Wafer support device and SiC epitaxial growth device

Abstract

A wafer support device is provided that can smoothly position a wafer and can suppress damage to a wafer guide during regeneration. [Solution] The device has a support table and a wafer guide portion. The support table has a support surface that supports a wafer. The support table rotates around a central axis that extends in a normal direction to the support surface. The wafer guide portion has a first chamfered portion and a second chamfered portion. The wafer guide portion is annular in shape, surrounding the periphery of the wafer supported on the support surface with the central axis as its center. The first chamfered portion slopes downward as it moves from the upper surface of the wafer guide portion toward the inside in the radial direction centered on the central axis. The second chamfered portion has a first inclined region that slopes downward as it moves toward the inside in the radial direction at an inclination angle greater than the inclination angle of the first chamfered portion with respect to the support surface. The second chamfered portion is connected to the inside in the radial direction of the first chamfered portion.

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to a wafer support apparatus and a SiC epitaxial growth apparatus. [Background technology]

[0002] In the wafer support device of a SiC epitaxial growth system, wafer guides are placed around the wafer supported on the support surface to position and hold the wafer. The inner diameter of the wafer guide is designed to be several millimeters larger than the diameter of the wafer, taking into account the alignment accuracy of automatic wafer transport. In this case, the wafer will shift to one side during the SiC epitaxial growth process, reducing the uniformity of the film thickness and the in-plane carrier concentration distribution of the resulting SiC epitaxial film.

[0003] On the other hand, if the inner diameter of the wafer guide is made small, any misalignment during automatic wafer transport can cause the wafer to ride up onto the wafer guide, resulting in problems such as the wafer falling.

[0004] Furthermore, reaction products accumulate on the wafer guide during the SiC epitaxial growth process. To ensure smooth SiC epitaxial growth, the accumulated reaction products are removed by polishing or other processes to regenerate the wafer guide. However, removing the reaction products from the intersection between the top surface and the circumferential surface of the wafer guide, where the reaction products are likely to accumulate, can cause damage. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-102018 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a wafer support device and a SiC epitaxial growth device that can smoothly position a wafer and can suppress damage to a wafer guide during reconditioning. [Means for solving the problem]

[0007] A wafer support device according to an embodiment includes a support table and a wafer guide portion. The support table has a support surface that supports a wafer. The support table rotates about a central axis that extends in a normal direction to the support surface. The wafer guide portion has a first chamfered portion and a second chamfered portion. The wafer guide portion is annular and surrounds the periphery of the wafer supported on the support surface, with the central axis as its center. The first chamfered portion slopes downward as it moves radially inward from the upper surface of the wafer guide portion about the central axis. The second chamfered portion has a first inclined region that slopes downward as it moves radially inward at an inclination angle greater than the inclination angle of the first chamfered portion relative to the support surface. The second chamfered portion is connected to the radially inner side of the first chamfered portion. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing an SiC epitaxial growth apparatus according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the wafer supporting device of the first embodiment. [Figure 3] A partially enlarged view of Figure 2. [Figure 4] FIG. [Figure 5] FIG. 10 is a partially enlarged view showing the wafer support device when misalignment occurs. [Figure 6] FIG. 10 is a partially enlarged view showing the wafer support device when misalignment occurs. [Figure 7] FIG. 10 is a partial cross-sectional view showing the wafer support device after the SiC epitaxial growth process. [Figure 8] FIG. 10 is a partial cross-sectional view showing the wafer support device after the SiC epitaxial growth process. [Figure 9] FIG. 10 is a partially enlarged view showing a wafer support device according to a second embodiment. [Figure 10] FIG. 10 is a partially enlarged view showing a wafer support device according to a third embodiment. [Figure 11] FIG. 10 is a partially enlarged view showing a wafer support device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a wafer support device and a SiC epitaxial growth device according to an embodiment will be described with reference to the drawings. In the following description, components having the same or similar functions are designated by the same reference numerals. Duplicate descriptions of those components may be omitted.

[0010] The configuration of the SiC epitaxial growth apparatus will be described below. FIG. 1 is a cross-sectional view of a SiC epitaxial growth apparatus 1 having a wafer support device 10 according to an embodiment.

[0011] In the following description, the side into which the supplied source gas flows in will be referred to as the upper side, and the side from which it flows out will be referred to as the lower side. In the following description, the direction along the central axis J will be simply referred to as the "axial direction." Furthermore, the radial direction centered on the central axis J may be simply referred to as the "radial direction." In the "radial direction," the side approaching the central axis J will be referred to as the inner side, and the side away from the central axis J will be referred to as the outer side. Furthermore, the circumferential direction centered on the central axis J may be simply referred to as the "circumferential direction."

[0012] 1, a SiC epitaxial growth apparatus 1 grows an epitaxial film, which will become an active region, on a wafer W made of silicon carbide (SiC) by chemical vapor deposition (thermal CVD) or the like. The SiC epitaxial growth apparatus 1 includes a chamber 2, a reactor 3, an upper heater 4, a lower heater 5, a partition cylinder 7, and a wafer support device 10.

[0013] The chamber 2 is formed of a metal material such as stainless steel (SUS). The chamber 2 houses a reactor 3, an upper heater 4, a lower heater 5, a rotating cylinder 6, a partition cylinder 7, and a wafer support device 10. The chamber 2 has an inlet 2A, an exhaust port 2B, and an insertion port 2C. The inlet 2A is provided at the top of the chamber 2. The exhaust port 2B and the insertion port 2C are provided to penetrate a bottom wall 2D of the chamber 2 in the axial direction.

[0014] The inlet 2A is formed to open at the upper end of the chamber 2. The inlet 2A is a point where the working gas including the source gas G supplied from above along the central axis J is introduced into the chamber 2. The exhaust port 2B is a point where the working gas including the source gas G used in the SiC epitaxial growth process is exhausted.

[0015] The source gas G reacts on the wafer W to form an epitaxial film. The source gas G is, for example, a Si-based gas and a C-based gas. The Si-based gas is, for example, silane (SiH), dichlorosilane (SiH2Cl2), trichlorosilane (SiHCl3), or tetrachlorosilane (SiCl4). The C-based gas is, for example, propane (C3H8). The source gas G in this embodiment is, for example, SiH4+C3H8 (flow rate: tens to hundreds of sccm).

[0016] Gases used in addition to the source gas G include impurity gas, carrier gas, and other gases. Examples of impurity gases include N2 (N-type impurity) and TMA (P-type impurity). The flow rate of the impurity gas is preferably in the range of several [sccm] to several hundred [sccm]. Examples of carrier gases include H2 (during growth) and Ar (during transportation). The flow rate of the carrier gas is preferably in the range of 100 [slm] to 200 [slm]. Examples of other gases include HCl (for particle suppression during growth and high-speed growth). The flow rate of HCl gas is preferably in the range of several tens [sccm] to several [slm].

[0017] The reactor 3 constitutes a furnace. The reactor 3 is made of graphite, for example. The inner surface of the reactor 3 may be coated with SiC or TaC to prevent dust generation. The reactor 3 has a first cylindrical portion 3A, a tapered portion 3B, and a second cylindrical portion 3C.

[0018] The first cylindrical portion 3A is located at the upper side of the reactor 3. The first cylindrical portion 3A has a cylindrical shape centered on a central axis J. The first cylindrical portion 3A opens below the inlet 2A of the chamber 2. Gases including the source gas G introduced from the inlet 2A are introduced into the internal space of the reactor 3. The internal space of the reactor 3 is a film formation space K.

[0019] The tapered portion 3B extends radially outward from the lower end of the first cylindrical portion 3A downward. The second cylindrical portion 3C is cylindrical and centered on the central axis J. The second cylindrical portion 3C extends downward from the lower end of the tapered portion 3B. The radial position of the second cylindrical portion 3C is radially outward from the exhaust port 2B of the chamber 2. The tapered portion 3B is disposed in a range including the axial position of the first surface Wa of the wafer W facing upward in the vertical direction. In other words, the tapered portion 3B is disposed in a range including a position intersecting with an imaginary plane including the first surface Wa of the wafer W. Therefore, the gas containing the source gas G introduced into the film formation space K from the inlet 2A flows radially outward along the first surface Wa after reaching the wafer W. The gas containing the source gas G that flows radially outward from the wafer W is guided by the tapered portion 3B and the second cylindrical portion 3C and discharged from the exhaust port 2B of the chamber 2.

[0020] The upper heater 4 circumferentially surrounds the outer periphery of the first cylindrical portion 3A of the reactor 3. The upper heater 4 extends in the axial direction along the first cylindrical portion 3A. The lower heater 5 is disposed below the wafer support device 10 and spaced apart from the wafer support device 10. The lower heater 5 is, for example, annular and extends in the circumferential direction. The wafer W is heated by the upper heater 4 and the lower heater 5 to a temperature in the range of 1500 to 1650°C, for example. The upper heater 4 and the lower heater 5 may be publicly known heaters.

[0021] The partition cylinder 7 is fixed to the bottom wall 2D of the chamber 2. The partition cylinder 7 is cylindrical and has a central axis J as its center. The partition cylinder 7 extends upward along the axial direction. The partition cylinder 7 is disposed radially inward of the second cylindrical portion 3C and radially outward of the first rotating cylinder 6A.

[0022] The configuration of the wafer support device 10 will be described below. 2 is a cross-sectional view showing the wafer support device 10 of the embodiment, and FIG. 3 is an enlarged view of a portion of FIG. As shown in FIGS. 2 and 3, the wafer support device 10 includes a rotary cylinder 6, a support table 11, a wafer guide unit 12, and an elevator unit 15.

[0023] The rotating shell 6 is rotatable in the circumferential direction. The rotating shell 6 has a cylindrical first rotating shell 6A centered on a central axis J, and a cylindrical second rotating shell 6B centered on the central axis J. The first rotating shell 6A is provided above the second rotating shell 6B. The first rotating shell 6A is disposed above the bottom wall 2D of the chamber 2. A lower heater 5 is disposed inside the first rotating shell 6A. The diameter of the first rotating shell 6A is larger than the diameter of the second rotating shell 6B. The second rotating shell 6B extends downward from the first rotating shell 6A. The second rotating shell 6B is inserted into the insertion opening 2C.

[0024] The support base 11 is disk-shaped and centered on the central axis J. The support base 11 is fixed to the first rotating barrel 6A of the rotating barrel 6. The support base 11 rotates in the circumferential direction with the rotation of the rotating barrel 6. The support base 11 is a susceptor. The support base 11 has a support surface 11A and a through hole 11B. The support surface 11A supports the wafer W from below, radially outward of the through hole 11B. The through hole 11B passes through the support base 11 in the axial direction, centered on the central axis J.

[0025] The support base 11 is made of graphite, for example, and may be coated with SiC or TaC to prevent dust generation.

[0026] [First embodiment of wafer guide portion 12] The wafer guide portion 12 is disposed by being joined from above to the peripheral edge portion of the support base 11. Although not shown in the drawings, a convex portion that protrudes from one side of the support base 11 and the wafer guide portion 12 toward the other is provided at the joint between the support base 11 and the wafer guide portion 12. A concave portion into which the convex portion fits is provided on the other side of the support base 11 and the wafer guide portion 12. By fitting the convex portion into the concave portion at the joint, the wafer guide portion 12 is fixed radially to the support base 11.

[0027] The wafer guide portion 12 has an annular shape that surrounds the wafer W supported on the support surface 11A, with the center being a central axis J extending in the normal direction of the support surface 11A. As an example, at least the surface of the wafer guide portion 12 is formed of poly-SiC. The wafer guide portion 12 may be configured to be entirely formed of poly-SiC, or may be configured to be formed of graphite with a SiC coating on the surface. Alternatively, the wafer guide portion 12 may be entirely or partially formed of sintered SiC or single crystal SiC.

[0028] However, when the wafer W rotates via the support base 11 during the epitaxial growth process, centrifugal force may cause the wafer W to move and collide with the wafer guide portion 12, potentially peeling off the SiC coating. In addition, the wafer guide portion 12 is unsuitable for regeneration by polishing, as described below. Therefore, it is preferable that the entire wafer guide portion 12 be made of poly-SiC.

[0029] 3, the wafer guide portion 12 has a generally rectangular outline shape in a cross section including the central axis J, surrounded by an upper surface 12a, an outer peripheral surface 12c, a lower surface 12d, a first chamfered portion 13, a second chamfered portion 20, and an outer chamfered portion 14. The outer peripheral surface 12c is a surface facing radially outward on the outer peripheral side wall of the wafer guide portion 12. For example, the outer peripheral surface 12c is flush with the outer peripheral surface of the support base 11, but it does not have to be flush.

[0030] In the following, the upper surface 12a, the outer peripheral surface 12c, the lower surface 12d, the first chamfered portion 13, the second chamfered portion 20, and the outer chamfered portion 14 will be described in terms of a cross section including the central axis J unless otherwise specified.

[0031] The first chamfered portion 13 is inclined downward as it moves radially inward from the upper surface 12a. The first chamfered portion 13 has a first inclined surface 13a that is linearly inclined downward as it moves radially inward. The first inclined surface 13a is inclined at an inclination angle θ1 with respect to the support surface 11A.

[0032] The outer chamfer 14 slopes downward as it extends radially outward from the upper surface 12a. The outer chamfer 14 has an inclined surface 14a that slopes linearly downward as it extends radially outward. The inclined surface 14a is inclined at an inclination angle θ1 with respect to the support surface 11A, similar to the first inclined surface 13a. The inclined surface 14a may be inclined at an inclination angle different from that of the first inclined surface 13a.

[0033] The second chamfered portion 20 has a first inclined region 21. The first inclined region 21 is inclined downward as it extends radially inward. The upper end of the first inclined region 21 is connected to the radially inner side of the first inclined surface 13a. The upper end of the first inclined region 21 is located above the first surface Wa of the wafer W. The lower end of the first inclined region 21 is circular, centered on the central axis J, and has a diameter larger than the diameter of the wafer W.

[0034] If the position of the upper end of the first inclined region 21 is the same as or lower than the position of the first surface Wa, the wafer W may be warped due to high temperatures, causing the edge of the wafer W to lift up. In this case, when the wafer W rotates via the support table 11 during the epitaxial growth process, the wafer W may move due to centrifugal force and jump out beyond the wafer guide portion 12. Therefore, by positioning the upper end of the first inclined region 21 above the position of the first surface Wa, it is possible to prevent the wafer W from jumping out of the wafer guide portion 12.

[0035] The first inclined region 21 has a curved surface 22 that slopes downward in a curved manner as it moves radially inward. The curved surface 22 is arc-shaped. The first inclined region 21 is inclined at an inclination angle θ2 with respect to the support surface 11A. The radially inner end of the first inclined region 21 intersects with the lower surface 12d of the wafer guide portion 12. The inclination angle θ2 of the first inclined region 21 is defined as the intersection angle of a tangent line that contacts the curved surface 22 with the support surface 11A. Therefore, the inclination angle θ2 increases as it moves radially inward. The inclination angle θ2 is greater than the inclination angle θ1 of the first inclined surface 13a of the first chamfered portion 13.

[0036] The lifting / lowering unit 15 can move up and down in the axial direction. The lifting / lowering unit 15 is axially shaped and extends in the axial direction around the central axis J. The lifting / lowering unit 15 has a cylindrical holding portion 15A at its upper end. The holding portion 15A may be the same part as the lifting / lowering unit 15, or may be a separate part connected to the lifting / lowering unit 15. The diameter of the holding portion 15A is smaller than the diameter of the through hole 11B in the support base 11.

[0037] The lifting unit 15 can move up and down in the axial direction between a lowered position shown in Fig. 2 and an elevated position shown in Fig. 4. When the lifting unit 15 is in the lowered position, it is disposed below the support base 11. That is, the lowered position of the lifting unit 15 is a position where the holder 15A is below the support base 11, and is a position where the holder 15A waits below the support base 11 after placing the wafer W on the support base 11. The holder 15A is separated from the wafer W when the lifting unit 15 is in the lowered position, but may be in contact with the wafer W when the wafer W is not rotating.

[0038] The raised position of the lifting unit 15 is a position where the holding unit 15A is above the wafer guide unit 12. The raised position is a position where the wafer W removed from the support table 11 after the SiC epitaxial growth process is handed over to a transfer arm or the like. The raised position is also a position where the wafer W before the SiC epitaxial growth process is handed over from a transfer arm or the like.

[0039] In the SiC epitaxial growth apparatus 1 configured as described above, when the wafer W after the SiC epitaxial growth process is removed from the wafer support device 10, the lifting unit 15 rises from the lowered standby position, and the holder 15A holds the underside of the wafer W while moving it to the raised position. The wafer W held by the holder 15A at the raised position is transferred to a transfer arm or the like. In the SiC epitaxial growth apparatus 1, the wafer W before the SiC epitaxial growth process is transferred from a transfer arm or the like to the holder 15A in the raised position. After the wafer W is transferred to the holder 15A, the lifting unit 15 lowers and places the wafer W on the support table 11 as shown in FIG. 2, and then moves to the lowered standby position and waits.

[0040] On the other hand, if misalignment occurs when the wafer W is supported by the holder 15A of the lifting unit 15, for example, the edge of the wafer W may run onto the first inclined region 21 of the second chamfered portion 20, as shown in Fig. 5. The wafer W that has run onto the first inclined region 21 slides down the curved surface 22, as shown by the hollow arrow in Fig. 5. As a result, the wafer W does not remain on the wafer guide portion 12, and is transferred to the support surface 11A of the support table 11, as shown in Fig. 6.

[0041] In the SiC epitaxial growth apparatus 1 in which the wafer W is transferred onto the support surface 11A, a gas containing the raw material gas G introduced into the film formation space K of the reactor 3 and heated to a high temperature (e.g., 1500 to 1650°C) by the upper heater 4 and the lower heater 5 flows radially outward from the center of the wafer W along the first surface Wa, as shown by the dashed line in Figure 2.

[0042] 7 is a partial cross-sectional view showing the wafer support device 10 after the SiC epitaxial growth process. By maintaining the supply of gas containing source gas G for a certain period of time while rotating the wafer W via the support table 11, an SiC epitaxial film Wb is formed on the first surface Wa of the wafer W, as shown in FIG. 7. In addition, a deposit DP, which is a reaction product, accumulates on the wafer guide portion 12.

[0043] During the process of supplying film-forming raw material to form a film on the wafer W, the raw material that reaches the wafer guide portion 12 moves and aggregates due to the migration effect, resulting in the accumulation of deposits DP. If an inflection point exists in the wafer guide portion 12, the movement slows down and the material is trapped, resulting in a thick deposit. Therefore, in the wafer guide portion 12 having the first chamfered portion 13, the second chamfered portion 20, and the outer chamfered portion 14, the deposits DP at the intersection of the top surface 12a and the first inclined surface 13a, which is the inflection point, the deposits DP at the intersection of the top surface 12a and the inclined surface 14a, and the deposits DP at the intersection of the first inclined surface 13a and the first inclined region 21 grow and accumulate to the greatest thickness.

[0044] FIG. 8 is a partial cross-sectional view showing the wafer support device 10 after the SiC epitaxial growth process when a wafer guide portion 12N that does not include the first chamfered portion 13, the second chamfered portion 20, and the outer chamfered portion 14 is used.

[0045] As shown in Figure 8, in the wafer guide portion 12N that does not have the first chamfered portion 13, the second chamfered portion 20, and the outer chamfered portion 14, the deposits DP grow and accumulate to the greatest thickness at the inflection points where the top surface 12a intersects with the inner peripheral surface 12b and where the top surface 12a intersects with the outer peripheral surface 12c. The deposits DP in the wafer guide portion 12N protrude toward the central axis J from the inner peripheral surface 12b and protrude radially outward from the outer peripheral surface 12c. Even if a slight chamfering amount of about 0.1 to 0.2 mm is applied, this is insufficient, and the deposits DP protrude radially.

[0046] In this case, when the wafer W is raised by the lifting unit 15 to remove it from the wafer support device 10, the deposits DP protruding toward the central axis J may come into contact with the edge of the wafer W. Furthermore, the deposits DP protruding radially outward beyond the outer circumferential surface 12c may come into contact with other components of the partition cylinder 7 and scatter or generate dust, potentially causing particles. Because the wafer guide unit 12N is expensive, if the accumulation of the deposits DP becomes large, the wafer guide unit 12 is regenerated by removing the deposits DP by, for example, polishing or grinding the inner circumferential surface 12b and the outer circumferential surface 12c.

[0047] At this time, since the intersection of the upper surface 12a and the inner peripheral surface 12b, which are the inflection points, and the intersection of the upper surface 12a and the outer peripheral surface 12c are both right angles and have an edge shape, there is a possibility that defects such as cracks may occur in the wafer guide portion 12N.

[0048] In contrast, in the wafer guide portion 12 of the wafer support device 10 of the embodiment, the first chamfered portion 13, the second chamfered portion 20, and the outer chamfered portion 14 are provided, so that the intersection angle between the upper surface 12a and the first inclined surface 13a, the intersection angle between the upper surface 12a and the inclined surface 14a, the intersection angle between the inclined surface 14a and the outer peripheral surface 12c, and the intersection angle between the first inclined surface 13a and the first inclined region 21 are all obtuse angles. Therefore, compared to the wafer guide portion 12N, which has a right-angle intersection that serves as an inflection point and is prone to stress concentration, the obtuse angle of the intersection that serves as an inflection point in the wafer guide portion 12 alleviates stress concentration, thereby suppressing the occurrence of cracks in the wafer guide portion 12. The wafer guide portion 12 of the wafer support device 10 of the embodiment can be regenerated while suppressing the occurrence of cracks in both the first inclined region 21 and the outer peripheral surface 12c.

[0049] The inclination angle θ2 of the first inclined region 21 is larger than the inclination angle θ1 of the first inclined surface 13a of the first chamfered portion 13, so the wafer W that has climbed up on the first inclined region 21 can be smoothly guided onto the support surface 11A. That is, the first inclined region 21 has a larger radially inward component of the normal force on the wafer W than the first inclined surface 13a, so the wafer W that has climbed up can be more smoothly guided onto the support surface 11A.

[0050] The inclination angle θ2 of the first inclined region 21 is preferably equal to or greater than 45 degrees. If the inclination angle θ2 is less than 45 degrees, the radially inward component of the normal force acting on the mounted wafer W may be insufficient, making it impossible to smoothly guide the wafer W onto the support surface 11A.

[0051] The inclination angle θ1 of the first inclined surface 13a is preferably equal to or greater than 10 degrees and less than 45 degrees. If the inclination angle θ1 is less than 10 degrees, the intersection angle between the first inclined region 21 and the first inclined surface 13a approaches a right-angle edge shape, which may cause cracks in the wafer guide portion 12 during reclaiming processing of the first inclined region 21. In addition, the deposit DP may easily protrude toward the central axis J beyond the first inclined region 21, which may cause the edge of the wafer W to come into contact with the deposit DP during transport, resulting in transport failure.

[0052] If the inclination angle θ1 is 45 degrees or more, the first inclined surface 13a may act as a barrier, hindering the flow of the source gas G radially outward along the first surface Wa of the wafer W and potentially generating turbulence. In this case, as described above, the uniformity of the in-plane distribution of the film thickness of the SiC epitaxial film Wb may be reduced. Therefore, by setting the inclination angle θ1 to be greater than or equal to 10 degrees and less than 45 degrees, it is possible to suppress cracking of the wafer guide portion 12 during reclaiming processing, problems with transport of the wafer W, generation of particles, and deterioration in the uniformity of the in-plane distribution of the film thickness of the SiC epitaxial film Wb.

[0053] Similarly, the inclination angle of the inclined surface 14a of the outer chamfered portion 14 relative to the support surface 11A is preferably 10 degrees or more and less than 45 degrees. If the inclination angle of the inclined surface 14a is less than 10 degrees, the intersection angle between the outer peripheral surface 12c and the inclined surface 14a approaches a right-angle edge shape, which may cause cracks in the wafer guide portion 12 during reclaiming of the outer peripheral surface 12c. Furthermore, deposits DP tend to protrude radially outward from the outer peripheral surface 12c, which may come into contact with other components of the partition tube 7 and cause scattering and dust generation, resulting in particles. If the inclination angle of the inclined surface 14a is 45 degrees or more, the source gas G flows radially outward from the upper surface 12a, creating a relatively negative pressure in the region between the extension of the upper surface 12a and the inclined surface 14a, making deposits DP more likely to occur.

[0054] According to at least one of the embodiments described above, the wafer guide portion 12 has the second chamfered portion 20, which is connected to the radially inner side of the first chamfered portion 13 and has the first inclined region 21 that slopes downward at an inclination angle θ2 that is larger than the inclination angle θ1 of the first chamfered portion 13 as it moves radially inward. This allows the wafer W to be smoothly positioned on the support surface 11A and prevents damage to the wafer guide portion 12 during reconditioning.

[0055] Furthermore, according to at least one embodiment, the radially inner end of the second chamfered portion 20 intersects with the lower surface 12d of the wafer guide portion 12, so that the inclination angle θ2 increases continuously from the upper end to the lower end of the second chamfered portion 20, thereby enabling the wafer W to be positioned on the support surface 11A more smoothly.

[0056] Furthermore, according to at least one embodiment, by setting the inclination angle θ1 to less than 45 degrees and the inclination angle θ2 to 45 degrees or more, it is possible to suppress cracking of the wafer guide portion 12 during reclamation processing, transport problems of the wafer W, generation of particles, and deterioration of the in-plane distribution uniformity of the film thickness of the SiC epitaxial film Wb. Also, it is possible to more smoothly guide the mounted wafer W onto the support surface 11A.

[0057] Furthermore, according to at least one embodiment, by positioning the connection portion between the first inclined surface 13a and the first inclined region 21 above the position of the first surface Wa, it is possible to prevent the wafer W from protruding from the wafer guide portion 12.

[0058] [Second embodiment of wafer guide portion 12] Next, a second embodiment of the wafer guide portion 12 will be described with reference to FIG. In this figure, the same elements as those in the first embodiment shown in FIGS. 1 to 8 are denoted by the same reference numerals, and the description thereof will be omitted.

[0059] FIG. 9 is a partially enlarged view showing the wafer support device 10 of the second embodiment. 9, the wafer guide portion 12 has an inner peripheral surface 12b that extends upward from the lower surface 12d along the central axis J. The radially inner end of the first inclined region 21 in the second chamfered portion 20 intersects with the inner peripheral surface 12b. The other configurations are the same as those of the first embodiment.

[0060] According to at least one embodiment, in addition to obtaining the same functions and effects as the first embodiment, the inner peripheral surface 12b extends upward, which further prevents the wafer W from jumping out of the wafer guide portion 12.

[0061] [Third embodiment of wafer guide portion 12] Next, a third embodiment of the wafer guide portion 12 will be described with reference to FIG. In this figure, the same elements as those in the first embodiment shown in FIGS. 1 to 8 are denoted by the same reference numerals, and the description thereof will be omitted.

[0062] FIG. 10 is a partially enlarged view showing the wafer support device 10 of the third embodiment. 10, the second chamfered portion 20 in the wafer guide portion 12 has a second inclined region 24. The second inclined region 24 is curved and tangent to the first inclined region 21 and the first chamfered portion 13. The second inclined region 24 is an arc-shaped r-chamfer. The other configurations are the same as those of the first embodiment.

[0063] According to at least one embodiment, the second inclined region 24 has an arc shape that contacts the first inclined region 21 and the first chamfered portion 13, respectively, so that no protrusions are formed at the intersections between the second inclined region 24 and the first inclined region 21 and the intersections between the second inclined region 24 and the first chamfered portion 13. Therefore, according to at least one embodiment, in addition to obtaining the same functions and effects as the first embodiment, it is possible to prevent deposits from growing thick and accumulating in the first inclined region 21 and the first chamfered portion 13.

[0064] [Fourth embodiment of wafer guide portion 12] Next, a fourth embodiment of the wafer guide portion 12 will be described with reference to FIG. In this figure, the same elements as those in the first embodiment shown in FIGS. 1 to 8 are denoted by the same reference numerals, and the description thereof will be omitted.

[0065] FIG. 11 is a partially enlarged view showing the wafer support device 10 of the fourth embodiment. As shown in FIG. 11, the first inclined region 21 in the wafer guide portion 12 has a second inclined surface 22a that slopes linearly downward as it moves radially inward. The other configurations are the same as those of the first embodiment.

[0066] According to at least one embodiment, the same functions and effects as those of the first embodiment can be obtained.

[0067] The first chamfered portion 13 may be an r-chamfer that curves and slopes in an arc downward from the upper surface 12a toward the inside in the radial direction, and the outer chamfered portion 14 may be an r-chamfer that curves and slopes in an arc downward from the upper surface 12a toward the outside in the radial direction.

[0068] The present embodiment includes the following additional aspects. (Appendix 1) a support table having a support surface for supporting a wafer and rotating about a central axis extending in a normal direction of the support surface; a wafer guide portion having an annular shape that surrounds the periphery of the wafer supported on the support surface, with the central axis as the center; Equipped with the wafer guide portion has a first chamfered portion that slopes downward from the top surface toward the inside in the radial direction centered on the central axis; a second chamfered portion having a first inclined region that slopes downward at an inclination angle greater than an inclination angle of the first chamfered portion with respect to the support surface as it slopes inward in the radial direction, the second chamfered portion being connected to the inner side of the first chamfered portion in the radial direction; A wafer support device comprising: (Appendix 2) the second chamfered portion has a curved second inclined region that is tangent to the first inclined region and the first chamfered portion in a cross section including the central axis, 2. The wafer support apparatus of claim 1. (Appendix 3) the second chamfered portion has an inner end in the radial direction that intersects with the lower surface of the wafer guide portion; 3. The wafer support device of claim 1 or 2. (Appendix 4) the wafer guide portion has an inner peripheral surface extending upward from a lower surface along the central axis, The second chamfered portion has an inner end in the radial direction that intersects with the inner circumferential surface. 4. The wafer support device according to any one of claims 1 to 3. (Appendix 5) an inclination angle of the first chamfered portion relative to the support surface is less than 45 degrees; The inclination angle of the first inclined region relative to the support surface is 45 degrees or more. 5. The wafer support device according to any one of claims 1 to 4. (Appendix 6) The first chamfered portion has a first inclined surface that is linearly inclined in a direction toward the lower side as it extends radially inward in a cross section including the central axis. 6. The wafer support device according to any one of claims 1 to 5. (Appendix 7) The first inclined region has a second inclined surface that is linearly inclined in a direction toward the lower side as it goes radially inward in a cross section including the central axis. 7. The wafer support device according to any one of claims 1 to 6. (Appendix 8) The first inclined region has a curved surface that curves downward as it extends radially inward in a cross section including the central axis. 7. The wafer support device according to any one of claims 1 to 6. (Appendix 9) At least the surface of the wafer guide portion is made of poly-SiC. 9. The wafer support device of any one of claims 1 to 8. (Appendix 10) 10. A SiC epitaxial growth apparatus comprising the wafer support device according to any one of claims 1 to 9.

[0069] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0070] 1...SiC epitaxial growth apparatus, 10...wafer support device, 11...support table, 11A...support surface, 12...wafer guide portion, 12a...upper surface, 12b...inner peripheral surface, 12c...outer peripheral surface, 13...first chamfered portion, 13a...first inclined surface, 20...second chamfered portion, 21...first inclined region, 22...curved surface, 24...second inclined region, J...central axis, W...wafer, Wa...first surface

Claims

1. a support table having a support surface for supporting a wafer and rotating about a central axis extending in a normal direction of the support surface; a wafer guide portion having an annular shape that surrounds the periphery of the wafer supported on the support surface, with the central axis as the center; Equipped with the wafer guide portion has a first chamfered portion that slopes downward from the top surface toward the inside in the radial direction centered on the central axis; a second chamfered portion having a first inclined region that inclines downward at an inclination angle greater than an inclination angle of the first chamfered portion with respect to the support surface as it extends inward in the radial direction, the second chamfered portion being connected to the inner side of the first chamfered portion in the radial direction; A wafer support device comprising:

2. the second chamfered portion has a curved second inclined region that is tangent to the first inclined region and the first chamfered portion in a cross section including the central axis, The wafer support device of claim 1 .

3. the second chamfered portion has an inner end in the radial direction that intersects with a lower surface of the wafer guide portion; The wafer support device of claim 1 .

4. the wafer guide portion has an inner peripheral surface extending upward from a lower surface along the central axis, The second chamfered portion has an inner end in the radial direction that intersects with the inner circumferential surface. The wafer support device of claim 1 .

5. an inclination angle of the first chamfered portion relative to the support surface is less than 45 degrees; The inclination angle of the first inclined region relative to the support surface is 45 degrees or more. The wafer support device of claim 1 .

6. the first chamfered portion has a first inclined surface that is linearly inclined downward as it extends radially inward in a cross section including the central axis, The wafer support device of claim 1 .

7. the first inclined region has a second inclined surface that is linearly inclined downward as it extends radially inward in a cross section including the central axis, The wafer support device of claim 1 .

8. the first inclined region has a curved surface that is inclined in a curved manner in a direction toward the inside in the radial direction and toward the lower side in a cross section including the central axis, The wafer support device of claim 1 .

9. At least the surface of the wafer guide portion is made of poly-SiC. The wafer support device of claim 1 .

10. A SiC epitaxial growth apparatus comprising the wafer support device according to any one of claims 1 to 9.

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