A high-strength multi-layer ceramic substrate and a preparation method thereof

Abstract

The present invention relates to the technical field of ceramic materials, and provides a high-strength multi-layer ceramic substrate and a preparation method thereof. The high-strength multi-layer ceramic substrate comprises raw materials with the following parts by weight: 70-90 parts of alumina, 1-3 parts of dispersant, 4-8 parts of binder, 1-3 parts of plasticizer, 10-15 parts of auxiliary agent, and 60-70 parts of water; the auxiliary agent is titanium diboride, magnesium fluoride, and cerium oxide; the mass ratio of titanium diboride, magnesium fluoride, and cerium oxide is 1:3:1-5. Through the above technical solution, the problem of low strength of multi-layer ceramic substrates in the related art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic materials, and specifically, to a high-strength multi-layer ceramic substrate and a preparation method thereof. Background Art

[0002] In the wave of the rapid development of modern electronic technology, various electronic devices are striding forward towards miniaturization, high performance, and high integration. This trend poses extremely stringent performance requirements for the key basic components inside electronic devices - ceramic substrates. Traditional single-layer ceramic substrates, due to their simple structure, have become inadequate when facing the current complex electronic circuit layout requirements. On the one hand, their limited number of wiring layers severely restricts the improvement of the integration of electronic devices and cannot meet the needs of high-density assembly of a large number of electronic components. On the other hand, single-layer ceramic substrates have inherent defects in strength. When subjected to large external force impacts or stresses caused by thermal expansion and contraction, they are extremely prone to cracks or even fractures, greatly affecting the reliability and service life of electronic devices.

[0003] To solve the above problems, multi-layer ceramic substrates have emerged. Multi-layer ceramic substrates achieve multi-layer wiring of circuits by laminating and sintering multiple ceramic layers, significantly improving the integration of electronic devices. However, there are still many challenges in the strength of multi-layer ceramic substrates on the market at present. Although compared with single-layer ceramic substrates, when a multi-layer ceramic substrate is subjected to an external force, the force will be transmitted and dispersed between the layers, and the strength of the multi-layer ceramic substrate has been improved to a certain extent. However, due to the influence of preparation methods or additives, there are inevitably some pores in the ceramic substrate, resulting in a decrease in strength, thus unable to meet the requirements for the strength of the ceramic substrate during use to a high degree. Summary of the Invention

[0004] The present invention provides a high-strength multi-layer ceramic substrate and a preparation method thereof, which solve the problem of low strength of multi-layer ceramic substrates in related technologies.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a high-strength multi-layer ceramic substrate, comprising raw materials in the following parts by weight: 70 - 90 parts of alumina, 1 - 3 parts of dispersant, 4 - 8 parts of binder, 1 - 3 parts of plasticizer, 10 - 15 parts of auxiliary agent, and 60 - 70 parts of water; the auxiliary agent is titanium diboride, magnesium fluoride, and cerium oxide; the mass ratio of titanium diboride, magnesium fluoride, and cerium oxide is 1:3:1 - 5.

[0007] As a further technical solution, the cerium oxide includes cerium trioxide and cerium dioxide.

[0008] In the present invention, cerium oxides composed of cerium sesquioxide and cerium dioxide are used as additives. During the sintering process, cerium atoms in cerium sesquioxide and cerium dioxide have variable oxidation states. In the grain boundary environment, they can undergo electron cloud interaction with other atoms in the ceramic substrate. Due to the irregular arrangement of atoms at the grain boundaries, there are many vacancies, dislocations and other defects, and the energy is relatively high. After the segregation of cerium oxides, oxygen atoms in their structure can combine with unsaturated bonds at the grain boundaries, and cerium atoms can adjust the charge distribution between atoms through electron exchange with surrounding atoms, reducing the free energy of the grain boundary region; after the grain boundary energy is reduced, the diffusion rate of atoms at the grain boundaries changes, and the atomic movement that was originally active due to high energy is inhibited, and the migration and deformation of the grain boundaries are restricted, thereby making the grain boundaries more stable. Ce 3+ and Ce 4+ The variable valence characteristics of, promote surrounding atoms to fill vacancies and reduce the dislocation density, further optimizing the grain boundary structure.

[0009] As a further technical solution, the mass ratio of the cerium sesquioxide to the cerium dioxide is 2:2 to 5, for example, it can be 1:1, 2:3, 2:4, 2:5.

[0010] As a further technical solution, the particle size of the cerium sesquioxide is 10 to 90 nm; the particle size of the cerium dioxide is 10 to 50 nm.

[0011] In the present invention, the particle sizes of both cerium sesquioxide and cerium dioxide are in the nanometer range. Because nano-cerium oxides have a relatively large specific surface area, the cerium atoms on the surface are connected to fewer oxygen atoms, so there are more unsatisfied chemical bond requirements. This makes the surface atoms in a high-energy unstable state. To reduce their own energy and reach a stable state, when the cerium oxides are mixed with alumina, the cerium atoms and oxygen atoms on the surface are more likely to form new chemical bonds with the oxygen atoms in the alumina lattice, triggering electron interaction. Therefore, in a high-temperature environment, the ceramic substrate added with nano-cerium sesquioxide and cerium dioxide can maintain good mechanical properties and structural integrity.

[0012] As a further technical solution, the particle size of the titanium diboride is 10 to 50 nm, for example, it can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, and preferably 20 nm;

[0013] The particle size of the magnesium fluoride is 50 to 90 nm, for example, it can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, and preferably 50 nm.

[0014] As a further technical solution, the dispersant includes one or more of ammonium polyacrylate, castor oil, and stearic acid.

[0015] In the present invention, the addition of the dispersant effectively improves the dispersion effect of the ceramic substrate raw materials in water. One end of the dispersant is hydrophilic and the other end is lipophilic. The lipophilic end adsorbs on the surface of solid particles through van der Waals forces, and the hydrophilic groups enter the water, greatly reducing the interfacial tension between the solid particles and water. The dispersant adsorbed on the surface of solid particles also forms a relatively stable molecular layer, preventing the particles from aggregating excessively and maintaining a dispersed state, enabling the solid particles to be evenly dispersed in water, thereby improving the uniformity of the overall material and reducing performance defects caused by uneven dispersion.

[0016] As a further technical solution, the binder includes one or two of polyvinyl butyral and sodium carboxymethyl cellulose.

[0017] In the present invention, from a microscopic perspective, the binder molecules have unique chemical structures and physical properties. For example, in polyvinyl butyral, there are a large number of hydroxyl groups and butyraldehyde groups in its molecular structure, and the hydroxyl groups can form hydrogen bonds with the active sites on the surface of alumina; the sodium carboxymethyl cellulose molecule contains carboxymethyl groups, which ionize in an aqueous solution environment and adsorb to alumina through electrostatic interactions; at the same time, the molecular chains in the binder form a continuous network structure in the system through mutual entanglement, improving the binding force between powder particles, and this network structure has a certain flexibility and elasticity, which can buffer external forces to a certain extent, thereby improving the overall strength of the ceramic substrate.

[0018] As a further technical solution, the plasticizer includes one or more of dibutyl phthalate, dioctyl phthalate, and polyvinyl alcohol.

[0019] In the present invention, plasticizer molecules usually have relatively small molecular weights and good flexibility. During the mixing stage before the forming of the green body, the plasticizer molecules gradually disperse in the gaps between the powder particles. Through processing, these molecules form a flexible connecting medium between the powder particles. The flexible connecting medium can improve the bending resistance of the green body. When the green body bears a bending force, the flexible connecting medium can buffer and disperse the external force, enabling the green body to better adapt to the change of the external force, avoiding excessive concentration of stress in a local area, resulting in cracks or fractures in the green body, and ensuring the final yield and quality of the ceramic substrate.

[0020] The present invention also proposes a preparation method for a high-strength multi-layer ceramic substrate for preparing the high-strength multi-layer ceramic substrate, including the following steps:

[0021] S1. After mixing the raw materials, a ceramic green sheet is obtained through defoaming, casting, and drying.

[0022] S2. After punching, surface printing, laminating, through-hole conduction, and cutting the ceramic green sheet, sintering is carried out to obtain a high-strength multi-layer ceramic substrate.

[0023] The sintering atmosphere is one or both of argon and helium.

[0024] As a further technical solution, in step S1, the mixing is specifically as follows: alumina is first ball-milled with magnesium fluoride and cerium oxide, titanium diboride is added for the second ball-milling, and the remaining raw materials are added for the third ball-milling.

[0025] In the present invention, by mixing the raw materials in three times, first ball-milling alumina with magnesium fluoride and cerium oxide, then adding titanium diboride for ball-milling, and finally adding the remaining raw materials for ball-milling, the raw materials can be better combined, improving the strength of the ceramic substrate; among them, magnesium fluoride has the functions of reducing the sintering temperature and improving the microstructure, and cerium oxide can optimize the grain boundary structure of alumina. By mixing the two with alumina first, the effect on alumina can be better achieved. Then, when adding titanium diboride for mixing, titanium diboride can be embedded into the gaps between alumina particles, enhancing the interaction between the raw materials. Finally, adding the remaining other raw materials enables the other raw materials to further fill the pores, making the combination between the raw materials more compact and uniform. During the sintering process of the ceramic substrate, a denser microstructure can be formed, thereby improving the strength of the ceramic substrate.

[0026] As a further technical solution, the rotation speed of the first ball-milling is 2000 - 3000 r / min, and the time of the first ball-milling is 0.5 - 1 h; the rotation speed of the second ball-milling is 800 - 1000 r / min, and the time of the second ball-milling is 0.5 - 1 h; the rotation speed of the third ball-milling is 400 - 500 r / min, and the time of the third ball-milling is 1 - 2 h.

[0027] In the present invention, alumina, magnesium fluoride, and cerium oxide particles are ball-milled at a rotation speed of 2000 - 3000 r / min. Through high-speed ball-milling, the collision frequency between particles is greatly increased, large particles can be quickly broken into small particles, the specific surface area of the particles is greatly increased, the electron cloud distribution changes, forming more active sites, promoting the subsequent combination with other raw materials. After adding titanium diboride, it is ball-milled at a rotation speed of 800 - 1000 r / min. The lower rotation speed enables the titanium diboride particles to more gently and orderly embed into the gaps between the particles of the previous mixture when contacting the previous mixture. If the rotation speed is too high, the excessive impact force generated will damage the structure formed by the previous mixture and they cannot be well combined together; after adding the remaining raw materials, it is ball-milled at a rotation speed of 400 - 500 r / min. The low rotation speed enables the remaining raw materials to slowly and evenly diffuse and distribute in the already formed relatively compact mixing system, making the entire mixing system highly uniform microscopically, thereby improving the consistency of the ceramic substrate.

[0028] As a further technical solution, the sintering includes first sintering and second sintering; the first sintering is hot-press sintering; the second sintering is pressureless sintering.

[0029] In the present invention, in a high-temperature environment, the atomic activity of particles such as alumina is significantly enhanced, and the diffusion rate of atoms is accelerated. At the same time, the externally applied pressure causes these particles with enhanced activity to move rapidly and approach each other, capable of quickly filling the pores inside the green body, greatly improving the density of the ceramic substrate, enabling the green body to reach a high density and form in a short time; however, hot-press sintering will generate internal stress inside the ceramic substrate, easily causing cracks in the ceramic and reducing the strength of the ceramic substrate. Therefore, pressureless sintering is adopted for the second time. In a high-temperature environment, the atoms inside the ceramic can release the internal stress generated by hot-press sintering through diffusion and rearrangement. The two sintering methods cooperate with each other, and the synergistic effect comprehensively optimizes the ceramic substrate in terms of density, microstructure stability, and grain boundary bonding force, thereby significantly improving the strength of the ceramic substrate.

[0030] As a further technical solution, the pressure of the hot-press sintering is 10 - 20 MPa, the temperature of the hot-press sintering is 500 - 600 °C, and the time of the hot-press sintering is 2 - 3 h;

[0031] As a further technical solution, the temperature of the pressureless sintering is 1200 - 1500 °C, and the time of the pressureless sintering is 8 - 10 h.

[0032] As a further technical solution, after the pressureless sintering, it is cooled to room temperature, and the cooling rate is 10 - 30 °C / min.

[0033] In the present invention, after sintering, it is cooled at a rate of 10 - 30 °C / min. Atoms have enough time to diffuse and arrange in the crystal lattice, thereby forming grains with relatively uniform sizes, and the formation of grain boundaries will also be more regular and uniform. This uniform grain growth and grain boundary formation method enables the stress to be evenly distributed throughout the material when the ceramic substrate bears external forces, effectively avoiding the stress concentration phenomenon caused by uneven grain sizes or grain boundary defects, thereby improving the strength and toughness of the ceramic substrate. If the cooling rate is lower than 10 °C / min, in a long-term high-temperature environment, impurity atoms will diffuse at the grain boundaries, changing the chemical composition and structure of the grain boundaries and reducing the bonding strength of the grain boundaries; if the cooling rate is higher than 30 °C / min, large thermal stress will be generated inside the ceramic substrate due to the rapid temperature change, resulting in lattice defects and stress concentration points, thereby reducing the strength and toughness of the ceramic.

[0034] The working principle and beneficial effects of the present invention are:

[0035] In the present invention, alumina is used as the main component, providing good basic strength and stability for the ceramic substrate. In the additives, titanium diboride, magnesium fluoride, and cerium oxide are combined in a mass ratio of 1:3:1 to 5, playing a synergistic role during the sintering process. Titanium diboride can promote the uniform growth of alumina grains, inhibit abnormal growth, optimize the microstructure, and reduce the pores between grains; magnesium fluoride can lower the sintering temperature, accelerate the mass diffusion rate, and improve the sintering density; cerium oxide can purify the grain boundaries, reduce the influence of impurities, enhance the grain boundary bonding force, and reduce the pores. The three work together to greatly improve the sintering quality of the ceramic substrate, significantly increasing its density and reducing the internal pores, thereby greatly enhancing the strength of the substrate. Detailed implementation mode

[0036] The following will describe the technical solutions in the embodiments of the present invention clearly and completely 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 protection of the present invention.

[0037] In the following embodiments and comparative examples:

[0038] Ammonium polyacrylate, MW: 30 million; polyvinyl butyral, model: B60H; sodium carboxymethyl cellulose, viscosity 1000 mPa·s; the particle size of alumina is 75 μm.

[0039] Example 1

[0040] A method for preparing a high-strength multi-layer ceramic substrate includes the following steps:

[0041] S1. Mix 70 parts of alumina, 1 part of ammonium polyacrylate, 4 parts of polyvinyl butyral, 1 part of dibutyl phthalate, 10 parts of additives, and 60 parts of water by ball milling at a rotation speed of 400 r / min for 2 h, and then obtain a ceramic green sheet through defoaming, casting, and drying.

[0042] S2. Punch, surface print, laminate, conduct upper and lower connections, cut the ceramic green sheet, and sinter it in an argon atmosphere at 1500 °C for 10 h, and then cool it to room temperature at a rate of 10 °C / min to obtain a multi-layer ceramic substrate.

[0043] The additives are composed of titanium diboride (20 nm), magnesium fluoride (50 nm), and cerium oxide with a mass ratio of 1:3:1; the cerium oxide is composed of cerium dioxide (30 nm) and cerium sesquioxide (50 nm) with a mass ratio of 1:1.

[0044] Example 2

[0045] A preparation method of a high-strength multi-layer ceramic substrate, comprising the following steps:

[0046] S1. Mix 90 parts of alumina, 3 parts of stearic acid, 8 parts of sodium carboxymethyl cellulose, 3 parts of dioctyl phthalate, 15 parts of an additive, and 70 parts of water by ball milling at a rotation speed of 500 r / min for 1 h, then obtain a ceramic green sheet through defoaming, doctor blading, and drying.

[0047] S2. Punch, surface print, stack and laminate, conduct upper and lower conduction, cut the ceramic green sheet, sinter it in an argon atmosphere at 1200 °C for 13 h, and then cool it to room temperature at a rate of 30 °C / min to obtain a multi-layer ceramic substrate.

[0048] The additive is composed of titanium diboride (20 nm), magnesium fluoride (50 nm), and cerium oxide with a mass ratio of 1:3:5; the cerium oxide is composed of cerium dioxide (30 nm) and cerium trioxide (50 nm) with a mass ratio of 2:5.

[0049] Example 3

[0050] Compared with Example 1, the difference in this example is only that the preparation method of the ceramic green sheet is as follows: Mix 70 parts of alumina and 10 parts of an additive by ball milling at a rotation speed of 2000 r / min for 1 h, then add 1 part of ammonium polyacrylate, 4 parts of polyvinyl butyral, 1 part of dibutyl phthalate, and 60 parts of water, and continue to ball mill and mix at a rotation speed of 400 r / min for 1 h, and obtain a ceramic green sheet through defoaming, doctor blading, and drying.

[0051] The additive is composed of titanium diboride (20 nm), magnesium fluoride (50 nm), and cerium oxide with a mass ratio of 1:3:1; the cerium oxide is composed of cerium dioxide (30 nm) and cerium trioxide (50 nm) with a mass ratio of 1:1.

[0052] Example 4

[0053] Compared with Example 1, the difference in this example is only that the preparation method of the ceramic green sheet is as follows: Mix 70 parts of alumina and 2 parts of titanium diboride (20 nm) by ball milling at a rotation speed of 2000 r / min for 0.5 h, add 6 parts of magnesium fluoride (50 nm) and 2 parts of cerium oxide, and ball mill and mix at a rotation speed of 800 r / min for 0.5 h, then add 1 part of ammonium polyacrylate, 4 parts of polyvinyl butyral, 1 part of dibutyl phthalate, and 60 parts of water, and continue to ball mill and mix at a rotation speed of 400 r / min for 1 h, and obtain a ceramic green sheet through defoaming, doctor blading, and drying.

[0054] The cerium oxide is composed of cerium dioxide (30 nm) and cerium trioxide (50 nm) with a mass ratio of 1:1.

[0055] Example 5

[0056] Compared with Example 1, the only difference in this example is that the preparation method of the ceramic green sheet is as follows: 70 parts of alumina, 6 parts of magnesium fluoride (50 nm), and 2 parts of cerium oxide are ball-milled and mixed at a rotation speed of 2000 r / min for 0.5 h, 2 parts of titanium diboride (20 nm) are added and ball-milled and mixed at a rotation speed of 800 r / min for 0.5 h, then 1 part of ammonium polyacrylate, 4 parts of polyvinyl butyral, 1 part of dibutyl phthalate, and 60 parts of water are added and continuously ball-milled and mixed at a rotation speed of 400 r / min for 1 h, and the ceramic green sheet is obtained through defoaming, casting, and drying;

[0057] The cerium oxide is composed of cerium dioxide (30 nm) and cerium sesquioxide (50 nm) with a mass ratio of 1:1.

[0058] Example 6

[0059] Compared with Example 1, the only difference in this example is that the preparation method of the ceramic green sheet is as follows: 70 parts of alumina, 6 parts of magnesium fluoride (50 nm), and 2 parts of cerium oxide are ball-milled and mixed at a rotation speed of 800 r / min for 0.5 h, 2 parts of titanium diboride (20 nm) are added and ball-milled and mixed at a rotation speed of 2000 r / min for 0.5 h, then 1 part of ammonium polyacrylate, 4 parts of polyvinyl butyral, 1 part of dibutyl phthalate, and 60 parts of water are added and continuously ball-milled and mixed at a rotation speed of 400 r / min for 1 h, and the ceramic green sheet is obtained through defoaming, casting, and drying;

[0060] The cerium oxide is composed of cerium dioxide (30 nm) and cerium sesquioxide (50 nm) with a mass ratio of 1:1.

[0061] Example 7

[0062] A preparation method of a high-strength multi-layer ceramic substrate includes the following steps:

[0063] S1. The preparation method of the ceramic green sheet is the same as that in Example 5;

[0064] S2. The ceramic green sheet is punched, surface-printed, laminated and pressed, conductively connected up and down, cut, sintered in an argon atmosphere at 500 °C for 2 h, sintered at 1300 °C for 8 h, and then cooled to room temperature at a rate of 10 °C / min to obtain the multi-layer ceramic substrate.

[0065] Example 8

[0066] A preparation method of a high-strength multi-layer ceramic substrate includes the following steps:

[0067] S1. The preparation method of the ceramic green sheet is the same as that in Example 5;

[0068] S2. Subject the ceramic green sheet to punching, surface printing, laminated lamination, upper and lower conduction, cutting, sinter at 500 °C for 2 h under an argon atmosphere with a pressure of 10 MPa, sinter at 1300 °C for 8 h, and then cool down to room temperature at a rate of 10 °C / min to obtain a multilayer ceramic substrate.

[0069] Example 9

[0070] A preparation method of a high-strength multilayer ceramic substrate, comprising the following steps:

[0071] S1. The preparation method of the ceramic green sheet is the same as that in Example 5;

[0072] S2. Subject the ceramic green sheet to punching, surface printing, laminated lamination, upper and lower conduction, cutting, sinter at 500 °C for 2 h under an argon atmosphere, sinter at 1300 °C under a pressure of 10 MPa for 8 h, and then cool down to room temperature at a rate of 10 °C / min to obtain a multilayer ceramic substrate.

[0073] Comparative Example 1

[0074] Compared with Example 1, the difference in this comparative example is only that the additive is only titanium diboride (20 nm).

[0075] Comparative Example 2

[0076] Compared with Example 1, the difference in this comparative example is only that the additive is only magnesium fluoride (50 nm).

[0077] Comparative Example 3

[0078] Compared with Example 1, the difference in this comparative example is only that the additive is only cerium dioxide (30 nm).

[0079] Comparative Example 4

[0080] Compared with Example 1, the difference in this comparative example is only that the additive is only cerium sesquioxide (50 nm).

[0081] Comparative Example 5

[0082] Compared with Example 1, the difference in this comparative example is only that the additive is composed of titanium diboride (20 nm) and magnesium fluoride (50 nm) with a mass ratio of 1:3.

[0083] Comparative Example 6

[0084] Compared with Example 1, the difference in this comparative example is only that the additive is composed of titanium diboride (20 nm) and cerium dioxide (30 nm) with a mass ratio of 1:1.

[0085] Comparative Example 7

[0086] This comparative example is different from Example 1 only in that titanium diboride (20 nm) is replaced with an equal amount of titanium dioxide (20 nm).

[0087] Experimental Example 1

[0088] The multi-layer ceramic substrates prepared in Examples 1 to 9 and Comparative Examples 1 to 7 were tested for flexural strength according to the test method (three-point bending method) specified in GB / T 6569-2006 "Test Method for Flexural Strength of Fine Ceramics". The test results are shown in Table 1.

[0089] Table 1 Test Results of Flexural Strength of Multi-layer Ceramic Substrates

[0090]

[0091] Compared with Comparative Examples 1 to 7, the ceramic substrates prepared in Examples 1 to 2 had higher flexural strength, indicating that when the additives consisted of titanium diboride, magnesium fluoride, cerium trioxide, and cerium dioxide, the flexural strength of the ceramic substrate could be improved.

[0092] Comparing Examples 3 to 6, it was found that the ceramic substrate prepared in Example 5 had higher flexural strength, indicating that when alumina was first ball-milled and mixed with magnesium fluoride and cerium oxide at 2000 r / min, and then titanium diboride was added and ball-milled at 800 r / min, the flexural strength of the ceramic substrate could be further improved.

[0093] Comparing Examples 7 to 9, it turned out that the ceramic substrate prepared in Example 8 had higher flexural strength, indicating that using pressure sintering for the first sintering and non-pressure sintering for the second sintering could further improve the flexural strength of the ceramic substrate and better meet the strength requirements of the ceramic substrate during use.

[0094] Experimental Example 2

[0095] The ceramic substrates prepared in Examples 1 to 2 were measured for dielectric constant at 10 GHz according to the method in GB / T 12636-1990 "Test Method for Complex Dielectric Constant of Microwave Dielectric Substrates by Stripline", and the fracture toughness was measured according to the method in GB / T 23806-2009 "Test Method for Fracture Toughness of Fine Ceramics - Single-edge Pre-cracked Beam (SEPB) Method". The test results are shown in Table 2.

[0096] Table 2 Test Results of Dielectric Constant and Fracture Toughness of Ceramic Substrates

[0097]

[0098] As can be seen from Table 2, the dielectric constant of the ceramic substrates prepared in Examples 1 to 2 was ≤8.35, and the fracture toughness was ≥9.3 MPa·m 1 / 2, meeting the usage requirements of the ceramic substrate and having a wide range of applications.

[0099] 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 principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-strength multi-layer ceramic substrate, characterized in that, Raw materials including the following components by weight: 70-90 parts of alumina, 1-3 parts of dispersant, 4-8 parts of binder, 1-3 parts of plasticizer, 10-15 parts of auxiliary agent, and 60-70 parts of water; the auxiliary agent is titanium boride, magnesium fluoride, and cerium oxide; the mass ratio of titanium boride, magnesium fluoride, and cerium oxide is 1:3:1-5; The preparation method of the high-strength multi-layer ceramic substrate includes the following steps: S1. After mixing the raw materials, perform degassing, casting, and drying to obtain a ceramic green sheet; S2. Punch, surface print, laminate, conduct top and bottom, and cut the ceramic green sheet, and then sinter to obtain a high-strength multi-layer ceramic substrate; In step S2, the sintering atmosphere is one or two of argon and helium; In step S1, the mixing is specifically as follows: first ball-mill alumina with magnesium fluoride and cerium oxide, add titanium boride for the second ball-milling, and add the remaining raw materials for the third ball-milling.

2. The high-strength multi-layer ceramic substrate according to claim 1, characterized in that, The cerium oxide includes cerium sesquioxide and cerium dioxide.

3. A high-strength multi-layer ceramic substrate according to claim 1, characterized in that, The mass ratio of cerium sesquioxide to cerium dioxide is 2:2-5.

4. A high-strength multi-layer ceramic substrate according to claim 3, characterized in that, The particle size of cerium sesquioxide is 10-90 nm; the particle size of cerium dioxide is 10-50 nm.

5. A high-strength multi-layer ceramic substrate according to claim 1, wherein, The rotation speed of the first ball-milling is 2000-3000 r / min, and the time of the first ball-milling is 0.5-1 h; the rotation speed of the second ball-milling is 800-1000 r / min, and the time of the second ball-milling is 0.5-1 h; the rotation speed of the third ball-milling is 400-500 r / min, and the time of the third ball-milling is 1-2 h.

6. A high-strength multi-layer ceramic substrate according to claim 1, wherein, The sintering includes first sintering and second sintering; the first sintering is hot-press sintering; the second sintering is pressureless sintering.

7. The high-strength multi-layer ceramic substrate according to claim 6, wherein, The pressure of the hot-press sintering is 10-20 MPa, the temperature of the hot-press sintering is 500-600 °C, and the time of the hot-press sintering is 2-3 h; The temperature of the pressureless sintering is 1200-1500 °C, and the time of the pressureless sintering is 8-10 h.

8. A high-strength multi-layer ceramic substrate according to claim 6, characterized in that, After the pressureless sintering, cool down to room temperature, and the cooling rate is 10-30 °C / min.

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