Susceptor and vapor growth device

Abstract

To provide a susceptor capable of suppressing deterioration of a flatness of a wafer by suppressing the generation of a wafer deviation, and enhancing a uniformity of a thickness of a film formed onto a wafer front surface, and provide a vapor growth device.SOLUTION: A susceptor of an embodiment, is provided to a vapor growth device. In the susceptor, a wafer is mounted. The susceptor has a wafer supporting part. The wafer supporting part supports the wafer. The wafer supporting part has an annular shape. The wafer supporting part has a support surface. The support surface supports the wafer from a lower side. The support surface has an inclination surface. The inclination surface is connected to an inner edge of the wafer supporting part. The inclination surface is positioned onto an upper side as directed to an outside of a radial direction of the wafer supporting part.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present invention relate to a susceptor and a vapor phase deposition apparatus. [Background technology]

[0002] In a vapor phase growth apparatus, when a wafer is placed on a susceptor and when a film such as SiC is formed on the wafer surface, there is a possibility that the wafer may rotate relative to the susceptor and become misaligned. If such a wafer misalignment occurs, there is a possibility that the flatness of the wafer may decrease due to the SiC film being formed on the back surface of the wafer, and the uniformity of the thickness of the film formed on the wafer surface may decrease. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-174138 A Summary of the Invention [Problem to be solved by the invention]

[0004] The problem that the present invention aims to solve is to provide a susceptor and a vapor phase growth apparatus that can suppress the occurrence of wafer misalignment, suppress a decrease in wafer flatness, and increase the uniformity of the thickness of a film formed on the wafer surface. [Means for solving the problem]

[0005] A susceptor according to an embodiment is used in a vapor phase growth apparatus. A wafer is placed on the susceptor. The susceptor has a wafer support portion. The wafer support portion supports the wafer. The wafer support portion is annular. The wafer support portion has a support surface. The support surface supports the wafer from below. The support surface has an inclined surface. The inclined surface is connected to an inner edge of the wafer support portion. The inclined surface is located higher as it moves radially outward of the wafer support portion. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a cross-sectional view showing a vapor phase growth apparatus according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a part of the vapor phase growth apparatus according to the embodiment. [Diagram 3] FIG. 2 is a top view showing a part of the vapor phase growth apparatus according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing another part of the vapor phase growth apparatus according to the embodiment. [Diagram 5] FIG. 2 is an enlarged cross-sectional view showing a part of the vapor phase growth apparatus according to the embodiment. [Figure 6] FIG. 4 is a top view showing a part of a vapor phase growth apparatus according to a first modified example of an embodiment. [Figure 7] FIG. 4 is an enlarged cross-sectional view showing a part of a vapor phase growth apparatus according to a first modified example of the embodiment. [Figure 8] FIG. 13 is a top view showing a part of another vapor phase growth apparatus according to the first modified example of the embodiment. [Figure 9] FIG. 11 is a top view showing a part of a vapor phase growth apparatus according to a second modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, a susceptor and a vapor phase growth apparatus according to an embodiment will be described with reference to the drawings. In each drawing, the Z-axis direction is the vertical direction. The side toward which the Z-axis arrow points (+Z side) is the upper side in the vertical direction. The side opposite to the side toward which the Z-axis arrow points (-Z side) is the lower side in the vertical direction. In the following description, the upper side in the vertical direction will be simply referred to as the "upper side," and the lower side in the vertical direction will be simply referred to as the "lower side."

[0008] The direction in which the rotation axis J shown in each figure extends is parallel to the Z-axis direction. The rotation axis J is a virtual axis. In the following embodiments, the susceptor rotates around the rotation axis J. In the following description, the radial direction around the rotation axis J is simply referred to as the "radial direction". In the following embodiments, the radial direction of the wafer support is the same as the radial direction around the rotation axis J. The radial direction of the wafer support and the radial direction around the rotation axis J may be different directions. The circumferential direction around the rotation axis J is simply referred to as the "circumferential direction". In each figure, the circumferential direction is indicated by an arrow θ. In the following embodiments, the circumferential direction of the wafer support is the same as the circumferential direction around the rotation axis J. The circumferential direction of the wafer support and the circumferential direction around the rotation axis J may be different directions.

[0009] The vapor phase growth apparatus 10 of this embodiment shown in FIG. 1 is a film formation apparatus that forms an epitaxial film on a surface 60a, which is the surface facing upward, of a wafer 60 by a CVD (Chemical Vapor Deposition) method. In this embodiment, a SiC film is formed on the surface 60a of the wafer 60. The film formed on the surface 60a of the wafer 60 may be a film made of other materials such as Si. The vapor phase growth apparatus 10 includes a chamber 20, a supply pipe 24, a drive unit 31, a susceptor holding unit 32, a susceptor 34, a wafer guide 38, a first heating unit 41, and a second heating unit 42.

[0010] The chamber 20 accommodates therein a supply pipe 24, a drive unit 31, a susceptor holding unit 32, a susceptor 34, a wafer guide 38, a first heating unit 41, and a second heating unit 42. The chamber 20 has a main body unit 21 and a supply unit 22. In this embodiment, the chamber 20 is made of metal.

[0011] The main body 21 accommodates therein the supply pipe 24, the drive unit 31, the susceptor holding unit 32, the susceptor 34, the wafer guide 38, the first heating unit 41, and the second heating unit 42. The main body 21 has a cylindrical shape extending in the vertical direction. The main body 21 is provided with a main body opening 21a that opens to the upper side. The main body 21 is provided with an exhaust port 21b that opens to the lower side. Excess gas G in the chamber 20 is exhausted from the exhaust port 21b.

[0012] The supply unit 22 is fixed to the upper end of the main body 21. The supply unit 22 is cylindrical and protrudes vertically. The supply unit 22 is provided with a supply port 22a that opens to the upper side. The supply unit 22 is provided with a supply unit opening 22b that opens to the lower side. The inside of the supply unit 22 and the inside of the main body 21 are connected via the supply unit opening 22b and the main body opening 21a. The gas G supplied from the supply port 22a to the inside of the supply unit 22 is supplied to the inside of the main body 21 via the supply unit opening 22b and the main body opening 21a.

[0013] The supply pipe 24 is housed inside the main body 21. The supply pipe 24 is cylindrical and extends vertically. The supply pipe 24 opens both at the top and bottom. Inside the supply pipe 24, gas G flows downward. The gas G flowing downward inside the supply pipe 24 is supplied to the wafer 60. Excess gas G inside the supply pipe 24 is exhausted to the outside of the vapor phase growth apparatus 10 through the lower opening of the supply pipe 24 and the exhaust port 21b. In this embodiment, the supply pipe 24 is made of graphite. A coating layer made of a material such as SiC and TaC (tantalum carbide) may be provided on the surface of the supply pipe 24.

[0014] In this embodiment, the gas G contains a source gas, an impurity gas, a carrier gas, and hydrogen chloride (HCl) gas. The source gas contains silane (SiH4) and propane (C3H8). The flow rate of the source gas is preferably in the range of several tens [sccm] to several hundreds [sccm]. The impurity gas contains nitrogen and TMA (trimethylaluminum). The flow rate of the impurity gas is preferably in the range of several [sccm] to several hundreds [sccm]. The carrier gas is either argon gas or hydrogen gas. More specifically, the carrier gas is argon gas when the wafer 60 is carried into the vapor phase growth apparatus 10 and placed on the susceptor 34, and when the wafer 60 after film formation is removed from the susceptor 34 and carried out of the vapor phase growth apparatus 10. The carrier gas during film formation is hydrogen gas. The flow rate of the carrier gas is preferably in the range of 100 [slm] to 200 [slm]. The flow rate of the hydrogen chloride gas is preferably in the range of several tens of sccm to several slm. The flow rates of the source gas, impurity gas, carrier gas, and hydrogen chloride gas are adjusted by gas adjustment units (not shown).

[0015] The first heating section 41 is annular and surrounds the supply pipe 24. The first heating section 41 is disposed between the main body section 21 and the supply pipe 24. In this embodiment, the vapor phase growth apparatus 10 includes three first heating sections 41. The first heating sections 41 are disposed at intervals in the vertical direction. Each first heating section 41 heats the gas G passing through the inside of the supply pipe 24. This can increase the temperature of the gas G when it reaches the wafer 60, thereby increasing the deposition rate of the SiC film. The number of first heating sections 41 included in the vapor phase growth apparatus 10 may be two or less, or four or more.

[0016] The second heating section 42 is disposed inside the driving section 31. The second heating section 42 is disposed below the susceptor holding section 32. During film formation, the second heating section 42 heats each of the susceptor holding section 32, the susceptor 34, and the wafer 60. During film formation, the second heating section 42 heats the wafer 60 to a temperature of 1500° C. or more and 1650° C. or less. When gas G is supplied to the surface 60a of the wafer 60 heated to such a temperature and held for a certain period of time, a SiC film of a desired thickness is formed on the surface 60a of the wafer 60.

[0017] The driving unit 31 includes a driving device such as a motor (not shown). The driving unit 31 is rotated around the rotation axis J by the driving device. The driving unit 31 is disposed below the susceptor holding unit 32. The driving unit 31 is fixed to the susceptor holding unit 32. The driving unit 31 rotates each of the susceptor holding unit 32, the susceptor 34, the wafer guide 38, and the wafer 60 around the rotation axis J. Thus, according to this embodiment, during the film formation in which a SiC film is formed on the front surface 60a of the wafer 60, the driving unit 31 can rotate the wafer 60 around the rotation axis J. Therefore, the variation in the supply amount of gas G and the concentration of gas G within the surface 60a can be reduced. Therefore, the uniformity of the thickness of the film formed on the wafer 60 can be improved.

[0018] The susceptor holder 32 is in the form of a plate extending in a direction perpendicular to the vertical direction. In this embodiment, the susceptor holder 32 is in the form of a substantially circular plate centered on the rotation axis J. When viewed in the vertical direction, the susceptor holder 32 may be in another shape, such as a polygonal shape such as a square shape, or an elliptical shape. As described above, the drive unit 31 is fixed to the susceptor holder 32. As shown in FIG. 2, the susceptor 34 is fixed to the holder surface 32a, which is the surface of the susceptor holder 32 facing upward. In this way, the susceptor holder 32 holds the susceptor 34. In this embodiment, the susceptor holder 32 is made of graphite. The surface of the susceptor holder 32 may be provided with a coating layer made of materials such as SiC and TaC.

[0019] The wafer 60 is placed on the susceptor 34. The susceptor 34 supports the wafer 60 from below. In this embodiment, the susceptor 34 is substantially annular about the rotation axis J. As described above, the susceptor 34 is held by the susceptor holder 32. The susceptor 34 rotates about the rotation axis J. The susceptor 34 includes a guide support portion 35, a connection portion 36, and a wafer support portion 37. In this embodiment, the susceptor 34 is made of graphite. A coating layer made of materials such as SiC and TaC may be provided on the surface of the susceptor 34.

[0020] The guide support portion 35 has an annular shape centered on the rotation axis J. The guide support portion 35 is a radially outer portion of the susceptor 34. A surface of the guide support portion 35 facing downward contacts the susceptor holding portion 32 in the vertical direction.

[0021] The connection portion 36 protrudes radially inward from the guide support portion 35. The connection portion 36 is annular about the rotation axis J. The downward surface of the connection portion 36 contacts the susceptor holding portion 32 in the vertical direction. The upward surface of the connection portion 36 is located below the upward surface of the guide support portion 35. As shown in FIG. 3, the connection portion 36 has an exposed portion 36a. The exposed portion 36a is a part of the upward surface of the connection portion 36, and is a portion that overlaps with a gap between an orientation flat portion 60d of the wafer 60 described later and the guide support portion 35 when viewed from the vertical direction. The exposed portion 36a is exposed to the upper side through the gap between the orientation flat portion 60d and the guide support portion 35. Therefore, during film formation, a SiC laminate is formed on the exposed portion 36a.

[0022] The wafer support portion 37 extends in the circumferential direction. In this embodiment, the wafer support portion 37 is annular surrounding the rotation axis J. The wafer support portion 37 is disposed radially inward from the connection portion 36. The wafer support portion 37 is connected to the connection portion 36. As shown in FIG. 2, the upper end of the wafer support portion 37 is located above the upper end of the connection portion 36. The wafer support portion 37 is disposed radially inward from the wafer guide 38. The wafer support portion 37 has a support portion inner side surface 37d, a support surface 37e, and a support portion outer side surface 37i. As shown in FIG. 3, the wafer support portion 37 has an arc portion 37a, a straight portion 37b, and a plurality of recessed portions 37k. As shown in FIG. 2 and FIG. 4, the wafer 60 is placed on the wafer support portion 37. The wafer support portion 37 supports the wafer 60.

[0023] As shown in Fig. 2, wafer 60 has a generally circular disk shape that extends in a direction perpendicular to the vertical direction. In this embodiment, wafer 60 is made of SiC. Wafer 60 may be made of other materials such as Si. As shown in Fig. 3, wafer 60 has a linearly extending orientation flat 60d on part of its outer periphery. Orientation flat 60d is formed on wafer 60 to indicate the crystal orientation of wafer 60.

[0024] When the wafer 60 is heated by the second heating unit 42 during film formation, the temperature of the back surface 60b of the wafer 60 facing downward becomes higher than the temperature of the front surface 60a of the wafer 60. Thus, the thermal expansion of the back surface 60b of the wafer 60 becomes greater than the thermal expansion of the front surface 60a of the wafer 60. Therefore, as shown in FIG. 4, during film formation, the wafer 60 is thermally deformed such that the central portion in the radial direction is warped downward.

[0025] As shown in FIG. 3, the arc portion 37a is an arc-shaped portion of the wafer support portion 37 centered on the rotation axis J. In this embodiment, the central angle of the arc portion 37a is about 320°. The central angle of the arc portion 37a may be smaller than 320° or may be larger than 320°. The straight portion 37b is a portion of the wafer support portion 37 that extends linearly. Both ends of the straight portion 37b are connected to different circumferential ends of the arc portion 37a. The radially inner portion of the orientation flat portion 60d of the radially outer edge portion of the wafer 60 is supported by the straight portion 37b. The radially inner portion of the orientation flat portion 60d of the radially outer edge portion of the wafer 60 is supported by the arc portion 37a.

[0026] The support portion inner side surface 37d is the inner side surface of the wafer support portion 37. The support portion inner side surface 37d faces radially inward. The support portion inner side surface 37d is composed of the radially inner side surface of the arc portion 37a and the radially inner side surface of the straight portion 37b. The support portion outer side surface 37i is the outer side surface of the wafer support portion 37. The support portion outer side surface 37i faces radially outward. The support portion outer side surface 37i is composed of the radially outer side surface of the arc portion 37a and the radially outer side surface of the straight portion 37b.

[0027] When viewed in the vertical direction, the support surface 37e is annular and surrounds the rotation axis J. As shown in Fig. 2 and Fig. 4, the support surface 37e supports the wafer 60 from below. As shown in Fig. 5, the support surface 37e has an inclined surface 37f and a flat portion 37g.

[0028] The inclined surface 37f is connected to the upper end of the support inner side surface 37d. That is, the inclined surface 37f is connected to the inner edge of the wafer support 37. The inclined surface 37f is an inclined surface located on the upper side as it moves toward the radially outer side of the wafer support 37. Therefore, according to the present embodiment, as described above, even if the wafer 60 is thermally deformed into a shape warped downward during film formation, the back surface 60b of the wafer 60 and the inclined surface 37f are likely to come into surface contact with each other. Therefore, it is easy to prevent the contact area between the wafer 60 and the wafer support 37 from decreasing. This makes it possible to increase the frictional force between the wafer 60 and the wafer support 37. Therefore, even if the susceptor 34 on which the wafer 60 is placed is rotated during film formation, it is possible to prevent the wafer 60 from rotating relative to the susceptor 34 and causing other wafer misalignment. This makes it possible to improve the uniformity of the thickness of the film formed on the wafer 60.

[0029] In the susceptor 34 in which the wafer support 37 is not provided with the inclined surface 37f, when the wafer 60 is thermally deformed into a shape warped downward during film formation, the back surface 60b of the wafer 60 and the upper corners of the support inner surface 37d of the wafer support 37 rub against each other. Therefore, wear powder is likely to be generated in the wafer support 37. If such wear powder gets between the wafer 60 and the support surface 37e, the frictional force between the wafer 60 and the wafer support 37 decreases. Therefore, the wafer is likely to be misaligned during film formation. In contrast, in this embodiment, the wafer support 37 has the above-mentioned inclined surface 37f, so that the back surface 60b of the wafer 60 and the inclined surface 37f are easily brought into surface contact with each other. This makes it easy to prevent the back surface 60b of the wafer 60 and the corners of the wafer support 37 from rubbing against each other. Therefore, the generation of wear powder in the wafer support 37 can be suppressed, and the frictional force between the wafer 60 and the wafer support 37 can be increased. Therefore, the occurrence of wafer misalignment during film formation can be suppressed.

[0030] As described above, in this embodiment, the occurrence of wafer misalignment during film formation can be suppressed, and therefore the position of the orientation flat portion 60d of the wafer 60 relative to the susceptor 34 can be suppressed from being misaligned during film formation. This can suppress the stack of SiC stacked on the exposed portion 36a from facing the wafer 60 in the vertical direction. Therefore, during film formation, it can suppress a part of the stack of SiC sublimated by heating from adhering to the back surface 60b of the wafer 60. Therefore, it can suppress the flatness of the back surface 60b of the wafer 60 from decreasing. This can suppress the flatness of the wafer 60 from decreasing. In addition, when the vertical dimension of the stack of SiC stacked on the exposed portion 36a is large, it can suppress the wafer 60 from running over the SiC deposit. Therefore, since the wafer 60 can be suppressed from tilting during film formation, the uniformity of the thickness of the film formed on the wafer 60 can be improved.

[0031] As shown in FIG. 3, the inclined surface 37f extends in the circumferential direction of the wafer support part 37. The inclined surface 37f is annular and surrounds the rotation axis J. In this embodiment, the inclined surface 37f is divided into a plurality of portions by a plurality of recessed portions 37k. The inclined surface 37f is provided across the arc portion 37a and the straight portion 37b. Therefore, according to this embodiment, the back surface 60b of the wafer 60 and the inclined surface 37f can be brought into contact with each other along the circumferential direction during film formation. This can increase the contact area between the back surface 60b of the wafer 60 and the inclined surface 37f, so that the frictional force between the wafer 60 and the wafer support part 37 can be more suitably increased. Therefore, during film formation, the occurrence of wafer misalignment can be more suitably suppressed, so that the formation of a SiC film on the back surface 60b of the wafer 60 can be suppressed. Therefore, the flatness of the wafer 60 can be suppressed from decreasing. In addition, the uniformity of the thickness of the film formed on the wafer 60 can be more suitably increased.

[0032] As shown in FIG. 5, the flat portion 37g is a surface facing upward among the outer surfaces of the wafer support portion 37. The flat portion 37g extends in a direction perpendicular to the vertical direction. The flat portion 37g is connected to both the radially outer end of the inclined surface 37f and the upper end of the support portion outer surface 37i. Therefore, according to this embodiment, as shown in FIG. 2, when the wafer 60 is placed on the susceptor 34, the back surface 60b of the disk-shaped wafer 60 and the flat portion 37g can be in surface contact with each other. This can increase the frictional force between the wafer 60 and the wafer support portion 37. Therefore, when the wafer 60 is placed, the occurrence of wafer misalignment, such as the wafer 60 rotating relative to the susceptor 34, can be suppressed. As shown in FIG. 3, the flat portion 37g extends in the circumferential direction of the wafer support portion 37. The flat portion 37g is annular and surrounds the rotation axis J. In this embodiment, the flat portion 37g is divided into a plurality of portions by a plurality of recesses 37k.

[0033] The susceptor 34 has a susceptor groove 34a. The susceptor groove 34a is a groove recessed downward from the upward surface of the susceptor 34. The susceptor groove 34a is composed of the inner surface of the guide support part 35, the upward surface of the connection part 36, and the support part outer surface 37i. As shown in Fig. 3, the susceptor groove 34a is annular in shape surrounding the rotation axis J when viewed in the vertical direction.

[0034] Each of the plurality of recesses 37k is a recess recessed downward from the support surface 37e. The plurality of recesses 37k are arranged at intervals along the circumferential direction of the wafer support portion 37. In this embodiment, each recess 37k is a groove extending in the radial direction. As shown in FIG. 5, in this embodiment, each recess 37k is provided across the inclined surface 37f and the flat surface portion 37g. Therefore, as shown in FIG. 2, when the wafer 60 is placed on the susceptor 34, the back surface 60b of the wafer 60 and the portion of the upper corner of each recess 37k located on the flat surface portion 37g, that is, the radially outer portion of the upper corner of each recess 37k, come into contact with each other. Also, as shown in FIG. 4, during film formation, the back surface 60b of the wafer 60 and the portion of the upper corner of each recess 37k located on the inclined surface 37f, that is, the radially inner portion of the upper corner of each recess 37k come into contact with each other. Therefore, according to this embodiment, when the wafer 60 is rotated relative to the susceptor 34 during both placement and film formation, the back surface 60b of the wafer 60 is caught by the upper corners of the recesses 37k. This increases the frictional force between the wafer 60 and the wafer support 37. This more effectively prevents the wafer from shifting during both placement and film formation. This more effectively prevents the SiC film from being formed on the back surface 60b of the wafer 60, more effectively preventing the flatness of the wafer 60 from decreasing, and more effectively improving the uniformity of the thickness of the film formed on the wafer 60.

[0035] As shown in FIG. 3, in this embodiment, the wafer support 37 has 36 recesses 37k. The number of recesses 37k in the wafer support 37 may be 35 or less, or 37 or more. In this embodiment, each recess 37k opens to the support inner side 37d, i.e., the inner side of the wafer support 37, and the support outer side 37i, i.e., the outer side of the wafer support 37. Therefore, according to this embodiment, as shown in FIG. 2, when the wafer 60 is placed on the susceptor 34, the gas As in the lower space S, which is the space surrounded by the wafer 60, the susceptor 34, and the susceptor holder 32, can be exhausted to the outside of the susceptor 34 through each recess 37k. As a result, the wafer 60 can be stably supported by the support surface 37e of the wafer support 37 when placed. Therefore, when the wafer 60 is placed on the susceptor 34, the occurrence of wafer misalignment can be suppressed. Therefore, the decrease in the flatness of the wafer 60 can be more suitably prevented, and the uniformity of the thickness of the film formed on the wafer 60 can be more suitably improved.

[0036] Furthermore, according to this embodiment, even if the temperature of the gas As in the lower space S rises and the volume of the gas As increases during film formation, the gas As can be discharged to the outside of the susceptor 34 through each recess 37k. This allows the wafer 60 to be stably supported by the support surface 37e during film formation. Therefore, even if the susceptor 34 is rotated during film formation, the occurrence of wafer misalignment can be suppressed. Therefore, it is possible to more suitably suppress the reduction in flatness of the wafer 60 and more suitably improve the uniformity of the film formed on the wafer.

[0037] As shown in FIG. 2 and FIG. 4, the wafer guide 38 is annular around the rotation axis J. In this embodiment, the wafer guide 38 is annular around the rotation axis J. In this embodiment, the wafer guide 38 is made of poly-SiC. The wafer guide 38 may be made of graphite. In this case, a coating layer made of SiC may be provided on the surface of the wafer guide 38. In this embodiment, the wafer guide 38 and the susceptor 34 are different members. The wafer guide 38 and the susceptor 34 may be integrally molded. The wafer guide 38 is supported from below by the guide support portion 35 of the susceptor 34. The wafer guide 38 is supported by the guide support portion 35. The wafer guide 38 surrounds the outer edge of the wafer 60 from the radial outside. During film formation, a part of the inner surface of the wafer guide 38 comes into radial contact with the wafer 60 rotating around the rotation axis J, preventing the wafer 60 from jumping out of the wafer guide 38. Wear powder of the wafer guide 38 generated by rubbing between the inner surface of the wafer guide 38 and the wafer 60 is accommodated inside the susceptor groove 34a. This prevents the wear powder from entering between the wafer 60 and the support surface 37e, thereby preventing a decrease in the frictional force between the wafer 60 and the wafer support 37. This prevents the wafer from shifting during film formation.

[0038] The imaginary straight line Lv shown in FIG. 5 is an imaginary straight line passing through the radially inner end of the inclined surface 37f and the radially outer end of the inclined surface 37f. The imaginary straight line Lv intersects with the inner surface of the wafer guide 38 facing the radially inner side. During film formation, a centrifugal force is applied to the wafer 60 rotating around the rotation axis J, so that the wafer 60 tries to move radially outward. Also, as described above, during film formation, the wafer 60 is thermally deformed into a shape in which the central part in the radial direction is warped downward, and the back surface 60b of the wafer 60 comes into surface contact with the inclined surface 37f. Therefore, during film formation, the wafer 60 tries to move in a direction along the imaginary straight line Lv. In contrast, according to the present embodiment, as described above, the imaginary straight line Lv intersects with the inner surface of the wafer guide 38 facing the radially inner side. Therefore, the inner surface of the wafer guide 38 can be arranged in the direction in which the wafer 60 tries to move. Therefore, the movement of the wafer 60 can be restricted by the inner surface of the wafer guide , and therefore the wafer 60 can be restricted from jumping out of the wafer guide .

[0039] In this embodiment, the wafer support 37 does not have to have either the inclined surface 37f or the plurality of recesses 37k. If the wafer support 37 has either the inclined surface 37f or the plurality of recesses 37k, the frictional force between the back surface 60b of the wafer 60 and the wafer support 37 can be increased as described above. Therefore, the occurrence of wafer misalignment during placement and film formation can be suppressed.

[0040] (First Modification) 6 is a top view showing a part of a vapor phase growth apparatus 110 of this modified example. In the following description, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof may be omitted.

[0041] In this modification, as shown in FIG. 6, each of the plurality of recesses 137k provided in the wafer support 137 opens to the support inner side surface 37d. Each recess 137k does not open to the support outer side surface 37i. That is, each of the plurality of recesses 137k opens only to either the support inner side surface 37d, i.e., the inner side surface of the wafer support 137, or the support outer side surface 37i, i.e., the outer side surface of the wafer support 137. As shown in FIG. 8, each of the plurality of recesses 137k may open to the support outer side surface 37i. In this case, each recess 137k does not open to the support inner side surface 37d. Therefore, according to this modification, as shown in FIG. 7, during film formation, it is possible to suppress the gas G from flowing into the lower space S, which is a space surrounded by the wafer 60, the susceptor 134, and the susceptor holder 32, through each recess 137k. This can prevent a SiC film from being formed on the back surface 60b of the wafer 60. This can prevent a decrease in flatness of the back surface 60b of the wafer 60. This can prevent a decrease in flatness of the wafer 60. Other configurations of the susceptor 134 of this modified example are similar to those of the susceptor 34 of the above-described embodiment.

[0042] As described above, in this modification, each of the plurality of recesses 137k opens to the support inner side surface 37d. Thus, according to this modification, a part of each recess 137k is recessed downward from the inclined surface 37f. Therefore, even if the wafer 60 is thermally deformed into a shape warped downward during film formation, the back surface 60b of the wafer 60 and the part of the upper corner of each recess 137k located on the inclined surface 37f, that is, the part of the upper corner of each recess 137k that is located on the radially inner side, contact each other. Therefore, when the wafer 60 tries to rotate relative to the susceptor 134 during film formation, the back surface 60b of the wafer 60 gets caught by the upper corner of each recess 137k. This increases the frictional force between the wafer 60 and the wafer support 137, so that the occurrence of wafer misalignment can be more suitably suppressed. Therefore, the flatness of the wafer 60 can be suppressed from decreasing. In addition, the uniformity of the thickness of the film formed on the wafer 60 can be improved.

[0043] Furthermore, according to this modification, the wafer support 137 has an inclined surface 37f, as in the above embodiment. Therefore, even if the wafer 60 is thermally deformed into a shape warped downward during film formation, the back surface 60b of the wafer 60 and the inclined surface 37f are likely to come into surface contact with each other. This increases the frictional force between the wafer 60 and the wafer support 137. This prevents the wafer from shifting during film formation, thereby preventing the flatness of the wafer 60 from decreasing and improving the uniformity of the thickness of the film formed on the wafer 60.

[0044] (Second Modification) 9 is a top view showing a part of a vapor phase growth apparatus 210 of this modified example. In the following description, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0045] In this modification, as shown in FIG. 9, each of the recesses 237k provided in the wafer support 237 has a circular shape when viewed in the vertical direction. In this modification, each recess 237k does not open to either the support inner side surface 37d or the support outer side surface 37i. Therefore, according to this modification, as in the above-described first modification, the gas G can be prevented from flowing into the lower space S through each recess 237k during film formation. This can prevent a SiC film from being formed on the back surface 60b of the wafer 60. Therefore, it can prevent the flatness of the back surface 60b of the wafer 60 from decreasing. Other configurations of the susceptor 234 in this modification are the same as those of the susceptor 34 in the above-described embodiment.

[0046] In this modification, a part of each recess 237k is recessed downward from the inclined surface 37f. Therefore, even if the wafer 60 is thermally deformed to a shape warped downward during film formation, the back surface 60b of the wafer 60 and the part of the upper corner of each recess 237k located on the inclined surface 37f, that is, the part of the upper corner of each recess 237k located on the radially inner side, come into contact with each other. Therefore, when the wafer 60 tries to rotate relative to the susceptor 234 during film formation, the back surface 60b of the wafer 60 gets caught by the upper corner of each recess 237k. This increases the frictional force between the wafer 60 and the wafer support 237, so that the occurrence of wafer misalignment can be more suitably suppressed. Therefore, the flatness of the wafer 60 can be suppressed from decreasing, and the uniformity of the thickness of the film formed on the wafer 60 can be improved.

[0047] Also, according to this modification, the wafer support 237 has an inclined surface 37f, as in the above embodiment. Therefore, even if the wafer 60 is thermally deformed into a shape warped downward during film formation, the back surface 60b of the wafer 60 and the inclined surface 37f are likely to come into surface contact with each other. This makes it easy to prevent the frictional force between the wafer 60 and the wafer support 237 from decreasing. Therefore, during film formation, it is possible to prevent the wafer 60 from being misaligned, such as by rotation of the wafer 60 relative to the susceptor 234. This makes it possible to prevent the flatness of the wafer 60 from decreasing, and to improve the uniformity of the thickness of the film formed on the wafer 60.

[0048] According to the susceptor of the embodiment and the modified example described above, the support surface is connected to the inner edge of the wafer support part, and has an inclined surface that is positioned upward toward the radially outer side of the wafer support part, thereby making it possible to suppress the occurrence of wafer misalignment during film formation and to improve the uniformity of the thickness of the film formed on the wafer surface.

[0049] According to the susceptor of the embodiment and the modified example described above, the wafer support has a plurality of recesses recessed downward from the support surface. This allows the back surface of the wafer to come into contact with the upper corners of each recess when the wafer is placed on the susceptor and during film formation. Therefore, when the wafer is placed on the susceptor and during film formation, the back surface of the wafer is caught by the upper corners of each recess. This increases the frictional force between the wafer and the wafer support. Therefore, the wafer can be more suitably prevented from shifting when placed on the susceptor and during film formation. This prevents the flatness of the wafer from decreasing, and more suitably increases the uniformity of the thickness of the film formed on the wafer.

[0050] The present invention includes the following additional aspects. (Appendix 1) A susceptor for use in a vapor phase growth apparatus, on which a wafer is placed, comprising: a ring-shaped wafer support portion for supporting the wafer; the wafer support portion has a support surface that supports the wafer from below, the support surface has an inclined surface that is connected to an inner edge of the wafer support portion, The inclined surface is positioned higher toward the outer side in the radial direction of the wafer support portion. (Appendix 2) 2. The susceptor of claim 1, wherein the inclined surface extends in a circumferential direction of the wafer support portion. (Appendix 3) The support surface has a planar portion facing upward, 3. The susceptor according to claim 1, wherein the flat portion is connected to a radially outer end of the inclined surface. (Appendix 4) the wafer support portion has a plurality of recesses recessed downward from the support surface, 4. The susceptor according to claim 1, wherein the recesses are spaced apart from one another in a circumferential direction of the wafer support portion. (Appendix 5) A susceptor for use in a vapor phase growth apparatus, on which a wafer is placed, comprising: a ring-shaped wafer support portion for supporting the wafer; the wafer support portion has a support surface that supports the wafer from below, and a plurality of recesses that are recessed downward from the support surface, The plurality of recesses are arranged at intervals along a circumferential direction of the wafer support portion. (Appendix 6) 6. The susceptor according to claim 4 or 5, wherein at least one of the plurality of recesses opens to each of an inner surface of the wafer support and an outer surface of the wafer support. (Appendix 7) 6. The susceptor according to claim 4 or 5, wherein each of the plurality of recesses is open only to either an inner surface of the wafer support or an outer surface of the wafer support. (Appendix 8) 8. The susceptor of claim 7, wherein each of the plurality of recesses opens to an inner surface of the wafer support. (Appendix 9) 9. A vapor phase growth apparatus comprising: a susceptor according to any one of claims 1 to 8; and a drive unit that rotates the susceptor. (Appendix 10) A susceptor according to any one of claims 1 to 4, a drive unit that rotates the susceptor, and an annular wafer guide that surrounds an outer edge of the wafer, a virtual line passing through a radially inner end of the inclined surface and a radially outer end of the inclined surface intersects with an inner surface of the wafer guide.

[0051] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0052] 10, 110, 210... vapor phase growth apparatus, 31... drive unit, 34, 134, 234... susceptor, 37, 137, 237... wafer support unit, 37e... support surface, 37f... inclined surface, 37g... flat surface, 37k, 137k, 237k... recessed portion, 38... wafer guide, 60... wafer, Lv... virtual straight line

Claims

1. A susceptor for use in a vapor phase growth apparatus, on which a wafer is placed, comprising: a ring-shaped wafer support portion for supporting the wafer; the wafer support portion has a support surface that supports the wafer from below, the support surface has an inclined surface that is connected to an inner edge of the wafer support portion, The inclined surface is positioned higher toward the outer side in the radial direction of the wafer support portion.

2. The susceptor according to claim 1 , wherein the inclined surface extends in a circumferential direction of the wafer support portion.

3. The support surface has a planar portion facing upward, The susceptor according to claim 1 , wherein the flat portion is connected to an end portion of the inclined surface on a radially outer side.

4. the wafer support portion has a plurality of recesses recessed downward from the support surface, The susceptor according to claim 1 , wherein the recesses are spaced apart from one another along a circumferential direction of the wafer support portion.

5. A susceptor for use in a vapor phase growth apparatus, on which a wafer is placed, comprising: a ring-shaped wafer support portion for supporting the wafer; the wafer support portion has a support surface that supports the wafer from below, and a plurality of recesses that are recessed downward from the support surface, The plurality of recesses are arranged at intervals along a circumferential direction of the wafer support portion.

6. The susceptor according to claim 4 or 5, wherein at least one of the plurality of recesses opens to both an inner surface of the wafer support and an outer surface of the wafer support.

7. 6. The susceptor according to claim 4, wherein each of the plurality of recesses is open only to either an inner surface of the wafer support or an outer surface of the wafer support.

8. The susceptor according to claim 7 , wherein each of the plurality of recesses opens onto an inner surface of the wafer support.

9. A vapor phase growth apparatus comprising: the susceptor according to claim 1 ; and a drive unit that rotates the susceptor.

10. A wafer transport apparatus comprising: a susceptor according to claim 1; a drive unit that rotates the susceptor; and an annular wafer guide that surrounds an outer edge of the wafer, a virtual line passing through a radially inner end of the inclined surface and a radially outer end of the inclined surface intersects with an inner surface of the wafer guide.

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