Low dielectric constant multilayer ceramic substrate and preparation method thereof

Abstract

The present invention relates to the field of ceramic substrate technology and provides a low-dielectric-constant multilayer ceramic substrate and a method for preparing the same. The low-dielectric-constant multilayer ceramic substrate comprises the following components by weight: 100 parts aluminum oxide, 4-8 parts sintering aid, 8-16 parts silicate, 3-6 parts copper oxide, 3-5 parts dispersant, 6-12 parts binder, and 70 parts solvent; the silicate comprises magnesium aluminum silicate and zirconium silicate in a weight ratio of 1.5-9:1. This technical solution overcomes the poor flexural strength problem of 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 low dielectric constant multilayer ceramic substrate and a preparation method thereof. Background Art

[0002] As electronic devices evolve toward higher frequencies and greater integration, multilayer ceramic substrates, as carriers of key electronic components, face increasingly stringent performance requirements. Flexural strength is a key indicator of ceramic substrate reliability, directly impacting the substrate's resistance to fracture and long-term stability during processing, assembly, and use. Insufficient flexural strength can lead to substrate cracking, delamination, and even functional failure, particularly in high-temperature, high-humidity, or mechanically stressed environments, severely impacting the lifespan and reliability of electronic devices.

[0003] Existing technologies typically enhance the bonding between ceramic powders by adding organic binders or other additives. These binders can form a network structure during the green stage, improving the green body strength to a certain extent. However, they decompose and volatilize during high-temperature sintering, creating pores within the substrate and reducing density, which limits the improvement in the ceramic substrate's flexural strength. Furthermore, excessive use of binders can introduce impurities, affecting the overall performance of multilayer ceramic substrates.

[0004] Therefore, developing a multilayer ceramic substrate with good bending strength is of great significance for improving the service life of the multilayer ceramic substrate and expanding its application range. Summary of the Invention

[0005] The present invention provides a low dielectric constant multilayer ceramic substrate and a preparation method thereof, which solves the problem of poor bending strength of the multilayer ceramic substrate in the related art.

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

[0007] The present invention provides a low dielectric constant multilayer ceramic substrate, comprising the following components in parts by weight:

[0008] 100 parts of aluminum oxide, 4-8 parts of sintering aid, 8-16 parts of silicate, 3-6 parts of copper oxide, 3-5 parts of dispersant, 6-12 parts of binder, 70 parts of solvent;

[0009] The silicate comprises magnesium aluminum silicate and zirconium silicate in a weight ratio of 1.5 to 9:1.

[0010] In the present invention, the sintering aid of the low dielectric constant multilayer ceramic substrate can reduce the sintering temperature of the low dielectric constant multilayer ceramic substrate green tape, forming a low melting point eutectic phase or solid solution, thereby achieving densification of the low dielectric constant multilayer ceramic substrate at a lower temperature. The sintering aid can be any one or more conventional sintering aids in the field, for example, it can be one or more of Y2O3, CaF2, and La2O3, preferably Y2O3.

[0011] In the present invention, in the low dielectric constant multilayer ceramic substrate, the addition of the dispersant can be adsorbed on the surface of the inorganic powder particles, and through steric hindrance and electrostatic repulsion, the inorganic powder particles can be separated from each other, thereby reducing the agglomeration of the inorganic powder particles, forming a uniform and stable casting slurry, and improving the stability of the green ceramic sheet. The dispersant can be any one or more conventional dispersants in the art, for example, it can be one or both of tributyl phosphate and polyethylene glycol, preferably polyethylene glycol.

[0012] In the present invention, in the low dielectric constant multilayer ceramic substrate, the binder can bind the inorganic powder particles in the low dielectric constant multilayer ceramic substrate together to form a green ceramic sheet that is not easily deformed or cracked. In addition, most importantly, the binder connects the inorganic powder particles to form a network structure, increases the bonding force between the particles, thereby improving the overall strength of the green ceramic sheet, and thus giving the low dielectric constant multilayer ceramic substrate basic bending strength. The binder can be any one or more conventional binders in the art, for example, one or both of hydroxypropyl methylcellulose and polyvinyl butyral, preferably polyvinyl butyral.

[0013] As a further technical solution, the weight ratio of the magnesium aluminum silicate to the zirconium silicate is 3 to 5:1.

[0014] In the present invention, the low-dielectric-constant multilayer ceramic substrate uses alumina as its matrix. Alumina itself has good chemical stability and can provide basic mechanical strength and structural support for the low-dielectric-constant multilayer ceramic substrate. Under the combined action of sintering aids, silicates, copper oxide, dispersants, binders, and solvents, a low-dielectric-constant multilayer ceramic substrate with a dense and stable internal structure and good flexural strength can be formed.

[0015] In the present invention, the silicate includes magnesium aluminum silicate and zirconium silicate, and the weight ratio of the two is 1.5~9:1, for example, it can be 1.5:1, 2:1, 3:1, 4:1, 5:1, 8:1, 9:1, preferably 1.5:1, 3:1, 5:1, 9:1, and more preferably 3:1, 5:1. In the present invention, when the weight ratio of magnesium aluminum silicate to zirconium silicate is 3~5:1, the flexural strength of the low dielectric constant multilayer ceramic substrate can be further improved, and the flexural strength can reach 484~489 MPa. When the weight ratio of magnesium aluminum silicate to zirconium silicate is outside the range of 3~5:1, the effect of improving the flexural strength of the low dielectric constant multilayer ceramic substrate is poor.

[0016] As a further technical solution, the silicate is a boron composite silicate, and the raw materials of the boron composite silicate include silicate, a boron source, and cage-type polysilsesquioxane.

[0017] As a further technical solution, the boron source includes an organic boron source and an inorganic boron source;

[0018] The organic boron source includes phenylboronic acid compounds;

[0019] The inorganic boron source includes one or more of magnesium metaborate, lithium metaborate, and sodium metaborate.

[0020] In the present invention, a composite treatment of silicate with a boron source and a cage-type polysilsesquioxane can reduce the dielectric constant of a multilayer ceramic substrate without affecting its flexural strength. This is presumably due to the following: the introduction of a boron source into the silicate forms boron-oxygen bonds, which improve the stability of the silicate's crystal structure to a certain extent, thereby reducing the silicate's polarization under the action of an electric field. Simultaneously, the introduction of the cage-type polysilsesquioxane enhances the interfacial bonding between the silicate and the various components of the multilayer ceramic substrate, thereby reducing the dielectric constant of the multilayer ceramic substrate without affecting its flexural strength.

[0021] In the present invention, the boron source is an organic boron source and an inorganic boron source. By using the organic boron source and the inorganic boron source in combination, the silicate is first pretreated with the organic boron source, which can improve the subsequent degree of binding with the inorganic boron source. At the same time, the presence of the organic boron source can promote, to a certain extent, better binding of the cage-type polysilsesquioxane and the silicate, thereby contributing to the successful preparation of boron composite silicate.

[0022] In the present invention, the phenylboronic acid compound includes one or more of phenylboronic acid, p-methylphenylboronic acid, and p-hydroxymethylphenylboronic acid, preferably p-hydroxymethylphenylboronic acid.

[0023] As a further technical solution, in the raw material of boron composite silicate, the weight ratio of the silicate, cage-type polysilsesquioxane, and boron source is 30:4:1~4, for example, it can be 30:4:1, 30:4:2, 30:4:3, 30:4:3.2, 30:4:3.5, 30:4:4, preferably 30:4:1, 30:4:2, 30:4:3.2, 30:4:4, and more preferably 30:4:2, 30:4:3.2.

[0024] In the present invention, when the weight ratio of silicate, cage-type polysilsesquioxane, and boron source is 30:4:1-4, the dielectric constant of the multilayer ceramic substrate can be reduced to below 6.3. When the weight ratio of silicate, cage-type polysilsesquioxane, and boron source is 30:4:2-3.2, the dielectric constant of the multilayer ceramic substrate can be further reduced to 5.3-5.6.

[0025] As a further technical solution, the weight ratio of the organic boron source to the inorganic boron source is 1:1~3, for example, it can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, preferably 1:1, 1:3, and more preferably 1:3.

[0026] As a further technical solution, the preparation method of the boron composite silicate comprises the following steps:

[0027] A1. Dispersing the organic boron source in anhydrous ethanol, adding the silicate, mixing uniformly, concentrating, and drying to obtain a silicate mixture A;

[0028] A2, blending the silicate mixture A, the inorganic boron source and water, ball milling, and drying to obtain a silicate mixture B;

[0029] A3. Dispersing the cage-type polysilsesquioxane in dimethylformamide, adding the silicate mixture B, mixing evenly, concentrating, drying, and calcining to obtain boron composite silicate.

[0030] As a further technical solution, in step A1, the amount of anhydrous ethanol added is 4 to 5 times the weight of the organic boron source, for example, it can be 4 times, 4.2 times, 4.4 times, 4.5 times, 4.6 times, 4.8 times, 5 times, preferably 4.4 times.

[0031] As a further technical solution, in step A2, the amount of water added is 3 to 4 times the weight of the inorganic boron source, for example, it can be 3 times, 3.1 times, 3.2 times, 3.5 times, 3.8 times, 4 times, preferably 4 times.

[0032] As a further technical solution, in step A2, during the ball milling, the ball milling speed is 250-330 rpm, and the ball milling time is 3-4 h.

[0033] As a further technical solution, in step A3, the amount of dimethylformamide added is 5 to 7 times the weight of the cage-type polysilsesquioxane, for example, 5 times, 5.5 times, 5.8 times, 6 times, 6.5 times, 7 times, preferably 6 times.

[0034] As a further technical solution, in step A3, when the mixing is uniform, the stirring is carried out at a speed of 250-330 rpm and a stirring time of 30-50 min.

[0035] As a further technical solution, in step A3, during the calcination, the temperature is 350~370°C, for example, it can be 350°C, 360°C, 365°C, 370°C, preferably 365°C, and the time is 40~60 min, for example, it can be 40 min, 45 min, 50 min, 55 min, 60 min, preferably 50 min.

[0036] As a further technical solution, the solvent includes one or both of ethanol and acetone, preferably ethanol.

[0037] The present invention provides a method for preparing a low dielectric constant multilayer ceramic substrate, which is used to prepare the low dielectric constant multilayer ceramic substrate, comprising the following steps:

[0038] S1. Blending the remaining components except the binder, dispersing them uniformly, adding the binder, and mixing them uniformly to obtain a casting slurry;

[0039] S2, degassing, casting, drying, and punching the casting slurry to obtain a green porcelain tape;

[0040] S3, punching, filling, printing, laminating, sintering, and cooling the green ceramic tape to obtain the low dielectric constant multilayer ceramic substrate.

[0041] As a further technical solution, in step S3, when laminating, the number of layers is 30 to 45, for example, it can be 30, 32, 35, 40, 42, 45, preferably 30, 40, 45, and more preferably 40.

[0042] As a further technical solution, in step S3, during the sintering, the sintering atmosphere is air, and the sintering temperature is 1100~1250℃, for example, it can be 1100℃, 1120℃, 1150℃, 1165℃, 1170℃, 1180℃, 1200℃, 1250℃, preferably 1100℃, 1250℃, 1180℃, and the sintering time is 20~40min, for example, it can be 20min, 30min, 40min.

[0043] As a further technical solution, in step S3, the printed material is tungsten paste, and the printing thickness of the tungsten paste is 16~18μm, for example, it can be 16μm, 16.5μm, 17μm, 18μm, preferably 16μm, 17μm, 18μm, and more preferably 17μm.

[0044] The working principle and beneficial effects of the present invention are:

[0045] 1. In the present invention, silicates are introduced into a low-dielectric-constant multilayer ceramic substrate. The silicates include magnesium aluminum silicate and zirconium silicate. The combined use of magnesium aluminum silicate and zirconium silicate effectively improves the flexural strength of the low-dielectric-constant multilayer ceramic substrate. Existing technologies often utilize organic bonding agents in ceramic substrates to improve the bonding between ceramic powders to achieve the purpose of improving the flexural strength of multilayer ceramic substrates. However, because organic bonding agents decompose at high temperatures, they reduce the internal density of the ceramic substrate, limiting the improvement in the flexural strength of low-dielectric-constant multilayer ceramic substrates. The present invention not only pays attention to the inherent reinforcing effect of the binder component in the ceramic substrate, but also pays attention to the influence of the complexity of the coordination of the inorganic components within the ceramic substrate on the flexural strength of the ceramic substrate. Two silicates, magnesium aluminum silicate and zirconium silicate, are introduced into the low dielectric constant multilayer ceramic substrate. Through the combined use of magnesium aluminum silicate and zirconium silicate, while playing a supporting role together with alumina, the interface bonding with the alumina matrix during the sintering process can be enhanced, thereby hindering the crack propagation of the ceramic substrate during the sintering process, thereby improving the flexural strength of the low dielectric constant multilayer ceramic substrate.

[0046] 2. In the present invention, the content ratio of magnesium aluminum silicate and zirconium silicate is reasonably controlled to be 1.5~9:1, which can enable magnesium aluminum silicate and zirconium silicate to play a good synergistic role, so that the flexural strength of the low dielectric constant multilayer ceramic substrate is increased to above 468MPa, and it has good ability to resist external stress. DETAILED DESCRIPTION

[0047] 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.

[0048] In the following examples and comparative examples, the model of polyvinyl butyral is TB-20; the model of polyethylene glycol is PEG400; the particle size of magnesium aluminum silicate is 30 μm; the particle size of zirconium silicate is 45 μm; and the viscosity of cage-type polysilsesquioxane is 2200 cps.

[0049] Example 1

[0050] A method for preparing a low dielectric constant multilayer ceramic substrate comprises the following steps:

[0051] S1. Blend 100 parts of aluminum oxide, 4 parts of Y2O3, 4.8 parts of magnesium aluminum silicate, 3.2 parts of zirconium silicate, 3 parts of copper oxide, 3 parts of polyethylene glycol, and 70 parts of ethanol, disperse them uniformly, add 6 parts of polyvinyl butyral, mix well, and obtain a casting slurry;

[0052] S2, degassing, casting, drying, and punching the tape slurry to obtain a green porcelain tape;

[0053] S3. Punch and fill the green porcelain tape, print a tungsten paste material with a thickness of 17 μm, stack and laminate 30 layers of green porcelain tape, sinter at 1100° C. in an air atmosphere for 40 minutes, and cool to obtain a low dielectric constant multilayer ceramic substrate.

[0054] Example 2

[0055] A method for preparing a low dielectric constant multilayer ceramic substrate comprises the following steps:

[0056] S1, 100 parts of aluminum oxide, 6 parts of Y2O3, 7.2 parts of magnesium aluminum silicate, 4.8 parts of zirconium silicate, 5 parts of copper oxide, 4 parts of polyethylene glycol and 70 parts of ethanol were blended and evenly dispersed, and then 8 parts of polyvinyl butyral were added and mixed evenly to obtain a casting slurry;

[0057] S2, degassing, casting, drying, and punching the tape slurry to obtain a green porcelain tape;

[0058] S3. Punch and fill the green porcelain tape, print a tungsten paste material with a thickness of 17 μm, stack and laminate 40 layers of the green porcelain tape, sinter at 1180° C. in an air atmosphere for 30 minutes, and cool to obtain a low dielectric constant multilayer ceramic substrate.

[0059] Example 3

[0060] A method for preparing a low dielectric constant multilayer ceramic substrate comprises the following steps:

[0061] S1. Blend 100 parts of aluminum oxide, 8 parts of Y2O3, 14.4 parts of magnesium aluminum silicate, 1.6 parts of zirconium silicate, 6 parts of copper oxide, 5 parts of polyethylene glycol, and 70 parts of ethanol, disperse them uniformly, add 12 parts of polyvinyl butyral, mix well, and obtain a casting slurry;

[0062] S2, degassing, casting, drying, and punching the tape slurry to obtain a green porcelain tape;

[0063] S3. Punch and fill the green porcelain tape, print a tungsten paste material with a thickness of 17 μm, stack and laminate 45 layers of the green porcelain tape, sinter at 1250° C. in an air atmosphere for 20 minutes, and cool to obtain a low dielectric constant multilayer ceramic substrate.

[0064] Example 4

[0065] The only difference between this embodiment and embodiment 2 is that, in this embodiment, 10.8 parts of magnesium aluminum silicate and 1.2 parts of zirconium silicate are added.

[0066] Example 5

[0067] The only difference between this embodiment and embodiment 2 is that, in this embodiment, 9 parts of magnesium aluminum silicate and 3 parts of zirconium silicate are added.

[0068] Example 6

[0069] The only difference between this embodiment and embodiment 2 is that, in this embodiment, 10 parts of magnesium aluminum silicate and 2 parts of zirconium silicate are added.

[0070] Example 7

[0071] The only difference between this embodiment and embodiment 6 is that, in this embodiment, the silicate is a boron composite silicate, and the preparation method of the boron composite silicate includes the following steps:

[0072] A1. Disperse 0.5 parts of p-hydroxymethylphenylboric acid in 2.2 parts of anhydrous ethanol, add 25 parts of magnesium aluminum silicate and 5 parts of zirconium silicate, mix well, concentrate, and dry to obtain a silicate mixture A;

[0073] A2, blending the silicate mixture A, 0.5 parts of magnesium metaborate and 2 parts of water, ball milling at a ball milling speed of 300 rpm for 3.5 hours, and drying to obtain a silicate mixture B;

[0074] A3, dispersing 4 parts of cage-type polysilsesquioxane in 24 parts of dimethylformamide, adding silicate mixture B, mixing evenly, concentrating, drying, and calcining at 365° C. for 50 min to obtain boron composite silicate;

[0075] A method for preparing a low dielectric constant multilayer ceramic substrate comprises the following steps:

[0076] S1. Blend 100 parts of aluminum oxide, 6 parts of Y2O3, 12 parts of boron composite silicate, 5 parts of copper oxide, 4 parts of polyethylene glycol, and 70 parts of ethanol, disperse them uniformly, then add 8 parts of polyvinyl butyral and mix them uniformly to obtain a casting slurry;

[0077] S2, degassing, casting, drying, and punching the tape slurry to obtain a green porcelain tape;

[0078] S3. Punch and fill the green porcelain tape, print a tungsten paste material with a thickness of 17 μm, stack and laminate 40 layers of the green porcelain tape, sinter at 1180° C. in an air atmosphere for 30 minutes, and cool to obtain a low dielectric constant multilayer ceramic substrate.

[0079] Example 8

[0080] The only difference between this embodiment and embodiment 7 is that, in this embodiment, the preparation method of boron composite silicate includes the following steps:

[0081] A1. Disperse 0.25 parts of p-hydroxymethylphenylboric acid in 1.1 parts of anhydrous ethanol, add 25 parts of magnesium aluminum silicate and 5 parts of zirconium silicate, mix well, concentrate, and dry to obtain a silicate mixture A;

[0082] A2. Blend the silicate mixture A, 0.75 parts of magnesium metaborate, and 3 parts of water, ball mill at 300 rpm for 3.5 hours, and dry to obtain a silicate mixture B;

[0083] A3. Disperse 4 parts of cage-type polysilsesquioxane in 24 parts of dimethylformamide, add silicate mixture B, mix well, concentrate, dry, and calcine at 365° C. for 50 min to obtain boron composite silicate.

[0084] Example 9

[0085] The only difference between this embodiment and embodiment 7 is that, in this embodiment, the preparation method of boron composite silicate includes the following steps:

[0086] A1. Disperse 1 part of p-hydroxymethylphenylboric acid in 4.4 parts of anhydrous ethanol, add 25 parts of magnesium aluminum silicate and 5 parts of zirconium silicate, mix well, concentrate, and dry to obtain a silicate mixture A;

[0087] A2, blending the silicate mixture A, 3 parts of magnesium metaborate and 12 parts of water, ball milling at a ball milling speed of 300 rpm for 3.5 hours, and drying to obtain a silicate mixture B;

[0088] A3. Disperse 4 parts of cage-type polysilsesquioxane in 24 parts of dimethylformamide, add silicate mixture B, mix well, concentrate, dry, and calcine at 365° C. for 50 min to obtain boron composite silicate.

[0089] Example 10

[0090] The only difference between this embodiment and embodiment 7 is that, in this embodiment, the preparation method of boron composite silicate includes the following steps:

[0091] A1. Disperse 0.5 parts of p-hydroxymethylphenylboric acid in 2.2 parts of anhydrous ethanol, add 25 parts of magnesium aluminum silicate and 5 parts of zirconium silicate, mix well, concentrate, and dry to obtain a silicate mixture A;

[0092] A2, blending the silicate mixture A, 1.5 parts of magnesium metaborate and 6 parts of water, ball milling at a ball milling speed of 300 rpm for 3.5 hours, and drying to obtain a silicate mixture B;

[0093] A3. Disperse 4 parts of cage-type polysilsesquioxane in 24 parts of dimethylformamide, add silicate mixture B, mix well, concentrate, dry, and calcine at 365° C. for 50 min to obtain boron composite silicate.

[0094] Example 11

[0095] The only difference between this embodiment and embodiment 7 is that, in this embodiment, the preparation method of boron composite silicate includes the following steps:

[0096] A1. Disperse 0.8 parts of p-hydroxymethylphenylboric acid in 3.52 parts of anhydrous ethanol, add 25 parts of magnesium aluminum silicate and 5 parts of zirconium silicate, mix well, concentrate, and dry to obtain a silicate mixture A;

[0097] A2, blending the silicate mixture A, 2.4 parts of magnesium metaborate and 9.6 parts of water, ball milling at a ball milling speed of 300 rpm for 3.5 hours, and drying to obtain a silicate mixture B;

[0098] A3. Disperse 4 parts of cage-type polysilsesquioxane in 24 parts of dimethylformamide, add silicate mixture B, mix well, concentrate, dry, and calcine at 365° C. for 50 min to obtain boron composite silicate.

[0099] Comparative Example 1

[0100] The only difference between this comparative example and Example 2 is that in this comparative example, magnesium aluminum silicate is replaced by an equal amount of zirconium silicate.

[0101] Comparative Example 2

[0102] The only difference between this comparative example and Example 2 is that in this comparative example, zirconium silicate is replaced by an equal amount of magnesium aluminum silicate.

[0103] Comparative Example 3

[0104] The only difference between this comparative example and Example 2 is that in this comparative example, magnesium aluminum silicate and zirconium silicate are not added.

[0105] Experimental Example 1

[0106] The low dielectric constant multilayer ceramic substrates prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were tested for flexural strength according to the test method specified in GB / T 6569-2006 "Test Method for Flexural Strength of Fine Ceramics". The test method adopted three-point bending. The test results are shown in Table 1:

[0107] Table 1 Bending strength test results of Examples 1 to 6 and Comparative Examples 1 to 3

[0108]

[0109] Compared with Comparative Examples 1 to 3, the flexural strength of the low dielectric constant multilayer ceramic substrates prepared in Examples 1 to 6 is improved, indicating that when the silicate includes magnesium aluminum silicate and zirconium silicate, magnesium aluminum silicate and zirconium silicate have a synergistic effect, which can improve the flexural strength of the low dielectric constant multilayer ceramic substrate, and the flexural strength can be increased to above 468 MPa.

[0110] Experimental Example 2

[0111] The low dielectric constant multilayer ceramic substrates prepared in Examples 6 to 11 were subjected to dielectric constant testing according to the method in GB / T 5594.4-2015 "Test methods for properties of structural ceramic materials for electronic components - Part 4: Test method for dielectric constant and dielectric loss tangent". The test conditions were 10 GHz and 20°C. The test results are shown in Table 2:

[0112] Table 2 Dielectric constant test results of Examples 6 to 11

[0113]

[0114] Compared with Example 6, the dielectric constant of the multilayer ceramic substrates prepared in Examples 7 to 11 is reduced, indicating that the boron composite silicate formed after calcination by composite treatment of silicate with a boron source and a cage-type polysilsesquioxane can reduce the dielectric constant of the multilayer ceramic substrate to below 6.3.

[0115] 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 low dielectric constant multilayer ceramic substrate, characterized in that: The composition comprises the following components in parts by weight: 100 parts of aluminum oxide, 4-8 parts of sintering aid, 8-16 parts of silicate, 3-6 parts of copper oxide, 3-5 parts of dispersant, 6-12 parts of binder, 70 parts of solvent; The silicate comprises magnesium aluminum silicate and zirconium silicate in a weight ratio of 1.5 to 9:1; The silicate is a boron composite silicate, and the raw materials of the boron composite silicate include silicate, a boron source, and cage-type polysilsesquioxane.

2. The low dielectric constant multilayer ceramic substrate according to claim 1, wherein: The weight ratio of the magnesium aluminum silicate to the zirconium silicate is 3 to 5:

1.

3. The low dielectric constant multilayer ceramic substrate according to claim 1, wherein: The boron source includes an organic boron source and an inorganic boron source; The organic boron source includes phenylboronic acid compounds; The inorganic boron source includes one or more of magnesium metaborate, lithium metaborate, and sodium metaborate.

4. The low dielectric constant multilayer ceramic substrate according to claim 1, wherein: In the raw materials of boron composite silicate, the weight ratio of the silicate, cage-type polysilsesquioxane and boron source is 30:4:1-4.

5. The low dielectric constant multilayer ceramic substrate according to claim 3, wherein: The weight ratio of the organic boron source to the inorganic boron source is 1:1-3.

6. The low dielectric constant multilayer ceramic substrate according to claim 3, wherein: The preparation method of the boron composite silicate comprises the following steps: A1. Dispersing the organic boron source in anhydrous ethanol, adding the silicate, mixing uniformly, concentrating, and drying to obtain a silicate mixture A; A2, blending the silicate mixture A, the inorganic boron source and water, ball milling, and drying to obtain a silicate mixture B; A3. Dispersing the cage-type polysilsesquioxane in dimethylformamide, adding the silicate mixture B, mixing evenly, concentrating, drying, and calcining to obtain boron composite silicate.

7. The low dielectric constant multilayer ceramic substrate according to claim 1, wherein: The sintering aid includes one or more of Y2O3, CaF2, and La2O3; The dispersant includes one or both of tributyl phosphate and polyethylene glycol; The binder includes one or two of hydroxypropyl methylcellulose and polyvinyl butyral; The solvent includes one or both of ethanol and acetone.

8. A method for preparing a low dielectric constant multilayer ceramic substrate, for preparing the low dielectric constant multilayer ceramic substrate according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Blending the remaining components except the binder, dispersing them uniformly, adding the binder, and mixing them uniformly to obtain a casting slurry; S2, degassing, casting, drying, and punching the casting slurry to obtain a green porcelain tape; S3, punching, filling, printing, laminating, sintering, and cooling the green ceramic tape to obtain the low dielectric constant multilayer ceramic substrate.

9. The method for preparing a low dielectric constant multilayer ceramic substrate according to claim 8, wherein: In step S3, when laminating, the number of layers is 30 to 45.

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