Aluminum nitride-based solder paste and integrated soldering method

Abstract

The application discloses an aluminum nitride-based welding paste and an integrated welding method, and belongs to the technical field of ceramic welding. The paste comprises an inorganic functional phase, which comprises AlN powder, Y2O3, Sm2O3, SiO2, ZrO2, La2O3 and CeO2 in percentage by weight, wherein the purity of the AlN powder is greater than or equal to 99.9%, and the D50 is 1.2-1.8 mu m; and an organic carrier, which comprises ethyl cellulose, terpineol, a dispersing agent and a defoaming agent in percentage by weight; wherein the mass ratio of the inorganic functional phase to the organic carrier is 66-70:30-34. The aluminum nitride-based welding paste provided by the application takes AlN powder as a main phase, the thermal expansion of a welding layer is highly consistent with that of an aluminum nitride heater base material, the interface stress is greatly reduced, and the problems of easy generation of thermal stress, microcracks and delamination at the interface, which lead to unqualified helium leak detection and decreased bonding strength, are solved.

Description

Technical Field

[0001] This invention relates to the field of ceramic welding technology, and in particular to an aluminum nitride-based welding slurry and an integrated welding method. Background Technology

[0002] In existing technologies, such as using CaO-Al2O3 glass phase welding slurry to weld AlN ceramic heaters, the coefficient of thermal expansion of the slurry is generally high (e.g., 4.6–5.0 × 10⁻⁶). -6 / ℃), and AlN substrate (thermal expansion coefficient is 4.0~4.3×10). -6 The temperature difference (°C) is significant. During the heating, cooling, and thermal cycling processes of AlN ceramic heaters, thermal stress, microcracks, and delamination are easily generated at the weld interface, leading to helium leak failure, reduced bonding strength, and affecting the overall service life of the AlN ceramic heater. In addition, aluminum nitride ceramic heaters contain calcium and react in HF and plasma etching environments, which can easily lead to helium leak failure. In more severe cases, the weld layer may detach, which will also shorten the life of the welded heater. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an aluminum nitride-based welding slurry and an integrated welding method to improve the welding strength between the AlN ceramic shaft and the AlN ceramic disk and to extend the service life of the AlN ceramic heater.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0005] This invention provides an aluminum nitride-based welding slurry, the slurry comprising:

[0006] The inorganic functional phase comprises, by weight percentage: 70–80% AlN powder, 8–12% Y2O3, 1–4% Sm2O3, 3–7% SiO2, 2–6% ZrO2, 1–3% La2O3 and 0.5–1.5% CeO2, wherein the purity of the AlN powder is greater than or equal to 99.9% and the D50 is 1.2–1.8 μm;

[0007] The organic carrier comprises, by weight percentage: 3-5% ethyl cellulose, 93-97% terpineol, 0.6-1% dispersant and 0.1-0.3% defoamer;

[0008] The mass ratio of the inorganic functional phase to the organic carrier is 66–70:30–34.

[0009] Preferably, the method for preparing the slurry includes the following steps:

[0010] Step S1: Inorganic powder pretreatment

[0011] Weigh AlN powder, Y2O3, Sm2O3, SiO2, ZrO2, La2O3, and CeO2 according to the specified ratio, add anhydrous ethanol as the dispersion medium, place them in a ball mill jar, and wet ball mill at a speed of 140-160 rpm for 20-28 hours to make the powder uniformly mixed and the particle size refined to D50 of 1.2-1.8 μm;

[0012] Step S2: Powder drying and sieving

[0013] The ball-milled mixed powder was placed in an oven and dried at 100℃ for 22-26 hours to remove anhydrous ethanol. After drying, it was screened through a 190-210 mesh standard sieve to remove coarse particle impurities and was ready for use.

[0014] Step S3: Organic carrier preparation

[0015] Ethyl cellulose was added to terpineol according to the formula, and placed in a 70°C constant temperature water bath. The mixture was stirred until the ethyl cellulose was completely dissolved. Then, the dispersant and defoamer were added, and the mixture was stirred for another 30-40 minutes. The mixture was then filtered through a screen to remove insoluble matter, resulting in a clear and transparent organic carrier.

[0016] Step S4: Slurry mixing and dispersion

[0017] The dried and sieved inorganic powder is slowly added to the organic carrier while stirring. After mixing evenly, it is transferred to a planetary ball mill and ball-milled at a speed of 110-130 rpm for 10-12 hours to ensure that the inorganic powder is evenly dispersed in the organic carrier.

[0018] Step S5: Viscosity Adjustment and Defoaming

[0019] The viscosity of the slurry was tested using a rotational viscometer. If the viscosity was not within the range of 15,000 to 25,000 cP, it was adjusted to this range by adding terpineol or inorganic powder. Then, the slurry was placed in a vacuum degassing machine and degassed at a pressure of -0.095 MPa for at least 30 minutes to remove air bubbles from the slurry and obtain the finished bonding slurry.

[0020] Another aspect of the present invention discloses an integrated welding method for welding an AlN ceramic shaft and an AlN ceramic disk, the welding method comprising the following steps:

[0021] Step S1: Substrate Pretreatment

[0022] Select the AlN ceramic shaft and AlN ceramic disk to be welded, and use a diamond grinding wheel to grind the welding surfaces of the two to make the surface roughness Ra less than or equal to 0.1μm. Then, put the finely ground substrate into an acetone solution for ultrasonic cleaning to remove surface oil and impurities. After taking it out, dry it in an oven for later use.

[0023] Step S2: Slurry Coating

[0024] The prepared bonding paste was uniformly coated on the bonding surface of the AlN ceramic disk using screen printing. The coating thickness was controlled at 80-100 μm. After coating, the paste was pre-dried in an oven at 75-85℃ for 30-35 min to remove some of the organic carrier in the paste.

[0025] Step S3: Bonding and loading into the oven

[0026] Align the AlN ceramic shaft with the slurry-coated disc coaxially, apply a pressure of 0.08 to 0.1 MPa to make them fit tightly together, then place them in an AlN crucible and send them together into the sintering furnace.

[0027] Step S4: Sintering

[0028] High-purity nitrogen gas was introduced into the sintering furnace, with the nitrogen flow rate controlled at 50 mL / min. The following sintering curve was used:

[0029] From room temperature to 250℃: the heating rate is 0.5~1.5℃ / min, and the temperature is held for 50~70min to slowly remove the organic carrier from the slurry;

[0030] 250℃ to 900℃: The heating rate is 1 to 3℃ / min to further remove residual organic carriers and at the same time soften the sintering aid.

[0031] 900℃ to 1600℃: heating rate is 1~2℃ / min, holding temperature for 180~220min, so that the inorganic powder can be fully melted and reacted to form a dense welding layer;

[0032] 1600℃ to 1000℃: cooling rate is 2~3℃ / min;

[0033] From 1000℃ to room temperature: allow natural furnace cooling to avoid thermal stress caused by excessively rapid cooling;

[0034] Step S5: Post-processing and inspection

[0035] After sintering, the sample is removed, and the weld seam is gently ground with a diamond grinding wheel to remove surface overflow. Then, the sample is subjected to performance testing.

[0036] The above technical solution has the following beneficial effects:

[0037] This application introduces AlN powder to achieve a high degree of matching between the thermal expansion coefficient of the weld layer and the AlN substrate (heater nitride ceramic shaft and ceramic disk) to be welded, thus eliminating Ca impurity contamination from the source. It utilizes the sintering aid effect of rare earth oxides to optimize sintering performance and broaden the process window. The high thermal conductivity of AlN enhances the thermal conductivity of the weld layer and improves the temperature field uniformity of the heater. The added inert components do not participate in the reaction or affect the bonding effect; they serve only as filler components in the system. Ultimately, this results in a weld paste that is impurity-free, high-strength, highly airtight, and stable at high temperatures, meeting the requirements of ceramic heaters in high-end semiconductor general-purpose processes.

[0038] The aluminum nitride-based welding slurry of this application uses AlN powder as the main phase. The thermal expansion of the welding layer is highly consistent with that of the AlN heater substrate, which greatly reduces the interfacial stress and solves the problem that the interface is prone to thermal stress, microcracks, and delamination, which leads to failure of helium leak detection and reduced bonding strength. Detailed Implementation

[0039] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] Example 1

[0041] An aluminum nitride-based welding slurry, specifically comprising:

[0042] The inorganic functional phase comprises, by weight percentage: 70–80% AlN powder, 8–12% Y2O3, 1–4% Sm2O3, 3–7% SiO2, 2–6% ZrO2, 1–3% La2O3 and 0.5–1.5% CeO2, wherein the purity of the AlN powder is greater than or equal to 99.9% and the D50 is 1.2–1.8 μm;

[0043] Specifically, the sum of the weight percentages of AlN powder, Y2O3, Sm2O3, SiO2, ZrO2, La2O3, and CeO2 is 100%. By weight percentage, the inorganic functional phase may include: 75% AlN powder, 10% Y2O3, 3% Sm2O3, 5% SiO2, 4% ZrO2, 2% La2O3, and 1% CeO2. The purity of the AlN powder is greater than or equal to 99.9%, specifically 99.9% or 99.99%, and the D50 is 1.2–1.8 μm, specifically 1.5 μm.

[0044] The organic carrier comprises, by weight percentage: 3-5% ethyl cellulose, 93-97% terpineol, 0.6-1% dispersant and 0.1-0.3% defoamer;

[0045] Specifically, the total weight percentage of ethyl cellulose, terpineol, dispersant, and defoamer is 100%. By weight percentage, the organic carrier may include: 4% ethyl cellulose, 95% terpineol, 0.8% dispersant, and 0.2% defoamer. The dispersant may be BYK-110 dispersant.

[0046] The mass ratio of the inorganic functional phase to the organic support is 66-70:30-34. Specifically, the mass percentage of the inorganic functional phase is 66-70%, the mass percentage of the organic support is 30-34%, and the sum of the mass percentages of the inorganic functional phase and the organic support is 100%. For example, the mass ratio of the inorganic functional phase to the organic support can be 68:32 or 70:30.

[0047] In existing technologies, ceramic heaters welded using CaO-Al2O3 glass phase welding slurries generally have a high coefficient of thermal expansion (e.g., 4.6–5.0 × 10⁻⁶). -6 / ℃), and AlN substrate (thermal expansion coefficient is 4.0~4.3×10). -6 The temperature difference (°C) is significant. During heating, cooling, and thermal cycling, the weld interface is prone to thermal stress, microcracks, and delamination, leading to helium leak detection failure and decreased bond strength.

[0048] The aluminum nitride-based welding slurry of the present invention uses AlN powder as the main phase. The thermal expansion of the welding layer is highly consistent with that of the AlN ceramic heater base material, which greatly reduces the interfacial stress and solves the problems of easy generation of thermal stress, microcracks and delamination at the interface, which leads to failure of helium leak detection and reduced bonding strength.

[0049] Furthermore, existing ceramic heaters welded using CaO-Al2O3 glass phase welding paste will react in HF and plasma etching environments due to the presence of calcium, which can easily lead to helium leakage failure. In more severe cases, it can cause the weld layer to fall off, significantly shortening the lifespan of the welded heater.

[0050] This application uses high-purity AlN powder as the main phase of the welding layer, combined with rare earth oxides (Y2O3, Sm2O3) as sintering aids, and a small amount of SiO2 to lower the sintering temperature. At the same time, trace amounts of inert components (ZrO2, La2O3, CeO2) that do not affect the bonding performance are added to construct an inorganic functional phase without CaO. Combined with an organic carrier composed of ethyl cellulose and terpineol, a uniform and stable bonding slurry is prepared through processes such as mixing, ball milling, and degassing.

[0051] By introducing AlN powder, the thermal expansion coefficient of the weld layer is highly matched with that of the AlN substrate (heater nitride ceramic shaft and ceramic disk) to be welded, eliminating Ca impurity contamination from the source. The sintering performance is optimized and the process window is broadened by utilizing the sintering aid effect of rare earth oxides. The high thermal conductivity of AlN is used to improve the thermal conductivity of the weld layer and improve the temperature field uniformity of the heater. The added inert components do not participate in the reaction and do not affect the bonding effect, but only serve as filler components in the system. Finally, a weld structure with no impurities, high strength, high airtightness, and high temperature stability is obtained, which is suitable for the ceramic heater requirements of high-end semiconductor general process.

[0052] This application addresses the shortcomings of existing CaO-Al2O3 systems by controlling the particle size and purity of AlN powder, and by combining it with appropriate proportions of sintering aids and inert interfering components to ensure the coatability and sinterability of the slurry. At the same time, it achieves thermodynamic matching and strong interfacial bonding between the weld layer and the AlN substrate.

[0053] Example 2

[0054] The preparation method of the above-mentioned aluminum nitride-based welding slurry specifically includes the following steps:

[0055] Step S1: Inorganic powder pretreatment

[0056] Weigh AlN powder, Y2O3, Sm2O3, SiO2, ZrO2, La2O3, and CeO2 according to the specified ratio, add anhydrous ethanol as the dispersion medium, place them in a ball mill jar, and wet ball mill at a speed of 140-160 rpm for 20-28 hours to make the powder uniformly mixed and the particle size refined to D50 of 1.2-1.8 μm;

[0057] Specifically, weigh AlN powder, Y2O3, Sm2O3, SiO2, ZrO2, La2O3, and CeO2 and add them to a ball mill jar. Then add anhydrous ethanol as a dispersion medium and wet ball mill at 140 rpm or 160 rpm for 20 h or 28 h, or at 150 rpm for 24 h, to make the powder uniformly mixed and the particle size refined to a D50 in the range of 1.2 to 1.8 μm.

[0058] Step S2: Powder drying and sieving

[0059] The ball-milled mixed powder was placed in an oven and dried at 100℃ for 22-26 hours to remove anhydrous ethanol. After drying, it was screened through a 190-210 mesh standard sieve to remove coarse particle impurities and was ready for use.

[0060] Specifically, the ball-milled mixed powder is placed in an oven and dried at 100°C for 22 hours, 26 hours, or 24 hours to remove anhydrous ethanol. After drying, it is screened through a 190 or 210 mesh standard sieve, or a 200 mesh standard sieve, to remove coarse particle impurities and is ready for use.

[0061] Step S3: Organic carrier preparation

[0062] According to the formula, ethyl cellulose is added to terpineol and placed in a 70°C constant temperature water bath. The mixture is stirred until the ethyl cellulose is completely dissolved. Then, a dispersant and an antifoaming agent are added, and stirring is continued for 30-40 minutes. The mixture is then filtered to remove insoluble matter, resulting in a clear and transparent organic carrier. Specifically, according to the mass percentage ratio of ethyl cellulose and terpineol, the two are placed in a 70°C constant temperature water bath and completely dissolved and mixed. Then, a dispersant and an antifoaming agent are added, and stirring is continued for 30 or 40 minutes. The mixture is then filtered to obtain the organic carrier.

[0063] Step S4: Slurry mixing and dispersion

[0064] The dried and sieved inorganic powder is slowly added to the organic carrier while stirring. After mixing evenly, it is transferred to a planetary ball mill and ball-milled at a speed of 110-130 rpm for 10-12 hours to ensure that the inorganic powder is evenly dispersed in the organic carrier.

[0065] Specifically, the powder is slowly added to the organic carrier while stirring. After mixing evenly, it is transferred to a planetary ball mill and ball-milled at 110 rpm or 130 rpm for 10 h or 12 h to ensure that the inorganic powder is evenly dispersed in the organic carrier.

[0066] Step S5: Viscosity Adjustment and Defoaming

[0067] The viscosity of the slurry was tested using a rotational viscometer (25°C). If the viscosity was not within the range of 15,000 to 25,000 cP, it was adjusted to this range by adding terpineol or inorganic powder. Then the slurry was placed in a vacuum degassing machine and degassed at a pressure of -0.095 MPa for at least 30 minutes to remove air bubbles from the slurry and obtain the finished bonding slurry.

[0068] Specifically, the viscosity of the slurry is tested using a rotational viscometer. The viscosity of the slurry is required to be in the range of 15,000 to 25,000 cP. If it is not in this range, the viscosity can be reduced by adding terpineol or adjusted to this range by adding inorganic powder (such as AlN powder). Then, the slurry is placed in a vacuum degassing machine and degassed at a pressure of -0.095 MPa for 30 or 40 minutes to remove air bubbles from the slurry and obtain the finished bonding slurry.

[0069] Example 3

[0070] An integrated welding method was used to weld an AlN ceramic shaft and an AlN ceramic disk (coefficient of thermal expansion 4.2 × 10⁻⁶) using the aluminum nitride-based welding slurry prepared above. -6 (temperature / ℃, thermal conductivity 180W / m·K), the welding method specifically includes the following steps:

[0071] Step S1: Substrate Pretreatment

[0072] Select the AlN ceramic shaft and AlN ceramic disk to be welded, and finely grind the welding surfaces of the two with a diamond wheel. The diamond wheel can be a 1000-grit diamond wheel, so that the surface roughness Ra is less than or equal to 0.1μm. The specific surface roughness Ra value can be 0.1μm. Then, put the finely ground substrate into an acetone solution for ultrasonic cleaning for 15-20 minutes to remove surface oil and impurities. After taking it out, dry it in an oven for 20-40 minutes for later use.

[0073] Step S2: Slurry Coating

[0074] The prepared bonding paste is uniformly coated onto the bonding surface of the AlN ceramic disk using screen printing. The coating thickness is controlled at 80–100 μm. After coating, it is pre-dried in an oven at 75–85°C for 30–35 min to remove some of the organic carrier in the paste. Specifically, the prepared aluminum nitride-based welding paste is uniformly coated onto the bonding surface of the AlN ceramic disk using screen printing. The coating thickness can be 80 μm, 100 μm, or 90 μm. After coating, it is pre-dried in an oven at 75°C or 85°C for 30 or 35 min to remove some of the organic carrier in the paste.

[0075] Step S3: Bonding and loading into the oven

[0076] AlN ceramic shafts are coaxially aligned with AlN ceramic disks coated with slurry, and a pressure of 0.08–0.1 MPa is applied to ensure tight adhesion between the two. Then, they are placed in an AlN crucible and sent together into a sintering furnace. Specifically, AlN ceramic shafts are coaxially aligned with AlN ceramic disks coated with slurry, and a pressure of 0.08 MPa or 0.1 MPa is applied from the axial direction of the AlN ceramic shaft to the AlN ceramic disk. Then, they are sent together into a sintering furnace for sintering. After the slurry is sintered and cured, the AlN ceramic shafts and AlN ceramic disks are welded together.

[0077] Step S4: Sintering

[0078] High-purity nitrogen gas (purity greater than or equal to 99.999%) was introduced into the sintering furnace, and the nitrogen flow rate was controlled at 50 mL / min. The following sintering curve was used:

[0079] From room temperature to 250℃: the heating rate is 0.5~1.5℃ / min, the holding time is 50~70min, and the organic carrier in the slurry is slowly discharged; specifically, when heating from room temperature to 250℃ in the sintering furnace, the heating rate is 0.5℃ / min or 1.5℃ / min, and the holding time at 250℃ is 50min or 70min, and the organic carrier in the slurry is slowly discharged. Alternatively, the temperature in the sintering furnace can be raised to 250℃ at a heating rate of 1℃ / min, and the holding time at 250℃ is 60min.

[0080] 250℃ to 900℃: The heating rate is 1 to 3℃ / min to further remove residual organic carriers and soften the sintering aid. Specifically, when heating from 250℃ to 900℃ in the sintering furnace, the heating rate is 1℃ / min or 3℃ / min to further remove residual organic carriers and soften the sintering aid. Alternatively, the temperature in the sintering furnace can be raised from 250℃ to 900℃ at a heating rate of 2℃ / min.

[0081] From 900℃ to 1600℃: the heating rate is 1-2℃ / min, and the holding time is 180-220min, so that the inorganic powder can be fully melted and reacted to form a dense weld layer. Specifically, when heating from 900℃ to 1600℃ in the sintering furnace, the heating rate is 1℃ / min or 2℃ / min, and the holding time at 1600℃ is 180min or 220min, so that the inorganic powder can be fully melted and reacted to form a dense weld layer (ZrO2, La2O3, and CeO2 do not participate in the reaction, but are uniformly dispersed in the weld layer and do not affect the density of the structure). Alternatively, the temperature in the sintering furnace can be raised from 900℃ to 1600℃ at a heating rate of 1.5℃ / min, and the holding time at 1600℃ is 200min.

[0082] 1600℃ to 1000℃: The cooling rate is 2 to 3℃ / min. Specifically, after the dense weld layer is formed, the temperature is cooled down from 1600℃ to 1000℃, and the cooling rate is 2℃ / min or 3℃ / min.

[0083] From 1000℃ to room temperature: allow the furnace to cool naturally to avoid thermal stress caused by rapid cooling. Complete the welding process after the temperature drops to room temperature.

[0084] Step S5: Post-processing and inspection

[0085] After sintering, the sample is removed, and the weld seam is gently ground with a diamond grinding wheel to remove surface overflow. Then, the sample is subjected to performance testing.

[0086] The test results are as follows:

[0087] The performance indicators of the welded samples prepared in this embodiment were tested and are as follows:

[0088] Thermal expansion coefficient of weld layer: 4.2 × 10⁻⁶ -6 / ℃, perfectly matched with AlN substrate;

[0089] The bond strength (three-point bending test) is 106 MPa;

[0090] The helium leak detection rate is: 3.9 × 10⁻⁶ -10 Pa·m³ / s;

[0091] The thermal conductivity of the weld layer is 70 W / m·K;

[0092] Thermal cycling test (-40→450℃, 100 cycles): No cracks, no delamination, and no change in airtightness.

[0093] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. An aluminum nitride-based welding slurry, characterized in that, The slurry includes: The inorganic functional phase comprises, by weight percentage: 70–80% AlN powder, 8–12% Y2O3, 1–4% Sm2O3, 3–7% SiO2, 2–6% ZrO2, 1–3% La2O3 and 0.5–1.5% CeO2, wherein the purity of the AlN powder is greater than or equal to 99.9% and the D50 is 1.2–1.8 μm; The organic carrier comprises, by weight percentage: 3-5% ethyl cellulose, 93-97% terpineol, 0.6-1% dispersant and 0.1-0.3% defoamer; The mass ratio of the inorganic functional phase to the organic carrier is 66–70:30–34.

2. The aluminum nitride-based welding slurry according to claim 1, characterized in that, The method for preparing the slurry includes the following steps: Step S1: Inorganic powder pretreatment Weigh AlN powder, Y2O3, Sm2O3, SiO2, ZrO2, La2O3, and CeO2 according to the specified ratio, add anhydrous ethanol as the dispersion medium, place them in a ball mill jar, and wet ball mill at a speed of 140-160 rpm for 20-28 hours to make the powder uniformly mixed and the particle size refined to D50 of 1.2-1.8 μm; Step S2: Powder drying and sieving The ball-milled mixed powder was placed in an oven and dried at 100℃ for 22-26 hours to remove anhydrous ethanol. After drying, it was screened through a 190-210 mesh standard sieve to remove coarse particle impurities and was ready for use. Step S3: Organic carrier preparation Ethyl cellulose was added to terpineol according to the formula, and placed in a 70°C constant temperature water bath. The mixture was stirred until the ethyl cellulose was completely dissolved. Then, the dispersant and defoamer were added, and the mixture was stirred for another 30-40 minutes. The mixture was then filtered through a screen to remove insoluble matter, resulting in a clear and transparent organic carrier. Step S4: Slurry mixing and dispersion The dried and sieved inorganic powder is slowly added to the organic carrier while stirring. After mixing evenly, it is transferred to a planetary ball mill and ball-milled at a speed of 110-130 rpm for 10-12 hours to ensure that the inorganic powder is evenly dispersed in the organic carrier. Step S5: Viscosity Adjustment and Defoaming The viscosity of the slurry was tested using a rotational viscometer. If the viscosity was not within the range of 15,000 to 25,000 cP, it was adjusted to this range by adding terpineol or inorganic powder. Then, the slurry was placed in a vacuum degassing machine and degassed at a pressure of -0.095 MPa for at least 30 minutes to remove air bubbles from the slurry and obtain the finished bonding slurry.

3. An integrated welding method for welding an AlN ceramic shaft and an AlN ceramic disk, characterized in that, The welding method includes the following steps: Step S1: Substrate Pretreatment Select the AlN ceramic shaft and AlN ceramic disk to be welded, and use a diamond grinding wheel to grind the welding surfaces of the two to make the surface roughness Ra less than or equal to 0.1μm. Then, put the finely ground substrate into an acetone solution for ultrasonic cleaning to remove surface oil and impurities. After taking it out, dry it in an oven for later use. Step S2: Slurry Coating The prepared bonding paste was uniformly coated on the bonding surface of the AlN ceramic disk using screen printing. The coating thickness was controlled at 80-100 μm. After coating, the paste was pre-dried in an oven at 75-85℃ for 30-35 min to remove some of the organic carrier in the paste. Step S3: Bonding and loading into the oven Align the AlN ceramic shaft with the slurry-coated disc coaxially, apply a pressure of 0.08 to 0.1 MPa to make them fit tightly together, then place them in an AlN crucible and send them together into the sintering furnace. Step S4: Sintering High-purity nitrogen gas was introduced into the sintering furnace, with the nitrogen flow rate controlled at 50 mL / min. The following sintering curve was used: From room temperature to 250℃: the heating rate is 0.5~1.5℃ / min, and the temperature is held for 50~70min to slowly remove the organic carrier from the slurry; 250℃ to 900℃: The heating rate is 1 to 3℃ / min to further remove residual organic carriers and at the same time soften the sintering aid. 900℃ to 1600℃: heating rate is 1~2℃ / min, holding temperature for 180~220min, so that the inorganic powder can be fully melted and reacted to form a dense welding layer; 1600℃ to 1000℃: cooling rate is 2~3℃ / min; From 1000℃ to room temperature: allow natural furnace cooling to avoid thermal stress caused by excessively rapid cooling; Step S5: Post-processing and inspection After sintering, the sample is removed, and the weld seam is gently ground with a diamond grinding wheel to remove surface overflow. Then, the sample is subjected to performance testing.