Bending-resistant aluminum oxide multilayer ceramic substrate and preparation method thereof

Abstract

The invention relates to the technical field of ceramic substrates, and provides a bending-resistant aluminum oxide multilayer ceramic substrate and a preparation method thereof. The bending-resistant aluminum oxide multilayer ceramic substrate comprises the following raw material components in parts by weight: 95-110 parts of aluminum oxide, 3-8 parts of a plasticizer, 6-12 parts of an auxiliary agent, 4-7 parts of a binder, 3-6 parts of a dispersant and 60-70 parts of a solvent, the preparation method of the additive comprises the following steps: A1, adding calcium oxide into ethanol, adding glucose, stirring until the materials are uniformly mixed, and concentrating to obtain a glucose coated material; a2, carrying out annealing treatment on the glucose coated material to obtain a carbon coated material; and A3, uniformly mixing the carbon-coated material with magnesium oxide and titanium dioxide, and carrying out ball milling to obtain the auxiliary agent. According to the technical scheme, the problem of low mechanical property of the aluminum oxide ceramic substrate in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic substrates, and specifically, to a bending-resistant alumina multi-layer ceramic substrate and a preparation method thereof. Background Art

[0002] In the fields of electronic packaging and energy devices, the reliability of alumina multi-layer ceramic substrates directly affects the performance of high-end electronic devices, and the selection of sintering aids is the key to determining the quality of the substrates. Although traditional aids such as magnesium oxide and calcium oxide can promote sintering densification, their ability to improve the mechanical properties of ceramic substrates is limited. The main reasons are as follows: ① Calcium oxide is prone to absorb moisture and deteriorate, and it will also introduce moisture to interfere with the sintering process, resulting in insufficient sintering densification and insufficient grain boundary bonding force; ② Magnesium oxide reacts with alumina at high temperatures to form magnesium aluminate spinel. This phase has good chemical compatibility with the alumina matrix and high structural stability. The uniform distribution of its nanoscale particles at the grain boundaries can effectively hinder abnormal grain growth and become the key to regulating the microstructure of the substrate. However, the formation rate of spinel is difficult to control. Summary of the Invention

[0003] The present invention provides a bending-resistant alumina multi-layer ceramic substrate and a preparation method thereof, which solve the problem of low mechanical properties of alumina ceramic substrates in related technologies.

[0004] The technical solution of the present invention is as follows: The present invention provides a bending-resistant alumina multi-layer ceramic substrate, and the raw materials include the following components in parts by weight: 95-110 parts of alumina, 3-8 parts of plasticizer, 6-12 parts of aid, 4-7 parts of binder, 3-6 parts of dispersant, and 60-70 parts of solvent; The preparation method of the aid includes the following steps: A1. Add calcium oxide to ethanol, add glucose, stir until evenly mixed, and concentrate to obtain a glucose-coated material; A2. Anneal the glucose-coated material to obtain a carbon-coated material; A3. Mix the carbon-coated material with magnesium oxide and titanium dioxide evenly and then ball mill to obtain the aid.

[0005] In the bending-resistant alumina multi-layer ceramic substrate of the present invention, the plasticizer can weaken the intermolecular interaction force. For polymer components such as binders, the addition of the plasticizer reduces the viscosity of the system, makes the slurry have better fluidity, and is convenient for tape casting. At the same time, the plasticizer can improve the flexibility of the green body and reduce defects such as cracks caused by brittleness in the subsequent processing process.

[0006] In the anti-bending alumina multi-layer ceramic substrate of the present invention, the binder molecules contain a large number of polar groups such as hydroxyl groups. In the raw material system of the ceramic substrate, these polar groups can form interactions with the active sites on the surface of particles such as alumina, firmly bonding the ceramic particles together. During the tape casting process, the binder imparts certain viscosity and plasticity to the slurry, enabling it to form a green body with certain strength and shape stability. In the subsequent sintering process, the binder decomposes at high temperature and does not have an adverse effect on the final properties of the ceramic substrate.

[0007] In the anti-bending alumina multi-layer ceramic substrate of the present invention, the dispersant evenly disperses the particles in the ceramic slurry, improving the stability and fluidity of the slurry, facilitating the tape casting process, and ensuring the quality uniformity of the green body.

[0008] As a further technical solution, the mass-volume ratio of calcium oxide to ethanol is 1 g: 20 - 22 mL.

[0009] As a further technical solution, the mass ratio of magnesium oxide to calcium oxide is 13: 7 - 8; The mass ratio of the calcium oxide to the glucose is 8 - 9: 1; The mass ratio of the carbon-coated material to titanium dioxide is 5 - 6: 1.

[0010] In the anti-bending alumina multi-layer ceramic substrate of the present invention, the mass ratio of magnesium oxide to calcium oxide can be 13: 7, 13: 7.1, 13: 7.2, 13: 7.3, 13: 7.4, 13: 7.5, 13: 7.6, 13: 7.7, 13: 7.8, 13: 7.9, 13: 8, and is preferably 13: 8.

[0011] In the anti-bending alumina multi-layer ceramic substrate of the present invention, the mass ratio of the carbon-coated material to titanium dioxide can be 5: 1, 5.1: 1, 5.2: 1, 5.3: 1, 5.4: 1, 5.5: 1, 5.6: 1, 5.7: 1, 5.8: 1, 5.9: 1, 6: 1.

[0012] In the anti-bending alumina multi-layer ceramic substrate of the present invention, when the mass ratio of the carbon-coated material to titanium dioxide is in the range of 5 - 6: 1, it can ensure the uniform distribution of titanium dioxide on the surface of carbon-coated calcium oxide and give full play to its role. During the sintering process, the uniformly distributed titanium dioxide can more efficiently catalyze the formation of spinel. As an important crystal phase, the amount and distribution state of spinel have a key impact on the microstructure and properties of the alumina multi-layer ceramic substrate. The spinel formed under the appropriate ratio, in synergy with the carbon-coated structure, further optimizes the grain boundary structure and the bonding force between grains inside the ceramic substrate, thereby significantly improving the bending strength of the alumina multi-layer ceramic substrate, enabling it to withstand greater external forces in practical applications and reducing the risk of cracking and damage.

[0013] As a further technical solution, the temperature of the annealing treatment is 450-560°C, the time is 6-7 h, and the atmosphere is argon; The rotation speed of the ball milling is 500-600 rpm, and the time is 3-5 h.

[0014] As a further technical solution, the particle size of the calcium oxide is 1-10 μm, and the particle sizes of the magnesium oxide and titanium dioxide are independently 100-200 nm.

[0015] As a further technical solution, the particle size of the calcium oxide is 10 μm, and the particle sizes of the magnesium oxide and titanium dioxide are independently 100 nm.

[0016] In the anti-bending alumina multi-layer ceramic substrate of the present invention, the particle size of the calcium oxide is in the range of 1-10 μm. During the forming process of the ceramic substrate, the larger particle size makes the calcium oxide distribute relatively uniformly and stably in the system, and it is not easy to agglomerate. It also ensures the uniformity of the formation of the carbon-coated structure, enhances the protection of the calcium oxide, and reduces the performance deterioration caused by moisture absorption. The particle sizes of the magnesium oxide and titanium dioxide are in the range of 100-200 nm, which has a large specific surface area, enabling the titanium dioxide to better exert its catalytic activity. When compounded with the carbon-coated calcium oxide, the small particle sizes of the magnesium oxide and titanium dioxide can fully and uniformly adhere to its surface. During the sintering process, the highly active titanium dioxide effectively catalyzes the formation of magnesium aluminate spinel. Moreover, the specific particle size combination of the magnesium oxide, calcium oxide, and titanium dioxide produces a synergistic effect. The stable structure constructed by the larger particle size of the calcium oxide provides a good support and dispersion basis for the magnesium oxide and titanium dioxide, enabling the titanium dioxide to fully play its role in catalyzing and refining the grains. The refined grains by the titanium dioxide and the magnesium aluminate spinel formed by promoting the formation of magnesium oxide and alumina further optimize the microstructure, and synergistically improve the fracture toughness of the anti-bending alumina multi-layer ceramic substrate.

[0017] As a further technical solution, the plasticizer includes one of dibutyl phthalate and dinonyl phthalate.

[0018] As a further technical solution, the binder includes one of polyvinyl butyral and polyvinyl alcohol.

[0019] As a further technical solution, the dispersant includes one of sodium polyacrylate and polyethylene glycol.

[0020] As a further technical solution, the solvent includes one or more of n-butanol, isopropanol, and ethanol.

[0021] The present invention also provides a method for preparing a bend-resistant alumina multi-layer ceramic substrate for preparing the bend-resistant alumina multi-layer ceramic substrate, comprising the following steps: S1. Mix alumina, a plasticizer, an auxiliary agent, a dispersant, and a solvent uniformly, and then add a binder to obtain a slurry; S2. Cast and form the slurry, and dry it to obtain a green body; S3. Punch holes in the green body, and perform surface printing, lamination, vertical and horizontal conduction, cutting, sintering, and cooling to obtain the bend-resistant alumina multi-layer ceramic substrate.

[0022] The working principle and beneficial effects of the present invention are as follows: In the present invention, magnesium oxide, calcium oxide, glucose, and titanium dioxide are used together to prepare an auxiliary agent and added to the alumina multi-layer ceramic substrate, significantly improving the bending strength of the alumina multi-layer ceramic substrate. The reason is that after the surface of calcium oxide is coated with a carbon layer, direct contact between calcium oxide and water is avoided, improving the stability of calcium oxide. Moreover, after coating with the carbon layer and compounding with magnesium oxide and titanium dioxide, titanium dioxide on the carbon layer catalyzes the formation of magnesium aluminate spinel during the sintering process. The two mechanisms act synergistically, greatly improving the bending strength of the alumina multi-layer ceramic substrate. Specific Embodiments

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of the present invention.

[0024] In the following embodiments and comparative examples, the particle size of alumina is 1 μm, the weight average molecular weight of polyvinyl butyral is 30,000, the weight average molecular weight of polyethylene glycol is 4,000, and the model is PEG4000.

[0025] Example 1 A bend-resistant alumina multi-layer ceramic substrate, the raw materials of which include the following components in parts by weight: 110 parts of alumina, 8 parts of dibutyl phthalate, 12 parts of an auxiliary agent, 7 parts of polyvinyl butyral, 6 parts of polyethylene glycol, 35 parts of n-butanol, and 35 parts of isopropanol; The preparation method of the auxiliary agent comprises the following steps: A1. Add calcium oxide with a particle size of 1 μm to ethanol, add glucose (the mass-volume ratio of calcium oxide to ethanol is 1 g:20 mL, and the mass ratio of calcium oxide to glucose is 9:1), stir until evenly mixed, and concentrate to obtain a glucose-coated material; A2. Anneal the glucose-coated material (hold at 560 °C for 6 h in an argon atmosphere) to obtain a carbon-coated material; A3. Mix the carbon-coated material with magnesium oxide having a particle size of 100 nm and titanium dioxide having a particle size of 1 μm (the mass ratio of magnesium oxide to calcium oxide is 13:8, and the mass ratio of the carbon-coated material to titanium dioxide is 8:1), and then ball-mill the mixture at a speed of 600 rpm for 3 h to obtain an additive; A method for preparing a bend-resistant alumina multi-layer ceramic substrate, comprising the following steps: S1. Mix alumina, dibutyl phthalate, an additive, polyethylene glycol, n-butanol, and isopropanol evenly, and then add polyvinyl butyral to obtain a slurry; S2. Cast the slurry into a film, dry it to obtain a green body; S3. Punch the green body, perform surface printing, lamination, upper and lower conduction, cutting, sinter at 1700 °C for 5 h, and cool to obtain a bend-resistant alumina multi-layer ceramic substrate; The raw material for surface printing is tungsten paste, and the printing thickness is 15 μm; The number of layers of the multi-layer ceramic substrate is 30.

[0026] Example 2 A bend-resistant alumina multi-layer ceramic substrate, the raw materials of which include the following components in parts by weight: 95 parts of alumina, 3 parts of dinonyl phthalate, 6 parts of an additive, 4 parts of polyvinyl butyral, 3 parts of polyethylene glycol, and 60 parts of ethanol; The preparation method of the additive comprises the following steps: A1. Add calcium oxide having a particle size of 10 μm to ethanol, add glucose (the mass-volume ratio of calcium oxide to ethanol is 1 g:22 mL, and the mass ratio of calcium oxide to glucose is 8:1), stir until evenly mixed, and concentrate to obtain a glucose-coated material; A2. Anneal the glucose-coated material (hold at 450 °C for 7 h in an argon atmosphere) to obtain a carbon-coated material; A3. Mix the carbon-coated material with magnesium oxide having a particle size of 100 nm and titanium dioxide having a particle size of 1 μm (the mass ratio of magnesium oxide to calcium oxide is 13:7, and the mass ratio of the carbon-coated material to titanium dioxide is 4:1), and then ball-mill the mixture at a speed of 500 rpm for 5 h to obtain an additive; A method for preparing a bend-resistant alumina multi-layer ceramic substrate, comprising the following steps: S1. Mix alumina, dinonyl phthalate, an additive, polyethylene glycol, and ethanol evenly, and then add polyvinyl butyral to obtain a slurry; S2. Cast the slurry into a film, dry it to obtain a green body; S3. Punch holes in the blank material, followed by surface printing, lamination, vertical and horizontal conduction, cutting, sintering at 1700 °C for 5 h, and cooling to obtain a bend-resistant alumina multi-layer ceramic substrate; The raw material for surface printing is tungsten paste, and the printing thickness is 15 μm; The number of layers of the multi-layer ceramic substrate is 30.

[0027] Example 3 The difference between this example and Example 2 is only that the mass ratio of the carbon-coated material to titanium dioxide with a particle size of 1 μm in this example is 7:1.

[0028] Example 4 The difference between this example and Example 2 is only that the mass ratio of the carbon-coated material to titanium dioxide with a particle size of 1 μm in this example is 5:1.

[0029] Example 5 The difference between this example and Example 2 is only that the mass ratio of the carbon-coated material to titanium dioxide with a particle size of 1 μm in this example is 6:1.

[0030] Example 6 The difference between this example and Example 5 is only that the particle size of titanium dioxide in this example is 50 nm.

[0031] Example 7 The difference between this example and Example 5 is only that the particle size of titanium dioxide in this example is 100 nm.

[0032] Example 8 The difference between this example and Example 5 is only that the particle size of titanium dioxide in this example is 200 nm.

[0033] Comparative Example 1 The difference between this comparative example and Example 2 is only that the preparation method of the additive in this comparative example includes the following steps: A1. Add calcium oxide with a particle size of 10 μm to ethanol, add glucose (the mass-volume ratio of calcium oxide to ethanol is 1 g:22 mL, and the mass ratio of calcium oxide to glucose is 8:1), stir until evenly mixed, and concentrate to obtain a glucose-coated material; A2. Anneal the glucose-coated material (keep it at 450 °C for 7 h, and the atmosphere is argon) to obtain a carbon-coated material; A3. Mix the carbon-coated material evenly with magnesium oxide with a particle size of 100 nm (the mass ratio of magnesium oxide to calcium oxide is 13:7), and ball-mill at a speed of 500 rpm for 5 h to obtain the additive.

[0034] Comparative Example 2 The difference between this comparative example and Example 2 is only that the preparation method of the additive in this comparative example includes the following steps: Magnesium oxide with a particle size of 100 nm, calcium oxide with a particle size of 10 μm, and titanium dioxide with a particle size of 1 μm were mixed evenly in a mass ratio of 13:7:1.75 and then ball-milled at a speed of 500 rpm for 5 h to obtain an additive.

[0035] Comparative Example 3 The difference between this comparative example and Example 2 is only that the additive in this comparative example includes magnesium oxide with a particle size of 100 nm and calcium oxide with a particle size of 10 μm in a mass ratio of 13:7.

[0036] Experimental Example 1 The bending strength of the anti-bending alumina multi-layer ceramic substrates prepared in Examples 1 to 5 and Comparative Examples 1 to 3 was tested according to the test method specified in GB / T 6569-2006 "Test Method for Bending Strength of Fine Ceramics". The test method was three-point bending. The test results are shown in Table 1.

[0037] Table 1 Test Results of Bending Strength

[0038] As can be seen from Table 1, the bending strength of the anti-bending alumina multi-layer ceramic substrates prepared in Examples 1 to 5 of the present invention reached more than 427 MPa. Therefore, in the present invention, after carbon coating calcium oxide and then compounding it with magnesium oxide and titanium dioxide, the bending strength of the alumina multi-layer ceramic substrate was improved.

[0039] Experimental Example 2 The fracture toughness of the anti-bending alumina multi-layer ceramic substrates prepared in Examples 5 to 8 was tested according to the method specified in GB / T 23806-2009 "Test Method for Fracture Toughness of Fine Ceramics - Single Edge Pre-Cracked Beam (SEPB) Method". The test method was three-point bending. The test results are shown in Table 2.

[0040] Table 2 Test Results of Fracture Toughness

[0041] As can be seen from Table 2, the fracture toughness of the anti-bending alumina multi-layer ceramic substrates prepared in Examples 7 to 8 of the present invention reached 5.02 MPa / m 2 Above, therefore, the present invention selects magnesium oxide, calcium oxide with a particle size of 1 - 10 μm and titanium dioxide with a particle size of 100 - 200 nm for compounding, which improves the fracture toughness of the anti-bending alumina multi-layer ceramic substrate.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bend-resistant alumina multi-layer ceramic substrate, characterized in that, The raw materials include the following components in parts by weight: 95 - 110 parts of alumina, 3 - 8 parts of plasticizer, 6 - 12 parts of auxiliary agent, 4 - 7 parts of binder, 3 - 6 parts of dispersant, and 60 - 70 parts of solvent; The preparation method of the auxiliary agent includes the following steps: A1. Add calcium oxide to ethanol, add glucose, stir until evenly mixed, and concentrate to obtain a glucose-coated material; A2. Anneal the glucose-coated material to obtain a carbon-coated material; A3. Mix the carbon-coated material with magnesium oxide and titanium dioxide evenly and then ball-mill to obtain the auxiliary agent.

2. The anti-bending alumina multi-layer ceramic substrate according to claim 1, wherein The mass ratio of the magnesium oxide to the calcium oxide is 13:7 - 8; The mass ratio of the calcium oxide to the glucose is 8 - 9:1; The mass ratio of the carbon-coated material to the titanium dioxide is 5 - 6:

1.

3. The anti-bending alumina multi-layer ceramic substrate according to claim 1, wherein The temperature of the annealing treatment is 450 - 560 °C, the time is 6 - 7 h, and the atmosphere is argon; The rotation speed of the ball-milling is 500 - 600 rpm, and the time is 3 - 5 h.

4. The anti-bending alumina multi-layer ceramic substrate according to claim 1, wherein The particle size of the calcium oxide is 1 - 10 μm, and the particle sizes of the magnesium oxide and the titanium dioxide are independently 100 - 200 nm.

5. The anti-bending alumina multi-layer ceramic substrate according to claim 4, characterized in that, The particle size of the calcium oxide is 10 μm, and the particle sizes of the magnesium oxide and the titanium dioxide are independently 100 nm.

6. The anti-bending alumina multi-layer ceramic substrate according to claim 1, characterized in that, The plasticizer includes one of dibutyl phthalate and dinonyl phthalate.

7. The anti-bending alumina multi-layer ceramic substrate according to claim 1, characterized in that The binder includes one of polyvinyl butyral and polyvinyl alcohol.

8. The anti-bending alumina multi-layer ceramic substrate according to claim 1, characterized in that, The dispersant includes one of sodium polyacrylate and polyethylene glycol.

9. The anti-bending alumina multi-layer ceramic substrate according to claim 1, wherein The solvent includes one or more of n-butanol, isopropanol, and ethanol.

10. A method for preparing a bend-resistant alumina multi-layer ceramic substrate for preparing the bend-resistant alumina multi-layer ceramic substrate according to any one of claims 1 to 9, characterized in that, It includes the following steps: S1. Mix alumina, plasticizer, auxiliary agent, dispersant, and solvent evenly, and then add the binder to obtain a slurry; S2. Cast and form the slurry, and dry it to obtain a green body; S3. Punch holes in the green body, and through surface printing, lamination, vertical conduction, cutting, sintering, and cooling, obtain the anti-bending alumina multi-layer ceramic substrate.

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