High-heat-conductivity multilayer ceramic substrate and preparation method thereof

Abstract

The invention relates to the technical field of ceramic substrates, and provides a high-heat-conductivity multilayer ceramic substrate and a preparation method thereof. The high-thermal-conductivity multilayer ceramic substrate comprises the following raw materials in parts by weight: 80-90 parts of aluminum oxide, 10-15 parts of modified silicon carbide, 5-10 parts of a sintering aid, 3-7 parts of a binder, 5-10 parts of a toughening aid and 60-70 parts of water, wherein the modified silicon carbide is obtained by modifying silicon carbide with 2-amino-5-methyl benzoate. According to the technical scheme, the problem of low heat conductivity of the ceramic substrate in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic substrate, in particular, relates to high thermal conductivity multilayer ceramic substrate and preparation method thereof. BACKGROUND

[0002] With the rapid development of 5G communication, new energy vehicles, power electronics and other fields, electronic devices evolve towards high integration and high power density, and the heat generated during operation increases sharply, so efficient heat dissipation becomes the core requirement to ensure the stability and life of the device. As a key material for electronic packaging, ceramic substrate is widely used in power modules, LED heat dissipation substrates, radio frequency antennas and other scenarios due to its excellent insulation, high temperature resistance and mechanical properties. Among them, high thermal conductivity ceramic substrate is the key to determine the heat dissipation efficiency of the device, which directly affects the operation reliability of the electronic system. However, the most widely used alumina ceramic substrate on the market has low thermal conductivity, which is difficult to meet the heat dissipation needs of high-power devices, resulting in an increase in device operating temperature. Not only will it cause performance degradation, but it may also cause interface cracking between the substrate and the chip, metal layer due to thermal stress accumulation, and even cause safety hazards such as circuit short circuit and device burnout, which restricts the further development of high-end electronic equipment. Therefore, it is necessary to propose a high thermal conductivity multilayer ceramic substrate and a preparation method thereof. SUMMARY

[0003] The present application proposes a high thermal conductivity multilayer ceramic substrate and a preparation method thereof, which solves the problem of low thermal conductivity of the ceramic substrate in the related art.

[0004] The technical scheme of the present application is as follows: The present application proposes a high thermal conductivity multilayer ceramic substrate, which comprises the following components by weight: 80-90 parts of alumina, 10-15 parts of modified silicon carbide, 5-10 parts of sintering aid, 3-7 parts of binder, 5-10 parts of toughening aid, and 60-70 parts of water; the modified silicon carbide is obtained by modifying silicon carbide with 2-amino-5-methylbenzoic acid methyl ester.

[0005] As a further technical solution, the particle size of the silicon carbide is 40-60 nm.

[0006] As a further technical solution, the mass of 2-amino-5-methylbenzoic acid methyl ester in the modified silicon carbide is 3-5% of the mass of silicon carbide, preferably 4.3%.

[0007] As a further technical solution, the preparation method of the modified silicon carbide comprises the following steps: dispersing 2-amino-5-methylbenzoic acid methyl ester in a solution, then adding silicon carbide, mixing, drying, and obtaining modified silicon carbide.

[0008] As a further technical solution, the temperature of the mixing is 40-50 DEG C, and the mixing time is 3h.

[0009] As a further technical solution, the solution is anhydrous ethanol.

[0010] As a further technical solution, the mass-volume ratio of the silicon carbide and the anhydrous ethanol is 1g:9mL.

[0011] As a further technical solution, the toughening aid includes zirconium oxide, tin oxide and samarium oxide.

[0012] In the high-thermal-conductivity multilayer ceramic substrate, by adding the toughening aid composed of zirconium oxide, tin oxide and samarium oxide, the fracture toughness of the multilayer ceramic substrate can be further improved: when subjected to external force, zirconium oxide will undergo a martensitic phase transition from tetragonal phase to monoclinic phase, and the volume expansion generated in the phase transition process can form microcracks inside the ceramic substrate, which can effectively disperse and consume external impact or stress energy, avoiding the rapid expansion of the main crack, thereby significantly improving the toughness of the high-thermal-conductivity multilayer ceramic substrate; but when zirconium oxide is used alone, its volume change accompanying the phase transition is not controlled, which is easy to cause internal stress concentration in the sintering or stress process of the ceramic substrate, and then cause cracking; and samarium oxide and tin oxide can form a stable solid solution with zirconium oxide, which can effectively relieve the internal stress generated by volume change and reduce the risk of cracking, thereby further improving the fracture toughness of the high-thermal-conductivity multilayer ceramic substrate.

[0013] As a further technical solution, the mass ratio of zirconium oxide, tin oxide and samarium oxide in the toughening aid is 10-14:4:3, for example, it can be 10:4:3, 11:4:3, 13:4:3, 14:4:3, and preferably 11:4:3.

[0014] In the high-thermal-conductivity multilayer ceramic substrate, when the mass ratio of zirconium oxide, tin oxide and samarium oxide in the toughening aid is 10-14:4:3, tin oxide and samarium oxide can form a solid solution with zirconium oxide, which can effectively toughen while reducing the cracking risk caused by the volume change of zirconium oxide phase transition, thereby further improving the fracture toughness of the high-thermal-conductivity multilayer ceramic substrate.

[0015] As a further technical solution, the crystal form of the zirconium oxide is tetragonal phase, and the particle size is 400-600nm.

[0016] The crystal form of the zirconium oxide in the toughening aid of the high-thermal-conductivity multilayer ceramic substrate is tetragonal phase, so that the phase change toughening effect can be better played. In addition, when the particle size of the zirconium oxide is less than 400 nm, the zirconium oxide is easy to agglomerate and difficult to uniformly disperse in the aluminum oxide matrix, so that the phase change toughening effect cannot be well realized. When the particle size of the zirconium oxide is greater than 600 nm, the interface bonding area between the zirconium oxide particles and the aluminum oxide matrix is relatively reduced, so that micro pores or gaps are easy to form at the interface between the particles and the matrix during the sintering process, and the fracture toughness of the ceramic substrate is reduced. When the crystal form of the zirconium oxide is tetragonal phase and the particle size of the zirconium oxide is 400-600 nm, the phase change toughening effect can be better played, so that the fracture toughness of the high-thermal-conductivity multilayer ceramic substrate is improved.

[0017] As a further technical solution, the binder comprises one or more of polyvinyl alcohol, carboxymethyl cellulose and hydroxyethyl cellulose.

[0018] As a further technical solution, the sintering aid comprises one or both of calcium oxide and magnesium oxide.

[0019] The application further provides a preparation method of the high-thermal-conductivity multilayer ceramic substrate, comprising the following steps: S1, uniformly mixing aluminum oxide, modified silicon carbide, a sintering aid, a toughening aid and water, and then adding a binder to obtain a slurry; S2, performing flow casting on the slurry and drying to obtain a green body; S3, perforating the green body, performing surface printing, lamination, up-down conduction, cutting, sintering and cooling to obtain the high-thermal-conductivity multilayer ceramic substrate.

[0020] As a further technical solution, in step S3, the sintering temperature is 1300-1400 DEG C, for example, can be 1300 DEG C, 1350 DEG C, 1400 DEG C, and is preferably 1350 DEG C.

[0021] As a further technical solution, in step S3, the sintering time is 30-60 min, for example, can be 30 min, 40 min, 45 min or 60 min, and the sintering atmosphere is nitrogen.

[0022] The working principle and beneficial effects of the application are as follows: The present application effectively improves the thermal conductivity of the alumina multilayer ceramic substrate by adding silicon carbide modified by methyl 2-amino-5-methylbenzoate. In the prior art, in order to improve the thermal conductivity of the alumina ceramic substrate, a filler with high thermal conductivity such as silicon carbide is usually added to enhance the overall thermal conductivity of the ceramic substrate. However, due to the easy agglomeration of silicon carbide, it is difficult to achieve uniform dispersion in the alumina matrix, resulting in the failure of the thermal conductive filler to fully play its role. To solve this problem, the present application uses methyl 2-amino-5-methylbenzoate to modify the surface of silicon carbide, which significantly improves its dispersibility in the alumina ceramic matrix, and further improves the thermal conductivity of the alumina multilayer ceramic substrate. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] In the following examples and comparative examples, the particle size of the alumina is 20 μm; the particle size of the silicon carbide is 50 nm; the particle size of the magnesium oxide is 40 nm; the particle size of the calcium oxide is 18 μm; the type of polyvinyl alcohol is PVA-1788; the crystal form of the zirconium oxide is tetragonal phase, and the particle size is 500 nm; the particle size of the tin oxide is 50 nm; the particle size of the samarium oxide is 1 μm.

[0025] Example 1 The preparation method of the high-thermal-conductivity multilayer ceramic substrate comprises the following steps: S1, uniformly mix 80 parts of alumina, 10 parts of modified silicon carbide, 5 parts of magnesium oxide, 5 parts of toughening aid, and 60 parts of water, then add 3 parts of polyvinyl alcohol to obtain a slurry; S2, perform flow casting of the slurry, dry to obtain a green body; S3, perforate the green body, perform surface printing, layering (20 layers), up-down conduction, cutting, sintering, and cooling to obtain a high-thermal-conductivity multilayer ceramic substrate; wherein the sintering temperature is 1350℃, the time is 45 min, and the atmosphere is nitrogen; The toughening aid is only zirconium oxide; The preparation method of the modified silicon carbide comprises the following steps: dispersing methyl 2-amino-5-methylbenzoate in anhydrous ethanol, then adding silicon carbide, mixing at 45℃ for 3h, and drying to obtain modified silicon carbide; wherein the mass of methyl 2-amino-5-methylbenzoate is 3% of the mass of silicon carbide, and the mass-volume ratio of silicon carbide to anhydrous ethanol is 1g:9mL.

[0026] Example 2 The difference between Example 2 and Example 1 is only that the preparation method of the high-thermal-conductivity multilayer ceramic substrate in the present example comprises the following steps: S1, 85 parts of alumina, 13 parts of modified silicon carbide, 7 parts of calcium oxide, 8 parts of toughening aid, 65 parts of water are uniformly mixed, and then 5 parts of hydroxyethyl cellulose is added to obtain a slurry; S2, the slurry is subjected to flow casting molding and drying to obtain a green body; S3, the green body is perforated, and surface printing, layering (20 layers), up and down conduction, cutting, sintering and cooling are performed to obtain a high-thermal-conductivity multilayer ceramic substrate; wherein the sintering temperature is 1350°C, the time is 45 min, and the atmosphere is nitrogen.

[0027] Example 3 The difference between Example 3 and Example 1 is only that the preparation method of the high-thermal-conductivity multilayer ceramic substrate in the present example comprises the following steps: S1, 90 parts of alumina, 15 parts of modified silicon carbide, 5 parts of calcium oxide, 5 parts of magnesium oxide, 10 parts of toughening aid, and 70 parts of water are uniformly mixed, and then 7 parts of carboxymethyl cellulose is added to obtain a slurry; S2, the slurry is subjected to flow casting molding and drying to obtain a green body; S3, the green body is perforated, and surface printing, layering (20 layers), up and down conduction, cutting, sintering and cooling are performed to obtain a high-thermal-conductivity multilayer ceramic substrate; wherein the sintering temperature is 1350°C, the time is 45 min, and the atmosphere is nitrogen.

[0028] Example 4 The difference between Example 4 and Example 1 is only that the mass of 2-amino-5-methylbenzoic acid methyl ester in the modified silicon carbide in the present example is 4.3% of the mass of the silicon carbide.

[0029] Example 5 The difference between Example 5 and Example 1 is only that the mass of 2-amino-5-methylbenzoic acid methyl ester in the modified silicon carbide in the present example is 5% of the mass of the silicon carbide.

[0030] Example 6 The difference between Example 6 and Example 1 is only that the toughening aid in the present example is composed of zirconium oxide and tin oxide with a mass ratio of 10:4.

[0031] Example 7 The difference between Example 7 and Example 1 is only that the toughening aid in the present example is composed of zirconium oxide and samarium oxide with a mass ratio of 10:3.

[0032] Example 8 The difference between Example 8 and Example 1 is only that the toughening aid in this example is composed of zirconium oxide, tin oxide and samarium oxide with a mass ratio of 10:4:3.

[0033] Example 9 The difference between Example 9 and Example 1 is only that the toughening aid in this example is composed of zirconium oxide, tin oxide and samarium oxide with a mass ratio of 11:4:3.

[0034] Example 10 The difference between Example 10 and Example 1 is only that the toughening aid in this example is composed of zirconium oxide, tin oxide and samarium oxide with a mass ratio of 14:4:3.

[0035] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is only that the modified silicon carbide in this comparative example is replaced by an equal amount of silicon carbide.

[0036] The high-thermal-conductivity multilayer ceramic substrates prepared in Examples 1-10 and Comparative Example 1 are tested according to the following method: 1. Thermal conductivity test: The thermal conductivity of the multilayer ceramic substrate is tested according to the test method specified in the standard GB / T 39862-2021 “Detection of High Thermal Conductivity Ceramic Thermal Conductivity”. 2. Fracture toughness test: The fracture toughness test is performed according to the test method specified in the standard GB / T 23806-2009 “Fine Ceramic Fracture Toughness Test Method Single Edge Pre-cracked Beam (SEPB) Method”. The test results are shown in Tables 1-2: Table 1 Thermal conductivity test results of high-thermal-conductivity multilayer ceramic substrates

[0037] As can be seen from the data in Table 1, the thermal conductivity of the multilayer ceramic substrates in Examples 1-5 is higher than that of Comparative Example 1, indicating that the addition of modified silicon carbide can significantly improve the thermal conductivity of high-thermal-conductivity multilayer ceramic substrates.

[0038] Table 2 Fracture toughness test results of high-thermal-conductivity multilayer ceramic substrates

[0039] As can be seen from the data in Table 2, the fracture toughness of the multilayer ceramic substrates in Examples 8-10 is higher than that of Examples 1, 6-7, indicating that the addition of the toughening aid composed of zirconium oxide, tin oxide and samarium oxide can significantly improve the fracture toughness of high-thermal-conductivity multilayer ceramic substrates.

[0040] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high thermal conductivity multilayer ceramic substrate, characterized in that, The raw material comprises the following components in parts by weight: 80-90 parts alumina, 10-15 parts modified silicon carbide, 5-10 parts sintering aid, 3-7 parts binder, 5-10 parts toughening aid, and 60-70 parts water; wherein the modified silicon carbide is obtained by modifying silicon carbide with methyl 2-amino-5-methylbenzoate.

2. The high thermal conductivity multilayer ceramic substrate according to claim 1, characterized in that, The mass of methyl 2-amino-5-methylbenzoate in the modified silicon carbide is 3% to 5% of the mass of silicon carbide.

3. The high thermal conductivity multilayer ceramic substrate according to claim 1, characterized in that, The method for preparing the modified silicon carbide includes the following steps: dispersing methyl 2-amino-5-methylbenzoate in a solution, then adding silicon carbide, mixing, and drying to obtain modified silicon carbide.

4. The high thermal conductivity multilayer ceramic substrate according to claim 1, characterized in that, The toughening agents include zirconium oxide, tin oxide, and samarium oxide.

5. The high thermal conductivity multilayer ceramic substrate according to claim 4, characterized in that, The toughening agent contains zirconium oxide, tin oxide and samarium oxide in a mass ratio of 10~14:4:

3.

6. The high thermal conductivity multilayer ceramic substrate according to claim 4, characterized in that, The zirconium oxide has a tetragonal crystal structure and a particle size of 400~600 nm.

7. The high thermal conductivity multilayer ceramic substrate according to claim 1, characterized in that, The adhesive includes one or more of polyvinyl alcohol, carboxymethyl cellulose, and hydroxyethyl cellulose.

8. The high thermal conductivity multilayer ceramic substrate according to claim 1, characterized in that, The sintering aids include one or both of calcium oxide and magnesium oxide.

9. A method for preparing a high thermal conductivity multilayer ceramic substrate, used to prepare the high thermal conductivity multilayer ceramic substrate as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Mix alumina, modified silicon carbide, sintering aid, toughening aid, and water evenly, then add binder to obtain slurry; S2. The slurry is cast and dried to obtain a blank. S3. The blank material is punched, and then subjected to surface printing, lamination, top and bottom conduction, cutting, sintering and cooling to obtain a high thermal conductivity multilayer ceramic substrate.

10. The method for preparing a high thermal conductivity multilayer ceramic substrate according to claim 9, characterized in that, In step S3, the sintering temperature is 1300~1400℃.

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