A patterning substrate structure and method of manufacture

Abstract

The application relates to the field of semiconductor technology, and provides a patterned substrate structure and a preparation method. The patterned substrate structure comprises, from bottom to top, a substrate layer and a plurality of optical film structures uniformly distributed in the substrate layer; wherein the side surface of the optical film structure is a first arc surface composed of a plurality of same first convex arc lines, the plurality of first convex arc lines extend from the lower surface edge of the optical film structure and intersect at the vertex of the optical film, and the refractive index of the optical film structure is smaller than the refractive index of the substrate layer. The side wall of the patterned substrate structure is an arc surface composed of convex arc lines, and the arc edge is limited in a certain range. Compared with a flat side wall, light is more likely to be totally reflected, and the outward expansion of the side wall increases the effective area of the low-refraction zone, thereby improving the light extraction capability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a patterned substrate structure and a preparation method. BACKGROUND

[0002] In the semiconductor LED industry, in order to obtain higher quality and less dislocation density of epitaxial layers, three kinds of patterned sapphire substrates, silicon carbide substrates and silicon substrates are commonly used as growth carriers for epitaxy, among which sapphire substrates are the most widely used. At present, in order to improve the brightness of LED chips, hetero-material composite substrates have gradually become the mainstream direction, and the technology tends to be mature and enters mass production.

[0003] The conventional hetero-material composite substrate commonly adopts a regularly arranged conical shape as shown in FIGS. 1 to 3 as a substrate pattern, but it has the problem of low light reflectivity at the substrate pattern, resulting in low light extraction efficiency of the LED chip. Figure 1 、 Figure 2

[0004] Therefore, how to improve the light extraction efficiency of the LED chip becomes a problem to be solved. SUMMARY

[0005] To solve the above-mentioned problem of low light extraction efficiency of the conventional hetero-material composite substrate LED in the prior art, the present application provides a patterned substrate structure, which comprises a substrate layer and a plurality of optical film structures uniformly distributed on the substrate layer, the substrate layer comprises a base and an over-etching portion from bottom to top, and the optical film structure is arranged on the upper surface of the over-etching portion.

[0006] Among them, the side surface of the optical film structure is a first arc surface composed of a plurality of identical first convex arc lines, the plurality of first convex arc lines extend from the edge of the lower surface of the optical film structure and intersect at the vertex of the optical film structure, and the refractive index of the optical film structure is less than the refractive index of the substrate layer.

[0007] The first convex arc line extends to the upper surface of the base to form a second convex arc line, the second convex arc line has the same radius of curvature as the first convex arc line, and the ratio of the arc edge distance of the second convex arc line to the length of the line segment connected to the end point of the second convex arc line ranges from 0.04 to 0.12.

[0008] In an embodiment, the side surface of the over-etching portion is a second arc surface composed of a plurality of identical third convex arc lines, and the upper surface of the over-etching portion matches the lower surface of the optical film structure.

[0009] In an embodiment, the line segment connected to the end point of the first convex arc line forms a first angle with the lower surface of the optical film layer, and the line segment connected to the end point of the third convex arc line forms a second angle with the lower surface of the over-etching portion, and the second angle is smaller than the first angle.

[0010] ​In an embodiment, the first angle is 5° to 20° different from the second angle.

[0011] In an embodiment, the optical thin film has a thickness of 0.7 μm to 2.5 μm.

[0012] In an embodiment, the over-etching portion has a thickness of 0.1 μm to 0.8 μm.

[0013] In an embodiment, the lower surface of the over-etching portion has a diameter of 2.5 μm to 3.5 μm.

[0014] In an embodiment, the substrate layer is made of sapphire.

[0015] In an embodiment, the optical thin film structure is made of one or more of SiO2, Si3N4, ZnO2, Si, SiC, GaAs, Ti3O5, and TiO2.

[0016] In an embodiment, the optical thin film structure is a single layer.

[0017] In an embodiment, the optical thin film structure is provided in multiple layers.

[0018] The present application also provides a method for preparing a patterned substrate structure, comprising the following steps:

[0019] growing an optical thin film on the substrate layer;

[0020] applying a photoresist of a predetermined thickness on the upper surface of the optical thin film, and using a compression or exposure development method to produce uniformly distributed cylindrical photoresist columns;

[0021] using dry etching RFT / RFB power to etch the optical thin film between adjacent photoresist columns, to obtain an optical thin film structure with a first arc-shaped side wall;

[0022] etching the optical thin film structure with the first arc-shaped side wall to obtain an over-etching portion with a second arc-shaped side wall, and determining the wafer height of the substrate layer, to obtain the patterned substrate structure according to any one of the embodiments described above.

[0023] Based on the above, compared with the prior art, the present application provides the following beneficial effects:

[0024] 1. The patterned substrate structure of the present application is composed of a substrate layer and an optical thin film structure, the optical thin film structure is a low refractive index material, the substrate layer is a high refractive index material, light enters the low refractive index material from the high refractive index material, the incidence angle is greater than the critical angle, total reflection is more likely to occur, and the surface nucleation of the optical thin film structure is more uniform during epitaxy, which reduces epitaxial defects.

[0025] 2. The graphical substrate structure of the present application, the side wall is arc surface composed of convex arc, compared with flat side wall, light is more likely to be totally reflected, and the outward expansion of the side wall increases the effective area of the low-refraction zone, improving the light extraction capability.

[0026] 3. The graphical substrate structure of the present application, the side wall is divided into first arc surface and second arc surface, the side wall curvature radius of the first arc surface and the second arc surface is different, which can reflect more light of different incident angles, so that the probability of total reflection of light is greater.

[0027] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and attained by the structure particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor; In the following description, the positional relationship described in the drawings is the direction of the components drawn in the drawing as the reference, unless otherwise specified.

[0029] Figure 1 It is a side structure schematic diagram of the prior art substrate structure;

[0030] Figure 2 It is a top view structure schematic diagram of the prior art substrate structure;

[0031] Figure 3 It is a structure schematic diagram of the graphical substrate structure provided by the first embodiment of the present application;

[0032] Figure 4 It is another structure schematic diagram of the graphical substrate structure provided by the first embodiment of the present application;

[0033] Figure 5 It is a structure schematic diagram of the graphical substrate structure after circle fitting in the coordinate system provided by the first embodiment of the present application;

[0034] Figure 6 It is an angle structure schematic diagram of the graphical substrate structure provided by the first embodiment of the present application;

[0035] Figure 7 It is a structure schematic diagram of different arc edge distances of the graphical substrate structure provided by the first embodiment of the present application;

[0036] Figure 8 Flow chart of the method for preparing the patterned substrate structure provided in Embodiment Two of the present application;

[0037] Figure 9 Schematic diagram of the method for preparing the patterned substrate structure provided in Embodiment Two of the present application;

[0038] Figure 10 Another schematic diagram of the method for preparing the patterned substrate structure provided in Embodiment Two of the present application;

[0039] Figure 11 Schematic diagram of the processing procedure of the method for preparing the patterned substrate structure provided in Embodiment Two of the present application;

[0040] Figure 12 Schematic diagram of the structure after the method for preparing the patterned substrate structure provided in Embodiment Two of the present application is processed.

[0041] Reference signs:

[0042] 10, substrate layer; 11, base; 12, over-etching part; 121, third outer convex arc line; 20, optical film; 21, optical film structure; 211, first outer convex arc line; 212, second outer convex arc line; 30, photoresist column. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application; as long as there is no conflict, the technical features in the different implementation manners described below can be combined with each other; based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0044] In the description of the present application, it should be noted that all the terms (including technical terms and scientific terms) used in the present application have the same meanings as those generally understood by a person of ordinary skill in the art to which the present application belongs, and should not be understood as a limitation on the present application; it should be further understood that the terms used in the present application should be understood as having the same meanings as the meanings of these terms in the context of the present specification and the related art, and should not be understood in an idealized or overly formal sense, except as expressly defined in the present application.

[0045] Embodiment One

[0046] A patterned substrate structure, such as Figure 3As shown, the substrate layer 10 includes a base 11 and an over-etching portion 12 from bottom to top, and a plurality of optical film structures 21 are uniformly distributed on the substrate layer 10, and the optical film structures 21 are arranged on the upper surface of the over-etching portion 12;

[0047] The side surface of the optical film structure 21 is a first arc surface composed of a plurality of identical first convex arc lines 211, the plurality of first convex arc lines 211 extend from the lower surface edge of the optical film structure 21 and intersect at the vertex of the optical film structure 21, and the refractive index of the optical film structure 21 is less than the refractive index of the substrate layer 10.

[0048] The first convex arc line 211 extends to the upper surface of the base 11 to form a second convex arc line 212, and the curvature radius of the first arc line 211 is the same as that of the second arc line 212. The maximum vertical distance of the line segment between the top and bottom endpoints of the second convex arc line 212 to the second convex arc line is the arc edge distance, which reflects the convexity of the side wall of the pattern. The ratio of the arc edge distance of the second convex arc line 212 to the length of the line segment connected to the endpoints of the second convex arc line 212 should be in the range of 0.04 to 0.12. Within this range, the light extraction efficiency is the highest. If the ratio is too low, such as less than 0.04, the volume of the low-refraction region is too small, and the side wall of the low-refraction region is too flat, which is not conducive to total reflection of light at the pattern structure and will be absorbed by the substrate, resulting in a decrease in brightness and affecting the light extraction efficiency. If the ratio is too high, the arc edge distance is too large, and the side wall of the low-refraction region is too convex, tending to be hemispherical, which causes the angle of light reflection to be large, and the light is easily trapped in the epitaxial structure and the substrate, which is not conducive to subsequent transmission to the air, greatly affecting the light extraction efficiency.

[0049] Specifically, the optical film structure 21 can be a pattern similar to a shell with a wide lower part and a narrow top part, the top size is 0 μm, and the bottom size is 0.5 μm-6 μm. The substrate layer 10 below the optical film structure 21 can be a flat surface or a circular truncated cone structure with a large bottom surface and a small top surface, the top size of the circular truncated cone is 0.5 μm-6 μm, and the bottom size is 0.8 μm-10 μm. The patterned substrate structure has an array of regular composite patterns.

[0050] The side wall of the optical film structure 21 is an arc-shaped side wall. Compared with a flat side wall, the arc-shaped side wall can reflect more angles of incident light, so it is more conducive to total reflection of light. At the same time, the arc-shaped side wall can extend the area of the optical film structure 21 to some extent, increase the effective area of the low-refraction region, and make the total reflection area of light larger, which is more conducive to total reflection of light.

[0051] The substrate 10 uses a high-refractive-index material, preferably sapphire; the optical thin film structure 21 uses a low-refractive-index material, which can be one or more of SiO2, Si3N4, ZnO2, Si, SiC, GaAs, Ti3O5, and TiO2, preferably SiO2. The use of a low-refractive-index heterogeneous material in the upper optical thin film structure 21 facilitates light reflection, reduces epitaxial defects, and improves the brightness of the LED chip.

[0052] Preferably, the thickness of the optical thin film 20 is between 0.7 μm and 2.5 μm. Within this range, the pattern can provide a sufficient area of ​​low-refractive-index region without being too thick, resulting in a relatively stable substrate structure and high reliability. The optical thin film structure 21 can be a single layer or multiple layers.

[0053] In specific implementation, the optical thin film structure 21 can be a single-layer structure made of one of the following materials: SiO2, Si3N4, ZnO2, Si, SiC, GaAs, Ti3O5, and TiO2, or it can be a composite material graphic structure made of a combination of the above materials.

[0054] In one embodiment, the substrate layer 10 includes a base 11 and an over-etched portion 12. The side of the over-etched portion 12 is a second arc-shaped surface composed of several identical third convex arc lines 121. The curvature radius of the third convex arc lines 121 is inconsistent with that of the first convex arc lines 211. The upper surface of the over-etched portion 12 matches the lower surface of the optical thin film structure 21.

[0055] like Figure 4 As shown, the first convex arc 211 extends to the upper surface of the base 11 to form a second convex arc 212. The second convex arc 212 has the same radius of curvature as the first convex arc 211. The ratio of the arc edge distance of the second convex arc 212 to the length of the line segment connecting the endpoint of the second convex arc 212 ranges from 0.04 to 0.12. Figure 5 As shown in the diagram, EF represents the arc edge distance, which is the maximum perpendicular distance between the line segment BD connecting the endpoints of the second convex arc 212 and the second convex arc. With the lower surface diameter AB of the optical thin film structure extending to the base and the line segment CD from the base to the vertex of the optical thin film structure remaining unchanged, the arc edge distance in this embodiment can specifically be 0.1 μm < EF < 0.3 μm.

[0056] Preferably, in this embodiment, the specific value of the arc edge distance can also be 0.15μm < EF < 0.2μm.

[0057] The specific fitting derivation process is as follows: Figure 5As shown, after obtaining the side profile of the PSS through AFM, the arc radius OF of the side profile of the optical thin film structure 21 is obtained by arc fitting. Here, arc DG is the first convex arc 211, line segment AB is the diameter of the lower surface of the optical thin film structure extending to the base, arc DB is the second convex arc 212, line segment DB is the line segment connecting the endpoints of the second convex arc 212, arc radius OF⊥line segment DB, the intersection point is E, and the arc edge distance is equal to the length EF. Therefore:

[0058] EF = OF - OE

[0059] OE² = OB² - EB² (in right triangle OEB)

[0060] OB=OF

[0061] EB=1 / 2DB

[0062] DB² = CD² + CB² (in right triangle DCB)

[0063] CB = 1 / 2AB

[0064] but

[0065] The ratio of the arc edge distance of the second convex arc 212 to the length of the line segment connecting the endpoint of the second convex arc 212 ranges from 0.04 to 0.12; in this embodiment, the specific range of the arc edge moment is 0.1μm < EF < 0.3μm.

[0066] Specifically, if the arc edge distance is too small, the sidewalls will be relatively flat, which is not conducive to total internal reflection of light at the pattern structure. At the same time, the effective area of ​​the low-refractive region is small, resulting in a correspondingly lower light extraction efficiency. The larger the arc edge distance, the larger the volume of the low-refractive region in the heterogeneous material pattern. More light rays enter the low-refractive-index material from the high-refractive-index material. Compared to light entering the air directly from the high-refractive-index region, this design can further increase the probability of total internal reflection and improve the light extraction efficiency. If the arc edge distance is too large, the top of the pattern will not be pointed, and the pattern will be close to a hemisphere. This will change the light path of the light rays hitting the top of the pattern. The light will not easily penetrate into the external air, but will be reflected back to the epitaxial layer and the interior of the substrate, reducing the light extraction efficiency. Therefore, in this embodiment, 0.1μm < EF < 0.3μm is set, which can ensure the light extraction efficiency and also ensure that the top shape of the optical thin film structure 21 does not change too much.

[0067] Better, such as Figure 6 As shown, the line segment connecting the endpoints of the first convex arc 211 forms a first angle with the lower surface of the optical thin film 20 layer; the line segment connecting the endpoints of the third convex arc 121 forms a second angle with the lower surface of the etched portion 12, and the second angle is smaller than the first angle.

[0068] Specifically, if the etched portion 12 has the same curvature as the sidewall of the optical thin film structure 21, then the sidewall has only one angle, and can only undergo total internal reflection of light in a single direction; while in this application... Figure 6 As shown, the difference in size between the first angle a1 and the second angle a2 makes the over-etched part 12 and the optical thin film structure 21 have a two-section sidewall structure, which enables it to undergo total internal reflection of light from multiple directions. The probability of total internal reflection of incident light is greater than that of a single angle, which greatly improves the probability of total internal reflection of light.

[0069] Preferably, the difference between the first angle and the second angle is 5° to 20°. Specifically, the greater the difference between the first angle a1 and the second angle a2, the gentler the slope of the etched portion 12 compared to the optical thin film structure 21, making it more suitable for the falling of the optical thin film structure 21 and allowing the optical thin film 20 to grow well during the fabrication process. If the difference in angle is less than 5°, the slope difference between the etched portion 12 and the optical thin film structure 21 is too small to improve the probability of total internal reflection; while when the difference in angle is greater than 20°, it will make the substrate structure unstable, affecting the light extraction effect and reliability.

[0070] Preferably, the thickness of the over-etched portion 12 is 0.1 μm to 0.8 μm. In specific implementations, the epitaxial layer of the LED chip can only be grown on the sapphire substrate 10 and cannot be grown directly on the optical thin film structure 21. Therefore, the over-etched portion 12 is provided. When the thickness of the over-etched portion 12 is less than 0.1 μm, the epitaxial layer cannot grow well; when the thickness of the over-etched portion 12 is greater than 0.8 μm, the proportion of the optical thin film structure 21 will decrease, thus affecting total internal reflection. Therefore, the optimal thickness range for the over-etched portion 12 is 0 μm to 0.8 μm. The diameter of the lower surface of the over-etched portion 12 is 2.5 μm to 3.5 μm.

[0071] like Figure 7 As shown, (a) is a patterned substrate structure with an arc edge distance of 0.113 μm, (b) is a patterned substrate structure with an arc edge distance of 0.116 μm, (c) is a patterned substrate structure with an arc edge distance of 0.168 μm, and (d) is a patterned substrate structure with an arc edge distance of 0.179 μm. The existing substrate structures and... Figure 7 The products manufactured using four different substrate structures with varying arc edge distances were tested for their lamp repair luminance and MAP-VF. The test results are shown in Table 1.

[0072] Table 1

[0073]

[0074] As shown in Table 1, the LED lamp package repair brightness of the LED lamp package using the graphic substrate structure of the present application is greater than that of the LED lamp package using the prior art substrate structure; in particular, the higher the LED lamp package repair brightness, the better. The MAP-VF of the LED lamp using the (c) and (d) arc edge distance graphic substrate structure of the present application is less than that of the LED lamp using the prior art substrate structure; in particular, the lower the MAP-VF, the better the LED lamp brightness.

[0075] Embodiment Two

[0076] The present application also provides a method for preparing a graphic substrate structure, as shown in Figure 8 The method comprises the following steps:

[0077] Performing optical film 20 growth on the substrate layer 10;

[0078] Smearing a preset thickness of photoresist on the surface of the optical film 20, and using the imprint or exposure development method to produce uniformly distributed cylindrical photoresist columns 30;

[0079] Using dry etching RFT / RFBpower to etch the optical film 20 between adjacent photoresist columns 30 to obtain an optical film structure 21 with a first arc-shaped side wall;

[0080] According to the etching of the optical film structure 21 with a first arc-shaped side wall, an over-etching portion 12 with a second arc-shaped side wall is obtained, and the wafer height of the substrate layer 10 is determined, to obtain the graphic substrate structure as described in the above embodiments.

[0081] In an embodiment, the preset thickness of the photoresist is 0.5 μm to 5 μm.

[0082] In particular implementation, as shown in Figure 9 First, a layer or multiple layers of optical film 20 are covered on the surface of the Al2O3 wafer, and the material of the optical film 20 can be one of SiO2, Si3N4, ZnO2, Si, SiC, GaAs, Ti3O5, TiO2, or a composite material film composed of multiple materials described above, and the thickness of the optical film 20 is 0.1-15 μm.

[0083] As shown in Figure 10 The surface of the optical film 20 is processed by photolithography, a layer of photoresist is first coated, with a thickness of about 0.5-5 μm, and then the imprint or exposure development method is used to produce cylindrical photoresist columns 30 with a period of 0.5-10 μm, and the bottom width of the cylindrical photoresist columns 30 is about 0.5-9.5 μm.

[0084] As shown in Figure 11As shown, the optical film structure 21 between the adjacent photoresist columns 30 is etched by dry etching RFT / RFB power and other debugging, to obtain the optical film structure 21 with a first arc surface, the etching depth is 0.5-10 μm, to obtain the shell pattern with a certain arc edge distance, the arc edge distance is 0.15 μm < EF < 0.3 μm, and the etching Al2O3 wafer height is determined according to the final pattern, the height is preferably 0-3 μm, to form the substrate pattern structure as shown. Figure 12 As shown, the optical film structure 21 between the adjacent photoresist columns 30 is etched by dry etching RFT / RFB power and other debugging, to obtain the optical film structure 21 with a first arc surface, the etching depth is 0.5-10 μm, to obtain the shell pattern with a certain arc edge distance, the arc edge distance is 0.15 μm < EF < 0.3 μm, and the etching Al2O3 wafer height is determined according to the final pattern, the height is preferably 0-3 μm, to form the substrate pattern structure as shown.

[0085] In addition, those skilled in the art should understand that although there are many problems in the prior art, each embodiment or technical solution of the present application can only improve in one or several aspects, and it is not necessary to solve all the technical problems listed in the prior art or background art at the same time. Those skilled in the art should understand that what is not mentioned in a claim should not be regarded as a limitation of the claim.

[0086] Although terms such as substrate layer, base, over-etching part, second arc surface, optical film structure, first arc surface and photoresist column are used more in this paper, but it does not exclude the possibility of using other terms. The use of these terms is only to facilitate the description and explanation of the essence of the present application; any additional limitation is contrary to the spirit of the present application; the terms "first", "second", etc. (if any) in the specification and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0087] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A patterned substrate structure, characterized in that: The device includes a substrate layer and several optical thin film structures uniformly distributed on the substrate layer. The substrate layer includes a base and an over-etched portion from bottom to top. The optical thin film structures are disposed on the upper surface of the over-etched portion. The optical thin film structure has a side surface composed of several identical first convex arc lines. The several first convex arc lines extend from the lower surface edge of the optical thin film structure and intersect at the vertex of the optical thin film structure. The refractive index of the optical thin film structure is less than the refractive index of the substrate layer. The first convex arc extends to the upper surface of the base to form a second convex arc. The second convex arc has the same radius of curvature as the first convex arc. The ratio of the arc edge distance of the second convex arc to the length of the line segment connecting the endpoint of the second convex arc is in the range of 0.04 to 0.

12. The side of the etched portion is a second arc-shaped surface composed of several identical third convex arc lines; the line segment connecting the endpoints of the first convex arc lines forms a first angle with the lower surface of the optical thin film layer; the line segment connecting the endpoints of the third convex arc lines forms a second angle with the lower surface of the etched portion; the second angle is smaller than the first angle; the difference between the first angle and the second angle is 5° to 20°.

2. The patterned substrate structure according to claim 1, characterized in that: The upper surface of the over-etched portion matches the lower surface of the optical thin film structure.

3. The patterned substrate structure according to claim 1, characterized in that: The thickness of the optical thin film structure is from 0.7 μm to 2.5 μm.

4. The patterned substrate structure according to claim 1, characterized in that: The thickness of the etched portion is 0.1 μm to 0.8 μm.

5. The patterned substrate structure according to claim 1, characterized in that: The diameter of the lower surface of the etched portion is 2.5 μm to 3.5 μm.

6. The patterned substrate structure according to claim 1, characterized in that: The substrate is made of sapphire.

7. The patterned substrate structure according to claim 1, characterized in that: The optical thin film structure is made of one or more of the following materials: SiO2, Si3N4, ZnO2, Si, SiC, GaAs, Ti3O5, and TiO2.

8. The patterned substrate structure according to claim 1, characterized in that: The optical thin film structure is a single layer.

9. The patterned substrate structure according to claim 1, characterized in that: The optical thin film structure has multiple layers.

10. A method for fabricating a patterned substrate structure, characterized in that, Includes the following steps: Optical thin film growth is performed on a substrate layer; A photoresist of a predetermined thickness is coated on the upper surface of the optical thin film, and a uniformly distributed cylindrical photoresist column is produced by imprinting or exposure development. The optical film between adjacent photoresist pillars is etched using dry etching RFT / RFB power to obtain an optical film structure with a first arc-shaped sidewall. An over-etched portion with a second arcuate sidewall is obtained by etching the optical thin film structure with a first arcuate sidewall, and the wafer height of the substrate layer is determined at the same time to obtain the patterned substrate structure as described in any one of claims 1-9.

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