A method for fabricating a silicon template for a diffractive optical waveguide
By forming grating structures with flush bottoms but different heights on a silicon substrate, or by forming grating material between the pattern gaps in the template pattern film layer, the problem of poor display effect caused by inconsistent grating heights is solved, and the display performance of diffractive waveguides is improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SEEV OPTOELECTRONICS TECHNOLOGY CO LTD
- Filing Date
- 2024-02-07
- Publication Date
- 2026-06-12
Smart Images
Figure CN118259400B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optical technology, and in particular to a method for fabricating a silicon template for a diffractive optical waveguide. Background Technology
[0002] With continuous technological innovation, Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR) have gradually entered industries such as manufacturing and education. Among these, in AR, diffractive waveguides have become a favored optical imaging solution due to their lightweight, wide field of view, and high yield in mass production. To adjust the display effect of diffractive waveguides, the height of the gratings located in different grating regions may vary.
[0003] The fabrication of a diffractive waveguide involves the preparation of a silicon template, the formation of a soft template using silicon template transfer, and the transfer of the pattern on the soft template to an adhesive layer on the waveguide substrate using imprinting. The silicon template preparation mainly involves multiple photolithography and etching processes on the silicon substrate to form coupling grating regions, transition grating regions, and coupling grating regions with a uniform top height and uneven bottom. Therefore, the soft template formed by the transfer from the silicon template has inconsistent grating top heights and uniform bottom heights in different regions. Consequently, different grating regions of the diffractive waveguide formed by the transfer from the soft template have uniform top heights and different adhesive layer thicknesses at the bottom, i.e., inconsistent residual adhesive. This is equivalent to inconsistent thickness within a local area of the waveguide, which increases light scattering when light propagates within the waveguide, ultimately affecting the overall display effect. Summary of the Invention
[0004] This invention provides a method for fabricating a silicon template for a diffractive waveguide. The silicon template is fabricated with different grating heights in different regions but with a flush bottom. In this way, the residual adhesive at the bottom of the diffractive waveguide is consistent, and the display effect of the diffractive waveguide will not be affected by the difference in thickness when the light is transmitted into the interior of the diffractive waveguide.
[0005] To achieve the above objectives, embodiments of the present invention provide a method for fabricating a silicon template for a diffractive optical waveguide, comprising:
[0006] A grating film layer is formed on a silicon substrate, and a photolithography process is performed on the grating film layer based on corresponding photolithography parameters to form a grating structure with different heights and flush bottoms.
[0007] Alternatively, a template pattern film layer is formed on the silicon substrate, and a corresponding grating material is formed between the pattern gaps of the template pattern film layer. The template pattern film layer is then removed to form a grating structure with different bottom flush heights.
[0008] The method for fabricating a silicon template for a diffractive waveguide provided in this invention involves directly forming a grating structure with a flush bottom but different heights on a silicon substrate using photolithography, or forming a corresponding grating material between the pattern gaps of the template pattern film layer based on the corresponding template pattern film layer to form a grating structure with a flush bottom but different heights. In this way, the soft template formed after transfer from the silicon template has a grating structure with a flush top and different bottom heights. When the soft template is then transferred to form a diffractive waveguide, the grating heights of different grating regions on the diffractive waveguide are different, but the bottoms are flush. When light is transmitted to the interior of the diffractive waveguide, the display effect of the diffractive waveguide will not be affected by the difference in thickness.
[0009] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description
[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0011] Figure 1 This is a schematic diagram of the silicon template structure of a diffractive waveguide in the prior art;
[0012] Figure 2 This is a schematic diagram of the structure of a diffraction grating in the prior art;
[0013] Figure 3 This is a schematic diagram of the structure of a diffractive optical waveguide in the prior art;
[0014] Figure 4 This is a schematic diagram of the structure of a silicon template for a diffractive optical waveguide provided in an embodiment of the present invention;
[0015] Figure 5 A flowchart illustrating the fabrication method of a silicon template for a first diffractive optical waveguide provided in an embodiment of the present invention;
[0016] Figure 6 A schematic diagram illustrating the fabrication process of the silicon template for the first type of diffractive optical waveguide provided in this embodiment of the invention;
[0017] Figure 7 A flowchart illustrating the fabrication method of a silicon template for a second diffractive waveguide provided in an embodiment of the present invention;
[0018] Figure 8A schematic diagram illustrating the fabrication process of the silicon template for the second type of diffractive waveguide provided in this embodiment of the invention;
[0019] Figure 9 A flowchart illustrating the fabrication method of a silicon template for a third diffractive optical waveguide provided in this embodiment of the invention;
[0020] Figure 10 A schematic diagram illustrating the fabrication process of a silicon template for a third type of diffractive waveguide provided in an embodiment of the present invention;
[0021] Figure 11 A schematic diagram illustrating the fabrication process of a silicon template for a third type of diffractive waveguide provided in another embodiment of the present invention;
[0022] Figure 12 A flowchart illustrating the fabrication method of a silicon template for a fourth diffractive waveguide provided in this embodiment of the invention;
[0023] Figure 13 A schematic diagram illustrating the fabrication process of the silicon template for the fourth type of diffractive waveguide provided in this embodiment of the invention;
[0024] Figure 14 A flowchart illustrating the fifth method for fabricating a silicon template for a diffractive optical waveguide provided in this embodiment of the invention;
[0025] Figure 15 A schematic diagram illustrating the fabrication process of the silicon template for the fifth type of diffractive waveguide provided in this embodiment of the invention;
[0026] Figure 16 A flowchart illustrating the fabrication method of a silicon template for a sixth diffractive waveguide provided in this embodiment of the invention;
[0027] Figure 17 A schematic diagram illustrating the fabrication process of the silicon template for the sixth type of diffractive waveguide provided in this embodiment of the invention;
[0028] Figure 18 A flowchart illustrating the method for fabricating a silicon template for a seventh diffractive optical waveguide according to an embodiment of the present invention;
[0029] Figure 19 A schematic diagram illustrating the fabrication process of the silicon template for the seventh type of diffractive waveguide provided in this embodiment of the invention;
[0030] Figure 20 A flowchart illustrating the method for fabricating a silicon template for an eighth diffractive waveguide according to an embodiment of the present invention;
[0031] Figure 21 A schematic diagram illustrating the fabrication process of the silicon template for the eighth type of diffractive waveguide provided in this embodiment of the invention;
[0032] Figure 22A flowchart illustrating the preparation method of a silicon template for a ninth diffractive waveguide provided in this embodiment of the invention;
[0033] Figure 23 A schematic diagram illustrating the fabrication process of the silicon template for the ninth type of diffractive waveguide provided in this embodiment of the invention. Detailed Implementation
[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0036] Currently, silicon templates for diffractive waveguides are formed into different grating regions with varying heights through multiple photolithography and etching processes. These different grating regions have flush tops and varying bottom thicknesses (e.g., ...). Figure 1 As shown in h1 / h2 / h3), the soft template formed by silicon template transfer has different grating heights (e.g., h1 / h2 / h3). Figure 2 As shown in h4 / h5 / h6), a template with a flat bottom is used to transfer different grating regions of the diffraction waveguide. These different grating regions have flat tops but different bottom thicknesses, resulting in different adhesive layer thicknesses (e.g., h4 / h5 / h6). Figure 3 (As shown in D1 / D2 / D3). In this way, the thickness of different regions of the diffractive waveguide changes. An excessively thick diffractive waveguide (such as the thickness of D1) increases the scattering of light within the diffractive waveguide compared to a thinner diffractive waveguide (such as the thickness of D3). Light energy is continuously lost, affecting the display effect of the diffractive waveguide.
[0037] Based on this, the present invention needs to prepare a silicon template for a diffractive waveguide with different grating heights and flush bottoms, so that the top of the grating in the soft template after transfer is flush and the bottom thickness is different. Thus, the grating height in the diffractive waveguide formed by the transfer of the soft template is different and the bottom is flush, thereby solving the problem of poor display effect caused by inconsistent bottom adhesive residue.
[0038] Furthermore, the present invention provides a method for fabricating a silicon template for a diffractive optical waveguide, comprising: forming a grating film layer on a silicon substrate, and performing a photolithography process on the grating film layer based on corresponding photolithography parameters to form a grating structure with different bottom flush heights; or, forming a template pattern film layer on a silicon substrate, forming corresponding grating materials between the pattern gaps of the template pattern film layer, and removing the template pattern film layer to form a grating structure with different bottom flush heights.
[0039] The above method can be used to form grating structures with silicon templates having different bottom heights and flush bottoms (such as...). Figure 4 As shown in the figure, the diffractive waveguide obtained through this silicon template ensures that the display effect of the diffractive waveguide is not affected by the difference in thickness when light propagates into the interior of the diffractive waveguide.
[0040] The method for fabricating a silicon template for a diffractive waveguide proposed in this invention will now be described with reference to the accompanying drawings.
[0041] Optionally, each grating film layer is formed on a silicon substrate, and a photolithography process is performed on the grating film layers based on corresponding photolithography parameters to form a grating structure with different bottom flush heights, including at least:
[0042] A first grating film layer of a first height is formed in a first region on a silicon substrate, and a photolithography process is performed on the first grating film layer to form a first grating; the first region is masked, and a second grating film layer of a second height is formed in a second region on a silicon substrate, and a photolithography process is performed on the second grating film layer to form a second grating.
[0043] The first height and the second height are different, the first region and the second region are different regions, the etching height of the first grating is the same as the first height, and the etching height of the second grating is the same as the second height.
[0044] Figure 5 This is a flowchart illustrating a method for fabricating a silicon template for a first diffractive optical waveguide according to an embodiment of the present invention. Figure 6 This is a schematic diagram illustrating the fabrication process of the silicon template for the first type of diffractive waveguide provided in this embodiment of the invention. (Refer to...) Figure 5 and Figure 6 The methods for fabricating silicon templates for diffractive waveguides include:
[0045] S101. Prepare a silicon substrate and form a first grating film layer of a first height in a first region on one side surface of the silicon substrate.
[0046] Exemplarily, the silicon substrate 10 can be one or more materials such as sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon. The first region 101 is a portion of one side surface of the silicon substrate 10. The position, shape, and size of the first region 101 can be set according to actual needs, and the first height can be set according to actual needs; this embodiment of the invention does not impose specific limitations on this. As an example, the first height can be 100nm-500nm. The method for forming the first grating film layer 11 includes physical vapor deposition, chemical vapor deposition, etc., and this embodiment of the invention does not impose limitations on this. The material of the first grating film layer 11 can be silicon dioxide, silicon nitride, hafnium oxide, silicon carbide, aluminum oxide, etc. Specifically, a metal shield with openings is installed on the silicon substrate 10. The openings of the metal shield correspond to the first region 101 of the silicon substrate 10. The first grating film layer 11 is formed by depositing through the openings in the first region 101 of the silicon substrate 10 using physical vapor deposition or chemical vapor deposition. Figure 6 (as shown in (a)).
[0047] S102. Perform photolithography on the first grating film layer to form the first grating;
[0048] Specifically, firstly, a first photoresist layer 12 is formed by homogenization on the first grating film layer 11. The photoresist type must match the mask type (i.e., a positive photoresist uses a positive photomask, and a negative photoresist uses a negative photomask). The homogenization thickness is 100nm-500nm, and the photoresist is baked at 90°C-120°C for 60S-120S (e.g., ...). Figure 6 (as shown in (b)).
[0049] Next, alignment exposure is performed on the silicon substrate 10 after photoresist homogenization, that is, the grating structure of the mask is transferred to the first photoresist 12 to form the first grating pattern layer.
[0050] Next, the exposed silicon substrate undergoes post-exposure baking, placed on a hot plate at 90°C-120°C for 60-120 seconds. It is then immersed in a 2.38% TMAH solution for 50-70 seconds for development. After development, the mask grating on the silicon substrate is completely transferred to the photoresist layer to form the first grating pattern, while the photoresist layer in the non-grating areas is left behind for protection after development (e.g., ...). Figure 6 (as shown in (c)).
[0051] Next, etching is performed using an ion beam etching or inductively coupled plasma etching machine to transfer the grating pattern transferred to the photoresist after the first exposure to the first grating film layer 11, stopping just at the silicon substrate 10 (e.g., ...). Figure 6 (d) is shown.
[0052] Then, the photoresist on the first grating 11 and the non-grating areas are removed to form the first grating 11 (e.g. Figure 6 (as shown in (e)).
[0053] S103. The first region is blocked, and a second grating film layer of second height is formed in the second region on the same side of the silicon substrate.
[0054] Before forming the second grating film layer 13, a metal baffle is used to protect the first region 101 and other regions on the silicon substrate 10, exposing the second region 102 on the silicon substrate 10. Specifically, the metal baffle also has a hole, the size of which corresponds to the second region 102 on the silicon substrate 10.
[0055] For example, a metal shield can be used to shield and protect the first region 101 and other regions, forming the second grating film layer 13 only in the second region 102 of the silicon substrate 10. The second region 102 is a portion of one side surface of the silicon substrate 10. The position, shape, and size of the second region 102 can be set according to actual needs, and the second height can be set according to actual needs. The first height is different from the second height, and this embodiment of the invention does not impose specific limitations on this. As an example, the second height can be 30nm-300nm. The method for forming the second grating film layer 13 includes physical vapor deposition, chemical vapor deposition, etc., and this embodiment of the invention does not impose limitations on this. Specifically, a metal shield with openings is installed on the silicon substrate 10. The openings of the metal shield correspond to the second region 102 of the silicon substrate 10. The second grating film layer 13 is formed by depositing through the openings in the second region 102 of the silicon substrate 10 using physical vapor deposition or chemical vapor deposition. Figure 6 (f) shown)
[0056] S104. Perform photolithography on the second grating film to form the second grating.
[0057] Specifically, firstly, a second photoresist layer 14 is formed by homogenization on the second grating film layer 13. The photoresist type must match the mask type (i.e., a positive photoresist uses a positive photomask, and a negative photoresist uses a negative photomask). The homogenization thickness is 100nm-500nm, and the photoresist is baked at 90°C-120°C for 60S-120S (e.g., ...). Figure 6 (g) is shown.
[0058] Secondly, alignment exposure is performed on the silicon substrate after photoresist homogenization, that is, the grating structure of the mask is transferred to the photoresist to form the second grating pattern layer.
[0059] Next, the exposed silicon substrate undergoes post-exposure baking, placed on a hot plate at 90°C-120°C for 60-120 seconds. It is then immersed in a 2.38% TMAH solution for 50-70 seconds for development. After development, the photomask grating on the silicon substrate is completely transferred to the photoresist layer to form the second grating pattern, while the photoresist layer in the non-grating areas is left behind for protection after development (e.g., ...). Figure 6 (as shown in (h)).
[0060] Next, etching is performed using an ion beam etching or inductively coupled plasma etching machine to transfer the grating pattern transferred to the photoresist after the second exposure to the second grating film layer 13, stopping just at the silicon layer (e.g., ...). Figure 6 (as shown in (i)).
[0061] Then, the photoresist on the grating pattern and in the non-grating areas is removed to form a second grating (such as...). Figure 6 (j) is shown.
[0062] In the above example, the first grating can be an inserted grating, and the second grating can be an exit grating. If a transition grating is to be formed, a third grating film layer is formed in a third region on the silicon substrate. The thickness of the third grating film layer can range from 30nm to 300nm. The third grating film layer is then photolithographically etched to form a third mask pattern. The first and second regions are then protected, and the third grating film layer is etched using the third mask pattern to form the third grating, which is the transition grating. It should be noted that the fabrication of the first, second, or third grating described above is merely an example. In practice, the required number of grating structures can be fabricated according to the above process as needed, and no limitation is made here. Furthermore, this scheme illustrates the idea of fabricating grating structures of the required grating height in different regions on the silicon substrate in a step-by-step manner. Specific implementation examples based on this idea should be included within this scheme.
[0063] In other embodiments, a first grating film layer of a first height can be formed in a first region on a silicon substrate, and the first region can be masked. A second grating film layer of a second height can be formed in a second region on the silicon substrate, and the second region can be masked. A photolithography process is then performed on the first grating film layer to form a first grating. The first region is then masked, and a photolithography process is then performed on the second grating film layer to form a second grating. Here, the first height and the second height are different, the first region and the second region are different regions, the etching height of the first grating is the same as the first height, and the etching height of the second grating is the same as the second height. Furthermore, by first performing the deposition process for forming the first grating film layer and the second grating film layer separately, and then performing the photolithography processes for the first and second grating film layers separately, the overlapping of different processes is avoided, thereby saving time and improving efficiency.
[0064] The technical solution provided by this invention divides the silicon substrate of the silicon template into a first region and a second region. A first grating is formed in the first region, and a second grating is formed in the second region after the first region is blocked. The first height of the first grating is different from the second height of the second grating. Since the photolithography process is performed in sections, a mask with the same photolithography pattern can be used in the same photolithography process, which simplifies the process and reduces costs. At the same time, by setting a grating structure with different bottom flush heights, the display effect of the diffracted waveguide will not be affected by the difference in thickness when light is transmitted to the inside of the diffracted waveguide, thereby improving the display performance of the diffracted waveguide.
[0065] Optionally, each grating film layer is formed on a silicon substrate, and a photolithography process is performed on the grating film layers based on corresponding photolithography parameters to form a grating structure with different bottom flush heights, including at least:
[0066] A highly uniform grating film layer is formed on a silicon substrate. The grating film layer is then subjected to photolithography to form a grating layer. Finally, the grating layer is subjected to a partitioned etching and thinning process to form a grating structure with different heights and flush bottoms.
[0067] Figure 7 This is a flowchart illustrating the fabrication method of a silicon template for a second diffractive waveguide according to an embodiment of the present invention. Figure 8 This is a schematic diagram illustrating the fabrication process of the silicon template for the second type of diffractive waveguide provided in this embodiment of the invention. (Refer to...) Figure 7 and Figure 8 Another preparation method includes:
[0068] S201. Prepare a silicon substrate and form a highly uniform grating film layer on one side of the silicon substrate surface.
[0069] The method of forming the grating film layer 21 can refer to steps S101 and S103 in the previous embodiment, and will not be repeated here (e.g. Figure 8 (a) is shown.
[0070] S202. Perform photolithography on the grating film to form the grating layer.
[0071] Specifically, firstly, a photoresist layer 22 is formed by homogenization on the grating film layer 21. The photoresist type must match the mask type (i.e., a positive photoresist uses a positive photomask, and a negative photoresist uses a negative photomask). The homogenization thickness is 100nm-500nm, and the photoresist is baked at 90°C-120°C for 60-120 seconds. Figure 8 (as shown in (b)).
[0072] Secondly, alignment and exposure are performed on the silicon substrate after photoresist coating, that is, the grating structure of the mask is transferred to the photoresist to form a grating pattern layer.
[0073] Next, the exposed silicon substrate undergoes post-exposure baking, placed on a hot plate at 90°C-120°C for 60-120 seconds. It is then immersed in a 2.38% TMAH solution for 50-70 seconds for development. After development, the mask grating is completely transferred to the photoresist layer on the silicon substrate to form the grating pattern (e.g., ...). Figure 8 (as shown in (c)).
[0074] Next, etching is performed using an ion beam etching or inductively coupled plasma etching machine to transfer the grating pattern, which was transferred to the photoresist after exposure, onto the grating film layer 21, stopping just at the silicon layer (e.g., ...). Figure 8 (d) is shown.
[0075] Then, the photoresist on the grating pattern is removed to form the grating layer (e.g. Figure 8 (as shown in (e)).
[0076] S203. Perform a partitioned etching and thinning process on the grating layer to form a grating structure with different heights and flush bottoms.
[0077] A photoresist layer 23 is formed on the grating layer (e.g., ...). Figure 8 (as shown in (f)), then, the photoresist layer in the area to be etched and thinned (exemplarily the first region 101) is overexposed and developed, which can expose the grating layer in the first region 101 (as shown in (f)). Figure 8 As shown in (g), the grating layer in the first region 101 is then etched and thinned (as shown in (g)). Figure 8 (as shown in (h)). Then the photoresist 23 is removed, leaving grating structures of different heights (as shown in (h)). Figure 8 (as shown in (i)).
[0078] In this embodiment, if other areas need to be etched and thinned, the same steps as in S203 can be used to etch and thin different areas to form a grating structure with the required height.
[0079] The technical solution provided by the embodiments of the present invention first forms a grating structure with a uniform height on the silicon substrate of the silicon template, and then forms gratings with different heights in different regions, which can improve the fabrication efficiency of silicon templates for diffractive waveguides.
[0080] Optionally, forming a template pattern film layer on a silicon substrate and forming corresponding grating material between the pattern gaps of the template pattern film layer, and removing the template pattern film layer to form a grating structure with different bottom flush heights, includes at least the following:
[0081] A first template pattern film layer is formed in a first region on a silicon substrate, and a first grating material is deposited in the pattern gaps of the template pattern film layer to form a first grating; a second template pattern film layer is formed in a second region on a silicon substrate, and a second grating material is deposited in the pattern gaps of the second template pattern film layer to form a second grating.
[0082] The height of the first grating is different from the height of the second grating. The height of the first grating is less than or equal to the height of the first template pattern film layer, and the height of the second grating is less than or equal to the height of the second template pattern film layer.
[0083] Figure 9 This is a flowchart illustrating the fabrication method of a silicon template for a third type of diffractive waveguide provided in this embodiment of the invention. Figure 10 This is a schematic diagram illustrating the fabrication process of a silicon template for a third type of diffractive waveguide according to an embodiment of the present invention. Figure 11 A schematic diagram illustrating the fabrication process of a silicon template for a third type of diffractive waveguide according to another embodiment of the present invention, referenced. Figures 9 to 11 In this embodiment, the template pattern film layer is a photoresist layer, and the preparation method includes:
[0084] S301. Prepare a silicon substrate and form a first photoresist layer of a first height in a first region on one side surface of the silicon substrate.
[0085] A silicon substrate is obtained, cleaned, and dried. Then, a layer of photoresist is deposited on the surface of the silicon substrate; in one embodiment, as shown... Figure 10 As shown in (a) and as Figure 11 As shown in (a), a silicon substrate 10 is fabricated, and a first photoresist layer 31 of a first height is formed in a first region 101 on one side surface of the silicon substrate 10. It should be noted that in this step, the second region needs to be masked. The masking method can be physical masking or masking using the first photoresist layer. Figure 10 This is an illustration of physical shielding (the first photoresist 31 is formed in the first region 101 by spraying or printing). Figure 11 This is an illustration of a photoresist layer masking example, where the first photoresist 31 is spin-coated onto the surface of a silicon substrate.
[0086] S302. Expose and develop the first photoresist layer to form the first template pattern film layer.
[0087] The photoresist layer on the silicon substrate is exposed and developed using a first grating structure to form a first photoresist pattern mask on the silicon substrate; in one embodiment, such as Figure 10 As shown in (b) and as Figure 11 As shown in (b), the first photoresist layer 31 is exposed to form the first template pattern film layer.
[0088] S303. Perform a dissolution and peeling process on the first template pattern film layer to deposit the first grating material in the pattern gaps of the first template pattern film layer, and the first grating material forms the first grating.
[0089] For example, the lift-off process is a metal removal process. It involves obtaining a patterned photoresist structure or metal mask on a substrate using photolithography, then evaporating the required metal along with the photoresist, and finally removing the metal from the photoresist film while removing the photoresist, leaving only the grating structure on the substrate. The first grating material is the same as the material used for the first grating itself, i.e., it is one of silicon dioxide, silicon nitride, silicon oxide, silicon carbide, hafnium oxide, or aluminum oxide. This can be set according to actual needs, and this embodiment of the invention does not impose specific limitations. The first grating material is deposited in the gaps between the patterns of the first template pattern film layer, and then the first template pattern film layer is removed to form the first grating on the surface of the silicon substrate 10. The height of the first grating is less than or equal to the height of the first template pattern film layer.
[0090] In one implementation, such as Figure 10 As shown in (c) and as Figure 11 As shown in (c), a dissolution and peeling process is performed on the first template pattern film layer to deposit the first grating material in the pattern gap of the first template pattern film layer, and the first grating material forms the first grating 32.
[0091] S304. The first region is shielded, and a second photoresist layer of a second height is formed in the second region on the same side of the silicon substrate.
[0092] In one implementation, such as Figure 10 As shown in (d) and as Figure 11 As shown in (d), the first region 101 is masked, and a second photoresist layer 33 of a second height is formed in the second region 102 on the same side of the silicon substrate. In this embodiment, the masking of the first region 101 can be achieved by physically masking it with a metal baffle, or by directly covering the first region 101 with the second photoresist layer. The present invention does not impose specific limitations on this. Figure 10 This diagram illustrates physical occlusion as an example. Figure 11 This diagram illustrates the use of photoresist layer masking as an example.
[0093] S305. Expose and develop the second photoresist layer to form the second template pattern film layer.
[0094] In one implementation, such as Figure 10 As shown in (e) and as Figure 11 As shown in (e), the second photoresist layer 33 is exposed and developed to form the second template pattern film layer.
[0095] S306. Perform a dissolution and peeling process on the second template pattern film layer to deposit a second grating material in the pattern gaps of the second template pattern film layer, and the second grating material forms a second grating.
[0096] For example, the second grating material is the same as the second grating material, that is, the second grating material is one of silicon dioxide, silicon nitride, silicon oxide, silicon carbide, hafnium oxide, or aluminum oxide. It can be set according to actual needs, and this embodiment of the invention does not impose specific limitations on it. The second grating material is deposited in the pattern gaps of the second template pattern film layer, and then the second template pattern film layer is removed to form a second grating 34 on the surface of the silicon substrate 10. The height of the first grating 32 is different from the height of the second grating 32, and the height of the second grating 32 is less than or equal to the height of the second template pattern film layer.
[0097] In one implementation, such as Figure 10 As shown in (f) and as Figure 11 As shown in (f), a dissolution and peeling process is performed on the second template pattern film layer to deposit a second grating material in the pattern gaps of the second template pattern film layer, thereby removing the second template pattern film layer as shown in (f). Figure 10 (g) as shown and as Figure 11 As shown in (g), the second grating material forms the second grating 34.
[0098] The technical solution provided by this invention divides the silicon substrate of the silicon template into a first region and a second region. A first grating is deposited in the first region, and a second grating is deposited in the second region after the first region is blocked. The first height of the first grating is different from the second height of the second grating. The process is simple and the cost is reduced. At the same time, by setting a grating structure with different bottom flush heights, the display effect of the diffractive waveguide will not be affected by the difference in thickness when light is transmitted to the inside of the diffractive waveguide, thereby improving the display performance of the diffractive waveguide.
[0099] Figure 12 This is a flowchart illustrating the fabrication method of the silicon template for the fourth diffractive waveguide provided in this embodiment of the invention. Figure 13 This is a schematic diagram illustrating the fabrication process of the silicon template for the fourth type of diffractive waveguide provided in this embodiment of the invention. (Refer to...) Figure 12 and Figure 13 In this embodiment, the template pattern film layer is a structural layer, and the preparation method includes:
[0100] S401. Prepare a silicon substrate and form a first structural layer film of a first height in a first region on one side surface of the silicon substrate.
[0101] For example, the structural layer is a film layer used to form a grating structure. As an example, the material of the structural layer is an adhesive or titanium dioxide that is insoluble in acetone or PGMEA (propylene glycol methyl ether acetate solvent).
[0102] In one implementation, such as Figure 13 As shown in (a), a silicon substrate 10 is prepared, and a first structural layer film 41 of a first height is formed in a first region 101 on one side surface of the silicon substrate 10 (the structural layer can be deposited on the silicon substrate by means of a metal baffle during the process).
[0103] S402, A first photoresist layer is formed on the surface of the first structural layer away from the silicon substrate.
[0104] For example, the first photoresist layer 42 is used to photolithographically etch the first structural layer film 41, so that the first structural layer film 41 forms a pattern for obtaining the first grating.
[0105] In one implementation, such as Figure 13 As shown in (b), a first photoresist layer 42 is formed on the surface of the first structural layer 41 away from the silicon substrate 10. The first photoresist 42 can be formed by spin coating or spray printing. Figure 13 It is formed by spin coating.
[0106] S403. Expose and develop the first photoresist layer.
[0107] For example, the first photoresist layer 42 is exposed, the exposed silicon template is baked, the first grating pattern on the mask is transferred to the first photoresist layer 42, and then the first photoresist layer 42 is developed to form a photolithographic pattern, such as... Figure 13 As shown in (c).
[0108] S404. The first structural layer film is etched to form the first template pattern film.
[0109] For example, etching is performed on the first structural layer film 41 to transfer the first grating pattern on the mask to the first structural layer film 41, forming a first template pattern film. Figure 13 As shown in (d).
[0110] S405. Perform a dissolution and peeling process on the first template pattern film layer to deposit the first grating material in the pattern gaps of the first template pattern film layer, and the first grating material forms the first grating.
[0111] In one implementation, such as Figure 13As shown in (e), a solvent stripping process is performed on the first template pattern film layer to deposit the first grating material in the pattern gap of the first template pattern film layer, and the first structural film layer 41 is removed (wherein, the solvent removed is different from the solvent removed from the photoresist), and the first grating material forms the first grating 43.
[0112] S406. The first region is shielded, and a second structural layer film of a second height is formed in the second region on the same side of the silicon substrate.
[0113] In one implementation, such as Figure 13 As shown in (f), the first region 101 is shielded, and a second structural layer film 44 of a second height is formed in the second region 102 on the same side of the silicon substrate 10. The shielding of the first region 101 can be a physical shielding of a metal sheet.
[0114] S407. A second photoresist layer is formed on the surface of the second structural layer away from the silicon substrate.
[0115] For example, the second photoresist layer 45 can be formed by spin coating. The second photoresist layer 45 is used to photolithographically shape the second structural layer film 44, so that the second structural layer film 44 forms a pattern for obtaining the second grating (e.g., Figure 13 (g) is shown.
[0116] S408. Expose and develop the second photoresist layer to form a photolithographic pattern, such as... Figure 13 As shown in (h).
[0117] S409. Etch the second structural layer to form the second template pattern layer.
[0118] For example, etching is performed on the second structural layer film 44 to transfer the second grating pattern on the mask to the second structural layer film 44, and the second photoresist layer 45 is removed to form the second template pattern film (e.g., Figure 13 (as shown in (i)).
[0119] S410. Perform a dissolution and peeling process on the second template pattern film layer to deposit a second grating material in the pattern gaps of the second template pattern film layer, and the second grating material forms a second grating.
[0120] In one implementation, such as Figure 13 As shown in (j), a dissolution and peeling process is performed on the second template pattern film layer to deposit a second grating material in the pattern gaps of the second template pattern film layer, thereby removing the second template pattern film layer 44 as shown. Figure 13 As shown in (k), the second grating material forms the second grating 46.
[0121] The technical solution provided in this invention divides the silicon substrate of a silicon template into a first region and a second region. A structural layer is first formed in both regions. Then, a grating film with a grating pattern is formed by photolithography on the structural layer using a photoresist layer. A first grating is deposited in the first region, and a second grating is deposited in the second region after the first region is masked. The first height of the first grating and the second height of the second grating are different. By setting the structural layer, the obtained grating structure is more stable, which can improve the display performance of the diffractive waveguide.
[0122] Optionally, forming a template pattern film layer on a silicon substrate and forming corresponding grating material between the pattern gaps of the template pattern film layer, and removing the template pattern film layer to form a grating structure with different bottom flush heights, includes at least the following:
[0123] A template pattern film layer of the same height is formed on a silicon substrate. The template pattern film layer includes different first regions and second regions. The second region is blocked. A first grating material of a first height is deposited in the pattern gaps of the first region to form a first grating. The first region is blocked. A second grating material of a second height is deposited in the pattern gaps of the second region to form a second grating.
[0124] The first height and the second height are different, and the higher of the first height and the second height is less than or equal to the height of the template graphic film layer.
[0125] Figure 14 This is a flowchart illustrating the fifth method for fabricating a silicon template for a diffractive optical waveguide according to an embodiment of the present invention. Figure 15 This is a schematic diagram illustrating the fabrication process of the silicon template for the fifth type of diffractive waveguide provided in this embodiment of the invention. (Refer to...) Figure 14 and Figure 15 In this embodiment, the template pattern film layer is a photoresist layer, and the preparation method includes:
[0126] S501. Prepare a silicon substrate and form a photoresist layer on one side of the silicon substrate surface.
[0127] A silicon substrate is obtained, cleaned, and dried. Then, a layer of photoresist is spin-coated onto the surface of the silicon substrate; in one embodiment, as shown... Figure 15 As shown in (a), a silicon substrate 10 is prepared, and a photoresist layer 51 is formed on one side surface of the silicon substrate.
[0128] S502, Expose and develop the photoresist layer to form a template pattern film layer. For example... Figure 15 As shown in (b).
[0129] S503, the second region is masked, and a first grating material is deposited in the pattern gap of the template pattern film layer in the first region, and the first grating material forms a first grating.
[0130] It should be noted that in this step, the second area needs to be masked, and the masking method is physical masking. Figure 15 This illustration uses physical occlusion as an example. In one implementation, as... Figure 15 As shown in (c), the first grating material is deposited in the pattern gaps of the template pattern film layer in the first region, and finally it can be as follows: Figure 15 As shown in (e), the photoresist layer is removed to form the first grating 52 from the first grating material.
[0131] S504. The first region is masked, and a second grating material is deposited in the pattern gap of the template pattern film layer in the second region, and the second grating material forms a second grating.
[0132] In one implementation, such as Figure 15 As shown in (d), the first region 101 is masked. In this embodiment, the masking of the first region 101 can be achieved by physical masking using a metal baffle. A second grating material is deposited in the pattern gaps of the template pattern film layer in the second region, and then the template pattern film layer is removed as shown in the diagram. Figure 15 As shown in (e), the second grating material forms the second grating 53.
[0133] The technical solution provided by the embodiments of the present invention divides the silicon substrate of the silicon template into a first region and a second region. First, a template pattern film layer is formed in the first region and the second region. Then, a first grating is deposited in the first region. After the first region is blocked, a second grating is deposited in the second region, which can improve the fabrication efficiency of the diffractive waveguide.
[0134] Figure 16 This is a flowchart illustrating the sixth method for fabricating a silicon template for a diffractive optical waveguide according to an embodiment of the present invention. Figure 17 This is a schematic diagram illustrating the fabrication process of the silicon template for the sixth type of diffractive waveguide provided in this embodiment of the invention. (Refer to...) Figure 16 and Figure 17 In this embodiment, the template pattern film layer is a structural layer, and the preparation method includes:
[0135] S601. Prepare a silicon substrate and form a structural layer film on one side of the silicon substrate surface.
[0136] For example, the structural layer membrane 61 includes a first structural layer membrane in a first region 101 and a second structural layer membrane in a second region 102.
[0137] In one implementation, such as Figure 17 As shown in (a), a silicon substrate 10 is prepared, and a structural layer film 61 is formed on one side surface of the silicon substrate 10.
[0138] S602. A photoresist layer is formed on the surface of the structural layer film away from the silicon substrate.
[0139] For example, the photoresist layer 62 includes a first photoresist layer in a first region 101 and a second photoresist layer in a second region 102. The photoresist layer 62 is used to photolithographically etch the structural layer film 61, so that the structural layer film 61 forms patterns for obtaining the first grating and the second grating.
[0140] In one implementation, such as Figure 17 As shown in (b), a photoresist layer 62 is formed by spin coating on the side of the structural layer 61 away from the silicon substrate 10.
[0141] S603. Expose and develop the photoresist layer, and etch the structural layer to form a template pattern film.
[0142] For example, the photoresist layer is exposed, the exposed silicon template is baked, and after development, the grating pattern on the photomask is transferred to the photoresist layer. Figure 17 As shown in (c). Then, the structural layer film is etched to transfer the grating pattern from the mask to the structural layer film. After removing the photoresist, a template pattern film is formed, as shown in (c). Figure 17 As shown in (d).
[0143] S604. The second region is blocked, and a first grating material is deposited in the pattern gap of the template pattern film layer in the first region, and the first grating material forms a first grating.
[0144] In one implementation, such as Figure 17 As shown in (e), the second region 102 is occluded, wherein the occlusion method can be physical occlusion. A first grating material is deposited in the pattern gaps of the template pattern film layer in the first region 101, as shown in... Figure 17 After the structural layer is removed as shown in (g), the first grating material forms the first grating 63.
[0145] S605. The first region is masked, and a second grating material is deposited in the pattern gap of the template pattern film layer in the second region, and the second grating material forms a second grating.
[0146] In one implementation, such as Figure 17 As shown in (f), a second grating material is deposited in the pattern gaps of the template pattern film in the second region 102, and the template pattern film is removed as shown in (f). Figure 17 As shown in (g), the second grating material forms the second grating 64.
[0147] The technical solution provided by this invention involves first forming a structural layer and a photoresist layer on one side of the silicon substrate of a silicon template. The structural layer is divided into a first region and a second region. The second region is shielded while a first grating is deposited in the first region. The first region is shielded while a second grating is deposited in the second region. By setting the structural layer, the obtained grating structure is more stable, improving the display performance of the diffractive waveguide. At the same time, the same process steps are set together to improve the fabrication efficiency of the diffractive waveguide.
[0148] Optionally, before forming the template patterned film layer on the silicon substrate, the process includes:
[0149] A seed layer is formed on a silicon substrate, and the seed layer is made of a conductive material;
[0150] Forming a template pattern film layer on a silicon substrate, and forming corresponding grating materials between the pattern gaps of the template pattern film layer, and removing the template pattern film layer to form a grating structure with different bottom flush heights, includes at least the following:
[0151] A first template pattern film is formed in a first region of the seed layer, and a first grating material is electroplated or electroformed in the pattern gaps of the first template pattern film to form a first grating; a second template pattern film is formed in a second region of the seed layer, and a second grating material is electroplated or electroformed in the pattern gaps of the second template pattern film to form a second grating.
[0152] The height of the first grating is different from the height of the second grating.
[0153] Figure 18 The flowchart illustrates the seventh method for fabricating a silicon template for a diffractive optical waveguide according to an embodiment of the present invention. Figure 19 This is a schematic diagram illustrating the fabrication process of the silicon template for the seventh type of diffractive waveguide provided in this embodiment of the invention. (Refer to...) Figure 18 and 19 In this embodiment, the template pattern film layer is a photoresist layer, and the preparation method includes:
[0154] S701. Prepare a silicon substrate and form a seed layer on one side of the silicon substrate surface.
[0155] For example, the seed layer is made of a conductive material, but this embodiment of the invention does not impose specific limitations on it.
[0156] In one implementation, such as Figure 19 As shown in (a), a silicon substrate 10 is prepared, and a seed layer 71 is formed on one side surface of the silicon substrate 10.
[0157] S702, A first photoresist layer of a first height is formed in a first region on the side surface of the seed layer away from the silicon substrate.
[0158] In one implementation, such as Figure 19 As shown in (b), a first photoresist layer 72 of a first height is formed in a first region 101 on the surface of the seed layer 71 away from the silicon substrate 10. The first photoresist layer 72 can be formed by spin coating.
[0159] S703. Expose and develop the first photoresist layer to form the first template pattern film layer.
[0160] In one implementation, such as Figure 19 As shown in (c), the first photoresist layer 72 is exposed and developed to form the first template pattern film layer.
[0161] S704. The first template pattern film layer is subjected to electroplating or electroforming process, and the first grating material is electroplated or electroformed in the pattern gap of the first template pattern film layer, and the first grating material forms the first grating.
[0162] In one implementation, such as Figure 19 As shown in (d), the first template pattern film layer is subjected to electroplating or electroforming process, the first grating material is electroplated or electroformed in the pattern gap of the first template pattern film layer, and after the first photoresist layer is removed, the first grating material forms the first grating 73.
[0163] S705, The first region is shielded, and a second photoresist layer of a second height is formed in the second region on the same side of the silicon substrate.
[0164] In one implementation, such as Figure 19 As shown in (e), the first region 101 is masked, and a second photoresist layer 74 of a second height is formed in the second region 102 on the same side of the silicon substrate 10. The second photoresist layer 74 can be formed by spin coating.
[0165] S706. Expose and develop the second photoresist layer to form the second template pattern film layer.
[0166] In one implementation, such as Figure 19 As shown in (f), the second photoresist layer 74 is exposed and developed to form the second template pattern film layer.
[0167] S707. The second template pattern film layer is subjected to electroplating or electroforming process, and the second grating material is electroplated or electroformed in the pattern gap of the second template pattern film layer, and the second grating material forms the second grating.
[0168] In one implementation, such as Figure 19 As shown in (g), the second template pattern film layer is subjected to electroplating or electroforming processes. A second grating material is electroplated or electroformed into the pattern gaps of the second template pattern film layer. The second template pattern film layer is then removed as shown in (g). Figure 19 As shown in (h), the second grating material forms the second grating 75.
[0169] The technical solution provided by the embodiments of the present invention forms a seed layer on the surface of a silicon substrate, divides the silicon substrate of the silicon template into a first region and a second region, forms a first grating by electroplating or electroforming in the first region, and forms a second grating by electroplating or electroforming in the second region after the first region is blocked. The grating structure is formed by electroplating or electroforming process, thereby improving the display performance of the diffractive waveguide.
[0170] Figure 20 This is a flowchart illustrating the method for fabricating a silicon template for an eighth diffractive waveguide according to an embodiment of the present invention. Figure 21 This is a schematic diagram illustrating the fabrication process of the silicon template for the eighth type of diffractive waveguide provided in this embodiment of the invention. (Refer to...) Figure 20 and Figure 21 Another preparation method includes:
[0171] S801. Prepare a silicon substrate and form a seed layer on one side of the silicon substrate surface.
[0172] In one implementation, such as Figure 21 As shown in (a), a silicon substrate 10 is prepared, and a seed layer 81 is formed on one side surface of the silicon substrate 10.
[0173] S802, A first structural layer film of a first height is formed in a first region on the side surface of the seed layer away from the silicon substrate.
[0174] In one implementation, such as Figure 21 As shown in (b), a first structural layer film 82 of a first height is formed in a first region 101 on the side surface of the seed layer 81 away from the silicon substrate 10.
[0175] S803, A first photoresist layer is formed on the surface of the first structural layer away from the silicon substrate.
[0176] For example, the first photoresist layer 83 is used to photolithographically form the first structural layer film 82, so that the first structural layer film 82 forms a pattern for obtaining the first grating 84.
[0177] In one implementation, such as Figure 21 As shown in (c), a first photoresist layer 83 is formed on the surface of the first structural layer film 82 away from the silicon substrate 10.
[0178] S804. Expose and develop the first photoresist layer.
[0179] For example, the first photoresist layer 83 is exposed, the exposed silicon template is baked, and then developed to transfer the first grating pattern on the mask to the first photoresist layer 83 (e.g., ...). Figure 21(d) is shown.
[0180] S805. The first structural layer film is etched to form the first template pattern film.
[0181] In one implementation, such as Figure 21 As shown in (e), the first structural layer film 82 is etched to form the first template pattern film.
[0182] S806. The first template pattern film layer is subjected to electroplating or electroforming process, and the first grating material is electroplated or electroformed in the pattern gap of the first template pattern film layer, and the first grating material forms the first grating.
[0183] In one implementation, such as Figure 21 As shown in (f), the first template pattern film layer is subjected to electroplating or electroforming process, the first grating material is electroplated or electroformed in the pattern gap of the first template pattern film layer, the first photoresist layer 83 and the first template pattern film layer are removed, and the first grating material forms the first grating 84.
[0184] S807. The first region is shielded, and a second structural layer film of a second height is formed in the second region on the same side of the silicon substrate.
[0185] In one implementation, such as Figure 21 As shown in (g), the first region 101 is shielded, and a second structural layer film 85 of a second height is formed in the second region 102 on the same side of the silicon substrate 10. In this embodiment, the shielding of the first region 101 can be achieved by physically shielding it with a metal baffle.
[0186] S808. A second photoresist layer is formed on the surface of the second structural layer away from the silicon substrate.
[0187] In one implementation, such as Figure 21 As shown in (h), a second photoresist layer 86 is formed by spin coating on the side of the second structural layer film 85 away from the silicon substrate 10.
[0188] S809. Expose and develop the second photoresist layer.
[0189] In one implementation, such as Figure 21 As shown in (i), the second photoresist layer 86 is exposed and developed to form an etched pattern.
[0190] S810. The second structural layer film is etched to form the second template pattern film.
[0191] For example, etching is performed on the second structural layer film 85 to transfer the second grating pattern on the mask to the second structural layer film 86, forming a second template pattern film (such as...). Figure 21 (j) is shown.
[0192] S811. The second template pattern film layer is subjected to electroplating or electroforming process, and the second grating material is electroplated or electroformed in the pattern gap of the second template pattern film layer, and the second grating material forms the second grating.
[0193] In one implementation, such as Figure 21 As shown in (k), the second template pattern film layer is subjected to electroplating or electroforming processes. A second grating material is electroplated or electroformed into the gaps between the patterns in the second template pattern film layer. The second photoresist layer is removed, and then the second template pattern film layer is removed as shown in (k). Figure 21 As shown in (l), the second grating material forms the second grating 87.
[0194] The technical solution provided by the embodiments of the present invention forms a seed layer on the surface of a silicon substrate, divides the silicon substrate of the silicon template into a first region and a second region, forms a structural layer film in the first region and the second region, and then performs photolithography on the structural layer film to form a grating film with a grating pattern through a photoresist layer. A first grating is formed by electroplating or electroforming in the first region, and a second grating is formed by electroplating or electroforming in the second region after the first region is blocked. The grating structure is formed by electroplating or electroforming process, thereby improving the display performance of the diffractive waveguide.
[0195] Optionally, before forming the template patterned film layer on the silicon substrate, the process includes:
[0196] A seed layer is formed on a silicon substrate, and the seed layer is made of a conductive material;
[0197] Forming a template pattern film layer on a silicon substrate, and forming corresponding grating materials between the pattern gaps of the template pattern film layer, and removing the template pattern film layer to form a grating structure with different bottom flush heights, includes at least the following:
[0198] A template pattern film layer of the same height is formed on the seed layer. The template pattern film layer includes different first regions and second regions. The second region is blocked. A first grating material of a first height is electroplated or electroformed in the pattern gaps of the first region. The first grating material forms a first grating. The first region is blocked. A second grating material of a second height is electroplated or electroformed in the pattern gaps of the second region. The second grating material forms a second grating.
[0199] The first height and the second height are different, and the template graphic film layer is a structural graphic film layer.
[0200] Figure 22 This is a flowchart illustrating the ninth method for fabricating a silicon template for a diffractive optical waveguide according to an embodiment of the present invention. Figure 23 This is a schematic diagram illustrating the fabrication process of the silicon template for the ninth type of diffractive waveguide provided in this embodiment of the invention. (Refer to...) Figure 22and Figure 23 Another preparation method includes:
[0201] S111. Prepare a silicon substrate and form a seed layer on one side of the silicon substrate surface.
[0202] In one implementation, such as Figure 23 As shown in (a), a silicon substrate 10 is prepared, and a seed layer 111 is formed on one side surface of the silicon substrate 10.
[0203] S112. A structural layer film is formed on the surface of the seed layer away from the silicon substrate.
[0204] In one implementation, such as Figure 23 As shown in (b), a structural layer film 112 is formed on the surface of the seed layer 19 away from the silicon substrate 10.
[0205] S113. A photoresist layer is formed on the side of the structural layer away from the silicon substrate.
[0206] In one implementation, such as Figure 23 As shown in (c), a photoresist layer 113 is formed on the side of the structural layer film away from the silicon substrate 10.
[0207] S114. Expose and develop the photoresist layer (e.g.) Figure 23 As shown in (d), the structural layer film is etched to form a template pattern film, such as Figure 23 As shown in (e).
[0208] S115. Spin-coat photoresist onto the template pattern film layer, and overexpose and develop the first region to form the first template pattern film layer, such as... Figure 23 As shown in (f).
[0209] S116. The template pattern film layer in the first region is subjected to electroplating or electroforming process, and the first grating material is electroplated or electroformed in the pattern gap of the template pattern film layer in the first region, and the first grating material forms the first grating.
[0210] In one implementation, such as Figure 23 As shown in (g), the template pattern film layer in the first region is subjected to electroplating or electroforming process, and the first grating material is electroplated or electroformed in the pattern gap of the first template pattern film layer. After removing the structural layer, the first grating material is formed to form the first grating 114.
[0211] S117. The first region is masked, and the template pattern film layer in the second region is electroplated or electroformed. The second grating material is electroplated or electroformed in the pattern gap of the second template pattern film layer, and the second grating material forms the second grating.
[0212] In one embodiment, the photoresist in step S115 is removed, and the photoresist is spin-coated again. The photoresist layer in the second region is then overexposed and developed to form a template pattern film layer in the second region, such as... Figure 23 As shown in (h), the template pattern film layer in the second region is subjected to electroplating or electroforming processes, and a second grating material is electroplated or electroformed in the pattern gaps of the second template pattern film layer. Figure 23 As shown in (i), the second template pattern film layer and the photoresist in the first region are removed to form the first grating 114 and the second grating 115 as shown. Figure 23 As shown in (j).
[0213] The technical solution provided by this invention involves first forming a structural layer and a photoresist layer on one side of the silicon substrate of a silicon template. The structural layer is divided into a first region and a second region. Within the first and second regions, the structural layer is photolithographically lithographically formed using the photoresist layer to create a grating layer with a grating pattern. The grating is then formed by electroplating or electroforming within the first and second regions, respectively. By setting the structural layer, the obtained grating structure is more stable, improving the display performance of the diffractive waveguide. Furthermore, by performing the same process steps together, the fabrication efficiency of the diffractive waveguide is improved.
[0214] 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 fabricating a silicon template for a diffractive optical waveguide, characterized in that, include: A grating film layer is formed on a silicon substrate, and a photolithography process is performed on the grating film layer based on corresponding photolithography parameters to form a grating structure with different heights and flush bottoms. The grating structure includes a grating structure in a first region and a grating structure in a second region; wherein, the bottom flush height of the grating structure in the first region is the same, the bottom flush height of the grating structure in the second region is the same, and the bottom flush height of the grating structure in the first region and the second region are different. Wherein, the first region corresponds to at least one region of the coupling-in grating region, the transition grating region, and the coupling-out grating region of the diffractive waveguide, and the second region corresponds to at least one region of the coupling-in grating region, the transition grating region, and the coupling-out grating region of the diffractive waveguide; the first region and the second region correspond to different regions of the diffractive waveguide; The process of forming a grating film layer on a silicon substrate and performing a photolithography process on the grating film layer based on corresponding photolithography parameters to form a grating structure with different bottom flush heights includes at least the following: When performing photolithography on the grating film layer corresponding to one of the first region and the second region, or when etching and thinning the grating layer corresponding to one of the first region and the second region, a photoresist layer is used to shield other regions besides the one region.
2. The method for fabricating a silicon template for a diffractive optical waveguide according to claim 1, characterized in that, The process of forming a grating film layer on a silicon substrate and performing a photolithography process on the grating film layer based on corresponding photolithography parameters to form a grating structure with different bottom flush heights includes at least the following: A first grating film layer of a first height is formed in a first region on the silicon substrate, and a photolithography process is performed on the first grating film layer to form a first grating; a photoresist layer is used to mask the first region, and a second grating film layer of a second height is formed in a second region on the silicon substrate, and a photolithography process is performed on the second grating film layer to form a second grating. Wherein, the first height and the second height are different, the etching height of the first grating is the same as the first height, and the etching height of the second grating is the same as the second height.
3. The method for fabricating a silicon template for a diffractive optical waveguide according to claim 1, characterized in that, The process of forming a grating film layer on a silicon substrate and performing a photolithography process on the grating film layer based on corresponding photolithography parameters to form a grating structure with different bottom flush heights includes at least the following: A grating film layer with a uniform height is formed on the silicon substrate. The grating film layer is subjected to photolithography to form a grating layer. When etching and thinning the grating layer on the first region or the second region, a photoresist layer is used to block other regions outside the area to be etched and thinned, forming a grating structure with different heights and flush bottoms.
4. The method for preparing the silicon template for the diffractive waveguide according to claim 2, characterized in that, The first grating is made of one of silicon dioxide, silicon nitride, silicon oxide, silicon carbide, hafnium oxide, or aluminum oxide; the second grating is made of one of silicon dioxide, silicon nitride, silicon oxide, silicon carbide, hafnium oxide, or aluminum oxide; wherein the material of the first grating is the same as or different from the material of the second grating.
Citation Information
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