JP7604848B2 - Silicon carbide semiconductor wafer manufacturing equipment - Google Patents

Description

This disclosure relates to a manufacturing apparatus for silicon carbide semiconductor wafers.

Conventionally, there is 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 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 the 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 is formed on the outside of the pedestal to accumulate the deposits.

JP 2011-18772 A

However, as in Patent Document 1, when the size of the susceptor base is made smaller than the wafer, part of the back surface of the wafer is exposed to the reaction gas, including 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 can cause transport problems in later processes such as photolithography.

The present disclosure aims to provide a silicon carbide semiconductor wafer manufacturing apparatus that can suppress the formation of deposits on the susceptor base while suppressing film formation on the back side of the wafer.

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) recessed relative to the base is formed around the periphery of 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 edge of the wafer in a standard placement state,
The reaction gas includes a source gas that is a source of the semiconductor layer,
A through hole (146) is formed in the bottom of the groove for introducing gas other than the raw material from the outside of the reaction chamber into the groove ,
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.

In this way, if the size of the pedestal is smaller than the wafer, the occurrence of silicon carbide deposits on the pedestal can be suppressed. In addition, the configuration is such that gases other than the raw material are introduced into the groove portion through through holes formed in the bottom of the groove portion. This suppresses the reaction gas containing the raw material gas from flowing around to the back surface of the wafer and dilutes the raw material gas on the back surface of the wafer, thereby suppressing the deposition of a film on the back surface of the wafer.

The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below.

1 is a schematic configuration diagram of a silicon carbide semiconductor manufacturing apparatus according to a first embodiment. FIG. 2 is a schematic plan view of a susceptor with a wafer placed on a pedestal. FIG. 3 is a cross-sectional view taken along line III-III of FIG. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. FIG. 5 is an enlarged view of a portion V in FIG. 4 . FIG. 11 is a schematic plan view of a susceptor according to a second embodiment. FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG.

Embodiments of the present disclosure will be described below with reference to the drawings. In the following embodiments, parts that are the same as or equivalent to those described in the preceding embodiments may be given the same reference numerals, and their description may be omitted. In addition, in the embodiments where only some of the components are described, the components described in the preceding embodiments may be applied to the other parts of the components. The following embodiments may be partially combined with each other, as long as the combination does not cause any problems, even if not specifically stated.

First Embodiment
This embodiment will be described with reference to Figures 1 to 5. The apparatus shown in Figure 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 epitaxially grows a semiconductor layer on the front surface side of the wafer 10. The semiconductor layer is a crystalline thin film also called an epitaxial film.

As shown in FIG. 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 the wafer 10. The chamber 12 is a reaction chamber forming part that forms the reaction chamber 120.

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 (SiH ₄ ) and propane (C ₃ H ₈ ), a carrier gas consisting of hydrogen and hydrogen chloride (HCl), and a dopant gas consisting of nitrogen (N ₂ ). 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.

The gas supply unit 121 is located at the top of the chamber 12 and opens at a position facing the surface of the wafer 10. This allows reactive gas to be 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 reactive gas down toward the surface of the wafer 10.

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 the rotation device 16 in the reaction chamber 120. Details of the susceptor 14 will be described later.

The rotating device 16 has a tube portion 161, a rotating shaft 162, and a driving unit 163. The tube 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 tube portion 161 so that they can rotate together. The driving unit 163 is composed of a motor or the like that outputs a rotational force. In the rotating device 16 configured in this manner, when the rotating shaft 162 rotates by the output of the driving unit 163, the susceptor 14 rotates via the tube portion 161.

When the susceptor 14 is placed on top of the cylindrical portion 161, the opening 161a formed on the top is closed by the susceptor 14. This forms a hollow chamber 160 inside the cylindrical portion 161. This hollow chamber 160 is a space that is essentially separated from the reaction chamber 120 by the susceptor 14 and the cylindrical portion 161.

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. The heat of 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 to heat the reaction chamber 120.

Although not shown, a susceptor lifting device is disposed in the hollow chamber 160 to assist the transport 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 transferring the susceptor 14 to the transport robot. Note that the manufacturing apparatus 1 does not necessarily carry in and out the susceptor 14 on which the wafer 10 is placed, but may carry in and out only the wafer 10 without moving the susceptor 14.

The rotating shaft 162 is made 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 (H ₂ ), and helium (He).

The manufacturing apparatus 1 is equipped with an auxiliary heater 22 as a heater for heating the reaction chamber 120. The auxiliary heater 22 is arranged to surround the space above the susceptor 14 in the reaction chamber 120 so that the reaction gas flowing from the gas supply unit 121 toward the wafer 10 is heated. The auxiliary heater 22 is arranged outside the chamber 12 to avoid deterioration due to the reaction gas. Note that the auxiliary heater 22 may be arranged 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 surroundings.

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

In the manufacturing apparatus 1 configured in this manner, 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 auxiliary heater 22. The manufacturing apparatus 1 then supplies a reaction gas from the gas supply unit 121 to the reaction chamber 120, and 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.

Next, the 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 silicon carbide (SiC) coating on the surface. 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 the reference placement state.

As shown in Figures 2 and 3, the susceptor 14 has a ring-shaped outer peripheral susceptor portion 141 and a disk-shaped inner peripheral susceptor portion 142 that covers the opening of the outer peripheral susceptor portion 141. The outer peripheral susceptor portion 141 and the inner peripheral susceptor portion 142 are separable from each other. The outer peripheral susceptor portion 141 and the inner peripheral susceptor portion 142 may be integrally configured so as not to be separable.

The susceptor 14 has a pedestal 143 on which the wafer 10 is placed. The pedestal 143 is composed of 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 periphery susceptor portion 142. The pedestal 143 is molded integrally with the inner periphery susceptor portion 142. The pedestal 143 may be configured separately from the inner periphery susceptor portion 142.

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 part of the inner peripheral susceptor portion 142. The cover 144 may be molded integrally with the inner peripheral susceptor portion 142.

The susceptor 14 has a base 143 and a cover 144 provided on the inner circumferential susceptor portion 142, and a bottomed groove portion 145 recessed into the base 143 is formed around the base 143. This groove portion 145 is formed by the surface of the inner circumferential susceptor portion 142, the outer surface of the base 143, and the inner surface of the cover 144. Note that the groove portion 145 may be integrally formed, for example, by digging into the surface of the inner circumferential susceptor portion 142 with a processing jig or the like.

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. In other words, the protruding height Hc of the cover 144 is greater than the protruding height Hb of the pedestal 143 (Hc>Hb). Specifically, the protruding height Hc of the cover 144 is approximately 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). The inner diameter Dc of the cover 144 is greater 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 greater than the outer diameter Db of the pedestal 143 (Db<Dw<Dc). The diameter Dw of the wafer 10 is the diameter at a portion that does not include the orientation flat portion 11 described below.

The groove width Dg of the recessed groove portion 145 is half the inner diameter Dc of the cover 144 minus the outer diameter Db of the pedestal 143 (Dg = (Dc - Db) / 2). Therefore, the diameter Dw of the wafer 10 is smaller than twice the groove width Dg plus the outer diameter Db of the pedestal 143 (Dw < Db + 2Dg).

In this embodiment, the wafer 10 has an orientation flat 11, which is a linear cut on part of the outer edge of the wafer 10. The orientation flat 11 is provided to indicate the crystal orientation of the wafer 10. The minimum diameter Dwof of the wafer 10 at the portion including the orientation flat 11 is smaller than the diameter Dw.

Here, for example, if the susceptor 14 is rotated with the center of the wafer 10 misaligned with respect to the center of rotation Os of the susceptor 14, the position of the wafer 10 may be significantly misaligned due to centrifugal force acting on the wafer 10. If the wafer 10 is misaligned, the pedestal 143 on which the wafer 10 is placed in the susceptor 14 may be exposed to reaction gas, which may cause silicon carbide deposits to form on the pedestal 143. If deposits form on the pedestal 143, the next time the wafer 10 is placed on the pedestal 143, the deposits will be transferred to the back surface of the wafer 10, which may cause transport problems in subsequent processes such as photolithography, which is undesirable.

In response to this, the susceptor 14 is designed 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 so that in the standard placement state, the pedestal 143 fits inside the outer periphery of the wafer 10. 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.

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, even if the outer peripheral surface of the wafer 10 is displaced to a position where it hits the cover 144, the wafer 10 can be moved to the position where the outer peripheral surface of the wafer 10 hits the cover 144 without being moved to the position where the outer peripheral surface of the wafer 10 hits the cover 144. is covered with the wafer 10. In other words, even if the wafer 10 is misaligned, the pedestal 143 is prevented from being exposed to the reaction gas.

However, as described above, if the size of the pedestal 143 of the susceptor 14 is made smaller than the wafer 10, a part of the back surface of the wafer 10 is exposed to the reaction gas flowing into the groove portion 145 from the gap between the susceptor 14 and the wafer 10. In addition, if the groove portion 145 is connected only to the reaction chamber 120 through the gap between the wafer 10 and the cover 144, the groove portion 145 becomes a dead end, and the reaction gas is likely to stagnate. When the back surface of the wafer 10 is exposed to the reaction gas, the amount of film deposition increases on a part of the back surface of the wafer 10. An increase in the amount of film deposition on a part of the back surface of the wafer 10 is undesirable because it can cause transport problems in later processes such as photolithography.

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

As shown in Figures 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 147 that opens on the front side of the susceptor 14, a back-side opening 148 that opens on the back side of the susceptor 14, and a hole inner wall 149 that extends from the front-side opening 147 to the back-side opening 148.

The distance Dh1 between the inner sides of the through holes 146 that face each other across the center of rotation 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). The distance Dh2 between the outer sides of the through holes 146 that face each other across the center of rotation Os of the susceptor 14 is smaller than the inner diameter Dc of the cover 144 (Dh2<Dc).

As shown in FIG. 2, a plurality of through holes 146 are formed in the bottom of the groove portion 145. The through holes 146 are formed in eight different locations in the rotation direction Rs of the bottom of the groove portion 145. That is, eight through holes 146 are formed in the susceptor 14. These eight through holes 146 are formed in the susceptor 14 so as to be rotationally symmetric. Furthermore, the eight through holes 146 are formed at equal intervals in the rotation direction Rs.

The front opening 147 of the through hole 146 opens to the bottom of the groove portion 145 of the susceptor 14. The back 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.

The entire inner wall 149 of the through hole 146 extends along the rotation axis direction of the susceptor 14. The inner wall 149 of the through hole 146 has a first inner wall 1491 extending along the radial direction centered on the rotation center Os of the susceptor 14, and a second inner wall 1492 extending 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.

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 mounting 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 gases other than the raw material gas from outside the reaction chamber 120 into the groove portion 145. This suppresses the raw material gas from wrapping around the back surface of the wafer 10 and dilutes the raw material gas on the back surface side of the wafer 10, thereby suppressing deposition of a film on the back surface side of the wafer 10.

In addition, this embodiment provides the following advantages:

(1) 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 above-mentioned formula F1. This makes it possible to suppress the occurrence of silicon carbide deposits on the pedestal 143, even when a wafer 10 having an orientation flat portion 11 is placed on the pedestal 143.

(2) In the susceptor 14, the purge gas inside the cylindrical portion 161 is supplied to the groove portion 145 through the through-holes 146 formed in the groove portion 145. This allows the purge gas for purging the inside of the cylindrical portion 161 to 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.

(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 from the reactive flow supplied to the reaction chamber 120 to act in a direction that presses 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 and parallel to the surface of the wafer 10.

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.

As shown in Figures 6 and 7, the base 143 of this embodiment is composed of multiple ring-shaped protrusions 143a, 143b surrounding the rotation center Os of the susceptor 14. The multiple protrusions 143a, 143b have different diameters. The multiple 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 multiple protrusions 143a, 143b corresponds to the outer diameter Db of the base 143. The multiple protrusions 143a, 143b may be configured so that their centers coincide with each other, or so that their centers do not coincide with each other.

Otherwise, it is the same as the first embodiment. The manufacturing device 1 of this embodiment can obtain the same effects as the first embodiment, which are achieved from a common configuration or an equivalent configuration to the first embodiment.

In addition, this embodiment provides the following advantages:

(1) In this embodiment, the pedestal 143 is composed of multiple ring-shaped protrusions 143a, 143b that surround 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 misalignment of the wafer 10.

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.

In the above embodiment, the groove portion 145 communicates with the hollow chamber 160 through the through-hole 146, and the purge gas inside the tube portion 161 is supplied to the groove portion 145 through the through-hole 146, but the inert gas supply structure 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 through the through-hole 146 by the gas supply mechanism. In addition, the manufacturing apparatus 1 may be structured so that the inert gas is supplied to the groove portion 145 through 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 through the through-hole 146 is not limited to an inert gas such as a purge gas, but may be, for example, a carrier gas such as hydrogen or hydrogen chloride.

In the above-described embodiment, the through-hole 146 has the entire hole inner wall 149 extending 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 opening 148 inclined in the direction from the back opening 148 to the front opening 147 from the rear to the front in the rotation direction Rs of the susceptor 14. This makes it easier for the inert gas to flow from the back side of the susceptor 14 toward the groove portion 145 when the susceptor 14 is rotated, so that the inert gas can be sufficiently prevented from flowing around the back side of the wafer 10.

The susceptor 14 in the above embodiment has a cover 144, but is not limited to this, and may not have a cover 144. In addition, the susceptor 14 has the through-holes 146 formed almost entirely inside the wafer 10, but is not limited to this. The susceptor 14 may have the through-holes 146 formed entirely outside the wafer 10. Furthermore, the susceptor 14 has eight through-holes 146 formed, but is not limited to this, and may have 1 to 7, or 9 or more through-holes 146 formed. When multiple 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 convex portion, and may have any shape (for example, a cylindrical convex portion). The wafer 10 placed on the susceptor 14 is not limited to one that includes an orientation flat portion 11, and may be one that does not have an orientation flat portion 11 or one that has a notch instead of the orientation flat portion 11.

The manufacturing apparatus 1 of the above embodiment has a main heater 18 and an 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.

The manufacturing apparatus 1 in the above-described embodiment has a downflow type gas supply structure, but is not limited thereto, and may have, for example, a sideflow type gas supply structure.

It goes without saying that in the above-described embodiments, the elements constituting the embodiments are not necessarily essential, except in cases where they are specifically stated as essential or where they are clearly considered essential in principle.

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, except when it is expressly stated that they are essential or when they are clearly limited to a specific number in principle.

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 otherwise or in principle limited to a specific shape, positional relationship, etc.

10 Wafer 12 Chamber (reaction chamber forming part)
120 Reaction chamber 14 Susceptor 143 Pedestal 144 Groove portion 146 Through hole 16 Rotation device

Claims (3)

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. 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. 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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