Vapor phase growth apparatus

Abstract

The present invention provides a vapor phase growth apparatus that can improve the uniformity of the thickness of films deposited on the wafer surface. [Solution] The vapor phase growth apparatus 10 includes a susceptor 34 on which a wafer 60 is placed, a drive unit for rotating the susceptor, and a wafer guide 38 which is annular in shape surrounding the outer edge of the wafer and attached to the susceptor. The upper surface 38a of the wafer guide is located below a position 0.65 mm above the upper surface 60a of the wafer.

Description

Technical Field

[0001] Embodiments of the present invention relate to a vapor deposition apparatus.

Background Art

[0002] There is known a vapor deposition apparatus that enhances the uniformity of the film thickness by forming a film such as SiC on the surface of a wafer while rotating a susceptor on which the wafer is placed. In such a vapor deposition apparatus, in order to prevent the wafer from falling off the susceptor, a wafer guide may be provided that surrounds the susceptor and whose upper surface is positioned above the surface of the wafer. In this case, if the position of the upper surface of the wafer guide is too high, the flow rate of the material gas supplied to the outer edge in the radial direction of the wafer surface decreases, so that the film thickness formed on the outer edge in the radial direction of the wafer may become thin. Therefore, there is a risk that the uniformity of the film thickness may decrease.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a vapor deposition apparatus capable of enhancing the uniformity of the film thickness formed on the wafer surface.

Means for Solving the Problems

[0005] The vapor deposition apparatus according to the embodiment includes a susceptor on which a wafer is placed, a drive unit that rotates the susceptor, and a wafer guide that is annular and surrounds the outer edge of the wafer and is attached to the susceptor. The surface facing the upper side of the wafer guide is positioned below the position 0.65 mm above the surface facing the upper side of the wafer.

Brief Description of the Drawings

[0006] [Figure 1] A cross-sectional view showing a vapor phase growth apparatus according to an embodiment. [Figure 2] A first cross-sectional view showing a part of the vapor phase growth apparatus of the embodiment. [Figure 3] A second cross-sectional view showing a part of the vapor phase growth apparatus of the embodiment. [Figure 4] A cross-sectional view showing the flow of the material gas in a comparative example vapor phase growth apparatus. [Figure 5] A first cross-sectional view showing the flow of the material gas in the vapor phase growth apparatus of the embodiment. [Figure 6] A diagram showing the film deposition rate at the radial outer edge of the wafer in the vapor phase growth apparatus of the embodiment. [Figure 7] This figure shows the variation in the film deposition rate of the film deposited on the wafer surface of the vapor phase growth apparatus of the embodiment. [Figure 8] A second cross-sectional view showing the flow of the material gas in the vapor phase growth apparatus of the embodiment. [Figure 9] A diagram showing the film deposition rate in the wafer guide of the vapor phase growth apparatus of the embodiment. [Modes for carrying out the invention]

[0007] In each drawing, the Z-axis direction is the vertical direction. The side indicated by the Z-axis arrow (+Z side) is the upper side in the vertical direction. The side opposite to the side indicated by the Z-axis arrow (-Z side) is the lower side in the vertical direction. In the following explanation, 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." In the following explanation, the surface of each part constituting the vapor phase growth apparatus that faces upwards will be referred to as the front surface, and the surface that faces downwards will be referred to as the back surface.

[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 vapor phase growth apparatus of this embodiment, the susceptor rotates about the rotation axis J. In the following description, the radial direction about the rotation axis J will be simply referred to as the "radial direction," and the circumferential direction about the rotation axis J will be simply referred to as the "circumferential direction." In each figure, the circumferential direction is indicated by the arrow θ.

[0009] In this specification, terms such as "orthogonal," "parallel," "identical," and "similar," as well as values ​​for length and angle, which specify the shape of each part constituting a vapor phase growth apparatus and the degree of their relative arrangement, shall not be strictly interpreted, but shall be interpreted to include a range within which similar functions can be expected and within the range of design tolerances. Furthermore, each drawing is schematic and conceptual, and the dimensions of each part constituting the vapor phase growth apparatus, as well as the ratios of dimensions between each part, are not necessarily identical to those of the actual apparatus. Moreover, even when representing the same part, the dimensions and ratios may be represented differently in each drawing.

[0010] The vapor phase growth apparatus 10 of this embodiment, shown in Figure 1, is a film deposition apparatus that deposits an epitaxial film on the surface 60a of a wafer 60, i.e., the surface facing upward, by the CVD (Chemical Vapor Deposition) method. In this embodiment, a SiC (silicon carbide) film is deposited on the surface 60a of the wafer 60. The film deposited on the surface 60a of the wafer 60 may be a film composed of other materials such as Si. The vapor phase growth apparatus 10 comprises 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.

[0011] The chamber 20 houses 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 chamber 20 has a main body 21 and a supply unit 22. In this embodiment, the chamber 20 is made of metal.

[0012] The main body 21 houses 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 is cylindrical and extends vertically. The main body 21 is provided with a main body opening 21a that opens upwards. The main body 21 is provided with an outlet 21b that opens downwards. Excess material gas G in the chamber 20 is discharged to the outside of the vapor phase growth apparatus 10 through the outlet 21b.

[0013] The supply unit 22 is cylindrical and protrudes upward from the main body 21. The supply unit 22 is provided with a supply port 22a that opens upward. The supply unit 22 is also provided with a supply opening 22b that opens downward. The inside of the supply unit 22 and the inside of the main body 21 are connected via the supply opening 22b and the main body opening 21a. The material gas G supplied to the inside of the supply unit 22 from the supply port 22a is supplied to the inside of the main body 21 via the supply opening 22b and the main body opening 21a.

[0014] The supply pipe 24 is housed inside the main body 21. The supply pipe 24 is cylindrical and extends vertically. The supply pipe 24 has openings on both the upper and lower sides. During film formation, the material gas G flows downward inside the supply pipe 24. During film formation, the material gas G flowing downward inside the supply pipe 24 is supplied to the surface 60a of the wafer 60. Excess material gas G inside the supply pipe 24 is discharged to the outside of the vapor phase growth apparatus 10 through the lower opening and outlet 21b of the supply pipe 24. In this embodiment, the supply pipe 24 is made of graphite. A coating layer made of materials such as SiC and TaC (tantalum carbide) may be provided on the inner surface of the supply pipe 24.

[0015] In this embodiment, the material gas G contains a raw material gas, an impurity gas, a carrier gas, and hydrogen chloride (HCl) gas. The raw material gas contains silane (SiH4) and propane (C3H8). The flow rate of the raw material gas is preferably in the range of tens [sccm] to 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 hundreds [sccm]. The carrier gas is either argon gas or hydrogen gas. More specifically, the carrier gas when the wafer 60 is brought 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 transported out of the vapor phase growth apparatus 10, is argon gas. 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 hydrogen chloride gas is preferably in the range of several tens [sccm] to several [slm]. The flow rates of the raw material gas, impurity gas, carrier gas, and hydrogen chloride gas are adjusted by a gas adjustment unit (not shown).

[0016] The first heating section 41 is annular in shape, surrounding the supply pipe 24. The first heating section 41 is located between the main body 21 and the supply pipe 24. In this embodiment, the vapor phase growth apparatus 10 is equipped with three first heating sections 41. Each first heating section 41 is spaced apart in the vertical direction. Each first heating section 41 heats the material gas G passing through the inside of the supply pipe 24. This increases the temperature of the material gas G when it reaches the wafer 60, thereby increasing the rate of SiC film deposition. In addition, the silane and propane contained in the material gas G are thermally decomposed into silylene (SiH2) and methane (CH4), respectively. The number of first heating sections 41 in the vapor phase growth apparatus 10 may be two or fewer, or four or more.

[0017] The second heating unit 42 is disposed inside the drive unit 31. The second heating unit 42 is disposed below the susceptor holding unit 32. During film formation, the second heating unit 42 heats each of the susceptor holding unit 32, the susceptor 34, and the wafer 60. During film formation, the second heating unit 42 heats the wafer 60 to a temperature of 1500°C or higher and 1650°C or lower. When the material gas G is supplied to the surface 60a of the wafer 60 heated to such a temperature, a SiC film is formed on the surface 60a of the wafer 60.

[0018] The drive unit 31 includes a drive device such as a motor (not shown). The drive unit 31 is rotated about the rotation axis J by the drive device. The drive unit 31 is rotatably supported about the rotation axis J at the bottom of the main body unit 21. The drive unit 31 is disposed below the susceptor holding unit 32. The drive unit 31 rotates each of the susceptor holding unit 32, the susceptor 34, the wafer guide 38, and the wafer 60 about the rotation axis J. Thereby, in the vapor deposition apparatus 10 of the present embodiment, during film formation of the SiC film on the surface 60a of the wafer 60, the drive unit 31 can rotate the wafer 60 about the rotation axis J. Therefore, variations in the supply amount of the material gas G on the surface 60a of the wafer 60 can be reduced. Accordingly, the uniformity of the thickness of the film formed on the surface 60a of the wafer 60 can be enhanced.

[0019] The susceptor holding unit 32 is plate-shaped and extends in a direction orthogonal to the vertical direction. In the present embodiment, the susceptor holding unit 32 is substantially disk-shaped about the rotation axis J. When viewed from the vertical direction, the susceptor holding unit 32 may have another shape such as an elliptical shape. As shown in FIG. 2, the susceptor 34 is fixed to the surface 32a of the susceptor holding unit 32. Thereby, the susceptor holding unit 32 holds the susceptor 34. In the present embodiment, the susceptor holding unit 32 is made of graphite. A coat layer made of a material such as SiC and TaC may be provided on the outer surface of the susceptor holding unit 32.

[0020] A 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 in shape with a rotation axis J as its center. As described above, the susceptor 34 is held by the susceptor holding portion 32. The susceptor 34 has a holding portion 35 and a cover base 36.

[0021] The retaining portion 35 is substantially annular in shape with respect to the axis of rotation J. The retaining portion 35 is positioned above the susceptor retaining portion 32. The back surface 35b of the retaining portion 35 is fixed to the surface 32a of the susceptor retaining portion 32. The outer diameter of the retaining portion 35 and the outer diameter of the susceptor retaining portion 32 are substantially the same. The retaining portion 35 is provided with a retaining groove 35d and a protrusion 35e. The retaining groove 35d is recessed downward from the surface 35a of the retaining portion 35. The retaining groove 35d is open radially inward. The protrusion 35e is a projection that protrudes upward from the surface 35a of the retaining portion. The protrusion 35e is substantially annular in shape with respect to the axis of rotation J. In this embodiment, the retaining portion 35 is made of graphite. The outer surface of the retaining portion 35 may be provided with a coating layer made of materials such as SiC and TaC.

[0022] The cover base 36 is substantially annular in shape with respect to the axis of rotation J. The cover base 36 is located inside the retaining groove 35d. The back surface 36b of the cover base 36 is fixed to the surface facing upwards to the retaining groove 35d. In this embodiment, the surface 36a of the cover base 36 is located above the surface 35a of the retaining portion 35. In the vertical direction, the surface 36a of the cover base 36 may be in the same position as the surface 35a of the retaining portion 35. The cover base 36 supports the wafer guide 38 from below. During film formation, the wafer 60 is placed on the surface 36a of the cover base 36. As a result, the wafer 60 is placed on the susceptor 34. In this embodiment, the cover base 36 is made of graphite. A coating layer made of materials such as SiC and TaC may be provided on the outer surface of the cover base 36. In this embodiment, the retaining portion 35 and the cover base 36 are different components. The retaining portion 35 and the cover base 36 may be integrally molded.

[0023] The wafer guide 38 is annular in shape, surrounding the axis of rotation J. In this embodiment, the wafer guide 38 is substantially annular in shape, centered on the axis of rotation J. The wafer guide 38 is positioned above the cover base 36. The inner diameter of the wafer guide 38 is larger than the inner diameter of the cover base 36. The wafer guide 38 is provided with a recess 38d. The recess 38d is a recess that extends upward from the back surface 38b of the wafer guide 38. Viewed from below, the recess 38d is substantially annular in shape, centered on the axis of rotation J. A protrusion 35e is housed inside the recess 38d. The protrusion 35e is engaged with the recess 38d. As a result, the wafer guide 38 can rotate around the axis of rotation J together with the susceptor 34. The outer diameter of the wafer guide 38 is substantially the same as the outer diameter of the holding portion 35. During film formation, the wafer guide 38 surrounds the outer edge of the wafer 60 placed on the cover base 36 from the radially outer side. The inner diameter of the wafer guide 38 is slightly larger than the outer diameter of the wafer 60. During film formation, the inner surface of the wafer guide 38 contacts the wafer 60 radially as it rotates around the rotation axis J. This prevents the wafer 60 from falling off the susceptor 34 during film formation. The thickness Tg of the wafer guide 38 shown in Figure 2 is the vertical dimension of the wafer guide 38. In this embodiment, the wafer guide 38 is made of poly-SiC. The wafer guide 38 may also be made of graphite. In this case, a coating layer made of SiC may be provided on the surface of the wafer guide 38.

[0024] The wafer 60 is substantially disc-shaped, extending in a direction perpendicular to the vertical direction. In this embodiment, the wafer 60 is made of SiC. More specifically, in this embodiment, the wafer 60 is made of single-crystal SiC. The wafer 60 may also be made of polycrystalline SiC. The material constituting the wafer 60 may be other materials such as Si. During film formation, the wafer 60 is placed on the radially inward portion of the surface 36a of the cover base 36. The back surface 60b of the wafer 60 is in vertical contact with the surface 36a of the cover base 36. In this embodiment, the thickness Tw of the wafer 60 is 0.35 mm. The thickness Tw of the wafer 60 is the vertical dimension of the wafer 60. The thickness Tw of the wafer 60 may be thinner than 0.35 mm or thicker than 0.35 mm. In this embodiment, the thickness of the SiC film formed on the surface 60a of the wafer 60 is 0.5 to 100 μm.

[0025] The protrusion height La shown in Figure 2 is the distance in the vertical direction between the surface 38a of the wafer guide 38 and the surface 60a of the wafer 60. As described above, in this embodiment, the wafer guide 38 and the wafer 60 are each supported from below by the cover base 36. Therefore, in this embodiment, the protrusion height La is the difference between the thickness Tg of the wafer guide 38 and the thickness Tw of the wafer 60. In this embodiment, as shown in Figure 2, when the thickness Tg of the wafer guide 38 is thicker than the thickness Tw of the wafer 60, that is, when the surface 38a of the wafer guide 38 is located above the surface 60a of the wafer 60, the protrusion height La is a positive value. Although not shown in the figure, when the thickness Tg of the wafer guide 38 and the thickness Tw of the wafer 60 are the same, the protrusion height La is 0. In this embodiment, as shown in Figure 3, when the thickness Tg of the wafer guide 38 is thinner than the thickness Tw of the wafer 60, that is, when the surface 38a of the wafer guide 38 is located below the surface 60a of the wafer 60, the protrusion height La is a negative value. In this embodiment, the protrusion height La is 0.65 mm or less. That is, in this embodiment, the surface 38a of the wafer guide 38, i.e., the surface facing upward, is located below a position 0.65 mm above the surface 60a of the wafer 60, i.e., the surface facing upward. In this embodiment, the thickness Tg of the wafer guide 38 is less than 1.00 mm.

[0026] The thickness Tg of the wafer guide 138 in the comparative example vapor phase growth apparatus 110 shown in Figure 4 is, for example, 1.85 mm. Therefore, in the comparative example vapor phase growth apparatus 110, the protrusion height La is, for example, 1.50 mm. In the comparative example vapor phase growth apparatus 110, the surface 138a of the wafer guide 138 is located above a position 0.65 mm above the surface 60a of the wafer 60. As described above, during film deposition to deposit a SiC film on the surface 60a of the wafer 60, the material gas G flowing downward inside the supply pipe 24 shown in Figure 1 is supplied to the surface 60a of the wafer 60. Also, as described above, during film deposition, when the material gas G is supplied to the surface 60a of the wafer 60 heated by the second heating unit 42, a SiC film is deposited on the surface 60a of the wafer 60.

[0027] As shown in Figure 4, during film formation, the material gas G supplied to the surface 60a of the wafer 60 flows radially outward along the surface 60a of the wafer 60. This allows the material gas G to be supplied to the entire surface 60a of the wafer 60. However, if the protrusion height La is too large, as in the comparative example vapor phase growth apparatus 110, the wafer guide 138 significantly obstructs the flow of the material gas G flowing radially outward from the radial outer edge of the wafer 60. As a result, the flow velocity of the material gas G at the radial outer edge of the wafer 60 decreases significantly, and the film formation rate GR1 at the radial outer edge of the surface 60a of the wafer 60 decreases significantly. Consequently, the thickness of the film formed on the radial outer edge of the wafer 60 becomes too thin compared to the thickness of the film formed in the radial center of the wafer 60, making it difficult to improve the uniformity of the film thickness formed on the surface 60a of the wafer 60.

[0028] In contrast, as described above, in the vapor phase growth apparatus 10 of this embodiment, the protrusion height La is less than 0.65 mm. Therefore, it is possible to suppress the protrusion height La from becoming too large. Accordingly, as shown in Figure 5, in this embodiment, the wafer guide 38 can suppress obstruction of the flow of material gas G flowing from the radial outer edge of the wafer 60 toward the radially outward side of the wafer 60. As a result, it is possible to suppress a decrease in the flow velocity of material gas G at the radial outer edge of the wafer 60, and thus suppress a decrease in the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60. Accordingly, it is possible to suppress the thickness of the film deposited on the radial outer edge of the wafer 60 from becoming too thin compared to the thickness of the film deposited in the radial center of the wafer 60, and thus improve the uniformity of the film thickness deposited on the surface 60a of the wafer 60.

[0029] Figure 6 shows the film deposition rate GR1 at the radial outer edge of the wafer 60 of the vapor phase growth apparatus 10 of this embodiment. The horizontal axis of Figure 6 is the protrusion height La. The vertical axis of Figure 6 is the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60. In this embodiment, the film deposition rate GR2 at the radial center of the surface 60a of the wafer 60 is approximately 44 μm / h. Figure 7 shows the variation in the film deposition rate of the film deposited on the surface 60a of the wafer 60 of the vapor phase growth apparatus 10 of this embodiment. In the following description, the variation in the film deposition rate of the film deposited on the surface 60a may be referred to as the film deposition rate variation ΔGR. In this embodiment, when the maximum film deposition rate within the surface 60a is GRmax, the maximum film deposition rate within the surface 60a is GRmin, and the average film deposition rate within the surface 60a is GRave, the film deposition rate variation ΔGR is (GRmax - GRmin) / (2 × GRave). The horizontal axis in Figure 7 represents the projection height La. The vertical axis in Figure 7 represents the deposition rate variation ΔGR.

[0030] As shown in Figure 6, the deposition rate GR1 decreases as the protrusion height La increases. This is because, as described above, the flow velocity of the material gas G at the radial outer edge of the wafer 60 decreases as the protrusion height La increases. In the range where the protrusion height La is greater than 0.65 mm, the deposition rate GR1 decreases significantly as the protrusion height La increases. This is because the flow velocity of the material gas G at the radial outer edge of the wafer 60 decreases significantly as the protrusion height La becomes too large. Therefore, in the range where the protrusion height La is greater than 0.65 mm, the difference between the deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 and the deposition rate GR2 at the radial center of the surface 60a of the wafer 60 becomes large. Consequently, as shown in Figure 7, when the protrusion height La is greater than 0.65 mm, that is, when the surface 38a of the wafer guide 38 is located above a position 0.65 mm above the surface 60a of the wafer 60, the deposition rate variation ΔGR becomes large. This reduces the uniformity of the thickness of the film deposited on the surface 60a of the wafer 60.

[0031] In contrast, as shown in Figure 6, in the range where the protrusion height La is less than 0.65 mm, the film deposition rate GR1 decreases gradually as the protrusion height La increases. This is because it is possible to suppress the protrusion height La from becoming too large, thereby suppressing the decrease in the flow velocity of the material gas G at the radial outer edge of the wafer 60. Therefore, in the range where the protrusion height La is less than 0.65 mm, the difference between the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 and the film deposition rate GR2 at the radial center of the surface 60a of the wafer 60 can be reduced. Consequently, as shown in Figure 7, when the protrusion height La is less than 0.65 mm, that is, when the surface 38a of the wafer guide 38 is located below a position 0.65 mm above the surface 60a of the wafer 60, the film deposition rate variation ΔGR can be reduced. This makes it possible to improve the uniformity of the thickness of the film deposited on the surface 60a of the wafer 60.

[0032] In this embodiment, it is preferable that the surface 38a of the wafer guide 38, i.e., the surface facing upward, is located below a position 0.15 mm above the surface 60a of the wafer 60, i.e., the surface facing upward. In other words, it is preferable that the protrusion height La is less than 0.15 mm. This allows for a more favorable suppression of the decrease in the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60, as shown in Figure 6. Therefore, the difference between the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 and the film deposition rate GR2 at the radial center of the surface 60a of the wafer 60 can be more favorably reduced. Consequently, as shown in Figure 7, the variation in film deposition rate ΔGR can be more favorably reduced, and the uniformity of the film thickness can be more favorably improved.

[0033] In this embodiment, it is preferable that the surface 38a of the wafer guide 38, i.e., the surface facing upward, is located above a position 0.20 mm below the surface 60a of the wafer 60, i.e., the surface facing upward. In other words, it is preferable that the protrusion height La is greater than -0.20 mm. As shown in Figure 6, the film deposition rate GR1 increases as the protrusion height La decreases. In this embodiment, when the protrusion height La is less than -0.20 mm, the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 becomes greater than the film deposition rate GR2 at the radial center of the surface 60a of the wafer 60. Therefore, as shown in Figure 7, the film deposition rate variation ΔGR increases as the protrusion height La becomes less than -0.20 mm. This reduces the uniformity of the film thickness deposited on the surface 60a of the wafer 60. In contrast, by increasing the protrusion height La to more than -0.20 mm, it is possible to suppress the deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 from becoming greater than the deposition rate GR2 at the radial center of the surface 60a of the wafer 60. Therefore, the deposition rate variation ΔGR can be reduced, and the uniformity of the film thickness can be improved.

[0034] As shown in Figure 5, in this embodiment, during film formation, the material gas G flowing from the radial outer edge of the wafer 60 toward the radially outward direction of the wafer 60 flows radially outward along the surface 38a of the wafer guide 38. Therefore, as shown in Figure 8, a SiC film is formed on the surface 38a of the wafer guide 38 during film formation. When the thickness of the SiC film formed on the surface 38a of the wafer guide 38 increases, the flow of the material gas G flowing from the radial outer edge of the wafer 60 toward the radially outward direction of the wafer 60 is obstructed by this SiC film. As a result, the flow velocity of the material gas G at the radial outer edge of the wafer 60 decreases significantly, and the film formation rate GR1 at the radial outer edge of the surface 60a of the wafer 60 decreases significantly. In particular, when the thickness Ts of the SiC film at the radial inner edge of the wafer guide 38 increases, the flow of the material gas G flowing from the radial outer edge of the wafer 60 toward the radially outward direction of the wafer 60 is significantly obstructed. Therefore, in this embodiment, when the thickness Ts of the SiC film at the radial inner edge of the wafer guide 38 reaches a predetermined thickness, the wafer guide 38 is replaced. This prevents a decrease in the uniformity of the film deposited on the surface 60a of the wafer 60.

[0035] Figure 9 shows the film deposition rate GRs in the wafer guide 38 of the vapor phase growth apparatus 10 of this embodiment. The horizontal axis in Figure 9 represents the protrusion height La. The vertical axis in Figure 9 represents the film deposition rate GRs of the SiC film deposited on the surface 38a of the wafer guide 38. The film deposition rate GRs at the radial inner edge of the wafer guide 38 is shown by a solid line. The film deposition rate GRs at the radial center of the wafer guide 38 is shown by a dashed line.

[0036] As shown in Figure 9, the film deposition rate GRs at the radial center of the wafer guide 38, indicated by the dashed line, remains stable in the range of 40 [μm / h] to 50 [μm / h], regardless of the protrusion height La. In contrast, the film deposition rate GRs at the radial inner edge of the wafer guide 38, indicated by the solid line, decreases as the protrusion height La decreases. This is thought to be due to the decrease in the amount of material gas G accumulating at the radial outer edge of the wafer 60 as the protrusion height La decreases, thereby reducing the flow velocity of the material gas G flowing along the radial inner edge of the wafer guide 38. In this embodiment, when the protrusion height La is less than 0.00 mm, that is, when the surface 38a of the wafer guide 38 is located below the surface 60a of the wafer 60, the film deposition rate GRs at the radial inner edge of the wafer guide 38 is smaller than the film deposition rate GRs at the radial center of the wafer guide 38. This allows for an increase in the number of wafers 60 that can be coated with a SiC film before the SiC film thickness Ts at the radial inner edge of the wafer guide 38 reaches a predetermined thickness, when using a single wafer guide 38 continuously to deposit a SiC film on multiple wafers 60. In other words, the number of wafers 60 that can be coated with a single wafer guide 38 can be increased. Therefore, the frequency of replacing the wafer guide 38 can be reduced.

[0037] According to this embodiment, the vapor phase growth apparatus 10 includes a susceptor 34 on which a wafer 60 is placed, a drive unit 31 for rotating the susceptor 34, and a wafer guide 38 which is annular in shape surrounding the outer edge of the wafer 60 and attached to the susceptor 34. The surface 38a of the wafer guide 38, i.e., the surface facing upward, is located below a position 0.65 mm above the surface 60a of the wafer 60, i.e., the surface facing upward. As described above, if the protrusion height La, which is the distance between the surface 38a of the wafer guide 38 and the surface 60a of the wafer 60 in the vertical direction, becomes too large, the flow of material gas G flowing from the radial outer edge of the wafer 60 toward the radially outward direction of the wafer 60 is significantly obstructed by the wafer guide 38. As a result, as described above, the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 decreases significantly, and the thickness of the film deposited on the radial outer edge of the wafer 60 becomes thinner. Therefore, it is difficult to improve the uniformity of the thickness of the film deposited on the surface 60a of the wafer 60. In contrast, in this embodiment, since the protrusion height La is 0.65 mm or less, it is possible to suppress the protrusion height La from becoming too large. As a result, as described above, the difference between the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 and the film deposition rate GR2 at the radial center of the surface 60a of the wafer 60 can be reduced. Therefore, the uniformity of the thickness of the film deposited on the surface 60a of the wafer 60 can be improved.

[0038] According to this embodiment, the surface 38a of the wafer guide 38, i.e., the surface facing upward, is located below a position 0.15 mm above the surface 60a of the wafer 60, i.e., the surface facing upward. This makes it possible to more effectively suppress the decrease in the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60, as described above. Therefore, the difference between the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 and the film deposition rate GR2 at the radial center of the surface 60a of the wafer 60 can be more effectively reduced. Consequently, the uniformity of the film thickness deposited on the surface 60a of the wafer 60 can be more effectively improved.

[0039] According to this embodiment, the surface 38a of the wafer guide 38, i.e., the surface facing upward, is located below the surface 60a of the wafer 60, i.e., the surface facing upward. As a result, as described above, the film deposition rate GRs at the radial inner edge of the wafer guide 38 can be made smaller than the film deposition rate GRs at the radial center of the wafer guide 38. Therefore, as described above, when one wafer guide 38 is used continuously to deposit a SiC film on multiple wafers 60, the number of wafers 60 that can be coated before the SiC film thickness Ts at the radial inner edge of the wafer guide 38 reaches a predetermined thickness can be increased. As a result, the number of wafers 60 that can be coated with one wafer guide 38 can be increased. Consequently, the frequency of replacing the wafer guide 38 can be reduced, and the workability of the SiC film deposition process on wafers 60 can be improved.

[0040] Furthermore, in this embodiment, the protrusion height La can be reduced to 0.00 mm or less, which more effectively prevents the protrusion height La from becoming too large. As a result, as shown in Figure 6, the decrease in the film deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 can be more effectively suppressed. Therefore, the uniformity of the film thickness deposited on the surface 60a of the wafer 60 can be more effectively improved.

[0041] According to this embodiment, the surface 38a of the wafer guide 38, i.e., the surface facing upward, is located above a position 0.20 mm below the surface 60a of the wafer 60, i.e., the surface facing upward. This makes it possible to suppress the deposition rate GR1 at the radial outer edge of the surface 60a of the wafer 60 from becoming greater than the deposition rate GR2 at the radial center of the surface 60a of the wafer 60, as described above. Therefore, the uniformity of the thickness of the film deposited on the surface 60a of the wafer 60 can be improved.

[0042] In the vapor phase growth apparatus of the embodiment described above, the upper-facing surface of the wafer guide is located below a position 0.65 mm above the upper-facing surface of the wafer. This makes it possible to improve the uniformity of the thickness of the film deposited on the wafer surface.

[0043] The present invention includes the following appended embodiments. (Note 1) The susceptor on which the wafer is placed, A drive unit for rotating the susceptor, A wafer guide that is an annular shape surrounding the outer edge of the wafer and attached to the susceptor, Equipped with, A vapor phase growth apparatus in which the upper-facing surface of the wafer guide is located below a position 0.65 mm above the upper-facing surface of the wafer. (Note 2) The vapor phase growth apparatus as described in Appendix 1, wherein the upper-facing surface of the wafer guide is located below a position 0.15 mm above the upper-facing surface of the wafer. (Note 3) The vapor phase growth apparatus according to Appendix 1 or Appendix 2, wherein the upper-facing surface of the wafer guide is located below the upper-facing surface of the wafer. (Note 4) The vapor phase growth apparatus according to any one of the appendices 1 to 3, wherein the upper-facing surface of the wafer guide is located above a position 0.20 mm below the upper-facing surface of the wafer.

[0044] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0045] 10…Vapor phase growth apparatus, 31…Drive unit, 34…Susceptor, 38…Wafer guide, 38a…Surface of wafer guide (side facing upwards of the wafer guide), 60…Wafer, 60a…Surface of wafer (side facing upwards of the wafer)

Claims

1. The susceptor on which the wafer is placed, A drive unit for rotating the susceptor, A wafer guide that is an annular shape surrounding the outer edge of the wafer and attached to the susceptor, Equipped with, A vapor phase growth apparatus in which the upper-facing surface of the wafer guide is located below a position 0.65 mm above the upper-facing surface of the wafer.

2. The vapor phase growth apparatus according to claim 1, wherein the upper-facing surface of the wafer guide is located below a position 0.15 mm above the upper-facing surface of the wafer.

3. The vapor phase growth apparatus according to claim 1 or 2, wherein the surface of the wafer guide facing upward is located below the surface of the wafer facing upward.

4. The vapor phase growth apparatus according to claim 1 or 2, wherein the upper-facing surface of the wafer guide is located above a position 0.20 mm below the upper-facing surface of the wafer.

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