Heat-resistant Multilayer Ceramic Substrate and Its Preparation Method

Abstract

The present invention relates to the field of ceramic substrate technology and proposes a heat-resistant multilayer ceramic substrate and a method for preparing the same. The heat-resistant multilayer ceramic substrate comprises the following raw materials by weight: 75-80 parts alumina, 1-3 parts sintering aid, 82-92 parts solvent, 8-14 parts binder, 0.5-1.5 parts dispersant, and 2-6 parts toughening agent. The toughening agent comprises a core-shell structure composite and a calcium-containing compound. The core layer of the core-shell composite is titanium dioxide, and the shell layer is zirconium oxide. This technical solution addresses the low fracture toughness issue of heat-resistant multilayer ceramic substrates in related technologies.

Description

Technical Field

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

[0002] As a key basic material in high-end fields such as aerospace, automotive electronics, and high-power semiconductor devices, the performance of heat-resistant multilayer ceramic substrates directly affects the stability and service life of the entire electronic system.

[0003] Currently, heat-resistant multilayer ceramic substrates generally suffer from low fracture toughness, primarily due to the presence of numerous micropores, cracks, and other defects within their microstructure. These defects can easily become crack sources when subjected to external forces. Under these forces, cracks rapidly propagate, leading to material fracture and reducing the material's toughness. This makes ceramic substrates highly susceptible to crack propagation and even fracture when subjected to thermal, mechanical, or impact loads, severely reducing the reliability and service life of electronic devices.

[0004] Therefore, it is necessary to obtain a heat-resistant multilayer ceramic substrate with high fracture toughness. Summary of the Invention

[0005] The present invention provides a heat-resistant multilayer ceramic substrate and a preparation method thereof, which solves the problem of low fracture toughness of the heat-resistant multilayer ceramic substrate in the related art.

[0006] The technical solutions of the present invention are as follows:

[0007] The present invention provides a heat-resistant multilayer ceramic substrate, comprising the following raw materials in parts by weight: 75-80 parts of aluminum oxide, 1-3 parts of a sintering aid, 82-92 parts of a solvent, 8-14 parts of a binder, 0.5-1.5 parts of a dispersant, and 2-6 parts of a toughening agent;

[0008] The toughening agent includes a core-shell structure composite and a calcium-containing compound;

[0009] The core layer of the core-shell structure composite is titanium dioxide, and the shell layer is zirconium oxide.

[0010] As a further technical solution, the solvent includes water.

[0011] As a further technical solution, the mass ratio of the core-shell structure complex to the calcium-containing compound is 2:3~6.

[0012] In the raw materials of the heat-resistant multilayer ceramic substrate of the present invention, when the mass ratio of the core-shell structure composite and the calcium-containing compound is 2:3-6, the core-shell structure composite has the effect of inhibiting the formation of intracrystalline pores and phase transformation toughening, and the effect of the calcium-containing compound on enhancing the grain boundary bonding force promotes each other and reaches an optimal state, more effectively preventing cracks from extending inside the ceramic substrate, and further improving the fracture toughness of the heat-resistant multilayer ceramic substrate.

[0013] As a further technical solution, the method for preparing the core-shell structure complex comprises the following steps:

[0014] Titanium dioxide and water are ultrasonically mixed, a zirconium oxide precursor is added and the mixture is continuously mixed, a precipitant is added and the mixture is kept warm at 85-95° C. for 2.5-3.5 hours, a solid is collected by centrifugation, dried, and calcined to obtain a core-shell structure composite.

[0015] As a further technical solution, the frequency of the ultrasonic mixing is 40-60 kHz and the time is 15-20 min;

[0016] The calcination temperature is 900-950° C. and the calcination time is 3-4 hours.

[0017] As a further technical solution, the particle size of the titanium dioxide is 100-150 nm, for example, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, or 150 nm.

[0018] As a further technical solution, the precipitant includes one of urea and ammonia;

[0019] The zirconium oxide precursor includes one or both of zirconium nitrate and zirconium sulfate.

[0020] As a further technical solution, the sintering aid includes one or more of Y2O3, B2O3, and La2O3; the sintering aid can be, for example, Y2O3 and La2O3, B2O3 and La2O3, or Y2O3, B2O3 and La2O3. Preferably, the sintering aid is Y2O3, B2O3 and La2O3, wherein the mass ratio of Y2O3, B2O3 and La2O3 is 1:1:1.

[0021] As a further technical solution, the dispersant includes a polyacrylate dispersant.

[0022] Among the raw materials of the heat-resistant multilayer ceramic substrate of the present invention, the dispersant includes a polyacrylate dispersant, and the carboxylic acid groups on its molecular chain can disperse the inorganic raw material particles of the heat-resistant multilayer ceramic substrate more evenly and stably in the solvent system through electrostatic repulsion, steric hindrance, etc., wherein the polyacrylate dispersant includes one or both of sodium polyacrylate and potassium polyacrylate.

[0023] As a further technical solution, the binder includes one or more of polyacrylamide, polyvinyl alcohol, and polyethylene oxide.

[0024] As a further technical solution, the mass ratio of the precipitant to the zirconium oxide precursor is 1-1.5:1;

[0025] The mass ratio of the titanium dioxide, water and zirconium oxide precursor is 3:80:0.5-0.8, for example, it can be 3:80:0.5, 3:80:0.6, 3:80:0.7, or 3:80:0.8.

[0026] As a further technical solution, the calcium-containing compound includes one or more of calcium oxide, calcium fluoride, and calcium chloride.

[0027] As a further technical solution, when the calcium-containing compound includes calcium fluoride and calcium oxide, the mass ratio of calcium fluoride to calcium oxide is 1:4-7.

[0028] In the raw materials of the heat-resistant multilayer ceramic substrate of the present invention, when the calcium-containing compound includes calcium fluoride and calcium oxide, the mass ratio of calcium fluoride to calcium oxide can be, for example, 1:4, 1:5, 1:6, or 1:7, preferably 1:4; wherein the calcium-containing compound, when calcium fluoride and calcium oxide are calcium fluoride and calcium oxide, can cooperate with the core-shell structure composite to further improve the flexural strength of the heat-resistant multilayer ceramic substrate.

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

[0030] S1, mixing alumina, a toughening agent, a sintering aid, a dispersant and a solvent to obtain a primary mixture;

[0031] S2, adding a binder to the primary mixture, mixing, tape casting, and drying to obtain a green porcelain sheet;

[0032] S3, after punching the green ceramic sheet, performing surface printing, lamination, upper and lower conductive bonding, cutting, sintering, and cooling to obtain the heat-resistant multi-layer ceramic substrate.

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

[0034] In the present invention, the raw materials of the multilayer ceramic substrate are compounded with a core-shell structure composite in which the core layer is titanium dioxide and the shell layer is zirconium oxide, and a calcium-containing compound, which significantly improves the fracture toughness of the multilayer ceramic substrate. In the prior art, metal compounds are generally added directly, but the addition of metal compounds does not necessarily have a positive effect on the performance of the multilayer ceramic substrate. For example, titanium dioxide directly used as the raw material of the alumina multilayer ceramic substrate will cause lattice defects of intracrystalline pores, which will have an adverse effect on the performance of the multilayer ceramic substrate. In the present invention, a core-shell structure composite in which the core layer is titanium dioxide and the shell layer is zirconium oxide is used, and the zirconium oxide in the core-shell structure composite is The shell layer limits the direct reaction between titanium dioxide and the alumina matrix, inhibits the problem of a large number of lattice defects caused by the valence change of titanium oxide, and effectively improves the density of the ceramic body. At the same time, the core-shell structure composite added to the multilayer ceramic substrate can prevent crack propagation through phase transformation toughening when subjected to external force, thereby improving the fracture toughness. The calcium-containing compound helps to enhance the grain boundary bonding force and increase the resistance to crack propagation. Therefore, the core layer is titanium dioxide, and the shell layer is zirconium oxide. The core-shell structure composite and the calcium-containing compound are synergistically used as the raw materials of the multilayer ceramic substrate, and the fracture toughness of the heat-resistant multilayer ceramic substrate is improved by inhibiting the formation of internal pores and enhancing the grain boundary bonding force. 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 20 μm, the particle size of calcium oxide is 100 nm, the particle size of calcium fluoride is 10 μm, the particle size of calcium chloride is 10 μm, the weight average molecular weight of polyvinyl alcohol is 10,000, the particle size of Y2O3 is 100 nm, the particle size of La2O3 is 5 μm, and the particle size of B2O3 is 5 μm.

[0037] Example 1

[0038] A heat-resistant multilayer ceramic substrate comprises the following raw materials in parts by weight: 75 parts alumina, 1 part Y2O3, 1 part La2O3, 85 parts water, 10 parts polyvinyl alcohol, 1 part sodium polyacrylate, and 4 parts toughening agent; the toughening agent is a core-shell structure composite and calcium oxide; the core layer of the core-shell structure composite is titanium dioxide, and the shell layer is zirconium oxide; the mass ratio of the core-shell structure composite to calcium oxide is 2:4;

[0039] The preparation method of the core-shell structure complex comprises the following steps:

[0040] Titanium dioxide (particle size of 100 nm) and water were ultrasonically mixed at 45 kHz for 20 minutes, zirconium nitrate was added and mixing continued for 25 minutes, urea was added and kept warm at 90°C for 3 hours, the solid was centrifuged and dried, and calcined at 900°C for 4 hours to obtain a core-shell structure composite; wherein the mass ratio of titanium dioxide, water and zirconium nitrate was 3:80:0.6; the mass ratio of urea and zirconium nitrate was 1:1.

[0041] A method for preparing a heat-resistant multilayer ceramic substrate comprises the following steps:

[0042] S1. Mixing alumina, toughening agent, Y2O3, La2O3, sodium polyacrylate and water to obtain a primary mixture;

[0043] S2, adding polyvinyl alcohol to the primary mixture, mixing, casting, and drying to obtain a green porcelain sheet;

[0044] S3. After punching the green ceramic sheet, surface printing, laminating 30 layers, conducting the top and bottom, cutting, sintering at 1600° C. for 3 hours, and cooling to obtain a heat-resistant multilayer ceramic substrate.

[0045] Example 2

[0046] A heat-resistant multilayer ceramic substrate comprises the following raw materials in parts by weight: 75 parts of aluminum oxide, 0.2 parts of boron 2 O 3 0.8 parts of ladium 2 O 3 82 parts of water, 8 parts of polyvinyl alcohol, 0.5 parts of sodium polyacrylate, and 2 parts of a toughening agent; the toughening agent is a core-shell structure composite and calcium oxide; the core layer of the core-shell structure composite is titanium dioxide, and the shell layer is zirconium oxide; the mass ratio of the core-shell structure composite to calcium oxide is 2:3;

[0047] The preparation method of the core-shell structure complex comprises the following steps:

[0048] Titanium dioxide (particle size of 150 nm) and water were ultrasonically mixed at 40 kHz for 15 minutes, zirconium nitrate was added and mixing was continued for 20 minutes, urea was added and the mixture was kept warm at 85°C for 3.5 hours, the solid was centrifuged and dried, and calcined at 900°C for 4 hours to obtain a core-shell structure composite; wherein the mass ratio of titanium dioxide, water and zirconium nitrate was 3:80:0.5; the mass ratio of urea and zirconium nitrate was 1.5:1.

[0049] A method for preparing a heat-resistant multilayer ceramic substrate comprises the following steps:

[0050] S1, mixing alumina, toughening agent, B2O3, La2O3, sodium polyacrylate and water to obtain a primary mixture;

[0051] S2, adding polyvinyl alcohol to the primary mixture, mixing, casting, and drying to obtain a green porcelain sheet;

[0052] S3. After punching the green ceramic sheet, surface printing, lamination of 30 layers, upper and lower conductive bonding, cutting, sintering at 1500° C. for 4 hours, and cooling to obtain a heat-resistant multilayer ceramic substrate.

[0053] Example 3

[0054] A heat-resistant multilayer ceramic substrate comprises the following raw materials in parts by weight: 80 parts alumina, 1 part Y2O3, 1 part B2O3, 1 part La2O3, 92 parts water, 14 parts polyvinyl alcohol, 1.5 parts sodium polyacrylate, and 6 parts toughening agent; the toughening agent is a core-shell structure composite and calcium oxide; the core layer of the core-shell structure composite is titanium dioxide, and the shell layer is zirconium oxide; the mass ratio of the core-shell structure composite to calcium oxide is 2:2;

[0055] The preparation method of the core-shell structure complex comprises the following steps:

[0056] Titanium dioxide (particle size of 150 nm) and water were ultrasonically mixed at 60 kHz for 15 minutes, zirconium nitrate was added and mixing continued for 30 minutes, urea was added and kept warm at 95°C for 2.5 hours, the solid was centrifuged and dried, and calcined at 950°C for 3 hours to obtain a core-shell structure composite; wherein the mass ratio of titanium dioxide, water and zirconium nitrate was 3:80:0.8; the mass ratio of urea and zirconium nitrate was 1.2:1.

[0057] A method for preparing a heat-resistant multilayer ceramic substrate comprises the following steps:

[0058] S1. Mixing alumina, toughening agent, Y2O3, B2O3, La2O3, sodium polyacrylate and water to obtain a primary mixture;

[0059] S2, adding polyvinyl alcohol to the primary mixture, mixing, casting, and drying to obtain a green porcelain sheet;

[0060] S3. After punching the green ceramic sheet, surface printing, laminating 30 layers, conducting the top and bottom, cutting, sintering at 1650°C for 3 hours, and cooling to obtain a heat-resistant multilayer ceramic substrate.

[0061] Example 4

[0062] The only difference between this embodiment and embodiment 3 is that the mass ratio of the core-shell structure composite to calcium oxide is 2:7.

[0063] Example 5

[0064] The only difference between this embodiment and embodiment 3 is that the mass ratio of the core-shell structure composite to calcium oxide is 2:6.

[0065] Example 6

[0066] The only difference between this embodiment and embodiment 3 is that the mass ratio of the core-shell structure composite to calcium oxide is 2:3.

[0067] Example 7

[0068] The only difference between this embodiment and embodiment 6 is that calcium oxide is replaced by a calcium-containing compound, and the calcium-containing compound is calcium chloride and calcium oxide in a mass ratio of 1:4.

[0069] Example 8

[0070] The only difference between this embodiment and embodiment 6 is that calcium oxide is replaced by a calcium-containing compound, and the calcium-containing compound is calcium fluoride and calcium oxide in a mass ratio of 1:4.

[0071] Example 9

[0072] The only difference between this embodiment and embodiment 6 is that calcium oxide is replaced by a calcium-containing compound, and the calcium-containing compound is calcium fluoride and calcium oxide in a mass ratio of 1:7.

[0073] Comparative Example 1

[0074] The only difference between this comparative example and Example 3 is that the toughening agent is calcium oxide.

[0075] Comparative Example 2

[0076] The only difference between this comparative example and Example 3 is that the toughening agent is a core-shell structure composite.

[0077] Comparative Example 3

[0078] The only difference between this comparative example and Example 3 is that the core-shell structure composite is replaced by titanium dioxide.

[0079] Experimental Example 1

[0080] In accordance with the specimen 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 heat-resistant multilayer ceramic substrates prepared in Examples 1-6 and Comparative Examples 1-3, respectively. The test results are shown in Table 1.

[0081] Table 1 Performance test results

[0082]

[0083] Compared with Comparative Examples 1 to 3, the fracture toughness of the heat-resistant multilayer ceramic substrates prepared in Examples 1 to 6 is higher, indicating that the core-shell structure composite with the core layer being titanium dioxide and the shell layer being zirconium oxide and the calcium-containing compound are synergistically used as the raw materials of the multilayer ceramic substrate, which significantly improves the fracture toughness of the heat-resistant multilayer ceramic substrate.

[0084] Experimental Example 2

[0085] According to the test method specified in GB / T 6569-2006 "Test Method for Bending Strength of Fine Ceramics", the bending strength test was performed on the heat-resistant multilayer ceramic substrates prepared in Examples 6 to 9. The test method adopted three-point bending. The results are shown in Table 2.

[0086] Table 2 Performance test results

[0087]

[0088] Compared with Examples 6 to 7, the bending strength of the heat-resistant multilayer ceramic substrates prepared in Examples 8 to 9 is higher, indicating that the calcium-containing compounds are calcium fluoride and calcium oxide, which, when used in conjunction with the core-shell structure composite as raw materials for the multilayer ceramic substrate, improve the bending strength of the heat-resistant multilayer ceramic substrate.

[0089] Experimental Example 3

[0090] The average linear expansion coefficient of the heat-resistant multilayer ceramic substrates prepared in Examples 1 to 3 was tested in accordance with the standard GB / T 5594.3-2015 "Test methods for properties of structural ceramic materials for electronic components Part 3: Test method for average linear expansion coefficient". The test was performed at a heating rate of 5°C / min and a temperature range of 30°C to 200°C. The results are shown in Table 3.

[0091] Table 3 Performance test results

[0092]

[0093] As shown in Table 3, the average linear expansion coefficient of the multilayer ceramic substrates prepared in Examples 1 to 3 of the present invention is between 6.0×10 -6 ·K -1 ~6.5×10 -6 ·K -1 range, has excellent heat resistance.

[0094] 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. A heat-resistant multilayer ceramic substrate, characterized in that: The method comprises the following raw materials in parts by weight: 75-80 parts of alumina, 1-3 parts of sintering aid, 82-92 parts of solvent, 8-14 parts of binder, 0.5-1.5 parts of dispersant, and 2-6 parts of toughening agent; The toughening agent includes a core-shell structure composite and a calcium-containing compound; The core layer of the core-shell structure composite is titanium dioxide, and the shell layer is zirconium oxide.

2. The heat-resistant multilayer ceramic substrate according to claim 1, wherein The mass ratio of the core-shell structure complex to the calcium-containing compound is 2:3-6.

3. The heat-resistant multilayer ceramic substrate according to claim 1, wherein The preparation method of the core-shell structure complex comprises the following steps: Titanium dioxide and water are ultrasonically mixed, a zirconium oxide precursor is added and the mixture is continuously mixed, a precipitant is added and the mixture is kept warm at 85-95° C. for 2.5-3.5 hours, a solid is collected by centrifugation, dried, and calcined to obtain a core-shell structure composite.

4. The heat-resistant multilayer ceramic substrate according to claim 3, characterized in that The frequency of the ultrasonic mixing is 40-60 kHz and the time is 15-20 minutes; The calcination temperature is 900-950° C. and the calcination time is 3-4 hours.

5. The heat-resistant multilayer ceramic substrate according to claim 3, wherein: The particle size of the titanium dioxide is 100-150 nm.

6. The heat-resistant multilayer ceramic substrate according to claim 3, characterized in that The precipitant includes one of urea and ammonia; The zirconium oxide precursor includes one or both of zirconium nitrate and zirconium sulfate; The sintering aid includes one or more of Y2O3, B2O3, and La2O3; The dispersant includes a polyacrylate dispersant; The binder includes one or more of polyacrylamide, polyvinyl alcohol, and polyethylene oxide.

7. The heat-resistant multilayer ceramic substrate according to claim 3, characterized in that: The mass ratio of the precipitant to the zirconium oxide precursor is 1-1.5:1; The mass ratio of the titanium dioxide, water and zirconium oxide precursor is 3:80:0.5-0.

8.

8. The heat-resistant multilayer ceramic substrate according to claim 1, wherein The calcium-containing compound includes one or more of calcium oxide, calcium fluoride and calcium chloride.

9. The heat-resistant multilayer ceramic substrate according to claim 8, characterized in that: When the calcium-containing compound includes calcium fluoride and calcium oxide, the mass ratio of calcium fluoride to calcium oxide is 1:4-7.

10. A method for preparing a heat-resistant multilayer ceramic substrate, for preparing the heat-resistant multilayer ceramic substrate according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, mixing alumina, a toughening agent, a sintering aid, a dispersant and a solvent to obtain a primary mixture; S2, adding a binder to the primary mixture, mixing, tape casting, and drying to obtain a green porcelain sheet; S3, after punching the green ceramic sheet, performing surface printing, lamination, upper and lower conductive bonding, cutting, sintering, and cooling to obtain the heat-resistant multi-layer ceramic substrate.

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