High thermal conductivity aluminum nitride ceramic substrate for high power integrated circuit and method for manufacturing the same

Abstract

The application relates to the technical field of ceramic substrates, and discloses a high-thermal-conductivity aluminum nitride ceramic substrate for high-power integrated circuits and a preparation method thereof. The high-thermal-conductivity aluminum nitride ceramic substrate for high-power integrated circuits comprises the following components by weight: 80-100 parts of aluminum nitride, 10-15 parts of a composite additive, 5-10 parts of a sintering additive, 10-15 parts of a binder, 1-3 parts of a dispersing agent, 2-4 parts of a plasticizer and 50-60 parts of a solvent. The composite additive comprises the following components by weight: 100 parts of silicon carbide, 2-3 parts of chloropropyl trimethoxysilane, 1-2 parts of an emulsifier, 0.1-0.3 parts of an initiator, 1-2 parts of sodium acrylate and 6-10 parts of 2-ethoxyethyl sodium acrylate. The above technical scheme solves the problem of low thermal conductivity of the aluminum nitride ceramic substrate in the related art.

Description

Technical Field

[0001] This invention relates to the field of ceramic substrate technology, and more specifically, to a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits and its preparation method. Background Technology

[0002] With the rapid development of industries such as 5G communication, cloud computing, artificial intelligence, and new energy vehicles, high-power integrated circuits are constantly evolving towards high-density integration, high current carrying capacity, and high-frequency operation. However, this high-power operation mode causes chips to generate a large amount of heat during operation. If the heat cannot be dissipated in time, the junction temperature will rise, thereby affecting the chip's performance, operational stability, and long-term lifespan. As a key link in the chip's heat dissipation path, the packaging substrate not only needs to support the chip and provide electrical interconnections for the circuit, but also undertakes the core task of quickly transferring the heat generated by the chip to the heat dissipation system. Therefore, in the field of high-power integrated circuit packaging, higher requirements are placed on the thermal conductivity of the substrate material.

[0003] Currently, aluminum nitride ceramics are considered an ideal material for high-power integrated circuit packaging substrates due to their high theoretical thermal conductivity and low dielectric constant. However, in practical applications, to further improve the thermal conductivity of aluminum nitride ceramic substrates, silicon carbide, which has higher thermal conductivity, is often added to the aluminum nitride matrix to construct an efficient thermally conductive network. However, silicon carbide particles have high surface energy and are prone to agglomeration, making it difficult to achieve uniform dispersion when directly mixed into the aluminum nitride matrix. The presence of agglomerates not only fails to effectively utilize the thermal conductivity advantages of silicon carbide but also forms structural defects and pores during sintering, increasing interfacial thermal resistance and ultimately resulting in limited improvement in the substrate's thermal conductivity. Therefore, developing a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits is of great significance. Summary of the Invention

[0004] This invention proposes a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits and its preparation method, which solves the problem of low thermal conductivity of aluminum nitride ceramic substrates in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits, comprising the following raw materials in parts by weight: 80-100 parts aluminum nitride, 10-15 parts composite additives, 5-10 parts sintering aids, 10-15 parts binder, 1-3 parts dispersant, 2-4 parts plasticizer, and 50-60 parts solvent. The composite additive comprises the following raw materials in parts by weight: 100 parts silicon carbide, 2-3 parts chloropropyltrimethoxysilane, 1-2 parts emulsifier, 0.1-0.3 parts initiator, 1-2 parts sodium acrylate, and 6-10 parts sodium 2-ethoxyethyl acrylate.

[0006] As a further technical solution, the preparation method of the composite additive includes the following steps: A1. After dispersing silicon carbide evenly in a solvent, add chloropropyltrimethoxysilane and mix. After filtration and drying, pretreated silicon carbide is obtained. A2. After mixing the emulsifier with water, add the pretreated silicon carbide and mix evenly to obtain a premixed solution; A3. Sodium acrylate, initiator and sodium 2-ethoxyethyl acrylate are added sequentially to the premixed liquid and mixed. The mixture is then filtered and dried to obtain the composite additive.

[0007] This invention first modifies silicon carbide by adding chloropropyltrimethoxysilane to obtain pretreated silicon carbide, which further improves the dispersibility of silicon carbide and thus further improves the thermal conductivity of aluminum nitride ceramic substrate. Chloropropyltrimethoxysilane can form covalent bonds with hydroxyl groups on the surface of silicon carbide, which can effectively prevent the agglomeration of silicon carbide. This allows the pretreated silicon carbide particles to achieve more uniform dispersion in the subsequent mixing process with emulsifier and water, as well as in the final mixing process with aluminum nitride matrix, thereby effectively improving the thermal conductivity of aluminum nitride ceramic substrate.

[0008] As a further technical solution, in step A1, the mixing temperature is 30~40℃ and the mixing time is 1~2h.

[0009] As a further technical solution, in step A1, the solvent is composed of anhydrous ethanol and water in a mass ratio of 6:4.

[0010] As a further technical solution, in step A3, the mixing temperature is 80~90℃ and the mixing time is 3~4h.

[0011] As a further technical solution, in step A3, the initiator is azobisisobutyramidine hydrochloride.

[0012] As a further technical solution, in step A2, the emulsifier is octylphenol polyoxyethylene ether.

[0013] As a further technical solution, the sintering aid includes yttrium oxide, hafnium dioxide, and aluminum powder.

[0014] In this invention, the flexural strength of aluminum nitride ceramic substrates is improved by adding yttrium oxide, hafnium dioxide, and aluminum powder as sintering aids. During high-temperature sintering, yttrium oxide reacts with alumina impurities on the aluminum nitride surface to form a yttrium aluminum garnet liquid phase. This liquid phase fills the pores between aluminum nitride particles, increasing the density of the ceramic substrate and thus enhancing its flexural strength. The introduction of hafnium dioxide works synergistically with yttrium oxide to promote grain growth and optimize grain boundary structure, reducing stress concentration caused by grain boundary defects and further improving flexural strength. At the sintering temperature, aluminum powder reacts with oxygen impurities, effectively reducing the oxygen content in the aluminum nitride lattice, decreasing lattice defects and microcracks, and thus enhancing the material's mechanical properties. The synergistic effect of these three agents results in a low-defect lattice, high density, and optimized grain boundary structure in the aluminum nitride ceramic substrate during sintering, effectively improving its flexural strength.

[0015] As a further technical solution, the mass ratio of yttrium oxide, hafnium dioxide and aluminum powder is 5:3:1~3.

[0016] As a further technical solution, the adhesive includes one or both of polyvinyl butyral and polyvinylpyrrolidone.

[0017] As a further technical solution, the dispersant includes one or both of dibutyl phosphate and triethyl phosphate.

[0018] As a further technical solution, the plasticizer includes one or more of butyl benzyl phthalate, dimethyl phthalate, and polyethylene glycol.

[0019] As a further technical solution, the solvent includes one or more of ethanol, isopropanol, and ethyl acetate.

[0020] This invention also proposes a method for preparing a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits, comprising the following steps: S1. Mix the raw materials evenly to obtain a slurry; S2. The slurry is cast and dried to obtain a blank. S3. The blank material is debonded and sintered to obtain a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits.

[0021] As a further technical solution, the sintering temperature is 1650~1750℃, and the sintering time is 2~4h.

[0022] As a further technical solution, the sintering atmosphere is nitrogen.

[0023] The working principle and beneficial effects of this invention are as follows: This invention improves the thermal conductivity of aluminum nitride ceramic substrates for high-power integrated circuits by adding sodium acrylate and sodium 2-ethoxyethyl acrylate to a silicon carbide surface via emulsion polymerization to obtain a composite additive. The reason for this is that while silicon carbide itself has excellent thermal conductivity, it is prone to agglomeration and difficult to achieve uniform dispersion in the aluminum nitride matrix, thus hindering the full utilization of its thermal conductivity. This invention utilizes sodium acrylate and sodium 2-ethoxyethyl acrylate for emulsion polymerization on the silicon carbide surface, effectively improving the dispersibility of silicon carbide in the aluminum nitride ceramic matrix, thereby further enhancing the thermal conductivity of the aluminum nitride ceramic substrates for high-power integrated circuits. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In the following examples and comparative examples: aluminum nitride, average particle size: 5 μm; silicon carbide, average particle size: 50 nm; yttrium oxide, average particle size: 1 μm; hafnium dioxide, average particle size: 2 μm; aluminum powder, average particle size: 1 μm; polyvinyl butyral: butyral content 76 wt%, hydroxyl content 14 wt%, viscosity 100 cps; octylphenol polyoxyethylene ether is octylphenol polyoxyethylene (10) ether.

[0026] Example 1 A method for fabricating a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits includes the following steps: S1. Mix 80 parts aluminum nitride, 10 parts composite additive, 5 parts sintering aid, 10 parts polyvinyl butyral, 1 part dibutyl phosphate, 2 parts butyl benzyl phthalate, and 50 parts ethanol evenly to obtain a slurry; wherein the sintering aid is yttrium oxide. S2. The slurry is cast and dried to obtain a blank material; S3. The blank is debonded and sintered under vacuum to obtain a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits; wherein the sintering temperature is 1650℃, the sintering time is 2h, and the atmosphere is nitrogen. The composite additive comprises the following raw materials in parts by weight: 100 parts silicon carbide, 2 parts chloropropyltrimethoxysilane, 1 part octylphenol polyoxyethylene ether, 0.1 parts azobisisobutyramidine hydrochloride, 1 part sodium acrylate, and 6 parts 2-ethoxyethyl acrylate. The preparation method of the composite additive includes the following steps: A1. After dispersing silicon carbide evenly in a solvent, chloropropyltrimethoxysilane is added and mixed at 30°C for 2 hours. After filtration and drying, pretreated silicon carbide is obtained. The mass-volume ratio of silicon carbide to solvent is 1g:10mL, and the solvent is composed of anhydrous ethanol and water in a mass ratio of 6:4. A2. Add octylphenol polyoxyethylene ether to water (mass ratio of octylphenol polyoxyethylene ether to water is 1:100) and mix for 3 hours. Then add pretreated silicon carbide and mix for 1 hour to obtain a premixed solution. A3. Sodium acrylate, azobisisobutyramidine hydrochloride and 2-ethoxyethyl sodium acrylate are added sequentially to the premix solution and mixed at 80°C for 4 hours. After filtration and drying, the composite additive is obtained.

[0027] Example 2 A method for fabricating a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits includes the following steps: S1. Mix 90 parts aluminum nitride, 12 parts composite additive, 8 parts sintering aid, 13 parts polyvinyl butyral, 2 parts dibutyl phosphate, 3 parts butyl benzyl phthalate, and 55 parts ethanol evenly to obtain a slurry; wherein the sintering aid is yttrium oxide. S2. The slurry is cast and dried to obtain a blank material; S3. The blank is debonded and sintered under vacuum to obtain a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits; wherein the sintering temperature is 1700℃, the sintering time is 3h, and the atmosphere is nitrogen. The composite additive comprises the following raw materials in parts by weight: 100 parts silicon carbide, 2 parts chloropropyltrimethoxysilane, 1 part octylphenol polyoxyethylene ether, 0.1 parts azobisisobutyramidine hydrochloride, 1 part sodium acrylate, and 6 parts 2-ethoxyethyl acrylate. The preparation method of the composite additive includes the following steps: A1. After dispersing silicon carbide evenly in a solvent, chloropropyltrimethoxysilane is added and mixed at 35°C for 1.5 h. After filtration and drying, pretreated silicon carbide is obtained. The mass-volume ratio of silicon carbide to solvent is 1 g: 10 mL, and the solvent is composed of anhydrous ethanol and water in a mass ratio of 6:4. A2. Add octylphenol polyoxyethylene ether to water (mass ratio of octylphenol polyoxyethylene ether to water is 1:100) and mix for 3.5 h, then add pretreated silicon carbide and mix for 1.5 h to obtain a premixed solution. A3. Sodium acrylate, azobisisobutyramidine hydrochloride and 2-ethoxyethyl sodium acrylate are added sequentially to the premix solution and mixed at 85°C for 3.5 h. After filtration and drying, the composite additive is obtained.

[0028] Example 3 A method for fabricating a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits includes the following steps: S1. Mix 100 parts aluminum nitride, 15 parts composite additive, 10 parts sintering aid, 15 parts polyvinyl butyral, 3 parts dibutyl phosphate, 4 parts butyl benzyl phthalate, and 60 parts ethanol evenly to obtain a slurry; wherein the sintering aid is yttrium oxide. S2. The slurry is cast and dried to obtain a blank material; S3. The blank is debonded and sintered under vacuum to obtain a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits; wherein the sintering temperature is 1750℃, the sintering time is 2h, and the atmosphere is nitrogen. The composite additive comprises the following raw materials in parts by weight: 100 parts silicon carbide, 2 parts chloropropyltrimethoxysilane, 1 part octylphenol polyoxyethylene ether, 0.1 parts azobisisobutyramidine hydrochloride, 1 part sodium acrylate, and 6 parts 2-ethoxyethyl acrylate. The preparation method of the composite additive includes the following steps: A1. After dispersing silicon carbide evenly in a solvent, chloropropyltrimethoxysilane is added and mixed at 40°C for 1 hour. After filtration and drying, pretreated silicon carbide is obtained. The mass-volume ratio of silicon carbide to solvent is 1 g: 10 mL, and the solvent is composed of anhydrous ethanol and water in a mass ratio of 6:4. A2. Add octylphenol polyoxyethylene ether to water (mass ratio of octylphenol polyoxyethylene ether to water is 1:100) and mix for 4 hours. Then add pretreated silicon carbide and mix for 2 hours to obtain a premixed solution. A3. Sodium acrylate, azobisisobutyramidine hydrochloride and 2-ethoxyethyl sodium acrylate are added sequentially to the premix solution and mixed at 90°C for 3 hours. After filtration and drying, the composite additive is obtained.

[0029] Example 4 The only difference between this embodiment and Embodiment 2 is that the composite additive in this embodiment includes the following raw materials in parts by weight: 100 parts silicon carbide, 2.5 parts chloropropyltrimethoxysilane, 1.5 parts octylphenol polyoxyethylene ether, 0.2 parts azobisisobutyramidine hydrochloride, 1.5 parts sodium acrylate, and 8 parts 2-ethoxyethyl acrylate.

[0030] Example 5 The only difference between this embodiment and Embodiment 2 is that the composite additive in this embodiment includes the following raw materials in parts by weight: 100 parts silicon carbide, 3 parts chloropropyltrimethoxysilane, 2 parts octylphenol polyoxyethylene ether, 0.3 parts azobisisobutyramidine hydrochloride, 2 parts sodium acrylate, and 10 parts 2-ethoxyethyl acrylate.

[0031] Example 6 The only difference between this embodiment and Embodiment 2 is that the sintering aid in this embodiment is composed of yttrium oxide, hafnium dioxide and aluminum powder in a mass ratio of 5:3:1.

[0032] Example 7 The only difference between this embodiment and Embodiment 6 is that the sintering aid in this embodiment is composed of yttrium oxide, hafnium dioxide and aluminum powder in a mass ratio of 5:3:2.

[0033] Example 8 The only difference between this embodiment and Embodiment 6 is that the sintering aid in this embodiment is composed of yttrium oxide, hafnium dioxide and aluminum powder in a mass ratio of 5:3:3.

[0034] Example 9 The only difference between this embodiment and Embodiment 6 is that the sintering aid in this embodiment is composed of yttrium oxide and hafnium dioxide in a mass ratio of 5:3.

[0035] Example 10 The only difference between this embodiment and Embodiment 6 is that the sintering aid in this embodiment is composed of yttrium oxide and aluminum powder in a mass ratio of 5:1.

[0036] Example 11 The only difference between this embodiment and Embodiment 6 is that the sintering aid in this embodiment is composed of hafnium dioxide and aluminum powder in a mass ratio of 3:1.

[0037] Comparative Example 1 The only difference between this comparative example and Example 2 is that the composite additive in this comparative example is silicon carbide.

[0038] Comparative Example 2 The only difference between this comparative example and Example 2 is that the composite additive in this comparative example includes the following raw materials in parts by weight: 100 parts of silicon carbide, 1 part of octylphenol polyoxyethylene ether, 0.1 parts of azobisisobutyramidine hydrochloride, 1 part of sodium acrylate, and 6 parts of sodium 2-ethoxyethyl acrylate. The preparation method of the composite additive includes the following steps: A1. Add octylphenol polyoxyethylene ether to water (mass ratio of octylphenol polyoxyethylene ether to water is 1:100) and mix for 3.5 hours, then add silicon carbide and mix for 1.5 hours to obtain a premixed solution. A3. Sodium acrylate, azobisisobutyramidine hydrochloride and 2-ethoxyethyl sodium acrylate are added sequentially to the premix solution and mixed at 85°C for 3.5 h. After filtration and drying, the composite additive is obtained.

[0039] Comparative Example 3 The composite additive comprises the following raw materials in parts by weight: 100 parts silicon carbide, 2 parts chloropropyltrimethoxysilane, 1 part octylphenol polyoxyethylene ether, 0.1 parts azobisisobutyramidine hydrochloride, 1 part sodium acrylate, and 6 parts sodium methyl methacrylate. The preparation method of the composite additive includes the following steps: A1. After dispersing silicon carbide evenly in a solvent, chloropropyltrimethoxysilane is added and mixed at 35°C for 1.5 h. After filtration and drying, pretreated silicon carbide is obtained. The mass-volume ratio of silicon carbide to solvent is 1 g: 10 mL, and the solvent is composed of anhydrous ethanol and water in a mass ratio of 6:4. A2. Add octylphenol polyoxyethylene ether to water (mass ratio of octylphenol polyoxyethylene ether to water is 1:100) and mix for 3.5 h, then add pretreated silicon carbide and mix for 1.5 h to obtain a premixed solution. A3. Sodium acrylate, azobisisobutyramidine hydrochloride and sodium methyl methacrylate are added sequentially to the premix solution and mixed at 85°C for 3.5 h. After filtration and drying, the composite additive is obtained.

[0040] Experimental Example 1 The high thermal conductivity aluminum nitride ceramic substrates for high-power integrated circuits prepared in Examples 1-5 and Comparative Examples 1-3 were tested according to the following method: Thermal conductivity: The thermal conductivity of the aluminum nitride ceramic substrate was determined according to the test method specified in standard GB / T 39862-2021 "Test of thermal conductivity of high thermal conductivity ceramics". The test results are shown in Table 1 below.

[0041] Table 1 Performance test results of aluminum nitride ceramic substrates for high-power integrated circuits prepared in Examples 1-5 and Comparative Examples 1-3

[0042] As shown in Table 1, the thermal conductivity of Examples 1-5 is higher than that of Comparative Examples 1-3, indicating that the present invention provides the thermal conductivity of aluminum nitride ceramic substrates for high-power integrated circuits by using sodium acrylate and 2-ethoxyethyl sodium acrylate as composite additives through emulsion polymerization on the silicon carbide surface.

[0043] Experimental Example 2 The high thermal conductivity aluminum nitride ceramic substrates for high-power integrated circuits prepared in Examples 2 and 6-11 were tested according to the following method: Bending strength: in accordance with standard GB / T 6569 The bending strength of aluminum nitride ceramic substrates was measured by the three-point bending test according to the 2006 standard "Test Method for Bending Strength of Fine Ceramics". The test results are shown in Table 2 below.

[0044] Table 2 Performance test results of aluminum nitride ceramic substrates for high-power integrated circuits prepared in Examples 2, 6-11

[0045] As shown in Table 2, the bending strength of Examples 6-8 is higher than that of Examples 2 and Examples 9-11, indicating that the present invention improves the bending strength of aluminum nitride ceramic substrates for high-power integrated circuits by adding yttrium oxide, hafnium dioxide and aluminum powder as sintering aids.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits, characterized in that, Raw materials comprising the following components by weight: 80-100 parts aluminum nitride, 10-15 parts composite additives, 5-10 parts sintering aids, 10-15 parts binder, 1-3 parts dispersant, 2-4 parts plasticizer, and 50-60 parts solvent; The composite additive comprises the following raw material parts by weight: 100 parts silicon carbide, 2-3 parts chloropropyltrimethoxysilane, 1-2 parts emulsifier, 0.1-0.3 parts initiator, 1-2 parts sodium acrylate, and 6-10 parts sodium 2-ethoxyethyl acrylate.

2. The high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits according to claim 1, characterized in that, The preparation method of the composite additive includes the following steps: A1. After dispersing silicon carbide evenly in a solvent, add chloropropyltrimethoxysilane and mix. After filtration and drying, pretreated silicon carbide is obtained. A2. After mixing the emulsifier with water, add the pretreated silicon carbide and mix evenly to obtain a premixed solution; A3. Sodium acrylate, azobisisobutyramidine hydrochloride and 2-ethoxyethyl sodium acrylate are added sequentially to the premixed solution and mixed. The mixture is then filtered and dried to obtain the composite additive.

3. The high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits according to claim 2, characterized in that, In step A1, the mixing temperature is 30~40℃ and the mixing time is 1~2h.

4. The high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits according to claim 2, characterized in that, In step A3, the mixing temperature is 80~90℃ and the mixing time is 3~4h.

5. The high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits according to claim 1, characterized in that, The sintering aids include yttrium oxide, hafnium dioxide, and aluminum powder.

6. The high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits according to claim 5, characterized in that, The mass ratio of yttrium oxide, hafnium dioxide, and aluminum powder is 5:3:1~3.

7. The high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits according to claim 1, characterized in that, The adhesive includes one or both of polyvinyl butyral and polyvinylpyrrolidone.

8. The high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits according to claim 1, characterized in that, The solvent includes one or more of ethanol, isopropanol, and ethyl acetate.

9. A method for preparing a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits, used to prepare the aluminum nitride ceramic substrate as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Mix the raw materials evenly to obtain a slurry; S2. The slurry is cast and dried to obtain a blank. S3. The blank material is debonded and sintered to obtain a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits.

10. The method for preparing a high thermal conductivity aluminum nitride ceramic substrate for high-power integrated circuits according to claim 9, characterized in that, The sintering temperature is 1650~1750℃, and the sintering time is 2~4h.

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