Patterned composite substrate based on sponge protrusions and preparation method

Abstract

The invention discloses a patterned composite substrate based on sponge protrusions and a preparation method thereof. The patterned composite substrate comprises a sapphire substrate; the plurality of sponge bulge microstructures are positioned on one side of the sapphire substrate in the thickness direction; the sponge bulge microstructure comprises a sponge skeleton structure, the sponge skeleton structure is prepared from a silicon nitride material, and three-dimensional interpenetrating network pores are formed in the sponge skeleton structure. According to the technical scheme, the transverse stress of epitaxial growth can be buffered by using the conical shape, the porosity and elasticity characteristics can be realized by using the three-dimensional interpenetrating network pores, and a template is further provided for stress relaxation and defect annihilation in epitaxial growth, so that a low-stress and low-defect epitaxial material layer can be obtained, the crystal quality is improved, and the yield of the epitaxial material layer is improved. And meanwhile, the reflection probability of LED light rays can be improved through refractive index transition, so that the luminous efficiency is improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to LED patterning substrate technology, and particularly to a sponge protrusion-based patterned composite substrate and a preparation method thereof. BACKGROUND

[0002] GaN-based light-emitting diodes are commonly used light-emitting devices in the fields of solid-state lighting and semiconductor display. Heteroepitaxy technology is a mainstream technology for solving GaN thin film growth problems. In particular, a sub-micron protrusion array constructed on a periodic microstructure sapphire substrate surface formed by photolithography and dry etching can effectively suppress dislocation density and improve diode chip brightness.

[0003] In order to break through the physical limit of the traditional single-material substrate and improve the crystalline quality of the epitaxial material, the industry has developed a multi-material composite substrate technology. By optimizing the thermal expansion coefficient matching degree of the multi-material system, the residual stress of the epitaxial layer can be reduced, and the photon propagation path can be effectively controlled to convert the lateral mode into a vertical radiation mode. The composite substrate is developing towards multi-functional integration. However, how to further reduce the epitaxial stress to improve the GaN crystal quality and increase the escape probability of photons is still a key technical bottleneck that needs to be broken through in the current industry. SUMMARY

[0004] The present application provides a sponge protrusion-based patterned composite substrate and a preparation method thereof, which can more effectively relax stress, reduce lattice defects, and improve lattice quality during silicon nitride epitaxial layer growth, and can also improve the probability of LED light reflection, thereby improving the light efficiency.

[0005] In a first aspect, embodiments of the present application provide a sponge protrusion-based patterned composite substrate, comprising:

[0006] a sapphire substrate;

[0007] a plurality of sponge protrusion microstructures located on one side of the sapphire substrate in the thickness direction; the sponge protrusion microstructure comprises a sponge skeleton structure, the sponge skeleton structure is prepared from silicon nitride material, and the sponge skeleton structure has a three-dimensional interpenetrating network pore inside.

[0008] Optionally, the sponge protrusion microstructure further comprises a filling structure, the filling structure is filled in at least part of the pores inside the sponge skeleton structure, and the filling structure is prepared from silicon dioxide material.

[0009] Optionally, the sponge protrusion microstructure comprises a core structure and an outer shell structure, and the outer shell structure covers the core structure.

[0010] The sponge skeleton structure comprises a first part and a second part, the core structure comprises the first part and the filling structure filled in the pores inside the first part, and the shell structure comprises the second part.

[0011] Optionally, the height H3 of the sponge convex microstructure satisfies 1.8 μm ≤ H3 ≤ 3.5 μm.

[0012] Optionally, the porosity of the sponge skeleton structure satisfies 50% ≤ H4: H3 ≤ 80%.

[0013] Optionally, the height of the core structure is H4, the bottom diameter of the core structure is W3, the height of the sponge convex microstructure is H3, and the bottom diameter of the sponge convex microstructure is W2.

[0014] 50% ≤ H4: H3 ≤ 80%, and / or 50% ≤ W3: W2 ≤ 80%.

[0015] Optionally, the sponge convex microstructure further comprises a bonding layer between the sponge skeleton structure and the sapphire substrate, and the bonding layer is prepared from the silicon nitride material.

[0016] Optionally, the thickness H2 of the bonding layer satisfies 200 nm ≤ H2 ≤ 500 nm.

[0017] In a second aspect, the embodiments of the present application further provide a preparation method of a patterned composite substrate based on sponge convexes, comprising:

[0018] providing a sapphire substrate;

[0019] preparing a plurality of sponge convex microstructures on one side in the thickness direction of the sapphire substrate, wherein the sponge convex microstructure comprises a sponge skeleton structure prepared from a silicon nitride material, and has a three-dimensional interpenetrating network pore inside.

[0020] Optionally, the sponge convex microstructure further comprises a filling structure prepared from a silicon dioxide material.

[0021] preparing a plurality of sponge convex microstructures on one side in the thickness direction of the sapphire substrate, comprising:

[0022] alternately growing the silicon nitride material and the silicon dioxide material on one side in the thickness direction of the sapphire substrate to form a three-dimensional interpenetrating network structure layer;

[0023] ​Dry etching the three-dimensional interpenetrating network structure layer to form a plurality of the sponge convex microstructures, and the sponge convex structure is formed with the sponge skeleton structure and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0024] Optionally, on one side in the thickness direction of the sapphire substrate, the silicon nitride material and the silicon dioxide material are alternately grown in sequence to form a three-dimensional interpenetrating network structure layer, including alternately executed first pulse phase and second pulse phase;

[0025] The first pulse phase includes:

[0026] The three reaction gases of NH3, SiH4 and N2 are used, a first preset volume ratio is adopted, a first preset temperature range and a first preset reaction pressure range are adopted, a first pulse power is applied, a first preset time length is reacted, and a columnar β-Si3N4 crystal phase structure is grown.

[0027] The second pulse phase includes:

[0028] The three reaction gases of N2O, SiH4 and N2 are used, a second preset volume ratio is adopted, a second preset temperature range and a second preset reaction pressure range are adopted, a second pulse power is applied, a second preset time length is reacted, and amorphous SiO2 is grown in the gap of the columnar β-Si3N4 crystal phase structure.

[0029] Optionally, the first pulse phase and the second pulse phase are alternately executed repeatedly 12-30 times.

[0030] Optionally, the sponge convex microstructure includes a core structure and a shell structure, and the shell structure covers the core structure.

[0031] Dry etching the three-dimensional interpenetrating network structure layer to form a plurality of the sponge convex microstructures, and the sponge convex structure is formed with the sponge skeleton structure and a filling structure filled in at least part of the pores inside the sponge skeleton structure, including:

[0032] Dry etching the three-dimensional interpenetrating network structure layer to form a plurality of intermediate convex microstructures;

[0033] The sapphire substrate with a plurality of the intermediate convex microstructures is immersed in a hydrofluoric acid etching solution, and an ultrasonic wave is sent to the surface of the sapphire substrate with the intermediate convex microstructures in a preset frequency band, the filling structure of the surface layer of the intermediate convex microstructure is chemically corroded for a third preset time length, so that the sponge skeleton structure forms a first part and a second part, the first part and the filling structure filled in the pores inside the first part form the core structure, and the second part forms the shell structure.

[0034] Optionally, the sponge convex microstructure further comprises a bonding layer between the sponge skeleton structure and the sapphire substrate.

[0035] Before forming the three-dimensional interpenetrating network structure layer by alternately growing the silicon nitride material and the silicon dioxide material on one side of the sapphire substrate in the thickness direction of the sapphire substrate, further comprising:

[0036] An integral bonding layer is prepared on one side of the sapphire substrate in the thickness direction of the sapphire substrate by using the silicon nitride material.

[0037] The three-dimensional interpenetrating network structure layer is dry etched to form a plurality of sponge convex microstructures, and the sponge convex structure is formed with the sponge skeleton structure and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0038] The three-dimensional interpenetrating network structure layer and the integral bonding layer are dry etched to form a plurality of sponge convex microstructures, and the sponge convex structure is formed with the bonding layer, the sponge skeleton structure, and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0039] The present application provides a kind of based on sponge convex patterned composite substrate structure, utilize sapphire substrate as the substrate support of sponge convex microstructure, guarantee structure stable, again not block the propagation of light, the silicon nitride sponge skeleton structure of multiple sponge convex microstructure is located sapphire substrate surface side, it has three-dimensional interpenetrating network pore inside.This structure not only can utilize the lateral stress of tapered shape buffer epitaxial growth, also can realize loose, elastic characteristics by three-dimensional interpenetrating network pore, further for epitaxial growth in stress relaxation and defect annihilation provide template, so as to obtain low stress, low defect epitaxial material layer, improve crystal quality, simultaneously still can pass through refractive index transition, improve LED light reflection probability, so as to improve light efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 It is a kind of based on sponge convex patterned composite substrate structure schematic diagram provided in the embodiment of the present application;

[0041] Figure 2 It is another kind of based on sponge convex patterned composite substrate structure schematic diagram provided in the embodiment of the present application;

[0042] Figure 3 It is still another kind of based on sponge convex patterned composite substrate structure schematic diagram provided in the embodiment of the present application;

[0043] Figure 4is another schematic diagram of a patterned composite substrate based on sponge protrusions provided by an embodiment of the present application;

[0044] Figure 5 is another schematic diagram of a patterned composite substrate based on sponge protrusions provided by an embodiment of the present application;

[0045] Figure 6 is a flow chart of a method for preparing a patterned composite substrate based on sponge protrusions provided by an embodiment of the present application;

[0046] Figure 7 is Figure 6 a flow chart of a structure of a patterned composite substrate based on sponge protrusions;

[0047] Figure 8 is a flow chart of another method for preparing a patterned composite substrate based on sponge protrusions provided by an embodiment of the present application;

[0048] Figure 9 is a flow chart of yet another method for preparing a patterned composite substrate based on sponge protrusions provided by an embodiment of the present application;

[0049] Figure 10 is a flow chart of still another method for preparing a patterned composite substrate based on sponge protrusions provided by an embodiment of the present application;

[0050] Figure 11 is Figure 10 a flow chart of a structure of a patterned composite substrate based on sponge protrusions;

[0051] Figure 12 is a flow chart of still another method for preparing a patterned composite substrate based on sponge protrusions provided by an embodiment of the present application. DETAILED DESCRIPTION

[0052] The present application will be further described below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0053] The terms used in the embodiments of the present application are merely used for the purpose of describing particular embodiments and are not intended to limit the present application. It should be noted that the positional words such as "upper", "lower", "left", "right", and the like described in the embodiments of the present application are described in the angle shown in the drawings, and should not be understood as a limitation on the embodiments of the present application. In addition, it should be understood in the context that when referring to an element being formed "on" or "under" another element, it can be directly formed "on" or "under" another element, or indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second", and the like are only for the purpose of description and do not represent any order, quantity or importance, but are only used to distinguish different components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0054] The term "comprising" and its variants used in the present application are open and include "but not limited to". The term "based on" is "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0055] It should be noted that the concepts of "first", "second", and the like mentioned in the present application are only used to distinguish the corresponding content, and are not used to limit the order or mutual dependency.

[0056] It should be noted that the modification of "one" or "multiple" mentioned in the present application is illustrative and not limiting, and those skilled in the art should understand that unless otherwise explicitly indicated in the context, it should be understood as "one or more".

[0057] Figure 1 is a schematic diagram of a patterned composite substrate structure based on sponge protrusions provided by the embodiments of the present application, referring to Figure 1 A patterned composite substrate based on sponge protrusions includes: a sapphire substrate 10; a plurality of sponge protrusion microstructures 20 located on one side of the sapphire substrate 10 in the thickness direction; the sponge protrusion microstructure 20 includes a sponge skeleton structure 21, the sponge skeleton structure 21 is prepared from silicon nitride material, and the sponge skeleton structure 21 has a three-dimensional interpenetrating network pore inside.

[0058] The base refers to a bottom support material constituting the composite substrate, and provides hard and stable physical support for the convex structure on the surface, and the base material is selected from sapphire material because of its strong chemical inertness, high Mohs hardness, high wide-spectrum light transmittance and strong anti-radiation damage capability, which is the preferred base material for heteroepitaxy process. A plurality of sponge convex microstructures 20 are arranged on one side of the sapphire base 10 in the thickness direction, the sponge convex microstructures 20 are conical, and the sponge convex microstructures 20 include a sponge skeleton structure 21, the surface of which is similar to a sponge and is full of interconnected pores, which form a three-dimensional interpenetrating network pore similar to a honeycomb structure, which can be filled with air or other heterogeneous materials, and can be completely filled or partially filled. Thus, on the one hand, when the epitaxial material grows in the gaps of the sponge convex microstructures 20 of the composite substrate, the conical sponge convex microstructures 20 can release the stress of the epitaxial material in the lateral direction, and the sponge skeleton structure 21 which is not completely filled not only forms pores on the surface, but also can fill the pores to a certain extent when the epitaxial material grows, thereby releasing a certain growth stress. At the same time, due to the existence of the three-dimensional interpenetrating network pore, the sponge convex microstructure 20 has a loose property, that is, has a certain elasticity, so as to further buffer the stress of the epitaxial material during growth, provide an elastic template for stress relaxation and defect annihilation in the epitaxial material growth process, and is beneficial to obtain an epitaxial layer with low stress and low defects. In addition, the sponge skeleton structure 21 with pores can conveniently adjust the refractive index of the sponge convex microstructure 20 through porosity, so as to match the refractive index of the epitaxial layer grown thereon, reduce the total reflection of the light emitted by the light emitting diode, increase the light emission probability, and improve the light extraction efficiency.

[0059] The sponge convex patterned composite substrate structure provided by the present application uses a sapphire base as the substrate support of the sponge convex microstructure, ensures the stability of the structure, and does not block the propagation of light. The silicon nitride sponge skeleton structure of the plurality of sponge convex microstructures is located on one side of the surface of the sapphire base, and has a three-dimensional interpenetrating network pore inside. This structure not only can buffer the lateral stress of epitaxial growth by using the conical shape, but also can realize the loose and elastic properties by using the three-dimensional interpenetrating network pore, thereby providing a template for stress relaxation and defect annihilation in epitaxial growth, so as to obtain an epitaxial material layer with low stress and low defects, improve the crystal quality, and also can improve the light reflection probability of the LED by refractive index transition, thereby improving the light extraction efficiency.

[0060] Optionally, Figure 2 is another schematic view of the sponge convex patterned composite substrate structure provided by the embodiment of the present application, referring to Figure 2 The sponge convex microstructure 20 further includes a filling structure 22, which is filled in at least part of the pores inside the sponge skeleton structure 21, and the filling structure 22 is prepared from silica material.

[0061] The pores can be filled completely or partially, and the embodiments of the present application do not limit the same. The silicon nitride and the silicon dioxide form a composite pattern layer, the refractive index of the silicon nitride is about 1.9, the refractive index of the silicon dioxide is about 1.47, the difference between the refractive indexes of the two, combined with the air in the pores, forms an adjustable refractive index interval, and the light extraction efficiency is further improved through the total reflection effect of the interface. In addition, after the pores are filled with the silicon dioxide, the surface of the sponge convex microstructure 20 still has pores, which can further release the stress generated during epitaxial material growth, effectively inhibiting the dislocation density.

[0062] Optionally, Figure 3 is another schematic diagram of a patterned composite substrate structure based on a sponge convex provided by an embodiment of the present application, referring to Figure 3 The sponge convex microstructure 20 includes a core structure 23 and a shell structure 24, and the shell structure 24 covers the core structure 23; the sponge skeleton structure 21 includes a first part 211 and a second part 212, the core structure 23 includes the first part 211 and a filling structure 22 filled in the pores inside the first part 211, and the shell structure 24 includes the second part 212.

[0063] The sponge convex microstructure 20 is a convex unit of the surface of the composite substrate, includes the core structure 23 and the shell structure 24, and the shell structure 24 completely covers the core structure 23 from the outside, forming a nested layered structure. The sponge skeleton structure 21 includes two parts of the first part 211 and the second part 212, the first part 211 belongs to the skeleton base of the core structure 23 and has a three-dimensional interpenetrating network pore itself, and the second part 212 constitutes the skeleton main body of the shell structure 24 and also has a three-dimensional interpenetrating network pore. The core structure 23 is composed of the first part 211 of the silicon nitride skeleton structure and the filling structure 22, and the silicon dioxide can be filled as the filling structure 22 in the pores of the first part 211, and the shell structure 24 is composed of the second part 212 of the silicon nitride porous skeleton, and together with the core structure 23, forms the shape of the sponge convex microstructure 20. In this embodiment, by forming the shell structure 24 with pores, the sponge convex microstructure 20 can be wrapped with a loose and elastic shell, and the loose and elastic shell can relax the stress during epitaxial growth, reduce defects, and improve the crystal quality.

[0064] Optionally, the height H3 of the sponge convex microstructure 20 satisfies 1.8 μm≤H3≤3.5 μm.

[0065] It can be understood that the height of the sponge protrusion microstructure 20 can provide sufficient material growth space. If the height is less than 1.8 μm, the three-dimensional interpenetrating network pores of the sponge skeleton structure 21 cannot effectively absorb the lattice stress during epitaxial growth, resulting in an increase in the dislocation density of the GaN epitaxial layer, causing crystal defects, and leading to a decrease in the light-emitting efficiency. If the height is greater than 3.5 μm, the stability of the sponge protrusion microstructure 20 itself is reduced, resulting in the accumulation of residual stress, causing cracks and bending of the epitaxial layer, and destroying the integrity of the crystal. A suitable height can enable the sponge protrusion microstructure 20 to play a role in stress absorption, ensuring high light-emitting efficiency and high reliability of the LED chip.

[0066] Optionally, the porosity of the sponge skeleton structure 21 is 50% to 80%. satisfies:

[0067] It can be understood that the porosity of the sponge skeleton structure 21 determines the refractive index of the sponge protrusion microstructure 20. A suitable porosity can provide the sponge protrusion microstructure 20 with a specific refractive index, which can adapt to the needs of different product refractive indices.

[0068] Optionally, the height of the core structure 23 is H4, the bottom diameter of the core structure 23 is W3; the height of the sponge protrusion microstructure is H3, and the bottom diameter of the sponge protrusion microstructure is W2; wherein, 50%≤H4: H3≤80%; and / or, 50%≤W3: W2≤80%.

[0069] Firstly, the height and bottom diameter of the sponge protrusion microstructure 20 are actually also the height and bottom diameter of the shell structure 24. The embodiment limits the height ratio of the core structure 23 and the sponge protrusion microstructure 20 to satisfy the above numerical range, which is essentially to limit the height ratio of the core structure 23 and the shell structure 24 to satisfy the above numerical range. Similarly, limiting the bottom diameter ratio of the core structure 23 and the sponge protrusion microstructure 20 to satisfy the above numerical range is essentially to limit the bottom diameter ratio of the core structure 23 and the shell structure 24 to satisfy the above numerical range. In the embodiment, the height ratio and the bottom diameter ratio of the core structure 23 and the shell structure 24 are limited to satisfy the above numerical range, which on the one hand limits the thickness of the shell structure 24, so that the surface of the sponge protrusion microstructure 20 has enough pores to form a loose and elastic shell, thereby effectively releasing the lateral stress when epitaxial growth to the side of the sponge protrusion microstructure 20, and on the other hand, the refractive index of the sponge protrusion microstructure 20 can be adjusted to adapt to the needs of different product refractive indices, thereby improving the light-emitting effect.

[0070] Optionally, Figure 4 is another schematic diagram of a patterned composite substrate structure based on a sponge protrusion provided by the embodiment of the present application, which is referred to Figure 4The sponge convex microstructure 20 further comprises a bonding layer 25 located between the sponge skeleton structure 21 and the sapphire substrate 10, wherein the bonding layer 25 is made of silicon nitride.

[0071] The bonding layer 25 is located between the sponge skeleton structure 21 and the sapphire substrate 10, and the bonding layer 25 is made of silicon nitride. The refractive index of silicon nitride is about 1.9, which can create a refractive index difference between different materials, improve the probability of photon escape, and at the same time, because silicon nitride is not corroded by hydrofluoric acid, it can lay a solid foundation for the combination of the convex structure and the upper surface of the sapphire, so that the bonding force between the two is not destroyed by hydrofluoric acid, and the central core structure 23 and the outer core structure 24 are both made of silicon nitride as the skeleton material, making the connection of each part more stable, and strengthening the connection reliability of the whole sponge convex microstructure 20.

[0072] Optionally, the thickness H2 of the bonding layer 25 satisfies: 200nm≤H2≤500nm.

[0073] It can be understood that the thickness of the bonding layer 25 should be in a suitable range. If the thickness of the bonding layer 25 is too thin, the interface bonding force will be weak, and the sponge skeleton structure 21 will be easily peeled off from the sapphire surface during subsequent hydrofluoric acid cleaning, which has poor stability, and at the same time, it can lead to the reflection of photons back to the inside of the chip, reducing the escape probability. If the thickness of the bonding layer 25 is too thick, it will cause internal defects due to stress accumulation, which will reduce the light extraction efficiency of the LED chip. The suitable thickness of the bonding layer 25 can stably combine the sapphire substrate 10 and the sponge convex microstructure 20, and improve the stability of the composite substrate.

[0074] Optionally, Figure 5 is another sponge convex based patterned composite substrate structure provided by the embodiment of the present application, which refers to Figure 5 The sponge convex microstructure 20 further comprises a sapphire layer 26, which is integrally connected with the sapphire substrate 10, and the sponge skeleton structure 21 is located on the side of the sapphire layer 26 away from the sapphire substrate 10.

[0075] When the sponge convex microstructure 20 is prepared by dry etching, it is necessary to a certain extent to destroy part of the sapphire substrate 10 area by over-etching, so that the covered sapphire substrate is exposed, thereby ensuring that the epitaxial material grows on the exposed sapphire substrate surface.

[0076] Optionally, the thickness H1 of the sapphire layer 26 satisfies: H1≥150nm.

[0077] It can be understood that a sapphire layer 26 thick enough can ensure that the hetero film layer at each site on the upper surface of the substrate is etched through the sapphire layer 26 and the C face of the sapphire is exposed, avoiding epitaxial failure and causing fogging.

[0078] Optionally, the plurality of sponge protrusion microstructures 20 are arranged periodically, and the arrangement period T of the sponge protrusion microstructures 20 satisfies: 2.0 μm≤T≤5.0 μm; and / or the gap D between adjacent sponge protrusion microstructures 20 satisfies: D≥0.2 μm.

[0079] The periodic arrangement of multiple sponge protrusion microstructures 20 creates an orderly light-scattering array on the chip surface. Too small a period can lead to excessive light scattering and absorption due to the dense structure; too large a period can reduce light extraction efficiency. Furthermore, a gap of at least 0.2 μm prevents adhesion between the sponge protrusion microstructures 20, resulting in total reflection at the interface. This improves light extraction efficiency and provides a complete C-plane space for subsequent GaN epitaxial crystallization.

[0080] Figure 6 A flow chart of a method for preparing a patterned composite substrate based on sponge protrusions provided by an embodiment of the present invention, Figure 7 yes Figure 6 The structural flow chart of the graphic composite substrate based on sponge protrusions is shown in FIG. Figure 6 and Figure 7 , a method for preparing a patterned composite substrate based on sponge protrusions includes:

[0081] S110 , providing a sapphire substrate.

[0082] refer to Figure 7 (a) of FIG. , this step utilizes the characteristics of sapphire, such as strong chemical inertness, high Mohs hardness, high wide-spectrum transmittance and strong resistance to radiation damage, to select sapphire as the preferred base material for preparing the composite substrate.

[0083] S120. Prepare a plurality of sponge protrusion microstructures on one side of the sapphire substrate in the thickness direction.

[0084] The surface of the multiple sponge protrusion microstructures 20 resembles a sponge, covered in interconnected pores. These pores form a three-dimensional interpenetrating network similar to a honeycomb structure. This pore structure allows the cone-shaped sponge protrusion microstructures 20 to effectively buffer the stress generated during lateral growth during epitaxial growth of the underlying material, facilitating the production of low-stress, low-defect epitaxial materials. The sponge skeleton structure 21 is made of silicon nitride, forming a composite patterned layer of air and silicon nitride. The difference in refractive index between air and silicon nitride improves light extraction efficiency.

[0085] As in the above embodiment, the sponge protrusion microstructure 20 further includes a filling structure 22 , and the filling structure 22 is made of silicon dioxide material. Figure 8 This is a flow chart of another method for preparing a patterned composite substrate based on sponge protrusions provided by an embodiment of the present invention.Figure 8 The embodiment is optimized on the basis of the above-mentioned embodiment. Specifically, a plurality of sponge convex microstructures are prepared on one side in the thickness direction of the sapphire substrate. Specifically, the following can be refined:

[0086] On one side in the thickness direction of the sapphire substrate, silicon nitride material and silicon dioxide material are alternately grown in sequence to form a three-dimensional interpenetrating network structure layer.

[0087] The three-dimensional interpenetrating network structure layer is dry etched to form a plurality of sponge convex microstructures, and the sponge convex structure is formed with a sponge skeleton structure and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0088] As shown in the method can include the following steps: Figure 8

[0089] S210, providing a sapphire substrate.

[0090] S220, preparing a plurality of sponge convex microstructures on one side in the thickness direction of the sapphire substrate.

[0091] S230, on one side in the thickness direction of the sapphire substrate, silicon nitride material and silicon dioxide material are alternately grown in sequence to form a three-dimensional interpenetrating network structure layer.

[0092] Referring to (b) of the figure, Figure 7 On one side in the thickness direction of the sapphire substrate 10, silicon nitride material is generated by gas ratio reaction, and the silicon nitride material is deposited on the surface of the substrate. This process is not simply physical accumulation. The surface of the sapphire substrate 10 has a rough and uneven structure. Many crystal nuclei are generated during the reaction process. The crystal nuclei form an irregular silicon nitride network structure through continuous reaction, diffusion and fusion. After a period of time, the gas ratio is changed so that the deposited material is replaced by silicon dioxide. The silicon dioxide material is deposited in the gaps of the silicon nitride network structure. Through continuous alternation and repetition of the above process, a three-dimensional interpenetrating network structure layer 30 is finally formed, which has a silicon nitride skeleton structure and a silicon dioxide gap filler.

[0093] S240, dry etching the three-dimensional interpenetrating network structure layer to form a plurality of sponge convex microstructures, and the sponge convex structure is formed with a sponge skeleton structure and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0094] Referring to Figure 7 ​As shown in Fig. 4, a first photoresist layer 40 is coated on a part of the upper side of the three-dimensional interpenetrating network structure layer 30. The second photoresist layer 40 in this step can also be a positive or negative photoresist, and the coating process can also be spin coating or spraying, or can also be formed by a magnetron sputtering process or a plasma-enhanced chemical vapor deposition process. The present embodiment takes a negative photoresist as an example for specific description.

[0095] Referring to Figure 7 As shown in Fig. 5, after the negative photoresist is coated on the surface of the substrate, the exposed area is cured to form a solid structure insoluble in the developer, and the unexposed area is selectively dissolved and removed by the developer in the developing process, so as to realize the partial retention of the pattern. The cured structure forms a columnar mask layer 50, which can protect the internal cured structure and reduce the etching rate of the structure below during subsequent etching.

[0096] Referring to Figure 7 As shown in Fig. 6, the three-dimensional interpenetrating network structure layer 30 is dry etched. Due to the presence of the columnar mask layer 50, the gap part is etched first, and the protruding part is etched later, so as to finally form the sponge protruding microstructure 20.

[0097] Optionally, the three-dimensional interpenetrating network structure layer 30 is formed by alternately growing silicon nitride and silicon dioxide materials on one side of the sapphire substrate 10 in the thickness direction, including a first pulse phase and a second pulse phase alternately performed.

[0098] The first pulse phase includes:

[0099] NH3, SiH4 and N2 are used as three reaction gases, a first preset volume ratio is used, a first preset temperature range and a first preset reaction pressure range are used, a first pulse power is applied, a first preset reaction time is used, and a columnar β-Si3N4 crystal phase structure is grown.

[0100] The second pulse phase includes:

[0101] N2O, SiH4 and N2 are used as three reaction gases, a second preset volume ratio is used, a second preset temperature range and a second preset reaction pressure range are used, a second pulse power is applied, a second preset reaction time is used, and amorphous SiO2 is grown in the gap of the columnar β-Si3N4 crystal phase structure.

[0102] The first preset volume ratio of the three reaction gases NH3, SiH4 and N2 can be NH3:SiH4:N2=1:2:8, the first preset temperature range can be 380±20°C, the first preset reaction pressure range can be 1500±200 mTorr, the first pulse power can be 1200W, and the first preset time length can be 10-25s / cycle. The second preset volume ratio of the three reaction gases N2O, SiH4 and N2 can be N2O:SiH4:N2=5:1:3, the second preset reaction pressure range can be 800±100 mTorr, the second pulse power can be 800W, and the second preset time length can be 10-45s / cycle.

[0103] The gradient composite of the silicon nitride skeleton and the silica filling is realized by the pulsed gas switching, the columnar crystal preferred growth is induced by the high-frequency power modulation, and the mechanical support is improved. By adjusting the ratio of the first preset time length and the second preset time length, the refractive index can be changed, and then the light extraction efficiency is improved.

[0104] Optionally, the first pulse stage and the second pulse stage are repeatedly and alternately executed 12-30 times.

[0105] It can be understood that a single pulse stage can only form a single layer of columnar silicon nitride or silica interface, and multiple repeated and alternating executions can make the silicon nitride and silica closely arranged, improve the bending strength, and then improve the light extraction efficiency; more than 30 pulses will result in too long deposition time, too close arrangement of the silicon nitride and silica, reduced porosity, and then reduced stress buffering capacity and attenuated light extraction efficiency.

[0106] As in the above embodiment, the sponge protrusion microstructure 20 includes a core structure 23 and a shell structure 24, and the shell structure 24 covers the core structure 23. Figure 9 is another preparation method flow chart of a patterned composite substrate based on a sponge protrusion provided by the embodiment of the present application. Optionally, referring to Figure 9 , the embodiment is optimized on the basis of the above embodiment. Specifically, the three-dimensional interpenetrating network structure layer is dry etched to form a plurality of sponge protrusion microstructures, and the sponge protrusion structure has a sponge skeleton structure and a filling structure filled in at least part of the pores inside the sponge skeleton structure. Specifically, it can be refined as:

[0107] The three-dimensional interpenetrating network structure layer is dry etched to form a plurality of intermediate protrusion microstructures.

[0108] The sapphire substrate with the plurality of intermediate protruding microstructures is immersed in a hydrofluoric acid etching solution, and ultrasonic waves are sent to the surface of the sapphire substrate with the intermediate protruding microstructures according to a preset frequency band, so as to chemically etch the filling structure of the surface layer of the intermediate protruding microstructure for a third preset time length, so that the sponge skeleton structure forms a first part and a second part, the first part and the filling structure filled in the pores inside the first part form a core structure, and the second part forms a shell structure.

[0109] As shown in Figure 9 the method can include the following steps:

[0110] S310, providing a sapphire substrate.

[0111] S320, preparing a plurality of sponge protruding microstructures on one side in the thickness direction of the sapphire substrate.

[0112] S330, sequentially and alternately growing silicon nitride material and silicon dioxide material on one side in the thickness direction of the sapphire substrate to form a three-dimensional interpenetrating network structure layer.

[0113] S340, dry etching the three-dimensional interpenetrating network structure layer to form a plurality of sponge protruding microstructures, and sponge skeleton structures and filling structures filled in at least part of the pores inside the sponge skeleton structures are formed in the sponge protruding microstructures.

[0114] S350, dry etching the three-dimensional interpenetrating network structure layer to form a plurality of intermediate protruding microstructures.

[0115] In this step, the three-dimensional interpenetrating network structure layer 30 is processed into a plurality of intermediate protruding microstructures by dry etching, which can on the one hand control the geometric morphology of the intermediate protruding microstructures, and on the other hand, by utilizing the refractive index difference between silicon nitride and silicon dioxide, the light extraction efficiency is improved; and the other hand, by forming a porous skeleton structure, a support frame is provided for the subsequent filling process, so as to realize epitaxial stress buffering and structural stability enhancement.

[0116] S360, the sapphire substrate with the plurality of intermediate protruding microstructures is immersed in a hydrofluoric acid etching solution, and ultrasonic waves are sent to the surface of the sapphire substrate with the intermediate protruding microstructures according to a preset frequency band, so as to chemically etch the filling structure of the surface layer of the intermediate protruding microstructure for a third preset time length, so that the sponge skeleton structure forms a first part and a second part, the first part and the filling structure filled in the pores inside the first part form a core structure, and the second part forms a shell structure.

[0117] Reference Figure 7(f) Figure, the sapphire substrate 10 with multiple intermediate convex microstructure is immersed in hydrofluoric acid etching solution, hydrofluoric acid can react with silicon dioxide, and does not react with silicon nitride, so that the sponge skeleton structure 21 forms the first part 211 and the second part 212, the first part 211 and the filling structure 22 filled in the pores inside the first part 211 form the core structure 23, the composite pattern layer including silicon nitride and silicon dioxide; The second part 212 forms the shell structure 24, the silicon dioxide on the surface of the second part 212 reacts with hydrofluoric acid to form a silicon nitride sponge porous outer ring layer.

[0118] Wherein, the third preset time length can be 30-45 minutes, by adjusting the third preset time length, the height ratio and the bottom diameter ratio of the core structure 23 and the outer core structure 24 can be adjusted, and then the light extraction efficiency is adjusted.

[0119] Optionally, the preset frequency band f satisfies: 0.8MHZ≤f≤1.2MHZ.

[0120] It can be understood that the suitable frequency band ultrasonic wave is beneficial to the chemical reaction of the gap filler.

[0121] As in the above embodiment, the sponge convex microstructure 20 further includes a bonding layer 25, and the bonding layer 25 is located between the sponge skeleton structure 21 and the sapphire substrate 10. Figure 10 is another preparation method flow chart of the patterned composite substrate based on sponge convex provided by the embodiment of the present application, Figure 11 is Figure 10 The structure flow chart of the patterned composite substrate based on sponge convex is shown in the figure, and optionally, referring to Figure 10 and Figure 11 , this embodiment is optimized on the basis of the above-mentioned embodiment, specifically, on one side of the thickness direction of the sapphire substrate, the silicon nitride material and the silicon dioxide material are alternately grown in sequence before forming the three-dimensional interpenetrating network structure layer, and the following steps can be added:

[0122] The silicon nitride material is used to prepare an integral bonding layer on one side of the thickness direction of the sapphire substrate.

[0123] Specifically, the three-dimensional interpenetrating network structure layer is dry etched to form multiple sponge convex microstructures, and the sponge convex structure has a sponge skeleton structure and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0124] The three-dimensional interpenetrating network structure layer and the integral bonding layer are dry etched to form multiple sponge convex microstructures, and the sponge convex structure has a bonding layer, a sponge skeleton structure, and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0125] As shown in Figure 10 The method can include the following steps:

[0126] S410, providing a sapphire substrate.

[0127] S420, preparing a plurality of sponge convex microstructures on one side of the sapphire substrate in the thickness direction.

[0128] S430, using a silicon nitride material to prepare an integral bonding layer on one side of the sapphire substrate in the thickness direction.

[0129] Referring to Figure 11 (b) figure, the integral bonding layer 25 prepared in this step is located between the sponge skeleton structure 21 and the sapphire substrate 10, can create a refractive index difference between different materials, can improve the probability of photon escape, and at the same time, since the silicon nitride is not corroded by hydrofluoric acid, it can lay a solid foundation for the combination of the convex structure and the upper surface of the sapphire, so that the bonding force between the two is not destroyed by hydrofluoric acid, and the stability of the composite substrate is strengthened.

[0130] S440, alternately growing silicon nitride material and silicon dioxide material on one side of the sapphire substrate in the thickness direction to form a three-dimensional interpenetrating network structure layer.

[0131] S450, dry etching the three-dimensional interpenetrating network structure layer and the integral bonding layer to form a plurality of sponge convex microstructures, and the sponge convex structure is formed with a bonding layer, a sponge skeleton structure, and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0132] Referring to Figure 11 (f) figure, dry etching the three-dimensional interpenetrating network structure layer 30 and the integral bonding layer 25, the parts are more stable, and the connection reliability of the whole sponge convex microstructure 20 is strengthened.

[0133] S460, dry etching the three-dimensional interpenetrating network structure layer and the integral bonding layer to form a plurality of intermediate convex microstructures.

[0134] S470, immersing the sapphire substrate with a plurality of intermediate convex microstructures into a hydrofluoric acid etching solution, and sending ultrasonic waves according to a preset frequency band and front surface of the surface of the sapphire substrate with the intermediate convex microstructure to chemically etch the filling structure of the surface layer of the intermediate convex microstructure for a third preset time length, so that the sponge skeleton structure forms a first part and a second part, the first part and the filling structure filled in the pores inside the first part form a core structure, and the second part forms a shell structure.

[0135] As in the above embodiment, the sponge protrusion microstructure 20 further comprises a sapphire layer 26, which is integrally connected with the sapphire substrate 10, and the sponge skeleton structure 21 is located on the side of the sapphire layer 26 away from the sapphire substrate 10. Figure 12 is another flow chart of a preparation method of a sponge protrusion-based patterned composite substrate provided by an embodiment of the present application. Optionally, reference can be made to Figure 12 The present embodiment is an optimization based on the above-mentioned embodiments. Specifically, dry etching is performed on the three-dimensional interpenetrating network structure layer to form a plurality of sponge protrusion microstructures, and the sponge protrusion structure further comprises a sapphire layer, a sponge skeleton structure, and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0136] The three-dimensional interpenetrating network structure layer is over-etched to form a plurality of sponge protrusion microstructures, and the sponge protrusion structure further comprises a sapphire layer, a sponge skeleton structure, and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0137] As shown in Figure 12 , the method can comprise the following steps:

[0138] S510, providing a sapphire substrate.

[0139] S520, preparing a plurality of sponge protrusion microstructures on one side in the thickness direction of the sapphire substrate.

[0140] S530, alternately growing silicon nitride material and silicon dioxide material on one side in the thickness direction of the sapphire substrate to form a three-dimensional interpenetrating network structure layer.

[0141] S540, over-etching the three-dimensional interpenetrating network structure layer to form a plurality of sponge protrusion microstructures, and the sponge protrusion structure further comprises a sapphire layer, a sponge skeleton structure, and a filling structure filled in at least part of the pores inside the sponge skeleton structure.

[0142] When dry etching the three-dimensional interpenetrating network structure layer 30, part of the sapphire substrate 10 region will also be over-etched and damaged, causing the unetched part of the sapphire region to protrude, forming a sapphire layer 26. The sapphire layer 26 can act as a transition structure between the sapphire substrate 10 and the sponge protrusion microstructure 20, and can strengthen the combination of the sponge skeleton structure 21 and the sapphire substrate 10, buffer stress, and improve the stability of the structure by virtue of the chemical inertness and structural stability of sapphire.

[0143] S550, dry etching the three-dimensional interpenetrating network structure layer to form a plurality of intermediate protrusion microstructures.

[0144] S560, immerging the sapphire substrate with the plurality of intermediate protruding microstructures into a hydrofluoric acid etching solution, and sending ultrasonic waves to the surface of the sapphire substrate with the intermediate protruding microstructures according to a preset frequency band, so as to chemically etch the filling structure of the surface layer of the intermediate protruding microstructures for a third preset time length, so as to form a first part and a second part of the sponge skeleton structure, the first part and the filling structure filled in the pores inside the first part form a core structure, and the second part forms a shell structure.

[0145] It should be noted that the above only describes the preferred embodiments of the present application and the principles of the applied technology. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments, mutual combinations and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A patterned composite substrate based on sponge bumps, characterized in that, The application relates to a sapphire substrate and a method for manufacturing the same. The sapphire substrate comprises: a sapphire substrate; 2. The patterned composite substrate of claim 1, wherein, a plurality of sponge convex microstructures on one side of the sapphire substrate in the thickness direction; the sponge convex microstructure comprises a sponge skeleton structure prepared from a silicon nitride material, and the sponge skeleton structure has a three-dimensional interpenetrating network pore inside.

3. The patterned composite substrate of claim 2, wherein, The sponge convex microstructure further comprises a filling structure filled in at least part of the pores inside the sponge skeleton structure, and the filling structure is prepared from a silicon dioxide material. The sponge convex microstructure comprises a core structure and a shell structure, and the shell structure covers the core structure; 4. The patterned composite substrate of claim 3, wherein, The sponge skeleton structure comprises a first part and a second part, the core structure comprises the first part and the filling structure filled in the pores inside the first part, and the shell structure comprises the second part.

5. The patterned composite substrate of claim 3, wherein, The porosity of the sponge skeleton structure satisfies:

6. The patterned composite substrate of claim 3, wherein, The height H of the sponge convex microstructure satisfies 1.8 mu m <= H <= 3.5 mu m. The height of the core structure is H4, the bottom surface caliber of the core structure is W3, the height of the sponge convex microstructure is H3, and the bottom surface caliber of the sponge convex microstructure is W2.

7. The patterned composite substrate of claim 1, wherein, Wherein, 50% <= H4: H3 <= 80%; and / or, 50% <= W3: W2 <= 80%.

8. The patterned composite substrate of claim 7, wherein, The sponge convex microstructure further comprises a bonding layer between the sponge skeleton structure and the sapphire substrate, and the bonding layer is prepared from the silicon nitride material.

9. A method for fabricating a patterned composite substrate based on sponge bumps, characterized in that, The thickness H2 of the bonding layer satisfies 200 nm <= H2 <= 500 nm. The application relates to a sapphire substrate and a method for manufacturing the same. The sapphire substrate comprises:

10. The method of claim 9, wherein, providing a sapphire substrate; preparing a plurality of sponge convex microstructures on one side of the sapphire substrate in the thickness direction; wherein the sponge convex microstructure comprises a sponge skeleton structure prepared from a silicon nitride material, and the sponge skeleton structure has a three-dimensional interpenetrating network pore inside. The sponge convex microstructure further comprises a filling structure prepared from a silicon dioxide material; The method for manufacturing the sapphire substrate comprises:

11. The method of claim 10, wherein, growing the silicon nitride material and the silicon dioxide material alternately on one side of the sapphire substrate in the thickness direction to form a three-dimensional interpenetrating network structure layer; performing dry etching on the three-dimensional interpenetrating network structure layer to form a plurality of sponge convex microstructures, and the sponge convex structure is formed with the sponge skeleton structure and a filling structure filled in at least part of the pores inside the sponge skeleton structure. The method for manufacturing the sapphire substrate comprises: growing the silicon nitride material and the silicon dioxide material alternately on one side of the sapphire substrate in the thickness direction to form a three-dimensional interpenetrating network structure layer, which comprises a first pulse stage and a second pulse stage alternately executed; The first pulse stage comprises: using three reaction gases of NH3, SiH4 and N2, growing a columnar beta-Si3N4 crystal phase structure in a first preset temperature range and a first preset reaction pressure range by applying a first pulse power according to a first preset volume ratio and reacting for a first preset time length. The second pulse stage comprises: Growth of amorphous SiO2 in the gap of the columnar β-Si3N4 crystal phase structure by using N2O, SiH4 and N2 as reaction gases, according to a second preset volume ratio, in a second preset temperature range and a second preset reaction pressure range, applying a second pulse power for a second preset time length.

12. The method of claim 11, wherein, The first pulse phase and the second pulse phase are repeatedly performed alternately for 12-30 times.

13. The preparation method according to claim 10, characterized in that The sponge convex microstructure comprises a core structure and a shell structure, and the shell structure covers the core structure. The three-dimensional interpenetrating network structure layer is dry etched to form a plurality of sponge convex microstructures, and the sponge convex structure comprises the sponge skeleton structure and the filling structure filled in at least part of the pores inside the sponge skeleton structure. The three-dimensional interpenetrating network structure layer is dry etched to form a plurality of intermediate convex microstructures. The sapphire substrate with a plurality of intermediate convex microstructures is immersed in a hydrofluoric acid etching solution, and an ultrasonic wave is transmitted to the surface of the sapphire substrate with the intermediate convex microstructures according to a preset frequency band, so that the filling structure of the surface layer of the intermediate convex microstructure is chemically etched for a third preset time length, so that the sponge skeleton structure forms a first part and a second part, the first part and the filling structure filled in the pores inside the first part form the core structure, and the second part forms the shell structure.

14. The method of claim 10, wherein, The sponge convex microstructure further comprises a bonding layer between the sponge skeleton structure and the sapphire substrate. Before forming the three-dimensional interpenetrating network structure layer, the sapphire substrate is grown on one side in the thickness direction of the sapphire substrate, and the sapphire substrate is grown on one side in the thickness direction of the sapphire substrate. A bonding layer is prepared on one side in the thickness direction of the sapphire substrate by using a silicon nitride material. The three-dimensional interpenetrating network structure layer is dry etched to form a plurality of sponge convex microstructures, and the sponge convex structure comprises the sponge skeleton structure and the filling structure filled in at least part of the pores inside the sponge skeleton structure. The three-dimensional interpenetrating network structure layer and the bonding layer are dry etched to form a plurality of sponge convex microstructures, and the sponge convex structure comprises the bonding layer, the sponge skeleton structure, and the filling structure filled in at least part of the pores inside the sponge skeleton structure.

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