Aluminum nitride ceramic heating disc, preparation method and application thereof

Abstract

The application relates to an aluminum nitride ceramic heating disc and a preparation method and application thereof, and the preparation method comprises the following steps: mixing aluminum nitride powder and an additive, and then sequentially performing forming, hot-pressing sintering and densification to obtain the aluminum nitride ceramic heating disc. The application takes aluminum nitride powder as raw material, reduces production steps, reduces production cost and production difficulty, takes powder as raw material, is beneficial to improving the uniformity of the aluminum nitride ceramic, and is also beneficial to reducing the generation of internal microcracks of the ceramic. The application can effectively control the uniformity and thermal conductivity of the aluminum nitride ceramic heating disc by adding the additive. The application takes powder as raw material, prepares an aluminum nitride rough blank through hot-pressing sintering, and further improves the density of the aluminum nitride ceramic through densification. The aluminum nitride ceramic heating disc prepared by the application is uniform in microstructure and free of stratification, has high density, high strength and uniform thermal conductivity, and is not prone to cracking in the use process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor components, and relates to a ceramic heating disc and a preparation method and application thereof, in particular to an aluminum nitride ceramic heating disc and a preparation method and application thereof. BACKGROUND

[0002] The heating disc is a main component of the chemical vapor deposition equipment, and is used to carry the wafer and adjust the temperature of the wafer. The heating disc is internally provided with a heating element, and the temperature of the surface of the heating disc can be adjusted through the heating element. At present, the heating discs used in the semiconductor industry are mainly divided into two types: metal heating disc and ceramic heating disc. In the process of vapor deposition, specific gases are introduced into the equipment cavity, and the metal heating disc may react with these gases and affect the film coating on the wafer surface. The ceramic heating disc has stable chemical properties and is not easy to react with the gas, and also has excellent electrical properties and thermal conductivity, so its use in the chemical vapor deposition process is becoming more and more widespread.

[0003] At present, the main material of the ceramic heating disc is high-temperature ceramic material such as aluminum nitride, aluminum oxide or silicon carbide. In order to ensure the flatness and parallelism of the ceramic heating disc in the packaging and forming process, a multi-layer step-by-step hydraulic technology is usually used. However, the ceramic heating disc prepared by this method has low uniformity, density and strength, and problems such as uneven heating of the wafer and deformation of the disc body occur, which can easily lead to abnormal film coating.

[0004] CN110230043A discloses a chemical vapor deposition equipment, a ceramic heating disc and a preparation method of the ceramic heating disc. The first aluminum nitride ceramic substrate, the heating sheet, the second aluminum nitride ceramic substrate, the electrode plate and the third aluminum nitride ceramic substrate are sequentially bonded by ceramic slurry, and the heating disc is obtained by hot pressing and sintering. The ceramic heating disc prepared by the preparation method has good flatness and parallelism. However, the chemical composition, crystal phase composition and thermal and electrical properties of each layer of the aluminum nitride ceramic heating disc are different, which leads to low uniformity, density and strength of the aluminum nitride ceramic heating disc, and further causes problems such as uneven heating of the wafer and deformation of the disc body, and further causes abnormal film coating.

[0005] The existing technology has the problems of poor uniformity, low density and low strength of the aluminum nitride ceramic heating disc. Therefore, how to reduce the processing difficulty, simplify the processing technology, and prepare an aluminum nitride ceramic heating disc with uniform structure, high density and high strength has become a problem to be solved at present. SUMMARY

[0006] To solve the above technical problems, the application provides an aluminum nitride ceramic heating disc and a preparation method and application thereof. The application takes aluminum nitride powder as raw material, reduces production cost and production steps, and reduces production cost and production difficulty. Taking powder as raw material is conducive to improving the uniformity of aluminum nitride ceramic and reducing the generation of internal microcracks of the ceramic. The application can effectively regulate the uniformity and thermal conductivity of the aluminum nitride ceramic heating disc by adding an additive. The application takes powder as raw material, and first performs hot-pressing sintering and then densification. The aluminum nitride rough blank is prepared by hot-pressing sintering, and the density of the aluminum nitride ceramic is further improved by densification. The aluminum nitride ceramic heating disc prepared by the application has uniform microstructure without stratification, high density, high strength and uniform thermal conductivity, and is not easy to crack in use.

[0007] To achieve the above purpose, the application adopts the following technical solutions:

[0008] In a first aspect, the application provides a preparation method of an aluminum nitride ceramic heating disc, which comprises the following steps:

[0009] After mixing the aluminum nitride powder and the additive, the ceramic heating disc is obtained by sequentially performing forming, hot-pressing sintering and densification.

[0010] The application takes aluminum nitride powder as raw material, reduces production cost and production steps, and reduces production cost and production difficulty. Taking powder as raw material is conducive to improving the uniformity of aluminum nitride ceramic and reducing the generation of internal microcracks of the ceramic. The application can effectively regulate the uniformity and thermal conductivity of the aluminum nitride ceramic heating disc by adding an additive. The application takes powder as raw material, and first performs hot-pressing sintering and then densification. The aluminum nitride rough blank is prepared by hot-pressing sintering, and the density of the aluminum nitride ceramic is further improved by densification. The aluminum nitride ceramic heating disc prepared by the application has uniform microstructure without stratification, high density, high strength and uniform thermal conductivity, and is not easy to crack in use.

[0011] Preferably, the additive comprises ethanol.

[0012] Preferably, the mass fraction of the additive is 3%-10% based on 100% of the total mass of the aluminum nitride powder and the additive, for example, can be 3%, 5%, 7%, 8%, 9% or 10%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0013] Preferably, the mixing method comprises ball milling.

[0014] Preferably, the ball-to-material ratio of the ball milling is (2-5):1, for example, can be 2:1, 3:1, 4:1, 4.5:1 or 5:1, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0015] Preferably, the post-mixing, pre-shaping also includes granulation.

[0016] Preferably, the granulation includes spray granulation.

[0017] Preferably, the particle size D50 of the post-granulation is 50 μm-200 μm, for example, it can be 50 μm, 100 μm, 150 μm, 180 μm or 200 μm, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0018] Preferably, the shaping includes cold pressing.

[0019] Preferably, the pressure of the shaping is 20 MPa-50 MPa, for example, it can be 20 MPa, 30 MPa, 40 MPa, 45 MPa or 50 MPa, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0020] Preferably, the post-shaping, pre-hot pressing sintering also includes machining, to obtain a green body with a parallelism of 0.05 mm-0.2 mm, wherein the parallelism can be 0.05 mm, 0.1 mm, 0.15 mm, 0.18 mm or 0.2 mm, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0021] Preferably, the atmosphere of the hot pressing sintering is an inert gas atmosphere.

[0022] Preferably, the inert gas atmosphere includes a nitrogen gas atmosphere and / or an argon gas atmosphere.

[0023] Preferably, the hot pressing sintering includes one-stage sintering, two-stage sintering, three-stage sintering, four-stage sintering and five-stage sintering.

[0024] Preferably, the heating rate of the one-stage sintering is 1 ℃ / min-3 ℃ / min, for example, it can be 1 ℃ / min, 1.5 ℃ / min, 2 ℃ / min, 2.5 ℃ / min or 3 ℃ / min, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0025] Preferably, the holding temperature of the one-stage sintering is 100 ℃-250 ℃, for example, it can be 100 ℃, 150 ℃, 200 ℃, 220 ℃ or 250 ℃, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0026] Preferably, the holding time of the one-stage sintering is 1 h-3 h, for example, it can be 1 h, 1.5 h, 2 h, 2.5 h or 3 h, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0027] Preferably, the temperature increasing rate of the second-stage sintering is 0.5°C / min-3°C / min, for example, it can be 0.5°C / min, 1°C / min, 1.5°C / min, 2°C / min, 2.5°C / min or 3°C / min, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0028] Preferably, the holding temperature of the second-stage sintering is 400°C-600°C, for example, it can be 400°C, 450°C, 500°C, 550°C or 600°C, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0029] Preferably, the holding time of the second-stage sintering is 20h-30h, for example, it can be 20h, 22h, 24h, 26h, 28h or 30h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0030] Preferably, the temperature increasing rate of the third-stage sintering is 2°C / min-5°C / min, for example, it can be 2°C / min, 2.5°C / min, 3°C / min, 3.5°C / min, 4°C / min, 4.5°C / min or 5°C / min, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0031] Preferably, the holding temperature of the third-stage sintering is 900°C-1100°C, for example, it can be 900°C, 950°C, 1000°C, 1050°C or 1100°C, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0032] Preferably, the holding time of the third-stage sintering is 3h-5h, for example, it can be 3h, 3.5h, 4h, 4.5h, 4.8h or 5h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0033] Preferably, the third-stage sintering is started with pressure.

[0034] Preferably, the speed of the pressure is 7.5MPa / h-17.5MPa / h, for example, it can be 7.5MPa / h, 10MPa / h, 12.5MPa / h, 15MPa / h or 17.5MPa / h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0035] Preferably, the end pressure of the pressurization is 15 MPa - 35 MPa, for example, it can be 15 MPa, 18 MPa, 20 MPa, 25 MPa, 30 MPa or 35 MPa, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0036] Preferably, the temperature rising rate of the four-stage sintering is 2℃ / min - 5℃ / min, for example, it can be 2℃ / min, 2.5℃ / min, 3℃ / min, 3.5℃ / min, 4℃ / min or 5℃ / min, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0037] Preferably, the holding temperature of the four-stage sintering is 1300℃ - 1500℃, for example, it can be 1300℃, 1350℃, 1400℃, 1450℃ or 1500℃, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0038] Preferably, the holding time of the four-stage sintering is 3h - 5h, for example, it can be 3h, 3.5h, 4h, 4.5h, 4.8h or 5h, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0039] Preferably, the environmental pressure of the four-stage sintering is 15 MPa - 35 MPa, for example, it can be 15 MPa, 18 MPa, 20 MPa, 25 MPa, 30 MPa or 35 MPa, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0040] Preferably, the temperature rising rate of the five-stage sintering is 2℃ / min - 5℃ / min, for example, it can be 2℃ / min, 2.5℃ / min, 3℃ / min, 3.5℃ / min, 4℃ / min or 5℃ / min, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0041] Preferably, the holding temperature of the five-stage sintering is 1600℃ - 1750℃, for example, it can be 1600℃, 1650℃, 1700℃, 1720℃ or 1750℃, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0042] Preferably, the holding time of the five-stage sintering is 5h - 8h, for example, it can be 5h, 5.5h, 6h, 7h, 7.5h or 8h, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0043] Preferably, the ambient pressure of the five-stage sintering is 15-35 MPa, for example, it can be 15 MPa, 18 MPa, 20 MPa, 25 MPa, 30 MPa or 35 MPa, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0044] The present application improves the uniformity, thermal conductivity and density of aluminum nitride ceramic by five-stage sintering. Among them, the holding temperature and holding time of the first stage sintering are beneficial to remove water vapor in the raw material powder and prevent the aluminum nitride powder from being hydrolyzed at a higher temperature; the holding temperature and holding time of the second stage sintering are beneficial to remove organic matter in the additive and prevent the organic matter from remaining in the heating disc in the subsequent steps, affecting the thermal conductivity and strength of the heating disc; the holding temperature and holding time of the third stage sintering realize the pre-shrinkage of the heating disc, expel the gas in the raw material powder, and further improve the uniformity and density of the heating disc; the holding temperature and holding time of the fourth stage sintering improve the shrinkage rate of the heating disc and also prevent the shrinkage rate from being too fast due to too high temperature, affecting the density of the heating disc; the holding temperature and holding time of the fifth stage sintering provide a suitable temperature and time for the uniform growth of the crystal grains, which is beneficial to reduce the structural defects in the heating disc and improve the density and strength of the heating disc.

[0045] Preferably, after the hot-pressing sintering and before the densification, the shape is adjusted to obtain a green body without concave and uneven surface.

[0046] Preferably, the densification includes hot isostatic pressing sintering.

[0047] Preferably, the holding temperature of the densification is 1700-1850℃, for example, it can be 1700℃, 1750℃, 1800℃, 1820℃ or 1850℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0048] Preferably, the pressure of the densification is 120-160 MPa, for example, it can be 120 MPa, 130 MPa, 140 MPa, 150 MPa or 160 MPa, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0049] Preferably, the holding and pressure time of the densification is 5-8 h, for example, it can be 5 h, 5.5 h, 6 h, 7 h, 7.5 h or 8 h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0050] The present application prepares aluminum nitride ceramic by densification, and further improves the density and uniformity of the aluminum nitride ceramic by reasonably controlling the temperature and time of densification. Within the range of preferred densification temperature and sintering time, not only the aluminum nitride ceramic with uniform composition, high density and high strength can be obtained, but also the yield can be improved and the production cost can be reduced.

[0051] Preferably, after the densification, the outer shape is trimmed and the sleeve is welded in sequence to obtain the aluminum nitride ceramic heating disc.

[0052] As a preferred technical solution of the present application, the preparation method comprises the following steps:

[0053] (1) The aluminum nitride powder and the additive are mixed by ball milling in proportion to obtain a mixed slurry, wherein the ball-to-material ratio of ball milling is (2-5):1.

[0054] (2) The mixed slurry is granulated by a spray granulator to obtain spherical mixed powder with a particle size D50 of 50-200 μm.

[0055] (3) The spherical mixed powder and the heating wire are loaded into a mold for cold pressing forming under a pressure of 20-50 MPa to obtain a formed material, which is subjected to outer shape processing to obtain a green body with a parallelism of 0.05-0.2 mm.

[0056] (4) After the green body is placed in a hot pressing furnace, inert gas is injected to discharge the air in the furnace, and then hot pressing sintering is performed to obtain a green body after hot pressing sintering, wherein the heating rate of the first sintering is 1-3 ℃ / min, the holding temperature is 100-250 ℃, the holding time is 1-3 h, the heating rate of the second sintering is 0.5-3 ℃ / min, the holding temperature is 400-600 ℃, the holding time is 20-30 h, the heating rate of the third sintering is 2-5 ℃ / min, the holding temperature is 900-1100 ℃, the holding time is 3-5 h, and the pressure is applied at the beginning of the holding of the third sintering; the pressure application speed is 7.5-17.5 MPa / h, the final pressure is 15-35 MPa, the heating rate of the fourth sintering is 2-5 ℃ / min, the holding temperature is 1300-1500 ℃, the holding time is 3-5 h, the environmental pressure is 15-35 MPa, the heating rate of the fifth sintering is 2-5 ℃ / min, the holding temperature is 1600-1750 ℃, the holding time is 5-8 h, the environmental pressure is 15-35 MPa, and the heating is stopped after the holding time of the fifth sintering, and the pressure is maintained until 400 ℃, and then the pressure is released.

[0057] (5) the green body after hot-pressing sintering is subjected to shape adjustment, and then is transferred into a hot isostatic pressing furnace to be densified, to obtain a densified green body, wherein the holding temperature of the densification is 1700-1850 DEG C, the pressure is 120-160 MPa, and the holding and pressure-keeping time is 5-8 h.

[0058] (6) the densified green body is subjected to shape trimming and sleeve welding in sequence, to obtain the aluminum nitride ceramic heating disc.

[0059] In the second aspect, the application provides an aluminum nitride ceramic heating disc prepared by the preparation method in the first aspect.

[0060] In the third aspect, the application provides an application of the aluminum nitride ceramic heating disc in the second aspect, and the aluminum nitride ceramic heating disc is applied to chemical vapor deposition.

[0061] Compared with the prior art, the application has at least the following beneficial effects:

[0062] (1) The application uses aluminum nitride powder as raw material, reduces production steps, and reduces production cost and production difficulty, and using powder as raw material is beneficial to improve the uniformity of the aluminum nitride ceramic and is also beneficial to reduce the generation of internal micro-cracks of the ceramic.

[0063] (2) The application can effectively control the uniformity and thermal conductivity of the aluminum nitride ceramic heating disc by adding an additive.

[0064] (3) The application uses powder as raw material, first hot-presses and sinter, and then densifies, to prepare an aluminum nitride rough green body by hot-pressing sintering, and to further improve the density of the aluminum nitride ceramic by densification.

[0065] (4) The aluminum nitride ceramic heating disc prepared by the application has uniform microstructure without layering, high density, high strength, and uniform thermal conductivity, and is not easy to crack in use. DETAILED DESCRIPTION

[0066] In order to facilitate the understanding of the application, the application is illustrated by the following embodiments. It should be understood by those skilled in the art that the embodiments are only used to help understand the application, and should not be regarded as a specific limitation on the application.

[0067] Embodiment 1

[0068] The embodiment provides a preparation method of an aluminum nitride ceramic heating disc, and the preparation method comprises the following steps:

[0069] (1) ball-milling aluminum nitride powder and an additive to obtain mixed slurry, wherein the ball-to-material ratio of the ball-milling is 3:1, the mass ratio of the additive is 5%, and the additive is ethanol;

[0070] (2) the mixed slurry is granulated by a spray granulator to obtain spherical mixed powder with a particle size D50 of 100 μm;

[0071] (3) the spherical mixed powder and heating wires are loaded into a mold, cold pressing is performed at a pressure of 35 MPa to obtain a formed material, and contour processing is performed to obtain a green body with a parallelism of 0.1 mm between upper and lower surfaces;

[0072] (4) the green body is placed in a hot pressing furnace, nitrogen is injected to discharge air in the furnace, and hot pressing sintering is performed to obtain a sintered green body, wherein the heating rate of the first sintering is 2 ℃ / min, the holding temperature is 200 ℃, and the holding time is 2 h, the heating rate of the second sintering is 2 ℃ / min, the holding temperature is 500 ℃, and the holding time is 25 h, the heating rate of the third sintering is 3.5 ℃ / min, the holding temperature is 1000 ℃, and the holding time is 4 h, the third sintering is started with pressure, the pressure increasing rate is 10 MPa / h, the final pressure is 20 MPa, the heating rate of the fourth sintering is 3.5 ℃ / min, the holding temperature is 1400 ℃, the holding time is 4 h, and the environmental pressure is 20 MPa, the heating rate of the fifth sintering is 3.5 ℃ / min, the holding temperature is 1700 ℃, the holding time is 7.5 h, and the environmental pressure is 20 MPa, the heating of the fifth sintering is stopped after the holding time, the pressure is kept until 400 ℃, and then pressure relief is performed;

[0073] (5) the sintered green body is subjected to contour adjustment, and then is transferred into a hot isostatic pressing furnace for densification to obtain a densified green body, wherein the holding temperature of the densification is 1800 ℃, the pressure is 140 MPa, and the holding time is 6.5 h;

[0074] (6) the densified green body is subjected to contour trimming and sleeve welding in sequence to obtain the aluminum nitride ceramic heating disc.

[0075] Example 2

[0076] The present embodiment provides a preparation method of an aluminum nitride ceramic heating disc, which comprises the following steps:

[0077] (1) aluminum nitride powder and an additive are ball milled to obtain a mixed slurry, wherein the ball-to-material ratio of the ball milling is 2:1, the mass ratio of the additive is 10%, and the additive is ethanol;

[0078] (2) the mixed slurry is granulated by a spray granulator to obtain spherical mixed powder with a particle size D50 of 200 μm;

[0079] (3) the spherical mixed powder and heating wires are loaded into a mold, cold pressing is performed at a pressure of 50 MPa to obtain a formed material, and contour processing is performed to obtain a green body with a parallelism of 0.05 mm between upper and lower surfaces;

[0080] (4) After the green body is placed in the hot pressing furnace, argon is injected to discharge the air in the furnace, and then hot pressing sintering is performed to obtain a sintered green body, wherein the heating rate of the first sintering is 1℃ / min, the holding temperature is 100℃, and the holding time is 3h; the heating rate of the second sintering is 0.5℃ / min, the holding temperature is 400℃, and the holding time is 30h; the heating rate of the third sintering is 2℃ / min, the holding temperature is 900℃, and the holding time is 5h; the third sintering starts with pressure; the pressure rate is 7.5MPa / h, the final pressure is 15MPa; the heating rate of the fourth sintering is 2℃ / min, the holding temperature is 1300℃, and the holding time is 5h; the ambient pressure is 15MPa; the heating rate of the fifth sintering is 2℃ / min, the holding temperature is 1600℃, and the holding time is 8h; the ambient pressure is 15MPa; after the holding time of the fifth sintering ends, the heating is stopped, and the pressure is maintained until 400℃, and then the pressure is released;

[0081] (5) The sintered green body is subjected to shape adjustment, and then is transferred into a hot isostatic pressing furnace for densification to obtain a densified green body, wherein the holding temperature of the densification is 1700℃, the pressure is 160MPa, and the holding and pressure maintaining time is 8h;

[0082] (6) The densified green body is sequentially subjected to shape trimming and sleeve welding to obtain the aluminum nitride ceramic heating disc.

[0083] Example 3

[0084] The present embodiment provides a preparation method of an aluminum nitride ceramic heating disc, which comprises the following steps:

[0085] (1) Ball-milling aluminum nitride powder and an additive to obtain a mixed slurry, wherein the ball-to-material ratio of the ball-milling is 5:1, the mass ratio of the additive is 3%, and the additive is ethanol;

[0086] (2) The mixed slurry is granulated by a spray granulator to obtain spherical mixed powder with a particle size D50 of 50μm;

[0087] (3) The spherical mixed powder and heating wires are loaded into a mold for cold pressing forming under a pressure of 20MPa to obtain a formed material, which is subjected to shape processing to obtain a green body with a parallelism of 0.2mm between upper and lower surfaces;

[0088] (4) After the green body is put into the hot-pressing furnace, nitrogen is injected to discharge the air in the furnace, and then hot-pressing sintering is carried out, to obtain a hot-pressing sintered green body, wherein the heating rate of the first sintering is 3°C / min, the holding temperature is 250°C, and the holding time is 1 h; the heating rate of the second sintering is 3°C / min, the holding temperature is 600°C, and the holding time is 20 h; the heating rate of the third sintering is 5°C / min, the holding temperature is 1100°C, and the holding time is 3 h, and the third sintering starts with pressurization; the pressurization rate is 17.5 MPa / h, the final pressure is 35 MPa; the heating rate of the fourth sintering is 5°C / min, the holding temperature is 1500°C, the holding time is 3 h, and the environmental pressure is 35 MPa; the heating rate of the fifth sintering is 5°C / min, the holding temperature is 1750°C, the holding time is 5 h, and the environmental pressure is 35 MPa; after the holding time of the fifth sintering ends, heating is stopped, and the pressure is kept until 400°C, and then pressure relief is carried out;

[0089] (5) The hot-pressing sintered green body is subjected to shape adjustment, and then is transferred into a hot isostatic pressing furnace for densification, to obtain a densified green body, wherein the holding temperature of the densification is 1850°C, the pressure is 120 MPa, and the holding and pressurizing time is 5 h;

[0090] (6) The densified green body is subjected to shape trimming and sleeve welding in sequence, to obtain the aluminum nitride ceramic heating disc.

[0091] Example 4

[0092] The difference between this example and Example 1 is only that, in step (4), the temperature of the fourth sintering is 1250°C, and the rest is the same as in Example 1.

[0093] Example 5

[0094] The difference between this example and Example 1 is only that, in step (4), the temperature of the fourth sintering is 1550°C, and the rest is the same as in Example 1.

[0095] Example 6

[0096] The difference between this example and Example 1 is only that, in step (4), the temperature of the fifth sintering is 1550°C, and the rest is the same as in Example 1.

[0097] Example 7

[0098] The difference between this example and Example 1 is only that, in step (4), the temperature of the fifth sintering is 1800°C, and the rest is the same as in Example 1.

[0099] Example 8

[0100] The embodiment differs from example 1 only in that the holding temperature for densification in step (5) is 1650°C, and the rest is the same as example 1.

[0101] Example 9

[0102] The embodiment differs from example 1 only in that the holding temperature for densification in step (5) is 1900°C, and the rest is the same as example 1.

[0103] Example 10

[0104] The embodiment differs from example 1 only in that the holding time for densification in step (5) is 4.5h, and the rest is the same as example 1.

[0105] Example 11

[0106] The embodiment differs from example 1 only in that the holding time for densification in step (5) is 8.5h, and the rest is the same as example 1.

[0107] Example 12

[0108] The embodiment differs from example 1 only in that the four-stage sintering in step (4) is not performed, and the rest is the same as example 1.

[0109] Example 13

[0110] The embodiment differs from example 1 only in that the five-stage sintering in step (4) is not performed, and the rest is the same as example 1.

[0111] Comparative Example 1

[0112] The comparative example differs from example 1 only in that step (4) is not performed, and the rest is the same as example 1.

[0113] Comparative Example 2

[0114] The comparative example differs from example 1 only in that step (5) is not performed, and the rest is the same as example 1.

[0115] Comparative Example 3

[0116] The comparative example provides a preparation method of an aluminum nitride ceramic heating disc, which comprises the following steps:

[0117] (1) A first aluminum nitride ceramic substrate, a heating sheet, a second aluminum nitride ceramic substrate, an electrode plate and a third aluminum nitride ceramic substrate are sequentially bonded by an aluminum nitride ceramic slurry in the order from bottom to top to form a layer structure, thereby obtaining a green body;

[0118] (2) After the green body is placed in the hot-pressing furnace, inert gas is injected to discharge the air in the furnace, and then hot-pressing sintering is performed to obtain a sintered green body, wherein the heating rate of the first sintering is 2℃ / min, the holding temperature is 200℃, and the holding time is 2h; the heating rate of the second sintering is 2℃ / min, the holding temperature is 500℃, and the holding time is 25h; the heating rate of the third sintering is 3.5℃ / min, the holding temperature is 1000℃, and the holding time is 4h, and the third sintering starts with pressure; the pressure increasing rate is 10MPa / h, the final pressure is 20MPa; the heating rate of the fourth sintering is 3.5℃ / min, the holding temperature is 1400℃, the holding time is 4h, and the ambient pressure is 20MPa; the heating rate of the fifth sintering is 3.5℃ / min, the holding temperature is 1700℃, the holding time is 7.5h, and the ambient pressure is 20MPa; after the holding time of the fifth sintering ends, the heating is stopped, and the pressure is kept until 400℃, and then the pressure is released;

[0119] (3) The sintered green body is subjected to shape adjustment, and then is transferred into a hot isostatic pressing furnace for densification to obtain a densified green body, wherein the holding temperature of the densification is 1800℃, the pressure is 140MPa, and the holding time is 6.5h;

[0120] (4) The densified green body is subjected to shape trimming and sleeve welding in sequence to obtain the aluminum nitride ceramic heating disc.

[0121] Test method

[0122] The actual density of the aluminum nitride ceramic heating disc prepared in Examples 1-13 and Comparative Examples 1-3 is measured by the drainage method, the relative density is calculated by comparing with the theoretical density, and is recorded in Table 1.

[0123] Table 1

[0124] Density Example 1 99.6％ Example 2 99.5％ Example 3 99.3％ Example 4 98.7％ Example 5 98.9％ Example 6 99.0％ Example 7 98.5％ Example 8 99.1％ Example 9 98.7％ Example 10 98.5％ Example 11 99.0％ Example 12 98.3％ Example 13 97.6％ Comparative Example 1 73％ Comparative Example 2 92％ Comparative Example 3 93.5%, but with delamination, density not uniform

[0125] It can be seen from the test results that:

[0126] (1) It can be seen from Examples 1-13 and Comparative Examples 1-3 that the present application uses aluminum nitride powder as raw material, reduces the production steps, and reduces the production cost and difficulty, and uses powder as raw material, which is beneficial to improve the uniformity of the aluminum nitride ceramic and reduce the generation of internal micro-cracks of the ceramic. The present application can effectively control the uniformity and thermal conductivity of the aluminum nitride ceramic heating disc by adding additives. The present application uses powder as raw material, and first hot-presses and sintering and then densifies, and the aluminum nitride coarse green body is prepared by hot-pressing and sintering, and the density of the aluminum nitride ceramic is further improved by densification. The aluminum nitride ceramic heating disc prepared by the present application has uniform microstructure without stratification, high density, high strength and uniform thermal conductivity, and is not easy to crack during use.

[0127] (2) Through Example 1, Example 4-7 and Example 12-13, it can be seen that the present application further improves the density, strength and uniformity of the aluminum nitride ceramic heating disc by further limiting the temperature of four-stage sintering and five-stage sintering through hot-pressing sintering.

[0128] (3) Through Example 1 and Example 8-11, it can be seen that the present application further improves the density, strength and uniformity of the aluminum nitride ceramic heating disc by further regulating the holding temperature and holding time of densification.

[0129] In summary, the present application uses aluminum nitride powder as raw material, reduces the production steps, and reduces the production cost and difficulty, and uses powder as raw material, which is beneficial to improve the uniformity of aluminum nitride ceramic, and also beneficial to reduce the generation of internal micro-cracks of ceramic. The present application can effectively regulate the uniformity and thermal conductivity of the aluminum nitride ceramic heating disc by adding additives. The present application uses powder as raw material, hot-pressing sintering and then densification, prepares aluminum nitride rough blank through hot-pressing sintering, and further improves the density of aluminum nitride ceramic through densification. The aluminum nitride ceramic heating disc prepared by the present application has uniform microstructure without delamination, high density, high strength and uniform thermal conductivity, and is not easy to crack during use.

[0130] The applicant declares that the above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by any person skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method of producing an aluminum nitride ceramic heating disc, characterized by, The preparation method comprises the following steps: After mixing the aluminum nitride powder and the auxiliary agent, the aluminum nitride ceramic heating disc is obtained by sequentially performing forming, hot-pressing sintering and densification; The forming comprises cold-press forming; The pressure of the forming is 20-50 MPa; The atmosphere of the hot-pressing sintering is inert gas atmosphere; The auxiliary agent comprises ethanol; The hot-pressing sintering comprises one-stage sintering, two-stage sintering, three-stage sintering, four-stage sintering and five-stage sintering; The holding temperature of the one-stage sintering is 100-250 DEG C; The holding temperature of the two-stage sintering is 400-600 DEG C; The three-stage sintering is performed by pressurizing at the beginning of holding; The terminal pressure of the pressurizing is 15-35 MPa; The holding temperature of the three-stage sintering is 900-1100 DEG C; The holding temperature of the four-stage sintering is 1300-1500 DEG C; The holding temperature of the five-stage sintering is 1600-1750 DEG C; The ambient pressure of the four-stage sintering is 15-35 MPa; The ambient pressure of the five-stage sintering is 15-35 MPa; The densification comprises hot isostatic sintering; The holding temperature of the densification is 1700-1850 DEG C; The pressure of the densification is 120-160 MPa; The holding and pressurizing time of the densification is 5-8 h.

2. The production method according to claim 1, characterized by, The auxiliary agent accounts for 3-10% of the total mass of the aluminum nitride powder and the auxiliary agent.

3. The production method according to claim 1, characterized by, The mixing method comprises ball milling.

4. The method of claim 1, wherein, After the mixing, granulation is further performed before the forming.

5. The production method according to claim 4, characterized by, The particle size D50 of the granulation is 50-200 mu m.