A patterned composite substrate and a preparation method thereof, and an LED chip

Abstract

The application relates to the technical field of semiconductors, in particular to a patterned composite substrate and a preparation method thereof and an LED chip. The preparation method comprises the following steps: providing a sapphire substrate; forming a plurality of spaced photoresist protrusions on the sapphire substrate; etching the sapphire substrate, so that the sapphire substrate forms grooves between adjacent photoresist protrusions; growing a silicon dioxide layer on the sapphire substrate; forming a plurality of spaced photoresist convex columns on the silicon dioxide layer, and the photoresist convex columns and the grooves are periodically staggered; etching the sapphire substrate, so that the grooves are exposed, and the silicon dioxide layer forms protruding structures on the surface of the sapphire substrate, to form a patterned composite substrate with the surface being periodically staggered with protruding structures and grooves, and a space is arranged between adjacent protruding structures and grooves; the prepared patterned composite substrate has higher definition and precision, and the surface is periodically staggered with protruding structures and grooves, which can more effectively reduce dislocations and defects of epitaxial materials, improve the quality of the epitaxial materials, and improve the light-emitting efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a patterned composite substrate and its preparation method, and an LED chip. Background Technology

[0002] Sapphire substrates are currently widely used as substrates for nitride epitaxial films in III-V LED devices. However, due to the significant lattice mismatch and difference in thermal expansion coefficients between nitrides and sapphire, the dislocation and defect density of the nitride material grown on the substrate is relatively high, affecting the luminous efficiency and lifetime of the device. Patterned Sapphire Substrate (PSS) technology is a substrate technology that fabricates periodic array patterns with fine structures on the surface of a sapphire substrate. This technology can effectively reduce the stress caused by lattice mismatch and alleviate dislocation generation, effectively reducing dislocations and defects in the epitaxial material, and has been widely used in nitride device fabrication. However, currently, conventional sapphire patterned substrates typically only form periodically arranged cones, domes, pyramids, and pillars on the substrate surface, with limited effect on reducing dislocations and defects in the epitaxial material. Summary of the Invention

[0003] The purpose of this invention is to provide a patterned composite substrate and its preparation method, as well as an LED chip, in light of the existing technological status quo.

[0004] The resulting patterned composite substrate has higher clarity and precision, and its surface features a periodic and staggered arrangement of raised structures and grooves, which can more effectively reduce dislocations and defects in the epitaxial material, improve the quality of the epitaxial material, and enhance luminous efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] First, the present invention provides a method for preparing a patterned composite substrate, comprising:

[0007] Provide sapphire substrates;

[0008] A first photoresist pattern is formed on the sapphire substrate, the first photoresist pattern comprising a plurality of spaced photoresist protrusions;

[0009] The sapphire substrate with the first photoresist pattern is etched to form an inwardly recessed groove between adjacent photoresist protrusions.

[0010] A silicon dioxide layer is grown on the sapphire substrate with the groove, the silicon dioxide layer filling the groove and spreading evenly on the surface of the sapphire substrate;

[0011] A second photoresist pattern is formed on the silicon dioxide layer. The second photoresist pattern includes a plurality of photoresist protrusions arranged at intervals, and the photoresist protrusions and the grooves are periodically staggered.

[0012] The sapphire substrate with the second photoresist pattern is etched to expose the grooves, and the silicon dioxide layer is formed into a protrusion structure on the surface of the sapphire substrate to form a patterned composite substrate with the protrusion structure and the grooves arranged in a periodic alternation on the surface, and a gap is provided between adjacent protrusion structures and grooves.

[0013] In some embodiments, the step of forming the first photoresist pattern on the sapphire substrate includes:

[0014] A negative photoresist is coated on the sapphire substrate, and the negative photoresist is exposed, developed or imprinted to form the first photoresist pattern. The viscosity of the negative photoresist is 36 cP to 56 cP.

[0015] In some embodiments, the step of forming a second photoresist pattern on the silicon dioxide layer includes:

[0016] A positive photoresist is coated on the silicon dioxide layer, and the positive photoresist is exposed, developed, or imprinted to form the second photoresist pattern.

[0017] The viscosity of the negative photoresist is greater than that of the positive photoresist, and the viscosity of the positive photoresist is 16 cP to 46 cP.

[0018] In some embodiments, the step of etching the sapphire substrate with the first photoresist pattern includes:

[0019] A CHF3 / O2 mixed gas is used as the etching gas to perform dry etching on the sapphire substrate with the first photoresist pattern until the first photoresist pattern is completely etched. The sapphire substrate forms an inwardly recessed groove between adjacent photoresist protrusions.

[0020] A BCl3 / Ar mixed gas is used as the etching gas to perform dry etching on the sapphire substrate with the groove preform formed, and the etching time is 5 min to 20 min to form the sapphire substrate with the groove.

[0021] In some embodiments, the step of etching the sapphire substrate with the second photoresist pattern includes:

[0022] A CHF3 / O2 mixed gas is used as the etching gas to perform dry etching on the sapphire substrate with the second photoresist pattern until the groove is exposed;

[0023] A BCl3 / Ar mixed gas was used as the etching gas to perform dry etching on the sapphire substrate exposed by the groove for 4 to 6 minutes, forming a patterned composite substrate with the raised structure and the groove arranged periodically on the surface.

[0024] In some embodiments, the number of photoresist protrusions and photoresist pillars are the same and they are arranged in a one-to-one correspondence. The centerlines of each corresponding photoresist protrusion and photoresist pillar coincide, and the relative distance between adjacent photoresist pillars is greater than the groove opening width between adjacent photoresist pillars.

[0025] In some embodiments, the depth of the groove is less than the height of the protrusion.

[0026] In some embodiments, in the step of growing a silicon dioxide layer on the sapphire substrate with the groove, wherein the silicon dioxide layer fills the groove and lies flat on the surface of the sapphire substrate, the depth of the groove is 1:1.8 to 3.0 of the growth thickness of the silicon dioxide layer.

[0027] Secondly, the present invention provides a patterned composite substrate, which is prepared according to the above-described method for preparing a patterned composite substrate;

[0028] The invention includes a sapphire substrate and a silicon dioxide layer disposed on the sapphire substrate. The sapphire substrate has a groove, and the silicon dioxide layer includes a protrusion structure. The protrusion structure and the groove are arranged in a periodic staggered manner, and there is a gap between adjacent protrusion structures and grooves.

[0029] Furthermore, the present invention provides an LED chip comprising the above-described patterned composite substrate.

[0030] The beneficial effects of this invention are as follows:

[0031] On the one hand, in this invention, the patterned composite substrate formed by the above-mentioned preparation method has a periodically staggered arrangement of surface protrusions and grooves, with gaps between adjacent protrusions and grooves. During the epitaxial material growth process, the grooves can cause dislocations to bend in direction, and under the action of adjacent protrusions, dislocation defects are annihilated and merged, blocking the upward extension of dislocations. The gaps between adjacent protrusions and grooves facilitate the merging of dislocations, thereby effectively reducing dislocation defects and more effectively reducing dislocations and defects in the epitaxial material, improving the quality of the epitaxial material, and enhancing luminous efficiency. On the other hand, when photoresist is coated on the surface of a substrate with uneven morphology, the high viscosity of the photoresist makes it difficult to spread it evenly in the surface depressions, resulting in blurred pattern edges. In this invention, grooves are first formed on the surface of a sapphire substrate through photolithography and etching, followed by the growth of a silicon dioxide layer. The silicon dioxide layer is then used to fill the grooves and form a flat surface. Photolithography and etching are then performed again to form a patterned composite substrate with a surface featuring a raised structure and grooves arranged periodically. Both photoresist patterns are formed on a flat surface without unevenness, ensuring uniform photoresist coating and resulting in clearer photoresist patterns. This leads to higher etching precision in the subsequent process, resulting in a patterned composite substrate with higher clarity and precision. The high-precision patterned substrate can effectively reduce the dislocation density of the epitaxial material, thereby further improving the crystal quality of the material and enhancing luminescence efficiency. Attached Figure Description

[0032] Figure 1 This is a flowchart illustrating a method for preparing a patterned composite substrate according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of a sapphire substrate coated with negative photoresist according to an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of the structure of a sapphire substrate with a first photoresist pattern according to an embodiment of the present invention.

[0035] Figure 4 This is a schematic diagram of the structure of a sapphire substrate with grooves according to an embodiment of the present invention.

[0036] Figure 5 This is a schematic diagram of the structure of a sapphire substrate with a silicon dioxide layer according to an embodiment of the present invention.

[0037] Figure 6 This is a schematic diagram of a sapphire substrate coated with positive photoresist according to an embodiment of the present invention.

[0038] Figure 7 This is a schematic diagram of the structure of a sapphire substrate with a second photoresist pattern according to an embodiment of the present invention.

[0039] Figure 8 This is a schematic diagram of the structure of the patterned composite substrate according to an embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.

[0041] First, see Figure 1 As shown, the present invention provides a method for preparing a patterned composite substrate, comprising:

[0042] S100. Provides a sapphire substrate 1;

[0043] S200. See also Figures 2 to 3 As shown, a first photoresist pattern is formed on the sapphire substrate 1, the first photoresist pattern including a plurality of photoresist protrusions 22 arranged at intervals of 5;

[0044] S300. See also Figure 4 As shown, the sapphire substrate 1 with the first photoresist pattern is etched to form an inwardly recessed groove 11 between adjacent photoresist protrusions 22 on the sapphire substrate 1.

[0045] S400. See also Figure 5 As shown, a silicon dioxide layer 3 is grown on the sapphire substrate 1 with the groove 11, and the silicon dioxide layer 3 fills the groove 11 and is laid flat on the surface of the sapphire substrate 1;

[0046] S500. See also Figures 6 to 7 As shown, a second photoresist pattern is formed on the silicon dioxide layer 3. The second photoresist pattern includes a plurality of photoresist protrusions 42 arranged at intervals of 5, and the photoresist protrusions 42 and the grooves 11 are periodically staggered.

[0047] S600. See also Figure 8 As shown, the sapphire substrate 1 with the second photoresist pattern is etched to expose the groove 11, and the silicon dioxide layer 3 forms a protrusion structure 31 on the surface of the sapphire substrate 1 to form a patterned composite substrate with the protrusion structure 31 and the groove 11 arranged periodically and alternately on the surface, and a gap 5 is provided between adjacent protrusion structures 31 and grooves 11.

[0048] In this invention, a clear first photoresist pattern is first formed on the flat surface of a sapphire substrate 1. Then, etching is performed to form clear grooves 11 on the sapphire surface. Subsequently, a silicon dioxide layer 3 is used to fill the grooves 11 and lay flat on the surface of the sapphire substrate 1. That is, the surface of the silicon dioxide layer 3 is flat, which facilitates the formation of a clear second photoresist pattern on the surface of the silicon dioxide layer 3. Then, etching is performed again to form a patterned composite substrate with a surface in which the raised structure 31 and the grooves 11 are periodically staggered.

[0049] On the one hand, in this invention, the surface protrusions 31 and grooves 11 of the patterned composite substrate formed by the above-described preparation method are periodically staggered, and a gap 5 is provided between adjacent protrusions 31 and grooves 11. During the epitaxial material growth process, the grooves 11 can cause the dislocation direction to bend, and under the action of the adjacent protrusions 31, dislocation defects are annihilated and merged, blocking the upward extension of dislocations. The gap 5 between adjacent protrusions 31 and grooves 11 facilitates the merging of dislocations, thereby effectively reducing dislocation defects, more effectively reducing dislocations and defects in the epitaxial material, improving the quality of the epitaxial material, and enhancing luminous efficiency. On the other hand, when photoresist is coated on the surface of a substrate with uneven morphology, due to the high viscosity of the photoresist, it is difficult to spread the photoresist evenly in the surface depressions, resulting in blurred pattern edges. In this invention, grooves 11 are first formed on the surface of a sapphire substrate 1 through photolithography and etching, followed by the growth of a silicon dioxide layer 3. The silicon dioxide layer 3 is then used to fill the grooves 11 and form a flat surface. Photolithography and etching are then performed again to form a patterned composite substrate with a surface featuring a periodic alternation of raised structures 31 and grooves 11. Both photoresist patterns are formed on a flat surface without unevenness, ensuring uniform coating and resulting in clearer photoresist patterns. This leads to higher etching precision in the subsequent process, resulting in a patterned composite substrate with higher clarity and precision. The high-precision patterned substrate can effectively reduce the dislocation density of the epitaxial material, thereby further improving the crystal quality of the material and enhancing luminescence efficiency.

[0050] In some embodiments, see Figures 1 to 3 As shown, in step S200, the step of forming the first photoresist pattern on the sapphire substrate 1 includes:

[0051] S210. A negative photoresist 21 is coated on the sapphire substrate 1. The negative photoresist 21 is exposed, developed, or imprinted to form the first photoresist pattern. The viscosity of the negative photoresist 21 is 36 cP to 56 cP.

[0052] For example, the viscosity of the negative photoresist 21 is 36 cP, 38 cP, 40 cP, 42 cP, 45 cP, 48 cP, 50 cP, 52 cP, 54 cP or 56 cP, but is not limited thereto.

[0053] In this embodiment, when forming the first photoresist pattern, a negative photoresist 21 with higher viscosity is used to provide higher adhesion. After exposure, the unexposed part will be retained, the pattern can be transferred more clearly, and a sharper sidewall profile can be provided to ensure that the shape and position of the groove 11 match the design pattern, and the accuracy and quality of forming the groove 11 are higher.

[0054] In some embodiments, see Figure 1 , Figure 6 and Figure 7 As shown, in step S500, the step of forming a second photoresist pattern on the silicon dioxide layer 3 includes:

[0055] S510. A positive photoresist 41 is coated on the silicon dioxide layer 3, and the positive photoresist 41 is exposed, developed or imprinted to form the second photoresist pattern.

[0056] The viscosity of the negative photoresist 21 is greater than that of the positive photoresist 41, and the viscosity of the positive photoresist 41 is 16 cP to 46 cP.

[0057] For example, the viscosity of the positive photoresist 41 is 16 cP, 18 cP, 20 cP, 22 cP, 25 cP, 28 cP, 30 cP, 32 cP, 35 cP, 38 cP, 40 cP, 42 cP, 44 cP or 46 cP, but is not limited thereto.

[0058] In this embodiment, when forming the second photoresist pattern, positive photoresist 41 is used. After exposure, the exposed part is retained to form the required convex pillar pattern. This method can directly form the required pattern through exposure without changing the polarity of the mask, simplifying the process and ensuring that the shape and position of the second photoresist pattern match the design drawing. The accuracy and quality of the formed convex structure 31 are higher.

[0059] In some embodiments, step S300, the step of etching the sapphire substrate 1 with the first photoresist pattern, includes:

[0060] S310. Using CHF3 / O2 mixed gas as etching gas, dry etching is performed on the sapphire substrate 1 with the first photoresist pattern until the first photoresist pattern is completely etched, and the sapphire substrate 1 forms an inwardly recessed groove prototype between adjacent photoresist protrusions 22.

[0061] S320. Using a BCl3 / Ar mixed gas as the etching gas, the sapphire substrate 1 with the groove 11 is dry etched for 5 min to 20 min to form the sapphire substrate 1 with the groove 11.

[0062] In this embodiment, segmented etching is performed in the first etching step. Specifically, CHF3 / O2 is first used as the etching gas. Compared with using CHF3 alone as the etching gas, using a CHF3 / O2 mixed gas is beneficial to improve etching selectivity, thereby enabling more precise etching of the groove prototype. Subsequently, BCl3 / Ar is used as the etching gas to perform dry etching on the sapphire substrate 1 with the groove prototype, and the entire surface of the sapphire substrate 1 with the groove prototype is treated. Compared with using BCl3 alone as the etching gas, the surface of the sapphire substrate 1 treated with BCl3 / Ar mixed gas is more uniform and smooth, which is beneficial to the subsequent formation of a high-quality silicon dioxide layer 3, reducing subsequent dislocation defects and improving luminous efficiency.

[0063] In some embodiments, step S600, the step of etching the sapphire substrate 1 with the second photoresist pattern, includes:

[0064] S610. Using CHF3 / O2 mixed gas as etching gas, the sapphire substrate 1 with the second photoresist pattern is dry etched until the groove 11 is exposed;

[0065] S620. Using a BCl3 / Ar mixed gas as the etching gas, the sapphire substrate 1 exposed by the groove 11 is dry etched for 4 min to 6 min to form a patterned composite substrate with the raised structure 31 and the groove 11 arranged periodically on the surface.

[0066] In this embodiment, segmented etching is performed in the second etching step. Specifically, CHF3 / O2 is first used as the etching gas to improve etching efficiency, and then BCl3 / Ar is used as the etching gas. BCl3 passes through the surface of the protruding structure 31 of the silicon dioxide material to form a thin film, which alleviates the etching efficiency of the protruding structure 31 in stage S620. On the other hand, the BCl3 / Ar mixed gas performs surface treatment on the exposed sapphire material, making the surface of the exposed sapphire material more uniform and smooth, which is conducive to the subsequent growth of epitaxial materials, reduces subsequent dislocation defects, and improves luminous efficiency.

[0067] In some embodiments, the flow rate of CHF3 in the CHF3 / O2 mixed gas is greater than 50% of the total flow rate of the mixed gas.

[0068] In some embodiments, the flow rate of BCl3 / Ar in the BCl3 / Ar mixed gas is greater than 50% of the total flow rate of the mixed gas.

[0069] In some embodiments, the number of photoresist protrusions 22 and photoresist protrusions 42 are the same and are arranged in a one-to-one correspondence. The center lines between the corresponding photoresist protrusions 22 and photoresist protrusions 42 coincide, and the relative distance between adjacent photoresist protrusions 42 is greater than the opening width of the groove 11 between adjacent photoresist protrusions 42.

[0070] In some embodiments, see Figure 8 As shown, the depth of the groove 11 is less than the height of the protrusion structure 31, which facilitates the bending and merging of dislocations and prevents the upward extension of dislocations.

[0071] In some embodiments, in the step of growing a silicon dioxide layer 3 on the sapphire substrate 1 with the groove 11, wherein the silicon dioxide layer 3 fills the groove 11 and is laid flat on the surface of the sapphire substrate 1, the depth of the groove 11 and the growth thickness of the silicon dioxide layer 3 are 1:1.8 to 3.0.

[0072] For example, the depth of the groove 11 is 1:1.8, 1:2.0, 1:2.2, 1:2.5, 1:2.8 or 1:3.0, but is not limited thereto.

[0073] It is understandable that the growth thickness of the silicon dioxide layer 3 refers to the thickness from the bottom of the groove 11 to the top surface. During the growth process, the lateral two-dimensional and three-dimensional growth of the silicon dioxide material can be controlled by controlling parameters such as growth pressure, growth temperature, and Mo source flow rate, so that the silicon dioxide layer 3 fills the groove 11 and is laid flat on the surface of the sapphire substrate 1. This can be achieved by existing technology, which will not be elaborated here.

[0074] Secondly, see Figure 1 and Figure 8 As shown, the present invention provides a patterned composite substrate, which is prepared according to the above-described method for preparing a patterned composite substrate;

[0075] The sapphire substrate 1 and the silicon dioxide layer 3 disposed on the sapphire substrate 1 are provided with grooves 11. The silicon dioxide layer 3 includes protrusions 31. The protrusions 31 and the grooves 11 are arranged in a periodic staggered manner, and there is a gap 5 between adjacent protrusions 31 and grooves 11.

[0076] On the one hand, in this invention, the surface protrusions 31 and grooves 11 of the patterned composite substrate formed by the above-described preparation method are periodically staggered, and a gap 5 is provided between adjacent protrusions 31 and grooves 11. During the epitaxial material growth process, the grooves 11 can cause the dislocation direction to bend, and under the action of the adjacent protrusions 31, dislocation defects are annihilated and merged, blocking the upward extension of dislocations. The gap 5 between adjacent protrusions 31 and grooves 11 facilitates the merging of dislocations, thereby effectively reducing dislocation defects, more effectively reducing dislocations and defects in the epitaxial material, improving the quality of the epitaxial material, and enhancing luminous efficiency. On the other hand, when photoresist is coated on the surface of a substrate with uneven morphology, due to the high viscosity of the photoresist, it is difficult to spread the photoresist evenly in the surface depressions, resulting in blurred pattern edges. In this invention, grooves 11 are first formed on the surface of a sapphire substrate 1 through photolithography and etching, followed by the growth of a silicon dioxide layer 3. The silicon dioxide layer 3 is then used to fill the grooves 11 and form a flat surface. Photolithography and etching are then performed again to form a patterned composite substrate with a surface featuring a periodic alternation of raised structures 31 and grooves 11. Both photoresist patterns are formed on a flat surface without unevenness, ensuring uniform coating and resulting in clearer photoresist patterns. This leads to higher etching precision in the subsequent process, resulting in a patterned composite substrate with higher clarity and precision. The high-precision patterned substrate can effectively reduce the dislocation density of the epitaxial material, thereby further improving the crystal quality of the material and enhancing luminescence efficiency.

[0077] Furthermore, the present invention provides an LED chip comprising the above-described patterned composite substrate.

[0078] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0079] Example 1

[0080] First, this embodiment discloses a method for preparing a patterned composite substrate, including:

[0081] S100 provides a sapphire substrate.

[0082] S200. A first photoresist pattern is formed on the sapphire substrate, the first photoresist pattern comprising a plurality of spaced photoresist protrusions:

[0083] S210. A negative photoresist is coated on the sapphire substrate, and the negative photoresist is exposed, developed or imprinted to form the first photoresist pattern, wherein the viscosity of the negative photoresist is 50 cP.

[0084] S300. Etching the sapphire substrate with the first photoresist pattern to form inwardly recessed grooves between adjacent photoresist protrusions on the sapphire substrate:

[0085] S310. Using CHF3 / O2 mixed gas as etching gas, dry etching is performed on the sapphire substrate with the first photoresist pattern until the first photoresist pattern is completely etched, and the sapphire substrate forms an inwardly recessed groove prototype between adjacent photoresist protrusions.

[0086] S320. Using a BCl3 / Ar mixed gas as the etching gas, the sapphire substrate with the groove preform is dry etched for 5 minutes to form the sapphire substrate with the groove.

[0087] S400. A silicon dioxide layer is grown on the sapphire substrate with the groove, the silicon dioxide layer filling the groove and spreading evenly on the surface of the sapphire substrate.

[0088] S500. A second photoresist pattern is formed on the silicon dioxide layer, the second photoresist pattern including a plurality of spaced photoresist protrusions, and the photoresist protrusions and the grooves are periodically staggered:

[0089] S510. A positive photoresist is coated on the silicon dioxide layer, and the positive photoresist is exposed, developed, or imprinted to form the second photoresist pattern;

[0090] The viscosity of the negative photoresist is greater than that of the positive photoresist, and the viscosity of the positive photoresist is 16 cP to 46 cP.

[0091] S600. The sapphire substrate with the second photoresist pattern is etched to expose the grooves, and the silicon dioxide layer is formed into a protrusion structure on the surface of the sapphire substrate to form a patterned composite substrate with the protrusion structure and the grooves arranged in a periodic alternating pattern on the surface, and a gap is provided between adjacent protrusion structures and grooves:

[0092] S610. Using a CHF3 / O2 mixed gas as the etching gas, the sapphire substrate with the second photoresist pattern is dry etched until the groove is exposed;

[0093] S620. Using a BCl3 / Ar mixed gas as the etching gas, the sapphire substrate exposed by the groove is dry etched for 4 minutes to form a patterned composite substrate with the raised structure and the groove arranged periodically on the surface.

[0094] In this embodiment, the number of photoresist protrusions and photoresist pillars are the same and they are arranged in a one-to-one correspondence. The center lines between each corresponding photoresist protrusion and photoresist pillar coincide, and the relative distance between adjacent photoresist pillars is greater than the groove opening width between adjacent photoresist pillars.

[0095] In this embodiment, the depth of the groove is less than the height of the protrusion.

[0096] In this embodiment, in the step of growing a silicon dioxide layer on the sapphire substrate with the groove, and the silicon dioxide layer filling the groove and spreading evenly on the surface of the sapphire substrate, the depth of the groove and the growth thickness of the silicon dioxide layer are 1:2.0.

[0097] Secondly, this embodiment discloses a patterned composite substrate, which is prepared according to the above-described method for preparing a patterned composite substrate;

[0098] The invention includes a sapphire substrate and a silicon dioxide layer disposed on the sapphire substrate. The sapphire substrate has a groove, and the silicon dioxide layer includes a protrusion structure. The protrusion structure and the groove are arranged in a periodic staggered manner, and there is a gap between adjacent protrusion structures and grooves.

[0099] Furthermore, this embodiment discloses an LED chip, including the patterned composite substrate described above.

[0100] Example 2

[0101] First, this embodiment discloses a method for preparing a patterned composite substrate, including:

[0102] S100 provides a sapphire substrate.

[0103] S200. A first photoresist pattern is formed on the sapphire substrate, the first photoresist pattern comprising a plurality of spaced photoresist protrusions:

[0104] S210. A negative photoresist is coated on the sapphire substrate, and the negative photoresist is exposed, developed or imprinted to form the first photoresist pattern, wherein the viscosity of the negative photoresist is 50 cP.

[0105] S300. Etching the sapphire substrate with the first photoresist pattern to form inwardly recessed grooves between adjacent photoresist protrusions on the sapphire substrate:

[0106] S310'. Using a CHF3 / O2 mixed gas as the etching gas, the sapphire substrate with the first photoresist pattern is dry etched until the first photoresist pattern is completely etched, and the sapphire substrate forms an inwardly recessed groove between adjacent photoresist protrusions.

[0107] S400. A silicon dioxide layer is grown on the sapphire substrate with the groove, the silicon dioxide layer filling the groove and spreading evenly on the surface of the sapphire substrate.

[0108] S500. A second photoresist pattern is formed on the silicon dioxide layer, the second photoresist pattern including a plurality of spaced photoresist protrusions, and the photoresist protrusions and the grooves are periodically staggered:

[0109] S510. A positive photoresist is coated on the silicon dioxide layer, and the positive photoresist is exposed, developed, or imprinted to form the second photoresist pattern;

[0110] The viscosity of the negative photoresist is greater than that of the positive photoresist, and the viscosity of the positive photoresist is 16 cP to 46 cP.

[0111] S600. The sapphire substrate with the second photoresist pattern is etched to expose the grooves, and the silicon dioxide layer is formed into a protrusion structure on the surface of the sapphire substrate to form a patterned composite substrate with the protrusion structure and the grooves arranged in a periodic alternating pattern on the surface, and a gap is provided between adjacent protrusion structures and grooves:

[0112] S610'. Using a CHF3 / O2 mixed gas as the etching gas, the sapphire substrate with the second photoresist pattern is dry etched until the grooves are exposed, forming a patterned composite substrate with the raised structure and the grooves arranged periodically on the surface.

[0113] In this embodiment, the number of photoresist protrusions and photoresist pillars are the same and they are arranged in a one-to-one correspondence. The center lines between each corresponding photoresist protrusion and photoresist pillar coincide, and the relative distance between adjacent photoresist pillars is greater than the groove opening width between adjacent photoresist pillars.

[0114] In this embodiment, the depth of the groove is less than the height of the protrusion.

[0115] In this embodiment, in the step of growing a silicon dioxide layer on the sapphire substrate with the groove, and the silicon dioxide layer filling the groove and spreading evenly on the surface of the sapphire substrate, the depth of the groove and the growth thickness of the silicon dioxide layer are 1:2.0.

[0116] Secondly, this embodiment discloses a patterned composite substrate, which is prepared according to the above-described method for preparing a patterned composite substrate;

[0117] The invention includes a sapphire substrate and a silicon dioxide layer disposed on the sapphire substrate. The sapphire substrate has a groove, and the silicon dioxide layer includes a protrusion structure. The protrusion structure and the groove are arranged in a periodic staggered manner, and there is a gap between adjacent protrusion structures and grooves.

[0118] Furthermore, this embodiment discloses an LED chip, including the patterned composite substrate described above.

[0119] Comparative Example 1

[0120] This comparative example discloses a patterned substrate, comprising:

[0121] S11. Provides a sapphire substrate;

[0122] S12. A SiO2 layer is grown on the sapphire substrate;

[0123] S13. A first layer of photoresist is applied to the SiO2 layer, and several first photoresist pillars are formed by development and exposure.

[0124] S14. Dry etching of the sapphire substrate with the first photoresist pillars to form several protrusion structures in the SiO2 layer;

[0125] S15. A second layer of photoresist is applied to a sapphire substrate with several protrusions, and several second photoresist pillars are formed by development and exposure, and the bottom width of the second photoresist pillars is greater than the corresponding protrusion structure.

[0126] S16. Dry etching of the sapphire substrate with the second photoresist pillars, forming grooves between adjacent protrusions to form a patterned composite substrate with a surface in which protrusions and grooves are periodically alternating, and a gap is provided between adjacent protrusions and grooves.

[0127] Comparative Example 2

[0128] This comparative example discloses a patterned substrate, comprising:

[0129] S21. Provides a sapphire substrate;

[0130] S22. A SiO2 layer is grown on the sapphire substrate;

[0131] S23. A first layer of photoresist is applied to the SiO2 layer, and several first photoresist pillars are formed by development and exposure.

[0132] S24. Dry etching of the sapphire substrate with the first photoresist pillars to form several protrusion structures in the SiO2 layer;

[0133] S25. Dry etching with BCl3 is performed on a sapphire substrate with several protrusions to form grooves between adjacent protrusion structures;

[0134] S26. Etching in a buffered oxidizing etchant to create a gap between adjacent protrusions and grooves;

[0135] S27. The substrate is dry-etched using a mixture of boron trichloride and tetrafluoromethane in the previous step to form a patterned composite substrate with a periodically alternating pattern of raised structures and grooves on the surface, and there is a gap between adjacent raised structures and grooves.

[0136] Experimental test:

[0137] 1. Test subjects: Examples 1 to 2 and Comparative Examples 1 to 2;

[0138] 2. Testing Method:

[0139] 1) Observe and compare the pattern clarity of the patterned composite substrates prepared in each experimental group under a microscope;

[0140] 2) Take 50 chips from each experimental group and test their photoelectric performance, brightness and antistatic ability, and take the average value.

[0141] 3) The test results are shown in Table 1 below:

[0142] Table 1 Test Results

[0143]

[0144] Experimental results show that the patterned composite substrates prepared by the method of the present invention in Examples 1 and 2 are clearer, and their brightness and antistatic ability are better than those in Comparative Examples 1 and 2. Among them, Example 1 has better performance, while the patterns in Comparative Examples 1 and 2 have local deformation and poor brightness and antistatic ability. The reason may be that in Comparative Example 1, photoresist is filled in the groove, which makes it difficult to ensure uniform coating of photoresist, affecting the clarity of subsequent patterns, and the photoresist is difficult to remove completely. Comparative Example 2 uses a wet process, which makes it difficult to control the shape trend of the surface morphology.

[0145] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method of fabricating a patterned composite substrate, characterized by, The application relates to a method for preparing a patterned composite substrate. The method comprises the following steps: providing a sapphire substrate; forming a first photoresist pattern on the sapphire substrate, wherein the first photoresist pattern comprises a plurality of photoresist protrusions arranged at intervals; etching the sapphire substrate with the first photoresist pattern, so that the sapphire substrate forms inwardly-recessed grooves between adjacent photoresist protrusions; growing a silicon dioxide layer on the sapphire substrate with the grooves, wherein the silicon dioxide layer fills the grooves and covers the surface of the sapphire substrate; forming a second photoresist pattern on the silicon dioxide layer, wherein the second photoresist pattern comprises a plurality of photoresist protrusions arranged at intervals, and the photoresist protrusions and the grooves are arranged in a periodic staggered manner; 2. The method of claim 1, wherein the patterned composite substrate is prepared by a method comprising: etching the sapphire substrate with the second photoresist pattern, so that the grooves are exposed, and the silicon dioxide layer forms protruding structures on the surface of the sapphire substrate, thereby forming a patterned composite substrate with the protruding structures and the grooves arranged in a periodic staggered manner on the surface, and a space is arranged between adjacent protruding structures and grooves. The step of forming the first photoresist pattern on the sapphire substrate comprises the following steps:

3. The method of claim 2, wherein the patterned composite substrate is prepared by a method comprising: coating a negative photoresist on the sapphire substrate, wherein the negative photoresist is exposed and developed or imprinted to form the first photoresist pattern, and the viscosity of the negative photoresist is 36 cP to 56 cP. The step of forming the second photoresist pattern on the silicon dioxide layer comprises the following steps: coating a positive photoresist on the silicon dioxide layer, wherein the positive photoresist is exposed and developed or imprinted to form the second photoresist pattern; 4. The method of claim 1, wherein the patterned composite substrate is prepared by a method comprising: wherein the viscosity of the negative photoresist is greater than the viscosity of the positive photoresist, and the viscosity of the positive photoresist is 16 cP to 46 cP. The step of etching the sapphire substrate with the first photoresist pattern comprises the following steps: using CHF3 / O2 mixed gas as etching gas to dry-etch the sapphire substrate with the first photoresist pattern, until the first photoresist pattern is completely etched, and the sapphire substrate forms a preliminary groove recessed inwardly between adjacent photoresist protrusions; 5. The method for preparing a patterned composite substrate according to claim 1, characterized in that, using BCl3 / Ar mixed gas as etching gas to dry-etch the sapphire substrate with the preliminary groove, and the etching time is 5 min to 20 min, thereby forming the sapphire substrate with the grooves. The step of etching the sapphire substrate with the second photoresist pattern comprises the following steps: using CHF3 / O2 mixed gas as etching gas to dry-etch the sapphire substrate with the second photoresist pattern, until the grooves are exposed; using BCl3 / Ar mixed gas as etching gas to dry-etch the sapphire substrate with the exposed grooves, and the etching time is 4 min to 6 min, thereby forming a patterned composite substrate with the protruding structures and the grooves arranged in a periodic staggered manner on the surface.

6. The method of claim 1, wherein the patterned composite substrate is prepared by a method comprising: The photoresist protrusions are arranged in the same number and one-to-one correspondence with the photoresist columns, the midlines between each corresponding photoresist protrusion and photoresist column coincide, and the relative distance between adjacent photoresist columns is greater than the groove opening width between adjacent photoresist columns.

7. The method for preparing a patterned composite substrate according to claim 1, characterized in that, The depth of the groove is less than the height of the protrusion structure.

8. The method for preparing a patterned composite substrate according to claim 1, characterized in that, In the step of growing a silicon dioxide layer on the sapphire substrate with the groove, the depth of the groove to the growth thickness of the silicon dioxide layer is 1:1.8-3.

0.

9. A patterned composite substrate, characterized in that, A method for preparing a patterned composite substrate according to any one of claims 1-8; The patterned composite substrate comprises a sapphire substrate and a silicon dioxide layer disposed on the sapphire substrate, the sapphire substrate is provided with a groove, and the silicon dioxide layer comprises a protrusion structure, the protrusion structure and the groove are periodically staggered, and a spacing is provided between adjacent protrusion structures and grooves.

10. An LED chip, characterized by The patterned composite substrate according to claim 9.

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