Silicon carbide semiconductor wafer manufacturing equipment

Abstract

To provide a manufacturing apparatus for a silicon carbide semiconductor wafer, in which film deposition on a back surface side of a wafer can be suppressed while formation of a deposit on a pedestal of the susceptor is suppressed.SOLUTION: A manufacturing apparatus 1 for a silicon carbide semiconductor wafer includes a chamber 12 forming a reaction chamber 120, a susceptor 14 disposed in the reaction chamber 120 and having a wafer 10 placed thereon, and a rotation device 16 that rotates the susceptor 14 together with the wafer 10. The susceptor 14 includes a pedestal 143 on which the wafer 10 is placed, and around the pedestal 143, a concave groove part 145 with a bottom that is depressed with respect to the pedestal 143 is formed. The pedestal 143 has the size that is contained within an outer periphery of the wafer 10 in a standard placement state. At the bottom part of the concave groove part 145, a through-hole 146 for introducing other gas than the raw material from outside the reaction chamber 120 to the concave groove part 145 is formed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an apparatus for manufacturing silicon carbide semiconductor wafers. [Background technology]

[0002] Conventionally, there has been known an apparatus that grows an epitaxial film, which is a semiconductor layer, on the surface of a silicon carbide semiconductor wafer by heating the wafer while rotating it while the wafer is placed on a susceptor in a reaction chamber into which a reactive gas containing a raw material gas is introduced (see, for example, Patent Document 1). In Patent Document 1, in order to prevent silicon carbide deposits from being formed on a pedestal of the susceptor on which the wafer is placed, the size of the pedestal is made smaller than the wafer, and a ring-shaped groove for storing the deposits is formed on the outside of the pedestal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-18772 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, as in Patent Document 1, when the size of the susceptor base is made smaller than the wafer, a part of the back surface of the wafer is exposed to the reaction gas containing the raw material gas that flows into the groove from the gap between the susceptor and the wafer, and the amount of film deposition increases on that part of the back surface of the wafer. An increase in the amount of film deposition on a part of the back surface of the wafer is undesirable because it causes transport problems in later processes such as photolithography.

[0005] An object of the present disclosure is to provide a silicon carbide semiconductor wafer manufacturing apparatus capable of suppressing the formation of deposits on a base of a susceptor while suppressing film deposition on the back surface side of the wafer. [Means for solving the problem]

[0006] The invention described in claim 1 is An apparatus for manufacturing silicon carbide semiconductor wafers, comprising: a reaction chamber forming section (12) for forming a reaction chamber (120) into which a reaction gas is introduced and in which a semiconductor layer is epitaxially grown on the front surface side of the wafer (10); a susceptor (14) disposed in the reaction chamber and on which a wafer is placed; a rotation device (16) for rotating the susceptor together with the wafer; The susceptor includes a base (143) on which a wafer is placed, and a bottomed groove (145) is formed around the periphery of the base, the groove being recessed relative to the base. When a state where the wafer is placed on the pedestal so that the center of the wafer coincides with the center of rotation of the susceptor is defined as a reference placement state, The pedestal is sized to fit inside the outer periphery of the wafer in a standard placement state, The reaction gas includes a source gas that is a source of the semiconductor layer, At the bottom of the groove, a through hole (146) is formed for introducing gas other than the raw material from the outside of the reaction chamber into the groove. And, The wafer has an orientation flat portion (11) formed by cutting a part of the outer periphery of the wafer in a straight line, When the minimum diameter of the wafer at the orientation flat is Dwof, the diameter of the pedestal is Db, and the groove width of the groove is Dg, the relationship between Dwof, Db, and Dg is as follows: Db+Dg <Dwof<Db+2Dg It is.

[0007] In this way, if the size of the pedestal is smaller than that of the wafer, the generation of silicon carbide deposits on the pedestal can be suppressed. In addition, a gas other than the raw material is introduced into the groove through a through hole formed in the bottom of the groove. This suppresses the reaction gas containing the raw material gas from flowing around the back surface of the wafer and dilutes the raw material gas on the back surface of the wafer, thereby suppressing deposition of a film on the back surface of the wafer.

[0008] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of a silicon carbide semiconductor manufacturing apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a schematic plan view of a susceptor with a wafer placed on a pedestal. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III of FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. [Diagram 5] FIG. 5 is an enlarged view of part V in FIG. [Figure 6] FIG. 11 is a schematic plan view of a susceptor according to a second embodiment. [Figure 7] 6 is a cross-sectional view taken along line VI-VI of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same reference numerals are used for parts that are the same as or equivalent to those described in the preceding embodiments, and the description thereof may be omitted. In addition, in the embodiments, when only a part of the components is described, the components described in the preceding embodiments can be applied to the other parts of the components. In the following embodiments, each embodiment can be partially combined with each other, even if not specifically stated, as long as it does not cause any trouble in combination.

[0011] (First embodiment) The present embodiment will be described with reference to Fig. 1 to Fig. 5. The apparatus shown in Fig. 1 is a manufacturing apparatus 1 for a silicon carbide semiconductor wafer (hereinafter also simply referred to as a wafer 10). This manufacturing apparatus 1 forms a semiconductor layer on the front surface side of the wafer 10 by epitaxial growth. The semiconductor layer is a crystalline thin film also called an epitaxial film.

[0012] 1, the manufacturing apparatus 1 has a chamber 12 that forms a reaction chamber 120 for epitaxially growing a semiconductor layer on the front surface side of a wafer 10. The chamber 12 is a reaction chamber forming part that forms the reaction chamber 120.

[0013] The chamber 12 is provided at its upper part with a gas supply unit 121 for supplying a reaction gas for growing a crystal thin film on the front surface side of the wafer 10. The reaction gas includes, for example, a source gas consisting of silane (SiH4) and propane (C3H8), a carrier gas consisting of hydrogen and hydrogen chloride (HCl), and a dopant gas consisting of nitrogen (N2). The chamber 12 is provided at its lower part with a gas exhaust unit 122 for exhausting the gas after the reaction. Although not shown, the gas exhaust unit 122 is connected to an exhaust device including a shutoff valve and a vacuum pump. The compositions of the source gas, carrier gas, and dopant gas are not limited to those described above, and may be other than those described above.

[0014] The gas supply unit 121 is located in the upper part of the chamber 12 and opens at a position facing the surface of the wafer 10. As a result, a reactive gas is supplied to the reaction chamber 120 toward the surface of the wafer 10 from a direction intersecting (approximately perpendicular to) the surface of the wafer 10. The manufacturing apparatus 1 of this embodiment has a downflow type gas supply structure that blows the reactive gas down toward the surface of the wafer 10.

[0015] A susceptor 14, which is a substrate holding jig that holds the wafer 10, is disposed in the reaction chamber 120. The susceptor 14 is installed above a rotation device 16 in the reaction chamber 120. The susceptor 14 will be described in detail later.

[0016] The rotating device 16 has a tubular portion 161, a rotating shaft 162, and a driving unit 163. The tubular portion 161 is a cylindrical member that supports the susceptor 14. The rotating shaft 162 is a shaft that rotates by the output of the driving unit 163. The rotating shaft 162 is connected to the tubular portion 161 so as to be rotatable therewith. The driving unit 163 is composed of a motor or the like that outputs a rotational force. In the rotating device 16 thus configured, when the rotating shaft 162 rotates by the output of the driving unit 163, the susceptor 14 rotates via the tubular portion 161.

[0017] When the susceptor 14 is placed on the upper part of the cylindrical portion 161, an opening 161a formed on the upper part is closed by the susceptor 14. As a result, a hollow chamber 160 is formed inside the cylindrical portion 161. The hollow chamber 160 is a space that is substantially separated from the reaction chamber 120 by the susceptor 14 and the cylindrical portion 161.

[0018] A main heater 18 is disposed in the hollow chamber 160 to heat the back side of the wafer 10 via the susceptor 14. The main heater 18 may be, for example, a carbon resistance heater. Heat from the main heater 18 is transferred to the reaction chamber 120 via the cylindrical portion 161 and the susceptor 14. Therefore, the main heater 18 also functions as a heater for heating the reaction chamber 120.

[0019] Although not shown, a susceptor lifting device is disposed in the hollow chamber 160 to assist the transfer robot in carrying the susceptor 14 on which the wafer 10 is placed into the reaction chamber 120 and in carrying the susceptor 14 out of the reaction chamber 120. For example, when carrying the susceptor 14 out, the susceptor lifting device raises the susceptor 14 and separates it from the cylindrical portion 161, thereby delivering the susceptor 14 to the transfer robot. Note that the manufacturing apparatus 1 does not necessarily carry in and out the susceptor 14 on which the wafer 10 is placed, and may carry in and out only the wafer 10 without moving the susceptor 14.

[0020] The rotating shaft 162 is composed of a cylindrical member. A gas introduction pipe 20 for supplying a purge gas to the hollow chamber 160 is disposed inside the rotating shaft 162. The gas introduction pipe 20 is connected to a gas introduction mechanism, and the purge gas is supplied through the gas introduction mechanism. Examples of the purge gas include inert gases such as argon (Ar), hydrogen (H2), and helium (He).

[0021] The manufacturing apparatus 1 includes an auxiliary heater 22 as a heater for heating the reaction chamber 120. The auxiliary heater 22 is disposed so as to surround the space above the susceptor 14 in the reaction chamber 120 so as to heat the reaction gas flowing from the gas supply unit 121 toward the wafer 10. The auxiliary heater 22 is disposed outside the chamber 12 to prevent deterioration due to the reaction gas. Note that the auxiliary heater 22 may be disposed inside the chamber 12 as long as measures against deterioration due to the reaction gas are taken for the auxiliary heater 22 itself or its periphery.

[0022] Specifically, the auxiliary heater 22 has an upper heater section 221 disposed near the gas supply section 121, a lower heater section 222 disposed near the susceptor 14, and a middle heater section 223 disposed between the upper heater section 221 and the lower heater section 222. For example, a carbon resistance heater can be used for the upper heater section 221, the lower heater section 222, and the middle heater section 223. If the auxiliary heater 22 is configured with a plurality of heater sections, the front surface side of the wafer 10 can be uniformly heated while suppressing temperature unevenness in the reaction chamber 120.

[0023] In the manufacturing apparatus 1 configured as above, the susceptor 14 on which the wafer 10 is placed is rotated at 600 rpm by the rotating device 16, while the reaction chamber 120 is heated to approximately 1600° C. by the main heater 18 and the auxiliary heater 22. The manufacturing apparatus 1 supplies a reaction gas from the gas supply unit 121 to the reaction chamber 120, and also supplies a purge gas from the gas introduction pipe 20 to the hollow chamber 160. As a result, an epitaxial film, which is a semiconductor layer, is formed on the front surface side of the wafer 10.

[0024] Next, details of the susceptor 14 of this embodiment will be described. The susceptor 14 is placed in the reaction chamber 120 with its surface in a substantially horizontal position. Since the susceptor 14 is placed in a high-temperature environment, it is made of, for example, isotropic graphite with a surface coated with silicon carbide (SiC). The wafer 10 is placed on the pedestal 143 so that the center of the wafer 10 coincides with the center of rotation Os of the susceptor 14. This placement state is called a reference placement state.

[0025] 2 and 3, the susceptor 14 includes a ring-shaped outer circumferential susceptor portion 141 and a disk-shaped inner circumferential susceptor portion 142 that covers the opening of the outer circumferential susceptor portion 141. The outer circumferential susceptor portion 141 and the inner circumferential susceptor portion 142 are separable from each other. Alternatively, the outer circumferential susceptor portion 141 and the inner circumferential susceptor portion 142 may be integrally configured so as to be inseparable.

[0026] The susceptor 14 has a pedestal 143 on which the wafer 10 is placed. The pedestal 143 is configured with a single ring-shaped protrusion surrounding the rotation center Os of the susceptor 14. The pedestal 143 protrudes upward from the surface of the inner circumferential susceptor portion 142. The pedestal 143 is molded integrally with the inner circumferential susceptor portion 142. The pedestal 143 may be configured separately from the inner circumferential susceptor portion 142.

[0027] The susceptor 14 also has a cover 144 that covers the outer peripheral surface of the wafer 10. The cover 144 has a cylindrical shape centered on the rotation center Os of the susceptor 14. The base 143 protrudes upward from the surfaces of the outer peripheral susceptor portion 141 and the inner peripheral susceptor portion 142. The cover 144 is installed on the upper portion of the inner peripheral susceptor portion 142. The cover 144 may be molded integrally with the inner peripheral susceptor portion 142.

[0028] The susceptor 14 is provided with a pedestal 143 and a cover 144 with respect to the inner peripheral susceptor portion 142, so that a bottomed concave groove portion 145 recessed with respect to the pedestal 143 is formed around the pedestal 143. This concave groove portion 145 is constituted by the surface of the inner peripheral susceptor portion 142, the outer surface of the pedestal 143, and the inner surface of the cover 144. Note that the concave groove portion 145 may be integrally formed, for example, by digging down the surface of the inner peripheral susceptor portion 142 with a processing jig or the like.

[0029] The protruding height Hc of the cover 144 is such that the inner wall surface of the cover 144 faces the outer peripheral surface of the wafer 10. That is, the protruding height Hc of the cover 144 is larger than the protruding height Hb of the pedestal 143 (Hc>Hb). Specifically, the protruding height Hc of the cover 144 is substantially equal to the height obtained by adding the protruding height Hb of the pedestal 143 and the thickness Tw of the wafer 10 (Hc≒Hb + Tw). Also, the inner diameter Dc of the cover 144 is larger than the diameter Dx of the wafer 10 and the outer diameter Db of the pedestal 143. The diameter Dw of the wafer 10 is larger than the outer diameter Db of the pedestal 143 (Db<Dw<Dc). Note that the diameter Dw of the wafer 10 is the diameter at a portion not including the oriflange portion 11 described later.

[0030] The groove width Dg of the concave groove portion 145 is half of the value obtained by subtracting the outer diameter Db of the pedestal 143 from the inner diameter Dc of the cover 144 (Dg=(Dc - Db) / 2). For this reason, the diameter Dw of the wafer 10 is smaller than the value obtained by adding the outer diameter Db of the pedestal 143 to the value obtained by doubling the groove width Dg (Dw<Db + 2Dg).

[0031] The wafer 10 of the present embodiment has an oriflange portion 11 in which a part of the outer peripheral edge of the wafer 10 is linearly cut. The oriflange portion 11 is provided to indicate the crystal orientation of the wafer 10. The wafer 10 has a minimum diameter Dwof at a portion including the oriflange portion 11 that is smaller than the diameter Dw.

[0032] Here, for example, when the susceptor 14 is rotated in a state where the center of the wafer 10 is misaligned with respect to the rotation center Os of the susceptor 14, the position of the wafer 10 may be significantly misaligned due to centrifugal force acting on the wafer 10. When the wafer 10 is misaligned, the pedestal 143 on which the wafer 10 is placed in the susceptor 14 is exposed to a reaction gas, which may cause a deposit of silicon carbide to occur on the pedestal 143. If a deposit occurs on the pedestal 143, the deposit will be transferred to the back surface of the wafer 10 when the wafer 10 is next placed on the pedestal 143, which is undesirable because it may cause a transport failure in a later process such as photolithography.

[0033] In contrast, the susceptor 14 is configured so that the pedestal 143 is not exposed to the reaction gas when the wafer 10 is placed on the pedestal 143. That is, the pedestal 143 is sized to be contained inside the outer periphery of the wafer 10 in a standard placement state. Specifically, as shown in Fig. 4, the susceptor 14 is configured so that the minimum diameter Dwof of the wafer 10, the outer diameter Db of the pedestal 143, and the groove width Dg satisfy the following mathematical formula F1.

[0034] Db+Dg <Dwof<Db+2Dg ···(F1) If the minimum diameter Dwof of the wafer 10 is larger than the sum of the outer diameter Db of the pedestal 143 and the groove width Dg, the pedestal 143 is covered with the wafer 10 even if the wafer 10 is displaced to a position where the outer peripheral surface of the wafer 10 abuts on the cover 144. In other words, even if the wafer 10 is displaced, the pedestal 143 is prevented from being exposed to the reaction gas.

[0035] However, if the size of the pedestal 143 of the susceptor 14 is made smaller than the wafer 10 as described above, a part of the back surface of the wafer 10 is exposed to the reaction gas flowing into the concave groove portion 145 from the gap between the susceptor 14 and the wafer 10. Further, if the concave groove portion 145 communicates only with the reaction chamber 120 through the gap between the wafer 10 and the cover 144, the reaction gas is likely to stay because the concave groove portion 145 becomes a dead end. When the back surface of the wafer 10 is exposed to the reaction gas, the film deposition amount increases on a part of the back surface of the wafer 10. An increase in the film deposition amount on a part of the back surface of the wafer 10 is not preferable because conveyance failure occurs in a subsequent process such as photolithography.

[0036] Based on these considerations, the susceptor 14 has a plurality of through holes 146 formed at the bottom of the concave groove portion 145 for introducing a gas other than the source gas from the outside of the reaction chamber 120 into the concave groove portion 145. The opening shape of the through hole 146 is a long hole shape extending along the rotation direction Rs. The opening shape of the through hole 146 is not limited to the long hole shape, and may be, for example, a circular shape or an elliptical shape.

[0037] As shown in FIGS. 4 and 5, the through hole 146 penetrates the front and back of the susceptor 14. The through hole 146 has a front side opening portion 147 that opens to the front surface side of the susceptor 14, a back side opening portion 148 that opens to the back surface side of the susceptor 14, and a hole inner wall 149 extending from the front side opening portion 147 to the back side opening portion 148.

[0038] The interval Dh1 between the inner sides of the through holes 146 facing each other across the rotation center Os of the susceptor 14 is larger than the outer diameter Db of the pedestal 143 and smaller than the diameter Dw of the wafer 10 (Db < Dh1 < Dw). Further, the interval Dh2 between the outer sides of the through holes 146 facing each other across the rotation center Os of the susceptor 14 is smaller than the inner diameter Dc of the cover 144 (Dh2 < Dc).

[0039] 2, a plurality of through holes 146 are formed in the bottom of the recessed groove portion 145. The through holes 146 are formed in eight different positions in the rotation direction Rs of the bottom of the recessed groove portion 145. That is, eight through holes 146 are formed in the susceptor 14. The eight through holes 146 are formed in the susceptor 14 so as to be rotationally symmetric. Moreover, the eight through holes 146 are formed at equal intervals in the rotation direction Rs.

[0040] A front side opening 147 of the through hole 146 opens to the bottom of the groove portion 145 of the susceptor 14. A back side opening 148 of the through hole 146 opens to a portion of the susceptor 14 that defines the hollow chamber 160. As a result, the groove portion 145 communicates with the hollow chamber 160 via the through hole 146. As shown in FIG. 5, the purge gas inside the tube portion 161 is supplied to the groove portion 145 via the through hole 146 formed in the groove portion 145.

[0041] The entire hole inner wall 149 of the through hole 146 extends along the rotation axis direction of the susceptor 14. The hole inner wall 149 of the through hole 146 has a first inner wall 1491 along the radial direction centered on the rotation center Os of the susceptor 14, and a second inner wall 1492 along the circumferential direction centered on the rotation center Os of the susceptor 14 (i.e., the rotation direction Rs of the susceptor 14). The first inner wall 1491 and the second inner wall 1492 each extend along the rotation axis direction of the susceptor 14.

[0042] In the silicon carbide semiconductor wafer manufacturing apparatus 1 described above, the pedestal 143 is sized so that the pedestal 143 fits inside the outer periphery of the wafer 10 in the standard placement state. In this way, if the size of the pedestal 143 is smaller than the wafer 10, the generation of silicon carbide deposits on the pedestal 143 can be suppressed. In addition, a through hole 146 is formed at the bottom of the groove portion 145 of the susceptor 14 to introduce gas other than the source gas from outside the reaction chamber 120 into the groove portion 145. This suppresses the source gas from flowing around the back surface of the wafer 10 and dilutes the source gas on the back surface side of the wafer 10, so that deposition of a film on the back surface side of the wafer 10 can be suppressed.

[0043] Moreover, according to this embodiment, the following effects can be obtained.

[0044] (1) Susceptor 14 is configured so that the minimum diameter Dwof of wafer 10, the outer diameter Db of pedestal 143, and the groove width Dg satisfy the above-mentioned formula F1. With this, even when wafer 10 having orientation flat 11 is placed on pedestal 143, the generation of silicon carbide deposits on pedestal 143 can be suppressed.

[0045] (2) In the susceptor 14, the purge gas inside the cylindrical portion 161 is supplied to the groove portion 145 via the through-holes 146 formed in the groove portion 145. As a result, the purge gas for purging the inside of the cylindrical portion 161 can be supplied to the groove portion 145 as another gas, so that deposition of a film on the back side of the wafer 10 can be suppressed without adding a dedicated device for supplying another gas to the groove portion 145.

[0046] (3) The manufacturing apparatus 1 of this embodiment has a downflow type gas supply structure in which reactive gas is supplied to the reaction chamber 120 from a direction intersecting the surface of the wafer 10 toward the surface of the wafer 10. This causes the pressure of the reactive flow supplied to the reaction chamber 120 to act in a direction pressing the wafer 10 against the pedestal 143. Therefore, misalignment of the wafer 10 caused by the rotation of the susceptor 14 is suppressed compared to a sideflow type gas supply structure in which reactive gas is supplied to the reaction chamber 120 from a direction along the surface of the wafer 10 in parallel with the surface of the wafer 10.

[0047] Second embodiment Next, a second embodiment will be described with reference to Figures 6 and 7. In this embodiment, differences from the first embodiment will be mainly described.

[0048] As shown in FIG. 6 and FIG. 7, the base 143 of this embodiment is composed of a plurality of ring-shaped protrusions 143a, 143b surrounding the rotation center Os of the susceptor 14. The plurality of protrusions 143a, 143b have different diameters. The plurality of protrusions 143a, 143b are configured in a concentric circular shape centered on the rotation center Os. In this embodiment, the outer diameter of the outer protrusion 143a of the plurality of protrusions 143a, 143b corresponds to the outer diameter Db of the base 143. The plurality of protrusions 143a, 143b may be configured so that their centers coincide with each other, or may not be configured so that their centers do not coincide with each other.

[0049] The rest is the same as in the first embodiment. The manufacturing apparatus 1 of this embodiment can obtain the same effects as in the first embodiment, which are achieved by a configuration common to the first embodiment or an equivalent configuration.

[0050] Moreover, according to this embodiment, the following effects can be obtained.

[0051] (1) In this embodiment, the pedestal 143 is configured with a plurality of ring-shaped protrusions 143a, 143b surrounding the rotation center Os of the susceptor 14. This ensures a sufficient contact area between the pedestal 143 and the wafer 10, thereby preventing unintended positional displacement of the wafer 10.

[0052] (Other embodiments) Representative embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments and can be modified in various ways, for example, as described below.

[0053] In the above embodiment, the groove portion 145 communicates with the hollow chamber 160 via the through-hole 146, and the purge gas inside the cylindrical portion 161 is supplied to the groove portion 145 via the through-hole 146. However, the supply structure of the inert gas is not limited to this. The manufacturing apparatus 1 may include a gas introduction mechanism that introduces an inert gas to the back side of the susceptor 14, and the inert gas may be supplied to the groove portion 145 via the through-hole 146 by the gas supply mechanism. In addition, the manufacturing apparatus 1 may be configured to supply the inert gas to the groove portion 145 via a dedicated gas path through which the inert gas flows and the through-hole 146, without passing through the hollow chamber 160. The other gas supplied to the groove portion 145 via the through-hole 146 is not limited to an inert gas such as a purge gas, and may be, for example, a carrier gas such as hydrogen or hydrogen chloride.

[0054] In the through-hole 146 in the above-described embodiment, the entire hole inner wall 149 extends along the rotation axis direction of the susceptor 14, but is not limited thereto. For example, the first inner wall 1491 of the hole inner wall 149 of the through-hole 146 may have at least a portion connected to the back side opening 148 inclined in a direction from the back side opening 148 to the front side opening 147 from the rear to the front in the rotation direction Rs of the susceptor 14. With this, when the susceptor 14 is rotated, the inert gas easily flows from the back side of the susceptor 14 toward the recessed groove portion 145, so that the intrusion of the reactive gas to the back side of the wafer 10 can be sufficiently suppressed.

[0055] The susceptor 14 in the above embodiment has the cover 144, but is not limited thereto and may not have the cover 144. In addition, the susceptor 14 has the through-holes 146 formed substantially entirely inside the wafer 10, but is not limited thereto. The susceptor 14 may have the through-holes 146 formed entirely outside the wafer 10. In addition, the susceptor 14 has eight through-holes 146 formed therein, but is not limited thereto, and may have one to seven, or nine or more through-holes 146 formed therein. When a plurality of through-holes 146 are formed, the positions of the through-holes 146 can be set arbitrarily. The pedestal 143 is not limited to a ring-shaped protrusion, and may have any shape (for example, a cylindrical protrusion). The wafer 10 placed on the susceptor 14 is not limited to one including the orientation flat 11, and may be one without the orientation flat 11 or one provided with a notch instead of the orientation flat 11, for example.

[0056] The manufacturing apparatus 1 of the above embodiment has the main heater 18 and the auxiliary heater 22 as heaters for heating the reaction chamber 120, but is not limited to this, and may have either the main heater 18 or the auxiliary heater 22.

[0057] Although the manufacturing apparatus 1 of the above-described embodiment has a downflow type gas supply structure, the present invention is not limited to this and may have, for example, a sideflow type gas supply structure.

[0058] In the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where it is particularly expressly stated that they are essential or where they are clearly considered to be essential in principle.

[0059] In the above-described embodiments, when numerical values ​​such as the number, values, amounts, ranges, etc. of components of the embodiments are mentioned, they are not limited to the specific numbers unless it is specifically stated as required or unless it is clearly limited to a specific number in principle.

[0060] In the above-described embodiments, when referring to the shapes, positional relationships, etc. of components, etc., there is no limitation to those shapes, positional relationships, etc., unless specifically stated or in principle limited to a specific shape, positional relationship, etc. [Explanation of symbols]

[0061] 10 Wafers 12 Chamber (reaction chamber forming part) 120 Reaction chamber 14 Susceptor 143 Pedestal 144 Concave groove part 146 Through hole 16 Rotating device

Claims

1. An apparatus for manufacturing silicon carbide semiconductor wafers, comprising: a reaction chamber forming section (12) for forming a reaction chamber (120) into which a reaction gas is introduced and in which a semiconductor layer is epitaxially grown on the front surface side of the wafer (10); a susceptor (14) disposed in the reaction chamber and on which the wafer is placed; a rotation device (16) for rotating the susceptor together with the wafer; The susceptor includes a base (143) on which the wafer is placed, and a bottomed groove (145) recessed relative to the base is formed around the periphery of the base, When the state where the wafer is placed on the pedestal so that the center of the wafer coincides with the rotation center of the susceptor is defined as a reference placement state, the pedestal is sized to be accommodated inside the outer periphery of the wafer in the standard placement state, the reaction gas contains a source gas that is a source of the semiconductor layer, a through hole (146) is formed in the bottom of the groove portion to introduce a gas other than the source gas from outside the reaction chamber into the groove portion; The wafer has an orientation flat portion (11) formed by cutting a part of the outer periphery of the wafer in a straight line, When the minimum diameter of the wafer at the orientation flat portion is Dwof, the diameter of the pedestal is Db, and the groove width of the groove portion is Dg, the relationship between Dwof, Db, and Dg is as follows: Db+Dg<Dwof<Db+2Dg A silicon carbide semiconductor wafer manufacturing apparatus.

2. 2. The silicon carbide semiconductor wafer manufacturing apparatus according to claim 1, wherein the pedestal is configured with a plurality of ring-shaped protrusions (143a, 143b) surrounding a rotation center of the susceptor.

3. The rotating device has a cylindrical portion (161) that supports the susceptor, A heater (18) for heating the wafer is disposed inside the cylindrical portion, and a purge gas for purging the inside of the cylindrical portion is supplied as the other gas; 3 . The silicon carbide semiconductor wafer manufacturing apparatus according to claim 1 , wherein the purge gas inside the cylindrical portion is supplied to the groove portion via the through-hole formed in the groove portion. 4 .

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