A high thermal conductivity aluminum nitride ceramic substrate and its preparation method

Abstract

This invention relates to the field of ceramic substrate technology, and proposes a high thermal conductivity aluminum nitride ceramic substrate and its preparation method. The high thermal conductivity aluminum nitride ceramic substrate comprises the following raw materials in parts by weight: 80-90 parts aluminum nitride, 40-50 parts solvent, 1-3 parts dispersant, 10-15 parts binder, 3-5 parts sintering aid, and 2-6 parts plasticizer; the sintering aid includes titanium nitride and / or magnesium silicide. This technical solution solves the problem of low thermal conductivity in aluminum nitride ceramic substrates in related technologies.

Description

Technical Field

[0001] This invention relates to the field of ceramic substrate technology, specifically to a high thermal conductivity aluminum nitride ceramic substrate and its preparation method. Background Technology

[0002] Aluminum nitride ceramic substrate is a ceramic substrate made from aluminum nitride as the main raw material through processing technology. Due to its excellent performance characteristics, aluminum nitride ceramic substrate has become an indispensable key material in many fields such as power semiconductors, high-frequency communications, optoelectronics and aerospace, playing an important role in the high-performance and high-reliability operation of electronic devices.

[0003] However, the fabrication of aluminum nitride ceramic substrates still faces numerous technical challenges, one of which is low thermal conductivity. In electronic devices, especially in high-power-density applications, low thermal conductivity means that the heat generated by the chip cannot be quickly and effectively dissipated. For high-power integrated circuits, the accumulation of heat will cause the chip's operating temperature to rise sharply, which will significantly reduce the chip's performance and reliability, and greatly shorten the lifespan of electronic devices. Therefore, it is essential to develop an aluminum nitride ceramic substrate with high thermal conductivity. Summary of the Invention

[0004] This invention proposes a high thermal conductivity aluminum nitride ceramic substrate and its preparation method, which solves the problem of low thermal conductivity of aluminum nitride ceramic substrates in related technologies.

[0005] The technical solution of the present invention is as follows: The present invention proposes a high thermal conductivity aluminum nitride ceramic substrate, comprising the following raw materials in parts by weight: 80-90 parts aluminum nitride, 40-50 parts solvent, 1-3 parts dispersant, 10-15 parts binder, 3-5 parts sintering aid, and 2-6 parts plasticizer;

[0006] The sintering aids include titanium nitride and / or magnesium silicide.

[0007] As a further technical solution, when the sintering aid is composed of titanium nitride and magnesium silicide, the mass ratio of titanium nitride to magnesium silicide is 1:1~2.

[0008] In this invention, titanium nitride and magnesium silicide are added simultaneously as sintering aids to exert their synergistic effect, effectively inhibit excessive grain growth, promote grain size uniformity, and further improve the thermal conductivity of the ceramic substrate.

[0009] As a further technical solution, the dispersant includes a first dispersant, which includes one or more of polyethylene glycol, polyvinyl alcohol, and polyacrylic acid.

[0010] As a further technical solution, the dispersant also includes a second dispersant and a third dispersant. The second dispersant includes one or more of sodium hexametaphosphate, sodium pyrophosphate, and sodium silicate. The third dispersant is a sodium mercaptosulfonate salt, which includes one or more of sodium 2-hydroxy-3-mercaptopropanesulfonate, sodium 3-mercapto-1-propanesulfonate, and sodium dimercaptopropanesulfonate.

[0011] As a further technical solution, the mass ratio of the first dispersant, the second dispersant, and the third dispersant is 2~3:1:1.

[0012] In this invention, a first dispersant, a second dispersant, and a third dispersant are added simultaneously to exert their synergistic effect. Through the interaction between the dispersant and aluminum nitride, titanium nitride, and magnesium silicide, particle agglomeration is effectively prevented, further enhancing the particle dispersion effect and further improving the strength of the ceramic substrate.

[0013] As a further technical solution, the solvent includes one or more of ethanol, isopropanol, and ethyl acetate.

[0014] As a further technical solution, the adhesive includes one or both of polyvinyl butyral and polymethyl methacrylate.

[0015] In this invention, a binder is added during the preparation of the ceramic substrate. The binder has good bonding properties and can effectively bond various powder particles such as aluminum nitride and sintering aids together. They form bridges between particles, increase the cohesive force between particles, and keep the shape of the green body stable during the forming process, avoiding defects such as cracking and delamination.

[0016] As a further technical solution, the plasticizer includes one or more of dibutyl phthalate, dioctyl phthalate, and dioctyl adipate.

[0017] In this invention, adding a plasticizer during the preparation of the ceramic substrate can increase its flexibility and fluidity, and significantly improve the plasticity of the green body.

[0018] This invention also proposes a method for preparing a high thermal conductivity aluminum nitride ceramic substrate, comprising the following steps:

[0019] S1. Weigh the raw materials in the specified weight proportions, mix them evenly, and then ball-mill and granulate them to obtain a mixture;

[0020] S2. After injection molding, debinding, and sintering, the mixture yields an aluminum nitride ceramic substrate.

[0021] As a further technical solution, the sintering temperature is 1750~1850℃, and the sintering time is 2~4h.

[0022] As a further technical solution, the ball milling time is 6-8 hours and the ball milling rate is 180 r / min.

[0023] As a further technical solution, the glue discharge temperature is 800℃ and the glue discharge time is 2 hours.

[0024] The working principle and beneficial effects of this invention are as follows:

[0025] In this invention, aluminum nitride is used as the main material, and titanium nitride and / or magnesium silicide are added as sintering aids to prepare a ceramic substrate. By consuming the silicates present on the surface of aluminum nitride, impurities at the grain boundaries are reduced. By forming a liquid phase, the growth and arrangement of grains are promoted, which helps to form a denser and more uniform microstructure, thereby improving the thermal conductivity of the ceramic substrate. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] In the following examples and comparative examples:

[0028] Polyethylene glycol: Model number PEG600;

[0029] Polyvinyl alcohol: Model number PVA17-88;

[0030] Polyacrylic acid: molecular weight 5000, solid content 30wt%;

[0031] Polyvinyl butyral: Butyral content 76wt%, hydroxyl content 14wt%, viscosity 100cps;

[0032] Polymethyl methacrylate: Model number PMMA CM-211;

[0033] Aluminum nitride: average particle size 1~2μm, hexagonal crystal form;

[0034] Titanium nitride: average particle size 1~3μm, cubic crystal form;

[0035] Magnesium silicide: average particle size 3 μm;

[0036] Magnesium oxide: average particle size is 1~3μm;

[0037] Lanthanum oxide: average particle size is 1~3μm.

[0038] Example 1

[0039] A method for preparing a high thermal conductivity aluminum nitride ceramic substrate includes the following steps:

[0040] S1. Weigh 80 parts of aluminum nitride, 40 parts of ethanol, 1 part of dispersant, 10 parts of polyvinyl butyral, 3 parts of sintering aid, and 2 parts of dibutyl phthalate. Mix them evenly and then ball mill them at 180 r / min for 6 h to produce granules and obtain a mixture. The dispersant is polyethylene glycol and the sintering aid is titanium nitride.

[0041] S2. Inject the mixture into the ceramic substrate mold, cure for 15 minutes, demold to obtain the green body, remove the binder at 800℃ for 2 hours, and then sinter at 1750℃ for 4 hours to obtain the aluminum nitride ceramic substrate.

[0042] Example 2

[0043] A method for preparing a high thermal conductivity aluminum nitride ceramic substrate includes the following steps:

[0044] S1. Weigh 85 parts of aluminum nitride, 45 parts of isopropanol, 2 parts of dispersant, 12 parts of polyvinyl butyral, 4 parts of sintering aid, and 4 parts of dioctyl phthalate. Mix them evenly and then ball mill them at 180 r / min for 7 h to produce granules and obtain a mixture. The dispersant is polyvinyl alcohol and the sintering aid is titanium nitride.

[0045] S2. Inject the mixture into the ceramic substrate mold, cure for 15 minutes, demold to obtain the green body, remove the binder at 800℃ for 2 hours, and then sinter at 1800℃ for 3 hours to obtain the aluminum nitride ceramic substrate.

[0046] Example 3

[0047] A method for preparing a high thermal conductivity aluminum nitride ceramic substrate includes the following steps:

[0048] S1. Weigh 90 parts of aluminum nitride, 50 parts of ethyl acetate, 3 parts of dispersant, 15 parts of polymethyl methacrylate, 5 parts of sintering aid, and 6 parts of dioctyl adipate. Mix them evenly and then ball mill them at 180 r / min for 8 hours to produce granules and obtain a mixture. The dispersant is polyacrylic acid and the sintering aid is titanium nitride.

[0049] S2. Inject the mixture into the ceramic substrate mold, cure for 15 minutes, demold to obtain the green body, remove the binder at 800℃ for 2 hours, and then sinter at 1850℃ for 2 hours to obtain the aluminum nitride ceramic substrate.

[0050] Example 4

[0051] The difference between Example 4 and Example 1 is that the sintering aid is magnesium silicide.

[0052] Example 5

[0053] The difference between Example 1 and Example 5 is that the sintering aid consists of titanium nitride and magnesium silicide in a mass ratio of 1:1.

[0054] Example 6

[0055] The difference between Example 6 and Example 1 is that the sintering aid consists of titanium nitride and magnesium silicide in a mass ratio of 1:2.

[0056] Example 7

[0057] The difference between Example 7 and Example 6 is that the dispersant is sodium hexametaphosphate and sodium 2-hydroxy-3-mercaptopropanesulfonate in a mass ratio of 1:1.

[0058] Example 8

[0059] The difference between Example 8 and Example 7 is that the dispersant is composed of polyethylene glycol, sodium hexametaphosphate, and sodium 2-hydroxy-3-mercaptopropanesulfonate in a mass ratio of 2:1:1.

[0060] Example 9

[0061] The difference between Example 9 and Example 7 is that the dispersant is composed of polyethylene glycol, sodium hexametaphosphate, and sodium 2-hydroxy-3-mercaptopropanesulfonate in a mass ratio of 3:1:1.

[0062] Example 10

[0063] The difference between Example 10 and Example 9 is that sodium 2-hydroxy-3-mercaptopropanesulfonate is replaced with an equal amount of sodium 3-mercapto-1-propanesulfonate.

[0064] Example 11

[0065] The difference between Example 11 and Example 9 is that sodium 2-hydroxy-3-mercaptopropanesulfonate is replaced with an equal amount of sodium dimercaptopropanesulfonate.

[0066] Example 12

[0067] The difference between Example 12 and Example 9 is that sodium 2-hydroxy-3-mercaptopropanesulfonate is replaced with an equal amount of sodium octanesulfonate.

[0068] Comparative Example 1

[0069] The difference between Comparative Example 1 and Example 1 is that no sintering aid was added.

[0070] Comparative Example 2

[0071] The difference between Comparative Example 2 and Example 1 is that the sintering aid is lanthanum oxide.

[0072] Comparative Example 3

[0073] The difference between Comparative Example 3 and Example 1 is that the sintering aid is magnesium oxide.

[0074] Experimental Example 1

[0075] The thermal conductivity of the aluminum nitride ceramic substrates with dimensions of 130mm×130mm×5mm prepared in Examples 1-6 and Comparative Examples 1-3 was tested according to the test methods specified in GB / T 39862-2021 "Test of thermal conductivity of high thermal conductivity ceramics".

[0076] The test results are shown in Table 1:

[0077] Table 1 Performance test results of aluminum nitride ceramic substrates prepared in Examples 1-6 and Comparative Examples 1-3

[0078]

[0079] As can be seen from Table 1, the thermal conductivity of Examples 1 to 6 is as high as 220 W / (m·k), indicating that adding titanium nitride and / or magnesium silicide as sintering aids can improve the thermal conductivity of aluminum nitride ceramic substrates.

[0080] Experiment Example 2

[0081] The bending strength of the aluminum nitride ceramic substrates with dimensions of 130mm×130mm×5mm prepared in Examples 6-12 was tested according to the test method specified in GB / T6569-2006 "Test Method for Bending Strength of Fine Ceramics".

[0082] The test results are shown in Table 2:

[0083] Table 2 Performance test results of aluminum nitride ceramic substrates prepared in Examples 6-12

[0084]

[0085] As can be seen from Table 2, the flexural strength of Examples 8 to 11 is as high as 427 MPa or more, indicating that the first dispersant, the second dispersant, and the third dispersant play a synergistic role and can further improve the strength of the aluminum nitride ceramic substrate.

[0086] Experimental Example 3

[0087] 1. Surface roughness: The surface roughness of the aluminum nitride ceramic substrate prepared in Example 1 was tested according to the test method specified in GB / T 13841-1992 "Surface Roughness of Electronic Ceramic Parts".

[0088] 2. Volume resistivity: The volume resistivity of the aluminum nitride ceramic substrate prepared in Example 1 was tested according to the test method specified in GB 5594.5-1985 "Test Method for Performance of Structural Ceramic Materials for Electronic Components - Test Method for Volume Resistivity".

[0089] 3. Dielectric constant: According to the test method specified in GB / T 5594.4-2015 "Test methods for performance of structural ceramic materials for electronic components - Part 4: Test method for dielectric constant and dielectric loss tangent", the aluminum nitride ceramic substrate prepared in Example 1 was sampled according to the standard size, and the dielectric constant of the sample was tested.

[0090] 4. Breakdown strength: According to the test method specified in GB / T 5593-2015 "Structural Ceramic Materials for Electronic Components", the aluminum nitride ceramic substrate prepared in Example 1 was sampled according to the standard dimensions, and the breakdown strength of the sample was tested.

[0091] The test results are shown in Table 3:

[0092] Table 3 Performance test results of the aluminum nitride ceramic substrate prepared in Example 1

[0093]

[0094] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high thermal conductivity aluminum nitride ceramic substrate, characterized in that, The raw materials include the following components in parts by weight: 80-90 parts aluminum nitride, 40-50 parts solvent, 1-3 parts dispersant, 10-15 parts binder, 3-5 parts sintering aid, and 2-6 parts plasticizer; when the sintering aid is composed of titanium nitride and magnesium silicide, the mass ratio of titanium nitride to magnesium silicide is 1:1-2.

2. The high thermal conductivity aluminum nitride ceramic substrate according to claim 1, characterized in that, The dispersant includes a first dispersant, which includes one or more of polyethylene glycol, polyvinyl alcohol, and polyacrylic acid.

3. The high thermal conductivity aluminum nitride ceramic substrate according to claim 2, characterized in that, The dispersant further includes a second dispersant and a third dispersant. The second dispersant includes one or more of sodium hexametaphosphate, sodium pyrophosphate, and sodium silicate. The third dispersant is a sodium mercaptosulfonate salt, which includes one or more of sodium 2-hydroxy-3-mercaptopropanesulfonate, sodium 3-mercapto-1-propanesulfonate, and sodium dimercaptopropanesulfonate.

4. The high thermal conductivity aluminum nitride ceramic substrate according to claim 2, characterized in that, The mass ratio of the first dispersant, the second dispersant, and the third dispersant is 2~3:1:

1.

5. The high thermal conductivity aluminum nitride ceramic substrate according to claim 1, characterized in that, The solvent includes one or more of ethanol, isopropanol, and ethyl acetate.

6. The high thermal conductivity aluminum nitride ceramic substrate according to claim 1, characterized in that, The adhesive includes one or both of polyvinyl butyral and polymethyl methacrylate.

7. The high thermal conductivity aluminum nitride ceramic substrate according to claim 1, characterized in that, The plasticizer includes one or more of dibutyl phthalate, dioctyl phthalate, and dioctyl adipate.

8. A method for preparing a high thermal conductivity aluminum nitride ceramic substrate according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Weigh the raw materials in the specified weight proportions, mix them evenly, and then ball-mill and granulate them to obtain a mixture; S2. After injection molding, debinding, and sintering, the mixture yields an aluminum nitride ceramic substrate.

9. The method for preparing a high thermal conductivity aluminum nitride ceramic substrate according to claim 8, characterized in that, The sintering temperature is 1750~1850℃, and the sintering time is 2~4h.

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