Wafer support device and sic epitaxial growth device

Abstract

Provided is a wafer support device capable of suppressing damage during recovery of a wafer guide. The present invention has a support base, a wafer guide portion, a first chamfered portion, and a second chamfered portion. The support base has a support surface for supporting a wafer. The wafer guide portion has an annular shape surrounding the periphery of the wafer supported on the support surface around a central axis extending in the normal direction of the support surface. The first chamfered portion connects an inner peripheral surface and an upper surface of the wafer guide portion, and extends upward from the inner peripheral surface toward an outer peripheral side. The second chamfered portion connects an outer peripheral surface and the upper surface of the wafer guide portion, and extends upward from the outer peripheral surface toward an inner peripheral side.

Description

Wafer support device and SiC epitaxial growth device

[0001] The present invention relates to a wafer support device and a SiC epitaxial growth apparatus. This application claims priority to Japanese Patent Application No. 2023-116980, filed on July 18, 2023, the contents of which are incorporated herein by reference.

[0002] In a wafer support device in a SiC epitaxial growth apparatus, a wafer guide is disposed around the wafer supported on a support surface. 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. Removal processing at the intersection between the top surface and the peripheral surface of the wafer guide, where reaction products are likely to accumulate, could result in damage.

[0003] JP 2022-102018 A

[0004] An object of the present invention is to provide a wafer support device and a SiC epitaxial growth device that can suppress damage to wafer guides during refurbishment.

[0005] The wafer support device of the embodiment has a support table, a wafer guide portion, a first chamfered portion, and a second chamfered portion. The support table has a support surface that supports a wafer. The wafer guide portion is annular and surrounds the periphery of the wafer supported on the support surface, with a central axis extending normal to the support surface as its center. The first chamfered portion connects the inner peripheral surface and the top surface of the wafer guide portion, and extends upward from the inner peripheral surface toward the outer peripheral side. The second chamfered portion connects the outer peripheral surface and the top surface of the wafer guide portion, and extends upward from the outer peripheral surface toward the inner peripheral side.

[0006] 1 is a cross-sectional view showing a SiC epitaxial growth apparatus according to an embodiment; FIG. 2 is a cross-sectional view showing a wafer support device according to an embodiment; FIG. 3 is a partial enlarged view of FIG. 2; FIG. 4 is a partial cross-sectional view showing a wafer support device after a SiC epitaxial growth process; FIG. 5 is a partial cross-sectional view showing a wafer support device after a SiC epitaxial growth process; FIG. 6 is a diagram showing an in-plane distribution of a SiC epitaxial film;

[0007] 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.

[0008] 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.

[0009] In the following description, the side into which the supplied source gas flows is referred to as the upper side, and the side from which it flows out is referred to as the lower side. In the following description, the direction along the central axis J is 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." Furthermore, the circumferential direction centered on the central axis J may be simply referred to as the "circumferential direction."

[0010] 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 member 3, an upper heater 4, a lower heater 5, a rotating cylinder 6, a partition cylinder 7, and a wafer support device 10.

[0011] The chamber 2 is formed of a metal material such as stainless steel (SUS). The chamber 2 accommodates a reactor member 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, the exhaust port 2B, and the insertion port 2C are provided so as to penetrate a bottom wall 2D of the chamber 2 in the axial direction.

[0012] The inlet 2A is formed to open at the upper end of the chamber 2. The inlet 2A is a location 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 location where the working gas including the source gas G used in the SiC epitaxial growth process is exhausted.

[0013] 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 ４ ), dichlorosilane (SiH ２ Cl ２ ), trichlorosilane (SiHCl ３ ), tetrachlorosilane (SiCl ４ ) The C-based gas is, for example, propane (C ３ H ８ ) In the embodiment, the source gas G is, for example, SiH ４ +C ３ H ８ (Flow rate: several tens to several hundreds sccm).

[0014] Gases used in addition to the source gas G include impurity gas, carrier gas, and other gases. An example of the impurity gas is N ２ (N-type impurity), TMA (P-type impurity), (flow rate: several to several hundred sccm). As a carrier gas, for example, H ２ (during growth), Ar (during transport), (flow rate: 100 to 200 slm). Other gases include HCl (for particle suppression during growth, high-speed growth), (flow rate: tens of sccm to hundreds of slm).

[0015] The reactor member 3 constitutes a furnace. The reactor member 3 is made of graphite, for example. The reactor member 3 may have an inner surface coated with SiC or TaC to prevent dust generation. The reactor member 3 has a first cylindrical portion 3A, a tapered portion 3B, and a second cylindrical portion 3C.

[0016] The first cylindrical portion 3A is located at the upper side of the reactor member 3. The first cylindrical portion 3A opens below the inlet 2A of the chamber 2. The gas containing the source gas G introduced from the inlet 2A is introduced into the internal space of the reactor member 3. The internal space of the reactor member 3 is a film formation space K.

[0017] The tapered portion 3B extends radially outward as it moves downward from the lower end of the first cylindrical portion 3A. 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 that includes the axial position of the first surface Wa of the wafer W facing upward in the vertical direction. 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 has flowed radially outward from the wafer W is guided by the tapered portion 3B and the second cylindrical portion 3C and is discharged from the exhaust port 2B of the chamber 2.

[0018] The upper heater 4 circumferentially surrounds the outer periphery of the first cylindrical portion 3A of the reactor member 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. Known heaters can be used for the upper heater 4 and the lower heater 5.

[0019] The rotating shell 6 is rotatable in the circumferential direction. The rotating shell 6 has a first rotating shell 6A and a second rotating shell 6B. 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.

[0020] The partition cylinder 7 is fixed to the bottom wall 2D of the chamber 2. 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 spaced apart radially outward from the first rotating cylinder 6A.

[0021] The configuration of the wafer support device 10 will be described below. Fig. 2 is a cross-sectional view showing the wafer support device 10 of the embodiment. Fig. 3 is an enlarged view of a portion of Fig. 2. As shown in Figs. 2 and 3, the wafer support device 10 includes a support table 11, a wafer guide portion 12, a first chamfering portion 13, a second chamfering portion 14, and a lifting portion 15.

[0022] The support base 11 has a disk shape 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.

[0023] The support base 11 is made of graphite, for example, and may be coated with SiC or TaC to prevent dust generation.

[0024] 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 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 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.

[0025] The wafer guide portion 12 has an annular shape that surrounds the wafer W supported on the support surface 11A, with a central axis J extending in the normal direction of the support surface 11A as its center. In a cross section including the central axis J, the wafer guide portion 12 has a rectangular cross section in which an intersection between the top surface 12a and the inner peripheral surface 12b is cut out by a first chamfered portion 13. In a cross section including the central axis J, the wafer guide portion 12 has a rectangular cross section in which an intersection between the top surface 12a and the outer peripheral surface 12c is cut out by a second chamfered portion 14.

[0026] That is, the first chamfered portion 13 connects the inner peripheral surface 12b and the upper surface 12a of the wafer guide portion 12, and extends upward from the inner peripheral surface 12b toward the outer peripheral side. In a cross section including the central axis J, the first chamfered portion 13 has a first inclined surface 13a that inclines upward from the inner peripheral surface 12b toward the outer peripheral side.

[0027] The second chamfered portion 14 connects the outer peripheral surface 12c and the upper surface 12a of the wafer guide portion 12 and extends upward from the outer peripheral surface 12c toward the inner peripheral side. The second chamfered portion 14 has a second inclined surface 14a that slopes upward from the outer peripheral surface 12c toward the inner peripheral side in a cross section including the central axis J. In other words, the first chamfered portion 13 and the second chamfered portion 14 are chamfers that extend linearly at an angle θ with respect to the upper surface 12a.

[0028] The first chamfered portion 13 may be an r-chamfer that curves in an arc shape from the inner circumferential surface 12 b toward the outer circumferential surface and extends upward, while the second chamfered portion 14 may be an r-chamfer that curves in an arc shape from the outer circumferential surface 12 c toward the inner circumferential surface and extends upward.

[0029] As an example, at least the surface of the wafer guide portion 12 is formed from poly-SiC. The wafer guide portion 12 may be configured to be entirely formed from poly-SiC, or may be configured to be formed from graphite with a SiC coating on the surface. However, when the wafer W rotates via the support table 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, because the wafer guide portion 12 is unsuitable for regeneration by polishing, which will be described later, it is preferable that the wafer guide portion 12 be configured to be entirely formed from poly-SiC.

[0030] The lifting unit 15 can move up and down in the axial direction. The lifting unit 15 is axially shaped and extends axially around the central axis J. The lifting unit 15 has a cylindrical holder 15A at its upper end. The diameter of the holder 15A is smaller than the diameter of the through-hole 11B in the support table 11. The holder 15A is disposed below the wafer W when the lifting unit 15 is in the lowered position. In other words, the lowered position of the lifting unit 15 is a position where the holder 15A is below the wafer W. 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. When the lifting unit 15 is in the upper position to remove the wafer W from the wafer support device 10, the holder 15A moves the wafer W above the support surface 11A while holding the underside of the wafer W.

[0031] In the SiC epitaxial growth apparatus 1 having the above-described configuration, the gas containing the source gas G introduced into the film formation space K of the reactor member 3 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.

[0032] 4 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. 4. In addition, a deposit DP, which is a reaction product, accumulates on the wafer guide portion 12.

[0033] In the process of supplying the film-forming raw material and causing it to adhere and deposit on the wafer W, the raw material that reaches the wafer guide portion 12 moves, aggregates, and deposits due to the migration effect. At this time, if an inflection point exists in the wafer guide portion 12, it is thought that the movement slows down and the deposit DP becomes thicker as a result of being trapped. Therefore, in the wafer guide portion 12 having the first chamfered portion 13 and the second chamfered portion 14, the deposit DP grows and accumulates to the greatest thickness at the intersection of the upper surface 12a and the first inclined surface 13a, which are the inflection points, and at the intersection of the upper surface 12a and the second inclined surface 14a.

[0034] FIG. 5 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 and the second chamfered portion 14 is used.

[0035] 5, in the wafer guide portion 12N that does not have the first chamfered portion 13 and the second chamfered portion 14, the deposits DP grow and accumulate most thickly at the inflection points where the top surface 12a and the inner peripheral surface 12b intersect and where the top surface 12a and the outer peripheral surface 12c intersect. 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.

[0036] In this case, when the wafer W is raised by the lifting unit 15 to remove the wafer W 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, causing scattering and dust generation, which may become a cause of 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.

[0037] At this time, the intersection of the upper surface 12a and the inner surface 12b, which is the inflection point, and the intersection of the upper surface 12a and the outer surface 12c are both right angles and have an edge shape, so there is a possibility that defects such as cracks may occur in the wafer guide portion 12N.

[0038] In contrast, in the wafer guide portion 12 of the wafer support device 10 of the embodiment, the first chamfered portion 13 and the second chamfered portion 14 are provided, so that the intersection angle between the inner peripheral surface 12b and the first inclined surface 13a, the intersection angle between the first inclined surface 13a and the top surface 12a, the intersection angle between the top surface 12a and the second inclined surface 14a, and the intersection angle between the second inclined surface 14a and the outer peripheral surface 12c are all obtuse angles. Therefore, compared to the wafer guide portion 12N, which has a right-angle intersection at an inflection point that is prone to stress concentration, the obtuse angle at the intersection at 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 remanufactured while suppressing the occurrence of cracks on both the inner peripheral surface 12b and the outer peripheral surface 12c.

[0039] 3, the thickness H1 of the wafer guide portion 12 in the direction along the central axis J is preferably 1.5 mm or more and 2.0 mm or less. If the thickness H1 of the wafer guide portion 12 is less than 1.5 mm, the deposition of deposits DP on the upper surface 12a may cause the wafer guide portion 12 to warp, and cracks may easily occur during reclaiming processing. If the thickness H1 of the wafer guide portion 12 exceeds 2.0 mm, the wafer guide portion 12 located above the first surface Wa of the wafer W may act as a barrier, hindering the flow of source gas G radially outward along the first surface Wa of the wafer W.

[0040] 6 is a diagram showing the in-plane distribution of the SiC epitaxial film (epitaxial film) Wb when the wafer guide portion 12 acts as a barrier. As shown in FIG. 6, the flow of the source gas G is obstructed on the radially outer side, causing turbulence, which may result in a thinner film thickness of the SiC epitaxial film Wb at the peripheral edge of the wafer W and a lower in-plane distribution. Furthermore, considering the thickness T1 (e.g., 300 to 600 μm) of a 6-inch or 8-inch wafer W, the wafer guide portion 12 may become thicker than necessary, resulting in increased costs.

[0041] By setting the thickness H1 of the wafer guide portion 12 to 1.5 mm or more and 2.0 mm or less, it is possible to suppress an increase in cost while reducing warpage of the wafer guide portion 12 and suppressing cracking of the wafer guide portion 12 during epitaxial growth processing and reclaiming processing. It is also possible to suppress a decrease in the in-plane film thickness distribution of the SiC epitaxial film Wb.

[0042] The angle of the first chamfered portion 13 and the angle of the second chamfered portion 14 relative to the horizontal direction are preferably 10 degrees or more and 45 degrees or less. If the angle of the first chamfered portion 13 relative to the horizontal direction is less than 10 degrees, the intersection angle between the inner peripheral surface 12b and the first chamfered portion 13 approaches a right-angle edge shape, which may cause cracks in the wafer guide portion 12 during reclaiming processing of the inner peripheral surface 12b. In addition, the deposit DP may easily protrude toward the central axis J from the inner peripheral surface 12b, which may cause the edge of the wafer W to come into contact with the deposit DP during transport, resulting in transport failure.

[0043] Similarly, if the angle of the second chamfered portion 14 with respect to the horizontal direction is less than 10 degrees, the intersection angle between the outer peripheral surface 12c and the second chamfered portion 14 approaches a right-angle edge shape, which may cause cracks in the wafer guide portion 12 during reclaiming of the outer peripheral surface 12c. In addition, the 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, which may result in particles.

[0044] Furthermore, if the angle of the first chamfered portion 13 with respect to the horizontal direction exceeds 45 degrees, the wafer guide portion 12 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 in-plane thickness distribution of the SiC epitaxial film Wb may be reduced. Therefore, by setting the angles of the first chamfered portion 13 and the second chamfered portion 14 with respect to the horizontal direction to be between 10 degrees and 45 degrees, cracks in the wafer guide portion 12, transport problems with the wafer W, particle generation, and a reduction in the in-plane thickness distribution of the SiC epitaxial film Wb during reclamation processing can be suppressed.

[0045] The first distance H4 between the first surface Wa facing upward on the wafer W and the upper surface 12a in the direction along the central axis J is preferably 1 mm or more and 2 mm or less. If the first distance H4 between the first surface Wa and the upper surface 12a is less than 1 mm, the edge of the wafer W may lift up if warping occurs in the wafer W due to high temperatures. In this case, when the wafer W rotates on 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. If the first distance H4 between the first surface Wa and the upper surface 12a exceeds 2 mm, as described above, the flow of the source gas G is obstructed at the radially outer side, causing turbulence, which may result in a thinner SiC epitaxial film Wb and a lower in-plane thickness distribution. Therefore, by setting the first distance H4 between the first surface Wa and the upper surface 12a to 1 mm or more and 2 mm or less, it is possible to suppress the wafer W from protruding from the wafer guide portion 12 and the decrease in the in-plane distribution of the film thickness of the SiC epitaxial film Wb.

[0046] The second distance W1 in the radial direction about the central axis J between the intersection of the first chamfered portion 13 and the upper surface 12a and the inner circumferential surface 12b is preferably 0.5 mm or more and 10 mm or less. If the second distance W1 between the intersection of the first chamfered portion 13 and the upper surface 12a and the inner circumferential surface 12b is less than 0.5 mm, the wafer guide portion 12 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 in-plane thickness distribution of the SiC epitaxial film Wb may be reduced.

[0047] If the second distance W1 between the intersection of the first chamfered portion 13 and the upper surface 12a and the inner peripheral surface 12b exceeds 10 mm, the intersection angle between the inner peripheral surface 12b and the first chamfered portion 13 approaches a right-angle edge shape, which may cause cracks in the wafer guide portion 12 during reclamation of the inner peripheral surface 12b. Furthermore, the deposit DP may easily protrude toward the central axis J from the inner peripheral surface 12b, potentially resulting in contact with the deposit DP during wafer W transport and resulting in transport problems. Therefore, by setting the second distance W1 between the intersection of the first chamfered portion 13 and the upper surface 12a and the inner peripheral surface 12b to 0.5 mm or more and 10 mm or less, it is possible to suppress a decrease in the in-plane film thickness distribution of the SiC epitaxial film Wb, cracks in the wafer guide portion 12 during reclamation, and transport problems of the wafer W.

[0048] The position along the central axis J where the inner circumferential surface 12b and the first chamfered portion 13 intersect is preferably above the position of the first surface Wa, which faces upward on the wafer W. If the position where the inner circumferential surface 12b and the first chamfered portion 13 intersect is the same as or below the position of the first surface Wa, high temperatures may cause the wafer W to warp, causing the edge of the wafer W to lift up. In this case, when the wafer W rotates on the support table 11 during epitaxial growth processing, centrifugal force may cause the wafer W to move and jump out of the wafer guide portion 12. Therefore, by positioning the position where the inner circumferential surface 12b and the first chamfered portion 13 intersect above the position of the first surface Wa, the wafer W can be prevented from jumping out of the wafer guide portion 12.

[0049] In the SiC epitaxial growth process described above, the timing for replacing the wafer guide unit 12 due to the accumulation of deposits DP is preferably when the maximum axial distance H5 between the first surface Wa of the wafer W and the deposits DP is 2.5 mm or less, as shown in FIG. 4 . If the maximum distance H5 between the first surface Wa of the wafer W and the deposits DP exceeds 2.5 mm, the deposits DP will accumulate too much, resulting in increased effort for reclamation processing. Furthermore, depending on the state of accumulation of the deposits DP, the deposits DP may protrude radially inward from the inner circumferential surface 12 b or radially outward from the outer circumferential surface 12 c. Replacing the wafer guide unit 12 when the maximum distance H5 between the first surface Wa and the deposits DP is 2.5 mm or less reduces the effort for reclamation processing of the wafer guide unit 12 and suppresses wafer W transport failures.

[0050] According to at least one of the embodiments described above, by providing a first chamfered portion 13 that connects the inner peripheral surface 12b and the upper surface 12a of the wafer guide portion 12 and extends upward from the inner peripheral surface 12b toward the outer peripheral side, and a second chamfered portion 14 that connects the outer peripheral surface 12c and the upper surface 12a of the wafer guide portion 12 and extends upward from the outer peripheral surface 12c toward the inner peripheral side, damage to the wafer guide portion 12 during regeneration can be suppressed.

[0051] Furthermore, according to at least one embodiment, by setting the thickness H1 of the wafer guide portion 12 to 1.5 mm or more and 2.0 mm or less, damage to the wafer guide portion 12 during regeneration and a decrease in the in-plane distribution of the film thickness of the SiC epitaxial film Wb can be suppressed while suppressing cost increases.

[0052] Furthermore, according to at least one embodiment, by setting the angle of the first chamfered portion 13 and the angle of the second chamfered portion 14 relative to the horizontal direction to be greater than or equal to 10 degrees and less than or equal to 45 degrees, damage to the wafer guide portion 12 during regeneration, problems with transport of the wafer W, generation of particles, and a decrease in the in-plane film thickness distribution of the SiC epitaxial film Wb can be suppressed.

[0053] Furthermore, according to at least one embodiment, by setting the first distance H4 between the first surface Wa and the upper surface 12a to 1 mm or more and 2 mm or less, it is possible to suppress the wafer W from protruding from the wafer guide portion 12 and the decrease in the in-plane distribution of the film thickness of the SiC epitaxial film Wb.

[0054] Furthermore, according to at least one embodiment, by setting the second distance W1 between the intersection of the first chamfered portion 13 and the upper surface 12a and the inner surface 12b to 0.5 mm or more and 10 mm or less, it is possible to suppress a decrease in the in-plane distribution of the film thickness of the SiC epitaxial film Wb, damage to the wafer guide portion 12 during regeneration, and poor transport of the wafer W.

[0055] Furthermore, according to at least one embodiment, by positioning the position where the inner peripheral surface 12b and the first chamfered portion 13 intersect above the position of the first surface Wa, it is possible to prevent the wafer W from protruding from the wafer guide portion 12.

[0056] This embodiment includes the following supplementary aspects: (Supplementary Note 1) A wafer support device comprising: a support table having a support surface that supports a wafer; an annular wafer guide portion that surrounds the periphery of the wafer supported on the support surface, centered on a central axis that extends in a normal direction to the support surface; a first chamfered portion that connects an inner peripheral surface to an upper surface of the wafer guide portion and extends upward as it moves from the inner peripheral surface to the outer peripheral side; and a second chamfered portion that connects the outer peripheral surface to the upper surface of the wafer guide portion and extends upward as it moves from the outer peripheral surface to the inner peripheral side. (Supplementary Note 2) The wafer support device according to Supplementary Note 1, wherein, in a cross section including the central axis, the first chamfered portion comprises a first inclined surface that slopes upward as it moves from the inner peripheral surface to the outer peripheral side, and the second chamfered portion comprises a second inclined surface that slopes upward as it moves from the outer peripheral surface to the inner peripheral side. (Supplementary Note 3) The wafer support device according to Supplementary Note 1 or Supplementary Note 2, wherein the thickness of the wafer guide portion in the direction along the central axis is 1.5 mm or more and 2.0 mm or less. (Supplementary Note 4) The wafer support device according to any one of Supplementary Note 1 to Supplementary Note 3, wherein a first distance in the direction along the central axis between a first surface of the wafer facing upward and the top surface is 1 mm or more and 2 mm or less. (Supplementary Note 5) The wafer support device according to any one of Supplementary Note 1 to Supplementary Note 4, wherein a second distance in the radial direction about the central axis between an intersection of the first chamfered portion and the top surface and the inner peripheral surface is 0.5 mm or more and 10 mm or less. (Supplementary Note 6) The wafer support device according to any one of Supplementary Note 1 to Supplementary Note 5, wherein a position in the direction along the central axis where the inner peripheral surface and the first chamfered portion intersect is above the position of the first surface of the wafer facing upward. (Supplementary Note 7) The wafer support device according to any one of Supplementary Notes 1 to 6, wherein the angle of the first chamfered portion and the angle of the second chamfered portion relative to the horizontal direction are 10 degrees or more and 45 degrees or less. (Supplementary Note 8) The wafer support device according to any one of Supplementary Notes 1 to 7, wherein at least the surface of the wafer guide portion is made of poly-SiC. (Supplementary Note 9) A SiC epitaxial growth apparatus comprising the wafer support device according to any one of Supplementary Notes 1 to 8.

[0057] 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.

[0058] REFERENCE SIGNS LIST 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, 14...second chamfered portion, 14a...second inclined surface, J...central axis, W...wafer, Wa...first surface

Claims

1. A wafer support device comprising: a support table having a support surface for supporting a wafer; a circular wafer guide portion surrounding the periphery of the wafer supported on the support surface, centered on a central axis extending in a normal direction to the support surface; a first chamfered portion connecting an inner peripheral surface and an upper surface of the wafer guide portion, and extending in an upward direction from the inner peripheral surface toward the outer peripheral side; and a second chamfered portion connecting an outer peripheral surface and the upper surface of the wafer guide portion, and extending in an upward direction from the outer peripheral surface toward the inner peripheral side.

2. A wafer support device as described in claim 1, wherein, in a cross section including the central axis, the first chamfered portion has a first inclined surface that inclines upward as it moves from the inner circumferential surface to the outer circumferential surface, and in the cross section, the second chamfered portion has a second inclined surface that inclines upward as it moves from the outer circumferential surface to the inner circumferential surface.

3. The wafer support device according to claim 1 or 2, wherein the thickness of said wafer guide portion in the direction along said central axis is 1.5 mm or more and 2.0 mm or less.

4. The wafer supporting device according to claim 1 or 2, wherein a first distance in a direction along the central axis between a first surface of the wafer facing upward and the top surface is 1 mm or more and 2 mm or less.

5. A wafer support device as described in claim 1 or 2, wherein a second radial distance centered on the central axis between an intersection of said first chamfered portion and said upper surface and said inner circumferential surface is 0.5 mm or more and 10 mm or less.

6. A wafer supporting device as described in claim 1 or 2, wherein the position along the central axis where the inner peripheral surface and the first chamfered portion intersect is above the position of a first surface of the wafer that faces upward.

7. A wafer supporting device according to claim 1 or 2, wherein an angle of the first chamfered portion and an angle of the second chamfered portion with respect to the horizontal direction are equal to or greater than 10 degrees and equal to or less than 45 degrees.

8. The wafer supporting device according to claim 1 or 2, wherein at least the surface of said wafer guide portion is made of poly-SiC.

9. A SiC epitaxial growth apparatus comprising the wafer support device according to claim 1 or 2.

Images