A wrapped patterned composite substrate, preparation method and LED epitaxial wafer

Abstract

The embodiment of the present invention discloses a wrapped patterned composite substrate, a preparation method and an LED epitaxial wafer. The wrapped patterned composite substrate includes a substrate substrate and a plurality of composite patterned microstructures formed on the substrate substrate; the composite patterned microstructure includes a central protruding microstructure and a crater-shaped annular protruding microstructure, the bottom of the central protruding microstructure is integrally connected to the substrate substrate, and the crater-shaped protruding microstructure is made of a heterogeneous material; the crater-shaped annular protruding microstructure is arranged around the central protruding microstructure, and wraps the bottom of the central protruding microstructure, exposing the top of the central protruding microstructure. The embodiment of the present invention solves the problem that the C-surface of the existing patterned composite substrate has defects and low light emission efficiency, and can increase the interface area and inclination angle of the composite patterned microstructure with a refractive index difference, thereby improving the light emission probability; at the same time, it can reduce the dislocation density of the epitaxial material during epitaxial growth, and improve the crystallization quality of the epitaxial material.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of LED patterned substrates, and in particular to a wrapped patterned composite substrate, a preparation method and an LED epitaxial wafer. Background Art

[0002] Patterned substrates are widely used in GaN-based LEDs and are a common technology route for commercial LEDs. Using patterned sapphire substrates to grow LED epitaxial wafers is currently recognized by the industry as the most effective way to reduce the dislocation density of epitaxial materials and increase chip brightness.

[0003] In order to further improve the crystal quality of epitaxial materials, increase chip brightness, and meet device performance requirements, the industry has developed a composite patterned substrate, depositing one or more layers of heterogeneous materials on the surface of a sapphire substrate, and then performing patterned etching to obtain a patterned composite substrate. Because the refractive index of the heterogeneous material is different from that of sapphire and gallium nitride, there is a certain refractive index difference. Therefore, the refractive index difference of the heterogeneous material can be used to change the transmission path of light, reduce the probability of light being unable to escape due to total reflection, and improve light extraction efficiency.

[0004] However, the current patterned composite substrates are made of heterogeneous materials stacked in layers, and the pattern of the patterned substrate is single, which has limited effect on improving the light extraction efficiency of LED chips. With the increasingly high performance requirements of LED devices, new patterned substrates need to be developed to meet their technical requirements. Summary of the invention

[0005] The invention provides a wrapped patterned composite substrate, a preparation method and an LED epitaxial wafer, so as to increase the area and the tilt angle of the interface with a refractive index difference in the composite patterned microstructure and reduce the dislocation density of the epitaxial material.

[0006] In a first aspect, an embodiment of the present invention provides a wrapped patterned composite substrate, comprising a substrate base plate and a plurality of composite patterned microstructures formed on the substrate base plate;

[0007] The composite graphic microstructure includes a central protruding microstructure and a crater-like annular protruding microstructure, the bottom of the central protruding microstructure is integrally connected to the substrate, and the crater-like protruding microstructure is made of a heterogeneous material;

[0008] The crater-like annular protruding microstructure is arranged around the central protruding microstructure and wraps the bottom of the central protruding microstructure, exposing the top of the central protruding microstructure.

[0009] Optionally, the height of the central protruding microstructure is greater than or equal to the height of the crater-like protruding microstructure.

[0010] Optionally, the base substrate is exposed between two adjacent composite pattern microstructures.

[0011] Optionally, the central protruding microstructure is any one of a terrace-shaped microstructure, a columnar microstructure, a cone-shaped microstructure, a terrace-like microstructure and a cone-like microstructure.

[0012] Optionally, the central protruding microstructure includes an upper portion and a lower portion, and an inclination angle of a side wall of the upper portion is smaller than an inclination angle of a side wall of the lower portion.

[0013] Optionally, the central raised microstructure includes an upper portion, a middle portion and a lower portion, the upper portion is made of a heterogeneous material, and the lower portion, the middle portion and the substrate are integrally connected.

[0014] Optionally, the side wall of the crater-like annular protrusion microstructure is arc-shaped.

[0015] Optionally, the substrate is made of materials including sapphire, silicon, silicon carbide, gallium nitride, silicon nitride, zinc oxide and spinel; and the heterogeneous materials include oxides, nitrides, carbides and single substances.

[0016] In a second aspect, an embodiment of the present invention further provides an LED epitaxial wafer, comprising a wrapped patterned composite substrate as described in any one of the first aspects.

[0017] In a third aspect, an embodiment of the present invention further provides a method for preparing a wrapped patterned composite substrate, which is used to prepare the wrapped patterned composite substrate as described in any one of the first aspects, and the preparation method comprises:

[0018] Providing a substrate, and patterning a central protruding microstructure on the substrate;

[0019] forming a heterogeneous material layer on the substrate;

[0020] The heterogeneous material layer is patterned to form a crater-like annular protrusion microstructure; wherein the crater-like annular protrusion microstructure is arranged around the central protrusion microstructure and wraps the bottom of the central protrusion microstructure to expose the top of the central protrusion microstructure.

[0021] Optionally, a substrate is provided, and a central protruding microstructure is patterned on the substrate, comprising:

[0022] forming a first photoresist layer on the substrate;

[0023] Patterning the first photoresist layer to form a first photoresist column mask;

[0024] The base substrate is etched according to the first glue column mask to form the central protruding microstructure.

[0025] Optionally, patterning the heterogeneous material layer to form a crater-like annular protruding microstructure includes:

[0026] forming a second photoresist layer on the heterogeneous material layer;

[0027] Patterning the second photoresist layer to form a second photoresist column mask;

[0028] According to the second glue column mask, the heterogeneous material layer is subjected to at least one main etching, and the crater-like annular protruding microstructure is formed.

[0029] Optionally, after the heterogeneous material layer is mainly etched according to the second glue column mask to form the crater-like annular protrusion microstructure, the method further includes:

[0030] The crater-like annular protrusion microstructure is over-etched to modify the graphic morphology of the crater-like annular protrusion microstructure and the central protrusion microstructure.

[0031] Optionally, according to the second glue column mask, the heterogeneous material layer is subjected to at least one main etching to form the crater-like annular protrusion microstructure, including:

[0032] According to the second glue column mask, the heterogeneous material layer is mainly etched at least once, and the central protruding microstructure is etched at the same time; wherein the central protruding microstructure includes an upper part and a lower part, and the sidewall inclination angle of the upper part is smaller than the sidewall inclination angle of the lower part.

[0033] Optionally, the thickness of the heterogeneous material layer is greater than the height of the central protruding microstructure;

[0034] According to the second glue column mask, the heterogeneous material layer is patterned to form the crater-like annular protrusion microstructure, including:

[0035] According to the second glue column mask, the heterogeneous material layer is subjected to at least one main etching, and the central protruding microstructure is etched at the same time; wherein the central protruding microstructure includes an upper part, a middle part and a lower part, the upper part is made of a heterogeneous material, and the lower part, the middle part and the substrate are integrally connected.

[0036] The wrapped patterned composite substrate, preparation method and LED epitaxial wafer provided by the embodiment of the present invention are provided with a substrate substrate and a plurality of composite patterned microstructures formed on the substrate substrate, wherein the composite patterned microstructure includes a central protruding microstructure and a crater-like annular protruding microstructure, the bottom of the central protruding microstructure is integrally connected with the substrate substrate, the crater-like annular microstructure is made of heterogeneous materials, the crater-like annular protruding microstructure is arranged around the central protruding microstructure, and the bottom of the central protruding microstructure is wrapped to expose the top of the central protruding microstructure, which can solve the problem that the C surface of the existing patterned composite substrate has defects and the light emission efficiency is low, and the interface area and the inclination angle of the composite patterned microstructure with a refractive index difference are increased, so that the transmission path of the light can be changed and the light emission probability can be improved. In addition, the wrapped patterned composite substrate with the composite patterned microstructure of the present invention can reduce the dislocation density of the epitaxial material during epitaxial growth and improve the crystallization quality of the epitaxial material. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of a wrapped patterned composite substrate provided by an embodiment of the present invention;

[0038] Figure 2 It is a flow chart of a method for preparing a wrapped patterned composite substrate provided by an embodiment of the present invention;

[0039] Figure 3 yes Figure 2 The structural flow chart of the wrapped graphic composite substrate shown;

[0040] Figure 4 is a schematic structural diagram of another wrapped patterned composite substrate provided by an embodiment of the present invention;

[0041] Figure 5 yes Figure 1 A top view of the wrapped patterned composite substrate shown;

[0042] Figure 6 yes Figure 1 A partial enlarged view of the wrapped patterned composite substrate shown;

[0043] Figure 7 is a partially enlarged schematic diagram of another wrapped patterned composite substrate provided by an embodiment of the present invention;

[0044] Figure 8 is a flow chart of another method for preparing a composite patterned substrate provided by an embodiment of the present invention;

[0045] Fig. 9 yes Figure 8 The structural flow chart of the composite patterned substrate shown;

[0046] Fig.10 is a flow chart of another method for preparing a composite patterned substrate provided by an embodiment of the present invention;

[0047] Fig.11 yes Fig.10 The structural flow chart of the composite patterned substrate shown;

[0048] Fig.12 It is a schematic diagram of the structure of an LED epitaxial wafer provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0050] Figure 1 is a schematic diagram of a wrapped patterned composite substrate provided by an embodiment of the present invention, with reference to Figure 1 The wrapped patterned composite substrate includes a substrate 10 and a plurality of composite patterned microstructures 20 formed on the substrate 10; the composite patterned microstructure 20 includes a central protruding microstructure 21 and a crater-like annular protruding microstructure 22, the bottom of the central protruding microstructure 21 is integrally connected to the substrate 10, and the crater-like protruding microstructure 22 is made of a heterogeneous material; the crater-like annular protruding microstructure 22 is arranged around the central protruding microstructure 21, and wraps the bottom of the central protruding microstructure 21, exposing the top of the central protruding microstructure 21.

[0051] Among them, the upper surface of the wrapped patterned composite substrate is used to grow the epitaxial layer, and the epitaxial material will form a crystal nucleus on the flat C surface to grow into an epitaxial layer. The wrapped patterned composite substrate includes a substrate 10, and a composite patterned microstructure 20 is formed on the substrate 10. The composite patterned microstructure 20 can be used to reduce the area of ​​the flat C surface on the surface of the substrate 10, which can ensure the appropriate crystal nucleus density of the epitaxial material, reduce the stress during epitaxial growth, help reduce the defects generated during epitaxial growth, reduce the dislocation density, and ensure the quality of the epitaxial layer. At the same time, the composite patterned microstructure 20 includes a central protruding microstructure 21 and a crater-like annular protruding microstructure 22, wherein the crater-like annular protruding microstructure 22 is made of a heterogeneous material, which is essentially a material different from the substrate 10 and the epitaxial material relative to the substrate 10 and the epitaxial layer material such as gallium nitride. Generally, it is difficult for epitaxial materials to grow on this heterogeneous material, and the heterogeneous material has the effect of inhibiting the growth of epitaxial materials. At this time, the composite pattern microstructure 20 can not only reduce the flat C-surface area of ​​the substrate 10 surface from the morphology, but also inhibit the growth of epitaxial material thereon from the material perspective, thereby effectively reducing the stress during epitaxial growth and improving the growth quality of the epitaxial material.

[0052] The refractive index of the heterogeneous material can be set lower or higher than the refractive index of the substrate. Of course, the refractive index of the heterogeneous material mainly depends on the packaging structure used by the LED chip, which includes an upright structure and an inverted structure. When the refractive index of the heterogeneous material is lower than that of the substrate, the refractive index difference at the interface between the substrate and the epitaxial layer can be increased, so that the light incident from the epitaxial layer to the microstructure has a higher light reflectivity due to the larger refractive index difference at the interface, thereby improving the light reflection at the interface between the epitaxial layer and the substrate, so that the light is emitted from the substrate toward the epitaxial layer; when the refractive index of the heterogeneous material is higher than that of the substrate, the refractive index difference at the interface between the substrate and the epitaxial layer can be reduced, and the light refractive index is increased, thereby improving the transmission of light from the substrate, so that more light is transmitted and emitted from the substrate. In summary, by setting a heterogeneous microstructure, the light emission efficiency can be improved, thereby improving the light extraction efficiency of the LED chip.

[0053] In addition, it should be noted that the composite graphic microstructure 20 is arranged with a crater-like annular protrusion microstructure 22 around the central protrusion microstructure 21, and the crater-like annular protrusion microstructure 22 wraps the bottom of the central protrusion microstructure 21, exposing the top of the central protrusion microstructure 21, wherein the bottom of the central protrusion microstructure 21 and the base substrate 10 are an integral structure, that is, the material of the bottom of the central protrusion microstructure 21 is consistent with the material of the base substrate 10. At this time, the crater-like annular protrusion microstructure 22 and the central protrusion microstructure 21 will form a refractive index difference interface in the form of an inclined surface at the bottom of the central protrusion microstructure 21, and at the same time, the crater-like annular protrusion microstructure 22 and the base substrate 10 will also form a horizontal refractive index difference interface. Compared with a horizontal refractive index difference interface, a refractive index difference interface with a certain inclination angle can be more conducive to changing the transmission path of light and improving the probability of light emission. The surfaces of the two composite raised microstructures, especially the sides, can increase the interface between the epitaxial layer and the substrate, that is, produce more light reflection surfaces, which helps to make the light be reflected at more angles, increase the probability of light escaping from the LED chip, and improve the light output efficiency of the LED chip.

[0054] Based on the same inventive concept, an embodiment of the present invention further provides a method for preparing a wrapped patterned composite substrate, so as to prepare the wrapped patterned composite substrate as above. Figure 2 is a flow chart of a method for preparing a wrapped patterned composite substrate provided by an embodiment of the present invention. Figure 3 yes Figure 2 The structural flow chart of the wrapped graphic composite substrate shown in FIG. Figure 1-Figure 3 The method for preparing the wrapped patterned composite substrate comprises:

[0055] S110, providing a substrate, and patterning a central protruding microstructure on the substrate;

[0056] This step is essentially a process of preparing a central protruding microstructure 21 using the base substrate 10. Obviously, at this time, the bottom of the central protruding microstructure 21 is integrally connected to the base substrate 10. The central protruding microstructure 21 and the base substrate 10 are made of the same material and have the same refractive index.

[0057] S120, forming a heterogeneous material layer on the substrate;

[0058] This step is a process of depositing a heterogeneous material on the substrate 10. The heterogeneous material can be prepared by chemical vapor deposition, physical vapor deposition, magnetron sputtering, etc. The thickness of the heterogeneous material layer 30 can exceed the height of the central protruding microstructure 21, that is, completely cover the central protruding microstructure 21, or not exceed the height of the central protruding microstructure 21, exposing the top of the central protruding microstructure 21, which is not limited here.

[0059] S130, the patterned heterogeneous material layer forms a crater-like annular protrusion microstructure; wherein the crater-like annular protrusion microstructure is arranged around the central protrusion microstructure and wraps the bottom of the central protrusion microstructure, exposing the top of the central protrusion microstructure.

[0060] The process of patterning the heterogeneous material layer 30 in this step is essentially a process of etching the surface of the heterogeneous material layer 30 to form a microstructure. Obviously, in the process of etching the heterogeneous material layer 30 into a microstructure through an etching process, it is necessary to reasonably set the etching mask pattern according to the target microstructure shape, so as to transfer the mask pattern to the heterogeneous material layer 30.

[0061] The wrapped patterned composite substrate, preparation method and LED epitaxial wafer provided by the embodiment of the present invention are provided with a substrate substrate and a plurality of composite patterned microstructures formed on the substrate substrate, wherein the composite patterned microstructure includes a central protruding microstructure and a crater-like annular protruding microstructure, the bottom of the central protruding microstructure is integrally connected with the substrate substrate, the crater-like annular microstructure is made of heterogeneous materials, the crater-like annular protruding microstructure is arranged around the central protruding microstructure, and includes the bottom of the central protruding microstructure, exposing the top of the central protruding microstructure, which can solve the problem that the C surface of the existing patterned composite substrate has defects and the light emission efficiency is low, and increase the interface area and the inclination angle of the composite patterned microstructure with a refractive index difference, so as to change the transmission path of the light and improve the light emission probability. In addition, the wrapped patterned composite substrate with a composite patterned microstructure can reduce the dislocation density of the epitaxial material during epitaxial growth and improve the crystallization quality of the epitaxial material.

[0062] like Figure 1 In the composite pattern microstructure shown, the height H1 of the central protruding microstructure can be set to be consistent with the height H2 of the crater-like protruding microstructure. Figure 4 is a schematic diagram of the structure of another wrapped patterned composite substrate provided by an embodiment of the present invention, with reference to Figure 4 In another embodiment of the present invention, optionally, the height H1 of the central protruding microstructure 21 can be set to be greater than the height H2 of the crater-like protruding microstructure 22. The height of the central protruding microstructure 21 is comparable to the height of the crater-like protruding microstructure 22, that is, the heights of the two microstructures are kept at the same order of magnitude. At this time, the plane formed by the crater-like protruding microstructure 22 and the central protruding microstructure 21 is relatively gentle, so when forming the epitaxial layer, the epitaxial material can better form crystals, which is conducive to the growth of the epitaxial material and improves the epitaxial quality.

[0063] Figure 5 yes Figure 1 The top view of the wrapped patterned composite substrate shown in FIG. Figure 1 and Figure 5Optionally, an exposed base substrate 10 may be provided between two adjacent composite graphic microstructures 20. In other words, the center distance between any two composite graphic microstructures 20 provided on the base substrate 10 is greater than the bottom diameter or the maximum bottom length of the two composite graphic microstructures 20. At this time, there is still an exposed base substrate 10 between the two adjacent composite graphic microstructures 20, that is, there is a flat C-surface for the growth of epitaxial material, thereby ensuring the growth of epitaxial material. Of course, those skilled in the art may consider whether to provide an exposed base substrate 10 between two composite graphic microstructures 20 according to the different types of heterogeneous materials and substrate materials and the growth effect of epitaxial materials, and no excessive restrictions are imposed here.

[0064] Specifically, for the composite graphic microstructure in the above-mentioned wrapped graphic composite substrate, the embodiment of the present invention provides a variety of microstructure shapes. Optionally, in the composite graphic microstructure, the central protruding microstructure can be set as any one of a table-shaped microstructure, a columnar microstructure, a cone-shaped microstructure, a table-like microstructure and a cone-like microstructure. Similarly, optionally, the crater-like annular protruding microstructure can also be set to have an arc-shaped sidewall.

[0065] In addition, in the above embodiments, the preparation material of the substrate may include sapphire, silicon, silicon carbide, gallium nitride, silicon nitride, zinc oxide and spinel; the heterogeneous material may include oxides, nitrides, carbides and single substances. Specifically, the oxide can be SiOx, ZnO, TiOx, TaOx, HfO2, ZrOx, AlOx, GaOx, MgOx, BaOx, InOx, SnO2, LiOx, CaOx, CuOx, IrOx, RhOx, CdGeO, InGaZnO, ZnRhO, GaIn2O4, LaO, LaCuO, etc.; the nitride can be SiC, HfC, ZrC, WC, TiC, CrC, etc.; the carbide can be SiC, HfC, ZrC, WC, TiC, CrC, etc.; the single substance can be diamond, Si, Mo, Cu, Fe, Ag, Wu, Ni, Al, etc., and those skilled in the art can select and set the materials of the substrate and the composite graphic microstructure according to actual preparation requirements, without making too many restrictions here.

[0066] Continue to refer Figure 1-Figure 3It should be noted that, since the preparation process of the crater-like annular protrusion microstructure 22 is to perform patterning on the heterogeneous material layer 30, that is, the heterogeneous material layer 30 is formed into an annular protrusion through an etching step, and in this step, the top of the central protrusion microstructure 21 needs to be exposed at the same time, so during the etching process, the heterogeneous material layer 30 that wraps or covers the top of the central protrusion microstructure 21 will be etched away at the same time, and the central protrusion microstructure 21 will be etched at the same time in this process, so that the side wall slope of the top of the central protrusion microstructure 21 is slightly smaller than the side wall slope of the bottom. Figure 6 yes Figure 1 The enlarged partial view of the wrapped patterned composite substrate shown in FIG. Figure 6 In the above-mentioned wrapped patterned composite substrate, the central protruding microstructure 21 may specifically include an upper portion 211 and a lower portion 212 , and the sidewall inclination angle α of the upper portion 211 is smaller than the sidewall inclination angle β of the lower portion 212 .

[0067] Of course, considering that the specific preparation process will affect the shape and composition of the microstructure, in the above-mentioned step S120, the thickness of the heterogeneous material layer can be set to be greater than the height of the central protruding microstructure, and in the specific step S130 graphics process, the etching intensity of the heterogeneous material layer above the central protruding microstructure can be appropriately reduced, that is, a portion of the heterogeneous material is retained so that the heterogeneous material and the protruding microstructure below constitute the final central protruding microstructure. Figure 7 is a partially enlarged schematic diagram of another wrapped patterned composite substrate provided by an embodiment of the present invention, referring to Figure 7 Optionally, the central protruding microstructure 21 includes an upper portion 211, a middle portion 213 and a lower portion 212, the upper portion 211 is made of a heterogeneous material, and the lower portion 212, the middle portion 213 and the substrate 10 are integrally connected. In particular, since the heterogeneous material in the middle position is etched when the crater-like annular microstructure 22 is formed, a part of the central protruding microstructure 21 is also etched, so that the sidewall slope of the middle portion 213 of the central protruding microstructure 21 is smaller than the sidewall slope of the lower portion 212, and the shape presents two parts, the middle portion and the lower portion.

[0068] With respect to the specific structure of the composite patterned substrate provided in the above embodiment, the embodiment of the present invention also provides a specific preparation method. Figure 8 is a flow chart of another method for preparing a composite patterned substrate provided by an embodiment of the present invention. Fig. 9 yes Figure 8 The structural flow chart of the composite patterned substrate shown in FIG. Figure 8 and Fig. 9 , the preparation method of the composite patterned substrate comprises:

[0069] S111, forming a first photoresist layer on the substrate;

[0070] refer to Fig. 9 In the figure a), the first photoresist layer 41 can be formed by a positive photoresist or a negative photoresist. Correspondingly, in the process of etching to realize patterned transfer, it is necessary to reasonably set the exposure pattern to form a mask. The first photoresist layer 41 can be formed by a coating process such as a spin coating process, a spray coating process, a spin spray process, or a magnetron sputtering process or a plasma enhanced chemical vapor deposition process, which is not limited here.

[0071] S112, patterning the first photoresist layer to form a first photoresist column mask;

[0072] refer to Fig. 9 b), the process is essentially a process of exposing and developing the first photoresist layer 41. During exposure, a part of the first photoresist layer 41 is modified, and the modified area or the unmodified area can be removed by the developer, thereby retaining the exposed pattern on the first photoresist layer 41. It should be noted that the photoresist pattern retained in this process has multiple photoresist columns, thereby forming a first column mask 51.

[0073] S113, etching the substrate according to the first glue column mask to form a central protruding microstructure;

[0074] refer to Fig. 9 As shown in Figure c), it should be noted that after the central raised microstructure 21 is formed in this step, the first glue column mask 51 is still attached thereto. In order to remove the first glue column mask 51 and ensure the cleanliness of the substrate, it is necessary to remove the first glue column mask 51 and clean and dry the semi-finished substrate for use in subsequent steps.

[0075] S120, forming a heterogeneous material layer on the substrate;

[0076] S131, forming a second photoresist layer on the heterogeneous material layer;

[0077] refer to Fig. 9 Similarly, the second photoresist layer 42 of this step may also be made of positive or negative photoresist, and the coating process may also be spin coating or spray coating, or may be formed by magnetron sputtering or plasma enhanced chemical vapor deposition, which is also not limited here.

[0078] S132, patterning the second photoresist layer to form a second photoresist column mask;

[0079] refer to Fig. 9 As shown in FIG. f), the second glue column mask also has a glue column structure, and its mask pattern is mainly composed of a circular strip-shaped glue column and a glue column body at the center of the corresponding central protruding microstructure 21.

[0080] S133. According to the second glue column mask, the heterogeneous material layer is etched at least once to form a crater-like annular protruding microstructure; wherein the crater-like annular protruding microstructure is arranged around the central protruding microstructure and wraps the bottom of the central protruding microstructure to expose the top of the central protruding microstructure.

[0081] refer to Fig. 9 g), this step mainly uses the second glue column mask 52 to etch the heterogeneous material layer 30 in a large scale, and the etched structure basically ensures the shape of the crater-like annular protrusion microstructure. This etching process can be called main etching, which can include at least one main etching, so as to etch the thicker heterogeneous material layer to form a microstructure pattern. The specific implementation can include using plasma dry etching technology to perform multiple dry main etchings on the second glue column mask 52, the heterogeneous material layer 30 and the base substrate 10.

[0082] S134. Over-etching the crater-like annular protrusion microstructure to modify the graphic morphology of the crater-like annular protrusion microstructure and the central protrusion microstructure.

[0083] Optionally, in this step, the graphic morphology of the central protruding microstructure and the crater-like annular protruding microstructure formed in step S133 can be modified by appropriate over-etching to ensure that the two protruding microstructures meet the requirements of size and graphic shape.

[0084] After the microstructure is finally prepared, in order to ensure the cleanliness of the substrate, the composite patterned substrate needs to be cleaned, which is not only used to remove the excess material left by the second glue column mask 52, but also to clean the impurities on the surface of the substrate.

[0085] Corresponding to Figure 1 The wrapped patterned composite substrate shown in the figure, in the above step S133, may specifically include:

[0086] S1331. Perform at least one main etching on the heterogeneous material layer according to the second glue column mask, and etch the central protruding microstructure at the same time; wherein the central protruding microstructure includes an upper part and a lower part, and the inclination angle of the side wall of the upper part is smaller than the inclination angle of the side wall of the lower part.

[0087] Similarly, corresponding to Figure 7 The wrapped patterned composite substrate shown in the figure, the embodiment of the present invention also provides a specific method for preparing the wrapped patterned composite substrate. Fig.10 is a flow chart of another method for preparing a composite patterned substrate provided by an embodiment of the present invention. Fig.11 yes Fig.10 The structural flow chart of the composite graphic substrate shown in FIG.

[0088] S111, forming a first photoresist layer on the substrate;

[0089] S112, patterning the first photoresist layer to form a first photoresist column mask;

[0090] S120, forming a heterogeneous material layer on the substrate, wherein the thickness of the heterogeneous material layer is greater than the height of the central protruding microstructure;

[0091] S131, forming a second photoresist layer on the heterogeneous material layer;

[0092] S132, patterning the second photoresist layer to form a second photoresist column mask;

[0093] S1332, according to the second glue column mask, perform at least one main etching on the heterogeneous material layer, and etch the central protruding microstructure at the same time; wherein the crater-like annular protruding microstructure is arranged around the central protruding microstructure, and wraps the bottom of the central protruding microstructure, exposing the top of the central protruding microstructure; the central protruding microstructure includes an upper part, a middle part and a lower part, the upper part is made of heterogeneous material, and the lower part, the middle part and the substrate are integrally connected;

[0094] S134. Over-etching the crater-like annular protrusion microstructure to modify the graphic morphology of the crater-like annular protrusion microstructure and the central protrusion microstructure.

[0095] The embodiment of the present invention further provides an LED epitaxial wafer, Fig.12 is a schematic diagram of the structure of an LED epitaxial wafer provided by an embodiment of the present invention, with reference to Fig.12 The LED epitaxial wafer includes any one of the wrapped patterned composite substrates 100 provided in the embodiments of the present invention and an epitaxial layer 200 formed on the wrapped patterned composite substrate 100 .

[0096] Different LED epitaxial wafer growth technologies are required for forming epitaxial layers on heterogeneous microstructures of different materials, and for the patterned composite substrate provided in the embodiment of the present invention, the epitaxial layer 200 on the LED epitaxial wafer can be a GaN, AlGaN epitaxial layer, etc. Since the LED epitaxial wafer adopts the wrapped patterned composite substrate 100 provided in the above embodiment, it has the same beneficial effects as the wrapped patterned composite substrate 100.

[0097] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A wrapped patterned composite substrate, characterized in that: It includes a base substrate and a plurality of composite graphic microstructures formed on the base substrate; The composite graphic microstructure includes a central protruding microstructure and a crater-like annular protruding microstructure, the bottom of the central protruding microstructure is integrally connected to the substrate, and the crater-like protruding microstructure is made of a heterogeneous material; The crater-like annular protrusion microstructure is arranged around the central protrusion microstructure and wraps the bottom of the central protrusion microstructure, exposing the top of the central protrusion microstructure; The height of the central protruding microstructure is greater than or equal to the height of the crater-like protruding microstructure.

2. The wrapped patterned composite substrate according to claim 1, characterized in that: The base substrate is exposed between two adjacent composite pattern microstructures.

3. The wrapped patterned composite substrate according to claim 1, characterized in that: The central protruding microstructure is any one of a terrace-shaped microstructure, a columnar microstructure, a cone-shaped microstructure and a cone-like microstructure.

4. The wrapped patterned composite substrate according to claim 1, characterized in that: The central protruding microstructure includes an upper portion and a lower portion, and the inclination angle of the sidewall of the upper portion is smaller than the inclination angle of the sidewall of the lower portion.

5. The wrapped patterned composite substrate according to claim 1, characterized in that: The central raised microstructure comprises an upper part, a middle part and a lower part, the upper part is made of a heterogeneous material, and the lower part, the middle part and the substrate are integrally connected.

6. The wrapped patterned composite substrate according to claim 1, characterized in that: The side wall of the crater-like annular protrusion microstructure is arc-shaped.

7. The wrapped patterned composite substrate according to claim 1, characterized in that: The preparation materials of the substrate include sapphire, silicon, silicon carbide, gallium nitride, silicon nitride, zinc oxide and spinel; the heterogeneous materials include oxides, nitrides, carbides and single substances.

8. An LED epitaxial wafer, characterized in that: It comprises the wrapped patterned composite substrate as described in any one of claims 1 to 7.

9. A method for preparing a wrapped patterned composite substrate, characterized in that: For preparing the wrapped patterned composite substrate according to any one of claims 1 to 7, the preparation method comprising: Providing a substrate, and patterning a central protruding microstructure on the substrate; forming a heterogeneous material layer on the substrate; The heterogeneous material layer is patterned to form a crater-like annular protrusion microstructure; wherein the crater-like annular protrusion microstructure is arranged around the central protrusion microstructure and wraps the bottom of the central protrusion microstructure to expose the top of the central protrusion microstructure; the height of the central protrusion microstructure is greater than or equal to the height of the crater-like protrusion microstructure.

10. The method for preparing a wrapped patterned composite substrate according to claim 9, characterized in that: A substrate is provided, and a central protruding microstructure is patterned on the substrate, comprising: forming a first photoresist layer on the substrate; Patterning the first photoresist layer to form a first photoresist column mask; The base substrate is etched according to the first glue column mask to form the central protruding microstructure.

11. The method for preparing a wrapped patterned composite substrate according to claim 9, characterized in that: The heterogeneous material layer is patterned to form a crater-like annular protrusion microstructure, comprising: forming a second photoresist layer on the heterogeneous material layer; Patterning the second photoresist layer to form a second photoresist column mask; According to the second glue column mask, the heterogeneous material layer is subjected to at least one main etching, and the crater-like annular protruding microstructure is formed.

12. The method for preparing a wrapped patterned composite substrate according to claim 11, characterized in that: Also includes: The crater-like annular protrusion microstructure is over-etched to modify the graphic morphology of the crater-like annular protrusion microstructure and the central protrusion microstructure.

13. The method for preparing a wrapped patterned composite substrate according to claim 11, characterized in that: include: According to the second glue column mask, the heterogeneous material layer is mainly etched at least once, and the central protruding microstructure is etched at the same time; wherein the central protruding microstructure includes an upper part and a lower part, and the sidewall inclination angle of the upper part is smaller than the sidewall inclination angle of the lower part.

14. The method for preparing a wrapped patterned composite substrate according to claim 11, characterized in that: The thickness of the heterogeneous material layer is greater than the height of the central protruding microstructure; According to the second glue column mask, the heterogeneous material layer is patterned to form the crater-like annular protrusion microstructure, including: According to the second glue column mask, the heterogeneous material layer is subjected to at least one main etching, and the central protruding microstructure is etched at the same time; wherein the central protruding microstructure includes an upper part, a middle part and a lower part, the upper part is made of a heterogeneous material, and the lower part, the middle part and the substrate are integrally connected.

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