Preparation method of aluminum nitride ceramic plate

Abstract

The invention provides a preparation method of an aluminum nitride ceramic plate, which comprises the following steps: mixing all raw materials to obtain aluminum nitride slurry, carrying out tape casting to obtain an aluminum nitride tape casting blank with smaller thickness, stacking a plurality of layers of aluminum nitride tape casting blanks, and carrying out hot pressing to obtain the aluminum nitride ceramic plate. And finally, cold isostatic pressing and sintering are carried out in sequence, and the aluminum nitride ceramic plate which is large in size, ultra-thick and high in density can be prepared. According to the preparation method disclosed by the invention, through cooperation of tape casting and hot pressing, the thickness limitation of pure tape casting can be broken through, so that the aluminum nitride ceramic plate with large size, super thickness and high density can be prepared, and the aluminum nitride ceramic plate has excellent heat conductivity and bending resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor components, and particularly relates to a preparation method of an aluminum nitride ceramic disk. Background Art

[0002] With the rapid development of semiconductor technology and the continuous acceleration of the localization process of semiconductor equipment, as a key material for semiconductor equipment, the ALN ceramic disk urgently needs to accelerate the research of this material to achieve the localization of key materials.

[0003] The ALN ceramic disk has attracted people's attention due to its high thermal conductivity, low dielectric constant, high resistivity, thermal expansion coefficient similar to that of silicon, and excellent mechanical and electrical properties. It is the first choice for a new generation of semiconductor materials and has a very broad prospect in the field of semiconductor components. Such as ALN heating disks, E-Chucks, etc., which are widely used in the field of semiconductor equipment.

[0004] At present, the preparation methods of ceramic materials include: slip casting, die pressing, tape casting, and injection molding and other processes. The slip casting process has a long preparation cycle and low production efficiency; the injection molding process is suitable for preparing ceramic parts with complex shapes and small sizes; the tape casting process has the advantages of simple and efficient process, short production cycle, and easy batch production, and is suitable for the preparation of thin-sheet ceramic products. However, the aluminum nitride ceramic disk often requires large size, ultra-thick and high density. The slip casting process and the injection molding process do not meet the requirements of industrial applications, while the tape casting process has a thickness limitation, which is not conducive to the preparation of ultra-thick and high-density aluminum nitride ceramic disks.

[0005] In summary, a new preparation method of an aluminum nitride ceramic disk needs to be developed. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a preparation method of an aluminum nitride ceramic disk. The preparation method mixes all raw materials to obtain aluminum nitride slurry, first obtains an aluminum nitride tape casting blank with a smaller thickness through tape casting, then stacks several layers of the aluminum nitride tape casting blanks and performs hot pressing to increase the thickness and obtain an aluminum nitride hot pressing blank with a target thickness. Finally, cold isostatic pressing and sintering are carried out in sequence to prepare a large-size, ultra-thick, and high-density aluminum nitride ceramic disk. The preparation method of the present invention can break through the thickness limitation of pure tape casting through the cooperation of tape casting and hot pressing, and then can prepare a large-size, ultra-thick, and high-density aluminum nitride ceramic disk, which has excellent thermal conductivity and flexural performance.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] The object of the present invention is to provide a method for preparing an aluminum nitride ceramic disc, and the preparation method includes the following steps:

[0009] (1) Mix aluminum nitride powder, organic solvent, dispersant, binder, and sintering aid evenly to obtain an aluminum nitride slurry;

[0010] (2) Perform tape casting on the aluminum nitride slurry, and obtain an aluminum nitride tape-cast blank after drying;

[0011] (3) Stack several layers of the aluminum nitride tape-cast blanks and then perform hot pressing to obtain an aluminum nitride hot-pressed blank;

[0012] (4) Perform cold isostatic pressing on the aluminum nitride hot-pressed blank to obtain an aluminum nitride blank sheet;

[0013] (5) Sinter the aluminum nitride blank sheet to obtain an aluminum nitride ceramic disc.

[0014] In the preparation method of the present invention, the aluminum nitride slurry obtained by mixing all raw materials is first tape-cast to obtain an aluminum nitride tape-cast blank with a smaller thickness, and then several layers of the aluminum nitride tape-cast blanks are stacked and hot-pressed, so as to increase the thickness and obtain an aluminum nitride hot-pressed blank with a target thickness. Finally, cold isostatic pressing and sintering are carried out in sequence, and an aluminum nitride ceramic disc with large size, ultra-thickness, and high density can be prepared.

[0015] As a preferred technical solution of the present invention, in step (1), the organic solvent includes at least two of ethanol, methyl ethyl ketone, isopropyl alcohol, or xylene, the dispersant includes herring oil and / or polyethylene glycol oleate, the binder includes polyvinyl butyral and / or polymethacrylate, and the sintering aid includes at least one of Y2O3, MgO, YF3, or CaO.

[0016] Preferably, in step (1), by mass percentage, the content of the organic solvent in the aluminum nitride slurry is 30-50 wt%, such as 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt% etc., the content of the dispersant is 1-5 wt%, such as 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt% etc., the content of the binder is 6-15 wt%, such as 6 wt%, 8 wt%, 10 wt%, 11 wt%, 13 wt%, or 15 wt% etc., the content of the sintering aid is 2-8 wt%, such as 2 wt%, 4 wt%, 6 wt%, or 8 wt% etc., and the rest is aluminum nitride.

[0017] The mixing in step (1) is carried out by using a jar mill with a powder mixing barrel.

[0018] Preferably, the rotation speed of the mixing is 200 - 300 r / min, such as 200 r / min, 210 r / min, 230 r / min, 250 r / min, 270 r / min, 280 r / min or 300 r / min, etc.

[0019] Preferably, the mixing time is 15 - 20 h, such as 15 h, 16 h, 17 h, 18 h, 19 h or 20 h, etc.

[0020] As a preferred technical solution of the present invention, before the casting forming in step (2), it further includes: degassing the aluminum nitride slurry.

[0021] Preferably, the degassing is carried out in a degassing machine.

[0022] Preferably, the temperature of the degassing is 30 - 60 °C, such as 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C or 60 °C, etc.

[0023] Preferably, the time of the degassing is 3 - 6 h, such as 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h or 6 h, etc.

[0024] Preferably, through the degassing, the viscosity of the slurry is adjusted to 8000 - 12000 mPa·s, such as 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, 11000 mPa·s or 12000 mPa·s, etc.

[0025] As a preferred technical solution of the present invention, the casting forming in step (2) is carried out by a casting machine.

[0026] Preferably, the height of the doctor blade for the casting forming in step (2) is 0.5 - 1.5 mm, such as 0.5 mm, 0.7 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.3 mm or 1.5 mm, etc.

[0027] Preferably, the casting speed for the casting forming in step (2) is 0.05 - 0.2 m / min, such as 0.05 m / min, 0.08 m / min, 0.1 m / min, 0.12 m / min, 0.15 m / min, 0.18 m / min or 0.2 m / min, etc.

[0028] Preferably, the thickness of the aluminum nitride casting blank in step (2) is 0.5 - 1.2 mm, such as 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm or 1.2 mm, etc.

[0029] As a preferred technical solution of the present invention, before the hot pressing in step (3), it further includes: cutting a plurality of layers of the aluminum nitride tape casting blanks into circular aluminum nitride tape casting blanks with the same diameter by a slicing machine.

[0030] Preferably, the diameter of the circular aluminum nitride tape casting blank is 200 - 400 mm, such as 200 mm, 250 mm, 300 mm, 350 mm or 400 mm, etc.

[0031] As a preferred technical solution of the present invention, the hot pressing in step (3) is carried out by a hot press.

[0032] Preferably, the temperature of the hot pressing in step (3) is 100 - 150 °C, such as 100 °C, 110 °C, 120 °C, 130 °C, 140 °C or 150 °C, etc.

[0033] Preferably, the pressure of the hot pressing in step (3) is 20 - 30 MPa, such as 20 MPa, 23 MPa, 25 MPa, 27 MPa or 30 MPa, etc.

[0034] Preferably, the pressure holding time of the hot pressing in step (3) is 10 - 15 min, such as 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, etc.

[0035] Preferably, the thickness of the aluminum nitride hot - pressed blank in step (3) is 20 - 30 mm, such as 20 mm, 23 mm, 25 mm, 27 mm or 30 mm, etc.

[0036] As a preferred technical solution of the present invention, step (4) includes: putting the aluminum nitride hot - pressed blank into an aluminum foil bag, evacuating to a vacuum degree ≤ 0.1 Pa, and then putting the vacuum - packaged aluminum nitride hot - pressed blank into a cold isostatic pressing device.

[0037] Preferably, the pressure of the cold isostatic pressing in step (4) is 200 - 250 MPa, such as 200 MPa, 210 MPa, 220 MPa, 230 MPa, 240 MPa or 250 MPa, etc.

[0038] Preferably, the pressure holding time of the cold isostatic pressing in step (4) is 5 - 10 min, such as 5 min, 6 min, 7 min, 8 min, 9 min or 10 min, etc.

[0039] As a preferred technical solution of the present invention, after step (4) and before step (5), it further includes: degreasing the aluminum nitride blank sheet.

[0040] Preferably, the degreasing is carried out in a degreasing furnace.

[0041] Preferably, the temperature of the debinding is 500 - 600 °C, such as 500 °C, 510 °C, 530 °C, 550 °C, 570 °C, 580 °C or 600 °C, etc.

[0042] Preferably, the holding time of the debinding is 3 - 5 h, such as 3 h, 3.5 h, 4 h, 4.5 h or 5 h, etc.

[0043] As a preferred technical solution of the present invention, the sintering in step (5) is carried out in a vacuum sintering furnace.

[0044] Preferably, the sintering in step (5) is carried out in a nitrogen atmosphere.

[0045] Preferably, the sintering temperature in step (5) is 1750 - 1850 °C, such as 1750 °C, 1780 °C, 1800 °C, 1820 °C, 1840 °C or 1850 °C, etc.

[0046] Preferably, the holding time of the sintering in step (5) is 2 - 5 h, such as 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h or 5 h, etc.

[0047] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0048] (1) Put aluminum nitride powder, organic solvent, dispersant, binder, and sintering aid into a powder mixing barrel, place it on a pot mill, adjust the rotation speed to 200 - 300 r / min, and the time to 15 - 20 h. After mixing evenly, an aluminum nitride slurry is obtained;

[0049] Among them, the organic solvent includes at least two of ethanol, methyl ethyl ketone, isopropyl alcohol or xylene, the dispersant includes herring oil and / or polyethylene glycol oleate, the binder includes polyvinyl butyral and / or polymethacrylate, and the sintering aid includes at least one of Y2O3, MgO, YF3 or CaO;

[0050] By mass percentage, the content of the organic solvent in the aluminum nitride slurry is 30 - 50 wt%, the content of the dispersant is 1 - 5 wt%, the content of the binder is 6 - 15 wt%, the content of the sintering aid is 2 - 8 wt%, and the rest is aluminum nitride;

[0051] (2) Pour the aluminum nitride slurry into a defoaming machine, carry out defoaming at 30 - 60 °C for 3 - 6 h, adjust the viscosity of the slurry to 8000 - 12000 mPa·s, pour the defoamed slurry into a casting machine for casting forming, adjust the height of the doctor blade to 0.5 - 1.5 mm, adjust the casting speed to 0.05 - 0.2 m / min, and after drying, an aluminum nitride casting blank with a thickness of 0.5 - 1.2 mm is obtained;

[0052] (3) Cut several layers of the as-cast AlN blanks into circular as-cast AlN blanks with the same diameter using a slicing machine, control the diameter to be 200 - 400 mm, stack the several layers of as-cast AlN blanks obtained by cutting together, put them into a hot press for hot pressing, adjust the temperature to 100 - 150 °C, adjust the pressure to 20 - 30 MPa, adjust the holding pressure time to 10 - 15 min, and obtain an AlN hot-pressed blank with a thickness of 20 - 30 mm;

[0053] (4) Put the AlN hot-pressed blank into an aluminum foil bag and evacuate it, control the vacuum degree ≤ 0.1 Pa, then put the vacuum-packaged AlN hot-pressed blank into a cold isostatic pressing device for cold isostatic pressing, adjust the pressure to 200 - 250 MPa, adjust the holding pressure time to 5 - 10 min, and obtain an AlN blank sheet;

[0054] (5) Put the AlN blank sheet into a debinding furnace and carry out debinding at 500 - 600 °C for 3 - 5 h, then put the debound AlN blank sheet into a vacuum sintering furnace, introduce nitrogen, and carry out sintering at 1750 - 1850 °C for 2 - 5 h to obtain an AlN ceramic disc.

[0055] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0056] The preparation method of the present invention can break through the thickness limitation of simple tape casting through the cooperation of tape casting and hot pressing, and thus can prepare large-sized, ultra-thick, and high-density AlN ceramic discs with excellent thermal conductivity and flexural properties. Specific embodiments

[0057] To facilitate the understanding of the present invention, the following examples are listed. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0058] Example 1

[0059] This example provides a preparation method of an AlN ceramic disc, and the preparation method includes the following steps:

[0060] (1) Put aluminum nitride powder, an organic solvent, a dispersant, a binder, and a sintering aid into a powder mixing barrel, place it on a jar mill, adjust the rotation speed to 250 r / min, and the time to 18 h. After mixing evenly, obtain an aluminum nitride slurry;

[0061] Among them, the organic solvent is a mixed solvent of ethanol and methyl ethyl ketone with a mass ratio of 1:1, the dispersant is herring oil, the binder is polyvinyl butyral, and the sintering aid is Y2O3;

[0062] By mass percentage, the content of the organic solvent in the aluminum nitride slurry is 40 wt%, the content of the dispersant is 3 wt%, the content of the binder is 12 wt%, the content of the sintering aid is 5 wt%, and the rest is aluminum nitride;

[0063] (2) Pour the aluminum nitride slurry into a defoamer, carry out defoaming at 50 °C for 5 h, adjust the viscosity of the slurry to 10000 mPa·s, pour the defoamed slurry into a casting machine for tape casting, adjust the height of the doctor blade to 1.0 mm, adjust the casting speed to 0.1 m / min, and after drying, obtain an aluminum nitride tape-cast green body with a thickness of 0.9 mm;

[0064] (3) Respectively cut 30 pieces of the aluminum nitride tape-cast green bodies into circular aluminum nitride tape-cast green bodies with the same diameter by a slicing machine, control the diameter to be 200 mm, stack a number of layers of the cut aluminum nitride tape-cast green bodies together, put them into a hot press for hot pressing, adjust the temperature to 120 °C, adjust the pressure to 25 MPa, adjust the holding pressure time to 12 min, and obtain an aluminum nitride hot-pressed green body with a thickness of 25 mm;

[0065] (4) Put the aluminum nitride hot-pressed green body into an aluminum foil bag and evacuate it, control the vacuum degree ≤ 0.1 Pa, then put the vacuum-packaged aluminum nitride hot-pressed green body into a cold isostatic pressing equipment for cold isostatic pressing, adjust the pressure to 220 MPa, adjust the holding pressure time to 8 min, and obtain an aluminum nitride green body sheet;

[0066] (5) Put the aluminum nitride green body sheet into a debinding furnace, carry out debinding at 550 °C for 4 h, then put the debound aluminum nitride green body sheet into a vacuum sintering furnace, introduce nitrogen, and carry out sintering at 1800 °C for 3 h to obtain an aluminum nitride ceramic disc.

[0067] Example 2

[0068] This example provides a method for preparing an aluminum nitride ceramic disc, and the preparation method includes the following steps:

[0069] (1) Put aluminum nitride powder, an organic solvent, a dispersant, a binder, and a sintering aid into a powder mixing barrel, place it on a pot mill, adjust the rotation speed to 200 r / min, and the time to 20 h, and after mixing evenly, obtain an aluminum nitride slurry;

[0070] Among them, the organic solvent is a mixed solvent of methyl ethyl ketone and isopropyl alcohol with a mass ratio of 1:1, the dispersant is polyethylene glycol oleate, the binder is polymethacrylate, and the sintering aid is MgO;

[0071] By mass percentage, the content of the organic solvent in the aluminum nitride slurry is 30 wt%, the content of the dispersant is 5 wt%, the content of the binder is 15 wt%, the content of the sintering aid is 8 wt%, and the rest is aluminum nitride;

[0072] (2) Pour the aluminum nitride slurry into a defoaming machine, perform defoaming at 30 °C for 6 h, adjust the viscosity of the slurry to 8000 mPa·s, pour the defoamed slurry into a casting machine for tape casting, adjust the height of the doctor blade to 0.5 mm, adjust the casting speed to 0.05 m / min, and after drying, obtain an aluminum nitride tape-cast green body with a thickness of 0.5 mm;

[0073] (3) Respectively cut 50 pieces of the aluminum nitride tape-cast green bodies into circular aluminum nitride tape-cast green bodies with the same diameter by a slicing machine, control the diameter to be 300 mm, stack the obtained several layers of aluminum nitride tape-cast green bodies together, put them into a hot press for hot pressing, adjust the temperature to 100 °C, adjust the pressure to 20 MPa, adjust the pressure holding time to 15 min, and obtain an aluminum nitride hot-pressed green body with a thickness of 23 mm;

[0074] (4) Put the aluminum nitride hot-pressed green body into an aluminum foil bag and evacuate it, control the vacuum degree ≤ 0.1 Pa, then put the vacuum-packaged aluminum nitride hot-pressed green body into a cold isostatic pressing device for cold isostatic pressing, adjust the pressure to 200 MPa, adjust the pressure holding time to 10 min, and obtain an aluminum nitride green body sheet;

[0075] (5) Put the aluminum nitride green body sheet into a debinding furnace, perform debinding at 500 °C for 5 h, then put the debound aluminum nitride green body sheet into a vacuum sintering furnace, introduce nitrogen, and sinter at 1750 °C for 5 h to obtain an aluminum nitride ceramic disc.

[0076] Example 3

[0077] This example provides a method for preparing an aluminum nitride ceramic disc, and the preparation method includes the following steps:

[0078] (1) Put aluminum nitride powder, an organic solvent, a dispersant, a binder, and a sintering aid into a powder mixing barrel, place it on a jar mill, adjust the rotation speed to 300 r / min, and the time to 15 h, and after mixing evenly, obtain an aluminum nitride slurry;

[0079] Among them, the organic solvent is a mixed solvent of isopropyl alcohol and xylene with a mass ratio of 1:1, the dispersant is polyethylene glycol oleate, the binder is polymethacrylate, and the sintering aid is CaO;

[0080] By mass percentage, the content of the organic solvent in the aluminum nitride slurry is 50 wt%, the content of the dispersant is 1 wt%, the content of the binder is 6 wt%, the content of the sintering aid is 2 wt%, and the rest is aluminum nitride;

[0081] (2) Pour the aluminum nitride slurry into a degassing machine, degas it at 60 °C for 3 h, adjust the viscosity of the slurry to 12,000 mPa·s, pour the degassed slurry into a casting machine for tape casting, adjust the height of the doctor blade to 1.5 mm, adjust the casting speed to 0.2 m / min, and after drying, obtain an aluminum nitride tape-cast green body with a thickness of 1.2 mm;

[0082] (3) Respectively cut 20 pieces of the aluminum nitride tape-cast green bodies into circular aluminum nitride tape-cast green bodies with the same diameter by a slicing machine, control the diameter to be 400 mm, stack the obtained several layers of aluminum nitride tape-cast green bodies together, put them into a hot press for hot pressing, adjust the temperature to 150 °C, adjust the pressure to 30 MPa, adjust the pressure holding time to 10 min, and obtain an aluminum nitride hot-pressed green body with a thickness of 23 mm;

[0083] (4) Put the aluminum nitride hot-pressed green body into an aluminum foil bag and evacuate it, control the vacuum degree ≤ 0.1 Pa, then put the vacuum-packaged aluminum nitride hot-pressed green body into a cold isostatic pressing equipment for cold isostatic pressing, adjust the pressure to 250 MPa, adjust the pressure holding time to 5 min, and obtain an aluminum nitride green body sheet;

[0084] (5) Put the aluminum nitride green body sheet into a debinding furnace, carry out debinding at 600 °C for 3 h, then put the debound aluminum nitride green body sheet into a vacuum sintering furnace, introduce nitrogen, and sinter at 1850 °C for 2 h to obtain an aluminum nitride ceramic disc.

[0085] Example 4

[0086] This example provides a method for preparing an aluminum nitride ceramic disc. Compared with Example 1, the difference is only that: in step (2), the viscosity of the slurry is adjusted to 7000 mPa·s.

[0087] Example 5

[0088] This example provides a method for preparing an aluminum nitride ceramic disc. Compared with Example 1, the difference is only that: in step (2), the viscosity of the slurry is adjusted to 13,000 mPa·s.

[0089] Example 6

[0090] This example provides a method for preparing an aluminum nitride ceramic disc. Compared with Example 1, the difference is only that: in step (4), the pressure of cold isostatic pressing is 180 MPa.

[0091] Example 7

[0092] This example provides a method for preparing an aluminum nitride ceramic disc. Compared with Example 1, the difference is only that: in step (4), the pressure of cold isostatic pressing is 280 MPa.

[0093] Example 8

[0094] This example provides a method for preparing an aluminum nitride ceramic disk. Compared with Example 1, the only difference is that in step (5), the sintering temperature is 1700 °C.

[0095] Example 9

[0096] This example provides a method for preparing an aluminum nitride ceramic disk. Compared with Example 1, the only difference is that in step (5), the sintering temperature is 1900 °C.

[0097] Comparative Example 1

[0098] This comparative example provides a method for preparing an aluminum nitride ceramic disk. Compared with Example 1, the only difference is that cold isostatic pressing in step (4) is completely omitted, that is, the hot-pressed blank of aluminum nitride obtained in step (4) is directly put into a degreasing furnace for degreasing, and then sintered in a vacuum sintering furnace.

[0099] The aluminum nitride ceramic disks prepared in the above examples and comparative examples were respectively tested for density, thermal conductivity and flexural properties. The relevant test results are shown in Table 1.

[0100] Table 1

[0101] Project Density / % Thermal conductivity / W / (m·K) Flexural property / MPa Example 1 99.7％ 185 471 Example 2 99.6％ 158 420 Example 3 99.7％ 163 452 Example 4 99.2％ 154 359 Example 5 98.8％ 176 443 Example 6 99.4％ 159 384 Example 7 99.5％ 178 459 Example 8 99.1％ 154 358 Example 9 99.6％ 161 428 Comparative Example 1 98.1％ 142 283

[0102] In summary, the preparation method of the present invention can break through the thickness limitation of simple tape casting through the combination of tape casting and hot pressing, and then can prepare large-size, ultra-thick, and high-density aluminum nitride ceramic disks with excellent thermal conductivity and flexural properties. Among them, the density reaches 99.1-99.9%, the thermal conductivity ≥ 150 W / mK, and the flexural strength ≥ 300 MPa, meeting the use requirements.

[0103] The present invention uses the above examples to illustrate the detailed process equipment and process flow of the present invention, but the present invention is not limited to the above detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and public scope of the present invention.

Claims

1. A method for preparing an aluminum nitride ceramic disk, characterized in that: The preparation method comprises the following steps: (1) mixing aluminum nitride powder, an organic solvent, a dispersant, a binder, and a sintering aid to obtain an aluminum nitride slurry; (2) tape-casting the aluminum nitride slurry, and obtaining an aluminum nitride tape-cast blank after drying; (3) stacking a plurality of layers of the aluminum nitride tape-cast blanks and hot pressing them to obtain aluminum nitride hot-pressed blanks; (4) performing cold isostatic pressing on the aluminum nitride hot pressed blank to obtain an aluminum nitride blank sheet; (5) Sintering the aluminum nitride blank to obtain an aluminum nitride ceramic disk.

2. The preparation method according to claim 1, characterized in that: In step (1), the organic solvent comprises at least two of ethanol, butanone, isopropanol or xylene, the dispersant comprises herring oil and / or polyethylene glycol oleate, the binder comprises polyvinyl butyral and / or polymethacrylate, and the sintering aid comprises at least one of Y2O3, MgO, YF3 or CaO; Preferably, in step (1), the aluminum nitride slurry contains, by mass percentage, 30-50wt% organic solvent, 1-5wt% dispersant, 6-15wt% binder, 2-8wt% sintering aid, and the rest is aluminum nitride; Preferably, the mixing in step (1) is carried out using a pot mill with a powder mixing barrel; Preferably, the mixing speed is 200-300r / min; Preferably, the mixing time is 15-20 hours.

3. The preparation method according to claim 1 or 2, characterized in that: Before the tape casting in step (2), the method further includes: degassing the aluminum nitride slurry; Preferably, the degassing is carried out in a degassing machine; Preferably, the degassing temperature is 30-60°C; Preferably, the degassing time is 3-6h; Preferably, the viscosity of the slurry is adjusted to 8000-12000 mPa·s through the degassing.

4. The preparation method according to any one of claims 1 to 3, characterized in that The tape casting in step (2) is carried out using a tape casting machine; Preferably, the scraper height of the tape-casting in step (2) is 0.5-1.5 mm; Preferably, the casting speed of the tape casting in step (2) is 0.05-0.2 m / min; Preferably, the thickness of the aluminum nitride tape-cast blank in step (2) is 0.5-1.2 mm.

5. The preparation method according to any one of claims 1 to 4, characterized in that: Before the hot pressing in step (3), the method further includes: cutting the plurality of layers of the aluminum nitride tape-cast blanks into circular aluminum nitride tape-cast blanks of the same diameter by a slicer; Preferably, the diameter of the circular aluminum nitride casting blank is 200-400 mm.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The hot pressing in step (3) is performed using a hot press; Preferably, the temperature of the hot pressing in step (3) is 100-150°C; Preferably, the hot pressing pressure in step (3) is 20-30 MPa; Preferably, the holding time of the hot pressing in step (3) is 10-15 minutes; Preferably, the thickness of the aluminum nitride hot-pressed blank in step (3) is 20-30 mm.

7. The preparation method according to any one of claims 1 to 6, characterized in that: Step (4) comprises: placing the aluminum nitride hot-pressed blank into an aluminum foil bag and evacuating the bag, controlling the vacuum degree to be ≤0.1 Pa, and then placing the vacuum-packed aluminum nitride hot-pressed blank into a cold isostatic pressing device; Preferably, the pressure of the cold isostatic pressing in step (4) is 200-250 MPa; Preferably, the holding time of the cold isostatic pressing in step (4) is 5-10 minutes.

8. The preparation method according to any one of claims 1 to 7, characterized in that: After step (4) and before step (5), the method further includes: degreasing the aluminum nitride blank sheet; Preferably, the degreasing is carried out in a degreasing furnace; Preferably, the degreasing temperature is 500-600°C; Preferably, the degreasing insulation time is 3-5h.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The sintering in step (5) is carried out in a vacuum sintering furnace; Preferably, the sintering in step (5) is carried out under a nitrogen atmosphere; Preferably, the sintering temperature of step (5) is 1750-1850°C; Preferably, the sintering holding time in step (5) is 2-5 hours.

10. The preparation method according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: (1) putting aluminum nitride powder, organic solvent, dispersant, binder and sintering aid into a powder mixing barrel, placing the barrel on a pot mill, adjusting the speed to 200-300 r / min, the time to 15-20 h, and mixing evenly to obtain aluminum nitride slurry; Wherein, the organic solvent comprises at least two of ethanol, butanone, isopropanol or xylene, the dispersant comprises herring oil and / or polyethylene glycol oleate, the binder comprises polyvinyl butyral and / or polymethacrylate, and the sintering aid comprises at least one of Y2O3, MgO, YF3 or CaO; In terms of mass percentage, the aluminum nitride slurry contains 30-50wt% organic solvent, 1-5wt% dispersant, 6-15wt% binder, 2-8wt% sintering aid, and the rest is aluminum nitride; (2) pouring the aluminum nitride slurry into a degassing machine, degassing at 30-60° C. for 3-6 hours, adjusting the viscosity of the slurry to 8000-12000 mPa·s, pouring the degassing slurry into a tape casting machine for tape casting, adjusting the scraper height to 0.5-1.5 mm, adjusting the tape casting speed to 0.05-0.2 m / min, and drying to obtain an aluminum nitride tape casting blank with a thickness of 0.5-1.2 mm; (3) cutting the several layers of the aluminum nitride tape-cast blanks into circular aluminum nitride tape-cast blanks of the same diameter by a slicer, controlling the diameter to be 200-400 mm, stacking the several layers of the aluminum nitride tape-cast blanks obtained by cutting together, placing them in a hot press for hot pressing, adjusting the temperature to 100-150° C., adjusting the pressure to 20-30 MPa, and adjusting the holding time to 10-15 min, to obtain an aluminum nitride hot-pressed blank with a thickness of 20-30 mm; (4) placing the aluminum nitride hot-pressed blank into an aluminum foil bag and evacuating the bag, controlling the vacuum degree to be ≤0.1 Pa, and then placing the vacuum-packed aluminum nitride hot-pressed blank into a cold isostatic pressing device for cold isostatic pressing, adjusting the pressure to 200-250 MPa, and adjusting the holding time to 5-10 min to obtain an aluminum nitride blank sheet; (5) placing the aluminum nitride blank sheet into a degreasing furnace, degreasing the blank sheet at 500-600° C. for 3-5 hours, and then placing the degreased aluminum nitride blank sheet into a vacuum sintering furnace, introducing nitrogen, and sintering the blank sheet at 1750-1850° C. for 2-5 hours to obtain an aluminum nitride ceramic disk.