Preparation method of patterned substrate and patterned substrate

Abstract

The embodiment of the invention discloses a preparation method of a patterned substrate and the patterned substrate. The preparation method comprises the following steps: preparing an aqueous solution of metal oxide particles, and immersing a sapphire plain film in the aqueous solution, so that the surface of the sapphire plain film and metal oxide in the aqueous solution are subjected to a solid-phase chemical reaction, and a reactant layer which is softer than the sapphire plain film in texture is formed on the surface of the sapphire plain film, and patterning the surface of one side, provided with the reactant layer, of the sapphire plain film to form a patterned substrate. According to the embodiment of the invention, the advanced surface treatment of the sapphire substrate is realized, and the reactant layer more suitable for subsequent etching can be generated on the surface through the solid-phase reaction with the specific metal oxide, so that the etching rate of the sapphire plain film can be improved, the difficulty of patterning the sapphire plain film is improved, and the production efficiency of the sapphire plain film is improved. Therefore, the etching uniformity is further ensured, a relatively large depth-to-width ratio can be realized, the uniformity of the thickness of the epitaxial layer is finally improved, and the consistency of the light-emitting wavelength is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of semiconductor material processing, and in particular to a method for preparing a patterned substrate and a patterned substrate. Background Art

[0002] As the trend of miniaturization of semiconductor devices continues to intensify, higher process requirements are placed on sapphire, one of the basic substrates. Although sapphire is widely used due to its excellent physical properties, its hard and stable crystal structure poses challenges to fine processing, especially when highly precise pattern transfer is required. Traditional etching technology often finds it difficult to simultaneously ensure sufficient etching rate and good surface smoothness, which in turn affects the performance of the final product. Summary of the invention

[0003] The present invention provides a method for preparing a patterned substrate and a patterned substrate, which achieves effective regulation of the surface properties of a sapphire substrate, can improve the etching efficiency and epitaxial uniformity of the sapphire substrate, thereby greatly simplifying the production process of complex patterns and helping to construct a composite structure with better performance.

[0004] In a first aspect, an embodiment of the present invention provides a method for preparing a patterned substrate, comprising:

[0005] preparing an aqueous solution of metal oxide particles;

[0006] Immersing the sapphire flat sheet in the aqueous solution so that the surface of the sapphire flat sheet reacts with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet; the reactant layer is softer than the sapphire flat sheet;

[0007] The surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned substrate.

[0008] Optionally, immersing the sapphire flat sheet in the aqueous solution so that a solid phase chemical reaction occurs between the surface of the sapphire flat sheet and the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet, comprising:

[0009] The sapphire flat sheet is immersed in the aqueous solution whose temperature is adjusted to a preset temperature range and maintained for a preset time, so that the surface of the sapphire flat sheet undergoes a solid phase chemical reaction with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet.

[0010] Optionally, immersing the sapphire flat sheet in the aqueous solution so that the surface of the sapphire flat sheet undergoes a solid phase chemical reaction with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet, further comprising:

[0011] The aqueous solution is stirred at a preset speed.

[0012] Optionally, before immersing the sapphire flat sheet in the aqueous solution whose temperature is adjusted to a preset temperature range and maintaining the aqueous solution for a preset time, the method further comprises:

[0013] The aqueous solution is adjusted to be alkaline.

[0014] Optionally, adjusting the aqueous solution to be alkaline comprises:

[0015] The pH value of the aqueous solution is adjusted to be in the range of 9 to 12.

[0016] Optionally, the preset temperature range is 60°C to 90°C; the preset time is 4h to 24h.

[0017] Optionally, the aqueous solution of metal oxide particles is prepared, comprising:

[0018] The aqueous solution is formed by configuring metal oxide particles with a particle size ranging from 50 nm to 70 nm in a manner such that the weight of the metal oxide particles and the volume of water meet a preset weight-to-volume ratio.

[0019] Optionally, the metal oxide is any one of silicon dioxide, magnesium oxide, cerium dioxide, iron oxide, and alpha-phase aluminum oxide.

[0020] Optionally, patterning a surface of the sapphire flat sheet having the reactant layer to form a patterned substrate comprises:

[0021] According to the first preset etching condition, the surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned composite substrate having a plurality of first microstructures on the surface; the material of the first microstructures is the reactant; or,

[0022] According to the second preset etching condition, the surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned composite substrate having a plurality of second microstructures on the surface; the second microstructure comprises an upper portion and a lower portion stacked up and down, the material of the upper portion is the reactant, and the material of the lower portion is sapphire; or,

[0023] According to the third preset etching condition, the surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned sapphire substrate having a plurality of third microstructures on the surface; the material of the first microstructure is sapphire.

[0024] In a second aspect, an embodiment of the present invention further provides a patterned substrate, which is prepared using any one of the patterned substrate preparation methods provided by the embodiments of the present invention.

[0025] The technical solution of the embodiment of the present invention is to first prepare an aqueous solution of metal oxide particles, and then immerse the sapphire flat sheet in the aqueous solution so that the surface of the sapphire flat sheet undergoes a solid-phase chemical reaction with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet, and finally pattern the surface of the side of the sapphire flat sheet with the reactant layer to form a patterned substrate, thereby achieving early surface treatment of the sapphire substrate. Through the solid-phase reaction with a specific metal oxide, a reactant layer that is more suitable for subsequent etching, such as a softer texture and a smoother surface, can be generated on the surface, thereby increasing the etching rate of the sapphire flat sheet, improving the difficulty of patterning the sapphire flat sheet, further ensuring the uniformity of etching, helping to achieve a larger aspect ratio, and ultimately improving the uniformity of the thickness of the epitaxial layer and the consistency of the light-emitting wavelength, thereby greatly simplifying the production process of complex patterns and helping to construct a composite structure with better performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of a method for preparing a patterned substrate provided by an embodiment of the present invention;

[0027] Figure 2 is a structural schematic diagram of a patterned substrate provided by an embodiment of the present invention;

[0028] Figure 3 is a schematic structural diagram of another patterned substrate provided by an embodiment of the present invention;

[0029] Figure 4 is a structural schematic diagram of another patterned substrate provided by an embodiment of the present invention;

[0030] Figure 5 is a flow chart of another method for preparing a patterned substrate provided by an embodiment of the present invention;

[0031] Figure 6 is an etching rate curve comparison diagram provided by an embodiment of the present invention;

[0032] Figure 7 It is a curve diagram of substrate pattern etching aspect ratio and epitaxial wavelength uniformity provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] 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.

[0034] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. It should be noted that the directional words such as "upper", "lower", "left", "right" and the like described in the embodiments of the present invention are described at the angles shown in the accompanying drawings and should not be understood as limitations on the embodiments of the present invention. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second", etc. are only used for descriptive purposes and do not represent any order, quantity or importance, but are only used to distinguish different components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0035] The term “including” and its variations used in the present invention are open inclusions, that is, “including but not limited to.” The term “based on” means “based at least in part on.” The term “one embodiment” means “at least one embodiment.”

[0036] It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish the corresponding contents, and are not used to limit the order or interdependence.

[0037] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0038] Figure 1 is a flow chart of a method for preparing a patterned substrate provided by an embodiment of the present invention, with reference to Figure 1 , the preparation method may include:

[0039] S110, preparing an aqueous solution of metal oxide particles.

[0040] The metal oxide particles refer to metal oxide powder or particles with a particle size below micrometers, so as to be easily mixed with water to form a uniformly mixed suspension. This step is mainly used for surface treatment of the subsequent sapphire flat sheet, which is a preparatory step.

[0041] S120, immersing the sapphire flat sheet in an aqueous solution so that a solid phase chemical reaction occurs between the surface of the sapphire flat sheet and the metal oxide in the aqueous solution, thereby forming a reactant layer on the surface of the sapphire flat sheet; the texture of the reactant layer is softer than that of the sapphire flat sheet.

[0042] This step and the previous step can be understood as the process of surface treatment of the sapphire substrate of the flat sheet before the patterning substrate is patterned, so as to facilitate patterning. The aqueous solution of metal oxide particles configured in step S110 is mainly used to soften the surface of the sapphire flat sheet. Specifically, when the sapphire flat sheet is immersed in the aqueous solution of metal oxide, the surface of the sapphire flat sheet can be fully contacted with the metal oxide particles of a size below micrometers, and the two undergo a solid-phase chemical reaction, and the generated reactants are attached to the surface of the sapphire flat sheet to form a reactant layer. In addition, since the surface of the sapphire flat sheet has a certain degree of roughness and unevenness, a smaller particle size can better fit and act on the tiny unevenness of the sapphire surface, so that the solid-phase reaction of the surface is more sufficient and the surface is more stable, thereby reducing the surface roughness and the depth of the damaged layer. In addition, a smaller particle size helps to form a more uniform reactant layer after the reaction, so that the reactant layer generated during the solid-phase reaction will be smoother than the surface of the sapphire flat sheet, which is very important for accurately controlling the etching depth and shape.

[0043] In addition, when a suitable metal oxide is used, the texture of the reactant layer can be made softer than that of the sapphire flat sheet. Exemplarily, the metal oxide can be silicon dioxide (SiO2), magnesium oxide (MgO), cerium dioxide (CeO2), iron oxide (Fe2O3), a-phase aluminum oxide (a-Al2O3), but is not limited thereto. Taking silicon dioxide as an example, the surface of the sapphire flat sheet will react with silicon dioxide in a solid phase, and a passivation layer with a hardness less than that of the single crystal sapphire substrate will be generated after the solid phase chemical reaction, that is, Al2O3 and SiO2 particles react in a solid phase to generate a softer and more adhesive aluminum silicate layer. In this process, silicon dioxide not only destroys the original surface microstructure of the sapphire flat sheet (i.e., weakening of the bond), but also because aluminum silicate reactants can be gradually deposited during the chemical reaction, and because aluminum silicate itself has a certain self-healing ability and a lower surface roughness, the surface of the reactant layer is smoother than the surface of the sapphire flat sheet, achieving the effect of improving the surface smoothness and consistency of the sapphire flat sheet.

[0044] It should be added that when the sapphire wafer is immersed in an aqueous solution, a part of it will undergo a hydration reaction with water to generate hydrated aluminum oxide AlO(OH) and Al(OH)3. The hydrated aluminum oxide can provide an appropriate amount of hydroxide as a catalyst for the solid-phase reaction, which to a certain extent ensures the efficiency of the solid-phase reaction between the metal oxide and the surface of the sapphire wafer.

[0045] S130, patterning the surface of one side of the sapphire flat sheet having the reactant layer to form a patterned substrate.

[0046] Those skilled in the art will know that the process of patterning in this step may specifically include coating, photolithography and inductively coupled plasma (ICP) etching, wherein coating refers to the process of coating a photoresist layer on the surface, photolithography refers to the process of preparing a photoresist layer into a photoresist column by exposure and development using a mask, and ICP etching refers to the process of etching the sapphire flat sheet and the reactant layer using the photoresist column as a mask. During the ICP etching process, the etching conditions such as electrode power, intracavity pressure, temperature, time, etc. can be reasonably set to regulate the pattern formed by etching. The patterned sapphire substrate is subsequently used to grow gallium nitride-based epitaxy to manufacture light emitting diode (LED) chips.

[0047] Based on the surface treatment of the sapphire flat sheet in the previous step, it can be seen that the sapphire flat sheet can have a smoother, more uniform and relatively softer surface. On this basis, in the process of patterning the surface, the soft surface products with moderate hardness can be easily removed, thereby improving the etching efficiency of the sapphire flat sheet. At the same time, the consistency of the patterned substrate surface formed after etching of the surface-treated sapphire flat sheet can also be improved.

[0048] The above technical scheme first prepares an aqueous solution of metal oxide particles, and then immerses the sapphire flat sheet in the aqueous solution so that the surface of the sapphire flat sheet undergoes a solid-phase chemical reaction with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet. Finally, the surface of one side of the sapphire flat sheet with the reactant layer is patterned to form a patterned substrate, thereby achieving early surface treatment of the sapphire substrate. Through the solid-phase reaction with a specific metal oxide, a reactant layer that is more suitable for subsequent etching, such as a softer texture and a smoother surface, can be generated on the surface. This can increase the etching rate of the sapphire flat sheet, improve the difficulty of patterning the sapphire flat sheet, further ensure the uniformity of etching, help achieve a larger aspect ratio, and ultimately improve the uniformity of the thickness of the epitaxial layer and enhance the consistency of the luminescent wavelength, thereby greatly simplifying the production process of complex patterns and helping to construct a composite structure with better performance.

[0049] In addition, since a reactant layer is generated on the surface of the sapphire flat sheet through a solid phase reaction, the reactant is generally a hydrophilic substance, such as aluminum silicate, which can increase the hydrophilicity of the surface of the sapphire flat sheet. Those skilled in the art will understand that in the process of patterning the surface of the sapphire flat sheet, it is necessary to coat a photoresist layer on its surface to form a photoresist mask, and the hydrophilic sapphire flat sheet improved by the reactant layer can make the photoresist after subsequent glue coating have stronger adhesion to the substrate surface, better stability, and better uniformity of the glue column, thereby ensuring better uniformity of subsequent etching. Moreover, the reactant layer can also play the role of a mask on the surface of the sapphire flat sheet, protect the surface of the sapphire plane during the etching process, reduce the damage to the non-target area of ​​the surface of the sapphire flat sheet during the etching process, reduce surface defects, and reduce growth stress during subsequent epitaxial deposition growth, which helps to improve the quality of the epitaxial layer.

[0050] On the basis of the above embodiment, the present invention further proposes a variant embodiment of the above embodiment. It should be noted that, in order to make the description concise, only the differences from the above embodiment are described in the variant embodiment.

[0051] Figure 2 is a schematic diagram of a structure of a patterned substrate provided by an embodiment of the present invention, with reference to Figure 2 In one embodiment, S130, a surface of a side of the sapphire flat sheet having a reactant layer is patterned to form a patterned substrate, which can be specifically refined as follows:

[0052] S131. According to a first preset etching condition, a surface of a side of the sapphire flat sheet having a reactant layer is patterned to form a patterned sapphire substrate having a plurality of first microstructures on the surface; the material of the first microstructures is sapphire.

[0053] like Figure 2 As shown, this step is a process of using the reactant layer as a mask to etch the reactant layer on the sapphire flat sheet to form a first microstructure 21 composed of sapphire. At this time, the patterned substrate is essentially composed of a sapphire base 10 and the first microstructure 21 integrally connected to the sapphire base 10, and the patterned substrate is essentially a patterned sapphire substrate.

[0054] Figure 3 is a schematic diagram of the structure of another patterned substrate provided by an embodiment of the present invention, referring to Figure 3 In another embodiment, S130, the surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned substrate, which can be specifically refined as follows:

[0055] S132. According to the second preset etching condition, the surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned composite substrate having a plurality of second microstructures on the surface; the second microstructure includes an upper portion and a lower portion stacked up and down, the material of the upper portion is the reactant, and the material of the lower portion is sapphire.

[0056] like Figure 3 As shown, this step is a process of simultaneously etching the reactant layer and the sapphire flat sheet to form a second microstructure 22 composed of reactants and sapphire. Specifically, during the etching process, using a photoresist mask, the reactant layer in the area between the patterns will be etched away to expose the surface of the sapphire, and then the surface of the sapphire will be etched, while the reactant layer and sapphire in the pattern area will remain to form the second microstructure 22, the upper part 221 of the second microstructure 22 is the reactant material, and the lower part 222 is the sapphire material. It can be seen that the patterned substrate is actually a patterned composite substrate.

[0057] Taking silicon dioxide as an example, the reactant is aluminum silicate, and the material of the upper part 221 is aluminum silicate. Since the refractive index of aluminum silicate is 1.56 and the refractive index of sapphire is 1.76-1.78, in the patterned composite substrate prepared by this step, the material of the upper part 221 is aluminum silicate, which can form a refractive index difference with the lower part 222. After subsequent epitaxy, the patterned composite substrate can also guide the light to exit through the gradually increasing refractive index change, which is helpful for light extraction and improves light extraction efficiency.

[0058] Figure 4 is a schematic diagram of the structure of another patterned substrate provided by an embodiment of the present invention, referring to Figure 4 In yet another embodiment, S130, patterning a surface of the sapphire flat sheet having the reactant layer to form a patterned substrate can be specifically refined as follows:

[0059] S133, according to the third preset etching condition, patterning the surface of one side of the sapphire flat sheet having the reactant layer to form a patterned composite substrate having a plurality of third microstructures on the surface; the material of the third microstructures is the reactant.

[0060] like Figure 4 As shown, this step is a process of etching the reactant layer on the sapphire flat sheet to form a third microstructure 23 composed of reactants. At this time, the patterned substrate is essentially composed of a sapphire substrate 10 and a third microstructure 23 of reactant material located on the sapphire substrate 10, and the patterned substrate is essentially a patterned composite substrate.

[0061] Similarly, taking silicon dioxide as the metal oxide and aluminum silicate as the reactant, the third microstructure 23 and the sapphire substrate 10 can also form a refractive index difference. After subsequent epitaxy, the patterned composite substrate can guide the light to exit through a gradually increasing refractive index change, which is helpful for light extraction and improves light extraction efficiency.

[0062] Those skilled in the art can understand that the etching conditions during the ICP etching process directly determine the morphology of the pattern formed on the patterned substrate. Therefore, in order to realize the above three different patterned substrates, those skilled in the art can specifically adjust the specific composition and morphology of the microstructure by changing the upper and lower electrode power, chamber pressure, temperature, time and other conditions during the ICP etching process, which is not limited here. In addition, in order to realize the above three different patterned substrates, in step S120, the thickness of the reactant layer can be controlled to be 0 to 2 μm by appropriately adjusting the reaction conditions, such as reaction time, reaction temperature, etc., thereby ensuring that the surface of the sapphire flat sheet has a reactant layer of sufficient thickness, and the etching process conditions are coordinated during etching to adjust the formation of the target shape and composition of the pattern, or, as a mask, effectively protect the surface of the sapphire substrate from damage.

[0063] In the above embodiment, S120, immersing the sapphire flat sheet in an aqueous solution so that the surface of the sapphire flat sheet undergoes a solid phase chemical reaction with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet; after the texture of the reactant layer is softer than that of the sapphire flat sheet, S130, patterning the surface of one side of the sapphire flat sheet having the reactant layer, before forming a patterned substrate, the following steps may be added:

[0064] S121, clean the sapphire flat sheet with the reactant layer formed thereon.

[0065] Specifically, in order to avoid residual metal oxide particles on the sapphire flat sheet and affect the etching in the subsequent patterning process, the sapphire flat sheet with the reactant layer formed thereon needs to be cleaned after being taken out from the aqueous solution. For example, it can be thoroughly rinsed with deionized water and then placed in an etching chamber for etching after being rinsed.

[0066] Figure 5 is a flow chart of another method for preparing a patterned substrate provided by an embodiment of the present invention, with reference to Figure 5 In order to optimize the solid phase reaction conditions, the present invention also provides a more detailed preparation method. Based on the above embodiment, for S110, an aqueous solution of metal oxide particles is prepared, which can be specifically refined as follows:

[0067] Metal oxide particles with a particle size ranging from 50 nm to 70 nm are configured to form an aqueous solution in a manner that the weight of the metal oxide particles and the volume of water meet a preset weight-to-volume ratio.

[0068] For S120, the sapphire flat sheet is immersed in an aqueous solution so that the surface of the sapphire flat sheet undergoes a solid phase chemical reaction with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet, which can be specifically broken down into:

[0069] The sapphire flat sheet is immersed in an aqueous solution whose temperature is adjusted to a preset temperature range and maintained for a preset time, so that the surface of the sapphire flat sheet and the metal oxide in the aqueous solution undergo a solid phase chemical reaction to form a reactant layer on the surface of the sapphire flat sheet.

[0070] Further optionally, before immersing the sapphire flat sheet in the aqueous solution whose temperature is adjusted to a preset temperature range and maintaining the aqueous solution for a preset time, the following steps may be further provided:

[0071] Adjust the aqueous solution to be alkaline.

[0072] Further optionally, with respect to S120, immersing the sapphire flat sheet in an aqueous solution so that the surface of the sapphire flat sheet reacts with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet, the following steps may also be provided:

[0073] The aqueous solution is stirred at a preset speed.

[0074] For details not yet provided in this embodiment, please refer to the previous embodiment.

[0075] like Figure 5 As shown, the method for preparing a patterned substrate provided in the second embodiment of the present invention comprises the following steps:

[0076] S210, using metal oxide particles with a particle size ranging from 50 nm to 70 nm, and configuring an aqueous solution in such a way that the weight of the metal oxide particles and the volume of water meet a preset weight-to-volume ratio.

[0077] Among them, the particle size of the metal oxide particles determines the probability of contact with the surface of the sapphire flat sheet to a certain extent, and thus affects the ability of the metal oxide and the surface of the sapphire flat sheet to undergo solid-phase chemical reaction. In this embodiment, the particle size range of the metal oxide particles is set to 50nm~70nm, which can ensure that the solid-phase reaction is more sufficient and the surface is more stable. The metal oxide and the surface of the sapphire flat sheet can undergo solid-phase reaction at an appropriate rate, which is convenient for controlling the reaction process and generating a more uniform and consistent reactant layer of suitable thickness on the surface of the sapphire flat sheet.

[0078] The ratio of the weight of the metal oxide particles to the volume of water can characterize the concentration of the metal oxide particles in the aqueous solution, which also affects the ability of the metal oxide and the sapphire flat plate surface to undergo solid-phase chemical reactions. Therefore, in this embodiment, the aqueous solution can be configured according to a preset weight-to-volume ratio to facilitate control of the solid-phase reaction rate and the thickness and surface consistency of the reactant layer. The specific weight-to-volume ratio is not limited here, and those skilled in the art can obtain it through experiments according to actual needs.

[0079] S221. Adjust the aqueous solution to be alkaline.

[0080] Adjusting the aqueous solution to alkaline means that the aqueous solution contains hydroxide ions. For the solid-phase reaction of metal oxide particles and sapphire flat sheets, hydroxide ions can participate in the reaction as a catalyst, or help dissolve certain components, thereby accelerating the reaction process and reducing the reaction time. In addition, alkaline conditions are conducive to the formation of soft material structures with a high degree of cross-linking, making the reactant layer softer, smoother, and more consistent. Specifically, the pH value of the aqueous solution can be adjusted to a range of 9 to 12, so that the aqueous solution has a suitable concentration of hydroxide ions, providing a suitable gain effect for the solid-phase reaction of metal oxide particles and sapphire flat sheets, so that the reactant layer achieves the optimal texture and morphology.

[0081] S222, immersing the sapphire flat sheet in an aqueous solution whose temperature is adjusted to a preset temperature range, and maintaining the solution for a preset time.

[0082] This step is also a step of using more optimized conditions to improve the solid phase reaction process of the metal oxide particles and the sapphire flat sheet, wherein a higher temperature can accelerate the reaction rate; a longer reaction time will generate more reactants, and a higher concentration of reactants will promote the deposition of more substances, thereby increasing the thickness of the reactant layer. Exemplarily, the preset temperature range can be set to 60°C to 90°C; the preset time is 4h to 24h, at which time, the metal oxide particles can have sufficient mixing time and mixing temperature with the sapphire flat sheet, undergo sufficient solid phase reaction, and generate a reactant layer of suitable thickness on the surface of the sapphire flat sheet.

[0083] S223, stirring the aqueous solution at a preset rotation speed so that the surface of the sapphire flat sheet and the metal oxide in the aqueous solution undergo a solid phase chemical reaction to form a reactant layer on the surface of the sapphire flat sheet.

[0084] Similarly, the flow rate of the liquid also affects the contact probability between the metal oxide particles and the sapphire flat sheet, that is, it affects the solid phase reaction rate between the metal oxide particles and the sapphire flat sheet. Therefore, in this embodiment, the water solution can be stirred by a preset rotation speed so that the metal oxide particles therein can fully contact and react with the surface of the sapphire flat sheet, thereby changing the transfer efficiency at the reaction interface and optimizing the growth rate and uniformity of the reactant layer. The specific rotation speed is not limited here, and those skilled in the art can obtain it through experiments according to actual needs.

[0085] S230, patterning a surface of the sapphire wafer having the reactant layer to form a patterned substrate.

[0086] In this embodiment, by optimizing various reaction conditions, including changing the pH value of the aqueous solution, setting appropriate temperature and time conditions, and adding stirring means, etc., the solid-phase reaction process of the metal oxide particles and the sapphire wafer is improved, and a softer and smoother reactant layer can be generated on the sapphire wafer more quickly and efficiently, thereby increasing the subsequent etching rate of the sapphire wafer and improving the difficulty of patterning the sapphire wafer.

[0087] Continue to refer Figure 2 to Figure 4 The embodiment of the present invention also provides a variety of patterned substrates, which are prepared by any one of the patterned substrate preparation methods provided in the embodiment of the present invention. It can be understood that since the patterned substrate is prepared by the patterned substrate preparation method of the above embodiment, it has the same or similar beneficial effects as the preparation method, which will not be repeated here.

[0088] In order to verify the feasibility and effect of the above embodiment, the present invention also conducted corresponding experiments, and the specific operation steps are illustrated as follows:

[0089] 1. Select SiO2 powder with an average diameter of about 50nm-70nm, add 20g SiO2 powder per liter of water, add it to deionized water, and stir evenly until a clear and transparent suspension is obtained;

[0090] 2. Place the sapphire substrate that has been preliminarily cleaned in a container containing the aforementioned suspension, close the lid, place it in a constant temperature box, heat it to 75°C, and let it stand for 12 hours;

[0091] 3. After the immersion process is completed, take out the workpiece immediately and quickly rinse off the remaining components with water;

[0092] 4. Finally, the sample is etched.

[0093] Figure 6: is an etching rate curve comparison diagram provided by an embodiment of the present invention, in which the horizontal axis is the electrode power during the etching process, in W, and the vertical axis is the etching rate, in nm / s. Figure 6 As shown, under different electrode powers, the etching rate of the sapphire substrate surface treated with a silica suspension is about 2nm / s, while the etching rate of the sapphire substrate that has not been surface treated is about 1nm / s. The experiment shows that the etching rate of the sapphire substrate surface treated with a silica suspension is significantly higher than that of the sapphire substrate that has not been surface treated, and the etching rate is doubled. In addition, after testing and verification, the results also show that the average etching depth of the sapphire substrate surface treated with a silica suspension increased by about 30%, and the surface roughness before and after treatment decreased by at least 20%. It can be seen that the method for preparing a patterned substrate provided by an embodiment of the present invention can significantly improve the etching rate in the patterning process, reduce the difficulty of etching, help to increase the depth-to-width ratio of the pattern, and show a higher etching rate and better morphology control ability when performing conventional ICP and other processes.

[0094] Figure 7 This is a graph of substrate pattern etching aspect ratio and epitaxial wavelength uniformity provided by an embodiment of the present invention. The ordinate in the graph is the pattern aspect ratio (H / W), and the abscissa is the STD value, which represents the standard deviation of the wavelength of the LED chip, that is, the ratio of the difference between the maximum value and the minimum value divided by the average value. The smaller the STD value, the better the wavelength consistency of the LED chip. Figure 7 It can be seen that the larger the aspect ratio (H / W) of the pattern, the smaller the STD value, that is, the higher the wavelength uniformity of the LED chip. It can be seen that the method for preparing a patterned substrate provided by the embodiment of the present invention can improve the aspect ratio of the pattern, thereby improving the uniformity of the wavelength after epitaxy, so that the final LED chip has higher wavelength consistency.

[0095] 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 method for preparing a patterned substrate, characterized in that: include: preparing an aqueous solution of metal oxide particles; Immersing the sapphire flat sheet in the aqueous solution so that the surface of the sapphire flat sheet reacts with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet; the reactant layer is softer than the sapphire flat sheet; The surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned substrate.

2. The preparation method according to claim 1, characterized in that: Immersing the sapphire flat sheet in the aqueous solution so that the surface of the sapphire flat sheet reacts with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet, comprising: The sapphire flat plate is immersed in the aqueous solution whose temperature is adjusted to a preset temperature range and maintained for a preset time.

3. The preparation method according to claim 2, characterized in that: The sapphire flat sheet is immersed in the aqueous solution so that the surface of the sapphire flat sheet reacts with the metal oxide in the aqueous solution to form a reactant layer on the surface of the sapphire flat sheet, and further comprises: The aqueous solution is stirred at a preset rotation speed so that a solid phase chemical reaction occurs between the surface of the sapphire flat plate and the metal oxide in the aqueous solution, thereby forming a reactant layer on the surface of the sapphire flat plate.

4. The preparation method according to claim 2, characterized in that: Before immersing the sapphire flat sheet in the aqueous solution whose temperature is adjusted to a preset temperature range and maintaining the solution for a preset time, the method further comprises: The aqueous solution is adjusted to be alkaline.

5. The preparation method according to claim 4, characterized in that: Adjusting the aqueous solution to be alkaline comprises: The pH value of the aqueous solution is adjusted to be in the range of 9 to 12.

6. The preparation method according to claim 2, characterized in that: The preset temperature range is 60°C to 90°C; the preset time is 4h to 24h.

7. The preparation method according to claim 1, characterized in that: An aqueous solution of metal oxide particles is prepared, comprising: The aqueous solution is formed by configuring metal oxide particles with a particle size ranging from 50 nm to 70 nm in a manner such that the weight of the metal oxide particles and the volume of water meet a preset weight-to-volume ratio.

8. The preparation method according to claim 1, characterized in that: The metal oxide is any one of silicon dioxide, magnesium oxide, cerium dioxide, iron oxide, and a-phase aluminum oxide.

9. The preparation method according to claim 1, characterized in that: Patterning a surface of the sapphire flat sheet having the reactant layer to form a patterned substrate includes: According to the first preset etching condition, the surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned sapphire substrate having a plurality of first microstructures on the surface; the material of the first microstructures is sapphire; or, According to the second preset etching condition, the surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned composite substrate having a plurality of second microstructures on the surface; the second microstructure comprises an upper portion and a lower portion stacked up and down, the material of the upper portion is the reactant, and the material of the lower portion is sapphire; or, According to the third preset etching condition, the surface of one side of the sapphire flat sheet having the reactant layer is patterned to form a patterned composite substrate having a plurality of third microstructures on the surface; the material of the third microstructures is sapphire reactant.

10. A patterned substrate, characterized in that: The patterned substrate is prepared by the method for preparing the patterned substrate as described in any one of claims 1 to 9.

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