Alumina multilayer ceramic substrate and preparation method thereof

Abstract

The invention relates to the technical field of ceramic substrates, and provides an aluminum oxide multilayer ceramic substrate and a preparation method thereof. The aluminum oxide multilayer ceramic substrate comprises the following raw materials in parts by weight: 80-90 parts of pretreated aluminum oxide, 1-4 parts of a sintering aid, 1-2 parts of a dispersing agent, 6-12 parts of a binder and 85-95 parts of a solvent, the preparation method of the pretreated aluminum oxide comprises the following steps: performing wet ball milling, drying, sintering and crushing on aluminum oxide, manganese sesquioxide, magnesium oxide and zirconium oxide to obtain the pretreated aluminum oxide. According to the technical scheme, the problem that the bending strength of the aluminum oxide multilayer ceramic substrate prepared from the aluminum oxide raw material with the purity of 95% in the related technology is low is solved.

Description

Technical Field

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

[0002] Alumina ceramic substrates are usually classified according to the purity of the alumina in the raw materials. Alumina ceramic substrates can be divided into 99 porcelain, 95 porcelain, 90 porcelain, 85 porcelain and other varieties. Generally speaking, ceramic substrates made of 99% pure alumina have superior performance in density, mechanical properties, etc., but the high cost limits its large-scale application. In contrast, alumina multilayer ceramic substrates with a purity of 95% are expected to have a better balance between cost and performance. However, since the 95% pure alumina raw materials inevitably contain impurities such as ferric oxide, these impurities will affect the growth of alumina crystals and the bonding between grains during the preparation of ceramic substrates, resulting in more microscopic defects in the prepared alumina multilayer ceramic substrates, which makes it difficult for its bending strength to meet the growing demand for high-end electronic packaging.

[0003] Therefore, when an alumina multilayer ceramic substrate is prepared using 95% pure alumina raw material, the problem of poor bending strength of the alumina multilayer ceramic substrate needs to be solved urgently. Summary of the invention

[0004] The present invention provides an alumina multilayer ceramic substrate and a preparation method thereof, which solves the problem of low bending strength of the alumina multilayer ceramic substrate prepared by using 95% pure alumina raw materials in the related art.

[0005] The technical solution of the present invention is as follows: The present invention provides an alumina multilayer ceramic substrate, which comprises the following raw materials in parts by weight: 80-90 parts of pretreated alumina, 1-4 parts of a sintering aid, 1-2 parts of a dispersant, 6-12 parts of a binder, and 85-95 parts of a solvent; The preparation method of the pretreated alumina comprises the following steps: Alumina, manganese trioxide, magnesium oxide and zirconium oxide are wet ball-milled, dried, sintered and crushed to obtain pretreated alumina.

[0006] As a further technical solution, the solvent is water.

[0007] As a further technical solution, the mass ratio of the aluminum oxide, manganese trioxide and magnesium oxide is 100:1:2~3.

[0008] As a further technical solution, the mass ratio of aluminum oxide to zirconium oxide is 150:0.5~1.5.

[0009] As a further technical solution, the rotation speed during the wet ball milling is 800-1000 rpm, for example, it can be 800 rpm, 850 rpm, 900 rpm, 950 rpm, or 1000 rpm.

[0010] As a further technical solution, the wet ball milling time is 3 to 5 hours, for example, 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours.

[0011] As a further technical solution, the rotation speed during the wet ball milling is 900 rpm and the time is 4 hours.

[0012] The sintering temperature is 1000-1200° C. and the sintering time is 2-3 hours.

[0013] As a further technical solution, during the wet ball milling, the solvent is anhydrous ethanol.

[0014] As a further technical solution, the mass ratio of the anhydrous ethanol to the aluminum oxide is 1-2:1.

[0015] As a further technical solution, the particle size of the pretreated alumina is 10-15 μm, for example, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, or 15 μm.

[0016] As a further technical solution, the sintering aid includes CeO 2 , Y 2 O 3 , CaO, La 2 O 3 One or more of; wherein the sintering aid can be CeO 2 , Y 2 O 3 and CaO, can be Y 2 O 3 and CaO; preferably, the sintering aid is CeO in a mass ratio of 1:1:2 2 , Y 2 O 3 and CaO.

[0017] The present invention uses CeO 2 , Y 2 O 3 and CaO as sintering aids for alumina multilayer ceramic substrates, CeO 2 Can reduce surface energy and inhibit abnormal grain growth, Y 2 O 3 It forms a solid solution with alumina, reduces the sintering temperature and enhances the grain boundary bonding force, improves the density of ceramics, and CaO can promote particle rearrangement and material transfer, accelerating sintering. CeO 2 , Y2 O 3 And CaO as the sintering aid of the alumina multilayer ceramic substrate can ensure the strength and processability of the alumina multilayer ceramic substrate.

[0018] The dispersant includes one or both of sodium polyacrylate and potassium polyacrylate, preferably sodium polyacrylate; The binder includes one or more of carboxymethyl cellulose, polyvinyl alcohol, and polyvinyl butyral, preferably polyvinyl alcohol.

[0019] As a further technical solution, the preparation method of the pretreated alumina comprises the following steps: A1. Wet-milling, drying, sintering and crushing aluminum oxide, manganese oxide, magnesium oxide and zirconium oxide to obtain a pretreated product; A2. Mix the pretreated product and 2-acetoxybenzoic acid solution, and dry them to obtain the pretreated alumina.

[0020] In the present invention, before preparing the alumina multilayer ceramic substrate, alumina, manganese trioxide, magnesium oxide and zirconium oxide are firstly wet ball milled, and after sintering treatment, 2-acetoxybenzoic acid is further used to composite pre-treat the alumina, thereby effectively improving the fracture toughness of the alumina multilayer ceramic substrate. Since 2-acetoxybenzoic acid contains a carboxyl group, it can be closely adsorbed on the surface of the pre-treated material particles, increase the electrostatic repulsion between the particles, and improve the dispersibility of the pre-treated material. At the same time, the acetoxy part has an affinity for organophilicity, and can build a bridge between the pre-treated material particles and organic molecules such as a binder, improve the compatibility of the two, and finally obtain a uniform and dense ceramic substrate, which can better resist cracks, thereby improving the fracture toughness of the alumina multilayer ceramic substrate.

[0021] As a further technical solution, the mass ratio of the pretreated material to the 2-acetoxybenzoic acid solution is 1:3~5.

[0022] As a further technical solution, in the 2-acetoxybenzoic acid solution, the mass ratio of 2-acetoxybenzoic acid to ethanol is 1:10-12.

[0023] The present invention also provides a method for preparing an alumina multilayer ceramic substrate, which is used to prepare the alumina multilayer ceramic substrate, comprising the following steps: S1, mixing pretreated alumina, a sintering aid, a dispersant and a solvent to obtain a mixture; S2, adding a binder to the mixture, mixing, tape casting, and drying to obtain a green porcelain sheet; S3, after punching the raw ceramic sheet, surface printing, lamination, upper and lower conduction, cutting, sintering, and cooling are performed to obtain the alumina multilayer ceramic substrate.

[0024] The working principle and beneficial effects of the present invention are: In the present invention, alumina, manganese trioxide, magnesium oxide, and zirconium oxide are wet ball-milled, and pretreated alumina is obtained after sintering. The use of pretreated alumina significantly improves the bending strength of the alumina multilayer ceramic substrate. In the prior art, alumina and other metal compounds are generally used directly as raw materials for ceramic substrates. The present invention uses alumina pretreated with manganese trioxide, magnesium oxide, and zirconium oxide as the raw material for the ceramic substrate, which improves the bending strength of the alumina multilayer ceramic substrate from two aspects: impurity binding and lowering the sintering temperature: during the wet ball milling process, alumina, manganese trioxide, magnesium oxide, and zirconium oxide are fully mixed, the raw material particles are refined, and the contact area between the substances is increased. During the sintering process, impurities in manganese trioxide, magnesium oxide, and alumina form a spinel phase. At the same time, the pretreated alumina After being mixed with other raw materials to obtain a ceramic substrate, it can also become a reinforcing skeleton inside the ceramic; among them, zirconium oxide, due to its special crystal structure, will undergo phase change during the sintering process, absorb energy, and reduce the sintering temperature at the same time, which is conducive to the uniform distribution of the spinel phase formed by impurities in manganese trioxide, magnesium oxide and aluminum oxide. Therefore, the present invention wet-mills aluminum oxide, manganese trioxide, magnesium oxide and zirconium oxide, and obtains pretreated alumina after sintering. The pretreated alumina absorbs energy when the ceramic is subjected to force to prevent crack propagation, thereby significantly improving the bending strength of the alumina multilayer ceramic substrate. DETAILED DESCRIPTION

[0025] 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0026] In the following examples and comparative examples, the purity of aluminum oxide is 95%, the particle size is 20 μm, the particle size of manganese trioxide is 100 nm, the particle size of magnesium oxide is 10 μm, the particle size of zirconium oxide is 10 μm, the weight average molecular weight of polyvinyl alcohol is 10,000, and the particle size of CeO is 100 μm. 2 The particle size is 100nm, Y 2 O 3 The particle size is 100nm, and the CaO particle size is 100nm.

[0027] Example 1 Alumina multilayer ceramic substrate, comprising the following raw materials in parts by weight: 80 parts of pretreated alumina, 1 part of sintering aid, 1 part of sodium polyacrylate, 6 parts of polyvinyl alcohol, and 85 parts of water; the sintering aid is CeO 2 , Y 2 O3 and CaO; The preparation method of pretreated alumina comprises the following steps: Alumina, manganese trioxide, magnesium oxide and zirconium oxide were wet ball milled at a rotation speed of 800 rpm (the solvent was anhydrous ethanol, and the mass ratio of anhydrous ethanol to alumina was 2:1) for 5 hours, dried, sintered at 1000°C for 3 hours, and crushed to obtain pretreated alumina with a particle size of 10 μm; wherein the mass ratio of alumina, manganese trioxide and magnesium oxide was 100:1:0.5, and the mass ratio of alumina to zirconium oxide was 150:1.5; The method for preparing an alumina multilayer ceramic substrate comprises the following steps: S1, mixing pretreated alumina, a sintering aid, sodium polyacrylate and water to obtain a mixture; S2, adding polyvinyl alcohol to the mixture to mix, casting, and drying to obtain a green porcelain sheet; S3. After punching holes in the raw ceramic sheet, the raw ceramic sheet is subjected to surface printing, lamination (30 layers), upper and lower conduction, cutting, sintering, and cooling to obtain an alumina multilayer ceramic substrate.

[0028] Example 2 Alumina multilayer ceramic substrate, comprising the following raw materials in parts by weight: 90 parts of pretreated alumina, 4 parts of sintering aid, 2 parts of sodium polyacrylate, 12 parts of polyvinyl alcohol, and 95 parts of water; the sintering aid is Y 2 O 3 and CaO; The preparation method of pretreated alumina comprises the following steps: Alumina, manganese trioxide, magnesium oxide and zirconium oxide were wet ball milled at a rotation speed of 1000 rpm (the solvent was anhydrous ethanol, and the mass ratio of anhydrous ethanol to alumina was 1:1) for 3 hours, dried, sintered at 1200°C for 2 hours, and crushed to obtain pretreated alumina with a particle size of 15 μm; wherein the mass ratio of alumina, manganese trioxide and magnesium oxide was 100:1:0.5, and the mass ratio of alumina to zirconium oxide was 150:1; The method for preparing an alumina multilayer ceramic substrate comprises the following steps: S1, mixing pretreated alumina, a sintering aid, sodium polyacrylate and water to obtain a mixture; S2, adding polyvinyl alcohol to the mixture to mix, casting, and drying to obtain a green porcelain sheet; S3. After punching holes in the raw ceramic sheet, the raw ceramic sheet is subjected to surface printing, lamination (30 layers), upper and lower conduction, cutting, sintering, and cooling to obtain an alumina multilayer ceramic substrate.

[0029] Example 3 Alumina multilayer ceramic substrate, comprising the following raw materials in parts by weight: 85 parts of pretreated alumina, 2 parts of sintering aid, 1.5 parts of sodium polyacrylate, 8 parts of polyvinyl alcohol, and 90 parts of water; the sintering aid is CeO 2 , Y 2 O 3 and CaO; The preparation method of pretreated alumina comprises the following steps: Alumina, manganese trioxide, magnesium oxide and zirconium oxide were wet ball milled at a rotation speed of 900 rpm (the solvent was anhydrous ethanol, and the mass ratio of anhydrous ethanol to alumina was 1:1) for 4 hours, dried, sintered at 1100°C for 2.5 hours, and crushed to obtain pretreated alumina with a particle size of 10 μm; wherein the mass ratio of alumina, manganese trioxide and magnesium oxide was 100:1:0.5, and the mass ratio of alumina to zirconium oxide was 150:0.5; The method for preparing an alumina multilayer ceramic substrate comprises the following steps: S1, mixing pretreated alumina, a sintering aid, sodium polyacrylate and water to obtain a mixture; S2, adding polyvinyl alcohol to the mixture to mix, casting, and drying to obtain a green porcelain sheet; S3. After punching holes in the raw ceramic sheet, the raw ceramic sheet is subjected to surface printing, lamination (30 layers), upper and lower conduction, cutting, sintering, and cooling to obtain an alumina multilayer ceramic substrate.

[0030] Example 4 The only difference between this embodiment and embodiment 3 is that the mass ratio of aluminum oxide, manganese trioxide and magnesium oxide is 100:1:4.

[0031] Example 5 The only difference between this embodiment and embodiment 3 is that the mass ratio of aluminum oxide, manganese trioxide and magnesium oxide is 100:1:2.

[0032] Example 6 The only difference between this embodiment and embodiment 3 is that the mass ratio of aluminum oxide, manganese trioxide and magnesium oxide is 100:1:3.

[0033] Example 7 The only difference between this embodiment and embodiment 6 is that the preparation method of pretreated alumina comprises the following steps: A1. Wet ball milling of aluminum oxide, manganese trioxide, magnesium oxide and zirconium oxide at a rotation speed of 900 rpm (the solvent is anhydrous ethanol, and the mass ratio of anhydrous ethanol to aluminum oxide is 1:1) for 4 hours, drying, sintering at 1100°C for 2.5 hours, and crushing to obtain a pretreated product with a particle size of 10 μm; wherein the mass ratio of aluminum oxide, manganese trioxide and magnesium oxide is 100:1:3, and the mass ratio of aluminum oxide to zirconium oxide is 150:0.5; A2. 2-acetoxybenzoic acid and ethanol are mixed in a mass ratio of 1:10 to obtain a 2-acetoxybenzoic acid solution, and the pretreated product and the 2-acetoxybenzoic acid solution are mixed in a mass ratio of 1:5, and dried to obtain pretreated alumina.

[0034] Example 8 The only difference between this embodiment and embodiment 6 is that the preparation method of pretreated alumina comprises the following steps: A1. Wet ball milling of aluminum oxide, manganese trioxide, magnesium oxide and zirconium oxide at a rotation speed of 900 rpm (the solvent is anhydrous ethanol, and the mass ratio of anhydrous ethanol to aluminum oxide is 1:1) for 4 hours, drying, sintering at 1100°C for 2.5 hours, and crushing to obtain a pretreated product with a particle size of 10 μm; wherein the mass ratio of aluminum oxide, manganese trioxide and magnesium oxide is 100:1:3, and the mass ratio of aluminum oxide to zirconium oxide is 150:0.5; A2. 2-acetoxybenzoic acid and ethanol are mixed in a mass ratio of 1:12 to obtain a 2-acetoxybenzoic acid solution, and the pretreated product and the 2-acetoxybenzoic acid solution are mixed in a mass ratio of 1:3, and dried to obtain pretreated alumina.

[0035] Comparative Example 1 The only difference between this embodiment and embodiment 3 is that the preparation method of pretreated alumina comprises the following steps: Alumina, magnesium oxide and zirconium oxide were wet ball milled at a rotation speed of 900 rpm (the solvent was anhydrous ethanol, and the mass ratio of anhydrous ethanol to alumina was 1:1) for 4 hours, dried, sintered at 1100°C for 2.5 hours, and crushed to obtain pretreated alumina with a particle size of 10 μm; wherein the mass ratio of aluminum oxide to magnesium oxide was 100:0.5, and the mass ratio of aluminum oxide to zirconium oxide was 150:0.5.

[0036] Comparative Example 2 The only difference between this embodiment and embodiment 3 is that the preparation method of pretreated alumina comprises the following steps: Alumina, manganese trioxide and zirconium oxide were wet ball milled at a rotation speed of 900 rpm (the solvent was anhydrous ethanol, and the mass ratio of anhydrous ethanol to alumina was 1:1) for 4 hours, dried, sintered at 1100°C for 2.5 hours, and crushed to obtain pretreated alumina with a particle size of 10 μm; wherein the mass ratio of alumina to manganese trioxide was 100:1, and the mass ratio of alumina to zirconium oxide was 150:0.5.

[0037] Comparative Example 3 The only difference between this embodiment and embodiment 3 is that the preparation method of pretreated alumina comprises the following steps: Alumina, manganese trioxide and magnesium oxide were wet ball milled at a rotation speed of 900 rpm (the solvent was anhydrous ethanol, and the mass ratio of anhydrous ethanol to alumina was 1:1) for 4 hours, dried, sintered at 1100°C for 2.5 hours, and crushed to obtain pretreated alumina with a particle size of 10 μm; wherein the mass ratio of alumina, manganese trioxide and magnesium oxide was 100:1:0.5.

[0038] Comparative Example 4 Alumina multilayer ceramic substrate, comprising the following raw materials in parts by weight: 85 parts of pretreated alumina, 2 parts of sintering aid, 1.5 parts of sodium polyacrylate, 8 parts of polyvinyl alcohol, and 90 parts of water; the sintering aid is CeO 2 , Y 2 O 3 and CaO; The preparation method of pretreated alumina comprises the following steps: Alumina, manganese trioxide, magnesium oxide and zirconium oxide were wet ball milled at a rotation speed of 900 rpm (the solvent was anhydrous ethanol, and the mass ratio of anhydrous ethanol to alumina was 1:1) for 4 hours, and dried to obtain pretreated alumina; wherein the mass ratio of alumina, manganese trioxide and magnesium oxide was 100:1:0.5, and the mass ratio of alumina to zirconium oxide was 150:0.5; The method for preparing an alumina multilayer ceramic substrate comprises the following steps: S1, mixing pretreated alumina, a sintering aid, sodium polyacrylate and water to obtain a mixture; S2, adding polyvinyl alcohol to the mixture to mix, casting, and drying to obtain a green porcelain sheet; S3. After punching holes in the raw ceramic sheet, the raw ceramic sheet is subjected to surface printing, lamination (30 layers), upper and lower conduction, cutting, sintering, and cooling to obtain an alumina multilayer ceramic substrate.

[0039] Experimental Example 1 According to the test method specified in GB / T 6569-2006 "Bending Strength Test Method for Fine Ceramics", the alumina multilayer ceramic substrates prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were tested for bending strength. The test method adopted three-point bending. The results are shown in Table 1.

[0040] Table 1 Performance test results

[0041] Compared with Comparative Examples 1 to 4, the bending strength of the alumina multilayer ceramic substrates obtained in Examples 1 to 6 is higher, indicating that the alumina, manganese trioxide, magnesium oxide, and zirconium oxide are wet-ball milled, and pretreated alumina is obtained after sintering. The pretreated alumina is used as the raw material of the alumina multilayer ceramic substrate, which significantly improves the bending strength of the alumina multilayer ceramic substrate.

[0042] Experimental Example 2 According to the sample requirements and test methods of GB / T 23806-2009 "Fine Ceramics Fracture Toughness Test Method Single Edge Precracked Beam (SEPB) Method", the fracture toughness tests were performed on the alumina multilayer ceramic substrates prepared in Examples 6 to 8, respectively. The test results are shown in Table 2.

[0043] Table 2 Performance test results

[0044] Compared with Example 6, the fracture toughness of the alumina multilayer ceramic substrates obtained in Examples 7-8 is higher, indicating that further treatment of the pretreated material with 2-acetoxybenzoic acid improves the fracture toughness of the alumina multilayer ceramic substrate.

[0045] The above are only 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 in the protection scope of the present invention.

Claims

1. Alumina multilayer ceramic substrate, characterized in that: The raw materials include the following parts by weight: 80-90 parts of pretreated alumina, 1-4 parts of sintering aid, 1-2 parts of dispersant, 6-12 parts of binder, and 85-95 parts of solvent; The preparation method of the pretreated alumina comprises the following steps: Alumina, manganese trioxide, magnesium oxide and zirconium oxide are wet ball-milled, dried, sintered and crushed to obtain pretreated alumina.

2. The alumina multilayer ceramic substrate according to claim 1, characterized in that: The mass ratio of the aluminum oxide, manganese trioxide and magnesium oxide is 100:1:2-3.

3. The alumina multilayer ceramic substrate according to claim 2, characterized in that: The mass ratio of the aluminum oxide to the zirconium oxide is 150:0.5-1.

5.

4. The alumina multilayer ceramic substrate according to claim 1, characterized in that: The wet ball milling process is performed at a speed of 800-1000 rpm for 3-5 hours. The sintering temperature is 1000-1200° C. and the sintering time is 2-3 hours.

5. The alumina multilayer ceramic substrate according to claim 1, characterized in that: The particle size of the pretreated alumina is 10-15 μm.

6. The alumina multilayer ceramic substrate according to claim 1, characterized in that: The sintering aid includes one or more of CeO2, Y2O3, CaO, and La2O3; The dispersant includes one or both of triethyl phosphate and tributyl phosphate; The binder includes one or more of carboxymethyl cellulose, polyvinyl alcohol, and polyvinyl butyral.

7. The alumina multilayer ceramic substrate according to claim 1, characterized in that: The preparation method of the pretreated alumina comprises the following steps: A1. Wet-milling, drying, sintering and crushing aluminum oxide, manganese oxide, magnesium oxide and zirconium oxide to obtain a pretreated product; A2. Mix the pretreated product and 2-acetoxybenzoic acid solution, and dry them to obtain the pretreated alumina.

8. The alumina multilayer ceramic substrate according to claim 7, characterized in that: The mass ratio of the pretreated material to the 2-acetoxybenzoic acid solution is 1:3-5.

9. The alumina multilayer ceramic substrate according to claim 7, characterized in that: In the 2-acetoxybenzoic acid solution, the mass ratio of 2-acetoxybenzoic acid to ethanol is 1:10-12.

10. A method for preparing an alumina multilayer ceramic substrate, for preparing the alumina multilayer ceramic substrate according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, mixing pretreated alumina, a sintering aid, a dispersant and a solvent to obtain a mixture; S2, adding a binder to the mixture, mixing, tape casting, and drying to obtain a green porcelain sheet; S3, after punching the raw ceramic sheet, surface printing, lamination, upper and lower conduction, cutting, sintering, and cooling are performed to obtain the alumina multilayer ceramic substrate.

Images