Ceramic susceptor

Abstract

To provide a technique for suppressing concentration of stress at a corner of a flow path.SOLUTION: A cross-sectional shape in a cross section perpendicular to a longitudinal direction of a flow path 112 has a substantially rectangular shape having an upper side 113a, a lower side 113b, and a pair of sides 113c, and a substantially fan-shaped curved portion 114 protruding outward is provided at four corner portions. An intersection X of an imaginary line L1 extending the upper side 113a and an imaginary line L2 extending the side 113c is surrounded by the curved portion 114. The curved portion 114 is also a gently continuous curve.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a ceramic susceptor. [Background technology]

[0002] Patent Document 1 discloses an electrostatic chuck as an example of a ceramic susceptor having a wafer mounting surface for holding a substrate such as a wafer. The electrostatic chuck described in Patent Document 1 is manufactured by stacking and firing a plurality of green sheets, including a green sheet having holes that form flow paths. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-96336 Summary of the Invention [Problem to be solved by the invention]

[0004] When stacking the green sheets, a pressure is applied to the green sheets in the thickness direction. Because the green sheets have high plasticity, when the stacked green sheets are pressed during firing, they deform so as to bulge convexly toward the inside of the grooves. As a result, the cross section of the flow path formed inside is deformed so that all sides of the flow path are concave toward the inside of the flow path. Therefore, at the corners of the flow path, the upper wall surface defining the upper surface of the flow path and the side wall surface defining the side surface intersect at an acute angle. Therefore, the flow rate and flow velocity of the fluid flowing near the corners of the flow path are suppressed, and stress is concentrated at the corners of the flow path.

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a technology that can increase the flow rate and flow velocity of a fluid flowing near the corner of a flow path, while suppressing stress concentration at the corner of the flow path. [Means for solving the problem]

[0006] According to an aspect of the present invention, a ceramic sintered body is provided which has an upper surface and a lower surface facing the upper surface in a vertical direction, and has a flow path formed therein extending in a longitudinal direction intersecting the vertical direction, The cross-sectional shape of the flow channel in a cross section perpendicular to the longitudinal direction is the upper edge is parallel to the upper surface, the lower edge is opposite to the upper edge in the vertical direction, and a pair of side edges are opposite to each other in a width direction intersecting the vertical direction and the longitudinal direction between the upper edge and the lower edge in the vertical direction; and the four corners are included; Of the four corners, two corners located between the top edge and the pair of side edges protrude outward to surround the intersection of the top edge and the pair of side edges when extended, and are characterized by gently continuing curves. [Effects of the Invention]

[0007] According to the configuration of the present invention, the corners of the flow path have curved portions, which allows the surface area of ​​the corners to be larger than when the corners do not have curved portions. Increasing the surface area of ​​the corners allows the flow rate and flow velocity of the fluid flowing near the corners to be increased. This improves the heat absorption capacity of the ceramic susceptor, allowing efficient heat absorption from the wafer placed on the ceramic susceptor. Furthermore, the curved portions at the corners of the flow path alleviate stress concentration at the corners of the flow path. Furthermore, the flow velocity of the fluid can be ensured at the corners of the flow path, allowing for a homogenous temperature distribution on the upper surface of the ceramic susceptor. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a ceramic susceptor 100. As shown in FIG. [Figure 2] FIG. 2 is a schematic explanatory diagram of the ceramic susceptor 100. As shown in FIG. [Figure 3]FIG. 3 is a flowchart showing a method for manufacturing the SiC composite material 110. [Figure 4] 10(a) to 10(d) are diagrams showing the flow of another method for producing the SiC composite material 110. FIG. [Figure 5] (a) is an explanatory diagram for explaining the joining of a calcined body of a lower plate 130 having a groove 124 with a rectangular cross section formed on its upper surface 131 with a calcined body of an upper plate 120, (b) is an explanatory diagram for explaining the cross section of a flow path 112 formed inside a SiC composite material 110, and (c) is an enlarged view for explaining the cross section of the flow path 112. [Figure 6] FIG. 6 is an explanatory diagram illustrating an SiC composite material 910 produced by stacking three layers of green sheets and firing them. [Figure 7] FIG. 7 is an explanatory diagram for explaining the longitudinal direction of the flow channel 112. As shown in FIG. [Figure 8] FIG. 10 is an explanatory diagram for explaining another aspect of the flow channel 112. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Ceramic susceptor 100> The ceramic susceptor 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. The ceramic susceptor 100 according to the present embodiment is used, for example, as a stage for holding a semiconductor wafer such as a silicon wafer (hereinafter simply referred to as wafer 10) inside a semiconductor manufacturing apparatus. In that case, for example, an electrostatic chuck, a heater plate, etc. are arranged on the ceramic susceptor 100. Further, as will be described later, an electrode 140 (see FIG. 2) may be embedded in the ceramic susceptor 100 itself. In that case, the ceramic susceptor 100 can also be used as a heater for heating the wafer 10. In the following description, the vertical direction 5 is defined based on the state in which the ceramic susceptor 100 is installed so as to be usable (the state in FIG. 1). As shown in FIG. 1, the ceramic susceptor 100 according to the present embodiment includes a plate-shaped SiC composite material 110 having a flow path 112 (see FIG. 2) formed inside, and an electrode 140 (see FIG. 2). The SiC composite material 110 is an example of the ceramic sintered body of the present invention.

[0010] <SiC composite material 110> The SiC composite material 110 is formed of SiC-containing SiC ceramics and has a circular plate shape. In the present embodiment, the SiC composite material 110 is a ceramic sintered body containing SiC and has a thermal conductivity of 75 W / mk or more. Since SiC ceramics have high resistance to water, water can be flowed as a cooling fluid through the flow path 112 formed inside. Water has a high thermal conductivity and is suitable when absorbing a large amount of heat. The ceramic sintered body containing SiC can be made into a SiC composite material by further containing metal borides, metal carbides, metal nitrides, etc. in addition to sintering aids such as B4C, C, Y2O3, etc. added to SiC. For example, as the metal boride, borides of metals in Groups 4 to 6 of the periodic table can be used. Although there is no particular limitation on the size of the SiC composite material 110, it can be set to a diameter of 150 mm or more and a thickness of 20 mm to 50 mm from the use as a substrate holding member for a semiconductor manufacturing apparatus.

[0011] As shown in FIG. 2, a hollow flow path 112 is formed inside the SiC composite material 110. As will be described later, the SiC composite material 110 is formed by bonding an upper plate 120 and a lower plate 130 (see FIG. 2) together. Note that in FIGS. 1 and 2, for convenience of explanation, the boundary between the upper plate 120 and the lower plate 130 is illustrated by a solid line. By forming a groove 124 on at least one of the lower surface 122 (the surface facing the lower plate 130) of the upper plate 120 and the upper surface 131 (the surface facing the upper plate 120) of the lower plate 130, and then bonding the upper plate 120 and the lower plate 130 in an overlapping state, the hollow flow path 112 can be formed inside the SiC composite material 110. Note that the planar shape of the flow path 112 can be any shape. For example, the flow path 112 may have a substantially spiral shape when viewed from above. The cross-sectional shape of the flow path 112 will be described later. In order to ensure a sufficient flow rate and volume of the cooling fluid, the height (length in the vertical direction) and width (length in the direction perpendicular to the vertical direction in a vertical plane) of the flow channel 112 are preferably 2 mm or more, and more preferably 10 mm or more. In order to reduce the flow channel resistance of the flow channel 112, the center line average roughness Ra of the inner surface of the flow channel 112 is preferably 0.8 μm or less, more preferably 0.4 μm or less, and even more preferably 0.2 μm or less. As will be described later, in this embodiment, the grooves 124 are formed by machining (grinding) the calcined body or sintered body, so that the center line average roughness Ra can be easily adjusted.

[0012] <Electrode 140> As shown in FIG. 2, an electrode 140 is embedded in the upper plate 120 at a position 0.05 mm or more below the upper surface 121. As shown in FIG. 2, the electrode 140 is a metal mesh or foil cut into a strip shape. The outer diameter of the electrode 140 is slightly smaller than that of the upper plate 120, and the electrode 140 is not exposed from the side of the upper plate 120. A terminal portion 141 to be connected to a power supply line (not shown) is provided approximately in the center of the electrode 140. The electrode 140 is formed of a heat-resistant metal (high-melting point metal) such as a mesh or foil woven with wires of tungsten (W), molybdenum (Mo), molybdenum and / or an alloy containing tungsten. The purity of the tungsten and molybdenum is preferably 99% or more. The thickness of the electrode 140 is 0.15 mm or less. From the viewpoint of increasing the resistance value of the electrode 140 and reducing current consumption, the wire diameter is preferably 0.1 mm or less, and the thickness of the electrode 140 is preferably 0.1 mm or less. Furthermore, the width of the strip-shaped electrode 140 is preferably 2.5 mm to 20 mm, and more preferably 5 mm to 15 mm. In this embodiment, the electrode 140 is cut into the shape shown in FIG. 2 , but the shape of the electrode 140 is not limited thereto and may be modified as appropriate. In addition to or instead of the electrode 140, an electrostatic attraction electrode or a plasma electrode for generating plasma above the SiC composite material 110 may be embedded inside the upper plate 120. Furthermore, the electrode 140 does not necessarily have to be embedded in the upper plate 120. For example, the electrode 140 may be embedded in the lower plate 130. Alternatively, the electrode 140 may be embedded in both the upper plate 120 and the lower plate 130.

[0013] <Method for manufacturing ceramic susceptor 100> Next, we will explain a method for manufacturing the ceramic susceptor 100. The method for manufacturing the ceramic susceptor 100 includes producing an upper plate 120 and a lower plate 130 each containing SiC as a component, and joining the upper plate 120 and the lower plate 130 together.

[0014] A method for producing the upper plate 120 and the lower plate 130 will be described with reference to FIG. 3. First, 4 wt % or less of sintering aids (B4C, C) are added to the SiC raw material powder as needed. Metal boride can also be added to the SiC raw material powder. Next, a PVA (polyvinyl alcohol) binder is added to the SiC raw material powder, and the mixture is mixed in ethanol, dried, and then granulated to produce granulated powder Q containing SiC as a component (S101). When producing the granulated powder Q, the sintering aid addition rate can be the same for the granulated powder Q for producing the upper plate 120 and the granulated powder Q for producing the lower plate 130, but can also be different.

[0015] Next, the granulated powder Q is filled into a rubber mold and isostatically pressurized (CIP) using water pressure to produce a CIP molded body that will become the upper plate 120 and a CIP molded body that will become the lower plate 130 (S102). For example, CIP molding can be performed at a pressure of 130 MPa. Next, the CIP molded body is degreased to remove the binder. The degreased CIP molded body is then heat-treated in a vacuum atmosphere at a temperature of 1500°C for two hours, and then fired in an Ar atmosphere at a temperature of 2000°C or higher for three hours at atmospheric pressure (S103). Alternatively, the CIP molded body may be placed in a carbon mold with a floor 601 (see FIG. 4) and hot-press fired while pressed with a punch 602. For example, hot-press firing can be performed in an Ar atmosphere at a temperature of 2000°C or higher for three hours (S103). Note that the firing time is not necessarily limited to three hours. The firing time is preferably from 0.1 to 10 hours, and more preferably from 1 to 5 hours.

[0016] Next, the sintered body is subjected to external shaping (S104) to produce the upper plate 120 and the lower plate 130. At this time, grooves 124 (see FIG. 2), which will later become the flow paths 112, are formed in the upper surface 131 of the lower plate 130 and / or the lower surface 122 of the upper plate 120. Note that the grooves 124 do not necessarily have to be formed in the sintered body. Before sintering the CIP molded body, the CIP molded body can be calcined at a temperature lower than the sintering temperature (for example, a temperature 500°C to 100°C lower than the sintering temperature) to produce a calcined body, and the grooves 124 can be formed in the calcined body. Alternatively, the grooves 124 can be formed in the CIP molded body, and after calcining the CIP molded body with the grooves 124 formed therein, additional processing can be performed on the calcined body so that the grooves 124 have the desired dimensions.

[0017] When the electrode 140 is embedded in the upper plate 120, two CIP molded bodies that will become the upper plates 120 are produced, and fired bodies (or calcined bodies) of the two upper plates 120 are produced. Then, a recess (not shown) for embedding the electrode 140 is formed in at least one of the fired bodies (or calcined bodies) of the two upper plates 120. Then, by stacking the two upper plates 120 with the electrode 140 placed in the recess, it is possible to produce the upper plate 120 with the electrode 140 embedded therein.

[0018] In the above description, CIP molded bodies of the upper plate 120 and the lower plate 130 were fabricated and then fired. The present invention is not necessarily limited to fabricating CIP molded bodies. For example, the upper plate 120 and the lower plate 130 can be fabricated using the method described below. As shown in FIG. 4(a), granulated powder P primarily composed of SiC powder is placed in a carbon mold with a floor 601 and pre-pressed with a punch 602. It is preferable that the granulated powder P contains a sintering aid. Next, as shown in FIG. 4(b), an electrode 140 cut to a predetermined shape is placed on the pre-pressed granulated powder P. The electrode 140 is placed parallel to a plane perpendicular to the pressure direction (the bottom surface of the mold with a floor 601). At this time, a W pellet or a Mo pellet may be embedded at the position of the terminal 141 (see FIG. 2) of the electrode 140.

[0019] As shown in FIG. 4(c), granulated powder P is further poured into bed-type mold 601 so as to cover electrode 140, and is pressed and molded with punch 602. Next, as shown in FIG. 4(d), granulated powder P with electrode 140 embedded therein is fired in a pressed state. The pressure applied during firing is preferably 1 MPa or more. Also, firing is preferably performed at a temperature of 1800°C or more. The external processing after firing is the same as described above, and therefore will not be described here. Note that, as in the above description, a calcined body can be produced and the above-described external processing can be performed on the calcined body.

[0020] Next, a method for bonding the upper plate 120 and the lower plate 130 will be described. The upper plate 120 and the lower plate 130 can be bonded by diffusion bonding at a temperature of 1500°C or higher and a pressure of 1 MPa or higher. In this case, it is not necessary to interpose a bonding material between the upper plate 120 and the lower plate 130. The absence of a bonding material means that no bonding layer is visible under an optical microscope (magnification of approximately 500x). Therefore, the upper plate 120 and the lower plate 130 can be bonded in a state of direct contact. When bonding the upper plate 120 and the lower plate 130 by diffusion bonding, the centerline average roughness Ra of the bonding surfaces before bonding is preferably 0.2 μm or less, and more preferably 0.1 μm or less. The above bonding method can be applied to bonding calcined bodies in addition to bonding sintered bodies. In this case, the bonding temperature is higher than the calcination temperature and equivalent to the firing temperature, and bonding and firing are performed simultaneously.

[0021] The upper plate 120 and the lower plate 130 can be joined by hard brazing. A hard brazing material is a brazing material having a melting point (including liquidus temperature and glass transition temperature) of 450°C or higher. By heating the upper plate 120 and the lower plate 130 with the hard brazing material interposed between them to a temperature of 450°C or higher, the upper plate 120 and the lower plate 130 can be joined by the fluidized or molten hard brazing material. At this time, the heat joining is performed under a load of 0.001 MPa or higher. The atmosphere can be appropriately selected from air, inert gas, and vacuum. Examples of hard brazing materials that can be used include silver brazing (BAg-8, melting point 780°C), aluminum brazing (A4047, eutectic point 577°C), gold brazing (BAu-4, liquidus temperature 950°C), and nickel brazing (BNi-2, liquidus temperature 1000°C). These brazing filler metals may contain active metals such as Ti, Hf, and Zr. Metal foils such as Al foils can also be used as brazing filler metals. When joining the upper plate 120 and the lower plate 130 by brazing, it is preferable that the center line average roughness Ra of the joining surfaces before joining be 1.6 μm or less.

[0022] The upper plate 120 and the lower plate 130 can be joined by soft soldering. Soft solder is a brazing material having a melting point (including liquidus temperature and glass transition temperature) below 450°C. By heating the upper plate 120 and the lower plate 130 with the soft solder material interposed between them to a temperature below 450°C, the upper plate 120 and the lower plate 130 can be joined by the fluidized or molten soft solder material. At this time, the heat joining is performed under a load of 0.001 MPa or more. The atmosphere can be selected from air, inert gas, and vacuum. Examples of the soft solder material that can be used include In, Sn, Pb, and alloys (solder) thereof. When joining the upper plate 120 and the lower plate 130 by soft soldering, it is preferable that the centerline average roughness Ra of the joining surfaces before joining be 1.6 μm or less.

[0023] The method for joining the upper plate 120 and the lower plate 130 is not limited to the above-mentioned diffusion bonding, hard solder bonding, and soft solder bonding, but known anodic bonding or the like can also be used.

[0024] Next, a cross section of the flow path 112 formed in the SiC composite 110 of the ceramic susceptor 100 manufactured by the above-described manufacturing method will be described. In the following description, the cross-sectional shape of the flow path 112 will be considered when a calcined body of the lower plate 130 having grooves 124 formed on its upper surface 131 and a calcined body of the upper plate 120 having grooves 124 formed on its lower surface 122 are joined together as shown in Fig. 5(a). Note that the same applies when sintered bodies are joined instead of calcined bodies, and therefore a description thereof will be omitted.

[0025] As shown in Figure 5(a), a groove 124 is formed on the lower surface 122 of the upper plate 120 and the upper surface 131 of the lower plate 130, and has a cross section that is approximately rectangular and has approximately fan-shaped curved portions 114 that protrude outward at the corners.

[0026] When a calcined body of the lower plate 130 and a calcined body of the upper plate 120, each having a groove 124 shaped as shown in FIG. 5(a), are joined together, a flow path 112 shaped as shown in FIG. 5(b) is formed inside the SiC composite material 110. The cross section of the flow path 112 has a generally rectangular shape with an upper edge 113a, a lower edge 113b, and a pair of side edges 113c, and further has generally fan-shaped curved portions 114 protruding outward at the four corners. As shown in FIG. 5(c), the intersection X between an imaginary line L1 extending from the upper edge 113a and an imaginary line L2 extending from the side edge 113c is surrounded by the curved portion 114. Also, as shown in FIG. 5(c), the upper edge 113a of the cross section of the flow path 112 bulges inward of the flow path 112. Furthermore, side edges 113c of the cross section of flow channel 112 have a shape that bulges outward from flow channel 112 on both sides in the width direction of flow channel 112, which is perpendicular to the up-down direction. In the above embodiment, the straightness of the side wall surfaces of flow channel 112 per 10 mm in the up-down direction in the cross section of flow channel 112 is 0.05 mm or more and 1.0 mm or less. Furthermore, the straightness of the top wall surface of flow channel 112 per 10 mm in the width direction in the cross section of flow channel 112 is 0.05 mm or more and 1.0 mm or less.

[0027] In contrast, consider a conventional method of producing a SiC composite 910 by stacking three layers of ceramic green sheets (hereinafter simply referred to as green sheets) and firing them (see FIG. 6). For example, a through groove 924 serving as a flow path 912 may be formed in the center green sheet of the three green sheets, and two green sheets may be stacked from above and below to close the through groove 924, thereby producing a SiC composite 910 having the flow path 912 formed therein. When the three green sheets are simply stacked, the cross section of the flow path 912 formed inside the SiC composite 910 by the through groove 924 is rectangular. However, when the stacked green sheets are fired, a pressing force is applied to the green sheets in the thickness direction (vertical direction), which significantly deforms the cross section of the flow path 912 formed inside the SiC composite 910. This is because the green sheets have low rigidity. Specifically, the cross section of the flow channel 912 formed inside the SiC composite 910 is deformed so that it convex toward the inside of the flow channel 912 on both sides in the vertical direction and also convex toward the inside of the flow channel 912 on both sides in the width direction of the flow channel 912, which is perpendicular to the vertical direction. In this case, the thickness (length in the width direction) of the wall 915 between two adjacent flow channels 912 in the width direction is greatest at approximately the center in the vertical direction. An upper wall surface 912a that defines the top surface of the flow channel 912 and a side wall surface 912b that defines the side surface intersect at an acute angle and do not form a smoothly connected curved surface.

[0028] <Effects of the embodiment> In the above embodiment, the ceramic susceptor 100 includes a plate-shaped SiC composite material 110 containing SiC as a component. A flow path 112 is formed inside the SiC composite material 110, extending in the longitudinal direction in a plane perpendicular to the up-down direction. When the flow path 112 is not linear but curved, the longitudinal direction of the flow path 112 at a certain position is defined as the tangent direction to a center line 112C (see FIG. 7) of the flow path 112 at that position.

[0029] As shown in Fig. 5(b), the cross section of flow channel 112 perpendicular to the longitudinal direction has a generally rectangular shape having an upper side 113a, a lower side 113b, and a pair of side sides 113c, and furthermore, generally fan-shaped curved portions 114 that protrude outward are provided at the four corners. An intersection X between an imaginary line L1 extending from upper side 113a and an imaginary line L2 extending from side side 113c is surrounded by curved portion 114. Furthermore, curved portion 114 is a gently sloping, continuous curve (see Fig. 5(c)).

[0030] The corners of the flow channel 112 have curved portions 114, which allows the surface area of ​​the corners to be larger than when the curved portions 114 are not provided at the corners. Increasing the surface area of ​​the corners allows the flow rate and flow velocity of the fluid flowing near the corners to be increased. This increases the heat absorption capacity of the ceramic susceptor 100, allowing efficient heat absorption from the wafer 10 placed on the ceramic susceptor 100. In particular, in this embodiment, the curved portions 114 are provided at the two corners where the top edge 113a and the side edge 113c intersect. This allows efficient heat absorption from above the flow channel 112. Furthermore, the curved portions 114 at the corners of the flow channel 112 reduce stress concentration at the corners of the flow channel 112. Furthermore, since the flow velocity of the fluid can be ensured at the corners of the flow channel 112 as described above, the temperature distribution on the upper surface 121 of the ceramic susceptor 100 can be homogenized.

[0031] In the above embodiment, the straightness of the side wall surface of the flow channel 112 per 10 mm in the vertical direction in the cross section of the flow channel 112 is 0.05 mm or more and 1.0 mm or less. Also, in the above embodiment, the straightness of the top wall surface of the flow channel 112 per 10 mm in the width direction in the cross section of the flow channel 112 is 0.05 mm or more and 1.0 mm or less. Limiting the deformation amount of the flow channel 112 within this range can ensure the flow velocity and flow rate of the liquid flowing through the flow channel 112 and contribute to reducing the pressure loss throughout the flow channel.

[0032] In the above embodiment, as shown in Fig. 5(c), the upper side 113a of the cross section of the flow channel 112 is a curve that convexly extends inward of the flow channel 112. Also, the side 113c of the cross section of the flow channel 112 is a curve that convexly extends outward of the flow channel 112 in the width direction of the flow channel 112. In either case, these can be easily formed by forming a groove 124 that has a substantially rectangular cross section as shown in Fig. 5(a).

[0033] In the above embodiment, the width and vertical lengths of the flow path 112 can both be 2.0 mm or more. In this case, the cross-sectional area of ​​the flow path 112 can be made sufficiently large, thereby reducing frictional resistance between the fluid flowing through the flow path 112 and the inner surface of the flow path 112 and reducing pressure loss. This ensures the flow velocity and flow rate of the fluid flowing through the flow path 112.

[0034] In the above embodiment, the center line average roughness Ra of the side surface of the flow channel 112 can be set to 0.8 μm or less. This makes it possible to reduce frictional resistance between the fluid flowing through the flow channel 112 and the inner surface of the flow channel 112, thereby reducing pressure loss. This makes it possible to ensure the flow velocity and flow rate of the fluid flowing through the flow channel 112.

[0035] In the above embodiment, the upper plate 120 and the lower plate 130 can be directly bonded by diffusion bonding without using a bonding agent. In this case, since there is no layer of bonding material between the upper plate 120 and the lower plate 130, no thermal resistance is generated by the bonding layer, and cooling efficiency can be improved.

[0036] In the above embodiment, the SiC composite 110 is a ceramic sintered body containing SiC. As described above, when a SiC composite is formed by stacking and firing green sheets, a pressure is applied to the green sheets in the thickness direction (vertical direction) when stacking the green sheets, and the cross section of the flow path formed inside is significantly deformed after firing. However, in the above embodiment, grooves that become the flow path are formed in the calcined body or sintered body, and then the calcined body or sintered body is bonded. This makes it possible to easily form hollow flow paths with minimal deformation of the cross section of the flow path even inside a ceramic sintered body containing SiC.

[0037] <Modification form> The above-described embodiments and examples are merely illustrative and may be modified as appropriate. For example, the shape and dimensions of the SiC composite 110 are not limited to those of the above-described embodiments and examples and may be modified as appropriate.

[0038] In the above embodiment, the ceramic susceptor 100 includes the SiC composite material 110 formed of SiC ceramics containing SiC as the ceramic sintered body. However, the ceramic sintered body does not necessarily have to be formed of SiC ceramics containing SiC. For example, the ceramic sintered body may be formed of ceramics containing AlN and Al2O3.

[0039] In the above embodiment, the substantially fan-shaped curved portions 114 are provided at all four corners of the flow path 112. However, the present invention is not limited to such an embodiment. Of the four corners of the flow path 112, the curved portions 114 may be provided at the two upper corners formed by the top edge 113a and the pair of side edges 113c.

[0040] The cross-sectional shape of the flow channel 112 is not limited to the shape shown in Figure 5(b). The cross-sectional shape of the flow channel 112 can be changed as appropriate as long as the intersection X between the virtual line L1 extending from the top side 113a and the virtual line L2 extending from the side side 113c is surrounded by the curved portion 114, and the curved portion 114 is a smoothly continuous curve. For example, the cross-sectional shape of the flow channel 112 can be a shape as shown in Figure 8. Even in this case, the cross-sectional shape of the flow channel 112 is such that the intersection X between the virtual line L1 extending from the top side 113a and the virtual line L2 extending from the side side 113c is surrounded by the curved portion 114, and the curved portion 114 is a smoothly continuous curve.

[0041] Although the present invention has been described above using embodiments and modifications thereof, the technical scope of the present invention is not limited to the scope of the above description. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0042] The order of execution of each process in the manufacturing method shown in the specification and drawings is not particularly specified, and the processes may be executed in any order unless the output of a previous process is used in a subsequent process. For convenience, even if a description is made using "first," "next," etc., it does not mean that the processes must be executed in this order. [Explanation of symbols]

[0043] 100 Ceramic susceptor 110 SiC composite 120 Upper Plate 130 Lower plate 140 electrodes

Claims

1. a ceramic sintered body having an upper surface and a lower surface facing the upper surface in a vertical direction, and having a flow path formed therein extending in a longitudinal direction intersecting the vertical direction; The cross-sectional shape of the flow channel in a cross section perpendicular to the longitudinal direction is the upper edge is parallel to the upper surface, the lower edge is opposite to the upper edge in the vertical direction, and a pair of side edges are opposite to each other in a width direction intersecting the vertical direction and the longitudinal direction between the upper edge and the lower edge in the vertical direction; and the four corners are provided; Of the four corners, the two corners located between the top edge and the pair of side edges protrude outward so as to surround the intersection point when the top edge and the pair of side edges are extended, and are gently continuous curves. A ceramic susceptor characterized by:

2. 2. The ceramic susceptor according to claim 1, wherein the pair of side edges are curved in a convex shape outward in the width direction.

3. 2. The ceramic susceptor according to claim 1, wherein the upper and lower sides are curved inwardly convexly in the vertical direction.

4. 4. The ceramic susceptor according to claim 1, wherein the cross-sectional shape of the flow channel has a length in the width direction and a length in the up-down direction both of which are 2.0 mm or more.

5. 5. The ceramic susceptor according to claim 4, wherein the centerline surface roughness Ra of the side surfaces of the flow channel facing each other in the width direction is 0.8 [mu]m or less.

6. 2. The ceramic susceptor according to claim 1, wherein no bonding layer is found on the upper surface and the lower surface of the flow channel of the ceramic sintered body.

Images