High-strength aluminum oxide multilayer ceramic substrate and preparation method thereof

Abstract

The invention relates to the technical field of ceramic substrates, and provides a high-strength aluminum oxide multilayer ceramic substrate and a preparation method thereof. The high-strength aluminum oxide multilayer ceramic substrate comprises the following components in parts by weight: 90-100 parts of aluminum oxide, 4-8 parts of a sintering aid, 3-6 parts of a plasticizer, 1-4 parts of a dispersing agent, 70-80 parts of a solvent and 2-5 parts of epoxy resin, the epoxy resin comprises first epoxy resin and second epoxy resin; the epoxy value of the first epoxy resin is 0.18 mol / 100g to 0.22 mol / 100g; and the epoxy value of the second epoxy resin is 0.70 mol / 100g to 0.74 mol / 100g. According to the technical scheme, the problem of low bending strength of the aluminum oxide multilayer ceramic substrate in the prior art is solved.

Description

Technical Field

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

[0002] As the electronic information industry moves toward high-density integration and high reliability, improving the mechanical properties of alumina multilayer ceramic substrates, a core supporting material for power electronics and hybrid integrated circuits, is crucial for breaking through bottlenecks in high-end electronic packaging technology. While traditional alumina ceramic substrates offer excellent electrical insulation and thermal stability, their inherent brittleness makes their bending strength insufficient for complex operating conditions.

[0003] The quality of the blank is one of the core internal factors that determine the bending strength of alumina ceramic substrates. In traditional preparation processes, the purity of the blank raw materials is insufficient, the particle size distribution is uneven, or the densification is incomplete during the sintering process, which easily forms defects such as pores, impurity phases, or abnormal grain growth inside the blank. These microscopic defects will become stress concentration points, significantly reducing the material's ability to withstand bending loads. When external loads act on the substrate, the defects are likely to induce crack initiation and expansion, leading to brittle fracture, and therefore poor bending strength performance. In addition, the density and grain uniformity of the blank directly affect the grain boundary bonding strength. Low-density or coarse-grained blanks are more likely to aggravate the mechanical weakness of the overall structure due to interface stress mismatch during the interlayer composite process. Therefore, breaking through the quality bottleneck of the blank preparation link and improving its intrinsic strength have become the primary technical path to solve the insufficient bending strength of alumina multilayer ceramic substrates. Summary of the Invention

[0004] The present invention provides a high-strength alumina multilayer ceramic substrate and a preparation method thereof, which solves the problem of low bending strength of the alumina multilayer ceramic substrate in the related art.

[0005] The technical solutions of the present invention are as follows: The present invention provides a high-strength alumina multilayer ceramic substrate, comprising the following components in parts by weight: 90-100 parts of alumina, 4-8 parts of a sintering aid, 3-6 parts of a plasticizer, 1-4 parts of a dispersant, 70-80 parts of a solvent, and 2-5 parts of an epoxy resin; The epoxy resin includes a first epoxy resin and a second epoxy resin; The epoxy value of the first epoxy resin is 0.18-0.22 mol / 100 g; The epoxy value of the second epoxy resin is 0.70-0.74 mol / 100g.

[0006] In the high-strength alumina multilayer ceramic substrate of the present invention, the plasticizer molecules can be inserted between the polymer molecular chains, weakening the interaction between the molecular chains, greatly increasing the flexibility and mobility of the molecular chains, and improving the rheological properties of the slurry during the preparation of the alumina multilayer ceramic substrate.

[0007] In the high-strength alumina multilayer ceramic substrate of the present invention, the dispersant reduces the surface tension of the alumina particles, prevents the particles from agglomerating, and realizes uniform dispersion of the alumina particles in the solvent.

[0008] As a further technical solution, the mass ratio of the first epoxy resin to the second epoxy resin is 7-9:4.

[0009] As a further technical solution, the mass ratio of the first epoxy resin to the second epoxy resin is 9:4.

[0010] In the present invention, the mass ratio of the first epoxy resin to the second epoxy resin can be 7:4, 7.1:4, 7.2:4, 7.3:4, 7.4:4, 7.5:4, 7.6:4, 7.7:4, 7.8:4, 7.9:4, 2:1, 8.1:4, 8.2:4, 8.3:4, 8.4:4, 8.5:4, 8.6:4, 8.8:4, 8.9:4, 9:4, and preferably 9:4.

[0011] In the present invention, when the mass ratio of the first epoxy resin to the second epoxy resin is 7 to 9:4, a basic network structure with a certain degree of flexibility can be established, and the interaction between the various components in the ceramic substrate can be enhanced, thereby further improving the overall quality of the blank and further improving the bending strength of the alumina multilayer ceramic substrate.

[0012] As a further technical solution, the sintering aid includes zinc oxide, silicon dioxide and tungsten oxide.

[0013] In the present invention, the sintering aids include zinc oxide, silicon dioxide and tungsten oxide. When the three metal oxides are used as sintering aids at the same time, zinc oxide, with its own low dielectric constant, promotes the growth and densification of aluminum oxide grains while being uniformly dispersed in the ceramic matrix, reducing local electric field concentration and lowering the degree of polarization, thereby laying the foundation for reducing the dielectric constant. Silicon dioxide has the ability to form a network and can construct a complex network structure with components such as aluminum oxide in the ceramic system. This network structure limits the range of electron movement. At the same time, the low dielectric constant characteristics of silicon dioxide itself help to reduce the dielectric constant of the entire ceramic. Tungsten oxide participates in the formation and adjustment of the ceramic lattice during the sintering process. Its special crystal structure and electron cloud distribution can affect the electron migration and polarization behavior inside the ceramic, thereby reducing the dielectric constant. The three produce a synergistic effect, reducing the dielectric constant of the high-strength alumina multilayer ceramic substrate.

[0014] As a further technical solution, the mass ratio of the zinc oxide to the silicon dioxide and to the tungsten oxide is 8:2-3.

[0015] In the present invention, the mass ratio of zinc oxide to silicon dioxide and to tungsten oxide is 4:1, 8:2.1, 8:2.2, 8:2.3, 8:2.4, 8:2.5, 8:2.6, 8:2.7, 8:2.8, 8:2.9, 8:3, preferably 8:3.

[0016] As a further technical solution, the mass ratio of zinc oxide to silicon dioxide is 4-5:1.

[0017] In the present invention, the mass ratio of zinc oxide to silicon dioxide is 4:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1, 5:1, and preferably 5:1.

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

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

[0020] As a further technical solution, the solvent includes one of toluene and xylene.

[0021] The present invention also provides a method for preparing a high-strength alumina multilayer ceramic substrate, which comprises the following steps: S1. Evenly mix alumina, a sintering aid, a plasticizer, a dispersant, and a solvent, and then add epoxy resin to obtain a slurry; S2, tape-casting the slurry and drying it to obtain a blank; S3. Punching the blank, performing surface printing, lamination, upper and lower conductive bonding, cutting, sintering, and cooling to obtain a high-strength alumina multilayer ceramic substrate.

[0022] The working principle and beneficial effects of the present invention are: In the present invention, a first and a second epoxy resin having epoxy values of 0.18-0.22 mol / 100 g and 0.70-0.74 mol / 100 g, respectively, are selected for compounding to improve the bending strength of the alumina multilayer ceramic substrate. Different from the prior art, the present invention pays attention to the important influence of the epoxy groups in the epoxy resin on the quality of the alumina multilayer ceramic substrate blank. The first epoxy resin with a lower epoxy value, due to its good molecular chain flexibility, is evenly distributed among the various components of the alumina multilayer ceramic substrate during tape casting, making the distribution of the various components of the sintered alumina multilayer ceramic substrate more uniform. When subjected to bending stress, stress concentration is effectively alleviated, brittle failure caused by stress is avoided, and toughness is imparted to the alumina multilayer ceramic substrate. The second epoxy resin with a higher epoxy value, due to the epoxy groups, can interact with the various components of the alumina multilayer ceramic substrate, making the bonding between the various components in the alumina multilayer ceramic substrate blank more compact, thereby efficiently transmitting and dispersing stress, ensuring that the entire substrate can jointly resist external forces, and significantly improving the bearing capacity of the substrate. The combination of the two epoxy resins produces a synergistic effect to improve the bending strength of the alumina multi-layer ceramic substrate. DETAILED DESCRIPTION

[0023] 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.

[0024] In the following examples and comparative examples, the epoxy value of the first epoxy resin is 0.18~0.22mol / 100g, the model is E-20 601, the epoxy value of the second epoxy resin is 0.70~0.74mol / 100g, the model is MHR-070, the weight average molecular weight of sodium polyacrylate is 10000, the particle size of zinc oxide is 50nm, the particle size of silicon dioxide is 50nm, and the particle size of tungsten oxide is 50nm.

[0025] Example 1 A high-strength alumina multilayer ceramic substrate comprises the following components in parts by weight: 100 parts of alumina, 8 parts of a sintering aid, 6 parts of tributyl citrate, 4 parts of sodium polyacrylate, 80 parts of toluene, and 5 parts of epoxy resin; The epoxy resin includes a first epoxy resin and a second epoxy resin in a mass ratio of 11:4; The sintering aid includes zinc oxide and silicon dioxide in a mass ratio of 1:1; A method for preparing a high-strength alumina multilayer ceramic substrate comprises the following steps: S1. Mix alumina, sintering aid, tributyl citrate, sodium polyacrylate, and toluene, and then add epoxy resin to obtain a slurry; S2, tape-casting the slurry and drying it to obtain a blank; S3, punching the blank, performing surface printing, lamination, upper and lower conductive processes, cutting, sintering at 1650° C., and cooling to obtain a high-strength alumina multilayer ceramic substrate; The raw material for surface printing is tungsten paste, and the printing thickness is 15μm; The number of layers of the high-strength alumina ceramic substrate is 30.

[0026] Example 2 A high-strength alumina multilayer ceramic substrate comprises the following components in parts by weight: 90 parts alumina, 4 parts sintering aid, 1 part dibutyl phthalate, 2 parts dioctyl phthalate, 1 part dibutyl phosphate, 70 parts xylene, and 2 parts epoxy resin; The epoxy resin includes a first epoxy resin and a second epoxy resin in a mass ratio of 3:2; The sintering aid includes zinc oxide and silicon dioxide in a mass ratio of 1:1; A method for preparing a high-strength alumina multilayer ceramic substrate comprises the following steps: S1. Evenly mix alumina, a sintering aid, dibutyl phthalate, dioctyl phthalate, dibutyl phosphate, and xylene, and then add epoxy resin to obtain a slurry; S2, tape-casting the slurry and drying it to obtain a blank; S3, punching the blank, performing surface printing, lamination, upper and lower conductive processes, cutting, sintering at 1650° C., and cooling to obtain a high-strength alumina multilayer ceramic substrate; The raw material for surface printing is tungsten paste, and the printing thickness is 15μm; The number of layers of the high-strength alumina ceramic substrate is 30.

[0027] Example 3 The only difference between this embodiment and embodiment 2 is that the mass ratio of the first epoxy resin to the second epoxy resin in this embodiment is 5:2.

[0028] Example 4 The only difference between this embodiment and embodiment 2 is that the mass ratio of the first epoxy resin to the second epoxy resin in this embodiment is 7:4.

[0029] Example 5 The only difference between this embodiment and embodiment 2 is that the mass ratio of the first epoxy resin to the second epoxy resin in this embodiment is 9:4.

[0030] Example 6 The only difference between this embodiment and Example 5 is that the sintering aid in this embodiment is replaced by a three-component composite sintering aid of equal mass, and the three-component composite sintering aid includes zinc oxide, silicon dioxide and tungsten oxide; the mass ratio of zinc oxide to silicon dioxide and to tungsten oxide is 8:3, and the mass ratio of zinc oxide to silicon dioxide is 1:1.

[0031] Example 7 The only difference between this embodiment and embodiment 6 is that in this embodiment, the mass ratio of zinc oxide to silicon dioxide and to tungsten oxide is 4:1, and the mass ratio of zinc oxide to silicon dioxide is 1:1.

[0032] Example 8 The only difference between this embodiment and embodiment 7 is that the mass ratio of zinc oxide to silicon dioxide in this embodiment is 4:1.

[0033] Example 9 The only difference between this embodiment and embodiment 7 is that the mass ratio of zinc oxide to silicon dioxide in this embodiment is 5:1.

[0034] Comparative Example 1 The only difference between this comparative example and Example 2 is that the epoxy resin in this comparative example is only the first epoxy resin.

[0035] Comparative Example 2 The only difference between this comparative example and Example 2 is that the epoxy resin in this comparative example is only the second epoxy resin.

[0036] Comparative Example 3 The only difference between this comparative example and Example 2 is that no epoxy resin is added in this comparative example.

[0037] Experimental Example 1 The high-strength alumina multilayer ceramic substrates prepared in Examples 1-5 and Comparative Examples 1-3 were tested for flexural strength using the 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.

[0038] Table 1 Bending strength test results

[0039] As shown in Table 1, the flexural strength of the high-strength alumina multilayer ceramic substrates prepared in Examples 1 to 5 of the present invention reaches above 400 MPa. Therefore, the present invention uses two epoxy resins with different epoxy values to synergistically improve the flexural strength of the alumina multilayer ceramic substrate.

[0040] Experimental Example 2 The high-strength alumina multilayer ceramic substrates prepared in Examples 5-9 were tested for dielectric constant according to the method specified in GB / T 5594.4-2015, "Test Methods for Properties of Structural Ceramics for Electronic Components - Part 4: Test Method for Dielectric Constant and Dielectric Loss Tangent." The test results are shown in Table 2.

[0041] Table 2 Dielectric constant test results

[0042] As can be seen from Table 2, the dielectric constants of Examples 6 to 7 of the present invention reached below 4.5, indicating that the mass ratio of zinc oxide to silicon dioxide and to tungsten oxide is limited to 8:2 to 3 in the present invention, thereby reducing the dielectric constant. The dielectric constants of Examples 8 to 9 of the present invention reached below 3.8, indicating that the dielectric constant can be further reduced by further limiting the mass ratio of zinc oxide to silicon dioxide to 4 to 5:1 on the basis of the mass ratio of zinc oxide to silicon dioxide and to tungsten oxide being 8:2 to 3 in the present invention.

[0043] 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. High-strength alumina multilayer ceramic substrate, characterized in that, The invention comprises the following components in parts by weight: 90-100 parts of aluminum oxide, 4-8 parts of sintering aid, 3-6 parts of plasticizer, 1-4 parts of dispersant, 70-80 parts of solvent, and 2-5 parts of epoxy resin; The epoxy resin includes a first epoxy resin and a second epoxy resin; The epoxy value of the first epoxy resin is 0.18-0.22 mol / 100 g; The epoxy value of the second epoxy resin is 0.70-0.74 mol / 100g.

2. The high-strength alumina multilayer ceramic substrate according to claim 1, characterized in that: The mass ratio of the first epoxy resin to the second epoxy resin is 7-9:

4.

3. The high-strength alumina multilayer ceramic substrate according to claim 2, characterized in that: The mass ratio of the first epoxy resin to the second epoxy resin is 9:

4.

4. The high-strength alumina multilayer ceramic substrate according to claim 1, characterized in that: The sintering aids include zinc oxide, silicon dioxide and tungsten oxide.

5. The high-strength alumina multilayer ceramic substrate according to claim 4, characterized in that: The mass ratio of the zinc oxide to the silicon dioxide and to the tungsten oxide is 8:2-3.

6. The high-strength alumina multilayer ceramic substrate according to claim 5, characterized in that: The mass ratio of zinc oxide to silicon dioxide is 4-5:

1.

7. The high-strength alumina multilayer ceramic substrate according to claim 1, characterized in that: The plasticizer includes one or more of dibutyl phthalate, dioctyl phthalate, and tributyl citrate.

8. The high-strength alumina multilayer ceramic substrate according to claim 1, characterized in that: The dispersant includes one of sodium polyacrylate and dibutyl phosphate.

9. The high-strength alumina multilayer ceramic substrate according to claim 1, characterized in that: The solvent includes one of toluene and xylene.

10. A method for preparing a high-strength alumina multilayer ceramic substrate, for preparing the high-strength alumina multilayer ceramic substrate according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Evenly mix alumina, a sintering aid, a plasticizer, a dispersant, and a solvent, and then add epoxy resin to obtain a slurry; S2, tape-casting the slurry and drying it to obtain a blank; S3, punching the blank, performing surface printing, lamination, upper and lower conductive bonding, cutting, sintering, and cooling to obtain a high-strength alumina multilayer ceramic substrate.

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