High-power LED device based on AlN ceramic substrate composite diamond film substrate and preparation method of high-power LED device

Abstract

The invention belongs to the technical field of LED devices, and particularly relates to a high-power LED device based on an AlN ceramic substrate and a composite diamond film substrate and a preparation method of the high-power LED device. The high-power LED device comprises a substrate, a patterned electrode formed on the surface of the substrate and an LED lamp bead connected with the patterned electrode. The substrate comprises an AlN ceramic substrate and a diamond film formed on the surface of the AlN ceramic substrate; the patterned electrode is formed on the surface of the diamond film of the substrate; the patterned electrode comprises a first electrode, a second electrode and a third electrode, the first electrode and the third electrode are symmetrically distributed with the second electrode as the center, the inner sides, close to the second electrode, of the first electrode and the third electrode are distributed in a surrounding mode with the second electrode as the center, and the two ends of the first electrode and the two ends of the third electrode are not connected. The outer sides, away from the second electrode, of the first electrode and the third electrode are each independently provided with two spaced grooves. The high-power LED device provided by the invention has good heat dissipation performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of LED devices, and particularly relates to a high-power LED device based on an AlN ceramic substrate composite diamond thin film substrate and a preparation method thereof. Background Art

[0002] With the development of LED devices towards high density and high power, a large amount of heat is generated during the operation of the chip. Research shows that only 20% - 30% of the input power of the LED chip can be converted into light energy, while the remaining 70% - 80% of the power is dissipated in the form of heat. If the heat generated during the operation of the LED device cannot be discharged in time, it will lead to the accumulation of heat inside the chip, the increase of the junction temperature of the LED device, and then affect the luminous efficiency, luminous flux and service life of the LED. Therefore, as an important part of the thermal management system of high-power LED devices, the heat dissipation performance of the heat dissipation substrate largely determines the overall effect and service life of the LED.

[0003] Currently, traditional substrates include aluminum substrates and aluminum nitride (AlN) ceramic substrates. Aluminum substrates have the advantages of low cost and easy processing, but their thermal conductivity is relatively poor and their electrical insulation is not good, which limits their application in high-power electronic devices. Although AlN ceramic substrates have good thermal conductivity and electrical insulation, their thermal conductivity is prone to decrease at high temperatures, and their thermal expansion coefficient does not match that of the LED chip material, which is prone to cause thermal stress. Therefore, these two traditional substrates cannot fully meet the heat dissipation requirements of high-power LED devices. Summary of the Invention

[0004] The first object of the present invention is to provide a high-power LED device based on an AlN ceramic substrate composite diamond thin film substrate for the problem that the existing high-power LED devices have poor heat dissipation performance, resulting in low luminous efficiency and short service life. Through the design of the composite substrate structure and the electrode with a specific pattern, the heat dissipation performance of the high-power LED device is significantly improved, meeting the heat dissipation requirements of the high-power LED device.

[0005] Specifically, the high-power LED device comprises a substrate (1), a patterned electrode (2) formed on the surface of the substrate (1), and an LED lamp bead (3) connected to the patterned electrode (2); the substrate (1) comprises an AlN ceramic substrate (11) and a diamond film (12) formed on the surface of the AlN ceramic substrate (11); the patterned electrode (2) is formed on the surface of the diamond film (12) of the substrate (1); the patterned electrode (2) comprises a first electrode (21), a second electrode (22), and a third electrode (23), wherein the first electrode (21) and the third electrode (23) are 3) are symmetrically distributed around the second electrode (21), the first electrode (21) and the third electrode (23) are arranged around the second electrode (21) near the inner side of the second electrode (21), and the two ends of the first electrode (21) and the third electrode (23) are not connected to each other, and the outer sides of the first electrode (21) and the third electrode (23) facing away from the second electrode (21) are independently provided with two spaced groove shapes; the heat sink of the LED lamp bead (3) is connected to the second electrode (22), and the pins (31) of the LED lamp bead (3) are respectively connected to the first electrode (21) and the third electrode (23).

[0006] In a preferred embodiment, the thickness of the diamond film (12) is 300-600 μm.

[0007] In a preferred embodiment, the patterned electrode (2) comprises Cr, Pt, and Au metal layers.

[0008] In a preferred embodiment, the heat sink of the LED lamp bead (3) is connected to the second electrode (22) via silicone grease, and the pin (31) of the LED lamp bead (3) is respectively connected to the first electrode (21) and the third electrode (23) via soldering.

[0009] A second object of the present invention is to provide a method for preparing a high-power LED device.

[0010] The method for preparing the high-power LED device comprises the following steps:

[0011] S1. A diamond film is grown on the surface of an AlN ceramic substrate by chemical vapor deposition and in-situ annealing in an MPCVD device, and the surface of the diamond film is ground and polished to obtain an AlN ceramic substrate composite diamond film substrate;

[0012] S2. Perform a surface activation treatment on the diamond film surface of the substrate obtained in step S1 in an ICP etching machine. Then, perform a photolithography treatment on the diamond film surface to obtain a photolithography pattern. Subsequently, use the photolithography pattern as a hard mask to sequentially deposit a metal conductive layer by magnetron sputtering. After removing the photoresist layer and drying, a patterned electrode is obtained on the diamond film surface. Among them, the patterned electrode includes a first electrode, a second electrode, and a third electrode;

[0013] S3. Connect the heat sink of the LED lamp bead to the second electrode of the patterned electrode through a packaging material, and electrically connect the pins of the LED lamp bead to the first electrode and the third electrode of the patterned electrode respectively.

[0014] In a preferred embodiment, in step S1, the chemical vapor deposition includes: introducing reaction gases into the growth chamber of an MPCVD device to deposit and grow on the surface of the AlN ceramic substrate, so as to grow a diamond film on the surface of the AlN ceramic substrate.

[0015] In a preferred embodiment, the reaction gases include hydrogen, a carbon source gas, and oxygen, and the carbon source gas is selected from at least one of methane, acetylene, propane, and propylene.

[0016] In a preferred embodiment, based on the total volume of the reaction gases, the concentration of the carbon source gas is 5 - 7% (v / v).

[0017] In a preferred embodiment, the flow rate of hydrogen is 500 - 800 sccm, and the flow rate of oxygen is 0.1 - 0.6 sccm.

[0018] In a preferred embodiment, the conditions for the deposition growth include: a deposition temperature of 550 - 950 °C, a deposition time of 80 - 120 h, and a microwave power of 2000 - 3000 W.

[0019] In a preferred embodiment, the conditions for the in-situ annealing treatment include: a hydrogen atmosphere, an annealing temperature of 300 - 600 °C, a heat preservation time of 1 - 2 h, and a cooling time of 1 - 3 h.

[0020] In a preferred embodiment, in step S2, the conditions for the surface activation treatment include: an inert gas flow rate of 10 - 30 sccm, an upper electrode power of 200 - 400 W, a lower electrode power of 50 - 100 W, a pressure of 0.1 - 1 Pa, and a time of 5 - 10 min.

[0021] In a preferred embodiment, the metal conductive layer includes Cr, Pt, and Au metal layers

[0022] In a preferred embodiment, the power of the magnetron sputtering is 50 - 80 W, the deposition time of the Cr metal layer is 30 - 60 s, the deposition time of the Pt metal layer is 20 - 80 s, and the deposition time of the Au metal layer is 100 - 180 s.

[0023] In a preferred embodiment, the temperature of the drying treatment is 80 - 120 °C, and the time is 30 - 45 min.

[0024] In a preferred embodiment, in step S2, the photolithography process includes: forming a photoresist layer on the surface of the diamond film, and obtaining a photolithography pattern after exposing and developing the photoresist layer through a hard mask.

[0025] In a preferred embodiment, in step S2, before the surface activation treatment of the diamond film surface of the substrate obtained in step S1, a cleaning treatment is also included; the cleaning treatment includes: sequentially placing the substrate obtained in step S1 into acetone, absolute ethanol, and deionized water for ultrasonic treatment.

[0026] In a preferred embodiment, in step S3, the encapsulating material is silicone grease.

[0027] In a preferred embodiment, the electrical connection is made by soldering.

[0028] The key of the present invention lies in designing a substrate of an AlN ceramic substrate composite diamond film with a specific structure and forming an electrode with a specific pattern on the substrate. Since the electrode pattern optimizes the current distribution and increases the heat dissipation area, it effectively improves the heat dissipation performance of the LED device. And when combined with the AlN ceramic substrate composite diamond film substrate, the electrode pattern further enhances the heat conduction path and synergistically improves the overall heat dissipation efficiency. Thus, through the mutual cooperation between the two, the obtained high-power LED device has good heat dissipation performance, significantly reduces the junction temperature and thermal resistance of the LED device, and improves the luminous efficiency and service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of a high-power LED device.

[0030] Figure 2 is a schematic plan view of a patterned electrode.

[0031] Figure 3 is a physical diagram of an LED device.

[0032] Figure 4 is a graph of the junction temperature of the high-power LED devices provided in Example 1, Comparative Example 1, and Comparative Example 2 at different current intensities.

[0033] Figure numerals: 1, substrate; 11, AlN ceramic substrate; 12, diamond film; 2, patterned electrode; 21, first electrode; 22, second electrode; 23, third electrode; 3, LED lamp bead; 31, pin. DETAILED DESCRIPTION

[0034] See also Figure 1 and Figure 2 The high-power LED device provided by the present invention comprises a substrate 1, a patterned electrode 2 formed on the surface of the substrate (1), and an LED lamp bead 3 connected to the patterned electrode 2; the substrate 1 comprises an AlN ceramic substrate 11 and a diamond film 12 formed on the surface of the AlN ceramic substrate 11; the patterned electrode 2 is formed on the surface of the diamond film 12 of the substrate 1; the patterned electrode 2 comprises a first electrode 21, a second electrode 22 and a third electrode 23, wherein the first electrode 21 and the third electrode 23 are symmetrically distributed with the second electrode 21 as the center, the first electrode 21 and the third electrode 23 are distributed around the second electrode 21 near the inner side of the second electrode 21 and the second electrode 21 as the center, and the two ends of the first electrode 21 and the third electrode 23 are not connected to each other, and the first electrode 21 and the third electrode 23 are independently provided with two spaced groove shapes on the outer side away from the second electrode 21; the heat sink of the LED lamp bead 3 is connected to the second electrode 22, and the pins 31 of the LED lamp bead 3 are respectively connected to the first electrode 21 and the third electrode 23.

[0035] In the present invention, the thickness of the diamond film 12 is preferably 300-600 μm, such as 300 μm, 326 μm, 360 μm, 400 μm, 418 μm, 450 μm, 500 μm, 550 μm, 600 μm or any value therebetween. This is more conducive to ensuring high thermal conductivity while taking into account mechanical strength and process feasibility, so that the diamond film and the AlN ceramic substrate form an efficient heat conduction interface, further improving the heat dissipation performance of the LED device.

[0036] In the present invention, the patterned electrode 2 preferably includes Cr, Pt, and Au metal layers, which is more conducive to improving the conductivity, oxidation resistance, and adhesion of the electrode, while optimizing the current distribution, enhancing the heat dissipation performance, and cooperating with the AlN ceramic substrate composite diamond film substrate to achieve efficient thermal management and improve the heat dissipation performance.

[0037] The method for preparing a high-power LED device provided by the present invention comprises the following steps:

[0038] S1. A diamond film is grown on the surface of an AlN ceramic substrate by chemical vapor deposition and in-situ annealing in an MPCVD (microwave plasma chemical vapor deposition) device, and the surface of the diamond film is ground and polished to obtain an AlN ceramic substrate composite diamond film substrate;

[0039] S2. Surface activation treatment is performed on the diamond film surface of the substrate obtained in step S1 in an ICP etcher. Then, photolithography treatment is carried out on the diamond film surface to obtain a photolithography pattern. Subsequently, a metal conductive layer is sequentially deposited by magnetron sputtering using the photolithography pattern as a hard mask. After removing the photoresist layer and drying, a patterned electrode is obtained on the diamond film surface. Among them, the patterned electrode includes a first electrode, a second electrode, and a third electrode.

[0040] S3. The heat sink of the LED lamp bead is connected to the second electrode of the patterned electrode through a packaging material, and the pins of the LED lamp bead are electrically connected to the first electrode and the third electrode of the patterned electrode respectively.

[0041] In the present invention, in step S1, the chemical vapor deposition specifically includes: in the growth chamber of an MPCVD device, reaction gases are introduced to perform deposition growth on the surface of the AlN ceramic substrate, so as to grow a diamond film on the surface of the AlN ceramic substrate.

[0042] In a specific embodiment, the reaction gases preferably include hydrogen, a carbon source gas, and oxygen, and specific examples of the carbon source gas include but are not limited to at least one of methane, acetylene, propane, and propylene.

[0043] In a specific embodiment, based on the total volume of the reaction gases, the concentration of the carbon source gas is preferably 5-7% (v / v), such as 5% (v / v), 5.5% (v / v), 6% (v / v), 6.5% (v / v), 7% (v / v), or any value between them.

[0044] In a specific embodiment, the flow rate of the hydrogen is preferably 500-800 sccm, such as 500 sccm, 600 sccm, 700 sccm, 800 sccm, or any value between them; the flow rate of the oxygen is preferably 0.1-0.6 sccm, such as 0.1 sccm, 0.2 sccm, 0.3 sccm, 0.5 sccm, 0.6 sccm, or any value between them.

[0045] In a specific embodiment, the conditions for deposition growth preferably include: the deposition temperature is 550-950 °C, such as 550 °C, 600 °C, 700 °C, 800 °C, 900 °C, 920 °C, 950 °C or any value therebetween; the deposition time is 80-120 h, such as 80 h, 90 h, 100 h, 110 h, 120 h or any value therebetween; the microwave power is 2000-3000 W, such as 2000 W, 2500 W, 3000 W or any value therebetween. At this time, it is more conducive to growing a uniform high-quality diamond film on the AlN ceramic substrate, further improving the heat dissipation performance of the LED device.

[0046] In the present invention, in step S1, the conditions for the in-situ annealing treatment preferably include: a hydrogen atmosphere, the annealing temperature is 300-600 °C, such as 300 °C, 400 °C, 500 °C, 600 °C or any value therebetween. At this time, it is more conducive to obtaining a polycrystalline diamond film with a good crystal structure, further reducing the thermal resistance of the LED device and improving the heat dissipation performance of the LED device; the heat preservation time is 1-2 h, such as 1 h, 1.2 h, 1.5 h, 1.8 h, 2 h or any value therebetween; the cooling time is 1-3 h, such as 1 h, 1.5 h, 2 h, 2.5 h, 3 h or any value therebetween.

[0047] In the present invention, in step S2, the conditions for the surface activation treatment preferably include: the flow rate of the inert gas is 10-30 sccm, such as 10 sccm, 15 sccm, 20 sccm, 22 sccm, 25 sccm, 28 sccm, 30 sccm or any value therebetween; the power of the upper electrode plate is 200-400 W, such as 200 W, 250 W, 300 W, 350 W, 380 W, 400 W or any value therebetween; the power of the lower electrode plate is 50-100 W, such as 50 W, 80 W, 90 W, 100 W or any value therebetween; the pressure is 0.1-1 Pa, such as 0.1 Pa, 0.2 Pa, 0.5 Pa, 0.8 Pa, 1 Pa or any value therebetween; the time is 5-10 min, such as 5 min, 6 min, 7 min, 8 min, 9 min, 10 min or any value therebetween.

[0048] In the present invention, in step S2, the metal conductive layer preferably includes Cr, Pt, and Au metal layers. The power of the magnetron sputtering is preferably 50 - 80 W, such as 50 W, 30 W, 70 W, 80 W, or any value therebetween; the pressure is preferably 0.5 - 1 Pa, such as 0.5 Pa, 0.6 Pa, 0.7 Pa, 0.8 Pa, 0.9 Pa, 1 Pa, or any value therebetween; the time for depositing the Cr metal layer is preferably 30 - 60 s, such as 30 s, 35 s, 40 s, 50 s, 55 s, 60 s, or any value therebetween; the time for depositing the Pt metal layer is preferably 20 - 80 s, such as 20 s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, or any value therebetween; the time for depositing the Au metal layer is preferably 100 - 180 s, such as 100 s, 120 s, 140 s, 160 s, 170 s, 180 s, or any value therebetween.

[0049] In the present invention, in step S2, the temperature of the drying treatment is preferably 80 - 120 °C, such as 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, or any value therebetween; the time is preferably 30 - 45 min, such as 30 min, 32 min, 35 min, 38 min, 40 min, 42 min, 45 min, or any value therebetween. At this time, it is more conducive to improving the bonding strength between the patterned electrode and the diamond film.

[0050] In the present invention, in step S2, the photolithography treatment preferably includes: forming a photoresist layer on the surface of the diamond film, and obtaining a photolithography pattern after exposing and developing the photoresist layer through a hard mask.

[0051] In a specific embodiment, the photolithography treatment may include: spin-coating a photoresist on the surface of the diamond film, performing a pre-baking treatment to form a photoresist layer, and then exposing, developing, and post-baking the photoresist layer through a hard mask, that is, obtaining a photolithography pattern on the surface of the diamond film.

[0052] In a specific embodiment, the temperature of the pre-baking treatment is preferably 80 - 110 °C, such as 80 °C, 90 °C, 100 °C, 105 °C, 110 °C, or any value therebetween; the time is preferably 1 - 5 min, such as 1 min, 1.5 min, 2 min, 2.5 min, 3 min, 4 min, 5 min, or any value therebetween.

[0053] In a specific embodiment, the light source for the exposure is preferably a UV lamp, and the exposure dose is preferably 100 - 500 mJ / cm 2 , such as 100 mJ / cm 2 , 200 mJ / cm 2 , 300 mJ / cm2 , 400 mJ / cm 2 , 500 mJ / cm 2 or any value therebetween; the exposure time is preferably 2 - 3 min, such as any value between 2 min, 2.5 min, and 3 min.

[0054] In a specific embodiment, the temperature of the post-baking treatment is preferably 100 - 110 °C, such as 100 °C, 102 °C, 105 °C, 108 °C, 110 °C or any value therebetween; the time is preferably 1 - 3 min, such as 1 min, 1.5 min, 2 min, 2.5 min, 3 min or any value therebetween.

[0055] In a specific embodiment, before spin-coating the photoresist, a pre-baking treatment may further be included. The temperature of the pre-baking treatment is preferably 80 - 150 °C, such as 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 150 °C or any value therebetween; the time is preferably 6 - 10 min, such as 6 min, 7 min, 8 min, 9 min, 10 min or any value therebetween.

[0056] In the present invention, in step S2, before surface activation treatment of the diamond film surface of the substrate obtained in step S1, a cleaning treatment is preferably further included. The purpose of the cleaning treatment is to remove residual contaminants on the diamond film surface. Those skilled in the art can make adaptive selections according to actual needs, and the present invention does not make special limitations.

[0057] In a specific embodiment, the cleaning treatment preferably includes: sequentially placing the substrate obtained in step S1 into acetone, absolute ethanol, and deionized water for ultrasonic treatment. More specifically, the time of the ultrasonic treatment is preferably 5 - 15 min, such as 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 12 min, 14 min, 15 min or any value therebetween; the power of the ultrasonic treatment is preferably 80 - 100 W, such as 80 W, 85 W, 90 W, 95 W, 100 W or any value therebetween.

[0058] In the present invention, in step S2, the method for removing the photoresist layer preferably includes: placing the substrate after magnetron sputtering in a stripping machine to remove the photoresist layer by oxygen plasma treatment, and then soaking it in an acetone solution for 10 - 30 min.

[0059] In the present invention, in step S3, the encapsulating material is preferably silicone grease, which can be commercially obtained or prepared by existing methods. The electrical connection is preferably made by soldering.

[0060] The present invention will be described in detail below with specific embodiments.

[0061] Example 1

[0062] S1. First, cut the AlN ceramic substrate into wafers with a diameter of 20 mm. After pretreatment (ultrasonic treatment in acetone, absolute ethanol, and deionized water in sequence for 5 min at an ultrasonic power of 150 W), place the AlN ceramic substrate in the growth chamber of the MPCVD equipment. Heat the AlN ceramic substrate to 900 °C, adjust the microwave power to 2500 W, and continuously introduce reaction gases (including hydrogen with a flow rate of 500 sccm, oxygen with a flow rate of 0.5 sccm, and methane with a flow rate of 30 sccm. The concentration of methane in the reaction gas is about 5.7% (v / v)). Deposit and grow on the surface of the AlN ceramic substrate for 80 h. Then, turn off all gases except hydrogen, perform annealing treatment at 600 °C for 2 h, and uniformly cool to room temperature within 2 h to complete the annealing treatment. After grinding and polishing the surface of the diamond film and trimming the unpolished area with laser cutting, the AlN ceramic substrate composite diamond film substrate is obtained, and the thickness of the diamond film is 326 μm;

[0063] S2. (1) Place the AlN ceramic substrate diamond film substrate obtained in S1 into acetone, absolute ethanol, and deionized water in sequence and perform ultrasonic treatment for 5 min at an ultrasonic power of 90 W. Then, dry it with nitrogen for standby. Then, place the substrate in the Genesis Micro-Nano ICP801 type ICP etching machine, introduce argon with a flow rate of 25 sccm, set the upper electrode power to 400 W, the lower electrode power to 100 W, the working pressure to 1 Pa, and the cleaning time to 7 min;

[0064] (2) Then, pre-bake the substrate at 150 °C for 10 min. After spin-coating a negative photoresist on the surface of the diamond film (spin-coating at low speed for 5 s and high speed for 30 s), perform pre-baking treatment at 105 °C for 2 min to form a photoresist layer on the surface of the diamond film. Expose the photoresist layer through a hard mask (the light source is a UV lamp, the exposure dose is 200 mJ / cm 2 , and the exposure time is 2 min). After the exposure is completed, perform post-baking treatment at 105 °C for 2 min, put it into a developer (2.38 wt% tetramethylammonium hydroxide) for development for 60 s. After the development is completed, rinse it repeatedly with deionized water and dry it with nitrogen to obtain a photolithography pattern on the surface of the diamond film;

[0065] (3) Place the substrate with the diamond film facing up on the sample stage of the magnetron sputtering coating machine. Close the chamber, evacuate to the base vacuum, introduce argon, adjust the chamber pressure to initiate glow discharge, readjust the chamber pressure to pre-sputter and clean the target, then open the baffle, and sequentially deposit Cr, Pt, and Au metal layers through the magnetron sputtering process using the lithography pattern as a hard mask. The sputtering times are 60 s, 80 s, and 180 s respectively, and the power is 80 W. Place the substrate after magnetron sputtering in a desoldering machine to remove the photoresist layer through oxygen plasma treatment, then soak it in acetone solution for 20 min, and then dry it at 80 °C for 20 min, thus obtaining a patterned electrode on the surface of the diamond film, as Figure 2 shown, where the patterned electrode includes a first electrode, a second electrode, and a third electrode;

[0066] S3. Connect the heat sink of the LED chip to the second electrode of the patterned electrode through silicone grease, and connect the pins of the LED chip to the first electrode and the third electrode of the patterned electrode through soldering, thereby obtaining a high-power LED device based on the AlN ceramic substrate composite diamond film substrate. This high-power LED device has the structures as Figure 1 and Figure 2 shown, Figure 3 which is a physical diagram of the LED device.

[0067] Example 2

[0068] S1. First, cut the AlN ceramic substrate into wafers with a diameter of 20 mm. After pretreatment (ultrasonic treatment for 5 min at an ultrasonic power of 150 W using acetone, absolute ethanol, and deionized water in sequence), place the AlN ceramic substrate in the growth chamber of the MPCVD equipment, heat the AlN ceramic substrate to 950 °C, adjust the microwave power to 2000 W, continuously introduce reaction gases (including hydrogen with a flow rate of 500 sccm, oxygen with a flow rate of 0.5 sccm, and acetylene with a flow rate of 30 sccm, and the concentration of acetylene in the reaction gases is about 5.7% (v / v)), deposit and grow on the surface of the AlN ceramic substrate for 80 h, then close all gases except hydrogen, anneal at 300 °C for 2 h, and uniformly cool to room temperature within 2 h to complete the annealing treatment. Then, grind and polish the surface of the diamond film and use laser cutting to trim the area that is not fully polished, thus obtaining an AlN ceramic substrate composite diamond film substrate, and the thickness of the diamond film is 359 μm;

[0069] S2. (1) The AlN ceramic substrate diamond thin film substrate obtained in S1 was successively placed in acetone, absolute ethanol, and deionized water and ultrasonically treated for 14 min at an ultrasonic power of 80 W, and then dried with nitrogen for standby; then the substrate was placed in a Chuangshi Micro-Nano ICP801 type ICP etching machine, argon with a flow rate of 25 sccm was introduced, the upper electrode power was set to 200 W, the lower electrode power was 50 W, the working pressure was 1 Pa, and the cleaning time was 10 min;

[0070] (2) Then the substrate was pre-baked at 80 °C for 10 min. After spin-coating a negative photoresist on the diamond thin film surface (spin-coated at low speed for 5 s and at high speed for 30 s), it was pre-baked at 80 °C for 5 min to form a photoresist layer on the diamond thin film surface. The photoresist layer was exposed through a hard mask (the light source was a UV lamp, the exposure dose was 100 mJ / cm 2 , and the exposure time was 3 min). After the exposure was completed, it was post-baked at 110 °C for 1 min, placed in a developer (2.38 wt% tetramethylammonium hydroxide) for 60 s for development. After the development was completed, it was repeatedly rinsed with deionized water and then dried with nitrogen, and thus a photolithography pattern was obtained on the diamond thin film surface;

[0071] (3) The substrate with the completed photolithography was placed on the sample stage of a magnetron sputtering coating machine with the diamond thin film surface facing up. The cavity was closed, pumped to the base vacuum, argon was introduced, the cavity pressure was adjusted for glow discharge, and the cavity pressure was adjusted again for pre-sputtering to clean the target. Then the baffle was opened, and Cr, Pt, and Au metal layers were successively deposited by magnetron sputtering using the photolithography pattern as a hard mask. The sputtering times were 30 s, 20 s, and 100 s respectively, and the power was 80 W; the substrate after magnetron sputtering was placed in a desoldering machine to remove the photoresist layer by oxygen plasma treatment, then soaked in an acetone solution for 30 min, and then dried at 100 °C for 30 min, and thus a patterned electrode was obtained on the diamond thin film surface, as Figure 2 shown, wherein the patterned electrode includes a first electrode, a second electrode, and a third electrode;

[0072] S3. The heat sink of the LED lamp bead was connected to the second electrode of the patterned electrode through silicone grease, and the pins of the LED lamp bead were respectively connected to the first electrode and the third electrode of the patterned electrode by soldering, thereby obtaining a high-power LED device based on the AlN ceramic substrate composite diamond thin film substrate. This high-power LED device has a structure as shown in Figure 1 and Figure 2 shown.

[0073] Example 3

[0074] S1. First, cut the AlN ceramic substrate into wafers with a diameter of 20 mm. After pretreatment (ultrasonic treatment for 5 min at a power of 150 W in acetone, absolute ethanol, and deionized water in sequence), place the AlN ceramic substrate in the growth chamber of the MPCVD equipment. Heat the AlN ceramic substrate to 550 °C, adjust the microwave power to 3000 W, and continuously introduce reaction gases (including hydrogen with a flow rate of 500 sccm, oxygen with a flow rate of 0.5 sccm, and propylene with a flow rate of 35 sccm. The concentration of propylene in the reaction gas is approximately 6.6% (v / v)). Perform deposition growth on the surface of the AlN ceramic substrate for 120 h. Then, turn off all gases except hydrogen, perform annealing treatment at 350 °C for 1 h, and cool down to room temperature uniformly within 2 h to complete the annealing treatment. After grinding and polishing the surface of the diamond film and trimming the unpolished area using laser cutting, the AlN ceramic substrate composite diamond film substrate is obtained, and the thickness of the diamond film is 418 μm;

[0075] S2. (1) Place the AlN ceramic substrate diamond film substrate obtained in S1 in acetone, absolute ethanol, and deionized water in sequence, and perform ultrasonic treatment for 5 min at a power of 100 W. Then, dry it with nitrogen for standby. Then, place the substrate in the Genesis Micro-Nano ICP801 type ICP etching machine, introduce argon with a flow rate of 10 sccm, set the upper electrode power to 250 W, the lower electrode power to 100 W, the working pressure to 1 Pa, and the cleaning time to 5 min;

[0076] (2) Then, pre-bake the substrate at 100 °C for 6 min. After spin-coating a negative photoresist on the surface of the diamond film (spin-coating at low speed for 5 s and high speed for 30 s), perform pre-baking at 100 °C for 3 min to form a photoresist layer on the surface of the diamond film. Expose the photoresist layer through a hard mask (the light source is a UV lamp, the exposure dose is 400 mJ / cm 2 , and the exposure time is 2 min). After the exposure is completed, perform post-baking at 100 °C for 3 min, place it in a developer (2.38 wt% tetramethylammonium hydroxide) for 60 s for development. After the development is completed, rinse it repeatedly with deionized water and dry it with nitrogen to obtain a photolithography pattern on the surface of the diamond film;

[0077] (3) Place the substrate with the completed photolithography diamond film facing up on the sample stage of the magnetron sputtering coater. Close the chamber, pump it down to the base vacuum, introduce argon, adjust the chamber pressure to initiate glow discharge, readjust the chamber pressure to pre-sputter and clean the target, then open the baffle, and sequentially deposit Cr, Pt, and Au metal layers through the magnetron sputtering process using the photolithography pattern as a hard mask. The sputtering times are 60 s, 50 s, and 100 s respectively, and the power is 80 W. Place the substrate after magnetron sputtering in a desoldering machine to remove the photoresist layer by oxygen plasma treatment, then soak it in acetone solution for 10 min, and then dry it at 120 °C for 10 min, thus obtaining a patterned electrode on the diamond film surface, as Figure 2 shown, wherein the patterned electrode includes a first electrode, a second electrode, and a third electrode;

[0078] S3. Connect the heat sink of the LED lamp bead to the second electrode of the patterned electrode through silicone grease, and connect the pins of the LED lamp bead to the first electrode and the third electrode of the patterned electrode through soldering, thereby obtaining a high-power LED device based on an AlN ceramic substrate composite diamond film substrate. The high-power LED device has a structure as shown in Figure 1 and Figure 2 shown.

[0079] Example 4

[0080] Prepare a high-power LED device according to the method provided in Example 1, except that the deposition and growth time in step S1 is 30 h, and the other conditions are the same as those in Example 1. Thus, a high-power LED device based on an AlN ceramic substrate composite diamond film substrate is prepared. The high-power LED device has a structure as shown in Figure 1 and Figure 2 shown, and the thickness of the diamond film is 150 μm.

[0081] Example 5

[0082] Prepare a high-power LED device according to the method provided in Example 1, except that the deposition and growth time in step S1 is 150 h, and the other conditions are the same as those in Example 1. Thus, a high-power LED device based on an AlN ceramic substrate composite diamond film substrate is prepared. The high-power LED device has a structure as shown in Figure 1 and Figure 2 shown, and the thickness of the diamond film is 668 μm.

[0083] Comparative Example 1

[0084] The reference high-power LED device was prepared according to the method provided in Example 1, except that in step S1, a diamond film was not grown on the surface of the AlN ceramic substrate, and the other conditions were the same as those in Example 1. Thus, a reference high-power LED device based on the AlN ceramic substrate was prepared.

[0085] Comparative Example 2

[0086] The reference high-power LED device was prepared according to the method provided in Example 1, except that in step S1, an aluminum substrate was used instead of the AlN ceramic substrate and a diamond film was not grown on the surface of the aluminum substrate, and the other conditions were the same as those in Example 1. Thus, a reference high-power LED device based on the aluminum substrate was prepared.

[0087] Comparative Example 3

[0088] The reference high-power LED device was prepared according to the method provided in Example 1, except that in step S2(1), surface activation treatment was not performed using an ICP etching machine, and the other conditions were the same as those in Example 1. Thus, a reference high-power LED device based on the aluminum substrate was prepared.

[0089] Comparative Example 4

[0090] The reference high-power LED device was prepared according to the method provided in Example 1, except that in step S2(3), a different hard mask was used, and the resulting electrode pattern was two rectangles arranged at intervals, and the other conditions were the same as those in Example 1. Thus, a reference high-power LED device based on the aluminum substrate was prepared.

[0091] Test Example

[0092] The high-power LED devices prepared in the above examples and comparative examples were tested for thermal resistance performance and junction temperature performance according to the following methods, and the results are shown in Table 1.

[0093] (1) Junction temperature performance test: The experimental environment was 26 °C, the voltage was kept at 3 V, and a Uni-Trend Uti120S infrared imager was used to perform non-contact measurement of the junction temperature of the LED device. The temperature measurement range was -20 to 400 °C, and the accuracy was ±2 °C. The junction temperature data was obtained from the information in the infrared imaging diagram of the junction temperature of the instrument.

[0094] (2) Thermal resistance performance test: The steady-state thermal resistance test method was used. The test conditions were: the power of the LED device was 3 W, the current was 1 A, the voltage was 3 V, and the LED device was energized to reach the steady-state operating temperature. The power loss (P) and the temperature (T base ) of the lower surface of the substrate were measured. The comprehensive thermal resistance between the LED lamp bead and the substrate was calculated by the formula R = (T j - T base ) / P, where T j(Junction temperature) is taken from the highest temperature value of the infrared thermometer (taking 80% of the LED device power as a reference), T base It is obtained by measurement with a thermocouple.

[0095] Table 1

[0096] Thermal Resistance (K / W) Junction Temperature - 1.2A (°C) Thermal Resistance (K / W) Junction Temperature - 1.2A (°C) Example 1 3.9 70.0 Comparative Example 1 7.8 99.4 Example 2 3.5 67.3 Comparative Example 2 14.1 101.3 Example 3 3.1 65.6 Comparative Example 3 7.1 82.5 Example 4 6.8 80.7 Comparative Example 4 6.5 78.7 Example 5 3.2 66.2

[0097] From Figure 4 the results, it can be seen that compared with the reference high-power LED devices provided in Comparative Example 1 and Comparative Example 2, the junction temperature of the high-power LED device provided in Example 1 is the lowest, and as the current gradually increases from 0.2 A to 1.2 A, the junction temperature gap among the three gradually increases. At 1.2 A, the junction temperatures of Comparative Example 1, Comparative Example 2, and Example 1 are 99.4 °C, 101.3 °C, and 70.0 °C respectively.

[0098] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principle and purpose of the present invention.

Claims

1. A high-power LED device, characterized in that, The high-power LED device includes a substrate (1), a patterned electrode (2) formed on the surface of the substrate (1), and an LED lamp bead (3) connected to the patterned electrode (2); the substrate (1) includes an AlN ceramic substrate (11) and a diamond thin film (12) formed on the surface of the AlN ceramic substrate (11); the patterned electrode (2) is formed on the diamond thin film (12) surface of the substrate (1); the patterned electrode (2) includes a first electrode (21), a second electrode (22), and a third electrode (23), wherein the first electrode (21) and the third electrode (23) are symmetrically distributed with the second electrode (21) as the center, the inner sides of the first electrode (21) and the third electrode (23) close to the second electrode (21) are distributed in a surrounding manner with the second electrode (21) as the center and the two ends of the first electrode (21) and the third electrode (23) are not connected to each other, and two spaced groove shapes are independently provided on the outer sides of the first electrode (21) and the third electrode (23) facing away from the second electrode (21); the heat sink of the LED lamp bead (3) is connected to the second electrode (22), and the pins (31) of the LED lamp bead (3) are respectively connected to the first electrode (21) and the third electrode (23).

2. The high-power LED device according to claim 1, characterized in that, The thickness of the diamond thin film (12) is 300 to 600 μm.

3. The high-power LED device according to claim 1, characterized in that, The patterned electrode (2) includes Cr, Pt, and Au metal layers.

4. The high-power LED device according to claim 1, wherein The heat sink of the LED lamp bead (3) is connected to the second electrode (22) through silicone grease, and the pins (31) of the LED lamp bead (3) are respectively connected to the first electrode (21) and the third electrode (23) through soldering.

5. A method for preparing a high-power LED device according to any one of claims 1 to 4, characterized in that, The preparation method of the high-power LED device includes the following steps: S1. Grow a diamond thin film on the surface of the AlN ceramic substrate through chemical vapor deposition and in-situ annealing treatment in an MPCVD device. After grinding and polishing the surface of the diamond thin film, an AlN ceramic substrate composite diamond thin film substrate is obtained. S2. Perform surface activation treatment on the diamond thin film surface of the substrate obtained in step S1 in an ICP etching machine, then perform photolithography treatment on the diamond thin film surface to obtain a photolithography pattern, and then sequentially deposit a metal conductive layer by magnetron sputtering using the photolithography pattern as a hard mask. After removing the photoresist layer and drying, a patterned electrode is obtained on the diamond thin film surface, wherein the patterned electrode includes a first electrode, a second electrode, and a third electrode. S3. Connect the heat sink of the LED lamp bead to the second electrode of the patterned electrode through a packaging material, and electrically connect the pins of the LED lamp bead to the first electrode and the third electrode of the patterned electrode respectively.

6. The preparation method of the high-power LED device according to claim 5, characterized in that, In step S1, the chemical vapor deposition includes: introducing reaction gases into the growth chamber of the MPCVD device to perform deposition growth on the surface of the AlN ceramic substrate, so as to grow a diamond thin film on the surface of the AlN ceramic substrate.

7. The manufacturing method of the high-power LED device according to claim 6, characterized in that, The reaction gases include hydrogen, a carbon source gas, and oxygen, and the carbon source gas is selected from at least one of methane, acetylene, propane, and propylene. Preferably, based on the total volume of the reaction gas, the concentration of the carbon source gas is 5-7% (v / v); Preferably, the flow rate of the hydrogen gas is 500-800 sccm, and the flow rate of the oxygen gas is 0.1-0.6 sccm; Preferably, the conditions for the deposition growth include: a deposition temperature of 550-950 °C, a deposition time of 80-120 h, and a microwave power of 2000-3000 W; Preferably, the conditions for the in-situ annealing treatment include: a hydrogen atmosphere, an annealing temperature of 300-600 °C, a heat preservation time of 1-2 h, and a cooling time of 1-3 h.

8. The manufacturing method of the high-power LED device according to claim 5, characterized in that In step S2, the conditions for the surface activation treatment include: an inert gas flow rate of 10-30 sccm, an upper electrode plate power of 200-400 W, a lower electrode plate power of 50-100 W, a pressure of 0.1-1 Pa, and a time of 5-10 min; Preferably, the metal conductive layer includes Cr, Pt, and Au metal layers; Preferably, the power of the magnetron sputtering is 50-80 W, the deposition time of the Cr metal layer is 30-60 s, the deposition time of the Pt metal layer is 20-80 s, and the deposition time of the Au metal layer is 100-180 s; Preferably, the temperature of the drying treatment is 80-120 °C, and the time is 30-45 min.

9. The preparation method of the high-power LED device according to claim 5, characterized in that, In step S2, the photolithography treatment includes: forming a photoresist layer on the surface of the diamond film, and obtaining a photolithography pattern after exposing and developing the photoresist layer through a hard mask; Preferably, in step S2, before the surface activation treatment of the diamond film surface of the substrate obtained in step S1, a cleaning treatment is also included; the cleaning treatment includes: sequentially placing the substrate obtained in step S1 in acetone, absolute ethanol, and deionized water for ultrasonic treatment.

10. The manufacturing method of the high-power LED device according to claim 5, wherein, In step S3, the encapsulation material is silicone grease; Preferably, the electrical connection is made by soldering.

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