Inclined grating preparation method and device

Abstract

The invention provides an inclined grating preparation method and device, and relates to the technical field of grating manufacturing. The method comprises the steps of performing ion beam etching on a hard mask film layer of a to-be-etched part based on a first inclination angle of an inclined table for placing the to-be-etched part to obtain a mask etching part; and performing reactive ion beam etching on the material layer of the mask etching piece based on the second inclination angle of the inclined table on which the mask etching piece is placed to obtain an inclined grating structure. The device comprises a controller used for determining a first inclination angle and a second inclination angle of an inclined table based on a design structure of a to-be-etched part; controlling an inclined table to move to a first inclination angle, and controlling first etching equipment to perform ion beam etching on the hard mask layer of the to-be-etched part to obtain a mask etching part; and controlling the tilting table to move to a second tilting angle, and controlling the second etching equipment to perform reactive ion beam etching on the material layer of the mask etching piece to obtain the tilting grating structure.

Description

Technical Field

[0001] The present application relates to the technical field of grating manufacturing, and in particular, to a method and apparatus for preparing an inclined grating. Background Art

[0002] At present, inclined gratings have important application values in technologies such as augmented reality and virtual reality (AR / VR), mainly reflected in aspects such as waveguide display, polarization control, and light field regulation. As the core component of a waveguide display, an inclined grating can efficiently couple light into or out of the waveguide, improving the display quality and optical efficiency. In terms of polarization selectivity and beam shaping, an inclined grating can achieve precise control of specific light directions and polarization states by regulating structural parameters, optimizing the image contrast and brightness uniformity. Moreover, an inclined grating can achieve high-resolution light field reproduction in a holographic waveguide, promoting the development of AR / VR display technologies.

[0003] Titanium dioxide material has important value in optical applications due to its high refractive index, low optical absorption coefficient, and excellent chemical stability. However, since titanium dioxide is a material with high hardness and extremely stable chemical properties, traditional wet etching is almost ineffective for it, and dry etching is difficult. In existing schemes for preparing inclined gratings, it is impossible to precisely control the morphology of the inclined grating while ensuring the processing accuracy and surface quality, resulting in unfavorable situations such as rough surfaces and insufficient depths in the prepared inclined gratings, thereby leading to poor performance of the inclined gratings and being unable to meet various optical usage requirements. Summary of the Invention

[0004] In view of this, the purpose of the embodiments of the present application is to provide a method and apparatus for preparing an inclined grating to improve the problem of poor performance of inclined gratings existing in the prior art.

[0005] To solve the above problems, in a first aspect, the embodiments of the present application provide a method for preparing an inclined grating, the method including:

[0006] Performing ion beam etching on the hard mask layer of the workpiece to be etched based on a first inclination angle of an inclined table on which the workpiece to be etched is placed, to obtain a mask-etched workpiece;

[0007] Performing reactive ion beam etching on the material layer of the mask-etched workpiece based on a second inclination angle of the inclined table on which the mask-etched workpiece is placed, to obtain an inclined grating structure;

[0008] Wherein, the first inclination angle and the second inclination angle are determined based on the designed structure of the workpiece to be etched, and the designed structure includes the target inclination angle, grating pitch, and depth of the grating.

[0009] In the above implementation process, the etching part to be etched can be etched by a variety of different etching methods to improve the quality of the grating. Moreover, considering the angular requirement differences of different etching methods, the etching part to be etched can be placed on an inclined table with adjustable angle. Based on a preset first inclination angle, the hard mask layer of the etching part to be etched is subjected to ion beam etching to obtain a corresponding mask etching part. Then, the inclined table is adjusted to a second inclination angle, and the material layer of the mask etching part is subjected to reactive ion beam etching to obtain a corresponding inclined grating structure. The first inclination angle and the second inclination angle are determined based on the target inclination angle, grating pitch, depth, etc. of the etching part to be etched, so as to select an appropriate angle for etching according to actual design requirements. Different etching methods can be used based on the characteristics of the material, and different inclination angles can be selected to etch different layer structures, effectively reducing adverse situations such as rough surface and insufficient depth of the inclined grating structure, improving the processing accuracy, surface quality of the inclined grating structure, and the control accuracy of the grating morphology, thereby optimizing the working performance of the inclined grating structure and meeting the usage requirements of various optical application scenarios.

[0010] Optionally, the method further includes:

[0011] Based on the target inclination angle, determining the second inclination angle of the inclined table; wherein, the second inclination angle is the same as the target inclination angle;

[0012] Based on the second inclination angle, determining the first inclination angle of the inclined table; wherein, the angular difference between the first inclination angle and the second inclination angle is less than or equal to a preset threshold.

[0013] In the above implementation process, considering the inclined etching requirement of reactive ion beam etching, the corresponding same angle can be determined as the second inclination angle of reactive ion beam etching according to the target inclination angle in the design structure of the etching part to be etched, so that the inclination angle of the finally etched inclined grating structure meets the design requirements. Moreover, in order to facilitate the realization of the inclined grating structure, the first inclination angle for pre - ion beam etching can be determined according to the second inclination angle, and the angular difference between the first inclination angle and the second inclination angle is less than or equal to a preset threshold, so as to perform preliminary inclined etching through ion beam etching of the hard mask layer, reduce the difficulty of subsequent reactive ion beam etching, and improve the efficiency of reactive ion beam etching. The appropriate inclination angle can be selected for etching at each etching stage based on actual design requirements, effectively improving the overall etching efficiency and effect.

[0014] Optionally, the step of performing ion beam etching on the hard mask layer of the etching part to be etched based on the first inclination angle of the inclined table on which the etching part to be etched is placed to obtain a mask etching part includes:

[0015] Determine the first etching parameters for ion beam etching according to the design structure of the workpiece to be etched; wherein, the first etching parameters include the first gas type, ion beam energy, first power, and etching pattern;

[0016] Based on the first etching parameters, perform ion beam etching on the hard mask layer on the surface of the workpiece to be etched at the first inclination angle to obtain the masked etched workpiece.

[0017] In the above implementation process, during ion beam etching, the first etching parameters for etching the hard mask layer of the workpiece to be etched can be determined according to the design structure of the workpiece to be etched, so as to perform ion beam etching on the hard mask layer on the surface of the workpiece to be etched at the first inclination angle according to the first etching parameters to obtain the corresponding masked etched workpiece. The parameters such as gas, energy, power, and pattern during etching can be set according to the actual design requirements, effectively improving the pertinence and effectiveness of ion beam etching.

[0018] Optionally, the workpiece to be etched includes: a substrate, a material layer, a hard mask layer, and a glue layer;

[0019] The workpiece to be etched is prepared by the following method:

[0020] Deposit or sputter the material layer on the substrate according to the design structure; wherein, the material layer includes a titanium dioxide film layer;

[0021] Deposit or sputter the hard mask layer on the material layer according to the design structure;

[0022] Coat the glue layer on the hard mask layer according to the design structure to obtain the workpiece to be etched.

[0023] In the above implementation process, a corresponding workpiece to be etched with a multi-layer structure can be prepared according to the actual design requirements. Select appropriate materials based on the design structure, deposit or sputter the corresponding material layer on the substrate, then deposit or sputter the corresponding hard mask layer on the material layer based on the design structure, and finally coat the corresponding glue layer on the hard mask layer based on the design structure to display the processed image through the glue layer to obtain the corresponding workpiece to be etched. A workpiece to be etched with corresponding materials and structures can be prepared according to the design requirements of the actual application scenario, meeting various different application requirements.

[0024] Optionally, the method further includes:

[0025] Perform graphic processing on the glue layer based on the design structure to obtain the etching pattern.

[0026] In the above implementation process, the pattern for etching can be determined according to the design structure of the workpiece to be etched, so as to perform pattern processing on the glue layer on the surface of the workpiece to be etched, and obtain the etching pattern corresponding to the etching. The subsequent etching process of the workpiece to be etched can be carried out according to the etching pattern, effectively improving the effectiveness and accuracy of the shape of the inclined grating structure obtained by etching.

[0027] Optionally, the reactive ion beam etching of the material layer of the mask etching part based on the second inclination angle of the inclined table on which the mask etching part is placed to obtain an inclined grating structure includes:

[0028] Determine the second etching parameters for reactive ion beam etching according to the design structure of the workpiece to be etched; wherein, the second etching parameters include the second gas type, gas flow rate, gas ratio, chamber pressure, temperature and second power;

[0029] Based on the second etching parameters, perform reactive ion beam etching on the material layer of the mask etching part at the second inclination angle to obtain the inclined grating structure.

[0030] In the above implementation process, during reactive ion beam etching, the second etching parameters for etching the material layer of the mask etching part can be determined according to the design structure of the workpiece to be etched, so as to perform reactive ion beam etching on the exposed material layer of the mask etching part at the second inclination angle according to the second etching parameters, and obtain the corresponding inclined grating structure. The parameters such as gas type, gas flow rate, gas ratio, chamber pressure, temperature, power, etc. during etching can be set according to actual design requirements, effectively improving the pertinence and effectiveness of reactive ion beam etching.

[0031] Optionally, the method further includes:

[0032] Perform matching in the parameter database based on the design structure of the workpiece to be etched;

[0033] If a historical structure with a similarity higher than the preset similarity threshold to the design structure is matched, then determine the first inclination angle, the second inclination angle and the etching parameters based on the historical etching parameters and historical inclination angle of the historical structure.

[0034] In the above implementation process, considering the requirements of batch preparation, the parameters of multiple historical design structures can be stored in a parameter database. Before preparation, based on the design structure of the workpiece to be etched, a match can be made in the parameter database. If a historical structure with high similarity to the design structure is matched, the historical etching parameters and historical tilt angles of the historical structure are extracted to directly determine the first tilt angle, the second tilt angle, and the etching parameters corresponding to different etching methods required for etching. The determination efficiency of the tilt angle and etching parameters can be effectively improved through database matching, thereby improving the overall etching efficiency, and it is applicable to various batch preparation application scenarios.

[0035] Optionally, the method further includes:

[0036] Before reactive ion beam etching, perform degumming and cleaning on the mask etching workpiece;

[0037] After obtaining the tilted grating structure, perform mask removal and cleaning on the tilted grating structure.

[0038] In the above implementation process, before reactive ion beam etching, degumming and cleaning can be performed on the mask etching workpiece obtained by ion beam etching to reduce the adverse effects of the glue layer on the surface layer of the mask etching workpiece or materials such as impurities generated by ion beam etching on subsequent reactive ion beam etching. After reactive ion beam etching to obtain the corresponding tilted grating structure, mask removal and cleaning can also be performed on the tilted grating structure to reduce the adverse effects of residual hard mask materials and impurities adhering to the tilted grating structure on the tilted grating structure. The intermediate workpiece and the resultant workpiece during the etching process can be cleaned, effectively reducing the adverse effects of impurities on the tilted grating structure, and improving the smoothness and shape accuracy of the grating surface of the finally cleaned tilted grating structure.

[0039] In a second aspect, an embodiment of the present application further provides a tilted grating preparation device, and the device includes: a controller, a tilt table, a first etching device, and a second etching device;

[0040] The tilt table is used to place the workpiece to be etched;

[0041] The controller is used to determine the first tilt angle and the second tilt angle of the tilt table based on the design structure of the workpiece to be etched; wherein, the design structure includes the target tilt angle, grating pitch, and depth of the grating;

[0042] The controller is further used to control the tilt table to move to the first tilt angle, and control the first etching device to perform ion beam etching on the hard mask layer of the workpiece to be etched to obtain a mask etching workpiece;

[0043] The controller is further configured to control the tilting stage to move to a second tilting angle, and control the second etching device to perform reactive ion beam etching on the material layer of the mask etching part to obtain a tilted grating structure.

[0044] In the above implementation process, the controller controls the tilting angle of the tilting stage for placing the device. Based on a preset first tilting angle, ion beam etching is performed on the hard mask layer of the part to be etched to obtain a corresponding mask etching part. Then, the tilting stage is controlled to adjust to a second tilting angle, and reactive ion beam etching is performed on the material layer of the mask etching part to obtain a corresponding tilted grating structure. The first tilting angle and the second tilting angle are determined based on the target tilting angle, grating pitch, depth, etc. of the part to be etched, so as to select an appropriate angle for etching treatment according to actual design requirements.

[0045] Optionally, the tilting stage is configured as a tabletop structure with an adjustable tilting angle, and the adjustable angle range of the tilting stage is: 0° - 70°;

[0046] The tilting stage is made of corrosion-resistant material;

[0047] A fixing structure is provided on the tilting stage, and the fixing structure is used to fix the part to be etched and the mask etching part.

[0048] In the above implementation process, the tilting stage is configured as a tabletop structure with an adjustable tilting angle, and the adjustable angle range between the tilting stage and the horizontal plane is 0° - 70° to meet the preparation requirements of various different tilted gratings. Considering the corrosion of gases in the etching situation, the tilting stage is made of corrosion-resistant material. And considering that when placed obliquely, the device is likely to slide due to the influence of gravity, resulting in adverse situations such as device misalignment. Therefore, a corresponding fixing structure can also be provided on the tilting stage to fix the part to be etched and the mask etching part, so that the part to be etched and the mask etching part can be etched at a stable position, further improving the accuracy and effectiveness during etching.

[0049] In a third aspect, an embodiment of the present application further provides a computer program product, where the computer program product includes computer programs / instructions, and when the computer programs / instructions are executed by a processor, the steps in any one of the methods described in the first aspect above are implemented.

[0050] In summary, the embodiment of the present application provides a method and device for preparing a tilted grating, which can, based on the characteristics of the material, use different etching methods, select different tilting angles to etch different layer structures, effectively reduce adverse situations such as rough surface and insufficient depth of the tilted grating structure, improve the processing accuracy, surface quality and control accuracy of the grating morphology of the tilted grating structure, thereby optimizing the working performance of the tilted grating structure and meeting the usage requirements of various optical application scenarios. Brief Description of the Drawings

[0051] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0052] Figure 1 Schematic flowchart of the first method for preparing an inclined grating provided by an embodiment of the present application;

[0053] Figure 2 Schematic flowchart of the second method for preparing an inclined grating provided by an embodiment of the present application;

[0054] Figure 3 Schematic detailed flowchart of step S100 provided by an embodiment of the present application;

[0055] Figure 4 Schematic flowchart of the third method for preparing an inclined grating provided by an embodiment of the present application;

[0056] Figure 5 Schematic detailed flowchart of step S200 provided by an embodiment of the present application;

[0057] Figure 6 Schematic flowchart of the fourth method for preparing an inclined grating provided by an embodiment of the present application;

[0058] Figure 7 Schematic flowchart of the fifth method for preparing an inclined grating provided by an embodiment of the present application;

[0059] Figure 8 Cross-sectional scanning electron microscope image of an inclined grating prepared according to an embodiment of the present application;

[0060] Figure 9 Schematic structural diagram of an inclined grating preparation device provided by an embodiment of the present application.

[0061] Reference numerals: 710 - Controller; 720 - Tilting table; 730 - First etching device; 740 - Second etching device. Detailed Description of the Embodiments

[0062] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the embodiments of the present application.

[0063] Since titanium dioxide belongs to a material with high hardness and extremely stable chemical properties, traditional wet etching is almost ineffective for it, while dry etching is difficult. The main reasons include: 1. Titanium dioxide has strong chemical inertness and very stable chemical properties. Its crystal structure (such as rutile type and anatase type) has strong bond energy, resulting in a low chemical reaction rate in a plasma environment. Traditional dry etching requires selecting gases that can react efficiently with titanium dioxide (such as fluorine-based gases or chlorine-based gases), but the etching rate is usually still slow. 2. Low etching selectivity: Titanium dioxide usually has low etching selectivity for mask materials (such as photoresist, silicon dioxide). In order to avoid premature depletion of the mask layer, a hard mask with high hardness (such as chromium or alumina) is usually required, further increasing the process complexity. 3. In dry etching, titanium dioxide is prone to an increase in surface roughness due to ion bombardment and the residue of etching products, which will have a negative impact on the performance of high-precision optical devices (such as gratings). 4. Poor volatility of etching by-products: The etching by-products of titanium dioxide (such as titanium tetrafluoride and titanium tetrachloride) have low volatility, may deposit in the etching chamber, resulting in a decrease in etching efficiency and increasing the difficulty of equipment cleaning.

[0064] Therefore, in the existing schemes for preparing tilted gratings, it is impossible to accurately control the morphology of the tilted grating while ensuring the processing accuracy and surface quality, resulting in adverse situations such as rough surfaces and insufficient depth in the prepared tilted gratings, thus leading to poor performance of the tilted gratings and being unable to meet various optical usage requirements.

[0065] To solve the above problems, the embodiments of the present application provide a method and device for preparing a tilted grating, which can, based on the characteristics of the material, use different etching methods, select different tilt angles to etch different layer structures, effectively reducing adverse situations such as rough surfaces and insufficient depth in the tilted grating structure, improving the processing accuracy, surface quality, and control accuracy of the grating morphology of the tilted grating structure, thereby optimizing the working performance of the tilted grating structure and meeting the usage requirements of various optical application scenarios.

[0066] Please refer to Figure 1 , Figure 1 which is a schematic flowchart of the first method for preparing a tilted grating provided by the embodiments of the present application. The method may include steps S100 - S200.

[0067] Step S100: Based on the first tilt angle of the tilt table on which the etched part to be etched is placed, perform ion beam etching on the hard mask layer of the etched part to be etched to obtain an etched mask part.

[0068] Among them, the etched part to be etched can be etched by a variety of different etching methods to improve the quality of the grating. And considering the angular requirement differences of different etching methods, the etched part to be etched can be placed on a tilt table with adjustable angle, and ion beam etching is performed on the hard mask layer of the etched part to be etched based on the preset first tilt angle to obtain the corresponding etched mask part.

[0069] It should be noted that ion beam etching (IBE) uses inert gas (such as argon ions) to bombard the surface of the material in a vacuum environment, and removes the material through physical sputtering (kinetic energy transfer) to achieve physical etching. The vertical etching rate of ion beam etching is much higher than the lateral one, which is suitable for high-precision pattern transfer.

[0070] Step S200: Based on the second tilt angle of the tilt table on which the etched mask part is placed, perform reactive ion beam etching on the material layer of the etched mask part to obtain an inclined grating structure.

[0071] Among them, the tilt table is adjusted to the second tilt angle, and reactive ion beam etching is performed on the material layer of the etched mask part to obtain the corresponding inclined grating structure.

[0072] It should be noted that for titanium dioxide materials with high hardness and difficult to etch, it is difficult for photoresist to be directly used as a mask to withstand long-term dry etching. Especially for sub-wavelength tilted gratings used in AR (Augmented Reality) / VR (Virtual Reality), the thickness of the photoresist is often controlled at about 100 nm due to the limitation of high resolution, which will limit the etching depth of the titanium dioxide material. With the help of a hard mask (such as silicon dioxide), the processing stability can be improved, but it is also difficult to increase the etching selectivity for titanium dioxide, resulting in a slow etching rate of titanium dioxide and a greatly limited etching depth (usually in the depth of dozens of nanometers). Therefore, due to the lack of a mask layer with high selectivity, it is difficult to achieve a large etching depth of the titanium dioxide tilted grating and obtain an ideal etching morphology if only ion beam etching is used. Therefore, in order to achieve an ideal etching depth, after ion beam etching, the present application also uses reactive ion beam etching to perform a re-etching treatment on the mask etching part obtained by ion beam etching to optimize the etching morphology of the tilted grating structure. Two different dry etching processes can be combined to fabricate gratings, achieving high tilt angles, sub-wavelength periods and shape control of the tilted grating structure, overcoming problems such as low etching selectivity and difficult morphology control, and being applicable to the fabrication of various optical elements with fast etching speed, high etching efficiency and low etching loss. Reactive ion beam etching can introduce reactive gases (such as carbon tetrafluoride, chlorine, oxygen, etc.) into the ion beam. The ion bombardment and chemical reaction act synergistically. The material is removed based on the ion kinetic energy, and etching is achieved based on the generation of volatile products by the reaction gas and the material (such as silicon tetrafluoride etching silicon). High-selectivity etching for specific materials (such as silicon dioxide / silicon) can be achieved by adjusting the gas composition. Moreover, the chemical reaction enhances the etching rate, and at the same time, the directionality of the ion beam is controlled. The surface damage of the etched part can be reduced by reducing the ion energy, and devices with high aspect ratio and high selectivity can be etched.

[0073] Optionally, considering the differences in the angular requirements of different etching methods, the first tilt angle for ion beam etching and the second tilt angle for reactive ion beam etching are determined based on the design structure of the workpiece to be etched. The first tilt angle and the second tilt angle are the included angles between the plane where the device is placed on the tilt table and the horizontal plane. The design structure may include the target tilt angle of the grating (the included angle between the tilted grating structure and the vertical direction perpendicular to the horizontal substrate, such as 0° - 60°), the grating shape (the shape and size of the grating, etc.), the pitch (the distance between adjacent gratings, i.e., the period distance, for example, the period of the grating is 100 nm - 1000 nm), the duty cycle (such as 0.2 - 0.7, etc.), and the depth (the etching depth of the grating), etc. A variety of parameters related to the tilted grating structure. The design structure can be designed according to actual functional requirements, such as the structure of the tilted grating designed based on the usage requirements of AR / VR. The design structure can be used as an ideal reference structure for the tilted grating structure during the etching process.

[0074] In Figure 1 In the illustrated embodiment, based on the characteristics of the material, different etching methods can be used, and different tilt angles can be selected to etch different layer structures, effectively reducing adverse situations such as rough surfaces and insufficient depths of the tilted grating structure, improving the processing accuracy, surface quality, and control accuracy of the grating morphology of the tilted grating structure, thereby optimizing the working performance of the tilted grating structure and meeting the usage requirements of various optical application scenarios.

[0075] Optionally, please refer to Figure 2 , Figure 2 which is a schematic flowchart of the second method for preparing a tilted grating provided by an embodiment of the present application. This method may further include steps S310 - S320.

[0076] Step S310: Determine the second tilt angle of the tilt table based on the target tilt angle.

[0077] Among them, considering the tilt etching requirements and vertical etching characteristics of reactive ion beam etching, the corresponding same angle can be determined as the second tilt angle of reactive ion beam etching according to the target tilt angle in the design structure of the workpiece to be etched, so that the tilt angle of the finally etched tilted grating structure meets the design requirements. The second tilt angle is the same as the target tilt angle. For example, when the target tilt angle in the design structure is 60°, the second tilt angle is also set to 60°, so that the mask etching workpiece placed on the tilt table can be etched by the reactive ion beam perpendicular to the placement plane of the tilt table to form a corresponding 60° tilt angle.

[0078] Step S320: Determine the first tilt angle of the tilt table based on the second tilt angle.

[0079] Among them, in order to facilitate the implementation of the tilted grating structure, the first tilt angle for performing ion beam etching in advance can be determined according to the second tilt angle, and the angular difference between the first tilt angle and the second tilt angle is less than or equal to a preset threshold, so as to perform preliminary tilted etching through the ion beam etching of the hard mask layer, reduce the difficulty of subsequent reactive ion beam etching, and improve the efficiency of reactive ion beam etching.

[0080] Optionally, the preset threshold can be selected according to the actual situation. For example, the preset threshold can be set to 5°. When the second tilt angle is 30°, the first tilt angle can be set to 25°-35°, so that the hard mask layer can first perform preliminary tilted etching, reduce the blocking of the hard mask layer during subsequent reactive ion beam etching, and thus reduce the difficulty of subsequent reactive ion beam etching.

[0081] Optionally, the first tilt angle and the second tilt angle can also be set to the same angle.

[0082] In Figure 2 the illustrated embodiment, it is possible to select an appropriate tilt angle for etching at each etching stage based on the actual design requirements, effectively improving the overall etching efficiency.

[0083] Optionally, please refer to Figure 3 , Figure 3 which is a detailed flowchart of step S100 provided by an embodiment of the present application. Step S100 may include steps S110-S120.

[0084] Step S110, determine the first etching parameter of the ion beam etching according to the design structure of the workpiece to be etched.

[0085] Among them, when performing ion beam etching, the first etching parameter for etching the hard mask layer of the workpiece to be etched can be determined according to the design structure of the workpiece to be etched.

[0086] Optionally, the first etching parameter may include the first gas type (such as argon) of the gas used in the ion beam etching, the ion beam energy (such as an ion beam current of 100 mA-200 mA), the first power used by the process equipment (such as 100 W-400 W), and the etching pattern (the pattern of the area to be etched and the area not to be etched), etc.

[0087] It should be noted that the first etching parameter may also include the etching angle of the ion beam etching, and the etching angle can be set according to the target tilt angle and the first tilt angle to achieve preliminary tilted etching in the ion beam etching stage.

[0088] Step S120, based on the first etching parameter, perform ion beam etching on the hard mask layer on the surface of the workpiece to be etched at the first tilt angle to obtain a mask-etched workpiece.

[0089] Among them, the hard mask layer on the surface of the workpiece to be etched at the first tilt angle can be etched by an ion beam according to the first etching parameter to obtain a corresponding masked etched workpiece.

[0090] Optionally, based on the ion beam etching process, anisotropic etching can be performed on the hard mask layer on the surface of the workpiece to be etched on the basis of the first etching parameter to form a corresponding masked etched workpiece with a hard mask pattern.

[0091] In Figure 3 In the illustrated embodiment, parameters such as gas, energy, power, and pattern during etching can be set according to actual design requirements, effectively improving the pertinence and effectiveness of ion beam etching.

[0092] It should be noted that the workpiece to be etched may include: a substrate, a material layer, a hard mask layer, and a glue layer. A corresponding workpiece to be etched with a multi-layer structure can be prepared according to actual design requirements. Optionally, please refer to Figure 4 , Figure 4 FIG. is a schematic flowchart of a third method for preparing an inclined grating provided in an embodiment of the present application. This method may further include steps S410-S430.

[0093] Step S410, depositing or sputtering a material layer on the substrate according to the designed structure.

[0094] Among them, a suitable material can be selected based on the designed structure, and the corresponding material layer can be deposited or sputtered on the substrate. Considering the optical use requirements of high refractive index, low optical absorption coefficient, and stability, the material layer may include a titanium dioxide film layer. The substrate may be a silicon wafer or a transparent substrate, such as quartz glass or a silicon wafer. First, ultrasonic cleaning (sequentially using acetone, ethanol, and deionized water) can be performed, and plasma cleaning can be used to remove organic contaminants on the surface of the substrate. On the silicon wafer or transparent substrate, a sample of the titanium dioxide film layer can be deposited by atomic layer deposition or sputtering process. The thickness of the material layer can be designed and modified based on actual optical requirements. For example, the thickness of the material layer is set to 100 nm - 1000 nm, etc.

[0095] Optionally, an atomic layer deposition (ALD) or sputtering deposition process can be used to deposit a titanium dioxide thin film with a thickness of 100 nm - 1000 nm. The process parameters of ALD may include: deposition temperature 150°C - 200°C, precursors such as tetrakis(dimethylamino)titanium (TDMAT), titanium tetrachloride, and water. The process parameters of sputtering may include: the target is a titanium dioxide target, the gas is a mixture of oxygen and argon, the power is 200 W - 400 W, and the sputtering pressure is 35 mTorr.

[0096] Step S420: Deposit or sputter on the material layer according to the design structure to obtain a hard mask layer.

[0097] Among them, the corresponding hard mask layer can be deposited or sputtered on the material layer based on the design structure. For example, hard mask materials such as chromium or alumina can be grown on the material layer through sputtering or deposition processes as the hard mask layer. The thickness of the hard mask layer can also be designed and modified based on actual optical requirements. For example, the thickness of the hard mask layer is set to 10nm - 100nm, etc.

[0098] Optionally, a hard mask layer with a certain thickness can be deposited on the titanium dioxide thin film. For example, a chromium film layer or an alumina film layer can be deposited using a magnetron sputtering process, and the deposition rate is controlled to be 0.5nm / s - 2nm / s.

[0099] Step S430: Coat a glue layer on the hard mask layer according to the design structure to obtain a workpiece to be etched.

[0100] Among them, the corresponding glue layer can be coated on the hard mask layer based on the design structure to display the processed image through the glue layer, and the corresponding workpiece to be etched is obtained.

[0101] Exemplarily, a photoresist or a nanoimprint resist can be spin-coated on the hard mask layer as the glue layer. The thickness of the glue layer can also be designed and modified based on actual optical requirements. For example, the thickness of the glue layer is set to 80nm - 300nm, etc.

[0102] Optionally, based on the design structure, the glue layer can also be processed graphically to obtain an etching pattern. The subsequent etching process of the workpiece to be etched can be carried out according to the etching pattern, effectively improving the effectiveness and accuracy of the shape of the etched tilted grating structure. For example, methods such as electron beam lithography, laser interference, laser direct writing, or projection lithography are used to expose the designed periodic tilted grating structure, or graphical processing is carried out through the nanoimprint method. Finally, a periodic grating pattern of the photoresist or the nanoimprint resist is obtained as the etching pattern for reference during etching, so as to use the patterned photoresist or nanoimprint resist to etch the hard mask material through a preset gas in the ion beam etching process and transfer the pattern to the hard mask material.

[0103] In Figure 4 the illustrated embodiment, a workpiece to be etched with corresponding materials and structures can be prepared according to the design requirements of the actual application scenario, meeting various different application requirements.

[0104] Optionally, please refer to Figure 5 , Figure 5 which is a detailed process schematic diagram of step S200 provided by an embodiment of the present application. Step S200 may include steps S210 - S220.

[0105] Step S210: Determine the second etching parameters for reactive ion beam etching according to the designed structure of the workpiece to be etched.

[0106] Among them, when performing reactive ion beam etching, the second etching parameters for etching the material layer of the mask etching workpiece can be determined according to the designed structure of the workpiece to be etched.

[0107] Exemplarily, the second etching parameters may include the second gas type of the gas used in reactive ion beam etching (such as one or more of sulfur hexafluoride, trifluoromethane, carbon tetrafluoride, argon, oxygen), gas flow rate (such as 10 sccm - 100 sccm), gas ratio (the proportion of each gas when there are multiple types of gases), the chamber pressure during reactive ion beam etching, and the second power used by the process equipment (such as 100 W - 400 W, etc.), and may also include various parameters such as the temperature inside the chamber during reactive ion beam etching.

[0108] It should be noted that the etching angle during reactive ion beam etching can be a fixed angle to achieve inclined etching through the second inclination angle of the tilting table.

[0109] Step S220: Based on the second etching parameters, perform reactive ion beam etching on the material layer of the mask etching workpiece at the second inclination angle to obtain an inclined grating structure.

[0110] Among them, reactive ion beam etching can be performed on the exposed material layer of the mask etching workpiece according to the second etching parameters to obtain a corresponding inclined grating structure.

[0111] Optionally, based on the reactive ion beam etching process, on the basis of the second etching parameters, the exposed material layer of the mask etching workpiece can be etched using the hard mask pattern on the surface of the mask etching workpiece to obtain an inclined grating structure with an etching depth.

[0112] In Figure 5 the illustrated embodiment, parameters such as the gas type, gas flow rate, gas ratio, and power during etching can be set according to actual design requirements, effectively improving the pertinence and effectiveness of reactive ion beam etching.

[0113] Optionally, please refer to Figure 6 , Figure 6 which is a schematic flowchart of the fourth method for preparing an inclined grating provided by an embodiment of the present application. This method may further include steps S510 - S520.

[0114] Step S510: Perform matching in the parameter database based on the designed structure of the workpiece to be etched.

[0115] Among them, considering the requirements of batch preparation, the parameters of multiple historical design structures can be stored in a parameter database. Before preparation, matching can be performed in the parameter database based on the design structure of the part to be etched.

[0116] Optionally, the historical structures in the parameter database can also include various parameters related to the tilted grating structure, such as the tilt angle of the grating, the grating shape, the spacing, the duty cycle, and the depth. When performing the matching, multiple parameters in the design structure can be compared one by one with multiple parameters in the historical structure to determine whether there is a historical structure in the parameter database that matches the design structure.

[0117] Step S520, if a historical structure with a similarity higher than a preset similarity threshold to the design structure is matched, determine the first tilt angle, the second tilt angle, and the etching parameters based on the historical etching parameters and the historical tilt angle of the historical structure.

[0118] Among them, if a historical structure with a similarity higher than a preset similarity threshold to the design structure is matched. It indicates that the design structure has a historical structure with high similarity, then extract the historical etching parameters and the historical tilt angle of the historical structure to directly determine the first tilt angle, the second tilt angle, and the etching parameters corresponding to different etching methods required during etching.

[0119] Optionally, the similarity threshold can include the similarity of multiple parameters. For example, the tilt angle of the historical structure is the same as the target tilt angle of the design structure, and the grating shape, the spacing, the duty cycle, and the depth, etc. have relatively high numerical ratios. For example, the interval numerical ratio threshold of the grating interval of the historical structure to the grating interval of the design structure is set to be greater than or equal to 98%, etc., so that when the design structure and the historical structure are highly similar, the historical etching parameters and the historical tilt angle of the historical structure are used as the first tilt angle, the second tilt angle, and the etching parameters corresponding to different etching methods required during etching.

[0120] In Figure 6 the embodiment shown, the determination efficiency of the tilt angle and the etching parameters can be effectively improved through database matching, thereby improving the overall etching efficiency, and it is applicable to various batch preparation application scenarios.

[0121] Optionally, please refer to Figure 7 , Figure 7 which is a schematic flowchart of the fifth method for preparing a tilted grating provided by the embodiment of the present application. This method may further include steps S610 - S620.

[0122] Step S610, before performing reactive ion beam etching, perform degumming and cleaning on the mask etching part.

[0123] Among them, before performing reactive ion beam etching, the mask etching part obtained by ion beam etching can be subjected to degumming and cleaning treatments to reduce the adverse effects on subsequent reactive ion beam etching caused by the glue layer on the surface layer of the mask etching part or materials such as impurities generated by ion beam etching.

[0124] Optionally, a degumming solution can be used to remove the photoresist or nanoimprint glue remaining on the hard mask after etching, and the mask etching part can be cleaned with solutions such as acetone and deionized water.

[0125] Step S620, after obtaining the inclined grating structure, perform mask removal and cleaning treatments on the inclined grating structure.

[0126] Among them, after performing reactive ion beam etching to obtain the corresponding inclined grating structure, mask removal and cleaning treatments can also be performed on the inclined grating structure to reduce the adverse effects on the inclined grating structure caused by the remaining hard mask materials and impurities adhering to the inclined grating structure.

[0127] Optionally, the remaining hard mask materials after etching can be removed by a chromium-removing solution or a hydrofluoric acid solution, etc., and then the inclined grating structure can be cleaned with solutions such as acetone and deionized water. After cleaning, a plasma ashing process can also be used to further clean the grating surface.

[0128] In Figure 7 the shown embodiment, the intermediate parts and the result parts during the etching process can be cleaned, effectively reducing the adverse effects on the inclined grating structure caused by impurities, and improving the smoothness and shape accuracy of the grating surface of the finally cleaned inclined grating structure.

[0129] Please refer to Figure 8 , Figure 8 which is a cross-sectional scanning electron microscope (SEM) image of an inclined grating prepared according to an embodiment of the present application. The prepared inclined grating is a titanium dioxide inclined grating. As Figure 8 can be seen, the grating period of the inclined grating is 200 nm, the duty cycle is 0.5, the target tilt angle is 25°, and the etching vertical height is 300 nm. The side walls of the etched titanium dioxide inclined grating are smooth and the two side walls are parallel, reflecting the reliability and accuracy of the inclined grating preparation method provided by the embodiment of the present application.

[0130] Please refer to Figure 9 , Figure 9 which is a schematic structural diagram of an inclined grating preparation device provided by an embodiment of the present application. The inclined grating preparation device includes: a controller 710, a tilt table 720, a first etching device 730, and a second etching device 740;

[0131] The tilt table 720 is used to place the part to be etched;

[0132] A controller 710 is configured to determine a first tilt angle and a second tilt angle of a tilt stage 720 based on a design structure of a workpiece to be etched. The design structure includes a target tilt angle, a grating pitch, and a depth of a grating.

[0133] The controller 710 is further configured to control the tilt stage 720 to move to the first tilt angle and control a first etching device 730 to perform ion beam etching on a hard mask layer of the workpiece to be etched, thereby obtaining a masked etched workpiece.

[0134] The controller 710 is further configured to control the tilt stage 720 to move to the second tilt angle and control a second etching device 740 to perform reactive ion beam etching on a material layer of the masked etched workpiece, thereby obtaining an inclined grating structure.

[0135] It should be noted that the first etching device 730 may be a process device with an ion beam etching function, and the second etching device 740 may be a process device with a reactive ion beam etching function. The controller 710 may be connected to the first etching device 730, the second etching device 740, and the tilt stage 720 through a network, Bluetooth, etc., so as to control the first etching device 730, the second etching device 740, and the tilt stage 720.

[0136] Optionally, the controller 710 may be an electronic device with a logical computing function, such as a server, a personal computer (PC), a tablet computer, a smart phone, a personal digital assistant (PDA), etc.

[0137] In an alternative embodiment, the controller 710 is specifically configured to: determine the second tilt angle of the tilt stage 720 based on the target tilt angle, where the second tilt angle is the same as the target tilt angle; determine the first tilt angle of the tilt stage 720 based on the second tilt angle, where the angular difference between the first tilt angle and the second tilt angle is less than or equal to a preset threshold.

[0138] In an alternative embodiment, the controller 710 is specifically configured to: determine first etching parameters for ion beam etching according to the design structure of the workpiece to be etched. The first etching parameters include a first gas type, an ion beam energy, a first power, and an etching pattern. The first etching device 730 is specifically configured to perform ion beam etching on the hard mask layer on the surface of the workpiece to be etched at the first tilt angle based on the first etching parameters, thereby obtaining a masked etched workpiece.

[0139] In an alternative embodiment, the component to be etched includes: a substrate, a material layer, a hard mask layer, and a photoresist layer; the inclined grating preparation device may further include a preparation component, which is configured to: deposit or sputter a material layer on the substrate according to the designed structure; wherein the material layer includes a titanium dioxide film layer; deposit or sputter a hard mask layer on the material layer according to the designed structure; coat a photoresist layer on the hard mask layer according to the designed structure to obtain the component to be etched.

[0140] In an alternative embodiment, the preparation component is further configured to: perform graphic processing on the photoresist layer based on the designed structure to obtain an etching pattern.

[0141] In an alternative embodiment, the controller 710 is specifically configured to: determine the second etching parameters of reactive ion beam etching according to the designed structure of the component to be etched; wherein the second etching parameters include the second gas type, gas flow rate, gas ratio, chamber pressure, temperature, and second power; the second etching device 740 is specifically configured to: perform reactive ion beam etching on the material layer of the mask etching component at the second inclination angle based on the second etching parameters to obtain an inclined grating structure.

[0142] In an alternative embodiment, the controller 710 is further configured to: perform matching in the parameter database based on the designed structure of the component to be etched; if a historical structure with a similarity higher than the preset similarity threshold to the designed structure is matched, determine the first inclination angle, the second inclination angle, and the etching parameters based on the historical etching parameters and the historical inclination angle of the historical structure.

[0143] In an alternative embodiment, the inclined grating preparation device may further include a cleaning component, which is configured to: perform photoresist removal and cleaning on the mask etching component before reactive ion beam etching; perform mask removal and cleaning on the inclined grating structure after obtaining the inclined grating structure.

[0144] It should be noted that the tilt table 720 is configured as a tabletop structure with an adjustable tilt angle, such as a lifting table with controllable unilateral angle, etc. The adjustable angle range of the tilt table 720 can be: 0° - 70°, to meet the preparation requirements of various different inclined gratings.

[0145] Optionally, considering the corrosion of the gas in the etching situation, the tilt table 720 can be made of corrosion-resistant materials. For example, the tilt table 720 can be made of carbon fiber or graphite, etc., so that the tilt table 720 does not deform and no pollutants are generated during the two dry etching processes.

[0146] It should be noted that considering that when placed obliquely, the device is prone to slipping under the influence of gravity, resulting in adverse situations such as device misalignment. Therefore, a fixing structure can also be provided on the inclined table 720, and the fixing structure is used to fix the device to be etched and the mask etching device.

[0147] Exemplarily, the fixing structure can be set as a fixing block, a fixing groove or other structures with a fixing function.

[0148] The embodiment of the present application also provides a computer program product, which includes computer programs / instructions. When the computer programs / instructions are executed by a processor, the steps in the method described in the method for preparing an inclined grating provided by the embodiment of the present application are implemented.

[0149] In several embodiments provided by the present application, it should be understood that the disclosed device can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the block diagrams in the drawings show the possible architectures, functions, and operations of the device according to multiple embodiments of the present application. In this regard, each block in the block diagram can represent a module, a program segment, or a part of code, and the module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram, as well as the combination of block diagrams, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0150] In addition, in each embodiment of the present application, the various functional modules can be integrated together to form an independent part, or each module can exist alone, or two or more modules can be integrated to form an independent part.

[0151] When the above-mentioned functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art or a part of this technical solution can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0152] The above are only the embodiments of this application and are not used to limit the protection scope of this application. For those skilled in the art, this application can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included in the protection scope of this application. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0153] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in this application, and all should be covered by the protection scope of this application.

[0154] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitations, the elements defined by the statement "including..." do not exclude the existence of additional identical elements in the process, method, article or device including the said elements.

Claims

1. A method for preparing an inclined grating, characterized in that, The method includes: Based on a first inclination angle of an inclined table on which an etching target is placed, performing ion beam etching on a hard mask layer of the etching target to obtain a mask-etched part; Based on a second inclination angle of the inclined table on which the mask-etched part is placed, performing reactive ion beam etching on a material layer of the mask-etched part to obtain an inclined grating structure; Wherein, the first inclination angle and the second inclination angle are determined based on a design structure of the etching target, and the design structure includes a target inclination angle of a grating, a grating pitch, and a depth.

2. The method according to claim 1, wherein The method further includes: Based on the target inclination angle, determining the second inclination angle of the inclined table; wherein, the second inclination angle is the same as the target inclination angle; Based on the second inclination angle, determining the first inclination angle of the inclined table; wherein, an angular difference between the first inclination angle and the second inclination angle is less than or equal to a preset threshold.

3. The method according to claim 1, wherein The performing ion beam etching on the hard mask layer of the etching target based on the first inclination angle of the inclined table on which the etching target is placed to obtain a mask-etched part includes: According to the design structure of the etching target, determining first etching parameters for ion beam etching; wherein, the first etching parameters include a first gas type, an ion beam energy, a first power, and an etching pattern; Based on the first etching parameters, performing ion beam etching on the hard mask layer on the surface of the etching target at the first inclination angle to obtain the mask-etched part.

4. The method according to claim 3, wherein Wherein, The etching target includes: a substrate, a material layer, a hard mask layer, and a glue layer; The etching target is prepared by the following method: According to the design structure, depositing or sputtering the material layer on the substrate; wherein, the material layer includes a titanium dioxide film layer; According to the design structure, depositing or sputtering the hard mask layer on the material layer; According to the design structure, coating the glue layer on the hard mask layer to obtain the etching target.

5. The method according to claim 4, characterized in that, The method further includes: Based on the design structure, performing graphic processing on the glue layer to obtain the etching pattern.

6. The method according to claim 1, wherein The performing reactive ion beam etching on the material layer of the mask-etched part based on the second inclination angle of the inclined table on which the mask-etched part is placed to obtain an inclined grating structure includes: According to the design structure of the etching target, determining second etching parameters for reactive ion beam etching; wherein, the second etching parameters include a second gas type, a gas flow rate, a gas ratio, a chamber pressure, a temperature, and a second power; Based on the second etching parameters, performing reactive ion beam etching on the material layer of the mask-etched part at the second inclination angle to obtain the inclined grating structure.

7. The method according to claim 1, characterized in that The method further includes: Performing matching in a parameter database based on the design structure of the etching target; If a historical structure with a similarity higher than a preset similarity threshold to the design structure is matched, then determining the first inclination angle, the second inclination angle, and the etching parameters based on historical etching parameters and historical inclination angles of the historical structure.

8. The method according to any one of claims 1 to 7, characterized in that, The method further includes: Before performing reactive ion beam etching, the mask etching part is degummed and cleaned; After obtaining the inclined grating structure, the mask of the inclined grating structure is removed and cleaned.

9. An inclined grating preparation device, characterized in that, The device includes: a controller, an inclined table, a first etching device, and a second etching device; The inclined table is used to place the workpiece to be etched; The controller is configured to determine a first inclination angle and a second inclination angle of the inclined table based on the designed structure of the workpiece to be etched; wherein, the designed structure includes the target inclination angle, grating pitch, and depth of the grating; The controller is further configured to control the inclined table to move to the first inclination angle, and control the first etching device to perform ion beam etching on the hard mask layer of the workpiece to be etched, so as to obtain a mask etching part; The controller is further configured to control the inclined table to move to the second inclination angle, and control the second etching device to perform reactive ion beam etching on the material layer of the mask etching part, so as to obtain an inclined grating structure.

10. The device according to claim 9, wherein, Wherein, The inclined table is configured as a tabletop structure with an adjustable inclination angle, and the adjustable angle range of the inclined table is: 0° - 70°; The inclined table is made of corrosion-resistant material; A fixing structure is arranged on the inclined table, and the fixing structure is used to fix the workpiece to be etched and the mask etching part.

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