Method for manufacturing ceramic electrode embedding members and assembly of ceramic electrode embedding members

Abstract

This invention provides a technology for separating a ring-shaped ceramic electrode embedding member, in which an electrode is embedded, from a ceramic sintered body. [Solution] Manufacturing a ring heater 100 with an inner diameter of Φ1 involves preparing a plate-shaped sintered body 200 containing electrodes 120, and separating a disc-shaped portion with an outer diameter of Φ2 (Φ1 > Φ2) from the sintered body 200 by water jet processing.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a ceramic electrode-embedded member and a set of ceramic electrode-embedded members.

Background Art

[0002] Patent Document 1 discloses that a part of an aluminum nitride sintered body is removed by water jet machining by forming a groove extending linearly or a through hole on the surface of the aluminum nitride sintered body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The processing method described in Patent Document 1 is only for forming a groove or through hole on a straight line by removing a part of the ceramic sintered body, and for example, there is no disclosure about separating a ring-shaped ceramic electrode-embedded member in which an electrode is embedded from the ceramic sintered body.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a technique for separating a ring-shaped ceramic electrode-embedded member in which an electrode is embedded from a ceramic sintered body.

Means for Solving the Problems

[0006] According to an aspect of the present invention, there is provided a method for manufacturing a ceramic electrode-embedded member having an annular shape with an inner diameter of Φ1, a step of preparing a plate-shaped ceramic fired body incorporating an electrode, A method for manufacturing a ceramic electrode embedded member is provided, comprising the step of separating a disc-shaped portion with an outer diameter of Φ2 (Φ1>Φ2) from the plate-shaped ceramic sintered body using a water jet or water laser. [Effects of the Invention]

[0007] According to the above configuration, manufacturing a ceramic electrode embedded member with an inner diameter of Φ1 involves preparing a plate-shaped fired body containing the electrode and separating a disc-shaped portion with an outer diameter of Φ2 (Φ1 > Φ2) from the fired body using a water jet or water laser. By performing water jet or water laser processing during the separation of the disc-shaped portion with an outer diameter of Φ2 (Φ1 > Φ2) from the fired body, the release of residual stress in the fired body can be slowed compared to machining, thereby suppressing the occurrence of cracks. Furthermore, while slowing the release of residual stress, it is possible to process by scanning the nozzle at a speed of 8.0 mm / min to 10 mm / min, which is sufficiently faster than conventional machining. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram of the ring heater 100. [Figure 2] Figures (a) to (d) show the flow of the manufacturing method for the ceramic substrate 110. [Figure 3] Figures (a) to (d) show the flow of another method for manufacturing the ceramic substrate 110. [Figure 4] Figure 4 is a schematic diagram illustrating a method for separating the ring-shaped ceramic substrate 110 from the fired body 200. [Figure 5] Figure 5 is a schematic diagram illustrating a method for pre-forming grooves 621 in order to separate the ring-shaped ceramic substrate 110 from the fired body 200. [Figure 6]Figure 6 is a schematic diagram illustrating a method for pre-forming through-holes 625 in order to separate the ring-shaped ceramic substrate 110 from the fired body 200. [Figure 7] Figure 7 is a schematic diagram illustrating a method for using a core 700 to separate a ring-shaped ceramic substrate 110 from a fired body 200. [Figure 8] (a) is a schematic diagram illustrating the process of hot-pressing the CIP molded body 610 in a multi-layered state, and (b) is a schematic diagram illustrating the process of hot-pressing the CIP molded body 610 in a multi-layered state with a core 700 placed in the inner region. [Figure 9] Figure 9 is a schematic diagram illustrating how a ring-shaped ceramic base material 110 with an inner diameter of Φ1 and a disc-shaped portion 230 with an outer diameter of Φ2 are separated from the fired body 200 by water jet processing. [Modes for carrying out the invention]

[0009] <Ring Heater 100> The ring heater 100 according to this embodiment will be described with reference to Figures 1 and 2. The ring heater 100 according to this embodiment is used to hold and heat semiconductor wafers such as silicon wafers (hereinafter simply referred to as wafers). In the following description, the vertical direction 5 is defined based on the state in which the ring heater 100 is installed for use (the state in Figure 1). As shown in Figure 1, the ring heater 100 according to this embodiment mainly comprises a ceramic substrate 110 and an electrode 120. The ring heater 100 is an example of the "ceramic electrode embedded member" of the present invention.

[0010] As shown in Figure 1, the ceramic substrate 110 is a ring-shaped member with an outer diameter Φ3 of 360 mm and an inner diameter Φ1 of 300 mm, and has two main surfaces (upper surface 111 and lower surface 112) facing each other in the vertical direction 5. The wafer to be held is placed on the upper surface 111 of the ceramic substrate 110. In this embodiment, the length (thickness) of the ceramic substrate 110 in the vertical direction 5 is 25 mm. The thickness of the ceramic substrate 110 can be, for example, 5 mm to 35 mm. In this embodiment, the ceramic substrate 110 is formed from an AlN ceramic sintered body. For example, the AlN content can be 50% or more.

[0011] As shown in Figure 1, an electrode 120 for a heater is embedded inside the ceramic substrate 110. Preferably, the electrode 120 is embedded at a position at least 0.5 mm below the upper surface 111 of the ceramic substrate 110. In this embodiment, the electrode 120 is embedded at a position 5 mm below the upper surface 111 of the ceramic substrate 110. In Figure 1, the electrode 120 is shown as an annular shape for clarity, but the electrode 120 actually has a helical, approximately annular shape. The inner diameter Φe of the electrode 120 is 320 mm, and the outer diameter Φ O It is 350mm long and 5mm wide.

[0012] Next, the manufacturing method of the ring heater 100 will be described. In the following explanation, we will use the case where the ceramic substrate 110 is made of AlN ceramics as an example. AlN ceramics are made of AlN ceramics that contain AlN as the main component. Here, AlN ceramics that contain AlN as the main component refers to a ceramic sintered body that contains 50 wt% or more of AlN. Also, for the sake of simplicity, we will assume that only the electrodes 120 are embedded in the ceramic substrate 110.

[0013] Regarding the manufacturing method of the ceramic substrate 110, first, a method for manufacturing the AlN ceramic sintered body 200 will be described, and then a method for separating the ring-shaped ceramic substrate 110 from the sintered body 200 will be described.

[0014] As shown in Fig. 2(a), the granulated powder P mainly composed of AlN powder is put into the carbon floor type 601 and temporarily pressed with the punch 602. The granulated powder P preferably contains a sintering aid (for example, Y2O3) of 7 wt% or less. Next, as shown in Fig. 2(b), the electrode 120 cut into a predetermined shape is arranged on the temporarily pressed granulated powder P. The electrode 120 is arranged so as to be parallel to the surface (the bottom surface of the floor type 601) perpendicular to the pressing direction.

[0015] As shown in Fig. 2(c), the granulated powder P is further put into the floor type 601 so as to cover the electrode 120 and pressed and formed with the punch 602. At this time, the amount of the granulated powder P covering the electrode 120 can be adjusted so that the electrode 120 is buried at a position of 0.5 mm or more in depth. Next, as shown in Fig. 2(d), the granulated powder P in which the electrode 120 is buried is fired in a pressed state (hot press firing). The pressure applied during firing is preferably 1 MPa or more. Also, it is preferably fired at a temperature of 1800 °C or more. It is not always necessary to produce the fired body 200 by firing once. First, a green body may be produced, and the green body may be further fired to obtain the fired body 200.

[0016] The fired body 200 can also be manufactured by the following method. Add 7 wt% or less of a sintering aid (Y2O3) to the AlN raw material powder as needed. Metal carbides, metal nitrides, and metal borides can also be added to the AlN raw material powder. Next, a binder is added to the AlN raw material powder, mixed in ethanol, dried, and then granulated to produce granulated powder P containing AlN as a component. Next, the granulated powder P is filled into a rubber mold and isotropically press-molded (CIP molding) using water pressure to produce two plate-shaped CIP molded bodies 610 (see Figure 3(a)). For example, CIP molding can be performed at a pressure of 130 MPa. Next, the CIP molded bodies 610 are degreased to remove the binder (see Figure 3(b)). Next, as shown in Figure 3(c), a recess 611 for embedding the electrode 120 is formed in one of the degreased CIP molded bodies 610. The recess 611 may be formed in the CIP molded body 610 before the degreasing treatment. After placing the electrode 120 in the recess 611 of the CIP molded body 610, another CIP molded body 610 is stacked on top of it. At this time, the thickness of the other CIP molded body 610 can be adjusted so that the electrode 120 is embedded at a depth of 0.5 mm or more. Next, as shown in Figure 3(d), the CIP molded bodies 610 stacked with the electrode 120 sandwiched in between are hot-pressed to produce a fired body 200. The pressure applied during firing is preferably 1 MPa or more. It is also preferable to fire at a temperature of 1800°C or higher. It is not necessary to produce the fired body 200 in a single firing; a pre-fired body may be produced first, and then the pre-fired body may be further fired to produce the fired body 200.

[0017] Next, a method for separating the ring-shaped ceramic base material 110 from the fired body 200 will be described. In the present embodiment, the ceramic base material 110 was separated by performing water jet machining under the following processing conditions. A nozzle with an inner diameter of 0.25 mm was used, and water containing garnet abrasive (particle size #120) was used as the discharged fluid. During cutting, the discharged liquid was discharged from the nozzle at a discharge pressure of 320 MPa. Also, during hole machining for forming through holes as described later, the discharged liquid was discharged from the nozzle at a discharge pressure of 90 MPa. The temperature of the discharged liquid was set to 70°C, and the nozzle was scanned at a speed of 8.0 mm / min to 10 mm / min. When the distance between the machining surface and the nozzle is small, there is a risk that the machining surface and the nozzle will come into contact. Also, when the distance between the machining surface and the nozzle is large, the water may disperse and sufficient cutting force may not be obtained. Therefore, in the present embodiment, the distance between the machining surface (upper surface) of the fired body 200 and the nozzle was set to 2.0 mm. As a result, it was possible to obtain sufficient cutting force while suppressing the risk of contact between the machining surface and the nozzle.

[0018] As described above, so-called hot press firing is performed when manufacturing the sintered body 200. In this embodiment, as described above, a pressure of 1 MPa or more is applied at a temperature of 1800°C or higher. As a result, residual stress is generated inside the sintered body 200. When attempting to cut and separate the ring-shaped ceramic substrate 110 from the sintered body 200 by conventional machining, the residual stress in the sintered body 200 may cause cracks to form in the ceramic substrate 110 during processing. In this embodiment, by employing water jet processing, the release of residual stress can be slowed compared to machining, and the occurrence of cracks can be suppressed. According to the inventors' findings, it is possible to process the material by scanning the nozzle at a speed of 8.0 mm / min to 10 mm / min while gradually releasing residual stress. This is significantly faster than the conventional machining method used to cut and separate the ring-shaped ceramic substrate 110 from the fired body 200 (for example, MC machining using a grinding wheel takes 10 to 20 hours to process a workpiece with a diameter of 300 mm and a thickness of 20 mm). Furthermore, in this embodiment, the processing allowance when performing waterjet machining can be reduced to about 1.0 mm or less. This is significantly smaller than the processing allowance (about 5 mm to 10 mm) caused by the grinding wheel dimensions when performing machining. The processing allowance can be adjusted from 0.5 mm to 3.0 mm by changing the nozzle. In other words, in this embodiment, by employing waterjet machining, the difference between the inner diameter Φ1 of the ring-shaped ceramic substrate 110 and the outer diameter Φ2 of the disc-shaped portion 230 separated from the fired body 200 could be set to 0.5 mm or more and 3 mm or less.

[0019] Thus, when the process of cutting and separating the ring-shaped ceramic substrate 110 from the fired body 200 is performed by water jet machining, the inner diameter of the ring-shaped ceramic substrate 110 can be machined using water jet machining, and the outer shape can be machined using conventional machining. Alternatively, both the inner diameter and outer shape of the ring-shaped ceramic substrate 110 can be machined using water jet machining. In this case, by performing the outer shape machining before the inner diameter machining using water jet machining, stress is released from the outer circumference of the ceramic substrate 110. This suppresses the occurrence of cracks in the ceramic substrate 110 during inner diameter machining.

[0020] Furthermore, the process of cutting out and separating the ring-shaped ceramic substrate 110 from the fired body 200 can be carried out as follows. As shown in Figure 5, grooves 621 are formed in advance in the region where the inner diameter will be processed later by water jet machining (hereinafter referred to as the separation processing region) and the region where the outer diameter will be processed (hereinafter referred to as the outer diameter processing region) of the CIP molded body 610 (see Figure 3(d)) described above. As shown in Figure 5(b), carbon sheets C are filled into the formed grooves 621. Alternatively, BN powder can be filled into the grooves 621. Next, hot press firing is performed according to the procedure described above to form the fired body 200. Then, water jet machining is performed on the grooves 621 filled with carbon sheets C to remove the filled carbon sheets C (see Figure 5(c)). Furthermore, grinding is performed on the lower surface 211 of the fired body 200 up to the bottom surface of the grooves 621. This makes it possible to cut out and separate the ring-shaped ceramic substrate 110 from the fired body 210. In this case, since firing is performed with the carbon sheet C filled in the groove 621, the residual stress in the fired body 200 can be reduced, and the occurrence of cracks during processing can be suppressed. Furthermore, compared to waterjet machining the AlN ceramic portion of the fired body 200, removing the carbon sheet C filled in the groove 621 by waterjet machining is easier and allows for an increase in processing speed.

[0021] Alternatively, after manufacturing the fired body 200 using the procedure described above, multiple through holes 625 can be formed further inside the separated processing area before the inner diameter of the ring-shaped ceramic substrate 110 is processed by water jet processing (see Figure 6). The through holes 625 can also be formed in the calcined body or CIP molded body before the main firing. For example, 12 through holes 625 can be formed at 30° intervals. The number of through holes 625 is not limited to 12 and can be any number as appropriate. For example, 6 through holes 625 may be formed at 60° intervals, or 3 may be formed at 120° intervals. Furthermore, the through holes do not necessarily have to penetrate the fired body 200, and may be closed holes. In this case, it is preferable that the depth of the closed hole is at least half the thickness of the fired body 200.

[0022] In the above description, the multiple through holes 625 were formed in a region of the fired body 200 that was further inside the separation processing section, which is the area where the inner diameter is processed by water jet machining. However, one of the multiple through holes 625 can be placed in the separation processing section, making the through hole 625 the starting point for inner diameter machining. This reduces the impact force and stress concentration that occur at the starting point of machining, and suppresses the occurrence of cracks.

[0023] Furthermore, various water jet machining methods described above may be combined. For example, the fired body 200 may be manufactured with grooves 621 pre-formed in the separation machining section and the outer diameter machining section and filled with carbon sheets, and further, multiple through holes 625 may be formed on the inside of the separation machining section. This makes it possible to suppress crack occurrence even more than when the various water jet machining methods described above are performed individually.

[0024] Alternatively, when manufacturing the fired body 200, a disc-shaped core 700 with an outer diameter of Φ2 or less can be placed in the inner region (hereinafter simply referred to as the inner region) of the part that will become a ring-shaped ceramic base material 110 with an inner diameter of Φ1 after firing. The core 700 can be made of alumina, AlN ceramics, carbon, etc. Specifically, as shown in Figure 7, the core 700 is placed in the inner region. At this time, a carbon sheet C is wrapped around the outside of the core 700. Then, the fired body 200 is manufactured with the core 700 and carbon sheet C placed in the inner region. After that, the carbon sheet C is removed by water jet processing and the core 700 is removed. Then, the outer shape of the fired body 200 can be processed by water jet processing or machining to form the ring-shaped ceramic base material 110. In this case, the amount of granulated powder P used in the portion corresponding to the volume of the core 700 can be reduced, which can contribute to cost reduction.

[0025] Furthermore, when producing the fired body 200, the CIP molded body 610 can be hot-pressed in a multi-layered state, as shown in Figure 8(a). Alternatively, as shown in Figure 8(b), the CIP molded body 610 can be hot-pressed in a multi-layered state with a core 700 placed in the inner region. In either case, compared to hot-pressing the CIP molded body 610 in a single layer, the number of fired bodies 200 produced in one firing can be increased, and manufacturing costs can be reduced.

[0026] <Effects of the Embodiment> In the above embodiment, manufacturing a ring heater 100 with an inner diameter of Φ1 involves preparing a plate-shaped fired body 200 containing an electrode 120, and separating a disc-shaped portion with an outer diameter of Φ2 (Φ1 > Φ2) from the fired body 200 by water jet processing. By performing water jet processing when separating the disc-shaped portion with an outer diameter of Φ2 (Φ1 > Φ2) from the fired body 200, the release of residual stress in the fired body 200 can be slowed compared to machining, thereby suppressing the occurrence of cracks. Furthermore, while slowing the release of residual stress, it is possible to process by scanning the nozzle at a speed of 8.0 mm / min to 10 mm / min, so the processing can be done at a sufficiently faster speed compared to normal machining.

[0027] In the above embodiment, a groove 621 is formed in the separation processing portion of the plate-shaped fired body 200, which is processed by water jet, and the groove 621 is filled with carbon sheet C or BN powder. In this case, water jet processing is performed on the groove 621 filled with carbon sheet C or BN powder, the filled carbon sheet C or BN powder is removed, and the lower surface 211 of the fired body 200 is ground down to the bottom surface of the groove 621. This makes it possible to easily cut and separate the ring-shaped ceramic base material 110 from the fired body 210. Since firing is performed with the groove 621 filled with carbon sheet C or BN powder, residual stress in the fired body 200 can be reduced, and the occurrence of cracks during processing can be suppressed. Furthermore, compared to water jet processing the AlN ceramic portion of the fired body 200, removing the carbon sheet C or BN powder filled in the groove 621 by water jet processing is easier and allows for an increase in processing speed.

[0028] In the above embodiment, multiple through holes 625 (or blind holes) are formed in the plate-shaped fired body 200 at a location inside the separation processing section processed by a water jet, or at a location inside the processing separation section. In this case, by forming through holes 625 (or blind holes) in the fired body 200, residual stress remaining in the fired body 200 can be reduced. Furthermore, one of the multiple through holes 625 (or blind holes) can be placed in the separation processing section to serve as the starting point for internal diameter processing. This reduces impact force and stress concentration that occur at the starting point of processing, thereby suppressing the occurrence of cracks.

[0029] In the above embodiment, when cutting and separating the ring-shaped ceramic substrate 110 from the plate-shaped fired body 200, both the inner diameter processing and the outer shape processing can be performed by water jet processing. In this case, by performing water jet processing on the outer shape processing before the inner diameter processing, stress is released on the outer circumference of the ceramic substrate 110. This suppresses the occurrence of cracks in the ceramic substrate 110 during inner diameter processing.

[0030] <Change form> The embodiments described above are merely illustrative and can be modified as appropriate. For example, the ceramic substrate 110 does not necessarily have to be made of AlN ceramics. For example, the ceramic substrate 110 can be made of a ceramic sintered body of silicon carbide, alumina, silicon nitride, etc. Also, the shape, thickness, material, etc. of the electrode 120 placed inside the ceramic substrate 110 can be changed as appropriate. Furthermore, the electrode 120 is not limited to a heater electrode. For example, it may be an electrostatic adsorption electrode or a high-frequency electrode.

[0031] In the above embodiment, no electrodes were placed in the inner region of the ring-shaped ceramic substrate 110 of the fired body 200. However, the present invention is not limited to such an embodiment, and electrodes 130 may be built into the inner region of the ring-shaped ceramic substrate 110 of the fired body 200 (see Figure 9). That is, when the ring-shaped ceramic substrate 110 with an inner diameter Φ1 and the disc-shaped portion 230 with an outer diameter Φ2 are separated from the fired body 200 by water jet processing, electrodes 130 may be built into the disc-shaped portion 230 with an outer diameter Φ2. In this case, since the processing allowance can be adjusted from 0.5 mm to 3.0 mm in water jet processing, the difference between the inner diameter Φ1 of the ring-shaped ceramic substrate 110 and the outer diameter Φ2 of the disc-shaped portion 230 separated from the fired body 200 can be set to 0.5 mm or more and 3 mm or less.

[0032] In the above embodiment, water jet processing was used as an example, but the processing method applicable to the present invention is not limited to water jet processing, and water laser processing can be applied instead. In water laser processing, laser light is introduced into the water jet, and the laser light is guided to the processing surface by totally reflecting the laser light at the interface. As a result, focusing of the laser light is unnecessary, and the cutting width can be adjusted by changing the nozzle diameter. In addition, the cooling effect of water can suppress the heat effect caused by the irradiation of the laser light. Furthermore, it is possible to remove foreign matter from the processed area by the water flow.

[0033] Although embodiments and modified versions of the invention have been described above, the technical scope of the present invention is not limited to the scope described above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the above embodiments. It is also clear from the claims that such modified or improved forms may be included in the technical scope of the present invention.

[0034] The order in which each process in the manufacturing method shown in the specification and drawings is executed is not specifically defined, and unless the output of a previous process is used in a later process, the processes can be executed in any order. Even if phrases such as "first," and "next," are used for convenience, this does not mean that the processes must be performed in that order. [Explanation of Symbols]

[0035] 100 Ring Heater 110 Ceramic substrate 120, 130 electrodes 200 fired bodies

Claims

1. Inner diameter Φ １ A method for manufacturing a ceramic electrode embedding member having an annular shape, The process involves preparing a plate-shaped ceramic firing body with an electrode embedded in it, From the aforementioned plate-shaped ceramic fired body, the outer diameter Φ ２ (Φ １ >Φ ２ A method for manufacturing a ceramic electrode embedded member, comprising the steps of separating the disc-shaped portion of a ceramic electrode using a water jet or water laser.

2. The process of preparing the plate-shaped ceramic fired body is as follows: This includes incorporating another electrode into the disc-shaped portion that is separated by a water jet or water laser, The inner diameter Φ １ and the outer diameter Φ ２ A method for manufacturing a ceramic electrode embedded member according to claim 1, wherein the difference is 0.5 mm or more and 3 mm or less.

3. The process of preparing the plate-shaped ceramic fired body is as follows: Grooves are formed in the separation processing portion of the aforementioned ceramic firing body, which is processed by a water jet or water laser. A method for manufacturing a ceramic electrode embedded member according to claim 1, comprising filling the groove with a carbon sheet or BN powder.

4. The process of preparing the plate-shaped ceramic fired body is as follows: A method for manufacturing a ceramic electrode embedded member according to claim 1, comprising forming a plurality of through holes or a plurality of bottomed holes in the separated portion of the ceramic fired body, or in a position inside the separated portion, which is processed by a water jet or water laser.

5. The outer diameter of the ceramic electrode embedding member is Φ ３ And, Furthermore, the outer diameter Φ ２ Before the step of separating the following disc-shaped portion by a water jet or a water laser, from the plate-shaped ceramic fired body, an outer diameter Φ ３ The method for manufacturing a ceramic electrode-embedded member according to claim 1, including a step of separating a disc-shaped portion having a diameter of Φ or more by a water jet or a water laser.

6. The process of preparing the plate-shaped ceramic fired body is as follows: The above electrode is incorporated, with an inner diameter of Φ １ The following annular ceramic molded body and an outer diameter Φ disposed inside the annular ceramic molded body ２ A method for manufacturing a ceramic electrode embedded member according to claim 1, comprising the step of firing the set of the annular ceramic molded body and the core while the disc-shaped core is combined with the annular ceramic molded body.

7. The process of preparing the plate-shaped ceramic fired body is as follows: A method for manufacturing a ceramic electrode embedded member according to claim 1, comprising firing a plurality of ceramic molded bodies, each containing the aforementioned electrode, in a stacked state.

8. The process of preparing the plate-shaped ceramic fired body is as follows: A method for manufacturing a ceramic electrode embedded member according to claim 6, comprising firing a plurality of sets of the annular ceramic molded body and the core in a stacked state.

9. Inner diameter Φ １ A first ceramic electrode embedding member having an annular shape, Outer diameter Φ ２ It comprises a second ceramic electrode embedding member having a disc-shaped form, The first ceramic electrode embedding member and the second ceramic electrode embedding member are integrally fired. The outer diameter Φ of the second ceramic electrode embedding member ２ The inner diameter Φ of the first ceramic electrode embedding member is １ A set of ceramic heater electrode embedding members characterized by being 0.5 mm to 3 mm smaller than [a certain standard].

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