Patterned baffles, depth control methods for micro-nano optical structures, and diffraction gratings

Abstract

The present invention provides a patterned baffle, a method for controlling the depth of a micro-nano optical structure, and a diffraction grating. The patterned baffle is used to modulate a micro-nano optical structure with a continuously and gradually varying depth. The baffle comprises: a first sector-shaped substrate and a second sector-shaped substrate, wherein the center of the first sector-shaped substrate coincides with that of the second sector-shaped substrate and their edges are arranged adjacently; the first sector-shaped substrate is composed of at least one sector-shaped segment; the second sector-shaped substrate is composed of at least two sector-shaped segments of different radii, which are concentrically arranged and adjacent to each other; the radius of any sector-shaped segment in the first sector-shaped substrate is not equal to the radius of any sector-shaped segment in the second sector-shaped substrate. By setting different radii for different sector-shaped segments, the etching accuracy of the nanoscale optical structure is improved, and in particular, precise modulation of continuously and gradually varying depth is achieved, thereby preparing a grating structure region with multiple different depths, wherein the grating structure depth within each grating structure region is the same.

Description

Technical Field

[0001] The present invention relates to the technical field of ion beam etching, and in particular to a patterned baffle, a depth control method for a micro-nano optical structure, and a diffraction grating. Background Art

[0002] In semiconductor manufacturing, ion beam etching, as a high-precision etching process, is widely used in a number of key industries, including semiconductor manufacturing, microelectromechanical systems (MEMS), photonic devices, and nanomaterial processing. However, despite significant achievements in many areas, ion beam etching technology still faces some key technical challenges that need to be addressed.

[0003] Existing ion beam etching equipment uses a baffle structure to partially block the ion beam and controls the movement of the baffle to control the etching depth. For those skilled in the art, controlling the movement of the baffle during the etching process to achieve modulation of the target depth is very difficult, especially for diffraction grating structures with grating sizes ranging from tens of nanometers to one or two hundred nanometers, which makes it difficult to meet the etching accuracy requirements.

[0004] Therefore, for those skilled in the art, how to improve the etching accuracy of nano-scale optical structures when the depth varies is an urgent problem to be solved. Summary of the Invention

[0005] The present invention provides a patterned baffle, a depth control method for a micro-nano optical structure, and a diffraction grating, which improve the etching accuracy of the nano-level optical structure when the depth changes.

[0006] A patterned baffle for preparing a micro-nano optical structure with depth variation, the patterned baffle comprising: a first sector-shaped substrate and a second sector-shaped substrate, wherein the center of the first sector-shaped substrate coincides with that of the second sector-shaped substrate and the edges are arranged adjacently; the first sector-shaped substrate comprises at least one basic sector; the second sector-shaped substrate comprises at least one extended sector; the radius of the extended sector is smaller than the radius of the basic sector, and when there is more than one extended sector, the extended sectors are concentric, arranged adjacently at the edges, and have different radii.

[0007] Practically, the micro-nano optical structure is a diffraction grating structure in a diffraction optical waveguide.

[0008] In practice, the depth change includes at least one of a depth gradient change and a depth continuous change.

[0009] Practically, when the sum of the central angles of the first sector-shaped substrate and the second sector-shaped substrate is 360°, the sum of the number of extended sectors in the second sector-shaped substrate is equal to the number of depths of different sizes of the micro-nano optical structure.

[0010] Practically, the radius of the extended sector in the second sector-shaped substrate increases or decreases sequentially along the same direction; the opening ratio between the first sector-shaped substrate and the second sector-shaped substrate changes with the radius of the extended sector in the second sector-shaped substrate.

[0011] A patterned baffle is used to prepare a micro-nano optical structure with depth variation. The patterned baffle has a special shape, which is the substrate shape after the area of ​​the same shape as the fan-shaped substrate second is removed concentrically in the fan-shaped substrate first; the fan-shaped substrate first includes at least one basic fan-shaped; the fan-shaped substrate second includes at least one extended fan-shaped; the radius of the extended fan-shaped is smaller than the radius of the basic fan-shaped, and when there is more than one extended fan-shaped, each extended fan-shaped is concentric, has adjacent edges, and has different radii.

[0012] A method for controlling the depth of a micro-nano optical structure, the method comprising:

[0013] Providing a substrate and the patterned baffle described in any one of the above items;

[0014] forming a patterned mask layer on the substrate; wherein the patterned area of ​​the patterned mask layer is a target area where the micro-nano optical structure is to be formed, and the position of the patterned area is selected so that the target depth variation direction of the micro-nano optical structure is consistent with the radial direction of the substrate;

[0015] The patterned baffle is coaxially arranged with the substrate, the patterned baffle or the substrate is rotated and the substrate is etched so that the substrate is partially shielded by the patterned baffle during etching, thereby obtaining micro-nano optical structures with several different depths on the substrate.

[0016] A method for controlling the depth of a micro-nano optical structure, the method comprising:

[0017] Providing a substrate and the patterned baffle described in any one of the above items;

[0018] forming a patterned sacrificial layer on the substrate, wherein a window region of the patterned sacrificial layer is a target region where the micro-nano optical structure is to be formed, and a position of the window region is selected so that a target depth variation direction of the micro-nano optical structure is consistent with a radial direction of the substrate;

[0019] The patterned baffle is coaxially arranged with the substrate, the patterned baffle or the substrate is rotated, and the substrate is etched so that the substrate is partially shielded by the patterned baffle during etching, thereby forming a plurality of steps of different depths in the window area;

[0020] After removing the remaining patterned sacrificial layer on the substrate, a patterned mask layer is formed on the substrate, wherein a patterned area of ​​the patterned mask layer is consistent with the window area;

[0021] The patterned baffle is coaxially arranged with the substrate, the patterned baffle or the substrate is rotated and the substrate is etched so that the substrate is partially shielded by the patterned baffle during etching, thereby obtaining micro-nano optical structures with several different depths on the substrate.

[0022] At the same time, the present application provides a diffraction grating, which is obtained by etching based on the depth control method described in the above embodiment.

[0023] In the present application, a specially structured graphical baffle is provided, comprising a concentrically arranged basic sector and an extended sector. The radius of the extended sector is smaller than that of the basic sector, and when there are more than one extended sector, the radii are different. This allows for the formation of multiple regions with different etching window sizes, each with a different aperture ratio, to form etched structure regions with varying depths, thereby obtaining grating structures that meet different diffraction efficiency requirements. The design of sector segments with varying radii improves the etching accuracy of nanoscale optical structures, particularly for etching regions of varying depths, achieving precise modulation of depth variation. Compared to existing technologies, this method can modulate the etching process to obtain a grating structure with varying depths, or even a grating structure with continuously varying depths. This method offers outstanding substantive features and significant advancements for those skilled in the art.

[0024] In another embodiment, the patterned baffle has a shape obtained by concentrically removing at least one extended sector-shaped area from the basic sector-shaped area; to form an etched structure area with varying depths, so that the patterned baffle can be used to obtain a grating structure that meets different diffraction efficiency requirements, i.e., different depth requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic diagram of a sector-shaped substrate 1 of a patterned baffle provided by the present invention;

[0027] Figure 2 A schematic diagram of a second sector-shaped substrate of a patterned baffle provided by the present invention;

[0028] Figure 3A schematic structural diagram of a graphic baffle provided by the present invention;

[0029] Figure 4 A schematic diagram of a patterned baffle etching substrate provided by the present invention Figure 1 ;

[0030] Figure 5 A schematic structural diagram of another patterned baffle provided by the present invention;

[0031] Figure 6 A schematic diagram of the etching structure during the etching process of a depth control method provided by the present invention;

[0032] Figure 7 A schematic diagram of the etching structure during the etching process of a depth control method provided by the present invention;

[0033] Figure 8 A schematic diagram of a patterned baffle etching substrate provided by the present invention Figure 2 ;

[0034] Figure 9 A schematic diagram showing the comparison between the patterned baffle and the substrate provided by the present invention. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0036] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0037] like Figures 1 and 2As shown, the present invention provides a patterned baffle for preparing a micro-nano optical structure with depth variation, the patterned baffle comprises: a sector-shaped substrate 10 and a sector-shaped substrate 20, the center of the sector-shaped substrate 10 and the center of the sector-shaped substrate 20 coincide with each other and their edges are adjacent to each other, as shown in FIG. Figure 3 As shown; the fan-shaped substrate 10 includes at least one basic fan-shaped; the fan-shaped substrate 20 includes at least one extended fan-shaped; it can be seen that the radius of the extended fan-shaped is smaller than the radius of the basic fan-shaped, and when there is more than one extended fan-shaped, the extended fans are concentric and adjacent to each other at the edges and have different radii.

[0038] In detail, such as Figure 1 As shown, the sector substrate 10 includes a basic sector with a radius r a , and has a central angle α. Figure 2 As shown in the left and middle figures, the sector substrate 20 includes four extended sectors with radii of r b1 、r b2 、r b3 、r b4 And they are different, with a central angle β. Figure 2 As shown in the right figure, the sector-shaped substrate 20 can also include more extended sectors with a larger central angle.

[0039] The present invention limits the sector segments with different radii in the sector-shaped substrate 1 and the sector-shaped substrate 2 to achieve etching modulation of different depths, thereby obtaining required structural areas of different depths.

[0040] Further, in detail, Figure 3 As shown, the radius r of the basic sector in the sector substrate 10 is a The radius of the extended sector is greater than that of any one of the sector-shaped substrates 20, so that at least a region greater than 3 depths is formed during etching. Figure 2 and Figure 3 As shown, Figure 2 The middle figure shows four extended sectors with different radius sizes arranged concentrically adjacently. When the center of the sector substrate 10 coincides with that of the sector substrate 20 and their edges are arranged adjacently, due to the radius r of the sector substrate 10, a is greater than the radius of any extended sector in the sector substrate 20, i.e. r a >r b1 , r a >r b2 , r a >r b3 , r a >r b4Therefore, the patterned baffle includes at least five sector segments with different radii, and when θ is not zero, five regions with different depths are formed during etching; by limiting the radius of different sector segments, depth modulation of different regions can be achieved.

[0041] certainly, Figure 2 、 Figure 3 Only a structural area including five different depths formed by five sector segments of different radius sizes is shown; in other embodiments, the number of sector segments of different radius sizes can be limited according to specific etching requirements, such as 3, 4, 6, etc. In this regard, based on the basic concept of the present invention, the present invention does not impose any specific limitation on the number of sector segments.

[0042] exist Figure 2 In the embodiment, the sector substrate 20 includes four extended sectors with different radii, that is, it includes four sector segments with different radii, such as r b1 、r b2 、r b3 、r b4 , an embodiment is shown in the figure, namely r b1 <r b2 <r b3 <r b4 ; Of course, in different embodiments, r b1 、r b2 、r b3 、r b4 The size of r can be different, that is, b1 、r b2 、r b3 、r b4 There is no limitation on the size relationship between them, and the structure of the patterned baffle is formed according to different etching requirements.

[0043] As an embodiment b1 Not equal to r b2 , or r b1 Equal to r b3 ; or another embodiment r b3 Not equal to r b4 , or r b1 Equal to r b4 , and so on. There are many different radius sizes, which are determined based on the different depth requirements of different areas during etching. It can be known that each radius corresponds to an etching depth. The larger the area of ​​the sector at this radius, the larger the blocked etching area, and the smaller the depth of the etching area formed.

[0044] For example, in a diffraction waveguide structure, the grating structure of the diffraction waveguide includes at least three grating regions, and the depths of different grating regions are different. That is, the radius and area of ​​the fan-shaped segments at different positions in the corresponding patterned baffle can be determined according to the depth requirements of different regions, thereby achieving the purpose of etching at different depths.

[0045] In this application, depth variation includes at least one of gradient depth variation and continuous depth variation. It is understood that the definition of continuous depth variation here means that the height difference between adjacent depth regions is controlled within a certain range, such as less than 5%, 10%, etc. Those skilled in the art may adjust the height difference based on different optical performance requirements, and this invention does not impose specific numerical limitations on this. However, the depth within the same depth region is the same.

[0046] Furthermore, when the height difference between adjacent regions of different depths exceeds a certain range, such as approximately 5%, 10%, etc., it is considered a depth gradient change.

[0047] The number of depth gradient changes or depth continuous changes within each grating region is less than or equal to the number of extended sectors in the patterned baffle.

[0048] Further, combined Figure 3 and Figure 4 It can be seen that when the sum of the central angles of the first and second sector-shaped substrates is less than 360°, that is, α+β<360° and θ≠0, the sum of the number of extended sectors in the second sector-shaped substrate is equal to the number of depths of different sizes of the micro-nano optical structure plus 1. When the sum of the central angles of the first and second sector-shaped substrates is 360°, that is, α+β=360°, the sum of the number of extended sectors in the second sector-shaped substrate is equal to the number of depths of different sizes of the micro-nano optical structure.

[0049] Of course, combined Figure 3 , the radius of the extended sector in the sector substrate 2 increases or decreases in the same direction. That is, the radius of the sector segments included in the sector substrate 2 changes monotonically in the same direction, such as Figure 3 In the clockwise direction, the radius of each sector increases successively; or from another angle, such as along Figure 3 In the counterclockwise direction, the radius of each sector decreases successively.

[0050] Indicative, combined Figure 3 In one embodiment, the radii of different sectors are limited to determine the etching depths at different locations, as shown in the following table:

[0051]

[0052] The aperture ratio refers to the ratio of the opening size enclosed by the first sector substrate 10 and the second sector substrate 20, that is, the size of the opening gap. Figure 3 As shown in FIG, the opening angle θ formed by the first sector-shaped substrate 10 and the second sector-shaped substrate 20 is θ=360°-α-β, and the opening ratio = θ / 360°×100%.

[0053] To explain in more detail, if the straight line based on the radius of the arc segment of the fan-shaped substrate 10 is used as a reference, the angle between the two straight lines corresponding to the fan segment of the adjacent fan-shaped substrate 20 is the opening size, and the opening ratio refers to the proportion of the opening size relative to the entire area 360°.

[0054] Based on the above embodiment, it can be known that the opening ratio between the first sector substrate and the second sector substrate varies with the radius of the sector segment in the second sector substrate. Figure 3 , it is limited that the aperture ratio enclosed by a certain sector segment in the sector-shaped substrate 10 and the sector-shaped substrate 2 20 gradually increases as the radius of the sector segment increases, so as to realize the modulation of depth variation.

[0055] Of course, in some other embodiments, Figure 3 Only one embodiment is shown in the figure, and the radius of each sector is different. This belongs to other patterned baffles and also falls within the scope of protection of the present invention.

[0056] Based on the above embodiment, the present invention further defines that sector-shaped substrate 10 has a central angle α, which is the angle enclosed by the straight lines on the outermost edge of the sector segment, and sector-shaped substrate 20 has a central angle β, which is formed by multiple sector segments arranged adjacent to each other. The central angle β is the angle enclosed by the straight lines on the outermost edge, and α is not equal to β, such as α is greater than β, or α is less than β. Alternatively, α is equal to β. The specific size of the central angle or the relative size relationship is not limited by the present invention. Those skilled in the art can define the size of the sector central angle based on etching requirements, and this can be determined by those skilled in the art.

[0057] Alternatively, further, the central angle α is limited to be greater than 180° and less than 270°.

[0058] like Figure 2~Figure 3 As shown, in one embodiment, the centers of the sector-shaped substrate 10 and the sector-shaped substrate 2 20 coincide with each other and their edges are adjacently spliced.

[0059] like Figure 5As shown, in another embodiment, a patterned baffle has a special shape. This special shape is the substrate shape obtained by concentrically removing the area of ​​the same shape as the second sector substrate 20 from the first sector substrate 10. Specifically, the first sector substrate 10 includes at least one basic sector; the second sector substrate 20 includes at least one extended sector; the radius of the extended sector is smaller than that of the basic sector, and when there are more than one extended sector, each extended sector is concentrically arranged with adjacent edges and has different radii. It can also be simply understood as the structure of the patterned baffle being the structure of the first sector substrate 10 minus the projected area of ​​the second sector substrate 20 on the first sector substrate 10.

[0060] Optionally, in Figures 1 to 3 In the embodiment of the present invention, the patterned baffle is formed by splicing the edges of the sector-shaped substrate 10 and the sector-shaped substrate 20. Figure 5 In the embodiment, the patterned baffle is obtained by subtracting the projection area of ​​the sector-shaped substrate 20 from the sector-shaped substrate 10. Figure 5 In the embodiment, Figure 3 The embodiment is a complementary structure. It should be noted that this embodiment is for illustration only and does not limit the sector-shaped substrate 1 in the previous embodiment and the sector-shaped substrate 1 in this embodiment to being the same substrate, and their central angles may be different; nor does it limit the sector-shaped substrate 2 in the previous embodiment and the sector-shaped substrate 2 in this embodiment to being the same substrate, and their central angles may be different, and the number and radius of the included diffusion sectors may also be different.

[0061] The present invention further describes the etching process based on the patterned baffle.

[0062] like Figure 3 and Figure 4 As shown, based on the radius of different fan-shaped segments, the cross-sectional area of ​​different depth regions is determined, as shown in FIG. Figure 3 As shown, d1=r b1 , d2=r b2 -r b1 , d3=r b3 -r b2 , d4=r b4 -r b3 , d a =r a -r b4 Therefore, according to the requirements of the area size of different etching depth regions, the radius of adjacent sectors can be controlled to determine the size, that is, to control d1, d2, d3, d4, d a The relative size of can control the cross-sectional area of ​​each etched area. Figure 4 As shown, the baffle provided by the present invention can obtain etching areas with different depths. aThe size and Figure 3 The relative protrusion length of each sector corresponds to the relative protrusion length of each sector, that is, the cross-sectional area of ​​each etched region is related to the radius of the adjacent sector.

[0063] Of course, the relative difference in the radii of different sectors can be used to determine the areas d1, d2, d3, d4, and d5 formed by etching. a The size of d1≠d2≠d3≠d4≠d a , that is, each area can be modulated to have different depths, such as Figure 8 As described above, based on different etching results, the radius of the corresponding arc segment can be determined according to the size of the different etching areas.

[0064] Furthermore, based on Figures 1 to 3 An embodiment of a depth control method, such as Figure 6 As shown, a substrate 100 is provided, a graphic mask layer is set on the substrate 100, and the substrate 100 with the graphic mask layer is etched based on the graphic baffle provided in any of the aforementioned embodiments to obtain optical structure areas with different etching depths in different areas, such as a grating structure; the graphic mask layer is removed to obtain the required optical structures of different depths.

[0065] As is known in the art, for a diffraction optical waveguide, light continuously interacts with the diffraction grating structure as it is transmitted therein, resulting in energy attenuation. This requires that the diffraction efficiency be different in different areas as the light is transmitted, in order to balance the energy attenuation and improve uniformity. In the present application, the diffraction efficiency of the diffraction grating structure is modulated by depth modulation, and it is necessary to make the outcoupling grating structure of the diffraction optical waveguide have a specific depth variation distribution. Therefore, the baffle provided by the present invention can make the etching depth different in different etching areas. At the same time, it can also be achieved that the depth of the etched grating structure is the same within the same etching area, such as within a sector segment of the same radius, the etching depth remains the same, which is conducive to the modulation of different diffraction efficiencies, thereby improving the display effect of the waveguide.

[0066] Specifically, the depth control method of the micro-nano optical structure includes:

[0067] Providing a substrate and the patterned baffle provided by any of the above embodiments;

[0068] forming a patterned mask layer on a substrate; wherein a patterned area of ​​the patterned mask layer is a target area where a micro-nano optical structure is to be formed, and a position of the patterned area is selected so that a target depth variation direction of the micro-nano optical structure is consistent with a radial direction of the substrate;

[0069] The patterned baffle is coaxially arranged with the substrate, the patterned baffle or the substrate is rotated and the substrate is etched, so that the substrate is partially shielded by the patterned baffle during etching, thereby obtaining micro-nano optical structures with several different depths on the substrate.

[0070] In practice, the substrate is implemented as a circular substrate, and the radius is consistent with the radius of the basic sector in the patterned baffle. In addition, since the depth variation of the patterned baffle depends on the number of its sector segments and the radius setting of each sector segment, its effect on etching is to produce a depth variation in the radial direction. Therefore, when designing the position of the diffraction grating structure area on the substrate, it is necessary to select the position of the patterned area so that the target depth variation direction of the micro-nano optical structure is consistent with the radial direction of the substrate, so that the depth variation etched in the patterned area meets the requirements of the diffraction efficiency distribution. Among them, the patterned area of ​​the patterned mask layer is the target area to be formed with the micro-nano optical structure, and the patterned area has an etching window, so that etching of the substrate can be formed, thereby obtaining a micro-nano optical structure with a depth variation; the surface of the substrate outside the patterned area is completely covered with a mask and has no window, so that the substrate in this area can be protected.

[0071] For example, refer to Figure 9 The left figure in the figure is a schematic diagram of a patterned baffle, and the right figure is a schematic diagram of a substrate. In this example, the micro-nano optical structure to be etched is the outcoupling grating structure of a diffraction optical waveguide. The short dashed line in the figure is a depth partition line. Depending on the number and radius of the extended sectors included in the sector substrate 20, four groups of diffraction grating structure areas of the diffraction optical waveguide are designed on the substrate 300. Among them, the outcoupling structure area of ​​the diffraction optical waveguide is a patterned area 310. The access position of the patterned area 310 on the substrate is selected so that the target depth variation direction of the outcoupling grating structure is consistent with the radial direction of the substrate, thereby relying on the shielding effect of the patterned baffle to obtain the desired depth variation distribution within the patterned area 310. It should be noted that there are more patterning details within the patterned area 310 that are not shown in this figure.

[0072] Further, in another embodiment, a depth control method, such as Figure 7 As shown, a substrate 100 is provided, and the patterned baffle provided by the present invention is used to pre-etch the substrate 100 to form steps with different depths, such as Figure 4 or Figure 8 As shown, after the pre-etching is completed, a patterned mask layer is set on the step surface of different depths on the etched substrate 100, and then the substrate 100 with the patterned mask layer is etched based on the same patterned baffle to form the required depth structure on the substrate 100, and the patterned mask layer is removed to obtain the following Figure 7 The structure shown.

[0073] Specifically, the depth control method of the micro-nano optical structure includes:

[0074] Providing a substrate and the patterned baffle provided by any of the above embodiments;

[0075] forming a patterned sacrificial layer on a substrate, wherein a window region of the patterned sacrificial layer is a target region where a micro-nano optical structure is to be formed, and a position of the window region is selected so that a target depth variation direction of the micro-nano optical structure is consistent with a radial direction of the substrate;

[0076] The patterned baffle is coaxially arranged with the substrate, the patterned baffle or the substrate is rotated, and the substrate is etched so that the substrate is partially shielded by the patterned baffle during etching, thereby forming a plurality of steps of different depths in the window area;

[0077] After removing the remaining patterned sacrificial layer on the substrate, a patterned mask layer is formed on the substrate, wherein the patterned area of ​​the patterned mask layer is consistent with the window area;

[0078] The patterned baffle is coaxially arranged with the substrate, the patterned baffle or the substrate is rotated and the substrate is etched, so that the substrate is partially shielded by the patterned baffle during etching, thereby obtaining micro-nano optical structures with several different depths on the substrate.

[0079] In practice, the substrate is a circular substrate with a radius that is consistent with the radius of the basic sector in the patterned baffle. In this example, a two-stage etching process is performed. In the first stage, a patterned sacrificial layer is formed on the substrate. The patterned sacrificial layer has at least one window area. The entire substrate within the window area is etched to form a number of steps of varying depths. In the second stage, a patterned mask layer is formed on the substrate. The patterned mask layer has at least one patterned area that is consistent with the window area and has an etching window within the patterned area. This allows etching of the substrate to form a micro-nano optical structure with varying depths.

[0080] For example, continue to refer to Figure 9 In this example, the micro-nano optical structure to be etched is the outcoupling grating structure of a diffractive waveguide. Multiple diffraction grating structure regions are designed on substrate 300. Window region 320, or the outcoupling grating region, is selected so that the target depth variation direction of the outcoupling grating structure aligns with the radial direction of the substrate. The entire area within window region 320 is a window.

[0081] certainly, Figure 6 and Figure 7 In the embodiment, optical structures with different depths are obtained based on different process step sequences; Figure 6 The optical structures with different depths are shown as follows: Figure 7 The top of the optical structure shown is not flush and has different depths to suit different requirements.

[0082] In any of the above embodiments, the optical structure prepared is a diffraction grating structure with different depths. That is, the present invention provides a diffraction grating that is etched based on the above depth control method.

[0083] In the above embodiments, during etching, etching to different depths can be achieved by rotating the substrate 100 , or by rotating the patterned baffle in any of the above embodiments. This is achievable.

[0084] At the same time, the present application provides a diffraction grating, which is etched based on the depth control method of the above embodiment.

[0085] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A patterned baffle for preparing a micro-nano optical structure with depth variation, characterized in that: The patterned baffle includes: a fan-shaped substrate 1 and a fan-shaped substrate 2, wherein the center of the fan-shaped substrate 1 coincides with that of the fan-shaped substrate 2 and the edges are adjacent to each other; the fan-shaped substrate 1 includes at least one basic fan-shape; the fan-shaped substrate 2 includes at least one extended fan-shape; the radius of the extended fan-shape is smaller than the radius of the basic fan-shape, and when there is more than one extended fan-shape, each extended fan-shape has the same center, is adjacent to each other at the edges, and has different radii.

2. The patterned baffle according to claim 1, wherein: The micro-nano optical structure is a diffraction grating structure in a diffraction optical waveguide.

3. The patterned baffle according to claim 1, wherein: The depth change includes at least one of a depth gradient change and a depth continuous change.

4. The patterned baffle according to claim 1, wherein: When the sum of the central angles of the first sector-shaped substrate and the second sector-shaped substrate is 360°, the sum of the number of extended sectors in the second sector-shaped substrate is equal to the number of depths of different sizes of the micro-nano optical structure.

5. The patterned baffle according to claim 4, characterized in that: The radius of the extended sector in the second sector-shaped substrate increases or decreases in sequence along the same direction; the opening ratio between the first sector-shaped substrate and the second sector-shaped substrate changes with the change of the radius of the extended sector in the second sector-shaped substrate.

6. A method for controlling the depth of a micro-nano optical structure, characterized in that: The method comprises: Providing a substrate and the patterned baffle according to any one of claims 1 to 5; forming a patterned mask layer on the substrate; wherein the patterned area of ​​the patterned mask layer is a target area where the micro-nano optical structure is to be formed, and the position of the patterned area is selected so that the target depth variation direction of the micro-nano optical structure is consistent with the radial direction of the substrate; The patterned baffle is coaxially arranged with the substrate, the patterned baffle or the substrate is rotated and the substrate is etched so that the substrate is partially shielded by the patterned baffle during etching, thereby obtaining micro-nano optical structures with several different depths on the substrate.

7. A method for controlling the depth of a micro-nano optical structure, characterized in that: The method comprises: Providing a substrate and the patterned baffle according to any one of claims 1 to 5; forming a patterned sacrificial layer on the substrate, wherein a window region of the patterned sacrificial layer is a target region where the micro-nano optical structure is to be formed, and a position of the window region is selected so that a target depth variation direction of the micro-nano optical structure is consistent with a radial direction of the substrate; The patterned baffle is coaxially arranged with the substrate, the patterned baffle or the substrate is rotated, and the substrate is etched so that the substrate is partially shielded by the patterned baffle during etching, thereby forming a plurality of steps of different depths in the window area; After removing the remaining patterned sacrificial layer on the substrate, a patterned mask layer is formed on the substrate, wherein a patterned area of ​​the patterned mask layer is consistent with the window area; The patterned baffle is coaxially arranged with the substrate, the patterned baffle or the substrate is rotated and the substrate is etched so that the substrate is partially shielded by the patterned baffle during etching, thereby obtaining micro-nano optical structures with several different depths on the substrate.

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