Imprinting method and device

Abstract

The present invention provides an imprinting method and device. First, an unstrengthened wafer is cut according to a preset shape to obtain a plurality of sub-wafers, then the sub-wafers are subjected to high-intensity strengthening treatment, and finally, an imprinting resist is applied onto the strengthened sub-wafers and imprinted to form micro-nano structures. In this way, the cutting and strengthening processes are performed in advance, eliminating the need for cutting and strengthening after the imprinted structures are formed, thus effectively preventing damage to the imprinted structures caused by subsequent cutting and strengthening. In addition, the imprinting device provided in the present invention is employed during imprinting. Before imprinting, a soft film tension adjusting assembly is located at a first height, so that the tension of a flexible soft film satisfies the requirement for tensioning the flexible soft film; and during imprinting, the soft film tension adjusting assembly is located at a second height, so that the tension of the flexible soft film is kept at zero. The technical solution provided in the present application can improve an imprinting effect.

Description

An imprinting method and apparatus Technical Field

[0001] This invention relates to the field of nanoimprint technology, and more particularly to an imprinting method and apparatus. Background Technology

[0002] Nanoimprint lithography is one of the mainstream technologies for fabricating surface relief structures in augmented reality diffractive waveguides. It uses an imprinting transfer method to mass-produce and low-cost replicate the surface relief structure from a master template onto a glass wafer, thereby creating a diffractive waveguide. However, existing nanoimprint lithography processes involve applying pressure and rolling pressure. During this process, the tension of the flexible film affects its deformation, thus impacting the quality of the imprinted microstructure. Therefore, controlling the tension of the flexible film is crucial, but because the tension of the flexible film is difficult to control, the imprinting results are often unsatisfactory. Summary of the Invention

[0003] This invention provides an imprinting method and apparatus. First, an untempered wafer is cut according to a preset shape to obtain multiple sub-wafers. Then, the sub-wafers undergo a high-strength tempering treatment. Finally, imprinting adhesive is applied to the tempered sub-wafers, and a micro / nano structure is formed by imprinting. In this way, the cutting and tempering processes are performed beforehand, eliminating the need for further cutting and tempering after the imprinted structure is formed. This effectively prevents damage to the imprinted structure caused by cutting and tempering, improving the performance and quality of the diffractive waveguide. During the imprinting process, using this imprinting apparatus, the height of the flexible film tension adjustment component is adjusted to ensure that the flexible film is in a taut state before imprinting, facilitating the transmission and shape maintenance of the flexible film. During the imprinting process, the tension of the flexible film is kept at zero to prevent deformation caused by tension. This improves the structural transfer effect of nanoimprinting, resulting in more accurate and consistent microstructure imprinting. Attached Figure Description

[0004] Figures 1 to 6 are schematic diagrams of a nanoimprint device provided in an embodiment of this application;

[0005] Figures 7 to 13 are schematic diagrams of the structure and process of an imprinting method provided by the present invention. Detailed Implementation

[0006] This application provides a nanoimprinting apparatus for microstructure transfer of a flexible film. The nanoimprinting apparatus includes a film fixing component, a film tension adjusting component, an impression roller, and an impression platform. The flexible film has a first end and a second end. The first end is connected to the film fixing component, and the second end is connected to the film tension adjusting component. The height of the film tension adjusting component is adjustable so that the tension of the flexible film changes with the movement of the film tension adjusting component. The flexible film is located between the impression roller and the impression platform, and the impression roller can move back and forth in the extension direction of the flexible film. Before imprinting, the film tension adjusting component is located at a first height so that the tension of the flexible film is sufficient to tighten the flexible film. During the imprinting process, the film tension adjusting component is located at a second height so that the tension of the flexible film remains zero.

[0007] Specifically, the nanoimprint apparatus provided in this application is used for microstructure transfer on flexible films. It should be noted that the aforementioned microstructure transfer on flexible films includes two scenarios: transferring microstructures from the flexible film to other components, and transferring microstructures from other components to the flexible film. Specifically, the microstructure can be a surface-embossed grating. The nanoimprint method provided in this application includes two stages, with different states of the flexible film in each stage. In the pre-imprint preparation stage, the flexible film is in a stretched state, i.e., flattened. In the imprint stage, the flexible film is in a relaxed state, without any force, and the tension is zero.

[0008] Referring to Figures 1-3, Figure 1 is a schematic diagram of the nanoimprint apparatus during the imprinting preparation stage, and Figures 2-3 are schematic diagrams of the nanoimprint apparatus during the imprinting stage. The nanoimprint apparatus 100 includes a flexible film fixing component 120, a flexible film tension adjusting component 130, an imprinting roller 140, and an imprinting platform 150. A wafer 160 is placed on the imprinting platform 150. The microstructure on the wafer 160 is transferred to the flexible film 110 by applying pressure to the flexible film 110 through the imprinting roller 140, or the microstructure on the flexible film 110 is transferred to the wafer 160.

[0009] The flexible film 110 has a first end and a second end. The first end is connected to the film fixing assembly 120, and the second end is connected to the film tension adjusting assembly 130. The position of the film fixing assembly 120 is fixed, while the height of the film tension adjusting assembly 130 is adjustable. When both the film fixing assembly 120 and the film tension adjusting assembly 130 are in fixed contact with the flexible film, the tension of the flexible film changes with the movement of the film tension adjusting assembly. The flexible film 110 is located between the impression roller 140 and the impression platform 150, and the impression roller 140 can move back and forth in the extension direction of the flexible film 110 to achieve impressioning and demolding.

[0010] Specifically, during the imprinting preparation stage, the flexible film tension adjustment component is positioned at a first height to ensure the flexible film is taut. This ensures the flexible film is taut before imprinting, facilitating its transmission and maintenance of its shape and structure. During the imprinting process, the flexible film tension adjustment component is positioned at a second height to maintain zero tension on the flexible film. This controls the flexible film from being subjected to tension during imprinting, thereby ensuring consistent stretching of the microstructures on the film and uniform filling of the imprinted structure.

[0011] It should be noted that the aforementioned first height and second height are different heights and are not specific height values. Any height that can satisfy the tension of the flexible membrane to achieve the desired tightness can be considered the first height, and any height that can make the tension of the flexible membrane zero can be considered the second height.

[0012] In practice, the nanoimprint apparatus also includes a guide wheel, after which the flexible film passes sequentially over the top of the rolling wheel of the film fixing assembly and below the imprint roller, and is connected to the rolling wheel of the film tension adjusting assembly, and separates from the protective film of the flexible film above the rolling wheel of the film fixing assembly.

[0013] In practice, the rollers of the PVC membrane fixing assembly and the rollers of the PVC membrane tension adjusting assembly are used to select the flexible PVC membrane by rolling. After selection, the first end of the flexible PVC membrane is fixed on the roller of the PVC membrane fixing assembly, and the second end of the flexible PVC membrane is fixed on the roller of the PVC membrane fixing assembly.

[0014] In practice, the nanoimprinting device also includes a first auxiliary wheel and a second auxiliary wheel, the first auxiliary wheel being used to assist in the release of the flexible film and the second auxiliary wheel being used to assist in the recycling of the flexible film.

[0015] Specifically, referring to Figures 4-5, the nanoimprint apparatus 100 includes: a flexible film fixing assembly 120, a flexible film tension adjusting assembly 130, an impression roller 140, an impression platform 150, and a guide wheel 170. Both the flexible film fixing assembly 120 and the flexible film tension adjusting assembly 130 include rolling wheels. The flexible film 110 passes over the top of the rolling wheel of the flexible film fixing assembly 120 and the bottom of the impression roller 140 after passing over the guide wheel 170, and then connects to the rolling wheel of the flexible film tension adjusting assembly 130. It separates from the protective film of the flexible film 110 above the rolling wheel of the flexible film fixing assembly 120. During the imprint preparation stage, the flexible film 110 makes active contact with both the flexible film fixing assembly 120 and the flexible film tension adjusting assembly 130. Thus, when the rolling wheels of the flexible film fixing assembly and the flexible film tension adjusting assembly roll, they can drive the flexible film to be transported, thereby achieving the rolling selection of the flexible film. After selection, the first end of the flexible film is fixed to the rolling wheel of the film fixing assembly, and the second end of the flexible film is fixed to the rolling wheel of the film fixing assembly. That is, the flexible film 110 switches from active contact with the film fixing assembly 120 and the film tension adjusting assembly 130 to fixed contact. Further, referring to Figures 4-5, the nanoimprinting device 100 also includes a first auxiliary wheel 180 and a second auxiliary wheel 190. The first auxiliary wheel 180 is used to assist in material collection, and the second auxiliary wheel 190 is used to assist in material feeding.

[0016] It can be assumed that during the non-imprinting process, the flexible film tension adjustment component 130 is always located at the first height to ensure that the tension of the flexible film is sufficient for tautness throughout the entire non-imprinting process. During the imprinting process, the flexible film tension adjustment component 130 is located at the second height to keep the tension of the flexible film at zero throughout the entire imprinting process.

[0017] The flexible membrane tension adjustment assembly is equipped with a sensor and a drive unit. The sensor is used to detect the alignment status of the flexible membrane, and the drive unit is used to move the flexible membrane tension adjustment assembly to adjust the alignment status of the flexible membrane when the alignment status of the flexible membrane does not meet the alignment conditions.

[0018] When using a flexible film for imprinting, it should be flat and aligned at both ends. If the first and second ends of the flexible film are misaligned and twisted, the imprinting effect will be severely affected. Specifically, referring to Figure 6, the film tension adjustment assembly 130 is equipped with a sensor 210 and a drive unit 220. The sensor 210 is used to detect the alignment state of the flexible film 110, and the drive unit 220 is used to move the roller 230 of the film tension adjustment assembly 130 left and right to adjust the alignment state of the flexible film 110 when the alignment state of the flexible film 110 does not meet the alignment conditions. For example, the sensor can be an image sensor, which determines whether the alignment state of the flexible film meets the alignment conditions by acquiring an image of the second end of the flexible film. If the alignment state of the flexible film meets the alignment conditions, the imprinting stage can be entered; if the alignment state of the flexible film does not meet the alignment conditions, the alignment state of the flexible film can be adjusted before entering the imprinting stage.

[0019] In the nanoimprint apparatus provided in this application, instead of using complex structures and procedures to monitor the tension of the flexible film in real time and maintain constant tension to ensure consistent deformation of the flexible film as a whole, the height of the film tension adjustment component is adjusted so that the flexible film is in a taut state before imprinting, which facilitates the transmission of the flexible film and the maintenance of its shape and structure. During the imprinting process, the tension of the flexible film is kept at zero to avoid deformation of the flexible film due to tension. This can improve the structural transfer effect of nanoimprinting, making the microstructure transfer more accurate and more consistent.

[0020] It should be noted that during the imprinting preparation stage before imprinting, the flexible film is in a taut state and preferably does not deform, which can better ensure the consistency of microstructure filling. In another embodiment, during the imprinting preparation stage before imprinting, the flexible film is in a taut state and deformation is allowed, but the overall stretch of the flexible film must remain consistent.

[0021] This application also provides two nanoimprinting methods based on the above-mentioned nanoimprinting device, specifically:

[0022] In one embodiment, a nanoimprinting method employing the above-described nanoimprinting apparatus includes:

[0023] S110, after forming an imprinting adhesive layer on the side of the wafer with microstructure, is placed on an imprinting platform;

[0024] S120, adjust the membrane tension adjustment component to the first height so that the tension of the flexible membrane meets the requirements for flexible membrane tensioning;

[0025] S130, the flexible film tension adjustment component is adjusted to the second height, and the imprint roller is controlled to apply pressure to the flexible film, so that the imprint adhesive layer on the flexible film and the wafer on the imprint platform come into contact; and the imprint roller is continued to be controlled to roll in a direction away from the flexible film fixing component to apply pressure to the flexible film, so that the microstructure on the wafer is transferred to the imprint adhesive layer and then to the flexible film; wherein, during the imprinting process, the tension of the flexible film is kept at zero.

[0026] In practice, the above-mentioned nanoimprinting method further includes, before step S230, controlling the rolling wheel of the soft film fixing component and the rolling wheel of the soft film tension adjusting component to roll, so as to select a flexible soft film, and after the selection is completed, fixing the first end of the flexible soft film on the rolling wheel of the soft film fixing component, and fixing the second end of the flexible soft film on the rolling wheel of the soft film fixing component.

[0027] The above nanoimprinting method further includes: before step S120, coating an adhesive material on the side of the flexible film facing the imprinting platform; after step S130, leaving an imprinting adhesive layer with a microstructure on the flexible film after removing the flexible film.

[0028] The above-mentioned nanoimprinting method further includes: before step S130, the method further includes: before imprinting, detecting the alignment state of the flexible film by a sensor; if the alignment state of the flexible film does not meet the alignment conditions, driving the film tension adjustment component to move by a driving component to adjust the alignment state of the flexible film.

[0029] The nanoimprinting process in this embodiment is the process of transferring the microstructure on the master plate onto the flexible film. Specifically, in the example of preparing a diffractive waveguide, referring to Figures 4-5, in some scenarios, the flexible film has a protective film. On the one hand, after preparing the master plate with the surface relief grating structure, an imprinting adhesive layer is formed on the side of the master plate with the surface relief grating structure and then placed on the imprinting platform 150. On the other hand, in the nanoimprinting device, after the flexible film passes around the lower right of the second auxiliary wheel 190, it passes sequentially around the upper left of the guide wheel 170, above the rolling wheel of the film fixing component 120, below the imprinting roller 140, above the rolling wheel of the film tension adjusting component 130, and the lower left of the first auxiliary wheel 180 before being retrieved. This portion of the flexible film between the film fixing component 120 and the film tension adjusting component 130 is the target area for imprinting. During the imprinting preparation stage, the flexible film tension adjustment component 130 is at the first height, and the tension of the flexible film 110 is not zero, placing it in a tensile state. The flexible film 110 is in movable contact with both the flexible film fixing component 120 and the flexible film tension adjustment component 130. This allows the rolling wheels of both the flexible film fixing component 120 and the flexible film tension adjustment component 130 to drive the flexible film 110 during rolling, thus enabling the selection of the flexible film 110. After selection, the first end of the flexible film 110 is fixed to the rolling wheel of the flexible film fixing component 130, and the second end of the flexible film 110 is also fixed to the rolling wheel of the flexible film fixing component 130. In other words, the contact between the flexible film 110 and the flexible film fixing component 120 and the flexible film tension adjustment component 130 changes from movable contact to fixed contact. The height of the flexible film tension adjustment component 130 then decreases to the second height, causing the tension of the flexible film 110 to become zero, placing it in a relaxed state. Further, the impression roller 140 is controlled to apply pressure to the flexible film 110, causing the flexible film 110 to contact the impression adhesive layer of the master plate on the impression platform; and the impression roller 140 continues to be controlled to roll away from the film fixing assembly 120 to apply pressure to the flexible film 110, so that the surface relief grating structure on the master plate is transferred to the impression adhesive layer and then to the flexible film 110; wherein, during the impression process, the tension of the flexible film 110 remains zero. Further, the transferred surface relief grating structure is shaped by UV light from the UV exposure device. After that, the impression roller 140 rolls toward the film fixing assembly 120, causing the impression adhesive layer with the surface relief grating structure to separate from the surface relief grating structure of the master plate, so that the impression adhesive layer with the surface relief grating structure remains on the flexible film, resulting in a flexible film with a surface relief grating structure for imprinting diffractive waveguide products.

[0030] In one embodiment, a nanoimprinting method employing the above-described nanoimprinting apparatus includes:

[0031] S210, after forming an imprinting adhesive layer on the wafer, is placed on an imprinting platform;

[0032] S220, adjust the membrane tension adjustment component to the first height so that the tension of the flexible membrane meets the requirements for flexible membrane tensioning;

[0033] S230, the flexible film tension adjustment component is adjusted to the second height, and the imprint roller is controlled to apply pressure to the flexible film, so that the flexible film and the imprint adhesive on the wafer come into contact; and the imprint roller is continued to be controlled to roll in a direction away from the flexible film fixing component to apply pressure to the flexible film, so that the microstructure on the flexible film is transferred to the imprint adhesive; wherein, during the imprinting process, the tension of the flexible film is kept at zero.

[0034] The above-mentioned nanoimprinting method further includes: before step S230, the method further includes: before imprinting, detecting the alignment state of the flexible film by a sensor; if the alignment state of the flexible film does not meet the alignment conditions, driving the film tension adjustment component to move by a driving component to adjust the alignment state of the flexible film.

[0035] The nanoimprinting process in this embodiment is the process of transferring the microstructure on a flexible film onto the product. Specifically, in the example of fabricating a diffractive waveguide, referring to Figures 4-5, in some scenarios, the flexible film has a protective film. On the one hand, after forming an imprinting adhesive layer on the surface of the waveguide substrate, it is placed on the imprinting platform 150. On the other hand, in the nanoimprinting device, after the flexible film passes around the lower right of the second auxiliary wheel 190, it sequentially passes around the upper left of the guide wheel 170, above the rolling wheel of the film fixing assembly 120, below the imprinting roller 140, above the rolling wheel of the film tension adjusting assembly 130, and the lower left of the first auxiliary wheel 180 before being retrieved. This portion of the flexible film between the film fixing assembly 120 and the film tension adjusting assembly 130 is the target area for imprinting. During the imprinting preparation stage, the flexible film tension adjustment component 130 is at the first height, and the tension of the flexible film 110 is not zero, placing it in a tensile state. The flexible film 110 is in movable contact with both the flexible film fixing component 120 and the flexible film tension adjustment component 130. This allows the rolling wheels of both the flexible film fixing component 120 and the flexible film tension adjustment component 130 to drive the flexible film 110 during rolling, thus enabling the selection of the flexible film 110. After selection, the first end of the flexible film 110 is fixed to the rolling wheel of the flexible film fixing component 130, and the second end of the flexible film 110 is also fixed to the rolling wheel of the flexible film fixing component 130. In other words, the contact between the flexible film 110 and the flexible film fixing component 120 and the flexible film tension adjustment component 130 changes from movable contact to fixed contact. The height of the flexible film tension adjustment component 130 then decreases to the second height, causing the tension of the flexible film 110 to become zero, placing it in a relaxed state. Further, the impression roller 140 is controlled to apply pressure to the flexible film 110, causing the surface relief grating structure of the flexible film 110 to contact the imprinting adhesive layer on the waveguide substrate on the impression platform; and the impression roller 140 is further controlled to roll away from the film fixing assembly 120 to apply pressure to the flexible film 110, so that the surface relief grating structure on the flexible film is transferred to the imprinting adhesive layer and then to the waveguide substrate; wherein, during the imprinting process, the tension of the flexible film 110 remains zero. Further, the transferred surface relief grating structure is shaped by UV light from the UV exposure device. After that, the impression roller 140 rolls toward the film fixing assembly 120, causing the imprinting adhesive layer with the surface relief grating structure to separate from the surface relief grating structure of the flexible film, so that the imprinting adhesive layer with the surface relief grating structure remains on the waveguide substrate, resulting in a diffractive waveguide product with a surface relief grating structure.

[0036] Before entering the imprinting stage, the alignment status of the flexible film must be detected by sensors. If the alignment status of the flexible film 110 does not meet the alignment conditions, the drive unit is activated to move the rolling wheel of the film tension adjustment component left and right to adjust the alignment status of the flexible film. Once the alignment status of the flexible film meets the alignment conditions, the imprinting stage can proceed.

[0037] Furthermore, based on the above embodiments, the present invention also provides an imprint fabrication method for a diffractive optical waveguide, comprising the following steps:

[0038] Provide a wafer that has not undergone high-strength surface tempering treatment;

[0039] The wafer is cut according to the preset shape of the diffractive waveguide to form a number of sub-wafers with several shapes.

[0040] A number of sub-wafers are subjected to high-strength surface tempering treatment to obtain a number of tempered sub-wafers;

[0041] Imprinting adhesive is applied to the surface of several of the tempered sub-wafers;

[0042] The embossing adhesive is embossed using an embossing master to form an embossed micro / nano structure.

[0043] Based on the method provided by this invention, the cutting and tempering processes for fabricating diffractive waveguides in the prior art are adjusted. Instead of forming the imprinted structure first and then cutting the wafer, the wafer is cut before forming the imprinted structure, as in this invention. The cutting process and the high-strength tempering process are moved forward. This process means that after forming the imprinted structure, the cutting and tempering processes are no longer needed. The required imprinted micro / nano structure is formed after cutting and tempering.

[0044] First, the pre-cutting process avoids structural and mechanical damage to the imprinted structure. Second, it prevents dust particles generated during the cutting process from adhering to the gaps and surfaces of the imprinted micro / nano structure and becoming difficult to remove completely. Third, the burrs generated during the cutting process can be removed by other processes before imprinting, ensuring that the outer edge of the diffractive waveguide structure formed by imprinting is free of burrs, preventing light scattering and leakage at the waveguide edge, and further improving the display performance and appearance of the waveguide.

[0045] This application places the high-strength tempering process in the front, which can significantly improve the mechanical strength of several sub-wafers in the subsequent imprinting process. This is different from the prior art that uses untempered wafers or wafers with low-strength tempering processes for imprinting and cutting, and is conducive to improving the imprinting quality.

[0046] In the above method, the wafer can be made of materials such as silicon, glass, resin, lithium niobate, magnesium fluoride, zinc sulfide, gallium arsenide, silicon dioxide, silicon nitride, silicon carbide, gallium nitride, and indium phosphide.

[0047] For glass wafers and resin wafers, which are commonly used in this field as wafer materials for diffractive optical waveguides, the method provided by this invention is applicable not only to glass wafers but also to resin wafers. To further explain, since resin wafers have relatively poor mechanical strength, the method of this invention can first cut wafers with sizes of 6 inches, 8 inches, or even larger into several sub-wafers, cutting larger wafers into smaller sub-wafers, and then performing surface tempering treatment on several sub-wafers, which can improve the mechanical strength of each resin sub-wafer in subsequent processes. Moreover, it is known that mature imprinting processes for resin wafers are more suitable for smaller resin wafers, such as 3-inch wafers. Therefore, dividing large-sized wafers into small-sized sub-wafers can be adapted to existing mature imprinting processes for resin wafers, avoiding the complex imprinting processes required for large-sized wafers. Simultaneously, cutting into several sub-wafers first facilitates accurate measurement of the total thickness variation and modulation transfer function of different waveguides, enabling measurement and inspection at the raw material stage, improving the accuracy of wafer performance testing, and avoiding the inaccuracies of large-sized testing. Therefore, the method of the present invention significantly improves the applicability of existing imprinting processes, especially for imprinting processes of resin wafers such as 6-inch and 8-inch wafers.

[0048] To further explain the above steps in detail, firstly, a wafer without high-strength surface tempering is provided. Here, "without high-strength surface tempering" means that the wafer has not undergone the high-strength surface tempering treatment used in the prior art for dicing diffractive waveguide products. It does not mean that the wafer has not undergone other similar pre-treatment methods to enhance its mechanical strength and improve the mechanical strength during dicing. More specifically, high-strength surface tempering typically refers to a wafer with a strength value of 50-1000 MPa after high-strength tempering treatment; it may include low-strength surface tempering treatment, such as a few megapascals or tens of megapascals. That is, in this invention, providing a wafer without high-strength surface tempering treatment means that the wafer can be processed by a low-strength surface tempering process, or a wafer that has not been processed by any surface tempering process. As long as it does not depart from the spirit of this invention, it is within the scope of protection of this application.

[0049] Of course, for glass wafers, no surface treatment is required before proceeding to the next step. For resin wafers, the surface pretreatment can be performed to enhance mechanical strength during cutting, depending on the cutting process. If the cutting process can cut resin wafers without any surface pretreatment, it can be cut directly. If the cutting process cannot cut resin wafers without any surface pretreatment, the surface pretreatment is required to enhance its mechanical strength during cutting to meet the requirements of the cutting process. However, the pretreatment here refers to low-strength tempering, not high-strength tempering.

[0050] Furthermore, according to the preset shape of the diffractive waveguide, the wafer is cut to form several sub-wafers including several shapes; as shown in Figure 7, a wafer 10 is provided, and according to the different shapes of the preset diffractive waveguide, the wafer is reasonably arranged in the wafer, and the wafer 10 is cut according to the preset outline of the diffractive waveguide to form several sub-wafers 1100 including several shapes; Figure 7 shows that the several sub-wafers 1100 can have the same structural shape or different structural shapes.

[0051] In this step, since the surface of the provided wafer 10 does not have any imprinted structures, especially imprinted grating structures, the mechanical vibrations generated during dicing will not affect the imprinted structures. Simultaneously, the dust generated during dicing is more easily removed. The diced sub-wafer can be cleaned using conventional cleaning processes, preventing dust from being carried into subsequent imprinting processes and ensuring thorough dust removal before imprinting. Of course, any burrs generated during dicing can also be edge-treated in this step to improve the imprinting quality of the sub-wafer. This approach improves the optical performance and appearance yield of the formed diffractive waveguide product.

[0052] Furthermore, a high-strength surface tempering treatment is performed on several sub-wafers to obtain several tempered sub-wafers. In this step, as shown in FIG8, a compressive stress layer is formed on the surface of several sub-wafers by physical or chemical methods, thereby improving the mechanical strength and scratch resistance of the sub-wafers. By controlling the parameters of each step in the physical or chemical methods, the high-strength surface tempering treatment requirements of this application are achieved.

[0053] Specifically, for glass wafers, one method involves ion exchange, in which several sub-wafers are immersed in a high-temperature nitrate melt, causing sodium ions on the wafer surface to exchange with potassium ions in the melt. Since potassium ions are larger than sodium ions, a compressive stress layer forms on the wafer surface upon cooling, thereby improving the wafer's strength and scratch resistance.

[0054] In this process, the temperature, time, and composition of the molten salt for ion exchange are precisely controlled. Generally, the temperature range is 400℃ to 500℃, and the time is adjusted according to factors such as wafer thickness and composition.

[0055] In detail, for glass wafers, another method involves physical tempering. Several sub-wafers are heated to near their wafer transition temperature and then rapidly cooled using a gaseous or liquid medium. The rapid contraction of the wafer surface creates a compressive stress layer, thereby enhancing the mechanical strength of the glass.

[0056] Furthermore, for resin wafers, one approach is to coat the surface with a hard material, such as silicon dioxide or aluminum oxide, to form a protective layer, thereby improving surface hardness and wear resistance. This coating can be applied using methods such as chemical vapor deposition (CVD) or physical vapor deposition (PVD). Alternatively, highly reactive groups or molecules can be introduced onto the resin surface through chemical reactions, altering the surface's chemical structure and thus improving hardness, scratch resistance, and chemical resistance. Another approach is to bombard and modify the resin wafer surface using plasma. High-energy particles in the plasma can break the chemical bonds on the resin surface, forming free radicals, which then trigger cross-linking and polymerization reactions, making the surface denser and harder.

[0057] Of course, the above only illustrates common surface tempering methods, and may include other possible surface tempering methods.

[0058] In this step, the sub-wafers are subjected to high-strength surface tempering treatment, which can significantly improve the mechanical strength, hardness, scratch resistance and chemical resistance of each sub-wafer surface. Compared with the traditional method, the present invention tempers each sub-wafer surface in advance, which can improve the wear resistance of the wafer surface in subsequent imprinting and etching processes, prevent the wafer surface from being scratched by subsequent processes, and improve the mechanical strength of the wafer surface in each process step.

[0059] Furthermore, after the sub-wafer undergoes high-strength surface tempering, defects such as cracks may appear on the surface of the sub-wafer. This also includes surface defect treatment of the surface or edges of the sub-wafer after high-strength surface tempering, such as polishing and grinding, to improve the tempering quality of the surface and edges of the tempered sub-wafer.

[0060] Before setting the imprinting adhesive, a step of surface activation of several tempered sub-wafers is also included to enhance the adhesion between the imprinting adhesive and the surface of the tempered sub-wafers, ensure that the imprinting adhesive does not fall off or generate bubbles during the imprinting process, and improve the integrity and stability of the imprinted micro / nano structure.

[0061] Furthermore, based on the above steps, an imprinting adhesive is coated onto the surfaces of several tempered sub-wafers. In one embodiment, a predetermined volume of imprinting adhesive can be printed on the surface of each tempered sub-wafer using inkjet printing on the area of ​​the desired structure, as shown in Figure 9. Based on the imprinting process or imprint etching process, the required grating structure is formed, and a predetermined volume of imprinting adhesive is printed on different areas of the surfaces of several tempered sub-wafers, such as the coupling-in region, transition region, and coupling-out region of a diffractive waveguide. In one embodiment, the imprinting adhesive is a grating material, which is a common grating material in the art.

[0062] As shown in Figure 10, the process involves first placing several tempered sub-wafers 1100 on a substrate 20 and fixing them in place. Then, an imprinting adhesive layer is coated onto the surface of the tempered sub-wafers 1100 using inkjet printing or a spin coating method. Other methods for applying the imprinting adhesive layer are also included. This method enables mass imprinting. After subsequent processing, the wafers are removed from the substrate 20 to obtain the diffractive waveguide product.

[0063] Referring again to Figure 11, using a cross-section of a tempered sub-wafer 1100 as an illustration, imprinting adhesive is placed at different locations. An imprinting master 30 is used to imprint the imprinting adhesive at these different locations, forming an imprinted micro / nano structure 1001. In one embodiment, since the imprinting adhesive is a grating material, the imprinted micro / nano structure 1001 is an imprinted diffraction grating structure, thus obtaining a diffraction waveguide product.

[0064] A diffraction grating structure can be formed by etching, as shown in Figure 12. Imprinting adhesive is applied to the surface of the tempered sub-wafer 1100, and the imprinting adhesive is imprinted using a conventional imprinting process to form an imprinted micro / nano structure 1001. Specifically, the nanoimprinting apparatus provided in the aforementioned embodiment is used to imprint the formed imprinted micro / nano structure 1001. The patterned structure of the imprinted micro / nano structure 1001 is transferred to the tempered sub-wafer 1100 through an etching process, and a diffraction grating structure is formed on the tempered sub-wafer 1100. In this embodiment, the desired optical structure, such as a diffraction grating structure, is formed through imprinting and etching processes. In this embodiment, the tempered sub-wafer 1100 can be selected from materials such as lithium niobate, magnesium fluoride, zinc sulfide, gallium arsenide, silicon dioxide, silicon nitride, silicon carbide, gallium nitride, and indium phosphide.

[0065] During the imprinting process, the imprinting device used is the one provided in the embodiments shown in Figures 1 to 6, in order to realize the above imprinting process.

[0066] Of course, Figures 11 and 12 are merely simplified process flow diagrams of the imprinting and etching processes. They do not represent the specific structure of the imprinting master, the diffraction grating, its location, or the specific imprinting and etching steps. They illustrate that a diffraction grating can be formed through either imprinting or etching. Furthermore, as those skilled in the art will understand, the depth of the grating structure can continuously and gradually change at different grating structure locations. The grating structures in the figures are for illustrative purposes only.

[0067] Furthermore, the present invention provides a diffractive optical waveguide, which is prepared based on the preparation method described in any of the foregoing embodiments.

[0068] Meanwhile, the present invention provides an augmented reality display device, including the diffractive waveguide as described above.

[0069] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for imprinting a diffractive optical waveguide, characterized in that, Includes the following steps: Provide a wafer that has not undergone high-strength surface tempering treatment; The wafer is cut according to the preset shape of the diffractive waveguide to form a number of sub-wafers with several shapes. A number of sub-wafers are subjected to high-strength surface tempering treatment to obtain a number of tempered sub-wafers; Imprinting adhesive is applied to the surface of several of the tempered sub-wafers; The embossing adhesive is embossed using an embossing master to form an embossed micro / nano structure.

2. The imprint fabrication method for a diffractive optical waveguide according to claim 1, characterized in that, It also includes transferring the pattern of the imprinted micro-nano structure to the surface of the tempered sub-wafer through an etching process based on the imprinted micro-nano structure, and etching a grating structure matching the imprinted micro-nano structure on the surface of the tempered sub-wafer.

3. The imprint fabrication method for a diffractive optical waveguide according to claim 1 or 2, characterized in that, The surface tempering treatment method includes one or more of chemical tempering, physical tempering, or surface coating; before applying the imprinting adhesive, it also includes surface defect treatment of the surfaces and edges of several tempered sub-wafers.

4. The imprint fabrication method for a diffractive optical waveguide according to claim 1 or 2, characterized in that, The printing adhesive is printed using a printing master, and more specifically, it also includes a nanoprinting device for microstructure transfer of the flexible film. The nanoimprint apparatus includes: The invention comprises a flexible film fixing assembly, a flexible film tension adjusting assembly, an impression roller, and an impression platform; wherein the flexible film has a first end and a second end, the first end being connected to the flexible film fixing assembly, and the second end being connected to the flexible film tension adjusting assembly; the height of the flexible film tension adjusting assembly is adjustable so that the tension of the flexible film changes as the flexible film tension adjusting assembly moves; the flexible film is located between the impression roller and the impression platform, and the impression roller is capable of moving back and forth in the extension direction of the flexible film; before impressioning, the flexible film tension adjusting assembly is located at a first height to ensure that the tension of the flexible film is sufficient for the flexible film to be taut; during impressioning, the flexible film tension adjusting assembly is located at a second height to keep the tension of the flexible film at zero.

5. The imprint fabrication method for a diffractive optical waveguide according to claim 4, characterized in that, A predetermined volume of imprinting adhesive is printed on the surface of several tempered sub-wafers using inkjet printing, with each grating structure region having a different volume.

6. The imprint fabrication method for a diffractive optical waveguide according to claim 3, characterized in that, The wafer is a glass wafer or a resin wafer; the surface of the resin wafer is also pretreated before dicing.

7. The imprint fabrication method for a diffractive optical waveguide according to claim 4, characterized in that, The nanoimprinting device also includes a guide wheel. The flexible film passes behind the guide wheel, successively around the top of the rolling wheel of the film fixing assembly and the bottom of the imprinting roller, and then connects to the rolling wheel of the film tension adjusting assembly. It separates from the protective film of the flexible film above the rolling wheel of the film fixing assembly.

8. The imprint fabrication method for a diffractive optical waveguide according to claim 4, characterized in that, The rolling wheel of the soft film fixing assembly and the rolling wheel of the soft film tension adjusting assembly are used to select the flexible soft film by rolling. After selection, the first end of the flexible soft film is fixed on the rolling wheel of the soft film fixing assembly, and the second end of the flexible soft film is fixed on the rolling wheel of the soft film fixing assembly.

9. The imprint fabrication method for a diffractive optical waveguide according to claim 4, characterized in that, The flexible membrane tension adjustment assembly is equipped with a sensor and a driving component. The sensor is used to detect the alignment state of the flexible membrane, and the driving component is used to move the flexible membrane tension adjustment assembly to adjust the alignment state of the flexible membrane when the alignment state of the flexible membrane does not meet the alignment conditions.

10. The imprint fabrication method for a diffractive optical waveguide according to claim 4, characterized in that, The nanoimprinting device further includes a first auxiliary wheel and a second auxiliary wheel. The first auxiliary wheel is used to assist in the release of the flexible film, and the second auxiliary wheel is used to assist in the recycling of the flexible film.

11. A nanoimprinting device, characterized in that, The nanoimprinting device is used for microstructure transfer of flexible films. The invention comprises a flexible film fixing assembly, a flexible film tension adjusting assembly, an impression roller, and an impression platform; wherein the flexible film has a first end and a second end, the first end being connected to the flexible film fixing assembly, and the second end being connected to the flexible film tension adjusting assembly; the height of the flexible film tension adjusting assembly is adjustable so that the tension of the flexible film changes as the flexible film tension adjusting assembly moves; the flexible film is located between the impression roller and the impression platform, and the impression roller is capable of moving back and forth in the extension direction of the flexible film; before impressioning, the flexible film tension adjusting assembly is located at a first height to ensure that the tension of the flexible film is sufficient for the flexible film to be taut; during impressioning, the flexible film tension adjusting assembly is located at a second height to keep the tension of the flexible film at zero.

12. The nanoimprint apparatus according to claim 11, characterized in that, The nanoimprinting device also includes a guide wheel. The flexible film passes behind the guide wheel, successively around the top of the rolling wheel of the film fixing assembly and the bottom of the imprinting roller, and then connects to the rolling wheel of the film tension adjusting assembly. It separates from the protective film of the flexible film above the rolling wheel of the film fixing assembly.

13. The nanoimprint apparatus according to claim 12, characterized in that, The rolling wheel of the soft film fixing assembly and the rolling wheel of the soft film tension adjusting assembly are used to select the flexible soft film by rolling. After selection, the first end of the flexible soft film is fixed on the rolling wheel of the soft film fixing assembly, and the second end of the flexible soft film is fixed on the rolling wheel of the soft film fixing assembly.

14. The nanoimprint apparatus according to claim 13, characterized in that, The flexible membrane tension adjustment assembly is equipped with a sensor and a driving component. The sensor is used to detect the alignment state of the flexible membrane, and the driving component is used to move the flexible membrane tension adjustment assembly to adjust the alignment state of the flexible membrane when the alignment state of the flexible membrane does not meet the alignment conditions.

15. The nanoimprint apparatus according to claim 12, characterized in that, The nanoimprinting device further includes a first auxiliary wheel and a second auxiliary wheel. The first auxiliary wheel is used to assist in the release of the flexible film, and the second auxiliary wheel is used to assist in the recycling of the flexible film.

16. The nanoimprint apparatus according to claim 11 or 13, characterized in that, The nanoimprint device, when in use, includes: After forming an imprinting adhesive layer on the side of the wafer with microstructures, it is placed on the imprinting platform; The flexible membrane tension adjustment component is adjusted to a first height so that the tension of the flexible membrane meets the requirements for tautness. The flexible film tension adjustment component is adjusted to a second height, and the imprint roller is controlled to apply pressure to the flexible film, so that the imprint adhesive layer on the flexible film and the microstructure of the wafer on the imprint platform come into contact; and the imprint roller is continued to be controlled to roll away from the flexible film fixing component to apply pressure to the flexible film, so that the microstructure on the wafer is transferred to the imprint adhesive layer and then to the flexible film; wherein, during the imprinting process, the tension of the flexible film remains at zero.

17. The nanoimprint apparatus according to claim 16, characterized in that, Also includes: The rolling wheels of the soft film fixing assembly and the soft film tension adjusting assembly are controlled to roll to select the flexible soft film. After selection, the first end of the flexible soft film is fixed on the rolling wheel of the soft film fixing assembly, and the second end of the flexible soft film is fixed on the rolling wheel of the soft film fixing assembly.

18. The nanoimprint apparatus according to claim 17, characterized in that, Also includes: An adhesive material is coated on the side of the flexible film facing the imprinting platform; After the flexible film is removed, the microstructured imprinted adhesive layer remains on the flexible film.

19. The nanoimprint apparatus according to claim 11 or 13, characterized in that, The nanoimprint device, when in use, includes: After forming an imprinting adhesive layer on the wafer, it is placed on the imprinting platform; The flexible membrane tension adjustment component is adjusted to a first height so that the tension of the flexible membrane meets the requirements for tautness. The flexible film tension adjustment component is adjusted to the second height, and the imprint roller is controlled to apply pressure to the flexible film, so that the flexible film and the imprint adhesive on the wafer come into contact; and the imprint roller is continued to be controlled to roll in a direction away from the flexible film fixing component to apply pressure to the flexible film, so that the microstructure on the flexible film is transferred to the imprint adhesive; During the imprinting process, the tension of the flexible film remains at zero.

20. The nanoimprint apparatus according to claim 14, characterized in that, Also includes: Before imprinting, the alignment state of the flexible film is detected by the sensor. If the alignment state of the flexible film does not meet the alignment conditions, the film tension adjustment component is moved by the driving component to adjust the alignment state of the flexible film.

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