Patterned composite substrate, preparation method thereof and LED chip

Abstract

The invention relates to the technical field of semiconductors, in particular to a patterned composite substrate, a preparation method thereof and an LED chip. The preparation method comprises the following steps: providing a sapphire substrate; forming a plurality of photoresist bulges which are arranged at intervals on the sapphire substrate; etching the sapphire substrate to enable the sapphire substrate to form a groove between the adjacent photoresist bulges; growing a silicon dioxide layer on the sapphire substrate; forming a plurality of photoresist convex columns which are arranged at intervals on the silicon dioxide layer, wherein the photoresist convex columns and the grooves are periodically arranged in a staggered manner; and etching the sapphire substrate to expose the grooves, and enabling the silicon dioxide layer to form bulge structures on the surface of the sapphire substrate, so as to form the patterned composite substrate with the surface in which the bulge structures and the grooves are periodically staggered, and a gap is formed between the adjacent bulge structures and the grooves, so that the prepared patterned composite substrate is higher in definition and precision, and the prepared patterned composite substrate is more uniform in thickness. And the surface is of a convex structure and is periodically spaced and staggered with the grooves, so that dislocation and defects of the epitaxial material can be more effectively reduced, the quality of the epitaxial material is improved, and the luminous efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a patterned composite substrate and a preparation method thereof, and an LED chip. Background Art

[0002] Sapphire substrates are currently widely used as substrates for nitride epitaxial thin films of III-V LED devices. However, due to the large lattice mismatch and thermal expansion coefficient difference between nitride and sapphire, the dislocation and defect density of the amide material grown on the substrate is large, which affects the luminous efficiency and life of the device. Sapphire patterned substrate (Patterned Sapphire Substrate, PSS for short) technology is a substrate technology for making periodic array patterns with fine structures on the surface of sapphire substrates. This technology can effectively reduce the stress caused by lattice mismatch, while alleviating the generation of dislocations, effectively reducing the dislocations and defects of epitaxial materials, and has been widely used in the preparation of nitride devices. However, at present, conventional sapphire patterned substrates usually only form periodically arranged cones, domes, pyramids and columns on the substrate surface, and the effect of reducing dislocations and defects of epitaxial materials is limited. Summary of the invention

[0003] The purpose of the present invention is to provide a patterned composite substrate and a preparation method thereof, and an LED chip in view of the existing technical status.

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

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

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

[0007] Providing a sapphire substrate;

[0008] forming a first photoresist pattern on the sapphire substrate, wherein the first photoresist pattern comprises a plurality of photoresist protrusions arranged at intervals;

[0009] Etching the sapphire substrate with the first photoresist pattern so that the sapphire substrate forms inwardly recessed grooves between adjacent photoresist protrusions;

[0010] Growing a silicon dioxide layer on the sapphire substrate with the groove, wherein the silicon dioxide layer fills the groove and is spread on the surface of the sapphire substrate;

[0011] Forming a second photoresist pattern on the silicon dioxide layer, wherein the second photoresist pattern comprises a plurality of spaced photoresist convex columns, and the photoresist convex columns and the grooves are periodically staggered;

[0012] The sapphire substrate with the second photoresist pattern is etched to expose the grooves and to form a protruding structure on the surface of the sapphire substrate with the silicon dioxide layer, so as to form a patterned composite substrate with the protruding structures and the grooves periodically and alternately arranged on the surface, and with gaps between adjacent protruding structures and the grooves.

[0013] In some embodiments, the step of forming a 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 embossed to form the first photoresist pattern, and 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 comprises:

[0016] Coating a positive photoresist on the silicon dioxide layer, and forming the second photoresist pattern by exposing, developing or embossing the positive photoresist;

[0017] 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.

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

[0019] Using CHF3 / O2 mixed gas as etching gas, dry etching the sapphire substrate with the first photoresist pattern until the first photoresist pattern is completely etched and a groove prototype that is inwardly concave is formed between adjacent photoresist protrusions on the sapphire substrate;

[0020] The sapphire substrate with the groove prototype is dry-etched using a BCl3 / Ar mixed gas as an etching gas for 5 minutes to 20 minutes to form the sapphire substrate with the groove.

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

[0022] Using a CHF3 / O2 mixed gas as an etching gas, dry etching the sapphire substrate with the second photoresist pattern until the groove is exposed;

[0023] BCl3 / Ar mixed gas is used as etching gas to perform dry etching on the sapphire substrate with the groove exposed, and the etching process lasts for 4 to 6 minutes to form a patterned composite substrate with the protrusion structure and the grooves periodically and alternately arranged on the surface.

[0024] In some embodiments, the number of the photoresist protrusions and the photoresist columns are the same and are arranged in one-to-one correspondence, the midlines between the corresponding photoresist protrusions and the photoresist columns coincide, and the relative distance between adjacent photoresist columns is greater than the groove opening width between adjacent photoresist columns.

[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, and filling the groove with the silicon dioxide layer and spreading it on the surface of the sapphire substrate, the depth of the groove: the growth thickness of the silicon dioxide layer is 1:1.8-3.0.

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

[0028] It comprises a sapphire substrate and a silicon dioxide layer arranged on the sapphire substrate, wherein the sapphire substrate is provided with grooves, and the silicon dioxide layer comprises protruding structures, wherein the protruding structures and the grooves are periodically staggered and arranged, and intervals are arranged between adjacent protruding structures and the grooves.

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

[0030] The beneficial effects of the present invention are:

[0031] On the one hand, in the present invention, the surface protrusions and grooves of the patterned composite substrate formed by the above-mentioned preparation method are periodically staggered, and there is a gap between adjacent protrusions and grooves. During the growth of the epitaxial material, the setting of the grooves can cause the dislocation direction to bend, and under the action of the adjacent protrusions, the dislocation defects are annihilated and merged, and the upward extension of the dislocation is blocked. The intervals between the adjacent protrusions and grooves are conducive to the merging of dislocations, thereby effectively reducing dislocation defects, more effectively reducing dislocations and defects of epitaxial materials, improving the quality of epitaxial materials, and improving luminous efficiency. On the other hand, when applying photoresist on the surface of a substrate with a concave-convex morphology, due to the high viscosity of the photoresist, the photoresist is difficult to apply evenly in the surface depressions, which leads to blurred pattern edges. In the present invention, since grooves are first formed on the surface of the sapphire substrate by photolithography and etching, and then a silicon dioxide layer is grown, the grooves are filled with the silicon dioxide layer to form a flat surface, and then photolithography and etching are performed to form a graphic composite substrate with a surface having protruding structures and grooves arranged periodically and staggered. The two photoresist patterns are formed on a flat surface without concave-convex morphology, which can ensure uniform coating, and the formed photoresist pattern is clearer, thereby making the subsequent etching accuracy higher. The final graphic composite substrate has higher clarity and accuracy. The high-precision graphic substrate can effectively reduce the dislocation density of the epitaxial material, thereby further improving the crystal quality of the material and enhancing the luminous efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

[0036] Figure 5 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 It is a schematic structural diagram of a sapphire substrate coated with a positive photoresist according to an embodiment of the present invention.

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

[0039] Figure 8 Schematic diagram of the structure of a patterned composite substrate according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is 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. Providing a sapphire substrate 1;

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

[0044] S300.See Figure 4 As shown, the sapphire substrate 1 with the first photoresist pattern is etched so that the sapphire substrate 1 forms an inwardly recessed groove 11 between adjacent photoresist protrusions 22;

[0045] S400.See 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 spread flat on the surface of the sapphire substrate 1;

[0046] S500. Figure 6 to Figure 7 As shown, a second photoresist pattern is formed on the silicon dioxide layer 3, wherein the second photoresist pattern includes a plurality of photoresist convex columns 42 arranged at intervals 5, and the photoresist convex columns 42 and the grooves 11 are periodically staggered;

[0047] S600.See 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 protruding structure 31 on the surface of the sapphire substrate 1, so as to form a patterned composite substrate with the protruding structures 31 and the grooves 11 periodically and alternately arranged on the surface, and a gap 5 is provided between adjacent protruding structures 31 and the grooves 11.

[0048] In the present invention, a clear first photoresist pattern is first formed on the flat surface of the sapphire substrate 1, and then etching is performed to form clear grooves 11 on the sapphire surface. Subsequently, the grooves 11 are filled with the silicon dioxide layer 3 and spread 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. Subsequently, etching is performed again to form a patterned composite substrate with a surface having protruding structures 31 and grooves 11 periodically arranged in an alternating manner.

[0049] On the one hand, in the present invention, the surface protrusion structures 31 and the grooves 11 of the patterned composite substrate formed by the above-mentioned preparation method are periodically staggered, and a gap 5 is provided between adjacent protrusion structures 31 and grooves 11. During the growth of the epitaxial material, the setting of the groove 11 can cause the dislocation direction to bend, and under the action of the adjacent protrusion structures 31, the dislocation defects are annihilated and merged, and the upward extension of the dislocation is blocked. The gap 5 is provided between the adjacent protrusion structures 31 and the grooves 11, which is conducive to the merging of dislocations, thereby effectively reducing dislocation defects, more effectively reducing dislocations and defects of epitaxial materials, improving the quality of epitaxial materials, and improving luminous efficiency. On the other hand, when applying photoresist on the surface of a substrate with a concave-convex morphology, due to the high viscosity of the photoresist, the photoresist is difficult to be evenly applied in the surface depressions, which leads to blurred pattern edges. In the present invention, the grooves 11 are first formed on the surface of the sapphire substrate 1 by means of photolithography and etching, and then the silicon dioxide layer 3 is grown, and the grooves 11 are filled with the silicon dioxide layer 3 to form a flat surface, and then photolithography and etching are performed to form a graphic composite substrate with a surface having protruding structures 31 and grooves 11 arranged periodically and staggered. The two photoresist patterns are formed on a flat surface without concave-convex morphology, which can ensure uniform coating, and the formed photoresist pattern is clearer, thereby making the subsequent etching accuracy higher. The final graphic composite substrate has higher clarity and accuracy, and the high-precision graphic substrate can effectively reduce the dislocation density of the epitaxial material, thereby further improving the crystal quality of the material and enhancing the luminous efficiency.

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

[0051] S210. Coating a negative photoresist 21 on the sapphire substrate 1, the negative photoresist 21 is exposed, developed or embossed to form the first photoresist pattern, and the viscosity of the negative photoresist 21 is 36 cP to 56 cP.

[0052] Illustratively, 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, ensuring that the shape and position of the groove 11 match the design pattern, thereby forming the groove 11 with higher accuracy and quality.

[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 embossed to form the second photoresist pattern;

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

[0057] Illustratively, 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, a positive photoresist 41 is used. After exposure, the exposed portion will be retained to form the desired convex column pattern. This method can directly form the desired pattern by 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 pattern, so that the formed convex structure 31 has higher accuracy and quality.

[0059] In some embodiments, in 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 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 concave groove prototype between adjacent photoresist protrusions 22;

[0061] S320. Using BCl3 / Ar mixed gas as etching gas, dry-etching the sapphire substrate 1 formed with the groove prototype for 5 minutes to 20 minutes to form the sapphire substrate 1 with the groove 11.

[0062] In this embodiment, in the first etching step, segmented etching is performed. Specifically, CHF3 / O2 is first used as an etching gas. Compared with using CHF3 alone as an etching gas, using a CHF3 / O2 mixed gas is beneficial to improving the etching selectivity, so that the groove prototype can be etched more accurately. Subsequently, BCl3 / Ar is used as an etching gas to dry-etch the sapphire substrate 1 with the groove prototype, and the surface of the sapphire substrate 1 with the groove prototype is processed as a whole. Compared with using BCl3 alone as an etching gas, the surface of the sapphire substrate 1 treated with the BCl3 / Ar mixed gas is more uniform and smooth, which is beneficial to the subsequent formation of a high-quality silicon dioxide layer 3, reduces subsequent dislocation defects, and improves luminescence efficiency.

[0063] In some embodiments, in 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, dry-etching the sapphire substrate 1 with the second photoresist pattern until the groove 11 is exposed;

[0065] S620. Use BCl3 / Ar mixed gas as etching gas to dry-etch the sapphire substrate 1 exposed outside the groove 11 for 4 to 6 minutes to form a patterned composite substrate with the protruding structures 31 and the grooves 11 periodically and alternately arranged on the surface.

[0066] In this embodiment, in the second etching step, segmented etching is performed. Specifically, CHF3 / O2 is first used as an etching gas to improve the etching efficiency, and then BCl3 / Ar is used as an etching gas. BCl3 forms a thin film on the surface of the protruding structure 31 of the silicon dioxide material, thereby alleviating the etching efficiency of the protruding structure 31 in the S620 stage. In contrast, 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 beneficial to the subsequent growth of epitaxial materials, reduces subsequent dislocation defects, and improves the luminous efficiency.

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

[0068] In some embodiments, in the BCl 3 / Ar mixed gas, the flow rate of BCl 3 / is greater than 50% of the total flow rate of the mixed gas.

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

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

[0071] In some embodiments, in the step of growing the silicon dioxide layer 3 on the sapphire substrate 1 with the groove 11, and the silicon dioxide layer 3 filling the groove 11 and spreading it on the surface of the sapphire substrate 1, the depth of the groove 11: the growth thickness of the silicon dioxide layer 3 is 1:1.8~3.0.

[0072] Exemplarily, the depth of the groove 11 : the growth thickness of the silicon dioxide layer 3 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 can be understood that the growth thickness of the silicon dioxide layer 3 refers to the thickness from the bottom of the groove 11 to the uppermost surface. During the growth process, the lateral two-dimensional growth 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 flattened on the surface of the sapphire substrate 1. This can be achieved through existing technologies and will not be repeated 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-mentioned method for preparing a patterned composite substrate;

[0075] The invention comprises a sapphire substrate 1 and a silicon dioxide layer 3 arranged on the sapphire substrate 1, wherein the sapphire substrate 1 is provided with a groove 11, and the silicon dioxide layer 3 comprises a protruding structure 31, wherein the protruding structure 31 and the groove 11 are periodically staggered and arranged, and a gap 5 is arranged between adjacent protruding structures 31 and the groove 11.

[0076] On the one hand, in the present invention, the surface protrusion structures 31 and the grooves 11 of the patterned composite substrate formed by the above-mentioned preparation method are periodically staggered, and a gap 5 is provided between adjacent protrusion structures 31 and grooves 11. During the growth of the epitaxial material, the setting of the groove 11 can cause the dislocation direction to bend, and under the action of the adjacent protrusion structures 31, the dislocation defects are annihilated and merged, and the upward extension of the dislocation is blocked. The gap 5 is provided between the adjacent protrusion structures 31 and the grooves 11, which is conducive to the merging of dislocations, thereby effectively reducing dislocation defects, more effectively reducing dislocations and defects of epitaxial materials, improving the quality of epitaxial materials, and improving luminous efficiency. On the other hand, when applying photoresist on the surface of a substrate with a concave-convex morphology, due to the high viscosity of the photoresist, the photoresist is difficult to be evenly applied in the surface depressions, which leads to blurred pattern edges. In the present invention, the grooves 11 are first formed on the surface of the sapphire substrate 1 by means of photolithography and etching, and then the silicon dioxide layer 3 is grown, and the grooves 11 are filled with the silicon dioxide layer 3 to form a flat surface, and then photolithography and etching are performed to form a graphic composite substrate with a surface having protruding structures 31 and grooves 11 arranged periodically and staggered. The two photoresist patterns are formed on a flat surface without concave-convex morphology, which can ensure uniform coating, and the formed photoresist pattern is clearer, thereby making the subsequent etching accuracy higher. The final graphic composite substrate has higher clarity and accuracy, and the high-precision graphic substrate can effectively reduce the dislocation density of the epitaxial material, thereby further improving the crystal quality of the material and enhancing the luminous efficiency.

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

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

[0079] Example 1

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

[0081] S100. Provide a sapphire substrate.

[0082] S200. Forming a first photoresist pattern on the sapphire substrate, wherein the first photoresist pattern includes a plurality of photoresist protrusions arranged at intervals:

[0083] S210. Coating a negative photoresist on the sapphire substrate, the negative photoresist is exposed, developed or embossed to form the first photoresist pattern, and 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 the sapphire substrate with the first photoresist pattern until the first photoresist pattern is completely etched, and the sapphire substrate forms an inwardly concave groove prototype between adjacent photoresist protrusions;

[0086] S320. Use BCl3 / Ar mixed gas as etching gas to perform dry etching on the sapphire substrate with the groove prototype formed thereon for 5 minutes to form the sapphire substrate with the groove.

[0087] S400. Growing a silicon dioxide layer on the sapphire substrate with the groove, wherein the silicon dioxide layer fills the groove and is spread flat on the surface of the sapphire substrate.

[0088] S500. Forming a second photoresist pattern on the silicon dioxide layer, wherein the second photoresist pattern comprises a plurality of spaced photoresist convex columns, and the photoresist convex columns and the grooves are periodically staggered and arranged:

[0089] S510. Coating a positive photoresist on the silicon dioxide layer, and forming the second photoresist pattern by exposing, developing or imprinting the positive photoresist;

[0090] 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.

[0091] S600. Etching the sapphire substrate with the second photoresist pattern to expose the grooves, and forming a convex structure on the surface of the sapphire substrate with the silicon dioxide layer, so as to form a patterned composite substrate with the convex structure and the grooves periodically and alternately arranged on the surface, and a gap is provided between adjacent convex structures and the grooves:

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

[0093] S620. Use BCl3 / Ar mixed gas as etching gas to perform dry etching on the sapphire substrate exposed outside the groove for 4 minutes to form a patterned composite substrate with the protrusion structure and the grooves periodically and alternately arranged on the surface.

[0094] In this embodiment, the number of the photoresist protrusions and the photoresist columns are the same and are arranged in one-to-one correspondence, the midlines between the corresponding photoresist protrusions and the photoresist columns coincide, and the relative distance between adjacent photoresist columns is greater than the opening width of the grooves between adjacent photoresist columns.

[0095] In this embodiment, the depth of the groove is smaller than the height of the protruding structure.

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

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

[0098] It comprises a sapphire substrate and a silicon dioxide layer arranged on the sapphire substrate, wherein the sapphire substrate is provided with grooves, and the silicon dioxide layer comprises protruding structures, wherein the protruding structures and the grooves are periodically staggered and arranged, and intervals are arranged between adjacent protruding structures and the grooves.

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

[0100] Example 2

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

[0102] S100. Provide a sapphire substrate.

[0103] S200. Forming a first photoresist pattern on the sapphire substrate, wherein the first photoresist pattern includes a plurality of photoresist protrusions arranged at intervals:

[0104] S210. Coating a negative photoresist on the sapphire substrate, the negative photoresist is exposed, developed or embossed to form the first photoresist pattern, and 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 CHF3 / O2 mixed gas as etching gas, dry-etching the sapphire substrate with the first photoresist pattern until the first photoresist pattern is completely etched, and the sapphire substrate forms inwardly concave grooves between adjacent photoresist protrusions.

[0107] S400. Growing a silicon dioxide layer on the sapphire substrate with the groove, wherein the silicon dioxide layer fills the groove and is spread flat on the surface of the sapphire substrate.

[0108] S500. Forming a second photoresist pattern on the silicon dioxide layer, wherein the second photoresist pattern comprises a plurality of spaced photoresist convex columns, and the photoresist convex columns and the grooves are periodically staggered and arranged:

[0109] S510. Coating a positive photoresist on the silicon dioxide layer, and forming the second photoresist pattern by exposing, developing or imprinting the positive photoresist;

[0110] 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.

[0111] S600. Etching the sapphire substrate with the second photoresist pattern to expose the grooves, and forming a convex structure on the surface of the sapphire substrate with the silicon dioxide layer, so as to form a patterned composite substrate with the convex structure and the grooves periodically and alternately arranged on the surface, and a gap is provided between adjacent convex structures and the grooves:

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

[0113] In this embodiment, the number of the photoresist protrusions and the photoresist columns are the same and are arranged in one-to-one correspondence, the midlines between the corresponding photoresist protrusions and the photoresist columns coincide, and the relative distance between adjacent photoresist columns is greater than the opening width of the grooves between adjacent photoresist columns.

[0114] In this embodiment, the depth of the groove is smaller than the height of the protruding structure.

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

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

[0117] It comprises a sapphire substrate and a silicon dioxide layer arranged on the sapphire substrate, wherein the sapphire substrate is provided with grooves, and the silicon dioxide layer comprises protruding structures, wherein the protruding structures and the grooves are periodically staggered and arranged, and intervals are arranged between adjacent protruding structures and the grooves.

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

[0119] Comparative Example 1

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

[0121] S11. Providing a sapphire substrate;

[0122] S12. Growing a SiO2 layer on the sapphire substrate;

[0123] S13. Apply a first photoresist on the SiO2 layer and form a plurality of first photoresist columns by developing and exposing;

[0124] S14. dry etching the sapphire substrate with the first photoresist column to form a plurality of protruding structures on the SiO2 layer;

[0125] S15. Coating a second photoresist on the sapphire substrate with a plurality of protrusions, and forming a plurality of second photoresist columns by developing and exposing, and making the bottom width of the second photoresist column greater than the corresponding protrusion structure;

[0126] S16. Dry-etching the sapphire substrate with the second photoresist column to form grooves between adjacent protruding structures, so as to form a patterned composite substrate with protruding structures and grooves periodically and alternately arranged on the surface, and intervals are provided between adjacent protruding structures and grooves.

[0127] Comparative Example 2

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

[0129] S21. Providing a sapphire substrate;

[0130] S22. Growing a SiO2 layer on the sapphire substrate;

[0131] S23. Apply a first photoresist on the SiO2 layer and form a plurality of first photoresist columns by developing and exposing;

[0132] S24. Dry etching the sapphire substrate with the first photoresist column to form a plurality of protruding structures on the SiO2 layer;

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

[0134] S26. Etching in a buffered oxide etchant to form a gap between the adjacent protrusion structure and the groove;

[0135] S27. The substrate in the previous step is dry-etched with a mixed gas of boron trichloride and tetrafluoromethane to form a patterned composite substrate with raised structures and grooves periodically and alternately arranged on the surface, and intervals are provided between adjacent raised structures and grooves.

[0136] Experimental test:

[0137] 1. Test objects: Example 1 to Example 2 and Comparative Example 1 to Comparative Example 2;

[0138] 2. Test 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 conduct photoelectric performance tests to test their 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] The experimental results show that the patterned composite substrates prepared by the preparation method of the present invention in Examples 1 and 2 are clearer, and have better brightness and antistatic ability than Comparative Examples 1 and 2. Among them, Example 1 has better performance, while the patterns of Comparative Examples 1 and 2 have local deformation, and the brightness and antistatic ability are poor. The reason may be that in Comparative Example 1, photoresist is filled in the grooves, and it is difficult to ensure uniform coating of the photoresist, which affects the clarity of subsequent patterns, and the photoresist is difficult to remove cleanly. Comparative Example 2 adopts a wet process, and it is difficult to better control the shape trend of the surface morphology.

[0145] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the field can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A method for preparing a patterned composite substrate, characterized in that: include: 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 groove, wherein the silicon dioxide layer fills the groove and is spread on 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 spaced photoresist convex columns, and the photoresist convex columns and the grooves are periodically staggered; The sapphire substrate with the second photoresist pattern is etched to expose the grooves and to form a protruding structure on the surface of the sapphire substrate with the silicon dioxide layer, so as to form a patterned composite substrate with the protruding structures and the grooves periodically and alternately arranged on the surface, and with gaps between adjacent protruding structures and the grooves.

2. The method for preparing a patterned composite substrate according to claim 1, characterized in that: The step of forming a first photoresist pattern on the sapphire substrate comprises: A negative photoresist is coated on the sapphire substrate, and the negative photoresist is exposed, developed or embossed to form the first photoresist pattern, and the viscosity of the negative photoresist is 36 cP to 56 cP.

3. The method for preparing a patterned composite substrate according to claim 2, characterized in that: The step of forming a second photoresist pattern on the silicon dioxide layer comprises: Coating a positive photoresist on the silicon dioxide layer, and forming the second photoresist pattern by exposing, developing or embossing the positive photoresist; 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.

4. The method for preparing a patterned composite substrate according to claim 1, characterized in that: The step of etching the sapphire substrate with the first photoresist pattern comprises: Using CHF3 / O2 mixed gas as etching gas, dry etching the sapphire substrate with the first photoresist pattern until the first photoresist pattern is completely etched and a groove prototype that is inwardly concave is formed between adjacent photoresist protrusions on the sapphire substrate; The sapphire substrate with the groove prototype is dry-etched using a BCl3 / Ar mixed gas as an etching gas for 5 minutes to 20 minutes to form the sapphire substrate with the groove.

5. The method for preparing a patterned composite substrate according to claim 1, characterized in that: The step of etching the sapphire substrate with the second photoresist pattern comprises: Using a CHF3 / O2 mixed gas as an etching gas, dry etching the sapphire substrate with the second photoresist pattern until the groove is exposed; BCl3 / Ar mixed gas is used as etching gas to perform dry etching on the sapphire substrate with the groove exposed, and the etching process lasts for 4 to 6 minutes to form a patterned composite substrate with the protrusion structure and the grooves periodically and alternately arranged on the surface.

6. The method for preparing a patterned composite substrate according to claim 1, characterized in that: The number of the photoresist protrusions and the photoresist convex columns are the same and they are arranged in one-to-one correspondence, the midlines between the corresponding photoresist protrusions and the photoresist convex columns coincide, and the relative distance between adjacent photoresist convex columns is greater than the opening width of the grooves between adjacent photoresist convex columns.

7. The method for preparing a patterned composite substrate according to claim 1, characterized in that: The depth of the groove is smaller than the height of the protruding 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, and filling the groove with the silicon dioxide layer and spreading it on the surface of the sapphire substrate, the depth of the groove: 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 to 8; It comprises a sapphire substrate and a silicon dioxide layer arranged on the sapphire substrate, wherein the sapphire substrate is provided with grooves, and the silicon dioxide layer comprises protruding structures, wherein the protruding structures and the grooves are periodically staggered and arranged, and intervals are arranged between adjacent protruding structures and the grooves.

10. An LED chip, characterized in that: Comprising the patterned composite substrate according to claim 9.

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