Anti-bending alumina multilayer ceramic substrate and preparation method thereof

Abstract

The present invention relates to the technical field of ceramic substrates, and proposes a bending-resistant alumina multilayer ceramic substrate and a preparation method thereof. The raw materials of the bending-resistant alumina multilayer ceramic substrate include the following 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 auxiliary agent includes the following steps: A1, adding calcium oxide to ethanol, adding glucose, stirring until the mixture is uniform, and concentrating to obtain a glucose-coated material; A2, annealing the glucose-coated material to obtain a carbon-coated material; A3, mixing the carbon-coated material with magnesium oxide and titanium dioxide, and then ball milling to obtain the auxiliary agent. The above technical solution solves the problem of low mechanical properties of alumina ceramic substrates in the related art.

Description

Technical Field

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

[0002] In the field of electronic packaging and energy devices, the reliability of alumina multilayer ceramic substrates directly affects the performance of high-end electronic devices, and the choice of sintering aids is key to determining substrate quality. While traditional additives such as magnesium oxide and calcium oxide can promote sintering densification, their ability to enhance the mechanical properties of ceramic substrates is limited. The main reasons are: ① Calcium oxide easily absorbs moisture and deteriorates, and also introduces moisture that interferes with the sintering process, resulting in insufficient sintering densification and insufficient grain boundary bonding; ② Magnesium oxide reacts with aluminum oxide at high temperatures to form magnesium-aluminum spinel, a phase with good chemical compatibility and high structural stability with the aluminum oxide matrix. The uniform distribution of its nanoparticles at the grain boundaries effectively hinders abnormal grain growth, becoming the key to regulating the substrate's microstructure. However, the rate of spinel formation is difficult to control. Summary of the Invention

[0003] The present invention provides an anti-bending alumina multilayer ceramic substrate and a preparation method thereof, which solves the problem of low mechanical properties of the alumina ceramic substrate in the related art.

[0004] The technical solutions of the present invention are as follows:

[0005] The present invention provides a bending-resistant alumina multilayer ceramic substrate, the raw materials of which 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;

[0006] The preparation method of the auxiliary agent comprises the following steps:

[0007] A1. Add calcium oxide to ethanol, add glucose, stir until the mixture is uniform, and concentrate to obtain a glucose-coated material;

[0008] A2, annealing the glucose-coated material to obtain a carbon-coated material;

[0009] A3. The carbon-coated material is uniformly mixed with magnesium oxide and titanium dioxide, and then ball-milled to obtain the auxiliary agent.

[0010] In the anti-bending alumina multilayer ceramic substrate of the present invention, the plasticizer can weaken the interaction force between molecules. For polymer components such as binders, the addition of the plasticizer reduces the viscosity of the system, making the slurry have better fluidity and facilitating tape casting. At the same time, the plasticizer can improve the flexibility of the blank and reduce defects such as cracks caused by brittleness during subsequent processing.

[0011] In the anti-bending alumina multilayer ceramic substrate of the present invention, the binder molecules contain a large number of polar groups such as hydroxyl groups. In the ceramic substrate raw material system, these polar groups can interact 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 a certain viscosity and plasticity to the slurry, enabling it to form a blank with a certain strength and shape stability. In the subsequent sintering process, the binder decomposes at high temperature and will not have an adverse effect on the final performance of the ceramic substrate.

[0012] In the anti-bending alumina multilayer ceramic substrate of the present invention, the dispersant evenly disperses the particles in the ceramic slurry, improves the stability and fluidity of the slurry, is beneficial to the tape casting process, and ensures the quality uniformity of the blank.

[0013] As a further technical solution, the mass volume ratio of the calcium oxide to the ethanol is 1g:20~22mL.

[0014] As a further technical solution, the mass ratio of magnesium oxide to calcium oxide is 13:7-8;

[0015] The mass ratio of the calcium oxide to the glucose is 8-9:1;

[0016] The mass ratio of the carbon coating material to titanium dioxide is 5-6:1.

[0017] In the anti-bending alumina multilayer 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, or 13:8, preferably 13:8.

[0018] In the anti-bending alumina multilayer ceramic substrate of the present invention, the mass ratio of the carbon coating 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, or 6:1.

[0019] In the present invention's flex-resistant alumina multilayer ceramic substrate, a carbon-coated material to titanium dioxide mass ratio of 5 to 6:1 ensures that the titanium dioxide is evenly distributed on the carbon-coated calcium oxide surface and fully exerts its effect. During the sintering process, the evenly distributed titanium dioxide can more efficiently catalyze the formation of spinel. As an important crystalline phase, the amount and distribution of spinel have a critical impact on the microstructure and performance of the alumina multilayer ceramic substrate. The spinel generated at the appropriate ratio synergizes with the carbon-coated structure to further optimize the grain boundary structure and inter-grain bonding within the ceramic substrate, thereby significantly improving the bending strength of the alumina multilayer ceramic substrate, enabling it to withstand greater external forces in practical applications and reducing the risk of fracture and damage.

[0020] As a further technical solution, the annealing treatment temperature is 450-560°C, the time is 6-7 hours, and the atmosphere is argon;

[0021] The ball milling speed is 500-600 rpm, and the time is 3-5 hours.

[0022] 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 each independently 100-200 nm.

[0023] 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 each independently 100 nm.

[0024] In the anti-bending alumina multilayer ceramic substrate of the present invention, the calcium oxide particle size is in the range of 1 to 10 μm. During the ceramic substrate molding process, the larger particle size makes the calcium oxide relatively uniform and stable in the system, and is less likely to agglomerate. It also ensures the uniformity of the carbon coating structure, enhances the protection of the calcium oxide, and reduces the performance degradation caused by moisture absorption. The particle size of magnesium oxide and titanium dioxide is in the range of 100~200nm, with a large specific surface area, which enables titanium dioxide to better exert its catalytic activity. When compounded with carbon-coated calcium oxide, small-particle magnesium oxide and titanium dioxide can fully and evenly adhere to its surface. During the sintering process, the highly active titanium dioxide effectively catalyzes the formation of magnesium-aluminum spinel. Moreover, the specific particle size combination of magnesium oxide, calcium oxide and titanium dioxide produces a synergistic effect. The stable structure constructed by the larger particle size of calcium oxide provides a good support and dispersion basis for magnesium oxide and titanium dioxide, allowing titanium dioxide to fully exert its catalytic and grain-refining effects. The grain refinement of titanium dioxide and the promotion of magnesium-aluminum spinel generated by magnesium oxide and aluminum oxide further optimize the microstructure and synergistically improve the fracture toughness of the anti-bending alumina multilayer ceramic substrate.

[0025] As a further technical solution, the plasticizer includes one of dibutyl phthalate and dinonyl phthalate.

[0026] As a further technical solution, the binder includes one of polyvinyl butyral and polyvinyl alcohol.

[0027] As a further technical solution, the dispersant includes one of sodium polyacrylate and polyethylene glycol.

[0028] As a further technical solution, the solvent includes one or more of n-butanol, isopropanol, and ethanol.

[0029] The present invention also provides a method for preparing a bending-resistant alumina multilayer ceramic substrate, which comprises the following steps:

[0030] S1. Evenly mix alumina, plasticizer, additive, dispersant, and solvent, and then add a binder to obtain a slurry;

[0031] S2, tape-casting the slurry and drying it to obtain a blank;

[0032] S3, punching the blank, and performing surface printing, lamination, upper and lower conductive bonding, cutting, sintering, and cooling to obtain the anti-bending alumina multilayer ceramic substrate.

[0033] The working principle and beneficial effects of the present invention are:

[0034] In the present invention, an additive is prepared by co-existing magnesium oxide, calcium oxide, glucose and titanium dioxide, and added to an alumina multilayer ceramic substrate, thereby significantly improving the flexural strength of the alumina multilayer ceramic substrate. The reason is that after the surface of the calcium oxide is coated with a carbon layer, direct contact between the calcium oxide and water is avoided, thereby improving the stability of the calcium oxide. In addition, after the carbon layer is coated, the calcium oxide is composited with magnesium oxide and titanium dioxide, and the titanium dioxide on the carbon layer catalyzes the formation of magnesium-aluminum spinel during the sintering process. The two mechanisms work synergistically to greatly improve the flexural strength of the alumina multilayer ceramic substrate. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] In the following examples and comparative examples, the particle size of aluminum oxide is 1 μm, the weight average molecular weight of polyvinyl butyral is 30,000, and the weight average molecular weight of polyethylene glycol is 4,000, and the model is PEG4000.

[0037] Example 1

[0038] The anti-bending alumina multilayer ceramic substrate comprises the following components in parts by weight: 110 parts of alumina, 8 parts of dibutyl phthalate, 12 parts of an additive, 7 parts of polyvinyl butyral, 6 parts of polyethylene glycol, 35 parts of n-butanol, and 35 parts of isopropyl alcohol.

[0039] The preparation method of the auxiliary agent comprises the following steps:

[0040] A1. Add calcium oxide with a particle size of 1 μm to ethanol and 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 the mixture is uniform, and concentrate to obtain a glucose-coated material.

[0041] A2. Annealing the glucose-coated material (560° C. for 6 h in an argon atmosphere) to obtain a carbon-coated material;

[0042] A3. The carbon-coated material was mixed with magnesium oxide (100 nm in particle size) and titanium dioxide (1 μm in particle size) (the mass ratio of magnesium oxide to calcium oxide was 13:8, and the mass ratio of carbon-coated material to titanium dioxide was 8:1). The mixture was then ball-milled at 600 rpm for 3 h to obtain an additive.

[0043] A method for preparing a bending-resistant alumina multilayer ceramic substrate comprises the following steps:

[0044] S1. Evenly mix alumina, dibutyl phthalate, additives, polyethylene glycol, n-butanol, and isopropyl alcohol, and then add polyvinyl butyral to obtain a slurry;

[0045] S2, tape-casting the slurry and drying it to obtain a blank;

[0046] S3, punching the blank, performing surface printing, lamination, upper and lower conductive, cutting, sintering at 1700° C. for 5 hours, and cooling to obtain a bending-resistant alumina multilayer ceramic substrate;

[0047] The raw material for surface printing is tungsten paste, and the printing thickness is 15μm;

[0048] The number of layers of the multilayer ceramic substrate is 30.

[0049] Example 2

[0050] The anti-bending alumina multilayer ceramic substrate comprises 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;

[0051] The preparation method of the auxiliary agent comprises the following steps:

[0052] A1. Add calcium oxide with a particle size of 10 μm to ethanol and 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 the mixture is uniform, and concentrate to obtain a glucose-coated material.

[0053] A2. Annealing the glucose-coated material (at 450° C. for 7 h in an argon atmosphere) to obtain a carbon-coated material;

[0054] A3. The carbon-coated material was mixed with magnesium oxide with a particle size of 100 nm and titanium dioxide with a particle size of 1 μm (the mass ratio of magnesium oxide to calcium oxide was 13:7, and the mass ratio of carbon-coated material to titanium dioxide was 4:1), and then ball-milled at 500 rpm for 5 h to obtain an additive;

[0055] A method for preparing a bending-resistant alumina multilayer ceramic substrate comprises the following steps:

[0056] S1. Mixing aluminum oxide, dinonyl phthalate, additives, polyethylene glycol, and ethanol, and then adding polyvinyl butyral to obtain a slurry;

[0057] S2, tape-casting the slurry and drying it to obtain a blank;

[0058] S3, punching the blank, performing surface printing, lamination, upper and lower conductive, cutting, sintering at 1700° C. for 5 hours, and cooling to obtain a bending-resistant alumina multilayer ceramic substrate;

[0059] The raw material for surface printing is tungsten paste, and the printing thickness is 15μm;

[0060] The number of layers of the multilayer ceramic substrate is 30.

[0061] Example 3

[0062] The only difference between this embodiment and embodiment 2 is that the mass ratio of the carbon coating material to the titanium dioxide with a particle size of 1 μm in this embodiment is 7:1.

[0063] Example 4

[0064] The only difference between this embodiment and embodiment 2 is that the mass ratio of the carbon coating material to the titanium dioxide with a particle size of 1 μm in this embodiment is 5:1.

[0065] Example 5

[0066] The only difference between this embodiment and embodiment 2 is that the mass ratio of the carbon coating material to the titanium dioxide with a particle size of 1 μm in this embodiment is 6:1.

[0067] Example 6

[0068] The only difference between this embodiment and embodiment 5 is that the particle size of titanium dioxide in this embodiment is 50 nm.

[0069] Example 7

[0070] The only difference between this embodiment and embodiment 5 is that the particle size of titanium dioxide in this embodiment is 100 nm.

[0071] Example 8

[0072] The only difference between this embodiment and embodiment 5 is that the particle size of titanium dioxide in this embodiment is 200 nm.

[0073] Comparative Example 1

[0074] The only difference between this comparative example and Example 2 is that the preparation method of the auxiliary agent in this comparative example includes the following steps:

[0075] A1. Add calcium oxide with a particle size of 10 μm to ethanol and 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 the mixture is uniform, and concentrate to obtain a glucose-coated material.

[0076] A2. Annealing the glucose-coated material (at 450° C. for 7 h in an argon atmosphere) to obtain a carbon-coated material;

[0077] A3. The carbon-coated material was mixed evenly with magnesium oxide with a particle size of 100 nm (the mass ratio of magnesium oxide to calcium oxide was 13:7), and ball-milled at a speed of 500 rpm for 5 h to obtain an additive.

[0078] Comparative Example 2

[0079] The only difference between this comparative example and Example 2 is that the preparation method of the auxiliary agent in this comparative example includes the following steps:

[0080] 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 uniformly mixed in a mass ratio of 13:7:1.75, and then ball-milled at a rotation speed of 500 rpm for 5 hours to obtain an additive.

[0081] Comparative Example 3

[0082] The only difference between this comparative example and Example 2 is that the auxiliary agent 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.

[0083] Experimental Example 1

[0084] The bending strength of the resistant alumina multilayer ceramic substrates prepared in Examples 1-5 and Comparative Examples 1-3 was tested using the three-point bending method specified in GB / T 6569-2006, "Test Method for Bending Strength of Fine Ceramics." The test results are shown in Table 1.

[0085] Table 1 Bending strength test results

[0086]

[0087] As shown in Table 1, the bending strength of the bending-resistant alumina multilayer ceramic substrates prepared in Examples 1 to 5 of the present invention reaches above 427 MPa. Therefore, in the present invention, calcium oxide is carbon-coated and then composited with magnesium oxide and titanium dioxide to improve the bending strength of the alumina multilayer ceramic substrate.

[0088] Experimental Example 2

[0089] The bending-resistant alumina multilayer ceramic substrates prepared in Examples 5-8 were tested for fracture toughness using the three-point bending method specified in GB / T 23806-2009, "Fine Ceramics Fracture Toughness Test Method: Single Edge Precracked Beam (SEPB) Method." The test results are shown in Table 2.

[0090] Table 2 Fracture toughness test results

[0091]

[0092] As shown in Table 2, the fracture toughness of the bending-resistant alumina multilayer ceramic substrates prepared in Examples 7 and 8 of the present invention reached 5.02 MPa / m 2 Therefore, the present invention selects magnesium oxide and calcium oxide with a particle size of 1 to 10 μm and titanium dioxide with a particle size of 100 to 200 nm to compound, thereby improving the fracture toughness of the anti-bending alumina multilayer ceramic substrate.

[0093] The above are only 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 should be included in the scope of protection of the present invention.

Claims

1. Anti-bending alumina multilayer ceramic substrate, characterized in that, The raw materials include the following components in parts by weight: 95-110 parts of aluminum oxide, 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 comprises the following steps: A1. Add calcium oxide to ethanol, add glucose, stir until the mixture is uniform, and concentrate to obtain a glucose-coated material; A2, annealing the glucose-coated material to obtain a carbon-coated material; A3, mixing the carbon-coated material with magnesium oxide and titanium dioxide and then ball-milling to obtain the additive; 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 coating material to titanium dioxide is 5-6:1; The particle size of the calcium oxide is 1-10 μm, and the particle sizes of the magnesium oxide and titanium dioxide are each independently 100-200 nm.

2. The bending-resistant alumina multilayer ceramic substrate according to claim 1, characterized in that: The annealing treatment temperature is 450-560°C, the time is 6-7 hours, and the atmosphere is argon; The ball milling speed is 500-600 rpm, and the time is 3-5 hours.

3. The bending-resistant alumina multilayer ceramic substrate according to claim 1, characterized in that: The particle size of the calcium oxide is 10 μm, and the particle sizes of the magnesium oxide and titanium dioxide are each independently 100 nm.

4. The bending-resistant alumina multilayer ceramic substrate according to claim 1, characterized in that: The plasticizer includes one of dibutyl phthalate and dinonyl phthalate.

5. The bending-resistant alumina multilayer ceramic substrate according to claim 1, characterized in that: The binder includes one of polyvinyl butyral and polyvinyl alcohol.

6. The bending-resistant alumina multilayer ceramic substrate according to claim 1, characterized in that: The dispersant includes one of sodium polyacrylate and polyethylene glycol.

7. The bending-resistant alumina multilayer ceramic substrate according to claim 1, characterized in that: The solvent includes one or more of n-butanol, isopropanol, and ethanol.

8. A method for preparing a bending-resistant alumina multilayer ceramic substrate, for preparing the bending-resistant alumina multilayer ceramic substrate according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Evenly mix alumina, plasticizer, additive, dispersant, and solvent, and then add a binder to obtain a slurry; S2, tape-casting the slurry and drying it to obtain a blank; S3, punching the blank, and performing surface printing, lamination, upper and lower conductive bonding, cutting, sintering, and cooling to obtain the anti-bending alumina multilayer ceramic substrate.

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