A method of welding an aluminum nitride heater support to a disk

Abstract

The application belongs to the technical field of ceramic welding and relates to a welding method for an aluminum nitride heater support body and a disc body, which comprises the following steps: (1) ball-milling aluminum nitride powder, a sintering aid, a binder, a dispersing agent and a solvent to obtain a mixed slurry, and then performing flow casting on the mixed slurry to obtain a flow-cast sheet; (2) placing the flow-cast sheet obtained in step (1) between a welding surface of a pretreated disc body and a welding surface of a support body, fixing the flow-cast sheet and then performing pressureless welding to complete the welding of the aluminum nitride heater support body and the disc body; the flow-cast sheet in step (2) comprises two outer flow-cast sheets and a transition layer flow-cast sheet arranged between the two outer flow-cast sheets, and the sintering aid content of the outer flow-cast sheets is greater than that of the transition layer flow-cast sheet. The welding method can avoid welding defects, welding cracking and failure, and effectively weld the support body and the disc body.

Description

Technical Field

[0001] This invention belongs to the field of ceramic welding technology and relates to a welding method for an aluminum nitride heater support and a disk. Background Technology

[0002] The stringent heating requirements of high-end semiconductor manufacturing, the inherent limitations of traditional heating solutions, and the superior properties of aluminum nitride (Anitride) materials have collectively propelled Anitride heaters to become a core and critical component. High-quality ceramic bonding seals have been applied to ceramic-packaged devices such as microelectromechanical systems (MEMS), microwave devices, and imaging devices. However, due to inherent properties of ceramics, such as high chemical inertness, low diffusivity, and high melting point, it is difficult to process large or complex-shaped components, making ceramic bonding a challenging technology and limiting the development of ceramics.

[0003] CN114012255A discloses a method for welding ceramic materials, comprising: a first ceramic workpiece having a first joint end face for welding, a second ceramic workpiece having a second joint end face for welding, and filling the space between the first and second joint end faces with solder, the solder comprising ceramic powder; heating the solder to form a sintered body connecting the first and second joint end faces, thereby achieving a tight connection between the first and second joint end faces. The solder used includes ceramic powder and photocurable resin, and the solder is heated using laser or EB methods to achieve welding. However, the above-mentioned aluminum nitride material welding process is prone to defects such as porosity, inclusions, and looseness inside the weld due to uneven solder coating. On the one hand, it cannot meet the requirements of a high vacuum and leak-free working environment, as process gases can easily leak through the defects, affecting the accuracy of the heating process; on the other hand, the defects can block the heat conduction path at the welding interface, leading to uneven heat conduction between the support and the disk, resulting in poor overall temperature field uniformity of the heater, and making it impossible to achieve uniform heating of workpieces such as wafers. In addition, a single solder composition layer can lead to significant differences in the composition of the disk, support, and solder, resulting in a mismatch in the coefficients of thermal expansion and thus causing thermal stress cracking.

[0004] In summary, there is an urgent need to develop a welding method for aluminum nitride heaters that can avoid welding defects caused by uneven solder coating and welding cracks and failures caused by excessive differences in thermal expansion coefficients. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a welding method for the aluminum nitride heater support and the disk, which can avoid welding defects, cracks, and failures, and achieve effective welding of the support and the disk.

[0006] To achieve this objective, the present invention adopts the following technical solution: This invention provides a welding method for an aluminum nitride heater support and a disk, comprising the following steps: (1) Aluminum nitride powder, sintering aid, binder, dispersant and solvent are mixed by ball milling, and the resulting slurry is cast to obtain a cast sheet; (2) Place the cast film obtained in step (1) between the pretreated disk welding surface and the support welding surface, fix it and then perform pressureless welding to complete the welding of the aluminum nitride heater support and the disk. Step (1) The cast sheet includes two outer cast sheets and a transition layer cast sheet disposed between the two outer cast sheets. The sintering aid content of the outer cast sheets is greater than the sintering aid content of the transition layer cast sheets.

[0007] The welding method for the aluminum nitride heater support and disk provided by this invention uses aluminum nitride cast sheets with added sintering aids instead of solder for welding the support and disk. This avoids welding defects caused by uneven solder coating. Furthermore, the layering of aluminum nitride cast sheets with different compositions achieves a smooth transition, preventing excessive differences in the thermal expansion coefficients of the disk, support, and solder, which could lead to welding cracks or failures during repeated heating and cooling processes. Using the welding method proposed in this invention can extend the service life of the heater and reduce costs.

[0008] Preferably, the mass ratio of the ball material to the ball milling mixture in step (1) is (5-10):1, for example, it can be 5:1, 6:1, 8:1, 9:1 or 10:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0009] Preferably, the ball milling mixing time in step (1) is 12-48h, for example, it can be 12h, 18h, 24h, 30h or 48h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0010] Preferably, based on a total mass percentage of 100wt%, the solid raw material composition in the mixed slurry in step (1) includes: 63.5-88.5wt% aluminum nitride powder, 5-30wt% sintering aid, 2-5wt% binder, and 1-1.5wt% dispersant.

[0011] The mass percentage of aluminum nitride powder in the solid phase raw material composition of the mixed slurry is 63.5-88.5 wt%, for example, it can be 63.5 wt%, 65 wt%, 70 wt%, 77 wt%, 80 wt% or 88.5 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] The mass percentage of sintering aid in the solid phase raw material composition of the mixed slurry is 5-30 wt%, for example, it can be 5 wt%, 10 wt%, 13.7 wt%, 15 wt%, 20 wt%, 25 wt% or 30 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] The mass percentage of binder in the solid phase raw material composition of the mixed slurry is 2-5 wt%, for example, it can be 2 wt%, 2.5 wt%, 3.7 wt%, 4 wt% or 5 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] The mass percentage of dispersant in the solid phase raw material composition of the mixed slurry is 1-1.5 wt%, for example, it can be 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt% or 1.5 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, the sintering aid content of the outer layer tape is 20-30 wt%, and the sintering aid content of the transition layer tape is 5-15 wt%.

[0016] The sintering aid content of the outer layer cast sheet is 20-30wt%, for example, it can be 20wt%, 22wt%, 25wt%, 28wt% or 30wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] The sintering aid content of the transition layer cast sheet is 5-15wt%, for example, it can be 5wt%, 8wt%, 10wt%, 12wt% or 15wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Preferably, the solid content of the mixed slurry in step (1) is 40-50 wt%, for example, it can be 40 wt%, 42 wt%, 45 wt%, 48 wt% or 50 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the purity of the aluminum nitride powder in step (1) is ≥99.9%, for example, it can be 99.9%, 99.92%, 99.95%, 99.96% or 99.98%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the aluminum nitride powder in step (1) has a particle size of 0.5-3 μm, for example, it can be 0.5 μm, 1 μm, 1.5 μm, 2 μm or 3 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the sintering aid in step (1) includes metal oxides and / or metal fluorides, wherein the metal includes at least one of Si, Y, Ga, Na or Mg.

[0022] The metal oxide can be SiO2, Y2O3, Ga2O3, Na2O, or MgO, and the metal fluoride can be SiF4, YF3, GaF3, NaF, or MgF2, but is not limited to the listed types. Those skilled in the art can make appropriate selections based on the actual application scenario.

[0023] Preferably, the adhesive in step (1) includes any one of PVB, acrylic resin or ethyl cellulose.

[0024] Preferably, the dispersant in step (1) includes BYK-163 or BYK-111.

[0025] Preferably, the solvent in step (1) includes at least one of anhydrous ethanol, isopropanol, or n-butanol.

[0026] Preferably, the casting process in step (1) includes a defoaming step before the casting process.

[0027] The degassing method described herein is a conventional technique in this field and will not be elaborated upon here.

[0028] Preferably, the pretreatment in step (2) includes sandblasting and cleaning performed sequentially.

[0029] Preferably, the roughness of the weld surface after sandblasting is 1-2 μm, for example, it can be 1 μm, 1.2 μm, 1.5 μm, 1.8 μm or 2 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] The sandblasting process can improve the bonding effect between the support welding surface, the disc welding surface and the cast film.

[0031] Preferably, the cleaning process includes sequential degreasing agent cleaning, ultrasonic cleaning, and wiping.

[0032] Preferably, the degreasing agent used in the degreasing cleaning includes a surfactant.

[0033] The degreasing agent cleaning can remove oil and other contaminants such as cutting fluid from the machining process.

[0034] Preferably, the reagents used for ultrasonic cleaning include anhydrous ethanol or isopropanol.

[0035] Preferably, the reagent used for the wiping treatment includes acetone.

[0036] Preferably, the fixing in step (2) is done by using tooling, then by applying pressure with bolts, and using a torque wrench to control the pressure.

[0037] The present invention does not specifically limit the range of pressure applied during the fixation process, and those skilled in the art can make adaptive adjustments according to the actual application scenario.

[0038] Preferably, the temperature of the pressureless welding in step (2) is 1650-1800℃ and the time is 2-5h.

[0039] The pressureless welding temperature is 1650-1800℃, for example, it can be 1650℃, 1680℃, 1700℃, 1750℃ or 1800℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0040] The pressureless welding time is 2-5 hours, for example, it can be 2 hours, 2.5 hours, 3 hours, 4 hours or 5 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0041] Preferably, the pressureless welding in step (2) is performed in a nitrogen atmosphere.

[0042] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0043] Compared with the prior art, the present invention has the following beneficial effects: The welding method for the aluminum nitride heater support and disk provided by this invention uses aluminum nitride cast sheets with added sintering aids instead of solder for welding the support and disk. This avoids welding defects caused by uneven solder coating. Furthermore, the layering of aluminum nitride cast sheets with different compositions achieves a smooth transition, preventing excessive differences in the thermal expansion coefficients of the disk, support, and solder, which could lead to welding cracks or failures during repeated heating and cooling processes. Using the welding method proposed in this invention can extend the service life of the heater and reduce costs. Detailed Implementation

[0044] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0045] Example 1 This embodiment provides a welding method for the aluminum nitride heater support and the disk body, including the following steps: (1) Aluminum nitride powder with a purity of 99.98% and a particle size of 2μm, SiO2, PVB binder, BYK-163 dispersant and anhydrous ethanol were ball-milled for 30h at a ball-to-material mass ratio of 8:1. The resulting mixed slurry with a solid content of 45wt% was then cast to obtain two outer layer cast sheets. Based on a total mass percentage of 100wt%, the solid raw material composition in the mixed slurry included: 70wt% aluminum nitride powder, 25wt% SiO2, 3.7wt% PVB binder, and 1.3wt% BYK-163 dispersant.

[0046] Aluminum nitride powder with a purity of 99.98% and a particle size of 2μm, SiO2, PVB binder, BYK-163 dispersant, and anhydrous ethanol were ball-milled for 30 hours at a ball-to-particle mass ratio of 8:1. The resulting mixed slurry with a solid content of 45wt% was then cast to obtain a transition layer sheet. Based on a total mass percentage of 100wt%, the solid raw material composition of the mixed slurry included: 80wt% aluminum nitride powder, 13.7wt% SiO2, 5wt% PVB binder, and 1.3wt% BYK-163 dispersant.

[0047] The transition layer tape is placed between the two outer layer tapes to form a combined tape.

[0048] (2) The welding surfaces of the disc and the support are sandblasted to a roughness of 1.5 μm. Then, they are cleaned with detergent, ultrasonically cleaned with anhydrous ethanol and wiped with acetone. The combined cast film obtained in step (1) is placed between the welding surfaces of the disc and the support, fixed with tooling, and then pressurized with bolts. Then, pressureless welding is performed in a nitrogen atmosphere in a pressureless furnace at a temperature of 1700℃ for 3 hours to complete the welding of the aluminum nitride heater support and the disc.

[0049] Example 2 This embodiment provides a welding method for the aluminum nitride heater support and the disk body, including the following steps: (1) Aluminum nitride powder with a purity of 99.95% and a particle size of 0.5μm, Y2O3, acrylic resin binder, BYK-163 dispersant and isopropanol were ball-milled for 12 hours with a ball-to-material mass ratio of 5:1. The resulting mixed slurry with a solid content of 40wt% was cast to obtain two outer cast sheets. Based on a total mass percentage of 100wt%, the solid raw material composition of the mixed slurry included: 77wt% aluminum nitride powder, 20wt% Y2O3, 2wt% acrylic resin binder and 1wt% BYK-163 dispersant.

[0050] Aluminum nitride powder with a purity of 99.98% and a particle size of 0.5-3μm, Y2O3, acrylic resin binder, BYK-163 dispersant, and isopropanol are ball-milled and mixed for 12-48 hours at a ball-to-particle mass ratio of (5-10):1. The resulting mixed slurry with a solid content of 40-50wt% is then cast to obtain a transition layer cast sheet. Based on a total mass percentage of 100wt%, the solid phase raw material composition of the mixed slurry includes: 88.5wt% aluminum nitride powder, 5wt% Y2O3, 5wt% acrylic resin binder, and 1.5wt% BYK-163 dispersant.

[0051] The transition layer tape is placed between the two outer layer tapes to form a combined tape.

[0052] (2) The welding surfaces of the disc and the support are sandblasted to a roughness of 1 μm. Then, they are cleaned with detergent, ultrasonically cleaned with anhydrous ethanol, and wiped with acetone. The combined cast film obtained in step (1) is placed between the welding surfaces of the disc and the support, fixed with tooling, and then pressurized with bolts. Then, pressureless welding is performed in a nitrogen atmosphere in a pressureless furnace at a temperature of 1650℃ for 5 hours to complete the welding of the aluminum nitride heater support and the disc.

[0053] Example 3 This embodiment provides a welding method for the aluminum nitride heater support and the disk body, including the following steps: (1) Aluminum nitride powder with a purity of 99.9% and a particle size of 3μm, GaF3, ethyl cellulose binder, BYK-111 dispersant and n-butanol were ball-milled for 48 hours with a ball-to-particle mass ratio of 10:1. The resulting mixed slurry with a solid content of 50wt% was then cast to obtain two outer layer cast sheets. Based on a total mass percentage of 100wt%, the solid raw material composition in the mixed slurry included: 63.5wt% aluminum nitride powder, 30wt% GaF3, 5wt% ethyl cellulose binder, and 1.5wt% BYK-111 dispersant.

[0054] Aluminum nitride powder with a purity of 99.9% and a particle size of 3 μm, GaF3, ethyl cellulose binder, BYK-111 dispersant, and n-butanol were ball-milled and mixed for 48 hours at a ball-to-particle mass ratio of 10:1. The resulting mixed slurry with a solid content of 50 wt% was then cast to obtain a transition layer sheet. Based on a total mass percentage of 100 wt%, the solid phase raw material composition of the mixed slurry included: 80 wt% aluminum nitride powder, 15 wt% GaF3, 4 wt% ethyl cellulose binder, and 1 wt% BYK-111 dispersant.

[0055] The transition layer tape is placed between the two outer layer tapes to form a combined tape.

[0056] (2) The welding surfaces of the disc and the support are sandblasted to a roughness of 2 μm. Then, they are cleaned with detergent, ultrasonically cleaned with anhydrous ethanol, and wiped with acetone. The combined cast film obtained in step (1) is placed between the welding surfaces of the disc and the support, fixed with tooling, and then pressurized with bolts. Then, pressureless welding is performed in a nitrogen atmosphere in a pressureless furnace at a temperature of 1800℃ for 2 hours to complete the welding of the aluminum nitride heater support and the disc.

[0057] Example 4 This embodiment provides a welding method for an aluminum nitride heater support and a disk. The difference from Embodiment 1 is that the mass percentage of SiO2 in the outer layer tape described in step (1) is adjusted to 35wt%, and the mass percentage of aluminum nitride powder is adaptively adjusted to 60wt%. The rest are the same as in Embodiment 1.

[0058] Example 5 This embodiment provides a welding method for an aluminum nitride heater support and a disk. The difference from Embodiment 1 is that the mass percentage of SiO2 in the transition layer tape described in step (1) is adjusted to 3.7wt%, and the mass percentage of aluminum nitride powder is adaptively adjusted to 90wt%. The rest are the same as in Embodiment 1.

[0059] Example 6 This embodiment provides a welding method for an aluminum nitride heater support and a disc. The difference from Embodiment 1 is that the solid content of the mixed slurry in step (1) is adjusted to 30wt%, while the rest is the same as in Embodiment 1.

[0060] Example 7 This embodiment provides a welding method for an aluminum nitride heater support and a disk. The difference from Embodiment 1 is that the solid content of the mixed slurry in step (1) is adjusted to 60wt%, while the rest is the same as in Embodiment 1.

[0061] Example 8 This embodiment provides a welding method for an aluminum nitride heater support and a disc. The difference from Embodiment 1 is that the temperature of the pressureless welding in step (2) is adjusted to 1600℃, while the rest is the same as in Embodiment 1.

[0062] Example 9 This embodiment provides a welding method for an aluminum nitride heater support and a disc. The difference from Embodiment 1 is that the temperature of the pressureless welding in step (2) is adjusted to 1850°C, while the rest is the same as in Embodiment 1.

[0063] Comparative Example 1 This comparative example provides a welding method for an aluminum nitride heater support and a disc. The difference from Example 1 is that step (1) only sets the same three-layer cast film with 25wt% SiO2 content, while the rest is the same as Example 1.

[0064] Comparative Example 2 This comparative example provides a welding method for an aluminum nitride heater support and a disc. The difference from Example 1 is that step (2) does not include sandblasting, detergent cleaning, anhydrous ethanol ultrasonic cleaning, and acetone wiping. All other steps are the same as in Example 1.

[0065] The aluminum nitride heater welded structure was obtained by welding the aluminum nitride heater support and the disk body using the welding methods provided in Examples 1-9 and Comparative Examples 1 and 2. The weld was inspected for defects using an ultrasonic flaw detector, and the results were divided into "yes" and "no". After 50 cycles of use, the weld was inspected for cracking using an ultrasonic detector, and the results were divided into "cracked" and "no crack". The results are shown in Table 1.

[0066] Table 1 As can be seen from Table 1, the welding method for the aluminum nitride heater support and the disk provided by the present invention can achieve high-quality welding between the support and the disk. There are no defects such as porosity, inclusions, or looseness inside the weld. Moreover, the aluminum nitride heater does not crack after repeated use, which significantly extends its service life.

[0067] A comparison of Examples 1 with Examples 4 and 5 shows that excessive sintering aid in the outer layer tape will lead to certain defects at the weld joint; excessive sintering aid in the transition layer tape will lead to agglomeration of the aid and poor welding. A comparison of Examples 1 with Examples 6 and 7 shows that excessively low solid content in the mixed slurry will lead to certain defects at the weld joint and cracking; excessively high solid content will lead to cracking of the tape layer. A comparison of Examples 1 with Examples 8 and 9 shows that excessively low pressureless welding temperature will lead to incomplete sintering of the tape and welding defects; excessively high temperature will lead to grain growth in the matrix material and affect performance.

[0068] A comparison of Example 1 and Comparative Example 1 shows that using the same sintering aid content in all three layers of cast sheets leads to significant differences in the composition of the disc, support, and solder, resulting in excessively large differences in their coefficients of thermal expansion. This, in turn, causes the heater to crack and fail during repeated heating and cooling processes. A comparison of Example 1 and Comparative Example 2 shows that the lack of pretreatment on the welding surfaces of the support and disc leads to a decreased welding bond, resulting in large-area defects and insufficient strength for use.

[0069] In summary, the welding method for the aluminum nitride heater support and the disk provided by this invention uses aluminum nitride cast sheets with added sintering aids instead of solder for welding the support and the disk. This avoids welding defects caused by uneven solder coating. Furthermore, the layering of aluminum nitride cast sheets with different compositions achieves a smooth transition, preventing excessive differences in the thermal expansion coefficients caused by large differences in the composition of the disk, support, and solder, which could lead to welding cracks and failures during repeated heating and cooling processes in the heater. Using the welding method proposed in this invention can extend the service life of the heater and reduce costs.

[0070] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for welding an aluminum nitride heater support to a disk, characterized in that, Includes the following steps: (1) Aluminum nitride powder, sintering aid, binder, dispersant and solvent are mixed by ball milling, and the resulting slurry is cast to obtain a cast sheet; (2) Place the cast film obtained in step (1) between the pretreated disk welding surface and the support welding surface, fix it and then perform pressureless welding to complete the welding of the aluminum nitride heater support and the disk. The tape in step (2) includes two outer tapes and a transition tape disposed between the two outer tapes. The sintering aid content of the outer tapes is greater than that of the transition tape.

2. The welding method according to claim 1, characterized in that, The mass ratio of the ball material to the ball milling mixture in step (1) is (5-10):1; Preferably, the ball milling mixing time in step (1) is 12-48 hours.

3. The welding method according to claim 1 or 2, characterized in that, Based on a total mass percentage of 100wt%, the solid raw material composition in the mixed slurry in step (1) includes: 63.5-88.5wt% aluminum nitride powder, 5-30wt% sintering aid, 2-5wt% binder, and 1-1.5wt% dispersant.

4. The welding method according to claim 3, characterized in that, The sintering aid content of the outer layer tape is 20-30 wt%, and the sintering aid content of the transition layer tape is 5-15 wt%.

5. The welding method according to any one of claims 1-4, characterized in that, The solid content of the mixed slurry in step (1) is 40-50 wt%.

6. The welding method according to any one of claims 1-5, characterized in that, The purity of the aluminum nitride powder in step (1) is ≥99.9%; Preferably, the aluminum nitride powder in step (1) has a particle size of 0.5-3 μm.

7. The welding method according to any one of claims 1-6, characterized in that, The sintering aid in step (1) includes metal oxides and / or metal fluorides, wherein the metal includes at least one of Si, Y, Ga, Na or Mg; Preferably, the adhesive in step (1) comprises any one of PVB, acrylic resin or ethyl cellulose; Preferably, the dispersant in step (1) includes BYK-163 or BYK-111; Preferably, the solvent in step (1) includes at least one of anhydrous ethanol, isopropanol, or n-butanol.

8. The welding method according to any one of claims 1-7, characterized in that, The pretreatment in step (2) includes sandblasting and cleaning performed sequentially.

9. The welding method according to claim 8, characterized in that, The roughness of the weld surface after sandblasting is 1-2 μm; Preferably, the cleaning process includes sequential degreasing agent cleaning, ultrasonic cleaning, and wiping.

10. The welding method according to any one of claims 1-9, characterized in that, The pressureless welding temperature in step (2) is 1650-1800℃, and the time is 2-5h; Preferably, the pressureless welding in step (2) is performed in a nitrogen atmosphere.

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