High hardness alumina multilayer ceramic substrate

Abstract

The application relates to the technical field of ceramic substrates, and discloses a high-hardness alumina multilayer ceramic substrate which comprises the following components in parts by weight: modified alumina 100 parts, silicate 10-15 parts, sintering aid 5-8 parts, dispersant 2-5 parts, binder 6-8 parts and solvent 80 parts; the raw material of the modified alumina comprises alumina and a modifier in a weight ratio of 50:3-6; the modifier comprises polylactic acid and boron trioxide. Through the technical scheme, the problem of poor fracture toughness of the alumina multilayer ceramic substrate in the related art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic substrate, in particular, relates to high hardness alumina multilayer ceramic substrate. BACKGROUND

[0002] Alumina ceramic substrate is widely used in electronic devices, integrated circuits, power modules, LED packaging and other high-end technical fields due to its excellent high-temperature stability, good insulation performance, high mechanical strength and chemical stability. With the development of electronic equipment towards high performance, high integration and miniaturization, higher requirements are put forward for the performance of ceramic substrate.

[0003] Alumina is the main ceramic material of alumina ceramic substrate, and its own performance directly affects the performance advantage of alumina multilayer ceramic substrate. Alumina itself has high hardness and can provide good basic support for ceramic substrate, but the fracture toughness of alumina material is relatively low, which limits its application in harsh environment. In order to improve the fracture toughness of alumina material, the second phase reinforcing body (such as silicon carbide, zirconium oxide, etc.) is usually added. However, the second phase reinforcing body directly added has the defect of insufficient bonding force with the matrix, which limits the improvement of the toughening effect of alumina material, and thus the fracture toughness of alumina ceramic substrate is not improved.

[0004] Therefore, it is important to develop a high hardness alumina multilayer ceramic substrate which can effectively improve the fracture toughness, so as to improve the crack resistance and prolong the service life of the alumina multilayer ceramic substrate. SUMMARY

[0005] The present application provides a high hardness alumina multilayer ceramic substrate, which solves the problem of poor fracture toughness of alumina multilayer ceramic substrate in the related art.

[0006] The technical scheme of the present application is as follows:

[0007] The present application provides a high hardness alumina multilayer ceramic substrate, which includes the following components by weight:

[0008] Modified alumina 100 parts, silicate 10-15 parts, sintering aid 5-8 parts, dispersant 2-5 parts, binder 6-8 parts, solvent 80 parts;

[0009] The raw material of the modified alumina includes alumina and modifier in a weight ratio of 50:3-6.

[0010] The modifier includes polylactic acid and boron trioxide.

[0011] As a further technical solution, the weight ratio of the polylactic acid and the boron trioxide is 2-5:1.

[0012] In the high-hardness alumina multilayer ceramic substrate, by optimizing the content ratio of the polylactic acid and the boron trioxide, when the weight ratio of the polylactic acid and the boron trioxide is 2-5:1, the fracture toughness of the alumina multilayer ceramic substrate can be further improved, and the fracture toughness is increased to 12.3MPa·m 1 / 2 The above.

[0013] As a further technical solution, the preparation method of the modified alumina comprises the following steps:

[0014] A1, blending alumina and boron trioxide, ball milling to obtain a composite;

[0015] A2, after uniformly dispersing the polylactic acid in tetrahydrofuran, adding the composite, mixing uniformly, concentrating, drying to obtain modified alumina.

[0016] As a further technical solution, the particle size of the alumina is 20-50μm;

[0017] The particle size of the boron trioxide is 100-500nm.

[0018] In the preparation process of the modified alumina, the nano boron trioxide has a relatively high specific surface area, which is easily adsorbed on the surface of the micron alumina through ball milling, thereby forming a composite of alumina and boron trioxide, and then through the modification treatment of polylactic acid, finally forming a modified alumina adsorbing boron trioxide and polylactic acid on the surface of alumina, which can more easily generate carbide dispersed phase around the alumina in situ in the later sintering process.

[0019] As a further technical solution, when ball milling, the ball milling speed is 200-300rpm, and the ball milling time is 2-3h;

[0020] In step A2, when mixing uniformly, in the form of stirring, the stirring speed is 300-400rpm, and the stirring time is 1-2h.

[0021] As a further technical solution, the sintering aid comprises one or more of Cr2O3, La2O3, Y2O3, and is preferably Cr2O3.

[0022] As a further technical solution, the dispersant comprises one or more of polyethylene glycol, tributyl phosphate, and triolein, and is preferably polyethylene glycol.

[0023] As a further technical solution, the binder comprises one or more of polyvinyl butyral, carboxymethyl cellulose, hydroxyethyl cellulose, and preferably polyvinyl butyral.

[0024] As a further technical solution, the solvent comprises one or both of ethanol and isopropyl alcohol, and preferably ethanol.

[0025] The present application provides a preparation method of a high-hardness alumina multilayer ceramic substrate, and the high-hardness alumina multilayer ceramic substrate prepared by the method comprises the following steps:

[0026] S1, blending and ball milling the components to obtain a casting slurry;

[0027] S2, deaerating, casting, drying, and punching the casting slurry to obtain a green ceramic sheet;

[0028] S3, punching, hole filling, printing, laminating, sintering, and cooling the green ceramic sheet to obtain the high-hardness alumina multilayer ceramic substrate.

[0029] As a further technical solution, in step S1, the ball milling speed is 500-600 rpm, for example, 500 rpm, 520 rpm, 550 rpm, 560 rpm, 580 rpm, or 600 rpm, and preferably 550 rpm, and the ball milling time is 1-2 h, for example, 1 h, 1.5 h, or 2 h, and preferably 2 h.

[0030] As a further technical solution, in step S3, the punching forms circular micropores with a diameter of 0.1-0.2 mm, for example, 0.1 mm, 0.15 mm, or 0.2 mm, and preferably 0.2 mm.

[0031] As a further technical solution, in step S3, the number of layers of the laminated sheet is 40-45, for example, 40 layers, 41 layers, 42 layers, 43 layers, 44 layers, or 45 layers, and preferably 40 layers.

[0032] As a further technical solution, in step S3, the sintering is performed in a nitrogen atmosphere at a sintering temperature of 1650-1750℃, for example, 1650℃, 1700℃, or 1750℃, and preferably 1700℃, and a sintering time of 15-30 min, for example, 15 min, 20 min, 25 min, or 30 min, and preferably 25 min.

[0033] The present application provides a preparation method of a high-hardness alumina multilayer ceramic substrate, and the high-hardness alumina multilayer ceramic substrate prepared by the method comprises the following steps:

[0034] B1, adding silicate into modified alumina, blending, then adding the remaining components, ball milling to obtain a casting slurry;

[0035] B2, deaerating, casting, drying, punching the casting slurry to obtain a green ceramic sheet;

[0036] B3, punching, hole filling, printing, laminating, sintering and cooling the green ceramic sheet to obtain the high-hardness alumina multilayer ceramic substrate.

[0037] As a further technical solution, in step B1, the addition of silicate is divided into first addition and second addition, in the first addition, 50% to 70% of the total mass of silicate is added, and in the second addition, the remaining silicate is added.

[0038] In the high-hardness alumina multilayer ceramic substrate, the silicate includes one or more of calcium silicate, magnesium silicate and aluminum silicate, and the calcium silicate is preferably used. When the calcium silicate is added, it is added twice, which can better interact with the modified alumina. In the high-temperature sintering process, the polylactic acid on the surface of the alumina is carbonized, and can interact with the decomposition product of the calcium silicate, further improving the fracture toughness of the alumina multilayer ceramic substrate. In addition, the decomposition product of calcium silicate, calcium oxide, can also inhibit the abnormal growth of alumina grains, thereby obtaining an alumina multilayer ceramic substrate with a relatively uniform internal structure.

[0039] In the high-hardness alumina multilayer ceramic substrate, when the calcium silicate is added, 50% to 70% of the total mass of the first addition of calcium silicate is added, and the remaining calcium silicate is added in the second addition, which can further improve the fracture toughness of the alumina multilayer ceramic substrate, and the fracture toughness can be improved to 12.8MPa·m 1 / 2 Above.

[0040] As a further technical solution, in the first addition and the second addition, ball milling is used for blending, and in the first addition and the second addition, the ball milling speed is independently 200 to 300 rpm, for example, it can be 200 rpm, 220 rpm, 250 rpm, 280 rpm, 300 rpm, and preferably 250 rpm, and the ball milling time is independently 30 to 40 minutes, for example, it can be 30 minutes, 35 minutes, 40 minutes, and preferably 30 minutes.

[0041] The working principle and beneficial effects of the present application are as follows:

[0042] The poly lactic acid is a degradable high molecular polymer, in the process of modifying the alumina, the poly lactic acid molecules can be adsorbed on the surface of the alumina, the dispersion degree of the alumina in the flow casting slurry is improved, then in the sintering process of preparing the alumina multilayer ceramic substrate, the poly lactic acid molecules are gradually decomposed and carbonized, and are used with the boron trioxide, the carbide dispersed phase is generated in situ in the alumina, thereby the elastic modulus of the multilayer ceramic substrate material is improved, when the internal material of the multilayer ceramic substrate is subjected to tensile stress, the generated carbide dispersed phase can prevent the transverse elastic shrinkage of the substrate, in order to achieve the transverse shrinkage coordination, the external tension needs to be increased, thereby more energy is consumed, and the fracture toughness of the alumina multilayer ceramic substrate is finally improved. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor also fall within the scope of protection of the present application.

[0044] In the following examples and comparative examples, the model of the poly lactic acid is FY601; the particle size of the calcium silicate is 10 μm; the model of the polyethylene glycol is PEG400; and the model of the polyvinyl butyral is TB-20.

[0045] Example 1

[0046] The preparation method of the modified alumina comprises the following steps:

[0047] A1, 100 parts of alumina (particle size is 20 μm) and 3 parts of boron trioxide (particle size is 100 nm) are blended, and ball milling is carried out at 200 rpm for 3 h to obtain a composite;

[0048] A2, 3 parts of poly lactic acid are uniformly dispersed in 150 parts of tetrahydrofuran, and then the above composite is added, stirring is carried out at 300 rpm for 2 h, concentration, drying are carried out, and modified alumina is obtained;

[0049] The preparation method of the high-hardness alumina multilayer ceramic substrate comprises the following steps:

[0050] S1, 100 parts of modified alumina, 10 parts of calcium silicate, 5 parts of Cr2O3, 2 parts of polyethylene glycol, 6 parts of polyvinyl butyral and 80 parts of ethanol are blended, and ball milling is carried out at a ball milling speed of 550 rpm for 2 h to obtain a flow casting slurry;

[0051] S2, the casting slurry is deaerated, cast, dried, punched to obtain green ceramic sheet;

[0052] S3, the green ceramic sheet is punched to form circular micropores with a diameter of 0.2mm, then filled and printed, 40 layers of green ceramic sheets are laminated and laminated, sintered at 1700℃ in nitrogen atmosphere for 25min, and cooled to obtain high-hardness alumina multilayer ceramic substrate.

[0053] Example 2

[0054] The preparation method of the modified alumina comprises the following steps:

[0055] A1, 100 parts of alumina (particle size 50μm) and 6 parts of boron trioxide (particle size 500nm) are blended, ball milled at 300rpm for 2h to obtain a composite;

[0056] A2, 6 parts of polylactic acid are uniformly dispersed in 150 parts of tetrahydrofuran, then the above composite is added, stirred at 400rpm for 1h, concentrated and dried to obtain modified alumina;

[0057] The preparation method of the high-hardness alumina multilayer ceramic substrate comprises the following steps:

[0058] S1, 100 parts of modified alumina, 15 parts of calcium silicate, 8 parts of Cr2O3, 5 parts of polyethylene glycol, 8 parts of polyvinyl butyral and 80 parts of ethanol are blended, ball milled at a speed of 550rpm for 2h to obtain a casting slurry;

[0059] S2, the casting slurry is deaerated, cast, dried, punched to obtain green ceramic sheet;

[0060] S3, the green ceramic sheet is punched to form circular micropores with a diameter of 0.2mm, then filled and printed, 40 layers of green ceramic sheets are laminated and laminated, sintered at 1700℃ in nitrogen atmosphere for 25min, and cooled to obtain high-hardness alumina multilayer ceramic substrate.

[0061] Example 3

[0062] The difference between this embodiment and Example 2 is only that in the preparation method of the modified alumina in this embodiment, 1 part of boron trioxide and 11 parts of polylactic acid are added.

[0063] Example 4

[0064] The difference between this embodiment and Example 2 is only that in the preparation method of the modified alumina in this embodiment, 4 parts of boron trioxide and 8 parts of polylactic acid are added.

[0065] Example 5

[0066] The difference between this embodiment and embodiment 2 is only that in the preparation method of the modified alumina in this embodiment, 2 parts of boron trioxide and 10 parts of polylactic acid are added.

[0067] Embodiment 6

[0068] The difference between this embodiment and embodiment 5 is only that the preparation method of the high-hardness alumina multilayer ceramic substrate in this embodiment is different, specifically:

[0069] B1, 15 parts of calcium silicate are added to 100 parts of modified alumina, and after ball milling at 250 rpm for 30 min, 8 parts of Cr2O3, 5 parts of polyethylene glycol, 8 parts of polyvinyl butyral and 80 parts of ethanol are added, and ball milling is carried out at a ball milling speed of 550 rpm for 2 h to obtain a flowable slurry;

[0070] B2, the flowable slurry is deaerated, flow-casted, dried, and punched to obtain a green ceramic sheet;

[0071] B3, the green ceramic sheet is punched to form circular micropores with a diameter of 0.2 mm, and then filled and printed, and 40 layers of green ceramic sheets are laminated and laminated, and then sintered at 1700°C in a nitrogen atmosphere for 25 min and cooled to obtain a high-hardness alumina multilayer ceramic substrate.

[0072] Embodiment 7

[0073] The difference between this embodiment and embodiment 6 is only that the preparation method of the high-hardness alumina multilayer ceramic substrate in this embodiment is different, specifically:

[0074] B1, 15 parts of calcium silicate are added to 100 parts of modified alumina, and after ball milling at 250 rpm for 30 min, 8 parts of Cr2O3, 5 parts of polyethylene glycol, 8 parts of polyvinyl butyral and 80 parts of ethanol are added, and ball milling is carried out at a ball milling speed of 550 rpm for 2 h to obtain a flowable slurry;

[0075] Embodiment 8

[0076] The difference between this embodiment and embodiment 6 is only that the preparation method of the high-hardness alumina multilayer ceramic substrate in this embodiment is different, specifically:

[0077] B1, 15 parts of calcium silicate are added to 100 parts of modified alumina, and after ball milling at 250 rpm for 30 min, 8 parts of Cr2O3, 5 parts of polyethylene glycol, 8 parts of polyvinyl butyral and 80 parts of ethanol are added, and ball milling is carried out at a ball milling speed of 550 rpm for 2 h to obtain a flowable slurry;

[0078] Comparative Example 1

[0079] The difference between the present comparative example and Example 2 is that, in the present comparative example, the polylactic acid is replaced by an equal amount of boron trioxide;

[0080] The preparation method of the modified alumina comprises the following steps: blending 100 parts of alumina (particle size of 50 μm) and 12 parts of boron trioxide (particle size of 100 nm), ball milling at 300 rpm for 2 h to obtain the modified alumina.

[0081] Comparative Example 2

[0082] The difference between the present comparative example and Example 2 is that, in the present comparative example, the boron trioxide is replaced by an equal amount of polylactic acid;

[0083] The preparation method of the modified alumina comprises the following steps: dispersing 12 parts of polylactic acid in 150 parts of tetrahydrofuran, adding 100 parts of alumina (particle size of 50 μm), stirring at 400 rpm for 1 h, concentrating, and drying to obtain the modified alumina.

[0084] Comparative Example 3

[0085] The difference between the present comparative example and Example 2 is that, in the present comparative example, the modified alumina is replaced by an equal amount of alumina.

[0086] Comparative Example 4

[0087] The difference between the present comparative example and Example 2 is that, in the present comparative example, the preparation method of the high-hardness alumina multilayer ceramic substrate is different from step S1, which is specifically as follows:

[0088] S1, blending 100 parts of alumina, 12 parts of boron carbide, 15 parts of calcium silicate, 8 parts of Cr2O3, 5 parts of polyethylene glycol, 8 parts of polyvinyl butyral, and 80 parts of ethanol, and ball milling at a ball milling speed of 550 rpm for 2 h to obtain a casting slurry;

[0089] S2, the casting slurry is deaerated, cast, dried, and punched to obtain a green ceramic sheet;

[0090] S3, the green ceramic sheet is punched to form circular micropores with a diameter of 0.2 mm, and then filled and printed, and 40 layers of green ceramic sheets are laminated and laminated, and sintered at 1700℃ in a nitrogen atmosphere for 25 min, and cooled to obtain a high-hardness alumina multilayer ceramic substrate.

[0091] Comparative Example 5

[0092] The difference between the present comparative example and Example 2 is that, in the present comparative example, no calcium silicate is added.

[0093] Experimental Example 1

[0094] The alumina multilayer ceramic substrate samples prepared from Examples 1-8 and Comparative Examples 1-5 were tested for fracture toughness according to the method in GB / T 23806-2009 "Fine Ceramic Fracture Toughness Test Method Single Edge Pre-cracked Beam (SEPB) Method", and the test results are shown in Table 1.

[0095] Table 1 Fracture toughness test results of Examples 1-8 and Comparative Examples 1-5

[0096]

[0097] Compared with Comparative Examples 1-5, the fracture toughness of the alumina multilayer ceramic substrate prepared from Examples 1-8 is improved, indicating that after the alumina is modified by polylactic acid and boron trioxide, and then combined with silicate and sintered at high temperature, the fracture toughness of the alumina multilayer ceramic substrate can be effectively improved, and the fracture toughness can be increased to 11.4 MPa·m 1 / 2 above.

[0098] Experimental Example 2

[0099] The Vickers hardness of the alumina multilayer ceramic substrates prepared from Examples 1-2 was tested according to the method specified in GB / T 16534-2009 "Fine Ceramic Room Temperature Hardness Test Method", and the test results are shown in Table 2.

[0100] Table 2 Vickers hardness test results of Examples 1-2

[0101]

[0102] As can be seen from Table 2, the Vickers hardness of the alumina multilayer ceramic substrates prepared from Examples 1-2 can reach more than 22.7 GPa, indicating that the alumina multilayer ceramic substrate prepared by the present application has high hardness and can meet the demand for hardness of the alumina multilayer ceramic substrate in actual application.

[0103] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high-hardness alumina multilayer ceramic substrate, characterized in that, The components include the following parts by weight: 100 parts modified alumina, 10-15 parts silicate, 5-8 parts sintering aid, 2-5 parts dispersant, 6-8 parts binder, and 80 parts solvent; The raw materials for the modified alumina include alumina and a modifier in a weight ratio of 50:3~6; The modifiers include polylactic acid and boron trioxide; The weight ratio of polylactic acid to boron trioxide is 2~5:1; The method for preparing the modified alumina includes the following steps: A1. Alumina and boron trioxide were mixed and ball-milled to obtain a composite. A2. After the polylactic acid is evenly dispersed in tetrahydrofuran, the composite is added, mixed evenly, concentrated, and dried to obtain modified alumina.

2. The high-hardness alumina multilayer ceramic substrate according to claim 1, characterized in that, The alumina has a particle size of 20~50μm; The boron trioxide has a particle size of 100~500nm.

3. The high-hardness alumina multilayer ceramic substrate according to claim 1, characterized in that, During the ball milling process, the milling speed is 200-300 rpm and the milling time is 2-3 hours. In step A2, the mixing is carried out by stirring at a speed of 300-400 rpm for 1-2 hours.

4. The high-hardness alumina multilayer ceramic substrate according to claim 1, characterized in that, The silicate includes one or more of calcium silicate, magnesium silicate, and aluminum silicate.

5. The high-hardness alumina multilayer ceramic substrate according to claim 1, characterized in that, The sintering aids include one or more of Cr2O3, La2O3, and Y2O3.

6. The high-hardness alumina multilayer ceramic substrate according to claim 1, characterized in that, The dispersant includes one or more of polyethylene glycol, tributyl phosphate, and trioleic acid glyceride.

7. The high-hardness alumina multilayer ceramic substrate according to claim 1, characterized in that, The adhesive includes one or more of polyvinyl butyral, carboxymethyl cellulose, and hydroxyethyl cellulose.

8. The high-hardness alumina multilayer ceramic substrate according to claim 1, characterized in that, The solvent includes one or both of ethanol and isopropanol.

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