Low warpage multilayer ceramic substrate and method of making the same

Abstract

The application relates to the technical field of ceramic substrates, and discloses a low-warp multilayer ceramic substrate and a preparation method thereof, wherein the low-warp multilayer ceramic substrate comprises the following raw materials in parts by weight: 90-110 parts of alumina, 3-4 parts of a dispersing agent, 4-6 parts of a plasticizer, 10-12 parts of a binder, 3-4 parts of a sintering aid, 70-80 parts of a solvent and 6-9 parts of a functional aid; the functional aid comprises modified SiC particles; the modified SiC particles are obtained by successively coating SiC particles with SiO2 and Al2O3. The above technical scheme solves the problem of insufficient mechanical properties of the low-warp multilayer ceramic substrate in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic substrate, in particular, relates to a low warpage multilayer ceramic substrate and a preparation method thereof. BACKGROUND

[0002] Ceramic materials are widely used in high-end fields such as machinery, chemistry, energy, aerospace, biomedicine due to their excellent physical and chemical properties. In the packaging of power devices, ceramic substrate is a commonly used material, among which, using alumina ceramic substrate as packaging material can provide a series of excellent performances such as good bottom support, high insulation performance, low dielectric loss and dielectric constant, and high thermal conductivity. However, the current low warpage ceramic substrate has the problem of poor mechanical properties, because in order to realize low warpage, the existing process usually adjusts the ceramic composition or microstructure to reduce the thermal expansion coefficient of the substrate, but these adjustments often lead to the decrease of the density of the ceramic, resulting in problems such as increased porosity and uneven grain growth during sintering. As a stress concentration point, the porosity will significantly reduce the bending strength and fracture toughness of the substrate. Therefore, there is an urgent need for a low warpage multilayer ceramic substrate with high toughness and high strength. SUMMARY

[0003] The present application provides a low warpage multilayer ceramic substrate and a preparation method thereof, which solves the problem of insufficient mechanical properties of the low warpage multilayer ceramic substrate in the related art.

[0004] The technical scheme of the present application is as follows:

[0005] The present application provides a low warpage multilayer ceramic substrate, which comprises the following raw materials by weight: 90-110 parts of alumina, 3-4 parts of dispersant, 4-6 parts of plasticizer, 10-12 parts of binder, 3-4 parts of sintering aid, 70-80 parts of solvent and 6-9 parts of functional aid.

[0006] The functional aid comprises modified SiC particles.

[0007] The modified SiC particles are obtained by coating SiC particles with SiO2 and Al2O3 in sequence.

[0008] As a further technical scheme, the preparation method of the modified SiC particles comprises the following steps:

[0009] A1, dispersing SiC powder in ethanol, adding ammonia water to adjust the pH to 7.5-9.5, adding tetraethyl orthosilicate dropwise, stirring, centrifuging, alcohol washing, drying to obtain SiO2 coated SiC particles;

[0010] A2, dispersing the SiO2-coated SiC particles in water, adding a buffer solution, then adding an Al(NO3)3 solution, ultrasonicating, stirring, then adding ammonia water to adjust the pH to 6.5-7.5, incubating, alcohol washing, and drying to obtain modified SiC particles.

[0011] As a further technical solution, the buffer solution comprises an acetic acid-sodium acetate solution.

[0012] As a further technical solution, in step A1, the temperature of the stirring is 40-50°C, and the time is 4-4.5 h.

[0013] In step A2, the temperature of the incubation is 70-80°C, and the time is 30-40 min.

[0014] As a further technical solution, the mass-volume ratio of the SiC powder and ethanol is 1 g:300 mL.

[0015] As a further technical solution, the mass-volume ratio of the SiC powder and tetraethyl orthosilicate is 1 g:3-5 mL.

[0016] The concentration of the Al(NO3)3 solution is 0.1-0.2 mol / L.

[0017] As a further technical solution, the mass-volume ratio of the SiO2-coated SiC particles and the Al(NO3)3 solution is 1 g:100-110 mL.

[0018] Preferably, the mass-volume ratio of the SiO2-coated SiC particles and water is 1 g:100 mL.

[0019] As a further technical solution, the mass-volume ratio of the SiO2-coated SiC particles and the buffer solution is 1 g:8-10 mL.

[0020] Preferably, the mass-volume ratio of the SiO2-coated SiC particles and the buffer solution is 1 g:10 mL.

[0021] As a further technical solution, in steps A1 and A2, the mass fraction of the ammonia water is independently 25wt%-28wt%.

[0022] Preferably, in steps A1 and A2, the mass fraction of the ammonia water is independently 26wt%.

[0023] As a further technical solution, the dropping speed of the tetraethyl orthosilicate is 0.15-0.2 mL / min.

[0024] In step A2, the dropping speed of the Al(NO3)3 solution is 3-3.5 mL / min.

[0025] As a further technical solution, the concentration of the Al(NO3)3 solution is 0.1-0.2 mol / L.

[0026] Preferably, the concentration of the Al(NO3)3 solution is 0.15 mol / L.

[0027] As a further technical solution, the functional additive further comprises zirconium oxide whiskers.

[0028] In the low-warp multilayer ceramic substrate, the modified SiC particles and the zirconium oxide whiskers are used in combination, and the mechanical properties of the ceramic substrate are further improved through the synergistic effect of the particles and the whiskers.

[0029] As a further technical solution, the mass ratio of the modified SiC particles to the zirconium oxide whiskers is 1:1-2.

[0030] In the present application, by adjusting the mass ratio of the modified SiC particles to the zirconium oxide whiskers, and when the mass ratio of the modified SiC particles to the zirconium oxide whiskers is 1:1-2, the mechanical properties of the ceramic substrate can be further improved.

[0031] As a further technical solution, the sintering aid comprises one or both of magnesium oxide and calcium oxide.

[0032] The solvent comprises one or both of ethanol and isopropanol.

[0033] As a further technical solution, the dispersant comprises cetyltrimethylammonium bromide.

[0034] In the low-warp multilayer ceramic substrate, cetyltrimethylammonium bromide is added as a dispersant, and cetyltrimethylammonium bromide is a cationic surfactant that can adsorb particles in the slurry, making them positively charged, and the positive charge will generate electrostatic repulsion, thereby preventing particle agglomeration and making the particles more uniformly dispersed, thereby improving the mechanical properties of the ceramic substrate.

[0035] The plasticizer comprises one or both of polyethylene glycol and glycerol.

[0036] In the low warping multilayer ceramic substrate, polyethylene glycol and glycerol are added as plasticizers, the polyethylene glycol molecular chain contains a large number of ether bonds, such groups can form hydrogen bonds with active groups such as hydroxyl groups on the surface of ceramic particles, and at the same time, the linear long chain structure can fill the gap between the ceramic particles, weaken the interaction force between the particles, and finally improve the plasticity of the ceramic body; the glycerol molecule contains three hydroxyl groups, which can form a hydration film on the surface of the ceramic particles, can significantly reduce the frictional resistance between the particles, reduce the resistance of the relative movement of the particles, and can enhance the bonding strength between the particles, so that the prepared ceramic substrate has good mechanical properties.

[0037] As a further technical solution, the binder comprises polyvinyl butyral.

[0038] In the low warping multilayer ceramic substrate, polyethylene glycol and glycerol are added as plasticizers, the polyethylene glycol molecular chain contains a large number of ether bonds, such groups can form hydrogen bonds with active groups such as hydroxyl groups on the surface of ceramic particles, and at the same time, the linear long chain structure can fill the gap between the ceramic particles, weaken the interaction force between the particles, and finally improve the plasticity of the ceramic body; the glycerol molecule contains three hydroxyl groups, which can form a hydration film on the surface of the ceramic particles, can significantly reduce the frictional resistance between the particles, reduce the resistance of the relative movement of the particles, and can enhance the bonding strength between the particles, so that the prepared ceramic substrate has good mechanical properties.

[0039] The application further provides a preparation method of the low warping multilayer ceramic substrate.

[0040] S1, mixing raw materials, casting, drying, and obtaining green ceramic sheets;

[0041] S2, punching and filling the green ceramic sheets, performing surface printing, laminating and pressing, up and down conduction, cutting, sintering, and cooling, and obtaining the low warping multilayer ceramic substrate.

[0042] The working principle and beneficial effects of the application are as follows:

[0043] In the application, the SiC particles coated with silicon dioxide and aluminum oxide in sequence are used, so that the mechanical properties of the prepared multilayer ceramic substrate are enhanced. On the one hand, the dispersibility of the SiC particles in the slurry is improved by coating the SiC particles with silicon dioxide, so that the mechanical properties of the prepared ceramic substrate are improved. On the other hand, the SiC particles are further coated with aluminum oxide, and since the matrix material of the ceramic substrate is aluminum oxide, the compatibility with the matrix material is improved, so that the mechanical properties of the prepared ceramic substrate are further improved. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to 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 of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts are within the scope of the present application.

[0045] In the following examples and comparative examples, the average particle size of magnesium oxide is 20 nm; the average particle size of calcium oxide is 40 nm; the average particle size of SiC powder is 30 μm; the length of zirconium oxide whisker is 30 μm, and the diameter is 3 μm; the type of polyethylene glycol is PEG-1000; and the type of polyvinyl butyral is TB-20.

[0046] Example 1

[0047] The preparation method of the modified SiC particles comprises the following steps:

[0048] A1, 1 g of SiC powder is dispersed in 300 mL of ethanol, ultrasonic treatment is performed for 30 min, 26 wt% of ammonia water is added to adjust the pH to 7.5, 3 mL of tetraethyl orthosilicate is added dropwise at a speed of 0.15 mL / min, stirring is performed at 40℃ for 4.5 h, centrifugation, alcohol washing, and drying are performed, and then SiO2-coated SiC particles are obtained;

[0049] A2, 1 g of SiO2-coated SiC particles is dispersed in 100 mL of water, 10 mL of acetic acid-sodium acetate buffer solution is added, 100 mL of Al(NO3)3 solution with a concentration of 0.15 mol / L is added dropwise at a speed of 3 mL / min, ultrasonic treatment and stirring are performed, 26 wt% of ammonia water is added to adjust the pH to 6.5, and then the mixture is kept at 70℃ for 40 min, alcohol washing and drying are performed, and then modified SiC particles are obtained;

[0050] The preparation method of the low-warp multilayer ceramic substrate comprises the following steps:

[0051] S1, 90 parts of aluminum oxide, 3 parts of cetyltrimethylammonium bromide, 4 parts of polyethylene glycol, 10 parts of polyvinyl butyral, 3 parts of magnesium oxide, 70 parts of ethanol, and 6 parts of modified SiC particles are mixed, and then flow casting is performed, and drying is performed to obtain a green ceramic sheet;

[0052] S2, the green ceramic sheet is subjected to punching and hole filling, and then surface printing, lamination of 40 layers, pressure bonding, upper and lower conduction, cutting, sintering at 1600℃ for 4 h, and cooling are performed to obtain a low-warp multilayer ceramic substrate.

[0053] Example 2

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

[0055] A1, 1g SiC powder was dispersed in 300mL ethanol, ultrasonic for 30min, 26wt% ammonia was added to adjust pH to 9.5, 5mL tetraethyl orthosilicate was added at a speed of 0.2mL / min, stirred at 50℃ for 4h, centrifuged, alcohol washed, and dried to obtain SiO2-coated SiC particles;

[0056] A2, 1g SiO2-coated SiC particles were dispersed in 100mL water, 10mL acetic acid-sodium acetate buffer solution was added, 110mL Al(NO3)3 solution with a concentration of 0.15mol / L was added at a speed of 3.5mL / min, ultrasonic, stirred, 26wt% ammonia was added to adjust pH to 7.5, and the mixture was incubated at 80℃ for 30min, alcohol washed, and dried to obtain modified SiC particles;

[0057] A method for preparing a low-warp multilayer ceramic substrate, comprising the following steps:

[0058] S1, 110 parts of alumina, 4 parts of cetyltrimethylammonium bromide, 3 parts of polyethylene glycol, 3 parts of glycerol, 12 parts of polyvinyl butyral, 2 parts of magnesium oxide, 2 parts of calcium oxide, 40 parts of ethanol, 40 parts of isopropanol, and 9 parts of modified SiC particles were mixed according to weight parts, and then flow casting, drying, to obtain a green ceramic sheet;

[0059] S2, the green ceramic sheet was punched, the holes were filled, and then surface printing, 40 layers of lamination, upper and lower conduction, cutting, sintering at 1600℃ for 4h, and cooling to obtain a low-warp multilayer ceramic substrate.

[0060] Example 3

[0061] A method for preparing modified SiC particles, comprising the following steps:

[0062] A1, 1g SiC powder was dispersed in 300mL ethanol, ultrasonic for 30min, 26wt% ammonia was added to adjust pH to 8.5, 4mL tetraethyl orthosilicate was added at a speed of 0.18mL / min, stirred at 40℃ for 4h, centrifuged, alcohol washed, and dried to obtain SiO2-coated SiC particles;

[0063] A2, 1g SiO2-coated SiC particles were dispersed in 100mL water, 10mL acetic acid-sodium acetate buffer solution was added, 105mL Al(NO3)3 solution with a concentration of 0.15mol / L was added at a speed of 3.2mL / min, ultrasonic, stirred, 26wt% ammonia was added to adjust pH to 7, and the mixture was incubated at 75℃ for 35min, alcohol washed, and dried to obtain modified SiC particles;

[0064] A method for preparing a low-warp multilayer ceramic substrate, comprising the following steps:

[0065] S1, 100 parts of alumina, 3.5 parts of cetyltrimethylammonium bromide, 5 parts of glycerol, 11 parts of polyvinyl butyral, 3.5 parts of calcium oxide, 75 parts of isopropyl alcohol, 7 parts of modified SiC particles were mixed in parts by weight, and then cast, dried to obtain a green ceramic sheet;

[0066] S2, the green ceramic sheet was punched, filled, printed, laminated 40 layers, and then sintered at 1600℃ for 4h, cooled to obtain a low warpage multilayer ceramic substrate.

[0067] Example 4

[0068] The difference between this embodiment and example 2 is only that in step S1, 110 parts of alumina, 4 parts of cetyltrimethylammonium bromide, 3 parts of polyethylene glycol, 3 parts of glycerol, 12 parts of polyvinyl butyral, 2 parts of magnesium oxide, 2 parts of calcium oxide, 40 parts of ethanol, 40 parts of isopropyl alcohol, 4.5 parts of modified SiC particles, and 4.5 parts of zirconia whiskers were mixed in parts by weight, and then cast, dried to obtain a green ceramic sheet.

[0069] Example 5

[0070] The difference between this embodiment and example 2 is only that in step S1, 110 parts of alumina, 4 parts of cetyltrimethylammonium bromide, 3 parts of polyethylene glycol, 3 parts of glycerol, 12 parts of polyvinyl butyral, 2 parts of magnesium oxide, 2 parts of calcium oxide, 40 parts of ethanol, 40 parts of isopropyl alcohol, 3 parts of modified SiC particles, and 6 parts of zirconia whiskers were mixed in parts by weight, and then cast, dried to obtain a green ceramic sheet.

[0071] Example 6

[0072] The difference between this embodiment and example 2 is only that in step S1, 110 parts of alumina, 4 parts of cetyltrimethylammonium bromide, 3 parts of polyethylene glycol, 3 parts of glycerol, 12 parts of polyvinyl butyral, 2 parts of magnesium oxide, 2 parts of calcium oxide, 40 parts of ethanol, 40 parts of isopropyl alcohol, 3.6 parts of modified SiC particles, and 5.4 parts of zirconia whiskers were mixed in parts by weight, and then cast, dried to obtain a green ceramic sheet.

[0073] Example 7

[0074] The difference between this embodiment and example 2 is only that in step S1, 110 parts of alumina, 4 parts of cetyltrimethylammonium bromide, 3 parts of polyethylene glycol, 3 parts of glycerol, 12 parts of polyvinyl butyral, 2 parts of magnesium oxide, 2 parts of calcium oxide, 40 parts of ethanol, 40 parts of isopropyl alcohol, 2.5 parts of modified SiC particles, and 6.5 parts of zirconia whiskers were mixed in parts by weight, and then cast, dried to obtain a green ceramic sheet.

[0075] Example 8

[0076] The difference between this embodiment and embodiment 2 is only that in step S1, 110 parts of alumina, 4 parts of cetyltrimethylammonium bromide, 3 parts of polyethylene glycol, 3 parts of glycerol, 12 parts of polyvinyl butyral, 2 parts of magnesium oxide, 2 parts of calcium oxide, 40 parts of ethanol, 40 parts of isopropanol, 6 parts of modified SiC particles, and 3 parts of zirconia whiskers are mixed, and then cast forming, drying to obtain the green ceramic sheet.

[0077] Comparative Example 1

[0078] The difference between this comparative example and embodiment 2 is only that in the preparation of the modified SiC particles, only silica is used to modify the SiC particles. The preparation method of the modified SiC particles comprises the following steps:

[0079] 1g of SiC powder is dispersed in 300mL of ethanol, ultrasonic treatment for 30min, 26wt% ammonia water is added to adjust the pH to 9.5, 5mL of tetraethyl orthosilicate is added dropwise at a speed of 0.2mL / min, stirring at 50℃ for 4h, centrifugation, alcohol washing, and drying to obtain the modified SiC particles.

[0080] Comparative Example 2

[0081] The difference between this comparative example and embodiment 2 is only that in the preparation of the modified SiC particles, only alumina is used to modify the SiC particles. The preparation method of the modified SiC particles comprises the following steps:

[0082] 1g of SiC powder is dispersed in 100mL of water, 10mL of acetic acid-sodium acetate buffer solution is added, 110mL of Al(NO3)3 solution with a concentration of 0.15mol / L is added dropwise at a speed of 3.5mL / min, ultrasonic treatment, stirring, 26wt% ammonia water is added to adjust the pH to 7.5, incubation at 80℃ for 30min, alcohol washing, and drying to obtain the modified SiC particles.

[0083] Comparative Example 3

[0084] The difference between this comparative example and embodiment 2 is only that in the preparation of the low-warp multilayer ceramic substrate, the modified SiC particles are replaced by SiC powder.

[0085] Comparative Example 4

[0086] The difference between this comparative example and embodiment 2 is only that in step S1, 110 parts of alumina, 4 parts of cetyltrimethylammonium bromide, 3 parts of polyethylene glycol, 3 parts of glycerol, 12 parts of polyvinyl butyral, 2 parts of magnesium oxide, 2 parts of calcium oxide, 40 parts of ethanol, 40 parts of isopropanol, and 9 parts of zirconia whiskers are mixed, and then cast forming, drying to obtain the green ceramic sheet.

[0087] Experimental Example 1

[0088] The low warpage multilayer ceramic substrates prepared from Examples 1-8 and Comparative Examples 1-4 were respectively tested for mechanical properties:

[0089] Fracture toughness: the test method was three-point bending according to the test method specified in GB / T 23806-2009 “Fine Ceramics Fracture Toughness Test Method Single Edge Pre-cracked Beam (SEPB) Method”;

[0090] Bending strength: the test method was three-point bending according to the test method specified in GB / T 6569-2006 “Fine Ceramics Bending Strength Test Method”;

[0091] The results are shown in Table 1 below.

[0092] Table 1: Mechanical property test results

[0093]

[0094] By comparing the data of Example 2 with Comparative Examples 1-3, the fracture toughness and bending strength of the multilayer ceramic substrate prepared by using silicon dioxide and aluminum oxide in combination to modify SiC particles in Example 2 are significantly increased compared with Comparative Examples 1-3, which indicates that the mechanical properties of the prepared multilayer ceramic substrate can be significantly improved by using silicon dioxide and aluminum oxide in combination to modify SiC particles.

[0095] By comparing the data of Example 2, Examples 4-8, and Comparative Example 4, the fracture toughness and bending strength of the multilayer ceramic substrate prepared by introducing zirconium oxide whiskers in combination with modified SiC particles in Examples 4-8 are significantly increased compared with Example 2 and Comparative Example 4, which indicates that the mechanical properties of the prepared multilayer ceramic substrate can be improved by using zirconium oxide whiskers in combination with modified SiC particles; and by comparing the data of Examples 4-8, the fracture toughness and bending strength of the multilayer ceramic substrate prepared by adjusting the mass ratio of modified SiC particles and zirconium oxide whiskers in Examples 4-6 are further increased compared with Examples 7-8, which indicates that the mechanical properties of the prepared multilayer ceramic substrate can be further improved by adjusting the mass ratio of modified SiC particles and zirconium oxide whiskers, and when the mass ratio of modified SiC particles and zirconium oxide whiskers is 1:1-2.

[0096] Experimental Example 2

[0097] The low warpage multilayer ceramic substrates prepared from Examples 1-3 were respectively tested for warpage, and the results are shown in Table 2:

[0098] Warpage: warpage is tested by using a plug gauge measurement method; the test method comprises the following steps: using a plug gauge, starting from one corner of the substrate, inserting the plug gauge, measuring the height of the corner, and then sequentially measuring the heights of the other corners of the substrate, and recording the height values of each corner.

[0099] Warpage: the ceramic substrate is freely placed on a plane, the height differences of the four corners and the center are measured, and the warpage is calculated according to the following formula:

[0100]

[0101] In the above formula, δmax is the maximum height difference, δmin is the minimum height difference, and L is the diagonal length of the ceramic substrate.

[0102] Table 2 Test results of warpage

[0103]

[0104] It can be found from the data in Table 2 that the warpage of the ceramic substrate prepared by the present application is ≤0.13%, indicating that the ceramic substrate prepared by the present application has a lower warpage.

[0105] 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 principles of the present application shall be included in the protection scope of the present application.

Claims

1. A low warpage multilayer ceramic substrate, characterized by, Raw materials including the following weight parts: alumina 90~110 parts, dispersant 3~4 parts, plasticizer 4~6 parts, binder 10~12 parts, sintering aid 3~4 parts, solvent 70~80 parts, functional aid 6~9 parts; The functional aid includes modified SiC particles; The modified SiC particles are SiC particles coated with SiO2 and Al2O3 in sequence; The functional aid also includes zirconia whiskers; The mass ratio of the modified SiC particles and the zirconia whiskers is 1:1~2.

2. The low warpage multilayer ceramic substrate according to claim 1, characterized by, The preparation method of the modified SiC particles includes the following steps: A1, dispersing SiC powder in ethanol, adding ammonia water to adjust pH to 7.5~9.5, adding tetraethyl orthosilicate dropwise, stirring, centrifuging, alcohol washing, and drying to obtain SiO2-coated SiC particles; A2, dispersing the SiO2-coated SiC particles in water, adding a buffer solution, then adding Al(NO3)3 solution dropwise, ultrasonicating, stirring, adding ammonia water to adjust pH to 6.5~7.5, incubating, alcohol washing, and drying to obtain modified SiC particles.

3. The low warpage multilayer ceramic substrate of claim 2, wherein, In step A1, the stirring temperature is 40~50℃, and the stirring time is 4~4.5h; In step A2, the incubation temperature is 70~80℃, and the incubation time is 30~40min.

4. The low warpage multilayer ceramic substrate of claim 2, wherein, The mass-volume ratio of the SiC powder and the tetraethyl orthosilicate is 1g:3~5mL; The concentration of the Al(NO3)3 solution is 0.1~0.2mol / L; The mass-volume ratio of the SiO2-coated SiC particles and the Al(NO3)3 solution is 1g:100~110mL.

5. The low warpage multilayer ceramic substrate of claim 2, wherein, In step A1, the dropwise adding speed of the tetraethyl orthosilicate is 0.15~0.2mL / min; In step A2, the dropwise adding speed of the Al(NO3)3 solution is 3~3.5mL / min.

6. The low warpage multilayer ceramic substrate of claim 1, wherein, The sintering aid includes one or both of magnesium oxide and calcium oxide; The solvent includes one or both of ethanol and isopropyl alcohol.

7. The low warpage multilayer ceramic substrate of claim 1, wherein, The dispersant includes cetyltrimethylammonium bromide; The plasticizer includes one or both of polyethylene glycol and glycerol.

8. The low warpage multilayer ceramic substrate of claim 1, wherein, The binder includes polyvinyl butyral.

9. A method for producing a low warpage multilayer ceramic substrate according to any one of claims 1 to 8, characterized by, The method includes the following steps: S1, mixing raw materials, flow casting, drying, and obtaining green ceramic sheets; S2, punching and filling the green ceramic sheets, surface printing, laminating and pressing, up and down conduction, cutting, sintering, and cooling to obtain a low-warp multilayer ceramic substrate.

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