High-thermal-conductivity aluminum nitride ceramic substrate and preparation method thereof

Abstract

The invention relates to the technical field of ceramic substrates, and provides a high-thermal-conductivity aluminum nitride ceramic substrate and a preparation method thereof. The high-thermal-conductivity aluminum nitride ceramic substrate comprises the following raw materials in parts by weight: 80-90 parts of aluminum nitride, 40-50 parts of a solvent, 1-3 parts of a dispersant, 10-15 parts of a binder, 3-5 parts of a sintering aid and 2-6 parts of a plasticizer. The sintering aid comprises titanium nitride and / or magnesium silicide. According to the technical scheme, the problem of low thermal conductivity of the aluminum nitride ceramic substrate in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic substrates, and specifically, to a high thermal conductivity aluminum nitride ceramic substrate and a preparation method thereof. Background Art

[0002] An aluminum nitride ceramic substrate is a ceramic substrate mainly made of aluminum nitride through a processing technology. With its excellent performance characteristics, the aluminum nitride ceramic substrate has become an indispensable key basic 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, there are still many technical challenges in the preparation process of aluminum nitride ceramic substrates, and low thermal conductivity is one of them. In electronic devices, especially in the application scenarios of high-power density electronic devices, low thermal conductivity means that the heat generated by the chip cannot be quickly and effectively conducted out. For high-power integrated circuits, the accumulation of heat will cause the chip operating temperature to rise sharply, which will significantly reduce the performance and reliability of the chip and greatly shorten the service life of electronic devices. Therefore, it is necessary to develop an aluminum nitride ceramic substrate with high thermal conductivity. Summary of the Invention

[0004] The present invention provides a high thermal conductivity aluminum nitride ceramic substrate and a preparation method thereof, which solve 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 provides a high thermal conductivity aluminum nitride ceramic substrate, which comprises the following raw materials in parts by weight: 80 - 90 parts of aluminum nitride, 40 - 50 parts of solvent, 1 - 3 parts of dispersant, 10 - 15 parts of binder, 3 - 5 parts of sintering aid, and 2 - 6 parts of plasticizer; The sintering aid includes titanium nitride and / or magnesium silicide.

[0006] As a further technical solution, when the sintering aid consists of titanium nitride and magnesium silicide, the mass ratio of titanium nitride to magnesium silicide is 1:1 - 2.

[0007] In the present invention, titanium nitride and magnesium silicide are added simultaneously as sintering aids to exert their synergistic effect, effectively inhibit the excessive growth of grains, promote the uniformity of grain size, and further improve the thermal conductivity of the ceramic substrate.

[0008] As a further technical solution, the dispersant includes a first dispersant, and the first dispersant includes one or more of polyethylene glycol, polyvinyl alcohol, and polyacrylic acid.

[0009] As a further technical solution, 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 mercapto sulfonate salt, and the sodium mercapto sulfonate salt includes one or more of 2-hydroxy-3-mercaptopropanesulfonic acid sodium salt, 3-mercapto-1-propanesulfonic acid sodium salt, and sodium dimercaptopropanesulfonate.

[0010] As a further technical solution, the mass ratio of the first dispersant, the second dispersant, and the third dispersant is 2-3:1:1.

[0011] In the present invention, the first dispersant, the second dispersant, and the third dispersant are added simultaneously to exert their synergistic effects. Through the interaction between the dispersant and aluminum nitride, titanium nitride, and magnesium silicide, the agglomeration of particles is effectively prevented, the dispersion effect of the particles is further enhanced, and the strength of the ceramic substrate is further improved.

[0012] As a further technical solution, the solvent includes one or more of ethanol, isopropanol, and ethyl acetate.

[0013] As a further technical solution, the binder includes one or two of polyvinyl butyral and polymethyl methacrylate.

[0014] In the present 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 the particles, increasing the cohesive force between the particles and keeping the shape of the green body stable during the forming process, avoiding defects such as cracking and delamination.

[0015] As a further technical solution, the plasticizer includes one or more of dibutyl phthalate, dioctyl phthalate, and dioctyl adipate.

[0016] In the present invention, a plasticizer is added during the preparation of the ceramic substrate, which can increase its flexibility and fluidity and significantly improve the plasticity of the green body.

[0017] The present invention also provides a method for preparing a high thermal conductivity aluminum nitride ceramic substrate, which includes the following steps: S1. Weigh the raw materials of the above-mentioned weight parts, mix them evenly, and then obtain a mixed material through ball milling and granulation. S2. After injection molding, debinding, and sintering of the mixed material, an aluminum nitride ceramic substrate is obtained.

[0018] As a further technical solution, the sintering temperature is 1750-1850 °C, and the sintering time is 2-4 h.

[0019] As a further technical solution, the ball milling time is 6 to 8 h, and the ball milling rate is 180 r / min.

[0020] As a further technical solution, the debinding temperature is 800 °C, and the debinding time is 2 h.

[0021] The working principle and beneficial effects of the present invention are as follows: In the present invention, using aluminum nitride as the main raw material, adding titanium nitride and / or magnesium silicide as sintering aids to prepare a ceramic substrate. By consuming the silicate existing on the surface of aluminum nitride, the impurities at the grain boundaries are reduced, and the growth and arrangement of grains are promoted by forming a liquid phase, which helps to form a denser and more uniform microstructure, thereby improving the thermal conductivity of the ceramic substrate. Specific Embodiments

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0023] In the following examples and comparative examples: Polyethylene glycol: The model is PEG600; Polyvinyl alcohol: The model is PVA17-88; Polyacrylic acid: The molecular weight is 5000, and the solid content is 30 wt%; Polyvinyl butyral: The butyraldehyde content is 76 wt%, the hydroxyl content is 14 wt%, and the viscosity is 100 cps; Polymethyl methacrylate: The model is PMMA CM-211; Aluminum nitride: The average particle size is 1 to 2 μm, hexagonal crystal form; Titanium nitride: The average particle size is 1 to 3 μm, cubic crystal form; Magnesium silicide: The average particle size is 3 μm; Magnesium oxide: The average particle size is 1 to 3 μm; Lanthanum oxide: The average particle size is 1 to 3 μm.

[0024] Example 1 A preparation method of a high thermal conductivity aluminum nitride ceramic substrate includes the following steps: 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. After mixing evenly, ball mill at 180 r / min for 6 h to prepare granulated powder to obtain a mixture, where the dispersant is polyethylene glycol and the sintering aid is titanium nitride; S2. Inject the mixture into the ceramic substrate model, demold after curing for 15 min to obtain a green body, degrease at 800 °C for 2 h, and then sinter at 1750 °C for 4 h to obtain the aluminum nitride ceramic substrate.

[0025] Example 2 A preparation method of a high thermal conductivity aluminum nitride ceramic substrate, comprising the following steps: S1. Weigh 85 parts of aluminum nitride, 45 parts of isopropyl alcohol, 2 parts of dispersant, 12 parts of polyvinyl butyral, 4 parts of sintering aid, and 4 parts of dioctyl phthalate. After mixing evenly, ball mill at 180 r / min for 7 h to produce granular powder and obtain the mixture. The dispersant is polyvinyl alcohol, and the sintering aid is titanium nitride; S2. Inject the mixture into the ceramic substrate model, demold after curing for 15 min to obtain a green body, degrease at 800 °C for 2 h, and then sinter at 1800 °C for 3 h to obtain the aluminum nitride ceramic substrate.

[0026] Example 3 A preparation method of a high thermal conductivity aluminum nitride ceramic substrate, comprising the following steps: 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. After mixing evenly, ball mill at 180 r / min for 8 h to produce granular powder and obtain the mixture. The dispersant is polyacrylic acid, and the sintering aid is titanium nitride; S2. Inject the mixture into the ceramic substrate model, demold after curing for 15 min to obtain a green body, degrease at 800 °C for 2 h, and then sinter at 1850 °C for 2 h to obtain the aluminum nitride ceramic substrate.

[0027] Example 4 Compared with Example 1, the difference in Example 4 is that the sintering aid is magnesium silicide.

[0028] Example 5 Compared with Example 1, the difference in Example 5 is that the sintering aid consists of titanium nitride and magnesium silicide with a mass ratio of 1:1.

[0029] Example 6 Compared with Example 1, the difference in Example 6 is that the sintering aid consists of titanium nitride and magnesium silicide with a mass ratio of 1:2.

[0030] Example 7 Compared with Example 6, the difference in Example 7 is that the dispersant is sodium hexametaphosphate and 2-hydroxy-3-mercaptopropanesulfonic acid with a mass ratio of 1:1.

[0031] Example 8 Compared with Example 7, Example 8 is different in that the dispersant is composed of polyethylene glycol, sodium hexametaphosphate, and sodium 2-hydroxy-3-mercaptopropanesulfonate with a mass ratio of 2:1:1.

[0032] Example 9 Compared with Example 7, Example 9 is different in that the dispersant is composed of polyethylene glycol, sodium hexametaphosphate, and sodium 2-hydroxy-3-mercaptopropanesulfonate with a mass ratio of 3:1:1.

[0033] Example 10 Compared with Example 9, Example 10 is different in that sodium 2-hydroxy-3-mercaptopropanesulfonate is replaced with an equal amount of sodium 3-mercapto-1-propanesulfonate.

[0034] Example 11 Compared with Example 9, Example 11 is different in that sodium 2-hydroxy-3-mercaptopropanesulfonate is replaced with an equal amount of sodium dimercaptopropanesulfonate.

[0035] Example 12 Compared with Example 9, Example 12 is different in that sodium 2-hydroxy-3-mercaptopropanesulfonate is replaced with an equal amount of sodium octanesulfonate.

[0036] Comparative Example 1 Compared with Example 1, Comparative Example 1 is different in that no sintering aid is added.

[0037] Comparative Example 2 Compared with Example 1, Comparative Example 2 is different in that the sintering aid is lanthanum oxide.

[0038] Comparative Example 3 Compared with Example 1, Comparative Example 3 is different in that the sintering aid is magnesium oxide.

[0039] Experimental Example 1 The thermal conductivity of the aluminum nitride ceramic substrates with a specification of 130 mm × 130 mm × 5 mm prepared in Examples 1 to 6 and Comparative Examples 1 to 3 was tested according to the test method specified in GB / T 39862-2021 "Detection of Thermal Conductivity of High Thermal Conductivity Ceramics".

[0040] The test results are shown in Table 1: Table 1 Performance test results of aluminum nitride ceramic substrates prepared in Examples 1 to 6 and Comparative Examples 1 to 3

[0041] As can be seen from Table 1, the thermal conductivity of Examples 1 to 6 is as high as over 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.

[0042] Experimental Example 2 For the aluminum nitride ceramic substrates with the specification of 130 mm × 130 mm × 5 mm prepared in Examples 6 to 12, the flexural strength of the samples was tested according to the test method specified in GB / T 6569-2006 "Test Method for Flexural Strength of Fine Ceramics".

[0043] The test results are shown in Table 2: Table 2 Performance Test Results of Aluminum Nitride Ceramic Substrates Prepared in Examples 6 to 12

[0044] As can be seen from Table 2, the flexural strength of Examples 8 to 11 is as high as over 427 MPa, indicating that the first dispersant, the second dispersant, and the third dispersant play a synergistic role, which can further improve the strength of aluminum nitride ceramic substrates.

[0045] Experimental Example 3 1. Surface roughness: The surface roughness of the aluminum nitride ceramic substrate prepared in Example 1 was detected according to the test method specified in GB / T 13841-1992 "Surface Roughness of Electronic Ceramic Components".

[0046] 2. Volume resistivity: The volume resistivity of the aluminum nitride ceramic substrate prepared in Example 1 was detected according to the test method specified in GB 5594.5-1985 "Test Method for Volume Resistivity of Structural Ceramic Materials for Electronic Components".

[0047] 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 Methods for Dielectric Constant and Dissipation Factor", the aluminum nitride ceramic substrate prepared in Example 1 was sampled according to the dimensions in the standard, and the dielectric constant of the sample was tested.

[0048] 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 dimensions in the standard, and the breakdown strength of the sample was tested.

[0049] The test results are shown in Table 3: Table 3 Performance Test Results of Aluminum Nitride Ceramic Substrate Prepared in Example 1

[0050] The above are only the 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 shall be included within the protection scope of the present invention.

Claims

1. A high thermal conductivity aluminum nitride ceramic substrate, characterized in that: The invention comprises the following raw materials in parts by weight: 80-90 parts of aluminum nitride, 40-50 parts of solvent, 1-3 parts of dispersant, 10-15 parts of binder, 3-5 parts of sintering aid and 2-6 parts of plasticizer; the sintering aid comprises titanium nitride and / or magnesium silicide.

2. The high thermal conductivity aluminum nitride ceramic substrate according to claim 1, characterized in that: When the sintering aid consists of titanium nitride and magnesium silicide, the mass ratio of the titanium nitride to the magnesium silicide is 1:1-2.

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

4. The high thermal conductivity aluminum nitride ceramic substrate according to claim 3, characterized in that: 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 sodium mercaptosulfonate, and the sodium mercaptosulfonate includes one or more of sodium 2-hydroxy-3-mercaptopropane sulfonate, sodium 3-mercapto-1-propane sulfonate, and sodium dimercaptopropane sulfonate.

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

1.

6. 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.

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

8. 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.

9. The method for preparing a high thermal conductivity aluminum nitride ceramic substrate according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, weighing the component raw materials in parts by weight, mixing them evenly, and then ball milling them to produce granular powder to obtain a mixed material; S2. After the mixed material is subjected to injection molding, binder removal and sintering, an aluminum nitride ceramic substrate is obtained.

10. The method for preparing a high thermal conductivity aluminum nitride ceramic substrate according to claim 9, characterized in that: The sintering temperature is 1750-1850° C., and the sintering time is 2-4 hours.

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