Film forming method, susceptor, and vapor phase growth apparatus

Abstract

Provided are a film formation method, a susceptor, and a vapor phase growth apparatus capable of suppressing a reduction in yield of a semiconductor device manufactured using a wafer. A film forming method according to an embodiment is a film forming method for forming a film on a surface of a wafer using a vapor phase growth apparatus. The film forming method according to an embodiment includes a film forming process of forming a film on a surface of the wafer. The vapor phase growth device is provided with a base for supporting the wafer. The base is provided with a plurality of wafer supporting parts for supporting the wafer from the lower side, and rotates around a rotation axis extending in the vertical direction. The plurality of wafer supporting parts are arranged at intervals in the circumferential direction around the rotation axis. The film forming process includes a process of supporting the wafer by the plurality of wafer support portions such that directions in which the rotation axis and each of the wafer support portions are connected when viewed in a vertical direction are different from a cleavage direction of the wafer.

Description

[0001] Related Application

[0002] This application claims priority to Japanese Patent Application No. 2024-149982 (Filing Date: August 30, 2024). This application incorporates the entire contents of the base application by reference thereto TECHNICAL FIELD

[0003] Embodiments of the present application relate to a film forming method, a susceptor, and a vapor phase growth apparatus. BACKGROUND

[0004] A vapor phase growth apparatus for forming a film on a surface of a wafer supported from a lower side by a susceptor is known. In a film forming process in which a film is formed on a surface of a wafer in the vapor phase growth apparatus as described above, the wafer is supported from a lower side by a ring-shaped wafer support portion possessed by the susceptor. Therefore, due to heat transmitted from the wafer support portion, the temperature of a portion of the wafer on an outer circumferential side is likely to increase compared to a central portion of the wafer. Therefore, there is a problem that, in the portion of the wafer on the outer circumferential side, the in-plane distribution of the film formed on the wafer deteriorates, and the yield of semiconductor devices manufactured using the wafer decreases. SUMMARY

[0005] Embodiments of the present application provide a film forming method, a susceptor, and a vapor phase growth apparatus capable of suppressing a decrease in the yield of semiconductor devices manufactured using a wafer.

[0006] The film forming method of the embodiment is a film forming method of forming a film on a surface of a wafer using a vapor phase growth apparatus. The film forming method of the embodiment includes a film forming process of forming a film on a surface of a wafer. The vapor phase growth apparatus has a susceptor that supports the wafer. The susceptor has a plurality of wafer support portions that support the wafer from a lower side, and the susceptor rotates around a rotation axis that extends in a vertical direction. The plurality of wafer support portions are arranged at intervals in a circumferential direction around the rotation axis. The film forming process includes a process of supporting the wafer by the plurality of wafer support portions so that, when viewed in the vertical direction, directions in which the rotation axis is connected to each of the wafer support portions respectively become directions different from a cleavage direction of the wafer. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 is a cross-sectional view that shows a vapor phase growth apparatus of the first embodiment.

[0008] Figure 2 is a cross-sectional view that shows a part of a vapor phase growth apparatus of the first embodiment.

[0009] Figure 3 is a view that shows a part of a vapor phase growth apparatus of the first embodiment as viewed from an upper side.

[0010] Figure 4 is a view showing a bottom surface of a hexagonal crystal lattice of a wafer.

[0011] Figure 5 is a sectional view showing a part of a vapor deposition apparatus of the first embodiment when a wafer is transported.

[0012] Figure 6 is a sectional view showing a part of a susceptor and a wafer guide portion of the first embodiment.

[0013] Figure 7 is Figure 6 is a sectional view of VII-VII in

[0014] Figure 8 is a view showing a positional relationship between a crystal orientation of a wafer and a plurality of wafer support portions of the first embodiment.

[0015] Figure 9 is a view showing a positional relationship between a measurement portion of a wafer after film formation and a plurality of wafer support portions of the first embodiment.

[0016] Figure 10 is a block diagram showing a part of a vapor deposition apparatus of the first embodiment.

[0017] Figure 11 is a flowchart showing one example of a sequence of a film formation method of forming a film on a surface of a wafer using the vapor deposition apparatus of the first embodiment.

[0018] Figure 12 is a view showing a plurality of wafer support portions in a modified example of the first embodiment.

[0019] Figure 13 is a view showing a susceptor in the second embodiment as viewed from the upper side.

[0020] Figure 14 is a view showing a susceptor in the third embodiment as viewed from the upper side. DETAILED DESCRIPTION

[0021] Hereinafter, a film forming method, a susceptor, and a vapor deposition apparatus according to an embodiment will be described with reference to the drawings. In the drawings, a Z-axis indicating a vertical direction is appropriately shown. A side to which an arrow of the Z-axis is directed (+Z side) is an upper side in the vertical direction, and a side opposite to the side to which the arrow of the Z-axis is directed (-Z side) is a lower side in the vertical direction. In the following description, the vertical direction will be referred to as "vertical direction Z", the upper side in the vertical direction Z will be simply referred to as "upper side", and the lower side in the vertical direction Z will be simply referred to as "lower side". In addition, in the drawings, a rotation axis R extending in the vertical direction Z is appropriately shown. The rotation axis R is an imaginary line. In the following description, a radial direction with the rotation axis R as the center will be simply referred to as "radial direction", and a circumferential direction around the rotation axis R will be simply referred to as "circumferential direction", unless otherwise specified.

[0022] (First Embodiment)

[0023] Figure 1 is a cross-sectional view showing the vapor deposition apparatus 10 according to the first embodiment. Figure 2 is a cross-sectional view showing a part of the vapor deposition apparatus 10 according to the first embodiment. Figure 3 is a view showing a part of the vapor deposition apparatus 10 according to the first embodiment, as viewed from the upper side. In addition, in Figure 3 , an outline of the wafer W is shown by a double-dot chain line. Figures 1 to 3 The vapor deposition apparatus 10 shown in is a device for forming a film on a surface of a wafer W. In the vapor deposition apparatus 10, an epitaxial film is formed on the surface of the wafer W, for example, by a CVD (Chemical Vapor Deposition) method. The film formed on the surface of the wafer W is, for example, a film composed of silicon carbide (SiC), that is, a SiC film. The film formed on the surface of the wafer W can also be a film composed of another material such as Si. In the first embodiment, the wafer W is formed of a single crystal having a crystal structure of hexagonal system. The wafer W is formed of, for example, silicon carbide (SiC). That is, the wafer W is a SiC substrate. The material forming the wafer W is, for example, 4H-SiC, 6H-SiC, or the like. The wafer W can be formed of another material such as silicon (Si).

[0024] As shown in Figure 3 , the wafer W is substantially a circular plate. A part of an outer edge of the wafer W is a flat orientation plane portion Wd extending in a straight line. That is, in the first embodiment, the flat orientation plane portion Wd is provided at the outer edge of the wafer W. In the first embodiment, the flat orientation plane portion Wd extends in one direction of a cleavage direction of the wafer W. The "cleavage direction" is a direction in which the wafer W is easily broken, and is a direction determined by a crystal structure of a crystal constituting the wafer W. The cleavage direction of the wafer W is a direction along a cleavage plane formed when the wafer W is broken along the cleavage direction. Figure 4 is a view showing a bottom surface of a lattice Rw of hexagonal system forming the wafer W. As shown in , the wafer W is formed of a single crystal having a crystal structure of hexagonal system. The wafer W is formed of, for example, silicon carbide (SiC). That is, the wafer W is a SiC substrate. The material forming the wafer W is, for example, 4H-SiC, 6H-SiC, or the like. The wafer W can be formed of another material such as silicon (Si).Figure 4 In the crystal structure of the hexagonal system, as shown in the drawing, a direction indicated by four unit vectors of an al vector, an a2 vector, an a3 vector, and a c vector, which are taken from the center of the base surface of the crystal lattice Rw as the origin, is expressed by a direction index of a Miller index using the smallest integer ratio of the coefficients of the respective unit vectors. Here, the plate surface of the wafer W is a surface that is substantially along the crystal plane indicated by (0001) in the plane index of the Miller index. In other words, the wafer W is a wafer formed of a substrate that is a substrate in which the C plane of the crystal lattice indicated by (0001) is substantially along the plate surface of the wafer W, that is, a substrate in which the orientation becomes C(0001). Here, the case where the plate surface of the wafer W is "substantially" along the crystal plane indicated by (0001) includes, for example, the case of a SiC substrate with an off-angle in which the plate surface is deviated from the (0001) surface by several degrees in order to stabilize the crystal structure of the film for epitaxial growth. In the SiC substrate with the off-angle, the off-angle is, for example, about 1° or more and 4° or less. The al vector, the a2 vector, and the a3 vector are unit vectors indicating directions from the origin O toward respective atoms that define the outer periphery of the base surface of the crystal lattice Rw. In the case where the plate surface of the wafer W is substantially along the crystal plane indicated by (0001), the al vector, the a2 vector, and the a3 vector are vectors in directions that are substantially along the plate surface of the wafer W. The sum of the coefficient of the al vector, the coefficient of the a2 vector, and the coefficient of the a3 vector becomes zero. The c vector is a unit vector indicating a direction orthogonal to the al vector, the a2 vector, and the a3 vector. In the case where the plate surface of the wafer W is substantially along the crystal plane indicated by (0001), the c vector is a vector in a direction substantially parallel to the plate thickness direction of the wafer W.

[0025] For example, in Figure 4 , a crystal orientation indicated by [11-20] indicates that the coefficient of the al vector, the coefficient of the a2 vector, the coefficient of the a3 vector, and the coefficient of the c vector are 1:1:-2:0. Further, in the Miller index, in the case where the coefficient is negative, a horizontal line is added above the number to indicate, but in the drawing, instead of adding the horizontal line above the number, a "-" is added before the number to indicate the case where the coefficient is negative. In Figure 4 , six crystal orientations of [11-20], [-12-10], [-2110], [-1-120], [1-210], [2-1-10] are shown. The six crystal orientations are equivalent directions to each other, and are collectively indicated as <11-20>. A crystal orientation equivalent to a certain crystal orientation is a crystal orientation that becomes the same direction as a certain crystal orientation if the crystal is rotated, and is a crystal orientation that cannot be distinguished. In the hexagonal system, a crystal orientation indicated by <11-20> is a direction in which the crystal is easily broken, that is, a cleavage direction. In the first embodiment, the oriented plane portion Wd extends in the crystal orientation of the wafer W indicated by <11-20>. As Figure 3As shown, the portion of the outer edge of the wafer W other than the oriented flat portion Wd is in a circular arc shape. The wafer W is disposed in the vapor phase growth apparatus 10 in a state in which the surface Wa on which the film is to be formed faces upward, and the back surface Wb opposite the surface Wa faces downward. Further, even if the wafer W is the SiC substrate with the above-described misorientation angle, the direction of <11-20> when viewed in the plate thickness direction of the wafer W is the same or substantially the same as the case in which the wafer W is the SiC substrate with the misorientation angle of 0°.

[0026] As shown, the vapor phase growth apparatus 10 has a chamber 20, a supply pipe 24, a susceptor 30, a wafer guide portion 40, a first heating portion 51, a second heating portion 52, a third heating portion 53, and a drive portion 60. Figure 1

[0027] The chamber 20 houses the supply pipe 24, the susceptor 30, the wafer guide portion 40, the first heating portion 51, the second heating portion 52, the third heating portion 53, and the drive portion 60 in the inside. The chamber 20 is, for example, a metal such as stainless steel (SUS). The chamber 20 is a cylindrical shape extending in the vertical direction Z. A supply port 21 is formed in the ceiling of the chamber 20. A discharge port 22 is formed in the bottom of the chamber 20. A gas G including a raw material gas for forming a film on the wafer W is supplied from the supply port 21 to the inside of the chamber 20.

[0028] The supply pipe 24 is a cylindrical shape extending in the vertical direction Z. The supply pipe 24 is open at both the upper side and the lower side. The gas G supplied from the supply port 21 to the inside of the chamber 20 flows downward in the inside of the supply pipe 24. The gas G flowing downward in the inside of the supply pipe 24 is supplied to the wafer W placed on the susceptor 30. Excess gas G among the gas G supplied to the inside of the chamber 20 is discharged to the outside of the chamber 20 from the discharge port 22.

[0029] The raw material gas included in the gas G reacts on the surface of the wafer W, thereby forming an epitaxial film on the surface of the wafer W. The raw material gas is, for example, a gas including a Si-based gas and a C-based gas. The Si-based gas is, for example, silane (SiH4), dichlorosilane (SiH2Cl2), trichlorosilane (SiHCl3), tetrachlorosilane (SiCl4), or the like. The C-based gas is, for example, propane (C3H8) or the like. In the first embodiment, the raw material gas is, for example, a gas including silane (SiH4) and propane (C3H8).

[0030] ​In the first embodiment, a working gas other than the raw material gas is supplied to the chamber 20 from the supply port 21. Examples of such working gases include impurity gases, carrier gases, and hydrogen chloride (HCl) gas. Examples of impurity gases include gases containing N-type impurities such as nitrogen and gases containing P-type impurities such as TMA (trimethylaluminum). The carrier gas is, for example, argon or hydrogen. More specifically, argon is used as the carrier gas when the wafer W is placed into the vapor phase growth apparatus 10 and mounted on the substrate 30, and when the wafer W after film deposition is removed from the substrate 30 and removed from the vapor phase growth apparatus 10. Hydrogen is used as the carrier gas during film deposition.

[0031] The base 30 is a support component that supports the wafer W from below. The base 30 is supported from below by the drive unit 60. Figure 2 As shown, the base 30 has a base 31, a movable portion 32, and a plurality of wafer support portions 34. The base 31, the movable portion 32, and the plurality of wafer support portions 34 are independent of each other. The base 31, the movable portion 32, and the plurality of wafer support portions 34 are, for example, made of polycrystalline silicon carbide (poly-SiC). The base 31, the movable portion 32, and the plurality of wafer support portions 34 may also be made of graphite. In this case, a coating made of SiC can be provided on each surface of the base 31, the movable portion 32, and the plurality of wafer support portions 34.

[0032] In the first embodiment, the base 31 is annular, surrounding the axis of rotation R. The base 31 has an inner annular portion 33 and a guide support portion 35. Figure 3 As shown, the inner annular portion 33 is an annular shape that surrounds the rotation axis R. In the first embodiment, the radial inner edge of the inner annular portion 33 is the radial inner edge of the base 31.

[0033] The guide support portion 35 is located radially outward from the inner annular portion 33. In the first embodiment, the guide support portion 35 is an annular shape surrounding the rotation axis R. More specifically, the guide support portion 35 is a generally circular annular shape centered on the rotation axis R. The guide support portion 35 is the portion that supports the wafer guide portion 40 from below. Figure 2 As shown, in the first embodiment, the radially inner edge of the guide support portion 35 is connected to the radially outer edge of the inner annular portion 33. The upper surface of the guide support portion 35 is located above the upper surface of the inner annular portion 33. The lower surface of the wafer guide portion 40 contacts the radially outer portion of the upper surface of the guide support portion 35.

[0034] The movable section 32 is arranged radially inside the inner annular section 33 of the base section 31. The movable section 32 is fitted radially inside the inner annular section 33 of the base section 31. In a state where the wafer W is placed on the susceptor 30, the back surface Wb of the wafer W is arranged separated upward from the upper surface of the inner annular section 33 and the upper surface of the movable section 32. A gap is provided between the wafer W and the inner annular section 33 in the vertical direction Z and between the wafer W and the movable section 32 in the vertical direction Z.

[0035] The movable section 32 is movable in the vertical direction Z. Figure 5 is a cross-sectional view showing a part of the vapor deposition apparatus 10 when the wafer W is transported. As shown in Figure 5 , the movable section 32 is moved upward compared to the inner annular section 33 when the wafer W is transported. In the first embodiment, the movable section 32 is moved in the vertical direction Z by the lifting section 80. The lifting section 80 has a plurality of movable pins 81 located at the lower side of the movable section 32. The lifting section 80 moves the plurality of movable pins 81 upward, and the plurality of movable pins 81 push the movable section 32 upward from the lower side, thereby moving the movable section 32 upward. The plurality of movable pins 81 pass through the gap provided in the second heating section 52 and are moved upward compared to the second heating section 52, thereby pushing the movable section 32 upward.

[0036] When the wafer W is transported to the susceptor 30, the wafer W transported by the transport section 100 is placed on the movable section 32 located upward compared to the inner annular section 33. If the movable section 32 is moved downward by the lifting section 80 in this state, the radially outer portion of the wafer W is supported from the lower side by the wafer support section 34, and the wafer W is placed on the susceptor 30. When the wafer W is transported from the susceptor 30, the movable section 32 is raised, and the wafer W is lifted to the upper side compared to the wafer support section 34 and the wafer guide section 40 by the movable section 32. In this state, the wafer W is transported from the movable section 32 by the transport section 100.

[0037] As shown in Figure 3 , the base section 31 has a plurality of fixed hole sections 35a opened at the upper side. The plurality of fixed hole sections 35a are arranged at intervals in the circumferential direction. In the first embodiment, the plurality of fixed hole sections 35a are arranged at equal intervals in the circumferential direction over one turn. In the first embodiment, the number of the plurality of fixed hole sections 35a is four. In the first embodiment, the fixed hole section 35a is a hole of a circular shape when viewed in the vertical direction Z. In the first embodiment, the fixed hole section 35a is formed in the radially inner portion of the guide section support section 35. Figure 6 is a cross-sectional view showing a part of the susceptor 30 and a part of the wafer guide section 40. As shown in Figure 6As shown, the fixing hole portion 35a is recessed downward from the upper surface of the guide support portion 35. The fixing hole portion 35a is a hole with a bottom on the lower side. Alternatively, the fixing hole portion 35a may be a hole that passes through the base portion 31 in the vertical direction Z.

[0038] like Figure 3 As shown, a marking portion 36 is formed on the base 31. The marking portion 36 indicates a predetermined direction, which is the direction along which the orientation plane portion Wd, provided on the outer edge of the wafer W, runs when the wafer W is supported by a plurality of wafer support portions 34. This predetermined direction is orthogonal to the vertical direction Z. Figure 3 In the middle, the specified direction is Figure 3 The left-right direction is indicated by arrow D. In the following description, the predetermined direction indicated by the marking portion 36 is referred to as "predetermined direction D". In the first embodiment, the marking portion 36 is a mark extending in the predetermined direction D. The marking portion 36 is formed in the radially inner portion of the upper surface of the guide support portion 35. In the first embodiment, when the wafer W is placed on the base 30, the marking portion 36 is located below the radially inner portion of the radially outer edge of the wafer W located in the orientation plane portion Wd. That is, in the first embodiment, the marking portion 36 is covered by the wafer W from above.

[0039] Multiple wafer support portions 34 support the wafer W from below. Multiple wafer support portions 34 support the outer periphery of the wafer W from below. Multiple wafer support portions 34 support the radially outer portion of the wafer W from below. More specifically, multiple wafer support portions 34 support the portion of the wafer W closest to the radially outer edge from below. The multiple wafer support portions 34 are arranged at intervals in the circumferential direction about the rotation axis R. In the first embodiment, the multiple wafer support portions 34 are arranged at equal intervals covering the entire circumference. In the first embodiment, the number of multiple wafer support portions 34 is four.

[0040] like Figure 6 As shown, in the first embodiment, the plurality of wafer support portions 34 are columnar extending in the vertical direction Z. The plurality of wafer support portions 34 are respectively fixed inside the plurality of fixing holes 35a. In the first embodiment, the lower portion of each wafer support portion 34 is fixed inside the respective fixing hole 35a. Each wafer support portion 34 is fixed inside the respective fixing hole 35a, for example, by pressing. The plurality of wafer support portions 34 protrude upwards from the interior of the plurality of fixing holes 35a. That is, the upper end of each wafer support portion 34 is located above the upper end of each fixing hole 35a. The upper end of each wafer support portion 34 contacts the back surface Wb of the wafer W.

[0041] The plurality of wafer support portions 34 each have a main body portion 34a and a protruding portion 34b. The main body portion 34a is a columnar shape extending in the vertical direction Z. Figure 7 is a cross-sectional view of the wafer support portion 34, and is Figure 6 a VII-VII cross-sectional view in FIG. 7. As shown in Figure 7 , in the first embodiment, the main body portion 34a is a cylindrical shape extending in the vertical direction Z with the center axis J as the center. The center axis J is an imaginary line extending in the vertical direction Z. The outer diameter of the main body portion 34a is smaller than the inner diameter of the fixing hole portion 35a. The outer peripheral surface of the main body portion 34a is disposed apart from the inner surface of the fixing hole portion 35a. As shown in Figure 6 , the lower side surface of the main body portion 34a is in contact with the bottom surface of the fixing hole portion 35a. The lower side surface of the main body portion 34a is, for example, a plane orthogonal to the vertical direction Z. The upper side surface of the main body portion 34a is in contact with the back surface Wb of the wafer W. The upper side surface of the main body portion 34a is, for example, a plane orthogonal to the vertical direction Z.

[0042] Further, the upper side surface of the main body portion 34a may, for example, be a circular arc shape protruding upward in a cross section including the center axis J. In other words, the upper side end portion of the main body portion 34a may, for example, be a semispherical shape protruding upward. In addition, the upper side end portion of the main body portion 34a may, for example, be a conical shape protruding upward or a pyramidal shape protruding upward. In these cases, the apex in the upper side end portion of the main body portion 34a is in contact with the back surface Wb of the wafer W.

[0043] The protruding portion 34b is provided to the outer peripheral surface of the main body portion 34a. The outer peripheral surface of the main body portion 34a is a surface on the outer side in the radial direction with the center axis J as the center among the outer surfaces of the main body portion 34a. Further, in the following description, the radial direction with the center axis J as the center is sometimes referred to as the "second radial direction". The protruding portion 34b protrudes from the outer peripheral surface of the main body portion 34a to the outer side in the second radial direction. As shown in Figure 7 , in the first embodiment, the surface on the outer side in the second radial direction of the protruding portion 34b is a circular arc shape protruding to the outer side in the second radial direction in a cross section orthogonal to the vertical direction Z. In the first embodiment, the protruding portion 34b is a semicircular shape protruding to the outer side in the second radial direction in a cross section orthogonal to the vertical direction Z. As shown in Figure 6 , in the first embodiment, the protruding portion 34b is a rib extending in the vertical direction Z. The upper side end portion of the protruding portion 34b is located on the lower side than the upper side end portion of the main body portion 34a. The lower side end portion of the protruding portion 34b is located on the upper side than the lower side end portion of the main body portion 34a. The lower side end portion of the protruding portion 34b is a tapered portion 34c in which the dimension in the second radial direction becomes smaller as it goes toward the lower side. The lower side portion in the protruding portion 34b is located inside the fixing hole portion 35a. The upper side portion in the protruding portion 34b is located on the upper side than the fixing hole portion 35a.

[0044] AsFigure 7 As shown in FIG. 6, the protrusions 34b are in contact with the inner surface of the fixing hole portion 35a. More specifically, the end portions of the portions of the protrusions 34b inside the fixing hole portion 35a on the second radial direction side are in contact with the inner surface of the fixing hole portion 35a. The protrusions 34b are provided at intervals in the circumferential direction around the center axis J. The plurality of protrusions 34b are arranged at equal intervals over one turn in the circumferential direction around the center axis J. In the first embodiment, the number of the plurality of protrusions 34b is four. In the first embodiment, the plurality of protrusions 34b are deformed in the second radial direction when the wafer support portion 34 is pressed into the fixing hole portion 35a. The plurality of protrusions 34b are, for example, in a state of being elastically deformed in the second radial direction inside the fixing hole portion 35a. As described above, the inclined portions 34c are provided at the end portions on the lower side of each of the protrusions 34b, and thus it is easy to insert the wafer support portion 34 into the fixing hole portion 35a when the wafer support portion 34 is pressed from the opening on the upper side of the fixing hole portion 35a.

[0045] In each of the plurality of wafer support portions 34, at least a portion of the outer peripheral surface of the portion of the wafer support portion 34 inside the fixing hole portion 35a is arranged apart from the inner surface of the fixing hole portion 35a. The outer peripheral surface of the portion of the wafer support portion 34 inside the fixing hole portion 35a includes the outer peripheral surface of the portion of the main body portion 34a inside the fixing hole portion 35a and the surface of the portion of the plurality of protrusions 34b inside the fixing hole portion 35a on the second radial direction side. In the first embodiment, the end portions of the plurality of protrusions 34b on the second radial direction side are in contact with the inner surface of the fixing hole portion 35a, and the other portions of the outer peripheral surface of the portion of the wafer support portion 34 inside the fixing hole portion 35a are arranged apart from the inner surface of the fixing hole portion 35a toward the second radial direction inner side. Thus, a gap S is provided between the outer peripheral surface of the wafer support portion 34 and the inner surface of the fixing hole portion 35a. In the first embodiment, the gap S is a void filled with gas.

[0046] Figure 8 FIG. 6 is a view of the state of the wafer W supported by the plurality of wafer support portions 34 viewed from the upper side, and is a view showing the arrangement relationship between the crystal orientation of the wafer W and the plurality of wafer support portions 34. In Figure 8 In FIG. 6, the crystal orientation of the wafer W represented by <11-20> is shown by single-dot chain arrows, respectively. As Figure 8 As shown in FIG. 6, the directions in which the rotation axes R are linked to the respective wafer support portions 34 when viewed in the vertical direction Z are different directions from the crystal orientation of the wafer W represented by <11-20>, respectively. That is, the directions in which the rotation axes R are linked to the respective wafer support portions 34 when viewed in the vertical direction Z are different directions from the cleavage direction of the wafer W, respectively. In Figure 8In the diagram, the direction connecting the rotation axis R to each wafer support 34, when viewed in the vertical direction Z, is represented by a dashed line passing through the rotation axis R and the central axis J of each wafer support 34. Preferably, the direction connecting the rotation axis R to each wafer support 34 deviates from the cleavage direction of the wafer W by 5° or more. More preferably, the direction connecting the rotation axis R to each wafer support 34 deviates from the cleavage direction of the wafer W by 10° or more. Even more preferably, the direction connecting the rotation axis R to each wafer support 34 deviates from the cleavage direction of the wafer W by 15° or more.

[0047] Furthermore, in this specification, "a direction that is different from other directions" means that a direction is not parallel to other directions. That is, "the direction in which the rotation axis R is connected to the wafer support 34 is different from the cleavage direction of the wafer W" means that the direction in which the rotation axis R is connected to the wafer support 34 is not parallel to the cleavage direction of the wafer W.

[0048] When viewed in the vertical direction Z, the direction connecting the rotation axis R to each wafer support 34 is different from the predetermined direction D indicated by the marking portion 36. When viewed in the vertical direction Z, the direction connecting the rotation axis R to each wafer support 34 is different from the direction inclined at 60° relative to the predetermined direction D. Figure 8 In the crystal orientation, the specified direction D is represented by [-12-10] and [1-210]. The direction tilted 60° relative to the specified direction D is represented by [-2110], [-1-120], [2-1-10], and [11-20].

[0049] When viewed in the vertical direction Z, the directions in which any two wafer support portions 34 are connected to each other are different from the crystal orientation of the wafer W, as indicated by <11-20>. That is, when viewed in the vertical direction Z, the directions in which any two wafer support portions 34 are connected to each other are different from the cleavage direction of the wafer W. Figure 8 In this diagram, the direction in which any two wafer support portions 34 are connected to each other, when viewed along the vertical direction Z, is represented by a dashed line passing through the central axis J of the two wafer support portions 34. Preferably, the direction in which any two wafer support portions 34 are connected to each other deviates from the cleavage direction of the wafer W by 5° or more. More preferably, the direction in which any two wafer support portions 34 are connected to each other deviates from the cleavage direction of the wafer W by 10° or more. Even more preferably, the direction in which any two wafer support portions 34 are connected to each other deviates from the cleavage direction of the wafer W by 15° or more.

[0050] Figure 9is a view of the state of the wafer W supported from the upper side by the plurality of wafer support portions 34, and is a view indicating the arrangement relationship between the measurement portion of the wafer W after film formation and the plurality of wafer support portions 34. Figure 9 The straight lines L1a, L1b shown are imaginary lines extending in a direction orthogonal to the vertical direction Z. The straight line L1a is a straight line passing through the rotation axis R when viewed in the vertical direction Z and extending in the prescribed direction D indicated by the marker portion 36. The straight line L1b is a straight line passing through the rotation axis R when viewed in the vertical direction Z and extending in a direction orthogonal to the prescribed direction D. The plurality of wafer support portions 34 are arranged at positions different from the straight line L1a passing through the rotation axis R and extending in the prescribed direction D when viewed in the vertical direction Z. The plurality of wafer support portions 34 are arranged at positions different from the straight line L1b passing through the rotation axis R and extending in a direction orthogonal to the prescribed direction D when viewed in the vertical direction Z. The plurality of wafer support portions 34 are preferably arranged, for example, 5 mm or more away from the straight lines L1a, L1b when viewed in the vertical direction Z, and more preferably 10 mm or more away.

[0051] Figure 9 The straight lines L2a, L2b shown are imaginary lines extending in a direction orthogonal to the vertical direction Z. The straight lines L2a, L2b are straight lines extending in a direction passing through the rotation axis R and inclined at 45° with respect to the prescribed direction D when viewed in the vertical direction Z. The direction in which the straight line L2a extends is orthogonal to the direction in which the straight line L2b extends. The plurality of wafer support portions 34 are arranged at positions different from the straight lines L2a, L2b passing through the rotation axis R and extending in a direction inclined at 45° with respect to the prescribed direction D when viewed in the vertical direction Z. The plurality of wafer support portions 34 are preferably arranged, for example, 5 mm or more away from the straight lines L2a, L2b when viewed in the vertical direction Z, and more preferably 10 mm or more away.

[0052] As Figure 8 shown in the first embodiment, the plurality of wafer support portions 34 include a pair of wafer support portions 34 sandwiching the rotation axis R when viewed in the vertical direction Z. The pair of wafer support portions 34 are arranged on the same straight line passing through the rotation axis R when viewed in the vertical direction Z. In the first embodiment, two pairs of the pair of wafer support portions 34 are provided.

[0053] As Figure 2 shown, the wafer guide portion 40 is supported by the base 30 from the lower side. The wafer guide portion 40 is ring-shaped so as to surround the rotation axis R. In more detail, as Figure 3As shown, the wafer guide portion 40 is annular, centered on the rotation axis R. The wafer guide portion 40 surrounds the outer edge of the wafer W. The wafer guide portion 40 is, for example, a plate with its surface facing the vertical direction Z. The wafer guide portion 40 is, for example, made of polycrystalline SiC. The wafer guide portion 40 can also be made of graphite. In this case, a SiC coating can be provided on the surface of the wafer guide portion 40.

[0054] like Figure 2 As shown, the wafer guide portion 40 is supported from below by the guide portion support portion 35. The lower surface of the wafer guide portion 40 contacts the radially outer portion of the upper surface of the guide portion support portion 35. The radially inner edge of the wafer guide portion 40 is located radially outer than the fixing hole portion 35a and the wafer support portion 34. The lower surface of the wafer guide portion 40 is located lower than the upper ends of the plurality of wafer support portions 34. The upper surface of the wafer guide portion 40 is located higher than the upper surface, i.e., surface Wa, of the wafer W mounted on the plurality of wafer support portions 34. The upper end of the radially inner side surface of the wafer guide portion 40 is located higher than the upper ends of the plurality of wafer support portions 34. That is, the upper end of the wafer support portion 34 is located lower than the upper end of the radially inner end of the wafer guide portion 40.

[0055] Furthermore, a recessed portion along the vertical direction Z can be formed on one side of the wafer guide portion 40 and the guide portion support portion 35, and a protruding portion along the vertical direction Z that fits into the recess can be provided on the other side of the wafer guide portion 40 and the guide portion support portion 35. With this structure, the radial deviation of the wafer guide portion 40 relative to the guide portion support portion 35 is suppressed.

[0056] like Figure 1 As shown, the drive unit 60 rotates the base 30 about a rotation axis R extending in the vertical direction Z. The drive unit 60 has a base holding part 61 and a power unit 62. The base holding part 61 is cylindrical with an opening at its upper side. The base 30 is held at the upper end of the base holding part 61. The base holding part 61 is located inside the chamber 20. The lower end of the base holding part 61 is located outside the chamber 20 via a hole formed in the bottom of the chamber 20. The power unit 62 rotates the base holding part 61 about the rotation axis R. The power unit 62 is, for example, an electric motor. The power unit 62 is connected to the lower end of the base holding part 61. Furthermore, the power unit 62 may have an electric motor and a reduction gear connected to the electric motor. In this case, the rotation of the electric motor is transmitted to the base holding part 61 via the reduction gear. The power unit 62 is located outside the chamber 20, for example.

[0057] The first heating section 51 and the second heating section 52 are heating sections capable of heating the susceptor 30. The susceptor 30 is heated by the first heating section 51 and the second heating section 52, whereby the wafer W and the wafer guide section 40 in contact with the susceptor 30 are heated. As shown in Figure 2 In the first embodiment, the first heating section 51 and the second heating section 52 are located on the lower side of the susceptor 30. The first heating section 51 and the second heating section 52 apply heat H from the lower side with respect to the susceptor 30, whereby the susceptor 30 is heated. The first heating section 51 and the second heating section 52 are located inside the susceptor holding section 61 in the drive section 60. The first heating section 51 and the second heating section 52 are resistive heating type heaters. The first heating section 51 and the second heating section 52 are, for example, composed of an electric heating wire extending along a plane orthogonal to the vertical direction Z. The first heating section 51 and the second heating section 52 can have any configuration as long as they are capable of heating an object.

[0058] The first heating section 51 is located on the radially outer side than the second heating section 52. The first heating section 51 surrounds the second heating section 52 from the radially outer side. The first heating section 51 is located on the lower side of the wafer support section 34 and the guide section support section 35. At least a portion of the first heating section 51 overlaps the wafer support section 34 when viewed in the vertical direction Z. In the first embodiment, a portion of the first heating section 51 on the radially inner side overlaps the wafer support section 34 when viewed in the vertical direction Z. A portion of the first heating section 51 on the radially outer side overlaps the wafer guide section 40 when viewed in the vertical direction Z.

[0059] The second heating section 52 is separated and located on the radially inner side of the first heating section 51. The second heating section 52 has a portion located on the lower side of the inner annular section 33 and a portion located on the lower side of the movable section 32. The radially outer edge portion of the second heating section 52 is located on the lower side of the inner annular section 33. A portion of the second heating section 52 on the radially inner side than the portion located on the lower side of the inner annular section 33 is located on the lower side of the movable section 32.

[0060] As shown in Figure 1 The third heating section 53 is annular and surrounds the supply pipe 24. In the first embodiment, the vapor phase growth apparatus 10 has three third heating sections 53. The three third heating sections 53 are arranged at intervals in the vertical direction Z. Each third heating section 53 heats the gas G passing through the inside of the supply pipe 24. Thereby, it is possible to increase the temperature of the gas G when it reaches the wafer W. Therefore, it is possible to increase the film formation speed of the SiC film formed on the surface of the wafer W. The number of third heating sections 53 provided in the vapor phase growth apparatus 10 can be two or less or four or more. The third heating section 53 is, for example, a resistive heating type heater composed of an electric heating wire. The third heating section 53 can have any configuration as long as it is capable of heating an object.

[0061] Figure 10 is a block diagram showing a part of the vapor deposition apparatus 10. As shown in Figure 10 , the vapor deposition apparatus 10 has a control section 90. The control section 90 controls each section of the vapor deposition apparatus 10. The control section 90 controls the first heating section 51, the second heating section 52, the third heating section 53, the drive section 60, the elevation section 80, and the transport section 100.

[0062] Figure 11 is a flowchart showing one example of the sequence of a film formation method using the vapor deposition apparatus 10 to form a film on the surface of the wafer W. As shown in Figure 11 , the control section 90 arranges the wafer W on the susceptor 30 (step S110). In step S110, the control section 90 transports the wafer W by the transport section 100, and loads the wafer W on the movable section 32 in the state of moving upward as shown in Figure 5 . The control section 90 controls the elevation section 80 to move the movable section 32 downward, and loads the wafer W on the movable section 32 on the plurality of wafer support sections 34. Thus, the wafer W is arranged on the susceptor 30.

[0063] In step S110, the control section 90 detects the orientation flat section Wd of the wafer W by the transport section 100, and loads the wafer W on the movable section 32 in such a manner that the direction in which the orientation flat section Wd extends is along the prescribed direction D indicated by the mark section 36 formed in the susceptor 30. That is, in the film formation method of the first embodiment, the film formation processing includes processing of making the orientation flat section Wd along the prescribed direction D. Thus, the plurality of wafer support sections 34 and the wafer W supported by the plurality of wafer support sections 34 become the arrangement relationship shown in Figure 3 , Figure 8 and Figure 9 . Therefore, when viewed in the vertical direction Z, the direction connecting the rotation axis R and each wafer support section 34 and the direction connecting any two wafer support sections 34 to each other become a direction different from the cleavage direction of the wafer W, that is, the crystal orientation of the wafer W indicated by <11-20>.

[0064] As shown in Figure 11After the wafer W is placed on the susceptor 30, the control section 90 performs film formation processing of forming a film on the surface of the wafer W (step S120). That is, the film formation method in the first embodiment includes the film formation processing of forming a film on the surface of the wafer W. The film formation processing is performed while the wafer W is supported by the plurality of wafer support sections 34 without changing the arrangement relationship at the time of the arrangement of the wafer W in step S110. That is, in the film formation method of the first embodiment, the film formation processing includes processing of supporting the wafer W by the plurality of wafer support sections 34 in such a manner that, when viewed in the vertical direction Z, the directions in which the rotation axis R is connected to each of the wafer support sections 34 become directions different from the cleavage direction of the wafer W. The film formation processing includes processing of supporting the wafer W by the plurality of wafer support sections 34 in such a manner that, when viewed in the vertical direction Z, the directions in which any two of the plurality of wafer support sections 34 are connected to each other become directions different from the cleavage direction of the wafer W. The film formation processing includes processing of supporting the wafer W by the plurality of wafer support sections 34 in such a manner that, when viewed in the vertical direction Z, the directions in which the rotation axis R is connected to each of the wafer support sections 34 become directions different from the crystal orientation of the wafer W represented by <11-20>. The film formation processing includes processing of supporting the wafer W by the wafer support sections 34 in such a manner that, when viewed in the vertical direction Z, the directions in which any two of the plurality of wafer support sections 34 are connected to each other become directions different from the crystal orientation of the wafer W represented by <11-20>.

[0065] In the film formation processing, the control section 90 rotates the wafer W around the rotation axis R (step S121), and heats the wafer W (step S122). In the film formation processing, the control section 90 rotates the susceptor 30 around the rotation axis R by the driving section 60, thereby rotating the wafer W around the rotation axis R. In the film formation processing, the control section 90 heats the susceptor 30 by the first heating section 51 and the second heating section 52, thereby heating the wafer W. The rotation of the wafer W and the heating of the wafer W are performed until the film formation processing ends.

[0066] In the film formation processing, the control section 90 controls the temperature of the wafer W (step S123). In step S123, the control section 90 measures the temperature of the wafer W by a temperature sensor not shown. In step S123, the control section 90 controls the first heating section 51 and the second heating section 52 on the basis of the measurement result of the temperature sensor not shown. The control section 90 controls the first heating section 51 and the second heating section 52 in such a manner that the temperature of the wafer W measured by the temperature sensor not shown becomes, for example, 1500°C or higher and 1650°C or lower.

[0067] In the film formation processing, the control section 90 causes the gas G including the raw material gas to flow into the chamber 20 from the supply port 21, and supplies the gas G to the wafer W (step S124). The surface Wa of the heated wafer W is supplied with the raw material gas, and thus a SiC film is formed on the surface Wa of the wafer W. The supply of the raw material gas to the wafer W is continued for a prescribed time, and thus a SiC film of a desired thickness is formed on the surface Wa of the wafer W. The wafer W is rotated around the rotation axis R by the drive section 60, and the surface Wa of the wafer W is supplied with the raw material gas, and thus the supply amount and fluctuation of the raw material gas in the surface of the surface Wa of the wafer W can be reduced. Therefore, the uniformity of the thickness of the film formed on the wafer W can be improved. In the film formation processing, the control section 90 heats the gas G in the supply pipe 24 by the third heating section 53. When the film formation processing is completed, the control section 90 stops the drive section 60 and each heating section, and stops the supply of the gas G into the chamber 20.

[0068] Further, the step S123 of controlling the temperature of the wafer W is continuously performed, for example, in the film formation processing. The step S123 can be performed every prescribed time. The step S121 of rotating the wafer W can be started after the wafer W is heated to a prescribed temperature and before the gas G is supplied.

[0069] After the film formation processing is completed, the control section 90 takes out the wafer W from the vapor deposition apparatus 10 (step S130). In the step S130, the control section 90 raises the movable section 32 by the lift section 80, and lifts the wafer W. The control section 90 transports the lifted wafer W by the transport section 100.

[0070] According to the first embodiment, the vapor deposition apparatus 10 used in the film formation method has the susceptor 30 that supports the wafer W. The susceptor 30 has a plurality of wafer support portions 34 that support the wafer W from the lower side and rotates around a rotation axis R that extends in the vertical direction Z. The plurality of wafer support portions 34 are arranged at intervals in the circumferential direction around the rotation axis R. In this way, since the plurality of wafer support portions 34 are arranged at intervals in the circumferential direction, the portions of the outer circumferential side of the wafer W that are between the wafer support portions 34 that are adjacent to each other at intervals in the circumferential direction are not in contact with the susceptor 30. Therefore, compared to the case where the wafer support portions 34 are annular, the number of portions of the outer circumferential side of the wafer W that are not in contact with the susceptor 30 can be increased, and the temperature increase of the wafer W at the portions can be suppressed. Thus, the film thickness and the carrier concentration of the film formed in the portion of the outer circumferential side of the wafer W can be suppressed from greatly differing from the film thickness and the carrier concentration of the film formed in the portion of the central side of the wafer W, and the wafer surface distribution of the film formed in the portion of the outer circumferential side of the wafer W can be suppressed from deteriorating. Therefore, in the wafer W after film formation, the portion that cannot be used as a region for forming a semiconductor element can be reduced. Thus, the yield of the semiconductor device manufactured using the wafer W can be suppressed from decreasing.

[0071] According to the first embodiment, when viewed in the vertical direction Z, the directions in which the rotation axis R and each wafer support portion 34 are connected are directions different from the cleavage direction of the wafer W. In other words, in the film formation method of forming a film on the surface of the wafer W using the vapor deposition apparatus 10, the film formation process includes a process of supporting the wafer W by the plurality of wafer support portions 34 in such a manner that, when viewed in the vertical direction Z, the directions in which the rotation axis R and each wafer support portion 34 are connected become directions different from the cleavage direction of the wafer W. Therefore, the directions in which the thermal stress generated in the wafer W by the heat transmitted from each wafer support portion 34 acts can be deviated from the cleavage direction in which the wafer W is likely to break. Thus, in the film formation process, the wafer W supported by the plurality of wafer support portions 34 can be suppressed from breaking, or the generation of crystal defects, i.e., dislocations, in the wafer W by the thermal stress can be suppressed. The effect of suppressing the wafer W from breaking is preferably obtained in a case where, when viewed in the vertical direction Z, the directions in which the rotation axis R and each wafer support portion 34 are connected are deviated from the cleavage direction of the wafer W by an angle of 5° or more, more preferably by an angle of 10° or more, and further more preferably by an angle of 15° or more. In addition, the effect of suppressing the wafer W from breaking can be obtained if, when viewed in the vertical direction Z, the directions in which the rotation axis R and each wafer support portion 34 are connected are deviated from the cleavage direction of the wafer W by an angle greater than 0°.

[0072] According to the first embodiment, the directions in which any two of the plurality of wafer support portions 34 are linked to each other when viewed in the vertical direction Z are respectively different from the cleavage direction of the wafer W. In other words, the film formation process includes a process of supporting the wafer W by the plurality of wafer support portions 34 in such a manner that the directions in which any two of the plurality of wafer support portions 34 are linked to each other when viewed in the vertical direction Z are respectively different from the cleavage direction of the wafer W. Thus, even if thermal stress generated due to heat transmitted from the two wafer support portions 34 to the wafer W is generated in the directions in which the two wafer support portions 34 are linked to each other, the directions can be set to be different from the cleavage direction in which the wafer W is easily broken. Thus, the wafer W can be further prevented from being broken during the film formation process. The effect of preventing the wafer W from being broken is preferably obtained in a case where the angle by which the directions in which any two of the wafer support portions 34 are linked to each other when viewed in the vertical direction Z are deviated from the cleavage direction of the wafer W is 5° or more, more preferably in a case where the angle is 10° or more, and further preferably in a case where the angle is 15° or more. In addition, the effect of preventing the wafer W from being broken can be obtained if the angle by which the directions in which any two of the wafer support portions 34 are linked to each other when viewed in the vertical direction Z are deviated from the cleavage direction of the wafer W is greater than 0°.

[0073] According to the first embodiment, the wafer W is formed of a single crystal having a crystal structure of hexagonal system. The directions in which the rotation axis R is linked to each of the wafer support portions 34 when viewed in the vertical direction Z are respectively different from the crystal orientation of the wafer W represented by <11-20>. In other words, the film formation process includes a process of supporting the wafer W by the plurality of wafer support portions 34 in such a manner that the directions in which the rotation axis R is linked to each of the wafer support portions 34 when viewed in the vertical direction Z are respectively different from the crystal orientation of the wafer W represented by <11-20>. Thus, the directions in which thermal stress generated in the wafer W by heat transmitted from each of the wafer support portions 34 acts can be made different from the cleavage direction of the wafer W formed of a single crystal having a crystal structure of hexagonal system. Thus, the wafer W formed of a single crystal having a crystal structure of hexagonal system can be prevented from being broken.

[0074] According to the first embodiment, the directions in which any two of the plurality of wafer support portions 34 are linked to each other when viewed in the vertical direction Z are directions different from the crystal orientation of the wafer W represented by <11-20>. In other words, the film formation process includes supporting the wafer W by the wafer support portions 34 in such a manner that the directions in which any two of the plurality of wafer support portions 34 are linked to each other when viewed in the vertical direction Z become directions different from the crystal orientation of the wafer W represented by <11-20>. Thus, it is possible to further suppress breakage of the wafer W formed of a single crystal having a crystal structure of a hexagonal system.

[0075] According to the first embodiment, the base 30 has a marker portion 36 representing a prescribed direction D orthogonal to the vertical direction Z. The directions in which the rotation axis R is linked to each of the wafer support portions 34 when viewed in the vertical direction Z are directions different from the prescribed direction D and also different from directions inclined by 60° with respect to the prescribed direction D. The wafer W is a SiC substrate. The plate surface of the wafer W is a surface along a crystal plane represented by (0001). A directional planar portion Wd extending in the crystal orientation of the wafer W represented by <11-20> is provided at the outer edge of the wafer W. The film formation process includes causing the directional planar portion Wd to be along the prescribed direction D. Thus, as shown in FIG. 6, the cleavage direction of the wafer W becomes a direction inclined by 60° with respect to the direction in which the directional planar portion Wd extends and the direction in which the directional planar portion Wd extends. Thus, by arranging each of the wafer support portions 34 in such a manner that the direction in which the rotation axis R is linked to each of the wafer support portions 34 when viewed in the vertical direction Z is different from both the prescribed direction D represented by the marker portion 36 and the direction inclined by 60° with respect to the prescribed direction D, and by supporting the wafer W by the plurality of wafer support portions 34 with the directional planar portion Wd coinciding with the prescribed direction D, it is possible to set the direction in which the rotation axis R is linked to each of the wafer support portions 34 when viewed in the vertical direction Z to be different from the cleavage direction of the wafer W having a crystal structure of a hexagonal system. Thus, it is possible to suppress breakage of the wafer W formed of a single crystal having a crystal structure of a hexagonal system in the film formation process. Figure 8

[0076] For example, when measuring the thickness and carrier concentration of a film formed on the surface of the wafer W for the purpose of confirming the quality of the wafer W, the thickness and carrier concentration of the film are measured at a plurality of positions on a straight line extending in a direction orthogonal to the plate thickness direction of the wafer W passing through the center Cw of the substantially circular plate-shaped wafer W. The direction in which the measurement is performed is determined, for example, on the basis of the direction in which a plurality of semiconductor elements formed on the wafer W are arranged. As shown in FIG. 7, the thickness and carrier concentration of the film are measured at a plurality of positions on a straight line extending in a direction orthogonal to the plate thickness direction of the wafer W passing through the center Cw of the wafer W. Figure 9 ​In the wafer W provided with the orientation flat portion Wd, semiconductor elements are formed in a plurality of element formation regions We arranged in a matrix in a direction in which the orientation flat portion Wd extends and in a direction orthogonal to the direction in which the orientation flat portion Wd extends. Thus, the measurement of the film is performed in a portion of the wafer W that is located on a measurement line ML1a, ML1b that extends in the two directions in which the plurality of element formation regions We are arranged, respectively. The measurement line ML1a is a straight line that passes through the center Cw of the wafer W and extends in the direction in which the orientation flat portion Wd extends, as viewed in the thickness direction of the wafer W. The measurement line ML1b is a straight line that passes through the center Cw of the wafer W and extends in the direction orthogonal to the direction in which the orientation flat portion Wd extends, as viewed in the thickness direction of the wafer W. In the film formation process, the portion of the wafer W that is supported by the plurality of wafer support portions 34 is likely to be higher in temperature than the other portions of the wafer W. Thus, the film thickness and the carrier concentration in the portion of the wafer W that is supported by the plurality of wafer support portions 34 are likely to deviate from the average values. Thus, the portion of the wafer W that is supported by the plurality of wafer support portions 34 is sometimes not used for the manufacture of semiconductor devices. It is sometimes not preferable to perform the measurement of the film with respect to the portion of the wafer W that is not used for the manufacture of semiconductor devices as described above.

[0077] In view of the above, according to the first embodiment, the plurality of wafer support portions 34 are arranged at positions different from a straight line L1a that passes through the rotation axis R and extends in the prescribed direction D, and at positions different from a straight line L1b that passes through the rotation axis R and extends in a direction orthogonal to the prescribed direction D, as viewed in the vertical direction Z. The wafer W is arranged on the plurality of wafer support portions 34 with the center Cw of the wafer W coinciding with the rotation axis R and with the direction in which the orientation flat portion Wd extends coinciding with the prescribed direction D, whereby the straight lines L1a, L1b coincide with the measurement lines ML1a, ML1b at which the film of the wafer W is measured, respectively, as viewed in the vertical direction Z. That is, the straight line L1a coincides with the measurement line ML1a that passes through the center Cw of the wafer W and extends in the direction in which the orientation flat portion Wd extends, as viewed in the vertical direction Z. The straight line L1b coincides with the measurement line ML1b that passes through the center Cw of the wafer W and extends in the direction orthogonal to the direction in which the orientation flat portion Wd extends, as viewed in the vertical direction Z. The plurality of wafer support portions 34 are arranged at positions different from the straight lines L1a, L1b, as viewed in the vertical direction Z, and thus, in the film formation process, the portion of the wafer W that is different from the measurement portion on the measurement lines ML1a, ML1b at which the measurement is performed after the film formation is supported by the plurality of wafer support portions 34. Thus, the measurement of the film thickness and the carrier concentration in the portion of the wafer W that is supported by the plurality of wafer support portions 34 in the film formation process is suppressed.

[0078] When measuring the thickness and carrier concentration of the film formed on the surface of the wafer W, the measurement of the film formed on the wafer W is sometimes performed, for example, in a direction inclined at 45° with respect to two directions in which the plurality of element formation regions We are arranged. In this case, as shown in FIG. 2, the measurement of the film formed on the wafer W is performed on measurement lines ML2a, ML2b extending through the center Cw of the wafer W in directions inclined at 45° with respect to the direction in which the orientation flat portion Wd extends, when viewed in the plate thickness direction of the wafer W. The directions in which the measurement lines ML2a extend and the directions in which the measurement lines ML2b extend are orthogonal to each other. Figure 9

[0079] In view of the above, according to the first embodiment, the plurality of wafer support portions 34 are arranged at positions different from straight lines L2a, L2b extending through the rotation axis R in directions inclined at 45° with respect to the prescribed direction D, when viewed in the vertical direction Z. The wafer W is arranged on the plurality of wafer support portions 34 with the center Cw of the wafer W coinciding with the rotation axis R and with the direction in which the orientation flat portion Wd extends coinciding with the prescribed direction D, whereby the straight lines L2a, L2b coincide with the measurement lines ML2a, ML2b at which the film of the wafer W is measured, respectively, when viewed in the vertical direction Z. Therefore, even in the case where the film of the wafer W is measured along the measurement lines ML2a, ML2b, the film thickness and the carrier concentration of the portion of the wafer W supported by the plurality of wafer support portions 34 during the film formation process are suppressed from being measured.

[0080] Further, as to the effect that the film thickness and the carrier concentration of the portion of the wafer W supported by the plurality of wafer support portions 34 during the film formation process are suppressed from being measured, when viewed in the vertical direction Z, the effect is preferably obtained in the case where the plurality of wafer support portions 34 are arranged at positions separated from the straight lines L1a, L1b, L2a, L2b by 5 mm or more, and more preferably in the case where the plurality of wafer support portions 34 are arranged at positions separated from the straight lines L1a, L1b, L2a, L2b by 10 mm or more.

[0081] According to the first embodiment, the plurality of wafer support portions 34 include a pair of wafer support portions 34 sandwiching the rotation axis R, when viewed in the vertical direction Z. Therefore, the wafer W is stably supported by the plurality of wafer support portions 34.

[0082] According to the first embodiment, the number of the plurality of wafer support portions 34 is four or more. Therefore, the wafer W is stably supported by the plurality of wafer support portions 34, as compared with the case where the number of the wafer support portions 34 is three or less. In addition, since the number of the wafer support portions 34 is four or more, the force received by each wafer support portion 34 from the wafer W can be reduced, as compared with the case where the number of the wafer support portions 34 is three or less. Thus, the plurality of wafer support portions 34 can be suppressed from being worn by the contact with the wafer W. ​

[0083] According to the first embodiment, the base 30 has the base portion 31 independent of the plurality of wafer support portions 34. The base portion 31 has a plurality of fixing hole portions 35a which are arranged at intervals in the circumferential direction and which are open upward. The plurality of wafer support portions 34 are respectively fixed inside the plurality of fixing hole portions 35a and respectively protrude upward from the inside of the plurality of fixing hole portions 35a. Thus, compared with the case where the base portion 31 and the plurality of wafer support portions 34 are integrally formed, heat is less likely to be transmitted from the base portion 31 to each wafer support portion 34. Thus, it is possible to suppress an increase in temperature of the portion of the wafer W in the outer peripheral side which is in contact with each wafer support portion 34. Thus, it is possible to suppress an increase in temperature of the outer peripheral side portion of the wafer W in the film formation process compared with the central portion of the wafer W. Thus, it is further possible to suppress a large difference in film thickness and carrier concentration of the film formed in the portion of the wafer W in the outer peripheral side and the film formed in the portion of the wafer W in the central side. Thus, it is further possible to suppress a deterioration in wafer surface distribution of the film formed in the portion of the wafer W in the outer peripheral side. Thus, in the wafer W after film formation, it is possible to further reduce the portion which cannot be used as a region for forming a semiconductor element. Thus, it is possible to further suppress a reduction in yield of a semiconductor device manufactured using the wafer W.

[0084] According to the first embodiment, in each of the plurality of wafer support portions 34, at least a portion of the outer peripheral surface of the portion of the wafer support portion 34 inside the fixing hole portion 35a is arranged apart from the inner surface of the fixing hole portion 35a. Thus, compared with the case where the outer peripheral surface of each wafer support portion 34 is in contact with the inner surface of each fixing hole portion 35a throughout the entirety, heat is more unlikely to be transmitted from the base portion 31 to each wafer support portion 34. Thus, it is possible to further suppress an increase in temperature of the portion of the wafer W in contact with the plurality of wafer support portions 34.

[0085] According to the first embodiment, the plurality of wafer support portions 34 respectively have a main body portion 34a extending in the vertical direction Z and a protruding portion 34b provided to the outer peripheral surface of the main body portion 34a. The protruding portion 34b is in contact with the inner surface of the fixing hole portion 35a. Thus, it is possible to fix the wafer support portion 34 inside the fixing hole portion 35a via the protruding portion 34b and to separate a portion of the outer peripheral surface of the wafer support portion 34 from the inner surface of the fixing hole portion 35a.

[0086] Further, a scratch remains in the portion of the back surface Wb of the wafer W which is in contact with the plurality of wafer support portions 34. Thus, by confirming the scratch in the back surface Wb of the wafer W after film formation, it is possible to confirm the relationship between the portion which supports the wafer W in the film formation process and the cleavage direction of the wafer W and the relationship between the portion which supports the wafer W in the film formation process and the measurement portion of the film of the wafer W.

[0087] In addition, the number of the plurality of wafer support portions 34 is two or more, and is not limited to four. The number of the plurality of wafer support portions 34 can be six as shown in the wafer support portions 134. Figure 12 Figure 12 is a view that shows the plurality of wafer support portions 134 in the modification example of the first embodiment. Regarding the six wafer support portions 134 shown in Figure 12 , the arrangement relationship of the cleavage direction of the wafer W and the prescribed direction D and the like is the same as that of the wafer support portions 34 described above.

[0088] Hereinafter, embodiments different from the above-described embodiments will be described. In the description of each of the following embodiments, regarding the structure that is the same as the structure described in the structure described in the upper layer than the description of each of the embodiments, sometimes the description is omitted by appropriately adding the same reference numerals and the like. In addition, regarding the portion corresponding to each part of the structure described in the upper layer than the description of each of the embodiments, the same name is marked, and a different reference numeral is marked, and the point different from the above-described structure is described, and regarding the same point as the above-described structure, sometimes the description is omitted. Furthermore, as the structure whose description is omitted in each of the following embodiments, the same structure as the structure described in the upper layer than each of the embodiments can be employed within a range where no contradiction occurs.

[0089] (Second Embodiment)

[0090] Figure 13 is a view that shows the pedestal 230 in the second embodiment as viewed from the upper side. Furthermore, in Figure 13 , the outline of the wafer W is shown by a double-dotted line. As shown in Figure 13 , the pedestal 230 has five wafer support portions 234. The five wafer support portions 234 include three wafer support portions 234a, one wafer support portion 234b, and one wafer support portion 234c. The four wafer support portions 234 of the three wafer support portions 234a and the one wafer support portion 234b are arranged in the same manner as the four wafer support portions 34 in the first embodiment.

[0091] The wafer support portion 234b is arranged at the same position as the wafer support portion 34 in the four wafer support portions 34 in the first embodiment that supports the portion of the radial outer edge portion of the wafer W located on the radially inner side of the orientation flat portion Wd. The wafer support portion 234c is arranged at a position adjacent to the wafer support portion 234b in the circumferential direction. The wafer support portion 234c supports the portion of the radial outer edge portion of the wafer W located on the radially inner side of the orientation flat portion Wd.

[0092] ​In the second embodiment, the wafer support portions 234b and 234c form a marker portion 236. A direction in which the wafer support portion 234b is connected to the wafer support portion 234c when viewed in the vertical direction Z is a prescribed direction D. That is, in the second embodiment, the marker portion 236 indicates the prescribed direction D in which the orientation flat portion Wd provided at the outer edge of the wafer W is made to face when the wafer W is supported by the plurality of wafer support portions 234, by the direction in which the two wafer support portions 234b and 234c are arranged. In Figure 13 In the second embodiment, the wafer support portion 234b and 234c form a marker portion 236. A direction in which the wafer support portion 234b is connected to the wafer support portion 234c when viewed in the vertical direction Z is a prescribed direction D. That is, in the second embodiment, the marker portion 236 indicates the prescribed direction D in which the orientation flat portion Wd provided at the outer edge of the wafer W is made to face when the wafer W is supported by the plurality of wafer support portions 234, by the direction in which the two wafer support portions 234b and 234c are arranged. In

[0093] The base portion 231 is the same as the base portion 31 in the first embodiment except that a fixing hole portion for fixing the wafer support portion 234c is provided. The other structures of the base 230 are the same as the other structures of the base 30 in the first embodiment.

[0094] (Third Embodiment)

[0095] Figure 14 is a view of the base 330 in the third embodiment as viewed from the upper side. In Figure 14 , the outer shape of the wafer W is indicated by a double-dotted line. As Figure 14 indicated, the base 330 has four wafer support portions 334. The four wafer support portions 334 are arranged similarly to the four wafer support portions 34 in the first embodiment. The four wafer support portions 334 include three wafer support portions 334c and one wafer support portion 334d. The three wafer support portions 334c are shaped the same as the wafer support portions 34 in the first embodiment.

[0096] When viewed in the vertical direction Z, the shape of the one wafer support portion 334d is different from the shape of the three wafer support portions 334c. The wafer support portion 334d has a main body portion 334a and a plurality of convex portions 334b. The main body portion 334a of the wafer support portion 334d is a quadrilateral shape when viewed in the vertical direction Z. In the third embodiment, the wafer support portion 334d is a marker portion that indicates the prescribed direction D. In Figure 14In the fourth embodiment, the edge of the main body portion 334a in the wafer support portion 334d that extends in the left-right direction when viewed in the vertical direction Z indicates the prescribed direction D. For example, the control portion 90 configures the wafer W in such a manner that the orientation flat portion Wd is closest to the wafer support portion 334d that is the marker portion among the four wafer support portions 334 and the orientation flat portion Wd is along one edge of the wafer support portion 334d, whereby the orientation flat portion Wd can be configured in the prescribed direction D. The plurality of convex portions 334b are the same as the plurality of convex portions 34b in the first embodiment except that each of the plurality of convex portions 334b is provided on each edge of the main body portion 334a that is a quadrangular shape when viewed in the vertical direction Z.

[0097] The base portion 331 is the same as the base portion 31 in the first embodiment except that the shape of the fixing hole portion 335a that fixes the wafer support portion 334d is a quadrangular shape when viewed in the vertical direction Z. The other structure of the pedestal 330 is the same as the other structure of the pedestal 30 in the first embodiment. Further, in the third embodiment, the fixing hole portion 335a that fixes the wafer support portion 334c can also be the marker portion. In this case, the edge of the fixing hole portion 335a that is a quadrangular shape when viewed in the vertical direction Z indicates the prescribed direction D.

[0098] According to at least one embodiment described above, a film formation method is a film formation method of forming a film on a surface of a wafer using a vapor deposition apparatus. The film formation method of the embodiment includes a film formation process of forming a film on a surface of a wafer. The vapor deposition apparatus has a pedestal that supports the wafer. The pedestal has a plurality of wafer support portions that support the wafer from a lower side and rotates around a rotation axis that extends in a vertical direction. The plurality of wafer support portions are arranged at intervals in a circumferential direction around the rotation axis. The film formation process includes a process of supporting the wafer by the plurality of wafer support portions in such a manner that, when viewed in the vertical direction, a direction in which the rotation axis is connected to each wafer support portion becomes a direction different from a cleavage direction of the wafer. Thereby, as described above, it is possible to suppress a decrease in yield of a semiconductor device manufactured using the wafer. In addition, it is possible to suppress a breakage of the wafer in the film formation process.

[0099] If at least a part of the outer peripheral surface of the portion of the wafer support portion that is located inside the fixing hole portion is arranged separately from the inner surface of the fixing hole portion, the plurality of wafer support portions can be fixed inside the plurality of fixing hole portions in any manner, respectively.

[0100] Further, the entire outer circumferential surface of the portion of the wafer support section inside the fixing hole section can be in contact with the inner surface of the fixing hole section. The wafer support section can be independent of the base section, or can be integrally formed with the base section. In these cases, by arranging a plurality of wafer support sections at intervals in the circumferential direction, as described above, it is also possible to suppress a decrease in yield of semiconductor devices manufactured using the wafer. Further, when viewed in the vertical direction, the directions in which the rotational axis is linked to each wafer support section are respectively directions different from the cleaving direction of the wafer, whereby it is possible to suppress breakage of the wafer during film formation processing, and thus it is possible to further suppress a decrease in yield of semiconductor devices manufactured using the wafer.

[0101] The material that constitutes the plurality of wafer support sections can be different from the material that constitutes the base section of the susceptor. In this case, the thermal conductivity of the plurality of wafer support sections can be lower than the thermal conductivity of the base section of the susceptor. In this case, it is possible to further suppress the transfer of heat from the base section of the susceptor to the plurality of wafer support sections. Thereby, it is possible to further suppress an increase in temperature of the portion of the wafer that is in contact with the plurality of wafer support sections. In the case where the thermal conductivity of the plurality of wafer support sections is lower than the thermal conductivity of the base section of the susceptor, as the material that constitutes the plurality of wafer support sections, for example, graphite, SiC, SiN, or the like can be employed.

[0102] As long as the direction in which the rotational axis is linked to each wafer support section when viewed in the vertical direction is a direction in which a straight line that passes through the rotational axis and each wafer support section extends when viewed in the vertical direction. As long as the direction in which the two wafer support sections are linked to each other when viewed in the vertical direction is a direction in which a straight line that passes through the two wafer support sections extends when viewed in the vertical direction. As long as the mark section indicates a prescribed direction along which the orientation plane section is to be oriented, it can be any shape, and can be formed at any position of the susceptor. The mark section can also not be formed on the susceptor.

[0103] The film formation method, the susceptor, and the vapor phase growth apparatus of the embodiment include the following note.

[0104] (Note 1)

[0105] A film formation method of forming a film on a surface of a wafer using a vapor phase growth apparatus,

[0106] The film formation method includes film formation processing of forming a film on the surface of the wafer,

[0107] The vapor phase growth apparatus has a susceptor that supports the wafer,

[0108] The susceptor has a plurality of wafer support sections that support the wafer from the lower side, and the susceptor rotates around a rotational axis that extends in the vertical direction,

[0109] The plurality of wafer support sections are arranged at intervals in the circumferential direction around the rotational axis,

[0110] The film formation treatment includes a process of supporting the wafers by the plurality of wafer support portions so that directions connecting the rotation axis and each of the wafer support portions are different from a cleavage direction of the wafer when viewed in a vertical direction.

[0111] (Note 2)

[0112] The film formation method according to Note 1, in which

[0113] The film formation treatment includes a process of supporting the wafers by the plurality of wafer support portions so that directions connecting any two of the plurality of wafer support portions are different from a cleavage direction of the wafer when viewed in a vertical direction.

[0114] (Note 3)

[0115] The film formation method according to Note 1 or 2, in which

[0116] The wafer is formed of a single crystal having a crystal structure of hexagonal system,

[0117] The film formation treatment includes a process of supporting the wafers by the plurality of wafer support portions so that directions connecting the rotation axis and each of the wafer support portions are different from a crystal orientation of the wafer represented by <11-20> when viewed in a vertical direction.

[0118] (Note 4)

[0119] The film formation method according to Note 3, in which

[0120] The film formation treatment includes a process of supporting the wafers by the plurality of wafer support portions so that directions connecting any two of the plurality of wafer support portions are different from a crystal orientation of the wafer represented by <11-20> when viewed in a vertical direction.

[0121] (Note 5)

[0122] The film formation method according to Note 3 or 4, in which

[0123] The susceptor has a marker portion representing a prescribed direction orthogonal to a vertical direction,

[0124] The direction connecting the rotation axis and each of the wafer support portions is a direction different from the prescribed direction and is also a direction different from a direction inclined by 60° with respect to the prescribed direction when viewed in a vertical direction,

[0125] the wafer is a SiC substrate,

[0126] a plate surface of the wafer is along a plane of a crystal plane represented by (0001),

[0127] an orientation flat portion extending in a crystal orientation of the wafer represented by <11-20> is provided at an outer edge of the wafer,

[0128] the film formation process includes a process of causing the orientation flat portion to be oriented in the prescribed direction.

[0129] (Paragraph 6)

[0130] the film formation method according to any one of Paragraphs 5 to 6, wherein

[0131] when viewed in the vertical direction, the plurality of wafer support portions are disposed at positions different from a position on a straight line extending in the prescribed direction passing through the rotation axis, and are disposed at positions different from a position on a straight line extending in a direction orthogonal to the prescribed direction passing through the rotation axis.

[0132] (Paragraph 7)

[0133] the film formation method according to any one of Paragraphs 5 to 6, wherein

[0134] when viewed in the vertical direction, the plurality of wafer support portions are disposed at positions different from a position on a straight line extending in a direction inclined by 45° with respect to the prescribed direction passing through the rotation axis.

[0135] (Paragraph 8)

[0136] the film formation method according to any one of Paragraphs 1 to 7, wherein

[0137] the plurality of wafer support portions include a pair of wafer support portions sandwiching the rotation axis when viewed in the vertical direction.

[0138] (Paragraph 9)

[0139] the film formation method according to any one of Paragraphs 1 to 8, wherein

[0140] the number of the plurality of wafer support portions is four or more.

[0141] (Paragraph 10)

[0142] a susceptor configured to support a wafer and to rotate about a rotation axis extending in a vertical direction,

[0143] the susceptor has:

[0144] a plurality of wafer support portions that support the wafer from a lower side; and

[0145] a marker portion that indicates a prescribed direction orthogonal to a vertical direction,

[0146] the plurality of wafer support portions are arranged at intervals in a circumferential direction around the rotation axis,

[0147] when viewed in the vertical direction, the direction in which the rotation axis is linked to each of the wafer support portions is a direction different from the prescribed direction and is also a direction different from a direction inclined by 60° with respect to the prescribed direction.

[0148] (Paragraph 11)

[0149] the pedestal as described in Paragraph 10, wherein

[0150] when viewed in the vertical direction, the plurality of wafer support portions are arranged at positions different from positions on a straight line extending in the prescribed direction that passes through the rotation axis and are also arranged at positions different from positions on a straight line extending in a direction orthogonal to the prescribed direction that passes through the rotation axis.

[0151] (Paragraph 12)

[0152] the pedestal as described in Paragraph 10 or 11, wherein

[0153] when viewed in the vertical direction, the plurality of wafer support portions are arranged at positions different from positions on a straight line extending in a direction inclined by 45° with respect to the prescribed direction that passes through the rotation axis.

[0154] (Paragraph 13)

[0155] the pedestal as described in any one of Paragraphs 10 to 12, wherein

[0156] the plurality of wafer support portions include a pair of wafer support portions that sandwich the rotation axis when viewed in the vertical direction.

[0157] (Paragraph 14)

[0158] the pedestal as described in any one of Paragraphs 10 to 13, wherein

[0159] the number of the plurality of wafer support portions is four or more.

[0160] (Paragraph 15)

[0161] the pedestal as described in any one of Paragraphs 10 to 14, wherein

[0162] has a base portion independent of the plurality of wafer support portions,

[0163] The base has a plurality of fixing hole portions which are open upward and arranged at intervals in the circumferential direction,

[0164] The plurality of wafer support portions are respectively fixed inside the plurality of fixing hole portions and respectively protrude upward from inside the plurality of fixing hole portions.

[0165] (Paragraph 16)

[0166] The base according to Paragraph 15, wherein

[0167] In each of the plurality of wafer support portions, at least a portion of an outer circumferential surface of a portion of the wafer support portion inside the fixing hole portion is arranged apart from an inner surface of the fixing hole portion.

[0168] (Paragraph 17)

[0169] The base according to Paragraph 16, wherein

[0170] The plurality of wafer support portions each have:

[0171] a main body portion which extends in a vertical direction; and

[0172] a convex portion which is provided to an outer circumferential surface of the main body portion,

[0173] The convex portion is in contact with an inner surface of the fixing hole portion.

[0174] (Paragraph 18)

[0175] The base according to any one of Paragraphs 15 to 17, wherein

[0176] Thermal conductivities of the plurality of wafer support portions are lower than a thermal conductivity of the base.

[0177] (Paragraph 19)

[0178] A vapor phase growth apparatus, wherein there are:

[0179] The base according to any one of Paragraphs 10 to 18;

[0180] a drive portion which rotates the base around the rotation axis; and

[0181] a heating portion which is capable of heating the base.

[0182] Several embodiments of the present invention have been described, but these embodiments are given by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are equally included within the scope of the invention as set forth in the claims and its equivalents.

[0183] Explanation of reference numerals in the attached figures

[0184] 10…Vacuum phase growth apparatus, 30, 230, 330…Base, 31, 231, 331…Base, 34, 134, 234, 234a, 234b, 234c, 334, 334a…Wafer support, 34a…Main body, 34b, 334b…Protrusion, 35a, 335a…Fixing hole, 36, 236…Marking part, 51…First heating part (heating part), 52…Second heating part (heating part), 60…Drive part, 334b…Wafer support part (marking part), D…Specified direction, L1a, L2a, L1b, L2b…Line, R…Rotation axis, W…Wafer, Wd…Orientation plane, Z…Vertical direction.

Claims

1. A film forming method of forming a film on a surface of a wafer using a vapor deposition apparatus, the film forming method including a film forming process of forming a film on the surface of the wafer, the vapor deposition apparatus having a susceptor that supports the wafer, the susceptor having a plurality of wafer supporting portions that support the wafer from a lower side, and the susceptor being rotated around a rotation axis that extends in a vertical direction, the plurality of wafer supporting portions being arranged at intervals in a circumferential direction around the rotation axis, the film forming process including a process of supporting the wafer by the plurality of wafer supporting portions so that, when viewed in the vertical direction, directions in which the rotation axis and each of the wafer supporting portions are connected become directions different from a cleavage direction of the wafer, respectively.

2. The film forming method according to claim 1, wherein the film forming process includes a process of supporting the wafer by the plurality of wafer supporting portions so that, when viewed in the vertical direction, directions in which any two of the plurality of wafer supporting portions are connected to each other become directions different from the cleavage direction of the wafer, respectively.

3. The film forming method according to claim 1, wherein the wafer is formed of a single crystal having a crystal structure of a hexagonal system, the film forming process includes a process of supporting the wafer by the plurality of wafer supporting portions so that, when viewed in the vertical direction, directions in which the rotation axis and each of the wafer supporting portions are connected become directions different from a crystal orientation of the wafer represented by <11-20>, respectively.

4. The film forming method according to claim 3, wherein the film forming process includes a process of supporting the wafer by the wafer supporting portions so that, when viewed in the vertical direction, directions in which any two of the plurality of wafer supporting portions are connected to each other become directions different from the crystal orientation of the wafer represented by <11-20>, respectively.

5. The film forming method according to claim 3, wherein the susceptor has a marker portion that represents a prescribed direction orthogonal to the vertical direction, the direction in which the rotation axis and each of the wafer supporting portions are connected is a direction different from the prescribed direction and is also a direction different from a direction inclined by 60° with respect to the prescribed direction, when viewed in the vertical direction, the wafer is a SiC substrate, a plate surface of the wafer is a surface along a crystal plane represented by (0001), an orientation flat portion extending in the crystal orientation of the wafer represented by <11-20> is provided at an outer edge of the wafer, the film forming process includes a process of causing the orientation flat portion to follow the prescribed direction.

6. The film forming method according to claim 5, wherein the plurality of wafer supporting portions are arranged at positions different from a position on a straight line extending in the prescribed direction through the rotation axis and are also arranged at positions different from a position on a straight line extending in a direction orthogonal to the prescribed direction through the rotation axis, when viewed in the vertical direction.

7. The film forming method according to claim 5, wherein The plurality of wafer support portions are arranged at positions different from a position on a straight line extending in the prescribed direction passing through the rotation axis when viewed in the vertical direction.

8. The film forming method according to claim 1, wherein The plurality of wafer support portions include a pair of wafer support portions sandwiching the rotation axis when viewed in the vertical direction.

9. The film forming method according to claim 1, wherein The number of the plurality of wafer support portions is four or more.

10. A susceptor provided in a vapor phase growth apparatus, supporting a wafer, and rotating around a rotation axis extending in a vertical direction, The susceptor has: a plurality of wafer support portions supporting the wafer from a lower side; and a marker portion indicating a prescribed direction orthogonal to the vertical direction, The plurality of wafer support portions are arranged at intervals in a circumferential direction around the rotation axis, When viewed in the vertical direction, a direction connecting the rotation axis and each of the wafer support portions is a direction different from the prescribed direction and is also a direction different from a direction inclined by 60° with respect to the prescribed direction.

11. The susceptor according to claim 10, wherein When viewed in the vertical direction, the plurality of wafer support portions are arranged at positions different from a position on a straight line extending in the prescribed direction passing through the rotation axis and are also arranged at positions different from a position on a straight line extending in a direction orthogonal to the prescribed direction passing through the rotation axis.

12. The susceptor according to claim 10, wherein When viewed in the vertical direction, the plurality of wafer support portions are arranged at positions different from a position on a straight line extending in a direction inclined by 45° with respect to the prescribed direction passing through the rotation axis.

13. The susceptor according to claim 10, wherein The plurality of wafer support portions include a pair of wafer support portions sandwiching the rotation axis when viewed in the vertical direction.

14. The susceptor according to claim 10, wherein The number of the plurality of wafer support portions is four or more.

15. The susceptor according to claim 10, wherein having a base portion independent of the plurality of wafer support portions, the base portion has a plurality of fixing hole portions opened in an upper side and arranged at intervals in the circumferential direction, the plurality of wafer support portions are respectively fixed inside the plurality of fixing hole portions and respectively protrude upward from inner surfaces of the plurality of fixing hole portions.

16. The susceptor according to claim 15, wherein in each of the plurality of wafer support portions, at least a part of an outer circumferential surface of a portion of the wafer support portion inside the fixing hole portion is arranged separated from the inner surface of the fixing hole portion.

17. The susceptor according to claim 16, wherein the plurality of wafer support portions respectively have: a main body portion extending in the vertical direction; and a protrusion portion provided to an outer circumferential surface of the main body portion, the protrusion portion is in contact with the inner surface of the fixing hole portion.

18. The susceptor according to claim 15, wherein the plurality of wafer support portions have a thermal conductivity lower than a thermal conductivity of the base portion.

19. A vapor phase growth apparatus, wherein, having: the susceptor according to any one of claims 10 to 18; A driving portion rotates the base around the rotation axis; and A heating portion is capable of heating the base.

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