nanoimprint template needs to be made. For the other pattern areas without repetition, graphic transfer templates are also made separately.

[0083] Step 2: The mobile platform first moves to the starting graphic transfer position, uses the mask created in Step 1 for the current position, and performs exposure or imprinting. Imprinting refers to graphic transfer. The software for splitting the exposed graphic can be developed using any programming tool or graphics processing tool.

[0084] Step 3: Move the platform to the next graphic transfer position, and repeat Step 2 to complete the graphic transfer at that position;

[0085] Step four, repeat step three until the graphic transfer of the mask pattern across the entire substrate is complete;

[0086] Step 5: Switch the mask or use a mask pattern at a different location on the same mask, move to the next exposure position, and repeat steps 2 to 4 to complete the pattern transfer of the mask pattern across the entire substrate.

[0087] Step six, repeat step five until the graphic transformation of all the required sub-modules for splicing is completed;

[0088] Step 7: Perform subsequent processes such as development and etching on the substrate with the completed pattern transfer to obtain a sub-module of a large metasurface lens structure.

[0089] Step 8: Cut the metasurface lens sub-modules on the substrate sequentially to obtain several independent sub-modules;

[0090] Step 9: The cut sub-modules are spliced ​​on the substrate according to the pattern design. During splicing, AA is performed to determine the optimal combination of modulation transfer functions between two adjacent sub-modules. The modulation transfer function (MTF) is a more scientific method for analyzing the resolution of the lens, and the MTF imaging curve is the most authoritative and objective technical reference for the imaging quality of the lens.

[0091] Step 10: Repeat step 9, AA-ing the remaining cut sub-modules separately and then splicing them together until a complete metasurface lens is assembled.

[0092] The invention will be further described below with reference to the accompanying drawings and the specific method for fabricating large metasurface lenses based on the active alignment process described above:

[0093] The first, third, and fifth embodiments are fabrications of large metasurface lenses using a step-scan lithography system, while the second, fourth, and sixth embodiments are fabrications of large metasurface lenses using a step-nanoimprint system.

[0094] First embodiment:

[0095] like Figure 2 As shown, the circular region S is the designed metasurface lens pattern area, which is larger than the exposure field of view of the stepper lithography machine, which is 26mm × 33mm.

[0096] like Figure 3 As shown, the present invention uses software processing to divide the graphic into several sub-modules smaller than 26mm × 33mm, where A1, A2, A3 and A4 are completely identical graphics, and B1, B2, B3, B4, B5 and B6 are completely identical graphics.

[0097] like Figure 4 As shown, a photomask is fabricated using electron beam lithography or mechanical processing based on the results of software processing. If there are identical sub-modules, only one photomask needs to be fabricated. Depending on the size of the sub-module pattern, multiple sub-module patterns can be designed onto the same photomask. The patterns obtained by exposing the fabricated photomask are U1 and U2, where U1 contains pattern A1 and can be used to fabricate modules A1, A2, A3 and A4, and U2 contains pattern B1 and can be used to fabricate modules B1, B2, B3, B4, B5 and B6.

[0098] like Figure 5 As shown, the fabricated mask U1 is installed on the stepper lithography system. The stage of the stepper scanning lithography system, on which the pre-treated substrate is placed, is moved to the initial position for exposure to obtain the exposure area U1, corresponding to pattern A1. The platform is then moved to the next exposure position for exposure, and this process is repeated to complete the exposure of the current mask on the substrate. The exposure mask U2 is then switched, and the substrate is changed for stepper exposure to complete the exposure of the current mask on the substrate. Depending on the number of sub-modules required, multiple sub-module patterns can also be exposed on the same substrate by changing the mask midway, thus achieving the exposure of multiple sub-module patterns on a single wafer.

[0099] like Figure 6 As shown, after the substrate with the pattern transfer is subjected to subsequent development, etching and other processes, several sub-module patterns for splicing are obtained. The sub-modules are then cut from the substrate to obtain the splicing sub-modules.

[0100] like Figure 7As shown, on the splicing substrate U5, according to the pattern design, two adjacent sub-modules obtained by cutting are subjected to AA (analysis). After obtaining the optimal MTF, the two sub-modules are spliced ​​together. Then, the next adjacent sub-module is subjected to AA with the spliced ​​module. After obtaining the optimal MTF, the two modules are spliced ​​together. This process is repeated until a complete metasurface lens is obtained on the substrate.

[0101] Second embodiment:

[0102] like Figure 2 As shown, the circular region S is the designed metasurface lens pattern region, and the area of ​​this region is larger than the pattern area produced by a single imprinting of the high-resolution nanoimprinting system.

[0103] like Figure 3 As shown, the present invention uses software processing to divide the graphic into several sub-modules smaller than the word imprinting area of ​​the nanoimprinting system, wherein A1, A2, A3 and A4 are completely identical graphics, and B1, B2, B3, B4, B5 and B6 are completely identical graphics.

[0104] like Figure 4 As shown, photolithography masks are fabricated using electron beam lithography or mechanical processing based on the results of software processing. If there are identical sub-modules, only one mask needs to be fabricated. Depending on the size of the sub-module pattern, multiple sub-module patterns can be designed onto the same mask. The fabricated nanoimprint masks are U1 and U2, where U1 contains pattern A1 and can fabricate modules A1, A2, A3 and A4, and U2 contains pattern B1 and can fabricate modules B1, B2, B3, B4, B5 and B6.

[0105] like Figure 5 As shown, a large imprinting template U1B is fabricated using the U1 imprinting mask, which can imprint multiple A1 patterns at once. Similarly, a large imprinting template U2B is fabricated using the U2 imprinting mask, which can also imprint multiple A1 patterns at once. The fabricated U1B mask is installed on the nanoimprinting system. The nanoimprinting stage, with the pre-treated substrate placed on it, is moved to its initial position, and imprinting is performed to obtain the imprinting area U1, corresponding to the pattern A1, thus determining the expected number of A1 modules. The U2B mask is then switched, and the substrate is changed for imprinting, completing the imprinting of the current mask on that substrate. Depending on the required number of sub-modules, multiple smaller templates can also be integrated on the same large template for imprinting, enabling the imprinting of multiple sub-module patterns on a single wafer.

[0106] like Figure 6 As shown, after the substrate with the pattern transfer is subjected to subsequent development, etching and other processes, several sub-module patterns for splicing are obtained. The sub-modules are then cut from the substrate to obtain the splicing sub-modules.

[0107] like Figure 7 As shown, on the splicing substrate U5, according to the pattern design, two adjacent sub-modules obtained by cutting are subjected to AA (analysis). After obtaining the optimal MTF, the two sub-modules are spliced ​​together. Then, the next adjacent sub-module is subjected to AA with the spliced ​​module. After obtaining the optimal MTF, the two modules are spliced ​​together. This process is repeated until a complete metasurface lens is obtained on the substrate.

[0108] In this method for fabricating large metasurface lenses based on an active alignment process, the first and second embodiments described above reduce costs and improve efficiency compared to other exposure methods for fabricating large metasurface lens patterns. Active alignment during splicing effectively reduces the assembly tolerance of the entire lens, making it easier to promote and apply in industry. The fabrication process is simple, enabling low-cost fabrication of large metasurface lens structures and effectively reducing assembly tolerances during assembly. This provides a new low-cost, large-scale fabrication technology for large metasurface lens structures.

[0109] Figures 2 to 6 as well as Figures 8 to 11 This invention illustrates a specific method for fabricating a large metasurface lens based on one-time programmable (OTP) technology. OTP technology addresses the issue that camera modules exhibit variations in aberrations and shading due to various factors. Using the same set of parameters to calibrate lens aberrations and shading often yields unsatisfactory results. If each module undergoes lens shading calibration at the factory, and these calibration parameters are burned into the OTP, then clients only need to read these parameters from the OTP and apply them to the image, resulting in highly consistent imaging effects. Alternatively, after calibrating the module, a corresponding compensation lens can be fabricated, and the module can be integrated with the lens to complete the compensation process. Figures 2 to 6 as well as Figures 8 to 11 As shown, in this method, steps eleven to eighteen are the same as steps one to eight of the above-described method for fabricating large metasurface lenses based on an active alignment process. The specific method is as follows:

[0110] Step 11: Perform image processing on the design file of the large metasurface lens pattern, extract the areas with the same pattern and divide them into several sub-modules with a size of less than or equal to 26mm×33mm. For the repeated sub-modules, only one corresponding photolithography mask or nanoimprint template needs to be made. For the other pattern areas without repetition, pattern transfer templates are also made separately.

[0111] Step 12: The mobile platform first moves to the starting graphic transfer position, uses the mask created in Step 11 for the current position, and performs exposure or imprinting. Imprinting refers to graphic transfer. The software for splitting the exposed graphic can be developed using any programming tool or graphics processing tool.

[0112] Step 13: Move the platform to the next graphic transfer position and repeat Step 12 to complete the graphic transfer at that position;

[0113] Step fourteen: Repeat step thirteen until the graphic transfer of the mask pattern across the entire substrate is complete;

[0114] Step 15: Switch the mask or use a mask pattern at a different location on the same mask, move to the next exposure position, and repeat steps 12 to 14 to complete the pattern transfer of the mask pattern across the entire substrate.

[0115] Step 16: Repeat step 15 until the graphic transformation of all required sub-modules for splicing is completed;

[0116] Step 17: Perform subsequent processes such as development and etching on the substrate with the completed pattern transfer to obtain a sub-module of a large metasurface lens structure.

[0117] Step 18: Cut the metasurface lens sub-modules on the substrate sequentially to obtain several independent sub-modules;

[0118] Step 19: Assemble the cut sub-modules according to the pattern design to obtain a complete large metasurface lens;

[0119] Step 20: Measure and observe the aberrations of the metasurface lens, and design an OTP compensation lens based on the measured aberrations to compensate for the aberrations of the metasurface lens.

[0120] Step 21: Combine the metasurface lens and the OTP compensation lens to form a module.

[0121] The present invention will be further described below with reference to the accompanying drawings and the specific method for fabricating large metasurface lenses based on OTP technology described above. In particular, in... Figure 8 In the diagram, U5 is the substrate used for splicing; Figure 9 The diagram shows the theoretical effect that light source L should have after being modulated by the metasurface lens, with S1 being the side surface of the metasurface lens S. The light source can be visible light, infrared light, or any light designed by the metasurface lens for modulation, and the modulation effect is not limited to the example shown in the diagram.

[0122] Third embodiment:

[0123] like Figure 2As shown, the circular region S is the designed metasurface lens pattern area, which is larger than the exposure field of view of the stepper lithography machine, which is 26mm × 33mm.

[0124] like Figure 3 As shown, the present invention uses software processing to divide the graphic into several sub-modules smaller than 26mm × 33mm, where A1, A2, A3 and A4 are completely identical graphics, and B1, B2, B3, B4, B5 and B6 are completely identical graphics.

[0125] like Figure 4 As shown, a photomask is fabricated using electron beam lithography or mechanical processing based on the results of software processing. If there are identical sub-modules, only one photomask needs to be fabricated. Depending on the size of the sub-module pattern, multiple sub-module patterns can be designed onto the same photomask. The patterns obtained by exposing the fabricated photomask are U1 and U2, where U1 contains pattern A1 and can be used to fabricate modules A1, A2, A3 and A4, and U2 contains pattern B1 and can be used to fabricate modules B1, B2, B3, B4, B5 and B6.

[0126] like Figure 5 As shown, the fabricated mask U1 is installed on the stepper lithography system. The stage of the stepper scanning lithography system, on which the pre-treated substrate is placed, is moved to the initial position for exposure to obtain the exposure area U1, corresponding to pattern A1. The platform is then moved to the next exposure position for exposure, and this process is repeated to complete the exposure of the current mask on the substrate. The exposure mask U2 is then switched, and the substrate is changed for stepper exposure to complete the exposure of the current mask on the substrate. Depending on the number of sub-modules required, multiple sub-module patterns can also be exposed on the same substrate by changing the mask midway, thus achieving the exposure of multiple sub-module patterns on a single wafer.

[0127] like Figure 6 As shown, after the substrate with the pattern transfer is subjected to subsequent development, etching and other processes, several sub-module patterns for splicing are obtained. The sub-modules are then cut from the substrate to obtain the splicing sub-modules.

[0128] like Figure 8 As shown, after the cut sub-modules are spliced ​​on the splicing substrate according to the pattern design, a complete metasurface lens is obtained.

[0129] The obtained metasurface lens is processed by programming its aberrations and lens shading calibration parameters, and then applying these parameters to the displayed image, or as... Figure 11 As shown, a method of fabricating a disposable compensation lens and combining it with a module for compensation is used to obtain a complete metasurface lens that is fabricated and compensated through splicing.

[0130] Fourth embodiment:

[0131] like Figure 2 As shown, the circular region S is the designed metasurface lens pattern area, and the area of ​​this region is larger than the area of ​​the pattern created by the high-resolution nanoimprint system.

[0132] like Figure 3 As shown, the present invention uses software processing to divide the graphic into several sub-modules smaller than the word imprinting area of ​​the nanoimprinting system, wherein A1, A2, A3 and A4 are completely identical graphics, and B1, B2, B3, B4, B5 and B6 are completely identical graphics.

[0133] like Figure 4 As shown, photolithography masks are fabricated using electron beam lithography or mechanical processing based on the results processed by the software. If there are identical sub-modules, only one mask needs to be fabricated. Depending on the size of the sub-module pattern, multiple sub-module patterns can be designed onto the same mask. The fabricated nanoimprint masks are U1 and U2, where U1 contains pattern A1 and can fabricate modules A1, A2, A3 and A4, and U2 contains pattern B1 and can fabricate modules B1, B2, B3, B4, B5 and B6.

[0134] like Figure 5 As shown, the fabricated U1 mask is installed on the nanoimprint lithography system. The nanoimprint stage with the pre-treated substrate is moved to the initial position and imprinted to obtain the imprinted area U1, corresponding to the pattern A1. The platform is moved to the next imprinting position and imprinted again. This process is repeated until the current mask is imprinted on the substrate, obtaining the expected number of A1 modules. The U2 mask is then switched, and the substrate is changed for imprinting, completing the imprinting of the current mask on the substrate. Depending on the requirements for the number of sub-modules, imprinting can also be performed on the same substrate by changing the mask midway, realizing the imprinting of multiple sub-module patterns on a single wafer.

[0135] like Figure 6 As shown, after the substrate with the pattern transfer is subjected to subsequent development, etching and other processes, several sub-module patterns for splicing are obtained. The sub-modules are then cut from the substrate to obtain the splicing sub-modules.

[0136] like Figure 8 As shown, after the cut sub-modules are spliced ​​on the splicing substrate according to the pattern design, a complete metasurface lens is obtained.

[0137] The obtained metasurface lens is processed by programming its aberrations and lens shading calibration parameters, and then applying these parameters to the displayed image, or as... Figure 11As shown, a method of fabricating a disposable compensation lens and combining it with a module for compensation is used to obtain a complete metasurface lens that is fabricated and compensated through splicing.

[0138] In this method for fabricating large metasurface lenses based on OTP technology, the third and fourth embodiments have simple fabrication processes, realize low-cost fabrication of large metasurface lens structures, and compensate for the performance reduction of the fabricated metasurface lenses caused by splicing tolerances, thus providing a new low-cost large-scale fabrication technology for large metasurface lens structures.

[0139] Figures 12 to 15 This invention illustrates a method for fabricating large metasurface lenses by splicing elements, as provided in an embodiment of the present invention. Figure 12 The central circle S is the pattern area, which can be divided into four areas: A, A', B, and C. The patterns in areas A and A' are repeated and symmetrical about the center of the pattern. The patterns in areas A, B, and C are all different. Figure 13 Three exposure masks or nanoimprint templates U1, U2 and U3 used in step scanning lithography are fabricated. The size of the pattern transfer area corresponding to the template is 26mm×33mm, and they contain patterns A, B and C respectively. Figure 15 In this context, U5 represents a wafer used for pattern transfer, which can be a silicon wafer, a glass wafer, or any substrate used to fabricate metasurface lenses; U6 represents an exposure area shot on this wafer; the method includes:

[0140] Step 22: Perform image processing on the design file of the large metasurface lens pattern, extract the areas with the same pattern and divide them into several sub-modules with a size of less than or equal to 26mm×33mm. For the repeated sub-modules, only one corresponding photolithography mask or nanoimprint template needs to be made. For the other pattern areas without repetition, pattern transfer templates are also made separately.

[0141] Step 23: The mobile platform first moves to the starting graphic transfer position, uses the mask at the current position created in step 22 and exposes or imprints it. Imprinting refers to graphic transfer. The software for splitting the exposed graphic can be developed using any programming tool or graphics processing tool.

[0142] In step 24, if the submodule in step 23 has a repetitive area in the complete pattern, move the platform to the next graphic transfer position. If there is an angular deviation between the pattern at this position and the pattern at the previous exposure position, rotate the worktable angle to make the sub-template match the pattern at the exposure position, and complete the graphic transfer at this position.

[0143] Step 25: Repeat step 24 until the mask pattern has been transferred across the entire substrate.

[0144] Step 26: Switch the mask or use a mask pattern at a different location on the same mask, move to the next exposure position, and repeat steps 23 to 25 to complete the transfer of the mask pattern across the entire substrate.

[0145] Step 27: Repeat step 26 until the graphic transfer of the entire base is complete;

[0146] Step 28: The substrate with the completed pattern transfer is subjected to subsequent processes such as development and etching to obtain a large-area metasurface lens structure.

[0147] The present invention will be further described below with reference to the accompanying drawings and the specific method for fabricating large metasurface lenses by splicing together described above:

[0148] Fifth embodiment:

[0149] like Figure 12 As shown, the circle S with a diameter of 50mm is the designed metasurface lens pattern area. In this invention, the designed metasurface lens pattern S is first processed by software and divided into four regions: A, A', B, and C. The patterns in regions A and A' are repeated and symmetrical about the center of the pattern. The patterns in regions A, B, and C are all different and the size of each pattern is less than or equal to 26mm × 33mm.

[0150] like Figure 13 As shown, the present invention uses electron beam lithography or mechanical processing to fabricate photomasks for the stepper lithography scanning system for the divided pattern areas. Only one mask needs to be fabricated for the repeated pattern areas, resulting in three exposure masks for stepper lithography. The corresponding patterns obtained by exposing the fabricated masks are U1, U2 and U3, with an exposure field size of 26mm×33mm, which respectively contain patterns A, B and C.

[0151] like Figure 14 As shown, first, install the mask corresponding to U1, move the stage of the stepper scanning lithography system with the pre-treated substrate to the initial position, and perform exposure to obtain the exposure area U1, corresponding to pattern A. Move the platform to the exposure position of pattern A', and rotate the stage 180° to perform exposure to obtain pattern A'. Switch to the exposure mask corresponding to U2, move the platform to the exposure position of pattern B, and perform exposure to obtain the exposure area U2, corresponding to pattern B. Switch to the exposure mask corresponding to U3, move the platform to the exposure position of pattern C, and perform exposure.

[0152] After several exposures and stitching, the substrate undergoes subsequent development, etching, and other processes to obtain multiple complete S-patterns on the substrate.

[0153] Sixth embodiment:

[0154] like Figure 12As shown, the circle S with a diameter of 50mm is the designed metasurface lens pattern area. In this invention, the designed metasurface lens pattern S is first processed by software and divided into four regions: A, A', B, and C. The patterns in regions A and A' are repeated and symmetrical about the center of the pattern. The patterns in regions A, B, and C are all different and the size of each pattern is less than or equal to 26mm × 33mm.

[0155] like Figure 13 As shown, the present invention uses electron beam lithography or mechanical processing to create nanoimprint stencils for the divided pattern areas. Only one mask is needed for the repeated pattern areas, resulting in three nanoimprint stencils with a size of 26mm×33mm. The corresponding patterns obtained by imprinting using the prepared masks are U1, U2 and U3, which respectively contain patterns A, B and C.

[0156] like Figure 14 As shown, first, install the mask corresponding to U1, move the stage of the stepper nanoimprint system with the pre-treated substrate to the initial position, and imprint to obtain pattern area U1, corresponding to pattern A. Move the platform to the position of pattern A', and rotate the stage 180° to imprint to obtain pattern A'. Switch to mask U2, move the platform to the exposure position of pattern B, and imprint to obtain pattern area U2, corresponding to pattern B. Switch to mask U3, move the platform to the exposure position of pattern C, and imprint.

[0157] After several imprinting and splicing processes, the substrate undergoes subsequent development, etching, and other processes to obtain multiple complete S-patterns on the substrate.

[0158] As described above, this invention is applied to splicing photolithography or nanoimprint fabrication processes. Repeating pattern units in the layout diagram are transferred to the substrate through multiple pattern transfer steps to define a repeating pattern. The area of ​​the fabricated metasurface lens is not limited by the size of a single exposure or imprinting area. Identical patterns differing by any angle can be exposed or imprinted using the same substrate at a certain angle by rotating the stage.

[0159] In the method of splicing to fabricate large metasurface lenses, the fabrication processes of Examples 5 and 6 are simple, and the low-cost preparation of large-area metasurface lens structures is achieved. This provides a new low-cost large-scale preparation technology for large-area metasurface lens structures. At the same time, the complete large-area metasurface lens pattern after splicing can be used to make a master for nanoimprinting. By replicating the master, the obtained nanoimprint template can be used to fabricate metasurface lenses with this pattern design on a large scale and with high efficiency.

[0160] In the above embodiments of the present invention, by acquiring a metasurface lens image; dividing the metasurface lens image according to a preset size to obtain at least two sub-images and a mask group corresponding to each sub-image; performing image transfer on a first wafer through the at least two sub-images and the mask group corresponding to each sub-image to obtain a second wafer with the metasurface lens image; and performing lens fabrication processing on the second wafer to obtain a metasurface lens, efficiency is improved and cost is reduced while meeting optical performance requirements.

[0161] The present invention also provides a metasurface lens, which is manufactured by the metasurface lens manufacturing method described in any of the above embodiments.

[0162] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0163] Similarly, it should be understood that, in order to simplify the embodiments of the invention and to aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the embodiments of the invention are sometimes grouped together into a single embodiment, figure, or description thereof.

[0164] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments.

[0165] It should be noted that the above embodiments are illustrative of the present invention and not restrictive of the invention. The word "a" or "an" preceding an element does not exclude the existence of a plurality of such elements. The embodiments of the present invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. Unless otherwise specified, the steps in the above embodiments should not be construed as limiting the order of execution.

Claims

1. A method for fabricating a metasurface lens, characterized in that, The method includes: Acquire images of metasurface lenses; The metasurface lens image is divided according to a preset size to obtain at least two sub-images and a mask group corresponding to each sub-image. The preset size is not greater than the exposure field of view of the stepper lithography machine or not greater than the single imprint area of ​​the nanoimprint system. Image transfer is performed on the first wafer using the at least two sub-images and the mask set corresponding to each sub-image to obtain a second wafer with the metasurface lens image; The second wafer is subjected to lens fabrication to obtain a metasurface lens; The second wafer is subjected to lens fabrication processing to obtain a metasurface lens, including: The second wafer is developed, etched, cleaned, and coated to obtain the third wafer; The third wafer is divided according to the preset size to obtain at least two sub-wafers; According to the metasurface lens image, the at least two sub-wafers are spliced ​​together to obtain a spliced ​​transition lens; Measure the aberrations of the transition lens, and design a compensation lens based on the aberrations; The compensation lens is combined with the transition lens to obtain the metasurface lens.

2. The method for fabricating a metasurface lens according to claim 1, characterized in that, The metasurface lens image is divided according to a preset size to obtain at least two sub-images and a mask group corresponding to each sub-image, including: The metasurface lens image is divided according to a preset size to obtain at least two sub-images; Based on the at least two sub-images, a mask set corresponding to each sub-image is created. If there is a common image among the at least two sub-images, a mask set is created based on the common image as the mask set corresponding to the common image.

3. The method for fabricating a metasurface lens according to claim 2, characterized in that, Image transfer is performed on the first wafer using the at least two sub-images and the mask set corresponding to each sub-image to obtain a second wafer with the metasurface lens image, including: The mask group is arranged according to the metasurface lens image to obtain the arranged image mask group; The first wafer is image transferred according to the arranged image mask group to obtain the second wafer.

4. The method for fabricating a metasurface lens according to claim 3, characterized in that, After arranging the mask groups, the following is also included: If a mask group corresponds to at least two identical sub-images, then when transferring images on the first wafer, the images are transferred separately through the mask groups corresponding to the at least two identical sub-images in a preset order.

5. The method for fabricating a metasurface lens according to claim 4, characterized in that, After image transfer is performed in a preset order using the mask groups corresponding to at least two identical sub-images, the method further includes: If the masks corresponding to the at least two identical sub-images have an angular deviation during image transfer, the masks or wafers corresponding to the at least two identical sub-images are rotated until the angular deviation is eliminated, and the images are transferred in the preset order.

6. The method for fabricating a metasurface lens according to claim 1, characterized in that, The at least two sub-wafers are stitched together according to the metasurface lens image to obtain the metasurface lens, including: Based on the metasurface lens image, the optimal modulation transfer function of each pair of adjacent sub-wafers in the at least two sub-wafers is determined by active alignment. Based on the optimal modulation transfer function, the at least two sub-wafers are spliced ​​together to obtain the metasurface lens.

7. A metasurface lens, characterized in that, Fabricated using the metasurface lens fabrication method as described in any one of claims 1 to 6.

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