Manufacturing method for Al2O3 sintered parts

Abstract

To provide a method of producing a sintered member of Al2O3 having a hollow structure of high dimension accuracy.SOLUTION: A method of producing a sintered member of Al2O3, comprises a process of calcining a first Al2O3 molding at a temperature of not lower than 1000°C and not higher than 1500°C to obtain a first calcined body of Al2O3, a process of calcining a second Al2O3 molding at a temperature of not lower than 1000°C and not higher than 1500°C to obtain a second calcined body of Al2O3, a process of forming a first plane on the first calcined body of Al2O3, a process of forming a second plane on the surface of the second calcined body of Al2O3, a process of forming a recessed part at least on either of the first plane and the second plane, a process of laminating the first calcined body of Al2O3 and the second calcined body of Al2O3 so as to keep the first plane and the second plane in a state of contacting each other, and a process of firing the first calcined body of Al2O3 and the second calcined body of Al2O3 laminated each other at a temperature of not lower than 1400°C and not higher than 1800°C while applying a pressure of 10 kgf / cm2 or greater thereto in the lamination direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing an Al2O3 sintered part. [Background technology]

[0002] In semiconductor manufacturing equipment, a base serving as a mounting table for a ceramic electrostatic chuck or the like that holds a substrate such as a wafer on its surface is heated together with the electrostatic chuck, and therefore has a similar thermal expansion coefficient to the electrostatic chuck, and may be subjected to high voltage, so it is sometimes preferable for the base to be made of a material with a high volume resistivity. One such material is an Al2O3 sintered compact.

[0003] However, since the sintering temperature of an Al2O3 sintered body is high and it is difficult to process, a base having a hollow structure therein made of an Al2O3 sintered body has not been put to practical use very often.

[0004] Patent Document 1 discloses a technique for integrating ceramic calcined bodies by firing them under a load at normal pressure. As an example, it gives a technique in which Al2O3 calcined bodies calcined at a temperature of 1100°C or 1500°C are integrated by firing them at a temperature of 1580°C or 1800°C under a load with a weight placed on them.

[0005] In addition, Patent Document 2 describes a method for adjusting α-Al2O3 and γ-Al2O3 to have a specific surface area of ​​15 to 100 m 2 The paper discloses a technique in which a pressed compact or a calcined body is produced using Al2O3 powder with a molecular weight of 0.15g / g as a raw material, and these are bonded under a pressure exceeding the molding pressure, and then the bonded body is fired at a temperature of 1300°C or higher to obtain an Al2O3 sintered member. In the example, the pressed compact is calcined at a maximum temperature of 900°C to produce a calcined body. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-298574 [Patent Document 2] JP 2000-26172 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technique described in Patent Document 1 has a problem in that the density of the Al2O3 sintered member is not sufficient.

[0008] On the other hand, in the technology described in Patent Document 2, the calcined body has a high porosity, which results in a large deformation during bonding and firing, and even if a recess is formed on the bonding surface of the calcined body, the deformation makes it impossible to obtain an Al2O3 sintered component having a hollow structure with high dimensional accuracy.

[0009] The present invention has been made in consideration of the above circumstances, and has an object to provide a manufacturing method for an Al2O3 sintered part that can obtain an Al2O3 sintered part having a hollow structure with high density and dimensional accuracy. [Means for solving the problem]

[0010] The method for producing an Al2O3 sintered member of the present invention includes calcining a first Al2O3 molded body at a temperature of 1000°C to 1500°C. Relative density 72% to 91% A step of obtaining a first calcined Al2O3 body, and calcining the second Al2O3 compact at a temperature of 1000°C or more and 1500°C or less. Relative density 72% to 91% The present invention relates to a method for manufacturing a laminated laminated Al2O3 calcined body, comprising the steps of: obtaining a second Al2O3 calcined body; forming a first plane on the first Al2O3 calcined body; forming a second plane on the second Al2O3 calcined body; forming recesses on at least one of the first plane and the second plane; stacking the first Al2O3 calcined body and the second Al2O3 calcined body in a state in which the first plane and the second plane are in contact with each other; and applying a pressure of 10 kgf / cm to the stacked first Al2O3 calcined body and the second Al2O3 calcined body in a stacking direction. 2and firing the mixture at 1400° C. or more and 1800° C. or less while applying a pressure of 0.98 MPa or more.

[0011] According to the manufacturing method of the Al2O3 sintered member of the present invention, it is possible to obtain an Al2O3 sintered member having a hollow structure derived from the recesses. The first and second flat surfaces and recesses are formed on the first and second Al2O3 calcined bodies, and the grinding, polishing, and other operations for forming them can be shortened compared to the case of forming them on the Al2O3 sintered body. In addition, it is possible to improve the dimensional accuracy of the hollow structure of the Al2O3 sintered member derived from the recesses compared to the case of integrating the Al2O3 molded bodies with recesses by firing them together.

[0012] In addition, compared to the technique disclosed in the above Patent Document 1, in which firing is performed under a small load using a weight, 2 Since the firing is performed while applying a pressure of at least 0.98 MPa (=0.98 MPa), it is possible to densify the Al2O3 sintered component.

[0013] Furthermore, compared to the technology disclosed in the above Patent Document 2 in which the calcined body is calcined at a maximum temperature of 900°C so that the calcined body has a high porosity, the first and second Al2O3 calcined bodies are obtained by calcining the first and second Al2O3 molded bodies at a temperature of 1000°C to 1500°C, so that the porosity of the first and second Al2O3 calcined bodies is low. This makes it possible to improve the dimensional accuracy of the hollow structure of the Al2O3 sintered member obtained by stacking these bodies and firing them while applying pressure in the stacking direction.

[0014] The first method for producing an Al2O3 sintered member of the present invention preferably further comprises a step of storing the first Al2O3 calcined body and the second Al2O3 calcined body prior to the step of forming the recess.

[0015] In this case, by storing the first and second Al2O3 calcined bodies prepared in advance, it is possible to obtain an Al2O3 sintered member in a time that is at least shorter than the time required for calcination. Also, by storing the first and second Al2O3 calcined bodies on which the first and second flat surfaces are formed, it is possible to obtain an Al2O3 sintered member in a time that is also shorter than the time required for the process of forming the first and second flat surfaces.

[0016] Moreover, in the manufacturing method of the Al2O3 sintered member of the present invention, it is preferable that the method further comprises a step of calcining the third Al2O3 molded body at a temperature of 1000°C or more and 1500°C or less to obtain a third Al2O3 calcined body, and that in the stacking step, the third Al2O3 calcined body is stacked on the outer side in the stacking direction of the first Al2O3 calcined body or the second Al2O3 calcined body via a release material, and that in the firing step, the pressure is applied to the stacked first Al2O3 calcined body, the second Al2O3 calcined body and the third Al2O3 calcined body.

[0017] In this case, by applying pressure to the stepped or recessed portion of the first or second Al2O3 calcined body with the third Al2O3 calcined body placed through a release material, the third Al2O3 calcined body shrinks similarly to the first and second Al2O3 calcined bodies during firing, making it possible to equalize the pressure applied during firing and improve the bonding strength. In addition, after firing, the sintered body portion corresponding to the third Al2O3 calcined body can be easily peeled off, making it unnecessary to remove it by machining or the like.

[0018] In the method for producing an Al2O3 sintered member of the present invention, it is preferable that at least one of the first flat surface, the second flat surface, and the recessed portion is formed by dry grinding or polishing.

[0019] In this case, compared to the case where wet grinding or polishing is performed, the grinding fluid or polishing fluid penetrates into the inside of the first or second Al2O3 calcined body, thereby making it possible to eliminate the risk of impurities remaining in the Al2O3 sintered component. [Brief description of the drawings]

[0020] [Figure 1] 1 is a flowchart showing a method for producing an Al2O3 sintered member according to a first embodiment of the present invention. [Figure 2A] FIG. 2 is a schematic cross-sectional view showing the first and second Al2O3 calcined bodies. [Figure 2B] FIG. 2 is a schematic cross-sectional view showing a state in which the first and second calcined Al2O3 bodies are stacked. [Figure 2C] FIG. 2 is a schematic cross-sectional view showing an Al2O3 sintered member. [Diagram 3] 5 is a flowchart showing a method for producing an Al2O3 sintered member according to a second embodiment of the present invention. [Figure 4A] FIG. 2 is a schematic cross-sectional view showing the first to third calcined Al2O3 bodies. [Figure 4B] FIG. 2 is a schematic cross-sectional view showing a state in which first to third calcined Al2O3 bodies are stacked. [Figure 4C] FIG. 2 is a schematic cross-sectional view showing an Al2O3 sintered member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] A method for producing an Al2O3 sintered member 10 according to a first embodiment of the present invention will be described with reference to the drawings. Note that the drawings are deformed to clearly show the Al2O3 sintered member 10 and its components, and do not represent the actual proportions, and the directions such as up and down are merely exemplary.

[0022] As shown in FIG. 1, the method for producing the Al2O3 sintered member 10 according to the first embodiment of the present invention includes a first Al2O3 calcined body obtaining step STEP 1, a second Al2O3 calcined body obtaining step STEP 2, a first plane forming step STEP 3, a second plane forming step STEP 4, a recess forming step STEP 5, a lamination step STEP 6, and a sintering step STEP 7.

[0023] In the first Al2O3 calcined body obtaining step STEP 1, referring to Fig. 2A, the first Al2O3 molded body is calcined at a temperature of 1000°C or more and 1500°C or less to obtain a first Al2O3 calcined body 1. In the second Al2O3 calcined body obtaining step STEP 2, the second Al2O3 molded body is calcined at a temperature of 1000°C or more and 1500°C or less to obtain a second Al2O3 calcined body 2. The calcination temperatures in the first Al2O3 calcined body obtaining step STEP 1 and the second Al2O3 calcined body obtaining step STEP 2 may be the same or different.

[0024] In the first Al2O3 calcined body obtaining step STEP 1 and the second Al2O3 calcined body obtaining step STEP 2, two Al2O3 compacts obtained by compacting Al2O3 (aluminum oxide, alumina) powder are calcined to form the first and second Al2O3 calcined bodies 1 and 2. For example, additives such as a sintering aid and a resin binder are appropriately added to and mixed with Al2O3 powder to prepare a compacting raw material, which is then pressure-molded to form two Al2O3 compacts.

[0025] The Al2O3 powder is preferably of high purity, and the purity is preferably 96% or more, more preferably 98% or more. The average particle size of the Al2O3 powder is preferably 0.1 μm or more and 1.0 μm or less, more preferably 0.3 μm or more and 0.8 μm or less. The Al2O3 powder preferably consists of α-Al2O3.

[0026] The mixing method may be either wet or dry, and a mixer such as a ball mill or a vibration mill may be used. Alternatively, a sintering aid or the like may be added to Al2O3 powder to prepare Al2O3 granules, and an additive such as a resin binder may be added to the Al2O3 granules, which are then pressure molded to form an Al2O3 compact. As a molding method, a known method such as uniaxial pressing or cold isostatic pressing (CIP) may be used.

[0027] Alternatively, the Al2O3 molded body may be heated at a temperature of 900°C or more and less than 1000°C to obtain an Al2O3 degreased body, and then the Al2O3 degreased body may be heated at a temperature of 1000°C or more and 1500°C or less to obtain the first and second Al2O3 calcined bodies 1 and 2. Alternatively, the Al2O3 molded body may be heated while being continuously heated to a temperature of 1000°C or more and 1500°C or less to obtain the first and second Al2O3 calcined bodies 1 and 2.

[0028] In the first plane forming step STEP 3, a first plane 1a is formed on the first Al2O3 calcined body 1. In the second plane forming step STEP 4, a second plane 2a is formed on the second Al2O3 calcined body 2. The first plane 1a and the second plane 2a become surfaces that come into contact with each other in the lamination step STEP 6.

[0029] The first and second planes 1a, 2a are formed by polishing or grinding using a surface grinding machine or lapping machine such as an NC lathe or an MC processing machine so that the surface roughness Ra is preferably 0.15 μm or more and 0.8 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

[0030] In the recess forming step STEP 5, the recess 3 is formed in at least one of the first plane 1a and the second plane 2a. The recess 3 is formed by a grinding process or the like so as to be dug from either or both of the first plane 1a and the second plane 2a.

[0031] In addition, in the first plane formation step STEP 3 or the second plane formation step STEP 4, the first or second plane 1a, 2a may not be polished or may only be roughly ground, and after the recess 3 is formed in the recess formation step STEP 5, the first or second plane 1a, 2a may be polished or subjected to finish grinding.

[0032] When the recesses 3 are formed by carving from both the first and second planes 1a, 2a, these recesses 3 may be integrated when the first and second planes 1a, 2a are brought into contact with each other in the lamination step STEP 5, or may be closed by another plane. It is preferable to chamfer the boundaries between the first and second planes 1a, 2a and the recesses 3 and the bottom corners of the recesses 3 with R- or C-chamfering.

[0033] In addition, in the first plane forming step STEP 3, the second plane forming step STEP 4, or the recess forming step STEP 5, it is preferable to form the first plane 1a, the second plane 2a, or the recess 3 by dry grinding or polishing. This makes it possible to eliminate the possibility that the grinding fluid or polishing fluid will penetrate into the first or second Al2O3 calcined body 1, 2, and impurities will remain in the Al2O3 sintered member 10. In addition, when performing grinding and polishing, it is preferable to perform both of these processes by dry methods.

[0034] Furthermore, a storage step of storing the first and second Al2O3 calcined bodies 1, 2 may be provided before the recess forming step STEP 5. By storing the first and second Al2O3 calcined bodies 1, 2 prepared in advance, it is possible to obtain the Al2O3 sintered member 10 in a time that is at least shorter than the time required for calcination. In addition, by storing the first and second Al2O3 calcined bodies 1, 2 after the first plane forming step STEP 3 and the second plane forming step STEP 4, it is possible to obtain the Al2O3 sintered member 10 in a time that is also shorter than the time required for the steps of forming the first plane 1a and the second plane 2a.

[0035] In the lamination step STEP 6, referring to FIG. 2B, the first calcined Al2O3 body 1 and the second calcined Al2O3 body 2 are laminated with the first flat surface 1a and the second flat surface 2a in contact with each other.

[0036] In the firing step STEP 7, the laminated first Al2O3 calcined body 1 and the second Al2O3 calcined body 2 are fired at 10 kgf / cm in the lamination direction. 2While applying a pressure of 0.98 MPa or more, the mixture is fired at 1400° C. to 1800° C. As a result, referring to FIG. 2C, the first and second Al2O3 calcined bodies 1 and 2 are sintered and integrated to obtain an Al2O3 sintered member 10.

[0037] In the firing step STEP 7, pressure sintering is performed by hot pressing in which pressure is applied at least in the stacking direction. The heating time is preferably 0.1 to 10 hours, more preferably 1 to 5 hours. The firing atmosphere is, for example, an inert gas atmosphere, but may also be a vacuum atmosphere.

[0038] In addition, when a core is inserted into the recess 3 in the lamination step STEP 6, the core may be removed in or after the firing step STEP 7. For example, when the recess 3 is in communication with the outside, the melted core may be discharged to the outside.

[0039] In the case where Al2O3 sintered bodies are diffusion-bonded together to be integrated, since the Al2O3 sintered bodies are difficult to process, a lot of time is required to polish the bonding surfaces, but in comparison, in the manufacturing method of the Al2O3 sintered member 10 according to the first embodiment of the present invention described above, it is possible to reduce the time required to grind or polish the first and second flat surfaces 1a, 2a and the recesses 3 of the first and second Al2O3 calcined bodies 1, 2. In addition, compared to the case where Al2O3 molded bodies with the recesses 3 formed therein are sintered together to be integrated, it is possible to improve the dimensional accuracy of the hollow structure of the Al2O3 sintered member 10 resulting from the recesses 3.

[0040] Furthermore, compared to the technique disclosed in the above Patent Document 1, in which firing is performed under a small load using a weight, 2 Since the firing is performed while applying the above pressure, it is possible to improve the densification of the Al2O3 sintered part 10. 2 If the pressure is less than this, good surface contact between the first and second flat surfaces 1a, 2a of the first and second calcined bodies 1, 2 of Al2O3 is not obtained during firing, which causes poor bonding.

[0041] Next, a method for producing the Al2O3 sintered member 20 according to a second embodiment of the present invention will be described with reference to the drawings.

[0042] As shown in FIG. 3, the manufacturing method of the Al2O3 sintered member 20 according to the second embodiment of the present invention includes a first Al2O3 calcined body obtaining step STEP 11, a second Al2O3 calcined body obtaining step STEP 12, a third Al2O3 calcined body obtaining step STEP 13, a first plane forming step STEP 14, a second plane forming step STEP 15, a recess forming step STEP 16, a stacking step STEP 17, and a sintering step STEP 18.

[0043] In STEP 11 of the first Al2O3 calcined body obtaining step in Fig. 3, referring to Fig. 4A, the first Al2O3 molded body is calcined at a temperature of 1000°C or more and 1500°C or less to obtain a first Al2O3 calcined body 11. In STEP 12 of the second Al2O3 calcined body obtaining step, the second Al2O3 molded body is calcined at a temperature of 1000°C or more and 1500°C or less to obtain a second Al2O3 calcined body 12. The calcination temperatures in STEP 11 of the first Al2O3 calcined body obtaining step and STEP 12 of the second Al2O3 calcined body obtaining step may be the same or different.

[0044] The first Al2O3 calcined body obtaining step STEP 11 is similar to the first Al2O3 calcined body obtaining step STEP 1 in FIG. 1 described above, and the second Al2O3 calcined body obtaining step STEP 12 is similar to the second Al2O3 calcined body obtaining step STEP 2 described above, so their explanations are omitted.

[0045] In the third Al2O3 calcined body obtaining step STEP 13, the third Al2O3 molded body is calcined at a temperature of 1000°C or more and 1500°C or less to obtain a third Al2O3 calcined body 13. The third Al2O3 calcined body 13 may be obtained in the same manner as the above-mentioned first or second Al2O3 calcined body 11, 12. Note that the calcination temperature in the third Al2O3 calcined body obtaining step 13 may be the same as or different from the calcination temperature in the first or second Al2O3 calcined body obtaining step STEP 11, 12.

[0046] The third Al2O3 calcined body 13 is configured to have a shape that eliminates steps or recesses on the outer side in the stacking direction when the first Al2O3 calcined body 11 and the second Al2O3 calcined body 12 are stacked with the first flat surface 11a and the second flat surface 21a in contact with each other in the stacking step STEP 17, as shown in Fig. 4B. For example, when a ring-shaped step is formed on the outer periphery of the surface on the outer side in the stacking direction of the second calcined body 12, the third Al2O3 calcined body 13 is formed as a ring-shaped member having a thickness that is approximately equal to the height of the step.

[0047] Next, in a first plane forming step (STEP 14), a first plane 11a is formed on the first Al2O3 calcined body 11. In a second plane forming step (STEP 15), a second plane 12a is formed on the second Al2O3 calcined body 12.

[0048] The first plane forming step STEP 14 is similar to the above-described first plane forming step STEP 3, and the second plane forming step STEP 15 is similar to the above-described second plane forming step STEP 4, so that the explanation thereof will be omitted.

[0049] Next, recesses 14 are formed in at least one of the first plane 11a or the second plane 12a in a recess forming step STEP 16. The recess forming step STEP 16 is similar to the recess forming step STEP 5 described above, and therefore a description thereof will be omitted.

[0050] Next, in a lamination step STEP 17, referring to FIG. 4B, the first calcined Al2O3 body 11 and the second calcined Al2O3 body 12 are laminated with the first flat surface 11a and the second flat surface 12a in contact with each other.

[0051] Furthermore, in the lamination step STEP 17, the third Al2O3 calcined body 13 is laminated on the outer side in the lamination direction of the first Al2O3 calcined body 11 or the second Al2O3 calcined body 12 via a release material 15. As a result, the first to third Al2O3 calcined bodies 11-13 are laminated in a flat shape with no steps or recesses on the outer side in the lamination direction. For example, a carbon sheet or a boron nitride sheet can be used as the release material 15. Alternatively, the first Al2O3 calcined body 11 or the second Al2O3 calcined body 12 may be directly coated with carbon or boron nitride.

[0052] Next, in the firing step STEP 18, the stacked first to third Al2O3 calcined bodies 11 to 13 are fired at 10 kgf / cm in the stacking direction. 2 While applying the above pressure, the mixture is fired at 1400° C. to 1800° C. The firing step (STEP 18) is similar to the firing step (STEP 7) described above, and therefore a detailed explanation thereof will be omitted.

[0053] 4C, the first and second Al2O3 calcined bodies 11, 12 are sintered and integrated to obtain an Al2O3 sintered member 20. The Al2O3 sintered body (not shown) formed by sintering the third Al2O3 calcined body 13 is only in contact with the Al2O3 sintered member 20 via the release material 15, and is therefore not sintered with the Al2O3 sintered member 20 and can be easily separated from the Al2O3 sintered member 20.

[0054] The method for manufacturing the Al2O3 sintered portion 20 according to the second embodiment of the present invention described above also has the same effects as the method for manufacturing the Al2O3 sintered portion 10 according to the first embodiment of the present invention described above.

[0055] Furthermore, in the manufacturing method of the Al2O3 sintered member 20 according to the second embodiment of the present invention, the third Al2O3 calcined body 13 is placed on a step or a recess on the outer side of the first or second Al2O3 calcined body 11, 12 in the stacking direction via a release material 15, and then the first or second Al2O3 calcined body 11, 12 is pressurized and fired. During firing, the third Al2O3 calcined body 13 shrinks in the same manner as the first and second Al2O3 calcined bodies 11, 12. This makes it possible to uniform the pressure applied to the first and second Al2O3 calcined bodies 11, 12 during firing and to improve the bonding strength.

[0056] The present invention is not limited to the manufacturing method of the Al2O3 sintered member 10, 20 specifically described in the first or second embodiment, and may be modified as appropriate within the scope of the claims. For example, the Al2O3 sintered member 10, 20 is an integrated member of two Al2O3 calcined bodies 1, 2 or 11, 12, but may be an integrated member of three or more Al2O3 calcined bodies. EXAMPLES

[0057] (Examples 1 to 6) In Examples 1 to 6, in the first and second Al2O3 calcined body obtaining steps STEP 1 and 2, first, a slurry was prepared by adding 0.05 mass% MgO and PVA (polyvinyl alcohol) as sintering aids to Al2O3 powder with a purity of 99% and an average particle size of 0.4 μm. Next, the slurry was granulated with a spray dryer to obtain granules.

[0058] The granules were then filled into a metal mold and uniaxially pressed at a pressure of 0.5 MPa to obtain two Al2O3 compacts. The bulk densities of these Al2O3 compacts were as shown in Table 1.

[0059] Next, these Al2O3 compacts were sintered in a sintering furnace in an Ar atmosphere at a furnace temperature of 1000°C to 1500°C as shown in Table 1 for 3 hours to obtain first and second Al2O3 calcined bodies 1 and 2. The bulk density of these first and second Al2O3 calcined bodies 1 and 2 and the shrinkage rate due to calcination with respect to the Al2O3 compact were as shown in Table 1. Both these first and second Al2O3 calcined bodies 1 and 2 were cut into square plates with sides of 100 mm and a thickness of 10 mm.

[0060] Next, as the first and second plane forming steps STEP3 and 4, the two Al2O3 calcined bodies were ground using a grindstone equipped with diamond abrasive grains of #170 in the first Al2O3 calcined body 1 and the second plane 2a of the second Al2O3 calcined body 2 in Examples 1 to 4, as shown in FIG. 2A. In Examples 5 and 6, the grindstone was ground using a grindstone equipped with diamond abrasive grains of #600. The grinding was performed dry without using a polishing liquid. The arithmetic mean roughness (Ra) and the average maximum height (Rz) of the first and second planes 1a and 2a were as shown in Table 1.

[0061] Next, in the recess forming step STEP 5, recesses 3 were formed on the second flat surface 2a of the second Al2O3 calcined body 2. The recesses 3 were three linear grooves with a width of 20 mm, a depth of 5 mm, and a length of 70 mm. The recesses 3 were formed by MC processing using an end mill with a diameter of 20 mm. The evaluation of the workability of this MC processing is shown in Table 1.

[0062] The evaluation was based on the load on the spindle during processing, chattering, and damage to the calcined body. In Table 1, the evaluation "◎" means that the cutting depth in one pass is 0.25 mm or more and the blade feed rate is 250 mm / min or more, which is excellent. The evaluation "〇" means that the cutting depth in one pass is 0.2 mm or more and the blade feed rate is 200 mm / min or more, which is good. The evaluation "△" means that the cutting depth in one pass is 0.15 mm or more and the blade feed rate is 150 mm / min or more, which is acceptable. The evaluation "×" means that the cutting depth in one pass is less than 0.15 mm or the blade feed rate is less than 150 mm / min, which is poor. The evaluation "XX" means that the calcined body was damaged during processing, which is poor.

[0063] From this, it was found that, with regard to the workability when forming the recesses 3, it is possible to form the recesses 3 if the calcination temperature is 1000° C. or more and 1500° C. or less, but it is preferable if it is 1200° C. or more and 1300° C. or less. If the calcination temperature is lower than 1200° C., the strength of the calcined body decreases. By doing so, it was found that the calcined body would break under high load conditions. Ta.

[0064] Next, in a lamination step STEP 6, referring to FIG. 2B, the first calcined Al2O3 body 1 and the second calcined Al2O3 body 2 were laminated with the first flat surface 1a and the second flat surface 2a in contact with each other.

[0065] Next, in the sintering step STEP 7, the first and second Al2O3 calcined bodies 1 and 2 thus stacked are sandwiched between carbon flat plates as pressing plates in an Ar atmosphere in a sintering furnace, and a pressure of 25 kgf / cm 2 The material was sintered for 3 hours at a furnace temperature of 1600° C. while applying a load of 2.45 MPa in the lamination direction. As a result, an Al2O3 sintered part 10 was obtained, as shown in FIG. 2C. The bulk density of the Al2O3 sintered part 10 was as shown in Table 1.

[0066] Then, this Al2O3 sintered component 10 was cut to include the joint, and the cut surface was polished, after which the joint was visually inspected by an experimenter using a magnifying glass, etc. As a result, no poor bonding or damage was found at the joint, and no damage or distortion was found in the hollow structure originating from the recess 3.

[0067] The results of Examples 1 to 5 are summarized in Table 1.

[0068] [Table 1]

[0069] Comparative Example 1 In Comparative Example 1, an Al2O3 compact prepared in the same manner as in Examples 1 to 6 was sintered in a sintering furnace in an Ar atmosphere at a furnace temperature of 1600°C for 3 hours to obtain two Al2O3 sintered bodies. That is, in Comparative Example 1, an Al2O3 sintered body was used instead of the Al2O3 calcined bodies 1 and 2. An attempt was made to form a recess 3 in the Al2O3 sintered body by using the MC processing machine that formed the recess 3 in Examples 1 to 6, but this was very difficult and was abandoned midway.

[0070] Comparative Example 2 In Comparative Example 2, an Al2O3 compact prepared in the same manner as in Examples 1 to 6 was sintered in a sintering furnace in an argon atmosphere at a furnace temperature of 900°C for 3 hours to obtain two Al2O3 calcined bodies. An attempt was made to form recesses 3 in the Al2O3 calcined bodies by using the MC processing machine used to form recesses 3 in Examples 1 to 6, but the calcined bodies were damaged during processing, so this attempt was abandoned midway.

[0071] Comparative Example 3 In Comparative Example 3, the load applied to the first and second Al2O3 calcined bodies 1 and 2 stacked in the firing step STEP 7 was 5 kgf / cm 2 The Al2O3 sintered member 30 was produced in the same manner as in Example 2, except that the pressure was set to (=0.49 MPa). Although the sintered body had a high density and was dense, cross-sectional observation confirmed that there were unjoined portions in the joints, and the sintered member was not suitable for use as the Al2O3 sintered member 10 having a hollow structure.

[0072] The results of Comparative Examples 1 to 3 are summarized in Table 2. Although Comparative Example 1 was fired at 1600° C., in Table 2, this is shown in the column for calcined body for convenience.

[0073] [Table 2]

[0074] Example 7 In Example 7, the Al2O3 sintered member 10 was produced in the same manner as in Example 6, except that the first and second Al2O3 calcined bodies 1, 2 were disk-shaped with a diameter of 400 mm and a thickness of 10 mm, and a diameter of 400 mm and a thickness of 25 mm, respectively.

[0075] Example 8 In Example 8, the first and second Al2O3 calcined bodies 1 and 2 were obtained in the same manner as in Example 7. The first and second Al2O3 calcined bodies 1 and 2 were then cut into disks having a diameter of 400 mm and a thickness of 10 mm, and disks having a diameter of 400 mm and a thickness of 25 mm, respectively. Next, in the first and second plane forming steps SEP 3 and SEP 4, a first plane 1a was formed on the first Al2O3 calcined body 1, and a second plane 2a was formed on the second Al2O3 calcined body 2, in the same manner as in Example 6. Furthermore, in the recess forming step SEP 5, recesses 3 were formed by MC processing similar to that in Example 6.

[0076] The first and second flat surfaces 1a, 2a were ground using a grindstone equipped with diamond abrasive grains of #600, and the arithmetic mean roughness (Ra) of the first and second flat surfaces 1a, 2a was set to 0.27 μm. Furthermore, the first and second flat surfaces 1a, 2a were slid using an Al2O3 sintered body having a flat surface with a surface roughness Ra of 0.01 μm while applying a pressure of 6000 Pa in a direction perpendicular to the flat surface in a dry state, and the surface roughness Ra of the flat surfaces 1a, 2a was set to 0.18 μm.

[0077] Next, in a lamination step STEP 6, the first calcined Al2O3 body 1 and the second calcined Al2O3 body 2 were laminated in a state in which the first plane 1a and the second plane 2a were in contact with each other in the same manner as in Example 6.

[0078] Next, in the firing step (STEP 7), firing was performed in the same manner as in Example 6. As a result, an Al2O3 sintered part 10 was obtained, as shown in Fig. 2C.

[0079] Similarly to Example 6, the Al2O3 sintered members 10 obtained in Examples 7 and 8 did not show any bonding failure or breakage at the bonded portion, and did not show any breakage or distortion in the hollow structure originating from the recess 3. The results of Examples 7 and 8 are summarized in Table 3. It was confirmed that the Al2O3 sintered members 10 produced in Examples 7 and 8 can be used as a base for an electrostatic chuck.

[0080] Example 9 In Example 9, as the first and second Al2O3 calcined body obtaining steps SEP 11 and SEP 12 in Fig. 3, two Al2O3 molded bodies were obtained in the same manner as the first and second Al2O3 calcined body obtaining steps SEP 1 and SEP 2 in Example 6. Next, these Al2O3 molded bodies were fired in a firing furnace in an Ar atmosphere at a furnace temperature of 1500 °C for 3 hours to obtain two Al2O3 calcined bodies.

[0081] In addition, as a third Al2O3 calcined body obtaining step STEP 13, one Al2O3 molded body was obtained in the same manner as the first and second Al2O3 calcined body obtaining steps STEP 1 and 2 in Example 6. Next, this Al2O3 molded body was sintered in a sintering furnace in an Ar atmosphere at a furnace temperature of 1500°C for 3 hours to obtain one Al2O3 calcined body 13.

[0082] Next, as the first and second plane forming steps STEP14 and 15 in FIG. 3, referring to FIG. 4A, the two Al2O3 calcined bodies were processed into a first Al2O3 calcined body 11 having a disk shape with a diameter of 350 mm and a thickness of 25 mm and a second Al2O3 calcined body 12 having a disk shape with a diameter of 400 mm and a thickness of 10 mm. The first plane 11a of the first Al2O3 calcined body 11 and the second plane 12a of the second Al2O3 calcined body 12 were ground using a grindstone equipped with diamond abrasive grains of #170. In addition, the one Al2O3 calcined body was processed into a third Al2O3 calcined body 13 having an outer diameter of 400 mm, an inner diameter of 349.5 mm, and a thickness of 25 mm.

[0083] Furthermore, in a recess forming step STEP 16, recesses 14 having the same shape as the recesses 13 in Example 6 were formed in the second flat surface 12a by MC processing.

[0084] Next, in the lamination step STEP 17, referring to Fig. 4B, the first Al2O3 calcined body 11 and the second Al2O3 calcined body 12 were laminated with the first plane 11a and the second plane 12a in contact with each other. Furthermore, the third Al2O3 calcined body 13 was placed on the outer periphery of the second Al2O3 calcined body 12 via a release material 15, and below the first plane 11a of the first Al2O3 calcined body 11 via the release material 15. The release material 15 was a carbon sheet having a thickness of 0.5 mm.

[0085] Next, in a firing step STEP 18, the first to third Al2O3 calcined bodies 11-13 thus stacked were fired in the same manner as in the firing step STEP 7 of Example 1. Thereafter, the fired portion of the third Al2O3 calcined body 13 was peeled off to obtain an Al2O3 sintered member 20 as shown in Fig. 4C.

[0086] Then, this Al2O3 sintered component 20 was cut to include the joint, and the cut surface was polished, after which the experimenter visually inspected the joint using a magnifying glass, etc. As a result, no poor bonding or damage was found at the joint, and no damage or distortion was found in the hollow structure originating from the recess 14.

[0087] The results of Examples 7 to 9 are summarized in Table 3.

[0088] [Table 3] [Explanation of symbols]

[0089] Reference Signs List 1, 11...first Al2O3 calcined body; 1a, 11a...first flat surface; 2, 12...second Al2O3 calcined body; 2a, 12a...second flat surface; 3, 14...recess; 13...third Al2O3 calcined body; 15...peeling material; 10, 20...Al2O3 sintered member.

Claims

1. First Al ２ O ３ The compact is calcined at a temperature of 1000° C. or more and 1500° C. or less to form a first Al having a relative density of 72% to 91%. ２ O ３ Obtaining a calcined body; The second Al ２ O ３ The compact is calcined at a temperature of 1000° C. or more and 1500° C. or less to form a second Al having a relative density of 72% to 91%. ２ O ３ Obtaining a calcined body; The first Al ２ O ３ forming a first plane on the calcined body; The second Al ２ O ３ forming a second plane on the calcined body; forming a recess in at least one of the first plane or the second plane; The first Al ２ O ３ The calcined body and the second Al ２ O ３ a step of stacking the calcined body and the first flat surface in a state where the first flat surface and the second flat surface are in contact with each other; The laminated first Al ２ O ３ The calcined body and the second Al ２ O ３ The calcined body was subjected to a pressure of 10 kgf / cm in the stacking direction. ２ and a step of firing the Al alloy at 1400° C. or more and 1800° C. or less while applying the above pressure. ２ O ３ A method for producing a sintered part.

2. Before the step of forming the recess, the first Al ２ O ３ The calcined body and the second Al ２ O ３ The method according to claim 1, further comprising a step of storing the calcined body. ２ O ３ A method for manufacturing a sintered part.

3. The third Al ２ O ３ The compact is calcined at a temperature of 1000° C. to 1500° C. to form a third Al ２ O ３ Further comprising a step of obtaining a calcined body, In the lamination step, the third Al ２ O ３ The calcined body is treated with the first Al ２ O ３ The calcined body or the second Al ２ O ３ The calcined body is laminated on the outer side in the lamination direction via a release material, In the firing step, the laminated first Al ２ O ３ The calcined body and the second Al ２ O ３ Calcined body and third Al ２ O ３ 3. The Al according to claim 1, wherein the pressure is applied to the calcined body. ２ O ３ A method for manufacturing a sintered part.

4. 4. The Al substrate according to claim 1, wherein at least one of the first plane, the second plane, and the recess is formed by dry grinding or polishing. ２ O ３ A method for producing a sintered part.

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