Ceramic susceptor

Abstract

A ceramic susceptor is provided that internally includes a purge gas flow path, a vacuum suction path, and a thermocouple insertion path in a single layer without impairing their respective functions. This ceramic susceptor includes a disc-shaped ceramic plate assembly including an upper ceramic plate and a lower ceramic plate, internal electrodes embedded in the ceramic plate assembly, and a purge gas groove, a vacuum suction groove, and a thermocouple insertion groove respectively provided on the joint surface side of the upper ceramic plate or the lower ceramic plate. The ceramic plate assembly has a central zone and an outer peripheral zone. The purge gas groove, the vacuum suction groove, and the thermocouple insertion groove each have a straight portion in the central zone. The angle θ 1 formed between the straight portion of the purge gas groove and the straight portion of the thermocouple insertion groove, and the angle θ 2 formed between the straight portion of the purge gas groove and the straight portion of the vacuum suction groove satisfy 90° < θ 1 < 180°, 135° < θ 2 < 225°, and θ 1 < θ 2 .

Description

Technical Field

[0001] The present disclosure relates to a ceramic susceptor.

Background Art

[0002] In a film forming apparatus or an etching apparatus for a semiconductor manufacturing process, a susceptor is used to support a wafer. As such a susceptor, one including a ceramic plate on which a wafer is placed and a cylindrical ceramic shaft attached to the ceramic plate is widely used. The ceramic plate generally has a configuration in which internal electrodes such as a heater electrode, an RF electrode, and an electrostatic chuck (ESC) electrode are embedded inside a ceramic substrate made of aluminum nitride (AlN) or the like having excellent heat resistance and corrosion resistance.

[0003] As a ceramic plate, one having internal paths such as a purge gas flow path for ejecting a purge gas from the outer periphery or surface of the ceramic plate, a vacuum suction path for enabling vacuum suction on the ceramic plate surface, and a thermocouple insertion path for accommodating a thermocouple for measuring the temperature of the ceramic plate is known.

[0004] Patent Document 1 (Japanese Patent Translation of PCT International Publication No. 2017-527984) discloses a substrate support including a first plate having a plurality of purge gas channels on the back side, a second plate disposed directly below the first plate, and an edge ring surrounding the first plate. In this substrate support, the plurality of purge gas channels extend from a single inlet in the central portion of the first plate to a plurality of outlets in the peripheral portion, and the plurality of purge gas channels have substantially equal flow conductances. This document also discloses that the first plate further includes one or more vacuum grooves or the like disposed on the back side.

[0005] Patent Document 2 (Japanese Patent Application Laid-Open No. 2012-80103) discloses a susceptor including a disc-shaped ceramic plate, a thermocouple accommodation space formed inside the ceramic plate, and a thermocouple accommodated in the thermocouple accommodation space. This ceramic plate is formed by joining a pair of ceramic discs, and the thermocouple accommodation space is constituted by a horizontal groove formed on one or both of the joining surfaces of the pair of ceramic discs.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

[0007] When a ceramic plate is provided with a plurality of types of internal paths such as a purge gas flow path (for example, a purge gas channel as described above), a vacuum suction path (for example, a vacuum groove as described above), and a thermocouple insertion path (for example, a thermocouple accommodation space or a horizontal groove as described above), in order to ensure the functions of the respective internal paths, it is required that different types of internal paths do not intersect. For this reason, as one idea, it is considered to divide these internal paths and arrange them on the first joining surface and the second joining surface of the three-layer ceramic plate to form a two-layer structure. However, this method increases the manufacturing cost. Therefore, it would be convenient if a plurality of types of internal paths could be provided in a single-layer structure along one joining surface of the two-layer ceramic plate. However, there are specific positional constraints and requirements for the purge gas flow path, the vacuum suction path, and the thermocouple insertion path, and it is not easy to realize them in a single-layer structure.

[0008] The inventors have now found that the purge gas groove, the vacuum suction groove, and the thermocouple insertion groove each have a straight portion, and the angle θ formed by the straight portion of the purge gas groove and the straight portion of the thermocouple insertion groove 1and the angle θ formed by the straight portion of the purge gas groove and the straight portion of the vacuum suction groove 2 By making the angle θ satisfy a predetermined relationship, it has been found that a ceramic susceptor can be provided inside that houses a purge gas flow path, a vacuum suction path, and a thermocouple insertion path in one layer without impairing their respective functions.

[0009] Accordingly, an object of the present invention is to provide a ceramic susceptor provided inside with a purge gas flow path, a vacuum suction path, and a thermocouple insertion path so as to be accommodated in one layer without impairing their respective functions.

[0010] According to the present disclosure, the following aspects are provided. [Aspect 1] A disk-shaped ceramic plate assembly including an upper ceramic plate and a lower ceramic plate joined at a joint surface, having a first surface on the side opposite to the joint surface of the upper ceramic plate and a second surface on the side opposite to the joint surface of the lower ceramic plate, At least one internal electrode selected from the group consisting of a heater electrode, an RF electrode, and an ESC electrode, embedded in the ceramic plate assembly, A purge gas groove provided on the joint surface side of the upper ceramic plate or the lower ceramic plate, which forms a purge gas flow path together with the joint surface, A vacuum suction groove provided on the joint surface side of the upper ceramic plate or the lower ceramic plate without intersecting the purge gas groove, which forms a vacuum suction path together with the joint surface, A thermocouple insertion groove provided on the joint surface side of the upper ceramic plate or the lower ceramic plate without intersecting the purge gas flow path and the vacuum suction By path, which forms a thermocouple insertion path together with the joint surface, A ceramic susceptor comprising: When viewed in plan, the ceramic plate assembly has a central zone defined as a circular region in which ceramic shafts should be arranged concentrically, and an outer peripheral zone outside the central zone. The purge gas groove has a straight portion disposed linearly from a purge gas inlet in the central zone toward the outer peripheral zone, and an extending portion that extends from the straight portion in the outer peripheral zone and reaches a plurality of purge gas outlets disposed at an outer peripheral portion of the ceramic plate assembly through one or more selected from the group consisting of branching, refraction, bending, and straight advancement. The vacuum suction groove has a straight portion disposed linearly from a vacuum suction inlet in the central zone toward the outer peripheral zone, and an extending portion that extends from the straight portion in the outer peripheral zone and reaches a plurality of vacuum suction outlets of the ceramic plate assembly through one or more selected from the group consisting of branching, refraction, bending, and straight advancement. The thermocouple insertion groove has a straight portion disposed linearly from a thermocouple insertion inlet in the central zone toward a thermocouple insertion path end located in the outer peripheral zone. An angle θ formed by the straight portion of the purge gas groove and the straight portion of the thermocouple insertion groove 1 and an angle θ formed by the straight portion of the purge gas groove and the straight portion of the vacuum suction groove 2 satisfy the following relationship: 50° < θ 1 < 180°, 135° < θ 2 < 310°, and θ 1 < θ 2 A ceramic susceptor that satisfies the above conditions. [Aspect 2] The ceramic susceptor according to Aspect 1, further comprising a cylindrical ceramic shaft concentrically attached to the central zone on the second surface of the ceramic plate assembly. [Aspect 3] The ceramic susceptor according to Aspect 1 or 2, wherein each path length of the purge gas groove from the purge gas inlet to each of the plurality of purge gas outlets is within ±10% of the average path length of the purge gas groove. [Aspect 4] The path length of each of the vacuum suction grooves from the vacuum suction inlet to each of the plurality of vacuum suction outlets is within ±10% of the average path length of the vacuum suction grooves, the ceramic susceptor according to any one of Aspects 1 to 3. [Aspect 5] The ceramic susceptor according to any one of Aspects 2 to 4, comprising a purge gas supply hole that penetrates the side wall constituting the ceramic shaft and the lower ceramic plate and communicates with the purge gas inlet, whereby the purge gas supply hole, the purge gas inlet, the purge gas groove, and the purge gas outlet together constitute the purge gas flow path. [Aspect 6] The ceramic susceptor according to any one of Aspects 1 to 5, wherein the plurality of purge gas outlets are arranged at equal intervals along the outer peripheral portion of the ceramic plate assembly. [Aspect 7] The ceramic susceptor according to any one of Aspects 1 to 6, further comprising a purge ring that is provided annularly along the outer peripheral edge of the ceramic plate assembly and guides the purge gas discharged from the purge gas outlet to jet from the outer peripheral portion of the first surface, and a gap between the outer peripheral edge of the ceramic plate assembly and the purge ring constitutes a purge gas jet outlet. [Aspect 8] The ceramic susceptor according to any one of Aspects 1 to 7, wherein the upper ceramic plate further comprises a vertical hole that communicates with the first surface from the purge gas outlet, and the vertical hole constitutes a purge gas jet outlet that enables the purge gas to jet from the outer peripheral portion of the first surface. [Aspect 9] The ceramic susceptor according to any one of Aspects 2 to 8, comprising a vacuum suction hole that penetrates the side wall constituting the ceramic shaft and the lower ceramic plate and communicates with the vacuum suction inlet, whereby the vacuum suction hole, the vacuum suction inlet, the vacuum suction groove, and the vacuum suction outlet together constitute the vacuum suction path. [Aspect 10] The ceramic susceptor according to any one of Aspects 1 to 9, wherein the plurality of vacuum suction outlets are arranged rotationally symmetrically with respect to the central axis of the ceramic plate assembly. [Aspect 11] In the internal space of the ceramic shaft, a tubular thermocouple guide is further provided which communicates with the second surface of the ceramic plate assembly at the thermocouple insertion port and guides the insertion of the thermocouple into the thermocouple insertion path, according to any one of Aspects 1 to 10 the ceramic susceptor according to any one of the above. [Aspect 12] The ceramic susceptor according to the aspect, further comprising a thermocouple inserted into the thermocouple insertion path through the thermocouple guide and the thermocouple insertion port. 11 as described in. [Aspect 13] When each of the purge gas groove, the vacuum suction groove, and the thermocouple insertion groove is viewed in a cross section perpendicular to the longitudinal direction of the groove, the height of the central portion of the groove is 0.1 to 3.0 mm, the height of the end portion of the groove is 0.5 to 3.0 mm, the width of the groove is 2.0 to 10.0 mm, the ratio of the height of the end portion of the groove to the height of the central portion of the groove is 0.2 to 1.0, the ceramic susceptor according to any one of Aspects 1 to 12.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0012] The ceramic susceptor according to the present invention is a ceramic table for supporting a wafer, which is used in a film forming apparatus or an etching apparatus, particularly a film forming apparatus or an etching apparatus for a semiconductor manufacturing process. For example, the ceramic susceptor according to the present invention may be a ceramic heater for a semiconductor film forming apparatus, or an electrostatic chuck for a semiconductor etching apparatus. Alternatively, it may be an electrostatic chuck heater having both a heater function and an electrostatic chuck function. Typical examples of the film forming apparatus include CVD (Chemical Vapor Deposition) apparatuses (e.g., thermal CVD apparatuses, plasma CVD apparatuses, photo CVD apparatuses, and MOCVD apparatuses) and PVD (Physical Vapor Deposition) apparatuses.

[0013] Figs. 1 to 3 show an example of a ceramic susceptor. The ceramic susceptor 10 shown in Figs. 1 to 3 includes a ceramic plate assembly 12, internal electrodes 14, a purge gas groove 16, a vacuum suction groove 18, and a thermocouple insertion groove 20. The ceramic plate assembly 12 has a disc shape and includes an upper ceramic plate 12a and a lower ceramic plate 12b joined to each other at a joining surface 12c. The ceramic plate assembly 12 has a first surface 12d on the side opposite to the joining surface 12c of the upper ceramic plate 12a and a second surface 12e on the side opposite to the joining surface 12c of the lower ceramic plate 12b. The internal electrode 14 is at least one selected from the group consisting of a heater electrode, an RF electrode, and an ESC electrode, and is embedded in the ceramic plate assembly 12. The purge gas groove 16 is a groove that forms a purge gas flow path together with the joining surface 12c, and is provided on the joining surface 12c side of the upper ceramic plate 12a or the lower ceramic plate 12b. The vacuum suction groove 18 is a groove that forms a vacuum suction path together with the joining surface 12c, and is provided on the joining surface 12c side of the upper ceramic plate 12a or the lower ceramic plate 12b without intersecting the purge gas groove 16. The thermocouple insertion groove 20 is a groove that forms a thermocouple insertion path together with the joining surface 12c, and is provided on the joining surface 12c side of the upper ceramic plate 12a or the lower ceramic plate 12b without intersecting the purge gas flow path and the vacuum suction ByIt is provided without intersecting the road. The ceramic plate assembly 12 has a central zone Z1 and an outer peripheral zone Z2. The central zone Z1 is defined as a circular region in which the ceramic shafts 22 should be arranged concentrically when viewed in plan, and the outer peripheral zone Z2 is the region outside the central zone Z1. The purge gas groove 16 has a straight portion 16a and an extending portion 16b. The straight portion 16a of the purge gas groove 16 is linearly arranged from the purge gas inlet 16c in the central zone Z1 toward the outer peripheral zone Z2. The extending portion 16b of the purge gas groove 16 extends from the straight portion 16a in the outer peripheral zone and reaches a plurality of purge gas outlets 16d arranged at the outer peripheral portion of the ceramic plate assembly 12 through one or more selected from the group consisting of branching, refraction, bending, and straight advancement. The vacuum suction groove 18 also has a straight portion 18a and an extending portion 18b. The straight portion 18a of the vacuum suction groove 18 is linearly arranged from the vacuum suction inlet 18c in the central zone Z1 toward the outer peripheral zone Z2. The extending portion 18b of the vacuum suction groove 18 extends from the straight portion 18a in the outer peripheral zone Z2 and reaches a plurality of vacuum suction outlets 18d of the ceramic plate assembly 12 through one or more selected from the group consisting of branching, refraction, bending, and straight advancement. The thermocouple insertion groove 20 has a straight portion 20a, and the straight portion 20a is linearly arranged from the thermocouple insertion port 20b in the central zone Z1 toward the thermocouple insertion path end 20c located in the outer peripheral zone Z2. In such a configuration, the angle θ formed by the straight portion 16a of the purge gas groove 16 and the straight portion 20 a of the thermocouple insertion groove 1 , and the angle θ formed by the straight portion 16a of the purge gas groove 16 and the straight portion 18 a of the vacuum suction groove 18 2 are in the following relationship: 50° < θ 1 < 180°, 135° < θ 2 < 310°, and θ 1 < θ 2 are satisfied. By satisfying these relationships, it is possible to provide the ceramic susceptor 10 having therein the purge gas flow path, the vacuum suction path, and the thermocouple insertion path in one layer without impairing their respective functions.

[0014] As described above, when a ceramic plate is provided with a plurality of types of internal paths such as a purge gas flow path, a vacuum suction path, and a thermocouple insertion path, it is required to prevent different types of internal paths from intersecting in order to ensure the functions of each internal path. For this reason, it is conceivable as an idea to form these internal paths in a two-layer structure, but this method increases the manufacturing cost. Therefore, it would be convenient if a plurality of types of internal paths could be provided in a single-layer structure along one joint surface of the two-layer ceramic plate. In this specification, "providing a plurality of types of internal paths in a single-layer structure along one joint surface" means providing the plurality of types of internal paths in any form of an upper internal path having the joint surface as the bottom, a lower internal path having the joint surface as the top, and a combination thereof (i.e., a composite internal path including the position that was the joint surface). However, there are specific positional constraints and requirements for the purge gas flow path, the vacuum suction path, and the thermocouple insertion path respectively, and it is not easy to realize them in a single-layer structure. For example, internal paths tend to be concentrated at the joint portion of the ceramic plate with the ceramic shaft. In that case, the concentrated portion becomes vulnerable, and there is a risk that the ceramic plate may be damaged due to the joint with the ceramic shaft. Also, it is desirable that the purge gas groove has a large number of purge gas outlets on the outer periphery of the ceramic plate. However, if the path lengths to each purge gas outlet are not made as uniform as possible, the uniformity of the process using the ceramic susceptor cannot be maintained. Furthermore, it is desirable that the vacuum suction groove has at least two vacuum suction outlets. However, if the path lengths to each vacuum suction outlet are not made as uniform as possible, the wafer cannot be adsorbed uniformly. Moreover, the thermocouple insertion groove requires a certain length to measure the temperature of the internal electrode on the outer peripheral portion of the ceramic plate. Among such various constraints and requirements, the ceramic susceptor 10 of the present invention can be internally provided so as to be accommodated in a single layer without impairing the functions of the purge gas flow path, the vacuum suction path, and the thermocouple insertion path respectively. By using such a ceramic susceptor 10 in a film-forming process, the functions of the purge gas flow path, the vacuum suction path, and the thermocouple insertion path can be maximally exerted, stable adsorption force and heat uniformity can be realized, and as a result, the film-forming property can be improved.

[0015] From the above viewpoints, the angle θ formed by the straight portion 16a of the purge gas groove 16 and the straight portion 20a of the thermocouple insertion groove 20 1 is such that 50° < θ 1 < 180°, preferably 70° < θ 1 < 170°, more preferably 80° < θ 1 < 160°, still more preferably 90° < θ 1 < 150°, particularly preferably 100° < θ 1 < 140°. From the same viewpoints, the angle θ formed by the straight portion 16a of the purge gas groove 16 and the straight portion 18a of the vacuum suction groove 18 2 is such that 135° < θ 2 < 310°, preferably 145° < θ 2 < 225°, more preferably 155° < θ 2 < 205°, still more preferably 165° < θ 2 < 195°, particularly preferably 175° < θ 2 < 185°. FIGS. 4 and 5 show modified examples of the arrangements of the purge gas groove 16, the vacuum suction groove 18, and the thermocouple insertion groove 20. As can be seen from FIGS. 1, 4, and 5, when the angles θ 1 and θ 2 are regarded as the rotation angles obtained by rotating the straight portion 16a of the purge gas groove 16 about the central axis of the ceramic plate assembly 12, respectively, the angle θ 2 is defined as the rotation angle when rotating in the same rotation direction as the angle θ 1 (i.e., the angle encompassing the entire angle θ 1 ). Therefore, the relationship between θ 1 and θ 2 is that θ 1 < θ 2 and preferably 1.1θ 1 < θ 2 more preferably 1.2θ 1 < θ 2 are satisfied. Therefore, θ 2 is determined to encompass θ 1

[0016] Ceramic plate assembly 12 is ​It includes an upper ceramic plate 12a and a lower ceramic plate 12b joined to each other at a joint surface 12c. The upper ceramic plate 12a and the lower ceramic plate 12b may be made of materials having the same physical properties as each other, or may be made of materials having different physical properties (e.g., volume resistivity and coefficient of thermal expansion) from each other. In the latter case, for example, the volume resistivity of the upper ceramic plate 12a may be made relatively higher than the volume resistivity of the lower ceramic plate 12b, or the volume resistivity of the lower ceramic plate 12b may be made relatively higher than the volume resistivity of the upper ceramic plate 12a. In any case, the upper ceramic plate 12a and the lower ceramic plate 12b is are not particularly limited except for the configurations of the purge gas flow path, the vacuum suction path, and the thermocouple insertion path, respectively, and may have the same configuration as the ceramic plates employed in known ceramic susceptors or ceramic heaters. Therefore, the upper ceramic plate 12a and the lower ceramic plate 12b preferably contain aluminum nitride or aluminum oxide, more preferably contain aluminum nitride, from the viewpoints of excellent thermal conductivity, high electrical insulation, and thermal expansion characteristics close to those of silicon.

[0017] When viewed in plan, the ceramic plate assembly 12 has a central zone Z1 defined as a circular region in which the ceramic shaft 22 should be concentrically arranged, and an outer peripheral zone Z2 outside the central zone Z1. Therefore, the circular region corresponding to the central zone Z1 is specified as a region corresponding to the region surrounded by the outer peripheral circle of the ceramic shaft 22 when the ceramic shaft 22 is attached to the ceramic plate assembly 12.

[0018] The internal electrode 14 is an electrode embedded in the ceramic plate assembly 12 and includes at least one selected from the group consisting of a heater electrode, an RF electrode, and an ESC electrode. The heater electrode is not particularly limited, and for example, it may be a conductive coil wired in one stroke over the entire surface of the upper ceramic plate 12a. Terminal rods 24 are connected to both ends of the heater electrode for power supply, and the terminal rods 24 are connected to a heater power source (not shown) (optionally via a cable 26). When power is supplied from the heater power source, the heater electrode generates heat and heats the wafer placed on the surface of the first surface 12d. The heater electrode is not limited to a coil and may be, for example, a ribbon (elongated thin plate), a mesh, or printing. When a high frequency is applied to the RF electrode, film formation by a plasma CVD process is enabled. The ESC electrode is an abbreviation for an electrostatic chuck (ESC) electrode and is also referred to as an electrostatic electrode. The ESC electrode is preferably a circular thin-layer electrode having a slightly smaller diameter than the ceramic plate assembly 12 and may be, for example, a mesh-like electrode formed by knitting thin metal wires into a net shape and forming a sheet. The ESC electrode may be used as a plasma electrode. That is, by applying a high frequency to the ESC electrode, the ESC electrode can also be used as an RF electrode, and film formation by a plasma CVD process can also be performed. Terminal rods 24 are connected to the ESC electrode for power supply, and the terminal rods 24 are connected to an external power source (not shown) (optionally via a cable 26). When a voltage is applied by the external power source, the ESC electrode chucks the wafer placed on the surface of the ceramic plate assembly 12 by the Johnson-Rahbek force. Preferably, the internal electrode 14 preferably includes a heater electrode 14a and an RF or ESC electrode 14b. Also, although the internal electrode 14 is typically embedded in the upper ceramic plate 12a as shown in FIG. 3, the internal electrode 14 may also be embedded in the lower ceramic plate 12b.

[0019] Optionally, the ceramic shaft 22 may be concentrically attached to the central zone Z1 on the second surface 12e of the ceramic plate assembly 12. The ceramic shaft 22 is a cylindrical member having an internal space S, and may have the same configuration as the ceramic shaft employed in a known ceramic susceptor or ceramic heater. The internal space S is configured such that the terminal rod 24 and / or the cable 26 passes therethrough. The ceramic shaft 22 is preferably made of the same ceramic material as the ceramic plate assembly 12. Accordingly, the ceramic shaft 22 preferably contains aluminum nitride or aluminum oxide, more preferably contains aluminum nitride. The upper end surface of the ceramic shaft 22 is preferably joined to the second surface 12e of the ceramic plate assembly 12 by solid-phase bonding or diffusion bonding. The outer diameter of the ceramic shaft 22 is not particularly limited, and is, for example, about 40 mm. The inner diameter of the ceramic shaft 22 (the diameter of the internal space S) is also not particularly limited, and is, for example, about 36 mm.

[0020] The purge gas groove 16 is a groove that forms a purge gas flow path together with the bonding surface 12c, and is provided on the bonding surface 12c side of the upper ceramic plate 12a or the lower ceramic plate 12b. The presence of the purge gas groove 16 or the purge gas flow path allows an inert purge gas to be ejected to the outer peripheral portion of the ceramic plate assembly 12 (particularly the first surface 12d), preventing the process gas from flowing into the back surface of a wafer (not shown) placed on the first surface 12d. Accordingly, during the manufacturing process of the semiconductor device, it is possible to prevent the process gas from entering the back surface of the wafer placed on the first surface 12d and causing deposits. The purge gas groove 16 is preferably provided in the upper ceramic plate 12a as shown in FIG. 3, but may be provided in the lower ceramic plate 12b.

[0021] The purge gas groove 16 has a straight portion 16a linearly arranged from a purge gas inlet 16c in the central zone Z1 toward the outer peripheral zone Z2, and an extending portion 16b extending in the outer peripheral zone Z2 from the straight portion 16a. The extending portion 16b extends from the straight portion 16a in the outer peripheral zone Z2 and reaches a plurality of purge gas outlets 16d arranged at the outer peripheral portion of the ceramic plate assembly 12 through one or more selected from the group consisting of branching, refraction, bending, and straight advancement. That is, the straight portion 16a has a configuration suitable for avoiding the concentration of the purge gas groove 16, the vacuum suction groove 18, and the thermocouple insertion groove 20 in the central zone Z1 and its vicinity, while the extending portion 16b has a configuration suitable for reaching the plurality of purge gas outlets 16d arranged at the outer peripheral portion of the ceramic plate assembly 12 with an as-equivalent path length as possible. From such a viewpoint, it is preferable that the extending portion 16b includes all of branching, refraction, bending, and straight advancement. The number of components selected from the group consisting of branching, refraction, bending, and straight advancement in the extending portion 16b may be appropriately determined according to the number and arrangement of the purge gas outlets 16d, and is not particularly limited as long as it is 1 or more, but is preferably 2 or more, more preferably 3 or more, still more preferably 4 or more, particularly preferably 5 or more, for example 10 or more. The components selected from the group consisting of branching, refraction, bending, and straight advancement in the extending portion 16b may be appropriately combined so as to reach the plurality of purge gas outlets 16d with an as-equivalent path length as possible without intersecting the vacuum suction groove 18 and the thermocouple insertion groove 20. Specifically, each path length of the purge gas groove 16 from the purge gas inlet 16c to each of the plurality of purge gas outlets 16d is preferably within ±10% of the average path length of the purge gas groove 16, more preferably within ±8%. The path length of the purge gas groove 16 is the planar distance from the purge gas inlet 16c to the purge gas outlet 16d, and does not include the depth direction distance of the purge gas jet outlet that may be provided in communication with the purge gas outlet 16d or the depth direction distance of the purge gas jet outlet 30 that may be provided in communication with the purge gas inlet 16c. In order to evenly eject the purge gas over the outer peripheral portion of the ceramic plate assembly 12, the plurality of purge gas outlets 16d are preferably arranged at equal intervals along the outer peripheral portion of the ceramic plate assembly 12.The number of purge gas outlets 16d is not particularly limited, but is typically from 4 to 24, for example 16 as shown in FIGS. 1 and 2.

[0022] When the ceramic susceptor 10 includes a ceramic shaft 22, it is preferable to provide a purge gas supply hole 28 that penetrates the side wall and the lower ceramic plate 12b constituting the ceramic shaft 22 and communicates with the purge gas inlet 16c. By doing so, the purge gas supply hole 28, the purge gas inlet 16c, the purge gas groove 16, and the purge gas outlet 16d together constitute a purge gas flow path.

[0023] The purge gas outlet 16d is an open end located opposite to the purge gas inlet 16c of the purge gas groove 16, and has a role of enabling an inert purge gas to be ejected to the outer peripheral portion of the ceramic plate assembly 12. In this regard, in order to more effectively realize the function of preventing the process gas from entering the back surface of the wafer placed on the first surface 12d and generating deposits during the manufacturing process of the semiconductor device, it is preferable to adopt a configuration in which the purge gas can be ejected from the outer peripheral portion of the first surface 12d of the ceramic plate assembly 12. That is, it is preferable to provide a purge gas ejection port 30 for ejecting the purge gas from the outer peripheral portion of the first surface 12d. For example, as shown in FIG. 3, a purge ring 32 is annularly provided along the outer peripheral edge of the ceramic plate assembly 12, and is preferably configured to guide the purge gas discharged from the purge gas outlet 16d to be ejected from the outer peripheral portion of the first surface 12d. In this case, the gap between the outer peripheral edge of the ceramic plate assembly 12 and the purge ring 32 can constitute the purge gas ejection port 30. Alternatively, the upper ceramic plate 12a may further include a vertical hole (not shown) that communicates with the first surface 12d from the purge gas outlet 16d. In this case, this vertical hole can constitute the purge gas ejection port 30 that enables the purge gas to be ejected from the outer peripheral portion of the first surface 12d.

[0024] The vacuum suction groove 18 is a groove that forms a vacuum suction path together with the joint surface 12c, and is provided on the joint surface 12c side of the upper ceramic plate 12a or the lower ceramic plate 12b without intersecting with the purge gas groove 16. The presence of the vacuum suction groove 18 or the vacuum suction path enables a wafer (not shown) placed on the first surface 12d of the ceramic plate assembly 12 to be adsorbed and fixed to the first surface 12d by vacuum suction during the manufacturing process of the semiconductor device. That is, it is possible to prevent the wafer placed on the first surface 12d from moving during the manufacturing process of the semiconductor device. The vacuum suction groove 18 is preferably provided in the lower ceramic plate 12b as shown in FIG. 3, but may also be provided in the upper ceramic plate 12a.

[0025] The vacuum suction groove 18 has a straight portion 18a linearly arranged from the vacuum suction inlet 18c in the central zone Z1 toward the outer peripheral zone Z2, and an extending portion 18b extending in the outer peripheral zone Z2 from the straight portion 18a. The extending portion 18b extends from the straight portion 18a in the outer peripheral zone Z2 and reaches a plurality of vacuum suction outlets 18d of the ceramic plate assembly 12 through one or more selected from the group consisting of branching, refraction, bending, and straight advancement. That is, the straight portion 18a has a configuration suitable for avoiding the concentration of the purge gas groove 16, the vacuum suction groove 18, and the thermocouple insertion groove 20 in the central zone Z1 and its vicinity, while the extending portion 18b has a configuration suitable for reaching the plurality of vacuum suction outlets 18d arranged in the outer peripheral zone Z2 with an approximately equal path length. From this perspective, the extending portion 18b preferably includes all of branching, refraction, bending, and straight advancement. The number of components selected from the group consisting of branching, refraction, bending, and straight advancement in the extending portion 18b may be appropriately determined according to the number and arrangement of the vacuum suction outlets 18d, and is not particularly limited as long as it is 1 or more, but is preferably 2 or more, more preferably 3 or more, still more preferably 4 or more, particularly preferably 5 or more, for example 6 or more. The components selected from the group consisting of branching, refraction, bending, and straight advancement in the extending portion 18b do not intersect with the purge gas groove 16 and the thermocouple insertion groove 20, and a plurality of Vacuum suction outlet 18dThey may be appropriately combined so that they can reach with as uniform a path length as possible. Specifically, it is preferable that each path length of the vacuum suction grooves 18 from the vacuum suction inlet 18c to each of the plurality of vacuum suction outlets 18d is within ±10% of the average path length of the vacuum suction grooves 18, more preferably within ±8%. The path length of the vacuum suction grooves 18 is the planar distance from the vacuum suction inlet 18c to the vacuum suction outlet 18d, and does not include the distance in the depth direction of the vacuum suction outlet 18d and the distance in the depth direction of the vacuum suction holes 34 that may be provided in communication with the vacuum suction inlet 18c.

[0026] In order to adsorb and fix the wafer to the first surface 12d as uniformly as possible, the plurality of vacuum suction outlets 18d are preferably arranged rotationally symmetrically with respect to the central axis of the ceramic plate assembly 12. The number of the vacuum suction outlets 18d is not particularly limited as long as it is 2 or more, but is typically 2 to 6, and is 2 as shown in FIGS. 1 and 2, for example.

[0027] When the ceramic susceptor 10 includes a ceramic shaft 22, it is preferable that a vacuum suction hole 34 is provided that penetrates the side wall and the lower ceramic plate 12b constituting the ceramic shaft 22 and communicates with the vacuum suction inlet 18c. By doing so, the vacuum suction hole 34, the vacuum suction inlet 18c, the vacuum suction grooves 18, and the vacuum suction outlets 18d constitute a vacuum suction path as a whole. A vacuum pump (not shown) may be connected to the distal end of the vacuum suction hole 34.

[0028] The thermocouple insertion groove 20 is a groove that constitutes a thermocouple insertion path together with the joint surface 12c, and is provided on the joint surface 12c side of the upper ceramic plate 12a or the lower ceramic plate without intersecting the purge gas flow path and the vacuum suction By path. The presence of the thermocouple insertion groove 20 or the thermocouple insertion path allows the thermocouple 36 to be inserted or accommodated therein, and the temperature in the outer peripheral zone Z2 of the ceramic plate assembly 12 or the internal electrode 14 can be measured. The thermocouple insertion groove 20 is preferably provided in the lower ceramic plate 12b as shown in FIG. 3, but may be provided in the upper ceramic plate 12a.

[0029] The thermocouple insertion groove 20 has a straight portion 20a that is linearly arranged from the thermocouple insertion port 20b in the central zone Z1 toward the thermocouple insertion path end 20c located in the outer peripheral zone Z2. That is, the straight portion 20a is not only in a shape that facilitates the insertion of the thermocouple 36, but also can be said to be a configuration suitable for avoiding the concentration of the purge gas groove 16, the vacuum suction groove 18, and the thermocouple insertion groove 20 in the central zone Z1 and its vicinity. The thermocouple insertion path end 20c is preferably a closed end for accurate temperature measurement.

[0030] Inside the internal space S of the ceramic shaft 22, a tubular thermocouple guide 38 for guiding the insertion of the thermocouple 36 into the thermocouple insertion path is preferably provided on the second surface 12e of the ceramic plate assembly 12 in communication with the thermocouple insertion port 20b. According to this configuration, the thermocouple 36 can be smoothly inserted into the thermocouple insertion path. Therefore, the ceramic susceptor 10 preferably further includes the thermocouple 36 inserted into the thermocouple insertion path through the thermocouple guide 38 and the thermocouple insertion port 20b. A thermometer (not shown) can be connected to the distal end of the thermocouple 36.

[0031] Preferably, separately from the above-described thermocouple insertion groove 20 to the thermocouple insertion path, a thermocouple insertion hole 40 as a vertical hole penetrating the lower ceramic plate 12b from the second surface 12e to the upper ceramic plate 12a may be provided in the central zone Z1 of the ceramic plate assembly 12. By inserting another thermocouple 36 into this thermocouple insertion hole 40, the temperature in the central zone Z1 of the ceramic plate assembly 12 to the internal electrode 14 can be measured.

[0032] FigureAs shown in Fig. 6, when each of the purge gas groove 16, the vacuum suction groove 18, and the thermocouple insertion groove 20 is viewed in a cross-section perpendicular to the longitudinal direction of the groove, the various dimensions of the grooves 16, 18, 20 are as follows, which are preferable from the viewpoints of ensuring the gas flow rate, ensuring the vacuum suction force, and smoothly inserting the thermocouple. That is, the height A at the center of the grooves 16, 18, 20 is preferably 0.1 to 3.0 mm. The height B at the end of the grooves 16, 18, 20 is preferably 0.5 to 3.0 mm. The width C of the grooves 16, 18, 20 is preferably 2.0 to 10.0 mm. Further, as in the grooves 16, 18, 20 shown on the right side of Fig. 6, the height A at the center of the grooves 16, 18, 20 is preferably smaller than the height B at the end of the grooves 16, 18, 20. Specifically, the ratio (B / A) of the height B at the end of the grooves 16, 18, 20 to the height A at the center of the grooves 16, 18, 20 is preferably 0.2 to 1.0. Note that the above B / A ratio is a value calculated individually for each of the purge gas groove 16, the vacuum suction groove 18, and the thermocouple insertion groove 20, such as the B / A ratio of the purge gas groove 16, the B / A ratio of the vacuum suction groove 18, and the B / A ratio of the thermocouple insertion groove 20, and should not be calculated based on B and A for different types of grooves. The height A at the center may be a common value or different values among the purge gas groove 16, the vacuum suction groove 18, and the thermocouple insertion groove 20. Similarly, the height B at the end may be a common value or different values among the purge gas groove 16, the vacuum suction groove 18, and the thermocouple insertion groove 20, and the width C may also be a common value or different values.

[0033] The ceramic plate assembly 12 to the ceramic susceptor 10 can be manufactured using known techniques, except that the arrangement and specifications of the purge gas groove 16, the vacuum suction groove 18, and the thermocouple insertion groove 20 are as described above. For example, the ceramic plate assembly 12 includes a disk-shaped upper ceramic plate 12a in which the internal electrode 14 is embedded and at least one kind of groove for internal path (for example, the purge gas groove 16) is formed, and a disk-shaped lower ceramic plate 12b in which other grooves for internal path (for example, the vacuum suction groove 18 and the thermocouple insertion groove 20) are formed. After applying a known ceramic-based bonding agent to the surfaces to be joined (that is, the portions other than the grooves on the surfaces where the grooves are present) and bonding them together, it can be manufactured by appropriately firing.

Claims

1. A disc-shaped ceramic plate assembly including an upper ceramic plate and a lower ceramic plate joined together at a joining surface, having a first surface on the side opposite to the joining surface of the upper ceramic plate and a second surface on the side opposite to the joining surface of the lower ceramic plate, At least one internal electrode selected from the group consisting of a heater electrode, an RF electrode, and an ESC electrode, embedded in the ceramic plate assembly, A purge gas groove provided on the joining surface side of the upper ceramic plate or the lower ceramic plate, and constituting a purge gas flow path together with the joining surface, A vacuum suction groove provided on the joining surface side of the upper ceramic plate or the lower ceramic plate without intersecting the purge gas groove, and constituting a vacuum suction path together with the joining surface, A thermocouple insertion groove provided on the joining surface side of the upper ceramic plate or the lower ceramic plate without intersecting the purge gas flow path and the vacuum suction path, and constituting a thermocouple insertion path together with the joining surface, A ceramic susceptor comprising: The ceramic plate assembly has a central zone defined as a circular region in which ceramic shafts should be arranged concentrically in a plan view, and an outer peripheral zone outside the central zone, The purge gas groove has a straight portion linearly arranged from a purge gas inlet in the central zone toward the outer peripheral zone, and an extending portion extending from the straight portion in the outer peripheral zone and reaching a plurality of purge gas outlets arranged at the outer peripheral portion of the ceramic plate assembly through one or more selected from the group consisting of branching, refracting, curving, and straight advancing, The vacuum suction groove has a straight portion linearly arranged from a vacuum suction inlet in the central zone toward the outer peripheral zone, and an extending portion extending from the straight portion in the outer peripheral zone and reaching a plurality of vacuum suction outlets of the ceramic plate assembly through one or more selected from the group consisting of branching, refracting, curving, and straight advancing, The thermocouple insertion groove has a straight portion linearly arranged from a thermocouple insertion inlet in the central zone toward a thermocouple insertion path end located in the outer peripheral zone, The angle θ formed by the straight portion of the purge gas groove and the straight portion of the thermocouple insertion groove １ , and the angle θ formed by the straight portion of the purge gas groove and the straight portion of the vacuum suction groove ２ satisfy the following relationship: 50° < θ １ < 180°, 135° < θ ２ < 310°, and θ １ <θ ２ A ceramic susceptor satisfying the above.

2. The ceramic susceptor according to claim 1, further comprising a cylindrical ceramic shaft concentrically attached to the central zone on the second surface of the ceramic plate assembly.

3. The ceramic susceptor according to claim 1 or 2, wherein each path length of the purge gas grooves from the purge gas inlet to each of the plurality of purge gas outlets is within ±10% of the average path length of the purge gas grooves.

4. The ceramic susceptor according to claim 1 or 2, wherein each path length of the vacuum suction grooves from the vacuum suction inlet to each of the plurality of vacuum suction outlets is within ±10% of the average path length of the vacuum suction grooves.

5. The ceramic susceptor according to claim 2, comprising a purge gas supply hole penetrating through the side wall constituting the ceramic shaft and the lower ceramic plate and communicating with the purge gas inlet, whereby the purge gas supply hole, the purge gas inlet, the purge gas grooves, and the purge gas outlets together constitute the purge gas flow path.

6. The ceramic susceptor according to claim 1 or 2, wherein the plurality of purge gas outlets are arranged at equal intervals along the outer peripheral portion of the ceramic plate assembly.

7. The ceramic susceptor according to claim 1 or 2, further comprising a purge ring provided annularly along the outer peripheral edge of the ceramic plate assembly and guiding the purge gas discharged from the purge gas outlet to jet out from the outer peripheral portion of the first surface, and a gap between the outer peripheral edge of the ceramic plate assembly and the purge ring constitutes a purge gas jet outlet.

8. The ceramic susceptor according to claim 1 or 2, wherein the upper ceramic plate further comprises a vertical hole communicating with the first surface from the purge gas outlet, and the vertical hole constitutes a purge gas jet outlet enabling the jet of the purge gas from the outer peripheral portion of the first surface.

9. The ceramic susceptor according to claim 2, comprising a vacuum suction hole penetrating through the side wall constituting the ceramic shaft and the lower ceramic plate and communicating with the vacuum suction inlet, whereby the vacuum suction hole, the vacuum suction inlet, the vacuum suction grooves, and the vacuum suction outlets together constitute the vacuum suction path.

10. The ceramic susceptor according to claim 1 or 2, wherein the plurality of vacuum suction outlets are arranged rotationally symmetrically with respect to the central axis of the ceramic plate assembly.

11. In the internal space of the ceramic shaft, a tubular thermocouple guide is further provided on the second surface of the ceramic plate assembly in communication with the thermocouple insertion port for guiding the insertion of the thermocouple into the thermocouple insertion path. The ceramic susceptor according to claim 1 or 2.

12. The ceramic susceptor according to claim 11, further comprising a thermocouple inserted into the thermocouple insertion path through the thermocouple guide and the thermocouple insertion port.

13. When each of the purge gas groove, the vacuum suction groove, and the thermocouple insertion groove is viewed in a cross section perpendicular to the longitudinal direction of the groove, the height of the central portion of the groove is 0.1 to 3.0 mm, the height of the end portion of the groove is 0.5 to 3.0 mm, the width of the groove is 2.0 to 10.0 mm, and the ratio of the height of the end portion of the groove to the height of the central portion of the groove is 0.2 to 1.

0. The ceramic susceptor according to claim 1 or 2.

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